Main

Bis[2-(N,N-Dimethylaminoethyl)] Ether in High-Performance Aerospace Adhesives: A Comprehensive Overview

Introduction

Bis[2-(N,N-Dimethylaminoethyl)] ether, commonly known as BDMAEE, is a tertiary amine catalyst extensively employed in various industrial applications, notably in polyurethane foam manufacturing and, increasingly, in high-performance aerospace adhesives. Its unique molecular structure, featuring two tertiary amine groups separated by an ether linkage, renders it a highly effective catalyst for both the gelation (polyol-isocyanate reaction) and blowing (water-isocyanate reaction) processes in polyurethane chemistry. In the context of aerospace adhesives, BDMAEE serves as a crucial component in accelerating the curing reaction, enhancing the mechanical properties, and improving the overall performance characteristics required for demanding aerospace applications. This article provides a comprehensive overview of BDMAEE, exploring its chemical properties, mechanism of action, application in aerospace adhesives, advantages, disadvantages, and future trends, drawing upon both domestic and international research.

1. Chemical Properties and Characteristics of BDMAEE

Chemical Name: Bis[2-(N,N-Dimethylaminoethyl)] ether
Synonyms: DABCO® NE1060; Jeffcat® ZF-10; Polycat® SA-1/10; Dimorpholinodiethylether
CAS Registry Number: 3033-62-3
Molecular Formula: C₁₂H₂₆N₂O
Molecular Weight: 214.34 g/mol
Structural Formula: (CH₃)₂N-CH₂CH₂-O-CH₂CH₂-N(CH₃)₂
Appearance: Colorless to pale yellow liquid
Odor: Amine-like odor
Boiling Point: 189-192 °C (at 760 mmHg)
Flash Point: 68 °C (closed cup)
Density: 0.850-0.855 g/cm³ at 25 °C
Viscosity: Low viscosity
Solubility: Soluble in water, alcohols, ethers, and most organic solvents.
Stability: Relatively stable under normal storage conditions, but may react with strong acids and oxidizing agents.

Table 1: Key Physical and Chemical Properties of BDMAEE

Property	Value	Unit
Molecular Weight	214.34	g/mol
Boiling Point	189-192	°C
Flash Point	68	°C
Density	0.850-0.855	g/cm³
Vapor Pressure	Low	N/A
Solubility (Water)	Soluble	N/A

2. Mechanism of Action as a Catalyst

BDMAEE functions as a tertiary amine catalyst, accelerating the reactions in both polyurethane foam and adhesive systems. Its catalytic activity stems from its ability to:

Promote the Polyol-Isocyanate (Gelation) Reaction: The nitrogen atoms in BDMAEE have lone pairs of electrons that can coordinate with the isocyanate group (-NCO), thereby activating the isocyanate towards nucleophilic attack by the hydroxyl group (-OH) of the polyol. This lowers the activation energy of the reaction, resulting in a faster polymerization rate.
Promote the Water-Isocyanate (Blowing) Reaction (where applicable): In polyurethane foam systems, water reacts with isocyanate to produce carbon dioxide (CO₂), which acts as the blowing agent. BDMAEE also catalyzes this reaction by activating the isocyanate towards nucleophilic attack by water.

The mechanism can be simplified as follows:

BDMAEE (B:) reacts with isocyanate (-NCO) to form an activated complex [B:…NCO].
The activated isocyanate complex is more susceptible to nucleophilic attack by the polyol (-OH) or water (H₂O).
The reaction proceeds, forming the urethane linkage or urea linkage (and CO₂ in the case of water reaction), and regenerating the BDMAEE catalyst.

3. Application in High-Performance Aerospace Adhesives

Aerospace adhesives are subjected to extreme conditions, including wide temperature ranges, high stresses, and exposure to various chemicals and environmental factors. Therefore, they require exceptional mechanical properties, high thermal stability, and excellent resistance to environmental degradation. BDMAEE is often incorporated into aerospace adhesive formulations, particularly in epoxy and polyurethane-based systems, to enhance their performance.

3.1. Epoxy Adhesives:

In epoxy adhesives, BDMAEE acts as an accelerator for the curing reaction between the epoxy resin and the curing agent (e.g., amines, anhydrides). It promotes the ring-opening polymerization of the epoxy groups, leading to a faster cure rate and improved crosslinking density. This results in adhesives with:

Higher Bond Strength: Increased crosslinking density leads to a stronger and more durable adhesive bond.
Improved Thermal Stability: A more robust crosslinked network provides better resistance to high temperatures.
Enhanced Chemical Resistance: Increased crosslinking density reduces the permeability of the adhesive to solvents and other chemicals.
Faster Cure Time: Reduced cycle time in manufacturing processes.

Table 2: Effect of BDMAEE on Epoxy Adhesive Properties (Example)

Property	Without BDMAEE	With BDMAEE (0.5 wt%)	Improvement (%)	Test Method
Tensile Shear Strength (at 25°C)	25 MPa	32 MPa	28%	ASTM D1002
Glass Transition Temperature (Tg)	120 °C	135 °C	12.5%	DSC
Lap Shear Strength (after 1000h at 80°C)	20 MPa	28 MPa	40%	ASTM D1002

3.2. Polyurethane Adhesives:

In polyurethane adhesives, BDMAEE catalyzes the reaction between the polyol and isocyanate components. This is particularly important in two-part polyurethane adhesive systems used in aerospace applications. The benefits of using BDMAEE in polyurethane adhesives include:

Controlled Cure Rate: BDMAEE allows for precise control over the curing process, enabling optimization of the adhesive’s working time and final properties.
Improved Adhesion to Various Substrates: The catalytic effect of BDMAEE can improve the wetting and adhesion of the adhesive to different substrates, such as metals, composites, and plastics.
Enhanced Mechanical Properties: By promoting a more complete reaction between the polyol and isocyanate, BDMAEE contributes to improved tensile strength, elongation, and impact resistance of the adhesive.
Low-Temperature Cure: In some formulations, BDMAEE can facilitate curing at lower temperatures, reducing energy consumption and broadening the application range.

Table 3: Effect of BDMAEE on Polyurethane Adhesive Properties (Example)

Property	Without BDMAEE	With BDMAEE (0.3 wt%)	Improvement (%)	Test Method
Tensile Strength	30 MPa	38 MPa	27%	ASTM D638
Elongation at Break	150%	180%	20%	ASTM D638
T-Peel Strength	80 N/mm	100 N/mm	25%	ASTM D1876

3.3. Specific Aerospace Applications:

BDMAEE-containing adhesives find widespread use in various aerospace applications, including:

Aircraft Structural Bonding: Bonding of fuselage panels, wings, and other structural components.
Composite Bonding: Joining composite materials, such as carbon fiber reinforced polymers (CFRP), in aircraft structures.
Interior Component Assembly: Bonding of interior panels, seats, and other cabin components.
Engine Components: Sealing and bonding of engine parts, where high-temperature resistance is critical.
Rocket and Missile Construction: Bonding of insulation layers and structural elements in rockets and missiles.

4. Advantages of Using BDMAEE in Aerospace Adhesives

High Catalytic Activity: BDMAEE is a highly effective catalyst, requiring only small amounts to achieve significant improvements in cure rate and adhesive properties.
Versatility: BDMAEE can be used in a wide range of adhesive formulations, including epoxy, polyurethane, and other thermosetting systems.
Improved Mechanical Properties: Adhesives containing BDMAEE typically exhibit higher bond strength, tensile strength, elongation, and impact resistance.
Enhanced Thermal Stability: BDMAEE can contribute to improved thermal stability of the adhesive, allowing it to withstand high operating temperatures.
Controlled Cure Rate: The cure rate can be tailored by adjusting the concentration of BDMAEE in the formulation.
Improved Adhesion to Various Substrates: BDMAEE can enhance the adhesion of the adhesive to different materials, including metals, composites, and plastics.
Cost-Effectiveness: Due to its high catalytic activity, only small amounts of BDMAEE are needed, making it a cost-effective additive.

5. Disadvantages and Considerations

Amine Odor: BDMAEE has a characteristic amine odor, which can be unpleasant and may require ventilation during processing.
Potential Toxicity: BDMAEE is a moderate irritant to the skin and eyes, and prolonged exposure may cause sensitization. Proper handling procedures and personal protective equipment should be used.
Influence on Shelf Life: In some formulations, BDMAEE may shorten the shelf life of the adhesive due to its catalytic activity. Proper storage conditions and formulation optimization are necessary to mitigate this issue.
Blooming: Under certain conditions, BDMAEE can migrate to the surface of the cured adhesive, causing a phenomenon known as "blooming." This can affect the appearance and performance of the adhesive.
Sensitivity to Moisture: BDMAEE can react with moisture in the air, leading to a decrease in its catalytic activity. Careful handling and storage in a dry environment are essential.
Regulation: Depending on the region, BDMAEE may be subject to specific regulations regarding its use and disposal.

Table 4: Advantages and Disadvantages of BDMAEE in Aerospace Adhesives

Advantages	Disadvantages
High Catalytic Activity	Amine Odor
Versatility	Potential Toxicity (Irritant, Sensitizer)
Improved Mechanical Properties	Influence on Shelf Life (in some formulations)
Enhanced Thermal Stability	Blooming Potential
Controlled Cure Rate	Sensitivity to Moisture
Improved Adhesion to Various Substrates	Regulation (depending on the region)
Cost-Effectiveness

6. Alternatives and Emerging Trends

While BDMAEE is a widely used catalyst, research efforts are focused on developing alternative catalysts with improved environmental profiles, lower toxicity, and enhanced performance. Some of the emerging trends include:

Bio-based Catalysts: Development of catalysts derived from renewable resources, such as plant oils and sugars, to reduce reliance on petroleum-based chemicals.
Metal-Free Catalysts: Exploration of metal-free catalysts, such as guanidines and amidines, to address concerns about the potential toxicity of metal-containing catalysts.
Blocked Catalysts: Use of blocked catalysts that are inactive at room temperature but become active upon heating or exposure to specific stimuli. This allows for improved control over the curing process and extended shelf life.
Nano-Catalysts: Incorporation of nano-sized catalysts into adhesive formulations to enhance their catalytic activity and improve the dispersion of the catalyst within the adhesive matrix.
Latent Catalysts: Catalysts that are activated by specific triggers, such as UV light or heat, providing precise control over the curing process.

7. Quality Control and Testing

Quality control is essential to ensure the consistent performance of BDMAEE-containing aerospace adhesives. Key quality control measures include:

Raw Material Testing: Verifying the purity and quality of the BDMAEE and other raw materials used in the adhesive formulation.
Viscosity Measurement: Monitoring the viscosity of the adhesive to ensure proper flow and application characteristics.
Gel Time Measurement: Determining the gel time of the adhesive to assess its curing rate.
Bond Strength Testing: Measuring the bond strength of the adhesive using standard test methods (e.g., ASTM D1002, ASTM D1876) to evaluate its adhesion performance.
Thermal Analysis: Performing thermal analysis techniques, such as Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA), to assess the thermal stability and glass transition temperature (Tg) of the cured adhesive.
Environmental Resistance Testing: Evaluating the resistance of the adhesive to various environmental factors, such as temperature, humidity, and chemical exposure.

8. Safety and Handling Precautions

When handling BDMAEE, it is important to follow proper safety precautions to minimize the risk of exposure and potential health hazards.

Personal Protective Equipment (PPE): Wear appropriate PPE, including gloves, safety glasses, and a respirator, to prevent skin and eye contact and inhalation of vapors.
Ventilation: Ensure adequate ventilation in the work area to minimize the concentration of BDMAEE vapors in the air.
Storage: Store BDMAEE in a tightly closed container in a cool, dry, and well-ventilated area. Keep away from heat, sparks, and open flames.
Handling: Avoid contact with skin, eyes, and clothing. Wash thoroughly after handling.
Spills: Clean up spills immediately using appropriate absorbent materials.
Disposal: Dispose of BDMAEE and contaminated materials in accordance with local, state, and federal regulations.
First Aid: In case of skin or eye contact, flush with plenty of water for at least 15 minutes. Seek medical attention if irritation persists. If inhaled, move to fresh air. If swallowed, do not induce vomiting. Seek medical attention immediately.

9. Future Outlook

The demand for high-performance aerospace adhesives is expected to continue to grow in the coming years, driven by the increasing use of composite materials in aircraft construction and the need for more durable and reliable adhesive joints. BDMAEE will likely remain an important component in aerospace adhesive formulations due to its high catalytic activity and versatility. However, research efforts will continue to focus on developing alternative catalysts with improved environmental profiles and enhanced performance characteristics. The future of BDMAEE in aerospace adhesives may involve modifications to its molecular structure or encapsulation techniques to address its limitations, such as its amine odor and potential for blooming. Furthermore, the development of new adhesive formulations that incorporate BDMAEE in combination with other additives and modifiers will be crucial to meeting the evolving demands of the aerospace industry.

10. Conclusion

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE) plays a significant role in high-performance aerospace adhesives as a catalyst that accelerates the curing reaction and enhances the mechanical and thermal properties. Its versatility allows it to be used in both epoxy and polyurethane adhesive systems, contributing to improved bond strength, thermal stability, and adhesion to various substrates. While BDMAEE offers numerous advantages, it also has some drawbacks, such as its amine odor and potential toxicity, which need to be carefully considered. Ongoing research efforts are focused on developing alternative catalysts with improved environmental profiles and enhanced performance. Nevertheless, BDMAEE will likely remain a valuable component in aerospace adhesive formulations for the foreseeable future, provided that proper handling procedures and quality control measures are implemented. The continued innovation in adhesive chemistry and catalyst technology will pave the way for the development of even more advanced aerospace adhesives that meet the stringent requirements of the aerospace industry.

Literature References:

Oertel, G. (Ed.). (1993). Polyurethane handbook. Hanser Gardner Publications.
Ashby, M. F., & Jones, D. (2013). Engineering materials 1: An introduction to properties, applications and design. Butterworth-Heinemann.
Ebnesajjad, S. (2013). Adhesives technology handbook. William Andrew.
Kinloch, A. J. (1983). Adhesion and adhesives: Science and technology. Chapman and Hall.
Pizzi, A., & Mittal, K. L. (Eds.). (2003). Handbook of adhesive technology. Marcel Dekker.
Skeist, I. (Ed.). (1990). Handbook of adhesives. Van Nostrand Reinhold.
Domínguez, J. R., et al. "Influence of amine catalysts on the curing kinetics and properties of epoxy-amine thermosets." Journal of Applied Polymer Science (Year and Volume/Issue details needed).
Wang, L., et al. "Synthesis and application of a novel latent catalyst for epoxy resins." Polymer (Year and Volume/Issue details needed).
Liu, Y., et al. "Bio-based amine catalysts for polyurethane foam production." Industrial Crops and Products (Year and Volume/Issue details needed).
Chen, Z., et al. "Effect of catalyst concentration on the properties of polyurethane adhesives." Journal of Adhesion (Year and Volume/Issue details needed).

Main

Cost-Effective Use of Bis[2-(N,N-Dimethylaminoethyl)] Ether (BDMAEE) in Automotive Interior Trim Production

Abstract: Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE), a tertiary amine catalyst, plays a crucial role in the production of polyurethane (PU) foams used extensively in automotive interior trim. This article comprehensively examines the cost-effective utilization of BDMAEE in this application, covering its chemical properties, mechanism of action, advantages and disadvantages, optimal dosage strategies, potential substitutes, and practical considerations for achieving high-quality and economically viable automotive interior components. Special attention is given to optimizing BDMAEE usage to balance performance attributes like foam density, cell structure, and mechanical strength with cost considerations and volatile organic compound (VOC) emissions.

Contents:

Introduction 🌟
1.1. Automotive Interior Trim: Importance and Materials
1.2. Polyurethane Foams in Automotive Applications
1.3. Role of Amine Catalysts in PU Foam Formation
1.4. Scope of the Article
Bis[2-(N,N-Dimethylaminoethyl)] Ether (BDMAEE): A Comprehensive Overview 🧪
2.1. Chemical Structure and Properties
2.1.1. Chemical Formula and Molecular Weight
2.1.2. Physical Properties (Boiling Point, Density, Solubility, etc.)
2.1.3. Reactivity and Stability
2.2. Synthesis and Production Methods
2.3. Product Parameters and Specifications
Mechanism of Action in Polyurethane Foam Formation 🔬
3.1. Catalysis of the Isocyanate-Polyol Reaction (Gelation)
3.2. Catalysis of the Isocyanate-Water Reaction (Blowing)
3.3. Balancing Gelation and Blowing: The Key to Foam Structure
3.4. Influence of BDMAEE on Foam Morphology and Properties
Advantages and Disadvantages of BDMAEE in Automotive Interior Trim Production 👍 👎
4.1. Advantages
4.1.1. High Catalytic Activity
4.1.2. Control over Foam Structure
4.1.3. Good Compatibility with Polyol Systems
4.1.4. Enhanced Mechanical Properties of Foams
4.2. Disadvantages
4.2.1. VOC Emissions and Odor Concerns
4.2.2. Potential for Discoloration
4.2.3. Dependence on Temperature and Humidity
4.2.4. Cost Considerations
Cost-Effective Dosage Strategies for BDMAEE 💰
5.1. Factors Influencing Optimal Dosage
5.1.1. Polyol Type and Formulation
5.1.2. Isocyanate Index
5.1.3. Water Content
5.1.4. Additive Package (Surfactants, Stabilizers)
5.1.5. Processing Conditions (Temperature, Pressure)
5.2. Dosage Optimization Techniques
5.2.1. Response Surface Methodology (RSM)
5.2.2. Design of Experiments (DOE)
5.2.3. Statistical Analysis of Foam Properties
5.3. Typical Dosage Ranges for Automotive Interior Trim Applications
5.4. Cost Analysis of BDMAEE Usage
Potential Substitutes for BDMAEE 🔄
6.1. Reactive Amine Catalysts
6.2. Delayed-Action Amine Catalysts
6.3. Metal-Based Catalysts (e.g., Tin Catalysts)
6.4. Emerging Catalytic Technologies
6.5. Comparison of Performance, Cost, and Environmental Impact
Practical Considerations for Implementing BDMAEE in Automotive Interior Trim Production ⚙️
7.1. Handling and Storage
7.2. Mixing and Metering
7.3. Processing Parameters Optimization
7.4. Quality Control Procedures
7.5. Regulatory Compliance (VOC Emissions, Safety Standards)
Case Studies and Applications in Automotive Interior Trim 🚗
8.1. Seating
8.2. Headliners
8.3. Door Panels
8.4. Instrument Panels
8.5. Carpets and Floor Mats
Future Trends and Developments 🚀
9.1. Low-VOC and Zero-VOC Catalytic Systems
9.2. Bio-Based Polyols and Catalysts
9.3. Advanced Foam Formulations for Enhanced Performance
9.4. Sustainable Automotive Interior Materials
Conclusion ✅
Literature References 📚

1. Introduction 🌟

1.1. Automotive Interior Trim: Importance and Materials

Automotive interior trim plays a critical role in vehicle aesthetics, comfort, safety, and noise reduction. It encompasses various components such as seats, headliners, door panels, instrument panels, carpets, and floor mats. The materials used in interior trim must meet stringent requirements for durability, flame retardancy, UV resistance, haptics (touch and feel), and low VOC emissions. Traditionally, a variety of materials have been employed, including textiles, plastics, leather, and polyurethane (PU) foams.

1.2. Polyurethane Foams in Automotive Applications

Polyurethane foams are widely used in automotive interior trim due to their excellent cushioning properties, moldability, and cost-effectiveness. They are employed in seating for comfort, headliners for sound absorption and insulation, door panels for aesthetics and impact resistance, and instrument panels for energy absorption in case of accidents. The versatility of PU foams allows for customization of properties to meet specific application requirements.

1.3. Role of Amine Catalysts in PU Foam Formation

The formation of PU foams involves two key reactions: the reaction between isocyanate and polyol (gelation) and the reaction between isocyanate and water (blowing). Amine catalysts are essential for accelerating these reactions and controlling the foam structure. They act as nucleophiles, facilitating the reaction between isocyanate groups and hydroxyl groups (from polyols) or water molecules. The balance between gelation and blowing determines the foam density, cell size, and overall mechanical properties.

1.4. Scope of the Article

This article focuses on the cost-effective use of Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE), a widely used tertiary amine catalyst, in automotive interior trim production. It aims to provide a comprehensive understanding of its properties, mechanism of action, advantages, disadvantages, dosage optimization strategies, potential substitutes, and practical considerations for achieving high-quality and economically viable automotive interior components.

2. Bis[2-(N,N-Dimethylaminoethyl)] Ether (BDMAEE): A Comprehensive Overview 🧪

2.1. Chemical Structure and Properties

BDMAEE is a tertiary amine catalyst with the following characteristics:

2.1.1. Chemical Formula and Molecular Weight

Chemical Formula: C₁₂H₂₈N₂O
Molecular Weight: 216.37 g/mol

2.1.2. Physical Properties (Boiling Point, Density, Solubility, etc.)

Property	Value	Units
Boiling Point	189-190	°C
Density	0.85 (at 25°C)	g/cm³
Flash Point	71	°C
Solubility	Soluble in water, alcohols, and ethers
Vapor Pressure	Low
Appearance	Colorless to light yellow liquid

2.1.3. Reactivity and Stability

BDMAEE is a strong tertiary amine catalyst with high reactivity. It is stable under normal storage conditions but should be protected from moisture and strong oxidizing agents. It can react with isocyanates and acids.

2.2. Synthesis and Production Methods

BDMAEE is typically synthesized by the reaction of dimethylaminoethanol with a suitable etherifying agent, such as a dihaloalkane, under alkaline conditions. The reaction is followed by purification and distillation to obtain the desired product.

2.3. Product Parameters and Specifications

Parameter	Specification	Test Method
Appearance	Clear, colorless liquid	Visual Inspection
Purity	≥ 99.0%	GC
Water Content	≤ 0.1%	Karl Fischer
Refractive Index (20°C)	1.445 – 1.450	Refractometry
Color (APHA)	≤ 20	ASTM D1209

3. Mechanism of Action in Polyurethane Foam Formation 🔬

3.1. Catalysis of the Isocyanate-Polyol Reaction (Gelation)

BDMAEE, as a tertiary amine, acts as a nucleophilic catalyst in the reaction between isocyanate and polyol. It enhances the reactivity of the hydroxyl group of the polyol by forming a complex, making it more susceptible to attack by the isocyanate group. This leads to the formation of a urethane linkage, which contributes to the gelation process and the building of the polymer network.

3.2. Catalysis of the Isocyanate-Water Reaction (Blowing)

BDMAEE also catalyzes the reaction between isocyanate and water. This reaction generates carbon dioxide (CO₂), which acts as the blowing agent, creating the cellular structure of the foam. The amine catalyst promotes the formation of carbamic acid, which then decomposes to form CO₂ and an amine. The amine is then free to catalyze further reactions.

3.3. Balancing Gelation and Blowing: The Key to Foam Structure

The relative rates of the gelation and blowing reactions are crucial for controlling the foam structure. If gelation proceeds too quickly, the foam may collapse before sufficient CO₂ is generated. Conversely, if blowing proceeds too quickly, the foam may have large, open cells and poor mechanical properties. BDMAEE, being a strong gelling catalyst, needs to be carefully balanced with other catalysts, such as blowing catalysts, to achieve the desired foam characteristics.

3.4. Influence of BDMAEE on Foam Morphology and Properties

The dosage of BDMAEE significantly affects the foam morphology and properties. Higher dosages generally lead to faster reaction rates, finer cell structures, and increased foam hardness. However, excessive use can also result in shrinkage, collapse, and increased VOC emissions.

4. Advantages and Disadvantages of BDMAEE in Automotive Interior Trim Production 👍 👎

4.1. Advantages

4.1.1. High Catalytic Activity: BDMAEE is a highly effective catalyst for both gelation and blowing reactions, leading to rapid foam formation and reduced cycle times.

4.1.2. Control over Foam Structure: By carefully adjusting the dosage of BDMAEE, manufacturers can control the cell size, cell distribution, and overall foam structure, tailoring the properties to specific application requirements.

4.1.3. Good Compatibility with Polyol Systems: BDMAEE is generally compatible with a wide range of polyol systems commonly used in automotive interior trim production.

4.1.4. Enhanced Mechanical Properties of Foams: BDMAEE can contribute to improved mechanical properties of the foams, such as tensile strength, tear strength, and elongation at break, by promoting a more uniform and robust polymer network.

4.2. Disadvantages

4.2.1. VOC Emissions and Odor Concerns: BDMAEE is a volatile organic compound (VOC) and can contribute to odor problems in automotive interiors. This is a significant concern due to increasingly stringent regulations on VOC emissions.

4.2.2. Potential for Discoloration: Under certain conditions, BDMAEE can contribute to discoloration of the foam, particularly when exposed to UV light or heat.

4.2.3. Dependence on Temperature and Humidity: The catalytic activity of BDMAEE can be affected by temperature and humidity fluctuations, requiring careful control of processing conditions.

4.2.4. Cost Considerations: BDMAEE adds to the overall cost of the foam formulation. Therefore, optimizing its usage and exploring potential substitutes is crucial for cost-effectiveness.

5. Cost-Effective Dosage Strategies for BDMAEE 💰

5.1. Factors Influencing Optimal Dosage

The optimal dosage of BDMAEE in automotive interior trim production depends on several factors:

5.1.1. Polyol Type and Formulation: Different polyols have varying reactivities and require different catalyst levels. Polyether polyols, polyester polyols, and bio-based polyols each require specific adjustments to the BDMAEE dosage.

5.1.2. Isocyanate Index: The isocyanate index (the ratio of isocyanate to polyol) affects the reaction stoichiometry and thus the catalyst requirement.

5.1.3. Water Content: The amount of water used as a blowing agent influences the CO₂ generation and requires adjustment of the blowing catalyst (which BDMAEE partially functions as).

5.1.4. Additive Package (Surfactants, Stabilizers): Surfactants and stabilizers can interact with the catalyst, affecting its activity. Careful selection and optimization of the additive package are essential.

5.1.5. Processing Conditions (Temperature, Pressure): Temperature and pressure influence the reaction rates and the solubility of gases, impacting the optimal catalyst dosage.

5.2. Dosage Optimization Techniques

Several techniques can be used to optimize the dosage of BDMAEE:

5.2.1. Response Surface Methodology (RSM): RSM is a statistical technique that uses a series of designed experiments to model the relationship between the input variables (e.g., catalyst dosage, polyol type) and the output variables (e.g., foam density, cell size, mechanical properties). This allows for the identification of the optimal dosage that maximizes desired properties while minimizing cost.

5.2.2. Design of Experiments (DOE): DOE is a systematic approach to planning experiments to efficiently gather data and identify the key factors influencing the foam properties. Fractional factorial designs and central composite designs are commonly used.

5.2.3. Statistical Analysis of Foam Properties: Statistical analysis of the foam properties (e.g., density, cell size, mechanical strength) is crucial for determining the significance of the catalyst dosage and identifying the optimal operating conditions.

5.3. Typical Dosage Ranges for Automotive Interior Trim Applications

The typical dosage range for BDMAEE in automotive interior trim applications is generally between 0.1 and 1.0 phr (parts per hundred parts of polyol). However, the specific dosage will depend on the factors listed above.

5.4. Cost Analysis of BDMAEE Usage

A cost analysis should be performed to determine the economic impact of BDMAEE usage. This analysis should consider the cost of the catalyst, the impact on foam production efficiency, and the cost of addressing VOC emissions.

Table 1: Example of Cost Analysis of BDMAEE Usage

Parameter	Unit	Value
BDMAEE Dosage	phr	0.5
Polyol Cost	$/kg	2.0
BDMAEE Cost	$/kg	10.0
Foam Density	kg/m³	30
VOC Emission Level	ppm	50
Cost per unit foam	$/kg	Calculated from input values
VOC emission cost (if applicable)	$/kg	Calculated from emission level and regulation cost
Total Cost per unit foam	$/kg	Sum of material cost and VOC cost

6. Potential Substitutes for BDMAEE 🔄

Due to increasing concerns about VOC emissions, several substitutes for BDMAEE are being explored:

6.1. Reactive Amine Catalysts: Reactive amine catalysts are designed to become chemically incorporated into the polyurethane polymer network during the foaming process, reducing VOC emissions. Examples include catalysts containing hydroxyl or isocyanate-reactive groups.

6.2. Delayed-Action Amine Catalysts: These catalysts are designed to be less active at lower temperatures and become more active as the temperature increases during the foaming process. This can help to control the reaction rate and improve foam quality.

6.3. Metal-Based Catalysts (e.g., Tin Catalysts): Tin catalysts, such as dibutyltin dilaurate (DBTDL), can be used as alternatives to amine catalysts. However, tin catalysts have their own environmental and toxicity concerns.

6.4. Emerging Catalytic Technologies: New catalytic technologies, such as enzymatic catalysis and metal-organic frameworks (MOFs), are being explored as potential alternatives to traditional amine catalysts.

6.5. Comparison of Performance, Cost, and Environmental Impact

Catalyst Type	Performance	Cost	VOC Emissions	Environmental Impact
BDMAEE	High Activity	Moderate	High	Moderate
Reactive Amine Catalysts	Moderate to High	High	Low	Moderate
Delayed-Action Amines	Moderate	Moderate to High	Moderate	Moderate
Metal-Based Catalysts	High Activity	Low to Moderate	Low	High
Emerging Technologies	Variable	High	Low	Potentially Low

7. Practical Considerations for Implementing BDMAEE in Automotive Interior Trim Production ⚙️

7.1. Handling and Storage

BDMAEE should be handled with care, avoiding contact with skin and eyes. It should be stored in a cool, dry, and well-ventilated area, away from heat, sparks, and open flames.

7.2. Mixing and Metering

Accurate mixing and metering of BDMAEE are crucial for achieving consistent foam properties. Automated metering systems are recommended for large-scale production.

7.3. Processing Parameters Optimization

Optimizing processing parameters, such as temperature, pressure, and mixing speed, is essential for maximizing the effectiveness of BDMAEE and achieving the desired foam characteristics.

7.4. Quality Control Procedures

Rigorous quality control procedures should be implemented to ensure that the foam meets the required specifications for density, cell size, mechanical properties, and VOC emissions.

7.5. Regulatory Compliance (VOC Emissions, Safety Standards)

Automotive interior trim manufacturers must comply with all relevant regulations regarding VOC emissions and safety standards. This may require the use of emission control technologies and the implementation of safety protocols.

8. Case Studies and Applications in Automotive Interior Trim 🚗

8.1. Seating: BDMAEE is used in the production of flexible PU foams for seat cushions and backrests, providing comfort and support.

8.2. Headliners: BDMAEE is used in the production of semi-rigid PU foams for headliners, providing sound absorption and insulation.

8.3. Door Panels: BDMAEE is used in the production of semi-rigid PU foams for door panels, providing aesthetics and impact resistance.

8.4. Instrument Panels: BDMAEE is used in the production of integral skin PU foams for instrument panels, providing energy absorption in case of accidents.

8.5. Carpets and Floor Mats: BDMAEE is used in the production of flexible PU foams for carpet backing and floor mats, providing cushioning and durability.

9. Future Trends and Developments 🚀

9.1. Low-VOC and Zero-VOC Catalytic Systems: Research is ongoing to develop low-VOC and zero-VOC catalytic systems for PU foam production.

9.2. Bio-Based Polyols and Catalysts: The use of bio-based polyols and catalysts is increasing as manufacturers seek more sustainable materials.

9.3. Advanced Foam Formulations for Enhanced Performance: Advanced foam formulations are being developed to enhance performance characteristics such as flame retardancy, UV resistance, and mechanical properties.

9.4. Sustainable Automotive Interior Materials: The automotive industry is increasingly focused on using sustainable materials in interior trim, including recycled plastics and bio-based polymers.

10. Conclusion ✅

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE) remains a vital catalyst in the production of polyurethane foams for automotive interior trim due to its high catalytic activity and ability to control foam structure. However, its use requires careful consideration of cost, VOC emissions, and other environmental factors. By optimizing dosage strategies, exploring potential substitutes, and implementing practical considerations for handling and processing, manufacturers can achieve cost-effective and high-quality automotive interior components that meet increasingly stringent performance and sustainability requirements. The future of BDMAEE in this application lies in the development of low-VOC alternatives and the adoption of more sustainable materials and processes.

11. Literature References 📚

Oertel, G. (Ed.). (1994). Polyurethane Handbook. Hanser Gardner Publications.
Rand, L., & Chatgilialoglu, C. (2003). Photooxidation of Polymers. Chemistry and Physics. Academic Press.
Woods, G. (1990). The ICI Polyurethanes Book. John Wiley & Sons.
Szycher, M. (2012). Szycher’s Handbook of Polyurethanes, Second Edition. CRC Press.
Ulrich, H. (1996). Introduction to Industrial Polymers. Hanser Gardner Publications.
Prociak, A., Ryszkowska, J., & Uram, Ł. (2016). Polyurethane Foams: Properties, Modifications and Applications. Smithers Rapra.
Hepburn, C. (1991). Polyurethane Elastomers. Elsevier Science Publishers.
Ashida, K. (2006). Polyurethane and Related Foams: Chemistry and Technology. CRC Press.

Main

Bis[2-(N,N-Dimethylaminoethyl)] Ether: A Catalyst for Accelerated Curing in Industrial Coatings

Abstract:

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE), also known as Jeffcat ZF-20 or Dabco BL-19, is a tertiary amine catalyst widely employed in the formulation of polyurethane, epoxy, and other thermosetting industrial coatings. Its primary function is to accelerate the curing process, leading to enhanced productivity, improved coating properties, and reduced energy consumption. This article delves into the chemical properties, mechanism of action, applications, advantages, disadvantages, safety considerations, and future trends of BDMAEE in the context of industrial coatings, highlighting its critical role in modern coating technology.

Table of Contents:

Introduction
Chemical Properties
- 2.1 Chemical Formula and Structure
- 2.2 Physical Properties
- 2.3 Reactivity
Mechanism of Action in Coating Systems
- 3.1 Polyurethane Coatings
- 3.2 Epoxy Coatings
- 3.3 Other Thermosetting Coatings
Applications in Industrial Coatings
- 4.1 Automotive Coatings
- 4.2 Coil Coatings
- 4.3 Wood Coatings
- 4.4 Marine Coatings
- 4.5 Protective Coatings
Advantages of Using BDMAEE
- 5.1 Accelerated Curing Time
- 5.2 Improved Throughput
- 5.3 Enhanced Coating Properties
- 5.4 Lower Energy Consumption
Disadvantages and Limitations
- 6.1 Volatility and Odor
- 6.2 Potential for Yellowing
- 6.3 Compatibility Issues
- 6.4 Over-Catalyzation
Safety Considerations
- 7.1 Toxicity
- 7.2 Handling and Storage
- 7.3 Environmental Impact
Formulation Considerations
- 8.1 Dosage
- 8.2 Compatibility with other Additives
- 8.3 Influence of Temperature and Humidity
Alternative Catalysts
- 9.1 Other Tertiary Amines
- 9.2 Metal Catalysts
- 9.3 Amine Blocking Agents
Future Trends and Developments
Conclusion
References

1. Introduction

Industrial coatings play a crucial role in protecting and enhancing the performance of a wide range of materials, from automobiles and buildings to appliances and machinery. The curing process, during which the liquid coating transforms into a solid film, is a critical step in achieving the desired protective and aesthetic properties. The duration of this curing process significantly impacts production efficiency and overall cost-effectiveness. Catalysts are often employed to accelerate the curing reaction, thereby reducing processing time and improving throughput. Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE) has emerged as a prominent catalyst in various industrial coating formulations due to its effectiveness in promoting rapid curing, particularly in polyurethane and epoxy systems. This article provides a comprehensive overview of BDMAEE, exploring its chemical properties, mechanism of action, applications, advantages, disadvantages, safety considerations, and future trends in the industrial coatings sector.

2. Chemical Properties

2.1 Chemical Formula and Structure

BDMAEE is an organic compound belonging to the class of tertiary amines. Its chemical formula is C₁₀H₂₄N₂O, and its structural formula can be represented as:

(CH₃)₂N-CH₂-CH₂-O-CH₂-CH₂-N(CH₃)₂

The molecule contains two dimethylaminoethyl groups linked by an ether linkage. This structure contributes to its strong catalytic activity, particularly in reactions involving isocyanates and epoxides.

2.2 Physical Properties

The physical properties of BDMAEE are summarized in the following table:

Property	Value	Unit
Molecular Weight	172.31	g/mol
Appearance	Colorless to slightly yellow liquid	–
Boiling Point	189-192	°C
Flash Point	60-70	°C
Density	0.84-0.86	g/cm³
Viscosity	2-3	cP (at 25°C)
Refractive Index	1.44-1.45	–
Solubility	Soluble in water and organic solvents	–

2.3 Reactivity

BDMAEE is a highly reactive tertiary amine. The nitrogen atoms in the molecule possess lone pairs of electrons, making it a strong nucleophile and a good base. This reactivity enables it to catalyze various chemical reactions, including:

Polyurethane formation: BDMAEE accelerates the reaction between isocyanates and alcohols (polyols) to form polyurethanes.
Epoxy curing: BDMAEE can catalyze the ring-opening polymerization of epoxy resins with curing agents (hardeners) like amines or anhydrides.
Other reactions: BDMAEE can also catalyze other reactions, such as transesterification and Michael addition.

3. Mechanism of Action in Coating Systems

The catalytic activity of BDMAEE in coating systems stems from its ability to facilitate the reactions between the key components, leading to the formation of the crosslinked polymer network that constitutes the cured coating.

3.1 Polyurethane Coatings

In polyurethane coatings, BDMAEE primarily acts as a catalyst for two crucial reactions:

The reaction between isocyanate and polyol: BDMAEE promotes the nucleophilic attack of the hydroxyl group of the polyol on the electrophilic carbon atom of the isocyanate group, forming a urethane linkage. The proposed mechanism involves the amine nitrogen coordinating with the hydroxyl group, increasing its nucleophilicity.
The isocyanate trimerization reaction: BDMAEE can also catalyze the trimerization of isocyanates, leading to the formation of isocyanurate rings. These rings contribute to the crosslink density and thermal stability of the polyurethane coating.

The relative rates of these two reactions are influenced by the concentration of BDMAEE, the reaction temperature, and the specific isocyanate and polyol being used. Optimizing these parameters is crucial for achieving the desired coating properties.

3.2 Epoxy Coatings

In epoxy coatings, BDMAEE functions as an accelerator for the reaction between the epoxy resin and the curing agent (hardener), typically an amine or an anhydride.

Amine-cured epoxy systems: BDMAEE enhances the nucleophilic attack of the amine curing agent on the epoxy ring, leading to ring-opening polymerization and crosslinking. The amine group of the curing agent abstracts a proton from the BDMAEE, creating a more reactive nucleophile.
Anhydride-cured epoxy systems: While less common, BDMAEE can also promote the reaction between epoxy resins and anhydrides. In this case, BDMAEE facilitates the ring-opening of the anhydride by the hydroxyl groups generated during the epoxy-anhydride reaction.

The choice of curing agent and the concentration of BDMAEE are critical factors in determining the curing rate and final properties of the epoxy coating.

3.3 Other Thermosetting Coatings

BDMAEE can also be used as a catalyst in other thermosetting coating systems, such as those based on acrylic resins, alkyd resins, and unsaturated polyesters. Its catalytic activity in these systems depends on the specific chemistry involved and the presence of reactive functional groups that can interact with the amine nitrogen of BDMAEE.

4. Applications in Industrial Coatings

BDMAEE finds widespread application in various industrial coating sectors due to its effectiveness in accelerating curing and improving coating performance.

4.1 Automotive Coatings

In automotive coatings, BDMAEE is used in both primer and topcoat formulations, particularly in polyurethane-based systems. It helps to reduce the curing time of the coatings, allowing for faster production cycles in automotive assembly plants. The use of BDMAEE also contributes to improved coating hardness, scratch resistance, and gloss.

4.2 Coil Coatings

Coil coatings are applied to continuous metal strips that are subsequently formed into various products, such as appliance panels, roofing sheets, and automotive parts. BDMAEE is used in coil coating formulations to ensure rapid curing during the high-speed coating process. The accelerated curing enables high production rates and minimizes the risk of coating defects.

4.3 Wood Coatings

Wood coatings are used to protect and enhance the aesthetic appeal of wood furniture, flooring, and other wood products. BDMAEE is employed in polyurethane wood coatings to shorten the curing time and improve the coating’s resistance to abrasion, chemicals, and moisture.

4.4 Marine Coatings

Marine coatings are designed to protect ships, offshore platforms, and other marine structures from corrosion and fouling. BDMAEE is used in marine coatings based on epoxy and polyurethane resins to accelerate curing and provide durable protection against harsh marine environments.

4.5 Protective Coatings

Protective coatings are applied to a wide range of industrial equipment and infrastructure to prevent corrosion, abrasion, and chemical attack. BDMAEE is used in these coatings to enhance the curing speed and provide long-lasting protection in demanding environments. Examples include coatings for pipelines, storage tanks, and bridges.

Coating Type	Application Area	Resin System	Benefits from BDMAEE Use
Automotive Coating	Car bodies, parts	Polyurethane, Acrylic	Faster curing, improved hardness & scratch resistance, enhanced gloss
Coil Coating	Metal sheets (appliances, roofing)	Polyurethane, Polyester	Rapid curing at high speeds, minimized defects, increased production efficiency
Wood Coating	Furniture, flooring	Polyurethane	Shortened curing time, improved abrasion & chemical resistance, enhanced moisture resistance
Marine Coating	Ships, offshore platforms	Epoxy, Polyurethane	Accelerated curing, durable protection against corrosion & fouling in harsh marine environments
Protective Coating	Pipelines, tanks, bridges	Epoxy, Polyurethane	Enhanced curing speed, long-lasting protection in demanding industrial environments

5. Advantages of Using BDMAEE

The use of BDMAEE in industrial coating formulations offers several significant advantages:

5.1 Accelerated Curing Time

The primary advantage of BDMAEE is its ability to significantly reduce the curing time of coatings. This acceleration is crucial for improving production efficiency and minimizing downtime.

5.2 Improved Throughput

By reducing the curing time, BDMAEE enables higher throughput in coating operations. This increased throughput translates into higher productivity and reduced manufacturing costs.

5.3 Enhanced Coating Properties

In many cases, the use of BDMAEE can also lead to improved coating properties, such as hardness, gloss, chemical resistance, and adhesion. These improvements are often attributed to the more complete and uniform curing achieved with the catalyst.

5.4 Lower Energy Consumption

In some coating processes, the curing step requires elevated temperatures. By accelerating the curing process, BDMAEE can reduce the energy required to heat the coatings, leading to lower energy consumption and reduced environmental impact.

6. Disadvantages and Limitations

Despite its numerous advantages, BDMAEE also has some disadvantages and limitations that need to be considered when formulating industrial coatings:

6.1 Volatility and Odor

BDMAEE is a volatile compound with a characteristic amine odor. This odor can be unpleasant and may require the use of ventilation systems to maintain acceptable air quality in the workplace. The volatility of BDMAEE can also lead to its gradual loss from the coating formulation, potentially affecting the long-term performance of the coating.

6.2 Potential for Yellowing

In some cases, the use of BDMAEE can contribute to yellowing of the coating, particularly upon exposure to UV light. This yellowing can be undesirable, especially in coatings that are intended to be clear or white.

6.3 Compatibility Issues

BDMAEE may not be compatible with all coating formulations. It can react with certain components or interfere with other additives, leading to undesirable effects such as gelling, precipitation, or reduced coating performance.

6.4 Over-Catalyzation

Using too much BDMAEE can lead to over-catalyzation, which can result in rapid and uncontrolled curing, leading to defects such as blistering, cracking, or poor adhesion.

7. Safety Considerations

BDMAEE is a chemical substance that requires careful handling and storage to ensure the safety of workers and the environment.

7.1 Toxicity

BDMAEE is considered to be moderately toxic. It can cause skin and eye irritation upon contact. Inhalation of vapors can cause respiratory irritation. Ingestion can cause gastrointestinal distress. Appropriate personal protective equipment (PPE), such as gloves, goggles, and respirators, should be used when handling BDMAEE.

7.2 Handling and Storage

BDMAEE should be handled in a well-ventilated area. It should be stored in tightly closed containers in a cool, dry place away from heat, sparks, and open flames. Contact with incompatible materials, such as strong acids and oxidizing agents, should be avoided.

7.3 Environmental Impact

BDMAEE can be harmful to aquatic organisms. Spills should be contained and cleaned up immediately. Waste containing BDMAEE should be disposed of in accordance with local regulations.

8. Formulation Considerations

Effective use of BDMAEE in coating formulations requires careful consideration of several factors:

8.1 Dosage

The optimal dosage of BDMAEE depends on the specific coating formulation, the desired curing rate, and the desired coating properties. Typically, BDMAEE is used at concentrations ranging from 0.1% to 2% by weight of the resin solids. Excessive use can lead to the disadvantages mentioned earlier.

8.2 Compatibility with other Additives

It is essential to ensure that BDMAEE is compatible with all other additives in the coating formulation, such as pigments, fillers, stabilizers, and flow control agents. Incompatibility can lead to phase separation, sedimentation, or other undesirable effects.

8.3 Influence of Temperature and Humidity

The curing rate of coatings catalyzed by BDMAEE is influenced by temperature and humidity. Higher temperatures generally accelerate the curing process, while high humidity can sometimes inhibit the curing reaction, particularly in polyurethane systems.

9. Alternative Catalysts

While BDMAEE is a widely used catalyst, alternative catalysts are available for industrial coating applications.

9.1 Other Tertiary Amines

Other tertiary amines, such as triethylamine (TEA), triethylenediamine (TEDA), and N,N-dimethylcyclohexylamine (DMCHA), can also be used as catalysts in coating formulations. However, these amines may have different catalytic activities and may affect the coating properties differently.

9.2 Metal Catalysts

Metal catalysts, such as tin compounds (e.g., dibutyltin dilaurate, DBTDL), zinc compounds, and bismuth compounds, are also commonly used in polyurethane coatings. Metal catalysts are generally more active than tertiary amines, but they can also be more toxic and can contribute to yellowing.

9.3 Amine Blocking Agents

Amine blocking agents can be used to temporarily deactivate BDMAEE or other amine catalysts, allowing for longer pot life of the coating formulation. The blocking agent is typically a compound that reacts with the amine nitrogen, rendering it unreactive. The blocking agent can be removed by heating or by reaction with another component of the coating formulation, thereby reactivating the amine catalyst.

Catalyst Type	Examples	Advantages	Disadvantages
Tertiary Amines	TEA, TEDA, DMCHA	Lower toxicity compared to metal catalysts, readily available	Lower catalytic activity compared to metal catalysts, potential for amine odor
Metal Catalysts	DBTDL, Zinc compounds, Bismuth compounds	High catalytic activity, can lead to fast curing	Higher toxicity, potential for yellowing, can affect coating stability
Amine Blocking Agents	Ketimines, Aldimines	Extended pot life, controlled curing	Requires a deblocking step, can affect coating properties if not completely removed

10. Future Trends and Developments

The future of BDMAEE in industrial coatings is likely to be shaped by several trends and developments:

Development of Low-Odor BDMAEE Derivatives: Research efforts are focused on developing BDMAEE derivatives with lower volatility and reduced odor, addressing a major drawback of the current product.
Combination with other Catalysts: Synergistic catalyst systems combining BDMAEE with other catalysts, such as metal catalysts or enzymes, are being explored to achieve optimal curing performance and coating properties.
Microencapsulation of BDMAEE: Encapsulating BDMAEE in microcapsules can provide controlled release of the catalyst, allowing for improved control over the curing process and extended pot life of the coating formulation.
Bio-based Alternatives: There is growing interest in developing bio-based alternatives to BDMAEE, derived from renewable resources. This would contribute to more sustainable coating formulations.
Further Optimization of Dosage & Compatibility: Research continues to optimize the dosage of BDMAEE for specific applications and to improve its compatibility with a wider range of coating components.

11. Conclusion

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE) remains a vital catalyst in the industrial coatings industry, particularly in polyurethane and epoxy systems. Its ability to accelerate curing, improve throughput, and enhance coating properties makes it a valuable tool for formulators. While its volatility, odor, and potential for yellowing pose challenges, ongoing research and development efforts are focused on mitigating these drawbacks and exploring new applications. The future of BDMAEE in industrial coatings is likely to involve the development of lower-odor derivatives, synergistic catalyst systems, microencapsulation techniques, and bio-based alternatives, contributing to more sustainable and high-performance coating solutions.

12. References

Wicks, D. A., Jones, F. N., & Pappas, S. P. (2007). Organic Coatings: Science and Technology. John Wiley & Sons.
Lambourne, R., & Strivens, T. A. (1999). Paint and Surface Coatings: Theory and Practice. Woodhead Publishing.
Ashby, J., & Goode, R. J. (2001). High Solids Alkyd Resins. John Wiley & Sons.
Ulrich, H. (1996). Introduction to Industrial Polymers. Hanser Gardner Publications.
Römpp Online, Georg Thieme Verlag. (Chemical database; search for "Bis(2-dimethylaminoethyl) ether").
Database of REACH registered substances, European Chemicals Agency. (Search for "Bis(2-dimethylaminoethyl) ether").
Randall, D., & Lee, S. (2002). The Polyurethanes Book. John Wiley & Sons.
Primeaux, D. J., & Lindsly, C. (1996). US Patent 5508344. Method of reducing odor in amine catalysts.
Blank, W.J. (1982). Progress in Organic Coatings, 10(3), 255-271. The Chemistry of Amine Catalyzed Epoxy Resins.
Bauer, D. R., & Dickie, R. A. (1980). Journal of Coatings Technology, 52(660), 63-67. Amine-epoxy cure kinetics.

Main

Bis[2-(N,N-Dimethylaminoethyl)] Ether (BDMAEE) in Sustainable Wood Composite Bonding Solutions

Introduction

The wood composite industry is facing increasing pressure to adopt more sustainable practices. Traditional formaldehyde-based resins, while providing excellent bonding properties, release harmful volatile organic compounds (VOCs) during manufacturing and use, contributing to air pollution and health concerns. This has spurred research into alternative, bio-based adhesives and innovative bonding technologies. Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE), also known as 2,2′-Dimorpholinyldiethyl Ether, is emerging as a promising component in sustainable wood composite bonding solutions due to its catalytic properties and potential to reduce or eliminate formaldehyde emissions. This article provides a comprehensive overview of BDMAEE, exploring its properties, mechanisms of action, applications in wood composite bonding, and its role in promoting sustainable manufacturing practices.

1. Overview of BDMAEE

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE) is a tertiary amine catalyst commonly used in polyurethane (PU) foam production. Its molecular structure features two tertiary amine groups connected by an ether linkage. This structure contributes to its high catalytic activity and its ability to accelerate various chemical reactions relevant to wood composite bonding.

1.1 Nomenclature and Identification

Property	Value
IUPAC Name	2,2′-Dimorpholinyldiethyl Ether
CAS Registry Number	6425-39-4
Molecular Formula	C₁₂H₂₆N₂O
Molecular Weight	214.35 g/mol
Other Names	Bis(2-dimethylaminoethyl) ether; BDMAEE

1.2 Physical and Chemical Properties

Property	Value	Source
Appearance	Colorless to slightly yellow liquid	Supplier Data Sheet
Density	0.85 g/cm³ at 20°C	Supplier Data Sheet
Boiling Point	189-192°C	Supplier Data Sheet
Flash Point	68°C	Supplier Data Sheet
Vapor Pressure	Low	Supplier Data Sheet
Solubility in Water	Soluble	Supplier Data Sheet
pH (1% aqueous solution)	Alkaline	Supplier Data Sheet

1.3 Production Methods

BDMAEE is typically synthesized through the ethoxylation of dimethylamine followed by etherification. The specific manufacturing process is often proprietary but generally involves reacting dimethylamine with ethylene oxide to form 2-(dimethylamino)ethanol, which is then etherified to produce BDMAEE.

2. Mechanism of Action in Wood Composite Bonding

BDMAEE’s role in wood composite bonding stems primarily from its catalytic activity in various chemical reactions, particularly those involving crosslinking and curing of adhesives.

2.1 Catalysis of Polyurethane Formation

BDMAEE is a well-established catalyst for polyurethane (PU) foam production. In wood composite applications involving PU adhesives, BDMAEE accelerates the reaction between isocyanates and polyols, leading to the formation of urethane linkages. This enhanced reaction rate results in faster curing times and improved bond strength.

The mechanism involves BDMAEE acting as a nucleophile, abstracting a proton from the hydroxyl group of the polyol. This activated polyol then attacks the isocyanate group, forming the urethane linkage. BDMAEE is regenerated in the process, allowing it to catalyze further reactions.

2.2 Promotion of Crosslinking in Bio-Based Resins

Beyond PU adhesives, BDMAEE can also promote crosslinking in other bio-based resins, such as those derived from lignin, tannins, or carbohydrates. The mechanism varies depending on the specific resin system, but generally involves BDMAEE facilitating reactions that lead to the formation of covalent bonds between resin molecules, thereby increasing the network density and improving the mechanical properties of the adhesive.

For example, in lignin-based adhesives, BDMAEE can catalyze the reaction of lignin with crosslinking agents such as glyoxal or epichlorohydrin, promoting the formation of a rigid, three-dimensional network.

2.3 pH Modification and Its Impact on Bonding

BDMAEE is an alkaline compound. Its addition to adhesive formulations can modify the pH of the mixture. This pH adjustment can be crucial for the activation of certain crosslinking agents or for improving the compatibility of different components within the adhesive system.

For instance, in some tannin-based adhesives, a slightly alkaline pH is required for the tannins to react effectively with formaldehyde or other crosslinking agents. BDMAEE can provide the necessary alkalinity without contributing to formaldehyde emissions.

3. Applications in Wood Composite Bonding

BDMAEE is finding increasing use in various wood composite bonding applications, particularly where sustainability and reduced formaldehyde emissions are desired.

3.1 Particleboard and Fiberboard Manufacturing

Traditional particleboard and fiberboard production relies heavily on formaldehyde-based resins, such as urea-formaldehyde (UF) and phenol-formaldehyde (PF). BDMAEE can be used as a catalyst or co-catalyst in alternative resin systems to reduce or eliminate formaldehyde emissions.

Formaldehyde-Free Resins: BDMAEE can catalyze the crosslinking of bio-based resins, such as those derived from soy protein, starch, or lignin, to produce formaldehyde-free particleboard and fiberboard.
Low-Formaldehyde Resins: In modified UF or PF resin systems, BDMAEE can be used to reduce the amount of formaldehyde required while maintaining acceptable bonding performance. This can be achieved by promoting more efficient crosslinking of the resin.

3.2 Plywood Production

Plywood manufacturing also traditionally utilizes formaldehyde-based resins. BDMAEE can be employed in similar ways as in particleboard and fiberboard production to promote the use of more sustainable adhesives.

Tannin-Formaldehyde Resins: BDMAEE can be used to adjust the pH of tannin-formaldehyde resin systems, optimizing the reaction between tannins and formaldehyde and reducing the amount of free formaldehyde in the final product.
Bio-Based Plywood Adhesives: BDMAEE can catalyze the crosslinking of bio-based polymers, such as modified starch or soy protein, to create formaldehyde-free plywood adhesives.

3.3 Laminated Veneer Lumber (LVL) and Glued Laminated Timber (Glulam)

LVL and Glulam are engineered wood products that require high-strength adhesives to bond multiple layers of wood veneer or timber. BDMAEE can be used in both PU and bio-based adhesive systems for LVL and Glulam production.

Polyurethane Adhesives for LVL and Glulam: BDMAEE accelerates the curing of PU adhesives, leading to faster production cycles and improved bond strength in LVL and Glulam products.
Lignin-Based Adhesives for LVL: BDMAEE can be used in conjunction with other crosslinking agents to create high-performance lignin-based adhesives for LVL production.

3.4 Wood Adhesives for General Applications

Beyond composite manufacturing, BDMAEE can also be incorporated into wood adhesives for general applications, such as furniture assembly and woodworking.

Improved Bonding of Difficult-to-Bond Wood Species: BDMAEE can enhance the bonding of wood species that are typically difficult to bond due to their high oil or resin content.
Faster Curing Times: The catalytic activity of BDMAEE can significantly reduce the curing time of wood adhesives, improving productivity.

4. Advantages of Using BDMAEE in Wood Composite Bonding

The use of BDMAEE in wood composite bonding offers several advantages over traditional approaches.

4.1 Reduced Formaldehyde Emissions

The primary advantage is the potential to reduce or eliminate formaldehyde emissions from wood composite products. By enabling the use of formaldehyde-free or low-formaldehyde resins, BDMAEE contributes to improved indoor air quality and reduced health risks.

4.2 Enhanced Bond Strength

BDMAEE can enhance the bond strength of adhesives by promoting more efficient crosslinking and improved adhesion to the wood substrate.

4.3 Faster Curing Times

The catalytic activity of BDMAEE can significantly reduce the curing time of adhesives, leading to faster production cycles and increased throughput.

4.4 Improved Sustainability

By enabling the use of bio-based resins, BDMAEE contributes to the overall sustainability of wood composite products, reducing reliance on fossil fuels and promoting the use of renewable resources.

4.5 Versatility

BDMAEE can be used in a variety of adhesive systems, including PU, lignin-based, tannin-based, and starch-based adhesives, making it a versatile tool for wood composite bonding.

5. Potential Drawbacks and Mitigation Strategies

While BDMAEE offers numerous advantages, there are also potential drawbacks that need to be considered.

5.1 Potential Toxicity and Handling Precautions

BDMAEE is a tertiary amine and can be irritating to the skin, eyes, and respiratory system. Proper handling precautions, including the use of personal protective equipment (PPE), such as gloves, safety glasses, and respirators, are essential.

5.2 Influence on Adhesive Viscosity and Rheology

The addition of BDMAEE can affect the viscosity and rheology of adhesive formulations. Careful formulation adjustments may be necessary to ensure that the adhesive has the desired application properties.

5.3 Potential for Yellowing of Adhesive

In some cases, BDMAEE can contribute to the yellowing of adhesive formulations, particularly when exposed to UV light. The use of UV stabilizers or alternative catalysts may be necessary to mitigate this effect.

5.4 Odor

BDMAEE possesses a characteristic amine odor, which some may find objectionable. Proper ventilation during manufacturing and application is recommended.

Mitigation Strategies:

Proper Ventilation: Ensure adequate ventilation in manufacturing facilities to minimize exposure to BDMAEE vapors.
Personal Protective Equipment (PPE): Require workers to wear appropriate PPE, including gloves, safety glasses, and respirators.
Formulation Optimization: Carefully optimize adhesive formulations to minimize the amount of BDMAEE required and to address any potential issues with viscosity, rheology, or color.
Alternative Catalysts: Explore the use of alternative catalysts that may offer similar performance with fewer drawbacks.
UV Stabilizers: Incorporate UV stabilizers into adhesive formulations to prevent yellowing.

6. Regulatory Considerations

The use of BDMAEE in wood composite bonding is subject to various regulatory requirements.

6.1 VOC Emissions Regulations

Wood composite products are often subject to regulations limiting VOC emissions, including formaldehyde. The use of BDMAEE to reduce or eliminate formaldehyde emissions can help manufacturers comply with these regulations.

6.2 Chemical Substance Regulations (e.g., REACH, TSCA)

BDMAEE is subject to regulations governing the manufacture, import, and use of chemical substances, such as the European Union’s REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulation and the United States’ TSCA (Toxic Substances Control Act). Manufacturers and users must ensure that they comply with all applicable requirements.

6.3 Occupational Safety and Health Regulations

Occupational safety and health regulations govern the handling and use of chemicals in the workplace. Employers must provide workers with appropriate training and PPE to minimize the risk of exposure to BDMAEE.

7. Market Trends and Future Outlook

The market for sustainable wood composite bonding solutions is growing rapidly, driven by increasing demand for environmentally friendly products and stricter regulations on formaldehyde emissions. BDMAEE is well-positioned to play a significant role in this market.

7.1 Increasing Demand for Sustainable Wood Composites

Consumers and businesses are increasingly seeking out sustainable wood composite products that are made with environmentally friendly materials and processes. This trend is driving demand for adhesives that reduce or eliminate formaldehyde emissions.

7.2 Stricter Regulations on Formaldehyde Emissions

Government regulations on formaldehyde emissions are becoming increasingly stringent in many countries. This is forcing manufacturers to adopt alternative resin systems and bonding technologies that comply with these regulations.

7.3 Growth of Bio-Based Adhesives

The market for bio-based adhesives is growing rapidly as manufacturers seek to reduce their reliance on fossil fuels and promote the use of renewable resources. BDMAEE can play a key role in enabling the use of bio-based resins in wood composite bonding.

7.4 Innovation in Adhesive Technologies

Ongoing research and development efforts are focused on developing new and improved adhesive technologies that are both sustainable and high-performing. BDMAEE is likely to be a key component in many of these new technologies.

Future Outlook:

The future outlook for BDMAEE in wood composite bonding is positive. As demand for sustainable wood composite products continues to grow, and as regulations on formaldehyde emissions become more stringent, the use of BDMAEE is likely to increase. Further research and development efforts will likely focus on optimizing the use of BDMAEE in combination with bio-based resins and on developing new adhesive technologies that are both sustainable and high-performing.

8. Comparative Analysis with Alternative Catalysts

While BDMAEE is a valuable catalyst, it’s important to consider alternatives and their respective strengths and weaknesses.

Catalyst	Advantages	Disadvantages	Suitable Applications
BDMAEE	High catalytic activity, versatile, effective in various resin systems.	Potential for irritation, amine odor, possible yellowing.	Particleboard, fiberboard, plywood, LVL, Glulam, general wood adhesives.
Dabco (Triethylenediamine)	High catalytic activity, well-established, often used in PU foams.	Strong amine odor, potential for discoloration.	Polyurethane adhesives for wood bonding.
DMAPA (Dimethylaminopropylamine)	Good reactivity, lower molecular weight.	Strong amine odor, potential for irritation.	Wood adhesives requiring rapid curing.
Organic Acids (e.g., Citric Acid)	Less toxic, environmentally friendly.	Lower catalytic activity, may require higher concentrations.	Bio-based adhesives where toxicity is a major concern.
Metal Catalysts (e.g., Tin compounds)	High catalytic activity, effective in some PU systems.	Potential toxicity, environmental concerns, regulatory restrictions.	Specialized PU adhesives for high-performance applications.

9. Conclusion

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE) is a valuable tool for promoting sustainability in the wood composite bonding industry. Its catalytic properties enable the use of formaldehyde-free or low-formaldehyde resins, leading to improved indoor air quality and reduced health risks. While potential drawbacks such as toxicity and odor need to be carefully managed through proper handling and formulation optimization, the benefits of BDMAEE in terms of enhanced bond strength, faster curing times, and improved sustainability make it a promising component in the future of wood composite bonding. As demand for sustainable wood products continues to grow, BDMAEE is poised to play a significant role in shaping the industry’s transition towards more environmentally friendly practices.

Literature Sources:

[1] Ashori, A. (2008). Wood–plastic composites as promising green-building materials. Bioresource Technology, 99(11), 4661-4667.

[2] Dunky, M. (1998). Urea-formaldehyde (UF) adhesives for wood. International Journal of Adhesion and Adhesives, 18(2), 95-106.

[3] Frihart, C. R., & Birkeland, M. (2015). Adhesives used for wood and wood products. Forest Products Laboratory, USDA Forest Service, General Technical Report FPL-GTR-238.

[4] Pizzi, A. (2003). Recent developments in bio-based adhesives for wood bonding: Opportunities and issues. Journal of Adhesion, 79(6), 477-492.

[5] Sellers, T. (2001). Wood adhesives: Chemistry and technology. CRC press.

[6] Umemura, K., Inoue, A., & Kawai, S. (2006). Development of formaldehyde-free particleboards bonded with powdered tannin adhesives. Journal of Wood Science, 52(4), 321-326.

[7] European Chemicals Agency (ECHA). REACH Database. [Note: Specific REACH registration information should be referenced here, but external links are prohibited]

[8] United States Environmental Protection Agency (EPA). Toxic Substances Control Act (TSCA). [Note: Specific TSCA information should be referenced here, but external links are prohibited]

[9] Supplier Safety Data Sheets (SDS) for BDMAEE. [Note: Referencing specific SDS sheets by manufacturer is acceptable, but external links are prohibited]

Main

Bis[2-(N,N-Dimethylaminoethyl)] Ether (BDMAEE) in Low-Odor Epoxy Resin Formulations: A Comprehensive Overview

Introduction

Epoxy resins are widely used thermosetting polymers renowned for their excellent adhesive properties, chemical resistance, and mechanical strength. They find applications in diverse industries, including coatings, adhesives, composites, and electronics. However, a significant drawback of many epoxy resin formulations is the presence of volatile organic compounds (VOCs) and unpleasant odors, often stemming from the curing agents or accelerators used. These odors can pose health risks and environmental concerns, limiting their applicability in enclosed spaces and sensitive environments.

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE), a tertiary amine catalyst, presents a compelling alternative for formulating low-odor epoxy resin systems. This article provides a comprehensive overview of BDMAEE, focusing on its properties, mechanism of action, advantages in reducing odor, applications, handling precautions, and future trends.

1. Chemical Identity and Physical Properties

BDMAEE is a tertiary amine catalyst belonging to the ether amine family. Its chemical structure, properties, and parameters are crucial for understanding its functionality in epoxy resin formulations.

Chemical Name: Bis[2-(N,N-Dimethylaminoethyl)] Ether
Synonyms: Dimorpholinodiethyl ether, DMDEE, JEFFCAT ZF-10, DABCO DME
CAS Registry Number: 3033-62-3
Chemical Formula: C₁₂H₂₆N₂O
Molecular Weight: 214.35 g/mol

Table 1: Physical Properties of BDMAEE

Property	Value	Unit	Reference
Appearance	Colorless to Pale Yellow Liquid	–	[1]
Density (20°C)	0.85 – 0.86	g/cm³	[2]
Boiling Point	189-190	°C	[3]
Flash Point (Closed Cup)	71-74	°C	[4]
Viscosity (20°C)	2.5 – 3.5	cP	[2]
Refractive Index (n20/D)	1.440 – 1.445	–	[1]
Solubility (Water, 20°C)	Soluble	–	Internal Data
Amine Value	520-530	mg KOH/g	[2]

2. Mechanism of Action as an Epoxy Curing Accelerator

BDMAEE functions as a highly efficient tertiary amine catalyst in epoxy resin curing reactions. Its mechanism involves two primary pathways:

Anion Generation: BDMAEE facilitates the ring-opening polymerization of epoxy resins by abstracting a proton from hydroxyl groups present in the resin or a co-reactant (e.g., alcohol). This generates an alkoxide anion, a powerful nucleophile that attacks the epoxide ring, initiating chain propagation.
```
R-OH + BDMAEE <=> R-O- + BDMAEE-H+
```
Coordination Catalysis: BDMAEE can coordinate with the epoxide oxygen, activating the epoxide ring towards nucleophilic attack. This coordination weakens the C-O bond in the epoxide, making it more susceptible to reaction with nucleophiles such as hydroxyl groups or amines.
```
Epoxide + BDMAEE <=> [Epoxide---BDMAEE] (activated complex)
```

The synergistic effect of these two pathways makes BDMAEE a potent accelerator, enabling rapid curing even at relatively low concentrations. The ether linkage in BDMAEE enhances its flexibility and availability of the amine groups, contributing to its high catalytic activity.

3. Advantages of BDMAEE in Low-Odor Formulations

The primary advantage of BDMAEE lies in its ability to produce low-odor epoxy resin formulations compared to traditional amine curing agents, particularly those with lower molecular weights or higher volatility.

Reduced Volatility: BDMAEE has a relatively high molecular weight and lower vapor pressure compared to many conventional amine curing agents like diethylenetriamine (DETA) or triethylenetetramine (TETA). This lower volatility translates to reduced emissions of odorous amines during and after the curing process.
Improved Amine Blushing Resistance: Amine blushing is a phenomenon observed with amine-cured epoxy resins, especially under humid conditions. It involves the reaction of amine curing agents with atmospheric carbon dioxide and moisture, forming carbamates that appear as a white, hazy film on the surface. BDMAEE-cured systems exhibit improved resistance to amine blushing due to the catalyst’s lower reactivity towards atmospheric CO₂ and its efficient incorporation into the polymer network.
Faster Cure Rates: BDMAEE’s high catalytic activity allows for faster cure rates at lower concentrations. This reduces the overall exposure time to uncured resin and minimizes the potential for odor generation.
Enhanced Chemical Resistance: Properly formulated BDMAEE-cured epoxy resins exhibit excellent chemical resistance, similar to those cured with traditional amine curing agents. This is crucial for applications where the cured material will be exposed to harsh chemicals or solvents.

Table 2: Comparison of Odor and Volatility of Different Curing Agents

Curing Agent	Molecular Weight (g/mol)	Boiling Point (°C)	Odor Level (Subjective)	Volatility (Relative)
Diethylenetriamine (DETA)	103.17	207	Strong, Pungent	High
Triethylenetetramine (TETA)	146.23	277	Strong, Ammoniacal	Medium
Isophorone Diamine (IPDA)	170.30	247	Moderate, Amine-like	Medium
Bis[2-(N,N-Dimethylaminoethyl)] Ether (BDMAEE)	214.35	189-190	Mild, Amine-like	Low

Note: Odor Level is subjective and varies based on individual sensitivity. Volatility is a relative comparison.

4. Applications of BDMAEE in Epoxy Resin Formulations

BDMAEE finds applications in a wide array of epoxy resin formulations where low odor and rapid cure are desirable.

Coatings:
- Floor Coatings: BDMAEE is used in self-leveling epoxy floor coatings for residential, commercial, and industrial applications. The low-odor characteristic makes it suitable for use in occupied spaces.
- Protective Coatings: Used in protective coatings for metal structures, pipelines, and chemical storage tanks, offering excellent chemical resistance and corrosion protection with minimal odor.
- Waterborne Epoxy Coatings: BDMAEE can be incorporated into waterborne epoxy systems as a co-catalyst to enhance cure speed and film properties.
Adhesives:
- Structural Adhesives: Employed in structural adhesives for bonding metals, plastics, and composites in automotive, aerospace, and construction industries. The low-odor property is beneficial in enclosed manufacturing environments.
- Electronics Adhesives: Used in electronics assembly for bonding components to printed circuit boards (PCBs), providing good electrical insulation and mechanical strength.
Composites:
- Fiber-Reinforced Polymers (FRPs): Utilized in the manufacturing of FRP composites for aerospace, automotive, and marine applications. The faster cure rates facilitated by BDMAEE can improve production efficiency.
- Tooling Resins: Used in tooling resins for creating molds and patterns, offering good dimensional stability and heat resistance.
Encapsulation Compounds:
- Electronics Encapsulation: Used as a catalyst in epoxy formulations for encapsulating electronic components, providing protection against moisture, dust, and mechanical stress. The low-odor characteristic is important for worker safety and comfort in electronics manufacturing facilities.

5. Formulation Considerations and Optimization

Optimizing epoxy resin formulations with BDMAEE requires careful consideration of various factors, including resin type, hardener type, stoichiometry, and other additives.

Resin Selection: BDMAEE is compatible with a wide range of epoxy resins, including bisphenol-A epoxy resins, bisphenol-F epoxy resins, epoxy novolacs, and cycloaliphatic epoxy resins. The choice of resin depends on the specific application requirements, such as viscosity, glass transition temperature (Tg), and chemical resistance.
Hardener Selection: While BDMAEE primarily acts as an accelerator, it is typically used in conjunction with a primary amine or anhydride hardener. The type and amount of hardener significantly influence the cure rate, mechanical properties, and chemical resistance of the cured epoxy. Aliphatic amines, cycloaliphatic amines, and polyamidoamines are commonly used hardeners.
Stoichiometry: The stoichiometry of the epoxy resin and hardener should be carefully controlled to ensure complete curing and optimal properties. An excess or deficiency of either component can lead to incomplete curing, reduced mechanical strength, and increased odor.
Concentration of BDMAEE: The optimal concentration of BDMAEE typically ranges from 0.1% to 5% by weight of the resin-hardener mixture. The exact concentration depends on the desired cure rate and the reactivity of the resin and hardener. Higher concentrations of BDMAEE can accelerate the cure but may also reduce the pot life of the mixture.
Additives: Various additives can be incorporated into epoxy resin formulations to modify their properties, such as fillers, pigments, plasticizers, and flame retardants. Fillers can improve mechanical strength, reduce shrinkage, and lower cost. Pigments provide color and opacity. Plasticizers enhance flexibility. Flame retardants improve fire resistance.

Table 3: Example Epoxy Formulation with BDMAEE

Component	Weight (%)	Function
Bisphenol-A Epoxy Resin	50	Resin
Polyamidoamine Hardener	45	Hardener
BDMAEE	2.0	Accelerator
Fumed Silica	3.0	Thixotrope

6. Handling Precautions and Safety Information

BDMAEE, like other chemical compounds, should be handled with care. Following proper safety procedures is essential to minimize potential health risks.

Skin and Eye Contact: BDMAEE can cause skin and eye irritation. Wear appropriate personal protective equipment (PPE), such as gloves, safety glasses, and protective clothing, when handling the material. In case of skin contact, wash thoroughly with soap and water. In case of eye contact, flush with plenty of water for at least 15 minutes and seek medical attention.
Inhalation: Inhalation of BDMAEE vapors can cause respiratory irritation. Ensure adequate ventilation when working with the material. Use a respirator if necessary.
Ingestion: Do not ingest BDMAEE. If ingested, seek medical attention immediately.
Storage: Store BDMAEE in a cool, dry, and well-ventilated area away from incompatible materials, such as strong acids and oxidizing agents. Keep containers tightly closed to prevent moisture contamination.
Disposal: Dispose of BDMAEE and contaminated materials in accordance with local, state, and federal regulations.

7. Advantages and Disadvantages of Using BDMAEE

Table 4: Advantages and Disadvantages of BDMAEE

Feature	Advantages	Disadvantages
Odor	Lower odor compared to traditional amine curing agents	Still possesses a mild amine-like odor, may not be completely odorless.
Cure Rate	Faster cure rates at lower concentrations	May reduce pot life of the mixture.
Volatility	Lower volatility, reduced emissions
Blushing	Improved amine blushing resistance
Properties	Excellent chemical resistance and mechanical properties
Cost		Can be more expensive than some traditional amine curing agents.
Handling		Requires proper handling and safety precautions.

8. Alternatives to BDMAEE

While BDMAEE offers significant advantages in low-odor epoxy formulations, other catalysts and curing agents can be considered as alternatives, depending on the specific application requirements and cost constraints.

Modified Amines: Modified amines, such as Mannich bases and amidoamines, can provide lower odor and improved compatibility with epoxy resins.
Tertiary Amine Blends: Blends of tertiary amines with different functionalities can be used to optimize cure rate and odor profile.
Latent Catalysts: Latent catalysts, such as boron trifluoride complexes, require activation by heat or other stimuli, providing long pot life and controlled curing.
Anhydride Curing Agents: Anhydride curing agents offer good chemical resistance and electrical properties but typically require higher curing temperatures.

9. Market Trends and Future Outlook

The demand for low-VOC and low-odor epoxy resin formulations is steadily increasing due to growing environmental awareness and stricter regulations. This trend is driving the adoption of BDMAEE and other similar catalysts in various industries. Future research and development efforts are likely to focus on:

Developing novel catalysts with even lower odor and improved performance.
Optimizing epoxy resin formulations for specific applications.
Exploring new applications for BDMAEE in emerging fields, such as bio-based epoxy resins and sustainable coatings.
Improving the cost-effectiveness of BDMAEE to make it more competitive with traditional curing agents.

10. Conclusion

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE) is a valuable tertiary amine catalyst for formulating low-odor epoxy resin systems. Its lower volatility, improved amine blushing resistance, and faster cure rates make it an attractive alternative to traditional amine curing agents in various applications, including coatings, adhesives, composites, and electronics. Careful formulation considerations, proper handling precautions, and ongoing research and development efforts will further enhance the performance and broaden the applicability of BDMAEE in the future. As environmental regulations become more stringent and consumer demand for low-odor products increases, BDMAEE is poised to play an increasingly important role in the epoxy resin industry. 🚀

References

[1] Sigma-Aldrich. (n.d.). Bis[2-(N,N-dimethylaminoethyl)] ether. Product Information.

[2] Air Products and Chemicals, Inc. (n.d.). DABCO® DME catalyst. Product Data Sheet.

[3] PubChem. (n.d.). Bis(2-(dimethylamino)ethyl) ether. National Center for Biotechnology Information.

[4] BASF. (n.d.). Lupragen® N 205. Product Information.

Main

Applications of Bis[2-(N,N-Dimethylaminoethyl)] Ether in Epoxy Resin Curing Systems for Industrial Adhesives

Abstract: Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE), also known as 2,2′-Dimorpholinyldiethyl Ether, is a tertiary amine catalyst widely employed in the curing of epoxy resins, particularly within the realm of industrial adhesives. This article provides a comprehensive overview of BDMAEE’s application in epoxy resin curing systems, focusing on its mechanism of action, advantages, limitations, impact on adhesive properties, and formulation considerations. The content is structured to reflect the comprehensive nature of entries found in encyclopedic resources, emphasizing factual accuracy, standardized terminology, and rigorous referencing.

1. Introduction

Epoxy resins are a class of thermosetting polymers renowned for their exceptional adhesive strength, chemical resistance, mechanical properties, and electrical insulation capabilities. These properties make them ideal for a wide array of industrial adhesive applications, ranging from structural bonding in aerospace and automotive industries to electronic component encapsulation and protective coatings. The curing process, or crosslinking, of epoxy resins is crucial for developing these desirable characteristics. This process involves the reaction of the epoxy groups with a curing agent (also known as a hardener) to form a rigid, three-dimensional network.

Tertiary amines are frequently used as catalysts in epoxy resin curing systems. They function by accelerating the reaction between the epoxy resin and the curing agent, typically an anhydride or an amine. Among these tertiary amine catalysts, Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE) stands out due to its effectiveness and specific characteristics that influence the final properties of the cured adhesive. BDMAEE offers a balanced profile of reactivity, handling, and performance, making it a valuable component in many industrial adhesive formulations.

2. Chemical Structure and Properties of BDMAEE

BDMAEE is a tertiary amine ether with the following chemical structure:

(CH₃)₂NCH₂CH₂OCH₂CH₂N(CH₃)₂

Table 1: Physical and Chemical Properties of BDMAEE

Property	Value	Source
Molecular Formula	C₁₀H₂₄N₂O	Supplier MSDS
Molecular Weight	188.31 g/mol	Supplier MSDS
CAS Registry Number	3033-62-3	Chemical Databases
Appearance	Colorless to light yellow liquid	Supplier MSDS
Density (at 20°C)	0.85 – 0.86 g/cm³	Supplier MSDS
Boiling Point	189-192 °C	Supplier MSDS
Flash Point	68-74 °C	Supplier MSDS
Viscosity (at 25°C)	1.8 – 2.2 mPa·s	Supplier MSDS
Water Solubility	Miscible	Supplier MSDS
Amine Value	~595 mg KOH/g	Supplier MSDS

Source: Typically derived from Material Safety Data Sheets (MSDS) provided by chemical suppliers and publicly available chemical databases.

3. Mechanism of Action in Epoxy Curing

BDMAEE acts as a catalyst in the epoxy curing process through a nucleophilic mechanism. It primarily promotes the homopolymerization of epoxy resin or accelerates the reaction between epoxy resin and hardeners, such as anhydrides or amines. The mechanism can be described in the following steps:

Initiation: The nitrogen atom in BDMAEE, possessing a lone pair of electrons, acts as a nucleophile and attacks the oxirane ring (epoxy group) of the epoxy resin. This ring-opening process creates a zwitterionic intermediate.
Propagation: The zwitterionic intermediate can then react with another epoxy molecule, propagating the chain. Alternatively, it can react with a protic species present in the system, such as water or an alcohol impurity, to generate a hydroxyl group and regenerate the tertiary amine catalyst.
Crosslinking (with Anhydrides): When used with anhydride curing agents, BDMAEE facilitates the reaction between the hydroxyl groups generated during epoxy ring opening and the anhydride functionality. This reaction forms ester linkages, contributing to the crosslinked network.
Crosslinking (with Amines): With amine curing agents, BDMAEE accelerates the reaction between the amine hydrogen and the epoxy group, forming a carbon-nitrogen bond and opening the epoxy ring.

The ether linkage in BDMAEE contributes to its solubility and compatibility within epoxy resin formulations. The two tertiary amine groups enhance its catalytic activity compared to mono-amine catalysts.

4. Advantages of Using BDMAEE in Epoxy Adhesive Systems

BDMAEE offers several advantages as a catalyst in epoxy resin curing systems for industrial adhesives:

Enhanced Cure Rate: BDMAEE significantly accelerates the curing process at room temperature or elevated temperatures, reducing cycle times and improving production efficiency.
Lower Curing Temperatures: The use of BDMAEE allows for curing at lower temperatures, which can be beneficial when dealing with heat-sensitive substrates or when energy consumption is a concern.
Improved Adhesive Strength: Properly formulated systems using BDMAEE can exhibit excellent adhesive strength, both in terms of shear strength and peel strength.
Good Chemical Resistance: Cured epoxy adhesives containing BDMAEE often demonstrate good resistance to various chemicals, including solvents, acids, and bases.
Low Volatility: Compared to some other tertiary amine catalysts, BDMAEE has a relatively low volatility, reducing the risk of air pollution and improving workplace safety.
Good Compatibility: The ether linkage in the molecule enhances its compatibility with a wide range of epoxy resins and other additives.
Controllable Reactivity: The catalytic activity of BDMAEE can be adjusted by varying its concentration in the formulation, allowing for fine-tuning of the curing process.

5. Limitations and Considerations

Despite its advantages, BDMAEE also has some limitations that need to be considered:

Potential for Yellowing: In some formulations, particularly those exposed to UV light or high temperatures, BDMAEE can contribute to yellowing of the cured adhesive. This can be mitigated through the use of UV stabilizers or alternative catalysts.
Moisture Sensitivity: BDMAEE is hygroscopic and can absorb moisture from the atmosphere. Moisture can react with the epoxy resin and negatively impact the curing process and the final properties of the adhesive. Proper storage and handling are essential.
Toxicity and Irritation: Like many tertiary amines, BDMAEE can be irritating to the skin, eyes, and respiratory system. Appropriate personal protective equipment (PPE) should be used when handling this chemical.
Influence on Glass Transition Temperature (Tg): The use of BDMAEE can affect the glass transition temperature (Tg) of the cured epoxy adhesive. The Tg is an important indicator of the thermal performance of the adhesive. Careful formulation is needed to achieve the desired Tg for specific applications.
Blooming: In some cases, BDMAEE can migrate to the surface of the cured adhesive, resulting in a phenomenon known as blooming. This can affect the appearance and performance of the adhesive.

6. Impact on Adhesive Properties

The incorporation of BDMAEE into epoxy resin curing systems significantly influences the properties of the resulting adhesive. The extent of this influence depends on factors such as the concentration of BDMAEE, the type of epoxy resin and hardener used, and the presence of other additives.

Table 2: Impact of BDMAEE on Adhesive Properties

Property	Impact	Considerations
Cure Speed	Increases cure speed significantly at room temperature and elevated temperatures.	Over-catalyzation can lead to rapid curing and reduced pot life. Optimize concentration based on the desired application.
Adhesive Strength	Generally improves adhesive strength (shear, peel) due to enhanced crosslinking.	Excessive BDMAEE can lead to brittleness and reduced impact resistance. Balance the concentration for optimal strength and toughness.
Chemical Resistance	Can improve chemical resistance, especially to solvents and acids.	The specific chemical resistance depends on the formulation and the type of epoxy resin and hardener used.
Thermal Properties (Tg)	Can influence the glass transition temperature (Tg) of the cured adhesive. May increase or decrease Tg depending on the formulation.	Target Tg should be considered based on the application’s temperature requirements.
Viscosity	May slightly reduce the viscosity of the epoxy resin mixture, improving handling and application.	The effect on viscosity is relatively small compared to the effect of other additives, such as diluents.
Color Stability	Can contribute to yellowing, especially upon exposure to UV light or high temperatures.	Use UV stabilizers or alternative catalysts to mitigate yellowing.
Pot Life	Decreases pot life due to accelerated curing.	Adjust the concentration of BDMAEE to achieve the desired pot life. Consider using latent catalysts for longer pot life applications.

7. Formulation Considerations

When formulating epoxy adhesives with BDMAEE, several factors should be considered to achieve the desired performance:

Epoxy Resin Selection: The type of epoxy resin used will significantly impact the properties of the cured adhesive. Common epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, and epoxy novolacs.
Hardener Selection: The choice of hardener is critical. Common hardeners include amines (e.g., aliphatic amines, cycloaliphatic amines, aromatic amines), anhydrides (e.g., phthalic anhydride, methyltetrahydrophthalic anhydride), and polyamides. The hardener type will influence the curing speed, mechanical properties, and chemical resistance of the adhesive.
BDMAEE Concentration: The concentration of BDMAEE should be optimized based on the desired cure speed, pot life, and final properties of the adhesive. Typical concentrations range from 0.1% to 5% by weight of the epoxy resin.
Other Additives: Other additives can be incorporated into the formulation to further enhance the properties of the adhesive. These additives may include:
- Fillers: To improve mechanical properties, reduce shrinkage, or lower cost (e.g., silica, calcium carbonate, talc).
- Diluents: To reduce viscosity and improve handling (e.g., reactive diluents, non-reactive diluents).
- Tougheners: To improve impact resistance and crack propagation resistance (e.g., liquid rubbers, core-shell rubbers).
- UV Stabilizers: To protect the adhesive from degradation due to UV light.
- Adhesion Promoters: To improve adhesion to specific substrates (e.g., silanes).
Mixing and Application: Proper mixing of the epoxy resin, hardener, BDMAEE, and other additives is essential for achieving uniform curing and optimal performance. The application method should also be considered.

Table 3: Formulation Guidelines for BDMAEE-Cured Epoxy Adhesives

Component	Typical Range (% by weight)	Function	Considerations
Epoxy Resin	40-80	Provides the base polymer matrix for the adhesive.	Choose epoxy resin based on desired properties (e.g., viscosity, Tg, chemical resistance).
Hardener	15-40	Reacts with the epoxy resin to form the crosslinked network.	Select hardener based on desired cure speed, mechanical properties, and chemical resistance.
BDMAEE	0.1-5	Catalyzes the curing reaction between the epoxy resin and the hardener.	Optimize concentration for desired cure speed and pot life.
Fillers	0-50	Improve mechanical properties, reduce shrinkage, lower cost.	Select filler based on desired properties and compatibility with the epoxy resin system.
Diluents	0-20	Reduce viscosity, improve handling.	Choose diluent based on compatibility and effect on final properties. Use reactive diluents when possible.
Tougheners	0-15	Improve impact resistance and crack propagation resistance.	Select toughener based on compatibility and desired level of toughness.
UV Stabilizers	0-2	Protect adhesive from degradation due to UV light.	Use when the adhesive will be exposed to UV light.
Adhesion Promoters	0-2	Improve adhesion to specific substrates.	Select adhesion promoter based on the substrate being bonded.

8. Applications in Industrial Adhesives

BDMAEE is utilized in various industrial adhesive applications, including:

Structural Adhesives: Used in aerospace, automotive, and construction industries for bonding structural components. Examples include bonding composite materials, metals, and plastics.
Electronic Adhesives: Used for encapsulating electronic components, bonding surface mount devices, and creating thermally conductive adhesives.
Coating Adhesives: Used in protective coatings for metal, concrete, and other surfaces, providing corrosion resistance and chemical resistance.
General Purpose Adhesives: Used for a wide range of bonding applications in various industries.

9. Safety and Handling

BDMAEE is a chemical that should be handled with care. The following safety precautions should be observed:

Personal Protective Equipment (PPE): Wear appropriate PPE, including gloves, safety glasses, and a respirator, when handling BDMAEE.
Ventilation: Use adequate ventilation to prevent inhalation of BDMAEE vapors.
Storage: Store BDMAEE in a cool, dry, and well-ventilated area. Keep away from heat, sparks, and open flames.
First Aid: In case of contact with skin or eyes, flush immediately with plenty of water. Seek medical attention if irritation persists. If inhaled, move to fresh air. If swallowed, do not induce vomiting. Seek medical attention immediately.

10. Future Trends

Research and development efforts are focused on:

Developing modified BDMAEE derivatives: To improve specific properties such as color stability, pot life, or reactivity.
Exploring the use of BDMAEE in combination with other catalysts: To achieve synergistic effects and optimize curing performance.
Investigating the use of BDMAEE in new epoxy resin systems: Such as bio-based epoxy resins and high-performance epoxy resins.
Developing encapsulated or latent BDMAEE catalysts: For improved pot life and controlled curing.

11. Conclusion

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE) is a versatile and effective tertiary amine catalyst for epoxy resin curing systems used in industrial adhesives. Its ability to accelerate curing at lower temperatures, enhance adhesive strength, and provide good chemical resistance makes it a valuable component in many adhesive formulations. However, its potential for yellowing, moisture sensitivity, and toxicity should be carefully considered. By understanding the mechanism of action, advantages, limitations, and formulation considerations associated with BDMAEE, adhesive formulators can effectively utilize this catalyst to create high-performance adhesives for a wide range of industrial applications. Careful formulation and handling are essential to maximize the benefits of BDMAEE while minimizing potential risks.

12. References

Ellis, B. (1993). Chemistry and Technology of Epoxy Resins. Springer Science & Business Media.
Goodman, S. H. (1986). Handbook of Thermoset Plastics. Noyes Publications.
Lee, H., & Neville, K. (1967). Handbook of Epoxy Resins. McGraw-Hill.
May, C. A. (1988). Epoxy Resins: Chemistry and Technology. Marcel Dekker.
Skeist, I. (1958). Epoxy Resins. Reinhold Publishing Corporation.
Supplier Material Safety Data Sheets (MSDS) for BDMAEE.
Various patents and journal articles related to epoxy resin curing and tertiary amine catalysts.

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Main

Enhancing Crosslink Density with Bis[2-(N,N-Dimethylaminoethyl)] Ether in UV-Stable Coatings

Introduction

Ultraviolet (UV)-curable coatings have gained significant traction across various industries due to their rapid curing speed, low volatile organic compound (VOC) emissions, and excellent mechanical and chemical resistance. However, achieving optimal UV stability in these coatings remains a crucial challenge. Degradation due to prolonged UV exposure can manifest as yellowing, cracking, loss of gloss, and diminished protective performance. Enhancing the crosslink density of the coating network is a well-established strategy to improve its UV resistance by reducing polymer chain mobility and minimizing the diffusion of degradation products.

Bis[2-(N,N-Dimethylaminoethyl)] ether, often abbreviated as BDMAEE or Jeffcat ZF-10, is a tertiary amine catalyst widely used in polyurethane (PU) foam production. However, its potential as a crosslinking promoter in UV-curable coatings, especially those requiring enhanced UV stability, is increasingly recognized. This article delves into the mechanisms by which BDMAEE enhances crosslink density, its application in various UV-curable systems, and its impact on the overall performance, particularly UV stability, of the resulting coatings.

1. Bis[2-(N,N-Dimethylaminoethyl)] Ether: Properties and Mechanism

1.1. Chemical Structure and Properties

BDMAEE is a tertiary amine compound with the chemical formula C₁₂H₂₈N₂O. Its structure consists of an ether linkage connecting two dimethylaminoethyl groups. Key properties of BDMAEE are summarized in Table 1.

Table 1: Properties of Bis[2-(N,N-Dimethylaminoethyl)] Ether

Property	Value (Typical)	Unit	Reference
Molecular Weight	204.36	g/mol	[1]
Appearance	Clear, colorless liquid	–	[1]
Density (25°C)	0.84 – 0.85	g/cm³	[1]
Boiling Point	189-192	°C	[1]
Flash Point	66	°C	[1]
Vapor Pressure	< 1	mmHg (20°C)	[1]
Viscosity (25°C)	2.5-3.5	cP	[1]
Amine Value	545-555	mg KOH/g	[1]

Reference: [1] Supplier Technical Data Sheet (e.g., Huntsman, Air Products) – Note: specific values can vary slightly between suppliers.

1.2. Mechanism of Action in UV-Curable Coatings

BDMAEE acts as a catalyst to promote crosslinking reactions in UV-curable systems, particularly those based on acrylates and epoxies. Its mechanism of action can be described as follows:

Base Catalysis: BDMAEE, being a tertiary amine, acts as a nucleophilic base. It abstracts a proton from acidic groups present in the resin system or generated during the UV curing process (e.g., from carboxylic acid groups or hydroxyl groups). This proton abstraction increases the reactivity of other functional groups, such as acrylates or epoxies, towards crosslinking.
Promotion of Isocyanate Reactions (in PU Systems): In UV-curable polyurethane (PU) coatings, BDMAEE accelerates the reaction between isocyanates and hydroxyl-containing components. This is a critical step in the formation of the urethane linkages that define the PU network. The nitrogen atom in BDMAEE coordinates with the isocyanate group, increasing its electrophilicity and making it more susceptible to nucleophilic attack by the hydroxyl group.
Chain Transfer Agent (in certain acrylate systems): In some acrylate-based UV-curable systems, BDMAEE can act as a chain transfer agent, influencing the polymerization process. While not directly involved in crosslinking, its presence can lead to a more controlled polymerization and potentially higher crosslink density by affecting the chain length and branching of the polymer network.
Reaction with Photoinitiators: BDMAEE can interact with certain photoinitiators, particularly those that generate acidic byproducts upon UV exposure. This interaction can neutralize the acidic byproducts and prevent them from inhibiting the polymerization process. This indirect effect can also contribute to a higher overall crosslink density.

The specific mechanism by which BDMAEE influences crosslinking depends on the specific resin system and photoinitiator used. However, the overall effect is typically an increase in the rate and extent of crosslinking, leading to a denser and more robust coating network.

2. Application of BDMAEE in UV-Curable Coatings

BDMAEE finds application in various UV-curable coating formulations, including:

UV-Curable Polyurethane (PU) Coatings: These coatings are known for their excellent flexibility, abrasion resistance, and chemical resistance. BDMAEE plays a crucial role in accelerating the urethane reaction, ensuring rapid curing and high crosslink density.
UV-Curable Acrylate Coatings: Acrylate-based coatings are widely used in applications requiring high hardness, scratch resistance, and gloss. BDMAEE can enhance the crosslinking of acrylates, leading to improved mechanical properties and solvent resistance.
UV-Curable Epoxy Coatings: Epoxy-based coatings are valued for their excellent adhesion, chemical resistance, and electrical insulation properties. BDMAEE can promote the crosslinking of epoxies with hardeners, resulting in a denser and more durable coating.

Table 2: Typical Applications of BDMAEE in UV-Curable Coatings

Coating Type	Application Areas	Benefits of using BDMAEE
UV-Curable PU Coatings	Wood coatings, automotive coatings, textile coatings	Faster curing, improved flexibility, enhanced chemical resistance, increased crosslink density
UV-Curable Acrylate Coatings	Graphic arts, overprint varnishes, plastic coatings	Higher hardness, improved scratch resistance, better solvent resistance, increased crosslink density
UV-Curable Epoxy Coatings	Electronics, industrial coatings, floor coatings	Enhanced adhesion, improved chemical resistance, faster curing, increased crosslink density

3. Impact of BDMAEE on Coating Properties

The addition of BDMAEE to UV-curable coating formulations has a significant impact on the properties of the resulting coatings.

3.1. Crosslink Density:

The primary effect of BDMAEE is to increase the crosslink density of the coating network. This increase is a direct consequence of the mechanisms described in Section 1.2. Higher crosslink density translates to improved mechanical properties, chemical resistance, and, critically, UV stability.

3.2. Mechanical Properties:

Hardness: Increased crosslink density generally leads to higher hardness. This is because the denser network restricts the movement of polymer chains, making the coating more resistant to indentation.
Tensile Strength and Elongation: The effect on tensile strength and elongation is more complex and depends on the specific formulation. While higher crosslink density can increase tensile strength, it can also reduce elongation at break, making the coating more brittle. Careful optimization of the formulation is necessary to achieve the desired balance of these properties.
Abrasion Resistance: Higher crosslink density typically improves abrasion resistance. The denser network provides a stronger barrier against wear and tear.

Table 3: Effect of BDMAEE on Mechanical Properties (Typical Trends)

Property	Effect of Increasing BDMAEE Concentration	Explanation
Hardness	Increase	Denser network restricts chain movement, increasing resistance to indentation.
Tensile Strength	May Increase, then Plateau or Decrease	Initially increases due to stronger network, but excessive crosslinking can lead to brittleness.
Elongation at Break	Decrease	Increased crosslinking restricts chain movement, reducing the ability of the coating to stretch before breaking.
Abrasion Resistance	Increase	Denser network provides a stronger barrier against wear and tear.

3.3. Chemical Resistance:

Higher crosslink density enhances the chemical resistance of the coating. The denser network reduces the penetration of solvents, acids, and bases, protecting the underlying substrate from corrosion and degradation.

3.4. UV Stability:

The most significant benefit of using BDMAEE is the improvement in UV stability. Higher crosslink density reduces polymer chain mobility, minimizing the diffusion of degradation products formed during UV exposure. This reduces yellowing, cracking, and loss of gloss. Furthermore, a denser network can better withstand the stresses induced by UV radiation.

Table 4: Effect of BDMAEE on UV Stability (Typical Trends)

Property	Effect of Increasing BDMAEE Concentration	Explanation
Yellowing	Decrease	Reduced polymer chain mobility minimizes diffusion of yellowing degradation products.
Gloss Retention	Increase	Denser network resists surface degradation and maintains a smoother surface, preserving gloss.
Cracking	Decrease	Stronger network resists the stresses induced by UV radiation, reducing the formation of cracks.
Mechanical Strength after UV Exposure	Increase	Denser network slows down the degradation of mechanical properties upon UV exposure.

4. Factors Affecting the Performance of BDMAEE in UV-Curable Coatings

The effectiveness of BDMAEE in enhancing crosslink density and UV stability depends on several factors:

Resin System: The type of resin used (e.g., polyurethane, acrylate, epoxy) significantly affects the mechanism and extent of BDMAEE’s influence on crosslinking.
Photoinitiator: The choice of photoinitiator is crucial. Certain photoinitiators may be more compatible with BDMAEE than others, and some may even interact with BDMAEE in a detrimental way. Careful selection is essential.
BDMAEE Concentration: The optimal concentration of BDMAEE needs to be carefully determined. Too little BDMAEE may not provide sufficient crosslinking, while too much can lead to undesirable side effects, such as embrittlement or yellowing.
Curing Conditions: UV intensity, exposure time, and temperature all influence the curing process and the effectiveness of BDMAEE.
Additives: Other additives in the formulation, such as UV absorbers, hindered amine light stabilizers (HALS), and antioxidants, can interact with BDMAEE and affect its performance.

5. Formulation Considerations and Optimization

Formulating UV-curable coatings with BDMAEE requires careful consideration of the factors mentioned above. The following guidelines can help optimize the formulation:

Resin Selection: Choose a resin system that is compatible with BDMAEE and suitable for the desired application. Consider the functional groups present in the resin and their reactivity with BDMAEE.
Photoinitiator Selection: Select a photoinitiator that is compatible with both the resin system and BDMAEE. Avoid photoinitiators that generate acidic byproducts that can be neutralized by BDMAEE, as this can reduce its effectiveness as a crosslinking promoter.
BDMAEE Concentration Optimization: Perform a series of experiments to determine the optimal concentration of BDMAEE. Start with a low concentration and gradually increase it, monitoring the effect on crosslink density, mechanical properties, and UV stability. Techniques such as Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) can be used to assess crosslink density.
Additive Selection: Incorporate UV absorbers and HALS to further enhance UV stability. These additives work synergistically with BDMAEE to protect the coating from UV degradation. Antioxidants can also be added to prevent thermal oxidation during the curing process.
Curing Condition Optimization: Optimize the curing conditions to ensure complete curing and maximum crosslink density. Adjust the UV intensity, exposure time, and temperature as needed.
Testing and Evaluation: Thoroughly test and evaluate the performance of the coating, including mechanical properties, chemical resistance, and UV stability. Use standardized test methods to ensure accurate and reliable results.

6. Challenges and Future Trends

While BDMAEE offers significant benefits in enhancing crosslink density and UV stability, there are also some challenges associated with its use:

Yellowing: In some formulations, high concentrations of BDMAEE can contribute to yellowing of the coating, especially upon UV exposure. This can be mitigated by using lower concentrations of BDMAEE, incorporating UV absorbers and HALS, and selecting a photoinitiator that minimizes yellowing.
Odor: BDMAEE has a characteristic amine odor, which can be objectionable in some applications. Using encapsulated BDMAEE or incorporating odor masking agents can help reduce the odor.
Migration: BDMAEE can migrate out of the coating over time, especially in flexible coatings. This can lead to a reduction in performance and potential health and environmental concerns. Using higher molecular weight amine catalysts or chemically bonding the catalyst to the resin can help prevent migration.

Future trends in the use of BDMAEE in UV-curable coatings include:

Development of New BDMAEE Derivatives: Researchers are developing new derivatives of BDMAEE with improved properties, such as lower odor, reduced yellowing, and enhanced compatibility with various resin systems.
Combination with Nanomaterials: Combining BDMAEE with nanomaterials, such as silica nanoparticles or carbon nanotubes, can further enhance the mechanical properties, UV stability, and other performance characteristics of the coating.
Use in Waterborne UV-Curable Coatings: Waterborne UV-curable coatings are gaining popularity due to their low VOC emissions. BDMAEE can be used in these coatings to enhance crosslinking and improve performance.
Development of "Smart" UV-Curable Coatings: BDMAEE can be incorporated into "smart" UV-curable coatings that respond to external stimuli, such as temperature or pH. This can be used to create coatings with self-healing properties or other advanced functionalities.

7. Conclusion

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE) is a valuable additive for enhancing the crosslink density and UV stability of UV-curable coatings. Its ability to promote crosslinking reactions in various resin systems, particularly polyurethanes, acrylates, and epoxies, makes it a versatile tool for formulators. By carefully optimizing the formulation and curing conditions, BDMAEE can be used to create high-performance UV-curable coatings with excellent mechanical properties, chemical resistance, and UV stability. While challenges such as yellowing and odor need to be addressed, ongoing research and development are leading to new and improved BDMAEE derivatives and applications, paving the way for even more advanced UV-curable coating technologies. The continued exploration of BDMAEE’s potential will undoubtedly contribute to the development of more durable, sustainable, and high-performing coatings for a wide range of industries.

Literature Sources (Fictitious Examples – Replace with Actual Citations)

[1] Smith, A. B., & Jones, C. D. (2010). UV-Curable Coatings: Principles and Applications. Wiley-VCH.

[2] Brown, E. F., et al. (2015). The effect of tertiary amine catalysts on the UV stability of polyurethane coatings. Journal of Applied Polymer Science, 132(10), 41723.

[3] Garcia, L. M., & Rodriguez, P. R. (2018). Crosslinking mechanisms in acrylate-based UV-curable systems. Progress in Polymer Science, 80, 1-30.

[4] Lee, S. H., et al. (2020). Enhanced UV stability of epoxy coatings using bis[2-(N,N-Dimethylaminoethyl)] ether and hindered amine light stabilizers. Polymer Degradation and Stability, 175, 109113.

[5] Kim, J. Y., & Park, K. S. (2022). The role of BDMAEE in waterborne UV-curable polyurethane coatings. Journal of Coatings Technology and Research, 19(3), 657-667.

Main

Bis[2-(N,N-Dimethylaminoethyl)] Ether (BDMAEE) for Low-Migration Food Packaging Materials Compliance: A Comprehensive Overview

Introduction

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE), also known as DABCO® NE1060 (a registered trademark of Evonik Operations GmbH), is a tertiary amine catalyst widely employed in the production of polyurethane (PU) foams. Its primary role is to accelerate the reaction between isocyanates and polyols, leading to the formation of the urethane linkage. While BDMAEE offers significant benefits in PU foam manufacturing, its potential for migration from food packaging materials and subsequent consumer exposure raises concerns regarding food safety. This article provides a comprehensive overview of BDMAEE, focusing on its properties, applications in PU foam production, migration potential, regulatory compliance for food packaging materials, and strategies for minimizing its presence in food contact articles. We will explore various aspects, including product parameters, applications, safety considerations, and future trends, while adhering to rigorous and standardized language.

1. Product Overview

BDMAEE is a clear, colorless to slightly yellow liquid with a characteristic amine odor. It is soluble in water and most organic solvents. Its chemical structure features two dimethylaminoethyl groups linked by an ether linkage, providing two tertiary amine functionalities capable of catalyzing the urethane reaction.

1.1 Chemical Structure and Formula

Chemical Name: Bis[2-(N,N-Dimethylaminoethyl)] ether
Synonyms: 2,2′-Dimorpholinyldiethyl Ether; Dimethylaminoethyl Ether; DABCO® NE1060
CAS Registry Number: 3033-62-3
Molecular Formula: C₁₂H₂₆N₂O
Molecular Weight: 214.35 g/mol
Structural Formula: (CH₃)₂N-CH₂CH₂-O-CH₂CH₂-N(CH₃)₂

1.2 Physical and Chemical Properties

Property	Value	Unit
Appearance	Clear, colorless to slightly yellow liquid	–
Odor	Amine-like	–
Boiling Point	189-192	°C
Flash Point (Closed Cup)	68	°C
Density (20°C)	0.85-0.86	g/cm³
Refractive Index (20°C)	1.444-1.446	–
Viscosity (25°C)	2.5-3.5	mPa·s
Water Solubility	Soluble	–
Vapor Pressure (20°C)	<1	mmHg
Amine Value	515-535	mg KOH/g

1.3 Product Specifications

The following table presents typical product specifications for commercially available BDMAEE:

Parameter	Specification	Test Method
Assay (GC)	≥99.0%	Gas Chromatography
Water Content	≤0.2%	Karl Fischer Titration
Color (APHA)	≤20	ASTM D1209

2. Applications in Polyurethane Foam Production

BDMAEE is primarily used as a tertiary amine catalyst in the production of various types of PU foams, including flexible, rigid, and semi-rigid foams. Its efficacy in accelerating the urethane reaction makes it crucial for achieving desired foam properties and processing characteristics.

2.1 Catalytic Mechanism

BDMAEE acts as a nucleophilic catalyst, accelerating the reaction between isocyanates and polyols. The nitrogen atom in the tertiary amine group abstracts a proton from the hydroxyl group of the polyol, increasing its nucleophilicity and facilitating its attack on the electrophilic carbon atom of the isocyanate group. This process leads to the formation of the urethane linkage and the release of carbon dioxide, which acts as a blowing agent.

2.2 Types of PU Foams

Flexible Foams: Used in mattresses, upholstery, and automotive seating. BDMAEE helps control the cell structure and density of flexible foams, contributing to their comfort and resilience.
Rigid Foams: Used in insulation panels, refrigerators, and structural components. BDMAEE is crucial for achieving the desired closed-cell structure and thermal insulation properties of rigid foams.
Semi-Rigid Foams: Used in automotive parts and packaging applications. BDMAEE provides a balance between flexibility and rigidity, making these foams suitable for impact absorption and cushioning.

2.3 Advantages of Using BDMAEE

High Catalytic Activity: BDMAEE is a highly efficient catalyst, requiring relatively low concentrations to achieve desired reaction rates.
Good Solubility: Its solubility in polyols and isocyanates ensures uniform distribution within the reaction mixture, leading to consistent foam properties.
Controlled Reaction Rate: BDMAEE allows for precise control over the urethane reaction rate, enabling optimization of foam processing parameters.
Improved Foam Properties: BDMAEE can contribute to improved foam properties, such as cell structure, density, and mechanical strength.

3. Migration Potential and Food Safety Concerns

While BDMAEE is essential for PU foam production, its potential to migrate from food packaging materials into food poses a risk to consumer health. The migration process is influenced by several factors, including the concentration of BDMAEE in the foam, the type of food being packaged, the temperature and duration of storage, and the barrier properties of the packaging material.

3.1 Factors Influencing Migration

Concentration in the Foam: Higher concentrations of BDMAEE in the PU foam increase the driving force for migration.
Type of Food: Fatty foods tend to absorb more BDMAEE than aqueous foods due to the lipophilic nature of the amine.
Temperature and Duration: Elevated temperatures and prolonged storage periods accelerate the migration process.
Packaging Material: The barrier properties of the packaging material play a crucial role in preventing or minimizing migration. Materials with low permeability to BDMAEE, such as aluminum foil or certain polymers with high density, can effectively reduce migration.
Foam Structure: Open-cell foams generally exhibit higher migration rates compared to closed-cell foams due to the larger surface area exposed to the food.

3.2 Health Risks Associated with Exposure

Exposure to BDMAEE through food consumption can potentially lead to various health effects, including:

Irritation: BDMAEE can cause irritation of the skin, eyes, and respiratory tract upon direct contact.
Allergic Reactions: Some individuals may experience allergic reactions upon exposure to BDMAEE.
Toxicological Concerns: Studies have raised concerns about the potential for BDMAEE to cause developmental or reproductive toxicity at high doses. Further research is needed to fully assess the long-term health effects of low-level exposure through food consumption.

3.3 Methods for Detecting Migration

Several analytical techniques are employed to detect and quantify the migration of BDMAEE from food packaging materials into food simulants. These methods typically involve extraction, separation, and detection steps.

Gas Chromatography-Mass Spectrometry (GC-MS): This technique is widely used for identifying and quantifying volatile organic compounds, including BDMAEE, in food simulants.
Liquid Chromatography-Mass Spectrometry (LC-MS): This technique is suitable for analyzing non-volatile or thermally labile compounds, and can be used to detect BDMAEE after derivatization.
Headspace Gas Chromatography (HS-GC): This technique involves analyzing the volatile compounds present in the headspace above a sample, providing a sensitive method for detecting BDMAEE migration.

4. Regulatory Compliance for Food Packaging Materials

Due to the potential health risks associated with BDMAEE migration, regulatory bodies worldwide have established guidelines and regulations governing its use in food packaging materials. These regulations aim to minimize consumer exposure to BDMAEE and ensure food safety.

4.1 European Union (EU)

Regulation (EC) No 1935/2004: This framework regulation establishes the general principles for all food contact materials, requiring them to be safe, inert, and not to transfer their constituents to food in quantities that could endanger human health or bring about an unacceptable change in the composition of the food.
Regulation (EU) No 10/2011: This regulation specifically addresses plastic materials and articles intended to come into contact with food. It establishes specific migration limits (SMLs) for certain substances, including amines, but does not have a specific SML for BDMAEE. However, it does include an overall migration limit (OML) of 10 mg/dm² for plastic materials. Manufacturers must ensure that the total migration of all substances from the plastic material does not exceed this limit.
EFSA Opinions: The European Food Safety Authority (EFSA) provides scientific opinions on the safety of substances used in food contact materials. EFSA has evaluated the safety of BDMAEE and may provide guidance on acceptable exposure levels.

4.2 United States (US)

Food and Drug Administration (FDA): The FDA regulates food contact substances in the US. Substances used in food packaging must be either generally recognized as safe (GRAS) or approved through a food contact notification (FCN) process. While BDMAEE is not specifically listed in FDA regulations for direct food contact, it may be used in indirect food contact applications if it meets certain criteria and does not result in significant migration into food.
21 CFR Part 175: This section of the Code of Federal Regulations addresses indirect food additives, including components of paper and paperboard in contact with food.
21 CFR Part 177: This section addresses indirect food additives, including polymers.

4.3 China

GB Standards: China has a series of national standards (GB standards) that regulate food contact materials and articles. These standards specify requirements for materials, testing methods, and migration limits. Relevant GB standards include:
- GB 4806.1-2016: General safety requirements for food contact materials and articles.
- GB 9685-2016: Hygienic standards for uses of additives in food containers and packaging materials.
- GB 31604.1-2015: General principles for the migration test of food contact materials and articles.

4.4 Other Regions

Many other countries and regions have their own regulations and guidelines for food contact materials, often based on the principles established by the EU and the US. Manufacturers must comply with the specific regulations of the countries where their products are sold.

5. Strategies for Minimizing BDMAEE Migration

Several strategies can be implemented to minimize the migration of BDMAEE from PU foams used in food packaging applications. These strategies focus on reducing the concentration of BDMAEE in the foam, improving the foam’s structure, and enhancing the barrier properties of the packaging material.

5.1 Reducing BDMAEE Concentration

Optimize Catalyst Dosage: Carefully optimize the dosage of BDMAEE to ensure that only the minimum amount required for achieving desired foam properties is used.
Use Alternative Catalysts: Explore the use of alternative catalysts that are less prone to migration or have lower toxicity profiles. Examples include reactive amine catalysts that become chemically bound to the polymer matrix during the foaming process, or metal catalysts.
Post-Curing: Implement a post-curing process to further react any residual isocyanates and polyols, reducing the potential for BDMAEE release. Post-curing involves exposing the foam to elevated temperatures for a specified period, promoting further crosslinking and reducing the concentration of unreacted components.

5.2 Improving Foam Structure

Closed-Cell Foam: Utilize closed-cell foam structures whenever possible, as they offer a lower surface area for migration compared to open-cell foams.
Optimize Cell Size: Optimize the cell size and uniformity of the foam to minimize the surface area exposed to the food.
Surface Treatment: Apply surface treatments to the foam to seal the surface and reduce migration.

5.3 Enhancing Barrier Properties

Lamination: Laminate the PU foam with a barrier layer, such as aluminum foil, polyethylene (PE), or polypropylene (PP), to prevent migration.
Coatings: Apply barrier coatings to the surface of the foam to reduce its permeability to BDMAEE.
Modified Atmosphere Packaging (MAP): Employ modified atmosphere packaging techniques to reduce the rate of degradation and migration.

5.4 Selection of Raw Materials

High-Purity Raw Materials: Use high-purity polyols and isocyanates to minimize the presence of impurities that could contribute to migration.
Low-Migration Additives: Select additives, such as surfactants and stabilizers, that have low migration potential.

6. Future Trends and Research Directions

The field of food packaging materials is constantly evolving, with a focus on developing safer and more sustainable solutions. Future trends and research directions related to BDMAEE and other amine catalysts include:

Development of Reactive Amine Catalysts: Research is ongoing to develop reactive amine catalysts that become chemically bound to the polymer matrix during the foaming process, eliminating the potential for migration.
Bio-Based Catalysts: Exploration of bio-based catalysts derived from renewable resources as alternatives to traditional amine catalysts.
Advanced Analytical Techniques: Development of more sensitive and accurate analytical techniques for detecting and quantifying trace levels of amine migration in food simulants.
Risk Assessment and Modeling: Refinement of risk assessment models to better predict the migration behavior of amine catalysts and assess the potential health risks associated with exposure.
Sustainable Packaging Materials: Development of sustainable packaging materials that are biodegradable or compostable, reducing the environmental impact of food packaging waste.

7. Conclusion

BDMAEE is a valuable catalyst in the production of PU foams used in various applications, including food packaging. However, its potential for migration and associated health risks necessitate careful consideration and implementation of strategies to minimize exposure. Regulatory compliance is paramount, and manufacturers must adhere to the specific regulations of the countries where their products are sold. By optimizing catalyst dosage, improving foam structure, enhancing barrier properties, and exploring alternative catalysts, it is possible to significantly reduce the migration of BDMAEE and ensure the safety of food packaging materials. Continued research and development efforts are crucial for advancing the field of food packaging materials and creating safer and more sustainable solutions for the future. The ongoing development of reactive and bio-based catalysts, along with advanced analytical techniques and refined risk assessment models, will contribute to minimizing the risks associated with amine migration and ensuring the safety of food products for consumers.

Literature Sources

EFSA (European Food Safety Authority). Scientific Opinion on the safety assessment of substances used in plastic food contact materials. EFSA Journal, various years. (Note: Specify the relevant EFSA opinions based on specific substances and years)
FDA (U.S. Food and Drug Administration). Code of Federal Regulations, Title 21, Parts 175 and 177.
GB Standards. National Standards of the People’s Republic of China for Food Contact Materials and Articles. (Note: Specify the relevant GB standards based on material type and application)
Kirwan, M. J., & Strawbridge, J. W. (2003). Plastics packaging and food safety. Pira International.
Robertson, G. L. (2016). Food Packaging: Principles and Practice. CRC press.
Wypych, G. (2017). Handbook of Polymers. ChemTec Publishing.
Dominguez, A. R., et al. (2019). Migration of amine catalysts from polyurethane foams into food simulants. Food Chemistry, 283, 450-457. (Note: This is a placeholder, replace with actual relevant research papers).
Smith, J. P., et al. (2020). Evaluation of alternative catalysts for polyurethane foam production with reduced migration potential. Journal of Applied Polymer Science, 137(10), 48501. (Note: This is a placeholder, replace with actual relevant research papers).

This article provides a detailed overview of BDMAEE, its applications, safety concerns, and strategies for minimizing migration. Remember to replace the placeholder literature sources with actual relevant research papers.

Main

Optimizing Cure Profiles Using Bis[2-(N,N-Dimethylaminoethyl)] Ether in Flexible Polyurethane Foams

Introduction

Flexible polyurethane (PU) foams are widely used in various applications, including furniture, bedding, automotive interiors, and packaging, due to their excellent cushioning properties, high resilience, and cost-effectiveness. The formation of flexible PU foam involves a complex interplay of chemical reactions, primarily the reaction between polyols and isocyanates, leading to chain extension and crosslinking, coupled with blowing reactions generating carbon dioxide gas that expands the polymer matrix. The balance between these reactions is crucial for achieving the desired foam properties, such as density, cell size, and mechanical strength. Catalysts play a vital role in controlling the kinetics and selectivity of these reactions.

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE), often referred to as a blowing catalyst, is a tertiary amine catalyst extensively used in flexible PU foam production. It is known for its selective promotion of the water-isocyanate reaction, generating carbon dioxide, which acts as the blowing agent. The efficacy of BDMAEE in achieving optimal foam properties is highly dependent on its concentration, the type of polyol and isocyanate used, and the presence of other additives. This article will delve into the role of BDMAEE in flexible PU foam cure profiles, focusing on its reaction mechanism, effects on foam properties, optimization strategies, and a comparison with other commonly used amine catalysts.

1. Flexible Polyurethane Foam Formation: A Chemical Overview

The production of flexible PU foam primarily involves two key reactions:

Polyol-Isocyanate Reaction (Gelation): This reaction involves the nucleophilic attack of a hydroxyl group (-OH) from the polyol on the isocyanate group (-NCO), forming a urethane linkage (-NHCOO-). This reaction leads to chain extension and crosslinking, increasing the viscosity of the reaction mixture and providing structural integrity to the foam.
```
R-OH + R'-NCO  →  R-NHCOO-R'
```
Water-Isocyanate Reaction (Blowing): Water reacts with the isocyanate group to form an unstable carbamic acid, which then decomposes into an amine and carbon dioxide. The carbon dioxide gas expands the polymer matrix, creating the cellular structure of the foam.
```
R-NCO + H2O  →  R-NHCOOH  →  R-NH2 + CO2
```
```
R-NH2 + R'-NCO  →  R-NHCONH-R' (Urea)
```

The urea formed in the second step further reacts with isocyanate, contributing to chain extension and crosslinking. The relative rates of these two reactions significantly influence the final foam structure and properties.

1.1 Raw Materials

Several raw materials are essential for the production of flexible polyurethane foam:

Polyols: These are the primary reactants, contributing to the polymer backbone. Common polyols used in flexible PU foam include polyether polyols and polyester polyols. Their molecular weight, functionality (number of hydroxyl groups per molecule), and type determine the foam’s flexibility, resilience, and other properties.
Isocyanates: These react with polyols and water to form the polymer network and generate CO2. Toluene diisocyanate (TDI) and methylene diphenyl diisocyanate (MDI) are the most common isocyanates used. The choice between TDI and MDI significantly affects the foam’s processing characteristics and final properties.
Water: Water acts as the primary blowing agent, reacting with isocyanate to generate carbon dioxide. The amount of water used directly controls the foam’s density.
Catalysts: Catalysts accelerate the polyol-isocyanate and water-isocyanate reactions. Amine catalysts and organometallic catalysts are typically used in combination to achieve the desired reaction balance.
Surfactants: Surfactants stabilize the foam bubbles during expansion, preventing collapse and ensuring a uniform cell structure. Silicone surfactants are commonly used.
Other Additives: Flame retardants, colorants, fillers, and stabilizers may be added to modify the foam’s properties and processing characteristics.

2. Bis[2-(N,N-Dimethylaminoethyl)] Ether (BDMAEE): Properties and Mechanism

BDMAEE is a tertiary amine catalyst with the chemical formula (CH3)2NCH2CH2OCH2CH2N(CH3)2. It is a colorless to slightly yellow liquid with a characteristic amine odor.

Table 1: Physical and Chemical Properties of BDMAEE

Property	Value
Molecular Weight	160.26 g/mol
Boiling Point	160-163 °C
Density	0.85 g/cm³ at 20 °C
Flash Point	51 °C
Vapor Pressure	0.4 kPa at 20 °C
Solubility	Soluble in water, alcohols, and many organic solvents

2.1 Catalytic Mechanism

BDMAEE acts as a nucleophilic catalyst, accelerating the reaction between water and isocyanate. The mechanism involves the following steps:

Proton Abstraction: The lone pair of electrons on the nitrogen atom of BDMAEE abstracts a proton from a water molecule, generating a hydroxyl ion (OH⁻) and a protonated amine catalyst.
Nucleophilic Attack: The hydroxyl ion then attacks the electrophilic carbon atom of the isocyanate group, forming a carbamate intermediate.
Proton Transfer: A proton is transferred from the protonated amine catalyst to the carbamate intermediate, leading to the formation of carbamic acid.
Decomposition: The carbamic acid decomposes into an amine and carbon dioxide. The amine can then react with another isocyanate molecule to form urea.

The catalyst is regenerated in the process, allowing it to participate in subsequent reactions. The selectivity of BDMAEE towards the water-isocyanate reaction is attributed to its steric hindrance and electronic effects, which favor the activation of water over polyols.

3. Influence of BDMAEE on Foam Properties

The concentration of BDMAEE significantly influences the cure profile and final properties of flexible PU foam.

3.1 Impact on Reaction Kinetics

Cream Time: Cream time is the time elapsed from the mixing of all ingredients until the mixture starts to rise. BDMAEE accelerates the initial stages of the reaction, leading to a shorter cream time. Higher concentrations of BDMAEE result in even faster cream times.
Rise Time: Rise time is the time elapsed from the mixing of all ingredients until the foam reaches its maximum height. BDMAEE promotes the generation of carbon dioxide, accelerating the blowing process and shortening the rise time.
Gel Time: Gel time is the time elapsed until the foam loses its fluidity and becomes a gel. BDMAEE indirectly affects gel time by influencing the consumption of isocyanate. However, the primary driver of gel time is the polyol-isocyanate reaction, which is typically catalyzed by a separate gelation catalyst.

3.2 Impact on Foam Structure

Cell Size: The concentration of BDMAEE affects the cell size of the foam. Higher concentrations of BDMAEE can lead to smaller cell sizes due to the faster generation of carbon dioxide, which creates more nucleation sites for bubble formation. However, excessive amounts of BDMAEE can lead to very small and closed cells, which can negatively impact the foam’s breathability and compression set.
Cell Opening: BDMAEE promotes the opening of cells during the foam expansion process. This is crucial for achieving good airflow and breathability in flexible PU foam. The proper balance of blowing and gelation reactions, facilitated by BDMAEE, ensures that the cell walls rupture before the foam solidifies, creating an open-cell structure.
Foam Density: The amount of water and BDMAEE used directly affects the foam’s density. Increasing the concentration of BDMAEE, while keeping the water content constant, generally leads to a lower density foam due to the increased efficiency of carbon dioxide generation.

3.3 Impact on Mechanical Properties

Tensile Strength: Tensile strength is the maximum stress a material can withstand before breaking under tension. The concentration of BDMAEE can indirectly affect tensile strength by influencing the foam’s cell structure and density. A more uniform and open-cell structure, achieved with optimized BDMAEE levels, can contribute to higher tensile strength.
Tear Strength: Tear strength is the resistance of a material to tearing. Similar to tensile strength, tear strength is influenced by the foam’s cell structure and density.
Compression Set: Compression set is a measure of the permanent deformation of a material after being subjected to a compressive load for a specific period. Optimized BDMAEE concentrations can contribute to lower compression set values, indicating better long-term performance of the foam.
Resilience: Resilience is the ability of a material to recover its original shape after being deformed. The appropriate level of BDMAEE helps achieve the optimal balance between blowing and gelation reactions, resulting in a foam with good resilience.

Table 2: Influence of BDMAEE Concentration on Foam Properties

BDMAEE Concentration	Cream Time	Rise Time	Cell Size	Cell Opening	Density	Tensile Strength	Compression Set	Resilience
Low	Longer	Longer	Larger	Less	Higher	Lower	Higher	Lower
Optimal	Moderate	Moderate	Moderate	Good	Optimal	Optimal	Optimal	Optimal
High	Shorter	Shorter	Smaller	More (but can lead to closed cells)	Lower	Lower	Higher	Lower

4. Optimization Strategies for BDMAEE Usage

Optimizing the use of BDMAEE in flexible PU foam formulations requires careful consideration of various factors, including the type of polyol and isocyanate, the desired foam properties, and the presence of other additives.

4.1 Formulation Adjustments

Polyol Selection: The type of polyol used (e.g., polyether polyol, polyester polyol) significantly impacts the reaction kinetics and foam properties. Adjusting the BDMAEE concentration based on the polyol’s reactivity is crucial. For example, more reactive polyols may require lower BDMAEE concentrations to avoid excessively fast reactions.
Isocyanate Index: The isocyanate index, defined as the ratio of isocyanate groups to hydroxyl groups (NCO/OH), affects the crosslinking density and foam hardness. Adjusting the isocyanate index in conjunction with BDMAEE optimization can fine-tune the foam’s mechanical properties.
Water Content: The amount of water used as a blowing agent directly influences the foam’s density. Optimizing the water content in conjunction with BDMAEE concentration is essential to achieve the desired density and cell structure.
Surfactant Selection: Surfactants play a crucial role in stabilizing the foam bubbles and ensuring a uniform cell structure. The choice of surfactant should be compatible with the BDMAEE catalyst and other formulation components.
Co-Catalysts: BDMAEE is often used in combination with a gelation catalyst, typically an organometallic catalyst such as stannous octoate. Optimizing the ratio of BDMAEE to the gelation catalyst is crucial for achieving the desired balance between blowing and gelation reactions. Delayed-action catalysts can also be considered to provide better control over the reaction profile.

4.2 Processing Parameters

Mixing Speed: The mixing speed during foam production affects the homogeneity of the reaction mixture and the dispersion of the catalyst. Optimizing the mixing speed ensures that the BDMAEE catalyst is uniformly distributed throughout the formulation.
Temperature: The temperature of the raw materials and the reaction mixture influences the reaction kinetics. Maintaining a consistent temperature is important for reproducible foam properties.
Machine Settings: For automated foam production, optimizing machine settings such as pump rates and mixing head pressure is crucial for consistent and efficient processing.

4.3 Experimental Design and Statistical Analysis

Design of Experiments (DOE): DOE techniques, such as factorial designs and response surface methodology (RSM), can be used to systematically investigate the effects of BDMAEE concentration, water content, isocyanate index, and other formulation variables on foam properties.
Statistical Analysis: Statistical software can be used to analyze the experimental data and identify the optimal combination of variables that yields the desired foam properties.

Table 3: Optimization Strategies for BDMAEE Usage

Parameter	Optimization Strategy
Polyol Type	Adjust BDMAEE concentration based on polyol reactivity; more reactive polyols may require lower BDMAEE levels.
Isocyanate Index	Optimize isocyanate index in conjunction with BDMAEE to fine-tune crosslinking density and foam hardness.
Water Content	Optimize water content alongside BDMAEE to achieve the desired density and cell structure.
Surfactant	Select a surfactant compatible with BDMAEE and other formulation components to ensure foam stability.
Co-Catalysts	Optimize the ratio of BDMAEE to gelation catalyst to balance blowing and gelation reactions. Consider delayed-action catalysts for better control.
Mixing Speed	Optimize mixing speed to ensure uniform catalyst distribution.
Temperature	Maintain consistent temperature of raw materials and reaction mixture for reproducible results.
DOE & Statistical Analysis	Use DOE techniques and statistical software to systematically investigate variable effects and identify optimal combinations.

5. Comparison with Other Amine Catalysts

While BDMAEE is a widely used blowing catalyst, other amine catalysts are also employed in flexible PU foam production, each with its own advantages and disadvantages.

Triethylenediamine (TEDA): TEDA is a strong gelation catalyst that primarily promotes the polyol-isocyanate reaction. It is often used in combination with BDMAEE to achieve a balance between blowing and gelation.
N,N-Dimethylcyclohexylamine (DMCHA): DMCHA is a versatile catalyst that exhibits both blowing and gelation activity. Its selectivity can be adjusted by varying its concentration and the presence of other additives.
Pentamethyldiethylenetriamine (PMDETA): PMDETA is a highly active catalyst that promotes both blowing and gelation reactions. It is often used in low concentrations to achieve fast cure rates.

Table 4: Comparison of Amine Catalysts

Catalyst	Primary Activity	Advantages	Disadvantages
BDMAEE	Blowing	Selective promotion of water-isocyanate reaction, good cell opening, contributes to lower density.	Can lead to excessive blowing if not properly controlled, potential odor issues.
TEDA	Gelation	Strong promotion of polyol-isocyanate reaction, enhances crosslinking and mechanical strength.	Can lead to closed cells if used in excess, may result in slower rise times.
DMCHA	Blowing/Gelation	Versatile catalyst with adjustable selectivity, can be used to achieve a balance between blowing and gelation.	Requires careful optimization to avoid imbalances, can be less effective than specialized catalysts.
PMDETA	Blowing/Gelation	Highly active, promotes fast cure rates, can be used in low concentrations.	Can be difficult to control, may lead to uneven cell structure or premature gelling.

The choice of catalyst or catalyst blend depends on the specific formulation and desired foam properties. BDMAEE is often preferred when a strong blowing effect is required to achieve low density and good cell opening, while TEDA is used to enhance gelation and improve mechanical strength. DMCHA and PMDETA offer more versatility but require careful optimization to achieve the desired balance.

6. Safety and Handling Considerations

BDMAEE, like other amine catalysts, should be handled with care. It is a corrosive and potentially irritating substance. Proper safety precautions should be taken to avoid skin and eye contact, inhalation, and ingestion.

Personal Protective Equipment (PPE): Wear appropriate PPE, including gloves, safety glasses, and a respirator, when handling BDMAEE.
Ventilation: Work in a well-ventilated area to minimize inhalation of vapors.
Storage: Store BDMAEE in a cool, dry place away from incompatible materials such as strong acids and oxidizers.
Disposal: Dispose of BDMAEE waste according to local regulations.

7. Future Trends and Developments

Research and development efforts are focused on developing new and improved amine catalysts with enhanced selectivity, lower odor, and reduced volatile organic compound (VOC) emissions. These new catalysts aim to provide better control over the foam formation process, improve foam properties, and address environmental concerns. Examples include:

Reactive Amine Catalysts: These catalysts are chemically incorporated into the polymer matrix during the reaction, reducing VOC emissions and improving foam durability.
Blocked Amine Catalysts: These catalysts are temporarily deactivated and released gradually during the reaction, providing better control over the cure profile.
Bio-Based Amine Catalysts: These catalysts are derived from renewable resources, offering a more sustainable alternative to traditional petroleum-based catalysts.

Conclusion

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE) is a valuable blowing catalyst in the production of flexible polyurethane foams. Its selective promotion of the water-isocyanate reaction allows for precise control over the blowing process, leading to foams with desirable properties such as low density, good cell opening, and optimal mechanical performance. However, achieving optimal results requires careful optimization of BDMAEE concentration, formulation adjustments, and consideration of processing parameters. Understanding the catalytic mechanism, influence on foam properties, and comparison with other amine catalysts is essential for effectively utilizing BDMAEE in flexible PU foam production. Continued research and development efforts are focused on developing new and improved amine catalysts with enhanced performance and reduced environmental impact, paving the way for more sustainable and high-performance flexible PU foams.

Literature Sources:

Szycher, M. (1999). Szycher’s Handbook of Polyurethanes. CRC Press.
Oertel, G. (1993). Polyurethane Handbook. Hanser Gardner Publications.
Rand, L., & Frisch, K. C. (1962). Polyurethanes. Progress in Polymer Science, 2, 2-70.
Woods, G. (1990). The ICI Polyurethanes Book. John Wiley & Sons.
Ashida, K. (2006). Polyurethane and Related Foams: Chemistry and Technology. CRC Press.
Saunders, J. H., & Frisch, K. C. (1962). Polyurethanes: Chemistry and Technology. Interscience Publishers.
Proskurina, V. E., et al. "Kinetics of the reaction of isocyanates with water in the presence of tertiary amine catalysts." Russian Journal of Applied Chemistry 76.12 (2003): 1931-1935.
Ferrigno, T. H. (2012). Rigid Polyurethane Foams: Technology and Applications. CRC Press.
Hepburn, C. (1991). Polyurethane Elastomers. Elsevier Science Publishers.
Klempner, D., & Frisch, K. C. (Eds.). (1991). Handbook of Polymeric Foams and Foam Technology. Hanser Gardner Publications.

Main

CAS 68928-76-7/Dimethylbis[(1-oxoneodecyl)oxy]stannane

Overview:

Name: dimethyltin dixynodecanoate, CAS 68928-76-7, Dimethyldineodecanoatetin, Fomrez UL-28

Dimethyldecanoatetin is an organic compound with the chemical formula C12H44O4Sn.

Product Name: Dimethyldimethyltin dixynodecanoate 68928-76-7

Product code: DDDO

Chinese name: Dimethyltin dixynodecanoate

Foreign name Dimethylbis[(1-oxoneodecyl)oxy]stannane

Molecular Formula: C12H44O4Sn

CAS No.: 68928-76-7

Item Indicator

Appearance Clarified viscous liquid

Color (Pt-Co No.) ≤50

Refractive index (25℃) 1,4630 – 1,4730

Density (25℃) 1,1230 – 1,1630

Tin content 22,50% – 24,50%

Moisture < 0,40%

Chlorine content < 0,20

English name: Dimethyldineodecanoatetin

CAS No.: 68928-76-7

Molecular Formula: C22H44O4SN

Production method:

Made from dichlorodimethyltin and neodecanoic acid by dehydrochlorination reaction.

Environmental Impact:

OSHA Environmental Safety Standard for the use of organotins in all industries [ 8H TWA (8-hour average) is 0.1 mg/m (in tin); short-term exposure value is 0.2 mg/m];

Uses:

Clarifying viscous liquid

Used as an efficient catalyst in the manufacture of polyurethane foams, coatings, adhesives and sealants. Used as hardening catalyst for two-component polyurethane, polyester, nitrocellulose lacquer, ink and other coatings and warm-air hardening coatings with good oxidation resistance; used as a catalyst for the production of urethane plastics, urethane coatings, silicone rubber, catalysts, and other uses.

Storage method:

Room temperature, avoid light, ventilated dry place, sealed storage

Storage and transportation:

Store in sealed containers and in a cool, dry place. The place of storage must be locked and the key must be given to the technical experts and their assistants for safekeeping. The storage place must be kept away from oxidizing agents and away from water sources.

Packed in general-purpose plastic and plastic-sprayed iron drums or glass containers and transported according to general chemical management regulations.

Packaging:

Packing: it is preferable to use glass containers, plastic containers, chlorine corrosion-resistant metal utensils to contain, sealed and stored. Store in a cool and dry place, keep the container sealed and avoid contact with oxides. Do not inhale dust, avoid contact with skin and mucous membranes. Smoking, eating and drinking are prohibited in the workplace. After work, shower and change clothes. Store contaminated clothing separately and wash before use. Maintain good hygiene practices.

Company Name:	Newtop Chemical Materials (Shanghai) Co., Ltd.
Sales Manager:	Hunter
E_Mail:	[email protected]
Telephone:	86-021-5657 7831
Fax:	86-021-5657 7830
Address:	Rm. 1104, No. 258, Songxing West Road, Baoshan District, Shanghai, China (Mainland)
Website:	www.newtopchem.com

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CAS 68928-76-7/Dimethylbis[(1-oxoneodecyl)oxy]stannane

Overview:

Name: dimethyltin dixynodecanoate, CAS 68928-76-7, Dimethyldineodecanoatetin, Fomrez UL-28

Dimethyldecanoatetin is an organic compound with the chemical formula C12H44O4Sn.

Product Name: Dimethyldimethyltin dixynodecanoate 68928-76-7

Product code: DDDO

Chinese name: Dimethyltin dixynodecanoate

Foreign name Dimethylbis[(1-oxoneodecyl)oxy]stannane

Molecular Formula: C12H44O4Sn

CAS No.: 68928-76-7

Item Indicator

Appearance Clarified viscous liquid

Color (Pt-Co No.) ≤50

Refractive index (25℃) 1,4630 – 1,4730

Density (25℃) 1,1230 – 1,1630

Tin content 22,50% – 24,50%

Moisture < 0,40%

Chlorine content < 0,20

English name: Dimethyldineodecanoatetin

CAS No.: 68928-76-7

Molecular Formula: C22H44O4SN

Production method:

Made from dichlorodimethyltin and neodecanoic acid by dehydrochlorination reaction.

Environmental Impact:

OSHA Environmental Safety Standard for the use of organotins in all industries [ 8H TWA (8-hour average) is 0.1 mg/m (in tin); short-term exposure value is 0.2 mg/m];

Uses:

Clarifying viscous liquid

Storage method:

Room temperature, avoid light, ventilated dry place, sealed storage

Storage and transportation:

Store in sealed containers and in a cool, dry place. The place of storage must be locked and the key must be given to the technical experts and their assistants for safekeeping. The storage place must be kept away from oxidizing agents and away from water sources.

Packed in general-purpose plastic and plastic-sprayed iron drums or glass containers and transported according to general chemical management regulations.

Packaging:

Company Name:

Newtop Chemical Materials (Shanghai) Co., Ltd.

Sales Manager:

Hunter

E_Mail:

Telephone:

86-021-5657 7831

Fax:

86-021-5657 7830

Address:

Rm. 1104, No. 258, Songxing West Road, Baoshan District, Shanghai, China (Mainland)

Website:

Rm. 1104, No. 258, Songxing West Road,
Baoshan District, Shanghai, China (Mainland)