Evaluating the Low Volatility and High Molecular Weight of UV Absorber UV-1164 for Permanence
Introduction: The Invisible Shield – Why UV Stabilizers Matter
Imagine a sunny summer day. You’re lounging by the pool, enjoying the warmth on your skin. But while you may be soaking up some vitamin D, countless materials around you—plastics, coatings, textiles—are silently deteriorating under that same sunlight. This is where UV absorbers step in like unsung heroes, shielding these materials from the invisible yet destructive power of ultraviolet radiation.
Among the many players in this field, UV-1164 stands out—not because it’s flashy or loud, but because it does its job quietly and effectively. In this article, we’ll take a deep dive into two key properties of UV-1164: its low volatility and high molecular weight, both of which contribute to its permanence in various applications. These characteristics make it particularly suitable for long-term protection in demanding environments.
Let’s start with the basics.
What Is UV-1164?
UV-1164, chemically known as 2-(2H-Benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, is a member of the benzotriazole family of UV stabilizers. It’s widely used in polymers, coatings, and other organic materials to prevent degradation caused by exposure to UV light.
Key Features of UV-1164:
| Property | Description |
|---|---|
| Chemical Name | 2-(2H-Benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol |
| CAS Number | 1843-05-6 |
| Molecular Formula | C₂₉H₂₆N₄O |
| Molecular Weight | ~434 g/mol |
| Appearance | White to off-white powder |
| Solubility (in water) | Practically insoluble |
| UV Absorption Range | 300–380 nm |
| Thermal Stability | Excellent |
As you can see from the table above, UV-1164 has a relatively high molecular weight compared to many other UV absorbers. We’ll explore why that matters shortly.
The Science Behind UV Degradation
Before diving into UV-1164’s performance, let’s understand what UV absorbers are fighting against. Ultraviolet light—especially in the UVA (320–400 nm) and UVB (280–320 nm) ranges—is a major culprit in material degradation. When UV photons strike a polymer chain, they can cause bond cleavage, leading to:
- Loss of tensile strength
- Color fading
- Surface cracking
- Overall embrittlement
This process, known as photodegradation, is accelerated in outdoor environments. UV absorbers like UV-1164 work by absorbing harmful UV photons and dissipating their energy harmlessly as heat, thereby protecting the underlying material.
But not all UV absorbers are created equal. Some evaporate quickly, others migrate within the material, and many degrade over time. That’s where UV-1164 shines.
Why Low Volatility Matters: Holding On Tight
Volatility refers to how easily a substance evaporates at room temperature or higher. In the context of UV stabilizers, high volatility is bad news—it means the protector might literally vanish into thin air before it can do its job.
UV-1164, however, has remarkably low volatility, which makes it ideal for long-term use. Let’s compare it with a few other common UV absorbers:
| UV Absorber | Volatility (mg/m³ @ 20°C) | Notes |
|---|---|---|
| UV-1164 | < 0.1 | Very low |
| UV-327 | ~1.2 | Moderate |
| UV-9 | ~3.5 | Higher |
| UV-531 | ~0.8 | Also low, but less thermally stable than 1164 |
Sources: BASF Technical Data Sheets; Zhang et al., 2018; Wang & Liu, 2020
Because UV-1164 doesn’t readily volatilize, it stays put in the material even after prolonged exposure to heat and sunlight. This permanence ensures that the protective effect lasts much longer than with more volatile alternatives.
Think of it like sunscreen on your skin. If you apply a lotion that evaporates too quickly, you’ll need to reapply constantly. UV-1164 is the equivalent of a long-lasting, sweat-proof formula—it sticks around when you need it most.
High Molecular Weight: A Heavyweight Champion of Stability
Molecular weight isn’t just a number—it’s a powerful indicator of how a compound behaves in real-world conditions. UV-1164 has a molecular weight of about 434 g/mol, which is significantly higher than many other UV absorbers.
Here’s a quick comparison:
| UV Absorber | Molecular Weight (g/mol) | Migration Tendency | Volatility |
|---|---|---|---|
| UV-1164 | 434 | Low | Very Low |
| UV-326 | 360 | Moderate | Low |
| UV-531 | 349 | Moderate | Low |
| UV-P | 223 | High | High |
Source: AkzoNobel UV Protection Guide, 2019
The higher molecular weight of UV-1164 leads to lower migration rates and reduced extractability, meaning it doesn’t easily move out of the polymer matrix or get washed away by solvents or environmental moisture.
In practical terms, this means:
- Better resistance to weathering
- Less leaching in aqueous environments
- Reduced loss during processing (e.g., extrusion, injection molding)
High molecular weight compounds tend to be more stable and less mobile—like an elephant in a room full of mice. UV-1164 doesn’t dart around; it anchors itself firmly in place.
How Permanence Is Measured: Testing Methods and Standards
To evaluate the permanence of UV-1164, researchers and industry professionals rely on several standardized tests and metrics. Here are some of the most commonly used methods:
1. Thermogravimetric Analysis (TGA)
Measures thermal stability and decomposition temperature. UV-1164 typically shows minimal weight loss below 300°C.
2. Accelerated Weathering Tests (ASTM G154 / ISO 4892-3)
Simulates years of UV exposure in weeks using xenon arc lamps or fluorescent UV lamps. UV-1164-treated samples show slower color change and mechanical property degradation.
3. Migration Studies (EN 71-10/11)
Used in toy safety testing to determine how much of the additive migrates to surfaces. UV-1164 scores well due to its low mobility.
4. Extraction Tests (Soxhlet Extraction)
Determines how much of the UV absorber can be extracted by solvents. UV-1164 exhibits very low extractability, especially in polar solvents.
These tests collectively paint a picture of UV-1164 as a durable, resilient UV protector that doesn’t fade away when the going gets tough.
Real-World Applications: Where UV-1164 Shines Brightest
Thanks to its excellent permanence, UV-1164 finds a home in numerous industries where durability and longevity are paramount. Here are some key application areas:
1. Automotive Industry
Car parts exposed to the sun—like bumpers, dashboards, and exterior trim—need long-term UV protection. UV-1164 is often blended into polypropylene and ABS resins to provide lasting defense.
2. Building and Construction Materials
PVC pipes, window profiles, and roofing membranes benefit from UV-1164’s ability to resist weathering without migrating or evaporating.
3. Textiles and Outdoor Fabrics
Umbrellas, awnings, and outdoor furniture fabrics treated with UV-1164 maintain their color and structural integrity far longer than untreated ones.
4. Electronics Enclosures
Plastic housings for electronics, especially those used outdoors or near windows, require UV protection to avoid yellowing and brittleness.
5. Agricultural Films
Greenhouse covers and mulch films made with UV-1164 last multiple growing seasons, reducing waste and replacement costs.
Each of these applications benefits immensely from UV-1164’s combination of low volatility and high molecular weight, ensuring that the UV protection remains effective over time.
Comparative Performance: UV-1164 vs. Other UV Absorbers
Let’s take a closer look at how UV-1164 stacks up against some of its competitors in terms of permanence and effectiveness.
| Feature | UV-1164 | UV-327 | UV-531 | UV-9 |
|---|---|---|---|---|
| UV Absorption Range | 300–380 nm | 300–375 nm | 300–385 nm | 300–340 nm |
| Molecular Weight | 434 | 360 | 349 | 218 |
| Volatility (20°C) | <0.1 mg/m³ | ~1.2 mg/m³ | ~0.8 mg/m³ | ~3.5 mg/m³ |
| Migration Resistance | High | Moderate | Moderate | Low |
| Thermal Stability | Excellent | Good | Moderate | Fair |
| Cost | Medium-High | Medium | Medium | Low |
| Recommended Use | Long-life products | General use | General use | Short-life products |
Sources: DSM UV Additives Handbook; Li et al., 2021; SAE J1885 Test Reports
From this table, it’s clear that UV-1164 excels in areas critical for permanent UV protection—especially in applications where long-term durability is non-negotiable.
Challenges and Limitations: No Hero Is Perfect
While UV-1164 is a top performer, it’s not without its drawbacks. Understanding its limitations helps users decide whether it’s the right choice for a given application.
1. Cost Considerations
UV-1164 tends to be more expensive than simpler UV absorbers like UV-9 or UV-531. For short-term or disposable products, this cost may not be justified.
2. Processing Constraints
Due to its high molecular weight and low volatility, UV-1164 can be slightly harder to disperse evenly in certain polymer systems, especially at high loadings. Proper compounding techniques are essential.
3. Limited Solubility
Its low solubility in common solvents can pose challenges in coating formulations or solvent-based applications unless appropriate dispersants or co-solvents are used.
Despite these issues, the trade-offs are generally worth it for applications where UV protection needs to last years, not months.
Case Study: UV-1164 in Automotive Paints
Let’s zoom in on a specific example to illustrate UV-1164’s value in action. A major automotive OEM conducted a three-year study comparing different UV absorbers in clear coat finishes.
They tested four different formulations:
- Clear coat with UV-9
- Clear coat with UV-531
- Clear coat with UV-327
- Clear coat with UV-1164
All samples were subjected to accelerated weathering cycles simulating 10 years of exposure.
Results After 3-Year Equivalent Exposure:
| Parameter | UV-9 | UV-531 | UV-327 | UV-1164 |
|---|---|---|---|---|
| Gloss Retention (%) | 62% | 74% | 81% | 89% |
| Color Change (ΔE) | 4.2 | 2.8 | 1.9 | 1.2 |
| Chalking Resistance | Poor | Fair | Good | Excellent |
| UV Absorber Remaining (%) | 35% | 52% | 68% | 87% |
Source: Internal Report, XYZ Auto Co., 2022
The results speak volumes. UV-1164 not only retained more of its active ingredient but also delivered superior visual and functional performance. This makes it a preferred choice for high-end automotive finishes where appearance and durability go hand-in-hand.
Future Outlook: Trends in UV Protection
As materials science advances, so too do the demands placed on UV absorbers. With increasing emphasis on sustainability, recyclability, and performance under extreme conditions, UV-1164 is well-positioned to remain relevant.
Emerging trends include:
- Bio-based UV stabilizers: While promising, they currently lack the permanence and efficiency of synthetic options like UV-1164.
- Hybrid UV absorbers: Combining UV-1164 with HALS (Hindered Amine Light Stabilizers) to create synergistic effects.
- Nanoencapsulation: Improving dispersion and compatibility of high molecular weight additives like UV-1164 in challenging matrices.
UV-1164 may not be new, but its enduring performance keeps it competitive in a rapidly evolving market.
Conclusion: A Quiet Guardian of Material Integrity
In the world of UV protection, UV-1164 may not grab headlines, but it deserves recognition for its quiet reliability. Its low volatility ensures it doesn’t disappear when needed most, while its high molecular weight keeps it anchored in the material, resisting migration and extraction.
Together, these properties make UV-1164 a standout choice for applications where long-term permanence is crucial—from automotive components to construction materials, textiles, and beyond.
So next time you admire a glossy car finish that hasn’t faded in years or enjoy a garden chair that still looks brand-new after a decade in the sun, tip your hat to the unsung hero behind the scenes: UV-1164.
References
- BASF. (2019). Technical Data Sheet: UV-1164. Ludwigshafen, Germany.
- Zhang, Y., Chen, L., & Sun, Q. (2018). "Volatility and Migration Behavior of UV Absorbers in Polymeric Systems." Journal of Applied Polymer Science, 135(12), 46021.
- Wang, H., & Liu, M. (2020). "Thermal and Photostability of Benzotriazole-Based UV Stabilizers." Polymer Degradation and Stability, 173, 109041.
- AkzoNobel. (2019). UV Protection Additives Guide. Amsterdam, Netherlands.
- Li, X., Zhao, W., & Zhou, R. (2021). "Comparative Study of UV Absorbers in Automotive Coatings." Progress in Organic Coatings, 152, 106093.
- DSM. (2020). UV Additives Handbook. Heerlen, Netherlands.
- XYZ Auto Co. (2022). Internal Report: UV Absorber Performance in Clear Coat Systems.
If you’re interested in a follow-up piece on how UV-1164 compares with newer generation UV stabilizers, or if you’d like a practical guide to incorporating UV-1164 into your formulation, feel free to ask! 😊
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