Improving the hydrolytic stability of polyurethane products with Polyether SKC-1900

Improving the Hydrolytic Stability of Polyurethane Products with Polyether SKC-1900

Introduction: A Tale of Two Molecules

Polyurethanes are everywhere. From your mattress to car seats, from industrial rollers to medical devices — these versatile polymers have become a cornerstone of modern material science. But like many great things in life, polyurethanes aren’t without their flaws. One major Achilles’ heel? Hydrolytic degradation.

In humid or high-temperature environments, polyurethanes can fall victim to hydrolysis — a chemical reaction where water molecules break down the polymer chains, leading to softening, cracking, and eventual failure. This is especially problematic for products exposed to harsh conditions over long periods.

Enter Polyether SKC-1900, a game-changing polyol that promises to turn the tide against this age-old nemesis. In this article, we’ll dive into what makes SKC-1900 so special, how it improves the hydrolytic stability of polyurethane products, and why you might want to consider making it part of your formulation arsenal.

The Hydrolysis Problem: Why It Matters

Hydrolysis in polyurethanes typically occurs at the ester linkages found in polyester-based polyols. When water gets involved, those ester bonds start to break down, releasing carboxylic acids and alcohols as byproducts. These breakdown products can further accelerate the degradation process — a classic case of "the more it breaks, the faster it breaks."

This isn’t just an academic concern. Imagine a gasket in an engine compartment that starts degrading after six months because of moisture ingress. Or a foam insulation panel that loses its structural integrity in a tropical climate. The economic and safety implications are real.

So, what’s the solution?

Switching from polyester to polyether-based polyols is one effective way to combat hydrolysis. Polyethers form ether linkages instead of ester ones, which are far less susceptible to water attack. And among polyether polyols, SKC-1900 stands out for its unique structure and performance benefits.

Meet SKC-1900: The Hero We’ve Been Waiting For

Let’s get technical — but not too technical. SKC-1900 is a proprietary polyether polyol developed by SK Chemicals (South Korea), specifically designed for applications requiring high hydrolytic stability and mechanical durability. It belongs to the family of poly(tetramethylene ether glycol) (PTMEG)-based polyols, known for their flexibility and resistance to environmental stressors.

Here’s a quick snapshot of SKC-1900’s key characteristics:

Property	Value
Type	Polyether Polyol
Molecular Weight	~2000 g/mol
Functionality	2
OH Number	56 ± 2 mgKOH/g
Viscosity @ 25°C	250–350 mPa·s
Color (APHA)	≤ 50
Water Content	≤ 0.05%
Acid Number	≤ 0.5 mgKOH/g
Reactivity	Moderate to fast

SKC-1900 is often used in the production of thermoplastic polyurethanes (TPUs), cast elastomers, and flexible foams where long-term durability under humid or aqueous conditions is critical.

How SKC-1900 Fights Hydrolysis: The Science Behind the Shield

The secret lies in the molecular architecture. Unlike polyester polyols, which contain ester (-COO-) groups that are vulnerable to nucleophilic attack by water, SKC-1900 uses ether (-O-) linkages throughout its backbone. Ether bonds are significantly more stable in aqueous environments, meaning they’re less likely to undergo hydrolytic cleavage.

But it’s not just about bond strength — it’s also about molecular mobility. The flexible PTMEG chain in SKC-1900 allows for good segmental motion without compromising chemical resilience. This balance between flexibility and stability makes it ideal for dynamic applications such as automotive parts, footwear soles, and industrial rollers.

To illustrate the difference, let’s take a look at a comparative study conducted by Kim et al. (2021) at Seoul National University. They compared the hydrolytic degradation of TPUs made with SKC-1900 versus a standard polyester polyol (PCL-2000) under accelerated aging conditions (85°C, 95% RH for 720 hours):

Sample	Tensile Strength Retention (%)	Elongation Retention (%)	Mass Loss (%)
PCL-2000	42%	38%	7.2%
SKC-1900	89%	85%	1.1%

As you can see, the SKC-1900-based TPU retained nearly double the tensile and elongation properties while losing far less mass. That’s a clear win for hydrolytic stability.

Formulation Tips: Making the Most of SKC-1900

Using SKC-1900 effectively requires understanding its behavior during synthesis and processing. Here are some practical insights:

1. Reactivity Considerations

SKC-1900 has moderate reactivity with diisocyanates like MDI or TDI. It tends to react slower than conventional polyethers like PTMEG-1000, which means longer demold times or slightly higher catalyst levels may be needed in casting applications.

2. Blending Strategies

For optimal performance, SKC-1900 can be blended with other polyols. Mixing it with aromatic diamines or short-chain diols (e.g., BDO) enhances crosslink density and mechanical performance without sacrificing hydrolytic stability.

3. Processing Temperature

Due to its relatively high viscosity (~300 mPa·s), SKC-1900 should be preheated to around 50–60°C before mixing to ensure uniform dispersion and avoid phase separation.

4. Storage and Handling

Store SKC-1900 in tightly sealed containers under dry conditions. Exposure to moisture can lead to premature hydrolysis even before processing begins.

Real-World Applications: Where SKC-1900 Shines Brightest

Automotive Industry

Car interiors, especially components like steering wheels, shift boots, and seat covers, are constantly exposed to temperature fluctuations and humidity. SKC-1900 helps maintain flexibility and appearance over time.

Footwear

High-performance shoe soles made with SKC-1900-based TPUs offer better cushioning and durability, particularly in wet climates. Brands like Asics and Mizuno have started incorporating similar formulations into their premium lines.

Industrial Rollers and Belts

Conveyor belts and printing rollers in paper mills or textile factories face constant exposure to steam and moisture. SKC-1900 extends service life dramatically compared to traditional materials.

Medical Devices

From catheters to prosthetic liners, biocompatibility and long-term stability are crucial. SKC-1900 meets ISO 10993 standards and resists microbial growth due to its low extractables profile.

Case Study: SKC-1900 in Action – An Industrial Belt Manufacturer’s Journey

A South Korean manufacturer of conveyor belts was experiencing frequent failures in their rubber-polyurethane hybrid products used in rice mills. The problem? Moisture from the grains caused rapid degradation of the urethane layer, leading to costly downtime and replacements.

After switching to a formulation based on SKC-1900, the company saw:

A 300% increase in belt lifespan
60% reduction in maintenance costs
Improved customer satisfaction ratings

The change wasn’t just about chemistry; it was about economics and sustainability.

Comparative Analysis: SKC-1900 vs. Other Polyether Polyols

Let’s put SKC-1900 up against some of its peers in the polyether family. While all polyethers are generally more hydrolytically stable than polyesters, there are differences in performance and application suitability.

Feature	SKC-1900	PTMEG-2000	Polyoxypropylene Glycol (PPG-2000)	Poly(ethylene glycol) (PEG-2000)
Hydrolytic Stability	Excellent	Good	Moderate	Poor
Flexibility	High	High	Medium	Low
Mechanical Strength	Very Good	Good	Fair	Low
Cost	Moderate	High	Low	Moderate
Biodegradability	Low	Low	Medium	High
Processability	Easy	Moderate	Easy	Challenging
Typical Application	Industrial elastomers, footwear, automotive	Spandex, adhesives	Coatings, sealants	Pharmaceuticals, controlled release systems

As shown, SKC-1900 strikes a near-perfect balance between cost, performance, and processability. Its superior hydrolytic stability makes it the go-to choice for demanding applications where longevity is key.

Challenges and Limitations: Not Perfect, But Pretty Close

No material is perfect, and SKC-1900 is no exception. Here are some considerations when using it:

Higher Cost Compared to PPGs: While cheaper than PTMEG-2000, SKC-1900 is still more expensive than commodity polyols like PPG-2000.
Slightly Slower Cure Time: Due to its moderate reactivity, cure cycles may need adjustment.
Limited UV Resistance: Like most polyethers, SKC-1900 is prone to yellowing under prolonged UV exposure unless stabilized.

However, these drawbacks can be mitigated through proper formulation design and the use of stabilizers or antioxidants.

Future Outlook: What Lies Ahead for SKC-1900 and Hydrolytic Stability

As industries continue to demand more from their materials — longer lifespans, reduced waste, and better performance — the importance of hydrolytically stable polyols like SKC-1900 will only grow.

Emerging trends include:

Bio-based Polyethers: Researchers are exploring renewable feedstocks for next-generation polyether polyols. While SKC-1900 is currently petroleum-derived, future versions may incorporate bio-sourced building blocks.
Nanocomposites: Adding nanofillers like silica or clay to SKC-1900-based systems can enhance both mechanical and barrier properties, offering dual protection against hydrolysis and abrasion.
Smart Polyurethanes: Integrating self-healing or responsive functionalities into SKC-1900-based matrices could open new frontiers in adaptive materials.

Conclusion: The Long and Short of It

In the world of polyurethanes, hydrolytic stability is a big deal. Whether you’re designing a shoe sole for marathon runners or a roller for a paper mill, the last thing you want is premature failure due to moisture.

SKC-1900 offers a compelling solution — combining excellent hydrolytic resistance, mechanical strength, and processability. It’s not just another polyether polyol; it’s a strategic choice for engineers and formulators looking to build products that last.

As the old saying goes, “An ounce of prevention is worth a pound of cure.” In the case of polyurethane degradation, SKC-1900 might just be that ounce of prevention you’ve been looking for. 🧪💧💪

References

Kim, J., Lee, H., & Park, S. (2021). Comparative Study of Hydrolytic Degradation in Polyester and Polyether-Based Thermoplastic Polyurethanes. Journal of Applied Polymer Science, 138(12), 49872–49881.
Cho, Y., Kim, D., & Hong, C. (2019). Development and Characterization of Eco-Friendly Polyurethane Elastomers Using Modified Polyether Polyols. Polymer Engineering & Science, 59(S2), E145–E153.
Zhang, L., Wang, X., & Liu, Y. (2020). Recent Advances in Hydrolytic Stability of Polyurethanes: Mechanisms and Strategies. Progress in Polymer Science, 100, 101324.
SK Chemicals Product Data Sheet. (2023). SKC-1900 Polyether Polyol Technical Specifications. Internal Document.
Oh, K., & Rhee, J. (2018). Long-Term Performance Evaluation of Polyurethane Rollers in Industrial Applications. Materials Today: Proceedings, 5(11), 23456–23463.
ASTM D2240-21. Standard Test Method for Rubber Property—Durometer Hardness.
ISO 10993-10:2010. Biological evaluation of medical devices — Part 10: Tests for irritation and skin sensitization.
Han, M., Jeong, H., & Choi, B. (2022). Effect of Chain Extenders on Mechanical and Thermal Properties of SKC-1900-Based Polyurethanes. Macromolecular Research, 30(4), 321–329.
Gupta, R., & Singh, A. (2020). Role of Polyol Structure on Hydrolytic Degradation of Polyurethanes: A Review. Polymer Degradation and Stability, 177, 109145.
Chen, W., Li, Z., & Xu, Q. (2021). Nanocomposite Polyurethanes: Enhancing Barrier and Mechanical Properties for Harsh Environments. Composites Part B: Engineering, 215, 108857.

If you’re working with polyurethanes and care about product longevity, give SKC-1900 a shot. It might just save you a lot of headaches — and a few dollars — down the line.

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