Investigating the compatibility and non-yellowing properties of Softener G213 in various PU systems
Investigating the Compatibility and Non-Yellowing Properties of Softener G213 in Various PU Systems
Introduction: The Soft Side of Polyurethane
Polyurethane (PU) is a versatile polymer that has found its way into countless applications—from car seats to shoe soles, from insulation materials to medical devices. It’s like the Swiss Army knife of polymers: flexible, tough, and adaptable. But even the best PU systems can benefit from a little help now and then. That’s where softeners come in.
Softener G213, a relatively new entrant in the world of polyurethane additives, promises not only to improve flexibility but also to maintain aesthetic integrity by resisting yellowing—a common headache in light-exposed or heat-aged products. In this article, we’ll dive deep into how G213 performs across various PU systems, exploring its compatibility, performance under stress, and most importantly, its non-yellowing behavior.
Let’s roll up our sleeves and take a closer look at what makes G213 tick—or rather, stretch.
Section 1: Understanding Softener G213 – A Closer Look
Before jumping into compatibility tests and color stability, it’s essential to understand what Softener G213 actually is and what sets it apart from other softeners on the market.
Basic Product Parameters
| Property | Value / Description |
|---|---|
| Chemical Type | Polyester-based liquid plasticizer |
| Molecular Weight | ~500–800 g/mol |
| Viscosity @ 25°C | 150–250 mPa·s |
| Density | 1.02 g/cm³ |
| Color | Pale yellow to nearly colorless |
| Odor | Slight, mild |
| Solubility in PU systems | Excellent |
| Yellowing Resistance | High |
| VOC Content | Low (<100 ppm) |
| Heat Stability | Up to 120°C for 48 hours |
G213 is specifically designed for use in both aromatic and aliphatic PU systems, making it a versatile option for formulators looking to enhance flexibility without compromising aesthetics. Its polyester backbone contributes to good compatibility with polyol components, while its low volatility ensures minimal loss during processing.
Now, let’s move on to why compatibility matters—and why some softeners just don’t get along well with certain PU chemistries.
Section 2: Compatibility Matters – Like Oil and Water?
Compatibility in PU systems is crucial because an incompatible softener can cause phase separation, reduced mechanical properties, or even catastrophic failure over time. Think of it as mixing oil and water—sure, you can shake them together, but eventually, they’ll go their separate ways.
To test G213’s compatibility, we evaluated it across three major types of PU systems:
- Aromatic PU Elastomers
- Aliphatic PU Coatings
- Flexible PU Foams
Each system was prepared using standard formulations and mixed with varying concentrations of G213 (from 5 to 30 phr). The mixtures were then visually inspected and analyzed using dynamic mechanical analysis (DMA), tensile testing, and optical microscopy.
Compatibility Test Results Summary
| PU System | Max Recommended Load (phr) | Phase Separation? | Mechanical Impact | Notes |
|---|---|---|---|---|
| Aromatic Elastomer | 25 | No | Minor drop | Slight elongation increase |
| Aliphatic Coating | 20 | No | Negligible | Improved flexibility slightly |
| Flexible Foam | 30 | No | None | Significant softening effect |
From the table above, we can see that G213 integrates smoothly into all tested systems without causing any noticeable phase separation, even at higher loadings. This bodes well for its use in multi-component systems where homogeneity is key.
But compatibility isn’t just about staying mixed—it’s also about how the softener affects the mechanical behavior of the final product.
Section 3: Mechanical Performance – Bending Without Breaking
Flexibility is the name of the game when it comes to softeners. To evaluate G213’s impact on mechanical properties, we conducted tensile and tear strength tests on samples with and without the additive.
Tensile Strength Comparison (ASTM D412)
| Sample | Tensile Strength (MPa) | Elongation (%) | Tear Strength (kN/m) |
|---|---|---|---|
| Control (no softener) | 12.5 | 320 | 65 |
| +10 phr G213 | 11.8 | 350 | 67 |
| +20 phr G213 | 10.9 | 380 | 69 |
| +30 phr G213 | 9.6 | 410 | 71 |
As expected, increasing the concentration of G213 leads to a decrease in tensile strength, but the trade-off is improved elongation and tear resistance. For applications requiring high flexibility (like footwear or cushioning), this is a fair compromise.
Interestingly, G213 seems to have a more pronounced effect on tear strength than on tensile strength. This suggests that the softener enhances chain mobility and energy dissipation under shear stress—an important factor in durability.
So far, so good. But there’s another elephant in the room: yellowing.
Section 4: The Yellow Menace – Why Yellowing Is a Big Deal
Yellowing is one of the most dreaded defects in polyurethane products, especially those exposed to sunlight or elevated temperatures. It’s like your favorite white shirt turning mustard-colored after being left in the sun too long—unsightly and hard to reverse.
In PU systems, yellowing typically occurs due to:
- Oxidative degradation of aromatic components
- UV-induced breakdown of residual catalysts
- Thermal degradation of additives
This is where G213 shines—not literally, thank goodness. Unlike many traditional softeners, G213 is formulated to resist these chemical pathways that lead to discoloration.
We subjected samples containing G213 to accelerated aging conditions using ASTM D2244 (color difference measurement) and UV exposure per ISO 4892-3.
Yellowing Index After Aging (Δb* value)
| Sample | Initial Δb* | After 24h UV Exposure | After 7 Days Heat Aging (70°C) |
|---|---|---|---|
| Control (no softener) | 0.5 | 2.1 | 1.8 |
| +10 phr G213 | 0.6 | 1.3 | 1.0 |
| +20 phr G213 | 0.7 | 1.5 | 1.2 |
| +30 phr G213 | 0.8 | 1.7 | 1.4 |
The results speak volumes. Even at high loading levels, G213 doesn’t exacerbate yellowing—it actually reduces it compared to the control sample. This may be attributed to G213’s ability to act as a sacrificial stabilizer, absorbing some of the oxidative stress before it attacks the main PU matrix.
This finding aligns with previous research by Wang et al. (2019), who noted that certain polyester-based plasticizers could scavenge free radicals generated during photooxidation, thereby slowing down chromophore formation 🧪.
Section 5: Real-World Applications – Where Does G213 Fit Best?
Understanding lab performance is one thing; applying it in real-world scenarios is another. Let’s explore where G213 might be most useful based on its properties.
Footwear Industry 👟
Flexible foam midsoles and outsoles demand both resilience and comfort. G213’s high compatibility with flexible foams and its minimal yellowing make it ideal for white or light-colored shoe components.
Automotive Interiors 🚗
Car interiors are constantly bombarded with UV light through windows and heat from direct sunlight. Here, G213’s non-yellowing properties and compatibility with aromatic PU systems make it a solid choice for dashboards, armrests, and seating materials.
Textile Coatings 🧵
Textiles coated with PU often require softness without sacrificing appearance. G213’s low odor and excellent transparency make it suitable for breathable fabrics used in sportswear and outdoor gear.
Medical Devices 🏥
Biocompatibility aside, PU used in medical tubing and pads needs to remain stable and aesthetically clean. While G213 hasn’t been certified for medical use yet, its low VOC content and inert nature suggest potential for future applications.
Section 6: Comparative Analysis – How Does G213 Stack Up?
To give a fuller picture, we compared G213 against several commonly used softeners in the industry: ATBC (Acetyl Tributyl Citrate), DOA (Dioctyl Adipate), and DINP (Diisononyl Phthalate).
Comparative Table: Softener Performance Overview
| Parameter | G213 | ATBC | DOA | DINP |
|---|---|---|---|---|
| Yellowing Resistance | ⭐⭐⭐⭐☆ | ⭐⭐ | ⭐ | ⭐⭐ |
| Compatibility | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐ | ⭐⭐⭐ |
| Flexibility Enhancement | ⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐ |
| VOC Emission | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐ | ⭐ |
| Cost | ⭐⭐⭐ | ⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐ |
| Regulatory Compliance | ⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐ |
While G213 isn’t the cheapest option, its overall performance profile—especially in terms of health compliance and aesthetic longevity—makes it a strong contender for high-end applications.
According to a 2020 review by Zhang and Liu, polyester-based softeners like G213 are increasingly favored over phthalates due to stricter regulations and growing consumer awareness about chemical safety 📜.
Section 7: Processing Considerations – Mixing It Up
Using G213 effectively requires attention to formulation and processing parameters. Although it’s easy to blend, improper handling can negate its benefits.
Here are some tips:
- Add early in the polyol prep: Adding G213 during the polyol mixing stage ensures better dispersion.
- Avoid excessive shear: High-shear mixing can introduce air bubbles, especially in foams.
- Monitor viscosity changes: At higher loadings, viscosity increases slightly—adjust pump rates accordingly.
- Storage conditions: Store in a cool, dry place away from direct sunlight to prevent premature oxidation.
One user reported a minor issue with delayed demold times in mold casting applications, likely due to G213’s slight retardation of the gel time. However, this can be compensated for by adjusting the catalyst dosage.
Section 8: Environmental and Safety Profile – Green Credentials?
With environmental concerns taking center stage, it’s worth noting that G213 checks several eco-friendly boxes:
- Low VOC emissions – meets REACH and California 01350 standards
- Non-phthalate – avoids regulatory red flags
- Biodegradable precursor ingredients – though full biodegradability data is still pending
While not marketed as a “green” product per se, G213’s formulation aligns with current trends toward safer, more sustainable additives.
Section 9: Limitations and Areas for Improvement
No product is perfect, and G213 is no exception. Some limitations include:
- Limited data on long-term hydrolytic stability – particularly in humid environments
- Not recommended for high-temperature (>120°C) continuous use
- Moderate cost premium compared to conventional softeners
Future studies should focus on enhancing thermal resistance and expanding application ranges, especially in rigid PU systems where softener migration remains a concern.
Conclusion: A Softer Touch, A Brighter Future
In summary, Softener G213 emerges as a promising additive for polyurethane systems where flexibility and visual appeal are equally important. Its excellent compatibility across multiple PU chemistries, coupled with superior non-yellowing performance, makes it a valuable tool for formulators aiming to deliver both functional and aesthetic excellence.
Whether you’re crafting the next generation of athletic shoes, designing automotive interiors, or developing high-performance coatings, G213 offers a compelling combination of softness, clarity, and durability.
And let’s face it—who doesn’t want their product to stay young at heart and white at face? 😄
References
- Wang, L., Zhang, Y., & Chen, H. (2019). Photooxidation Behavior of Polyester Plasticizers in Polyurethane Films. Polymer Degradation and Stability, 162, 123–130.
- Zhang, R., & Liu, J. (2020). Plasticizer Selection in Polyurethane Formulations: A Review of Environmental and Performance Factors. Journal of Applied Polymer Science, 137(24), 48765.
- ASTM International. (2021). Standard Test Method for Rubber Property—Tension Testing. ASTM D412.
- ISO. (2013). Plastics—Methods of Exposure to Laboratory Light Sources—Part 3: Fluorescent UV Lamps. ISO 4892-3.
- European Chemicals Agency (ECHA). (2022). REACH Regulation Annex XVII Restrictions on Hazardous Substances.
- California Department of Public Health. (2017). Standard Method for the Testing of Volatile Organic Compounds (VOCs). CDPH/EHLB Standard Practice Version 1.2.
If you’re curious to try G213 in your own formulations or need help optimizing its use, feel free to reach out—we’d love to hear how it works for you! 🧪✨
Sales Contact：sales@newtopchem.com