In the field of monofilament for automotive interiors, flame retardancy and long-term stability are core requirements. Our developed low-carboxyl-content flame-retardant copolyester chips exhibit significant advantages in enhancing flame retardant performance by optimizing the polymer structure and reducing side reaction risks.
1. Technical Description
The low carboxyl content flame-retardant copolyester chips used in monofilament applications offer the following advantages:
- Higher Copolymerization Efficiency
The lower carboxyl content reduces the risk of side reactions with flame-retardant monomers (such as CEPPA and DOPO derivatives). This allows for more effective grafting to the polymer main chain without decomposition or volatilization, thereby increasing the effective utilization of the flame-retardant additives. - Superior Thermal Stability and Processing Safety
During the spinning or extrusion process, low-carboxyl content polyester is less prone to degradation, which helps to reduce smoke, yellowing, and gel formation, improving overall processing stability and product appearance. - Enhanced Long-term Stability
The low carboxyl structure reduces the risk of hydrolysis and thermal oxidation degradation, enabling the monofilament to maintain excellent mechanical properties and flame retardant performance in long-term high-temperature and humid environments, making it particularly suitable for the complex usage conditions of automotive interiors.
2. Relationship Between Carboxyl Content and Flame Retardant Performance
| Item | Explanation |
| Effect of Carboxyl Group | The carboxyl group (–COOH) does not possess flame-retardant properties and does not participate in the flame-retardant reaction mechanism. It does not directly enhance flame retardancy. |
| Impact on Processing Thermal Stability | High carboxyl content reduces polyester’s thermal stability, making it more prone to degradation, yellowing, and smoking during processing, which in turn affects the consistency and effectiveness of the flame retardant. |
| Effect on Flame Retardant Dispersibility | Low-carboxyl polyester offers a stable structure, minimizing side reactions and enhancing compatibility with phosphorus-based and nitrogen-based flame retardants, ensuring more uniform dispersal and better flame retardant performance. |
| Impact on Product Longevity | Products with high carboxyl content are prone to hydrolysis and oxidation during prolonged high-temperature use, which reduces flame retardant durability. Low-carboxyl polyester is more stable and is suitable for high-demand applications. |
3. High Carboxyl vs Low Carboxyl Polyester Performance Comparison
| Performance Indicator | High Carboxyl Polyester | Low Carboxyl Polyester |
| Copolymerization Efficiency | Lower, more side reactions | Higher, more stable grafting of flame retardant monomers |
| Thermal Stability | Prone to degradation, higher processing risks | Higher stability, safer processing |
| Flame Retardancy Durability | Tends to age and degrade | Stable and long-lasting flame retardant effect |
| Suitability for Automotive Interiors | Risk of use | High reliability and stability, suitable for high-demand applications |
4. Conclusion
Low-carboxyl flame-retardant copolyester chips are particularly suitable for applications where safety and durability are critical, such as in automotive interiors. Their superior copolymerization stability, thermal processing performance, and long-lasting flame retardancy make them an ideal choice for monofilament manufacturers in high-standard applications.
