Additive Improves Melt Flow for PET, PBT and PET/PBT Alloys

A series of melt flow improver additives specifically designed for polyester applications said to outperform traditional lubricants such as CBT, EBS, silicone and Montan wax is newly available from CAI Performance Additives, the sole distributor of high-performance additives produced by China’s Starbetter Chemical Materials.

ST-PA229C can be used by processors as a multifunctional lubricant and dispersant in injection molded PET, PBT, and PET/PBT alloys, including applications such as electrical connectors. Its benefits include increased melt flow index, increased elongation, improved dispersion, improved compatibility, and increased loading content. 

ST-PA229C can also be used as a crystallization acceleration agent in PET. One of its unique benefits is the ability to widen the temperature range where PET crystallization begins. This can lead to reduced cycle times and energy savings during sheet film production and injection molding. The relatively high glass-transition temperature (typically Tg of 80°C/176°F) for PET means the resin can be prone to setting-up without appropriate crystals forming. This can degrade the product performance, explains CAI’s CEO Richard Marshall. “When a PET compound is injected into the mold, and the temperature drops below 80°C, even if the PET has not yet completed crystallization process, the PET molecular chain segments begin to be unable to move, resulting in the inability to complete crystallization.”