IMPROVED NYLON RESINS AND PROCESS

摘要

The disclosures herein relate to a polymer such as nylon 66, having low yellowness and excellent whiteness retention for applications in melt extrusion and injection molding where an increase in molecular weight is not desirable. The polymer is prepared with a phosphorus compound content, e.g., a sodium hypophosphite (SHP) content, in an amount of 150 to 300 ppm by weight. The presence of an "end cap" additive such as one selected from acetic acid, propionic acid, benzoic acid, or succinic acid, added at the start of polymerization, effectively mitigates undesired molecular weight gain.