Micronized particles

This invention relates to low intrinsic viscosity drop, low acetaldehyde, polyesters for producing packaging material such as bottles. More specifically, the polyesters contain additives such as fumed silicon dioxide. In another aspect, this invention relates to certain additives (micronized particles) for the polyesters and for polyamide polymers. The low intrinsic viscosity drop, low acetaldehyde, polyesters and polyamides of the invention typically produce packaging materials such as bottles and fibers. The polyester, generally PET, uses additives such as fumed silicon dioxide. The additives are added in small amounts for achieving the following benefits: (i) lower I.V. (intrinsic viscosity) drop during the injection molding process; (ii) lower levels of acetaldehyde in the resultant preforms/bottles. In another embodiment, micronized particles less than 0.1 micron in size hastens the shift of the higher temperature crystallization peak from 160˜170° C. to 130˜150° C. for virgin and freshly produced polyethylene terephthalate polymer chips and hence shortening or eliminating the expensive relaxation/storage time before other processing. This thereby avoids distorted or fused chips in the finished product.