Fluid-assisted injection molded articles and process

摘要

Fluid-assisted injection molding articles and processes for producing the articles are described. In one embodiment, a fluid-assisted injection molded article is formed from a polymeric composition containing a polyethylene terephthalate homopolymer in combination with a polyethylene terephthalate copolymer. The polyethylene terephthalate copolymer may comprise a copolymer of polyethylene terephthalate with isophthalic acid. The polymeric composition can also contain a reinforcing agent, such as glass fibers. Products made in accordance with the present disclosure have shown dramatically improved surface characteristics. In particular, pitting on the surface of the molded article is minimized.

主权项

1. A molded product comprising:
an injection molded article defining an exterior surface having a surface area and an internal fluid-formed hollow cavity, the article being made from a composition containing a polymer mixture and reinforcing fibers or reinforcing fillers, the polymer mixture comprising from about 45% to about 95% by weight of the composition, the polymer mixture comprising a polyethylene terephthalate homopolymer combined with a polyethylene terephthalate copolymer, the polyethylene terephthalate homopolymer and the polyethylene terephthalate copolymer being present in the polymer mixture in a weight ratio of from about 10:90 to about 70:30, the polymer mixture optionally containing another polyester polymer in an amount from 0% to about 25% by weight, the other polyester comprising a polybutylene terephthalate, a polybutylene naphthalate, a polytrimethylene terephthalate, a polypropylene terephthalate or a polycyclohexylene dimethyl terephthalate, the polymer mixture having a melt flow rate at 265° C. and at a 2160 g load of from about 20 g/10 min to about 50 g/10 min, the exterior surface of the article containing pits in an amount less than about 2.5% of the surface area of the exterior surface.