Poly(vinyl chloride) polyblend containing a crystalline polyester with

Abstract

A polyblend of poly(vinyl chloride) ('PVC') and a copolyester ('CPE') consists essentially of three components in a structure --(MR).sub.x --(MQ).sub.y -- wherein (MR).sub.x represents an ester segment with a repeating unit of mol wt 204 or 220, (MQ).sub.y an ester segment consisting of a residue of a polyester diol, so that the CPE is non-elastomeric and has a m p in the range from above 170.degree. C. to about 220.degree. C. Then the CPE provides a limited plasticizing function in PVC when the CPE is used in the range from about 30 to about 70 parts by wt based on 100 parts of the polyblend. The lack of a typical plasticizing function is evidenced by a relatively flat modulus curve, preferably one having a slope less than 1.2.times.10.sup.5 psi per unit weight of PVC in the polyblend. A glass reinforced composite of from about 30 to 70 parts by wt PVC and from 30 to about 50 parts by wt of CPE provides a HDT which is greater than might be expected by directly proportioning the effect of the glass fibers in reinforced PVC, and reinforced CPE; the tensile strength of the reinforced composite is greater than 10,000 psi. The crystallinity of the CPE is such that it has essentially no extensibility, a flexural modulus of 3.8.+-..times.10.sup.5 psi and limited miscibility in the PVC. The limited miscibility is responsible for the unique morphology of the polyblend.