Heat stabilized polyalkylene terephthalate resin composition

Claim 1

In a molding resin comprising a reinforcing filler and a polyalkylene terephthalate selected from the group consisting of the polymer reaction product of 1,3-propanediol and terephthalic acid or dimethyl terephthalate and the polymer reaction product of 1,4-butanediol and terephthalic acid or dimethyl terephthalate, said polyalkylene terephthalate having an intrinsic viscosity in the range of about 0.4 to about 1.2 deciliters per gram, as measured in an 8 weight percent solution, based on the polymer weight, of orthochlorophenol at 25° C.; the improvement comprising an intimate blend of said molding resin and the combination of stabilizing amounts of additives of each of a. a linear polyamide polymer having a relative viscosity in the range from 35 to 100 b. a thermoplastic phenoxy resin having a repeating structure: ##STR3## and an average molecular weight in a range from about 15,000 to about 75,000 c. an organic phosphonate of the formula: ##STR4## wherein n is 0 or 1 and a. when n is 1, each of R and R 1 is alkyl having from 12 to 24 carbon atoms and each of R 2 and R 3 is alkyl having from 1 to 6 carbon atoms, and R 4 is hydrogen; and b. when n is 0, R 2 , oh and R 3 are fixed, respectively, in the 3, 4 and 5 positions of the benzene ring portion of the benzylphosphonate; each of R and R 1 is alkyl of 14 to 30 carbon atoms, R 2 is alkyl of from 1 to 6 carbon atoms, R 3 is tertiary-butyl, and R 4 is a member selected from the group consisting of hydrogen and methyl.