Flame retarded polyethylene terephthalate compositions with improved drip suppression

Claim 2

A thermoplastic molding composition comprising (a) a flame retarded polyethylene terephthalate having an intrinsic viscosity of at least 0.3 dl/g measured as a 0.5% by weight solution in a 1:1 mixture of phenol and tetrachloroethane at 25° C. and containing at least sufficient flame retardant to display a UL-94 rating at 1/8" of VO, and (b) from 2 to 30%, by weight, of a multiphase composite interpolymer comprising (i) from about 25 to 95 weight percent of a first elastomeric phase polymerized from a monomer system comprising about 75 to 99.8%, by weight, C 1 to C 6 alkylacrylate, 0.1 to 5%, by weight, crosslinking monomer, 0.1 to 5%, by weight, graftlinking monomer, said crosslinking monomer being a polyethylenically unsaturated monomer having a plurality of addition polymerizable reactive groups, all of which polymerize at substantially the same rate of reaction, and said graftlinking monomer being a polyethylenically unsaturated monomer having a plurality of addition polymerizable reactive groups, at least one of which polymerizes at a substantially different rate of polymerization from at least one other of said reactive groups; and (ii) from about 75 to 5 weight percent of a final, rigid thermoplastic phase which is polymerized in the presence of said elastomeric phase and which is free of epoxy groups.

Claim 3

A thermoplastic composition comprising (a) a polyethylene terephthalate having an intrinsic viscosity of at least 0.3 dl/g measured as a 0.5%, by weight, solution in a 1:1 mixture of phenol and tetrachloroethane at 25° C., (b) from 2 to 30%, by weight, based on component (a), of a multiphase composite interpolymer comprising (i) from about 25 to 95 weight percent of a first elastomeric phase polymerized from a monomer system comprising about 75 to 99.8%, by weight, C 1 to C 6 alkylacrylate, 0.1 to 5%, by weight, crosslinking monomer, 0.1 to 5%, by weight, graftlinking monomer, said crosslinking monomer being a polyethylenically unsaturated monomer having a plurality of addition polymerizable reactive groups, all of which polymerize at substantially the same rate of reaction, and said graftlinking monomer being a polyethylenically unsaturated monomer having a plurality of addition polymerizable reactive groups, at least one of which polymerizes at a substantially different rate of polymerization from at least one other of said reactive groups; and (ii) from about 75 to 5 weight percent of a final, rigid thermoplastic phase which is polymerized in the presence of said elastomeric hase and which is free of epoxy groups; (c) from 3 to 20%, by weight, based on component (a) of a fire retardant, and (d) from 0 to 50%, by weight, based on component (a) of glass fibers.

Claim 4

A thermoplastic composition comprising (a) a polyethylene terephthalate having an intrinsic viscosity of at least 0.3 dl/g measured as a 0.5%, by weight, solution in a 1:1 mixture of phenol and tetrachloroethane at 25° C., (b) from 2 to 30%, by weight, based on component (a), of a multiphase composite interpolymer comprising (i) from about 25 to 95 weight percent of a first elastomeric phase polymerized from a monomer system comprising about 75 to 99.8%, by weight, C 1 to C 6 alkylacrylate, 0.1 to 5%, by weight, crosslinking monomer, 0.1 to 5%, by weight, graftlinking monomer, said crosslinking monomer being a polyethylenically unsaturated monomer having a plurality of addition polymerizable reactive groups, all of which polymerize at substantially the same rate of reaction, and said graftlinking monomer being a polyethylenically unsaturated monomer having a plurality of addition polymerizable reactive groups, at least one of which polymerizes at a substantially different rate of polymerization from at least one other of said reactive groups; and (ii) from about 75 to 5 weight percent of a final, rigid thermoplastic phase which is polymerized in the presence of said elastomeric hase and which is free of epoxy groups; (c) from 3 to 20%, by weight, based on component (a) of a fire retardant, and (d) from 0 to 50%, by weight, based on component (a) of glass fibers.

Claim 5

The composition of claim 1, wherein at least sufficient composite interpolymer is present to provide a passing rating at 0.250 inches in the UL-94-5V test.

Claim 6

The composition of claim 1, wherein at least sufficient composite interpolymer and glass fibers are present to provide a passing rating at 0.062 inches in the UL-94-5V test.

Claim 7

The composition of claim 2, wherein the flame retardant includes an organic compound containing at least one imide group and having a melting point greater than 240° C.

Claim 8

The composition of claim 2, wherein the composite interpolymer has an allyl methacrylate or diallylmaleate graftlinker and a butylene diacrylate crosslinker.

Claim 9

The composition of claim 6, wherein the composite interpolymer has only two phases, the first phase comprising about 60 to 95%, by weight, of said interpolymer and being polymerized from 95 to 99.8%, by weight, of butyl acrylate, 0.1 to 2.5%, by weight, of butylene diacrylate as a crosslinking agent and 0.1 to 2.5%, by weight, of allyl methacrylate or diallylmaleate as a graftlinking agent and said final phase is polymerized from about 60 to 100%, by weight, of methyl methacrylate.

Claim 10

The composition of claim 1 or 7 comprising (a) 50 to 65 wt % of a polyethylene terephthalate having an intrinsic viscosity of at least 0.5 dl/g, (b) 5 to 20 wt % of the multiphase composite interpolymer, (c) 5 to 15 wt % of a flame retardant, and 20 to 45 wt % of glass fibers.