Foamable polyester composition

Claim 2

A foamable thermoplastic injection moldable composition consisting of in admixture: (a) a poly(1,4-butylene terephthalate) resin or copolyesters thereof; (b) a filler selected from the group consisting of fibrous glass or a mineral or mixtures thereof in an amount of from about 5 to about 50 weight percent; and, (c) a foaming agent in amounts of from about 0.02 to about 5.0 weight percent based on the weight of the resin selected from the group consisting of dinitrosopentamethylene tetramine, p-toluene sulfonyl semicarbazide, 5-phenyltetrazole, calcium oxalate and trihydrazino-s-triazine.

Claim 3

The composition as defined in claim 1 wherein said polyester is poly(1,4-butylene terephthalate).

Claim 4

The composition as defined in claim 1 wherein the polyester resin contains units providing branching sites and derived from compounds containing at least three ester forming groups.

Claim 5

The composition as defined in claim 1 wherein the fibrous glass filler comprises finely divided fibrous glass filaments.

Claim 6

The composition as defined in claim 1 wherein the mineral filler is talc.

Claim 7

The composition as defined in claim 1 wherein the mineral filler is asbestos.

Claim 8

The composition as defined in claim 1 wherein the mineral filler is Wollastonite.

Claim 9

The composition as defined in claim 1 wherein the foaming agent is present in the amount of from about 0.02 to about 2.0 weight percent based on the weight of resin.

Claim 10

A flame retardant foamable thermoplastic composition consisting of in admixture: (a) a poly(1,4-butylene terephthalate) resin or copolyester thereof; (b) a filler selected from the group consisting of fibrous glass or a mineral or mixtures thereof in an amount of from about 5 to about 50 weight percent; (c) a foaming agent in amounts of from about 0.02 to about 5.0 weight percent based on the weight of the resin selected from the group consisting of dinitrosopentamethylene tetramine, p-toluene sulfonyl semicarbazide, 5-phenyltetrazole, calcium oxalate and trihydrazino-s-triazine; and, (d) a flame retardant additive in a minor proportion but in an amount at least sufficient to render the polyester resin flame retardant, said flame retardant additive selected from the group consisting of (1) a low molecular weight polymer of a carbonate of a halogenated dihydric phenol, (2) a copolycarbonate of a halogen substituted dihydric phenol and a dihydric phenol, (3) a halogen-containing compound, (4) mixtures of either (1), (2) or (3) above with antimony oxide, (5) elemental phosphorus or a phosphorus compound, (6) a halogen-containing compound in admixture with a phosphorus compound, and (7) a compound containing phosphorus-nitrogen bonds.

Claim 11

A flame retardant foamable thermoplastic composition consisting of in admixture: (a) a poly(1,4-butylene terephthalate) resin or copolyester thereof; (b) a filler selected from the group consisting of fibrous glass or a mineral or mixtures thereof in an amount of from about 5 to about 50 weight percent; (c) a foaming agent in amounts of from about 0.02 to about 5.0 weight percent based on the weight of the resin selected from the group consisting of dinitrosopentamethylene tetramine, p-toluene sulfonyl semicarbazide, 5-phenyltetrazole, calcium oxalate and trihydrazino-s-triazine; and, (d) a flame retardant additive in a minor proportion but in an amount at least sufficient to render the polyester resin flame retardant, said flame retardant additive selected from the group consisting of (1) a low molecular weight polymer of a carbonate of a halogenated dihydric phenol, (2) a copolycarbonate of a halogen substituted dihydric phenol and a dihydric phenol, (3) a halogen-containing compound, (4) mixtures of either (1), (2) or (3) above with antimony oxide, (5) elemental phosphorus or a phosphorus compound, (6) a halogen-containing compound in admixture with a phosphorus compound, and (7) a compound containing phosphorus-nitrogen bonds.

Claim 12

A composition as defined in claim 9 wherein said flame retardant additive is selected from the group consisting of elemental phosphorus; organic phosphonic acids, phosphonates, phosphinates, phosphonites, phosphinites, phosphine oxides, phosphines, phosphites, phosphates and mixtures of any of the foregoing.

Claim 13

A flame retardant composition as defined in claim 9 wherein said flame retardant additive is either (a) a low molecular weight polymer of a carbonate of a halogenated dihydric phenol, said polymer containing from 2 to 10 repeating units of the formula ##STR6## wherein R 1 and R 2 are hydrogen, (lower) alkyl or phenyl, X 1 an X 2 are bromo or chloro and m and r are from 1 to 4, said polymer having low volatility when heated above about 200° C., and a softening point of less than about 300° C., or (b) a combination of said polymer (a) and antimony oxide.

Claim 14

A flame retardant composition as defined in claim 11 wherein said low molecular weight polymer (a) is of the formula ##STR7## wherein the average number of repeating units, n, is from about 3 to 7, and the softening point of said polymer is in the range of from 200° to 260° C.

Claim 15

A flame retardant composition as defined in claim 9 wherein said flame retardant additive is either (a) a copolycarbonate which is the reaction product of a halogen substituted dihydric phenol and a dihydric phenol or (b) a combination of said polymer (a) and antimony oxide.

Claim 16

A flame retardant composition as defined in claim 13 wherein said copolycarbonate is the reaction product of a halogenated bisphenol-A and a dihydric phenol.

Claim 17

The composition as defined in claim 9 wherein the fibrous glass filler comprises finely divided fibrous glass filaments.

Claim 18

The composition as defined in claim 9 wherein the mineral filler is talc.

Claim 19

The composition as defined in claim 9 wherein the mineral filler is asbestos.

Claim 20

The composition as defined in claim 9 wherein the mineral filler is Wollastonite.