Flame retardant high temperature nylon
View Patent ↗High temperature nylon compounds that are flame retardant using non-halogenated ingredients are disclosed. Polyphenylene ether, or alternatively the combination of polyphenylene ether and bismaleimides, act as synergists with polyphosphonate to achieve a V-0 rating in a UL 94 test at thicknesses of about 3.18 mm or, preferably, about 1.59 mm.
1. A flame retardant high temperature nylon compound, consisting of:
(a) from about 46 to about 70 weight percent, by weight of the compound, of high temperature nylon having a melting point of about 285 ° C., wherein the high temperature nylon is a bio-based polyphthalamide based on PA10T;
(b) from about 10 to about 33 weight percent, by weight of the compound, of polyphosphonate, wherein the polyphosphonate is a homopolymer, polyphosphonate-co-carbonate polymer, or combination thereof;
(c) from about 5 to about 40 weight percent, by weight of the compound, of polyphenylene ether or a combination of the polyphenylene ether and bismaleimide;
(d) about 0.1 weight percent, by weight of the compound, of stabilizer, wherein the stabilizer is a blend of triarylphosphite and sterically hindered phenolic antioxidant; and
(e) about 0.5 weight percent, by weight of the compound, of polytetrafluoroethylene;
wherein either (A) provided that the bismaleimide is not present in combination with the polyphenylene ether, the polyphosphonate and the polyphenylene ether are present in a combined amount of at least about 30 weight percent, by weight of the compound, or (B) provided that the bismaleimide is present in combination with the polyphenylene ether, the polyphosphonate is present in an amount of at least about 20 weight percent, by weight of the compound, and each of the polyphenylene ether and the bismaleimide is present in an amount of at least about 5 weight percent, by weight of the compound;
wherein melamine-based compounds and boric-acid metallic compounds are excluded from the compound; and
wherein the compound, when injection molded and tested at a thickness of 3.18 mm or less, has a UL 94 rating of V- 0.
2. The flame retardant high temperature nylon compound of claim 1 , wherein either (A) provided that the bismaleimide is not present in combination with the polyphenylene ether, the polyphosphonate and the polyphenylene ether are present in a combined amount ranging from about 30 to about 40 weight percent, by weight of the compound, or (B) provided that the bismaleimide is present in combination with the polyphenylene ether, the polyphosphonate is present in an amount of about 20 weight percent, by weight of the compound, and each of the polyphenylene ether and the bismaleimide is present in an amount of about 5 weight percent, by weight of the compound.
3. The flame retardant high temperature nylon compound of claim 1 , wherein the polyphosphonate is a homopolymer having a phosphorous content of greater than about 8 weight percent, a glass transition temperature of at least about 100° C., and a limiting oxygen index of about 50% or higher.