Flame retardant compositions
AssigneeRaychem Corporation
InventorRichard S. Skipper
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Abstract
The invention concerns a novel cladded elongate substrate such as a jacketed cable, the cladding being flame retarded and comprising a vinyl acetate/alkene copolymer composition incorporating a halogen-free inorganic flame retardant. The composition is characterized by a high content of vinyl acetate and/or the presence of a polyalkene or alkene/alkene copolymer blended with the vinyl acetate/alkene copolymer.
Claims30
An elongate substrate provided, over at least a part thereof, with a flame retarded cladding, said cladding being formed from a halogen-free polymeric composition which comprises a substantially cross-linked blend of a vinyl acetate/alkene copolymer with a styrene/butadiene rubber, or a thermoplastic polyalkene or alkene/alkene copolymer and incorporates an effective amount of a halogen-free inorganic flame retardant which releases water on heating when subjected to the conditions of ASTM-D-2863, with the provisos that:
- when the vinyl acetate/alkene copolymer is blended with a styrene/butadiene rubber, the vinyl acetate/alkene copolymer has a vinyl acetate content of greater than 55 weight percent, or
- when the vinyl acetate/alkene copolymer is blended with a thermoplastic polyalkene or alkene/alkene copolymer and the blend contains less than 66 weight percent vinyl acetate/alkene copolymer, the blend has an overall vinyl acetate content of at least 18 weight percent, or
- when the vinyl acetate/alkene copolymer is blended with a thermoplastic polyalkene or alkene/alkene copolymer and the blend contains at least 66 weight percent vinyl acetate/alkene copolymer, then the vinyl acetate/alkene copolymer has a vinyl acetate content of greater than 40 weight percent.
A flame retarded halogen-free polymeric composition which comprises a substantially cross-linked blend of vinyl acetate/alkene copolymer with a thermoplastic polyalkene or an alkene/alkene copolymer and incorporates an effective amount of a halogen-free inorganic flame retardant which releases water on heating when subjected to the conditions of ASTM-D-2863, the blend having an overall vinyl acetate content of at least 18 weight percent when the blend contains less than 66 weight percent vinyl acetate/alkene copolymer, and when the blend comprises at least 66 weight percent of vinyl acetate/alkene copolymer, this copolymer has a vinyl acetate content of greater than 40 weight percent.
A composition according to clain 22 wherein the weight ratio of vinyl acetate/alkene copolymer to polyalkene or alkene/alkene copolymer in the blend is in the range 1:0.2 to 1.5.
An elongate substrate provided, over at least a part thereof, with a flame retarded cladding, said cladding being formed from a halogen-free polymeric composition which comprises a substantially cross-linked blend of a vinyl acetate/alkene copolymer with a styrene/butadiene rubber, or a thermoplastic polyalkene or alkene/alkene copolymer and incorporates an effective amount of a halogen-free inorganic flame retardant which releases water on heating when subjected to the conditions of ASTM-D-2863, with the provisos that:
- (i) when the vinyl acetate/alkene copolymer is blended with a styrene/butadiene rubber, the vinyl acetate/alkene copolymer has a vinyl acetate content of greater than 55 weight percent, or
- (ii) when the vinyl acetate/alkene copolymer is blended with a thermoplastic polyalkene or alkene/alkene copolymer and the blend contains less than 66 weight percent vinyl acetate/alkene copolymer, the blend has an overall vinyl acetate content of at least 30 weight percent, or
- (iii) when the vinyl acetate/alkene copolymer is blended with a thermoplastic polyalkene or alkene/alkene copolymer and the blend contains at least 66 weight percent vinyl acetate/alkene copolymer then the vinyl acetate/alkene copolymer has a vinyl acetate content of greater than 40 weight percent.
Dependencies are inferred from the claim text.