Flame retardant compositions

Claim 2

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.

Claim 3

A cladded substrate according to claim 1 wherein the cladding comprises electrical insulation.

Claim 4

A cladded substrate according to claim 2 wherein the substrate comprises a wire, cable or electrical harness.

Claim 5

A cladded substrate according to claim 1 wherein the cladding provides a seal or mechanical or environmental protection.

Claim 6

A cladded substrate according to claim 4 wherein the substrate comprises a pipe or duct.

Claim 7

A cladded substrate according to claim 1 wherein the cladding is located about the substrate by dimensional recovery thereof.

Claim 8

A cladded substrate according to claim 1 wherein a sealant or adhesive is interposed between the substrate and cladding.

Claim 9

A cladded substrate according to claim 1 wherein the vinyl acetate/alkene copolymer of the cladding has a vinyl acetate content in the range of 60 to 95 weight percent.

Claim 10

A cladded substrate according to claim 8 wherein the vinyl acetate/alkene copolymer of the cladding has a vinyl acetate content in the range of 65 to 85 weight percent.

Claim 11

A cladded substrate according to claim 1 wherein the vinyl acetate/alkene copolymer is a vinyl acetate/ethylene copolymer.

Claim 12

A cladded substrate according to claim 1 wherein the halogen-free inorganic flame retardant is alumina trihydrate.

Claim 13

A cladded substrate according to claim 1 wherein the vinyl acetate/alkene copolymer is present as a blend with a thermoplastic polyalkene.

Claim 14

A cladded substrate according to claim 1 wherein the vinyl acetate/alkene copolymer is present as a blend with an alkene/alkene copolymer.

Claim 15

A cladded substrate according to claim 13 wherein the vinyl acetate/alkene copolymer is present as a blend with a polyethylene or an ethylene/C 3 -C 12 alkene copolymer.

Claim 16

A cladded substrate according to claim 14 wherein the vinyl acetate/alkene copolymer is present as a blend with a linear ethylene/C 3 -C 12 alkene copolymer having a density in the range 0.910 to 0.940 gm/cm 3 at 25° C.

Claim 17

A cladded substrate according to claim 1 wherein the weight ratio of vinyl acetate/alkene copolymer to the other polymer(s) of the blend is in the range 1:0.2 to 4.

Claim 18

A cladded substrate according to claim 16 wherein the weight ratio of vinyl acetate/alkene copolymer to the other polymer(s) of the blend is in the range 1:0.2 to 1.5.

Claim 19

A cladded substrate according to claim 1 wherein the overall amount of vinyl acetate in the blend is at least 30 weight percent.

Claim 20

A cladded substrate according to claim 1 wherein the polymeric composition of the cladding incorporates a coupling agent.

Claim 21

A flame retarded cladding as defined in claim 1 wherein at least part of the surface which is to contact the substrate is coated with sealant or adhesive.

Claim 22

A flame retarded cladding according to claim 20 wherein the coating is a hot-melt adhesive.

Claim 23

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.

Claim 24

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.

Claim 25

A composition according to claim 22 wherein the blend component is a polyethylene or an ethylene/C 3 -C 12 alkene copolymer.

Claim 26

A composition according to claim 23 wherein the blend component is a ethylene/C 3 -C 12 alkene copolymer having a density in the range 0.910 to 0.940 gm/cm 3 at 25° C.

Claim 27

A composition according to claim 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 4.

Claim 28

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.

Claim 29

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.

Claim 30

A composition according to claim 20 wherein the overall amount of vinyl acetate in the blend is at least 30 weight percent.

Claim 31

Heat-recoverable flame retarded cladding formed from the compositions as claimed in claim 20.

Claim 32

A heat-recoverable flame retarded cladding according to claim 28 wherein the weight ratio of vinyl acetate/alkene copolymer to thermoplastic polymer is in the range 1:0.2 to 0.55.

Claim 33

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.

Claim 34

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.