Polymer composition

Claim 2

A crosslinkable composition comprising a silyl modified ethylene (co) polymer and a phosphorus or antimony compound containing at least one X-R group wherein X represents the phosphorus or antimony, R is a hydrogen atom or is an organic substituent which is bonded to atom X via a carbon or oxygen atom and wherein X is in the trivalent or pentavalent state and further comprising a silanol condensation catalyst.

Claim 3

A composition as claimed in claim 1 wherein the silyl modified ethylene (co) polymer is the product of copolymerising monomeric material comprising ethylene together with one or more alpha-olefins, vinyl esters, alkyl methacrylates, unsaturated nitriles or unsaturated ethers with an unsaturated silane compound having hydrolysable silane groups.

Claim 4

A composition as claimed in claim 1 wherein the silyl modified ethylene (co) polymer is a graft polymer prepared by grafting an unsaturated silane compound having hydrolysable silane groups on to a polyethylene or an ethylene copolymer.

Claim 5

A composition as claimed in claim 1 prepared by grafting an unsaturated silane compound on to polyethylene or on to a copolymer of ethylene in the presence of a free radical polymerisation initiator, the phosphorus or antimony compound and a silanol condensation catalyst.

Claim 6

A composition as claimed in claim 1 wherein the silyl modified ethylene (co) polymer is a graft polymer prepared by silane-grafting on to polyethylene or a copolymer of ethylene with one or more alpha-olefins, vinyl esters, alkyl(meth)acrylates, unsaturated nitriles or unsaturated ethers.

Claim 7

A composition as claimed in claim 2 wherein the silyl modified ethylene (co) polymer is prepared by copolymerising the monomeric material and the unsaturated silane compound under a pressure of 500 to 400 bars and at a temperature in the range 150° to 400° C. in the presence of a free radical initiator.

Claim 8

A composition as claimed in claim 1 wherein the phosphorus compound is an organic phosphite, organic phosphonite, organic phosphine or an organic phosphine oxide.

Claim 9

A composition as claimed in claim 1 wherein the phosphorus compound is a dialkyl phosphite or trialkyl phosphite.

Claim 10

A composition as claimed in claim 1 wherein the silane groups present in the silyl modified polymer are derived from vinyl trimethoxy silane, vinyl triethoxy silane, vinyl tris(methoxy ethoxy)silane or vinyl triacetoxy silane.

Claim 11

A process for insulating wire or cable comprising extrusion coating the composition claimed in claim 1 on to wire or cable and crosslinking the coating by exposure to water, steam or moist air.

Claim 12

A composition as claimed in claim 8 wherein the phosphorus compound is selected from the group consisting of tributyl phosphite, tri-n-hexyl phosphite, tri-iso-octyl phosphite, tri-nonyl phosphite and di-iso-octylphosphite.

Claim 13

A composition as claimed in claim 8 wherein the phosphorus compound is tributyl phosphite.

Claim 14

A composition as claimed in claim 1, wherein the compound is an antimony compound containing at least one X-R group wherein X represents the antimony, R is a hydrogen atom or is an organic substitutent which is bonded to atom X via a carbon or oxygen atom and wherein X is in the trivalent or pentavalent state.

Claim 15

A composition as claimed in claim 13, wherein the antimony compound is triphenyl stibine.

Claim 16

A process for the prepartion of a crosslinkable composition comprising feeding to an extruder (a) organic polymer comprising polyethylene or a copolymer of ethylene with up to 40% by weight of one or more alpha-olefins, vinyl ethers, vinyl esters, alkyl(meth) acrylates or unsaturated nitriles, (b) 0.1-10 weight %, based on said organic polymer, of an unsaturated silane compound having hydrolysable organic groups, (c) 0.01 to 1 weight %, based on said organic polymer, of an organic peroxy free-radical initiator, (d) 0.001 to 3.0 moles, per mole of unsaturated silane compound, of a silanol condensation catalyst, and (e) 0.001 to 3.0 moles, per mole of unsaturated silane compound, of a phosphorus or antimony compound containing at least one X-R group wherein X represents the phosphorus or antimony, R is a hydrogen atom or is an organic substituent which is bonded to atom X via a carbon or oxygen atom and wherein X is in the trivalent or pentavalent state, under conditions such that the mixture forms a homogeneous melt and the unsaturated silane compound becomes grafted to the organic polymer.

Claim 17

A process for the prepartion of a crosslinkable composition comprising feeding to an extruder (a) organic polymer comprising polyethylene or a copolymer of ethylene with up to 40% by weight of one or more alpha-olefins, vinyl ethers, vinyl esters, alkyl(meth) acrylates or unsaturated nitriles, (b) 0.1-10 weight %, based on said organic polymer, of an unsaturated silane compound having hydrolysable organic groups, (c) 0.01 to 1 weight %, based on said organic polymer, of an organic peroxy free-radical initiator, (d) 0.001 to 3.0 moles, per mole of unsaturated silane compound, of a silanol condensation catalyst, and (e) 0.001 to 3.0 moles, per mole of unsaturated silane compound, of a phosphorus or antimony compound containing at least one X-R group wherein X represents the phosphorus or antimony, R is a hydrogen atom or is an organic substituent which is bonded to atom X via a carbon or oxygen atom and wherein X is in the trivalent or pentavalent state, under conditions such that the mixture forms a homogeneous melt and the unsaturated silane compound becomes grafted to the organic polymer.

Claim 18

A process for reducing the tendency to undergo premature crosslinking of a crosslinkable composition comprising a silyl modified ethylene (co) polymer, which process comprises incorporating into said crosslinkable composition, an amount effective to reduce the tendency to undergo premature crosslinking, of a phosphorus compound or an antimony compound, containing at least one X-R group wherein X represents the phosphorus or antimony, R is a hydrogen atom or is an organic substituent which is bonded to atom X via a carbon oxygen atom and wherein X is in the trivalent or pentavalent state, and further comprising a silanol condensation catalyst.

Claim 19

A process for reducing the tendency to undergo premature crosslinking of a crosslinkable composition comprising a silyl modified ethylene (co) polymer, which process comprises incorporating into said crosslinkable composition, an amount effective to reduce the tendency to undergo premature crosslinking, of a phosphorus compound or an antimony compound, containing at least one X-R group wherein X represents the phosphorus or antimony, R is a hydrogen atom or is an organic substituent which is bonded to atom X via a carbon oxygen atom and wherein X is in the trivalent or pentavalent state, and further comprising a silanol condensation catalyst.