Process for crosslinking thermoplastic polymers with silanes employing peroxide blends and the resulting crosslinked thermoplastic polymers

1 - 27 . (canceled)

28 . A crosslinked polyolefin produced by a process comprising:

a) providing a mixture of:

(i) at least one silane possessing an unsaturated organic function;

(ii) at least two free radical initiators, the first initiator having a first half-life temperature and the second initiator having a second half-life temperature being higher than said first half-life temperature;

(iii) at least one thermoplastic polyolefin; and,

b) reacting the mixture of step (a) under reactive mechanical-working conditions and exposure to moisture to provide said crosslinked polyolefin.

29 . The crosslinked polyolefin of claim 28 wherein the thermoplastic polyolefin is at least one polyolefin selected from the group consisting of high-pressure low-density polyethylene, medium/low-pressure high-density polyethylene, low-pressure low-density polyethylene, medium-density polyethylene, an ethylene-a-olefin copolymer, polypropylene, an ethylene-ethyl acrylate copolymer, an ethylene-vinyl acetate copolymer, an ethylene-propylene copolymer, an ethylene-propylene-diene terpolymer, an ethylene-butene copolymer, polymethyl-pentene-1, polybutene, chlorinated polyethylene, an ethylene-vinyl acetate-chlorine terpolymer, and mixtures thereof.

30 . The crosslinked polyolefin of claim 28 wherein the silane possesses the general formula RR′SiY 2 wherein R represents a monovalently olefinically unsaturated hydrocarbon radical, each Y represents a hydrolysable organic radical and R′ represents a Y radical.

31 . The crosslinked polyolefin of claim 30 wherein the R radical is selected from the group consisting of vinyl, allyl, butenyl, cyclohexenyl, cyclopentadienyl, cyclohexadienyl,

32 . The crosslinked polyolefin of claim 30 wherein the group Y represents a hydrolysable organic radical selected from the group consisting of alkoxy radicals, acyloxy radicals, oximato radicals and amino radicals.

33 . The crosslinked polyolefin of claim 30 wherein the silane is vinyl triethoxysilane and/or vinyl trimethoxysilane.

34 . The crosslinked polyolefin of claim 28 wherein the 0.1 hour half-life temperatures of the first free radical initiator is from about 80° to about 160° C.

35 . The crosslinked polyolefin of claim 28 wherein the 0.1 hour half-life temperatures of the first free radical initiator is from about 90° to about 155° C.

36 . The crosslinked polyolefin of claim 28 wherein the 0.1 hour half-life temperature of the second free radical initiator is from about 125° to about 190° C.

37 . The crosslinked polyolefin of claim 28 wherein the 0.1 hour half-life temperature of the second free radical initiator is from about 140° to about 170° C.

38 . The crosslinked polyolefin of claim 34 wherein the first free radical initiator is selected from the group consisting of di(2,4-dichlorobenzoyl) peroxide, tert-butyl peroxypivalate, dilauroyl peroxide, dibenzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, di(tert-butylperoxy)cyclohexane, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxyacetate, tert-butyl peroxybenzoate, di-tert-amyl peroxide, dicumyl peroxide, d i(tert-butyl peroxyisopropyl )benzene and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

39 . The crosslinked polyolefin of claim 36 wherein the second free radical initiator is selected from the group consisting of tert-butyl peroxyacetate, tert-butyl peroxybenzoate, di-tert-amyl peroxide, dicumyl peroxide, di(tert-butyl-peroxyisopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl cumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3 and di-tert-butyl peroxide.

40 . The crosslinked polyolefin of claim 28 wherein mixture (a) further includes at least one additional component selected from the group consisting of catalysts, stabilizers, fillers, antioxidants, processing aids, oils, plasticizers, pigments and lubricants.

41 . The crosslinked polyolefin of claim 40 where catalyst is a metal carboxylate, an organic metal compound, an organic base, or an acid.

42 . The crosslinked polyolefin of claim 41 where metal carboxylate is dibutyltindilaurate, stannous acetate, stannous octoate, lead naphthenate, zinc octoate, iron-2-ethylhexoate, or cobalt naphthenate.

43 . The crosslinked polyolefin of claim 41 where organic metal compound is a titanium ester or a titanium chelate.

44 . The crosslinked polyolefin of claim 43 where a titanium ester or a titanium chelate is a tetrabutyl titanate, tetranonyl titanate, or bis-(acetylacetonyl) di-isopropyl titanate.

45 . The crosslinked polyolefin of claim 41 where an organic base is ethylamine, hexylamine, dibutylamine or piperidine.

46 . The crosslinked polyolefin of claim 41 where an acid is a mineral acid or a fatty acid.