Improvements in or relating to a laminating process

摘要

907,767. Retreading tyres. HERCULES POWDER CO. Nov. 22, 1960 [Dec. 2, 1959], No. 40186/60. Class 144 (2). [Also in Group VIII] In making pneumatic tyres or retreading worn tyres, a tread layer of a cross-linked copolymer of ethylene and propylene is secured to a sulphur-vulcanized natural or synthetic rubber carcass, by interposing between them a layer of a rubbery partly brominated isoolefinpolyolefin interpolymer and subjecting the assembly to heat and pressure to vulcanize the interpolymer and copolymer. The rubber may be a polymer of at least one compound selected from butadiene, methyl butadiene, di-methyl butadiene, isoprene, pentadiene, and chloroprene, also copolymers of such conjugated diolefins with other unsaturated organic compounds such as styrene, acrylonitrile, and isobutylene. The middle layer, which may be a preformed sheet, or a cement, or both, may be an interpolymer of an iso-olefin containing from 4 to 8 carbon atoms such as iso-butylene, 3- methyl-butene-1, 4-methyl pentene-1, and an aliphatic conjugated polyolefin of from 4 to 18 carbon atoms, e.g. butadiene 1 : 3, isoprene, 2.4- dimethyl butadiene-1.3, dimethallyl, 2-methyl hexadiene-1,5, cyclo-hexadiene, 1-vinyl cyclobutene-2, dipentene, 2.6-dimethyl-4-methyleneheptadiene-2.5, myrcene, ocimene, fulvene, 6.6-diphenyl fulvene, 1,3,3-trimethyl-6-vinylcyclohexadiene 2.4, 6.6-vinyl methyl fulvene. The bromine content of the interpolymer is above 0.5% by weight but below that which' corresponds to complete saturation of the olefine bonds. In addition, the partially brominated interpolymers may be vulcanized in the absence of sulphur, with bivalent metal oxides such as zinc oxide. The cross-linking agent for the copolymer may be an organic peroxide, e.g. di-benzyl peroxide, bis-(α,α-dimethyl benzyl) peroxide, bis-(α,α-di-isopropyl naphthyl methyl) peroxide, t-butyl (penta methyl ethyl) peroxide, di-(tri-ethyl methyl) peroxide, benzoyl peroxide, t-butyl perbenzoate, ethyl percamphorate, di-tbutyl peroxide, benzoperacid, t-butyl-hydroperoxide, p-menthyl (α,α-methyl benzyl) peroxide, and pinanyl (α,α-di-methyl benzyl) peroxide. In addition to the peroxide vulcanizing agents other than auxiliary agents may be used, e.g. sulphur, red lead, and quinone dioxime. The cement mentioned above may be a solution or dispersion in an inert organic solvent such as gasoline, toluene, chlorobenzene, hexane, heptane, trichloroethane and carbon tetrachloride. Specifications 810,023, 810,024, 856,733, 856,736 and 856,737 are referred to.