Patent GB-840208-A (GB)
Title: Improvements in or relating to laminating processes
IPC: B32B27/00
Filed: 1958-07-29
Abstract: A laminating process comprises heating a layer of normally solid polyethylene or copolymer of ethylene and propylene containing up to 70 mol. per cent of the latter in contact with a vulcanizable composition of natural or synthetic rubber in the presence at the interface of a peroxide of the formula <FORM:0840208/IV(a)/1> wherein R1 is an aryl group, R6 is hydrogen, alkyl or aryl, and R2, R3, R4 and R5 are hydrogen or alkyl groups of less than four carbon atoms. The synthetic rubber may be a polymer of a conjugated diolefine or of chloroprene or a rubbery copolymer of a conjugated diolefine with another unsaturated compound, e.g. styrene, acrylonitrile or isobutylene.  The copolymer of ethylene and propylene may contain one or more additional unsaturated compounds copolymerizable therewith, e.g. butadiene, isoprene, dipentene or allo-ocimene in amount generally not exceeding 40% by weight.  The peroxide may be symmetrical or nonsymmetrical, numerous examples are given, and may be incorporated in either layer or may be coated on the surface of one or both layers, e.g. in solution in acetone.  A mixture of peroxides may be used.  The laminate may be maintained under light pressure during the bonding.  The polyethylene or copolymer may be employed in the form of film, powder or flake, the two latter forms fusing during the heating step to form a coherent coating.  In an example, powdered high-density polyethylene is treated with an acetone solution of bis-(a ,a -dimethyl-benzyl)-peroxide, dried and applied, as a slurry in water containing the sodium salt of carboxymethyl cellulose to a synthetic rubber (GRS) mix containing the peroxide. The slab is then heated in a mould.  Specifications 471,590, 721,046, 748,583, 748,632, 748,634, 753,349, 799,392, 799,823, 801,031, 804,641, 810,023, U.S.A.  Specifications 2,658,059, 2,692,257, 2,692,258.  2,692,259, 2,692,295, 2,700,663, 2,702,288, 2,717,889, 2,728,755 and Belgian Specification 530,617 are referred to.ALSO:A coating process comprises heating a layer of normally solid polyethylene or copolymer of ethylene and propylene containing up to 70 mol. per cent of the latter in contact with a vulcanizable composition of natural or synthetic rubber in the presence at the interface of a peroxide of the formula <FORM:0840208/III/1> wherein R1 is an aryl group, R6 is hydrogen, alkyl or aryl, and R2, R3, R4 and R5 are hydrogen or alkyl groups of less than four carbon atoms. The synthetic rubber may be a polymer of a conjugated diolefine or of chloroprene or a rubbery copolymer of a conjugated diolefine with another unsaturated compound, e.g. styrene, acrylonitrile or isobutylene.  The copolymer of ethylene and propylene may contain one or more additional unsaturated compounds copolymerizable therewith, e.g. butadiene, isoprene, dipentene or allo-ocimene in amount generally not exceeding 40% by weight.  The peroxide may be symmetrical or non-symmetrical, numerous examples are given, and may be incorporated in either layer or may be coated on the surface of one or both layers e.g. in solution in acetone.  A mixture of peroxides may be used.  The surface may be maintained under light pressure during the bonding.  The polyethylene or copolymer may be employed in the form of film, powder or flake, the two latter forms fusing during the heating step to form a coherent coating.  In Example 13, powdered high-density polyethylene is treated with an acetone solution of bis (a ,a -dimethyl benzyl) peroxide, dried and applied as a slurry in water containing the sodium salt of carboxymethyl cellulose to a slab of a synthetic rubber (GRS) mix containing the same peroxide. The coated slab was then heated in a mould.  Specifications 471,590, 721,046, 748,583, 748,632, 748,634, 753,349, 799,392, 799,823, 801,031, 804,641, 810,023, U.S.A. Specifications 2,658,059, 2,692,257, 2,692,258, 2,692,259, 2,692,295, 2,700,663, 2,702,288, 2,717,889, 2,728,755 and Belgian Specification 530,617 are referred to.