Patent GB-970379-A (GB)
Title: Improvements in or relating to adhesive bonding
IPC: A43B9/10
Filed: 1962-09-11
Abstract: Plasticized polyvinyl chloride is bonded to another material by applying to the p.v.c. surface, or to both surfaces, a solution of a linear polyurethane elastomer in a solvent capable of softening the p.v.c. surface, allowing the solvent to evaporate to leave a non-tacky film, heat-activating the film and pressing the materials together.  The p.v.c. used may be a copolymer of vinyl chloride and vinyl acetate, a mixture of such copolymer with p.v.c., or a mixture of any of the above with up to 10% of butadiene-acrylonitrile copolymer, polyvinylidene chloride, neoprene or isoprene.  The solvent may be tetrahydrofuran, dimethylformamide, mixtures thereof, or mixtures of such mixtures or of the separate solvents with up to 35% of methyl ethyl ketone. The p.v.c. may contain fillers, stabilizers, pigments and plasticizers such as di-2-ethyl-hexyl phthalate, tricresyl phosphate or epoxidized tall oil octyl ester. The polyurethane elastomer is a substantially linear polymer and is preferably obtained by reacting in the absence of moisture 1 mol. of a linear hydroxyl-terminated polyester of mol. weight 600-1,200 with about 1.1-3.1 mols. of diphenyl diisocyanate and 0.1-2.1 mols. of a free glycol of 4-10 C atoms; the polyester being obtained by esterifying an aliphatic dibasic acid containing an alkylene radical of 2-8 C atoms, e.g. adipic, succinic or pimelic acid, with a glycol of 4-10 C atoms e.g. butanediol-1, 4, in a glycol:  acid ratio of more than 1 mol:  1 mol.  The elastomer solution may contain fillers such as silica, clay and carbon black or synthetic resins such as p.v.c. In an example 1 mol. of hydroxyl-poly (tetramethylene adipate) of mol. weight 800 and hydroxyl number 140 and 1 mol. of butanediol-1, 4 are heated in an autoclave, 1.1 mol. of diphenyl methane p, p1 diisocyanate is added and the mixture reacted in a closed vessel at 140 DEG C.  The invention is especially applicable to the bonding of plasticized polyvinyl chloride outsoles to overlasted shoe uppers in which the p.v.c. may be of the compositions stated above, may contain carbon black, and may be moulded, e.g. injectionor slush-moulded, or cut from sheet.  The polyurethane solution is applied to the marginal parts of the outsole, allowed to dry, heat activated, and applied to overlasted parts of the uppers. The surface to be bonded may be preroughened.ALSO:Plasticized polyvinyl chloride, e.g. in the form of shoe outsoles, is bonded to another material such as a shoe upper, by applying to the pvc surface, or to both surfaces, a solution of a linear polyurethane elastomer in a solvent capable of softening the pvc surface, allowing the solvent to evaporate to leave a non-tacky film, heat-activating the film and pressing the materials together.  The pvc used may be a copolymer of vinyl chloride and vinyl acetate, a mixture of such copolymer with pvc, or a mixture of any of the above with up to 10% of butadiene-acrylonitrile copolymer, polyvinylidene chloride, neoprene or isoprene.  The solvent may be tetrahydrofuran, dimethylformamide, mixtures thereof, or mixtures of such mixtures or of the separate solvents with up to 35% of methyl ethyl ketone.  The pvc may contain fillers, stabilizers, pigments and plasticizers such as di-2-ethyl-hexyl phthalate, tricresyl phosphate, or epoxidized tall oil octyl ester.  The polyurethane elastomer is a substantially uncross-linked polymer and is preferably obtained by reacting in the absence of moisture 1 mol. of a linear hydroxyl-terminated polyester of mol. wgt. 600-1200 with about 1.1-3.1 mols. of diphenyl diisocyanate and 0.1-2.1 mols. of a free glycol of 4-10 C atoms; the polyester being obtained by esterifying an aliphatic dibasic acid containing an alkylene radical of 2-8 C atoms, e.g. adipic, succinic or pimelic acid, with a glycol of 4-10 C atoms e.g. butanediol-1,4, in a glycol:acid ratio of more than 1 mol:1 mol.  The elastomer solution may contain fillers such as silica, clay and carbon black or synthetic resins such as pvc.  In an example 1 mol. of hydroxyl-poly (tetramethylene adipate) of mol. wgt. 800 and hydroxyl number 140 and 1 mol. of butanediol-1,4 are heated in an autoclave, 1.1 mol. of diphenyl methane p, p1 diisocyanate is added and the mixture reacted in a closed vessel at 140 DEG C.  As applied to the bonding of plasticized polyvinyl chloride outsoles to overlasted shoe uppers the pvc, of the compositions stated above, may contain carbon black, and may be moulded, e.g. injection- or slush-moulded, or cut from sheet. The polyurethane solution is applied to the marginal parts of the outsole, allowed to dry, heat activated, and applied to overlasted parts of the uppers.  The surface to be bonded may be pre-roughened.