Patent GB-984293-A (GB)
Title: Polyurethane adhesive
IPC: C08G18/66
Filed: 1962-03-09
Abstract: A polyurethane polymer is bonded to metal by priming the metal with an adhesive comprising a polyepoxy adhesive having a viscosity at 25 DEG  C. of at least 0.5 poises, compounded with addition polymers of olefins containing 2 to 10 carbon atoms which mixture is applied as a solution or dispersion in a volatile carrier, the polyurethane then being cast on to the primed metal. The epoxide may be the reaction product of epichlorhydrin with ethylene glycol, glycerol, pentaerythritol, butenediol, butanediol, trimethylol propane, resorcinol, "bisphenol A," phoroglucinol, catechol, or hydroquinone, or 1,3 - bis - [3 - (2,3 - epoxy propoxy)propyl] tetramethyl silicone, the bis-epoxydicyclopentyl ether of ethylene glycol, or an epoxylated phenol-formaldehyde novolac.  The addition polymer may be a butadiene-styrene, butadiene, acrylonitrile, isoprene-styrene, isoprene-acrylonitrile or chloroprene polymer. The metal surface which may be iron, steel, stainless steel, aluminium, zinc or brass may first be cleaned chemically, degreased and/or shotblasted or sand-blasted; the adhesive is then applied as a solution or dispersion in toluene, ethylene dichloride, methyl ethyl ketone, monochlorobenzene or methylene dichloride by dipping, spraying or brushing.  The polyurethane reaction mixture is then cast against the coated surface; this mixture comprises (1) a reactive hydrogen containing material of molecular weight 700-10,000; (2) an organic polyisocyanate; and (3) a diamine. Preferably (1) is a polyester of molecular weight 1500 to 2500, hydroxyl number 45 to 75 and acid number not greater than 5; (2) is 3,31-dimethyl -4,41-diphenylene diisocyanate; and (3) is orthodichlorobenzidine, but (1) may be other polyesters, e.g. those prepared from succinic, glutaric, adipic, pimelic, suberic, azelaic or sebacic acids with ethylene, propylene, butylene, pentamethylene or hexamethylene glycol or a mixture thereof; (2) may be butylene 1,4-diisocyanate, phenylene diisocyanates, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 3,31 - dimethoxy - 4,41 - biphenylene diisocyanate, 3,31 - diphenyl - 4,41 - diphenylene diisocyanate, 3,31 - dichloro - 4,41 - biphenylene diisocyanate, naphthalene diisocyanate, or triphenyl methane triisocyanate; and (3) may be tolyelene diamine, nitrobenzidine, 4-amino21-aminodiphenyl, dianisidine, methylene bischloroaniline, diaminophenetole, 4,41-diaminodiphenylmethane, 3,31 - dichloro - 4,41 - diaminodiphenylmethane, 1,5 - naphthylene diamine, phenylene diamine, 2,5-dichlorophenylene diamine, piperazine, 1,4-diaminobutane or hexylene diamine.  The reaction mixture may be cured by heating after casting.ALSO:A polyurethane polymer is bonded to metal by priming the metal with an adhesive comprising a polyepoxy adhesive having a viscosity at 25 DEG C. of at least 0,5 poises, compounded with addition polymers of olefins containing 2-10 carbon atoms, which mixture is applied as a solution or dispersion in a volatile carrier, the polyurethane then being cast on to the primed metal. The epoxide may be the reaction product of epichlorhydrin with ethylene glycol, glycerol, pentaerythritol, butenediol, trimethylol propane, resorcinol, "bis-phenol A", phloroglucinol, catechol, or hydroquinone, or 1,3-bis[3(2,3-epoxy propoxy)propyl] tetramethyl silicone, the bis-epoxydicyclopentyl ether of ethylene glycol, or an epoxylated phenolformaldehyde novolac.  The addition polymer may be a butadiene-styrene, butadiene-acrylonitrile, isoprene-styrene, isoprene-acrylonitrile or chloroprene polymer.  The metal surface, which may be iron, steel, stainless steel, aluminium, zinc or brass, may first be cleaned chemically, degreased and/or shot-blasted or sand-blasted; the adhesive is then applied as a solution or dispersion in toluene, ethylene dichloride, methyl ethyl ketone, monochlorobenzene or methylene dichloride by dipping, spraying or brushing.  The polyurethane reaction mixture is then cast against the coated surface; this mixture comprises (1) a reactive hydrogen-containing material of molecular weight 700-10,000; (2) an organic polyisocyanate; and (3) a diamine.  The reaction mixture may be cured by heating after casting.