Patent GB-1441278-A (GB)
Title: Pressure sensitive adhesive product and method of making the same
IPC: C09J7/38
Filed: 1973-07-02
Abstract: 1441278 Pressure sensitive adhesives D O KEST 2 July 1973 31341/73 Heading C3P Pressure sensitive adhesives, especially for use in laminated products, comprise (I) an elastomeric material which is formed in situ in the presence of component (II) by the reaction of (a) a liquid diene or acrylate telechelic polymer material having an average of at least 1À6 essentially terminal reactive functional groups per molecule, said groups being attached to one of the last three carbon atoms at an end of the polymer molecule, and (b) an organic co-reactant having on average more than one co-reactive functional, the ratio of co-reactive groups to reactive groups being in the range from 0À75 : 1 to 1À2 : 1, component (II) being a tackifying resin present in an amount of at least 75 parts by weight per 100 parts of elastomer material. Components (a) and (b) may be partially reacted to form a prepolymer before the adhesive formation. Component (b) is usually polyfunctional, but some monofunctional reactant may additionally be present. Numerous other adhesive components may be present, e.g. reactive polyethers and/or polyesters, chainextending and/or cross-linking compounds, a diene elastomer, plasticizers, oils, solvents, catalysts, acid inhibiters &c. The adhesives are usually formulated in two parts, one of which contains interalia the telechelic polymer and the tackifying resin, and the other contains inter alia the organic co-reactant. In examples, the adhesives contain components selected from the following: telechelic polymers: hydroxyterminated polybutadiene or butadiene/acrylonitrile or butadiene/styrene copolymers, carboxy-terminated butadiene/acrylonitrile copolymer, thiol-terminated butadiene/acrylonitrile copolymer, allylic bromide-terminated polybutadiene and mercaptan-terminated poly- (butyl aerylate); organic co-reactants: a mixed organic polyisocyanate, a mixture of p,p<SP>1</SP>- methylene diphenyl diisocyanate and polymethylene polyphenyl isocyanate, 4,4<SP>1</SP>-methylene-bis-(cyclohexyl isocyanate), methylated triethylene tetramine, and the diglycidyl ether of Bisphenol A; tackifying resins: polyterpene phenolic resin, alpha-pinene resin, hydroabietyl phthalate and the pentaerythritol ester of saturated abietic acid; monofucntional reactant: octadecyl isocyanate; reactive polyether: glycerine/propylene oxide condensate; chain-extender/cross-linker: N,N - bis - (2 - hydroxypropyl)aniline: diene elastomers: styrene/isoprene/styrene block copolymer: plasticizers: liquid poly-(vinyl ethyl ether) high M.W. commercial polymeric plasticizer, butyl benzyl phthalate and chlorinated biphenyl; solvents: toluene, heptane and methyl ethyl ketone; catalysts: dibutyl tin diacetate or dilaurate; oils: a paraffinic mineral oil; other additives: water, octyl-2,2-diphenyl-1-cyanoacrylate and phenolic antioxidants. The adhesive-precursor compositions are cast on to silicone-treated release paper and heated to initiate in situ formation of the pressuresensitive adhesives. After cooling the adhesivecoated paper is then laminated to a plastic substrate web, e.g. of polypropylene film or biaxially oriented polyethylene terephthalate, and the laminate conditioned for at least 48 hours at ambient temperature. The release paper is then removed and the pressure sensitive adhesive tested for adhesion to stainless steel test panels. In one example plasticized PVC is mentioned as a substrate for the adhesive.