Adhesive composition

Claim 1

An adhesive composition prepared by mixing in the presence of a volatile organic solvent selected from at least one of the group consisting of toluene, benzene, pentane, hexane, heptane and octane, as well as unreacted hydrocarbons, (1) about 100 parts by weight of a rubber primarily selected from at least one of a natural rubber and synthetic rubber selected from cis-1,4-polyisoprene, cis-1,4-polybutadiene, butyl rubber, ethylene/propylene/non-conjugated diene rubber, aqueous emulsion copolymerized 1,3-butadiene and styrene, and an unvulcanized elastomeric block copolymer having the general configuration A - B - A wherein each A is an independently selected nonelastomeric styrene polymer block having an average molecular weight of about 2,000 to about 100,000 and a glass transition temperature above about 25° C., the total block A content being from about 10 to about 50 percent by weight of the copolymer, and B is an elastomeric conjugated diene polymer block of a diene selected from 1,3-butadiene and isoprene having an average molecular weight from about 25,000 to about 1,000,000 and a glass transition temperature below about 10° C., said copolymer having a tensile strength at 25° C., in excess of about 200 pounds per square inch, and (2) about 60 to about 140 parts by weight of a compatible, thermoplastic tackifying resin containing carbon-to-carbon unsaturation therein and having a softening point in the range of about 60° C. to about 80° C. and drying the resulting composition, said tackifying resin being prepared by the method which comprises (A) reacting in the presence of an aliphatic hydrocarbon solvent and a catalyst selected from aluminum chloride and ethyl aluminum dichloride, a monomer mixture consisting of 60 to about 75 weight percent of a diolefin/olefin mixture of a weight ratio in the range of about 0.6/1 to about 1.4/1 and, correspondingly, about 40 to about 25 weight percent α-methyl styrene, where said diolefin consists of at least about 95 weight percent piperylene and up to about 5 weight percent isoprene based of the diolefin, and where said olefin comprises at least one olefin selected from 2-methyl-2-butene, 2-methyl-2-pentene and 2-methyl-1-pentene and (B) recovering the resin from the polymerization mixture by first neutralizing the catalyst with a material selected from water, lime and at least one alcohol selected from methanol, isopropanol and butanol, followed by stream stripping the filtrate thereof to remove volatiles.