Abstract: A block copolymer containing two or more polymer blocks composed mainly of an aromatic vinyl hydrocarbon and one or more polymer blocks composed mainly of a conjugated diene having excellent mechanical properties can be advantageously prepared by (a) batchwise preparing the specified living polymer (i.e. prepolymer) of at least one aromatic vinyl hydrocarbon polymer block by using a portion of monomers, and, then, (b) continuously preparing the block copolymer for continuously polymerizing the remainder of the monomers by continuously supplying the prepolymer to the first polymerization vessel of a continuous polymerization zone and simultaneously supplying the remainder of the monomers in the form of a monomer composed mainly of the aromatic vinyl hydrocarbon and/or a monomer composed mainly of the conjugated diene continuously and separately to the subsequent polymerization vessel(s).

Abstract: A block copolymer containing two or more polymer blocks composed mainly of an aromatic vinyl hydrocarbon and one or more polymer blocks composed mainly of a conjugated diene having excellent mechanical properties can be advantageously prepared by (a) batchwise preparing the specified living polymer (i.e. prepolymer) of at least one aromatic vinyl hydrocarbon polymer block by using a portion of monomers, and, then, (b) continuously preparing the block copolymer for continuously polymerizing the remainder of the monomers by continuously supplying the prepolymer to the first polymerization vessel of a continuous polymerization zone and simultaneously supplying the remainder of the monomers in the form of a monomer composed mainly of the aromatic vinyl hydrocarbon and/or a monomer composed mainly of the conjugated diene continuously and separately to the subsequent polymerization vessel(s).

Abstract: A thermoplastic polymer composition containing (i) a modified block copolymer of an aromatic vinyl compound and a conjugated diene compound, which is modified with a dicarboxylic acid or the derivative thereof, or the ionically crosslinked product of the modified block copolymer with a univalent, bivalent of trivalent metal ion and (ii) a thermoplastic polymer having a polar group. This thermoplastic polymer composition has excellent mechanical and other properties. The compatibility of each component in the thermoplastic composition is remarkably improved.

Abstract: In producing a block copolymer resin having vinyl aromatic hydrocarbon polymer blocks such as of styrene and polymer blocks primarily composed of conjugated diene such as of butadiene successively through living polymers using an organolithium compound as a catalyst in an aliphatic solvent, the vinyl aromatic hydrocarbon monomer for forming the vinyl aromatic hydrocarbon polymer block is added at a controlled rate, at the stage when the vinyl aromatic hydrocarbon content in the polymer formed has reached a certain value, higher than the polymerization rate of the vinyl aromatic hydrocarbon monomer at the polymerization temperature but at a rate which can maintain the solubility parameter of the liquid phase portion in the polymerization system at 7.7 or less, whereby a block copolymer resin with good transparency and impact strength can be produced with good productivity.

Abstract: A hot-melt pressure-sensitive adhesive composition comprising (a) 100 parts by weight of a specific grafted block copolymer material formed by the graft reaction of at least one block copolymer comprising at least one polybutadiene or polyisoprene block and at least two polystyrene blocks with at least one unsaturated carboxylic acid monomer and/or derivative monomer thereof and (b) 50 to 250 parts by weight of a specific tackifier mixture consisting of a tackifier S comprising at least 50% by weight of a terpene resin having a softening point of 60.degree. C. or more and a tackifier L comprising at least 50% by weight of a terpene resin having a softening point of 30.degree. C. or less and having an S/L mixing weight ratio of 9/1 to 3/7, and optionally 1 to 50 parts by weight of a softening agent has been found to be excellent in holding power especially for paper.

Abstract: A multi-layer laminate comprising at least one A-B double layer structure, characterized in that said layer A is a layer comprising at least one material selected from the group consisting of olefin polymers, polyamide polymers, acrylate polymers, polyether polymers, polycarbonate polymers, polyurethane polymers, vinylidene chloride polymers, thermosetting resins, vulcanized rubbers, glass and papers and said layer B is a layer comprising mainly a modified block copolymer in which an unsaturated carboxylic acid or its derivative is grafted on a styrene-butadiene block copolymer. Said laminate is excellent in interlaminar adhesion, i.e. peeling strength.

Abstract: A thermosetting unsaturated polyester resin composition comprising (a) an unsaturated polyester, (b) a modified block copolymer comprising a block copolymer of vinyl aromatic compound and conjugated diene compound onto which an unsaturated dicarboxylic acid and/or an unsaturated dicarboxylic acid derivative is grafted, (c) a vinyl monomer, (d) a curing agent and, if necessary, (e) other additives, the amounts of said (a), (b) and (c) constituents being 10 to 90 parts by weight, 2 to 70 parts by weight, and 10 to 80 parts by weight, respectively, the total amount of (a), (b) and (c) being 100 parts by weight, and the proportion of (d) being 0.1 to 10 parts by weight per 100 parts by weight of the total amount of (a), (b) and (c). The above composition is excellent in impact resistance, surface characteristics and rigidity.

Abstract: A thermoplastic styrene polymer composition having excellent mechanical and processing properties is presented. This composition contains:(A) 1 through 99% by weight of a component A consisting essentially of at least one styrene polymer selected from the group consisting of polystyrene and styrene-containing polymers having a weight-average molecular weight of 50,000 through 500,000; and(B) 99 through 1% by weight of a component B consisting essentially of at least one ionically crosslinked product of at least one modified block copolymer with at least one univalent, bivalent or trivalent metal ion, said modified block copolymer comprising a block copolymer of at least one aromatic vinyl compound and at least one conjugated diene compound onto which at least one molecular unit containing at least one dicarboxylic acid group or the derivative thereof is grafted.

Abstract: A process for preparing a modified block copolymer by graft-reacting at least one maleic acid compound with an aromatic vinyl compound/conjugated diene compound block copolymer containing at least one polymer block mainly composed of a conjugated diene compound and at least one polymer block mainly composed of an aromatic vinyl compound, the aromatic vinyl compound/conjugated diene compound weight ratio being within the range of 5/95 to 97/3, characterized in that said graft-reaction is carried out under conditions wherein the generation of radicals can be substantially inhibited. According to this process, it is possible to prevent gelation of the product in the graft-reaction, and the modified block copolymer obtained has excellent appearance characteristics, mechanical properties, and transparency.