Abstract: A process for producing polymers of a conjugated diene, copolymers of a conjugated diene and another conjugated diene, or copolymers of conjugated diene and a vinyl aromatic hydrocarbon, which comprises polymerizing the corresponding monomers in the presence of a complex initiator consisting of components (a) and (b) described below, or (a) and (b) together with one or more components selected from components (c) and (d);(a) An organic compound of barium, strontium or calcium;(b) An organolithium-beryllium compound or an organolithiummagnesium compound;(c) An organolithium compound, an organoberyllium compound or an organomagnesium compound; and(d) An organoaluminum compound or an organozinc compound.The polymers of a conjugated diene containing relatively high trans-1,4 linkage, or the copolymers of a conjugated diene and a vinyl aromatic compound highly randomized and having high bound styrene and high trans-1,4 linkage can be produced at good yields.

Abstract: An isoprene-butadiene copolymer rubber having improved processing properties which comprises a microstructure of the butadiene portion having from 70% to 90% of trans-1,4 linkage and from 2% to 8% of vinyl linkage, an isoprene content of from 3 to 25 wt %, and a styrene content of from 0 to 30 wt %, said copolymer rubber having a Mooney Viscosity of from 30 to 150, and a molecular weight distribution, Mw/Mn of from 1.2 to 3.5, said rubber, in the unelongated state, not showing a melting point measured by the differential calorimeter analysis method. The copolymer rubber of the present invention can be used for tires, for example, a tread and a carcass or for other rubber uses.

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: An alkenyl aromatic resin composition having an excellent impact strength, which comprises (I) 100 parts by weight of a rubber-modified alkenyl aromatic resin containing from 2 to 35 wt. % of conjugated diolefin components, or a resinous mixture containing at least a component of the resin thereof; and (II) 1 to 50 parts by weight of a random segment copolymer containing at least a Segment A which is a random copolymer of a conjugated diolefin and a vinyl-substituted aromatic compound with a weight ratio being ranging from 30:70 to 5:95 and at least a Segment B, which is a conjugated diolefin polymer or a random copolymer of a conjugated diolefin and a vinyl-substituted aromatic compound with a weight ratio being ranging from 100:0 to 75:25, the random segment copolymer being characterized by containing;(a) at least 10 wt. % of Segment A based on the total random segment copolymer,(b) at least 20 wt. % of Segment B based on the total random segment copolymer, and(c) at least 60 wt.

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.

Abstract: The disclosure relates to a resin composition comprising (A) 75-98 parts by weight of a block copolymer mixture of vinyl aromatic hydrocarbon and conjugated diolefin and (B) 25-2 parts by weight of an impact-resistant styrene resin, characterized in that said copolymer mixture (A) is a mixture of a copolymer (1) and a copolymer (2) (the weight ratio of the copolymer (1) to the copolymer (2) is 1.

Abstract: High-impact polystyrene composition is produced by radical polymerization, e.g. bulk or bulk-suspension polymerization, of styrene having dissolved therein 2 to 20% by weight of one or more polybutadienes prepared by solution polymerization using an organic lithium compound as catalyst, said polybutadienes having (1) 1,2-vinyl content of more than 15 to 35% and cis-1,4 content of 20 to 85%, and (2) Mooney viscosity of 25 to 85, 5% styrene solution viscosity at 25.degree. C. being 50 to 200 cps and between 1.5 and 3.0 of the Mooney viscosity.

Abstract: Novel rubbery polymer having a uniform and broad molecular weight distribution, a ratio of weight average molecular weight to number average molecular weight of 3 or more, a content of monovinyl aromatic compound of 0 to 30% by weight, a bonding manner of conjugated diolefin of 60% or more of 1,4-linkage and improved processability and physical properties can be obtained by circulating living polymer in the polymerization or copolymerization of conjugated diolefins or copolymerization of conjugated diolefin and monovinyl aromatic hydrocarbon carried out with a lithium-based catalyst.