Abstract: A hydrogenated block copolymer or hydrogenated block copolymer mixture consisting essentially of (a) hydrogenation product of a star-branched block copolymer represented by the structural formula (A-B).sub.n X wherein A is a polybutadiene block having a 1,2-vinyl content of less than 25% by weight and B is a copolymer block containing 50% by weight or more of a conjugated diene compound whose vinyl content is 25% by weight or more, X is a coupling agent residue and n is an integer of 3 or more, and (b) a hydrogenation product of a straight chain block copolymer represented by the structural formula A-B wherein A and B are as defined above, the weight ratio of the component (a) to the component (b) being 100/0 to 5/95, and a hydrogenated block copolymer composition comprising (I) 1 to 99 parts by weight of said hydrogenated block copolymer or hydrogenated block copolymer mixture and (II) 99 to 1 part by weight of a thermoplastic resin and/or a rubbery polymer.

Abstract: A hydrogenated diene block copolymer having a polystyrene-reduced number-average molecular weight of 50,000-600,000 which is a hydrogenation product of an (A)-(B) block copolymer in which (A) means an alkenyl aromatic compound polymer block and (B) means a conjugated diene homopolymer block wherein the vinyl content of the conjugated diene portion is more than 60%, or an alkenyl aromatic compound-conjugated diene random copolymer block wherein the vinyl content of the conjugated diene portion is 15% or more, an (A)-(B)-(C) block copolymer in which (A) and (B) are as defined above and (C) means an alkenyl aromatic compound-conjugated diene copolymer tapered block wherein the proportion of the alkenyl aromatic compound increases gradually, or an (A)-(B)-(A) block copolymer in which (A) and (B) are as defined above. Said hydrogenated diene block copolymer is useful as a modifier for polar resins, non-polar resins or both of them.

Abstract: A hydrogenated diene block copolymer having a polystyrene-reduced number-average molecular weight of 50,000-600,000 which is a hydrogenation product of an (A)-(B) block copolymer in which (A) means an alkenyl aromatic compound polymer block and (B) means a conjugated diene homopolymer block wherein the vinyl content of the conjugated diene portion is more than 60%, or an alkenyl aromatic compound-conjugated diene random copolymer block wherein the vinyl content of the conjugated diene portion is 15% or more, an (A)-(B)-(C) block copolymer in which (A) and (B) are as defined above and (C) means an alkenyl aromatic compound-conjugated diene copolymer tapered block wherein the proportion of the alkenyl aromatic compound increases gradually, or an (A)-(B)-(A) block copolymer in which (A) and (B) are as defined above and in which hydrogenation product at least 80% of the double bonds of the conjugated diene portion is saturated by the hydrogenation.

Abstract: A hydrogenated diene block copolymer having a polystyrene-reduced number-average molecular weight of 50,000-600,000 which is a hydrogenation product of an (A)--(B) block copolymer in which (A) means an alkenyl aromatic compound polymer block and (B) means a conjugated diene homopolymer block wherein the vinyl content of the conjugated diene portion is more than 60%, or an alkenyl aromatic compound-conjugated diene random copolymer block wherein the vinyl content of the conjugated diene portion is 15% or more, an (A)--(B)--(C) block copolymer in which (A) and (B) are as defined above and (C) means an alkenyl aromatic compound-conjugated diene copolymer tapered block wherein the proportion of the alkenyl aromatic compound increases gradually, or an (A)--(B)--(A) block copolymer in which (A) and (B) are as defined above, in which block copolymer(1) the weight proportion of theh alkenyl aromatic compound/the conjugated diene is 5/95 to 60/40, and(2) the content of the bound alkenyl aromatic compound in at least o

Abstract: A hydrogenation catalyst composition comprising, as essential components, (a) at least one bis(cyclopentadienyl)transition metal compound represented by general formula (i): ##STR1## and (b) at least one member selected from the group consisting of complex compounds represented by general formulas (ii) and (iii): ##STR2## and further comprising, if necessary, (c) at least one polar compound selected from the group consisting of ether compounds, thioether compounds, ketone compounds, sulfoxide compounds, carboxylic acid ester compounds, lactone compounds, amine compounds, amide compounds, nitrile compounds and oxime compounds and/or (d) an alkali compound represented by general formula (iv):M.sup.2 OR.sup.7 (iv)The contact of an olefinically unsaturated polymer with hydrogen in the presence of said catalyst composition enables the selective hydrogenation of the olefinic double bonds in said polymer.

Abstract: A hydrogenated diene copolymer resin composition comprising (A) 5-70% by weight of a hydrogenated diene copolymer which is a hydrogenation product of a random copolymer of at least one conjugated diene and 3-50% by weight of an alkenyl aromatic compound having a number average molecular weight of 5,000-1,000,000 and a molecular weight distribution (Mw/Mn) of 10 or less, the vinyl content in the diene portion of the random copolymer being 10-90%, at least 70% of the olefinic unsaturation of the random copolymer being hydrogenated, and (B) 95-30% by weight of at least one resin selected from the group consisting of a polypropylene resin, a polyphenylene ether resin and an alkenyl aromatic compound polymer resin.

Abstract: A hydrogenation catalyst consisting essentially of (A) at least one bis(cyclopentadienyl)titanium compound represented by the formula (1): ##STR1## wherein R.sup.1 and R.sup.2, which may be the same or different, represent halogen atoms, hydrocarbon groups, aryloxy groups, alkoxy groups or carbonyl groups, and (B) at least one lithium compound represented by the formula (2):R.sup.3 O--Li (2)wherein R.sup.3 represents a hydrocarbon group, or a reaction mixture of an organolithium compound with an alcoholic or phenolic hydroxyl group-containing compound, the (A) component/the (B) component molar ratio being 1/0.5 to 1/20, and optionally (C) at least one reducing organometallic compound selected from the group consisting of aluminum compounds, zinc compounds and magnesium compounds, the (A) component/the (C) component molar ratio being 1/0.5 to 1/20.