Asahi Kasei Kabushiki Kaisha

Asahi Kasei Chemicals Corporation

Yukio Yamaura

Susumu Hoshi

Junko Kakegawa

Toshinori Shiraki

Junichi Yoshida

Masahiro Mori

Kenta Hisamura

Chigusa Yamada

Tsutomu Sugimoto

The present invention provides a modified conjugated diene-based polymer, wherein the Mooney stress-relaxation rate measured at 110&#xb0; C. is 0.45 or less, and the modification percentage is 75% by mass or more.

Modified conjugated diene-based polymer and method for producing the same, and modified conjugated diene-based polymer composition

An object of the invention is to provide a block copolymer hydrogenation product suitable for a sheet and a heat shrinkable film which are excellent in solvent resistance, rigidity, elongation and transparency, which is excellent in a balance of physical properties such as solvent resistance, natural shrinkability, low-temperature shrinkability, rigidity, transparency and low-temperature elongation, and a composition thereof. The invention relates to a block copolymer hydrogenation product having a weight ratio of a vinyl aromatic hydrocarbon and a conjugated diene of 55/45 to 95/5, a number average molecular weight measured by gel permeation chromatography (GPC) of 30,000 to 500,000 and a hydrogenation rate of 30% or more, wherein the vinyl aromatic hydrocarbon incorporated into the hydrogenation product has a block rate of 60 to 98% by weight, wherein relative to the weight of the total vinyl aromatic hydrocarbon polymer blocks, the ratio of vinyl aromatic hydrocarbon polymer blocks having a molecular weight of 50,000 or less is 80% by weight or more and the ratio of vinyl aromatic hydrocarbon polymer blocks having a molecular weight of 15,000 or less is from 10 to 80% by weight, and wherein at least one peak temperature of function tan &#x3b4; in a dynamic viscoelasticity measurement of the hydrogenation product is present within the range of exceeding &#x2212;80&#xb0; C. to lower than &#x2212;10&#xb0; C.

Hydrogenation product of block copolymer or sheet or film of the same

The present invention provides a block copolymer or a hydrogenated product thereof excellent in low-temperature shrinkability, natural shrinkability, rigidity and the like, excellent in a balance of physical properties such as blocking resistance, resistance to fusion bonding in hot water, impact resistance and the like, and having a few fish eyes (FE's) caused by gels. Further, the invention provides a heat shrinkable film and a heat shrinkable multilayer film suitable for drink container packaging, cap seals and the like, using such a block copolymer or the hydrogenated product thereof. The invention provides a block copolymer having a weight ratio of a vinyl aromatic hydrocarbon and a conjugated diene of 60/40 to 90/10 and a number average molecular weight measured by gel permeation chromatography (GPC) of 30,000 to 500,000, wherein the vinyl aromatic hydrocarbon constituting the block copolymer has a block rate of from 10 to 90% by weight, the vinyl aromatic hydrocarbon polymer blocks constituting the block copolymer have a peak molecular weight within the molecular weight range of 5,000 to 30,000, and 40 to 80% by weight of the vinyl aromatic hydrocarbon polymer blocks have a molecular weight of 35,000 or less.

Block copolymer and composition thereof

Disclosed is a block copolymer composition comprising a block copolymer (I) comprising at least two polymer blocks (each polymer block (S) comprising vinyl aromatic hydrocarbon monomer units) and at least one polymer block (B) comprising isoprene monomer units and 1,3-butadiene monomer units, and a polystyrene resin (II), wherein, in the block copolymer (I), the amount of the vinyl aromatic hydrocarbon monomer units, the total amount of the isoprene monomer units and the 1,3-butadiene monomer units, and the isoprene monomer unit/1,3-butadiene monomer unit weight ratio are within specific range, wherein the block copolymer (I) has a vinyl aromatic hydrocarbon block ratio (BL) within a specific range, and wherein the block copolymer (I) and the polystyrene resin (II) satisfy a relationship represented by the following formula (1):15+0.25&#x2266;35+0.25&#x2003;&#x2003;(1)wherein BL represents the block ratio of the copolymer (I), and Wa represents the weight percentage, based on the total weight of the copolymer (I) and the resin (II), of the copolymer (I).

Block copolymer composition

Disclosed is a block copolymer comprising at least two S polymer blocks comprising vinyl aromatic hydrocarbon monomer units, and one B polymer block or two or more B polymer blocks which contains or collectively contain isoprene monomer units and 1,3-butadiene monomer units, wherein the amount of the vinyl aromatic hydrocarbon monomer units and the total amount of the isoprene monomer units and the 1,3-butadiene monomer units are, respectively, from 60 to 95% by weight and from 40 to 5% by weight, each based on the weight of the copolymer, wherein the isoprene monomer unit/1,3-butadiene monomer unit weight ratio is from 45/55 to 97/3, and wherein the vinyl aromatic hydrocarbon monomer unit moiety of the copolymer has a short segment ratio of from 0 to 30% by weight, which is defined as the weight percentage, based on the total weight of vinyl aromatic hydrocarbon monomer units in the copolymer, of the vinyl aromatic hydrocarbon monomer units in at least one short segment consisting of 1 to 3 vinyl aromatic hydrocarbon monomer units.

Disclosed is a linear block copolymer comprising at least two vinyl aromatic hydrocarbon polymer blocks (S), at least two conjugated diene polymer blocks (B) and at least one vinyl aromatic hydrocarbon/conjugated diene copolymer block (B/S); the linear block copolymer having a specific block configuration wherein both terminal polymer blocks of the linear block copolymer are S blocks, both terminal S blocks have, bonded directly to the respective inner ends thereof, B blocks, and the B blocks, which are bonded directly to the respective inner ends of both terminal polymer blocks (S), have therebetween one or two B/S blocks which is or are bonded directly to the respective inner ends of the polymer blocks (B); the linear block copolymer comprising at least two fractions having different peak molecular weights, and both terminal S blocks in total comprising at least two fractions having different peak molecular weights. Also disclosed is a resin composition comprising the linear block copolymer and a styrene-containing resin in a specific amount ratio.

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Tokyo, Japan

Yukio Yamaura