Kuraray Co., Ltd.

Shobu Minatono

Hideo Takamatsu

Junnosuke Yamauchi

Masao Ishii

Katsuyoshi Terao

Kazushige Ishiura

Yoshiki Nobuto

Takayuki Okamura

Makoto Nishikawa

Toshimitu Kawame

Atsushi Ooishi

Miduho Maeda

The present invention provides an alkaline water-soluble thermoplastic resin comprising units from isobutylene, units from maleic anhydride and units from n-butyl acrylate unit in a molar ratio of isobutylene units, maleic anhydride units and n-butyl acrylate units of 1:0.8-1.2:0.2-5.0.

Alkaline water-soluble thermoplastic resin and adhesive comprising the

A process for the hydrogenation of conjugated diene polymers having alcoholic hydroxyl groups, is provided. In the process, reduced nickel is used as a catalyst and an ether or a mixture of an ether and a hydrocarbon is used as a solvent for the hydrogenation reaction whereby elimination of the group rarely occurs with a very high hydrogenation rate being attained.

Process for the hydrogenation of conjugated diene polymers having

A block copolymer having a numerical average molecular weight of 30,000 to 300,000 composed of two or more blocks consisting of aromatic vinyl units having a numerical average molecular weight of 2500 to 40,000, and one or more blocks containing a vinyl bonding content of not less than 40%, having a peak temperature of primary dispersion of tan .delta. at least 0.degree. C., and consisting of isoprene or isoprene-butadiene units in which at least a part of carbon-carbon double bonds may be hydrogenated, and a composition consisting of the block copolymer. The composition can provide a vibration-damping material.

Block copolymers and composition containing the same

A pressure sensitive adhesive composition is provided which comprises a tri-block copolymer (a) consisting of aromatic vinyl block-conjugated diene block-aromatic vinyl block in which the conjugated diene moiety is hydrogenated and a block copolymer (b) consisting of an aromatic vinyl block and a conjugated diene block in which the conjugated diene moiety is hydrogenated. The adhesive composition is significantly improved in low temperatures characteristics, adhesion and processability with good adhesion.

Pressure sensitive adhesive composition

Modified cis-1,4-polyisoprene rubber obtained by incorporating into cis-1,4-polyisoprene rubber a side chain formed by succinimide residue containing in the N position a hydrocarbon residue having at least one tertiary nitrogen atom. This rubber is excellent in green strength at ordinary room temperature, and flowability at an elevated temperature. Its vulcanizate is comparable to, or better than natural rubber in breaking strength and hardness.

Modified cis-1,4-polyisoprene rubber, a process for manufacturing the

There is provided a curable sealing composition comprising a low molecular weight rubber, a curing agent and other additives as required and being characterized in that a block copolymer of isoprene and butadiene with a viscosity average molecular weight of 7,000-150,000 is used as the low molecular weight rubber. The composition has a good workability, and when cured, produces seals having excellent thermal stability, elasticity and sealing effect.

Curable sealing composition

A hydrous gel consisting essentially of a water-in-oil dispersion cured with a crosslinking agent. The dispersion comprises a rubber component in which water is dispersed in the form of droplets in the presence of a surfactant. The rubber component is based on a liquid polyisoprene rubber having a cis-1,4 content of not less than 70% and a molecular weight of 8,000 to 120,000 or a modified polyisoprene rubber which is an adduct of the above-mentioned liquid polyisoprene rubber and maleic anhydride or a derivative thereof. The hydrous gel provides cold- and heat-retaining materials, perfume-retaining materials, adhesives for medical use, poultices and shock-absorbing materials.

Hydrous gel

A rubber composition with improved processability and capable of affording a vulcanizate with improved properties including improved adhesion to a metal surface is disclosed. The composition comprises a modified liquid polyisoprene rubber and a natural rubber. The modified liquid polyisoprene rubber is an adduct of maleic anhydride or a derivative thereof with a liquid polyisoprene rubber with a cis-1,4 content of not less than 70% and a molecular weight of 8,000 to 100,000, the amount of said maleic anhydride or said derivative being 0.1 to 15 mol % per isoprene unit in said liquid polyisoprene rubber.

Rubber composition

A pressure-sensitive adhesive composition based on liquid rubber, a cross-linking agent therefor and a tackifier, in which the liquid rubber component is a modified low molecular weight polyisoprene which is obtainable by adding 0.03 to 7 mol % of maleic anhydride or a derivative thereof, based on each isoprene monomer unit, to a low molecular weight polyisoprene having a molecular weight in the range of 10,000 to 90,000 is useful in producing a pressure-sensitive adhesive composition having very desirable tackiness, cohesive force and bonding characteristics without use of an organic solvent or with use of only a small amount of the solvent.

A pressure-sensitive adhesive composition having excellent tackiness and improved thermal resistance comprises (A) a low molecular weight polyisoprene, which may be obtained by polymerizing isoprene monomer with the aid of a lithium-type catalyst, said polyisoprene having a cis-1,4 content of not less than 75%, a viscosity average molecular weight of 8,000 to 77,000 and an Mw/Mn value (Mw: weight average molecular weight; Mn: number average molecular weight) of 1.0 to 2.7 and (B) an elastomer.

Pressure sensitive adhesive compositions

A modified cis-1,4-polyisoprene rubber having enhanced green strength is produced by reacting said rubber with maleic anhydride in a solvent including an aliphatic hydrocarbon or an alicyclic hydrocarbon or an alicyclic hydrocarbon; the efficiency of the reaction of the maleic anhydride is markedly increased by employing a relatively minor amount of an aromatic hydrocarbon in combination with the aliphatic or alicyclic hydrocarbon reaction solvent.

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Kashima, Japan

Shobu Minatono