Toyo Boseki Kabushiki Kaisha

Kureha Kagaku Kogyo Kabushiki Kaisha

Chikara Sugitawa

Mitsuru Hoshino

Takeshi Yatsuka

Haruhiko Yusa

Shigeo Kobayashi

Hironobu Furusawa

Hironobu Kitagawa

Takuma Kobayashi

Misao Sumoto

Hiroshi Imanaka

Hirotoshi Kizumoto

Osamu Imagawa

Kuniyuki Doi

Futoshi Ishimaru

Yoshihiko Kijima

Satoshi Nakamura

Akira Kurosaki

A magnetic recording medium possessing a magnetic layer formed by application onto a non-magnetic support, of a magnetic coating containing magnetic particles dispersed in a binder which contains a polyurethane resin, together with carbon black particles at 5% by weight or higher, based on the weight of the magnetic particles. The polyurethane resin to be used herein is composed of: (a) a polyester polyol having a molecular weight of 2000 or lower and containing at least one selected from the group consisting of aromatic dibasic acids and alicyclic dibasic acids at a ratio of 90 mol % or higher of acid components; (b) a high molecular weight polyol having a molecular weight of 5000 or lower, which is at least one selected from the group consisting of (b1) polyester polyols each containing an aliphatic dibasic acid at a ratio of 90 mol % or higher of acid components, (b2) polylactones, (b3) polyester polyols, and (b4) polycarbonate polyols; (c) an organic diisocyanate compound; and (d) an optional compound having a molecular weight of 500 or lower and containing at least two functional groups in one molecule, which are reactive with isocyanate groups.

Magnetic recording media and thermoplastic polyurethane resins therefor

A thermoplastic polyurethane composition of the present invention includes a thermoplastic polyurethane obtained by reacting at least the following components A, B, and C: (A) a polyester polyol having a number average age molecular weight of 500 to 5000, containing an acid component including aromatic dicarboxylic acid and aliphatic dicarboxylic acid, the molar ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid being 5:95 to 90:10; (B) a low molecular weight diol having a molecular weight of less than 500; and (C) an organic diisocyanate, wherein the thermoplastic polyurethane has a metal sulfonate group of 10 to 1000 equivalents/10.sup.6 g of the polyurethane and a urethane group of 1200 to 3000 equivalents/10.sup.6 g of the polyurethane.

Thermoplastic polyurethane

An improved polyester block copolymer composition having a rubber-like elasticity, particularly having excellent moldability, impact resistance, heat resistance and water resistance, which comprises a polyester block copolymer produced from a crystalline aromatic polyester and a lactone in melt-admixture with a polytetramethylene terephthalate and optionally further with at least one epoxy compound.

Polyester block copolymer composition

Disclosed herein is a composition of a polyester-block copolymer, comprising 5 to 80% by weight of at least one kind of graft-copolymer obtained by graft-copolymerizing 50 to 25 parts by weight of a monomeric mixture predominantly consisting essentially of styrene and methyl methacrylate and containing 0.01 to 3.0% by weight of a cross-linking agent with 50 to 75 parts by weight of a cross-linked elastomeric trunk polymer containing not less than 50% by weight of rubber like segment selected from the group consisting of butadiene unit and C.sub.4 to C.sub.10 -alkyl acrylate units, and 0.01 to 3.0% by weight of a cross-linking agent, and 95 to 20% by weight of a polyester-block copolymer, the composition giving shaped articles of favorable superficial appearance even when processed by shape-forming under conditions of mixing and kneading of a relatively low degree.

Composition of polyester-block copolymer

A composition comprising an intimate mixture of a segmented thermoplastic polyester copolymer and at least one polyolefin. This composition is improved in recovery from creep at high temperature as well as in ease of hot cutting and adhesion.

Polyester copolymer compositions

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Otsu, Japan

Chikara Sugitawa