Sumitomo Chemical Company, Limited

Masahiro Niwano

Kenji Manabe

Takenobu Kanazawa

Jiro Horikawa

Masahiko Moritani

Kazunori Akiyoshi

Takeo Saegusa

Makoto Namioka

Nobuko Nakayama

Saegusa Takeo

Kuniaki Asai

Shuji Kitamura

Yoshiharu Tatsukami

Ichiki Murase

Tadashi Hikasa

Fumio Fujita

Katsuhiko Iwasaki

Yoshitaka Ohbe

Yushin Kataoka

Shozaburo Imai

Toshifumi Tamura

Kazuhiro Yokoo

Michihisa Isobe

Itaru Nitta

Takanori Fujita

Shojiro Itoh

Masato Ogura

Yukinori Dairaku

Masaru Oota

Toshihiro Oonishi

A process for producing an aromatic polyamide film comprising forming a thin layer of an optically isotropic dope in which an aromatic polyamide is dissolved in a polar amide, immersing the thin layer dope in a polar solvent kept at a temperature not higher than -20.degree. C. to coagulate the dope to form a film and drying the film in the presence of an isocyanate compound. Said process can produce directly a transparent film from an aromatic polyamide dope without requiring the step of dissolving the aromatic polyamide in conc. sulfuric acid, does not require any acid resistant equipment and is inexpensive.

Process for producing aromatic polyamide film

A process for producing an aromatic polyamide film, which comprises the steps of: (a) forming a thin layer of an optically isotropic dope in which an aromatic polyamide is dissolved in a polar amide, (b) immersing the thin layer dope of aromatic polyamide in a polar solvent, other than said polar amide, kept at a temperature not higher than -20.degree. C. to prepare a film, and (c) drying the film. The aromatic polyamide film thus obtained is excellent in transparency. Said process requires neither a step of dissolving an aromatic polyamide in conc. sulfuric acid nor an acid-resistant equipment, and hence, is inexpensive.

Thermoplastic resin composition and preparation thereof

Aromatic oligomer and process for preparing the same

Thermoplastic graft copolymer and process for preparing the same

Thermoplastic elastomer composition

An optical device comprising a mixture of a polymer constituted mainly of aromatic vinyl monomer units and polyphenylene ether, characterized in that the average molecular weight of the polyphenylene ether is from 0.3 to 0.7 expressed in terms of the intrinsic viscosity measured in chloroform at 25.degree. C.

Optical device

A polyether-polyamide block copolymer having an ethylenically unsaturated group represented by formula (I): ##STR1## wherein symbols are as defined in the specification; and a polyether prepolymer represented by formula (II): ##STR2## wherein the symbols are as defined in the specification, which is a starting material for synthesizing the above polyether-polyamide block copolymer, are disclosed. The polyether-polyamide block copolymer exhibits improved heat stability while retaining excellent characteristics inherent to polyether-polyamide.

Polyether-polyamide block copolymer and polyether prepolymer

A process for the production of formed articles of aromatic vinyl resin having a small birefringence and a high refractive index by a cast polymerization process rapidly and with high productivity, wherein the formed articles of aromatic vinyl resin are light and useful for the production of various optical elements such as lenses and prisms.

Process for the production of formed article of aromatic vinyl resin

Optical devices such as optical disk substrates and lenses are prepared by molding a resin composition comprising 100 parts by weight of a mixture of 30 to 70% by weight of a polymer in which 50% by weight or more is composed of aromatic vinyl monomer units and 70 to 30% by weight of a polyphenylene ether, and 0.005 to 2 parts by weight of an organic carboxylic acid.

Magneto optical disk substrate comprising an aromatic vinyl monomer and

A method for producing a polyether-polyamide block copolymer is disclosed, comprising copolymerizing, in the presence of an anionic polymerization catalyst, a lactam and a polyether prepolymer presented by the formula: ##STR1## wherein R.sup.1 is an aliphatic hydrocarbon residual group having 2 to 6 carbon atoms, R.sup.2 is an aliphatic hydrocarbon residual group having 3 to 12 carbon atoms, and n is an integer of 4 to 450. The polyester prepolymer is prepared by reacting a polyoxyalkylene having two terminal hydroxy groups with an N-chlorocarbonyl lactam. The polyether-polyamide block according to the invention has high impact strength and is substantially colorless.

Method of producing a polyether prepolymer

A process for producing a polyamide block copolymer is disclosed, which comprises suspension polymerizing a lactam in an organic suspending medium in the presence of an anionic polymerization catalyst and a polymer activator. The polyamide block copolymer obtained has a granular or powdery form easy to handle.

Process for producing polyamide block copolymer

A novel star block copolymer represented by the general formula as shown below and a process for the production thereof are described. The copolymer has superior physical properties, particularly impact strength and, furthermore, is reduced in coloration. Thus the copolymer can find numerous uses; for example, it can be used in preparation of fibers, foams, automotive parts, and electrical components. The copolymer is produced by copolymerizing a star-shaped polyether prepolymer and a lactam, said prepolymer being prepared by reacting a star-shaped polyoxyalkylene having at least 3 terminal hydroxy groups and an N-chlorocarbonyl lactam, in the presence of an anionic polymerization catalyst. ##STR1## In this formula, all the symbols are as defined hereinbefore.

Star block polyol lactam copolymer and process for the production thereof

Star block copolymer from lactam and polyol and process for the

The invention is to provide the methods for producing highly water-absorbable and water-retainable hydrogels having a large particle diameter together with a sufficient gel strength. The method is characterized by use of a specific dispersing agent in the water-in-oil type inverse phase suspension polymerization of an .alpha.,.beta.-unsaturated carboxylic acid and/or its alkali metal salt. Due to the high water-absorbability and water-retainability, along with the superior gel strength and the stable gel structure, the hydrogels of the invention enlarge the conventional range of usages.

Production of hydrogels

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Tsukuba, Japan

Masahiro Niwano