Unitika Ltd.

Nippon Steel Corporation

Toda Kogyo Corporation

Nippon Steel Chemical Co., Ltd.

Souichiro Kishimoto

Yoshiaki Echigo

Eiichi Kurita

Toshiyuki Hakata

Kazuo Fujioka

Shigeru Takaragi

Masao Kimura

Keiichi Asami

Tetsuro Toda

Hiroshi Ohishi

Takumi Tanaka

Koichi Fujishiro

Masanao Kawabe

Tsutomu Sakaida

Tomohiro Hamada

Shinji Inaba

Keizo Kyuda

Akio Motoyama

Takamasa Owaki

Akihiko Hasegawa

Shinya Takagi

Takamasa Ohwaki

A resin for coating formation which comprises a polyarylate comprising 2,2-bis(3-methyl-4-hydroxyphenyl)propane units and a divalent carboxylic acid component comprising 10 to 90 mol % of terephthalic acid units and 90 to 10 mol % of isophthalic acid units, having an inherent viscosity measured in 1,1,2,2-tetrachloroethane at a concentration of 1 g/dl at 25.degree. C. of 0.85 or more, and having a carboxyl value of 20 mol/ton or less. Also disclosed is a process for producing the resin by interfacial polymerization, using a quaternary ammonium salt or a quaternary phosphonium salt having at least 3 alkyl groups each having at least 3 carbon atoms as a catalyst.

Resin for coating formation and method for producing the same

A process is disclosed for preparing of aromatic polyester-polystyrene block copolymers which comprises subjecting preferentially styrene polymers (A) having terminal functional groups reactive with acid chloride groups and an excess of aromatic dicarboxylic acid dihalides (C) to condensation and then subjecting continuously the resultant mixture and aromatic dihydroxy compounds (B) to interfacial polymerization at the ratio (A)/[(B)+(C)] by weight of 5/95 to 80/20, without separating reaction products of styrene polymers (A) and aromatic dicarboxylic acid dihalides (C), and the block copolymers thus prepared contain a small amount of uncopolymerized styrene polymers, have long aromatic polyester segments, show low birefringence, good transparency, exceptionally low birefringence, low melt viscosity, and good mechanical strength, and are particularly useful as materials for optical instruments.

Process for preparing aromatic polyester-polystyrene block copolymers

Disclosed herein are composite carrier particles for electrophotography comprising 80 to 99% by weight of ferromagnetic fine particles and a phenol resin, and having a number-average particle diameter of 10 to 1,000 .mu.m, a bulk density of not more than 2.0 g /cm.sup.3, and a curved surface configuration, and a process for producing the same.

Composite carrier particles for electrophotography and process for

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Ohnojyo, Japan

Souichiro Kishimoto