Arakawa Kagaku Kogyo Kabushiki Kaisha

Muneharu Makita

Shozo Tanioku

Osamu Oseto

Jun-ichi Maeno

Toshiaki Munemitsu

A process for preparing a highly water-absorbent resin by a reversed-phase suspension polymerization method using an aqueous solution of a monomer containing an alkali metal salt of acrylic or methacrylic acid, water-soluble polymerization initiator, protective colloid, hydrophobic organic solvent and if required, dispersing agent, the process being characterized in that the protective colloid is a copolymer comprising: (A) about 50 to about 97 mole % of styrene and/or alkyl-substituted derivative thereof, (B) 0 to about 50 mole % of dialkylaminoalkyl acrylate or methacrylate and/or dialkylaminoalkyl acrylamide or methacrylamide, (C) about 3 to about 15 mole % of glycidyl acrylate and/or glycidyl methacrylate and (D) 0 to about 30 mole % of an unsaturated monomer which can be copolymerized with the component A, B or C.

Process for preparing highly water-absorbent resin

A method for easily, inexpensively and efficiently producing an improved water-absorbent resin having a high water absorbency and a high water absorption rate and capable of forming a gel having a high gel strength and nonstickiness, in which water-absorbent resin particles which contain water and a crosslinking agent and are in the semi-swollen state are agitated at an elevated temperature in the presence of an inert inorganic powder to conduct the crosslinking of the resin, while removing water, the water-absorbent resin containing a monomer units having a carboxyl group in the form of free acid or a metal salt.

Method for producing improved water-absorbent resins

An electrophotographic toner composition having excellent blocking resistance and offset resistance which contains as a resin binder a polymeric rosin compound having a softening point of 50.degree. to 190.degree. C., a glass transition temperature of 10.degree. to 170.degree. C. and a molecular weight of 2,000 to 40,000 prepared by the reaction of (a) a glycidyl ester of rosin, (b) a dicarboxylic acid or its anhydride, and (c) a crosslinking agent selected from the group consisting of a polyfunctional epoxy compound, a polycarboxylic acid having a valency of not less than 3 or its anhydride, and a polyhydric alcohol having a valency of not less than 3. A dihydric alcohol may be used in the above reaction in order to improve the low temperature fixing property of the toner.

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Takatsuki, Japan

Muneharu Makita