Seitetsu Kagaku Co., Ltd.

Sumitomo Seika Chemicals Co., Ltd.

Other

Morio Nakamura

Takushi Yamamoto

Shigeji Obayashi

Hitoshi Tanaka

Masato Fujikake

Yuji Sakamoto

Shinji Kobayashi

Shigeki Hamamoto

Shinichi Takemori

Yasuhiro Shimada

Katsunori Tanaka

Nobutaka Fujimoto

Yasuhiro Nawata

Hitoshi Ozawa

Nobuhiro Maeda

Masahiro Suzuki

Takao Okada

Kimihiko Kondo

Mitsutaka Tabata

Koichi Fujiki

Tetsurou Motooka

Kosaku Yamada

Hiroari Hara

Motomu Hirakawa

Magoto Shirakawa

Toshikazu Nakanishi

Masakazu Yamamori

Shioko Yoshinaka

A process for preparing a water-absorbent resin is provided which enables the water-absorbent resin to ensure the reduction in the release amount of liquid and the increase in the liquid diffusibility. In the preparation process, the water-absorbent resin is prepared by polymerization of a water-soluble ethylenic unsaturated monomer. The polymerization of the water-soluble ethylenic unsaturated monomer is allowed to take place in the presence of a water-absorbent resin having a water-absorbing rate different from that of a water-absorbent resin resulting from polymerization of the water-soluble ethylenic unsaturated monomer. In a preferred mode, the polymerization is performed by a reversed-phase suspension polymerization method.

Process for preparing water-absorbent resin

A method for producing a highly concentrated aqueous acrylic amide-based polymer dispersion which is inexpensive, good in fluidity and easy to handle is provided. The method comprises polymerizing a water-soluble monomer composition containing an acrylic amide monomer in an aqueous solution of an inorganic salt in the presence of a homopolymer of vinylpyrrolidone and/or a copolymer of vinylpyrrolidone and other monomer(s).

Aqueous polymerization of acrylamide in the presence of polyvinylpyrrolidone

There is provided an industrially advantageous process for producing a crosslinked polymer containing carboxyl groups which comprises (a) polymerizing an .alpha.,.beta.-unsaturated carboxylic acid and a crosslinking agent copolymerizable with it in the presence of a radical polymerization catalyst in an inert solvent, (b) heating the polymerized product in the presence of a radical scavenger and (c) removing the solvent. The polymer dissolved in water has high viscosity and excellent flowing properties.

Process for producing cross-linked polymer containing carboxyl group

The present invention is directed to a method for production of a water-soluble cationic polymer comprising polymerizing a cationic vinyl monomer; either a cationic acrylate monomer alone or a mixture of said monomer and another monomer copolymerizable therewith, in dispersion medium in the presence of a surfactant by suspension polymerization method. The present invention offers an industrially advantageous method to obtain the water-soluble cationic polymer with a high degree of cationization and a high viscosity in water solution which can be used for flocculants, antistatic agents, retention aids for paper manufacturing and other purposes.

Method for production of water-soluble cationic polymer

The present invention is directed to a method for production of alkylene oxide polymers comprising reacting an alkylene oxide in an inert hydrocarbon solvent in the presence of a catalyst. The method of the present invention offers alkylene oxide polymers with a great commercial value and a high degree of polymerization which can be produced industrially advantageously with high reproducibility by the use of a catalyst obtained by a simple procedure of applying heat treatment to the product obtained by reacting an organic zinc compound with particular aliphatic polyhydric alcohol and monohydric alcohol.

Method for production of alkylene oxide polymers

An improved process for the production of a water-absorbent resin by reversed phase suspension polymerization of a water-soluble ethylenic unsaturated monomer is disclosed. The process is conducted by subjecting an aqueous solution of a water-soluble ethylenic unsaturated monomer to reversed phase suspension polymerization reaction of a first stage in a petroleum hydrocarbon solvent in the presence of a surfactant and/or polymeric protective colloid by using a radical polymerization initiator optionally in the presence of a crosslinking agent, cooling the resulting slurry to precipitate the surfactant and/or polymeric protective colloid, and adding an aqueous solution of a water-soluble ethylenic unsaturated monomer containing a radical polymerization initiator and optionally a crosslinking agent to the first polymerization reaction system to further carry out the reversed phase suspension polymerization reaction, at least, once.

Process for production of water-absorbent resin

A water retention material with water-absorbency which comprises finely divided particles of water-absorbent resin having a water absorption capacity of 2 to 50-fold and a particle size of 100.mu. or finer and a hydrophobic material such as a thermoplastic resin, elastomer, sealant, paint or adhesive.

Water retention material with water-absorbency

A water-absorbent resin composition having superior gel stability which comprises a water-absorbent resin, at least one oxygen-containing reducing inorganic salt and, optionally, at least one organic antioxidant.

Water-absorbent resin composition

A water-absorbent resin having excellent physical properties can be produced by a process wherein an aqueous solution containing an .alpha.,.beta.-unsaturated carboxylic acid and an alkali metal salt thereof in a total amount of 25% by weight or more is subjected to polymerization with a radical polymerization initiator in a petroleum-based hydrocarbon solvent in the presence or absence of a crosslinking agent, characterized by using, as a surfactant, a polyglycerine--fatty acid ester having an HLB of 2 to 16 and represented by the general formula ##STR1## (wherein R is an acyl group or hydrogen atom and n is an integer of 0 to 8).

Process for producing a water-absorbent resin

A water-absorbent resin having an appropriate particle size and a narrow particle size distribution can be obtained by adding a powdered inorganic material in a proportion of 0.000005-0.2 part by weight to 1 part by weight of a water-absorbent resin containing therein a carboxylate as a component of the polymer with agitation in an inert solvent in the presence of 0.1-5.0 parts by weight of water and 0.005-0.2 part by weight of a surfactant and then removing water and the inert solvent by distillation.

Process for granulating a water-absorbent resin employing (a) water (b)

A water-absorbent resin usable as a suitable water absorbent in sanitary materials and other fields can be produced by subjecting an aqueous solution of an .alpha.,.beta.-unsaturated carboxylic acid and of an alkali metal salt thereof to polymerization with a radical polymerization initiator in a petroleum-based hydrocarbon solvent in the presence or absence of a crosslinking agent and, in this polymerization, using a saccharose-fatty acid ester as a protective colloid agent.

Water-swellable elastomer composition consisting essentially of a homogeneous mixture of an elastomer, a water-absorbent resin and a water-soluble resin. Said composition exhibits a high degree of swelling and a high swelling rate when it is soaked in water. Also, said composition retains swellability even when it is put in contact with water for a long period of time.

Water-swellable elastomer composition

Water-absorbent resins having improved water-absorbency, water-absorption rate and water-dispersibility can be produced by crosslinking a water-absorbent resin comprising a carboxylate as a constituent of the resin with a crosslinking agent having at least two functional groups in the presence of water in a proportion of 0.01 to 1.3 parts by weight per part by weight of the resin in an inert solvent.

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Himeji, Japan

Morio Nakamura