Sumitomo Seika Chemicals Co., Ltd.

Seitetsu Kagaku Co., Ltd.

Other

Masato Fujikake

Morio Nakamura

Shigeki Hamamoto

Shinji Kobayashi

Nobutaka Fujimoto

Tomoki Kawakita

Mitsutaka Tabata

Yasuhiro Nawata

Takushi Yamamoto

Shigeji Obayashi

Koji Ueda

Katsunori Tanaka

Masayoshi Handa

Masatoyo Yoshinaka

Masahiro Suzuki

Takao Okada

Takayasu Taniguchi

Kimihiko Kondo

Magoto Shirakawa

Masakazu Yamamori

Shioko Yoshinaka

The present invention relates to a crosslinked poly(meth)acrylic acid nitroxide compound resulting from crosslinking of a poly(meth)acrylic acid nitroxide compound, and an object of the present invention is to provide a method of inexpensively and easily producing a crosslinked poly(meth)acrylic acid nitroxide compound having a high radical concentration. The present invention is a method of producing a crosslinked poly(meth)acrylic acid nitroxide compound including a repeating unit represented by the general formula (2): (in the formula, R represents a hydrogen atom or a methyl group), comprising a nitroxidation step carried out in a state that a crosslinked poly(meth)acrylic acid imino compound resulting from crosslinking of a poly(meth)acrylic acid imino compound including a repeating unit represented by the general formula (1): (in the formula, R represents the same group as that represented by R in said general formula (2)) is dispersed in water.

Process for production of crosslinked poly(meth) acrylic acid nitroxide compounds

It is an object of the invention to provide a method of producing a crosslinked poly(meth)acrylic acid compound, in particular a method of producing a crosslinked poly(meth)acrylic acid nitroxide compound, which is a radical compound excellent in solvent stability. The invention is a method of producing a crosslinked poly(meth)acrylic acid compound resulting from crosslinking of a poly(meth)acrylic acid compound represented by the general formula (1): (in the formula, n Zs represent a hydrogen atom(s) and/or an oxygen atom(s) having one unpaired electron, R represents a hydrogen atom or a methyl group and n represents an integer of 5 to 1000000), (in the formula, Zrepresents a hydrogen atom when Zis a hydrogen atom, or a hydrogen atom or an oxygen atom having one unpaired electron when Zis an oxygen atom having one unpaired electron; and R represents the same group as R in the above general formula (1)) in the presence of a crosslinking agent.

Method for producing crosslinked poly(meth)acrylate compound

A process for preparing a water-absorbent resin made from an &#x3b1;,&#x3b2;-unsaturated carboxylic acid as an essential monomer characterized in that the process comprises allowing a metal chelating agent to be present at any step in the process in an amount of 0.001 to 6 parts by weight, based on 100 parts by weight of the &#x3b1;,&#x3b2;-unsaturated carboxylic acid; and adding a reducing agent or an oxidizing agent thereto in an amount of 0.001 to 6 parts by weight, based on 100 parts by weight of the &#x3b1;,&#x3b2;-unsaturated carboxylic acid before initiation of drying and/or during drying of a gelated product containing a water-absorbent resin obtained by polymerization.

Process for producing water-absorbing resin

A carboxyl group-containing polymer composition comprising 100 parts by weight of a carboxyl group-containing polymer (A) prepared by copolymerizing an &#x3b1;,&#x3b2;-unsaturated carboxylic acid (a) with a compound (b) having at least two ethylenic unsaturated groups; and 0.01 to 20 parts by weight of at least one compound (B) selected from an ester (c) obtained from a polyhydric alcohol and a fatty acid, and an alkylene oxide adduct of an ester (d) obtained from a polyhydric alcohol and a fatty acid. Since the carboxyl group-containing polymer composition is excellent in the solubility in water and gives the aqueous solution excellent thickening property, the polymer composition can be suitably used as a thickener for various aqueous solutions.

Carboxylated polymer composition

A polymer composition containing carboxyl group which is excellent in water solubility, thickening properties and flow characteristics. This composition comprises (A) a cross-linked polymer comprising (a) an &agr;,&bgr;-unsaturated carboxylic acid and (b) a compound having at least two ethylenically unsaturated groups, and (B) at least one polymer selected from among polymers comprising vinylpyrrolidone as an essential monomer and polyethylene oxide.

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 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

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.

Growing community of inventors

Himeji, Japan

Masato Fujikake