Nippon Shokubai Co., Ltd.

Nippon Shokubai Kagaku Kogyo Co., Ltd.

Yoshio Irie

Yorimichi Dairoku

Kunihiko Ishizaki

Takumi Hatsuda

Teruaki Fujiwara

Shinichi Fujino

Tadao Shimomura

Yasuhiro Fujita

Katsuhiro Kajikawa

Katsuyuki Wada

Kozo Nogi

Shigeru Yamaguchi

Shigeru Sakamoto

Hirofumi Shibata

Kinya Nagasuna

Kazumasa Kimura

Yoshihiko Masuda

Kenji Tada

Tsuneo Tsubakimoto

Hitoshi Takahashi

Takashi Azumi

Koji Miyake

Sayaka Machida

Yoshiro Mitsukami

Hiroki Inoue

Makoto Nagasawa

Shorbu Shioji

Keishi Tsuboi

Kazushi Torii

Nobuyuki Harada

Hiroyuki Ikeuchi

Kenji Kadonaga

Yoshifumi Adachi

Kazuki Kimura

Taku Iwamura

Masazumi Sasabe

Hideyuki Tahara

Masatoshi Nakamura

Hiroko Ueda

Shin-Ichi Fujino

Koichi Yonemura

Takaaki Kawano

Hiroyuki Kakita

Kazutaka Yano

Kaoru Iwasaki

Jyunichi Saga

Makoto Matsumoto

Hiroshi Ito

Yasuhisa Nakashima

Seiji Kato

Akito Yano

Hideaki Nagano

Masahito Takagi

Hiroko Okochi

Tomoki Gomi

Atsushi Motoyama

Tokihiro Yokoi

Tatsuo Maruo

Kazumi Akihisa

Shigeyasu Morihiro

Yoshinobu Haruna

Teruaki Fujihara

Kohichi Hirota

Hideyuki Kubo

Masatoshi Nakamuta

The present invention provides a method for producing a water absorbent resin particle, in high productivity, not only in a controlled manner of particle size but also enhancing fundamental property (absorption capacity or absorption capacity against pressure) of a water absorbent resin. A method for producing a water absorbent resin particle having the cross-linking polymerization step for an aqueous solution of an unsaturated monomer; the grain refining step for water-swellable, water-containing gel-like cross-linked polymer (a) obtained in the cross-linking polymerization step; the drying step for grain refined gel; and the crushing step for a dried substance, wherein, in the grain refining step for the water-swellable, water-containing gel-like cross-linked polymer (a), water-swellable, water-containing gel-like cross-linked polymer (b), having solid content or centrifuge retention capacity different from solid content or centrifuge retention capacity of the cross-linked polymer (a) by equal to or larger than 1%, is subjected to coexistence.

Method for producing water absorbent resin particle

A method for producing a polyacrylic water-absorbent resin powder includes the steps of: producing an acrylic monomer solution in which gas is dissolved and/or dispersed; polymerizing the monomer solution in the absence of a surface active agent or in the presence of not more than 300 ppm of a surface active agent; during or after polymerizing, fragmenting the resulting hydrated gel crosslinked polymer; and drying the fragmented hydrated gel crosslinked polymer. The gas is dissolved and/or dispersed in the monomer solution by (a) applying pressure to the acrylic monomer solution and the gas; (b) creating swirling flows of the acrylic monomer solution and the gas; or (c) introducing the gas with the acrylic monomer solution via fine holes. The production method efficiently produces a water-absorbent resin having an excellent water-absorption rate without deteriorating a liquid-absorbent property of a sanitary product or the like.

Polyacrylic acid-based water-absorbing resin powder and method for producing the same

The present invention is to provide a drying method by which both cost reduction and superior physical properties can be attained in a step which comprises subjecting a water-containing gel-like crosslinked polymer obtained by polymerizing an aqueous monomer solution to fine granulation during or after the polymerization, and drying the resultant particulate water-containing gel-like crosslinked polymer with a through-circulation band dryer. The method has a feature in that the drying conditions over a period from a time of introducing the particulate water-containing gel-like crosslinked polymer into a drying zone of the through-circulation band dryer to a time of reaching a solid content concentration thereof to 80% by weight, satisfy that (1) a difference of temperature between a temperature of hot air blown to a particulate hydrogel layer and a temperature measured after the hot air passes through the particulate hydrogel layer is 20 to 70&#xb0; C.

Method for drying granular water-containing gel-like cross-linked polymer

A method for producing a polyacrylic water-absorbent resin powder includes the steps of: producing an acrylic monomer solution in which gas is dissolved and/or dispersed; polymerizing the monomer solution in the absence of a surface active agent or in the presence of not more than 300 ppm of a surface active agent; during or after polymerizing, fragmenting the resulting hydrated gel crosslinked polymer; and drying the fragmented hydrated gel crosslinked polymer, the gas being dissolved and/or dispersed in the monomer solution by (a) applying pressure to the acrylic monomer solution and the gas; (b) creating swirling flows of the acrylic monomer solution and the gas; or (c) introducing the gas with the acrylic monomer solution via fine holes. The production method efficiently produces a water-absorbent resin having an excellent water-absorption rate without deteriorating a liquid-absorbent property of a sanitary product or the like.

Polyacrylic water-absorbent resin powder and method for producing the same

The present invention provides a surface treatment method for a water-absorbing resin comprising three steps of:

Surface treatment method for water-absorbing resin and production method for water-absorbing resin

The present invention provides a production process by which a water-absorbent resin of excellent quality can be obtained at a low cost by reasonable steps in aqueous solution polymerization. The process for producing a water-absorbent resin comprises the step of polymerizing an aqueous solution of water-absorbent resin-forming monomers including acrylic acid and/or its sodium salt as major components, wherein: (1) the aqueous solution has a monomer component concentration of not less than 45 weight %; (2) the polymerization is carried out while water is evaporated so that the ratio (concentration ratio) between a solid component concentration in a hydropolymer as formed by the polymerization and a solid component concentration in the aqueous monomer solution will not be less than 1.10; and (3) the solid component concentration in the hydropolymer as formed by the polymerization is not more than 80 weight %.

Water-absorbent resin, hydropolymer, process for producing them, and uses of them

An object of the present invention is to provide a water absorbent having excellent gel properties and showing excellent properties when used in a water-absorbing material of a sanitary/hygienic material such as paper diaper. Moreover, another object of the present invention is to provide a water absorbent which is safe and excellent in liquid permeability, and in which an amount of liquid permeability improver for improving the liquid permeability is reduced. The water absorbent is made from a water-absorbing resin prepared by a specific polymerization method and having a high degree of cross-linking, a high liquid holding property and a high gel strength (its swelling pressure of gel layer of is 35 kdyne/cm2 or more). This water absorbent is further processed to have a particular particle size distribution (95 wt % or more of its particles are less than 850&fnof;&#xca;m but not less than 106&fnof;&#xca;m, and logarithmic standard deviation (&fnof;&Dstrok;&fnof;&#xc4;) is in a range of 0.25 to 0.45) and then surface cross-linked. After that, a liquid permeability improver is added therein.

Water absorbent and producing method of same

A method for surface crosslinking water-absorbing resin of the present invention includes a step (1) of obtaining a wet mixture, a step (2) of obtaining a dried particulate composition, and a step (3) of carrying out a surface crosslinking reaction. With this, since a processing time of each step becomes short, it is possible to mass produce the water-absorbing resin having excellent physical properties. Moreover, a method for manufacturing the water-absorbing resin of the present invention includes a modifying step and a cooling step. The modifying step and/or the cooling step are/is carried out by using stirring means including a rotation axis having a plurality of stirring boards, and the stirring means includes the stirring board having a specific thickness and/or a scraping blade having a specific shape. With this, it is possible to suppress the generation of the fine powder in the modifying step and/or the cooling step.

Method for surface crosslinking water-absorbing resin and method for manufacturing water-absorbing resin

A water-absorbent composition includes: a specific plant extract; a water-absorbent resin whose surface portion and/or periphery thereof is treated; and/or a water-absorbent resin having a specific property. Specifically, it is preferable to use a water-absorbent resin having three characteristics: (1) a specific neutralization rate, (2) a specific particle diameter, and (3) a specific plant extract. The water-absorbent composition has a superior deodorant performance and an absorbent characteristic when the water-absorbent composition is used (provided) in an absorbing product such as a paper diaper, thereby providing a superior deodorant performance and a superior absorbent characteristic to the foregoing absorbing product.

Water-absorbent composition, process for production thereof, absorbent and absorbing product

The subject invention provides a hydrophilic polymer (water-absorbing resin) which is superior in performance and productivity. According to the production method of the present invention, a hydrophilichigh-molecular-weight compound is dispersed in an aqueous solution containing a hydrophilic monomer. The dispersed hydrophilic high-molecular-weight compound is dissolved by heat of neutralization (heat of hydration) and/or heat of polymerization generated in the process of producing a hydrophilic polymer.

Production method for hydrophilic polymer

A method for disintegrating a hydrate polymer characterized by disintegrating a hydrate polymer having a solid content in the range of 50-70 wt. % with a screw extruder while supplying 0.1-30 parts by weight of water per 100 parts by weight of the polymer to the extruder. Since the product of disintegration is prevented from inducing mutual adhesion, it does not form masses of conglomeration when it is dried.

Method for disintegrating hydrate polymer and method for production of water-absorbent resin

The present invention relates to a method for continuous production of a water-absorbent resin by use of an continuous polymerization device having a charge part of a monomer aqueous solution; an endless belt on which the monomer and a hydropolymer formed are conveyed; and a discharge part of the hydropolymer, wherein the continuous polymerization device has side walls and a ceiling, and the space ratio in the device represented by the equation, 'space ratio in the device=B/A', is in the range of 1.2 to 20. In the equation, A is a maximum cross-sectional area (cm) of the hydropolymer during the polymerization in the width direction of the endless belt, and B is a maximum cross-sectional area (cm) of the space between the endless belt of the continuous polymerization device and the ceiling of the continuous polymerization device in the width direction of the endless belt.

Method for continuous production of water-absorbent resin

The present invention has an object to provide a particulate water-absorbing composition, a production process therefor, and an absorbent article comprising this particulate water-absorbing composition, wherein the particulate water-absorbing composition causes little coloring of other materials and further is of high safety, and can provide excellent deodorizability and excellent absorption properties to absorbent articles such as diapers in the case where combined into the absorbent articles. As a means of achieving this object, a particulate water-absorbing composition according to the present invention is characterized by comprising a plant powder and a water-absorbent resin, wherein a surface portion and/or its vicinity of the water-absorbent resin is surface-treated with a crosslinking agent, and wherein the particulate water-absorbing composition exhibits an offensive-odor removal index of not less than 180 wherein the offensive-odor removal index is represented by the following equation: offensive-odor removal index=1.1&#xd7;hydrogen sulfide removal ratio+2.0&#xd7;methylmercaptan removal ratio+0.3&#xd7;ammonia removal ratio.

Water-absorbing agent composition and method for production thereof, absorptive article and absorbing material

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Himeji, Japan

Yoshio Irie