Nippon Shokubai Co., Ltd.

Nippon Shokubai Kagaku Kogyo Co., Ltd.

Takumi Hatsuda

Yoshio Irie

Katsuhiro Kajikawa

Kunihiko Ishizaki

Koji Miyake

Tadao Shimomura

Kazuki Kimura

Kazumasa Kimura

Katsuyuki Wada

Kinya Nagasuna

Yasuhiro Fujita

Akito Yano

Yorimichi Dairoku

Masatoshi Nakamura

Teruaki Fujiwara

Kazuhisa Hitomi

Toru Yanase

Nobuyuki Harada

Shinichi Fujino

Soichi Yamada

Hideyuki Tahara

Hiroko Ueda

Yoshihiro Motono

Kazumasa Konishi

Teruyuki Kanto

Koichi Yonemura

Naoko Takahashi

Hitoshi Takahashi

Hiroyuki Kakita

Jyunichi Saga

Tatsuo Maruo

Hiroyuki Ikeuchi

Yoshifumi Adachi

Yoshihiko Masuda

Tsuneo Tsubakimoto

Sumio Okuda

Takashi Namba

Eri Goto

Takanori Murakami

Kaoru Iwasaki

Takashi Nishigaki

Sachio Fujita

Masatoshi Nakamuta

The present invention provides: a water-absorbing agent which has excellent urine resistance; a water-absorbing agent which has not only excellent urine resistance, but also excellent absorption properties that are stable to any composition of urine and show little change with time; and production processes and uses for these water-absorbing agents. The present invention water-absorbing agent exhibits a specific or larger value of absorption capacity under a load in a process in which the absorption capacity under a load is measured in a new manner using a specific liquid to be absorbed, and the present invention provides an absorbent matter and an absorbent article which display a specific or larger value of new absorption index as is, for example, led from the absorption capacity under a load or from the resin concentration using the above water-absorbing agent. The present invention further provides a production process for a water-absorbing agent having the above specific parameter.

Water-absorbing agent production process with surface crosslinking and ion blocking

In a production process for a water-absorbent resin, comprising the steps of: blending a liquid material and a water-absorbent resin; and heating the resultant mixture in order to produce a modified water-absorbent resin, the present invention is to provide: a method for uniformly and efficiently treating a water-absorbent resin favorably in view of industry, and as a result, a good-balanced water-absorbent resin having various excellent properties, such absorption capacity without a load, absorption capacity under a load, and single-layer absorption capacity under a load in contact with an aqueous liquid. The production process comprises the step of spray-blending a water-absorbent resin (A) and a liquid material (B) with a blending apparatus equipped with a spray nozzle (C), wherein the liquid material (B) is sprayed from the spray nozzle (C) and its spray pattern is a circular and hollow cone shape or a double-convex-lens and elliptic cone shape. In addition, the production process comprises the step of heat-treating a water-absorbent resin under an atmosphere having a dew point of not higher than 60&#xb0; C. and a temperature of not lower than 90&#xb0; C., wherein the water-absorbent resin is obtained after a drying step following a pulverization step.

Water-absorbent resin and production process therefor

The invention provides: a water-absorbent resin granule-containing composition with resolution of various problems, as caused by water-absorbent resin fine powders, and with high granulation strength, and with no physical property deterioration due to granulation, and, if anything, with improvement of the absorption capacity under a load by granulation; and a process for producing the above granule. A water-absorbent resin primary particle and a water-absorbent resin granule are separately surface-crosslinked and then mixed, or mixed and then surface-crosslinked. The granulation is carried out by mixing a preheated aqueous liquid and a water-absorbent resin powder at a high speed or by supplying a water-absorbent resin powder downstream of an aqueous liquid with a continuous extrusion mixer.

Water-absorbent resin granule-containing composition and production process for water-absorbent resin granule

In the production of an acrylate polymer by the steps of preparing a water-soluble unsaturated monomer having a ratio of neutralization in the range of 30 to 100 mol % and containing 50 to 100 mol % of an acrylate and then polymerizing the monomer, a method for the production of a hydrophilic resin which comprises using a water-soluble unsaturated monomer having a &#x3b2;-hydroxy propionic acid (salt) content of not more than 1,000 ppm. The hydrophilic resin obtained by this method exhibits excellent physical properties and has only a small residual monomer content. Further, a residual monomer content neither occurs nor increases in any using conditions.

Method for production of hydrophilic resin

The present invention provides: a process for treating a particulate water-absorbent resin, which enables to carry out pulverization stably in a process for producing a particulate water-absorbent resin, and transportation or storage of the particulate water-absorbent resin stably during or after producing the particulate water-absorbent resin, and to prevent contamination of cohered matters of the particulate water-absorbent resin; and involves no or little deterioration of properties. The process for treating a particulate water-absorbent resin is characterized by carrying out at least one selected from the group consisting of: (1) heating at least one portion of a surface getting contact with the particulate water-absorbent resin from the outside, (2) maintaining the temperature of at least one portion of a surface getting contact with the particulate water-absorbent resin at 30 to 150&deg; C., and (3) maintaining the temperature of at least one portion of a surface getting contact with the particulate water-absorbent resin above a temperature that is lower than a temperature of the particulate water-absorbent resin by 20&deg; C.

Process for transporting, storing, and producing a particulate water-absorbent resin

In a production process for a water-absorbent resin, comprising the steps of: blending a liquid material and a water-absorbent resin; and heating the resultant mixture in order to produce a modified water-absorbent resin, the present invention is to provide: a method for uniformly and efficiently treating a water-absorbent resin favorably in view of industry, and as a result, a good-balanced water-absorbent resin having various excellent properties, such absorption capacity without a load, absorption capacity under a load, and single-layer absorption capacity under a load in contact with an aqueous liquid. The production process comprises the step of spray-blending a water-absorbent resin (A) and a liquid material (B) with a blending apparatus equipped with a spray nozzle (C), wherein the liquid material (B) is sprayed from the spray nozzle (C) and its spray pattern is a circular and hollow cone shape or a double-convex-lens and elliptic cone shape. In addition, the production process comprises the step of heat-treating a water-absorbent resin under an atmosphere having a dew point of not higher than 60&deg; C. and a temperature of not lower than 90&deg; C., wherein the water-absorbent resin is obtained after a drying step following a pulverization step.

Continuous manufacturing method of water-absorbent polymer

Water-absorbing agents containing polycarboxylic amine chelating agents. The water-absorbing agents are obtained by a process including the step of adding to a water-absorbent resin at least one chelating agent selected from the group consisting of polycarboxylic amines and maleic hydrophilic polymers. The polycarboxylic amine may be selected from a class that includes N-carboxymethyl-aspartic acid as one of its members or selected from a class that includes N,N&prime;-bis(1,2-dicarboxyethyl)-ethylenediamine as one of its members. The water-absorbing agents have not only excellent urine resistance, but also excellent absorption properties that are stable to any composition of urine and show little change with time.

Water-absorbent agents containing polycarboxylic amine chelating agents

The present invention provides: a water-absorbing composition such that portions containing the water-absorbing composition in a high concentration exhibit excessive-liquid permeation buffering effects in absorbent articles comprising the water-absorbing composition and hydrophilic fibers; and a use of this water-absorbing composition. The water-absorbing composition comprises a water-absorbent resin and an excessive-liquid permeation buffer, wherein the water-absorbent resin is a product by a process including the step of further crosslinking the surface vicinity of a crosslinked polymer, and this water-absorbing composition is characterized by having a liquid permeation buffering index of not less than 0.4 and exhibiting an absorption capacity of not less than 25 g/g in absorbent structures under load, and further having an average particle diameter in the range of 200&tilde;600 &mgr;m, wherein the ratio of particles having particle diameters smaller than 106 &mgr;m in the water-absorbing composition is not more than 5 weight %. This water-absorbing composition is, for example, used for the absorbent articles comprising the water-absorbing composition and the hydrophilic fibers.

Water-absorbing composition and its use

The present invention provides a production process for a water-absorbent resin powder which is excellent in particle diameter distribution and properties, wherein the production process not only inhibits adhesion and aggregation in the production steps, but also is excellent in energy efficiency, drying efficiency, and productivity. The production process for a water-absorbent resin powder comprises the steps of: polymerizing an aqueous monomer solution containing a crosslinking agent; heat-drying the resultant crosslinked hydrogel polymer; and pulverizing the resultant dry polymer; wherein: the dry polymer resultant from the heat-drying step is forcibly cooled before or during the pulverization step; and the water-absorbent resin powder has an average particle diameter of 200 to 600 &mgr;m after the pulverization step wherein the total ratio of particles having particle diameters of not larger than 150 &mgr;m and particles having particle diameters of not smaller than 850 &mgr;m in the water-absorbent resin powder is not more than 15 weight % of the water-absorbent resin powder.

Water-absorbent resin powder and production process therefor

The present invention provides a water-absorbent resin powder and its production process and use, wherein the water-absorbent resin powder has high liquid permeability and high water absorbency. The production process for a water-absorbent resin powder, according to the present invention, comprises the step of obtaining water-absorbent crosslinked polymer particles by an aqueous solution polymerization step, and grinding the resultant crosslinked polymer particles until the bulk density thereof increases to not lower than 0.72 (g/ml). The water-absorbent resin powder is characterized by being arbitrarily pulverized and having a bulk density of not lower than 0.74 (g/ml) and a water absorption capacity of not lower than 20 (g/g) for 0.9 weight % physiological saline under a load of 0.7 psi (4.83 kPa). In addition, the absorbent structure comprises the above water-absorbent resin powder and a fibrous material. The absorbent article comprises an absorbent layer including the above absorbent structure.

Water-absorbent resin powder and its production process and use

In the production of an acrylate polymer by the steps of preparing a water-soluble unsaturated monomer having a ratio of neutralization in the range of 30 to 100 mol % and containing 50 to 100 mol % of an acrylate and then polymerizing the monomer, a method for the production of a hydrophilic resin which comprises using a water-soluble unsaturated monomer having a &bgr;-hydroxy propionic acid (salt) content of not more than 1,000 ppm. The hydrophilic resin obtained by this method exhibits excellent physical properties and has only a small residual monomer content. Further, a residual monomer content neither occurs nor increases in any using conditions.

A manufacturing method of absorbent resin of the present invention includes, in addition to a drying step of drying hydrogel of a crosslinked polymer to obtain a dried product and a pulverizing step of pulverizing the dried product, a separating step of separating a incompletely dried product contained in the dried product therefrom. Since particles of the incompletely dried product are larger than those of the dried product, the former can be readily separated from the latter in the separating step by classifying the dried product to particles of a particle size within a predetermined range. Consequently, the incompletely dried product is never delivered to the pulverizing step, and therefore, it has become possible to prevent inconveniences, such as causing a trouble in pulverizing the dried product, and the incompletely dried product being mixed into the absorbent resin. Hence, in drying and subsequently pulverizing the hydrogel of a crosslinked polymer, that is, in manufacturing the absorbent resin, it has become possible to provide a method capable of manufacturing absorbent resin efficiently while avoiding troubles caused by the production of the incompletely dried product during the drying step.

Manufacturing method of absorbent resin

Growing community of inventors

Takasago, Japan

Takumi Hatsuda