Nippon Shokubai Co., Ltd.

Nippon Shokubai Kagaku Kogyo Co., Ltd.

Nobuyuki Harada

Kunihiko Ishizaki

Yoshihiro Motono

Tadao Shimomura

Koji Miyake

Toshimasa Kitayama

Kinya Nagasuna

Shigeru Sakamoto

Kazumasa Kimura

Yorimichi Dairoku

Hirotama Fujimaru

Yoshifumi Adachi

Yoshihiko Masuda

Kazuhisa Hitomi

Teruyuki Kanto

Kazushi Torii

Katsuyuki Wada

Takumi Hatsuda

Hisanobu Obara

Hisanori Obara

Yoshio Irie

Kazuki Kimura

Toru Inaoka

Akito Yano

Koichi Yonemura

Hiroshi Odanaka

Shigenori Kirimura

Yoshinori Sano

Sei Nakahara

Hiroyuki Ikeuchi

Shinichi Fujino

Yasuhiro Fujita

Yuuji Shimasaki

Hideyuki Tahara

Masatoshi Nakamura

Shin-Ichi Fujino

Teruaki Fujiwara

Akio Naka

Hideaki Nagano

Hideyuki Nishibayashi

Akiko Mitsuhashi

Toshiaki Kuriyama

Toru Yanase

Daijo Tomihisa

Takaya Hayashi

Yuji Yamamoto

Kaoru Iwasaki

Toshihiro Okuno

Kohichi Hirota

Hideyuki Kubo

A particulate water retaining material for cultivating plant comprising (A) a carboxyl group-containing water-insoluble water absorbent resin and (B) a polyvalent metal compound, by having the compound (B) deposited on the rerin (A), it is made possible to possess an outstanding water absorbing property without impairing the growth of a plant.

Particulate water retaining material for cultivating plant having water absorbent resin as main component

The present invention provides: a novel water-absorbing agent, which exhibits an excellent absorption capacity under a load (AAP), gel layer liquid permeation rate under a load (FRUP), saline flow conductivity (SFC), and shape-maintaining property and ball burst strength (BBS) of a swollen water-absorbing agent aggregate, and excellent persistency of these effects for a long time. The water-absorbing agent, which comprises a polymer obtained by a process including the steps of polymerizing and then crosslinking a monomer including acrylic acid and/or a salt thereof, with the water-absorbing agent being characterized by: (1) exhibiting a free swelling capacity of not less than 23 g/g (GV), a gel deformation of not more than 12.5 cm under a short-time load (0.5 hrPT), and a gel deformation deterioration of not more than 3.5 cm under a load with the passage of time (&#x394;PT); (2) exhibiting a free swelling capacity of not less than 23 g/g (GV), a ball burst strength of not less than 80 gf (BBS), and a deterioration of ball burst strength of not more than 40% (DBBS); or (3) exhibiting a free swelling capacity of not less than 23 g/g (GV), an absorption capacity of not less than 20 g/g under a load of 4.9 kPa (AAP), and a gel deformation of not more than 12.5 cm under a load (16 hrPT).

Water-absorbing agent and production process therefor, and water-absorbent structure

A method for the production of a water-absorbent agent comprises mixing an absorbent resin containing a carboxyl group with an additive soluble in the aqueous solution of at least one member selected from the group consisting of inorganic acids, organic acids, and polyamino acids and a cross-linking agent capable of reacting with the carboxyl group. A water-absorbent agent obtained by adding from 0.005 to 8 parts by weight of an epoxy compound to 100 parts by weight of a water-absorbent resin, exhibiting an absorption capacity without load of at least 45 (g/g), an absorption capacity under load of 20 g/cmof not less than 30 (ml/g) and having a residue amount of an epoxy compound of not more than 2 ppm. A water-absorbent composition comprises a polyamino acid (salt) and a water-absorbent resin containing a carboxyl group.

Absorbent resin composition

Water-absorbent agent, method for production thereof, and water-absorbent composition

The present invention provides: a production process for a basic water-absorbent resin to be a main component of a water-absorbing agent which exhibits an excellent water absorption capacity under a load with high productivity; a production process for a water-absorbing agent; and use thereof. The production process for an irregular shape basic water-absorbent resin comprises the step of reacting a basic resin and a crosslinking agent in order to obtain the basic water-absorbent resin, with the process forwarding a crosslinking reaction and pulverizing the resultant product at the same time. The first production process for a water-absorbing agent comprises the step of blending an acidic water-absorbent resin with the basic water-absorbent resin obtained by the above-mentioned process. The second production process for a water-absorbing agent comprises the step of obtaining a mixture of an acidic water-absorbent resin and the basic water-absorbent resin by coexisting with the acidic water-absorbent resin when carrying out the crosslinking reaction and the pulverization in the above-mentioned process.

Production processes for basic water-absorbent resin and water-absorbing agent, and use thereof

The present invention provides: a process for producing a water-absorbing agent at low temperature in a short time, wherein the water-absorbing agent has excellent balance between the absorption capacity without load and the absorption capacity under a load, high fluidity under a hygroscopic atmosphere, and excellent safety; and a novel water-absorbing agent and a novel crosslinking agent particularly suitable for crosslinking water-absorbent resins. The water-absorbing agent, having excellent balance between the absorption capacity without load and the absorption capacity under a load, high fluidity under a hygroscopic atmosphere, and excellent safety, can be obtained by using an oxetane compound and/or an imidazolidinone compound for a water-absorbent resin.

Water-absorbing agent and process for producing the same

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 invention provides a hydrophilic resin and an absorbent article, both of which display still less coloring and discoloring when preserved for a long time. The hydrophilic resin is any one of: 1) a hydrophilic resin, obtained by a process including the step of polymerizing a monomer component including a major proportion of either one or both of acrylic acid and its salt which merely have a content of at most 0.20 ppm in total of hydroquinone and benzoquinone; 2) a hydrophilic resin, comprising a major proportion of an acrylic polymer and a minor proportion of either one or both of hydroquinone and benzoquinone, with the hydrophilic resin further comprising a quinhydronation inhibitor of 10&tilde;1,000,000 times the total weight of hydroquinone and benzoquinone; 3) a hydrophilic resin, comprising a major proportion of an acrylic polymer and merely having a coloring degree (YI) of at most 20 after being left under conditions of the open system, 70&deg; C., 65% RH for 1 week; and 4) a hydrophilic resin, which is a water-absorbent resin and is surface-crosslinked or surface-impregnated with a polyhydric alcohol and displays pH of 5.5 or less in a physiological salt solution and has an absorption capacity of 20 g/g or more for a physiological salt solution under a load of 50 g/cm . In addition, the absorbent article comprises the above hydrophilic resin.

Hydrophilic resin, absorbent article, and acrylic acid for polymerization

The present invention provides a process in which no surfactant is used, or even if the surfactant is used the amount thereof is as small as possible, thus stably obtaining a suspension to carry out a crosslinking reaction. A production process for a crosslinked polymer particle, comprising the steps of: forming a suspension in which liquid drops of a first phase are dispersed in a second phase by stirring both phases in the presence of an inorganic particle, wherein the first phase includes a high-molecular compound and a crosslinking agent, and wherein the first phase and the second phase are insoluble in each other, and wherein the affinity of the inorganic particle for water is different from that of the high-molecular compound; and carrying out a crosslinking reaction. Furthermore, an approximately spherical crosslinked polymer particle, which is free from a surfactant.

Crosslinked polymer particle and its production process and use

A gelling material is composed of water-absorbent resin wrapped in a bag composed of two laminated water-soluble sheets the water-absorbent resin being prepared so as to enable the bag to be disintegrated by an inner pressure generated when an expanded volume of the water-absorbent resin by absorbing water through the bag exceeds a maximum volume capacity. When the gelling material is added to the aqueous fluid, the water-absorbent resin is spread in the aqueous fluid at a stroke, and is diffused uniformly. Thus, the water-absorbent resin is brought fully in contact with the aqueous fluid. Since this enables the aqueous fluid to be gelled in a short period of time, the aqueous fluid can be processed speedily. Even the aqueous fluids, which are difficult to be handled by the conventional gelling material, can be gelled conveniently in a short period of time, and the resulting gell can be easily handled, thereby enabling an easy disposal of the aqueous fluids, i.e., the gell. Additionally, since the water-absorbent resin is spread in the aqueous fluid at a stroke, and is diffused uniformly, a troublesome operation of agitating the aqueous fluid can be eliminated during the gelling process, thereby enabling a simplified gelling process.

Water absorbent resin

The present invention provides a production process for a vinylpyrrolidone polymer which process prevents the polymerization reaction of N-vinylpyrrolidone from being hindered by by-products (as formed by nucleomethylation of N-vinylpyrrolidone) or &ggr;-butyrolactone, and therefore enables to obtain a vinylpyrrolidone polymer that has a desired molecular weight and involves only a small amount of residual monomers, wherein the vinylpyrrolidone polymer can display excellent properties even if the vinylpyrrolidone polymer is, for example, crosslinked to convert it into a water-absorbent resin. The production process for a vinylpyrrolidone polymer comprises the step of polymerizing a polymerizable monomer component or components which include N-vinylpyrrolidone, wherein: the N-vinylpyrrolidone as used is N-vinylpyrrolidone having a &ggr;-butyrolactone content of not more than 500 ppm; and/or the N-vinylpyrrolidone as used is N-vinylpyrrolidone obtained without using acetylene as a raw material.

Production process for vinylpyrrolidone polymer

The present invention has an object to provide a process for producing a water-absorbing agent which is excellent in the absorption capacities under no load and under a load with good balance and can display excellent absorption properties even if the weight percentage of a water-absorbent resin (resin concentration) is high when the water-absorbent resin is used for materials such as sanitary materials. The above object can be achieved by adding a vinyl compound or both the vinyl compound and a polyhydric alcohol to a water-absorbent resin and heating the resultant mixture.

Water-absorbing composition and production process for water-absorbing agent

Water-swellable crosslinked polymer, its composition, and their production processes and uses

The present invention has an object to provide a novel water-swellable crosslinked polymer composition which exhibits excellent saltwater absorption speed and capacity under a load. This object can be achieved in the case where, in a water-swellable crosslinked polymer composition comprising a blend of water-swellable crosslinked polymer particles of basicity in water and water-swellable crosslinked polymer particles of acidity in water, the water-swellable crosslinked polymer particles of basicity in water are unified with the water-swellable crosslinked polymer particles of acidity in water through ionic bondings in a state where water is present between the particles, wherein the ionic bondings are formed in a state where water is present between the particles by neutralization of at least part of acid groups of the water-swellable crosslinked polymer particles of acidity in water with the water-swellable crosslinked polymer particles of basicity in water.

Water-swellable crosslinked polymer composition and production

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Suita, Japan

Nobuyuki Harada