Nippon Shokubai Co., Ltd.

Katsuyuki Wada

Kunihiko Ishizaki

Hiroko Ueda

Kinya Nagasuna

Yasuhisa Nakashima

Kazuki Kimura

Hiroyuki Ikeuchi

Yoshio Irie

Motohiro Imura

Takahiro Kitano

Kozo Nogi

Takumi Hatsuda

Shinichi Fujino

Koji Miyake

Yoshifumi Adachi

Masatoshi Nakamura

Naoko Takahashi

Kazushi Torii

Yasuhiro Fujita

Yoshihiko Masuda

Shin-Ichi Fujino

Manabu Ueda

Yorimichi Dairoku

Nobuyuki Harada

Hirotama Fujimaru

Taku Iwamura

Hiroki Inoue

Hisanori Obara

Shigeru Sakamoto

Sayaka Machida

Yoshiro Mitsukami

Hirofumi Shibata

Makoto Nagasawa

Toru Inaoka

Taishi Kobayashi

Koji Honda

Takaaki Kawano

Yoshitaka Ikeuchi

Masato Abe

Yoshinori Sano

Tadao Shimomura

Toshimasa Kitayama

Sumio Okuda

Reiko Nakatsuru

Toshihiro Takaai

Kazuhisa Hitomi

Seiji Kato

Teruyuki Kanto

Hidenori Wada

Ryoko Tahara

Eri Goto

Yasuhisa Nakajima

Shin-ichi Fujino

Takuni Hatsuda

Ryuichi Hiraoka

Kazushi Horie

Kazuki; Kimura

Masatoshi Nakamuta

As a method for producing a polyacrylic acid (salt)-based water absorbent resin particle which less generates fine powder and has an excellent impact resistance and a high moisture content even in a case where the polyacrylic acid (salt)-based water absorbent resin particle is produced on a large scale, employed is a production method including the steps of: (a) adding a surface crosslinking agent solution to water absorbent resin powder to obtain a mixture; (b) reacting the mixture; and, thereafter (c) adding an aqueous liquid to at least one selected from the group consisting of (i) the water absorbent resin powder during the step (b) and (ii) the water absorbent resin powder after the step (b), an atmospheric dew point being not lower than 20&#xb0; C. in the step (c), and a temperature of the water absorbent resin powder being higher than the atmospheric dew point in the step (c).

Method for producing polyacrylic acid (salt)-based water absorbent resin

A water absorbent resin (water absorbing agent) and method for producing it are provided which improve, in a water absorbent article (in particular, a diaper) including a water absorbent resin as a water absorbing agent, the absolute absorption amount (g), liquid absorbing times (in particular, liquid absorbing times at the second instance and later), re-wet (g), and diffusion distance (%) of the water absorbent article. A particulate water absorbing agent of the present invention has a CRC, a proportion of particles with sizes of 600 &#x3bc;m to 150 &#x3bc;m as defined through a standard-sieve classification, an SST, and the value of the difference between an FST and the SST each within a predetermined range.

Particulate water absorbing agent and water absorbent article

An object of the present invention is to provide (i) a water absorbent agent composition which has an excellent additional function (a deodorizing function in particular), which stably carries out the additional function even after being stored for a long term, and which is less stressful to skin when used as an absorbent article, (ii) a method for producing the water absorbent agent composition, and (iii) an absorbent core and an absorbent article. The water absorbent agent composition contains: a polycarboxylic acid (salt)-based water absorbent resin as a main component; a natural ingredient; and a temporal deterioration preventing agent. Further, a water absorbent agent composition is produced by simultaneously or separately mixing a natural ingredient and a temporal deterioration preventing agent with a water absorbent resin which is a crosslinked polymer of unsaturated monomers having carboxylic acid and/or a salt thereof.

Water absorbent agent composition and method for producing same, as well as storage and stocking method for same

The present invention (a) provides, at low cost, a water absorbing agent (i) that has a suppressed amount of generated dust and a suppressed amount of dust that increases over time and (ii) that also has a high absorption capacity without load, a high absorption capacity under load, a high vertical diffusion absorbency under load, and a high absorbency in a short period of time, and (b) also provides a method for evaluating, in a short period of time, an amount of dust that increases over time. A particulate water absorbing agent of the present invention includes: a surface crosslinked polyacrylic acid (salt)-based water absorbent resin as a main component; a hydrophilic polymer compound; and a stabilizing agent.

Particulate water absorbing agent and process for producing same

Particulate water absorbing agent and method for manufacturing same

Provided is a process for producing a water-absorbing resin powder which contains a given amount of water added thereto, has a low dust content, and has high material properties. When a water-absorbing resin powder which has undergone surface crosslinking is produced on an industrial scale, various problems concerning production are eliminated and a long-term stable operation is possible without causing a deterioration in the material properties of the resin. Even when the process is continued over a long period, the material properties are stabilized (decrease in standard deviation) or improved (improvement in AAP). The process for producing a water-absorbing resin comprises, in the following order, a first classification step for classifying a water-absorbing resin, a surface crosslinking step after the classification, a water addition step for adding water to the water-absorbing resin powder after or during the surface crosslinking, a second classification step, and a conveying step.

Process for producing water-absorbing resin powder

A water-absorbent resin composition suffering exfoliation of additives from a water-absorbent resin only insignificantly and excelling in fluidity of powder after absorption of moisture and in deodorizing property and absorbent property as well is provided. The water-absorbent resin composition of this invention comprises a water-absorbent resin obtainable by polymerizing an unsaturated monomer having an acid group and/or a salt thereof; and complex oxide hydrate containing zinc and silicon, or zinc and aluminum, wherein the complex oxide hydrate contains zinc as main metal component, the mass ratio of the content of zinc and the content of silicon or aluminum is in the range of 50/50-99/1, and the absorption capacity at 60 minutes toward 0.90 mass % sodium chloride aqueous solution under the pressure of 1.9 kPa is not less than 20 g/g. Optionally, a plant component (C) can be added to the water absorbent resin composition.

Water-absorbent resin composition and method for producing thereof, and absorbent material and absorbent product using thereof

A particulate water absorbing agent of the present invention is a water absorbing agent containing a water absorbing resin as a main component, the particulate water absorbing agent containing a polyvalent metal cation and satisfying: (1) the polyvalent metal cation is contained in an amount between 0.001 wt % and 5 wt % relative to the amount of the water absorbing agent; (2) an absorbency without pressure (CRC) is not less than 28 (g/g) and an absorbency against pressure (AAP 4.83 kPa) is not less than 10 (g/g); (3) the absorbency against pressure and the absorbency without pressure satisfy 77 &#x2266;AAP (4.83 kPa)+1.8&#xd7;CRC&#x2266;100; and (4) a moisture content of the water absorbing agent is between 5 wt % and 20 wt %. This provides a water absorbing agent which has blocking resistance after moisture absorption, is excellent in stability to shock and suppresses Re-Wet when used in a diaper.

Particulate water absorbent and process for production thereof

A particulate water-absorbing agent containing a surface-crosslinked polyacrylic acid (salt)-type water-absorbing resin as a main component and at least one spacer selected from a polycation and water-insoluble fine particles. The particulate water-absorbing agent has a free swell capacity (FSC) of 55 to 65 g/g, an absorption against pressure (AAP&#x2014;4.83 kPa) of 20 to 30 g/g, and a vertical diffusion absorption amount under pressure (VDAUP&#x2014;4.83 kPa) of 30 to 80 g. Also disclosed is a method for producing a particulate water-absorbing agent, an absorbent core containing the particulate water-absorbing agent, and an absorbing article containing the absorbent core.

Particulate water-absorbing agent and production method for the same

To improve the heat retention by diapers and other absorbents, a heat retention indicator 1 of a water-absorbing resin which is defined in the present invention needs be 3.0&#xb0; C./min or less and also that particular requirements need be met to satisfy this condition. If the requirements are met, a water-absorbing resin, absorbent, and absorbent article can be provided which has a heat retention indicator 1 of 0 to 3.0&#xb0; C./min or less and which exhibits excellent heat retention and absorption.

Water-absorbing agent, manufacture method thereof, and absorbent and absorbent article made therefrom

A water absorbing agent of the present invention has an internal crosslinking structure obtained by polymerization of a water-soluble unsaturated monomer. The agent satisfies conditions (a) to (d): (a) the agent contains water-insoluble inorganic particles at an amount of from 10 ppm to 1,900 ppm inclusive; (b) the agent contains 5 mass % or less particles which have such a size that they can pass through a sieve having a mesh opening size of 150 &#x3bc;m; (c) the agent has an absorbency against a pressure of 4.83 kPa (AAP) of 18 g/g or more; and (d) the water-insoluble inorganic particles reside on a surface of the water absorbing resin or near the surface.

Water absorbing agent, water absorbent core using the agent, and manufacturing method for water absorbing agent

Disclosed is a method for producing a water absorbent resin, by which a surface-crosslinked water absorbent resin having excellent physical properties can be efficiently obtained at low cost, while assuring high productivity. When the production scale is increased to a continuous production on a huge scale (for example, 1 t/hr or more), the physical properties are improved and stabilized (for example, standard deviation of the physical properties is reduced) by a surface-crosslinking treatment, and the absorption against pressure (AAP) and liquid permeability (SFC) are further improved. Specifically disclosed is a method for continuously producing a polyacrylic acid (salt)-type water absorbent resin powder, which comprises: a step of preparing an aqueous monomer solution using an acrylic acid (salt); a step of polymerizing the aqueous monomer solution; a shredding step of a hydrous gel-like crosslinked polymer during or after the polymerization; a step of drying the thus-obtained particulate hydrous gel-like crosslinked polymer; a step of crushing and classifying the dried product; a step of heating and surface-crosslinking after the classification; and a step of cooling after the surface-crosslinking. In the method for producing a polyacrylic acid (salt)-type water absorbent resin, the internal area of the cooling device that is used in the cooling step is 0.25-0.95 times the internal area of the heating device that is used in the surface-crosslinking step.

Polyacrylic acid (salt)-type water absorbent resin and method for producing of same

A water absorbing agent includes water absorbent resin particles which are obtained by polymerizing a water-soluble ethylenic unsaturated monomer and which internally include a cross-linked structure, wherein a pressurized void average radius index is 140 or more. As a result, it is possible to provide a water absorbing agent which essentially includes water absorbent resin particles and is suitable for use in a sanitary material. Specifically, it is possible to improve not only a performance for absorbing and retaining aqueous liquid without pressure or under pressure but also (i) a performance for quickly absorbing aqueous liquid with a great help of a performance of a fibrous material, (ii) a performance for dispersing the aqueous liquid after absorbing the aqueous liquid, and (iii) a performance for retaining the aqueous liquid after absorbing the aqueous liquid.

Water absorbing agent and production method thereof

Provided is a water absorbent resin having excellent liquid permeability, water absorbent speed, anti-impact stability, and weather resistance. Provided is a polyacrylic acid (salt)-based water absorbent resin powder in which the water absorption capacity without load (CRC) is 30 to 45 [g/g], the water absorption capacity under load (AAP 0.3) is 20 to 35 [g/g], the water absorption capacity under load (AAP 0.7) is 10 to 28 [g/g], and the weight average particle diameter (D50) is 300 to 500 &#x3bc;m, characterized by including p-methoxyphenol; having a degradable soluble component (0.05% L-A (saline) for 2 hours/60&#xb0; C., one hour extraction rinse/room temperature) of 40% by weight or less; and having a internal gas bubbles ratio of 0.1 to 2.5%, as specified by the following equation.(Internal gas bubbles ratio)[%]={(True density)&#x2212;(Apparent density)}/(True density)&#xd7;100

Polyacrylic acid (salt)-based water absorbent resin powder and method for producing the same

A particulate water absorbing agent of the present invention is a water absorbing agent containing a water absorbing resin as a main component, the particulate water absorbing agent containing a polyvalent metal cation and satisfying: (1) the polyvalent metal cation is contained in an amount between 0.001 wt % and 5 wt % relative to the amount of the water absorbing agent; (2) an absorbency without pressure (CRC) is not less than 28 (g/g) and an absorbency against pressure (AAP 4.83 kPa) is not less than 10 (g/g); (3) the absorbency against pressure and the absorbency without pressure satisfy 77&#x2266;AAP (4.83 kPa)+1.8&#xd7;CRC&#x2266;100; and (4) a moisture content of the water absorbing agent is between 5 wt % and 20 wt %. This provides a water absorbing agent which has blocking resistance after moisture absorption, is excellent in stability to shock and suppresses Re-Wet when used in a diaper.

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Himeji, Japan

Katsuyuki Wada