Nippon Shokubai Co., Ltd.

The Procter Gamble Company

Kazushi Torii

Hiroyuki Ikeuchi

Shigeru Sakamoto

Taku Iwamura

Sayaka Machida

Yusuke Watanabe

Toshimasa Kitayama

Kenji Tada

Hirofumi Shibata

Yoshifumi Adachi

Kunihiko Ishizaki

Kazuki Kimura

Yoshiro Mitsukami

Motohiro Imura

Katsuyuki Wada

Yasuhisa Nakashima

Kozo Nogi

Nobuyuki Harada

Yoshio Irie

Kazuhiko Sakamoto

Yorimichi Dairoku

Shinichi Fujino

Koji Miyake

Kenji Kadonaga

Hiroko Ueda

Mattias Schmidt

Holger Beruda

Makoto Matsumoto

Satoshi Matsumoto

Hirotama Fujimaru

Atsuro Yoneda

Masatoshi Nakamura

Seiichi Suzuki

Hiroki Inoue

Shin-Ichi Fujino

Taishi Kobayashi

Nobuya Tanaka

Kohei Omori

Reiko Nakatsuru

Koji Tachi

Hironori Sato

Yoko Shirai

Hiroki Kawada

Takahiro Kitano

Daisuke Takagi

Taku Fujimoto

Mariko Tamaki

Yasuhisa Nakajima

Makoto Nagasawa

Ryota Wakabayashi

Toshihiro Takaai

Kazuhisa Hitomi

Yasue Nakagawa

Hidenori Wada

Hiroko Okochi

Yukihiro Kasano

Ryoko Tahara

Tatsushi Hirauchi

Yuika Noda

Hiroyuki Goto

Ryosuke Fujikawa

Shin-ichi Fujino

Kunihiki Ishizaki

Yuichiro Horimoto

Makiko Masuda

Ryuichi Hiraoka

Mai Wada

Kazushi Horie

Provided are a water-absorbing resin having more excellent balance of fluid retention capacity, liquid permeability, and low dustiness and a novel measurement method which enables evaluation of excellent physical properties of the water-absorbing resin. A method for measuring an absorption speed of a particulate water-absorbing agent is a method including the step of applying pressure to a portion of a bottom surface of a measurement container () by use of a flat plate () in a state in which part or whole of the particulate water-absorbing agent () is fixed on the bottom surface of the measurement container (), the bottom surface being surrounded by a frame, introducing an aqueous solution through a liquid injection inlet () with which the flat plate () is equipped, and then measuring the amount of time elapsed until an end of absorption of the introduced aqueous solution by the particulate water-absorbing agent ().

Measurement method for properties of particulate absorbent agent, and particulate absorbent agent

Provided is a water-absorbing agent that causes no or little fluctuation of feed rate when fed with use of a feeder. A water-absorbing agent containing a water-absorbing resin as a main component, the water-absorbing agent satisfying the following (a) and (b): (a) K-index is 70 or more; and (b) Moisture absorption blocking ratio, after 30 minutes of standing at a temperature of 25&#xb0; C. and a relative humidity of 80% RH, is 70 weight % or less, the K-index being defined by the following equation: K-index=100&#x2212;(&#x2212;438+3.6&#xd7;angle of repose+3.5&#xd7;angle of difference+7.9&#xd7;compressibility rate+290&#xd7;bulk density (EDANA method)).

Absorption agent and absorbent article

A water absorbent agent having a high water absorption multiplying factor where stickiness after absorbing liquid can be reduced when used as a hygienic material is produce by a method for manufacturing the water absorbing agent. The method for manufacturing a water absorbent agent having a centrifuge retention capacity (CRC) of 30 g/g or greater, includes subjecting an aqueous solution of a monomer that includes an acrylic acid (salt) to a polymerization step, a drying step, and a surface cross-linking step, and a step for adding &#x3b1;-hydroxycarboxylic acid (salt) before the drying step. The atomic weight of the soluble portion eluted when the water absorbent agent absorbs liquid and swells can be reduced by the &#x3b1;-hydroxycarboxylic acid (salt) before the drying step to reduce the stickiness of the water absorbent agent after absorption of liquid, which leads to discomfort during use of disposable diapers and the like.

Method for manufacturing water absorbing agent

The present invention provides polyacrylic acid (salt)-based water-absorbing resin powder having an excellent fluid retention capacity under pressure, an excellent water absorption speed, and an excellent liquid permeability and a method for producing the polyacrylic acid (salt)-based water-absorbing resin powder. The earlier-described objects are attained by: a method for producing water-absorbing resin powder which includes adding an inorganic compound to a crosslinked hydrogel polymer obtained in a polymerization step of polymerizing a polyacrylic acid (salt) and performing crushing in specific gel-crushing conditions; and the resultant water-absorbing resin powder.

Super absorbent polyacrylic acid (salt)-based resin powder, method for manufacturing same, and method for evaluating same

To provide a water-absorbing resin composition having both a high centrifuge retention capacity (CRC) and a sufficient urine resistance and a method for producing such a water-absorbing resin composition, an aspect of the present invention is a water-absorbing resin composition having the following properties: (1) A centrifuge retention capacity (CRC) being not less than 35 g/g; (2) A post-degradation-test one-hour eluted soluble component being not more than 19% by mass; (3) An absorbency against pressure 0.7 psi (AAP0.7) being not less than 10 g/g; and (4) A content of a water-absorbing resin in dust being not more than 300 ppm with respect to a total mass of the water-absorbing resin composition.

Water-absorbing resin composition

A method for filling a particulate water absorbing agent includes a filling step of filling a particulate water absorbing agent into a filling container and a vibrating step of vibrating the filling container at the outside of the filling container, the vibrating step being conducted at least one time between the start and the end of the filling step, in which a vibration condition in the vibrating step satisfies the following conditions (a) and (b):(a) vibration by a vibrating body in contact with the filling container has a vertical directional component and a vibrational angle is within 90&#xb0;&#xb1;30&#xb0;; and (b) total amplitude at no load and a vibration frequency at no load of the vibrating body are set so as to satisfy Equation 1-1 and Equation 2 or Equation 1-2 and Equation 2.

Method for filling particulate water absorbing agent and method for sampling filled particulate water absorbing agent

Provided is a water-absorbing agent which is less likely to cause gel blocking and is suitable for a sanitary product and an absorbent article each being thin and containing a large amount of a water-absorbing agent, and which, while maintaining or hardly losing the other physical properties (a fluid retention capacity and a bulk specific gravity) of the water-absorbing agent, simultaneously achieves a high water absorbing speed (e.g., FSR), a high fluid retention capacity under load, high liquid permeability, and salt tolerance. The water-absorbing agent is a polyacrylic acid (salt)-based water-absorbing agent whose surface and its vicinity are crosslinked by an organic surface crosslinking agent, characterized by satisfying the following (A)-(D): (A) Free Swell Rate (FSR) of at least 0.28 g/g/s, or Absorption Time (Vortex) of 42 seconds or less; (B) Absorption Against Pressure (AAP) of at least 20 g/g; (C) Salt Tolerance Index represented by 'Salt Tolerance Index=(CRCdw)/(CRCs)' where CRCdw is a centrifuge retention capacity (unit; g/g) for deionized water (dw), and CRCs is a centrifuge retention capacity (unit; g/g) for a 0.9 weight % saline, satisfying 'Salt Tolerance Index&#x2264;0.49&#xd7;CRCs&#x2212;7.47'; and (D) Bulk Specific Gravity of 0.55 to 0.70 g/cm.

Polyacrylic acid (salt) water absorbent, and method for producing same

Provided is a water absorbent resin that is useful to sanitary materials such as a disposable diaper, a sanitary napkin, and a blood absorbent for medical use each having a higher liquid permeability and a higher water absorbing speed. Further provided is a water absorbent resin powder that is useful to sanitary materials such as a disposable diaper, a sanitary napkin, and a blood absorbent for medical use each having increased in absorbency of a liquid and in heat retaining property. A gel grinding device to be used to produce a water absorbent resin, includes: a screw; a feed opening; an extrusion opening; a porous plate; and a barrel, the barrel including a return preventing member provided on an inner surface thereof, and the return preventing member satisfying at least one of specific parameters.

Water absorbent resin powder

An object of the invention is to provide a technique in which a decrease in physical properties is suppressed or consumer complaints are diminished. A method includes a filling step of filling a particulate water absorbing agent into a filling container and a vibrating step of vibrating the filling container at the outside of the filling container, the vibrating step being conducted at least one time between the start and the end of the filling step. A vibration condition in the vibrating step satisfies the following conditions: (a) vibration by a vibrating body in contact with the filling container has a vertical directional component and a vibrational angle is within 90&#xb0;&#xb1;30&#xb0;; and (b) total amplitude at no load and a vibration frequency at no load of the vibrating body are set so as to satisfy Equation 1-1 and Equation 2 or Equation 1-2 and Equation 2.

The purpose of the present invention is to provide a particulate water absorbing agent having both a high water absorption multiplying factor and a high water absorption rate and a method for manufacturing the same. The present invention is a particulate water absorbing agent for which CRC is 30 to 50 g/g, wherein the weight average particulate diameter (D50) is 200-600 &#x3bc;m, and the DRC index given by the following formula is a specific value (for example, 43, 30, or 20) or less: DRC index=(49&#x2212;DRC5min [g/g])/(D50 [&#x3bc;m]/1000).

Particulate water absorbing agent

Provided is a method for producing a particulate water absorbing agent, the method including the steps of: a polymerization step of polymerizing an acrylic acid (salt)-based aqueous monomer solution so as to obtain a crosslinked hydrogel polymer; a drying step of drying the crosslinked hydrogel polymer so as to obtain a dried polymer; a classification step of classifying a polymer subjected to classification so as to obtain a water-absorbing resin powder having a specific particle size; and a surface-crosslinking step of surface-crosslinking the water-absorbing resin powder that is not surface crosslinked, wherein the classification step is carried out at least either or both of before and/or after the surface-crosslinking step but after said drying step, and wherein a hole shape of a classification sieve used in the classification step is an irregular polygonal or non-circular.

Method for producing particulate water-absorbing agent

A particulate water absorbing agent having a polyacrylic acid (salt)-based water-absorbing resin as a main component, being surface-crosslinked and satisfying physical properties (1) to (3) below: (1) a proportion of particles with a particle diameter of not less than 150 &#x3bc;m and less than 850 &#x3bc;m is not less than 90% by weight; (2) an elastic modulus index (EMI) of particles with a particle diameter of not less than 500 &#x3bc;m and less than 600 &#x3bc;m is not less than 5500; and (3) a recovery rate defined as Rec.CRC/CRC is 1.05 to 1.20, the particulate water absorbing agent being particularly useful for absorbent articles.

An object of the present invention is to provide a method for producing water absorbent resin powder in which permeability potential (SFC) is improved while a water absorbing rate (FSR) is being kept. The method is a method for producing water absorbent polyacrylic acid (salt) resin powder including the steps of: (i) polymerizing an acrylic acid (salt) monomer aqueous solution; (ii) during or after the step of (i), performing gel grinding of a hydrogel crosslinked polymer obtained by the polymerization, wherein the hydrogel crosslinked polymer has resin solid content of 10 wt % to 80 wt %, and the gel grinding is carried out with gel grinding energy (GGE) of 18 [J/g] to 60 [J/g]; (iii) drying a particulate hydrogel crosslinked polymer obtained by the gel grinding, wherein the drying is performed at 150&#xb0; C. to 250&#xb0; C.; and (iv) carrying out a surface treatment to the particulate hydrogel crosslinked polymer thus dried.

Method for producing water absorbent polyacrylic acid (salt) resin powder, and water absorbent polyacrylic acid (salt) resin powder

Gel pulverization device, method for manufacturing polyacrylic acid (polyacrylate) superabsorbent polymer powder, and superabsorbent polymer powder

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Himeji, Japan

Kazushi Torii