Nippon Shokubai Co., Ltd.

Kazuki Kimura

Katsuyuki Wada

Kunihiko Ishizaki

Takumi Hatsuda

Kazushi Torii

Yusuke Watanabe

Masatoshi Nakamura

Hirofumi Shibata

Reiko Nakatsuru

Koji Miyake

Kenji Kadonaga

Yasuhiro Fujita

Sayaka Machida

Hiroko Ueda

Kenji Tada

Toru Yanase

Daisuke Takeda

Yoshio Irie

Kozo Nogi

Nobuyuki Harada

Shigeru Sakamoto

Shinichi Fujino

Yorimichi Dairoku

Kinya Nagasuna

Hiroyuki Ikeuchi

Motohiro Imura

Yasuhisa Nakashima

Shin-Ichi Fujino

Nobuya Tanaka

Taku Fujimoto

Satoshi Matsumoto

Hirotama Fujimaru

Taku Iwamura

Hideyuki Tahara

Takahiro Kitano

Yoshihiro Motono

Koji Honda

Teruyuki Kanto

Akito Yano

Hidenori Wada

Tomoya Arai

Eri Goto

Yuki Tanaka

Kazushi Horie

Kimiaki Nishimura

Shin-ichi Fujino

Yudai Fujii

Koji Shibata

Masatoshi Nakamuta

Provided are: a water-absorbing agent achieving, in a balanced manner, both good physical properties and a decrease in speed of coloration with lapse of time even if the water-absorbing agent has a high moisture absorbing speed due to having a large specific surface area; and an absorbent body having a low ratio of pulp and achieving, in a balanced manner, both good physical properties suitable for a thin disposable diaper and a decrease in speed of coloration with lapse of time. The absorbent body contains a hydrophilic base material and a water-absorbing agent which contains: surface-crosslinked water-absorbing resin particles having a non-uniformly pulverized shape; α-hydroxycarboxylic acid (salt); and an aminocarboxylic acid-based chelating agent and/or a phosphorus-based chelating agent, a point plotted along an x-axis that represents an amount (xmol %) of α-hydroxycarboxylic acid (salt) extracted from the water-absorbing agent and along a y-axis that represents an amount (ymmol %) of an aminocarboxylic acid-based chelating agent and/or a phosphorus-based chelating agent extracted from the water-absorbing agent being within a range that satisfies a specific relational formula of xand y, the water-absorbing agent having a moisture absorbing speed of 120 mg/g/hr or more at a temperature of 40±1° C. at a relative humidity of 75±1% RH.

Absorbent material, water absorbent and method for producing water absorbent

It is an object to provide a water-absorbing resin that while maintaining water-absorbing resin physical properties such as water absorption performance, has a sufficiently reduced odor produced during swelling. The object is attained by causing the water-absorbing resin to be a water-absorbing resin which is a surface-crosslinked water-absorbing resin, the water-absorbing resin having a volatile component concentration of 3.5 ppm or less as measured when the water-absorbing resin is caused to stand still for 15 minutes under a condition that the water-absorbing resin has a swelling capacity of 1.0-fold.

Water-absorbing resin and manufacturing method for same

The present invention provides an easy method for producing a water absorbent agent that has a low moisture content and that has a small dust generation amount without decreasing various physical properties. A present inventive method for producing a water absorbent agent of the present invention includes mixing not lower than 0.06 parts by mass and not higher than 5 parts by mass of an inorganic acid alkali metal salt powder with 100 parts by mass of a water-absorbent resin in an indefinite ground form.

Water absorbent agent and method for producing water absorbent agent

The present invention provides a water absorbent agent that achieves both improvement in the water absorption time thereof and reduction in the residual monomer variation rate thereof. A present inventive method for producing a water absorbent agent having a water-absorbent resin as a main component, the method including a surface-crosslinking step for a water-absorbent resin and a mixing step for a sulfur-containing reducing agent aqueous solution, the method satisfies (1) a specific surface area of the water-absorbent resin, (2) an average droplet diameter of the sulfur-containing reducing agent aqueous solution, and a temperature of the aqueous solution, (3) stirring-mixing conditions, and (4) a heating and drying step conditions.

Water absorbent agent having water-absorbent resin as main component and comprising a sulfur-containing reducing agent

Provided is a water-absorbing agent having an excellent ability to absorb and retain liquid and an excellent liquid suction power. The water-absorbing agent contains a polyacrylic acid (salt)-based water-absorbing resin as a main component and satisfies all of the following physical properties (a) to (e): (a) a weight average particle diameter (D50) is 300 &#x3bc;m or more and less than 400 &#x3bc;m; (b) a proportion of particles with a particle diameter of 600 &#x3bc;m or more and less than 850 &#x3bc;m is less than 10 weight %; (c) an average gap radius is 100 &#x3bc;m or more and less than 180 &#x3bc;m; (d) a CRC is 28 g/g or more and less than 34 g/g; and (e) an AAP is 24 g/g or more.

Water-absorbing agent and method for producing same, and absorbent article produced using water-absorbing agent

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 maintains a certain degree of liquid permeability and water absorption speed while also reducing re-wet in a disposable diaper, without the use of costly raw materials or costly apparatuses. The water-absorbing agent of the present invention contains a polyacrylic acid salt-based water-absorbing resin as a main component and has physical properties falling within a specific range, the physical properties being saline flow conductivity (SFC), gap fluid retention property under pressure, and a proportion of particles having a particle diameter of not less than 150 &#x3bc;m and less than 710 &#x3bc;m.

Water absorbent agent

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 present invention relates to an absorbent suitable for use in a thin sanitary material/absorbent article having a high absorbent content and not prone to gel blocking, the absorbent having excellent liquid diffusibility (e.g. SFC) and minimal decrease in absorption ratio under pressure (e.g., AAP or PUP) even when a liquid permeation enhancer is added, and to a method for manufacturing the high-performance absorbent stably during actual production. The method is a method for manufacturing a polyacrylic acid (salt)-based absorbent, having a surface-crosslinking agent addition step for adding a solution of a surface-crosslinking agent, and a liquid permeation enhancer addition step for adding a liquid permeation enhancer, the liquid permeation enhancer addition step being performed after and/or at the same time as the surface-crosslinking agent addition step, the method characterized in that a surface crosslinking step for performing heat treatment in an atmosphere having a dew point of 45&#xb0; C. to 100&#xb0; C. is performed after or at the same time as the surface-crosslinking agent addition step.

Method for producing polyacrylic acid (salt)-based water absorbing agent, and water absorbing agent

From a view point of reduction in an out of spec product after surface crosslinking, particularly, when an alkylene carbonate compound is used as a surface crosslinking agent, influence by an air temperature is great, and it is necessary to reduce ethylene glycol which is produced as a byproduct, and there is provided a process for producing a polyacrylic acid (salt)-based water absorbent resin powder, comprising

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

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

Objects of the present invention are: to provide a water-absorbent resin which exhibits excellent balances between water absorption performances; and further to provide a process by which a water-absorbent resin having excellent absorption properties can be produced even if no hydrophilic organic solvent is used, or even if its amount is extremely reduced, when carrying out the surface-crosslinking treatment; and further to provide a water-absorbent resin optimum to absorbent articles such as diapers. As a means of achieving these objects, the process according to the present invention for production of the water-absorbent resin comprises: a step (1) of polymerizing a monomer component including an acid-group-containing unsaturated monomer as an essential component to thereby obtain a hydrogel polymer; a step (2) of drying and pulverizing the hydrogel polymer to thereby obtain a water-absorbent resin powder; a step (3) of adding a surface-crosslink-treating agent to the water-absorbent resin powder, wherein the surface-crosslink-treating agent includes a surface-crosslinking agent and water as essential components and has a hydrophilic organic solvent content of 0 to 10 mass % relative to the surface-crosslink-treating agent; and a step (4) of heating the resultant mixture to thereby carry out surface-crosslinking treatment; wherein a time of from the end of the step (3) till the beginning of the step (4) is within 5 minutes.

Water-absorbent resin and its production process

An object of the present invention is to provide a water absorbing agent having a low amount of residual monomer, small variance of the amount of residual monomer among ranges of particle size distribution and favorable absorption properties, and being sanitary; an absorbing article; and a method for the production of a water absorbing agent. The water absorbing agent of the present invention has the amount of residual monomer of not higher than 500 ppm, and a residual monomer index of not greater than 0.30. The method for the production includes a first step of obtaining a hydrogel polymer by polymerizing an aqueous solution of a monomer including an unsaturated carboxylic acid and/or a salt thereof in the presence of a crosslinking agent; a second step of obtaining a water absorbent resin precursor which is in powder form and includes particles having a particle size of 300 to 850 &#x3bc;m and particles having a particle size of smaller than 300 &#x3bc;m as main components by drying said hydrogel polymer followed by pulverization and classification to adjust the particle size distribution, a third step of obtaining a water absorbent resin by heating a mixture of said water absorbent resin precursor and a surface crosslinking agent, which can form an ester bond around the surface of said water absorbent resin precursor, a fourth step of adding by spraying an aqueous solution that includes a sulfur-containing reducing agent to said water absorbent resin, and a fifth step of subjecting the mixture of the water absorbent resin and said aqueous solution to a heat treatment under an airflow of not lower than 40&#xb0; C. but not higher than 120&#xb0; C.

Particulate water absorbing agent comprising crosslinked absorbent resin and having low residual monomer, water absorbing article and method for production of water absorbing agent

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Himeji, Japan

Kazuki Kimura