Nippon Shokubai Co., Ltd.

The Procter Gamble Company

Yoshiro Mitsukami

Taku Iwamura

Kazushi Torii

Torsten Lindner

Kozo Nogi

Yorimichi Dairoku

Makoto Matsumoto

Andreas Flohr

Motohiro Imura

Yoshio Irie

Sayaka Machida

Kunihiko Ishizaki

Katsuyuki Wada

Hiroko Ueda

Hirofumi Shibata

Koji Matsumoto

Taishi Kobayashi

Koji Honda

Taku Fujimoto

Erina Minami

Masato Abe

Esther Oliveros

Kazuyuki Oshima

Shigeru Sakamoto

Hiroyuki Ikeuchi

Koji Miyake

Peter Dziezok

Kenji Kadonaga

Masatoshi Nakamura

Arsen Arsenov Simonyan

Hiroki Inoue

Toshimasa Kitayama

Shin-Ichi Fujino

Reiko Nakatsuru

Nobuya Tanaka

Marion Lutsche

Syuji Kanzaki

Heike Opper

Gabriela Schaefer

Carolin Michaela Borgmann

Keisuke Kikuchi

Provided is a method for producing an absorbent article comprising a water-absorbing resin having an excellent initial water absorption speed under load even substantially without adding a liquid permeability enhancer. The method steps for producing the water-absorbing resin includes the step of polymerizing a monomer while adding certain polyalkylene glycol thereto so as to generate, during or after the polymerization, a crosslinked hydrogel polymer containing the polyalkylene glycol of a specific molecular weight, wherein the crosslinked hydrogel polymer has a centrifuge retention capacity within a given range and a final water-absorbing resin to be obtained has various physical properties (CRC, AAP, SFC, FSR) being within given ranges.

Method for producing absorbent articles comprising water-absorbing resin

A water-absorbing resin having a high swollen gel elastic modulus, a high swelling capacity and a method for producing the same are provided where the water-absorbing resin includes a water soluble unsaturated monomer having a dissociable group, an internal crosslinked structure index expressed by the following numerical formula of 14 or more, a weight average molecular weight (Mw) after a hydrolysis treatment of 220,000 or less, and a molecular weight distribution (Mw/Mn) after a hydrolysis treatment of 3.40 or less: Crosslinked structure index=(Equilibrium swelling capacity with respect to 0.9 wt % physiological saline solution/(Weight average molecular weight (Mw) after hydrolysis treatment)&#xd7;1000000; where the hydrolysis treatment leaves 50 mg of the water-absorbing resin as a solids content to stand still in 10 g of a 0.1 mol/l aqueous sodium hydroxide solution for 3 weeks at 80&#xb0; C., and the weight average molecular weight (Mw) is measured after the treatment.

Absorbent resin and method for producing the same

Absorbing articles comprises water absorbing resin including a water-soluble unsaturated monomer, having a dissociable group, as a main component in a repeating unit of a main chain and an internal cross-linked structure, in which a cross-linked structure index represented by the formula [Cross-linked structure index=(Equilibrium swelling capacity with respect to 0.9% by weight of brine)/(Weight average molecular weight after hydrolysis treatment)&#xd7;1,000,000] is 14 or more, a weight average molecular weight after hydrolysis treatment is 220,000 or less, and a molecular weight distribution after hydrolysis treatment is 3.40 or less, and a method for producing the same.

Absorbing articles comprising water absorbing resin and method for producing the same

The present invention provides (i) a water absorbing agent which is excellent in a water absorbing physical properties, in particular water absorbing speed and has a great bulk specific gravity and (ii) a method for producing the water absorbing agent. The method for producing the water absorbing agent includes a surfactant adding step of adding a surfactant whose HLB is 10 or less. The surfactant adding step is the step of adding a dispersion liquid, which contains the surfactant equivalent to 30 parts by weight to 150 parts by weight, relative to 1000000 parts by weight of a water absorbent resin solid content, and the surfactant adding step is carried out after a drying step. Further, in a case where a water-soluble polyvalent metal salt adding step is carried out after the drying step, the surfactant adding step is carried out after the water-soluble polyvalent metal salt adding step.

Water absorbing agent 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.

Particulate water absorbent and process for production thereof

Provided is a surface treatment method for a water-absorbent resin having excellent production efficiency, absorption capacity against pressure, fluid permeability or the like. Provided is a method for the surface treatment of a water-absorbent resin which comprises a) a step for mixing 0.1 to 20 parts by weight of an acid group-containing radically polymerizable compound and 5 to 20 parts by weight of water, relative to 100 parts by weight of a water-absorbent resin; and b) a step for polymerizing the acid group-containing radically polymerizable compound, wherein neutralization ratio of the acid group-containing radically polymerizable compound is 0 to 60% by mol, and is lower than neutralization ratio of the water-absorbent resin.

Surface treatment method for water-absorbent resin

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.

An object of the present invention is to provide a water absorbent having excellent gel properties and showing excellent properties when used in a water-absorbing material of a sanitary/hygienic material such as paper diaper. Moreover, another object of the present invention is to provide a water absorbent which is safe and excellent in liquid permeability, and in which an amount of liquid permeability improver for improving the liquid permeability is reduced. The water absorbent is made from a water-absorbing resin prepared by a specific polymerization method and having a high degree of cross-linking, a high liquid holding property and a high gel strength (its swelling pressure of gel layer of is 35 kdyne/cm2 or more). This water absorbent is further processed to have a particular particle size distribution (95 wt % or more of its particles are less than 850&fnof;&#xca;m but not less than 106&fnof;&#xca;m, and logarithmic standard deviation (&fnof;&Dstrok;&fnof;&#xc4;) is in a range of 0.25 to 0.45) and then surface cross-linked. After that, a liquid permeability improver is added therein.

Water absorbent and producing method of same

A method for the production of a water-absorbing resin is to be provided which permits enhancement and stabilization of property, for example, liquid permeability, of a water-absorbing resin by a simple and convenient method without requiring change of raw materials or expensive facility investment. The method comprises a polymerization step for polymerizing an aqueous solution of acrylic acid (or salt thereof) to obtain a hydrogel cross-linked polymer; a drying step for drying the hydrogel cross-linked polymer to obtain a water-absorbing resin powder; a classification step for classifying the water-absorbing resin powder; and a surface cross-linking step for surface cross-linking the water-absorbing resin powder before or after the classification step, wherein electricity is eliminated in the classification step.

Production method and method for enhancing liquid permeability of water-absorbing resin

[PROBLEM] To obtain a particulate water absorbent having excellent and stabilized physical properties. [SOLUTION] One example of the production method for particulate water-absorbing agent of the present invention includes a polymerization step for polymerizing a monomer to obtain a polymer gel, a drying step for drying the polymer gel to obtain a particulate water-absorbing resin, a pulverization step for pulverizing the particulate water-absorbing resin, a classification step for sieving the particulate water-absorbing resin, a surface cross-linking step for cross-linking the neighborhood of the surface of the particulate water-absorbing resin to obtain the particulate water-absorbing agent, a packaging step for filling the particulate water-absorbing agent into a packaging material container for packaging, and a transportation step for transporting the products produced in each of the steps to the other steps, wherein at least any one of the steps including and subsequent to the drying step is in two or more lines, for one line of the polymerization step.

Method for production of particulate water absorbent comprising water-absorbable resin as main ingredient

There are disclosed a water-absorbent resin composition and its production process, wherein the water-absorbent resin composition causes little gel-blocking and is excellent in the liquid permeability and liquid diffusibility and is high also in the absorption performances and further is strong also against the physical damage; and there are further disclosed a water-absorbent resin composition and its production process, wherein the water-absorbent resin composition has the following further advantages, in addition to the above, of involving little segregation of the metal compound and further having a dust prevention effect. One of water-absorbent resin compositions according to the present invention is a water-absorbent resin composition comprising water-absorbent resin particles obtained by polymerizing a monomer including acrylic acid and/or its salt, with the composition having a mass-average particle diameter of 100 to 600 &#x3bc;m and comprising water-soluble polyvalent metal salt particles and the water-absorbent resin particles that have been surface-crosslinked.

Water-absorbent resin composition and its production process

This invention is to provide a method for surface-treatment of a water absorbent resin excelling in water absorption properties. This invention relates to a method for the surface-treatment of a water absorbent resin, which comprises: a) mixing 100 parts by weight of a water absorbent resin, 0.01-20 parts by weight of at least one radical polymerization initiator selected from the group consisting of persulfates, hydrogen peroxide, and azo compounds, and a radically polymerizing compound and b) irradiating the resultant mixture with active energy rays. The treatment particularly exalts the absorption ratio against pressure and the saline flow conductivity.

Method for surface-treatment of water absorbent resin

An absorbent member and a method for making such an absorbent member. The absorbent member includes a modified water absorbent resin having good production efficiency, absorbency against pressure, absorption speed, gel strength, and liquid permeability. The modified water absorbent resin may be made by mixing a water absorbent resin, water, and a water-soluble radical polymerization initiator without addition of an ethylenically unsaturated monomer to obtain a water absorbent resin composition, and irradiating the water absorbent resin composition with active energy rays. During irradiation, the surface water content of the water absorbent resin is at least 3.0 wt %.

Absorbent article comprising a modified water absorbent resin

The present invention relates to a method of surface cross-linking superabsorbent polymer particles using UV irradiation. The superabsorbent polymer particles for use in the method of the present invention have a relatively high degree of neutralization. Bronsted acids are selectively applied onto the surface of the superabsorbent polymer particles to selectively facilitate a relatively high number of protonated carboxyl groups at the surface of the superabsorbent polymer particles while the relatively high degree of neutralization in the core of the superabsorbent polymer particles remains substantially unaffected.

Method of surface cross-linking superabsorbent polymer particles using ultraviolet radiation and bronsted acids

The subject invention provides a hydrophilic polymer (water-absorbing resin) which is superior in performance and productivity. According to the production method of the present invention, a hydrophilichigh-molecular-weight compound is dispersed in an aqueous solution containing a hydrophilic monomer. The dispersed hydrophilic high-molecular-weight compound is dissolved by heat of neutralization (heat of hydration) and/or heat of polymerization generated in the process of producing a hydrophilic polymer.

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Himeji, Japan

Yoshiro Mitsukami