Sumitomo Seika Chemicals Co., Ltd.

Masayoshi Handa

Yasuhiro Nawata

Yuichi Onoda

Atsushi Heguri

Takayasu Taniguchi

Kenji Tanimura

Junichi Takatori

Kimihiko Kondo

Kiyoshi Yamaguchi

Hiromu Kobushi

Masato Fujikake

Hiroki Yabuguchi

Tetsuhiro Hinayama

Shinya Fukudome

Nobuhiro Maeda

Sachi Kikuno

Koji Ueda

Haruka Inaba

Hideki Matsushita

Syuji Tsuno

Junichi Maruo

There is disclosed a method for producing water-absorbent resin particles, comprising a polymerization step that includes mixing an oily liquid comprising a hydrocarbon dispersing medium and a surfactant, and an aqueous liquid comprising an aqueous solvent and a water-soluble ethylenically unsaturated monomer, forming a suspension comprising an oily liquid and an aqueous liquid dispersed in the oily liquid, and polymerizing the water-soluble ethylenically unsaturated monomer in the suspension. The HLB of the surfactant is 6 or greater, and the temperature of the suspension is kept at 35&#xb0; C. or higher during the period from initial mixing of the oily liquid and aqueous liquid until complete mixing of the entire amounts.

Method for producing water absorbent resin particles

The present invention provides a method for producing water-absorbing resin particles having high equilibrium swelling capacity, a high water-absorption rate or high initial swelling capacity, and an appropriate particle size that achieves good handling performance; water-absorbing resin particles obtained by the method; and a water blocking material and an absorbent article which include the water-absorbing resin particles. The present invention is a method for producing water-absorbing resin particles, which comprises: preparing a hydrogel polymer by reversed-phase suspension polymerization of a water-soluble ethylenically unsaturated monomer in a hydrocarbon solvent in the absence of an internal crosslinking agent but in the presence of a surfactant with an HLB of 8 to 12; carrying out a post-crosslinking reaction of the hydrogel polymer whose moisture content is adjusted to 30 to 110 mass % based on a water-soluble ethylenically unsaturated monomer component that composes the hydrogel polymer.

Process for production of water-absorbing resin particles, water-absorbing resin particles, water-stopping material, and absorbent article

The present invention may provide a process for producing a water-absorbent resin by employing a reversed suspension polymerization method, by which a water-absorbent resin having a small particle size and a narrow particle size distribution can be produced. The process for producing a water-absorbent resin may include subjecting a water-soluble ethylenically unsaturated monomer to a reversed phase suspension polymerization in a petroleum hydrocarbon dispersion medium containing a surfactant and a polymeric dispersion agent, wherein the polymeric dispersion agent is a polymeric protective colloid having a weight average molecular weight (Mw) of 2,000 to 15,000 and a molecular weight distribution (Mw/number average molecular weight (Mn)) of 3 to 50.

Method for producing water-absorbent resin

A water-absorbent sheet structure comprises a structure in which an absorbent layer containing a water-absorbent resin (A) and a water-absorbent resin (B) is sandwiched with fibrous webs from an upper side and a lower side of the absorbent layer, characterized in that the water-absorbent resin (A) and the water-absorbent resin (B) are contained in a total amount of from 100 to 1,000 g/m, and that the water-absorbent resin (A) and the water-absorbent resin (B) have the following properties: (1) the water-absorbent resin (A) having a water-retention capacity of saline solution (Ra) from 15 to 55 g/g; (2) the water-absorbent resin (B) having a water-retention capacity of saline solution (Rb) from 10 to 50 g/g; and (3) Ra and Rb mentioned above satisfies the relationship of the following formula: Ra&#x2212;Rb&#x2267;(g/g). The water-absorbent sheet structure of the present invention exhibits some effects that a water-absorbent sheet structure has excellent shape retaining ability even when the structure is thin, so that the water-absorbent sheet structure does not undergo deformation of the form before liquid absorption or after the absorption, and is capable of sufficiently exhibiting absorbent properties.

Water-absorbent sheet structure

Disclosed is a water-absorbent resin particle in which the water-absorption rate of physiological saline is 1 second to 15 seconds, the median particle size is 100 &#x3bc;m to 600 &#x3bc;m, and the residual volatile component content is 1.5% by weight or less.

Water absorbing resin particles, method for manufacturing water absorbing resin particles, absorption body, absorptive article, and water-sealing material

There is disclosed a method for producing water-absorbent resin particles comprising a step that includes reversed-phase suspension polymerization of a water-soluble ethylenically unsaturated monomer in a suspension containing a surfactant that comprises a surfactant that comprises a fatty acid ester of sorbitan or sorbitol, or derivative thereof, and a hydrocarbon dispersion medium. The fatty acid ester includes a lauric acid ester and at least one kind of other ester selected from the group consisting of palmitic acid esters, stearic acid esters and behenic acid esters. The proportion of the peak area for lauric acid ester is 30-60%, based on the total peak area for fatty acid esters in the GPC chromatogram obtained from the fatty acid esters, and the proportion of the total peak area for other ester is 10-50%.

Method for producing water-absorbent resin particles

A method for producing a water-absorbent resin by a reversed-phase suspension polymerization method, includes step 1 of dispersing a first aqueous solution containing a partially neutralized product (A) of a water-soluble ethylenically unsaturated monomer having acid groups in the molecule in a petroleum-type hydrocarbon dispersion medium in the presence of a dispersing agent, and then polymerizing the resulting dispersion to obtain a slurry containing primary particles of a polymer, and step 2 of adding a second aqueous solution containing a partially neutralized product (B) of a water-soluble ethylenically unsaturated monomer having acid groups in the molecule to the slurry obtained in step 1, and then polymerizing the mixture to obtain a slurry in which the primary particles are agglomerated. In the method, a molar neutralization degree X of the partially neutralized product (A) and a molar neutralization degree Y of the partially neutralized product (B) are defined.

The object of the present invention is to provide a water-absorbing resin compound, wherein the water-absorbing resin compound can retain antibacterial properties of an antibacterial metal to suppress the emission of unpleasant odors even when an organic material exists in a system in the case of using an eluting-type antibacterial agent. Thus, the present invention relates to a water-absorbing resin compound, which comprises a water-absorbing resin, an antibacterial agent having a porous material incorporating an antibacterial metal, and a metal chelating agent. Further, the present invention also relates to an absorbing material, which comprises a water-absorbing resin compound of the present invention, and a hydrophilic fiber as well as an absorbing product, which comprises a liquid-permeable sheet and a liquid-non-permeable sheet, and an absorbing material comprising a water-absorbing resin compound of the present invention, and a hydrophilic fiber between the liquid-permeable sheet and the liquid-non-permeable sheet.

Water-absorbing resin compound

A method for producing a water-absorbent resin including the step of subjecting a water-soluble ethylenically unsaturated monomer to a reversed phase suspension polymerization in a petroleum hydrocarbon dispersion medium in the presence of a radical polymerization initiator and a dispersion stabilizer, wherein the method is characterized by the use of an ether-ester type nonionic surfactant as the dispersion stabilizer, and a water-absorbent resin obtained by the method, wherein the water-absorbent resin has a water-retention capacity of saline solution of 25 g/g or more, a water-absorption rate of saline solution of 50 seconds or less, and a flow index under moisture absorption of 70% or more. According to the method of the present invention, a water-absorbent resin having high water-retention capacity, excellent water-absorption rate, and further having excellent flowability under moisture absorption can be produced. The water-absorbent resin having the specified physical properties as described above can enhance properties of hygienic materials, and the resin can be suitably used in the production of the hygienic materials.

Method for producing water-absorbent resin, and water-absorbent resin obtained by same

A water-absorbent sheet composition containing a structure in which an absorbent layer containing a water-absorbent resin and an adhesive is sandwiched with two or more sheets of hydrophilic nonwoven fabrics, wherein the water-absorbent sheet composition has a structure in which the absorbent layer is separated in divided parts of a primary absorbent layer and a secondary absorbent layer with a water-permeable substrate having a water permeability index of from 20 to 90, and wherein the water-absorbent resin is contained in the absorbent layer in an amount of from 100 to 1000 g/m. The water-absorbent sheet composition of the present invention exhibits some excellent effects that the water-absorbent sheet composition is capable of accomplishing thinning and avoidance of gel blocking phenomenon and liquid leakage, while obtaining basic properties as a water-absorbent sheet composition at a high level, even for a water-absorbent sheet composition containing a very small amount of pulps.

Water-absorbent sheet composition

The present invention relates to a method of producing water-absorbent resin particles in which a median particle size of primary particles (d) and a median particle size of secondary particles (D) satisfy the relationship of the formula, 5d/3+150&#x3c;D&#x3c;5d+150, comprising the steps of:

Process for production of water-absorbable resin particle, and water-absorbable resin particle produced by the process

A method for producing a water-absorbent resin, characterized in that a precursor of the water-absorbent resin obtained by polymerizing a water-soluble ethylenically unsaturated monomer is subjected to a post-crosslinking reaction in the presence of a compound having plural hydrazide groups. The water-absorbent resin obtained by the method for producing a water-absorbent resin of the present invention is excellent in properties such as water-retention capacity, water-absorption capacity under load, and gel strength, and also gives consideration to safety of the water-absorbent resin by reducing water-soluble substance. Therefore, the water-absorbent resin of the present invention can be suitably used, for example, in hygienic materials such as disposable diaper, incontinence pad and sanitary napkin, in particular, in disposable diaper.

Process for production of water-absorbable resin

The present invention provides a process for producing water-absorbing resin particles which possess a high water retention capacity (absorbing capacity), a high water-absorbing capacity under pressure, and a high gel strength and a small amount of water-soluble substance and is favorably usable in sanitary materials; water-absorbing resin particles obtained by the process; and absorbent materials and absorbent articles made by using the particles. More specifically, the water-absorbing resin particles are produced by a process for producing water-absorbing resin particles, comprising a step of a post-crosslinking reaction by adding a post-crosslinking agent in at least two stages to a water-absorbing resin particle precursor obtained by polymerization of a water-soluble ethylenic unsaturated monomer to carry out the post-crosslinking reaction.

Process for producing water-absorbing resin particles, water-absorbing resin particles made by the process, and absorbent materials and absorbent articles made by using the particles

Water-absorbing resin composition

A process for preparing a water-absorbent resin made from an &#x3b1;,&#x3b2;-unsaturated carboxylic acid as an essential monomer characterized in that the process comprises allowing a metal chelating agent to be present at any step in the process in an amount of 0.001 to 6 parts by weight, based on 100 parts by weight of the &#x3b1;,&#x3b2;-unsaturated carboxylic acid; and adding a reducing agent or an oxidizing agent thereto in an amount of 0.001 to 6 parts by weight, based on 100 parts by weight of the &#x3b1;,&#x3b2;-unsaturated carboxylic acid before initiation of drying and/or during drying of a gelated product containing a water-absorbent resin obtained by polymerization.

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Himeji, Japan

Masayoshi Handa