Sumitomo Seika Chemicals Co., Ltd.

Yasuhiro Nawata

Masayoshi Handa

Takayasu Taniguchi

Masato Fujikake

Tatsuya Oida

Hiromu Kobushi

Kenya Matsuda

Morio Nakamura

Hideki Yokoyama

Junichi Takatori

Tomoki Kawakita

Shinya Fukudome

Yuji Kinpara

Kimihiko Kondo

Magoto Shirakawa

Masakazu Yamamori

Shioko Yoshinaka

A purpose of the present invention is to reduce odor of a water-absorbent resin during absorption of water. Such the invention is attained by a process for production of a water-absorbent resin by subjecting a water-soluble ethylenically unsaturated monomer to reversed-phase suspension polymerization. The process comprises the following steps (A) to (C): (A) adding an aqueous solution of water-soluble ethylenically unsaturated monomer to a petroleum hydrocarbon dispersion medium to disperse the aqueous solution in the dispersion medium; (B) adding a surfactant to the emulsion to further disperse the emulsion; and (C) performing the reversed-phase suspension polymerization using a water-soluble radical polymerization initiator, optionally in the presence of an internal-crosslinking agent.

Process for production of water-absorbent resin

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 water-absorbent resin composition having an antimicrobial property, which suppresses the generation of dust of the antimicrobial agent. A water-absorbent resin composition comprising a water-absorbent resin and an antimicrobial agent comprising an inorganic compound carrying an antimicrobial metal, the water-absorbent resin composition being characterized in that the degree of generated dust of the water-absorbent resin composition is at most 100 CPM. The water-absorbent resin composition of the present invention can be suitably used as hygienic materials such as disposable diaper, sanitary napkin and incontinence pad; urine-absorbent materials for pets; materials for civil engineering and construction such as packing materials; drip absorbents; food freshness retaining materials such as cold-reserving agents; horticultural articles such as water-retaining materials for soils; and the like.

Water-absorbing resin 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

Process for preparing a water-absorbent resin comprising carrying out a reversed-phase suspension polymerization in multi-steps of two or more steps. The water-absorbent resin is prepared by subjecting a water-soluble ethylenically unsaturated monomer to the reversed phase suspension polymerization. This process for preparing a water-absorbent resin involves adding an aminocarboxylic acid compound to at least one step in the second and subsequent steps to carry out the polymerization reaction. The resulting water-absorbent resin can be suitably used in a hygienic material. The water-absorbent resin has a high degree of water-retention, including a high degree of water absorption under pressure. It also has a high water absorption rate, and contains only a small amount of water-soluble substances.

Process for production of water-absorbing 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

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.

Process for producing water-absorbing resin

A process for producing a water-absorbent resin particle comprising subjecting a water-soluble ethylenically unsaturated monomer to a reverse phase suspension polymerization, characterized in that the process for producing a water-absorbent resin particle comprises the steps of (A) subjecting the water-soluble ethylenically unsaturated monomer to a first-step reverse phase suspension polymerization in a hydrocarbon-based solvent using a water-soluble radical polymerization initiator in the presence of a surfactant and/or a polymeric protective colloid, and optionally an internal crosslinking agent; (B) carrying out at least one step of the procedures of adding an aqueous solution of a water-soluble ethylenically unsaturated monomer containing a water-soluble radical polymerization initiator and optionally an internal crosslinking agent to a reaction mixture after the termination of the first-step reverse phase suspension polymerization in a state that the surfactant and/or the polymeric protective colloid is dissolved in the hydrocarbon-based solvent, and subsequently subjecting the mixture to a reverse phase suspension polymerization; and (C) post-crosslinking the resulting water-absorbent resin.

Process for production of water-absorbing resin particles

A process for preparing a water-absorbent resin is provided which enables the water-absorbent resin to ensure the reduction in the release amount of liquid and the increase in the liquid diffusibility. In the preparation process, the water-absorbent resin is prepared by polymerization of a water-soluble ethylenic unsaturated monomer. The polymerization of the water-soluble ethylenic unsaturated monomer is allowed to take place in the presence of a water-absorbent resin having a water-absorbing rate different from that of a water-absorbent resin resulting from polymerization of the water-soluble ethylenic unsaturated monomer. In a preferred mode, the polymerization is performed by a reversed-phase suspension polymerization method.

Growing community of inventors

Himeji, Japan

Yasuhiro Nawata