Patents by Inventor Yasuhiro Nawata
Yasuhiro Nawata has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9074022Abstract: 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.Type: GrantFiled: April 26, 2007Date of Patent: July 7, 2015Assignee: SUMITOMO SEIKA CHEMICALS CO., LTD.Inventors: Hideki Yokoyama, Yasuhiro Nawata
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Patent number: 8981176Abstract: 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.Type: GrantFiled: November 30, 2010Date of Patent: March 17, 2015Assignee: Sumitomo Seika Chemicals Co., Ltd.Inventors: Takayasu Taniguchi, Masayoshi Handa, Yasuhiro Nawata
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Publication number: 20140094570Abstract: The present invention provides a water-absorbent resin produced by a reversed-phase suspension polymerization method, which contains a small amount of a petroleum hydrocarbon dispersion medium remaining therein used in reversed-phase suspension polymerization, and thus reducing an odor originating from the petroleum hydrocarbon dispersion medium, when the water-absorbent resin absorbs water, and also which is suitable for use in hygienic materials; an absorbent material and an absorbent article. More particularly, the present invention provides a water-absorbent resin obtained by subjecting an aqueous solution of a water-soluble ethylenically unsaturated monomer to reversed-phase suspension polymerization in a petroleum hydrocarbon dispersion medium in the presence of a surfactant, wherein the amount of the petroleum hydrocarbon dispersion medium remaining in the water-absorbent resin is 2,000 ppm or less; and an absorbent material and an absorbent article using the same.Type: ApplicationFiled: December 9, 2013Publication date: April 3, 2014Applicant: Sumitomo Seika Chemicals Co., Ltd.Inventors: Hideki Yokoyama, Yasuhiro Nawata
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Patent number: 8524797Abstract: 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.Type: GrantFiled: October 24, 2005Date of Patent: September 3, 2013Assignee: Sumitomo Seika Chemicals Co., Ltd.Inventors: Takayasu Taniguchi, Tatsuya Oida, Yasuhiro Nawata
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Patent number: 8383696Abstract: 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.Type: GrantFiled: November 23, 2011Date of Patent: February 26, 2013Assignee: Sumitomo Seika Chemicals Co., Ltd.Inventors: Takayasu Taniguchi, Tatsuya Oida, Yasuhiro Nawata
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Patent number: 8378033Abstract: 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<D<5d+150, comprising the steps of: (1) subjecting a water-soluble ethylenically unsaturated monomer to a first-step reversed phase suspension polymerization reaction, in a petroleum hydrocarbon solvent, in the presence of a dispersion stabilizer, to give spherical primary particles having a median particle size (d) of from 30 to 130 ?m; (2) cooling the polymerization reaction solution, to precipitate the dispersion stabilizer; and (3) carrying out a second-step reversed phase suspension polymerization reaction by adding the water-soluble ethylenically unsaturated monomer for the second step to the polymerization reaction solution to agglomerate the primary particles, to give secondary particles having a median particle size (D) of from 200 to 500 ?m.Type: GrantFiled: April 20, 2007Date of Patent: February 19, 2013Assignee: Sumitomo Seika Chemicals Co., Ltd.Inventors: Masayoshi Handa, Yasuhiro Nawata
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WATER-ABSORBENT RESIN PARTICLE, METHOD FOR PRODUCTION THEREOF, AND ABSORBENT MATERIAL USING THE SAME
Publication number: 20120298913Abstract: A method for production of a water-absorbent resin particle which is excellent in a particle strength, and in which even after mechanical impact, a particle diameter retaining rate and a retaining rate of water absorption capacity under pressure are high, and an absorbent material using the same particle. The method includes the steps of polymerizing a water-soluble ethylenic unsaturated monomer using a water-soluble radical polymerization initiator, optionally in the presence of a crosslinking agent, to obtain a water-absorbent resin particle precursor, adding a post-crosslinking agent to crosslink a surface of the particle, adding an amorphous silica particle and adjusting the resulting particle to a moisture content of less than 10%, and subsequently adding moisture to adjust a final moisture content of the resulting particle to 10 to 20%.Type: ApplicationFiled: August 7, 2012Publication date: November 29, 2012Applicant: SUMITOMO SEIKA CHEMICALS CO., LTD.Inventors: Kimihiko Kondo, Takayasu Taniguchi, Yasuhiro Nawata -
Patent number: 8198376Abstract: 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.Type: GrantFiled: July 17, 2007Date of Patent: June 12, 2012Assignee: Sumitomo Seika Chemicals Co., Ltd.Inventors: Hiromu Kobushi, Masayoshi Handa, Yasuhiro Nawata
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Publication number: 20120070484Abstract: 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.Type: ApplicationFiled: November 23, 2011Publication date: March 22, 2012Inventors: Takayasu TANIGUCHI, Tatsuya Oida, Yasuhiro Nawata
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Patent number: 8084544Abstract: 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.Type: GrantFiled: June 30, 2006Date of Patent: December 27, 2011Assignee: Sumitomo Seika Chemicals Co., Ltd.Inventors: Shinya Fukudome, Junichi Takatori, Kenya Matsuda, Yasuhiro Nawata
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Patent number: 8003210Abstract: 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.Type: GrantFiled: May 10, 2006Date of Patent: August 23, 2011Assignee: Sumitomo Seika Chemicals Co., Ltd.Inventors: Hiromu Kobushi, Masayoshi Handa, Yasuhiro Nawata
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Publication number: 20110068300Abstract: 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.Type: ApplicationFiled: November 30, 2010Publication date: March 24, 2011Applicant: SUMITOMO SEIKA CHEMICALS CO., LTD.Inventors: Takayasu Taniguchi, Masayoshi Handa, Yasuhiro Nawata
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Patent number: 7868075Abstract: 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.Type: GrantFiled: April 7, 2004Date of Patent: January 11, 2011Assignee: Sumitomo Seika Chemicals Co., Ltd.Inventors: Takayasu Taniguchi, Masayoshi Handa, Yasuhiro Nawata
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Publication number: 20100331802Abstract: The present invention provides a water-absorbent resin produced by a reversed-phase suspension polymerization method, which contains a small amount of a petroleum hydrocarbon dispersion medium remaining therein used in reversed-phase suspension polymerization, and thus reducing an odor originating from the petroleum hydrocarbon dispersion medium, when the water-absorbent resin absorbs water, and also which is suitable for use in hygienic materials; an absorbent material and an absorbent article. More particularly, the present invention provides a water-absorbent resin obtained by subjecting an aqueous solution of a water-soluble ethylenically unsaturated monomer to reversed-phase suspension polymerization in a petroleum hydrocarbon dispersion medium in the presence of a surfactant, wherein the amount of the petroleum hydrocarbon dispersion medium remaining in the water-absorbent resin is 2,000 ppm or less; and an absorbent material and an absorbent article using the same.Type: ApplicationFiled: August 14, 2008Publication date: December 30, 2010Applicant: SUMITOMO SEIKA CHEMICALS CO., LTD.Inventors: Hideki Yokoyama, Yasuhiro Nawata
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Publication number: 20100273647Abstract: A water-absorbent resin is provided which is suitable for absorbing polymer-containing viscous liquids, wherein the specific surface area measured by the BET multipoint technique using krypton gas as the adsorption gas is no less than 0.05 m2/g, and the water retention capacity for 0.9 wt % physiological saline is 5-30 g/g.Type: ApplicationFiled: July 8, 2010Publication date: October 28, 2010Applicant: Sumitomo Seika Chemicals Co., Ltd.Inventors: Yasuhiro NAWATA, Masakazu YAMAMORI, Koji UEDA, Hideki YOKOYAMA, Masato FUJIKAKE
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Publication number: 20100256308Abstract: A method for producing a water-absorbent resin, characterized by adding an oxetane compound represented by the following general formula (1): wherein R1 is an alkyl group having 1 to 6 carbon atoms; R2 is an alkanediyl group having 1 to 6 carbon atoms; and X is an atomic group containing at least one group selected from the group consisting of carbonyl group, phosphoryl group, and sulfonyl group, to a water-absorbent resin precursor obtainable by polymerizing water-soluble ethylenically unsaturated monomers, and subjecting the components to a post-crosslinking reaction while heating; and a water-absorbent resin obtainable by the method as defined above, characterized in that the water-absorbent resin has a water-retention capacity of physiological saline of 30 g/g or more, a water-absorption capacity of physiological saline under load of 2.07 kPa of 28 mL/g or more, and a water-soluble substance of 20% by mass or less.Type: ApplicationFiled: September 9, 2008Publication date: October 7, 2010Applicant: SUMITOMO SEIKA CHEMICALS CO., LTD.Inventors: Junichi Takatori, Masayoshi Handa, Yasuhiro Nawata
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Publication number: 20100197491Abstract: A method for producing a water-absorbent resin, characterized by adding a bisoxetane compound represented by the following general formula (1): wherein R is an alkyl group having 1 to 6 carbon atoms; and n is an integer of from 0 to 6, to a water-absorbent resin precursor obtainable by polymerizing water-soluble ethylenically unsaturated monomers, and subjecting the components to a post-crosslinking reaction while heating; and a water-absorbent resin obtainable by the method, characterized in that the water-absorbent resin has a retention capacity of physiological saline of 30 g/g or more, an absorption capacity of physiological saline under a load of 2.07 kPa of 15 ml/g or more, and a water-soluble substance of 20% by mass or less.Type: ApplicationFiled: July 2, 2008Publication date: August 5, 2010Applicant: SUMITOMO SEIKA CHEMICALS CO., LTD.Inventors: Junichi Takatori, Masayoshi Handa, Yasuhiro Nawata
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Patent number: 7737231Abstract: A process for preparing a water-absorbent resin made from an ?,?-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 ?,?-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 ?,?-unsaturated carboxylic acid before initiation of drying and/or during drying of a gelated product containing a water-absorbent resin obtained by polymerization.Type: GrantFiled: December 27, 2002Date of Patent: June 15, 2010Assignee: Sumitomo Seika Chemicals Co., Ltd.Inventors: Masayoshi Handa, Takayasu Taniguchi, Yasuhiro Nawata, Masato Fujikake
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Patent number: 7713623Abstract: 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 isType: GrantFiled: March 12, 2004Date of Patent: May 11, 2010Assignee: Sumitomo Seika Chemicals Co., Ltd.Inventors: Kenya Matsuda, Yuji Kinpara, Tomoki Kawakita, Yasuhiro Nawata
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Publication number: 20090326162Abstract: 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.Type: ApplicationFiled: July 17, 2007Publication date: December 31, 2009Applicant: SUMITOMO SEIKA CHEMICALS CO., LTD.Inventors: Hiromu Kobushi, Masayoshi Handa, Yasuhiro Nawata