Abstract: Provided is a particulate water absorbent with which an absorbent body having an excellent speed of incorporating liquid and enabling reduction in release amount can be produced. The particulate water absorbent contains poly(meth)acrylic acid (salt)-based water-absorbing resin particles as a main component, and the particulate water absorbent includes a cavity that is a space connecting to outside and a void that is a closed space not connecting to outside, in which a cavity ratio to a total volume is 10% by volume or more, and a void ratio to a total volume is 0.5% by volume or less.

Abstract: A water absorbent agent having a high water absorption multiplying factor where stickiness after absorbing liquid can be reduced when used as a hygienic material is produce by a method for manufacturing the water absorbing agent. The method for manufacturing a water absorbent agent having a centrifuge retention capacity (CRC) of 30 g/g or greater, includes subjecting an aqueous solution of a monomer that includes an acrylic acid (salt) to a polymerization step, a drying step, and a surface cross-linking step, and a step for adding ?-hydroxycarboxylic acid (salt) before the drying step. The atomic weight of the soluble portion eluted when the water absorbent agent absorbs liquid and swells can be reduced by the ?-hydroxycarboxylic acid (salt) before the drying step to reduce the stickiness of the water absorbent agent after absorption of liquid, which leads to discomfort during use of disposable diapers and the like.

Abstract: It is an object of the present invention to provide a novel water-absorbing sheet that can meaningfully reduce the return amount even when introduction of a liquid occurs intermittently for several times (particularly, three or more times) under a situation with no load, and the amount of introduction of the liquid becomes large.

Abstract: The present invention provides a contraction agent for a water-absorbing resin that is used as a proppant in stratum hydraulic fracturing, the contraction agent containing: a metal ion-containing substance and a breaking agent for water-absorbing resins used in stratum hydraulic fracturing; and an iron ion-containing substance and/or ascorbic acid, and/or a persulfate. Also provided is a kit for use in stratum hydraulic fracturing, the kit provided with a swelling agent containing a water-absorbing resin, an iron ion-containing substance, and ascorbic acid, the kit being for stratum hydraulic fracturing, wherein the kit consists of A) a proppant containing a water-absorbing resin, and B) a contraction agent for the water-absorbing resin containing a metal ion-containing substance.

Abstract: The purpose of the present invention is to provide a particulate water absorbing agent having both a high water absorption multiplying factor and a high water absorption rate and a method for manufacturing the same. The present invention is a particulate water absorbing agent for which CRC is 30 to 50 g/g, wherein the weight average particulate diameter (D50) is 200-600 ?m, and the DRC index given by the following formula is a specific value (for example, 43, 30, or 20) or less: DRC index=(49?DRC5min [g/g])/(D50 [?m]/1000).

Abstract: The present invention provides a water-absorbing sheet suitable for a hygienic material such as a disposable diaper. The water-absorbing sheet in accordance with an aspect of the present invention includes: a first base material; a second base material; and a particulate water-absorbing agent sandwiched between the first base material and the second base material, at least one of the first base material and the second base material being a water-permeable base material, and at least part of the particulate water-absorbing agent satisfying the following physical properties (1), (2), and (3): (1) a centrifuge retention capacity (CRC) is 30 g/g to 50 g/g; (2) a mass average particle diameter (D50) is 200 ?m to 600 ?m; and (3) a DRC index defined by the following Formula (a) is 43 or less: DRC index=(49?DRC5 min)/(D50/1000)?? Formula (a).

Abstract: A water absorbent resin (water absorbing agent) and method for producing it are provided which improve, in a water absorbent article (in particular, a diaper) including a water absorbent resin as a water absorbing agent, the absolute absorption amount (g), liquid absorbing times (in particular, liquid absorbing times at the second instance and later), re-wet (g), and diffusion distance (%) of the water absorbent article. A particulate water absorbing agent of the present invention has a CRC, a proportion of particles with sizes of 600 ?m to 150 ?m as defined through a standard-sieve classification, an SST, and the value of the difference between an FST and the SST each within a predetermined range.

Abstract: An object of the present invention is to provide a method for producing water absorbent resin powder in which permeability potential (SFC) is improved while a water absorbing rate (FSR) is being kept. The method is a method for producing water absorbent polyacrylic acid (salt) resin powder including the steps of: (i) polymerizing an acrylic acid (salt) monomer aqueous solution; (ii) during or after the step of (i), performing gel grinding of a hydrogel crosslinked polymer obtained by the polymerization, wherein the hydrogel crosslinked polymer has resin solid content of 10 wt % to 80 wt %, and the gel grinding is carried out with gel grinding energy (GGE) of 18 [J/g] to 60 [J/g]; (iii) drying a particulate hydrogel crosslinked polymer obtained by the gel grinding, wherein the drying is performed at 150° C. to 250° C.; and (iv) carrying out a surface treatment to the particulate hydrogel crosslinked polymer thus dried.

Abstract: An object of the present invention is to provide (i) a water absorbent agent composition which has an excellent additional function (a deodorizing function in particular), which stably carries out the additional function even after being stored for a long term, and which is less stressful to skin when used as an absorbent article, (ii) a method for producing the water absorbent agent composition, and (iii) an absorbent core and an absorbent article. The water absorbent agent composition contains: a polycarboxylic acid (salt)-based water absorbent resin as a main component; a natural ingredient; and a temporal deterioration preventing agent. Further, a water absorbent agent composition is produced by simultaneously or separately mixing a natural ingredient and a temporal deterioration preventing agent with a water absorbent resin which is a crosslinked polymer of unsaturated monomers having carboxylic acid and/or a salt thereof.

Abstract: It is an object to provide a particulate water-absorbing agent having a high fluid retention capacity under pressure and reduced moisture absorption blocking properties, and a method for producing the same. A particulate water-absorbing agent including a water-insoluble metal phosphate including an anion of a phosphoric acid compound and a divalent or trivalent metal cation, the water-insoluble metal phosphate having a crystallite size of less than 0.15 ?m, wherein the particulate water-absorbing agent has a fluid retention capacity under pressure of 2.06 kpa of 20 g/g or more.

Abstract: The purpose of the present invention is to provide a particulate water absorbing agent having both a high water absorption multiplying factor and a high water absorption rate and a method for manufacturing the same. The present invention is a particulate water absorbing agent for which CRC is 30 to 50 g/g, wherein the weight average particulate diameter (D50) is 200-600 ?m, and the DRC index given by the following formula is a specific value (for example, 43, 30, or 20) or less: DRC index=(49?DRC5min [g/g])/(D50 [?m]/1000).

Abstract: The purpose of the present invention is to provide a water absorbent agent having a high water absorption multiplying factor with which stickiness after absorbing liquid can be reduced when used as a hygienic material, and a method for manufacturing the same. The present invention is a method for manufacturing a water absorbent agent that has a centrifuge retention capacity (CRC) of 30 g/g or greater, comprising of subjecting an aqueous solution of a monomer that includes an acrylic acid (salt) to a polymerization step, a drying step, and a surface crosslinking step, wherein the method includes a step for adding ?-hydroxycarboxylic acid (salt) before the drying step.

Abstract: A water absorbent resin (water absorbing agent) and method for producing it are provided which improve, in a water absorbent article (in particular, a diaper) including a water absorbent resin as a water absorbing agent, the absolute absorption amount (g), liquid absorbing times (in particular, liquid absorbing times at the second instance and later), re-wet (g), and diffusion distance (%) of the water absorbent article. A particulate water absorbing agent of the present invention has a CRC, a proportion of particles with sizes of 600 ?m to 150 ?m as defined through a standard-sieve classification, an SST, and the value of the difference between an FST and the SST each within a predetermined range.

Abstract: The present invention (a) provides, at low cost, a water absorbing agent (i) that has a suppressed amount of generated dust and a suppressed amount of dust that increases over time and (ii) that also has a high absorption capacity without load, a high absorption capacity under load, a high vertical diffusion absorbency under load, and a high absorbency in a short period of time, and (b) also provides a method for evaluating, in a short period of time, an amount of dust that increases over time. A particulate water absorbing agent of the present invention includes: a surface crosslinked polyacrylic acid (salt)-based water absorbent resin as a main component; a hydrophilic polymer compound; and a stabilizing agent.

Abstract: A water absorbent resin (water absorbing agent) and method for producing it are provided which improve, in a water absorbent article (in particular, a diaper) including a water absorbent resin as a water absorbing agent, the absolute absorption amount (g), liquid absorbing times (in particular, liquid absorbing times at the second instance and later), re-wet (g), and diffusion distance (%) of the water absorbent article. A particulate water absorbing agent of the present invention has a CRC, a proportion of particles with sizes of 600 ?m to 150 ?m as defined through a standard-sieve classification, an SST, and the value of the difference between an FST and the SST each within a predetermined range.

Abstract: [Problem] To provide a dust reducer which suppresses blocking against moisture absorption and has a reduced amount of dust generation, without impairing the water absorption physical properties that are required from a water absorbing agent, such as water absorption capacity under load; a method for producing a water absorbing agent using the dust reducer; and a water absorbing agent in which blocking against moisture absorption is suppressed and which has a reduced amount of dust generation. [Solution] A dust reducer for a water absorbing agent containing a surface crosslinked polyacrylic acid (salt)-based water absorbent resin as a main component, wherein the dust reducer is a multi-component metal compound which has a hydrotalcite structure and contains a hydroxyl group and two kinds of metal cations that are divalent and trivalent.

Abstract: The present invention provides a contraction agent for a water-absorbing resin that is used as a proppant in stratum hydraulic fracturing, the contraction agent containing: a metal ion-containing substance and a breaking agent for water-absorbing resins used in stratum hydraulic fracturing; and an iron ion-containing substance and/or ascorbic acid, and/or a persulfate. Also provided is a kit for use in stratum hydraulic fracturing, the kit provided with a swelling agent containing a water-absorbing resin, an iron ion-containing substance, and ascorbic acid, the kit being for stratum hydraulic fracturing, wherein the kit consists of A) a proppant containing a water-absorbing resin, and B) a contraction agent for the water-absorbing resin containing a metal ion-containing substance.

Abstract: It is an object to provide a particulate water-absorbing agent having a high fluid retention capacity under pressure and reduced moisture absorption blocking properties, and a method for producing the same. A particulate water-absorbing agent including a water-insoluble metal phosphate including an anion of a phosphoric acid compound and a divalent or trivalent metal cation, the water-insoluble metal phosphate having a crystallite size of less than 0.15 mm, wherein the particulate water-absorbing agent has a fluid retention capacity under pressure of 2.06 kpa of 20 g/g or more.

Abstract: The present invention provides a method for producing a water absorbent resin particle, in high productivity, not only in a controlled manner of particle size but also enhancing fundamental property (absorption capacity or absorption capacity against pressure) of a water absorbent resin.

Abstract: The present invention provides a water-absorbing agent that includes water-absorbent resin particles as essential components and is suitable for a sanitary material. A water-absorbing agent of the present invention includes water-absorbent resin particles obtained by polymerizing an unsaturated monomer having an acid group. The water-absorbing agent has centrifuge retention capacity (CRC) of 5 to 20 g/g and includes: a compound with a structure unit derived from polyalkyleneglycol other than the unsaturated monomer; and a multivalent metal salt, and accordingly the water-absorbing agent has high saline flow conductivity (SFC) in a range of the above centrifuge retention capacity (CRC).