Abstract: Provided are a method for producing a recycled water-absorbing resin which achieves reduction in deterioration of water absorption performance and reduction in coloration, and a method for producing a water-absorbing resin with use of the recycled water-absorbing resin. The present disclosure relates to, for example, a method for producing a recycled water-absorbing resin from a used absorbent article, the method including: a urea removal step of removing urea so that a urea content in the recycled water-absorbing resin becomes 2 mass % or less; and a recovery step of recovering a water-absorbing property.

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: [Problem] To provide a particulate water-absorbing agent that can significantly reduce re-wet even when pressure is applied to the particulate water-absorbing agent from the outside when the particulate water-absorbing agent is in a swollen state. [Solution] A particulate water-absorbing agent comprising a surface-crosslinked polyacrylic acid (salt)-based water-absorbing resin as a main component and satisfying the following expression (1). AAP(2.06 kPa)+RCAP(2.06 kPa)?0.58×CRC+55.6??(1), wherein AAP (2.06 kPa) represents absorption capacity (g/g) under a pressure of 2.06 kPa, RCAP (2.06 kPa) represents retention capacity against pressure after swelling (g/g), and CRC represents absorption capacity without pressure (g/g).

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: 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: 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: [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: 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: [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.