Abstract: Provided are: a water-absorbing agent achieving, in a balanced manner, both good physical properties and a decrease in speed of coloration with lapse of time even if the water-absorbing agent has a high moisture absorbing speed due to having a large specific surface area; and an absorbent body having a low ratio of pulp and achieving, in a balanced manner, both good physical properties suitable for a thin disposable diaper and a decrease in speed of coloration with lapse of time.

Abstract: Provided is an absorbent body that, for example, in a case where the absorbent body has been used in an absorbent article, such as a thin disposable diaper, having an absorbent body with a low proportion of fiber material (hydrophilic fibers) such as pulp, enables the absorbent article such as a disposable diaper to have an improved liquid trapping function on second and subsequent urinations over the conventional ones and particularly to have an increased amount of liquid trapped under load on the second and subsequent urinations over the conventional ones. Also provided is a water-absorbing resin that is used in the absorbent body and has an increased absorption capacity under load on the second and subsequent urinations over the conventional ones. The absorbent body includes a water-absorbing resin having a gel expansion force under a load of 4.83 kPa of 26 N or more.

Abstract: The present invention provides an easy method for producing a water absorbent agent that has a low moisture content and that has a small dust generation amount without decreasing various physical properties. A present inventive method for producing a water absorbent agent of the present invention includes mixing not lower than 0.06 parts by mass and not higher than 5 parts by mass of an inorganic acid alkali metal salt powder with 100 parts by mass of a water-absorbent resin in an indefinite ground form.

Abstract: Provided is a water-absorbing agent which maintains a certain degree of liquid permeability and water absorption speed while also reducing re-wet in a disposable diaper, without the use of costly raw materials or costly apparatuses. The water-absorbing agent of the present invention contains a polyacrylic acid salt-based water-absorbing resin as a main component and has physical properties falling within a specific range, the physical properties being saline flow conductivity (SFC), gap fluid retention property under pressure, and a proportion of particles having a particle diameter of not less than 150 ?m and less than 710 ?m.

Abstract: From a view pint of decreasing an out of spec product after surface crosslinking, particularly, when an alkylene carbonate compound is used as a surface crosslinking agent, influence due to an air temperature is great, and it is necessary to reduce ethylene glycol which is produced as a byproduct. There is provided a process for producing a polyacrylic acid (salt)-based water absorbent resin powder, comprising storing a non-polymerized organic compound being a raw material (modified raw material) of a water absorbent resin powder in a heated state, thereafter, mixing the non-polymerized organic compound with other compound at a predetermined ratio and, further, mixing the mixture into a water absorbent resin powder.

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: The present invention provides (i) a water absorbing agent which is excellent in a water absorbing physical properties, in particular water absorbing speed and has a great bulk specific gravity and (ii) a method for producing the water absorbing agent. The method for producing the water absorbing agent includes a surfactant adding step of adding a surfactant whose HLB is 10 or less. The surfactant adding step is the step of adding a dispersion liquid, which contains the surfactant equivalent to 30 parts by weight to 150 parts by weight, relative to 1000000 parts by weight of a water absorbent resin solid content, and the surfactant adding step is carried out after a drying step. Further, in a case where a water-soluble polyvalent metal salt adding step is carried out after the drying step, the surfactant adding step is carried out after the water-soluble polyvalent metal salt adding step.

Abstract: Provided is a water-absorbing agent which maintains a certain degree of liquid permeability and water absorption speed while also reducing re-wet in a disposable diaper, without the use of costly raw materials or costly apparatuses. The water-absorbing agent of the present invention contains a polyacrylic acid salt-based water-absorbing resin as a main component and has physical properties falling within a specific range, the physical properties being saline flow conductivity (SFC), gap fluid retention property under pressure, and a proportion of particles having a particle diameter of not less than 150 ?m and less than 710 ?m.

Abstract: From a view point of reduction in an out of spec product after surface crosslinking, particularly, when an alkylene carbonate compound is used as a surface crosslinking agent, influence by an air temperature is great, and it is necessary to reduce ethylene glycol which is produced as a byproduct, and there is provided a process for producing a polyacrylic acid (salt)-based water absorbent resin powder, comprising a step of polymerizing an aqueous acrylic acid (salt)-based monomer solution, a step of drying the resulting polymer, an optional grinding•classifying step, and a surface crosslinking step, wherein in the surface crosslinking step, (1) a surface crosslinking agent containing an alkylene carbonate compound and a polyhydric alcohol compound is mixed into a water absorbent resin powder, the mixture is heat-reacted and, further, simultaneously with, or separately from the mixing, an ion reactive surface crosslinking agent is mixed, and/or (2) mixing treatment of mixing a surface crosslinking agent sol

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 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: A process according to the present invention for production of water-absorbable polyacrylic acid resin powder, including: (a) polymerizing an acrylic acid-based monomer aqueous solution containing bubbles, and (b) drying a hydrogel crosslinked polymer thus obtained in the step of polymerizing, further includes (c) lowering solubility of dissolved gas in a monomer aqueous solution in the presence of a surfactant and/or a dispersing agent, so as to generate the bubbles in the acrylic acid-based monomer aqueous solution. With this arrangement, it is possible to provide white water-absorbable resin with better water absorbing rate, keeping or without significantly losing the other properties (permeability potential, bulk specific gravity, surface tension, absorbency against pressure, impact resistance, etc.

Abstract: The present invention provides (i) a water absorbing agent which is excellent in a water absorbing physical properties, in particular water absorbing speed and has a great bulk specific gravity and (ii) a method for producing the water absorbing agent. The method for producing the water absorbing agent includes a surfactant adding step of adding a surfactant whose HLB is 10 or less. The surfactant adding step is the step of adding a dispersion liquid, which contains the surfactant equivalent to 30 parts by weight to 150 parts by weight, relative to 1000000 parts by weight of a water absorbent resin solid content, and the surfactant adding step is carried out after a drying step. Further, in a case where a water-soluble polyvalent metal salt adding step is carried out after the drying step, the surfactant adding step is carried out after the water-soluble polyvalent metal salt adding step.

Abstract: Provided is a water absorbent resin having excellent liquid permeability, water absorbent speed, anti-impact stability, and weather resistance. Provided is a polyacrylic acid (salt)-based water absorbent resin powder in which the water absorption capacity without load (CRC) is 30 to 45 [g/g], the water absorption capacity under load (AAP 0.3) is 20 to 35 [g/g], the water absorption capacity under load (AAP 0.7) is 10 to 28 [g/g], and the weight average particle diameter (D50) is 300 to 500 ?m, characterized by including p-methoxyphenol; having a degradable soluble component (0.05% L-A (saline) for 2 hours/60° C., one hour extraction rinse/room temperature) of 40% by weight or less; and having a internal gas bubbles ratio of 0.1 to 2.5%, as specified by the following equation.

Abstract: Provided is a water absorbent resin having excellent liquid permeability, water absorbent speed, anti-impact stability, and weather resistance. Provided is a polyacrylic acid (salt)-based water absorbent resin powder in which the water absorption capacity without load (CRC) is 30 to 45 [g/g], the water absorption capacity under load (AAP 0.3) is 20 to 35 [g/g], the water absorption capacity under load (AAP 0.7) is 10 to 28 [g/g], and the weight average particle diameter (D50) is 300 to 500 ?m, characterized by including p-methoxyphenol; having a degradable soluble component (0.05% L-A (saline) for 2 hours/60° C., one hour extraction rinse/room temperature) of 40% by weight or less; and having a internal gas bubbles ratio of 0.1 to 2.5%, as specified by the following equation.

Abstract: A water absorbent resin having less fine powder or powdery dust and a controlled particle size is provided, and the water absorption rate of the water absorbent resin is increased by a simple method at low cost, while maintaining or improving other physical properties such as liquid permeability.

Abstract: From a view pint of decreasing an out of spec product after surface crosslinking, particularly, when an alkylene carbonate compound is used as a surface crosslinking agent, influence due to an air temperature is great, and it is necessary to reduce ethylene glycol which is produced as a byproduct. There is provided a process for producing a polyacrylic acid (salt)-based water absorbent resin powder, comprising storing a non-polymerized organic compound being a raw material (modified raw material) of a water absorbent resin powder in a heated state, thereafter, mixing the non-polymerized organic compound with other compound at a predetermined ratio and, further, mixing the mixture into a water absorbent resin powder.

Abstract: From a viewpoint of reduction in an out of spec product after surface crosslinking, particularly, when an alkylene carbonate compound is used as a surface crosslinking agent, influence by an air temperature is great, and it is necessary to reduce ethylene glycol which is produced as a byproduct, and there is provided a process for producing a polyacrylic acid (salt)-based water absorbent resin powder, comprising a step of polymerizing an aqueous acrylic acid (salt)-based monomer solution, a step of drying the resulting polymer, an optional grinding•classifying step, and a surface crosslinking step, wherein in the surface crosslinking step, (1) a surface crosslinking agent containing an alkylene carbonate compound and a polyhydric alcohol compound is mixed into a water absorbent resin powder, the mixture is heat-reacted and, further, simultaneously with, or separately from the mixing, an ion reactive surface crosslinking agent is mixed, and/or (2) mixing treatment of mixing a surface crosslinking agent solu

Abstract: A water absorbent resin having less fine powder or powdery dust and a controlled particle size is provided, and the water absorption rate of the water absorbent resin is increased by a simple method at low cost, while maintaining or improving other physical properties such as liquid permeability.

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.