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 relates to an absorbent suitable for use in a thin sanitary material/absorbent article having a high absorbent content and not prone to gel blocking, the absorbent having excellent liquid diffusibility (e.g. SFC) and minimal decrease in absorption ratio under pressure (e.g., AAP or PUP) even when a liquid permeation enhancer is added, and to a method for manufacturing the high-performance absorbent stably during actual production. The method is a method for manufacturing a polyacrylic acid (salt)-based absorbent, having a surface-crosslinking agent addition step for adding a solution of a surface-crosslinking agent, and a liquid permeation enhancer addition step for adding a liquid permeation enhancer, the liquid permeation enhancer addition step being performed after and/or at the same time as the surface-crosslinking agent addition step, the method characterized in that a surface crosslinking step for performing heat treatment in an atmosphere having a dew point of 45° C. to 100° C.

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 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 relates to an absorbent suitable for use in a thin sanitary material/absorbent article having a high absorbent content and not prone to gel blocking, the absorbent having excellent liquid diffusibility (e.g. SFC) and minimal decrease in absorption ratio under pressure (e.g., AAP or PUP) even when a liquid permeation enhancer is added, and to a method for manufacturing the high-performance absorbent stably during actual production. The method is a method for manufacturing a polyacrylic acid (salt)-based absorbent, having a surface-crosslinking agent addition step for adding a solution of a surface-crosslinking agent, and a liquid permeation enhancer addition step for adding a liquid permeation enhancer, the liquid permeation enhancer addition step being performed after and/or at the same time as the surface-crosslinking agent addition step, the method characterized in that a surface crosslinking step for performing heat treatment in an atmosphere having a dew point of 45° C. to 100° C.

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: 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).

Abstract: The present invention relates to an absorbent suitable for use in a thin sanitary material/absorbent article having a high absorbent content and not prone to gel blocking, the absorbent having excellent liquid diffusibility (e.g. SFC) and minimal decrease in absorption ratio under pressure (e.g., AAP or PUP) even when a liquid permeation enhancer is added, and to a method for manufacturing the high-performance absorbent stably during actual production. The method is a method for manufacturing a polyacrylic acid (salt)-based absorbent, having a surface-crosslinking agent addition step for adding a solution of a surface-crosslinking agent, and a liquid permeation enhancer addition step for adding a liquid permeation enhancer, the liquid permeation enhancer addition step being performed after and/or at the same time as the surface-crosslinking agent addition step, the method characterized in that a surface crosslinking step for performing heat treatment in an atmosphere having a dew point of 45° C. to 100° C.

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: To provide (i) a water-absorbing agent, having a water-absorbent resin as a main component, whose absorbency is high and liquid permeability is enhanced and (ii) a production method thereof. The water-absorbing agent of the present invention includes a water-absorbent resin obtained by polymerizing an unsaturated monomer having a carboxyl group and included in an aqueous monomer solution in the presence of at least a non high molecular compound having four or more functional groups each capable of forming a covalent bond with a carboxyl group.

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: A water absorbing agent includes water absorbent resin particles which are obtained by polymerizing a water-soluble ethylenic unsaturated monomer and which internally include a cross-linked structure, wherein a pressurized void average radius index is 140 or more. As a result, it is possible to provide a water absorbing agent which essentially includes water absorbent resin particles and is suitable for use in a sanitary material. Specifically, it is possible to improve not only a performance for absorbing and retaining aqueous liquid without pressure or under pressure but also (i) a performance for quickly absorbing aqueous liquid with a great help of a performance of a fibrous material, (ii) a performance for dispersing the aqueous liquid after absorbing the aqueous liquid, and (iii) a performance for retaining the aqueous liquid after absorbing the aqueous liquid.

Abstract: An object of the present invention is to provide a method for producing a water absorbing agent, whereby the ability to produce the water absorbing agent is enhanced or the amount of a residual surface crosslinking agent is reduced (or Anti-Caking property are enhanced) in the production of a water absorbing agent having high physical properties (particularly, high liquid permeability and Anti-Caking property), whereas the surface crosslinking step tends to be a rate-determining step in the current state of the art. In this method for producing a water absorbing agent, an additive selected from a polyvalent metal cation-containing compound, water-insoluble inorganic fine particles, and a cationic polymer compound is used, and surface crosslinking, particularly surface crosslinking with an alkylene carbonate compound, is performed under conditions where a temperature in a heat treatment system is controlled to be in a range from 100° C. to 300° C.

Abstract: A method for producing a water-absorbing resin comprises circulation of the water-absorbing resin in a predetermined amount in a pulverization step before a surface cross-linking step. At least a part of a classified polymer is supplied again to the same or a different pulverization step before the surface cross-linking step, wherein the circulation pulverization ratio in the pulverization step, represented by the following equation, is 1.10 to 1.50: (Circulation pulverization ratio)=(total supply amount of the water-absorbing resin to the pulverization step)/(total discharge amount of the water-absorbing resin at the drying step) wherein (total supply amount of the water-absorbing resin to the pulverization step)=(total discharge amount of the water-absorbing resin at the drying step)+(amount of the classified polymer supplied again to the same or a different pulverization step).

Abstract: The present invention relates to an absorbent suitable for use in a thin sanitary material/absorbent article having a high absorbent content and not prone to gel blocking, the absorbent having excellent liquid diffusibility (e.g. SFC) and minimal decrease in absorption ratio under pressure (e.g., AAP or PUP) even when a liquid permeation enhancer is added, and to a method for manufacturing the high-performance absorbent stably during actual production. The method is a method for manufacturing a polyacrylic acid (salt)-based absorbent, having a surface-crosslinking agent addition step for adding a solution of a surface-crosslinking agent, and a liquid permeation enhancer addition step for adding a liquid permeation enhancer, the liquid permeation enhancer addition step being performed after and/or at the same time as the surface-crosslinking agent addition step, the method characterized in that a surface crosslinking step for performing heat treatment in an atmosphere having a dew point of 45° C. to 100° C.

Abstract: The present invention provides a highly productive method for manufacturing a water-absorbing resin, the amounts of fine powder and dust of which are small, the amount of residual monomer of which is small, and whose absorption rate is high. That is, the method for manufacturing the water-absorbing resin of the present invention is a method for crosslinking and polymerizing an aqueous solution of an acid-group containing unsaturated monomer, and is characterized in that stationary polymerization is carried out in such a manner that a solid matter is added to the monomer aqueous solution, and an initiation temperature of the polymerization is adjusted to 40° C. or more or a maximum temperature of the polymerization is adjusted to 100° C. or more.

Abstract: An absorbent article that has a thin, conformable absorbent core where the core has at least two layers, both of which are substantially free of cellulosic fibers is described. The first layer is intended to provide storage for the majority of acquired fluids and has an AAP of at least about 20 g/g and the second layer, which provides temporary capacity for the bulk of the acquired fluid and permanent storage for at least a portion thereof, comprises a second absorbent polymer material which has a Wet Permeability of at least about 400×10?7 (cm3 seconds)/g a ratio of Wet Permeability to SFC of at least about 1.5:1 with respect to the first absorbent polymer material.

Abstract: The present invention provides a water absorbing agent that is excellent in a balance between a centrifugal retention capacity (CRC) and a saline flow conductivity (SFC), and a method for producing the water absorbing agent. The method for producing the water absorbing agent, the method comprising mixing (i) a water absorbing resin (A) and (ii) a polymer (B) being a polyamine polymer having a hydroxyl group on a main chain provides a water absorbing agent containing (i) the water absorbing resin (A) and (ii) the polymer (B) being a polyamine polymer having a hydroxyl group on a main chain.

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