Abstract: Disclosed are water-absorbent resin particles comprising a crosslinked polymer comprising a monomer unit derived from a water-soluble ethylenically unsaturated monomer, wherein an artificial menstrual blood volume increase rate as measured in an artificial menstrual blood swelling test conducted in the order of i), ii), and iii) is 70% or more. i) putting 1.0 g of water-absorbent resin particles into a measuring cylinder with an inner diameter of 27 mm. ii) injecting 10 ml of artificial menstrual blood into the cylinder at once to swell the water-absorbent resin particles. iii) measuring a volume (A) of the swollen water-absorbent resin particles after 60 seconds from the injection and calculating an artificial menstrual blood volume increase rate according to Equation (I) below. Artificial menstrual blood volume increase rate (%)=(A?B)/B×100 . . . (I), A . . . Volume (ml) of swollen water-absorbent resin particles, B . . . Volume (ml) of injected artificial menstrual blood.

Abstract: Disclosed are water-absorbent resin particles comprising a crosslinked polymer comprising a monomer unit derived from a water-soluble ethylenically unsaturated monomer, wherein an artificial menstrual blood volume increase rate as measured in an artificial menstrual blood swelling test conducted in the order of i), ii), and iii) is 70% or more. i) putting 1.0 g of water-absorbent resin particles into a measuring cylinder with an inner diameter of 27 mm. ii) injecting 10 ml of artificial menstrual blood into the cylinder at once to swell the water-absorbent resin particles. iii) measuring a volume (A) of the swollen water-absorbent resin particles after 60 seconds from the injection and calculating an artificial menstrual blood volume increase rate according to Equation (I) below. Artificial menstrual blood volume increase rate (%)=(A?B)/B×100 . . . (I), A . . . Volume (ml) of swollen water-absorbent resin particles, B . . . Volume (ml) of injected artificial menstrual blood.

Abstract: Disclosed are water-absorbent resin particles comprising a crosslinked polymer comprising a monomer unit derived from a water-soluble ethylenically unsaturated monomer, wherein an initial swelling force as measured according to a swelling force test conducted by a predetermined method is 8 N or more, and further, a ratio of the particles having a particle diameter of more than 250 ?m and 850 ?m or less is 70% by mass or more and a ratio of the particles having a particle diameter of 250 ?m or less is 20% by mass or less, with respect to the total amount of the water-absorbent resin particles.

Abstract: Water-absorbing resin particles are disposed, the water-absorbing resin particles including: a polymer particle containing a crosslinked polymer having a monomer unit derived from an ethylenically unsaturated monomer including at least one kind of compound selected from the group consisting of (meth)acrylic acid and a salt thereof; and a plurality of inorganic particles disposed on a surface of the polymer particle, in which a proportion of a (meth)acrylic acid and a salt thereof is 70 to 100 mol % with respect to a total amount of monomer units in the crosslinked polymer. In a case where a water absorption speed index I=(value of non-pressurization DW after 10 seconds)×6 [mL/g], and a water absorption speed index II=(value of non-pressurization DW after 3 minutes)/3 [mL/g], a static suction index ? calculated by the following formula: ?=(I+II)/2 is 5.0 mL/g or higher.

Abstract: Disclosed is a method for evaluating liquid leakage properties of water-absorbing resin particles. The method includes, in the following order: disposing a water-absorbing layer formed from the water-absorbing resin particles along an inclined plane inclined with respect to a horizontal plane; injecting a test solution which is in the form of liquid droplets and contains water into the water-absorbing layer exposed; and measuring a diffusion distance which is a distance in which the test solution injected into the water-absorbing layer diffuses along the inclined plane in a predetermined time. An angle of inclination formed by the horizontal plane and the inclined plane is 25 degrees or larger and 40 degrees or smaller.

Abstract: Water-absorbing resin particles, in which a permeation and spreading index represented by Formula (1) is 10.0 or higher, and a water absorption capacity for a physiological saline solution is 50.0 g/g or more, are disclosed.

Abstract: Provided is a method of producing a water-absorbent resin comprising a step of polymerizing a water-soluble ethylenically unsaturated monomer in the presence of an internal-crosslinking agent, and a step of performing post-crosslinking, wherein: the step of polymerizing comprises one or more polymerization steps; all the polymerization steps are performed in the presence of both one or more azo based compounds and peroxides so that the both are coexistent in the all steps; in each polymerization step, a proportion of the azo compounds is 40-95 mass % relative to an amount of the azo compounds and the peroxides; the water-absorbent resin has a water-absorption capacity of physiological saline under a load of 4.14 kPa at 120 minutes passed from the start of water absorption of 20 ml/g or more; and the degree of swelling under a load at 30 minutes is 70%.

Abstract: A method for manufacturing an absorbent body according to the present invention includes a first step of successively introducing an aggregate of absorbent fibers and a water-absorbent resin into a gap that is formed between a first surface and a second surface and is smaller than a thickness of the aggregate of the absorbent fibers, recesses and protrusions being formed on at least one of the first surface and the second surface, a second step of applying a shearing force to the aggregate of the absorbent fibers by moving the first surface relative to and parallel to the second surface in order to mix the absorbent fibers and the water-absorbent resin, and a third step of causing the absorbent fibers and the water-absorbent resin that were mixed to fall, and stacking the absorbent fibers and the water-absorbent resin by suctioning the absorbent fibers and the water-absorbent resin into a recessed portion having a predetermined shape.

Abstract: Provided is a water-absorbent resin that increases the diffusivity of a to-be-absorbed liquid and that makes it possible to effectively decrease the amount of re-wet. The water-absorbent resin is obtained by polymerizing a water-soluble ethylenicallyally unsaturated monomer under the presence of an internal-crosslinking agent, has the water-absorption capacity of physiological saline under a load of 4.14 kPa at 120 minutes passed from the start of water absorption of 20 ml/g or more, and exhibits the degree of swelling under a load at 30 minutes of 70% or less when the water-absorption capacity of physiological saline under a load of 4.14 kPa at 120 minutes from the start of water absorption is designated as the degree of swelling under a load of 100%.

Abstract: Disclosed are water-absorbent resin particles comprising a crosslinked polymer comprising a monomer unit derived from a water-soluble ethylenically unsaturated monomer, wherein an artificial menstrual blood volume increase rate as measured in an artificial menstrual blood swelling test conducted in the order of i), ii), and iii) is 70% or more. i) putting 1.0 g of water-absorbent resin particles into a measuring cylinder with an inner diameter of 27 mm. ii) injecting 10 ml of artificial menstrual blood into the cylinder at once to swell the water-absorbent resin particles. iii) measuring a volume (A) of the swollen water-absorbent resin particles after 60 seconds from the injection and calculating an artificial menstrual blood volume increase rate according to Equation (I) below. Artificial menstrual blood volume increase rate (%)=(A?B)/B×100 . . . (I), A . . . Volume (ml) of swollen water-absorbent resin particles, B . . . Volume (ml) of injected artificial menstrual blood.

Abstract: Disclosed are water-absorbent resin particles comprising a crosslinked polymer comprising a monomer unit derived from a water-soluble ethylenically unsaturated monomer, wherein an initial swelling force as measured according to a swelling force test conducted by a predetermined method is 8 N or more, and further, a ratio of the particles having a particle diameter of more than 250 ?m and 850 ?m or less is 70% by mass or more and a ratio of the particles having a particle diameter of 250 ?m or less is 20% by mass or less, with respect to the total amount of the water-absorbent resin particles.

Abstract: Provided is: a water-absorbent resin which has a better water absorption performance and with which it is possible to improve absorption performance under a load when used in an absorbent material. This water-absorbent resin, obtained by polymerising a water soluble ethylenically unsaturated monomer in the presence of an internal-crosslinking agent and by post-crosslinking using a post-crosslinking agent, has a water-absorption capacity of physiological saline under a load of 4.14 kPa of 16 mL/g or more, has a mass proportion of particles from 150 to 850 ?m relative to the whole proportion of 85 mass % or more, moreover has a mass proportion of particles from 300 to 400 ?m relative to the whole proportion of 20 mass % or more, and has an absorption capacity elasticity index represented by formula (I) of 68,000 or more. Absorption capacity elasticity index=storage elastic modulus [Pa]×centrifugal retention rate [g/g] . . . (I).

Abstract: Provided are: a water-absorbent resin which, when used as an absorbent material, retains a high water-absorption performance, increases the diffusivity of a to-be-absorbed liquid and makes it possible to effectively decrease the amount of re-wet; and an absorbent article formed using an absorbent material including the water-absorbent resin. The water-absorbent resin according to the present invention is a water-absorbent resin obtained by polymerizing a water-soluble ethylenically monomer in the presence of an internal-crosslinking agent and thereafter post-crosslinking the polymer with a post-crosslinking agent, characterized in that when subjected to a liquid flow test, the water-absorbent resin has an effective absorbent material index (K) indicated by equation (I) of 250 or greater.

Abstract: A method for manufacturing an absorbent body according to the present invention includes a first step of successively introducing an aggregate of absorbent fibers and a water-absorbent resin into a gap that is formed between a first surface and a second surface and is smaller than a thickness of the aggregate of the absorbent fibers, recesses and protrusions being formed on at least one of the first surface and the second surface, a second step of applying a shearing force to the aggregate of the absorbent fibers by moving the first surface relative to and parallel to the second surface in order to mix the absorbent fibers and the water-absorbent resin, and a third step of causing the absorbent fibers and the water-absorbent resin that were mixed to fall, and stacking the absorbent fibers and the water-absorbent resin by suctioning the absorbent fibers and the water-absorbent resin into a recessed portion having a predetermined shape.

Abstract: The following are provided: a water-absorbent resin in which, in the formation of an absorbent material forming an absorbent article, dispersion is satisfactory even in a moisture absorption state, which prevents the occurrence of troubles at the time of manufacturing of the absorbent article and which allows efficient manufacturing; and an absorbent article using an absorbent material containing the water-absorbent resin. The water-absorbent resin according to the present invention is obtained by polymerizing a water-soluble ethylenically unsaturated monomer and performing post-crosslinking thereon with a post-crosslinking agent, and the water-absorbent resin satisfies the requirements below: (A) yellow index is 5.0 or less; and (B) gel strength is 1800 Pa or less.

Abstract: Provided are a water-absorbent resin having better water-absorption performance and being prevented from discoloring before and after storage for a long time under high temperature and high humidity, and an absorbent article including the absorbent resin. The water-absorbent resin according to the present invention is prepared by polymerizing a water-soluble ethylenically unsaturated monomer in the presence of an internal-crosslinking agent and performing post-crosslinking with a post-crosslinking agent, wherein the water-absorbent resin satisfies the following properties: (A) a water-absorption capacity of physiological saline of 55 g/g or more, a water-absorption capacity of physiological saline under a load of 4.14 kPa of 15 mL/g or more, and a residual monomer content of 300 ppm or less; and (B) a yellow index of 5.0 or less and a yellow index change ratio (?YI) after leaving for 10 days under 70° C. and 90% RH of 10 or less.

Abstract: With respect to water-absorbent resins, there are provided a method of manufacturing a water-absorbent resin having an appropriate BET specific surface and a water-absorption rate and a water-absorbing agent and an absorbent article that are formed by using the water-absorbent resin. In a first aspect of the present invention, when reverse phase suspension polymerization of two steps or more is performed on a water-soluble ethylenically unsaturated monomer in a hydrocarbon dispersion medium in the presence of at least an azo compound, a peroxide and an internal-crosslinking agent, the used amount of the internal-crosslinking agent at the time of the polymerization of a first step is adjusted to fall within a range of 0.015 to 0.

Abstract: Provided are: a water-absorbent resin which, when used as an absorbent material, retains a high water-absorption performance, increases the diffusivity of a to-be-absorbed liquid and makes it possible to effectively decrease the amount of re-wet; and an absorbent article formed using an absorbent material including the water-absorbent resin. The water-absorbent resin according to the present invention is a water-absorbent resin obtained by polymerizing a water-soluble ethylenically monomer in the presence of an internal-crosslinking agent and thereafter post-crosslinking the polymer with a post-crosslinking agent, characterized in that when subjected to a liquid flow test, the water-absorbent resin has an effective absorbent material index (K) indicated by equation (I) of 250 or greater.

Abstract: Provided is a water-absorbent resin that increases the diffusivity of a to-be-absorbed liquid and that makes it possible to effectively decrease the amount of re-wet. The water-absorbent resin is obtained by polymerizing a water-soluble ethylenicallyally unsaturated monomer under the presence of an internal-crosslinking agent, has the water-absorption capacity of physiological saline under a load of 4.14 kPa at 120 minutes passed from the start of water absorption of 20 ml/g or more, and exhibits the degree of swelling under a load at 30 minutes of 70% or less when the water-absorption capacity of physiological saline under a load of 4.14 kPa at 120 minutes from the start of water absorption is designated as the degree of swelling under a load of 100%.

Abstract: Provided is: a water-absorbent resin which has a better water absorption performance and with which it is possible to improve absorption performance under a load when used in an absorbent material. This water-absorbent resin, obtained by polymerizing a water soluble ethylenically unsaturated monomer in the presence of an internal-crosslinking agent and by post-crosslinking using a post-crosslinking agent, has a water-absorption capacity of physiological saline under a load of 4.14 kPa of 16 mL/g or more, has a mass proportion of particles from 150 to 850 ?m relative to the whole proportion of 85 mass % or more, moreover has a mass proportion of particles from 300 to 400 ?m relative to the whole proportion of 20 mass % or more, and has an absorption capacity elasticity index represented by formula (I) of 68,000 or more. Absorption capacity elasticity index=storage elastic modulus [Pa]×centrifugal retention rate [g/g] . . .