Sumitomo Seika Chemicals Co., Ltd.

Hiroki Yabuguchi

Hideki Yokoyama

Tetsuhiro Hinayama

Masahiro Murakami

Masayoshi Handa

Yuichi Onoda

Kenji Tanimura

Maoki Hama

Hiromi Miyashita

Misaki Taniguchi

Toru Kawahara

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 α calculated by the following formula:α=()/2is 5.0 mL/g or higher.

Absorbent resin particles, absorbent article and production method therefor

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.Formula (1):Permeation and spreading index=value of non-pressurizationafter 1 minute (mL/g)+artificial urine permeation speed when water-absorbing resin particles are swollen 10 times (g/min)  (1).

Water-absorbent resin particles, water-absorbent article, and method for manufacturing same

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&#x2212;B)/B&#xd7;100 . . . (I), A . . . Volume (ml) of swollen water-absorbent resin particles, B . . . Volume (ml) of injected artificial menstrual blood.

Water-absorbent resin particle

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 &#x3bc;m and 850 &#x3bc;m or less is 70% by mass or more and a ratio of the particles having a particle diameter of 250 &#x3bc;m or less is 20% by mass or less, with respect to the total amount of the water-absorbent resin particles.

Water-absorbent resin particles

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:

Water-absorbent resin and method of producing water-absorbent resin

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.

Manufacturing method for absorbing body

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 &#x3bc;m relative to the whole proportion of 85 mass % or more, moreover has a mass proportion of particles from 300 to 400 &#x3bc;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]&#xd7;centrifugal retention rate [g/g] . . . (I).

Water-absorbent resin and absorbent article

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.Effective absorbent material index ()=[(the amount of liquid flow) (g)]&#xd7;[(artificial-urine absorption ratio) (g/g)]&#x2003;&#x2003;(I)

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:

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 (&#x394;YI) after leaving for 10 days under 70&#xb0; C. and 90% RH of 10 or less.

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 0.150 mmol per mole of the water-soluble ethylenically unsaturated monomer used at the time of the polymerization of the first step and he polymerization is performed such that, the BET specific surface area of secondary particles formed by agglomeration of primary particles obtained is controlled.

Method of manufacturing water-absorbent resin, water-absorbent resin, water-absorbing agent and absorbent article

There is disclosed a method for producing water-absorbent resin particles comprising a step that includes reversed-phase suspension polymerization of a water-soluble ethylenically unsaturated monomer in a suspension containing a surfactant that comprises a surfactant that comprises a fatty acid ester of sorbitan or sorbitol, or derivative thereof, and a hydrocarbon dispersion medium. The fatty acid ester includes a lauric acid ester and at least one kind of other ester selected from the group consisting of palmitic acid esters, stearic acid esters and behenic acid esters. The proportion of the peak area for lauric acid ester is 30-60%, based on the total peak area for fatty acid esters in the GPC chromatogram obtained from the fatty acid esters, and the proportion of the total peak area for other ester is 10-50%.

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Himeji, Japan

Hiroki Yabuguchi