US-12616618-B2 - Absorber with particles having water absorption and wettability properties

Abstract

One aspect of the present invention relates to an absorber containing water-absorbing resin particles, in which the water-absorbing resin particles include water-absorbing resin particles (A) which have a water absorption rate of 55 to 150 seconds according to a Vortex method and have a non-pressure DW 5-minute value of 36 mL/g or less, and the content of the water-absorbing resin particles (A) based on a total amount of the water-absorbing resin particles is 9 to 90 mass %.

Inventors

• Kazuyoshi Takamatsu
• Chiho ONITA

Assignees

• SUMITOMO SEIKA CHEMICALS CO., LTD.

Dates

Publication Date

20260505

Application Date

20210630

Priority Date

20200717

Claims (13)

1. 1 . An absorber comprising water-absorbing resin particles, wherein the water-absorbing resin particles comprise water-absorbing resin particles (A) that have a water absorption rate of 61 to 150 seconds according to a Vortex method and have a non-pressure DW 5-minute value of 36 mL/g or less, wherein the content of the water-absorbing resin particles (A) based on a total amount of the water-absorbing resin particles is 20 to 90 mass %, wherein the water-absorbing resin particles comprise water-absorbing resin particles (B) different from the water-absorbing resin particles (A), and wherein the water-absorbing resin particles (B) have a water absorption rate of less than 55 seconds according to a Vortex method and a non-pressure DW 5-minute value of more than 36 mL/g.
2. 2 . The absorber according to claim 1 , wherein the water-absorbing resin particles (A) are coated resin particles having a water-insoluble coating layer that covers at least a part of the surface of the water-absorbing resin particles.
3. 3 . The absorber according to claim 2 , wherein the coating layer is a layer comprising at least one water-insoluble component selected from among water-insoluble organic compounds and water-insoluble inorganic compounds.
4. 4 . The absorber according to claim 3 , wherein the water-insoluble organic compounds comprise at least one organic compound selected from the group consisting of polyurethanes, polyolefins, polyesters, polyamides, polystyrenes, polycarbonates, polyacrylates, polyacetals, and acid-modified products thereof.
5. 5 . The absorber according to claim 3 , wherein the water-insoluble inorganic compounds comprise at least one inorganic compound selected from the group consisting of light anhydrous silicic acid, calcium silicate, silicon dioxide, talc, silicon monoxide, and synthetic hydrotalcite.
6. 6 . The absorber according to claim 1 , wherein the water-absorbing resin particles (A) have a water absorption rate of 63 to 150 seconds according to a Vortex method and have a non-pressure DW 5-minute value of 36 mL/g or less.
7. 7 . The absorber according to claim 1 , wherein the water-absorbing resin particles (A) have a water absorption rate of 65 to 150 seconds according to a Vortex method and have a non-pressure DW 5-minute value of 36 mL/g or less.
8. 8 . The absorber according to claim 1 , wherein the water-absorbing resin particles (A) have a water absorption rate of 61 to 150 seconds according to a Vortex method and have a non-pressure DW 5-minute value of 1 mL/g or more and 36 mL/g or less.
9. 9 . The absorber according to claim 1 , wherein the water-absorbing resin particles (A) have a water absorption rate of 63 to 150 seconds according to a Vortex method and have a non-pressure DW 5-minute value of 1 mL/g or more and 36 mL/g or less.
10. 10 . The absorber according to claim 1 , wherein the water-absorbing resin particles (A) have a water absorption rate of 65 to 150 seconds according to a Vortex method and have a non-pressure DW 5-minute value of 1 mL/g or more and 36 mL/g or less.
11. 11 . The absorber according to claim 1 , wherein the water-absorbing resin particles comprise a crosslinked polymer formed by polymerization of monomers comprising ethylenically unsaturated monomers.
12. 12 . The absorber according to claim 11 , wherein the ethylenically unsaturated monomers comprise at least one compound selected from the group consisting of (meth)acrylic acid and salts thereof, acrylamide, methacrylamide, and N,N-dimethylacrylamide.
13. 13 . The absorber according to claim 11 , wherein the ethylenically unsaturated monomers comprise at least one compound selected from the group consisting of (meth)acrylic acid and salts thereof, and acrylamide.

Description

TECHNICAL FIELD The present invention relates to an absorber. BACKGROUND ART In the related art, as absorbing articles for absorbing a liquid containing water such as urine as a main component, absorbers containing water-absorbing resin particles are used. For example, Patent Literature 1 discloses a method of producing water-absorbing resin particles having a particle size suitable for use in absorbing articles such as diapers, and Patent Literature 2 discloses a method of using a hydrogel-forming absorbing polymer having specific saline flow inductivity, performance under pressure and the like as an absorbing member effective for accommodating an aqueous component solution. CITATION LIST Patent Literature [Patent Literature 1] JP H06-345819 A[Patent Literature 2] JP H09-510889 A SUMMARY OF INVENTION Technical Problem Regarding the performance required for an absorbing article, it is important that a liquid not easily leak even when the article is worn for a long time. As a method of minimizing liquid leakage, it is conceivable to use water-absorbing resin particles having a high water absorption rate (a large water retention capacity after water absorption) as a material constituting an absorber. However, water-absorbing resin particles having a high water absorption rate have poor liquid diffusibility, and as a result, liquid leakage from the absorbing article cannot be sufficiently minimized. Specifically, when water-absorbing resin particles swell with a liquid, gaps inherently present between water-absorbing resin particles are filled with swollen gel-like water-absorbing resin particles, which makes it difficult for the liquid to pass through the gaps. Such a phenomenon is generally referred to as a gel-blocking phenomenon. As a result, the diffusibility of the liquid in the absorber becomes low, the entire amount of water-absorbing resin particles contained in the absorber cannot be effectively used, and the liquid that has not been absorbed by the water-absorbing resin particles tends to leak from the absorber. In order to inhibit the gel-blocking phenomenon, when water-absorbing resin particles having a low water absorption rate (a small water retention capacity after water absorption) are used as a material constituting the absorber, the gel-blocking phenomenon hardly occurs, and the liquid easily diffuses in the absorber. However, when water-absorbing resin particles having a low water absorption rate are used, a rate (absorption rate) at which the absorber absorbs the liquid tends to be excessively low. In addition, in the water-absorbing resin particles having a low water absorption rate, re-wet (leakage of liquid that has been temporarily absorbed by the water-absorbing resin particles) tends to occur due to pressurization. An objective of the present invention is to provide an absorber having an excellent liquid diffusibility, a small re-wet amount, and a high absorption rate. Solution to Problem One aspect of the present invention is an absorber containing water-absorbing resin particles, in which the water-absorbing resin particles include water-absorbing resin particles (A) which have a water absorption rate of 55 to 150 seconds according to a Vortex method and have a non-pressure DW 5-minute value of 36 mL/g or less, and the content of the water-absorbing resin particles (A) based on a total amount of the water-absorbing resin particles is 9 to 90 mass %. Advantageous Effects of Invention According to the present invention, it is possible to provide an absorber having an excellent liquid diffusibility, a small re-wet amount, and a high absorption rate. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a cross-sectional view showing an example of an absorbing article. FIG. 2 is a schematic view showing a device for measuring a non-pressure DW of water-absorbing resin particles. DESCRIPTION OF EMBODIMENTS Hereinafter, several embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In this specification, “acryl” and “methacryl” are collectively referred to as “(meth)acryl.” Similarly, “acrylate” and “methacrylate” are denoted as “(meth)acrylate.” “(Poly)” means both with and without the “poly” prefix. In the numerical ranges stated stepwise in this specification, the upper limit value or the lower limit value of the numerical range of a certain stage can be arbitrarily combined with the upper limit value or the lower limit value of the numerical range in another stage. In the numerical ranges stated in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with values shown in examples. Materials exemplified in this specification may be used alone or two or more thereof may be used in combination. Unless otherwise specified, when there are a plurality of substances corresponding to components in the composition, the content of each component in the composition means