Water-absorbent sheet structure
A water-absorbent sheet structure comprises a structure in which an absorbent layer containing a water-absorbent resin (A) and a water-absorbent resin (B) is sandwiched with fibrous webs from an upper side and a lower side of the absorbent layer, characterized in that the water-absorbent resin (A) and the water-absorbent resin (B) are contained in a total amount of from 100 to 1,000 g/m 2 , and that the water-absorbent resin (A) and the water-absorbent resin (B) have the following properties: (1) the water-absorbent resin (A) having a water-retention capacity of saline solution (Ra) from 15 to 55 g/g; (2) the water-absorbent resin (B) having a water-retention capacity of saline solution (Rb) from 10 to 50 g/g; and (3) Ra and Rb mentioned above satisfies the relationship of the following formula: Ra−Rb≧(g/g). The water-absorbent sheet structure of the present invention exhibits some effects that a water-absorbent sheet structure has excellent shape retaining ability even when the structure is thin, so that the water-absorbent sheet structure does not undergo deformation of the form before liquid absorption or after the absorption, and is capable of sufficiently exhibiting absorbent properties.
1. A water-absorbent sheet structure comprising a structure in which an absorbent layer comprising a water-absorbent resin composition comprising a water-absorbent resin (A) and a water-absorbent resin (B) is sandwiched with fibrous webs from an upper side and a lower side of the absorbent layer, wherein the water-absorbent resin (A) and the water-absorbent resin (B) are contained in a total amount of from 100 to 1,000 g/m 2 , and that the water-absorbent resin (A) and the water-absorbent resin (B) have the following properties:
(1) the water-absorbent resin (A) having a water-retention capacity of saline solution (Ra) from 25 to 55 g/g;
(2) the water-absorbent resin (B) having a water-retention capacity of saline solution (Rb) from 20 to 24 g/g; and
(3) Ra and Rb satisfy the relationship: Ra−Rb≧5 (g/g)
wherein the water-absorbent resin (A) and the water-absorbent resin (B) are in a mass ratio, the water-absorbent resin (A): the water-absorbent resin (B), of from 90:10 to 80:20.
2. The water-absorbent sheet structure of claim 1 , wherein the water-absorbent resin (B) has a water-absorption capacity of saline solution under load of 4.14 kPa of 15 mL/g or more.
3. The water-absorbent sheet structure of claim 1 , wherein the fibrous webs are nonwoven fabrics comprising at least one fiber selected from the group consisting of rayon fibers, polyolefin fibers, and polyester fibers.
4. The water-absorbent sheet structure of claim 1 , wherein the water-absorbent sheet structure satisfies properties (4) to (6):
(4) a thickness of 5 mm or less, in a dry state;
(5) a total permeation rate of 120 seconds or less; and
(6) a leakage index of 150 or less.
5. An absorbent article, comprising:
the water-absorbent sheet structure of claim 1 , sandwiched between a liquid-permeable sheet and a liquid-impermeable sheet.
6. The water-absorbent sheet of claim 1 , wherein the water-absorbent resin (A) and the water-absorbent resin (B) are contained in a total amount of from 150 to 800 g/m 2 .
7. The water-absorbent sheet of claim 1 , wherein the water-absorbent resin (A) and the water-absorbent resin (B) are contained in a total amount of from 200 to 700 g/m 2 .
8. The water-absorbent sheet of claim 1 , wherein the water-absorbent resin (A) and the water-absorbent resin (B) are contained in a total amount of from 220 to 600 g/m 2 .
9. The water-absorbent sheet of claim 1 , wherein the water-absorbent resin (A) has a water-retention capacity of saline solution (Ra) of from 20 to 55 g/g.
10. The water-absorbent sheet of claim 1 , wherein the water-absorbent resin (A) has a water-retention capacity of saline solution (Ra) of from 25 to 55 g/g.
11. The water-absorbent sheet of claim 1 , wherein the water-absorbent resin (A) has a water-retention capacity of saline solution (Ra) of from 30 to 50 g/g.
12. The water-absorbent sheet structure of claim 1 , wherein the water-absorbent resin (B) has a water-absorption capacity of saline solution under load of 4.14 kPa of from 20 to 40 ml/g.
13. The water-absorbent sheet structure of claim 1 , said the water-absorbent resin composition consists of a water-absorbent resin (A), a water-absorbent resin (B) and an adhesive.