| abstract |
Provided are a water-absorbent resin having excellent absorption performance for saline, a water-repellent material comprising the water-absorbing resin, and a method for manufacturing the water absorbent resin. The water-absorbing resin of the present invention contains partially neutralized polyacrylic acid, the polyacrylic acid has a crosslinked structure, and the swelling height with respect to 3.3% by mass saline measured under the following measurement conditions is 3.5 mm/0.5 g or more. (Conditions for measurement of saline swelling height) 0.5 g of water absorbent resin particles are sprayed into a concave circular cup having a height of 30 mm and an inner diameter of 80.5 mm, a nonwoven fabric is laid thereon, and a convex circular cylinder having an outer diameter of 80 mm on the nonwoven fabric to be mounted. 55 g of 3.3 mass % saline at 20 degreeC is thrown in in the said concave circular cup. One minute after counting from the moment when the water-absorbent resin particles started to absorb, the distance at which the water-absorbent resin particles swell and push up the convex circular cylinder is measured, and this measured value is taken as the saline swelling height of the water-absorbent resin. |