Patent ID: 9550843
Date: 2017-01-24
CPC Classifications: C08F,C08J

Claim:
1. A method for producing polyacrylic acid (salt)-based water absorbent resin, the method comprising, in order, a step in which an acrylic acid (salt)-based monomer aqueous solution is polymerized, a step in which the water-containing gel-like crosslinked polymer obtained in the polymerization step is dried, a step in which the dried polymer obtained in the drying step is pulverized, and a classification step which takes place after the drying step or after the pulverizing step, wherein, at the time of providing the dried polymer to a roll mill used in the pulverizing step, the dried polymer is provided in a dispersed state in the axial direction of a roll of the roll mill; and wherein an apparatus used for the pulverizing step comprises a pipe for supplying the dried polymer to the roll mill, and a length of the roll of the roll mill is 2 to 100 times the pipe diameter, and when said pipe is an angular pipe, said length of the roll of the roll mill is 2 to 100 time an inner width of the angular pipe.