PREPARATION OF WATER-ABSORBING RESIN

摘要

PROBLEM TO BE SOLVED: To achieve excellent water absorption under atmospheric pressure or an elevated pressure and excellently small time-dependence of water absorption during operation by adding a chelating agent when recycling a gelled or fine polymer which generates in a preparation process of a water-absorbing resin. SOLUTION: This water-absorbing resin is required to have a carboxy group so that the resin absorbs a lot of water in water to form a hydrogel and such an example is a partially neutralized crosslinked polyacrylic acid or the like. A content of the carboxy group is not limited but is preferably not less than 0.01 equivalent per 100 g of the water-absorbing resin. The water-absorbing resin is preferably a resin on which an extremely small amount of an intra- crosslinking agent containing not less than 2 polymerizable unsaturated groups or not less than 2 reactive groups is made to copolymerize or react rather than a resin which is self-crosslinkable without use of a crosslinking agent. A chelating agent to be used is an aminocarboxylic acid or the like and the amount thereof is 0.0001-10 pts.wt. per 100 pts.wt. of a product to be recycled.