| 摘要 |
PROBLEM TO BE SOLVED: To obtain a water-absorbing resin being excellent in a water absorption ratio, a water absorption rate, absorbing force, gel strength, etc., being excellent in a balance among these properties and reduced in the elution, of water-soluble components by crosslinking the surface of a specified polymer powder. SOLUTION: A water-containing gel-like polymer obtained by polymerizing a water-soluble ethylenically unsaturated monomer being an anionic monomer (e.g. acrylic acid, methacrylic acid or vinylsulfonic acid), a salt thereof, a nonionic hydrophilic-group-containing monomer (e.g. (meth)acrylamide or 2- hydroxyethyl (meth)acrylate), a cationic monomer (e.g. N,N-dimethylaminoethyl (meth)acrylate) or a quaternized product thereof in an aqueous solution is dried, ground and classified to obtain a polymer powder having a mean-particle diameter of 100-600μm, a particle size distribution having a logarithmic standard dcviationσζof 0.35 or below and a water content of below 10wt.%. This powder is mixed with a crosslinking agent and heated to 49-250 deg.C to crosslink the surface of the powder. The obtained water-absorbing resin is desirable for e.g. sanitary materials. |
