| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively provide a water-absorbing resin free from an acid odor of acetic acid or propionic acid, without excessively refining acrylic acid of the raw material, even when using the acrylic acid containing 600 ppm or more of total amount of the acetic acid and the propionic acid.SOLUTION: This method for producing the polyacrylic acid (polyacrylate)-based water-absorbing resin includes: a process of preparing an aqueous monomer solution, using the acrylic acid containing 600 ppm or more of total amount of the acetic acid and the propionic acid; a polymerization process of the aqueous monomer solution; a drying process of drying an obtained water-containing gel-like crosslinked polymer; and a surface crosslinking process of surface-crosslinking the water-containing gel-like cross-linked polymer or a dried product thereof. An Fe content is 2 ppm or less with respect to a solid content amount in the aqueous monomer solution, the polymerization process comprises reversed phase suspension polymerization in a 6C-8C hydrophobic organic solvent using a persulfate as a polymerization initiator, in the presence of p-methoxy phenol and a surfactant, the drying process comprises the first drying process of carrying out azeotropic-dehydration in the hydrophobic organic solvent, and the second drying process of carrying out stirring or fluidization drying after the azeotropic dehydration, the second drying process is carried out after the surface crosslinking, and a water content is regulated within a range of 5-15 wt.%, in the method for producing the polyacrylic acid (polyacrylate)-based water-absorbing resin. |
