POLYACRYLIC ACID (SALT), POLYACRYLIC ACID (SALT)-BASED WATER-ABSORBING RESIN, AND PROCESS FOR PRODUCING SAME

摘要

Provided is a polyacrylic acid (salt), in particular, a polyacrylic acid (salt)-based water-absorbing resin, which contains a method tracer with which the steps which were used for producing the water-absorbing resin can be examined with respect to various troubles that can arise over the water-absorbing resin during the period from the steps for producing the water-absorbing resin to the use and discard thereof by a consumer. The polyacrylic acid (salt)-based water-absorbing resin has a stable carbon isotope ratio, as determined by accelerator mass spectrometry, of less than -20 0/00 and has a radioactive carbon content of 1.0×10-14 or more. The polyacrylic acid (salt)-based water-absorbing resin is characterized by satisfying the following properties (1) to (6): (1) a CRC of 10 [g/g] or more; (2) an AAP of 20 [g/g] or more; (3) an Ext of 35 wt.% or less; (4) a content of residual monomers of 1,000 ppm or less; (5) a PSD in which the proportion of particles having a particle diameter of 150 µm or larger but less than 850 µm is 90 wt.% or more; and (6) an FSR of 0.15 [g/g/s] or more.