Polyacrylic acid (salt), polyacrylic acid (salt) -based water-absorbing resin and its manufacturing method

The present invention provides a polyacrylic acid (salt) comprising the tracer method, in particular a polyacrylic acid (salt) -based water-absorbing resin, the water-absorbent resin from the manufacturing process for the consumer to use, may be discarded in the process the problems of water-absorbent resin produced by the method tracer test can be traced to the manufacturing process of the original water-absorbent resin. Polyacrylic acid of the invention (salt) -based water-absorbing resin ratio (δ13C) and less than -20 ‰ more radiocarbon is 1.0 × 10-14 or more determined by isotopic carbon accelerator mass spectrometry, characterized in that further satisfies the following (1) - properties predetermined (6): (1) CRC is 10 [g / g] or more, (2) AAP of 20 [g / g] or more, (3) Ext 35% by weight or less, (4 ) Residual? Monomer? s is 1000ppm or less, (5) The particle size was measured PSD 150μm or more, 850 m particles account for less than 90% by weight. (6) FSR of 0.15 [g / g / s] or more.