Water-absorbing agent and its production process and use

A water-absorbing agent, having an absorption capacity of 30 (g/g) or more under no load and a dynamic deterioration absorption capacity of 20 (g/g) or more under a load, wherein the dynamic deterioration absorption capacity under a load is an absorption capacity of the water-absorbing agent as determined by the following sequential steps of:

• swelling a water-absorbing agent to 15 (g/g) with a physiological sodium chloride solution containing L-ascorbic acid in a concentration of 0.005 weight %;
• leaving the water-absorbing agent in such a swollen state for 4 hours;
• dynamically damaging the swollen water-absorbing agent;
• allowing the dynamically damaged water-absorbing agent to absorb the physiological sodium chloride solution for another 1 hour in a state where a load of 50 g/cm2 is mounted on the swollen water-absorbing agent;
• and
• measuring the weight of the resultant swollen gel.

A water-absorbing agent, having an absorption capacity of 30 (g/g) or more under no load and static deterioration absorption capacity (4) of 30 (g/g) or more under a load, wherein static deterioration absorption capacity (4) under a load is an absorption capacity of the water-absorbing agent as determined by the following sequential steps of:

• swelling a water-absorbing agent to 15 (g/g) with a physiological sodium chloride solution containing L-ascorbic acid in a concentration of 0.05 weight %;
• leaving the water-absorbing agent in such a swollen state for 6 hours;
• allowing the swollen water-absorbing agent to absorb the physiological sodium chloride solution for another 1 hour in a state where a load of 20 g/cm2 is mounted on the swollen water-absorbing agent;
• and
• measuring the weight of the resultant swollen gel.

A water-absorbing agent, obtained by a process including the step of adding to a water-absorbent resin at least one chelating agent selected from the group consisting of compounds of general formulae (1) and (2) and maleic hydrophilic polymers (including salts) (3),

• wherein general formula (1) is:
• 9
• wherein:
• n, X1, and R1˜R3 denote the following numbers and structures:
• 10
• and wherein general formula (2) is:
• 11
• wherein:
• m, X2, and R5˜R8 denote the following numbers and structures:
• 12