PROBLEM TO BE SOLVED: To develop a novel water absorbing and decomposable resin having a high decomposition rate and excellent in environmentally friendly features such as photodegradability, biodegradability, or hydrolyzability. SOLUTION: An aliphatic polyester crosslinked water absorbing polymer (V) is a water absorbing polymer manufactured through polymerization of a hydrophilic acrylic monomer (IV) by using an aliphatic polyester crosslinking agent (III) as a crosslinking agent. The crosslinking agent (III) comprises at least one 2-10C linear aliphatic polybasic acid and at least one 2-6C linear aliphatic polyhydric alcohol. In a molecule of the crosslinking agent (III), water- soluble polymerizable unsaturated carboxylic acids (II) are bonded by esterification with hydroxyl groups of a linear aliphatic polyhydric alcohol ester (I) having two or more hydroxyl groups and two or more ester bonds. COPYRIGHT: (C)2003,JPO
