To obtain a water-swelling rubber containing a liquid-absorbing agent comprising the alkaline earth metal salt of a copolymer comprising an anionic monomer, etc., reduced in eluted components, high in the swelling ratio, excellent in durability and safety, and suitable as a water-stopping material for civil engineering works, etc.
This water-swelling rubber contains a liquid-absorbing agent comprising the alkaline earth metal (e.g. magnesium) salt of a copolymer introduced from monomer components comprising (A) an anionic monomer such as (meth)acrylic acrid and (B) a nonionic monomer of the formula [R is H, methyl; (X)n are 2-4C oxyalkylene units containing oxyethylene units in a mole fraction of ≥50mol.% based on the whole oxyalkylene units; Y is a 1-5C alkoxy, phenoxy, etc.; n is 3-100]. The liquid-absorbing ratio of the liquid-absorbing material for an artificial sea water is preferably ≥5g/g.
OKAMURA KAZUHIRO
SHIMOMURA TADAO
