| 摘要 |
PROBLEM TO BE SOLVED: To provide a water cutoff material showing a stable swelling property for a long time. SOLUTION: This is a water cutoff material comprising a polyurethane, and this polyurethane foam is a polyurethane foam contg. oxyethylene groups and has a density of 0.3-0.9 g/cm2, a water swelling volume rate of 1.2-8 times, and both mass reduction rates of 7 days immersion in 70 deg.C water and 180 days immersion in 23 deg.C water being not higher than 3%, and this is a mold molding or a processed molding.
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