| 摘要 |
PURPOSE:A water swellable resin, consisting of a mixture of the conventional anionic water swellable resin with a specific polyurethane based resin having a specific block structure and a hydrophobic rubber base material and having sufficient water swelling properties regardless of the change in properties of water. CONSTITUTION:A water swellable resin obtained by incorporating (A) 100pts.wt. water swellable resin prepared by mixing (i) an A-B-A type block copolymer having at least one structure expressed by the formula (A is hydrophobic chain having 1,000-20,000 molecular weight; B is polyoxyethylene chain haivng 1,000-20,000 molecular weight or polyoxypropylene chain containing >=50wt% oxyethylene groups; Y is diisocyanate compound) and 3,000-60,000 molecular weight with (ii) an anionic water swellable resin, preferably a block copolymer having the bond type of (hydrophobic polymer segment)-(hydrophilic polymer segment)-(hydrophobic polymer segment) as 10-90:90-10 weight ratio of the components (i) to (ii) with (B) 20-2,000pts.wt. hydrophobic rubber base material.
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