| 摘要 |
PURPOSE:To eliminate the lowering in water absorbing capacity with the elapse of time, by preparing a salt resistant water absorbent by polymerizing a specific amount of a specific sulfoalkyl methacrylate monomer, a methacrylamide monomer and a methacrylic acid monomer. CONSTITUTION:A mixture of 35-95mol% of a sulfoalkyl methacrylate monomer represented by formula I (wherein R<1> is hydrogen or a methyl group, R<2> is a 2-4C alkylene group and X is hydrogen, an alkali metal or an ammonium group), 10-25mol% of methacrylamide monomer represented by formula II (wherein R<3>, R<4> and R<5> are hydrogen or a methyl group) and 0-40mol% of a methacrylic acid monomer represented by formula III (wherein R<6> is hydrogen or a methyl group and Y is hydrogen, an alkali metal or an ammonium group) is polymerized in the presence of a crosslinking agent. A salt resistant water absorbent is prepared from this crosslinked polymer. |
