| 摘要 |
<p>PROBLEM TO BE SOLVED: To decrease viscosity of the system and to obtain a slurry of high density by hydrating magnesium oxide under the presence of a copolymer salt ofα,β-unsatd. dicarboxylic acid monomer and/or its anhydride and an ethylenically unsatd. monomer, thereby suppressing rapid heat generation by the hydration. SOLUTION: A salt of a copolymer described below is added by 0.01 to 5 pts.wt. to 100 pts.wt. of magnesium oxide, and magnesium oxide is mixed with water to carry out hydration to obtain a magnesium hydroxide slurry. The copolymer salt consists of a copolymer of 20 to 80 mol.%α,β-unsatd. dicarboxylic acid monomer and/or its anhydride and an ethylenically unsatd. monomer, preferably monoolefin monomer having 2 to 10 carbon atoms. The copolymer has 500 to 5000 number average mol.wt. and >=50 mol.% of the carboxyl groups in the molecule form alkali (earth) metal salts. The hydration is carried out at 5 to 90 deg.C with 30 to 60 wt.% magnesium oxide and 70 to 40 wt.% water (total 100 wt.%).</p> |
