| 摘要 |
PURPOSE:The titled copolymer having excellent ability to disperse inorganic pigments and an ability to chelate calcium ions, prepared by copolymerizing (meth) acrylic acid with a specified excess molar amount of maleic acid in an aqueous solution maintained at a specified pH. CONSTITUTION:A copolymer satisfying the relationships: r=1.15-2.7, MW= 1,000-8,000 and rXMW>=3,000, wherein r is a maleic acid/(meth)acrylic monomer mol ratio and MW is an average MW, is produced by copolymerizing materials consisting of (meth)acrylic acid and 1.2-1.3mol, per mol of (meth)acrylic acid, of maleic acid in an aqueous solution adjusted at a pH of 3.5-5.0 with an alkali metal hydroxide and, if necessary, neutralizing the resulting copolymer. In prior arts, a copolymer having a MW>=1,000 has not been obtained in case where said mol ratio exceeds 1, but it can be obtained by carrying out the copolymerization in an aqueous solution at an adjusted pH. This copolymer is useful as a calcium ion scavenger, especially a scale-preventing agent. |
