ACRYLIC ACID-MALEIC ACID COPOLYMER (OR ITS SALT), ITS PRODUCTION PROCESS AND USE, AND PRODUCTION PROCESS FOR AQUEOUS MALEIC SALT SOLUTION WITH LOW IMPURITY CONTENT

摘要

The present invention provides: an acrylic acid-maleic acid copolymer (or its salt) which is excellent in performances, such as Mg2+ scavengeability, clay dispersibility in the presence of Mg2+, inhibitability upon Mg(OH)2 scale, and inhibitability upon CaCO3 scale; and a production process for such a copolymer (or its salt). The present invention further provides a production process for an aqueous maleic salt solution with a low impurity content which has the advantage of easily giving the above copolymer (or its salt). The present invention still further provides uses of the above copolymer (or its salt) having the above excellent properties.