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AssigneeNippon Shokubai Co., Ltd.
InventorsShigeru Yamaguchi, Yoshihiro Maeda, Tamao Ishida
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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.
A acrylic acid-maleic acid copolymer (or its salt), which is obtained by copolymerizing ethylenically unsaturated monomers including acrylic acid and maleic acid in the presence of a polymerization initiator, wherein the maleic acid has a neutralization degree of 70-95 mol % before the polymerization initiator is charged, and wherein the copolymer (or its salt) has a magnesium ion scavengeabilitiy of 230 mg (in terms of Mg(OH2)/g or more and a magnesium scale inhibitablity of 30% or more.
An acrylic acid-maleic acid copolymer (or its salt), which is obtained by copolymerizing ethylenically unsaturated monomers including acrylic acid and maleic acid in the presence of a polymerization initiator, wherein the maleic acid has a neutralization degree of 70-95 mol % before the polymerization initiator is charged, and wherein the copolymer (or its salt) has a magnesium ion scavengeability of 230 mg (in terms of Mg(OH)2 )/g or more, a molecular weight distribution of 3.5 or less, and low-molecular fractions with a molecular weight of 1,000 or less in the ratio of 9 wt % or less to the total of the copolymer (or its salt).
Dependencies are inferred from the claim text.