Loading patent…
AssigneeNippon Shokubai Co., Ltd.
InventorsShigeru Yamaguchi, Shorbu Shioji, Yoshio Irie, Teruaki Fujiwara
Estimating the term…
The present invention relates to a process for producing an acid-type polymaleic acid and acid-type maleic acid copolymer and also to the usage of the acid-type polymaleic acid and acid-type maleic acid copolymer produced by this process. According to the process of the present invention, the acid-type polymaleic acid and acid-type maleic acid copolymer, which are superior as a water-treating agent and detergent additive, are produced by polymerization of acid-type monomers in an aqueous solution. The process is simple and yields a polymer having a low molecular weight and a narrow molecular-weight distribution. The process permits one to economically produce the acid-type polymaleic acid and acid-type maleic acid copolymer which has good quality and outstanding performance as a water-treating agent etc. Thus the invention is a great boon to the industrial field of water treatment.
A process for producing an acid-type maleic acid polymer having a number-average molecular weight of 300-5000 and a D-value (defined below) smaller than 2.0, said process comprising polymerizing a monomer component composed of maleic acid (A) alone or a monomer component composed of 50-99.9 wt % maleic acid (A) and 50-0.1 wt % other water-soluble unsaturated monomer (B), without neutralization, using water as the polymerization solvent, in the presence of at least one metal ion selected from the group consisting of iron ion, vanadium atom-containing ion, and copper ion in an amount of 0.5-500 ppm of said monomer component, by the aid of hydrogen peroxide as the polymerization catalyst in an amount of 8-100 g per mol of said monomer,
Dependencies are inferred from the claim text.