| 摘要 |
PROBLEM TO BE SOLVED: To provide low-mol.-wt. polyaspartic acid and its alkali metal salt and to provide the use of polyaspartic acid and its alkali metal salt as a detergent builder and a humectant. SOLUTION: The objective alkali metal salt of polyaspartic acid is prepared by the alkali hydrolysis of polyasparic anhydride which is prepared by the polycondensation of aspartic acid in the presence of an aliphatic dicarboxylic acid and/or an aliphatic dicarboxylic anhydride. The objective polyaspartic acid is prepared by adding an acid to the alkali metal salt. In both the polyaspartic acid and its alkali metal salt, 0.2-20% of the terminal structural units are ones derived from the aliphatic dicarboxylic acid and/or the aliphatic dicarboxylic anhydride. The polyaspartic acid and its alkali metal salt have each a wt. average mol.wt. of 1,000-80,000.
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