| 摘要 |
PURPOSE: Provided are a polyaspartic acid polymer produced by using a compound having a phosphono group or a phosphoric acid group and a carboxyl acid group or a hydroxyl group in the molecule, which is excellent in scale inhibiting function and scale-formation delaying effect, and salts thereof. CONSTITUTION: The polyaspartic acid polymer is produced by a process comprising the steps of: 1) mixing 1mol of a dibasic acid and 0.1-10mol of the compound having the phosphono group or the phosphoric acid group and the carboxyl acid group or the hydroxyl group in water, wherein the compound is selected from amino trimethylene phosphonate(ATMP), 1-hydroxyethylidine-1,1-diphosphonate(HEDP), 2-phosphonobutane-1,2,4-tricarboxylate(PBTC), and etc.; 2) adding 0.5-2mol of ammonia to the mixture; 3) performing a polycondensation at 140deg.C under the vacuum of 10-140torr; increasing the temperature to be 160-240deg.C when the polymer of the 3 step changes brown. And the salts of the polyaspartic acid polymer are obtained by hydrolyzing the polyaspartic acid polymer with an alkali earth metal hydroxide, an alkali metal hydroxide, or ammonium hydroxide. |
