Patent ID: 8912299
Filing Date: 2014-12-16
Classification: C04B,C08F

Abstract:
1. A preparation method of a star-shaped polycarboxylate superplasticizer, comprising an esterification step and a polymerization step in sequence, wherein: (1) the esterification step: polyol is added to a reactor and heated to a temperature of 40-80° C., and then a polymerization inhibitor, (meth)acrylic acid and catalyst are added to the reactor in turns with each interval of 5-20 minutes and constant stirring, heating is continued and a water-carrying agent is added when the temperature reaches 80-100° C., after continual heating to 100-150° C., esterification is carried out and, during the esterification, produced water is separated, after reaction for 2-10 hours, the water-carrying agent was removed by vacuum pumping, and an esterification product is obtained; (2) the polymerization step: the esterification product and water are added to the reactor and heated to a temperature of 50-65° C. and stirred for 10-30 minutes, and then unsaturated polyoxyethylene ether, molecular weight regulator, (meth)acrylic acid or its mixture with unsaturated carboxylic acids, and a persulfate solution with a mass concentration of 1-30% as initiator are added to the reactor in turns with each interval of 5-20 minutes and constant stirring, after continual heating to 65-90° C., polymerization is carried out, after reaction for 1.5-8 hours, the temperature is lowered to 40-60° C. and the product is neutralized by an alkaline solution with a mass concentration of 10-50% to adjust pH value to 6-8, after cooling to a temperature of 25-40° C., a solution of the star-shaped polycarboxylate superplasticizer with a desired concentration is finally obtained by mixing appropriate amount of water;