PREPARATION METHOD OF STYRENE-BUTADIENE COPOLYMER LATEX FOR PREPARATION OF MODIFIED CONCRETE

摘要

PURPOSE: A method for preparing a styrene-butadiene copolymer latex for the preparation of the modified concrete is provided to improve workability, strength, water resistance and durability of concrete. CONSTITUTION: The method comprises the steps of (i) adding 5-9 parts by weight of a butadiene monomer, 10-14 parts by weight of a styrene monomer, 0.4-0.8 parts by weight of rosin salt as an emulsifier, 0.5-0.7 parts by weight of potassium hydroxide, 0.7-1.0 parts by weight of t-decylmercaptan, 0.7-1.0 parts by weight of potassium sulfate and 0.3-1.0 parts by weight of sodium bisulfate to initiate the polymerization at 55 deg.C; and (ii) adding 26-30 parts by weight of a butadiene monomer, 50-54 parts by weight of a styrene monomer, 0.5-1.0 parts by weight of rosin salt as an emulsifier, 4.0-10.0 parts by weight of a polyoxyethylene alkyl ether-based nonionic emulsifier and 0.8-1.2 parts by weight of t-decylmercaptan, increasing the temperature to 60 deg.C at the conversion rate of 40-50%, increasing the temperature to 65 deg.C at the conversion rate of 60-70%, and increasing the temperature to 70 deg.C at the conversion rate of 80-90% to terminate the reaction.