| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a copolymer latex that can realize a sufficient strength and yet that is hard for a coagulum to adhere.SOLUTION: The copolymer latex is a copolymer latex produced by emulsion polymerization and the copolymer is composed of a monomer component consisting of 15 to 60 mass% of aliphatic conjugated diene monomer, 5 to 35 mass% of ethylenic unsaturated carboxylic acid monomer, 0.5 to 30 mass% of vinyl cyanide monomer, and 0 to 79.5 mass% of monomer co-polymerizable therewith, and the emulsion polymerization is carried out in such a way in which more than 0 mass% to 40 mass% or less of the total amount of the ethylenic unsaturated carboxylic acid monomer is contained in the reaction system at the polymerization initiator inputting-starting time point, and the addition of the remainder of the ethylenic unsaturated carboxylic acid monomer is started after 5% of the time duration from the reaching time point when the polymer conversion percentage of the reaction system has reached 1.0%, to the finishing time point when the inputting of the total amount of the monomer component has finished, has passed, and 92 mass% or more of the total amount of the ethylenic unsaturated carboxylic acid monomer is input before 80% of the time duration from said reaching time point to said finishing time point has passed, and the copolymer latex has a ratio, A/B, between the total acid group amount A per 100 g of solid of the copolymer latex measured by a neutralization titration method (milliequivalent/100 g) and the total acid group amount B per 100 g of solid of the copolymer latex calculated based on the blended amount of the acid component (milliequivalent/100 g), of 0.8 or less.</p> |
