| abstract |
PROBLEM TO BE SOLVED: To provide a copolymer latex for a paper coating composition containing high calcium carbonate, which is excellent in coating operability and printing paper strength. SOLUTION: A copolymer latex used as a binder in a paper coating composition containing 90% by weight or more of calcium carbonate in 100% by weight of the total pigment, and 35 to 65% by weight of an aliphatic conjugated diene monomer. %, 10 to 40% by weight of vinyl cyanide monomer, 4.5 to 10% by weight of ethylenically unsaturated carboxylic acid monomer and 0 to 50.5% by weight of other monomers copolymerizable therewith ( A copolymer latex obtained by emulsion polymerization of a total of 100% by weight of the monomers, and the weight ratio of monobasic acid and dibasic acid as the ethylenically unsaturated carboxylic acid monomer (1 base acid / 2 base acid) Is in the range of 0.01 to less than 0.5, and the number average particle diameter is 60 to 150 nm. [Selection figure] None |