Copolymer latex as well as compositions and their application products containing it

In a composition comprising a filler, etc., sufficient adhesive strength can not be obtained as a binder, and a copolymer latex having a small particle size handling property is good at low viscosity, and Kaminuri Engineering composition using the copolymer latex things and coated paper having this by coating layer. Copolymer latex, (A) 20 to 80 wt% of structural units derived from an aliphatic conjugated diene monomer, (B) a structural unit derived from an unsaturated carboxylic acid monomer 4-15% by weight, and ( C) a structural unit derived from other copolymerizable monomer 5-76% by weight (however, (a) a, (B) and the sum of (C) is 100 wt%.) having a copolymer contain a number average particle diameter measured by transmission electron microscope 30 to 80 nm, viscosity of the solid content of 48 mass% is 50~400mPa · s.