To provide a copolymer latex for use in a composition for coating paperboard, which produces coated paperboard having largely improved surface strength and excellent water resistance, ink drying characteristics, printing glazing, suitability for blister pack and sizing, superior in operation efficiency in paper coating with improved prevention of surface tackiness.
This copolymer latex is obtained by copolymerizing (a) 20-80 wt.% aliphatic conjugated diene-based monomer, (b) 0.5-10 wt.% ethylenically unsaturated carboxylic acid monomer, and (c) 10-79.5 wt.% other monomer copolymerizable therewith, wherein the copolymer has at least two glass transition points in the range of -100 to 50°C and the difference between the maximum and the minimum glass transition point is not less than 5, and wherein the ζ(zeta) potential difference on the surface of the copolymer particle is from -100 to -10 mV.
ISHIKAWA OSAMU
ZAMA YOSHIAKI
TSURUOKA KATSUHIKO
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