Przemysl Chemiczny, Vol.82, No.8-9, 1174-1176, 2003
The coating thickness effect on the migration extent of hydrophilic hinders in paper coatings
Aq. 70% (by weight) precipitated CaCO3 dispersion containing 0.3 pph BASF's Polysalz S dispersant, a butadiene-styrene latex (BSL), and an aq. 10% poly(vinyl alcohol) (PVA), was diluted with H2O to yield aq. 30% (by volume) mixtures M1(and M2): CaCO3 + 5 pph BSL + 4 (or 2) pph PVA. Paper wet-coated 24 (P3), 50 (P5) or 100 (P8) mum thick with Mayer's bar No. 3, 5, or 8, IR-dried, calendered (3.14 MPa), and stored at 65 +/- 2% r.h., yielded M1 and M2 coatings 7.8-47.8 and 4.2-42.0 mum thick. Coatings P8 resisted most to penetration of H2O and showed the highest dry pick resistance. Migration of hydrophilic binders through a wet consolidating coatings, which controls paper printing properties, was most effective in the thickest coat and the distribution of the binders in the dry coatings was uniform.