METHOD OF OBTAINING A COATING COMPOSITION FOR COATED PAPER Russian patent published in 2020 - IPC C08K13/00 B82B3/00 B82Y40/00 D21H19/40 

FIELD: technological processes; paper industry.

SUBSTANCE: invention relates to a method of producing a coating composition for coated paper. Method involves mixing a modified product and a modified binder. Modified product is obtained by mixing an aqueous dispersion of nanofibrillar cellulose with a pigment which is a mixture of calcium carbonate and kaolin with calcium carbonate content of 30–50 wt% with a dispersant and an antifoaming agent. Modified binder is obtained by mixing the binder with an aqueous suspension of nanofibrillar cellulose. Coating composition is obtained by mixing modified product with modified binder, having the following composition in terms of dry weight, wt%: pigment 69.0–76.7; binder 7.0–14.0; dispersant 0.5–1.5; antifoaming agent – 0.3–0.9; nanofibrillar cellulose – balance up to 100. When producing the modified product and modified binder, nanofibrillar cellulose is used with zeta potential from minus 36 mV to minus 200 mV in amount of 9.0–12.5 % and 3.0–6.5 % of the total weight of the coating composition in calculation on dry weight.

EFFECT: invention increases sedimentation resistance of the coating composition, increases adhesion of the coating composition to paper, regulates water retention of the coating composition; paper obtained using the coating composition has improved mechanical and printing-technical properties.

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