METHOD OF PRODUCTION OF CARDBOARD WITH WHITE COVER LAYER Russian patent published in 2013 - IPC D21H21/02 D21H17/45 D21H17/68 D21H23/14 

FIELD: textiles, paper.

SUBSTANCE: method includes preparation of the first paper pulp from dispersion of paper fibers milled to the required fineness of grind by adding to it of cationic polyacrylamide, a second paper pulp from dispersion of mixture of bleached hardwood pulp, milled to the required fineness of grind, with a small amount of bleached softwood pulp by adding to the dispersion of bentonite 10-20 kg per ton of dry fiber, and then the suspension of mixture of talc and chalk in the amount of 50-200 kg per ton of fiber, and then the emulsion of alkenyl succinic anhydride stabilised with starch. Cationic polyacrylamide is added the last. The suspension of chalk and talc is prepared in a mixer under conditions providing intensive abrasing effect of chalk particles on talc particles. Talc contains at least 80% of particles with a size of 5-50 mcm and not less than 70% of particles with a size of 5-30 mcm.

EFFECT: improvement of the method.

4 cl, 1 tbl, 3 ex