GB1072303A - Printing paper - Google Patents

Abstract

High quality printing paper is prepared by applying 1 to 2 rounds of solid per side per ream of a coating material which is an aqueous slurry containing from substantially 15% to substantially 50% solids made up of a pigment and a binder, the pigment being at least 70% satin white, the pigment to binder weight ratio being from substantially 100:15 to substantially 100:50 partially drying to moisture content of substantially 6% to substantially 12%, applying with a doctor blade to the first coating on substantially 0.5 to substantially 1.5 pounds of solids per side per ream of a top coating material which is an aqueous slurry containing substantially 30% to substantially 60% solids made up of a pigment having at least 80% of platelet strucand a binder, the pigment binder weight ratio being from substantially 100:15 to substantially 100:50, partially varying the top coating to a moisture content of substantially 6% to substantially 12% and lightly finishing at a pressure of 300-500 pounds per linear inch. The satin white of the first coating can be used with other mineral pigments such as coating clay, calcium carbonate and TiO2. The binder in the first coat may be starch, enzyme-oxidized starch and other modified starches, casein, styrene-butadiene latex, polyvinyl acetal latex "Saran" (R.T.M.) latex, acrylic latex, and polyvinyl alcohol. The first coat may be applied by doctor blade coated, roll coated or trailing, blade coated. After partially drying the first coating the paper may be calendered at 100-900 pounds per linear inch pressure. The pigments of the second coating are coating clay or talc, and the binder may be as before.