Improvements in and relating to the coating of paper

832,073. Mineral coated paper. KIMBERLEY-CLARK CORPORATION. Oct. 23, 1956, No. 32301/56. Class 96. A mineral coating mixture for high-grade printing paper, or barrier-coating greaseproof paper, is applied to the paper 10 as by rolls 14, 16, 12, and the surface of the coating is hardened by a liquid, e.g. a solution of aluminium sulphate, formaldehyde, ammonium sulphate, or other compounds of aluminium, copper, zinc, lead, iron, sodium, or calcium, applied by rolls 22, 21, so that the surface of the coating is hardened as the paper passes between e.g. a resilient roll 19, and a chromium-plated roll 21. The coating may include clay and/or calcium carbonate, casein, soya protein, glue, carboxy methyl-, hydroxy ethyl-, or oxidizedcellulose, polychloroprene, polyacrylic acid esters or other synthetic or natural rubber, polymers of vinyl acetate, copolymers of vinyl chloride and vinyl acetate or vinylidene chloride, sodium alginate, or a sodium salt of polystyrene-maleic anhydride. The binding media may be extended by starch or modified starch, and the coating may include plasticizers, softeners, sodium hexametaphosphate, wetting agents, and dyes.. The web may be coated on one or both sides, e.g. over other coatings.