Verfahren zur Herstellung temperaturempfindlicher Registrierpapiere

摘要

868,579. Temperature-sensitive recording- paper; temperature-sensitive paper. PERMACO S.A. Sept. 15, 1959 [Sept. 16, 1958; June 12, 1959 (2)], No. 31458/59. Classes 96 and 140. A temperature-sensitive recording paper having a light-coloured coating layer applied to a dark carrier paper is produced by coating paper with a solution of a solid, highly polymerized organic substance in a low-boiling organic solvent mixed with a higher-boiling organic liquid, which is inert towards the paper and in which the highly-polymerized organic substance is insoluble, the total mixture having a solid content of 6 to 20% by weight and the highly-polymerized organic substance being not precipitated, the low-boiling organic solvent and the high-boiling organic liquid being subsequently evaporated from the coating. The low-boiling organic solvent may be acetone, methyl acetate, tetrahydrofurane, dimethylacetal or methylene chloride, the higher-boiling organic liquid may be cyclohexane, hexane, heptane or benzine, and the solid, highly-polymerized organic substance may be a cellulose ester or ether, polystyrene, polyvinyl acetate, a ketone resin, a derivative of colophony, a phenol - formaldehyde resin, polyvinylidene chloride, polyvinyl chloride, polymethacrylate or a coumarone resin. Again, the low-boiling organic solvent may be pentane, hexane or benzine, the higher-boiling organic liquid may be ethyl acetate or methyl ethyl ketone and the solid, highly polymerized organic substance may be polyisobutylene. A low melting-point resin or wax or softener may be added to the highlypolymerized organic substance for reducing the melting temperature of the coating layer. To evaporate the low-boiling organic solvent, a current of air at a temperature of 20‹ to 40‹ C. may be directed on to the surface of the coating layer until it is whitened, a current of air at a temperature of 40‹ to 100‹ C. being subsequently used to evaporate the higher-boiling organic liquid. An optical brightener which is insoluble in the higher boiling organic liquid and may be a derivative of benzthiazole, stilbene or triazine as in Specification 683,895, may be dissolved in the coating solution. Again, the coating may contain substances such as peroxides and reducing agents, peroxy acids or acid peroxides and bases having a reducing action, e.g. amines, or acids and bases, which react together at a temperature above their melting-point with evolution of heat, and which are insoluble in the higher-boiling organic liquid.