| 摘要 |
890,359. Electrostatic recording paper. WARREN CO., S. D. May 31, 1960 [June 22, 1957 ; Feb. 1, 1960], No. 19207/60. Class 96. Electrostatic recording paper is made with sufficient electrical conductance (e.g. its resistance measured across opposite sides of a square of the surface may be 10<SP>5</SP> to 10<SP>8</SP> ohms) as by inclusion of sodium or lithium chloride or carbon black with the pulp, or preferably, by impregnating a paper web, e.g. one made from bleached hard wood and coniferous wood pulp obtained by an alkaline pulping process, with a conductive resinous polymer, e.g. polyvinyl benzyl trimethyl ammonium chloride. Such paper is given a dielectric coating of e.g. 3 to 15 gms. per square metre, of a resinous copolymer e.g. of 95% vinyl acetate and 5% of crotonic acid. A surface application of starch and emulsified wax, or of mineral filler and adhesive and wax may precede the dielectric coating to reduce penetration into the paper. |
