| 摘要 |
460,405. Security paper. CLAYTON, C. E. EVERY-. (Schoeller & Bausch, F.) May 20, 1936, No. 14325. [Class 96] To pulp or paper is added an inorganic salt giving a colour reaction to mild reducing agents e.g. sulphites ; substances giving colour reactions with oxidizing agents may also be used. The substances may be sprayed, painted, printed &c. on to paper. In examples, mercury-I-tungstate is precipitated on, or manganous tellurite is added to, pulp in a Hollander, or 10 per cent of manganous ferrocyanide is so precipitated and the paper impregnated with concentrated alkali selenite, or paper is printed with moist barium tellurite. |
