| 摘要 |
<p>The security paper contains, or is surface treated with 0.1%, pref. 0.01% of a cpd. (I) derived from a diaminostilbene sulphonic acid coupled to a phenol. The paper is used for shares certificates, cheques, official documents etc. Any attempts at alteration or forgery are revealed by colour showing up which is then difficult to erase. Use of (I) does not affect the original white colour of the paper, and it is compatible with other additives. The pulp for the paper or the coating or impregnating compsn. are pref. at pH 7.5. The paper may also contain a cpd. susceptible to oxidn. or redn. and of known decolourising properties chosen from zinc diethyldithio-carbamate; 2-mercaptobenzothiazole zinc salt; diphenylquanidine; mercaptobenzothiazole; tetramethylthiuram, disulphide; and their derivatives.</p> |
