| 摘要 |
630,146. Electrolytic recording paper. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Nov. 29, 1946, No. 35509. Convention date, Dec. 3, 1945. Drawings to Specification. [Class 96] [Also in Groups XXXVI and XL (b)] Paper for electrolytic recording is impregnated with an aqueous alkaline solution (preferably at pH 9-11) containing benzidine-3 : 31- disulphonic acid, a water-soluble metallic nitrite to effect tetrazotization thereof, a neutral second electrolyte to facilitate the passage of an electrolysing current and, as coupling component, a mixture of a diacetoacetyl alkylene polyamine (in which the alkylene chain may be interrupted by -NH-) and a benzoyl-H-acid (in which the benzene nucleus may optionally be substituted by halogen or an acylamino, alkyl, alkoxy or aryloxy group). The solution preferably contains also an aliphatic compound containing a -CSNH 2 group, and may contain a wetting agent. Rosin sizing in the paper should be kept to a minimum to avoid darkening of the background of the records on storage. Resins produced from melamine and formaldehyde give good wet strength to the paper but may cause a shift of the colour of the record towards blue, though this may be compensated for by increasing the proportion of diacetoacetyl alkylene polyamine in the impregnating solution. Quantitative examples of impregnating solutions are given. Specification 587,540, [Group IV (b)], is referred to.
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