Light sensitive coatings for screen printing comprising a light sensitive material with a condensate of a omega, omega'-diamine and a omega, omega'-dicarboxylic acid

摘要

942,824. Light-sensitized materials for stencil production. KALLE A. G. Sept. 27,1960 [Oct. 2, 1959], No. 33169/60. Headings G2C and G2M. A porous support is provided with a coating including an N-alkoxy-methylated partially depolymerized polycondensate of an #,#SP1/SP-diamine with an #,#SP1/SP-dicarboxylic acid which is soluble in aqueous alcohol or in aliphatic alcohols, and is sensitized as with a bichromate, diazonium compound or an azido-styryl compound. Procedure therewith is exposure as under a diapositive and treatment with aqueous alcohol to leave a stencil. In Example 1 4, 4SP1/SP-diazidostilbene-2, 2SP1/SP-disulphonic acid sodium salt in aqueous ethylene glycol monomethyl ether is added to a commercial polyadipic acid hexamethylene diamine type polyamide, which had been partially depolymerized by strong acid and subsequently methylated with paraformaldehyde, in aqueous alcohol and the mixture is coated by immersion and draining or spraying on to a support as of Japanese-fibre paper, polyamide, polyester, silk, glass or metal fabric, exposed and developed with aqueous methyl, ethyl or propyl alcohol to make a stencil suitable for very prolonged use. Example 2 uses, similarly, ammonium bichromate as sensitizer; Example 3 a polysebacic acid type polyamide in the manner of Example 1; Example 4 the tetrazoborofluoride from 4, 4SP1/SP- diaminostilbene as sensitizer with the polyamide material of Example 1 and describes prolonged exposure to produce cross-linking and provide a stencil resistant to hydrofluoric acid for the etching of glass, and Example 5 eleven further azido compounds for replacement of the sensitizers of Examples 1-3.