GB1359522A - Light-sensitive copying compositions - Google Patents

Abstract

1359522 Photosensitive condensate KALLE AG 18 Aug 1971 [20 Aug 1970] 38762/71 Headings C3P and C3R [Also in Division G2] A photographic material preferably for screen stencils comprises a hydrophilic binder and a condensation product of a diazonium salt wherein the anion is an aliphatic or alicyclic monosulphonic acid with 1 to 6 carbon atoms, the condensation product having at least two units A-D and one unit B connected by a bivalent intermediate member derived from an active carbonyl compound wherein A is a radical of a compound containing two carboxylic and/or heterocyclic aromatic rings and can condense with a carbonyl group of an active carbonyl compound in an acid medium, D is a diazonium salt group attached to an aromatic carbon atom of A, and B is a radical of a compound free of diazonium groups and can condense with a carbonyl group of an active carbonyl compound in an acid medium. Preferred condensation products (with different anions) are those disclosed in Specifications 1,312,925 and 1,312,926. Specified binders are polyvinyl alcohols, gelatine, polyacrylic acid, hydroxy methyl cellulose and methyl cellulose. The material may be coated on one or both sides of a stencil support such as a steel, brass, bronze or nickel wire gauge, silk tissue, Japan paper or a perforated polymer. The material may contain a dye or a filler such as a polymeric dispersion, e.g. polyamides, polyesters, polyurethanes and vinyl polymers, oxides of Si, Ti or Al, clay or powdered glass. The material on the support may be imagewise exposed and developed to remove the unexposed areas thus producing a screen stencil.