GB1378861A - Light-sensitive copying compositions - Google Patents

Abstract

1378861 Photo-sensitive materials KALLE AG 22 Nov 1971 [23 Nov 1970] 54048/71 Heading G2C A photo-sensitive material comprising (1) a condensable diazonium salt of formula:- wherein R 1 to R 4 are hydrogen, halogen, alkyl with 1 or 2 C atoms or alkoxy with 1 to 4 C atoms and Y is either a single bond or-o-, -s-, -NH-, or- CONH- and X is an anion or a triazene derived therefrom, (2) a water-soluble polymeric binder free from cross-linking groups and (3) a substance which is capable of cross-linking the binder in the presence of the diazonium salt and being either (a) a compound containing a methylol group or an esterified or etherified methylol group containing 1 to 4 C atoms in the acyl or alkyl group or (b) a compound containing an acetal, semi-acetal or cyclic acetal group obtained by reaction of a methylol group with an aldehyde with 1 to 4 C atoms. The material may be coated on a screen support, imagewise exposed, developed, optionally heated to harden the resist, to produce a screen stencil. The light-sensitive layer may contain a dye and a plasticizer such as dibutylphthalate. Alternatively a Cu foil/epoxy resin laminate may be used as a support and printed circuits be produced. The water-soluble polymer may be polyvinyl alcohol which may be partially acetylated, gelatine, casein, polyacrylic acid, partially hydrolyzed polyvinyl acetate and methyl or hydroxyethyl cellulose. Specified cross-linking agents are those where the above specified groups are directly attached to (a) the nitrogen atom of a primary or secondary amide, urea or melamine or (b) a phenol or phenol ether or a heterocyclic compound. N, N-dimethylol urea is the preferred compound but compounds such as glycollic acid and N-methylol- 4-azido-benzamide or-cinnamic amide and polymers such as polyvinyl hydroxymethyl ether and N-methylol polyacrylamide may be used.