GB1126195A - Improvements in or relating to diazotype photoprinting materials - Google Patents

Abstract

1,126,195. Heat developable diazotype materials. GENERAL ANILINE & FILM CORP. Dec. 8, 1965 [Dec.9, 1964], No. 52169/65. Heading G2C. A sensitizing composition for a heat-developable two-component diazotype printing material comprises guanidine sulphate, an azo coupling component, a light sensitive diazonium compound and a neutral or acid reagent which yields an alkaline reacting compound on heating to 100-200‹ C. The composition may be coated on paper or film e. g. regenerated cellulose or cellulose acetate. The neutral or acid reagent may be an alkali metal or ammonium salt of a strong organic acid e. g. of maleic, oxalic, malonic, benzene sulphinic, or of a carboxylic acid having 1-3 C atoms which may be α- or #- substituted by halogen, -CN or -NO 2 e.g. trichloroacetic acid. The diazonium compounds are preferably the diazotization products of N-mono- or N-disubstituted phenylene diamines. Azo coupling agents specified are 2-(m-hydroxyphenoxy)-ethanol, 2, 3- and 1, 8- dihydroxynaphthalenes, 2, 3 dihydroxynaphthalene- 6-sulphonic acid, sodium-6, 7 -dihydroxy-napthalene-2-sulphonate, phloroglucinol, resorcinol, 2-octyl and 2-methyl resorcinol, α -resocrcylamide, 3 -methyl- 1 -phenyl pyrazolone, acetoacetanilide, H-acid, and 2, 5-xylenol. Other additives include (NH 4 ) 2 SO 4 , ZnCl 2 , NiSO 4 , MgCl 2 , acid stabilizers, wetting agents, thiosinamine, 1-allyl-3-#- hydroxylethyl thiourea, 1-alkyl-thiourea, glycol, glycerine, sodium-1, 3, 6-naphthalene trisulphonate, SiO 2 and polyvinyl alcohol and acetate. The components may be applied to the base in a single step or, applied as separate layers. After imagewise exposure, the image is developed by heating to 100-200‹ C.