GB1012858A - Planographic printing plates, their production and process in the production of planographic prints therefrom - Google Patents

Abstract

1,012,858. Photographic transfer processes. CHEMISCHE FABRIEK L. VAN DER GRINTEN N. V. June 28, 1963 [July 13, 1962], No. 25849/63. Heading G2C. Transfer images are made by exposing a light, sensitive material comprises a support with a hydrophilic surface, a porous hydrophobic layer and a layer containing a hydrophotic binder and a light-sensitive diacromium compound, pressing the exposed material after moistening with water or an aqueous medium in contact with a hydrophotic layer containing a non-volatile organic or inorganic alkali soluble in water and being more alkaline than sodium acetate coated on a paper support and separating the materials so that the non-exposed areas of the light sensitive and hydrophobic layers are transferred. Specified alkalies are alkali metal and alkaline earth hydroxides and carbonates, tri-sodium and -potassium orthophosphates and tetra-alkylammonium hydroxides. The light sensitive materials may be these of Specifications 761,493, 761,494 and 761,495. The hydrophitic layer of the receptor sheet may be hardened gelatin, water insolubilised polyvinyl alcohol, casein which may contain bargta, calcium carbonate, titerium dioxide or silica. In the examples, a hydrophobic layer of cellulose acetate butyrate and carbon black is coated on a cellulose acetate sheet and then with a hydrophilic layer of gelatin and a diaro-diphenylemise formalklyde condensation product, imagewise exposed, contacted with a bargta layer which has been soaked in lithium hydroxide thus transferring the non-exposed areas of the light-sensitive and hydrophobic areas to the receptor sheet, moistening with gum-arabic phosphosic acid solution to produce a printing plate.