| 摘要 |
A coating process for aluminium or aluminised substrates comprises (a) applying a monobasic phosphate layer; (b) firing the layer at at least 230 deg.C to form a ceramic coating; and (c) coating the ceramic coating with an organic photosensitive lithographic layer. - Also claimed is prepn. of a photosensitive substrate by the above process but in which step (a) comprises applying a slurry of monobasic phosphate(s) and inorganic non-metallic particles (pref. alumina and opt. other reactive metal oxides). - The processes are used to prepare lithographic printing plates. The ceramic layer (comprising glass or polymorphic forms of aluminium phosphate) provides excellent adhesion for diazonium resins and photopolymeric compsns. The inorganic particles provide a surface texture and improved chemical stability. Thus, the coated substrate is durable, is resistant to the chemical action of printing plate developers and press solvents, does not require primers or other adhesion promoting agents, and does not require etching, anodising or other texturising. EPAB- EP--87469 B A process for preparing a photosensitive substrate comprising the steps of A. Providing a ceramic layer on an aluminium substrate or aluminised surface of a substrate which comprises applying a slurry of at least one monobasic phosphate and inorganic non-metallic particles on at least one surface of the aluminium or aluminised substrate and firing the slurry at a temperature of at least 230 deg.C to form a ceramic coating on said aluminium or aluminised surface; B. Coating on said ceramic layer an organic photosensitive lithographic layer. (14pp) USAB- US4420549 A Article comprises Al or aluminised substrate having on at least one surface a ceramic coating of a polymeric form of opt. mixts. of aluminium phosphate(s). The coating is free of particulate material. A photosensitive layer is coated on the ceramic layer. - Pref. the coating is between 0.5 and 5 micrometers thick and the aluminium is in the form of film or sheet. Pref. the photosensitive layer comprises organic polymerisable compsn. esp. an oligomeric diazonium resin coated on ceramic layer. - The coating layer gives excellent surface for adhesion of organic materials that are used in printing esp. planographic printing. (5pp)s
|
