| 摘要 |
<p>A support material comprises a film of polyethylene terephthalate or cellulose acetate butyrate with a coating thereon produced by the application thereto e.g. by dipping, brushing, spraying, roller-coating or by a contact coating device, of a solution, in a solvent containing trichloracetic acid, trifluoracetic acid or benzophenone, of a copolymer of esters of acrylic and methacrylic acids and/or a thermosetting acrylic polymer or cellulose acetate, polyvinyl butyral, polyvinyl formal, polyvinyl chloride, alkyd resin, or melamine-formaldehyde resin, and removal of the solvent. The solution may contain calculated on the total weight of the solution, 0.4 to 20% by weight of trichloracetic or trifluoroacetic acid, 0.02 to 10% by weight of Acryloid B44 (a polymer of esters of acrylic and methacrylic acids) and 0.02 to 10% by weight of Acryloid AT-50 (a thermosetting acrylic polymer). A further coating that is compatible with and adherent to the initial coating may be applied e.g. by dipping. The further coating may be of an acrylic polymer, cellulose ester, or a gelatin composition. Specified further coatings may be photosensitive and comprise acrylic resins as binders, silica pigment for taking pencil marks, photosensitive diazonium compound, colour forming coupler and ancillary chemicals such as thiourea, boric acid, citric acid, and tartaric acid; a lacquer suitable for taking pencil markings comprising acrylic resin, melamine formaldehyde resin and finely divided silica pigment.</p> |
