| 摘要 |
1,271,713. Diazotype materials. MINNESOTA MINING & MFG CO. April 21, 1969 [April 22, 1968], No. 20300/69. Heading G2C. A heat-developable diazotype material having at least two layers, one layer containing a heatsoftenable polymeric binder, a diazonium salt and an acid stabilizer (this being optional if the diazonium salt is an acid salt) and the other layer containing a heat-softenable polymeric binder and a benzimidazole as an acid neutralizer, at least one of the layers containing a coupler and at least 50% of the basic equivalents for neutralization being provided by the benzimidazole. Preferably the second layer is coated using a non-solvent for the first layer to avoid mixing of components. Preferred benzimidazoles are those specified in Specification 1, 032, 508. In the examples a support is coated with a layer of vinyl chloride vinyl acetate copolymer, a polyamide, or polyvinylatcohol, a benzimidazole and optionally a coupler and overcoated with a layer containing a diazonium salt, a coupler, a cellulose ester, polyvinylacetate or polystyrene and usually an acid. The material is image-wise exposed and heat-developed to give an azo dye image. There may be an intermediate layer of styrene polymer or copolymer which may contain a coupler between the benzimidazole and diazonium layers. Phloretin is specified as a coupler. |
