| 摘要 |
1,032,357. Thermographic materials. MINNESOTA MINING and MANUFACTURING CO. Nov.21, 1962 [Nov . 21, 1961], No. 44028/62. Heading G2C. A heat-sensitive copy sheet structure of the visually chemically reactive type contains as the chemical reactants an aromatic N-nitroso-amine, a non-tertiary aromatic amine, and an aromatic hydroxy azo coupler. The reactants may be disposed in intimate uniform juxtaposition in a single layer or in two adjacent layers which may be coated one above the other on a single support with part of the reactants in one layer and the remainder in the other. Alternatively the structure may comprise two sheets in face-to-face contact, a first or printing sheet having a surface coating containing a non-tertiary aromatic amine and the other or image sheet having a surface coating of an aromatic N-nitroso-amine and an aromatic hydroxy azo coupler, the image sheet preferably also containing a white pigment such as titanium dioxide Thermographic exposure may be effected by "front" or "back" printing. The supports may be of paper or polyester film and the chemical reactants may be applied in vinyl polymer coatings. The sheets should be protected from U-V during storage and if desired during exposure also with the use of a U-V filter. Storage of the sheets under high humidity conditions results in images of increased colour intensity and contrast on exposure.
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