| 摘要 |
PURPOSE:To improve dye transfer properties, enhance performance of a heat- resistant slipping layer and contrive a thinner heat-resistant slipping layer, namely, a higher sensitivity of a thermal transfer sheet, by providing the heat- resistant slipping layer by using a reaction product obtained by a reaction of a thermoplastic resin comprising hydroxyl groups with an isocyanate in a specified ratio, a phosphoric acid ester surface active agent and a filler. CONSTITUTION:A thermoplastic resin comprising hydroxyl groups and an isocyanate are used in such a ratio that the equivalent ratio of isocyanate/ hydroxyl is 0.8-2.5. If the ratio is less than 0.8, a dye in a thermal transfer layer 2 migrates into a heat resistant slipping layer 4 upon close contact of the layers 2 and 4, resulting in poor preservability of a thermal transfer sheet. On the other hand, when the ratio exceeds 2.5, a sticking phenomenon occurs, leading to poor feedability of the thermal transfer sheet during recording. As the thermoplastic resin, polyvinyl butyral is particularly preferred because it reacts with the isocyanate to form a resin having favorable heat resistance. The isocyanate may be a polyisocyanate such as diisocyanate and triisocyanate, which may be used either singly or in combination. |
