Patent ID: 8609584

Claim:
A thermal transfer sheet comprising: a thermal transfer dye layer formed on one surface of a base sheet and containing a dye; and a heat resistant smooth layer formed on the other surface of the base sheet and containing: a binder; a lubricant; and a filler; wherein the binder contained in the heat resistant smooth layer is obtained by mixing a polyvinyl acetoacetal resin with an acryl silicone resin, which has a mass average molecular weight of 100,000 or more and is in the form of a powdery solid at an ordinary temperature, at a ratio of 10 parts by mass or less of the acryl silicone resin relative to 100 parts by mass of the polyvinyl acetoacetal resin; and wherein the heat resistant smooth layer further contains: 10 parts by mass or more and 30 parts by mass or less of an isocyanate relative to 100 parts by mass of the polyvinyl acetoacetal resin; and a phosphoric acid ester having a melting point of 50° C. or more as the lubricant.