| 摘要 |
PURPOSE:To obtain a developed color image having a continuous gradation, a high density and high preservability, by incorporating a heteropolyacid or a salt thereof as a color developer in a color developer layer, in a thermal transfer recording sheet used in combination with a thermal transfer sheet. CONSTITUTION:A heteropolyacid such as phosphotungstic acid and phosphomolybdic acid or a salt thereof, preferably, a compound obtained by treating a heteropolyacid with an ammonium compound or an amine derivative, is applied to a base 2 together with a binder resin to provide a color developer layer 3. The amount of the heteropolyacid is 1-95wt% of the total weight of the color developer layer. The color developer layer may comprise other color developer and may comprise a UV light absorber or an excited oxygen catching agent in an amount of 10wt% to the binder. The binder resin used in the color developer layer 3 is preferably a resin having a low glass transition temperature or a resin containing sulfonic acid residues. Further, a protective layer 4 may be provided on the color developer layer 3. |
