Claims
- 1. A thermal transfer sheet comprising a substrate film, a recording material layer formed on one surface side of the substrate film, and a back coating layer formed on the other surface side of the substrate film to be in contact with a thermal head, wherein the back coating layer comprises a binder which excludes silicone resins and predominantly comprises a styrene-acrylonitrile copolymer, the styrene-acrylonitrile copolymer having an acrylonitrile copolymerization ratio of 20 to 40 mol %, a molecular weight of 10.times.10.sup.4 to 20.times.10.sup.4 and a softening point of about 400.degree. to about 450.degree. C., and the back coating layer has a thickness of 0.01 to 0.5 .mu.m.
- 2. A thermal transfer sheet comprising a substrate film, a recording material layer formed on one surface side of the substrate film, and a back coating layer formed on the other surface side of the substrate film to be in contact with a thermal head, wherein the back coating layer comprises a binder predominantly comprising a styrene-acrylonitrile copolymer having an acrylonitrile copolymerization ratio of 20 to 40 mol %, a molecular weight of 10.times.10.sup.4 to 20.times.10.sup.4 and a softening point of 400.degree. to 450.degree. C., at least two species of heat-resistant particles having different particle sizes the ratio between the weight of the larger species of particle and that of the smaller species of particle being from 20 to 80 to 80 to 20, and an alkylphosphate multi-valent metal salt compound represented by the following formula: ##STR2## wherein R denotes an alkyl group having 12 to 20 carbon atoms; M denotes a zinc cation or an aluminum cation; and n denotes the valence of M the smaller species of particle having a particle size which is 0.5 to 0.1 times the particle size of the larger heat-resistant particles, the larger species of particle having a particle size of 1/2x to x, wherein x denotes the thickness of the back coating layer, the total amount of the heat-resistant particles being 10 to 200 wt. parts with respect to 100 wt. parts of the binder, the smaller species of particle filling gaps between the larger species of particle, the alkylphosphate multi-valent metal salt being contained in the back coating layer in an amount of 10 to 150 wt. % with respect to the binder, the alkylphosphate multi-valent metal salt having a melting point of 150.degree. to 250.degree. C. and the back coating layer having a thickness of 0.1 to 0.5 .mu.m.
Priority Claims (2)
Number |
Date |
Country |
Kind |
1-176537 |
Jul 1989 |
JPX |
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1-176538 |
Jul 1989 |
JPX |
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FIELD OF THE INVENTION AND RELATED ART
This is a continuation-in-part of Ser. No. 105,457 now abandoned which was filed Aug. 10, 1993 and which was a divisional of Ser. No. 548,094 filed Jul. 5, 1990, now U.S. Pat. No. 5,260,127. Each of these applications are hereby incorporated by reference.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4925735 |
Koshizuka et al. |
May 1990 |
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5260127 |
Umise et al. |
Nov 1993 |
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Divisions (1)
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Number |
Date |
Country |
Parent |
548094 |
Jul 1990 |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
105457 |
Aug 1993 |
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