Claims
- 1. A thermographic recording film comprising a support carrying:
- (a) an image-forming system; and
- (b) a protective layer comprising at least one colloidal silica and water-insoluble binder material, said protective layer positioned above said image-forming system or positioned below the surface of said support opposite that which carries said image-forming system, said thermographic recording film additionally including a compound containing at least two epoxide moieties in said protective layer and/or in a layer adjacent to the surface of said protective layer remote from said support, the ratio of colloidal silica to the total amount of said compound containing at least two epoxide moieties and said binder material being at least 2:1 by weight.
- 2. A thermographic recording film according to claim 1 wherein said water-insoluble binder is an aliphatic polyurethane.
- 3. A thermographic recording film according to claim 1 wherein said compound containing at least two epoxide moieties is a diepoxy crosslinking compound.
- 4. A thermographic recording film according to claim 3 wherein said diepoxy crosslinking compound is 1,4-butanediol diglycidyl ether.
- 5. A thermographic recording film according to claim 3 wherein said diepoxy crosslinking compound is bis(3,4-epoxycyclohexyl)adipate.
- 6. A thermographic recording film according to claim 1 wherein said compound containing at least two epoxide moieties is present in said protective layer.
- 7. A thermographic recording film according to claim 6 which additionally includes a compound containing at least two epoxide moieties in a layer adjacent to the surface of said protective layer remote from said support.
- 8. A thermographic recording film according to claim 1 wherein said compound containing at least two epoxide moieties is present in a layer adjacent to the surface of said protective layer remote from said support.
- 9. A thermographic recording film according to claim 1 wherein said protective layer comprises at least two colloidal silicas having different average particle diameters in the proportion by weight of 1 part of silica particles having an average diameter of 50 nm or smaller, and 0.3 to 2.0 parts of silica particles having an average particle diameter no more than 40% of the larger sized silica particles.
- 10. A thermographic recording film according to claim 9 wherein one of said colloidal silicas is a fumed colloidal silica having an average particle diameter in the range of 14 nm to 30 nm.
- 11. A thermographic recording film according to claim 1 wherein said protective layer comprises two colloidal silicas, wherein one of said colloidal silicas is fumed colloidal silica having an average diameter of 14 nm.
- 12. A thermographic recording film according to claim 11 wherein the second colloidal silica is a colloidal silica having an average particle diameter of 5 nm.
- 13. A thermographic recording film according to claim 1 wherein said image-forming system is a dye image-forming system.
- 14. A thermographic recording system as defined in claim 13 wherein said dye image-forming system comprises a di- or triarylmethane thiolactone dye precursor, an organic silver salt, a heat-fusible organic acidic material and a polymeric binder.
- 15. A thermographic recording film according to claim 14 wherein said organic silver salt, said polymeric binder and said thiolactone dye precursor are carried in one layer on said support and said heat-fusible organic acidic material is in an adjacent layer.
- 16. A thermographic recording film according to claim 14 wherein said dye image-forming system further comprises a second heat-fusible organic acidic material.
- 17. A thermographic recording film according to claim 1 wherein said protective layer further comprises a lubricating agent.
- 18. A thermographic recording film according to claim 17 wherein said lubricating agent is polytetrafluoroethylene.
- 19. A thermographic recording film according to claim 1 wherein the ratio of said silica to the total of said binder and said compound containing at least two epoxide moieties is 2.5:1 to 5:1.
- 20. A thermographic recording film according to claim 1 wherein said protective layer further comprises a surfactant.
- 21. A thermographic recording film according to claim 20 wherein said surfactant is a nonionic fluorosurfactant.
- 22. A thermographic recording film according to claim 1 wherein said polymeric binder is polyvinylbutyral.
- 23. A thermographic recording film according to claim 1 wherein said protective layer further comprises a second binder.
- 24. A thermographic recording film according to claim 1 wherein said support is a transparent support.
- 25. A thermographic recording film according to claim 1 wherein said protective layer is positioned above said image-forming system.
- 26. A thermographic recording film according to claim 1 wherein said protective layer is positioned on the surface of said support opposite that which carries said image-forming system.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of prior copending application Ser. No. 08/009,829, filed Jan. 27, 1993, now U.S. Pat. 5,278,127.
US Referenced Citations (7)
Foreign Referenced Citations (4)
Number |
Date |
Country |
250558 |
Jan 1988 |
EPX |
0521423 |
Jan 1993 |
EPX |
3435513 |
Apr 1985 |
DEX |
2210702 |
Jun 1989 |
GBX |
Non-Patent Literature Citations (3)
Entry |
Patent Abstracts of Japan, vol. 12, No. 142 (M-692) [2989], Apr. 30, 1988. |
Patent Abstracts of Japan, vol. 12, No. 149 (M-694) [2996], May 10, 1988. |
Iler, R. K., The Chemistry of Silica, John Wiley & Sons, N.Y., 1979, pp. 369-372. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
9829 |
Jan 1993 |
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