Thermographic recording material with improved developability
View Patent ↗A black and white thermographic recording material comprising a thermosensitive element and a support, the thermosensitive element containing at least one substantially light-insensitive organic silver salt, a binder and optionally photosensitive silver halide, characterized in that the thermosensitive element further contains deliberately added metal nano-particles in a molar ratio with respect to the total molar concentration of the at least one substantially light-insensitive organic silver salt in the range of 0.05:1 to 10 −6 :1; and the use for the purpose of increasing the ratio of D max to the quantity of said substantially light-insensitive organic silver salts per unit area of the above-mentioned thermographic recording material.
1. A dispersion comprising at least one substantially light-insensitive organic silver salt, a suspending medium and deliberately added metal nano-particles in a molar ratio with respect to the total molar concentration of said at least one substantially light-insensitive organic silver salt in the range of 0.05:1 to 10 −6 :1, wherein said at least one substantially light-insensitive organic silver salt is substantially insoluble in said suspending medium.
2. The dispersion according to claim 1 , wherein said metal is selected from the group consisting of silver, gold and palladium and alloys thereof.
3. The dispersion according to claim 1 , wherein said dispersion further comprises photosensitive silver halide.
4. A process for producing a dispersion containing at least one substantially light-insensitive organic silver salt, a suspending medium and deliberately added metal nano-particles in a molar ratio with respect to the total molar concentration of said at least one substantially light-insensitive organic silver salt in the range of 0.05:1 to 10 −6 :1, wherein said at least one substantially light-insensitive organic silver salt is substantially insoluble in said suspending medium, comprising the steps of: (i) preparing a dispersion of said at least one light-insensitive organic silver salt, (ii) preparing a dispersion of metal nano-particles; and (iii) mixing the dispersion of metal nano-particles of step (ii) with the dispersion of said at least one light-insensitive organic silver salt of step (i).
5. The process according to claim 4 , wherein the deliberately added metal nano-particles are silver.
6. The process according to claim 5 , wherein the deliberately added silver nano-particles are ex-situ silver nano-particles.
7. The process according to claim 6 , wherein said at least one substantially light-insensitive organic silver salt is a silver salt of a fatty acid.
8. The process according to claim 6 , wherein said dispersion further comprises photosensitive silver halide.
9. The process according to claim 8 , wherein said dispersion further comprises a toning agent.
10. A dispersion comprising at least one substantially light-insensitive organic silver salt, a suspending medium and deliberately added silver nano-particles in a molar ratio with respect to the total in molar concentration of said at least one substantially light-insensitive organic silver salt in the range of 0.05:1 to 10 −6 :1, wherein said at least one substantially light-insensitive organic silver salt is substantially insoluble in said suspending medium.
11. The dispersion according to claim 10 , wherein the deliberately added silver nano-particles are ex-situ silver nano-particles.
12. The dispersion according to claim 11 , wherein said at least one substantially light-insensitive organic silver salt is a silver salt of a fatty acid.
13. The dispersion according to claim 12 , wherein said dispersion further comprises photosensitive silver halide.
14. The dispersion according to claim 13 , wherein said dispersion further comprises a toning agent.
15. The dispersion according to claim 10 , wherein said at least one substantially light-insensitive organic silver salt is a silver salt of a fatty acid.
16. The dispersion according to claim 10 , wherein said dispersion further comprises a toning agent.
17. The dispersion according to claim 10 , wherein said dispersion further comprises photosensitive silver halide.