Processless lithographic printing plate
View Patent ↗A positive-working, heat-sensitive material for making a lithographic printing plate by direct-to-plate recording is disclosed. The material comprises a hydrophobized grained and anodized aluminum support and a layer comprising a compound capable of converting light into heat provided onto said support, said support being obtainable by RF plasma treatment of a grained and anodized aluminum support in the presence of a fluorine containing gas.
1. A positive-working, heat-sensitive material for making a lithographic printing plate by direct-to-plate recording, the material comprising a hydrophobized grained and anodized aluminum support and a layer comprising a compound capable of converting light into heat provided on said support, said support being obtainable by RF plasma treatment of a grained and anodized aluminum support in the presence of a fluorine containing gas.
2. A material according to claim 1 wherein the RF plasma treatment is carried out for a period of 15 to 60 minutes, utilizing a pressure of 3 to 30 Pa at a temperature of 25 to 90° C.
3. A method for making a positive-working, heat sensitive printing plate comprising the steps of:
(i) providing a heat sensitive material according to claim 2 ; and
(ii) image-wise exposing said heat-sensitive material with heat and/or light whereby at the exposed areas the contact angle for water is decreased.
4. A material according to claim 2 wherein the fluorine containing gas is a fluorinated hydrocarbon gas.
5. A material according to claim 2 wherein the fluorine containing gas is a perfluorinated hydrocarbon gas.
6. A materiai according to claim 5 wherein the fluorine containing gas is C 3 F 8 or C 4 F 8 .
7. A material according to claim 2 wherein the hydrophobized grained and anodized aluminum support comprises fluorinated hydrocarbon units.
8. A material according to claim 2 wherein the hydrophobized grained and anodized aluminum support comprises perfluorinated hydrocarbon units.
9. A material according to claim 1 wherein the fluorine containing gas is a fluorinated hydrocarbon gas.
10. A material according to claim 1 wherein the fluorine containing gas is a perfluorinated hydrocarbon gas.
11. A material according to claim 10 wherein the fluorine containing gas is C 3 F 8 or C 4 F 8 .
12. A material according to claim 1 wherein the hydrophobized grained and anodized aluminum support comprises fluorinated hydrocarbon units.
13. A material according to claim 1 wherein the hydrophobized grained and anodized aluminum support comprises perfluorinated hydrocarbon units.
14. A material according to claim 1 wherein the compound capable of converting light into heat is an infrared absorbing compound.
15. A material according to claim 14 wherein the infrared absorbing compound carries a positive charge and comprises a negative counter ion comprising at least seven fluorine atoms.
16. A method for making a positive-working, heat sensitive printing plate comprising the steps of:
(i) providing a heat sensitive material according to claim 1 ; and
(ii) image-wise exposing said heat-sensitive material with heat and/or light whereby at the exposed areas the contact angle for water is decreased.
17. A method for making a positive-working, heat-sensitive printing plate precursor comprising the steps of:
(i) hydrophobizing a grained and anodized aluminum support by RF plasma treatment of said grained and anodized aluminum support in the presence of a fluorine containing gas; and
(ii) coating a compound capable of converting light into heat onto said support,
wherein the RF plasma treatment is carried out for a period of 15 to 60 minutes, utilizing a pressure of 3 to 30 Pa at a temperature of 25 to 90° C.