Recording media and related methods
View Patent ↗A recording medium comprises an oleophilic substrate and, thereover, a topmost oleophobic layer comprising a cured polymeric silicone matrix that consists essentially of the addition-cure reaction product of a vinyl-functional polydialkylsiloxane and a silane cross-linking agent. The vinyl-functional polydialkylsiloxane has a molecular weight ranging from 30,000 to 75,000 or 110,000 to 130,000. If the molecular weight of the vinyl-functional polydialkylsiloxane is within the range of 30,000 to 75,000, the molar ratio of silane groups to vinyl groups is within the range of about 11:1 to about 25:1; and if the molecular weight of the vinyl-functional polydialkylsiloxane is within the range of 110,000 to 130,000, the molar ratio of silane groups to vinyl groups is from about 5:1 to about 27:1. The recording medium may be used as a lithographic printing plate.
1. A recording medium comprising an oleophilic substrate and, thereover, a topmost oleophobic layer comprising a cured polymeric silicone matrix that consists essentially of the addition-cure reaction product of a vinyl-functional polydialkylsiloxane and a silane cross-linking agent, and further comprising a laser-ablatable imaging layer between the substrate and the topmost layer, wherein:
a) the vinyl-functional polydialkylsiloxane has a molecular weight ranging from 30,000 to 75,000 or 110,000 to 130,000;
b) if the molecular weight of the vinyl-functional polydialkylsiloxane is within the range of 30,000 to 75,000, a molar ratio of silane groups in the cross-linking agent to vinyl groups in the polydialkylsiloxane is within the range of about 11:1 to about 25:1; and
c) if the molecular weight of the vinyl-functional polydialkylsiloxane is within the range of 110,000 to 130,000, the molar ratio of silane groups in the cross-linking agent to vinyl groups in the polydialkylsiloxane is from about 5:1 to about 27:1
and further wherein the imaging layer (i) has a thickness no greater than 50 nm, (ii) is a thin metal/metal oxide layer and (iii) is ablatable upon exposure to a laser beam having a fluence of at least 250 mJ/cm 2 .
2. The recording medium of claim 1 , wherein the vinyl-functional polydialkylsiloxane is vinyl-functional polydimethylsiloxane.
3. The recording medium of claim 1 , wherein the vinyl-functional polydialkylsiloxane has a molecular weight ranging from 30,000 to 65,000.
4. The recording medium of claim 1 , wherein the vinyl-functional polydialkylsiloxane has a molecular weight ranging from 110,000 to 130,000 and the molar ratio of silane groups in the cross-linking agent to vinyl groups in the polydialkylsiloxane is from about 20:1 to 27:1.
5. The recording medium of claim 1 , wherein the silane cross-linking agent is a trimethylsiloxy-terminated polymethylhydrosiloxane.
6. The recording medium of claim 1 , wherein the topmost oleophobic layer has a dry coat weight of 2 g/m 2 .
7. The recording medium of claim 1 , wherein the substrate comprises a polyester film.
8. The recording medium of claim 1 , wherein the substrate comprises a metal sheet having an oleophilic coating thereover.