Granted Patent B2

US 8,771,926 · App. 13/169,296 · Granted Jul 8, 2014

Abstract

Claims (27)

1. A method of preparing a photosensitive printing blank, the method comprising the steps of:

a) coating a slip film onto a coversheet and drying the slip film; and

b) depositing at least one layer of photosensitive material on top of the dried slip film coated coversheet and laminating a substrate layer to an exposed face of the at least one layer of photosensitive material;

wherein the slip film comprises:

i) a polymer selected from the group consisting of polystyrene and polyvinylpyrrolidone; and

ii) 0.1 to 5.0 percent by weight of an additive, where the additive is selected from the group consisting of ethylene glycol, propylene glycol, mineral oils, styrene-butadiene oils, butadiene oils, and copolymers of acetonitriles;

wherein prior to drying, the slip film also comprises a solvent selected from the group consisting of toluene, acetone, primary alcohols, methylethyl ketone, 2-propanol, and combinations of one or more of the foregoing.

2. The method according to claim 1 , wherein the concentration of the polymer in the slip film, prior to drying, is between about 6 to about 30 percent by weight.

3. The method according to claim 2 , wherein the concentration of the polymer in the slip film, prior to drying, is between about 6 to about 11 percent by weight.

4. The method according to claim 1 , wherein the concentration of the solvent in the slip film prior to drying is between about 65 to about 95 percent by weight.

5. The method according to claim 4 , wherein the concentration of the solvent in the slip film prior to drying is between about 85 to about 95 percent by weight.

6. The method according to claim 1 , wherein the concentration of the additive in the slip film, prior to drying, is between about 0.5 to about 3.5 percent by weight.

7. The method according to claim 1 , wherein the thickness of the slip film is between about 1.0 and about 15.0 grams per square meter.

8. The method according to claim 7 , wherein the thickness of the slip film is between about 2.0 and about 5.0 grams per square meter.

9. The method according to claim 8 , wherein the thickness of the slip film is about 2.5 grams per square meter.

10. The method according to claim 1 , wherein the slip film does not include a polyamide.

11. The method according to claim 1 , wherein the slip film comprises polystyrene as the polymer.

12. The method according to claim 11 , wherein the additive is present in the slip film and comprises a co-polymer of acetonitrile.

13. The method according to claim 1 , wherein the slip film comprises polyvinylpyrrolidone as the polymer.

14. The method according to claim 13 , wherein the additive is present in the slip film and comprises a co-polymer of acetonitrile.

15. The method according to claim 1 , further comprising the steps of:

a) removing the coversheet from the slip film and the at least one layer of photosensitive material;

b) placing a negative on top of the slip film;

c) exposing the at least one layer of photosensitive material to actinic radiation through the negative to selectively crosslink and cure the at least one layer of photosensitive material and produce a relief image printing element;

wherein the presence of the slip film at least substantially eliminates the formation of hot spots in the relief image printing element.

16. The method according to claim 1 , wherein the solvent comprises toluene.

17. The method according to claim 1 , wherein the solvent comprises acetone.

Assignments (9)