Method of forming a release layer

1. A method of forming a silicone release layer on a substrate, for an intermediate transfer member of a digital offset printing system, the method including:

a) providing a curable first primer on the substrate;

b) providing a curable second primer on the substrate;

c) providing a curable silicone release formulation on the curable first and second primers; and

d) curing the first primer, the second primer and the release formulation,

wherein the first primer is curable by a condensation reaction and the second primer is curable by an addition reaction.

2. A method according to claim 1 , wherein the first primer comprises a first catalyst and the second primer comprises a second catalyst.

3. A method according to claim 2 , wherein the first catalyst comprises titanium and the second catalyst comprises platinum.

4. A method according to claim 1 , wherein the first primer comprises a first catalyst and an epoxysilane, and the first catalyst comprises an organic titanate or a titanium chelate.

5. A method according to claim 1 , wherein the second primer comprises a second catalyst, the second primer further comprises at least one of a vinyl silane, an allyl silane and an unsaturated silane, and the second catalyst comprises a Karstedt catalyst or a SIP6831.2 catalyst.

6. A method according to claim 1 , wherein the silicone release formulation comprises at least one of a vinyl silicone oil, a silicon hydride crosslinker, a Karstedt catalyst, a catalyst comprising a Pt(O) complex with vinylsiloxane ligands, an inhibitor, an acetylenic alcohol, tetramethyltetravinylcyclotetrasiloxane, tetramethyldivinyldisiloxane, a filler, amorphous silica, carbon black, a vinyl-terminated polydimethyl siloxane, a vinyl silicone, a divinyl tetramethyl disiloxane-platinum(0) complex, and an alkinol.

7. A method according to claim 1 , wherein the silicone release formulation is curable by an addition reaction using a catalyst comprising platinum.

8. A method according to claim 1 , wherein in steps a), b) and c) the substrate comprises an uncured acrylic rubber which is cured after performing steps a), b) and c).

9. A method according to claim 1 , wherein the curable first primer and the curable second primer are provided in steps a) and b) together as a mixture of the curable first and second primers.

10. The method of claim 1 , wherein curing the first primer, the second primer and the release formulation is performed simultaneously.

11. The method of claim 1 , wherein curing the first primer, the second primer, and the release formation comprises:

curing the first primer, the second primer, and the release formulation at 120° Celsius for one hour.

12. An intermediate transfer member for a digital offset printing system, comprising a substrate, a primer layer on the substrate, the primer layer comprising a first primer material and a second primer material, and a silicone release layer on the primer layer, wherein the first primer material comprises titanium and the second primer material comprises platinum.

13. An intermediate transfer member according to claim 12 , wherein the first primer material comprises an epoxysilane cured with a first catalyst comprising an organic titanate or a titanium chelate, and the second primer material comprises at least one of a vinyl silane, an allyl silane and an unsaturated silane cured with a second catalyst comprising a Karstedt catalyst or a SIP6831.2 catalyst.

14. An intermediate transfer member according to claim 12 , wherein the substrate comprises an acrylic rubber.

15. A digital offset printing system comprising an intermediate transfer member in accordance with claim 12 .