Release films

1. A release film having a layer of material comprising a metal or metal-containing compound deposited thereon, said release film comprising a substrate coated on at least one surface thereof with a release layer, said release layer comprising a layered silicate and having said material layer deposited thereon by a deposition process so as to form a thin film of 0.005 to 50 microns, said deposited material layer being releasable to obtain said material, wherein the release layer comprises a layered silicate plus binder and wherein the binder comprises melamine fomaldehyde and/or a derivative thereof.

2. A release film according to claim 1 , wherein the substrate comprises a polyimide substrate or a metal substrate.

3. A release film according to claim 1 , wherein the layered silicate comprises one or more silicates selected from vermiculite, laponite, hectorite, montmorillonite or other smectite.

4. A release film according to claim 3 , wherein the layered silicate comprises vermiculite.

5. A release film according to claim 1 , wherein the deposited material of a metal or metal-containing compound has been deposited by vacuum or vapour deposition.

6. A release film according to claim 1 , wherein the deposited material comprises a metal or metal compound selected from aluminium, chromium, magnesium, copper, vanadium, nickel, zinc, tin, silver, gold, titanium, silicon, bismuth or oxides, nitrides, fluorides and carbides thereof.

7. A release film according to claim 6 , wherein the metal compound is VO 2 .

8. A release film according to claim 1 , wherein the layer of deposited material comprises a series of layers.

9. A release film according to claim 1 , wherein the thickness of the release layer is 0.02 - 2 microns.

10. A release film having a layer of material comprising a metal or metal-containing compound deposited thereon, said release film comprising a substrate coated on at least one surface thereof with a release layer, said release layer comprising a layered silicate and having said material layer deposited thereon by a deposition process so as to form a thin film of 0.005 to 50 microns, said deposited material layer being releasable to obtain said material wherein a layer of adhesive is deposited on the layer of deposited material, and a removable liner is disposed in contact with the layer of adhesive.

11. A method of making a release film having a layer of material comprising a metal or metal-containing compound deposited thereon, said release film comprising a substrate coated on at least one surface thereof with a release layer, said release layer comprising a layered silicate and having said material layer deposited thereon by a deposition process so as to form a thin film of 0.005 to 50 microns, said deposited material layer being releasable to obtain said material, said method comprising the steps of;

coating a substrate on at least one surface thereof with an aqueous solution of layered silicate,

heating the coated substrate at a temperature sufficient for drying the layered silicate to the film,

depositing a layer of material comprising a metal or metal-containing compound onto the coated film by a deposition process so as to form a thin film of 0.005 to 50 microns, said deposited material layer being releasable to obtain said material, and

releasing the layer of material from the coated film, wherein the layer of material is released in aqueous conditions.

12. A method of making a release film according to claim 11 , wherein the layer of material is deposited by a vapour or vacuum deposition process.

13. A method of making a release film according to claim 11 , wherein heat is applied before and/or during and/or after the deposition of the layer of material.

14. A method according to claim 13 , wherein the heating occurs at a temperature of 150° C. or above.