Tinting optical substrates

1. A method for tinting an optical substrate, the method comprising:

applying a coating composition comprising:

a polymerisable monomer having a polyoxyalkylene backbone containing at least four contiguous oxyalkylene units, and

an abrasion resistant agent,

and a high crosslinking polymerisable monomer

polymerising the coating composition to form an abrasion resistant coating layer, and

introducing a tinting compound into the coating layer to thereby tint the optical substrate; and

wherein the relative amounts of the abrasion resistant agent (y) as a percentage w/w of solids and/or the high cross linking monomer (x) as a percentage w/w of total monomers is between y=−0.76x+68 and y=−0.60x+30.

2. A method for tinting an optical substrate as in claim 1 wherein the relative amounts of the abrasion resistant agent (y) as a percentage w/w of solids and/or the high cross linking monomer (x) as a percentage w/w of total monomers is between y=−0.75x+60 and y=−0.60x+30.

3. A method for tinting an optical substrate as in claim 2 wherein the relative amounts of the abrasion resistant agent (y) as a percentage w/w of solids and/or the high cross linking monomer (x) as a percentage w/w of total monomers is between y=−0.67x+50 and y=−0.60x+30.

4. A method for tinting an optical substrate as in claim 1 wherein the polymerisable monomer having a polyoxyalkylene backbone has a polyoxyethylene backbone.

5. A method for tinting an optical substrate as in claim 4 wherein the polymerisable monomer having a polyoxyalkylene backbone is a diacrylate monomer.

6. A method for tinting an optical substrate as in claim 4 wherein the polymerisable monomer having a polyoxyalkylene backbone is a dimethacrylate monomer.

7. A method for tinting an optical substrate as in claim 4 wherein the polymerisable monomer having a polyoxyalkylene backbone is selected from the group consisting of polyethylene glycol (200) diacrylate, polyethylene glycol (400) diacrylate, polyethylene glycol (600) diacrylate, polyethylene glycol (200) dimethacrylate, polyethylene glycol (400) dimethacrylate and polyethylene glycol (600) dimethacrylate.

8. A method for tinting an optical substrate as in claim 7 wherein the abrasion resistant agent is an acrylated colloidal species.

9. A method for tinting an optical substrate as in claim 8 wherein the acrylated colloidal species is selected from the group consisting of colloidal silica, titanium dioxide and zirconium dioxide.

10. A method for tinting an optical substrate as in claim 9 wherein the abrasion resistant agent is acrylated colloidal silica.

11. A method for tinting an optical substrate as in claim 10 wherein the high crosslinking polymerisable monomer is present and is selected from the group consisting of tris[2-(meth)acryloyloxy]ethyl]isocyanurate, tris(2-hydroxyethyl)isocyanurate di(meth)acrylate, N,N′,N″-tris(meth)acrylhexahydro-s-triazine, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, pentaerythritol tetra(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, triethylol propyl tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 2,2,4,4,6,6-hexahydro-2,2,4,4,6,6-hexakis(2-((2-methyl-1-oxo-2-propenyl)oxy)ethoxy)-1,3,5,2,4,6-triazatriphosphorine, tetra-, penta- and hexa-functional urethane (meth)acrylates and tricyclodecane dimethanol di(meth)acrylate. 2.

12. A method for tinting an optical substrate as in claim 11 wherein the high crosslinking polymerisable monomer is tris[(2-acryloyloxy)ethyl]isocyanurate.

13. A method for tinting an optical substrate as in claim 11 wherein the high crosslinking polymerisable monomer is tris(2-hydroxyethyl)isocyanurate diacrylate.

14. A method for tinting an optical substrate as in claim 1 wherein the optical substrate is an ophthalmic lens.

15. A method for tinting an optical substrate as in claim 1 wherein the optical substrate is formed from an aromatic polycarbonate.

16. A method for tinting an optical substrate as in claim 15 wherein the coating composition further comprises a solvent.

17. A method for tinting an optical substrate as in claim 16 wherein the solvent is selected from the group consisting of ketones and esters.

18. A method for tinting an optical substrate as in claim 17 wherein the solvent is methyl isobutyl ketone.

19. A method for tinting an optical substrate as in claim 17 wherein the solvent is ethyl acetate.

20. A method for tinting an optical substrate as in claim 17 wherein the solvent also includes isopropanol or n-butanol.

21. A method for tinting an optical substrate as in claim 1 wherein the tinting compound is a fixed dye.

22. A method for tinting an optical substrate as in claim 1 wherein the tinting compound is a photochromic dye.

23. A tinted optical substrate that is tinted according to the method of claim 1 .