Optical article containing self-healing and abrasion-resistant coatings
View Patent ↗The present invention is drawn to an optical article comprising: (a) a transparent optical polymer substrate, (b) a transparent intermediate abrasion-resistant coating obtained from at least one epoxysilane by a sol-gel process, and (c) a transparent outer coating comprising a polythiolene matrix obtained by curing a liquid monomer mixture comprising at least one polyfunctional thiol and at least one polyfunctional allyl monomer, said cured polythiol-ene matrix having a glass transition temperature comprised in the range from 40° C. to 70° C. and a thickness from 3.5 μm to less than 10 μm. It is also drawn to a method for preparing such an optical article and to a method for repairing scratches in such an optical article by heating.
1. An optical article, comprising:
a transparent optical polymer substrate;
a transparent intermediate abrasion-resistant coating obtained from at least one epoxysilane; and
a transparent outer coating comprising a polythiol-ene matrix, said polythiol-ene matrix having a glass transition temperature in the range from 40° C. to 70° C.
2. The optical article of claim 1 , wherein the at least one epoxysilane is obtained by a sol-gel process.
3. The optical article of claim 1 , wherein the polythiol-ene matrix comprises a thickness from 3.5 μm to less than 10 μm.
4. The optical article of claim 1 , wherein the polythiol-ene matrix comprises a cured liquid monomer mixture of at least one polyfunctional thiol and at least one polyfunctional allyl monomer.
5. The optical article according to claim 4 , wherein the polyfunctional thiol is a tetrathiol of formula
6. The optical article according to claim 4 , wherein the polyfunctional allyl monomer is triallyl isocyanurate.
7. The optical article according to claim 1 , wherein the intermediate abrasion resistant coating is obtained by curing a composition prepared by a sol-gel process from a mixture which comprises: (a) at least one epoxysilane, (b) optionally, at least one alkoxysilane which does not contain any reactive functional group but optionally contains at least one nonhydrolysable organic group, (c) preferably, a colloidal inorganic binder, and (d) optionally, a catalyst.
8. The optical article according to claim 1 , wherein the outer coating further comprises conductive mineral colloids dispersed therein, preferably selected from the group consisting of Sb 2 O 5 , SnO 2 , ATO (SnO 2 /Sb 2 O 5 ), PTO (SnO 2 /P 2 O 5 ).
9. The optical article according to claim 1 , wherein the transparent outer coating comprises from 0.5 to 7% by weight of conductive mineral colloids dispersed therein.
10. The optical article according to claim 1 , wherein the transparent outer coating comprises from 1 to 6% by weight of conductive mineral colloids dispersed therein.
11. The optical article according to claim 1 , wherein the transparent outer coating further comprises a surfactant not exceeding 0.2% by weight of the transparent outer coating.
12. The optical article according to claim 1 , wherein said article comprises a lens.
13. A method for suppressing scratches on an optical article according to claim 1 , said method comprising heating said article to a temperature at least equal to the glass transition temperature of the polythiol-ene matrix.
14. A method for preparing an optical article, the method comprising the steps of:
providing a transparent optical substrate;
preparing a composition from a mixture comprising at least one epoxysilane;
coating said composition onto said transparent optical substrate and curing said composition to form an abrasion-resistant coating;
preparing a liquid monomer mixture comprising at least one polyfunctional thiol and at least one polyfunctional allyl monomer, and
coating the resulting liquid monomer mixture onto the abrasion-resistant coating and curing the resulting liquid monomer mixture to form a self-healing layer.
15. The method of claim 14 , wherein the step of preparing said composition includes preparing said composition by a sol-gel process.
16. The method of claim 15 , further comprising the step of dispersing a conductive mineral colloid in said liquid monomer mixture.
17. The method of claim 16 , wherein the self-healing layer comprises from 0.5 to 7% by weight of the conductive mineral colloid dispersed therein.
18. The method of claim 14 , wherein the self-healing layer comprises a thickness from 3.5 μm to less than 10 μm.
19. The method of claim 14 , wherein the abrasion-resistant coating is obtained by curing the composition prepared by a sol-gel process from a mixture which comprises: (a) the at least one epoxysilane, (b) optionally, at least one alkoxysilane which does not contain any reactive functional group but optionally contains at least one non-hydrolyzable organic group, (c) a colloidal inorganic binder, and (d) optionally, a catalyst.
20. The method of claim 14 , wherein said article comprises a lens.