Abrasion-resistant optical article and process for manufacturing thereof
View Patent ↗An optical article includes a transparent substrate and an abrasion-resistant layer appended to at least one surface of the substrate. The abrasion-resistant layer results from the reaction mixture of: a first organo-silane chosen from thiocarbamate-silane matrix precursor containing at least one terminal alkoxysilane group, or hydrolysates thereof, the thiocarbamate-silane compound resulting from the reaction of a polythiol including at least two —SH thiol substituent, with an isocyanato-silane compound represented by the general formula: (R 1 ) 3 Si—R 2 —N═C═O wherein R 1 represents a group selected from linear or branched (C 1 -C 6 ) alkoxy, and R 2 represents a group selected from linear or branched (C 1 -C 6 ) alkylene, linear or branched (C 1 -C 6 ) alkenylene, arylene, and (C 5 -C 12 )cycloakylene, each of these groups being optionally substituted by one to six groups selected from halogen, alkoxy, carboxy, alkylcarbonyl, alkoxycarbonyl, and perfluoroalkyl, an inorganic oxide, a curing catalyst for said thiocarbamate-silane, and a solvent for said organo-silane.
1. An optical article comprising a transparent substrate, and a high refractive and abrasion-resistant layer coated onto at least one surface of said substrate, wherein said layer results from reacting and curing a mixture containing the following compounds:
a first organo-silane compound chosen from thiocarbamate-silane compounds containing at least one terminal alkoxysilane group, or hydrolysates thereof, said thiocarbamate-silane compound resulting from the reaction of a polythiol comprising at least two —SH thiol substituent, with an isocyanato-silane compound represented by the general formula:
(R 1 ) 3 Si—R 2 —N═C═O
wherein R 1 represents a group selected from linear or branched (C 1 -C 6 ) alkoxy, and R 2 represents a group selected from linear or branched (C 1 -C 6 ) alkylene, linear or branched (C 1 -C 6 ) alkenylene, arylene, and (C 5 -C 12 )cycloakylene, each of these groups being optionally substituted by one to six groups selected from halogen, alkoxy, carboxy, alkylcarbonyl, alkoxycarbonyl, and perfluoroalkyl, wherein the polythiol is selected from the group consisting of 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol, trimethylolpropane tris(3-mercapto propionate), pentaerythritol tetrakis(3 mercaptoacetate), trimethylolpropane tris(3-mercaptoacetate), 4-t-butyl-1,2 benzenedithiol, bis-(2-mercaptoethyl)sulfide, 4,4′-thiodibenzenethiol, benzenedithiol, glycol dimercaptoacetate, glycol dimercaptopropionate ethylenebis(3 mercaptopropionate), polyethylene glycol dimercaptoacetates, polyethylene glycol di(3 mercaptopropionates), pentaerythritol tetrakis(3-mercapto-propionate), tris-(3-mercaptopropyl)isocyanurate, 1,2,3-trimercaptopropane, 2,2-bis(mercaptomethyl)-1,3-propanedithiol, dipentaerythrithiol, 1,2,4-trimercaptomethyl benzene, 2,5-dimercaptomethyl-1,4-dithiane, bisphenofluorene bis(ethoxy-3-mercaptoproprionate), 4,8-bis(mercaptomethyl)-3,6,9 trithia-1,11-undecanedithiol, 2-mercaptomethyl-2-methyl-1,3-propanedithiol, 1,8-dimercapto-3,6-dioxaoctane, thioglycerol bismercapto-acetate, and mixtures thereof,
an inorganic oxide selected from the group consisting of iron, titanium, cerium, zirconium, antimony, zinc, tin oxides, silica, and composite oxides thereof,
a curing catalyst for said organo-silane, and
a solvent for said organo-silane.
2. Optical article according to claim 1 , wherein the coating solution comprises from 30% to 50% by weight of the inorganic oxide, based on the total weight of the solution.
3. Optical article according to claim 1 , wherein the coating solution comprises from 25% to 50% by weight of the first organo-silane, based on the total weight of the solution.
4. Optical article according claim 1 , wherein first organo-silane compound has a refractive index higher than 1.55.
5. Optical article according to claim 1 , wherein the isocyanato-silane compound comprises a R 1 group selected from methoxy, ethoxy, and propyloxy, and R 2 group selected from linear or branched (C 1 -C 6 ) alkylene, phenylene and cyclopropylene.
6. Optical article according claim 1 , wherein the polythiol is selected from the group consisting of 2-mercaptoethyl sulphide, trimethylopropane tris(3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate) and 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol.
7. Optical article according to claim 1 , wherein the isocyanato-silane is selected from the group consisting of 1-trimethoxysilane-4-isocyanato-benzene, 1-trimethoxysi lane-3-isocyanato-benzene, 1-trimethoxys lane-2-isocyanato-cyclopropane, 1-trimethoxysilane-3-isoeyanato-propane, and 3-(triethoxysilyl)propyl isocyanate.
8. Optical article according to claim 1 , wherein the inorganic oxide is selected from SiO 2 , Al 2 O 3 , SnO 2 , Sb 2 O 5 , Ta 2 O 5 , CeO 2 , La 2 O 3 , Fe 2 O 3 , ZnO, WO 3 , ZrO 2 , In 2 O 3 and TiO 2 alone or by mixture of at least two of them.
9. Optical article according to claim 1 , wherein the inorganic oxide is a TiO 2 —ZrO 2 —SiO 2 composite.
10. Optical article according to claim 1 , wherein the solvent is chosen from 1-methoxy-2-propanol, 4-hydroxy-4-methyl-2-pentanone, methanol, ethanol, iso-propanol, methyl-ethyl-cetone, and tetrahydrofurane.
11. Optical article according to claim 1 , wherein said reaction mixture further includes a second organo-silane, preferentially tetraethyl orthosilicate.
12. Optical article according to claim 1 , wherein said substrate is selected from the group consisting of sight optical systems, ocular visors, and ophthalmic lenses, said ocular visors and ophthalmic lenses optionally being untinted, tinted or photochromic.
13. Process for manufacturing an optical article according to claim 1 , comprising the steps of:
1) preparing a coating solution by mixing
a first organo-silane chosen from thiocarbamate-silane compounds containing at least one terminal alkoxysilane group, or hydrolysates thereof, said thiocarbamate-silane compound resulting from the reaction of a polythiol comprising at least two —SH thiol substituent, with an isocyanato-silane compound represented by the general formula:
(R 1 ) 3 Si—R 2 —N═C═O
wherein R 1 represents a group selected from linear or branched (C 1 -C 6 ) alkoxy, and R 2 represents a group selected from linear or branched (C 1 -C 6 ) alkylene, linear or branched (C 1 -C 6 ) alkenylene, arylene, and (C 5 -C 12 )cycloakylene, each of these groups being optionally substituted by one to six groups selected from halogen, alkoxy, carboxy, alkylcarbonyl, alkoxycarbonyl, and perfluoroalkyl,
wherein the polythiol is selected from the group consisting of 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3 mercaptoacetate), trimethylolpropane tris(3-mercaptoacetate), 4-t-butyl-1,2 benzenedithiol, bis-(2-mercaptoethyl)sulfide, 4,4′-thiodibenzenethiol, benzenedithiol, glycol dimercaptoacetate, glycol dimercaptopropionate ethylenebis(3 mercaptopropionate), polyethylene glycol dimercaptoacetates, polyethylene glycol di(3 mercaptopropionates), pentaerythritol tetrakis(3-mercapto-propionate), tris-(3-mercaptopropyl)isocyanurate, 1,2,3-trimercaptopropane, 2,2-bis(mercaptomethyl)-1,3-propanedithiol, dipentaerythrithiol, 1,2,4-trimercaptomethyl benzene, 2,5-dimercaptomethyl-1,4-dithiane, bisphenofluorene bis(ethoxy-3-mercaptoproprionate), 4,8-bis(mercaptomethyl)-3,6,9 trithia-1,11-undecanedithiol, 2-mercaptomethyl-2-methyl-1,3-propanedithiol, 1,8-dimercapto-3,6-dioxaoctane, thioglycerol bismercapto-acetate, and mixtures thereof,
an inorganic oxide selected from the group consisting of iron, titanium, cerium, zirconium, antimony, zinc, tin oxides, silica, and composite oxides thereof,
a curing catalyst for said organo-silane, and
a solvent for said organo-silane,
2) coating a substrate with said solution, and
3) curing the coating, thereby obtaining a high refractive and abrasion-resistant layer coated onto said substrate.
14. Process according to claim 13 , wherein the coating solution further contains a second organo-silane representing from 5% to 20% by weight of the total weight of the solution.
15. Process according to claim 13 , wherein after curing step 3), the coating comprises:
25 to 50 wt % of matrix derived from a thiocarbamate-silane as a first organo-silane compound,
30 to 50 wt % of an inorganic oxide,
0 to 20 wt % of matrix derived from a second organo-silane compound, and
0.1 to 0.5 wt % of a catalyst.
16. Process according to claim 13 , wherein after curing step 3), the coating comprises:
50 wt % of matrix derived from a thiocarbamate-silane precursor as a first organo-silane compound,
30 wt % of a inorganic oxide,
20 wt % of matrix derived from a second organo-silane compound, and
0.1 to 0.5 wt % of a catalyst.
17. An ophthalmic lens comprising an optical article according to claim 1 wherein the ophthalmic lens is an afocal, unifocal, bifocal, trifocal, or progressive lens.