Optical coating composition

Abstract

Coating compositions yielding cured coatings that exhibit excellent abrasion-resistance and hardness for use on polymeric substrates such as the front side of optical lenses, in a manner that meets or exceeds the stringent requirements for such use. The compositions include a monomeric organofunctional silane, and colloidal silica present in an amount sufficient to improve abrasion resistance as compared to a composition lacking the colloidal silica.

1 . A coating composition for forming a transparent, abrasion-resistant coating upon a substrate, the composition comprising:
 a curable silane based coating composition comprising a monomeric organofunctional silane,   colloidal silica present in an amount sufficient to improve abrasion resistance as compared to a composition lacking the colloidal silica, and   a cationic photoinitiator.   
     
     
         2 . A composition according to  claim 1  wherein the composition comprises an additional ingredient selected from the group consisting of the an organofunctional polysiloxane, one or more polymerizable monomers, and a silane coupling agent. 
     
     
         3 . A composition according to  claim 2  wherein the composition comprises both the polysiloxane and a polymerizable monomer. 
     
     
         4 . A composition according to  claim 2  wherein the composition comprises both the polysiloxane and a silane coupling agent. 
     
     
         5 . A composition according to  claim 2  wherein the composition comprise both a polymerizable monomer and a silane coupling agent. 
     
     
         6 . A composition according to  claim 2  wherein the monomers are selected from the group consisting of ethylenically unsaturated monomers, non-silane epoxies, oxetanes, alkylalkoxysilanes or tetraalkoxysilanes, vinyl ethers, and non-silane cycloaliphatic epoxies. 
     
     
         7 . A composition according to  claim 2 , wherein the silane coupling agent comprises methyltrimethoxysilane (MTMS). 
     
     
         8 . A composition according to  claim 1  wherein the composition is adapted to be cured to provide a coating that exhibit an improved combination of abrasion-resistance and hardness as compared to a coating lacking the colloidal silica. 
     
     
         9 . A composition according to  claim 2  wherein
 a) the epoxy functional alkoxy silanes of parts A and D are independently prepared from the group consisting of glycidoxymethyl-trimethoxysilane, glycidoxymethyltriethoxysilane, glycidoxymethyl-tripropoxysilane, glycidoxymethyl-tributoxysilane, β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, β-glycidoxyethyl-tripropoxysilane, β-glycidoxyethyl-tributoxysilane, β-glycidoxyethyltrimethoxysilane, α-glycidoxyethyl-triethoxysilane, α-glycidoxyethyl-tripropoxysilane, α-glycidoxyethyltributoxysilane, γ-glycidoxypropyl-trimethoxysilane, γ-glycidoxypropyl-triethoxysilane, γ-glycidoxypropyl-tripropoxysilane, γ-glycidoxypropyltributoxysilane, β-glycidoxypropyl-trimethoxysilane, β-glycidoxypropyl-triethoxysilane, β-glycidoxypropyl-tripropoxysilane, β-glycidoxypropyltributoxysilane, α-glycidoxypropyl-trimethoxysilane, α-glycidoxypropyl-triethoxysilane, α-glycidoxypropyl-tripropoxysilane, α-glycidoxypropyltributoxysilane, γ-glycidoxybutyl-trimethoxysilane, δ-glycidoxybutyl-triethoxysilane, δ-glycidoxybutyl-tripropoxysilane, δ-glycidoxybutyl-tributoxysilane, δ-glycidoxybutyl-trimethoxysilane, γ-glycidoxybutyl-triethoxysilane, γ-glycidoxybutyl-tripropoxysilane, γ-propoxybutyl-tributoxysilane, δ-glycidoxybutyl-trimethoxysilane, δ-glycidoxybutyl-triethoxysilane, δ-glycidoxybutyl-tripropoxysilane, α-glycidoxybutyl-trimethoxysilane, α-glycidoxybutyl-triethoxysilane, α-glycidoxybutyl-tripropoxysilane, α-glycidoxybutyl-tributoxysilane, (3,4-epoxycyclohexyl)-methyl-trimethoxysilane, (3,4-epoxycyclohexyl)methyl-triethoxysilane, (3,4-epoxycyclohexyl)methyl-tripropoxysilane, (3,4-epoxycyclohexyl)-methyl-tributoxysilane, (3,4-epoxycyclohexypethyl-trimethoxysilane, (3,4-epoxycyclohexypethyl-triethoxysilane, (3,4-epoxycyclohexypethyl-tripropoxysilane, (3,4-epoxycyclohexyl)-ethyl-tributoxysilane, (3,4-epoxycyclohexyl)propyl-trimethoxysilane, (3,4-epoxycyclohexyppropyl-triethoxysilane, (3,4-epoxycyclohexyl)propyl-tripropoxysilane, (3,4-epoxycyclohexyl)propyl-tributoxysilane, (3,4-epoxycyclohexyl)butyl-trimethoxysilane, (3,4-epoxycyclohexy) butyl-triethoxysilane, (3,4-epoxycyclohexyl)-butyl-tripropoxysilane, and (3,4-epoxycyclohexyl)butyl-tributoxysilane. 
 
     
     
         10 . A composition according to  claim 9  wherein the composition, when cured upon a polymeric substrate, provides improved abrasion resistance as compared to a composition lacking the colloidal silica. 
     
     
         11 . A composition according to  claim 1  wherein the composition, when cured upon a polymeric surface provides an abrasion resistance (delta haze) of less than about 10%, when determined by Taber resistance, at 1000 cycles with a 500 g load. 
     
     
         12 . A composition according to  claim 11  wherein the abrasion resistance is less than about 5%. 
     
     
         13 . A composition according to  claim 12  wherein the abrasion resistance is less than about 2%. 
     
     
         14 . A composition according to  claim 11  wherein the cured composition also provides tintability of down to 30% or less as determined by the spectrophotometric Hazegard system. 
     
     
         15 . A composition according to  claim 1  wherein the composition lacks organofunctional polysiloxane and the monomeric silane is present at a concentration of between about 40% and about 90% by weight (solids basis) of the composition. 
     
     
         16 . A composition according to  claim 15  wherein the monomeric silane is present at a concentration of between about 50% and about 80% by weight (solids basis) of the composition. 
     
     
         17 . A composition according to  claim 1  wherein the colloidal silica is present in an amount between about 1% and about 50% by weight. 
     
     
         18 . A composition according to  claim 17  wherein the colloidal is present in an amount between about 20% and about 40% by weight. 
     
     
         19 . A composition according to  claim 1  wherein
 the composition lacks organofunctional polysiloxane and the monomeric silane is present at a concentration of between about 40% and about 90% by weight (solids basis) of the composition; 
 the colloidal silica present in an amount between about 20% and about 40% by weight, and wherein 
 the composition, when cured upon a polymeric surface provides an abrasion resistance (delta haze) of less than about 5%, when determined by Taber resistance. 
 
     
     
         20 . A coating composition for forming a transparent, abrasion-resistant coating upon a substrate, the composition comprising:
 a monomeric organofunctional silane,   colloidal silica present in an amount sufficient to improve abrasion resistance as compared to a composition lacking the colloidal silica,   a cationic photoinitiator,   an organo functional polysiloxane,   one or more polymerizable monomers selected from the group consisting of ethylenically unsaturated monomers, non-silane epoxies, oxetanes, alkylalkoxysilanes or tetraalkoxysilanes, vinyl ethers, and non-silane cycloaliphatic epoxies, and   a silane coupling agent comprising methyltrimethoxysilane (MTMS).   
     
     
         21 . A polymeric substrate having cured thereon a composition according to  claim 1 . 
     
     
         22 . A substrate according to  claim 21  wherein the cured composition provides abrasion resistance (delta haze) of less than about 10%, when determined by Taber resistance, at 1000 cycles with a 500 g load. 
     
     
         23 . A substrate according to  claim 18  wherein the abrasion resistance is less than about 5%. 
     
     
         24 . A substrate according to  claim 19  wherein the abrasion resistance is less than about 2%. 
     
     
         25 . A substrate according to  claim 21  wherein the substrate itself comprises unprimed or primed polycarbonate. 
     
     
         26 . A substrate according to  claim 25  wherein the substrate is in the form of an optical lens. 
     
     
         27 . A method of providing an improved abrasion resistant coating to a polymeric substrate, the method comprising the steps of providing a coating composition according to  claim 1 , and curing the composition on the surface. 
     
     
         28 . A method according to  claim 27  wherein the substrate comprises an optical lens. 
     
     
         29 . An optical lens having cured there on a composition according to  claim 1 .