Organic-inorganic hybrid polymer and method of making same

Abstract

An optically clear protective thin film having covalent chemical bonds on a molecular level between organic polymer and in situ generated silica molecules is formed from a hydrolyzed coating solution of tetraalkyl orthosilicate, epoxyalkylalkoxy silanes, (math)acryloxyalkylalkoxy silanes and solvent.

What is claimed:  
     
         1 . A thermally curable coating solution for applying optically clear protective thin films to substrate surfaces, said solution including oligomers from hydrolysis of tetraalkyl orthosilicate, epoxyalkylalkoxy silanes, (math)acryloxyalkylalkoxy silanes, and solvent, and having a pH of 4-6.  
     
     
         2 . The solution of  claim 1  wherein said tetraalkyl orthosilicate, said epoxyalkylalkoxy silanes and said (math)acryloxyalkylalkoxy silanes together comprise 20-50 weight percent of said solution.  
     
     
         3 . The solution of  claim 1  wherein said solution contains a surfactant and a catalyst, said solvent being 20-80 weight percent of said solution, and 20-50 weight percent of said solvent being water.  
     
     
         4 . The solution of  claim 1  wherein said tetraalkyl orthosilicate is present in an amount greater than said epoxyalkylalkoxy silanes, and said epoxyalkylalkoxy silanes is present in an amount greater than said (math)acryloxyalkylalkoxy silanes.  
     
     
         5 . The solution of  claim 1  wherein the ratio of the amount of said epoxyalkylalkoxy silanes in said solution to the amount of said (math)acryloxyalkylalkoxy silanes in said solution is between 15 to 1 and 0.2 to 1.  
     
     
         6 . The solution of  claim 5  wherein said ratio is between 13 to 1 and 1 to 1.  
     
     
         7 . The solution of  claim 1  wherein the molar ratio of said water to the combination of said epoxyalkylalkoxy silanes and (math)acryloxyalkylalkoxy silanes is between 1 to 4 and 3 to 1.  
     
     
         8 . The solution of  claim 7  wherein said ratio is between 1 to 2 and 2to 1.  
     
     
         9 . The solution of  claim 1  including a curing agent present in an amount between 0.2 to 0.5 weight percent of said solution.  
     
     
         10 . The solution of  claim 9  wherein said curing agent is present in an amount between 0.3 to 0.4 weight percent of the solution.  
     
     
         11 . The solution of  claim 9  wherein said curing agent comprises one or more of titanium acetylacetonate, aluminum acetylacetonate, dibutyltin dilaurate and zinc napthenate.  
     
     
         12 . The solution of  claim 1  wherein said solvent comprises one or more of acetonitrile, acetone, methyl ethyl ketone, 2-heptanone, ethanol, isopropyl alcohol, n-butanol, iso-butanol, 2-ethoxyethanol and 2-butoxyethanol.  
     
     
         13 . The solution of  claim 1  wherein said tetraalkyl orthosilicate comprises one or more of tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate and tetrabutyl orthosilicate.  
     
     
         14 . The solution of  claim 1  wherein said (math)acryloxyalkylalkoxy silanes comprise one or more of 2-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 2-acryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 2-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 2-acryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltrimethoxysilane and methacryloxypropyltris(methoxyethoxy)methoxysilane.  
     
     
         15 . The solution of  claim 1  wherein said epoxyalkylalkoxy silanes comprise one or more of glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethyltriethoxysilane, 1-glycidoxyethyltrimethoxysilane, 1-glycidoxyethyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-glycidoxypropyltrimethoxysilane, 2-glycidoxypropyltriethoxysilane, 1-glycidoxypropyltrimethoxysilane, 2-glycidoxypropyltriethoxysilane, 4-glycidoxybutyltrimethoxysilane, 4-glycidoxybutyltriethoxysilane, 3-glycidoxybutyltrimethoxysilane, 2-glycidoxybutyltrimethoxysilane, 2-glycidoxybutyltriethoxysilane, 1-glycidoxybutyltrimethoxysilane, 1-glycidoxybutyltriethoxysilane, (3,4-epoxycyclohexyl)methyltrimethoxysilane. (3,4-epoxycyclohexyl)methyltriethoxysilane, glycidoxymethylmethyldimethoxysilane, glycidoxymethylmethyldiethoxysilane, 2-glycidoxyethylmethyldimethoxysilane, 2-glycidoxyethylmethyldiethoxysilane, 1-glycidoxyethylmethyldimethoxysilane, 1-glycidoxyethylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-glycidoxypropylmethyldimethoxysilane, 2-glycidoxypropylmethyldiethoxysilane, 1-glycidoxypropylmethyldimethoxysilane, 1-glycidoxypropylmethyldiethoxysilane, 4-glycidoxybutylmethyldimethoxysilane, 4-glycidoxybutylmethyldiethoxysilane, 3-glycidoxybutylmethyldimethoxysilane, 3-glycidoxybutylmethyldiethoxysilane, 2-glycidoxybutylmethyldimethoxysilane, 2-glycidoxybutylmethyldiethoxysilane, 1-glycidoxybutylmethyldimethoxysilane, 1-glycidoxybutylmethyldiethoxysilane, (3,4-epoxycyclohexyl)methylmethyldimethoxysilane, and (3,4-epoxycyclohexyl)methylmethyldiethoxysilane.  
     
     
         16 . The solution of  claim 1  wherein said tetraalkyl orthosilicate, said epoxyalkylalkoxy silanes and said (math)acryloxyalkylalkoxy silanes together comprise a polymerizable component that is 20-50 weight percent of said solution, said tetraalkyl orthosilicate being present in an amount greater than said epoxyalkylalkoxy silanes, and said epoxyalkylalkoxy silanes being present in an amount greater than said (math)acryloxyalkylalkoxy silanes.  
     
     
         17 . The solution of  claim 16  wherein said tetraalkyl orthosilicate is 40-75 weight percent of said polymerizable component, said epoxyalkylalkoxy silanes is 20-45 weight percent of said polymerizable component and said (math)acryloxyalkylalkoxy silanes is 5-15 weight percent of said polymerizable component.  
     
     
         18 . The solution of  claim 1  wherein 0.1-0.5 weight percent of said solution is 2M HCl and 0.5-2.0 weight percent of said solution is acetic acid.  
     
     
         19 . A curable coating solution for applying optically clear protective thin films to substrate surfaces, said coating solution having a polymerizable component that is 20-50 weight percent of the total solution and consists essentially of tetraalkyl orthosilicate, epoxyalkylalkoxy silanes and (math)acryloxyalkylalkoxy silanes.  
     
     
         20 . The solution of  claim 19  wherein said tetraalkyl orthosilicate is 40-75 weight percent of said polymerizable component, said epoxyalkylalkoxy silanes is 20-45 weight percent of said polymerizable component and said (math)acryloxyalkylalkoxy silanes is 5-15 weight percent of said polymerizable component.  
     
     
         21 . The solution of  claim 19  wherein 0.1-0.5 weight percent of said solution is 2M HCl and 0.5-2.0 weight percent of said solution is acetic acid.  
     
     
         22 . The solution of  claim 21  wherein 0.01-1.0 weight percent of said solution is a wetting agent and 0.2-0.5 weight percent of said solution is a curing agent.  
     
     
         23 . The solution of  claim 22  wherein the remainder of said solution is solvent and 20-50 weight percent of the solvent is water, the remainder of the solvent being one or more of alcohols and organic solvents.  
     
     
         24 . An optically clear protective film having organic polymer and generated silica molecules chemically bonded together by covalent bonds, said film having pores smaller than five angstroms.  
     
     
         25 . The film of  claim 24  wherein said film is bonded to a plastic substrate surface and said film suffers no visible crazing after undergoing a Boiling Salt Water Test or a Thermal Test.  
     
     
         26 . The film of  claim 25  wherein said plastic substrate surface is on a plastic substrate selected from polycarbonate, high index or CR-39.  
     
     
         27 . The film of  claim 26  wherein said plastic substrate is an eyeglass lens.  
     
     
         28 . The film of  claim 25  wherein said plastic substrate surface is on a plastic substrate selected from polycarbonate or high index, and a primer layer interposed between said film and said substrate surface.  
     
     
         29 . The film of  claim 24  including an antireflective coating bonded to said film.  
     
     
         30 . The film of  claim 29  including an hydrophobic film of amphiphillic molecules bonded to said antireflective coating.  
     
     
         31 . The film of  claim 24  wherein said film has a thickness not greater than 7 μm.  
     
     
         32 . A plastic substrate having a thin film bonded thereto, said thin film having organic polymer and generated silica molecules chemically bonded together by covalent bonds, and said film having a thickness not greater than 7 μm.  
     
     
         33 . The substrate of  claim 32  wherein said substrate is a plastic eyeglass lens selected from polycarbonate, high index or CR-39.  
     
     
         34 . The substrate of  claim 33  including an antireflective coating bonded to said film.  
     
     
         35 . The substrate of  claim 34  including an optically clear hydrophobic film of amphiphillic molecules bonded to said thin film.  
     
     
         36 . The substrate of  claim 32  wherein said substrate is a plastic eyeglass lens selected from polycarbonate or high index, and a primer layer interposed between said lens and said thin film.  
     
     
         37 . A method of providing a protective thin film on ophthalmic lenses comprising the steps of: 
 preparing a coating solution by mixing together tetraalkyl orthosilicate, epoxyalkylalkoxy silanes, (math)acryloxyalkylalkoxy silanes, solvent, HCl and acetic acid;    stirring the solution to partially hydrolyze the silane groups;    heating the solution while continuing to stir to completely hydrolyze the silane groups;    cooling the solution followed by dissolving a wetting agent and a catalyst in the solution;    applying a coating of the solution to a substrate surface; and    heating the substrate to cure the coating and bond same to the substrate surface as a protective thin film in which polymer and silica molecules are chemically bonded together by covalent bonds.    
     
     
         38 . The method of  claim 37  wherein said step of heating the substrate to cure the coating is carried out at a temperature of 90-120° C. for 30-60 minutes.  
     
     
         39 . The method of  claim 37  wherein said step of applying a coating of the solution to a substrate surface is carried out by applying the coating to an eyeglass lens of a material selected from polycarbonate, high index or CR-39.  
     
     
         40 . The method of  claim 37  including the step of applying a primer layer to the substrate surface prior to said step of applying a coating of the solution thereto.  
     
     
         41 . The method of  claim 37  including the step of applying an antireflective coating to said protective thin film.  
     
     
         42 . The method of claim  41  including the step of applying an hydrophobic film of amphiphillic molecules to said antireflective coating.  
     
     
         43 . The method of  claim 37  wherein said step of applying a coating of the solution to a substrate is carried out by applying a solution coating that provides a cured protective thin film having a thickness not greater than 7 μm.