Antireflective coating compositions and methods for depositing such coatings

Abstract

Coating compositions, and methods for depositing them on the surface of an article to produce an antireflection coating, are disclosed. In one embodiment, the coating composition includes a (meth)acrylate-functional silicon alkoxide, silica particles, a (meth)acrylate monomer, an epoxy(meth)acrylate oligomer, a photoinitiator, a solvent, an acid, and water. The relative amounts of these constituents are controlled such that, when the coating composition is deposited onto the surface of an article and cured, it has a refractive index less than about 1.60 at a wavelength of 510 nm. In another embodiment, the coating composition includes an organo-metallic compound other than an organo-metallic compound of silicon, an epoxy-functional silicon alkoxide, a non-epoxy-functional silicon alkoxide, a curing agent compatible with epoxy-functional molecules, a solvent, an inorganic acid, and water. The relative amounts of these constituents are controlled such that, when the coating composition is deposited onto the surface of an article and cured, it has a refractive index greater than about 1.70 at a wavelength of 510 nm. The coating compositions are deposited in a process that produces an antireflection coating in less than 90 minutes of processing time.

1 . A coating process comprising the steps of: 
 forming an antireflection coating on a surface of an article, wherein the step of forming includes a step of depositing a first coating layer onto the surface of the article by using a first coating composition that comprises at least one (meth)acrylate-functional silicon alkoxide, silica particles, at least one (meth)acrylate monomer, at least one epoxy (meth)acrylate oligomer, at least one photoinitiator, at least one solvent, at least one acid, and water, wherein the step of depositing the first coating layer includes 
 dispensing the first coating composition onto the surface of the article, and  
 curing the dispensed first coating composition, to produce the first coating layer,  
 wherein the first coating layer has a refractive index less than about 1.60 at a wavelength of 510 nm;  
   wherein the step of forming an antireflection coating has a time duration of less than 90 minutes,    and wherein the antireflection coating has prescribed optical properties and prescribed adhesion and abrasion resistance properties.    
     
     
         2 . A coating process as defined in  claim 1 , wherein the step of forming has a time duration of less than 30 minutes.  
     
     
         3 . A coating process as defined in  claim 1 , wherein the step of forming has a time duration of less than 10 minutes.  
     
     
         4 . A coating process as defined in  claim 1 , wherein the first coating layer deposited in the step of depositing has a refractive index less than about 1.55 at a wavelength of 510 nm.  
     
     
         5 . A coating process as defined in  claim 1 , wherein the first coating layer deposited in the step of depositing has a refractive index less than about 1.50 at a wavelength of 510 nm.  
     
     
         6 . A coating process as defined in  claim 1 , wherein: 
 the step of forming further includes a step of depositing a second coating layer onto the surface of the article by using a second coating composition that comprises at least one organo-metallic compound other than an organo-metallic compound of silicon, at least one epoxy-functional silicon alkoxide, at least one non-epoxy-functional silicon alkoxide, at least one curing agent compatible with epoxy-functional molecules, at least one solvent, at least one inorganic acid, and water, wherein the step of depositing the second coating layer includes 
 dispensing the second coating composition onto the surface of the article, and  
 curing the dispensed second coating composition, to produce the second coating layer,  
 wherein the second coating layer has a refractive index greater than about 1.70 at a wavelength of 510 nm.  
   
     
     
         7 . A coating process as defined in  claim 6 , wherein the second coating layer has a refractive index greater than about 1.80 at a wavelength of 510 nm.  
     
     
         8 . A coating process as defined in  claim 6 , wherein the second coating layer has a refractive index greater than about 1.90 at a wavelength of 510 nm.  
     
     
         9 . A coating process as defined in  claim 6 , wherein the step of depositing the second coating layer occurs before the step of depositing the first coating layer.  
     
     
         10 . A coating process as defined in  claim 6 , wherein the step of depositing the second coating layer alternates with the step of depositing the first coating layer, to produce an antireflection coating having at least four layers.  
     
     
         11 . A coating process as defined in  claim 10 , wherein at least one of the alternating steps of depositing the second coating layer and depositing the first coating layer includes a step of heat-treating the dispensed coating composition prior to the step of curing such dispensed coating composition.  
     
     
         12 . A coating process as defined in  claim 1 , and further comprising a step of depositing a hard-coat layer onto the surface of the article prior to the step of forming the antireflection coating.  
     
     
         13 . A coating composition comprising 
 at least one (meth)acrylate-functional silicon alkoxide, silica particles, at least one (meth)acrylate monomer, at least one epoxy(meth)acrylate oligomer, at least one photoinitiator, at least one solvent, at least one acid, and water;    wherein the relative amounts of the constituents of the coating composition are controlled such that, when the coating composition is dispensed onto the surface of an article and cured, it has a refractive index less than about 1.60 at a wavelength of 510 nm.    
     
     
         14 . A coating composition as defined in  claim 13 , wherein the at least one (meth)acrylate-functional silicon alkoxide is selected from the group consisting of (3-acryloxypropyl)dimethylmethoxysilane, (3-acryloxypropyl)methlyldimethoxysilane, (3-acryloxypropyl)trimethoxysilane, (methacryloxymethyl)dimethylethoxysilane, methacryloxymethyltriethoxysilane, methacryloxymethyltrimethoxysilane, methacryloxypropylmethyldiethoxysilane, methacryloxypropylmethyldimethoxysilane, (3-methacryloxypropyl)triethoxysilane, (3-methacryloxypropyl)trimethoxysilane, and mixtures thereof.  
     
     
         15 . A coating composition as defined in  claim 13 , wherein the at least one (meth)acrylate-functional silicon alkoxide is (3-acryloxypropyl)trimethoxysilane.  
     
     
         16 . A coating composition as defined in  claim 13 , wherein the at least one (meth)acrylate monomer is selected from the group consisting of 2(2-ethoxyethoxy)ethyl acrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, caprolactone acrylate, dicyclopentadienyl methacrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, 1,3-butylene glycol diacrylate, 1,4 butanediol dimethacrylate, diethylene glycol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, ethylene glycol dimethacrylate, ethoxylated trimethylolpropane triacrylate, pentaeryhritol triacrylate, propoxylated glyceryl triacrylate, propoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, tris(2-hydroxy ethyl) isocyanurate triacrylate, and mixtures thereof.  
     
     
         17 . A coating composition as defined in  claim 13 , wherein the at least one (meth)acrylate monomer is selected from the group consisting of ethoxylated trimethylolpropane triacrylate, tris(2-hydroxy ethyl) isocyanurate triacrylate, and mixtures thereof.  
     
     
         18 . A coating composition as defined in  claim 13 , wherein the at least one (meth)acrylate monomer is a mixture of ethoxylated trimethylolpropane triacrylate and tris(2-hydroxy ethyl) isocyanurate triacrylate.  
     
     
         19 . A coating composition as defined in  claim 13 , wherein the at least one photoinitiator is selected from the group consisting of 1-hydroxy-cyclohexyl-phenyl-ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, and mixtures thereof.  
     
     
         20 . A coating composition as defined in  claim 13 , wherein the at least one photoinitiator is a mixture of 1-hydroxy-cyclohexyl-phenyl-ketone and 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone.  
     
     
         21 . A coating composition as defined in  claim 13 , wherein the at least one solvent is selected from the group consisting of isopropanol, ethyl acetate, 1-methoxy 2-propanol, and mixtures thereof.  
     
     
         22 . A coating composition as defined in  claim 13 , wherein the at least one solvent is a mixture of isopropanol, ethyl acetate, and 1-methoxy 2-propanol.  
     
     
         23 . A coating composition as defined in  claim 13 , wherein the at least one inorganic acid is hydrochloric acid.  
     
     
         24 . A coating composition as defined in  claim 13 , wherein the relative amounts of the constituents of the coating composition are controlled such that, when the composition is deposited onto the surface of an article and cured, it has a refractive index less than about 1.55 at a wavelength of 510 nm.  
     
     
         25 . A coating composition as defined in  claim 13 , wherein the relative amounts of the constituents of the coating composition are controlled such that, when the composition is deposited onto the surface of an article and cured, it has a refractive index less than about 1.50 at a wavelength of 510 nm.  
     
     
         26 . A coating composition comprising 
 at least one organo-metallic compound other than an organo-metallic compound of silicon, at least one epoxy-functional silicon alkoxide, at least one non-epoxy-functional silicon alkoxide, at least one curing agent compatible with epoxy-functional molecules, at least one solvent, at least one inorganic acid, and water;    wherein the relative amounts of the constituents of the coating composition are controlled such that, when the coating composition is dispensed onto the surface of an article and cured, it has a refractive index greater than about 1.70 at a wavelength of 510 nm.    
     
     
         27 . A coating composition as defined in  claim 26 , wherein the at least one organo-metallic compound is selected from the group consisting of organo-metallic compounds represented by formulas R 1   x M 1  (OR 2 ) 4-x , R 1   y M 2 (OR 2 ) 3-y , R 1   z Nb(OR 2 ) 5-z , and mixtures thereof; 
 wherein M 1  is a metal selected from the group consisting of Ti, Zr, Ge, and Sn;    wherein M 2  is a metal selected from the group consisting of Al, In, and Sb;    wherein R 1  is an organic functional group selected from the group consisting of C 1 -C 4  alkyl, vinyl, allyl, acryloxy, epoxide, and amino groups;    wherein R 2  is C 1 -C 4  alkyl group; and    wherein x is 0, 1, 2, or 3; y is 0, 1, or 2; and z is 0, 1, 2, 3, or 4.    
     
     
         28 . A coating composition as defined in  claim 26 , wherein the at least one organo-metallic compound is titanium isopropoxide.  
     
     
         29 . A coating composition as defined in  claim 26 , wherein the at least one epoxy-functional silicon alkoxide is selected from the group consisting of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 5,6-epoxyhexyltriethoxysilane, (3-glycidoxypropyl)dimethylethoxysilane, (3-glycidoxypropyl)methyldiethoxysilane, glycidoxypropyl)methyldimethoxysilane, (3-glycidoxypropyl)trimethoxysilane, glycidoxymethyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-cyanopropyltrimethoxysilane, and mixtures thereof.  
     
     
         30 . A coating composition as defined in  claim 26 , wherein the at least one epoxy-functional silicon alkoxide is (3-glycidoxypropyl)trimethoxysilane.  
     
     
         31 . A coating composition as defined in  claim 26 , wherein the at least one non-epoxy-functional silicon alkoxide is represented by a general formula (OFG) w -Si—(OR 3 ) 4-w , wherein OFG is an organofunctional group; OR 3  is a hydrolyzable alkoxy group; R 3  is an alkyl; and w is 0, 1, 2 or 3.  
     
     
         32 . A coating composition as defined in  claim 26 , wherein the at least one non-epoxy-functional silicon alkoxide is selected from the group consisting of tetraethoxysilane, tetramethoxysilane, and mixtures thereof.  
     
     
         33 . A coating composition as defined in  claim 26 , wherein the at least one non-epoxy-functional silicon alkoxide is a mixture of tetraethoxysilane and tetramethoxysilane.  
     
     
         34 . A coating composition as defined in  claim 26 , wherein the at least one curing agent is selected from the group consisting of an anhydride, a carboxylic acid, and mixtures thereof.  
     
     
         35 . A coating composition as defined in  claim 26 , wherein at least one curing agent is selected from the group consisting of acetic anhydride, acrylic anhydride, cyclic anhydride, hexahydrophthalic anhydride, methacrylic anhydride, propionic anhydride, acetic acid, acrylic acid, formic acid, fumiaic acid, itaconic acid, maleic acid, methacrylic acid, propionic acid, methylenesuccinic acid, and mixtures thereof.  
     
     
         36 . A coating composition as defined in  claim 26 , wherein the at least one curing agent is hexahydrophthalic anhydride.  
     
     
         37 . A coating composition as defined in  claim 26 , wherein the at least one curing agent is methylenesuccinic acid.  
     
     
         38 . A coating composition as defined in  claim 26 , wherein the at least one solvent is selected from the group consisting of ethanol, 1-methoxy 2-propanol, and mixtures thereof.  
     
     
         39 . A coating composition as defined in  claim 26 , wherein the at least one solvent is a mixture of ethanol and 1-methoxy 2-propanol.  
     
     
         40 . A coating composition as defined in  claim 26 , wherein the at least one inorganic acid is hydrochloric acid.  
     
     
         41 . A coating composition as defined in  claim 26 , wherein the relative amounts of the constituents of the coating composition are controlled such that, when the composition is dispensed onto the surface of an article and cured, it has a refractive index greater than about 1.80 at a wavelength of 510 nm.  
     
     
         42 . A coating composition as defined in  claim 26 , wherein the relative amounts of the constituents of the coating composition are controlled such that, when the composition is dispensed onto the surface of an article and cured, it has a refractive index greater than about 1.90 at a wavelength of 510 nm.