Carbon Nanotube-Based Curable Coating Composition Providing Antistatic Abrasion-Resistant Coated Articles

Abstract

The present invention relates to a curable composition, providing, upon curing, an abrasion-resistant, transparent, antistatic coating, comprising carbon nanotubes and a binder comprising at least one epoxysilane compound, preferably an epoxyalkoxysilane, and optionally fillers such as nanoparticles of non electrically conductive oxides and/or additional binder components such as tetraethoxysilane. The invention further relates to optical articles comprising a substrate, and, starting from the substrate, an abrasion- and/or scratch-resistant coating, and an antistatic coating formed by depositing directly onto said abrasion- and/or scratch-resistant coating the above referred curable composition. The obtained optical articles exhibit antistatic properties, high optical transparency with about 91-92% of transmittance, low haze and improved abrasion resistance.

1 - 21 . (canceled) 
     
     
         22 . A curable composition, providing, upon curing, an abrasion-resistant, transparent, low haze, antistatic coating, comprising:
 a) carbon nanotubes, and   b) a binder comprising at least one compound of formula:
   R n′ Y m Si(X) 4-n′-m    (I) 
   
       or a hydrolyzate thereof, in which the R groups are identical or different and represent monovalent organic groups linked to the silicon atom through a carbon atom, the Y groups are identical or different and represent monovalent organic groups linked to the silicon atom through a carbon atom and containing at least one epoxy function, the X groups are identical or different and represent hydrolyzable groups or hydrogen atoms, m and n′ are integers such that m is equal to 1 or 2 and n′+m=1 or 2. 
     
     
         23 . The curable composition of  claim 22 , wherein the Y groups are independently groups of formulae III and/or IV: 
       
         
           
           
               
               
           
         
       
       in which R 2  is an alkyl group or a hydrogen atom, a and c are integers ranging from 1 to 6, and b is 0, 1, or 2. 
     
     
         24 . The curable composition of  claim 22 , wherein the compound of formula I is an epoxytrialkoxysilane of formula V or VI: 
       
         
           
           
               
               
           
         
       
       in which R 1  is an alkyl group having 1 to 6 carbon atoms, a and c are integers ranging from 1 to 6, and b is 0, 1 or 2. 
     
     
         25 . The curable composition of  claim 22 , wherein the binder further comprises at least one compound of formula:
   R n Si(Z) 4-n    (II)   
       or a hydrolyzate thereof, in which the R groups are identical or different and represent monovalent alkyl groups, the Z groups are identical or different and represent hydrolyzable groups or hydrogen atoms, and n is an integer equal to 0, 1, or 2. 
     
     
         26 . The curable composition of  claim 22 , further comprising a filler. 
     
     
         27 . The curable composition of  claim 26 , wherein the filler comprises nanoparticles. 
     
     
         28 . The curable composition of  claim 27 , wherein the nanoparticles have a diameter ranging from 2 to 100 nm. 
     
     
         29 . The curable composition of  claim 28 , wherein the nanoparticles have a diameter ranging from 5 to 50 nm. 
     
     
         30 . The curable composition of  claim 27 , wherein the nanoparticles comprise at least one of Al 2 O 3 , TiO 2 , SiO 2 , ZrO 2 , Sb 2 O 5 , Ta 2 O 5 , SnO 2 , zinc oxide, indium Si 3 N 4 , and/or MgF 2 . 
     
     
         31 . The curable composition of  claim 26 , wherein the ratio of (theoretical dry extract weight of fillers)/(theoretical dry extract weight of the composition) is from 25 to 80%. 
     
     
         32 . The curable composition of  claim 22 , wherein the ratio of (theoretical dry extract weight of compound of formula I)/(theoretical dry extract weight of the composition) is from 20 to 100%. 
     
     
         33 . The curable composition of  claim 22 , wherein the ratio of (theoretical dry extract weight of compound of formula II)/(theoretical dry extract weight of the composition) is from 15 to 60%. 
     
     
         34 . The curable composition of  claim 22 , wherein the ratio of (weight of carbon nanotubes)/(theoretical dry extract weight of binder) is from 0.00025 to 0.01. 
     
     
         35 . The curable composition of  claim 22 , wherein the carbon nanotubes are present in an amount ranging from 0.002 to 0.015% based on the total weight of the composition. 
     
     
         36 . The curable composition of  claim 22 , wherein the composition comprises less than 1% by weight electrically conductive fillers based on the total weight of the composition. 
     
     
         37 . The curable composition of  claim 36 , wherein the composition comprises 0% by weight electrically conductive fillers based on the total weight of the composition. 
     
     
         38 . An optical article comprising a substrate, and, starting from the substrate:
 an abrasion- and/or scratch-resistant coating; and   an antistatic coating formed by depositing directly onto said abrasion- and/or scratch-resistant coating a curable composition of  claim 22 .   
     
     
         39 . The optical article of  claim 38 , wherein the thickness of the antistatic coating is from 50 nm to 2 μm. 
     
     
         40 . The optical article of  claim 38 , wherein the abrasion- and/or scratch-resistant coating is a (meth)acrylate based coating or silicon-containing coating. 
     
     
         41 . The optical article of  claim 38 , wherein the abrasion- and/or scratch-resistant coating has a thickness of at least 1 μm. 
     
     
         42 . The optical article of  claim 38 , further defined as a lens or lens blank. 
     
     
         43 . The optical article of  claim 38 , further defined as having a charge decay time ≦500 milliseconds. 
     
     
         44 . The optical article of  claim 38 , further defined as having a relative light transmission factor in the visible spectrum Tv higher than 90%. 
     
     
         45 . A process for preparing the optical article of  claim 38 , comprising:
 providing an optical article comprising a substrate;   applying onto the surface of the substrate an abrasion- and/or scratch-resistant coating;   depositing directly onto said abrasion- and/or scratch-resistant coating a curable composition of  claim 22 ; and   curing said composition.