Preparation of a mechanically durable single layer coating with anti-reflective properties

Abstract

Single layer anti-reflective hard-coat; in particular which comprises a structured surface, preferably a nano-structured surface. The hard-coat preferably a hardness above 0.5 GPa, more preferably above 0.7 GPa and most preferably above 1.0 GPa as measured by nano-indentation and/or a reduced tensile modulus above 3 GPa, more preferably above 8.5 GPa or 20 GPa, most preferably above 40 GPa as measured by nano-indentation and/or a scratch resistance above 5 mJ μm −3 , preferably above 15 or 30 mJ μm −3 , preferably above 60 mJ μm −3 as measured by nano-indentation, and/or contains an amount of inorganic nano-particles from 5 to 75 weight %, preferably from 15 to 50 weight % relative to the weight of the second material present in the hard-coat. Preferably, the spatial length scale of the refractive index gradient in the single layer hard-coat is between 10 and 1000 nm; in particular between 100 and 200 nm. Also concerned is a process for preparing a single layer hard-coat, comprising the steps of a) applying a mixture on a substrate, which mixture comprises i. at least a first material which does not crosslink under the conditions chosen in step b) ii. at least a second material which does crosslink under the conditions chosen in step b) iii. nano-particles, and iv. optionally at least one solvent b) inducing crosslinking in the mixture applied to the substrate, v. subsequently removing at least part of the first material, and shaped articles comprising such single layer hard-coat.

1 - 12 . (canceled) 
   
   
       13 . A process for preparing a single layer hard-coat, comprising the steps of
 a) applying a mixture on a substrate, which mixture comprises
 i. at least a first material which does not crosslink under the conditions chosen in step b) 
 ii. at least a second material which does crosslink under the conditions chosen in step b) 
 iii. nano-particles, and 
 iv. optionally at least one solvent 
   b) inducing crosslinking in the mixture applied to the substrate, subsequently removing at least part of the first material.   
   
   
       14 . A process according to  claim 13  wherein the mixture is homogenous prior to crosslinking. 
   
   
       15 . A process according to  claim 13  wherein at least part of the nano-particles have organic groups on their surface. 
   
   
       16 . A process according to  claim 13 , wherein the nano-particles are inorganic nano-particles. 
   
   
       17 . A process according to  claim 13 , wherein the monomer or oligomer present in the second material has at least two and preferably three or more reactive/polymerizable or crosslinkable groups per monomer or oligomer molecule. 
   
   
       18 . A process according to  claim 13  wherein the majority of the nano-particles have a diameter of less than 400 nm. 
   
   
       19 . (canceled) 
   
   
       20 . A process according to  claim 13  wherein the majority of the nano-particles have a diameter of less than 50 nm.