Low refractive index fluoropolymer compositions having improved coating and durability properties

Abstract

A low refractive index composition that forms a low refractive index layer on an optical display is formed having a co-crosslinked interpenetrating polymer network of a fluoropolymer phase and an acrylate phase. The fluoropolymer phase is preferably formed from fluoropolymers based on THV or FKM and having either a degree of unsaturation and/or containing a reactive cure site monomer in its polymer backbone. The acrylate phase includes a multifunctional acrylate crosslinker, and more preferably includes a perfluoropolyether acrylate crosslinker. The formed low refractive index layer has improved interfacial adhesion to other layers or substrates contained in the optical display. Further, the mechanical strength and scratch resistance of the either of above low refractive index compositions can be further enhanced through the incorporation of surface functionalized inorganic particle into the formed layer.

1 . A low refractive index material for use in an antireflective coating for an optical display, the low refractive index material comprising the reaction product of: 
 a functional fluoropolymer phase comprising a fluoropolymer having a small portion of unsaturation; and    an acrylate phase, said fluoropolymer phase and said multifunctional acrylate phase reacting to form a co-crosslinked interpenetrating polymer network.    
   
   
       2 . The low refractive index material of  claim 1 , wherein said functional fluoropolymer phase comprises an amorphous fluoropolymer composition having a small portion of unsaturation.  
   
   
       3 . The low refractive index of  claim 2 , wherein said functional fluoropolymer phase further comprises a crystalline fluoropolymer composition.  
   
   
       4 . The low refractive index of  claim 2 , wherein said functional fluoropolymer phase further comprises a crystalline fluoropolymer composition having a small portion of unsaturation.  
   
   
       5 . The low refractive index material of  claim 2 , wherein said amorphous fluoropolymer composition having a small portion of unsaturation comprises an amorphous fluoropolymer composition having a small portion of unsaturation and further having interpolymerized units derived from vinylidene fluoride and hexafluoropropylene.  
   
   
       6 . The low refractive index material of  claim 2 , wherein said amorphous fluoropolymer composition having a small portion of unsaturation comprises a THE copolymer having a small portion of unsaturation.  
   
   
       7 . The low refractive index material of  claim 2 , wherein said amorphous fluoropolymer composition comprises an amorphous fluoropolymer composition having at least one reactive cure site monomer and having a small portion of unsaturation.  
   
   
       8 . The low refractive index material of  claim 2 , wherein said amorphous fluoropolymer composition comprises an amorphous fluoropolymer composition having a halogen-containing cure site monomer and having a small portion of unsaturation.  
   
   
       9 . The low refractive index material of  claim 2 , wherein said amorphous fluoropolymer composition having a small portion of unsaturation comprises a VDF-chlorotrifluoroethylene copolymer having a small portion of unsaturation.  
   
   
       10 . The low refractive index material of  claim 1 , wherein said functional fluoropolymer phase comprises a crystalline fluoropolymer composition having a small portion of unsaturation.  
   
   
       11 . The low refractive index material of  claim 10 , wherein said crystalline fluoropolymer composition comprises THV having a small portion of unsaturation.  
   
   
       12 . The low refractive index material of  claim 10 , wherein said crystalline fluoropolymer composition having a small portion of unsaturation comprises a crystalline fluoropolymer composition having a small portion of unsaturation and having at least one reactive cure site monomer.  
   
   
       13 . The low refractive index material of  claim 10 , wherein said crystalline fluoropolymer composition having a small portion of unsaturation comprises a halogen-containing crystalline fluoropolymer composition having a small portion of unsaturation.  
   
   
       14 . The low refractive index material of  claim 1 , wherein said low refractive index composition further comprises a plurality of surface modified inorganic nanoparticles.  
   
   
       15 . The low refractive index material of  claim 14 , wherein said plurality of surface modified inorganic nanoparticles comprises a plurality of surface modified silica particles.  
   
   
       16 . The low refractive index material of  claim 1 , wherein said acrylate phase comprises a multifunctional acrylate crosslinker composition.  
   
   
       17 . The low refractive index material of  claim 16 , wherein said multifunctional acrylate crosslinker composition comprises trimethylolpropane triacrylate.  
   
   
       18 . The low refractive index material of  claim 16 , wherein said multifunctional acrylate crosslinker composition comprises pentaerythritol tri/tetraacrylate.  
   
   
       19 . The low refractive index material of  claim 16 , wherein said multifunctional acrylate crosslinker composition comprises dipentaerythritol pentaacrylate.  
   
   
       20 . The low refractive index material of  claim 1 , wherein said acrylate phase comprises a fluorinated acrylate composition.