Low refractive index fluoropolymer compositions having improved coating and durability properties
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. An antireflection film comprising:
a high refractive index layer; and
a low refractive index layer comprising the reaction product of a functional fluoropolymer phase reacted with a multifunctional acrylate phase to form a co-crosslinked interpenetrating polymer network, wherein the functional fluoropolymer consists essentially of at least two constituent monomers selected from of TFE, VDF, and HFP; and the functional fluoropolymer has reactive functionality from at least one halogen containing cure site monomer, 0.5 to 6 mole percent of unsaturations in the fluoropolymer backbone, or a combination thereof.
2. The antireflective film of claim 1 wherein the functional fluoropolymer has reactive functionality from 0.5 to 6 mole percent of unsaturations in the fluoropolymer backbone.
3. The antireflection film of claim 1 , wherein the functional fluoropolymer has reactive functionality from and at least one halogen containing cure site monomer.
4. The antireflection film of claim 1 , wherein the functional fluoropolymer has reactive functionality from 0.5 to 6 mole percent of unsaturations in the fluoropolymer backbone and and at least one halogen containing cure site monomer.
5. The antireflection film of claim 1 , wherein said functional fluoropolymer comprises an amorphous fluoropolymer.
6. The antireflection film of claim 5 , wherein the functional fluoropolymer consists of interpolymerized units derived from at least HFP and VDF.
7. The antireflection film of claim 5 , wherein said functional fluoropolymer phase further comprises a crystalline fluoropolymer composition.
8. The antireflection film of claim 1 , wherein said multiacrylate phase comprises 10 wt-% to 50 wt-% of multifunctional acrylate crosslinker.
9. The antireflection film of claim 1 , wherein the multifunctional acrylate crosslinker comprises at least three (meth)acrylate functional groups.
10. The antireflection film of claim 1 , wherein said low refractive index composition further comprises a plurality of surface modified inorganic nanoparticles.
11. The antireflection film of claim 10 , wherein said plurality of surface modified inorganic nanoparticles comprises a plurality of surface modified silica particles.
12. The antireflection film of claim 1 , wherein said multiacrylate phase comprises a fluorinated acrylate composition.
13. The antireflection film of claim 12 , wherein said fluorinated acrylate is a perfluoropolyether acrylate composition.
14. The antireflection film of claim 13 , wherein said perfluoropolyether acrylate composition is selected from the group consisting of a HFPO-monoacrylate composition and a HFPO-multi-acrylate composition.
15. An optical device comprising said antireflection film formed according to claim 1 .