Low refractive index fluoropolymer compositions having improved coating and durability properties

• US 7,473,462 B2
• Filed: 01/10/2008
• Issued: 01/06/2009
• Est. Priority Date: 12/30/2004
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Wang, Sharon, Moore, George G. I., Klun, Thomas P., Savu, Patricia M., Jing, Naiyong, Noyola, Joan M., Liu, Lan H., Cao, Chuntao, Coggio, William D.
• Primary Examiner(s): Zacharia; Ramsey
• Application Number:
  US11/972,034
• Publication Number:
  US 20080107907A1
• Time in Patent Office: 362 Days
• Field of Search: None
• US Class Current: 428/212
• CPC Class Codes: C08F 14/18 Monomers containing fluorine
• CPC Class Codes: C08F 2/00 Processes of polymerisation
• CPC Class Codes: C08F 259/08 on to polymers containing fluorine
• CPC Class Codes: C08F 283/00 Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 51/003 grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds C08L51/04, C08L51/06 take precedence
• CPC Class Codes: C09D 151/003 grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds C09D151/04, C09D151/06 take precedence
• CPC Class Codes: G02B 1/111 using layers comprising organic materials
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/259 Silicic material
• CPC Class Codes: Y10T 428/3154 Of fluorinated addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31544 Addition polymer is perhalogenated
• CPC Class Codes: Y10T 428/31935 Ester, halide or nitrile of addition polymer

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.

Claims

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.