Anti-reflective, abrasion resistant, anti-fogging coated articles and methods

• US 5,846,650 A
• Filed: 05/10/1996
• Issued: 12/08/1998
• Est. Priority Date: 05/10/1996
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Fung, Simon S., Ko, John H.
• Primary Examiner(s): Clardy, S. Mark
• Assistant Examiner(s): Williamson, Michael A.
• Application Number:
  US08/644,136
• Time in Patent Office: 942 Days
• Field of Search: 428/36.91, 428/35.7, 428/35.2, 428/34.6, 428/34.7, 428/421, 428/422, 428/425.6, 428/423.1, 428/336, 428/483, 428/412, 428/442, 381/41, 381/44, 381/49, 381/62, 381/159, 296/84.1, 427/162, 427/163.1
• US Class Current: 428/336
• CPC Class Codes: G02B 1/113 using inorganic layer materials only
• CPC Class Codes: G02B 1/14 Protective coatings, e.g. hard coatings
• CPC Class Codes: G02B 1/18 Coatings for keeping optical surfaces clean, e.g. hydrophobic or photo-catalytic films G02B1/16 takes precedence
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/31507 Of polycarbonate
• 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 428/31649 Ester, halide or nitrile of addition polymer
• CPC Class Codes: Y10T 428/31797 Next to addition polymer from unsaturated monomers

Abstract

An article comprising substrate having a surface and a coating on the surface of the substrate, the coating comprising a fluoropolymer and a fluorochemical surfactant. The fluoropolymer and the fluorochemical surfactant are selected such that the article is anti-reflective, abrasion resistant and anti-fogging. Methods of making the same are also described.

Claims

1. An article comprising an optically transparent substrate having a surface and a coating on the surface of the substrate, said coating comprising a fluoropolymer and a fluorochemical surfactant, said fluoropolymer and fluorochemical surfactant being selected such that the coated article is anti-reflective, abrasion resistant and anti-fogging.

2. The article of claim 1 wherein the fluoropolymer comprises the cross-linked polymerization product of a polyether fluoropolymer having functional end groups available for cross-linking and at least one fluorinated ene-functional reactant.

3. The article of claim 2 wherein the polyether fluoropolymer is selected from the group consisting of perfluoropolyether urethane dimethacrylates and perfluoropolyether diacrylates, and wherein the fluorinated ene-functional reactant comprises fluorinated cyclohexyl methyl acrylate monomer.

4. The article of claim 1 wherein the fluoropolymer comprises a thermoplastic fluoropolymer and the cross-linked polymerization product of at least one fluorinated ene-functional reactant.

5. The article of claim 4 wherein the thermoplastic fluoropolymer comprises a copolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride, and wherein the fluorinated ene-functional reactant comprises fluorinated cyclohexyl methyl acrylate.

6. The article of claim 1 wherein the article comprises a face shield.

7. The article of claim 1 wherein the article comprises protective eyeglasses.

8. The article of claim 1 wherein the article comprises a computer monitor screen.

9. The article of claim 1 wherein the coating has a thickness of about one quarter wavelength with respect to incident visible light and a refractive index of about the square root of the refractive index of the substrate.

10. The article of claim 1 wherein the coating has a thickness of approximately 1000-2000 angstroms.

11. The article of claim 1 wherein the coating has a thickness of about one quarter wavelength with respect to incident ultraviolet radiation and a refractive index of about the square root of the refractive index of the substrate.

12. The article of claim 1 wherein the coating has a thickness of about 400-1000 angstroms.

13. The article of claim 1 wherein the coating has a thickness of about one quarter wavelength with respect to incident infrared radiation and a refractive index of about the square root of the refractive index of the substrate.

14. The article of claim 1 wherein the coating has a thickness of between about 2000-2500 angstroms.

15. The article of claim 1 wherein the substrate comprises polyethylene terephthalate film.

16. The article of claim 1 wherein the substrate comprises polycarbonate film.

17. The article of claim 1 wherein the substrate comprises a high refractive index glass.

18. The article of claim 1 wherein the fluoropolymer comprises a thermoplastic fluoropolymer, and the coating further comprises an additional thermoplastic polymer different from said thermoplastic fluoropolymer, said additional thermoplastic polymer being selected to enhance the abrasion resistance of the coated article and to enhance adhesion of the coating to the surface of the substrate.

19. The article of claim 18 wherein the additional thermoplastic polymer comprises polymethyl methacrylate.

20. The article of claim 1 wherein the coated article exhibits improved light transmission at 500 nanometers of at least 2 percent compared with uncoated substrate.

21. The article of claim 1 wherein the coated article exhibits an Abrasion Test 2 score of about 10 cycles or greater.

22. The article of claim 1 wherein the coated article exhibits an anti-fogging test score of 0.

23. A method of imparting anti-reflective, abrasion resistance, and anti-fogging properties to an optically clear substrate, the method comprising the steps of:

providing a substrate having a surface;

providing a coating composition on the surface of the substrate, the coating composition comprising a fluoropolymer and a fluorochemical surfactant; and

causing the coating composition to harden on the surface of the substrate;

said fluoropolymer and fluorochemical surfactant being selected such that the substrate coated with the coating composition is anti-reflective, abrasion resistant, and anti-fogging.

24. The method of claim 23 wherein the fluoropolymer comprises a polyether fluoropolymer having functional end groups available for cross-linking, and wherein the coating composition further comprises at least one fluorinated ene-functional reactant.

25. The method of claim 24 wherein the coating composition comprises a photoinitiator and wherein the step of causing the coating composition to harden on the surface of the substrate comprises curing the coating composition on the surface of the substrate to produce a hardened coating on the surface of the substrate comprising the cross-linked polymerization product of the polyether fluoropolymer and at least one fluorinated ene-functional reactant.

26. The method of claim 23 wherein the fluoropolymer comprises a thermoplastic fluoropolymer.

27. The method of claim 26 wherein the coating composition further comprises at least one fluorinated ene-functional reactant.

28. The method of claim 27 wherein step of causing the coating composition to harden comprises curing the coating composition on the surface of the substrate to produce a coating on the surface of the substrate comprising the thermoplastic fluoropolymer and the cross-linked polymerization product of at least one fluorinated ene-functional reactant.

29. The method of claim 26 wherein the coating composition further comprises an additional thermoplastic polymer different from said thermoplastic fluoropolymer, said additional thermoplastic fluoropolymer being selected to enhance adhesion resistance of the coated article and to enhance adhesion of the coating to the surface of the substrate.

30. The method of claim 29 wherein step of causing the coating composition to harden on the surface of the substrate comprises drying the coating composition on the surface of the substrate.