Scratch resistant optical films and method for producing same

• US 5,900,287 A
• Filed: 10/31/1997
• Issued: 05/04/1999
• Est. Priority Date: 02/03/1995
• Status: Expired due to Term

• Current Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Original Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Inventors: Williams, Todd R.
• Primary Examiner(s): CAMERON, ERMA C
• Application Number:
  US08/961,978
• Time in Patent Office: 550 Days
• Field of Search: 427/510, 427/517, 427/272, 427/275, 427/282
• US Class Current: 427/510
• CPC Class Codes: B29D 11/00 Producing optical elements, e.g. lenses or prisms grinding or polishing of optical elements B24B; constructional form of optical elements G02B; optical parts of spectacles G02C7/00
• CPC Class Codes: B29K 2995/0087 Wear resistance
• CPC Class Codes: C09K 2323/03 Viewing layer characterised by chemical composition
• CPC Class Codes: G02B 1/111 using layers comprising organic materials
• CPC Class Codes: G02B 1/14 Protective coatings, e.g. hard coatings
• CPC Class Codes: G02B 5/0215 the surface having a regular structure
• CPC Class Codes: G02B 5/0231 the surface having microprismatic or micropyramidal shape macroscopic prism arrays G02B5/045
• CPC Class Codes: G02B 5/0268 characterized by the fabrication or manufacturing method
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/2457 Parallel ribs and/or grooves
• CPC Class Codes: Y10T 428/24612 Composite web or sheet
• CPC Class Codes: Y10T 428/31 Surface property or characteristic of web, sheet or block
• CPC Class Codes: Y10T 428/31533 Of polythioether
• CPC Class Codes: Y10T 428/31551 Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
• CPC Class Codes: Y10T 428/31573 Next to addition polymer of ethylenically unsaturated monomer
• CPC Class Codes: Y10T 428/31591 Next to cellulosic
• CPC Class Codes: Y10T 428/31601 Quartz or glass
• CPC Class Codes: Y10T 428/31725 Of polyamide
• CPC Class Codes: Y10T 428/31736 : Next to polyester
• CPC Class Codes: Y10T 428/31779 : Next to cellulosic
• CPC Class Codes: Y10T 428/31786 : Of polyester [e.g., alkyd, etc.]
• CPC Class Codes: Y10T 428/3179 : Next to cellulosic

Abstract

A film that exhibits increased scratch resistant characteristics. The film is formed from a layer of crosslinkable oligomeric resin composition on a base. The film is made by: forming the layer of crosslinkable oligomeric resin composition on the base, and curing the resin composition to an extent that the film exhibits a haze decrease of less than or equal to 60 percent after abrading according to the ASTM D-968-81 procedure using 200 milliliters of sand. Preferably, the layer has a microstructure of alternating tips and grooves. Such films are useful in backlit displays which are useful in computers and the like.

Claims

1. A method of producing an increased scratch resistant film disposed on a base from a crosslinkable oligomeric resin composition, the method comprising:

depositing the crosslinkable oligomeric resin composition on the base; and

curing the resin composition to an extent that the film exhibits a haze increase of less than or equal to 60 percent after abrasion according to ASTM D-968-81 procedure using 200 milliliters of sand.

2. The method of claim 1 wherein a microstructure of alternating tips and grooves are formed from the resin composition.

3. The method of claim 2 wherein the tips have an included angle in the approximate range of 70°

to 120°

.

4. The method of claim 1 wherein the oligomeric resin composition is formed into a flat film and the haze increase is less than or equal to 30 percent after abrasion according to ASTM D-968-81 procedure using 200 milliliters of sand.

5. The method of claim 1 wherein the crosslinkable oligomeric resin composition forms a polymer having a tensile modulus of less than 6.8×

10⁸ pascals when evaluated according to ASTM D-882-91 procedure.

6. The method of claim 1 wherein the oligomeric composition forms a polymer which exhibits an elongation at break of greater than 50 percent when evaluated according to ASTM D-882-91 procedure.

7. The method of claim 1 wherein the crosslinkable oligomeric resin composition comprises at least one resin selected from the group consisting of acrylate or thioacrylate terminated polythioether oligomer, acrylated polysulfide oligomer, polyether based urethane acrylate oligomer, polyester based urethane acrylate oligomer, iso-octyl acrylate, N-iso-butoxymethyl methacrylomide, N-vinyl caprolactam, hexandiol diacrylate, or combinations thereof.

8. The method of claim 1 further comprising adding a crosslinking agent to the crosslinkable oligomeric resin composition.

9. The method of claim 8 wherein the crosslinking is initiated by ultraviolet radiation.

10. The method of claim 1 further comprising adding a photoinitiator to the crosslinkable oligomeric resin composition.

11. A method of forming a microstructure bearing article that exhibits increased resistance to scratching, the article having alternating polymeric grooves and tips formed from a crosslinkable oligomeric resin composition on a substrate, the method comprising:

depositing the crosslinkable oligomeric resin composition onto a master negative microstructured surface in an amount barely sufficient to fill cavities of the master;

filling the cavities by moving a bead of the oligomeric resin composition between the substrate and the master, at least one of which is flexible, the oligomeric resin composition forming the alternating tips and grooves; and

curing the oligomeric resin composition that forms the tips and grooves to an extent that the microstructure bearing article exhibits a haze increase of less than or equal to 60 percent after abrading the microstructure according to ASTM D-968-81 procedure using 200 milliliters of sand.

12. The method of claim 11 wherein the crosslinkable oligomeric resin composition forms a polymer having a tensile modulus of less than 6.8×

10⁸ pascals when evaluated according to ASTM D-882-91 procedure.

13. The method of claim 11 wherein the oligomeric composition forms a polymer which exhibits an elongation at break of greater than 50 percent when evaluated according to ASTM D-882-91 procedure.

14. The method of claim 11 wherein the crosslinkable oligomeric resin composition comprises at least one resin selected from the group consisting of acrylate or thioacrylate terminated polythioether oligomer, acrylated liquid polysulfide oligomer, polyether based urethane acrylate oligomer, polyester based urethane acrylate oligomer, iso-octyl acrylate, N-iso butoxymethyl methacrylamide, N-vinyl caprolactam, hexandiol diacrylate, or combinations thereof.

15. The method of claim 11 further comprising adding a crosslinking agent to the crosslinkable oligomeric resin composition.

16. The method of claim 11 further comprising adding a photoinitiator to the crosslinkable oligomeric resin composition.

17. The method of claim 16 wherein the crosslinking is initiated by ultraviolet radiation.

18. The method of claim 11 wherein the tips have an included angle in the approximate range of 70°

to 120°

.