Light management films with zirconia particles

• US 20060204745A1
• Filed: 03/14/2005
• Published: 09/14/2006
• Est. Priority Date: 03/14/2005
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Goenner, Emily S., Kolb, Brant U., Olson, David B., Lamansky, Sergey S., Cowher, John T., Jones, Clint L.
• Application Number:
  US11/079,832
• Publication Number:
  US 20060204745A1
• Time in Patent Office: Days
• US Class Current: 428/328
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/256 Heavy metal or aluminum or compound thereof

Abstract

Light management films and methods of making light management films are described. The light management films contain an optical layer that contains polymeric material and zirconia particles. The zirconia particles are colloidal, crystalline, substantially non-associated, and have a narrow size distribution.

Claims

1. A light management film comprising an optical layer having a microstructured surface, the optical layer comprising

(a) a polymeric material;

and

(b) a plurality of surface-modified zirconia particles, wherein the zirconia particles comprise 0.1 to 8 weight percent yttrium based on a weight of inorganic oxides in the zirconia particles and wherein the zirconia particles have an average primary particle size no greater than 30 nanometers, a dispersion index of 1 to 3, a ratio of intensity-average particle size to volume-average particle size no greater than 3.0, and a crystal structure that is at least 70 percent cubic, tetragonal, or a combination thereof.

2. The light management film of claim 1, wherein the light management film is selected form a brightness enhancement film, a reflective film, or a turning film.

3. The light management film of claim 1, wherein the light management film is a brightness enhancement film.

4. The light management film of claim 1, further comprising a base layer adjacent to the optical layer.

5. The light management film of claim 1, wherein the optical layer comprises up to 80 weight percent zirconia particles based on the weight of the optical layer.

6. The light management film of claim 1, wherein the polymeric material is a reaction product of a polymerizable composition comprising an oligomeric material having a high refractive index, a reactive diluent, and a multi-functional cross-linking monomer.

7. The light management film of claim 1, wherein the polymeric material is a reaction product of a polymerizable composition comprising a cross-linking agent and a monomer of Formula I

wherein

R^a is hydrogen or methyl;

Q is oxy or thio;

R^c is a C₂ to C₁₂ alkylene that is unsubstituted or substituted with a hydroxy;

n is an integer of 0 to 6;

m is an integer of 0 to 6;

each X is independently hydrogen, bromo, or chloro; and

Y is a divalent linking group selected from −

C(CH₃)₂—

, —

CH₂—

, —

S—

, —

S(O)—

, or —

S(O)₂—

.

8. The light management film of claim 7, the polymerizable composition further comprising a monomer of Formula II

wherein

Ar is a phenyl or naphthyl that is unsubstituted or substituted with one or more substituents selected from halo, alkyl, aryl, aralkyl, or combination thereof;

Q is oxy or thio;

R^c is a C₂ to C₁₂ alkylene that is unsubstituted or substituted with a hydroxy;

p is an integer of 0 to 6; and

R^a is hydrogen or methyl.

9. The light management film of claim 1, wherein the polymerizable composition further comprises a monomer of Formula II

wherein

Ar is a phenyl or naphthyl that is unsubstituted or substituted with one or more substituents selected from halo, alkyl, aryl, aralkyl, or combination thereof;

Q is oxy or thio;

R^c is a C₂ to C₁₂ alkylene that is unsubstituted or substituted with a hydroxy;

p is an integer of 0 to 6; and

R^a is hydrogen or methyl.

10. The light management film of claim 1, wherein the polymeric material is the reaction product of a polymerizable composition comprising a brominated, alkyl-substituted phenyl (meth)acrylate.

11. The light management film of claim 1, wherein the polymerizable composition comprises a monomer of Formula III, a monomer of Formula IV, or a combination thereof

wherein

each R¹ is independently selected from a formula of

R³ is (CH₂)_x;

x is an integer of 2 to 8; and

R⁴ is hydrogen or methyl.

12. The light management film of claim 1, wherein the polymerizable composition comprises a monomer of Formula V

wherein

R² is hydrogen or methyl;

Ar is an aryl;

m is an integer of 1 to 6;

n is an integer of 1 to 6;

p is an integer of 1 to 6; and

q is an integer of 1 to 6.

13. The light management film of claim 1, wherein the polymeric material is a thermoplastic material.

14. The light management film of claim 1, wherein the zirconia particles are surface-modified with a carboxylic acid.

15. The light management film of claim 14, wherein the zirconia particles are surface treated with a first carboxylic acid that is free of a polymerizable group and a second carboxylic acid that contains a polymerizable group.

16. The light management film of claim 1, wherein the zirconia particles are surface-modified with a silane.

17. A method of preparing a light management film, the method comprising

providing a zirconia sol comprising zirconia particles dispersed in an aqueous phase, the zirconia sol being prepared by a method comprising

preparing a first feedstock that contains a zirconium salt, subjecting the first feedstock to a first hydrothermal treatment to form a zirconium-containing intermediate and a byproduct;

forming a second feedstock by removing at least a portion of the byproduct of the first hydrothermal treatment; and

subjecting the second feedstock to a second hydrothermal treatment;

modifying the surface of the zirconia particles to form surface-modified zirconia particles;

preparing a coating composition comprising the surface-modified zirconia particles and an organic matrix;

contacting the coating composition with a micro-replication tool; and

polymerizing the coating composition to form an optical layer having a microstructured surface.

18. The method of claim 17, wherein the light management film is brightness enhancement film.

19. A method of preparing a light management film, the method comprising

providing a zirconia sol comprising zirconia particles dispersed in an aqueous phase, the zirconia sol further comprising a carboxylic acid that contains no greater than four carbon atoms and that is substantially free of a polyether carboxylic acid, wherein the zirconia particles have an average primary particle size no greater than 50 nanometers, a dispersion index of 1 to 5, a ratio of intensity-average particle size to volume-average particle size no greater than 3.0, and a crystal structure that is at least 50 percent cubic, tetragonal, or a combination thereof;

modifying the surface of the zirconia particles to form surface-modified zirconia particles;

preparing a coating composition comprising the surface-modified zirconia particles and an organic matrix;

contacting the coating composition with a micro-replication tool; and

polymerizing the coating composition to form an optical layer having a microstructured surface.

20. The method of claim 19, wherein the zirconia particles contain 0.1 to 8 weight percent yttrium based on the weight of the inorganic oxides in the zirconia particles and have a crystal structure that is at least 70 percent cubic, tetragonal, or a combination thereof.

21. The method of claim 19, wherein the light management film is a brightness enhancement film.