Thermoformed abrasion-resistant multilayer optical film and method of making the same

Patent metadata

Field	Value
Publication number	US-12053945-B2
Application number	US-201917059843-A
Country	US
Kind code	B2
Filing date	May 30, 2019
Priority date	Jun 4, 2018
Publication date	Aug 6, 2024
Grant date	Aug 6, 2024

Abstract

A method of making a shaped abrasion-resistant multilayer optical film includes providing a curable composition comprising, based on the total weight of components a) to d) components: a) 87 to 96 weight percent of urethane (meth)acrylate compound having an average (meth)acrylate functionality of 2 to 4.8; b) 2 to 12.5 weight percent of (meth)acrylate monomer having a (meth)acrylate functionality of 1 to 2, wherein the (meth)acrylate monomer does not comprise a urethane (meth)acrylate compound; optionally c) 0.5 to 2 weight percent of silicone (meth)acrylate; and d) optional effective amount of photoinitiator. The curable composition is coated onto an MOF. Optionally, the curable composition to is at least partially dried. Next, the curable composition or the at least partially dried curable composition is at least partially cured to provide an abrasion-resistant multilayer optical film. Lastly, the abrasion-resistant multilayer optical film is thermoformed using a female mold having a mold surface. At least a portion of the mold surface has a radius of curvature of 58 to 76 mm and a maximum depth of 13 to 20 mm.

First claim

What is claimed is:

1. A method of making a shaped abrasion-resistant multilayer optical film, the method comprising steps:
i) providing a curable composition comprising components:
a) 87 to 96 weight percent of urethane (meth)acrylate compound having an average (meth)acrylate functionality of 2 to 4.8, based on the total weight of components a) to d);
b) 2 to 12.5 weight percent of (meth)acrylate monomer having a (meth)acrylate functionality of 1 to 2, based on the total weight of components a) to d), wherein the (meth)acrylate monomer does not comprise a urethane (meth)acrylate compound;
c) 0.5 to 2 weight percent of silicone (meth)acrylate, based on the total weight of components a) to d);
d) an effective amount of photoinitiator;
e) optional inorganic nanoparticles; and
f) optional solvent;

ii) coating the curable composition onto a major surface of a multilayer optical film;
iii) optionally at least partially drying the curable composition to provide an at least partially dried curable composition;
iv) at least partially curing the curable composition or the at least partially dried curable composition to provide an abrasion-resistant multilayer optical film; and
v) thermoforming the abrasion-resistant multilayer optical film using a female thermoforming mold having a mold surface, wherein at least a portion of the mold surface has a radius of curvature of 58 to 76 millimeters and a maximum depth of 13 to 20 mm, to provide the shaped abrasion-resistant multilayer optical film.

2. The method of claim 1 , wherein the at least a portion of the mold surface has a radius of curvature of 65 to 68 millimeters.

3. The method of claim 1 , wherein the at least a portion of the mold surface has a radius of curvature of 66 to 67 millimeters.

4. The method of claim 1 , wherein component e) is present in the curable composition.

5. The method of claim 1 , wherein the inorganic nanoparticles comprise α-alumina nanoparticles.

6. The method of claim 1 , wherein component b) comprises at least one of 1,6-hexanediol di(meth)acrylate or an alkoxylated tetrahydrofurfuryl (meth)acrylate.

7. The method of claim 1 , wherein the urethane (meth)acrylate compound includes at least one of an isocyanurate ring or a biuret group.

8. The method of claim 1 , wherein the multilayer optical film is a reflective polarizer film.

9. The method of claim 8 , wherein the reflective polarizer film comprises an optical stack, and wherein the major surface of the reflective polarizer film comprises a layer that is coextruded with the optical stack.

10. The method of claim 1 , wherein the multilayer optical film is opposite the mold surface during thermoforming.

11. The method of claim 1 , wherein the maximum depth is 15 to 20 mm.

12. The method of claim 1 , wherein the maximum depth is 18 to 19 mm.

13. The method of claim 1 , wherein the urethane (meth)acrylate compound includes a biuret group.

14. The method of claim 1 , wherein the multilayer optical film comprises alternating polymer layers having different refractive indices, wherein each alternating polymer layer has an optical thickness of less than 1 micron.

15. The method of claim 1 , wherein the multilayer optical film is at least 70 percent reflective to wavelengths in the range of 400 nm to 700 nm.

16. The method of claim 1 , wherein the multilayer optical film is at least 50 percent reflective to wavelengths in the range of 700 nm to 2500 nm.

Assignees

• 3M Innovative Properties Company

Inventors

• Coonce Benjamin R
• Pokorny Richard J
• Klun Thomas P
• Zhang Chunjie
• Ambur Gregg A
• Sonnek Benjamin G
• Richter Daniel J
• Wu Jung-Sheng

Classifications

• C08G18/6715

  Unsaturated monofunctional alcohols or amines · CPC title

• B29K2033/12

  Polymers of methacrylic acid esters, e.g. PMMA, i.e. polymethylmethacrylate · CPC title

• C09D175/16

  having terminal carbon-to-carbon unsaturated bonds · CPC title

• C09D175/14

  Polyurethanes having carbon-to-carbon unsaturated bonds · CPC title

• B29C51/10

  Forming by pressure difference, e.g. vacuum · CPC title