Process and apparatus for a nanovoided article

• US 9,464,179 B2
• Filed: 07/07/2014
• Issued: 10/11/2016
• Est. Priority Date: 04/15/2009
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Kolb, William B., Hao, Encai, Kolb, Brant U., Phillips, David L.
• Primary Examiner(s): LIGHTFOOT, ELENA TSOY
• Application Number:
  US14/324,313
• Publication Number:
  US 20140323603A1
• Time in Patent Office: 827 Days
• US Class Current: 1/1
• CPC Class Codes: C08J 2201/0502 the liquid phase being organic
• CPC Class Codes: C08J 2205/042 Nanopores, i.e. the average diameter being smaller than 0,1 micrometer
• CPC Class Codes: C08J 9/0004 Use of compounding ingredients, the chemical constitution of which is unknown, broadly defined, or irrelevant
• CPC Class Codes: C08J 9/286 the liquid phase being a solvent for the monomers but not for the resulting macromolecular composition, i.e. macroporous or macroreticular polymers

Abstract

A process and apparatus for producing a nanovoided article, a nanovoided coating, and a low refractive index coating is described. The process includes providing a first solution of a polymerizable material in a solvent; at least partially polymerizing the polymerizable material to form a composition that includes an insoluble polymer matrix and a second solution, wherein the insoluble polymer matrix includes a plurality of nanovoids that are filled with the second solution; and removing a major portion of the solvent from the second solution. An apparatus for the process is also described, and includes a webline, a coating section, a partial polymerization section, and a solvent removal section.

Claims

1. A process for producing a nanovoided article, comprising:

providing a first solution comprising a polymerizable material in a solvent, wherein the first solution further comprises nanoparticles, and wherein a weight ratio of polymerizable material to the nanoparticles in the first solution is greater than about 30;

70;

at least partially polymerizing the polymerizable material with ultraviolet (UV) radiation produced by at least one light emitting diode (LED) to form a composition comprising an insoluble polymer matrix substantially bicontinuous with a second solution, wherein the insoluble polymer matrix comprises a plurality of nanovoids that are filled with the second solution, and wherein at least some of the nanoparticles are bound to the insoluble polymer matrix during the polymerizing step; and

removing a major portion of the solvent from the second solution.

2. The process of claim 1, wherein the polymerizable material comprises a crosslinkable material, and at least partially polymerizing comprises crosslinking the crosslinkable material.

3. The process of claim 1, wherein the solvent comprises an organic solvent.

4. The process of claim 1, wherein the solvent comprises a blend of at least two organic solvents.

5. The process of claim 1, wherein removing a major portion of the solvent comprises drying in a thermal oven, drying with infrared light sources, vacuum drying, gap drying, or a combination thereof.

6. The process of claim 1, wherein a weight percent solids of the first solution is greater than about 5% and less than about 90%.

7. The process of claim 1, wherein a weight percent solids of the first solution is greater than about 10% and less than about 60%.

8. The process of claim 1, wherein a weight percent solids of the first solution is greater than about 30% and less than about 40%.

9. The process of claim 1, wherein the nanoparticles comprise surface modified nanoparticles.

10. The process of claim 9, wherein the surface modified nanoparticles comprise reactive nanoparticles, non-reactive nanoparticles, or combinations thereof.

11. The process of claim 10, wherein a substantial portion of the reactive nanoparticles form a chemical bond with the insoluble polymer matrix.

12. The process of claim 10, wherein a substantial portion of the non-reactive nanoparticles form a physical bond with the insoluble polymer matrix.

13. The process of claim 1, wherein a weight ratio of the polymerizable material to the nanoparticles ranges greater than 30:

70 to about 90;

10.

14. The process of claim 1, wherein the first solution further comprises a photoinitiator.

15. The process of claim 1, wherein the at least one LED comprises a peak wavelength at 365, 385, 395 or 405 nanometers.