Dual-cure nanostructure transfer film

• US 10,106,643 B2
• Filed: 03/31/2015
• Issued: 10/23/2018
• Est. Priority Date: 03/31/2015
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Schwartz, Evan L., Hartmann-Thompson, Claire, Cheng, Shijing, Erickson, Nicholas C.
• Primary Examiner(s): Yang, Z. Jim
• Application Number:
  US14/674,819
• Publication Number:
  US 20160288450A1
• Time in Patent Office: 1,302 Days
• Field of Search: 428161-165
• CPC Class Codes: B32B 2255/10 on synthetic resin layer or on natural or synthetic rubber layer
• CPC Class Codes: B32B 2255/20 Inorganic coating
• CPC Class Codes: B32B 2255/26 Polymeric coating
• CPC Class Codes: B32B 2307/412 Transparent
• CPC Class Codes: B32B 2307/538 Roughness
• CPC Class Codes: B32B 2405/00 Adhesive articles, e.g. adhesive tapes labels B32B2519/00
• CPC Class Codes: B32B 2451/00 Decorative or ornamental articles wall paper B32B2607/02
• CPC Class Codes: B32B 2457/12 Photovoltaic modules
• CPC Class Codes: B32B 2457/206 Organic displays, e.g. OLED
• CPC Class Codes: B32B 2551/00 Optical elements
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/26 using curing agents
• CPC Class Codes: B32B 27/308 comprising acrylic (co)polymers
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 27/38 comprising epoxy resins
• CPC Class Codes: B32B 3/28 characterised by a layer comprising a deformed thin sheet , i.e. the layer having its entire thickness deformed out of the plane, e.g. corrugated, crumpled B32B29/08 takes precedence
• CPC Class Codes: B32B 3/30 characterised by a layer formed with recesses or projections, e.g. hollows, grooves, protuberances, ribs apertured layer B32B3/266; layer with cavities or internal voids B32B3/26
• CPC Class Codes: B32B 7/06 permitting easy separation
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: C08G 59/14 Polycondensates modified by chemical after-treatment
• CPC Class Codes: C08G 59/1466 : Acrylic or methacrylic acids
• CPC Class Codes: C08J 3/243 : Two or more independent types of crosslinking for one or more polymers
• CPC Class Codes: C08J 3/244 : Stepwise homogeneous crosslinking of one polymer with one crosslinking system, e.g. partial curing
• CPC Class Codes: H10K 71/00 : Manufacture or treatment specially adapted for the organic devices covered by this subclass
• CPC Class Codes: H10K 71/40 : Thermal treatment, e.g. annealing in the presence of a solvent vapour

Abstract

A transfer film includes a template layer having a first major surface and an opposing second major surface. The second major surface includes a structured non-planar release surface. A backfill layer is disposed upon and conforms to the non-planar structured surface. The backfill layer includes a first cross-linked polymer and a plurality of multifunctional monomers, which cure via different and independent curing mechanisms.

Claims

1. A transfer film comprising:

a template layer having a first major surface and an opposing second major surface, the second major surface comprising a structured non-planar release surface; and

a backfill layer disposed upon and conforming to the non-planar structured surface, the backfill layer comprising a thermal cationically cured layer prepared as follows;

preparing a mixture comprising;

about 0.1 to about 20 wt-% of an epoxy curable by a first curing mechanism comprising thermal cationic curing;

about 60 to about 90 wt-% of multifunctional acrylate monomers curable with a second curing mechanism different from the first curing mechanism, the multifunctional acrylate monomers selected from the group consisting of ethylene glycol diacrylate, ethylene glycol dimethacrylate, hexanediol diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, glycerol triacrylate, pentaerthyitol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, neopentylglycol diacrylate, cycloaliphatic multifunctional (meth)acrylates, and combinations thereof; and

about 5 to about 40 wt-% of a compatibilizer comprising molecules with acrylate functional groups and epoxy functional groups;

curing the mixture by thermal cationic curing,

wherein at least some of the epoxy functional groups of the epoxy and at least some of the epoxy functional groups of the compatibilizer are cured by thermal cationic curing to form a network of cross-linked epoxy having dispersed therein the multifunctional acrylate monomers, thereby forming the thermal cationically cured layer; and

wherein the backfill layer forms a pressure sensitive adhesive at room temperature.

2. The transfer film according to claim 1, wherein the backfill layer includes a free radical photoinitiator to cure the multifunctional acrylate monomers via a photo free radical mechanism.

3. The transfer film according to claim 1, wherein the backfill layer has a glass transition temperature value that is less than 25 degrees centigrade.

4. The transfer film according to claim 1, wherein the epoxy comprises cycloaliphatic multifunctional epoxy monomers.

5. The transfer film according to claim 1, wherein the multifunctional acrylate monomers are curable via a free-radical mechanism.

6. The transfer film according to claim 1, further comprising a release liner disposed on a planar major surface of the back fill layer wherein the backfill layer is between the release liner and the structured non-planar release surface.

7. The transfer film according to claim 1, wherein the backfill layer has an elastic modulus of less than 0.3×

10⁵ Pa.

8. An article comprising:

the transfer film according to claim 1 disposed on a receptor substrate.

9. The article according to claim 8, wherein the receptor substrate comprises glass or sapphire.

10. The article according to claim 8, wherein the receptor substrate comprises an organic light emitting diode color filter element.

11. An article comprising:

a receptor substrate having a receptor surface;

a light transmission layer having a first major surface adhered to the receptor surface and an opposing second major surface having a structured non-planar surface, the light transmission layer comprising an interpenetrating network prepared as follows;

preparing a mixture comprising;

about 0.1 to about 20 wt-% of an epoxy curable by a first curing mechanism comprising thermal cationic curing;

about 60 to about 90 wt-% of multifunctional acrylate monomers curable with a second curing mechanism different from the first curing mechanism, the multifunctional acrylate monomers selected from the group consisting of ethylene glycol diacrylate, ethylene glycol dimethacrylate, hexanediol diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, glycerol triacrylate, pentaerthyitol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, neopentylglycol diacrylate, cycloaliphatic multifunctional (meth)acrylates, and combinations thereof; and

about 5 to about 40 wt-% of a compatibilizer comprising molecules with acrylate functional groups and epoxy functional groups;

curing the mixture by thermal cationic curing;

wherein at least some of the epoxy functional groups of the epoxy and at least some of the epoxy functional groups of the compatibilizer are cured by thermal cationic curing to form a network of cross-linked epoxy having dispersed therein the multifunctional acrylate monomers, thereby forming a partially cured layer; and

curing the partially cured layer by free radical curing;

wherein at least some of the acrylate functional groups of the multifuctional acrylate monomers and at least some of the acrylate functional groups of the compatibilizer are cured by the free radical curing to form a cross-linked acrylate, and

wherein the cross-linked epoxy produced by the thermal cationic curing and the cross-linked acrylate produced by the free radical curing form the interpenetrating network of the light transmission layer; and

wherein the light transmission layer has a haze value of less than 2% and a visible light transmission greater than 85% and a decomposition temperature greater than 250 degrees centigrade.

12. The article according to claim 11, wherein the epoxy polymer comprises multifunctional cycloaliphatic epoxy monomers.

13. The article according to claim 11, wherein the receptor substrate comprises an organic light emitting diode color filter element.

14. A transfer film comprising:

a template layer having a first major surface and an opposing second major surface, the second major surface comprising a structured non-planar release surface; and

a backfill layer disposed upon and conforming to the non-planar structured surface, the backfill layer comprising a thermal cationically cured layer prepared as follows;

preparing a mixture comprising;

about 0.1 to about 15 wt-% of an epoxy curable by a first curing mechanism comprising thermal cationic curing;

about 60 to about 90 wt-% of multifunctional acrylate monomers curable with a second curing mechanism different from the first curing mechanism; and

about 5 to about 40 wt-% of a compatibilizer comprising molecules with acrylate functional groups and epoxy functional groups;

curing the mixture by thermal cationic curing,

wherein at least some of the epoxy functional groups of the epoxy and at least some of the epoxy functional groups of the compatibilizer are cured by thermal cationic curing to form a network of cross-linked epoxy having dispersed therein the multifunctional acrylate monomers, thereby forming the thermal cationically cured layer; and

wherein the backfill layer forms a pressure sensitive adhesive at room temperature.

15. A transfer film comprising:

a template layer having a first major surface and an opposing second major surface, the second major surface comprising a structured non-planar release surface; and

a backfill layer disposed upon and conforming to the non-planar structured surface, the backfill layer comprising a thermal cationically cured layer prepared as follows;

preparing a mixture comprising;

about 0.1 to about 20 wt-% of an epoxy curable by a first curing mechanism comprising thermal cationic curing;

about 70 to about 90 wt-% of multifunctional acrylate monomers curable with a second curing mechanism different from the first curing mechanism; and

about 5 to about 40 wt-% of a compatibilizer comprising molecules with acrylate functional groups and epoxy functional groups;

curing the mixture by thermal cationic curing,

wherein at least some of the epoxy functional groups of the epoxy and at least some of the epoxy functional groups of the compatibilizer are cured by thermal cationic curing to form a network of cross-linked epoxy having dispersed therein the multifunctional acrylate monomers, thereby forming the thermal canonically cured layer; and

wherein the backfill layer forms a pressure sensitive adhesive at room temperature.