# US 11,440,302 B2 · Thin protective display film

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- Number: US 11,440,302 B2
- Document ID: US11440302B2
- Status: Granted
- Kind: B2
- Application number: 15/986,912
- Filed: 2018-05-23
- Published: 2018-09-20
- Granted: 2022-09-13
- Earliest claimed: 2015-12-15
- Assignees: 3M Innovative Properties Company
- Applicants: 3M Innovative Properties Company
- Inventors: Catherine A. Leatherdale; David Scott Thompson; Michael A. Johnson; John J. Stradinger; Evan L Breedlove; Steven D. Solomonson; Joseph D. Rule; Peter D. Condo
- Web page: https://patentgrep.com/patent/US11440302B2

## CPC

- B32B 27/281: {comprising polyimides}
- B32B 7/06: permitting easy separation
- B32B 7/12: using interposed adhesives or interposed materials with bonding properties
- B32B 27/08: of synthetic resin
- B32B 27/16: specially treated, e.g. irradiated
- B32B 27/308: {comprising acrylic (co)polymers}
- B32B 27/325: {comprising polycycloolefins}
- B32B 27/34: comprising polyamides
- B32B 27/36: comprising polyesters
- B32B 27/365: {comprising polycarbonates}
- B32B 27/40: comprising polyurethanes
- C08J 7/042: {with two or more layers, where at least one layer of a composition contains a polymer binder}
- C08J 7/043: Improving the adhesiveness of the coatings per se, e.g. forming primers (adhesives in the form of films or foils characterised by the primer layers between the polymer carriers and the adhesives C09J7/50)
- C08J 7/046: Forming abrasion-resistant coatings; Forming surface-hardening coatings
- C08J 7/048: Forming gas barrier coatings
- H10K 77/111: {Flexible substrates}
- B32B 2250/03: 3 layers
- B32B 2250/24: All layers being polymeric
- B32B 2255/10: on synthetic resin layer or on natural or synthetic rubber layer
- B32B 2255/26: Polymeric coating
- B32B 2255/28: Multiple coating on one surface
- B32B 2307/40: having particular optical properties
- B32B 2307/412: Transparent
- B32B 2307/50: having particular mechanical properties
- B32B 2307/536: Hardness
- B32B 2307/54: Yield strength; Tensile strength
- B32B 2307/546: Flexural strength; Flexion stiffness
- B32B 2307/584: Scratch resistance
- B32B 2307/72: Density
- B32B 2307/7244: Oxygen barrier
- B32B 2307/7265: Non-permeable
- B32B 2307/732: Dimensional properties
- B32B 2307/734: Dimensional stability
- B32B 2307/748: Releasability
- B32B 2457/20: Displays, e.g. liquid crystal displays, plasma displays
- B32B 2457/202: LCD, i.e. liquid crystal displays
- B32B 2457/206: Organic displays, e.g. OLED
- C08J 2379/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C08J 2475/04: Polyurethanes
- Y02E 10/549: Organic PV cells
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A display film includes a transparent polymeric substrate layer having a 0.2% offset yield stress greater than 110 MPa and a transparent aliphatic cross-linked polyurethane layer having a thickness of 100 micrometers or less disposed on the transparent polymeric substrate layer. The transparent aliphatic cross-linked polyurethane layer has a glass transition temperature in a range from 11 to 27 degrees Celsius and a Tan Delta peak value in a range from 0.5 to 2.5. The display film has a haze value of 2% or less.

## Claims

### Claim 1

A display film comprising:
a transparent polymeric substrate layer having a 0.2% offset yield stress greater than 110 MPa;
a transparent aliphatic cross-linked polyurethane layer having a glass transition temperature in a range from 11 to 27 degrees Celsius, a cross-link density in a range from 0.34 to 0.65 mol/kg, and a thickness in a range of 10 μm to 100 μm, and comprising aliphatic cross-linked polyurethane prepared by step-growth polymerization of polyol with an isocyanate-functional material; and
a hardcoat layer disposed on the transparent polymeric substrate layer or between the transparent polymeric substrate layer and the transparent aliphatic cross-linked polyurethane layer,
wherein the display film is transparent in a wavelength range of 380 nm to 700 nm.

### Claim 2 (depends on 1)

The display film according to claim 1, wherein the display film has a thickness of less than 200 micrometers and the transparent polymeric substrate layer has a 0.2% offset yield stress greater than 130 MPa.

### Claim 3 (depends on 1)

The display film according to claim 1, wherein the transparent aliphatic cross-linked polyurethane layer has a Tan Delta peak value in a range from 0.5 to 2.5.

### Claim 4 (depends on 1)

The display film according to claim 1, wherein the transparent aliphatic cross-linked polyurethane layer has a glass transition temperature in a range from 17 to 22 degrees Celsius and a Tan Delta peak value in a range from 1 to 2.

### Claim 5 (depends on 1)

The display film according to claim 1, wherein the display film has a haze of 2% or less.

### Claim 6 (depends on 1)

The display film according to claim 1, wherein the hardcoat layer is disposed on a first side of the transparent polymeric substrate layer and the transparent aliphatic cross-linked polyurethane layer is disposed on a second side of the transparent polymeric substrate layer opposite of the first side.

### Claim 7 (depends on 1)

The display film according to claim 1, wherein the hardcoat layer is disposed between the transparent polymeric substrate layer and the transparent aliphatic cross-linked polyurethane layer.

### Claim 8 (depends on 1)

The display film according to claim 1, wherein the hardcoat layer comprises multi-functional acrylate resin.

### Claim 9 (depends on 1)

The display film according to claim 1, wherein the hardcoat layer comprises nanosilica particles.

### Claim 10 (depends on 1)

The display film according to claim 1, further comprising a removable liner disposed on the transparent polymeric substrate layer or the transparent aliphatic cross-linked polyurethane layer.

### Claim 11 (depends on 1)

The display film according to claim 1, further comprising an optical adhesive layer disposed on the transparent polymeric substrate layer and a removable liner disposed on the optical adhesive layer.

### Claim 12 (depends on 1)

The display film according to claim 1, wherein the transparent polymeric substrate comprises polyimide.

### Claim 13 (depends on 12)

The display film according to claim 12, wherein the display film has a yellow color value b* of 5 or less.

### Claim 14

An article comprising:
an optical display;
a transparent protective film disposed on the optical display, the protective film comprising:
a transparent polymeric substrate layer;
a transparent aliphatic cross-linked polyurethane layer disposed on the transparent polymeric substrate layer and having a glass transition temperature in a range from 11 to 27 degrees Celsius, a cross-link density in a range from 0.34 to 0.65 mol/kg, and a thickness in a range of 20 μm to 100 μm, and comprising aliphatic cross-linked polyurethane prepared by step-growth polymerization of polyol with an isocyanate-functional material; and
a hardcoat layer disposed on the transparent polymeric substrate layer or the transparent aliphatic cross-linked polyurethane layer; and
an optical adhesive layer fixing the protective film to the optical display,
wherein the optical display and the protective film are foldable so that the optical display faces itself and at least a portion of the protective film overlaps another portion of the protective film, and
wherein the protective film is transparent from wavelength 380 nm to 700 nm.

### Claim 15 (depends on 14)

The article according to claim 14, wherein the optical display comprises an OLED display panel, an LCD panel, or a reflective display.

### Claim 16 (depends on 14)

The article according to claim 14, wherein the transparent polymeric substrate layer has a 0.2% offset yield stress greater than 110 MPa.

### Claim 17 (depends on 14)

The article according to claim 14, wherein the transparent protective film has a haze of 2% or less.