Window cover film and flexible display panel including the same

Patent metadata

Field	Value
Publication number	US-12180382-B2
Application number	US-202117229095-A
Country	US
Kind code	B2
Filing date	Apr 13, 2021
Priority date	Apr 14, 2020
Publication date	Dec 31, 2024
Grant date	Dec 31, 2024

Abstract

Provided is a window cover film and a flexible display panel including the same. More particularly, a window cover film including a substrate layer and a hard coating layer and a flexible display panel including the same are provided.

First claim

What is claimed is:

1. A window cover film comprising a substrate layer made up of a polyamideimide-based resin and a hard coating layer formed directly on at least one surface of the substrate layer,
wherein a kinetic friction coefficient is less than 0.15, the kinetic friction coefficient being measured at a speed of 100 mm/min with a force of 5 N under a load of 200 g using parchment paper as an object to be frictionized on the hard coating layer, and a ratio of a static friction coefficient a to the kinetic friction coefficient b satisfies the following Equation 1:
1≤ a/b≤ 1.2,  [Equation 1]

wherein the substrate layer is made up of a polyamideimide (PAI)-based resin including a fluorine atom and an aliphatic cyclic structure and the hard coating layer is formed of a composition for forming a hard coating layer including a (meth) acryl-based siloxane resin and a polyfunctional (meth) acrylate-based compound, and
wherein the polyamideimide (PAI)-based resin is prepared by preparing an amine-terminated polyamide oligomer from a first fluorine-based aromatic diamine and an aromatic diacid dichloride, and polymerizing the amine-terminated polyamide oligomer with a monomer derived from a second fluorine-based aromatic diamine, an aromatic dianhydride, and a cycloaliphatic dianhydride.

2. The window cover film of claim 1 , wherein the static friction coefficient is 0.2 or less.

3. The window cover film of claim 1 , wherein the kinetic friction coefficient is 0.1 or less.

4. The window cover film of claim 1 , wherein the substrate layer has a modulus in accordance with ASTM D882 of 3 GPa or more, an elongation at break of 8% or more, a light transmittance of 5% or more as measured at 388 nm in accordance with ASTM D1746, a total light transmittance of 87% or more as measured at 400 to 700 nm, a haze of 2.0% or less, a yellow index of 5.0 or less, and a b* value of 2.0 or less.

5. The window cover film of claim 1 , wherein the substrate layer has a thickness of 10 to 500 μm and the hard coating layer has a thickness of 1 to 50 μm.

6. The window cover film of claim 1 , wherein the hard coating layer has a pencil hardness of 4H or more and a water contact angle of 80° or more.

7. The window cover film of claim 1 , wherein the window cover film has a curl amount of 5 mm or less, the curl amount being measured at each vertex of a square sample having a side length of 10 cm each which has been cut to be inclined at an angle of 45° to an MD direction of the film.

8. The window cover film of claim 1 , wherein the window cover film has no crack occurrence at 30,000 to 200,000 times in evaluation of dynamic bending properties.

9. A flexible display panel comprising the window cover film of claim 1 .

Assignees

• Sk Innovation Co Ltd
• Sk Ie Tech Co Ltd

Inventors

• Ahn Jong Nam

Classifications

• H05K5/03

  Covers · CPC title

• C09D183/04

  Polysiloxanes · CPC title

• C08G73/14 Primary

  Polyamide-imides · CPC title

• C08J2351/08

  grafted on to macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C08J2379/08

  Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors · CPC title