Pressure-sensitive adhesive composition for foldable display

Patent metadata

Field	Value
Publication number	US-10920112-B2
Application number	US-201716331743-A
Country	US
Kind code	B2
Filing date	Sep 8, 2017
Priority date	Sep 9, 2016
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

The pressure-sensitive adhesive composition of the present application has excellent bending reliability while having appropriate adhesive force and cohesive force, thereby being useful for forming a pressure-sensitive adhesive layer for a foldable display having improved release force.

First claim

The invention claimed is:

1. A pressure-sensitive adhesive composition for a foldable display comprising:
a first pressure-sensitive adhesive comprising a first silicone gum and a first MQ resin, and having a peel force on a glass substrate, as measured at a peel rate of 0.3 m/min and a peel angle of 180 degrees, of 10 gf/in or less; and
a second pressure-sensitive adhesive comprising a second silicone gum and a second MQ resin, and having a peel force on a glass substrate, as measured at a peel rate of 0.3 m/min and a peel angle of 180 degrees, of 200 gf/in to 400 gf/in,
wherein said first pressure-sensitive adhesive is contained in an amount of 5 wt % to 50 wt % relative to the total solid content of the composition,
wherein MQ resin is a silicone compound having at least a three-dimensional reticular steric molecular structure comprising a monofunctional siloxane unit (M Unit) and a tetrafunctional siloxane unit (Q unit), and
the composition satisfies Equation 1 below:
A< 20 gf/in  [Equation 1]

wherein, A means a peel force of a pressure-sensitive adhesive layer formed by curing the pressure-sensitive adhesive composition on a fluorine-based release film, as measured at a peel rate of 0.3 m/min and a peel angle of 180 degrees.

2. The pressure-sensitive adhesive composition for a foldable display according to claim 1 ,
wherein the first or second silicone gum is represented by Formula 1 below:

wherein, R 1 and R 6 are each independently a silyl group or silanol group with or without an alkyl group, an alkenyl group or an aryl group, R 2 to R 5 are each independently an alkyl group, an alkenyl group or an aryl group, and n and m are each independently an integer in a range of 1 to 10,000.

3. The pressure-sensitive adhesive composition for a foldable display according to claim 1 ,
wherein the first pressure-sensitive adhesive comprises the first MQ resin in a content of less than 5 wt %.

4. The pressure-sensitive adhesive composition for a foldable display according to claim 1 ,
wherein the first silicone gum has a number average molecular weight in a range of 400,000 to 800,000.

5. The pressure-sensitive adhesive composition for a foldable display according to claim 1 ,
wherein the first silicone gum has a vinyl group content in a range of 0.5 to 1.5 mol %.

6. The pressure-sensitive adhesive composition for a foldable display according to claim 1 ,
wherein the second pressure-sensitive adhesive has a storage elastic modulus measured at −40° C. of 10 Pa or less.

7. The pressure-sensitive adhesive composition for a foldable display according to claim 1 ,
wherein the second pressure-sensitive adhesive comprises the second MQ resin in a content of 40 wt % or less.

8. The pressure-sensitive adhesive composition for a foldable display according to claim 1 ,
wherein the second silicone gum is a linear polydimethylsiloxane containing hydroxy groups at both ends.

9. The pressure-sensitive adhesive composition for a foldable display according to claim 1 ,
wherein a storage elastic modulus (G′) after curing is 5×10 6 Pa or less within a temperature range of −40° C. to 90° C.

10. A foldable display comprising a pressure-sensitive adhesive layer which is a cured product of the pressure-sensitive adhesive composition for a foldable display of claim 1 attached to an adherend.

11. The foldable display according to claim 10 ,
wherein the adherend is a base film, and said base film and said pressure-sensitive adhesive layer form covalent bonds via silanol groups contained in said pressure-sensitive adhesive layer.

12. The foldable display according to claim 10 ,
wherein the pressure-sensitive adhesive layer has a peel force on the adherend as measured at a peel rate of 0.3 m/min and a peel angle of 180 degrees of 2,000 gf/in or more.

Assignees

• Lg Chemical Ltd

Inventors

• Park Hyon Gyu
• Roh Dong Kyu
• Kwon Yoon Kyung

Classifications

• C09J7/00

  Adhesives in the form of films or foils · CPC title

• C09J183/04 Primary

  Polysiloxanes · CPC title

• C09J7/255

  Polyesters · CPC title

• C08G77/20

  containing silicon bound to unsaturated aliphatic groups · CPC title

• C08G77/16

  to hydroxy groups · CPC title