Adhesive film, electronic device including the same, and vehicle including the electronic device

Patent metadata

Field	Value
Publication number	US-2024318046-A1
Application number	US-202418614565-A
Country	US
Kind code	A1
Filing date	Mar 22, 2024
Priority date	Mar 24, 2023
Publication date	Sep 26, 2024
Grant date	—

Abstract

An adhesive film formed by curing a composition including a high-molecular-weight acrylic polymer having a weight average molecular weight of 700,000 or more, a low-molecular-weight acrylic polymer having a weight average molecular weight of less than 500,000, and a cross-linking agent, a photoinitiator, a molecular weight regulator, or a combination thereof is provided. Based on 100 parts by weight, which is a sum of an amount of the high-molecular-weight acrylic polymer and an amount of the low-molecular-weight acrylic polymer, the amount of the high-molecular-weight acrylic polymer is 30 parts by weight or more, and the adhesive film has a degree of stress relaxation of 0.01 to 0.50 , a creep at 50° C. of 4% or more, and a modulus at 25° C. of 0.04 MPa to 0.70 MPa.

First claim

What is claimed is:

1 . An adhesive film,
wherein the adhesive film is formed by first-curing a composition, wherein the composition comprises:
a high-molecular-weight acrylic polymer having a first weight average molecular weight of 700,000 or more;
a low-molecular-weight acrylic polymer having a second weight average molecular weight of at most 500,000; and
a cross-linking agent, a photoinitiator, a molecular weight regulator, or a combination thereof,
and
wherein, based on 100 parts by weight, which is a sum of an amount of the high-molecular-weight acrylic polymer and an amount of the low-molecular-weight acrylic polymer, the amount of the high-molecular-weight acrylic polymer is 30 parts by weight or more.

2 . The adhesive film of claim 1 , wherein
the adhesive film has a degree of stress relaxation calculated according to Equation 1 of about 0.01 to about 0.50, a creep at 50° C. of 4% or more, and a modulus at 25° C. of about 0.04 megapascal (MPa) to about 0.70 MPa:

SR
=

ST

3
⁢
0
⁢
0

/

ST
0.01

,

Equation
⁢

1

and
wherein, in Equation 1,
SR is the degree of stress relaxation,
ST 300 is a value of stress when a strain of 25% is applied for 300 seconds, and
ST 0.01 is a value of stress when a strain of 25% is applied for 0.01 seconds.

3 . The adhesive film of claim 1 , wherein
the first weight average molecular weight is about 700,000 to about 3,000,000.

4 . The adhesive film of claim 1 , wherein
the second weight average molecular weight is about 100,000 to about 300,000.

5 . The adhesive film of claim 1 , wherein
an adhesive strength of the adhesive film is 300 gram force per 28 millimeter (gf/28 mm) or more.

6 . The adhesive film of claim 1 , wherein
a degree of stress relaxation of the adhesive film after second-curing the adhesive film is about 0.20 to about 0.70.

7 . The adhesive film of claim 1 , wherein
the high-molecular-weight acrylic polymer is a polymer of a first compound represented by Formula 1 and a second compound represented by Formula 2, the low-molecular-weight acrylic polymer is a polymer of the first compound represented by Formula 1 and the second compound represented by Formula 2, the first compound and the second compound are different from each other:

wherein, in Formulae 1 and 2,
R 1 to R 4 are each independently hydrogen, deuterium, a hydroxyl group, or a C 1 -C 10 alkyl group, and
n is an integer from 1 to 10.

8 . The adhesive film of claim 1 , wherein
the cross-linking agent is represented by Formula 3:

wherein, in Formula 3,
X and Y are each independently CH 2 or O,
R 5 and R 6 are each independently hydrogen, deuterium, a hydroxyl group, or a C 1 -C 10 alkyl group, and
m is an integer from 1 to 10.

9 . The adhesive film of claim 2 , wherein
each of ST 300 and ST 0.01 is measured at 70° C.

10 . The adhesive film of claim 1 , wherein
the adhesive film further comprises the cross-linking agent, the photoinitiator, and the molecular weight regulator, wherein, based on 100 parts by weight, which is the sum of the amount of the high-molecular-weight acrylic polymer and the amount of the low-molecular-weight acrylic polymer, an amount of the cross-linking agent is about 0.01 parts by weight to about 0.5 parts by weight, an amount of the photoinitiator is 0.01 parts by weight to 0.4 parts by weight, and an amount of the molecular weight regulator is 0.01 parts by weight to 0.2 parts by weight.

11 . The adhesive film of claim 1 , wherein
the adhesive film is an optical clear adhesive (OCA).

12 . An adhesive film,
wherein the adhesive film is formed by curing a composition, and wherein the composition comprises:
an acrylic polymer; and
a cross-linking agent, a photoinitiator, a molecular weight regulator, or a combination thereof,
wherein the adhesive film has
a degree of stress relaxation calculated according to Equation 1 of about 0.20 to about 0.70,
a creep at 50° C. of 4% or more, and
a modulus at 25° C. of about 0.04 MPa to about 0.70 MPa:

SR
=

ST

3
⁢
0
⁢
0

/

ST
0.01

,

Equation
⁢

1

and
wherein, in Equation 1,
SR is the degree of stress relaxation,
ST 300 is a value of stress when a strain of 25% is applied for 300 seconds, and
ST 0.01 is a value of stress when a strain of 25% is applied for 0.01 seconds.

13 . The adhesive film of claim 12 , wherein
a weight average molecular weight of the acrylic polymer is about 100,000 to about 3,000,000.

14 . The adhesive film of claim 12 , wherein
an adhesive strength of the adhesive film is 300 gf/28 mm or more.

15 . The adhesive film of claim 12 , wherein
the adhesive film is ultraviolet (UV) cured using a light amount of about 500 millijoule (mJ) to about 1500 mJ.

16 . The adhesive film of claim 12 , wherein
the acrylic polymer is a polymer of a first compound represented by Formula 1 and a second compound represented by Formula 2, and the first compound and the second compound are different from each other:

wherein, in Formulae 1 and 2,
R 1 to R 4 are each independently hydrogen, deuterium, a hydroxyl group, or a C 1 -C 10 alkyl group, and
n is an integer from 1 to 10.

17 . The adhesive film of claim 16 , wherein,
based on 100 parts by

Assignees

• Samsung Display Co Ltd

Inventors

• Lee Joosub
• Park Youngju
• Yoo Seongsoo
• Eun Sangwon
• Lee Jinyoung

Classifications

• C09J133/066

  containing -OH groups · CPC title

• C08F220/20

  of polyhydric alcohols or phenols {, e.g. 2-hydroxyethyl (meth)acrylate or glycerol mono-(meth)acrylate} · CPC title

• C08F220/1808

  C8-(meth)acrylate, e.g. isooctyl (meth)acrylate or 2-ethylhexyl (meth)acrylate · CPC title

• H05K5/03

  Covers · CPC title

• C09J2433/00

  Presence of (meth)acrylic polymer · CPC title