Curable and cured adhesive compositions

Patent metadata

Field	Value
Publication number	US-11608399-B2
Application number	US-202117248381-A
Country	US
Kind code	B2
Filing date	Jan 22, 2021
Priority date	Sep 30, 2015
Publication date	Mar 21, 2023
Grant date	Mar 21, 2023

Abstract

Curable adhesive compositions are provided that can be cured using ultraviolet or visible light radiation. These curable adhesive compositions, which contain a curable (meth)acrylate copolymer, have a creep compliance that is less than 5(10 −4 ) inverse Pascals at 25° C., a creep compliance that is greater than 1(10 −3 ) inverse Pascals at 70° C., and a shear storage modulus greater than 40 kiloPascals when measured at 25° C. at a frequency of 1 radian/second.

First claim

We claim:

1. A curable adhesive composition comprising a curable (meth)acrylate copolymer having a weight average molecular weight in a range of 150,000 to 400,000 Da, wherein the curable (meth)acrylate copolymer comprises:
a) a first monomeric unit of Formula (I) in an amount in a range of 50 to 94 weight percent based on a total weight of monomeric units in the curable (meth)acrylate copolymer

wherein
R 1 is hydrogen or methyl; and
R 2 is an alkyl, heteroalkyl, aryl, aralkyl, or alkaryl group;

b) a second monomeric unit of Formula (II) in an amount in a range of 6 to 10 weight percent based on the total weight of monomeric units in the curable (meth)acrylate copolymer

wherein
R 1 is hydrogen or methyl;

c) a third monomeric unit of Formula (III) in an amount in a range of 0.05 to 5 weight percent based on the total weight of monomeric units of the curable (meth)acrylate copolymer

wherein
R 1 is hydrogen or methyl;
R 3 comprises an aromatic ketone group that causes hydrogen abstraction from a polymeric chain when exposed to ultraviolet radiation; and

d) a fourth monomeric unit of Formula (IV) in an amount in a range of 0.1 to 20 weight percent based on the total weight of monomeric units of the curable (meth)acrylate copolymer

wherein
R 1 is hydrogen or methyl;
X is —O— or —NH—;
R 4 is a hydroxy-substituted alkyl or hydroxy-substituted heteroalkyl group; and

wherein
the curable (meth)acrylate copolymer contains 0 to less than 0.1 weight percent of acidic monomeric units based on a total weight of the (meth)acylate copolymer;
the curable adhesive composition has a creep compliance that is less than 5(10 −4 ) inverse Pascals at 25° C.;
the curable adhesive composition has a creep compliance that is greater than 1(10 −3 ) inverse Pascals at 70° C.; and
the curable adhesive composition has a shear storage modulus equal to at least 40 kiloPascals (kPa) when measured at 25° C. and at a frequency of 1 radian/second.

2. The curable adhesive composition of claim 1 , wherein the curable (meth)acrylate copolymer further comprises a fifth monomeric unit that is a nitrogen-containing monomeric unit not of Formula (II).

3. The curable adhesive composition of claim 1 , wherein the curable (meth)acrylate copolymer is free or substantially free of monomeric units derived from a vinyl ester monomer or an anhydride-containing monomer.

4. The curable adhesive composition of claim 1 , wherein the curable (meth)acrylate copolymer has a glass transition temperature equal to at least −15° C. when measured using Dynamic Mechanical Analysis at a frequency of 1 radian/second.

5. A cured adhesive composition comprising a cured (meth)acrylate copolymer, the cured adhesive composition being a reaction product resulting from exposing a curable adhesive composition to ultraviolet or visible light radiation, wherein the curable adhesive composition is of claim 1 .

6. The cured adhesive composition of claim 5 , wherein the cured adhesive composition is optically clear.

7. An article comprising a first substrate and a layer of the curable adhesive composition of claim 1 positioned adjacent to the first substrate.

8. The article of claim 7 , wherein the layer of the curable adhesive composition is a die-cut film.

9. The article of claim 7 , wherein the first substrate is a release liner.

10. The article of claim 8 , wherein the article further comprises a second substrate and the die-cut film is positioned between the first substrate that is the release liner and a second substrate, the second substrate being a second release liner or an optical substrate.

11. An article comprising a first substrate, a second substrate, and a layer of the cured adhesive composition of claim 5 , wherein the layer of the cured adhesive composition is positioned between the first substrate and the second substrate.

12. A method of preparing an article, the method comprising:
providing a first substrate, a second substrate, and a curable adhesive composition layer of claim 1 ;
forming a laminate comprising the first substrate, the second substrate, and the curable adhesive composition layer, wherein the curable adhesive composition layer is positioned between the first substrate and the second substrate; and
exposing the curable adhesive composition layer to ultraviolet or visible light radiation to form a cured adhesive composition layer.

13. The method of claim 12 , wherein at least one of the first substrate and the second substrate has at least one feature and wherein forming the laminate comprises flowing the curable adhesive composition to cover an outer surface of the feature.

14. The method of claim 12 , wherein the curable adhesive composition layer is cut with a die to have dimensions suitable for positioning between the first substrate and the second substrate.

Assignees

• 3M Innovative Properties Company

Inventors

• Behling Ross E
• Clapper Jason D
• Everaerts Albert I
• Ting Chun-Yi
• Ellis Mark F
• Benson Karl E
• Xia Jianhui

Classifications

• C08F265/04

  on to polymers of esters · CPC title

• C08J2333/10

  Homopolymers or copolymers of methacrylic acid esters · CPC title

• C09J2433/00

  Presence of (meth)acrylic polymer · CPC title

• C08F220/1818

  C13or longer chain (meth)acrylate, e.g. stearyl (meth)acrylate · CPC title

• C08F220/1804 Primary

  C4-(meth)acrylate, e.g. butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate · CPC title