(Meth)acrylic copolymer, adhesive composition containing same, and adhesive sheet

Patent metadata

Field	Value
Publication number	US-10570237-B2
Application number	US-201415039623-A
Country	US
Kind code	B2
Filing date	Nov 28, 2014
Priority date	Nov 29, 2013
Publication date	Feb 25, 2020
Grant date	Feb 25, 2020

Abstract

A (meth)acrylic copolymer (A) having a mass average molecular weight of 50,000 to 1,000,000, in which the (meth)acrylic copolymer (A) is obtained by polymerizing a monomer mixture including a macromonomer (a) that has a number average molecular weight of 500 or more and less than 6000 and a vinyl monomer (b), and preferably includes 7 to 40% by mass of a repeat unit derived from the macromonomer (a), has sufficient coating workability, adhesive holding power and adhesive property as an adhesive composition.

First claim

The invention claimed is:

1. An adhesive composition comprising a (meth)acrylic copolymer (A) having a mass average molecular weight of 50,000 to 1,000,000,
wherein the (meth)acrylic copolymer (A) is obtained by polymerizing a monomer mixture comprising a macromonomer (a) having a number average molecular weight of 1,900 or more and 4,500 or less and a vinyl monomer (b),
wherein the monomer (a) is represented by Formula (1):

where in Formula (1),
n is 4 to 5,999;
each of R and R 1 to R n is independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or a heterocyclic group, in which the alkyl group, the cycloalkyl group, the aryl group or the heterocyclic group optionally have a substituent;
each of X 1 to X n is independently a hydrogen atom or a methyl group; and
Z is a terminal group of the macromonomer (a),
wherein the (meth)acrylic copolymer (A) comprises 7 to 30% by mass of a repeat unit derived from the macromonomer (a),
wherein the adhesive composition is in a solution state in the presence of at least one of a solvent and a liquid vinyl monomer, or is a hot melt-based adhesive composition without solvent.

2. The adhesive composition according to claim 1 , wherein the (meth)acrylic copolymer (A) comprises 9 to 20% by mass of a repeat unit derived from the macromonomer (a).

3. The adhesive composition according to claim 1 , wherein the glass transition temperature (Tga) of the macromonomer (a) is 30 to 120° C.

4. The adhesive composition according to claim 1 , wherein the melt viscosity at 130° C. of the (meth)acrylic copolymer (A) is 20 to 800 Pa·s.

5. An adhesive sheet using the adhesive composition according to claim 1 .

6. The adhesive composition according to claim 2 , wherein the glass transition temperature (Tga) of the macromonomer (a) is 30 to 120° C.

7. The adhesive composition according to claim 2 , wherein the (meth)acrylic copolymer (A) has a melt viscosity at 130° C. of 20 to 800 Pa·s.

8. The adhesive composition according to claim 3 , wherein the (meth)acrylic copolymer (A) has a melt viscosity at 130° C. of 20 to 800 Pa·s.

9. An adhesive sheet using the adhesive composition according to claim 2 .

10. An adhesive sheet using the adhesive composition according to claim 3 .

11. An adhesive sheet using the adhesive composition according to claim 4 .

12. An adhesive sheet using the adhesive composition according to claim 8 .

13. The adhesive composition according to claim 1 , wherein the macromonomer (a) has a number average molecular weight of 3,500 or less.

14. The adhesive composition according to claim 1 , wherein the macromonomer (a) has a number average molecular weight of 2,600 or less.

15. The adhesive composition according to claim 1 , wherein the terminal group of the macromonomer (a) is selected from the group consisting of a methacryloyl group, an acryloyl group, a vinyl group and a terminal polymerizable functional group represented by the following Formula (2):

wherein R z represents R, R 1 to R n in Formula (1).

16. The adhesive composition according to claim 1 , wherein
the macromonomer (a) is obtained from methyl (meth)acrylate and isobornyl (meth)acrylate.

17. The adhesive composition according to claim 16 , wherein
a ratio of methyl (meth)acrylate to isobornyl (meth)acrylate is approximately 50/50.

Assignees

• Mitsubishi Rayon Co
• Mitsubishi Chem Corp

Inventors

• Kawai Eri
• Nakamura Junichi
• Shinada Hiroko

Classifications

• C08L33/10

  Homopolymers or copolymers of methacrylic acid esters · CPC title

• C09J7/00

  Adhesives in the form of films or foils · CPC title

• C09J151/003

  grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds (C09J151/04, C09J151/06 take precedence) · CPC title

• C08F222/103

  of trialcohols, e.g. trimethylolpropane tri(meth)acrylate · CPC title

• C09J4/00

  Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond {; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16} · CPC title