Adhesive containing block copolymer

Patent metadata

Field	Value
Publication number	US-9683148-B2
Application number	US-201414890336-A
Country	US
Kind code	B2
Filing date	May 9, 2014
Priority date	May 13, 2013
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

An adhesive containing a block copolymer having at least one structure represented by formula: -[A1]-[B/A2]-, where [A1] represents a polymer block composed of a structural unit derived from a methacrylic acid ester (A1), [B/A2] represents a copolymer block composed of a structural unit derived from an acrylic acid ester (B) and a structural unit derived from a methacrylic acid ester (A2), and the copolymer block [B/A2] has a gradient copolymer block section in which a copolymerization ratio of the methacrylic acid ester (A2) continuously increases from a section connected to the polymer block [A1]. The block copolymer has a total content of the structural units derived from the methacrylic acid ester (A1) and the methacrylic acid ester (A2) of 5% to 60% by mass, a weight-average molecular weight (Mw) of 30,000 to 300,000, and a molecular weight distribution (Mw/Mn) of 1.0 to 1.5.

First claim

The invention claimed is:

1. An adhesive comprising:
a block copolymer comprising at least one structure represented by formula (I):
-[A1]-[B/A2]-  (I)

wherein, in formula (I):
[A1] represents a polymer block comprising a structural unit derived from a methacrylic acid ester (A1), and
[B/A2] represents a copolymer block comprising a structural unit derived from an acrylic acid ester (B) and a structural unit derived from a methacrylic acid ester (A2), and the copolymer block [B/A2] comprises a gradient copolymer block section in which a copolymerization ratio of the methacrylic acid ester (A2) continuously increases from a section connected to the polymer block [A1];
wherein the block copolymer comprises:
a total content of the structural units derived from the methacrylic acid ester (A1) and the methacrylic acid ester (A2) of 5% to 60% by mass,
a weight-average molecular weight (Mw) of 30,000 to 300,000, and
a molecular weight distribution (Mw/Mn) of 1.0 to 1.5.

2. The adhesive according to claim 1 , wherein the block copolymer is represented by formula (II):
[A1]-[B/A2]  (II).

3. The adhesive according to claim 1 , wherein, in the block copolymer, a ratio of a monomer sequence distribution represented by formula (III) is 0.10 to 0.70:
AAB/(AAB+BAB)  (III)

wherein, in formula (III):
AAB represents a ratio of a triad monomer sequence of methacrylic acid ester (A)-methacrylic acid ester (A)-acrylic acid ester (B) in the block copolymer, and
BAB represents a ratio of a triad monomer sequence of acrylic acid ester (B)-methacrylic acid ester (A)-acrylic acid ester (B) in the block copolymer.

4. The adhesive according to claim 1 , wherein the block copolymer forms a microphase separation structure.

5. The adhesive according to claim 1 , wherein the polymer block [A1] has a glass transition temperature of 100° C. or higher, and the copolymer block [B/A2] has a glass transition temperature of 10° C. or lower.

6. The adhesive according to claim 1 , wherein the total content of the structural units derived from the methacrylic acid ester (A1) and the methacrylic acid ester (A2) is 5% to 32% by mass.

7. The adhesive according to claim 1 , wherein the molecular weight distribution (Mw/Mn) of the block copolymer is 1.0 to 1.3.

8. The adhesive according to claim 1 , wherein the methacrylic acid ester (A1) and the methacrlylic acid ester (A2) are each methyl methacrylate.

9. The adhesive according to claim 1 , wherein the acrylic acid ester (B) is a monomer selected from the group consisting of methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, acrylate, and a mixture thereof.

10. The adhesive according to claim 9 , wherein the acrylic acid ester (B) is a monomer mixture of two or more selected from the group consisting of methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, and n-octyl acrylate.

11. The adhesive according to claim 1 , wherein the polymer block [A1] has a triad syndiotacticity (rr) of 65% or more.

12. The adhesive according to claim 1 , wherein the block copolymer is obtained by anionic polymerization in the presence of an organoaluminum compound.

13. The adhesive according to claim 1 , further comprising at least one selected from the group consisting of acrylic resins, ethylene/vinyl acetate copolymer, acrylonitrile-styrene resin, polylactic acid and polyvinylidene fluoride.

14. The adhesive according to claim 1 , further comprising at least one tackifying resin selected from the group consisting of rosin-containing resins, terpene-containing resins, petroleum resins, styrene-based resins, coumarone-indene-containing resins, phenolic resins, and xylene resins.

15. The adhesive according to claim 1 , further comprising at least one selected from the group consisting of a plasticizer, heat stabilizer, light stabilizer, antistatic agent, flame retardant, blowing agent, colorant, dye, refractive index adjusting agent, filler, and curing agent.

16. A block copolymer, comprising:
at least one structure represented by formula (I):
-[A1]-[B/A2]-  (I)

wherein, in formula (I):
[A1] represents a polymer block comprising a structural unit derived from a methacrylic acid ester (A1), and
[B/A2] represents a copolymer block comprising a structural unit derived from an acrylic acid ester (B) and a structural unit derived from a methacrylic acid ester (A2), and the copolymer block [B/A2] comprises a gradient copolymer block section in which a copolymerization ratio of the methacrylic acid ester (A2) continuously increases from a section connected to the polymer block [A1]:
wherein the block copolymer comprises:
a total content of the structural units derived from the methacrylic acid ester (A1) and the methacrylic acid ester (A2) of 5% to 60% by mass,
a weight-average molecular weight (Mw) of 30,000 to 300,000, and
a molecular weight distribution (Mw/Mn) of 1.0 to 1.5.

Assignees

• Kuraray Co

Inventors

• Nakada Kanayo
• Morishita Yoshihiro

Classifications

• C08F293/005

  using free radical "living" or "controlled" polymerisation, e.g. using a complexing agent · CPC title

• C09J153/00 Primary

  Adhesives based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers · CPC title

• C08F4/52

  selected from boron, aluminium, gallium, indium, thallium or rare earths (C08F4/14 takes precedence) · CPC title

• C08F297/026

  polymerising acrylic acid, methacrylic acid or derivatives thereof · CPC title

• C08F220/14

  Methyl esters {, e.g. methyl (meth)acrylate} · CPC title