Pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet using same

Patent metadata

Field	Value
Publication number	US-9598616-B2
Application number	US-201414786872-A
Country	US
Kind code	B2
Filing date	Apr 23, 2014
Priority date	Apr 25, 2013
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

The invention provides a pressure-sensitive adhesive composition, which is prepared by using an alcohol solvent to obtain a high-molecular weight acrylic polymer, and exhibits excellent levels of coating liquid storage stability, stability over time in the adhesiveness, aging suitability, adhesive strength, releasability and heat-resistant holding power, as well as providing a pressure-sensitive adhesive sheet. The pressure-sensitive adhesive composition comprises a specific crosslinking agent and an acrylic polymer with a glass transition temperature of −60 to 0° C. obtained by radical polymerization in an alcohol solvent of an ethylenic unsaturated bond-containing monomer comprising specific amounts of specific monomers, wherein the acrylic polymer contains a low-molecular weight component and a high-molecular weight component with an area ratio therebetween of 65/35 to 80/20, and the monomer has a carboxyl group.

First claim

The invention claimed is:

1. A pressure-sensitive adhesive composition, comprising:
a crosslinking agent, and
an acrylic polymer with a glass transition temperature of −60° C. to 0° C. and obtained by radical polymerization in an alcohol solvent of an ethylenic unsaturated bond-containing monomer, the alcohol solvent comprising,
98.0% to 99.9% by weight of a monomer having one ethylenic unsaturated bond per molecule, and
0.1% to 2.0% by weight of a methacrylate monomer having two ethylenic unsaturated bonds per molecule;

wherein:
the acrylic polymer:
has two peak tops in a gel permeation chromatography (GPC) elution curve,
comprises a low-molecular weight component with a weight-average molecular weight of 10,000 to 200,000, and a high-molecular weight component with a weight-average molecular weight of 700,000 to 1,500,000, and
has an area ratio between the low-molecular weight component and the high-molecular weight component in GPC of 65/35 to 80/20,

the monomer (A) comprises a monomer having a carboxyl group, and
the crosslinking agent comprises an epoxy compound, a carbodiimide compound, or both.

2. The pressure-sensitive adhesive composition according to claim 1 , wherein a weight-average molecular weight of a combined total of the low-molecular weight component and the high-molecular weight component is from 200,000 to 500,000, and a ratio (Mw/Mn) between the weight-average molecular weight (Mw) and a number-average molecular weight (Mn) is from 3.0 to 10.0.

3. The pressure-sensitive adhesive composition according to claim 1 , wherein:
the acrylic polymer comprises carboxyl groups that are neutralized with an amine compound having a boiling point of 150° C. or lower, and
an amount of the amine compound is 1 mol to 3 mol per 1 mol of the carboxyl groups.

4. The pressure-sensitive adhesive composition according to claim 1 , wherein the crosslinking agent is an aqueous or water-dispersed carbodiimide compound.

5. A method for producing the pressure-sensitive adhesive composition according to claim 1 , comprising:
subjecting 100 parts by weight of the ethylenic unsaturated bond-containing monomer in 20 to 50 parts by weight of ethanol to radical polymerization to obtain the acrylic polymer.

6. The method according to claim 5 , wherein the ethylenic unsaturated bond-containing monomer is subjected to radical polymerization using a dropwise addition method.

7. A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to claim 1 .

Assignees

• Toyo Ink Sc Holdings Co Ltd

Inventors

• Sato Yuki
• Oya Toru
• Tone Yoshitaka
• Kobayashi Takayuki

Classifications

• C09J7/385

  Acrylic polymers · CPC title

• C08K5/17

  Amines; Quaternary ammonium compounds · CPC title

• C09J133/14

  of esters containing halogen, nitrogen, sulfur or oxygen atoms in addition to the carboxy oxygen · CPC title

• C08K5/20

  Carboxylic acid amides · CPC title

• C09J133/08 Primary

  Homopolymers or copolymers of acrylic acid esters · CPC title