# US 10,308,844 B2 · Pressure-sensitive adhesive, pressure-sensitive adhesive layer, and pressure-sensitive adhesive sheet

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- Number: US 10,308,844 B2
- Document ID: US10308844B2
- Status: Granted
- Kind: B2
- Application number: 14/115,228
- Filed: 2012-04-23
- Published: 2014-03-06
- Granted: 2019-06-04
- Earliest claimed: 2011-05-02
- Assignees: Nitto Denko Corporation
- Applicants: Masatsugu Higashi; Akiko Tanaka; Aimi Matsuura; Kiyoe Shigetomi; Tetsuo Inoue
- Inventors: Masatsugu Higashi; Akiko Tanaka; Aimi Matsuura; Kiyoe Shigetomi; Tetsuo Inoue
- Web page: https://patentgrep.com/patent/US10308844B2

## CPC

- C09J 135/02: Homopolymers or copolymers of esters (C09J135/06, C09J135/08 take precedence)
- C09J 4/06: {Organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond} in combination with a macromolecular compound other than an unsaturated polymer of groups C09J159/00 - C09J187/00
- C09J 7/22: Plastics; Metallised plastics
- C09J 7/385: {Acrylic polymers}
- C09J 133/066: {containing -OH groups}
- C09J 133/08: Homopolymers or copolymers of acrylic acid esters
- C09J 133/10: Homopolymers or copolymers of methacrylic acid esters
- C08F 220/1818: {C13or longer chain (meth)acrylate, e.g. stearyl (meth)acrylate}
- C08F 220/26: Esters containing oxygen in addition to the carboxy oxygen
- C08K 5/0025: {Crosslinking or vulcanising agents; including accelerators}
- C08K 5/103: with polyalcohols
- C09J 2203/318: for the production of liquid crystal displays
- C09J 2301/302: the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C
- C09J 2301/312: parameters being the characterizing feature
- C09J 2301/40: characterized by the presence of essential components
- C09J 2400/00: Presence of inorganic and organic materials
- C09J 2433/00: Presence of (meth)acrylic polymer
- G02B 5/30: Polarising elements (light-modulating devices with active elements G02F1/00)
- Y10T 428/2891: including addition polymer from alpha-beta unsaturated carboxylic acid [e.g., acrylic acid, methacrylic acid, etc.] Or derivative thereof
- C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A pressure-sensitive adhesive of the invention include a (meth)acryl-based polymer obtained by polymerization of a monomer component including 19 to 99.5% by weight of an alkyl (meth)acrylate having a branched alkyl group of 10 to 24 carbon atoms at an ester end. The pressure-sensitive adhesive has a satisfactory level of adhesive performance and can form a pressure-sensitive adhesive layer with a lower dielectric constant.

## Claims

### Claim 1

A pressure-sensitive adhesive sheet, comprising a transparent conductive film as a support and a pressure-sensitive adhesive layer formed on at least one surface of the transparent conductive film,
wherein the transparent conductive film comprises a metal thin layer and a transparent plastic film substrate, wherein the pressure-sensitive adhesive layer is formed on a surface of the metal thin layer,
wherein the pressure-sensitive adhesive layer is obtained from a pressure-sensitive adhesive composition,
wherein the pressure-sensitive adhesive composition comprises a (meth)acryl-based polymer obtained by polymerization of a monomer component including 19 to 45% by weight of an alkyl (meth)acrylate having a branched alkyl group of 14 to 24 carbon atoms at an ester end, and
wherein the branched alkyl group of 14 to 24 carbon atoms has a t-butyl group.

### Claim 2 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1, wherein the monomer component further includes 0.1 to 30% by weight of at least one functional group-containing monomer selected from a carboxyl group-containing monomer, a hydroxyl group-containing monomer, and a cyclic ether group-containing monomer.

### Claim 3 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1, wherein the monomer component further includes 0.5% or more by weight of at least one selected from an alkyl (meth)acrylate having a branched alkyl group of 3 to 9 carbon atoms at an ester end, an alkyl (meth)acrylate having a linear alkyl group of 1 to 24 carbon atoms at an ester end and an alkyl (meth)acrylate having a cyclic alkyl group at an ester end.

### Claim 4 (depends on 1)

The pressure-sensitive adhesive sheet according claim 1, wherein the monomer component further contains a polyfunctional monomer, in amount up to 3% by weight.

### Claim 5 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1, wherein the monomer component further comprises 0.01 to 5 parts by weight of a crosslinking agent based on 100 parts by weight of the (meth)acryl-based polymer.

### Claim 6 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer has a relative dielectric constant of 3.5 or less at a frequency of 100 kHz.

### Claim 7 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer has a gel fraction of 20 to 98% by weight.

### Claim 8 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer has a haze of 2% or less when having a thickness of 25 μm.

### Claim 9 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1 , which has an adhesive strength of 0.5 N/20 mm or more to alkali glass at a peel angle of 90° and a peel rate of 300 mm/minute.

### Claim 10 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1, wherein the (meth)acryl-based polymer is obtained by radiation polymerization of the monomer component.

### Claim 11 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1, wherein the alkyl (meth)acrylate comprises at least one monomer selected from isomyristyl (meth)acrylate, isostearyl (meth)acrylate, isopentadecyl (meth)acrylate, isohexadecyl (meth)acrylate, and isoheptadecyl (meth)acrylate.

### Claim 12 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1, wherein the alkyl (meth)acrylate is a t-butyl group-containing isostearyl acrylate represented by the following formula: