# US 10,479,058 B2 · Pressure-sensitive adhesive sheet

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- Number: US 10,479,058 B2
- Document ID: US10479058B2
- Status: Granted
- Kind: B2
- Application number: 15/502,276
- Filed: 2015-07-14
- Published: 2017-08-17
- Granted: 2019-11-19
- Earliest claimed: 2014-08-08
- Assignees: Nitto Denko Corporation
- Applicants: Nitto Denko Corporation
- Inventors: Kenichi Nishikawa; Takuma Ogawa
- Web page: https://patentgrep.com/patent/US10479058B2

## CPC

- B32B 27/308: {comprising acrylic (co)polymers}
- B32B 3/26: characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids {(foam layer B32B5/18; layer of synthetic resin characterised by fillers that create voids or cavities B32B27/205); characterised by an apertured layer}
- B32B 7/12: using interposed adhesives or interposed materials with bonding properties
- B32B 27/08: of synthetic resin
- B32B 27/20: using fillers, pigments, thixotroping agents
- B32B 27/30: comprising vinyl {(co)polymers; comprising acrylic (co)polymers}
- C08L 33/08: Homopolymers or copolymers of acrylic acid esters
- C08L 93/00: Compositions of natural resins; Compositions of derivatives thereof (of polysaccharides C08L1/00 - C08L5/00; of natural rubber C08L7/00)
- C08L 93/04: Rosin
- C09J 7/20: characterised by their carriers
- C09J 7/24: based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
- C09J 7/385: {Acrylic polymers}
- C09J 11/08: Macromolecular additives
- C09J 133/00: Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
- C09J 133/08: Homopolymers or copolymers of acrylic acid esters
- B32B 2264/101: Glass
- B32B 2405/00: Adhesive articles, e.g. adhesive tapes
- C09J 2301/414: presence of a copolymer
- C09J 2433/00: Presence of (meth)acrylic polymer
- C09J 2433/006: in the substrate
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- 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)

## Abstract

Provided is a PSA sheet that shows high peel strength to low polar adherends while having excellent flexibility. This invention provides a PSA sheet that comprises a PSA layer (A) constituting an adhesive face and a viscoelastic layer (B) supporting the PSA layer (A). In the PSA sheet, the viscoelastic layer (B) comprises hollow particles or have bubbles. The PSA layer (A) comprises an acrylic polymer (a) as the base polymer. The copolymerization ratio of an acidic group-containing monomer in the acrylic polymer (a) is 5% by weight or lower.

## Claims

### Claim 1

A pressure-sensitive adhesive sheet comprising:
a pressure-sensitive adhesive layer (A) constituting an adhesive face, and
a viscoelastic layer (B) supporting the pressure-sensitive adhesive layer (A);
wherein
the viscoelastic layer (B) comprises hollow particles or have bubbles,
the viscoelastic layer (B) further comprises, as its base polymer, an acrylic polymer (b) obtained by polymerizing a starting monomer mixture that comprises an acidic group-containing monomer,
the pressure-sensitive adhesive layer (A) comprises an acrylic polymer (a) as its base polymer,
a glass transition temperature of the acrylic polymer (a) is −60° C. to −25° C.,
an acidic group-containing monomer is copolymerized in the acrylic polymer (a) at a ratio of 5% by weight or lower,
the acrylic polymer (a) has a dispersity (Mw/Mn) of 3 to 10, and
wherein a weight ratio (ACb/ACa) of the acidic group-containing monomer in the acrylic polymer (b) to the acidic group-containing monomer in the acrylic polymer (a) is 2 or higher and 10 or lower wherein the adhesive face exhibits a 90° peel strength to polypropylene of 30 N/25 mm.

### Claim 2 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1 wherein the pressure-sensitive adhesive layer (A) comprises at least one species of tackifier selected from the group consisting of a rosin-based tackifier resin, a terpene-based tackifier resin and a phenolic tackifier resin.

### Claim 3 (depends on 2)

The pressure-sensitive adhesive sheet according to claim 2 wherein the pressure-sensitive adhesive layer (A) comprises 10 parts to 50 parts by weight of the tackifier to 100 parts by weight of the base polymer.

### Claim 4 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1 wherein the ratio (TB/TA) of the thickness TB of the viscoelastic layer (B) to the thickness TA of the pressure-sensitive adhesive layer (A) is 12 or higher.

### Claim 5 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1, wherein the viscoelastic layer (B) comprises the hollow particles, and the hollow particles have a diameter of 40 μm or higher.

### Claim 6 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1, wherein the acrylic polymer (a) further comprises a functional group-containing monomer selected from the group consisting of a hydroxyl group-containing monomer, an amide group-containing monomer, a cyano group-containing monomer, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, an oxazoline group-containing monomer, an aziridine group-containing monomer, an amino group-containing monomer, an epoxy group-containing monomer, a keto group-containing monomer, an isocyanate group-containing monomer, and an alkoxysilyl group-containing monomer.

### Claim 7 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1, wherein the acrylic polymer (a) is obtained by polymerizing a starting monomer mixture that consists essentially of an alkyl (meth)acrylate, the acidic group-containing monomer, and optionally at least one hydroxyl group-containing monomer and vinyl ester monomer.

### Claim 8 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1, wherein the acrylic polymer (a) comprises 90% by weight or more of an alkyl (meth)acrylate monomer based on all the monomers forming the acrylic polymer (a).

### Claim 9 (depends on 1)

The pressure-sensitive adhesive sheet according to claim 1 wherein the acrylic polymer (a) has the dispersity (Mw/Mn) of 4 to 10.