# US 2020/0399510 A1 · Pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet

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- Number: US 2020/0399510 A1
- Document ID: US20200399510A1
- Status: Published application
- Kind: A1
- Application number: 16/956,817
- Filed: 2018-12-27
- Published: 2020-12-24
- Earliest claimed: 2017-12-28
- Assignees: Nitto Denko Corporation
- Applicants: Nitto Denko Corporation
- Inventors: Kenji FURUTA; Tatsuya SUZUKI; Minami WATANABE
- Web page: https://patentgrep.com/patent/US20200399510A1

## CPC

- C09J 119/00: Adhesives based on rubbers, not provided for in groups C09J107/00 - C09J117/00
- C09J 123/22: Copolymers of isobutene; Butyl rubber {; Homo- or copolymers of other iso-olefines}
- B32B 27/00: Layered products comprising {a layer of} synthetic resin {(fibrous or filamentary layer made of a synthetic resin B32B5/02; particulate layer made of a synthetic resin B32B5/16; foamed layer made of a synthetic resin B32B5/18)}
- C09J 7/38: Pressure-sensitive adhesives [PSA]
- C09J 7/383: {Natural or synthetic rubber}
- C09J 7/385: {Acrylic polymers}
- C09J 109/00: Adhesives based on homopolymers or copolymers of conjugated diene hydrocarbons
- G01N 19/10: Measuring moisture content, e.g. by measuring change in length of hygroscopic filament; Hygrometers
- G11B 33/14: Reducing influence of physical parameters, e.g. temperature change, moisture, dust
- G11B 33/1406: {Reducing the influence of the temperature}
- G11B 33/1486: {Control/regulation of the pressure, e.g. the pressure inside the housing of a drive}
- H05K 5/061: {sealed by a gasket held between a removable cover and a body, e.g. O-ring, packing}
- C08L 2205/025: containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
- C09J 2203/326: for bonding electronic components such as wafers, chips or semiconductors
- C09J 2301/302: the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C
- C09J 2409/00: Presence of diene rubber
- C09J 2433/00: Presence of (meth)acrylic polymer
- G11B 2005/0021: {Thermally assisted recording using an auxiliary energy source for heating the recording layer locally to assist the magnetization reversal}
- 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)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

Provided is a PSA composition capable of achieving excellent moisture resistance. The PSA composition provided by the present invention comprises a polymer A and a polymer B different from the polymer A. In each of the polymer A and the polymer B, isobutylene is polymerized at a ratio of 50% by weight or higher.

## Claims

### Claim 1

A pressure-sensitive adhesive composition comprising a polymer A and a polymer B different from the polymer A, wherein
in each of the polymer A and the polymer B, isobutylene is polymerized at a ratio of 50% by weight or higher.

### Claim 2 (depends on 1)

The pressure-sensitive adhesive composition according to claim 1, wherein, in addition to the isobutylene, isoprene is copolymerized in the polymer B.

### Claim 3 (depends on 1)

The pressure-sensitive adhesive composition according to claim 1, wherein the polymer A has a weight average molecular weight in the range between 1×104 and 80×104.

### Claim 4 (depends on 1)

The pressure-sensitive adhesive composition according to claim 1, wherein the polymer B has a weight average molecular weight in the range between 5×104 and 150×104.

### Claim 5 (depends on 1)

The pressure-sensitive adhesive composition according to claim 1, wherein the polymer A has a weight average molecular weight MA and the polymer B has a weight average molecular weight MB, with a MB/MA ratio value in the range between 5 and 100.

### Claim 6 (depends on 1)

The pressure-sensitive adhesive composition according to claim 1, having a weight ratio (CA/CB) of polymer A content CA to polymer B content CB (a weight ratio of the polymer A to the polymer B) in the range between 70/30 and 30/70.

### Claim 7 (depends on 1)

The pressure-sensitive adhesive composition according to claim 1, wherein the polymer A and the polymer B has a combined amount accounting for 90% by weight or more of solid content of the pressure-sensitive adhesive composition.

### Claim 8 (depends on 1)

The pressure-sensitive adhesive composition according to claim 1, used for sealing an internal space of a magnetic disc device.

### Claim 9

A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer comprising a polymer A and a polymer B different from the polymer A, wherein
in each of the polymer A and the polymer B, isobutylene is polymerized at a ratio of 50% by weight or above.

### Claim 10 (depends on 9)

The pressure-sensitive adhesive sheet according to claim 9, wherein the pressure-sensitive adhesive layer has a storage modulus at 25° C., G′(25° C.), of 0.09 MPa or greater and 0.29 MPa or less.