# US 8,785,530 B2 · Crosslinkable rubber composition and cross-linked rubber

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- Number: US 8,785,530 B2
- Document ID: US8785530B2
- Status: Granted
- Kind: B2
- Application number: 13/714,699
- Filed: 2012-12-14
- Published: 2013-04-25
- Granted: 2014-07-22
- Earliest claimed: 2005-12-21
- Assignees: Zeon Corporation
- Applicants: Zeon Corporation
- Inventors: Hiroyasu Nagamori; Shigeru Fujita; Kiyonori Umetsu; Akira Tsukada
- Web page: https://patentgrep.com/patent/US8785530B2

## CPC

- C08L 15/005: {Hydrogenated nitrile rubber}
- C08K 5/005: {Stabilisers against oxidation, heat, light, ozone}
- C08K 5/17: Amines; Quaternary ammonium compounds
- C08K 5/18: with aromatically bound amino groups
- C08L 33/20: Homopolymers or copolymers of acrylonitrile (C08L55/02 takes precedence)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

A crosslinkable rubber composition comprising 0.2 to 10 parts by weight of an aromatic secondary amine-based anti-aging agent and 0.5 to 20 parts by weight of a polyamine-based crosslinking agent with respect to 100 parts by weight of a nitrile rubber including an α,β-ethylenically unsaturated nitrile unit and an α,β-ethylenically unsaturated dicarboxylic acid monoester unit, and with iodine value of 120 or less. The present invention can provide a crosslinkable rubber composition, providable of a cross-linked rubber excellent in a variety of properties such as mechanical strength and small in compression set, and a cross-linked rubber obtained by cross-linking the rubber composition.

## Claims

### Claim 1

A crosslinkable rubber composition comprising
0.2 to 20 parts by weight of a polyamine-based crosslinking agent
with respect to a total of 100 parts by weight of a nitrile group containing highly saturated copolymer rubber having an α,β-ethylenically unsaturated dicarboxylic acid monoester monomer unit and an acrylic rubber having an α,β-ethylenically unsaturated dicarboxylic acid monoester monomer unit but substantially not containing methacrylonitrile unit.

### Claim 2 (depends on 1)

The crosslinkable rubber composition as set forth in claim 1, wherein a monomer forming said α,β-ethylenically unsaturated dicarboxylic acid monoester monomer unit of either the nitrile group containing highly saturated copolymer rubber or the acrylic rubber is a monoester monomer of a dicarboxylic acid having a carboxyl group in each of two carbon atoms forming an α,β-ethylenically unsaturated bond.

### Claim 3 (depends on 2)

The crosslinkable rubber composition as set forth in claim 2, wherein said monomer forming said α,β-ethylenically unsaturated dicarboxylic acid monoester monomer unit is a monoalkylester of maleic acid or a monoalkylester of fumaric acid.

### Claim 4 (depends on 1)

The crosslinkable rubber composition as set forth claim 1, wherein a weight ratio of said nitrile group containing highly-saturated copolymer rubber and said acrylic rubber is 5:95 to 95:5.

### Claim 5 (depends on 1)

The crosslinkable rubber composition as set forth in claim 1, capable of providing a cross-linked rubber, wherein O-ring compression set is 40% or less after maintaining the cross-linked rubber in a 25%-compressed state at 150° C. for 168 hours.

### Claim 6 (depends on 1)

The crosslinkable rubber composition as set forth in claim 1, further including 0.5 to 10 parts by weight of a basic crosslinking accelerator.

### Claim 7 (depends on 1)

A cross-linked rubber obtained by cross-linking the crosslinkable rubber composition as set forth in claim 1.

### Claim 8 (depends on 7)

The cross-linked rubber as set forth in claim 7, which is a seal material.

### Claim 9 (depends on 7)

The cross-linked rubber as set forth in claim 7, which is a belt material.

### Claim 10 (depends on 1)

The crosslinkable rubber composition as set forth in claim 1, wherein said acrylic rubber comprises an α,β-ethylenically unsaturated dicarboxylic acid monoester monomer unit and acrylic acid ester monomer unit, and optionally a monomer unit selected from the group consisting of an active chlorine group containing unsaturated monomer unit, an epoxy group containing monomer unit, a carboxyl group containing monomer unit other than the α,β-ethylenically unsaturated dicarboxylic acid monoester monomer unit, a diene-based monomer unit, ethylene unit, acrylonitrile unit, vinyl acetate unit, styrene unit, α-methylstyrene, acrylamide and polyalkylene glycol acrylic acid ester.

### Claim 11 (depends on 10)

The crosslinkable rubber composition as set forth in claim 10, wherein said acrylic rubber consists essentially of an α,β-ethylenically unsaturated dicarboxylic acid monoester monomer unit and acrylic acid ester monomer unit.

### Claim 12 (depends on 10)

A cross-linked rubber obtained by cross-linking the crosslinkable rubber composition as set forth in claim 10.

### Claim 13 (depends on 12)

The cross-linked rubber as set forth in claim 12, which is a seal material.

### Claim 14 (depends on 12)

The cross-linked rubber as set forth in claim 12, which is a belt material.

### Claim 15 (depends on 11)

A cross-linked rubber obtained by cross-linking the crosslinkable rubber composition as set forth in claim 11.

### Claim 16 (depends on 15)

The cross-linked rubber as set forth in claim 15, which is a seal material.

### Claim 17 (depends on 15)

The cross-linked rubber as set forth in claim 15, which is a belt material.