# US RE31,322 E · Process for producing sulfur-curable acrylic rubbers

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US RE31,322 E
- Document ID: USRE31322E
- Status: Granted
- Kind: E
- Application number: 06/304,788
- Filed: 1981-09-23
- Granted: 1983-07-26
- Earliest claimed: 1978-03-27
- Assignees: Nippon Zeon Co., Ltd.
- Inventors: Tetsu Ohishi; Kohichi Handa; Haruo Ueno
- Web page: https://patentgrep.com/patent/USRE31322E

## Abstract

A process for producing a sulfur-curable acrylic rubber is provided which comprises radical-copolymerizing (1) an alkyl acrylate with (2) an alkenyl acrylate or methacrylate, or radical-copolymerizing (1) an alkyl acrylate, (2) an alkenyl acrylate or methacrylate, (3) an alkoxyalkyl acrylate and optionally (4) acrylonitrile. These acrylic rubbers can be cured at a rate as fast as those for curing diene-type rubbers, and the cured products exhibit superior properties without long heat-treatment after curing.

## Claims

### Claim 1

A process for producing a sulfur-curable acrylic rubber, which comprises copolymerizing in the presence of a radical initiator
(1) 90 to 99.5% by weight of at least one alkyl acrylate with the alkyl group containing 1 to 8 carbon atoms, and
(2) 0.5 to 10% by weight of at least one monomer of the general formula ##STR3## wherein R.sub.1 represents a hydrogen atom or a methyl group, and R.sub.2 and R.sub.3, independently from each other, represent an alkyl group containing 1 to 3 carbon atoms.

### Claim 2

A process for producing a sulfur-curable acrylic rubber, which comprises copolymerization in the presence of a radical initiator
(1) 30 to 89.5% by weight of at least one alkyl acrylate with the alkyl group containing 1 to 8 carbon atoms,
(2) 0.5 to 10% by weight of at least one monomer of the general formula ##STR4## wherein R.sub.1 represents a hydrogen atom or a methyl group, and R.sub.2 and R.sub.3, independently from each other, represent an alkyl group containing 1 to 3 carbon atoms,
(3) 10 to 60% by weight of at least one alkoxyalkyl acrylate with the alkoxy group containing 1 to 4 carbon atoms and the alkylene group containing 1 to 4 carbon atoms, and
(4) 0 to 30% by weight of acrylonitrile.

### Claim 3 (depends on 1, 2)

The process of claim 1 or 2 wherein the monomer (2) represented by the general formula is 3-methyl-2-butenyl acrylate.

### Claim 4 (depends on 1, 2)

The process of claim 1 or 2 wherein the monomer (2) represented by the general formula is 3-methyl-2-butenyl methacrylate.

### Claim 5 (depends on 1, 2)

The process of claim 1 or 2 wherein the copolymerization is carried out in emulsion.

### Claim 6 (depends on 1, 2)

The process of claim 1 or claim 2 wherein the alkyl group of the alkyl acrylate contains 2 to 4 carbon atoms.

### Claim 7 (depends on 1, 2)

The process of claim 1 or claim 2 wherein the monomer (2) is present in an amount of from about 2% to about 6% by weight.

### Claim 8 (depends on 2)

The process of claim 2 wherein the alkoxyacrylate is present in an amount of from about 20% to about 50% by weight.

### Claim 9 (depends on 2)

The process of claim 2 wherein acrylonitrile is present in an amount of from about 2% to about 20% by weight.

### Claim 10 (depends on 1, 2)

The process of claim 1 or claim 2 wherein the radical initiator is p-menthane hydroperoxide.