# US 4,394,472 A · Stabilized polyisoprene composition

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- Number: US 4,394,472 A
- Document ID: US4394472A
- Status: Granted
- Kind: A
- Application number: 06/332,827
- Filed: 1981-12-21
- Granted: 1983-07-19
- Earliest claimed: 1980-12-25
- Assignees: Japan Synthetic Rubber Co., Ltd.
- Inventors: Tadahiko Ito; Toshio Arao; Nobuo Satoh; Hiroshi Harada
- Web page: https://patentgrep.com/patent/US4394472A

## CPC

- C08K 5/3492: Triazines
- C08K 5/526: with hydroxyaryl compounds
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

A stabilized polyisoprene composition comprising 100 parts by weight of polyisoprene and 0.15-3.0 parts by weight of a binary system antioxidant consisting of 50-99% by weight of a phosphite type antioxidant represented by the formula, ##STR1## wherein R.sub.1, R.sub.2, and R.sub.3 are same or different aryl groups, and 50-1% by weight of a triazine derivative type antioxidant represented by the formula, ##STR2## wherein X.sub.1, X.sub.2, and X.sub.3, which may be the same or different, are selected from the group consisting of --NH--, --O--, and --S--, and R', R", and R"', which may be the same or different, represent alkyl, or alkyl-substituted or unsubstituted hydroxyphenyl groups. This binary system antioxidant exhibits a synergistic effect on the stabilization of polyisoprene against heat and oxygen.

## Claims

### Claim 1

A stabilized polyisoprene composition comprising 100 parts by weight of polyisoprene and 0.15-3.0 parts by weight of a binary system antioxidant consisting of a phosphite type antioxidant represented by the formula: ##STR7## wherein R.sub.1, R.sub.2 and R.sub.3, which may be the same or different, represent aryl or alkaryl groups having 6 to 33 carbon atoms, and
a triazine derivative type antioxidant represented by the formula ##STR8## wherein X.sub.1, X.sub.2 and X.sub.3, which may be the same or different, are selected from the group consisting of --NH--, --O--, and --S--, and R', R", and R"', which may be the same or different, represent alkyl groups having 2 to 15 carbon atoms, or alkyl-substituted or unsubstituted hydroxyphenyl groups having 1 to 10 carbon atoms in the alkyl group,
or 2,4,6-tris (3',5'-di-t-butyl-4'-hydroxyphenylethoxy)-1,3,5-trizaine,
wherein the weight ratio of the phosphite type antioxidant to the triazine derivative type antioxidant is 70/10-95/5.

### Claim 2 (depends on 1)

A stabilized polyisoprene composition according to claim 1, wherein the aryl or alkaryl groups for R.sub.1, R.sub.2 and R.sub.3 have 15 to 24 carbon atoms, the alkyl groups for R', R" and R"' have 4 to 12 carbon atoms and the alkyl-substituted hydroxyphenyl groups for R', R" and R"' have 1 to 6 carbon atoms in the alkyl group.

### Claim 3 (depends on 1)

A stabilized polyisoprene composition according to claim 1, wherein the proportion of the binary system antioxidant is 0.2-1.0 part by weight per 100 parts by weight of polyisoprene.

### Claim 4 (depends on 1, 3)

A stabilized polyisoprene composition according to claim 1 or 3, wherein the phosphite type antioxidant is tris(nonylphenyl) phosphite, tris(bi-mono- and di-nonylphenyl) phosphite, tris(mono- and bi-di-nonylphenyl) phosphite, tris(di-nonylphenyl) phosphite, tris(dicyclohexylphenyl) phosphite, triphenyl phosphite, tris(di-t-butylphenyl) phosphite, or tris(di-octylphenyl) phosphite.

### Claim 5 (depends on 1, 3)

A stabilized polyisoprene composition according to claim 1 or 3 wherein the phosphite type antioxidant is tris(nonylphenyl) phosphite or tris(mono- and di-nonylphenyl) phosphite.

### Claim 6 (depends on 1, 3)

A stabilized polyisoprene composition according to claim 1 or 3, wherein the triazine derivative type antioxidant is 6-(4'-hydroxy-3',5'-di-t-butylanilino)-2,4-bis(octylthio)-1,3,5-triazine, 6-(4'-hydroxy-3',5'-dimethylanilino)-2,4-bis(octylthio)-1,3,5-triazine, 6-(4'-hydroxy-3'-methyl-5'-t-butylanilino)-2,4-bis(octylthio)-1,3,5-triazi ne, 2-octylthio-4,6-bis(3',5'-di-t-butyl-4'-hydroxyanilino)-1,3,5-triazine, 2-octylthio-4,6-bis(3',5'-di-hydroxyphenoxy)-1,3,5-triazine, 2,4,6-tris(3',5'-di-t-butyl-4'-hydroxyphenoxy)-1,3,5-triazine, or 2,4,6-tris(3',5'-di-t-butyl-4'-hydroxyphenylethoxy)-1,3,5-triazine.

### Claim 7 (depends on 5)

A stabilized polyisoprene composition according to claim 5, wherein the triazine derivative type antioxidant is 6-(4'-hydroxy-3',5'-di-t-butylanilino)-2,4-bis(octylthio)-1,3,5-triazine.

### Claim 8 (depends on 1)

A stabilized polyisoprene composition according to claim 1, wherein the polyisoprene is a synthetic cis-1,4-polyisoprene having a cis-1,4 configuration content of 80% or more.

### Claim 9 (depends on 1)

A stabilized polyisoprene composition according to claim 1, wherein the polyisoprene is a mixture of a synthetic cis-1,4-polyisoprene having a cis-1,4 configuration content of 80% or more and natural rubber.