# US 5,710,205 A · Composition of fluoropolymers

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- Number: US 5,710,205 A
- Document ID: US5710205A
- Status: Granted
- Kind: A
- Application number: 08/618,391
- Filed: 1996-03-19
- Granted: 1998-01-20
- Earliest claimed: 1992-09-10
- Assignees: Imperial Chemical Industries PLC
- Inventors: Mark Davies; Paul Martin Hatton
- Web page: https://patentgrep.com/patent/US5710205A

## CPC

- C08L 27/18: Homopolymers or copolymers or tetrafluoroethene
- C08L 81/02: Polythioethers; Polythioether-ethers
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

A wear-resistant solid fluoropolymer composition, e.g. of homo- and copolymers of tetrafluoroethylene (TFE), which has an extremely low coefficient of friction in dry sliding contact with metal, without the application of additional fluid lubricant, which composition comprises: a) a fluoropolymer, b) a poly(arylene sulphide) and c) another high aromatic polymer; and a process for preparing the foregoing solid fluoropolymer composition.

## Claims

### Claim 1

A solid fluoropolymer composition which comprises:
a) polytetrafluoroethylene (PTFE),
b) a poly(arylene sulphide) and
c) another aromatic polymer, at least 50 wt. % of which is made up of aromatic moieties linked by functional groups such as oxy, carbonyl, sulphonyl, sulphonyloxy, amino, imino and mixtures thereof
and wherein the PTFE is present as a sintered matrix and wherein a mixture of at least the PTFE and the poly(arylene sulphide) have been subjected to a heat treatment within the temperature range from 200.degree. C. to 400.degree. C. prior to sintering and wherein the PTFE provides at least 30 vol. % of the composition, the poly(arylene sulphide) provides up to 40 vol. % of the composition and the aromatic polymer provides up to 30 vol. % of the composition;
and wherein the volume ratio of the poly(arylene sulphide) to the aromatic polymer is in the range of from 5:1 to 1:2.

### Claim 2 (depends on 1)

A composition according to claim 1 wherein at least 80 wt. % of the aromatic polymer is made up of aromatic moieties.

### Claim 3 (depends on 1)

A composition according to claim 1 wherein the aromatic polymer comprises
a) a linear or branched polymer main chain of 1,4-phenylene aromatic diradicals,
b) linked by oxy, carbonyl, sulphonyl, sulphonyloxy, amino and imino, and mixtures thereof, and
the poly(arylene sulphide) is a linear or branched-chain poly(1,4-phenylene sulphide).

### Claim 4 (depends on 3)

A composition according to claim 3 which comprises 2 to 20 vol. % of linear or branched-chain poly(1,4-phenylene sulphide), 1 to 10 vol. % of aromatic polymer, and 70 to 97 vol. % of PTFE relative to the total composition, and the poly(1,4-phenylene sulphide) and the aromatic polymer are present in a volume ratio in the range of from 4:1 to 1:1.

### Claim 5 (depends on 1)

A composition according to claim 1 wherein the poly(arylene sulphide) and the aromatic polymer are present in the composition as a particular filler with particles of mean size from 20 to 50.mu. in a sintered or melted matrix of fluoropolymer(s).

### Claim 6 (depends on 1)

A composition according to claim 1 wherein the sintered matrix is prepared from a PTFE with a mean particle size of 15 to 35.mu..

### Claim 7 (depends on 1)

A composition according to claim 1 wherein the aromatic polymer is a polyimide, polyetherimide, or a poly(arylene etheretherketone), wherein the aromatic moieties of said polymer comprise 1,4-phenylene moieties, or a mixture thereof.

### Claim 8 (depends on 1)

A composition according to claim 1 wherein up to 10 vol. % of the compositions consists of an additive which is carbon; glass fibre or powder; metal powder; ceramic fibres and powders; metal chalcogenide; calcium fluoride; or a siliceous filler, or any combination thereof.

### Claim 9 (depends on 1)

A process for preparing a composition according to claim 1 which comprises
a) dry blending the PTFE and the poly(arylene sulphide); as particulates,
b) heat treating the PTFE and the polyarylene sulphide;
c) adding the aromatic polymer thereto; and
d) heating the blend to a temperature or varying temperature range sufficient to sinter the PTFE to form a matrix of non-melt processable fluoropolymer.

### Claim 10 (depends on 1)

A process for preparing a composition according to claim 1 which comprises:
(a) dry blending the PTFE, the poly(arylene sulphide) and the aromatic polymer as particulates;
(b) heat treating the blend to a temperature within the range of 200.degree. C. to 400.degree. C.; and
(c) heating the blend to a temperature or varying temperature range sufficient to sinter the PTFE to form a matrix of non-melt processable fluoropolymer.