EP0150953A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Extrusion finishing of perfluorinated copolymers
Assignee: EIDP Inc
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Filing: 1985-01-15
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Granted: —
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Expires: 2005-01-15
Abstract
Abstract Unstable backbone links in melt-processible tetrafluoroethylene copolymers can be reduced by subjecting the copolymer to high shear under specified pressure and temperature conditions in a chamber such as a twin-screw extruder.
Inventors
- 👤 Richard Alan Morgan
- 👤 William Henry Sloan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 09:33
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/50; B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/395; B29C48/40; B29C48/92; B29C2948/00; B29C2948/92; B29C2948/92504; B29C2948/92514; B29C2948/92704; B29C48/022; B29C48/78; B29C48/80; B29C48/802; C08F2810/00; C08F2810/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
125 words
A process for preparing a thermally stable copolymer which comprises a) subjecting in a chamber a raw melt-processible copolymer of 80-99% by weight units of tetrafluoroethylene and complementally 20-1% by weight units of at least one ethylenically unsaturated copolymerizablecomonomer, which copolymer has a backbone volatiles index greater than 15 and a melt viscosity between 10 2 and 10 6 P a.s, to an absolute pressure of less than 10 5 Pa at a temperature of between 220°C and 450°C while moving the copolymer through the chamber and subjecting the copolymer to a shear rate between 500 and 7000 reciprocal seconds for a time sufficient to reduce the backbone volatiles index of the copolymer to less than 15; and b) removing the copolymer from the chamber.
Claim 2
Dependent Claim
125 words
A process for preparing a thermally stable copolymer which comprises a) subjecting in a chamber a raw melt-processible copolymer of 80-99% by weight units of tetrafluoroethylene and complementally 20-1% by weight units of at least one ethylenically unsaturated copolymerizablecomonomer, which copolymer has a backbone volatiles index greater than 15 and a melt viscosity between 10 2 and 10 6 P a.s, to an absolute pressure of less than 10 5 Pa at a temperature of between 220°C and 450°C while moving the copolymer through the chamber and subjecting the copolymer to a shear rate between 500 and 7000 reciprocal seconds for a time sufficient to reduce the backbone volatiles index of the copolymer to less than 15; and b) removing the copolymer from the chamber.
Claim 3
Dependent Claim
18 words
A process according to claim 1 wherein the chamber is a twin screw extruder that contains kneading blocks.
Claim 4
Dependent Claim
18 words
A process according to claim 1 or 2 wherein the copolymer is a copolymer of tetrafluoroethylene and hexafluoropropylene.
Claim 5
Dependent Claim
24 words
A process according to claim 1, 2 or 3 wherein after step b), the copolymer is contacted with fluorine gas while agitating the copolymer.
Claim 6
Dependent Claim
28 words
A process according to any one of the preceding claims wherein water is added to the chamber in an amount sufficient to remove all acid fluoride end groups.
Claim 7
Dependent Claim
35 words
A process according to any one of the preceding claims wherein the copolymer is contacted with nitrogen to remove essentially all absorbed and adsorped oxygen from the copolymer immediately prior to carrying out step a).
Claim 8
Dependent Claim
22 words
Shaped articles melt fabricated from a thermally stable copolymer prepared by a process as claimed in any one of the preceding claims.
References Cited (Backward Citations)
No citation records indexed.
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