Patent US3870689A successfully refreshed from Google Patents.
US3870689A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Crystalline copolymers of ethylene and tetrafluoroethylene having high workability characteristics
Assignee: Montedison SpA
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Filing: 1973-08-16
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Granted: 1975-03-11
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Expires: 1993-08-16
Abstract
Abstract Crystalline copolymers of ethylene and tetrafluoroethylene of high thermal stability characteristics in the molten state and high resistance to oxidation under heat, having a contact in tetrafluoroethylene from 53 to 63% in moles, homogeneously distributed along the chain axis and among the chains characterized in that the temperature gap between their ultimate melting temperature and the temperature at which oxidative decomposition of the copolymers begins is at least 80*C. They are prepared by polymerization of monomers mixtures having a content in tetrafluoroethylene greater than 78% in moles. The copolymers can be used as plastic materials and are particularly useful since said temperature gap of at least 80*C permits the processing thereof, and the reprocessing of scraps, to useful manufactured articles, conveniently and economically and by conventional techniques.
Inventors
- 👤 Mario Modena
- 👤 Mario Ragazzini
- 👤 Giancarlo Borsini
- 👤 Marco Valera
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:43
CPC Classifications
C; C08; C08F; C08F214/00; C08F214/18; C08F214/26; C08F214/265; C08F10/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
114 words
A PROCESS FOR PREPARING CRYSTALLINE ETHYLENE/TETRAFLUOROETHYLENE COPOLYMERS CONTAINING FROM 53 TO 63% BY MOLES OF TETRAFLUOROETHYLENE HOMOGENEOUSLY DISTRIBUTED ALONG THE COPOLYMERIC CHAIN AXIS AND AMONG THE CHAINS, HAVING A HIGH DEGREE OF THERMAL STABILITY, AND SHOWING A TEMPERATURE GAP OF AT LEAST 80*C, MEASURED BY DIFFERENTIAL THERMAL ANALYSIS, BETWEEN THEIR ULTIMATE MELTING TEMPERATURE AND THE TEMPERATURE AT WHICH OXIDATIVE DECOMPOSITION OF THE COPOLYMERS BEINGS, SAID PROCESS BEING CHARACTERIZED IN THAT THE STARTING MIXTURE OF ETHYLENE AND TETRAFLUOROETHYLENE WHICH IS COPOLYMERIZED TO OBTAIN THE COPOLYMERS CONTAINS MORE THAN 78% OF TETRAFLUOROETHYLENE BY MOLES AND THE CONCENTRATION OF TETRAFLUOROETHYLENE IN THE MIXTURE OF MONOMERS IS MAINTAINED ABOVE 78% BY MOLES AND ESSENTIALLY DURING THE COPOLYMERIZATION REACTION.
Claim 2
Dependent Claim
114 words
A PROCESS FOR PREPARING CRYSTALLINE ETHYLENE/TETRAFLUOROETHYLENE COPOLYMERS CONTAINING FROM 53 TO 63% BY MOLES OF TETRAFLUOROETHYLENE HOMOGENEOUSLY DISTRIBUTED ALONG THE COPOLYMERIC CHAIN AXIS AND AMONG THE CHAINS, HAVING A HIGH DEGREE OF THERMAL STABILITY, AND SHOWING A TEMPERATURE GAP OF AT LEAST 80*C, MEASURED BY DIFFERENTIAL THERMAL ANALYSIS, BETWEEN THEIR ULTIMATE MELTING TEMPERATURE AND THE TEMPERATURE AT WHICH OXIDATIVE DECOMPOSITION OF THE COPOLYMERS BEINGS, SAID PROCESS BEING CHARACTERIZED IN THAT THE STARTING MIXTURE OF ETHYLENE AND TETRAFLUOROETHYLENE WHICH IS COPOLYMERIZED TO OBTAIN THE COPOLYMERS CONTAINS MORE THAN 78% OF TETRAFLUOROETHYLENE BY MOLES AND THE CONCENTRATION OF TETRAFLUOROETHYLENE IN THE MIXTURE OF MONOMERS IS MAINTAINED ABOVE 78% BY MOLES AND ESSENTIALLY DURING THE COPOLYMERIZATION REACTION.
Claim 3
Dependent Claim
114 words
A process for preparing crystalline ethylene/tetrafluoroethylene copolymers containing from 53 to 63% by moles of tetrafluoroethylene homogeneously distributed along the copolymeric chain axis and among the chains, having a high degree of thermal stability, and showing a temperature gap of at least 80*C, measured by differential thermal analysis, between their ultimate melting temperature and the temperature at which oxidative decomposition of the copolymers begins, said process being characterized in that the starting mixture of ethylene and tetrafluoroethylene which is copolymerized to obtain the copolymers contains more than 78% of tetrafluoroethylene by moles and the concentration of tetrafluoroethylene in the mixture of monomers is maintained above 78% by moles and essentially during the copolymerization reaction.
Claim 4
Dependent Claim
114 words
A process for preparing crystalline ethylene/tetrafluoroethylene copolymers containing from 53 to 63% by moles of tetrafluoroethylene homogeneously distributed along the copolymeric chain axis and among the chains, having a high degree of thermal stability, and showing a temperature gap of at least 80*C, measured by differential thermal analysis, between their ultimate melting temperature and the temperature at which oxidative decomposition of the copolymers begins, said process being characterized in that the starting mixture of ethylene and tetrafluoroethylene which is copolymerized to obtain the copolymers contains more than 78% of tetrafluoroethylene by moles and the concentration of tetrafluoroethylene in the mixture of monomers is maintained above 78% by moles and essentially during the copolymerization reaction.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-10 | 1978-09-09 | 1979-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-10 | 1982-09-09 | 1983-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-10 | 1986-09-09 | 1987-03-11 | $7700.00 | Window Closed / Lapsed |