Patent US4942553A successfully refreshed from Google Patents.
Patent US3755235A successfully refreshed from Google Patents.
US3755235A
Expired / Lapsed
US
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Polytetrafluoroethylene emulsions having improved properties
Assignee: Montedison SpA
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Filing: 1971-01-05
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Granted: 1973-08-28
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Expires: 1991-01-05
Abstract
Abstract Stabilized polytetrafluoroethylene emulsions particularly suitable for protective coating applications are produced by adding, to emulsions obtained from conventional emulsion polymerization of tetrafluoroethylene, a perfluoroketoether compound. The resulting emulsions are much more resistant to coagulation than are untreated emulsions when subjected to agitation or contacted with ionic materials such as acids and salts. More desirable coatings than heretofore possible, that are less subject to yellow discoloration occurring in conventional coatings and capable of being cast at greater thickness (of up to about 40 microns) without carcking, are obtained therewith. Concentrated polytetrafluoroethylene emulsions are produced by adding ionic material to the foregoing stabilized emulsions.
Inventors
- 👤 D Sianesi
- 👤 G Bernardi
- 👤 G Veroli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:30
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/02; C08J3/03; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
25 words
The aqueous polytetrafluoroethylene emulsion of claim 1, which contains the perfluoroketoether in an amount between about 0.001 and 0.1 mole per 100 grams of polymer.
Claim 2
Dependent Claim
24 words
The aqueous polytetrafluoroethylene emulsion of claim 2, wherein the amount of perfluoroketoether is between about 0.005 and 0.060 moles per 100 grams of polymer.
Claim 3
Dependent Claim
22 words
The aqueous polytetrafluoroethylene emulsion of claim 1, which has a polytetrafluoroethylene concentration in excess of 20 percent by weight of said emulsion.
Claim 4
Dependent Claim
24 words
The aqueous polytetrafluoroethylene emulsion of claim 1, which has a polytetrafluoroethylene concentration of from about 10 to 18 percent by weight of said emulsion.
Claim 5
Dependent Claim
22 words
The aqueous polytetrafluoroethylene emulsion of claim 3, which has a polytetrafluoroethylene concentration in excess of 20 percent by weight of said emulsion.
Claim 6
Dependent Claim
52 words
A process for the preparation of a concentrated aqueous polytetrafluoroethylene emulsion which comprises first adding to a dilute aqueous emulsion consisting essentially of solid polytetrafluoroethylene, water and the surfactant employed in the emulsion polymerization phase, at least about 0.001 mole per 100 grams of said polytetrafluoroethylene of a perfluoroketoether having the formula:
Claim 7
Dependent Claim
21 words
The process of claim 7 wherein said perfluoroketoether is dispersed in water prior to the addition thereof to said dilute emulsion.
Claim 8
Dependent Claim
22 words
The process of claim 7 wherein said ionic agent is dissolved in water prior to the addition thereof to said dilute emulsion.
Claim 9
Dependent Claim
29 words
The process of claim 7 wherein the amount of said perfluoroketoether added to said emulsion is from about 0.005 to 0.030 moles of perfluoroketoether per 100 grams of polymer.
Claim 10
Dependent Claim
30 words
The process of claim 7 wherein the amount of said ionic agent added to said emulsion is from about 0.01 to 6 moles of ionic agent per liter of emulsion.
Claim 11
Dependent Claim
27 words
The process of claim 7 wherein the concentration of polytetrafluoroethylene in said dilute aqueous emulsion is from about 10 to about 18% by weight of said emulsion.
Claim 12
Dependent Claim
18 words
The process of claim 12 wherein said dilute emulsion is obtained directly from the emulsion polymerization of tetrafluoroethylene.
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) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |