Claims
- 1. A process for preparing a propylene-tetrafluoroethylene copolymer, comprising; copolymerizing tetrafluoroethylene and propylene in a molar ratio ranging from 95/5 to 40/60 in an aqueous medium containing tertiary butanol ranging from 5 to 30 wt.%, an emulsifier ranging from 0.01 to 10 wt.% and a redox catalyst system of (1) a water soluble persulfate, (2) a water soluble iron salt, (3) a hydroxymethanesulfinate and (4) ethylenediamine-tetraacetic acid or salt thereof at a pH of 8 to 10.5 and at a temperature of 0.degree. to 50.degree. C.
- 2. The process of claim 1, wherein said hydroxymethanesulfinate is an alkali metal salt.
- 3. The process of claim 1, wherein said iron salt is ferrous sulfate, ferric sulfate, ferrous nitrate, ferric nitrate, ferrous chloride, ferric chloride, ammonium ferrous sulfate or ammonium ferric sulfate.
- 4. The process of claim 1, wherein the concentration of redox catalyst in the aqueous medium ranges from 0.001 to 5 wt.%.
- 5. The process of claim 1, wherein the concentration of said persulfate in said aqueous medium ranges from 1 to 50 m mole/liter, the concentration of both the iron salt and ethylenediaminetetraacetic acid or salt thereof ranges from 0.05 to 5 m mole/liter and the concentration of said hydroxymethanesulfinate ranges from 0.5 to 50 m mole/liter.
- 6. The process of claim 1, wherein the pressure during copolymerization is less than 100 kg/cm.sup.2.
- 7. The process of claim 6, wherein said pressure ranges from 5-80 kg/cm.sup.2.
- 8. The process of claim 1, wherein the pH of said reaction medium ranges from 8.5 to 10.5.
- 9. The process of claim 1, wherein the temperature of polymerization ranges from 5.degree.-45.degree. C.
- 10. The process of claim 1, wherein said emulsifier is a polyfluoroaliphatic carboxylic acid, a perfluoroaliphatic carboxylic acid, polyfluorochloroaliphatic carboxylic acid, a water-soluble salt of any one of said carboxy acids, a perfluorochloroaliphatic carboxy acid, a phosphate or sulfate of a polyfluoroalcohol, a sulfate of a higher fatty alcohol or a water-soluble salt of an aromatic sulfonic acid.
- 11. The process of claim 10, wherein the concentration of said emulsifier in the reaction medium ranges from 0.1 to 5 wt%.
- 12. The process of claim 1, wherein said copolymerization medium further comprises at least one of a pH regulator, a buffering agent and a chain transfer agent.
Parent Case Info
This application is a continuation-in-part of application Ser. No. 185,744 filed Sept. 10, 1980, now abandoned.
US Referenced Citations (4)
Foreign Referenced Citations (1)
Number |
Date |
Country |
553813 |
Mar 1958 |
CAX |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
185744 |
Sep 1980 |
|