Method for preparing suspension modified polytetrafluoroethylene

A technology of polytetrafluoroethylene and perfluoroalkyl vinyl ether is applied in the field of preparation of suspension-modified polytetrafluoroethylene, which can solve problems such as troublesome handling

Active Publication Date: 2009-10-28
SHANGHAI 3F NEW MATERIAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This kind of light emulsion is very troublesome to treat as waste liquid. It is necessary to condense a small amount of polytetrafluoroethylene contained in the emulsion and get waste. The waste water needs to be treated carefully because it contains perfluorooctanoate

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0018] The invention provides a suspension preparation method of modified polytetrafluoroethylene, which comprises adding all or part of perfluoroalkyl vinyl ether and / or perfluorodioxane into a vacuumized reaction vessel filled with water Pentene comonomer step.

[0019] The present invention uses water as the reaction medium for suspension polymerization. In the method of the present invention, water is first injected into the reaction vessel. The amount of water added is not particularly limited, and it can be a conventional amount used in the art, for example, it can account for 1 / 3 to 2 / 3 of the volume of the reaction vessel. In one example of the present invention, the volume of water added accounts for 3 / 5 of the volume of the reaction vessel.

[0020] To prevent oxygen from interfering with the polymerization reaction, the reaction vessel containing water needs to be purged with an inert gas prior to the reaction. The step of purging the reaction vessel with an iner...

Embodiment 1

[0046] Inject 30 liters of deionized water into the 50-liter reactor, use high-purity nitrogen to repeatedly replace the air in the reactor for at least 3 times, then check the oxygen content in the reactor until the oxygen content is lower than 30ppm, and heat the reactor to At 20°C, vacuum inhale 19 grams of perfluoropropyl vinyl ether, add a redox initiation system composed of potassium persulfate and sodium sulfite, raise the pressure of the tetrafluoroethylene monomer in the kettle to 0.8 MPa, and start stirring to start the reaction. During the reaction process, the reaction temperature was kept fluctuating within the range of ±5°C. After the reaction is finished, unreacted tetrafluoroethylene monomer is recovered, and the pressure inside the kettle is released to obtain fibrous particles. The polymerized product was washed 3 times with deionized water. Then the washed polymer is dried in an oven at 150° C. for 24 hours, and crushed into particles with a particle size o...

Embodiment 2

[0048] Inject 30 liters of deionized water into the 50-liter reactor, use high-purity nitrogen to repeatedly replace the air in the reactor for at least 3 times, then check the oxygen content in the reactor until the oxygen content is lower than 30ppm, and heat the reactor to At 30°C, vacuum inhale 19 grams of perfluoropropyl vinyl ether, add a redox initiation system consisting of potassium persulfate and sodium sulfite, raise the pressure of the tetrafluoroethylene monomer in the kettle to 1.2 MPa, and start stirring to start the reaction. During the reaction process, the reaction temperature was kept fluctuating within the range of ±5°C. After the reaction is finished, unreacted tetrafluoroethylene monomer is recovered, and the pressure inside the kettle is released to obtain fibrous particles. The polymerized product was washed 3 times with deionized water. Then the washed polymer is dried in an oven at 150° C. for 24 hours, and crushed into particles with a particle size...

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Abstract

A method for preparing suspension-modified polytetrafluoroethylene by adding a second comonomer is disclosed. The second comonomer used in the method is perfluoropropyl vinyl ether, and the initiator can be alkali metal or alkaline earth metal persulfate, or a redox initiation system. According to the different initiating systems used, the reaction temperature varies between 5°C and 90°C. The reaction pressure is between 0.5 and 2.0 MPa. Among them, the addition of perfluoropropyl vinyl ether adopts the method of vacuum suction, which avoids the use of perfluorooctanoate.

Description

technical field [0001] The invention relates to a preparation method of suspension modified polytetrafluoroethylene. technical background [0002] Since Dr. Roy Plunkett of DuPont in the United States accidentally obtained polytetrafluoroethylene in 1938, polytetrafluoroethylene has unparalleled chemical resistance, excellent electrical insulation properties, low dielectric constant, extremely low coefficient of friction and the ability to The characteristics of long-term use in the temperature range of -180 ~ 260 ° C have become a pearl in the field of polymer materials. [0003] There are two main preparation methods for polytetrafluoroethylene (PTFE): emulsion polymerization and suspension polymerization. The products prepared by the two methods have different properties, processing methods and application fields. [0004] The particles obtained by emulsion polymerization are easy to form fibers, and the paste extrusion process is mainly used. Products include various ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F114/26C08F2/18
Inventor 粟小理纪云桑佩培侯结民葛丹峰
Owner SHANGHAI 3F NEW MATERIAL TECH CO LTD
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