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Method for preparing polytetrafluoroethylene ultra-fine powder from polytetrafluoroethylene emulsion

A technology of polytetrafluoroethylene and ultrafine powder, which is applied in the field of preparation of fluoropolymer micropowder, can solve the problems of difficult PTFE powder separation, poor working environment, high equipment requirements, etc., and achieves the expansion of product use and high production efficiency , The effect of reducing the discharge of three wastes

Active Publication Date: 2013-07-10
JUHUA GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this process, concentrated hydrochloric acid is added, which is highly corrosive, requires high equipment, and the working environment for employees is poor. A large amount of acid liquid is produced in the waste liquid, which requires further treatment, and the process is complicated.
In addition, because the PTFE powder condensed from the emulsion has very fine particles, and there is a certain concentration of ammonium perfluorooctanoate emulsifier in the system, the system is relatively stable, and it is difficult to separate the PTFE powder from water, which brings trouble to washing

Method used

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  • Method for preparing polytetrafluoroethylene ultra-fine powder from polytetrafluoroethylene emulsion
  • Method for preparing polytetrafluoroethylene ultra-fine powder from polytetrafluoroethylene emulsion

Examples

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Embodiment 1

[0039] Add 60 LPTFE emulsion into a 110L coagulation kettle, raise the temperature of the emulsion to 60°C through the jacket, and then stir at a stirring speed of 500r / min until the emulsion is broken to obtain flocs. Then the demulsified flocs are discharged into a centrifuge device equipped with a 700-mesh filter bag for the first centrifugation to remove part of the water. After centrifuging for 10 minutes, stop the centrifugation, add 36 L of water to the centrifuged material, and continue stirring at a stirring speed of 500 r / min. After 10 minutes, PTFE is separated from the water in the form of fine powder. Stirring was stopped, and the second centrifugation was performed for 20 min to remove most of the water. After adding 54L of water again in the centrifuge, continue stirring at a stirring speed of 300r / min, and stop stirring after 30min. Carry out the centrifugation for the third time, stop centrifugation after 40min, obtain the PTFE wet material containing 10% moi...

Embodiment 2

[0041] Add 70 LPTFE emulsion into a 110L coagulation kettle, raise the temperature of the emulsion to 90°C through the jacket, and then stir at a stirring speed of 800r / min until the emulsion is broken to obtain flocs. Then the floc after demulsification is discharged into the centrifuge device equipped with 400 mesh filter bags, and the first centrifugation is carried out to remove part of the water. After centrifugation for 15 minutes, stop the centrifugation, add 49 L of water to the centrifuged material, and continue stirring at a stirring speed of 300 r / min. After 15 minutes, PTFE is separated from the water in the form of fine powder. Stirring was stopped, and the second centrifugation was performed for 10 minutes to remove most of the water. After adding 48L of water again in the centrifuge, continue to stir, the stirring speed is 100r / min, stop stirring after 20min, carry out the third centrifugation, stop centrifugation after 30min, obtain the PTFE wet material contai...

Embodiment 3

[0043] Add 50 LPTFE emulsion into a 110L coagulation tank, and then stir at a stirring speed of 300r / min, raise the temperature of the emulsion to 50°C through the jacket, stir until the emulsion is broken, and obtain flocs. Then the demulsified flocs are discharged into a centrifuge device equipped with a 300-mesh filter bag for the first centrifugation to remove part of the water. After centrifuging for 30 minutes, stop the centrifugation, add 40 L of water to the centrifuged material, and continue stirring at a stirring speed of 800 r / min. After 12 minutes, PTFE is separated from the water in the form of fine powder. Stirring was stopped and a second centrifugation was performed for 25 minutes to remove most of the water. After adding 42L of water again in the centrifuge, continue to stir, the stirring speed is 200r / min, stop stirring after 5min, carry out the centrifugation for the third time, stop centrifuging after 20min, obtain the PTFE wet material containing 15% moist...

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Abstract

The invention discloses a method for preparing polytetrafluoroethylene ultra-fine powder from polytetrafluoroethylene emulsion. The method comprises the following steps of (1) agitating the polytetrafluoroethylene emulsion to demulsify at 50-90 DEG C to obtain floccule; (2) centrifuging the floccule obtained from step (1) for the first time to remove part of water; (3) agitating for the second time after adding water to the firstly centrifuged material for the first time; (4) centrifuging the secondly agitated material for the second time; (5) agitating for the third time after supplying water to the secondly agitated material for the second time; (6) centrifuging the thirdly agitated material for the third time; and (7) drying the thirdly centrifuged material to obtain the polytetrafluoroethylene ultra-fine powder. The method has the advantages of high production efficiency, low energy consumption, good safety and environment-friendly property, and good product quality.

Description

technical field [0001] The invention relates to a preparation method of fluorine-containing polymer micropowder, in particular to a method for preparing polytetrafluoroethylene superfine powder from polytetrafluoroethylene emulsion. Background technique [0002] The molecular weight of polytetrafluoroethylene (PTFE) ultrafine powder is less than 200,000, which is one percent of the molecular weight of ordinary PTFE. Usually prepared by emulsion telomerization and radiation cracking. The direct raw material of radiation cracking to prepare superfine powder technology is solid-state dry PTFE. This technology is relatively mature in China, and most superfine powders on the market are radiation products. However, radiation cracking technology introduces more unstable end groups and low-carbon chain derivatives (generally 13-20 carbons) into the product, which limits the application of this product in high-end industries. Another preparation method of PTFE ultrafine powder is e...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J3/16C08L27/18
Inventor 汪星平桑益孙倍佳余晓斌邵春明张士林兰方青
Owner JUHUA GRP