Production method of low molecular weight tetrafluoro ethylene resin

A polytetrafluoroethylene, production method technology, applied in the field of warm polymerization, can solve problems such as high viscosity, large dispersion, and large environmental pollution, and achieve the effect of fine and uniform particles and good dispersion

Active Publication Date: 2007-04-18
ZHONGHAO CHENGUANG RES INST OF CHEMICALINDUSTRY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The defect of this process is the intermittent operation mode of the follow-up process, which not only consumes energy but also takes time; when coagulating, concentrated hydrochloric acid is added, the operating environment is poor, the corrosion is strong, and a large amount of low-concentration hydrochloric acid waste liquid is produced, which is difficult to handle, and the polymerization liquid coagulates Equipment material requirements are strict
[0008] It should be noted that in the 16th page of the fourth issue of "Organic Fluorine Industry" in 2003, it is disclosed that foreign countries use dichloromethane and monochloromethane as chain transfer agents in the preparation of low-molecular-weight polytetrafluoroethylene resins. It clearly states that Because the reactivity of monochloromethane and dichloromethane is larger than that of difluorochloromethane, they will remain in the emulsion, which will bring troubles to the recovery and coagulation of TFE after polymerization. If the polymerization recovery monomer process does not take effective According to the technical measures, the chain

Method used

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  • Production method of low molecular weight tetrafluoro ethylene resin
  • Production method of low molecular weight tetrafluoro ethylene resin

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Experimental program
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Embodiment 1

[0020]Embodiment 1: 1. Polymerization: Select 1000L stainless steel jacketed reactor, which has the advantages of rapid temperature rise, heat transfer and excellent effect. After washing, add deionized water, ammonium persulfate, and ammonium perfluorooctanoate solution according to the formula, and seal the reactor body, evacuate, replace with inert gas, analyze the oxygen content in the kettle, if the oxygen content is less than 30ppm, it is qualified, fill with tetrafluoroethylene gas phase monomer and methylene chloride liquid, at this time, the pressure in the kettle is 0.5-0.8MPa, and the temperature in the kettle rises to 70 At this time, the polymerization reaction proceeds, and the pressure in the kettle drops. The whole polymerization process is controlled at a stable pressure of 0.8±0.05MPa, and the reaction temperature is controlled at 100-75℃. When the pressure in the kettle drops, add tetrafluoroethylene gas phase single body, when the reaction rate drops in the ...

Embodiment 2

[0025] Embodiment 2: 1. Polymerization: select 1000L stainless steel jacketed reactor, rapid temperature rise, heat transfer and excellent effect of the reactor, after washing, add deionized water, ammonium persulfate, ammonium perfluorooctanoate solution according to the formula, and seal the reactor body, evacuate, replace with inert gas, analyze the oxygen content, the oxygen content is less than 30ppm is qualified, fill the tetrafluoroethylene gas phase and dichloromethane liquid, at this time the pressure in the kettle is 0.1 ~ 1.0MPa, the temperature in the kettle rises to 70 ℃, at this time The polymerization reaction proceeds, the pressure in the kettle drops, and the whole polymerization process is controlled at a stable pressure of 0.8±0.05MPa, and the reaction temperature is controlled at 100-75°C. When the pressure in the kettle drops, tetrafluoroethylene gas phase monomer is added. When the reaction rate drops, ammonium persulfate is allowed to be added. The whole...

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Abstract

This invention discloses a preparation of low molecular weight teflon, it adopts emulsion polymerization method, utilizing deionized water as polymerization medium, utilizing Perfluorooctanoic acid as dispering agent, utilizing dichlormethane as chain transfer agent, tetafluoroethylene metamer is polymerized by utilizing persulfate as initiator. Low molecular weight Teflon is gained by agglomerating and continuously drying polymerization solution, this invention can prepare low molecular weight PTFE resin which is water-galact typus and excellent constance, it is completely suitable for follow-up manipulation and continuous operation. it can be extently enlarged, spray drying technology is energy saving and save time, directly obtained particle is thin and uniform and spherical, molecular weight distributes between 4-8*103, it has a good dispersibility for other composition, it can completely be suitable to prepare composite of low molecular weight PTFE resin whose specification is that every composition is easy to be mixed uniformly and permanent.

Description

technical field [0001] The invention relates to a method for producing low-molecular-weight polytetrafluoroethylene resin, more precisely, it relates to a method for preparing low-molecular-weight polytetrafluoroethylene resin by isothermally polymerizing under water medium conditions with dichloromethane as a chain transfer agent. Background technique [0002] Polytetrafluoroethylene resin (PTFE) is known as the "King of Plastics" by the synthetic material industry due to its good mechanical properties, electrical properties, chemical resistance, weather resistance, non-stickiness and lubricity. The molecular weight of low molecular weight polytetrafluoroethylene (also known as PTFE micropowder, commonly known as wax powder) is generally one percent of that of commonly used high molecular weight PTFE, generally 3000-10000, the average particle size is 1-20μm, and the melting point is 315-320℃ , because it has the same chemical structure as high mol...

Claims

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Application Information

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IPC IPC(8): C08F114/26C08F2/22C08F2/38C08F2/00
Inventor 胡显权张建新何炯姚权卫
Owner ZHONGHAO CHENGUANG RES INST OF CHEMICALINDUSTRY CO LTD
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