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Method for reducing impurity content in fluorine-containing polymer

A technology for polymers and polymer particles, applied in the field of preparation of high-purity fluoropolymers, can solve the problems of uncontrollable and uniform impurity content, large water consumption, etc. Effect

Active Publication Date: 2010-01-13
SHANGHAI 3F NEW MATERIAL TECH CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the method of washing the polymer particles with water to remove residual initiators and emulsifiers and pressing to remove the washing water mentioned in this U.S. patent can effectively reduce the impurity content, this method has the disadvantage that the impurity content cannot be controlled evenly, and the water consumption bigger problem

Method used

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Examples

Experimental program
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Effect test

preparation example Construction

[0019] The method for preparing the fluoropolymer of the present invention includes the step of preparing the fluoropolymer by emulsion polymerization. In the present invention, the term "fluoropolymer" refers to a homopolymer of vinylidene fluoride, tetrafluoroethylene, chlorotrifluoroethylene monomer, a copolymer of two or more of these monomers, or a copolymer of these monomers Copolymers or terpolymers formed with hexafluoropropylene, ethylene, propylene, trifluoroethylene, fluoroethylene, perfluoroalkyl vinyl ether, or mixtures of the above-mentioned homopolymers and / or copolymers.

[0020] The emulsion polymerization conditions of the present invention are not particularly limited, and may be any emulsion polymerization conditions known in the art that are suitable for specific polymerizable monomers. In one example of the present invention, the emulsion polymerization method includes adding monomers, dispersants or suspending agents, and optional additives such as initi...

Embodiment 1

[0060] Emulsion polymerization of vinylidene fluoride was carried out in a 120L stainless steel reactor. With perfluorooctanoic acid as a dispersant, the addition is 0.1wt%; the paraffin addition is 0.02wt%; percentage); the chain transfer agent is acetone, and its added total amount is 1.5wt%. At the beginning of the reaction, 84kg of deionized water, perfluorooctanoic acid and paraffin were added. After nitrogen gas was introduced for 3 replacements, the temperature and pressure were raised to 130°C and 4.4MPa. At this time, the initiator and chain transfer agent were pumped in at one time. During the reaction process, the pressure and temperature were maintained at 130° C. and 4.4 MPa by adding vinylidene fluoride monomer. After the reaction was completed, the mixture was cooled to 30° C. and discharged into a coagulation tank with a volume of 200 L. At this time, a total of 105 kg of emulsion with a solid content of 20 wt % was obtained.

[0061] After coagulating the em...

Embodiment 2

[0067] 7L of ionized water was added into a 10L stainless steel reaction kettle, and after closing the kettle, it was replaced with nitrogen for 3 times, and 0.05wt% methylcellulose and 0.5% diethyl carbonate were added before the reaction. Turn on the stirring and raise the temperature and pressure to 65°C and 3.0MPa, and then pump 0.2wt% IPP (isopropyl peroxydicarbonate) in at one time. During the reaction, the pressure and temperature are maintained at 65°C and 3.0MPa. After the reaction, an emulsion containing 1.3kg of polyvinylidene fluoride resin was obtained.

[0068] with MgCl 2 After coagulating the emulsion, use three 0.2m 2 The series filter cavity is used for filtering, and the filter cloth is 400 mesh filter cloth. The pumping pressure is 1.0MPa. The water content of the obtained filter cake was 45 wt%. The filter cake is crushed with a high-speed airflow, and crushed into large particles with a particle size of 10-100mm. Add deionized water and the large par...

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Abstract

The invention discloses a preparation method of a fluorine-containing polymer, which comprises the following steps: (a) preparing the fluorine-containing polymer by emulsion or suspension polymerization; (b) pumping the emulsion after condensation into a filter pressing system for carrying out filter pressing and obtaining a filter cake; (c) adopting the gas phase medium crushing method for carrying out pre-crushing on the filter cake, and obtaining polymer particles with maximum particle size of below 200mm; (d) adopting the liquid phase medium crushing method for crushing the polymer particles into particles with the maximum particle size of less than 60mu m; (e) dispersing the obtained polymer particles in water and obtaining a waterborne dispersion; and (g) drying, thereby obtaining a fluorine-containing polymer product. The invention further discloses a method for reducing the content of the impurity in the fluorine-containing polymer.

Description

technical field [0001] The invention relates to a preparation method of high-purity fluorine-containing polymer. In other words, the present invention relates to a method for controlling or reducing the content of impurities in fluoropolymers, by which fluoropolymers having a relatively high purity can be obtained. Background technique [0002] Fluorine-containing polymers include fluorine-containing resins and fluorine-containing rubbers, mainly referring to homopolymers of vinylidene fluoride, tetrafluoroethylene, and chlorotrifluoroethylene, copolymers of two or more of the above-mentioned monomers, these monomers and six Binary or terpolymers of fluoropropylene, ethylene, propylene, trifluoroethylene, fluoroethylene, perfluoroalkyl vinyl ether, or blends of two or more of the above homopolymers or copolymers. The impurity content of fluoropolymers will directly affect the subsequent processing and application. For example, fluororesin with high impurity content will le...

Claims

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Application Information

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IPC IPC(8): C08F6/16C08F6/24C08F14/18
Inventor 吴君毅陆水英张勇陆秋生顾丹
Owner SHANGHAI 3F NEW MATERIAL TECH CO LTD
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