Condensation washing method for fluorinated ethylene-propylene resin

A technology of polyperfluoroethylene propylene and washing method, which is applied in the field of post-processing of polymer emulsions, can solve the problems of small particle size and low bulk density of polyperfluoroethylene propylene powder, and achieves high bulk density, large particle size, Easy to use effect

Active Publication Date: 2012-05-09
ZHONGHAO CHENGUANG RES INST OF CHEMICALINDUSTRY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] In order to overcome the technical defects of small particle size and low bulk density

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0031] The preparation process of polyperfluoroethylene propylene resin emulsion is as follows:

[0032] Add 250-300L deionized water and 150-500g perfluorooctanoic acid sodium dispersant into a 500L high-pressure reactor, fill it with nitrogen to test the pressure without leaking, and add a certain amount of initial monomer (by weight TFE:HFP) from the initial tank after the oxygen content is qualified. =20~50:50~80), and heating up, when reaching reaction temperature 70~120 ℃ and pressure 2~4.5MPa, add initiator ammonium persulfate (APS) and potassium persulfate (KPS) mixture with metering pump 150 ~ 200g (weight ratio APS: KPS = 1: 1), start the reaction, and use a membrane press to add additional monomers (by weight TFE: HFP = 95 ~ 70: 5 ~ 30) into the autoclave to maintain the reaction pressure No change, when the amount of added monomer reaches the specified value, stop the reaction.

[0033] The solid content of the obtained polymeric emulsion is 25-30%, the specific g...

Embodiment 1

[0035] The polyperfluoroethylene propylene emulsion has a solid content of 28% and a specific gravity of 1.18.

[0036]Put 500ml of polyperfluoroethylene propylene emulsion at 80°C for 8 hours, add a certain amount of hot deionized water to make the specific gravity of the emulsion 1.15, and control the temperature of the diluted emulsion at 60±2°C. Start stirring at 800rpm, stir for 2 minutes, add 20ml of 10% (wt) nitric acid solution and continue stirring for 15 minutes, add 135ml of trichlorotrifluoroethane (F113), and stop stirring for 5 minutes to release water. Add 500ml of 80°C water, adjust the stirring speed to 450rpm, wash for 4-5min, and wash 3 times, and measure the conductivity of the water after washing to be less than 5μs / cm. The washed resin was dried in a vacuum oven at 160° C. for 5 hours.

[0037] Its particle size was determined to be 20 μm, and its bulk density was 423 g / l.

Embodiment 2

[0039] The polyperfluoroethylene propylene emulsion has a solid content of 26% and a specific gravity of 1.19.

[0040] Put 500ml of polyperfluoroethylene propylene emulsion at 80°C for 8 hours, add a certain amount of hot deionized water to make the specific gravity of the emulsion 1.15, and control the temperature of the diluted emulsion at 60±2°C, start stirring at 800rpm After stirring for 2 minutes, add 15ml of 25% (wt) ammonium bicarbonate aqueous solution, continue to stir for 15min, add 135ml of F113, stop after stirring for 5min, and emit water. Add 500ml of 80°C water, adjust the stirring speed to 450rpm, wash for 4-5min, and wash 3 times, and measure the conductivity of the water after washing to be less than 5μs / cm. The washed resin was dried in a vacuum oven at 160° C. for 5 hours.

[0041] Its particle size was determined to be 18 μm, and its bulk density was 399 g / l.

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Abstract

The invention relates to a condensation washing method for fluorinated ethylene-propylene resin. An emulsion polymerization method is adopted for preparing luorinated ethylene-propylene resin polymerization emulsion, then, the fluorinated ethylene-propylene resin is obtained through still standing, dilution, stirring condensation and washing, and a chemical condensation mode can also be used as an auxiliary mode in the stirring condensation process. The mechanical condensation and the chemical condensation are combined in the condensation washing method provided by the invention, the condensation effect is excellent and is obviously superior to that of the traditional condensation method, the obtained fluorinated ethylene-propylene resin has large grain diameter and high volume density, fluorinated ethylene propylene (FEP) plastics can be favorably and further processed, and in addition, the method has the advantages that the operation is simple and convenient, the condition is mild, and the method is suitable for industrial large-scale application.

Description

technical field [0001] The invention relates to the post-treatment field of polymer emulsions, in particular to a coagulation and washing method of large particle diameter polyperfluoroethylene propylene resin. Background technique [0002] Polyfluoroethylene propylene (FEP) is a polymer obtained by copolymerization of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP) in a certain ratio. It can be obtained from the structural formula of FEP that it is on the helical main chain There is trifluoromethyl, which brings about the disorder of crystallization, and the degree of crystallinity is 40% to 50%, which is obviously much lower than that of PTFE products, and its melt viscosity is only one hundred percent of that of PTFE resin. one-third. It is the earliest determined variety in the series of melt-processable fluororesin products, and its working temperature range is -200~200℃. [0003] FEP is a thermoplastic resin with good processability, excellent high and low te...

Claims

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Application Information

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IPC IPC(8): C08F214/26C08F214/28C08F6/22
Inventor 兰军张建新李斌余金龙赵少春高家勇王先荣白鲸
Owner ZHONGHAO CHENGUANG RES INST OF CHEMICALINDUSTRY CO LTD
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