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Method for removing perfluoro caprylic acid from dispersing liquid of perfluoro polymer by using two-section method

A perfluoropolymer and perfluorooctanoic acid technology, which is applied in the field of perfluorooctanoic acid removal in perfluoropolymer dispersions, can solve the problems of difficult extraction and washing, large adsorption capacity, and weak removal ability

Active Publication Date: 2010-03-03
SHANDONG DONGYUE POLYMER MATERIAL
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0006] Anion exchange resins are generally divided into strongly basic anion exchange resins and weakly basic anion exchange resins, which are characterized by: strong basic anion exchange resins have strong removal ability, can achieve complete removal effect, and have a high pH value The liquid has little effect on its removal ability; but its exchange capacity is small, and it is difficult to extract after saturation, and the amount of extraction liquid is large
Weak base anion exchange resin has a weak removal ability, and there are still some residual ions in the liquid after adsorption, and the removal effect on liquids with relatively high pH is poor; small amount
[0007] Prior art is that perfluoropolymer (especially polytetrafluoroethylene) dispersion liquid only utilizes weakly basic ion exchange resin to carry out ion adsorption, and the initial perfluorooctanoic acid (PFOA) content of the dispersion liquid after this method removes is about 10- 30ppm, after long-term exchange, the exchange capacity of the weakly basic ion exchange resin decreases, and the content of perfluorooctanoic acid (PFOA) inevitably increases, even reaching higher than 50ppm

Method used

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Examples

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specific Embodiment approach

[0019] The following examples are further illustrations of the present invention, but the present invention is not limited thereto.

[0020] If there is no special instruction, the size of the ion exchange column used in the examples is The height is 2000mm, and it is equipped with corresponding thermometers, pH meters, eluent circulation pumps, eluent storage tanks, pressure gauges, flow meters and corresponding pipelines. All types of ion exchange resins used are Zibo Dongda Chemical Co., Ltd. products, ion exchange resins with a D prefix in the model number are macroporous ion exchange resins, and those without a D prefix are gel type ion exchange resins. The ion exchange resin is all activated according to the prior art before being filled into the ion exchange column. The content of perfluorooctanoic acid in the raw material perfluoropolymer dispersion used in the examples is 1000-3500ppm.

[0021] The used ion exchange resin is regenerated as follows:

[0022] After ...

Embodiment 1

[0023] Embodiment 1: adopt D301 type anion exchange resin and D201 type anion exchange resin

[0024] Raw materials: 2000 kg of polytetrafluoroethylene dispersion (perfluorooctanoic acid content is 2500ppm).

[0025] Fill the D301-type and D201-type ion-exchange resins into two ion-exchange columns respectively, and the filling height is 2 / 3 of the ion-exchange column. Make the polytetrafluoroethylene dispersion pass through the D301 resin ion exchange column and the D201 resin ion exchange column successively at a flow rate of 3 times the resin volume / hour. The temperature of the polytetrafluoroethylene dispersion is lower than 50°C before entering the ion exchange column, and the pH value 9. After the first stage of adsorption with D301 weakly basic anion exchange resin, the concentration of perfluorooctanoic acid in it is 15ppm, and then after the second stage of adsorption with D201 strong basic anion exchange resin, the perfluorooctanoic acid (PFOA) in the polytetrafluor...

Embodiment 2

[0026] Embodiment 2: adopt D301 type anion exchange resin and 201 * 7 type anion exchange resin

[0027] Raw materials: 2000 kg of polytetrafluoroethylene dispersion (perfluorooctanoic acid content is 3000ppm).

[0028]Two ion exchange resins of type D301 and type 201×7 are respectively filled into two ion exchange columns, and the filling height is 1 / 3 of the ion exchange column. Make the raw material polytetrafluoroethylene dispersion pass through the D301 resin ion exchange column and the D201×7 resin ion exchange column successively at a flow rate of 2 times the resin volume / hour, and the temperature of the polytetrafluoroethylene dispersion before entering the ion exchange column is lower than 50°C , pH 8.5. After the first stage of adsorption with D301 weakly basic anion exchange resin, the concentration of perfluorooctanoic acid in it is 14ppm, and then the second stage of adsorption is carried out through 201×7 strong basic ion exchange resin, and the dispersion liqui...

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Abstract

The invention relates to a method for removing a perfluoro caprylic acid from a dispersing liquid of perfluoro polymer by using a two-section method, comprising the steps: carrying out a first sectionof absorption on the dispersing liquid of the perfluoro polymer by using anion exchange resins with alkalescence; and carrying out a second section of absorption through ion exchange resins with strong alkaline to completely remove the caprylic acid from the dispersing liquid of the perfluoro polymer. The perfluoro caprylic acid of the produced dispersing liquid of the perfluoro polymer can not be detected according to a certificate organization, and the produced dispersing liquid completely conforms to various indexes, therefore, the method is suitable for scale and continuous production.

Description

technical field [0001] The invention belongs to the technical field of fluorine-containing polymer materials, and in particular relates to a method for removing perfluorooctanoic acid after a fluorine-containing dispersion, especially a method for removing perfluorooctanoic acid in a perfluoropolymer dispersion. technical background [0002] Perfluorooctanoic acid (PFOA) plays a very important role as an auxiliary agent in the production of perfluoropolymers (especially polytetrafluoroethylene), but its potential carcinogenicity makes the use of perfluorooctanoic acid and products containing perfluorooctanoic acid subject to relatively large limit. The EU Directive on Restricting the Sales and Use of Perfluorooctane Sulfonate (PFOS Directive) came into effect on June 27, 2008. According to the directives: 1) If the product composition formula contains PFOS greater than 0.005% (50ppm) of the total weight, it shall not be sold on the EU market. 2) The part containing PFOS in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F14/26C08F214/26C08F214/28C08F6/00
Inventor 周冰韩淑丽夏俊孟章富
Owner SHANDONG DONGYUE POLYMER MATERIAL
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