RU2348649C1 - Method of obtaining perfluorated copolymer containing functional groups - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention claims method of obtaining perfluorated copolymer containing functional groups, involving emulsion copolymerisation of tetrafluoroethylene and perfluoro-2-fluorosulfonylethoxypropylvinyl ether in the presence of radical initiation agent and perfluorocarboxylic acid salt as emulsion stabiliser. Method involves preliminary stage of perfluoro-2-fluorosulfonylethoxypropylvinyl ether emulsification in water medium. Emulsion copolymerisation of tetrafluoroethylene and perfluoro-2-fluorosulfonylethoxypropylvinyl ether is performed at constant tetrafluoroethylene pressure of 0.48-0.52 MPa and stopped when perfluoro-2-fluorosulfonylethoxypropylvinyl ether conversion reaches 49-77%, and preliminary stage of perfluoro-2-fluorosulfonylethoxypropylvinyl ether emulsification in water medium involves rotor-stator type homogenisation agent as disperser, at rotor rotation rate of 8000-12000 rpm, using perfluorocarboxylic acid ammonium salt C_nF_2n+1COONH₄ for emulsion stabilisation, where n=7-9. Emulsification is performed in inert gas medium.

EFFECT: efficient method of obtaining perfluorated copolymer.

6 cl, 5 ex

Description

The invention relates to the production of perfluoropolymers containing functional groups, specifically sulfonyl fluoride groups. Such copolymers are the basis for the manufacture of ion-exchange membranes used in fuel cells, various electrolyzers, etc.

Membranes with the trade name Nafion, based on the cation exchange copolymer obtained by hydrolysis of the perfluorosopolymer tetrafluoroethylene (TFE) - perfluoro-2-fluorosulfonylethoxypropyl vinyl ether (PFEPVE) with an equivalent weight of 1000-1100, are widely known. Membranes based on this copolymer are characterized by high chemical and thermal resistance, high strength and electrochemical properties. The combination of this set of properties allows the use of membranes of this type for the manufacture of fuel cells with a long resource of continuous operation.

A number of methods are known for producing TFE and PFEPVE copolymers during copolymerization in a medium of halogen-containing hydrocarbons, for example, such as trifluorotrichloroethane (freon 113) [US 3528954, C08F 15/06, 09/15/1970; US 3642742, C08F 16/00, 02.15.1972]. The main disadvantage of these methods is the low yield of the copolymer, while the conversion of PFEPVE, as a rule, does not exceed 20-25%. This is due, on the one hand, to the very high viscosity of the reaction medium with an increase in the conversion of monomers and the difficulty of mixing it, which can cause overheating of the reaction mass and the appearance of local inhomogeneities in the resulting copolymer. On the other hand, increasing the conversion of monomers above a certain value makes it impossible to obtain a copolymer with the desired equivalent weight. In other words, the resulting copolymer is compositionally extremely heterogeneous. The low yield of the target product suggests the need for the inclusion in the process of additional stages associated with the regeneration of PFEPVE, and an expensive solvent, which complicates the technology and increases the cost of the resulting copolymer. It should also be noted the environmental hazard of processes in which fluorine and chlorine solvents are used that destroy the ozone layer.

More promising methods for producing perfluoropolymers with functional sulfonyl fluoride groups in an aqueous medium by the mechanism of emulsion polymerization. In processes of this type, there are no problems associated with the high viscosity of the reaction mass, since the product of emulsion copolymerization is latex, a dispersion of polymer particles in water. The absence of an organic solvent improves working conditions, reduces the environmental hazard of the process, makes the process more technological and economical in view of reducing the cost of regeneration of products that have not reacted.

The patent [US 3282875, C08F 28/00, 01/11/1966, Example 17] describes the copolymerization of TFE and PFEPVE in an emulsion stabilized with ammonium perfluorocaprylate in the presence of a radical initiator, ammonium persulfate at 85 ° C and a TFE pressure of 0.34 MPa. The disadvantage of this method is the low conversion of PFEPVE (21%) and non-optimal equivalent mass of the copolymer (2590).

A known method for conducting emulsion copolymerization of TFE and PFEPVE [US 5608022, C08F 2/16, 03/04/1997, example 15], in which ammonium perfluorocaprilate and ammonium persulfate were also used as initiator and stabilizer of the emulsion, respectively, but the process was carried out at 60 ° C and TFE pressure 1.6 MPa. A distinctive feature of this method is the preliminary emulsification of PFEPVE in water in the presence of ammonium perfluorocaprylate on an ABM-4 biomixer manufactured by K. K. Nippon with a mixing speed of 20,000 rpm for 30 minutes. Another distinguishing feature is the use of aliphatic alcohol in the formulation as a chain transfer agent. As a result, a copolymer is formed with an equivalent mass close to optimal (1025) and a melt flow rate of 1.5 g / 10 min at 270 ° C and a load of 2.16 kg, indicating the possibility of processing the copolymer into the membrane by traditional methods, for example, by extrusion. The disadvantages of the method are the process at a fairly high pressure TFE and a very low conversion of PFEPVE (12%). The latter circumstance, the inventors associate with the possibility of changing the equivalent mass of the copolymer with increasing its yield.

The closest in technical essence to the claimed invention is the method described in the patent [Application WO 0052060, C08F 2/18, 08.09.2000, examples 7, 8]. This method also uses the method of preliminary emulsification of PFEPVE in water when using a homogenizer type MicroFluidizer. Emulsion stabilization is carried out using ammonium perfluorooctanoate. Ammonium persulfate or the redox initiating system of ammonium persulfate - sodium sulfite is used as an initiator. The process is carried out depending on the type of initiating system either at 60 ° C or at 35 ° C. TFE pressure varies from 0.34 to 1.38 MPa. Before copolymerization, a 4-liter reactor is subjected to special treatment with an aqueous solution of ammonium persulfate and ammonium perfluorooctanoate (5 g of each component in 2 liters of water) at a temperature of 100 ° C and a stirring speed of 150 rpm. Then the reactor is cooled and the indicated solution is unloaded, after which the prepared emulsion and other components are loaded, degassing, TFE purging are carried out, heated to the required temperature, the required TFE pressure is set, the components of the initiating system are loaded and the process is conducted at a stirring speed of 200 rpm. If the process is carried out using a redox initiating system, then during the copolymerization simultaneously with the addition of TFE, the PFEPVE emulsion is dosed. From the obtained latex, the polymer is isolated by freezing, washed repeatedly with tap and demineralized water, and then dried at 100 ° C in vacuo. The result is a copolymer with an equivalent weight of 934 and a conversion of PFEPVE of 70% upon initiation of copolymerization by a redox initiating system. If only ammonium persulfate is used as the initiator, then the equivalent mass of the copolymer is 1228, and the conversion is 80%.

The disadvantages of the described method are:

1. A very complex technology, requiring the use of expensive and complex equipment (MicroFluidizer, dispensers of liquid components operating under pressure) and special preparation of the polymerization reactor.

2. High consumption of costly perfluorinated surfactants (12-16% of the mass of PFEPVE loaded into the rector).

3. The consequence of claim 2 is the large amount of water required to carry out the process and rinse the resulting copolymer. On average, 225 liters of tap water and 66 liters of demineralized water are consumed per 1 kg of the obtained copolymer, which implies significant costs for wastewater treatment.

4. The resulting copolymer has a low melt flow rate (0.214 g / 10 min at 270 ° C and a load of 1.2 kg), which may complicate its processing by extrusion.

The invention solves the problem of simplifying the technology for producing the TFE-PFEPVE perfluoropolymer using the emulsion copolymerization method, reducing the consumption of perfluorinated surfactant and water in the process of isolating the copolymer from latex (reducing the volume of wastewater), achieving high conversion of PFEPVE while maintaining optimal characteristics of the resulting copolymer (equivalent weight 920- 1075, melt flow rate 13-27 g / 10 min at a temperature of 270 ° C and a load of 2.16 kg or 7-13 g / 10 min at a load of 1.2 kg, proton conductivity of the membrane, made from a copolymer of at least 0.10 S / cm).

The problem is solved due to the fact that the emulsion copolymerization of TFE and PFEPVE is carried out at a constant pressure of TFE 0.48-0.52 MPa, stopping the process during the conversion of PFEPVE 49-77%, and at the stage of preliminary emulsification of PFEPVE in an aqueous medium, a rotor-stator homogenizer is used as a dispersant at a rotor rotation speed of 8000-12000 rpm, applying for the stabilization of the emulsion the ammonium salt of perfluorocarboxylic acid C _n F _{2n + 1} COONH ₄ , where n = 7-9, in an amount of 2.5-3.5% by weight of perfluoro-2-fluorosulfonylethoxypropyl vinyl ether and emulsification about uschestvlyayut in an inert gas atmosphere at a weight ratio of perfluoro-2-ftorsulfoniletoksipropilvinilovy ether / water = 0.141-0.152.

In emulsion copolymerization, the potassium or ammonium persulfate — sodium metabisulfite — with a content of persulfate 0.82–1.53, sodium metabisulfite 0.22–0.94% of the mass of PFEPVE and the mass ratio of ammonium persulfate / sodium metabisulfite = 1.62–3.75, and a = 1.62–3.75, are used as a radical initiator. copolymerization is carried out at a temperature of 35-45 ° C.

The emulsion of PFEPVE in water is produced in the presence of an emulsifier - ammonium salt of perfluorocarboxylic acid, buffer additives (monosubstituted sodium phosphate and disubstituted sodium phosphate) and one of the components of the redox initiating system - potassium or ammonium persulfate. Emulsification on a homogenizer rotor-stator is carried out for 15 minutes Emulsion copolymerization is carried out in a stainless steel reactor with stirring by an anchor mixer at a speed of 200-250 rpm with a reactor volume of 200 cm ³ . The process is carried out for 3-7 hours. The resulting latex is discharged from the reactor and coagulated when the reaction product is acidified with an inorganic acid. The isolated copolymer is washed several times with chloroform to remove unreacted PFEPVE and distilled water in order to wash the emulsifier and inorganic salts. The washed copolymer is dried first in air for 10-20 hours, and then under vacuum at 100 ° C for 5-10 hours.

For the dried copolymer, the equivalent mass and melt flow rate are determined, and then samples are produced from the copolymer by extrusion under pressure, which are subjected to hydrolytic processing in order to transfer -SO ₂ F- groups to acid groups -SO ₂ F. On the resulting In the manner of cation exchange membranes, electrochemical and mechanical characteristics are measured.

The authors of the present invention unexpectedly found that with the selected parameters of the polymerization process, a copolymer is formed that is uniform in chemical composition even at a very high degree of conversion of PFEPVE (see example 5). As you know, a similar effect is impossible when the process is carried out in a solvent.

The invention is illustrated by the following examples.

Example 1

In a glass cup with a capacity of 300 cm ^3, 100 cm ^{3 of} distilled water previously purged with nitrogen was loaded and 0.45 g (2.51% by weight of PFEPVE) ammonium perfluorooctanoate, 0.45 g (2.51% by weight PFEPVE) of disubstituted sodium phosphate, 0.6 g (3.35% by weight) were dissolved PFEPVE) of monosubstituted sodium phosphate and 0.15 g (0.84% by weight of PFEPVE) of potassium persulfate. Then, 17.9 g of PFEPVE is loaded into the resulting solution, a homogenizer working element is introduced, nitrogen flow is generated over the surface of the prepared mixture, and the rotor begins to rotate at a speed of 10,000 rpm. Emulsification is stopped after 15 minutes and the resulting emulsion is left under a stream of nitrogen for 30 minutes to settle the foam.

At the same time, a reactor with a volume of 200 cm ^{3 is} prepared for copolymerization. The reactor is successively evacuated and filled with TFE to a pressure of 0.05 MPa. This operation is carried out three times. The resulting emulsion is loaded into the reactor and a nitrogen purge is performed for 30 minutes. 0.045 g (0.25% by weight of PFEPVE) of sodium metabisulfite dissolved in 20 cm ^{3 of} degassed distilled water is loaded into the reactor, the reactor is closed and TFE is supplied to a pressure of 0.1 MPa. Then the pressure is reduced to atmospheric and TFE is fed again. This operation is carried out three times. After that, the reaction mass is heated to 40 ° C, the working pressure of TFE is established (0.52 MPa) and the process is conducted for 5 hours with constant feeding of TFE. Make-up is produced when TFE pressure is reduced by 0.02 MPa. During the reaction, 15.43 g of TFE is consumed.

After completion of the process, the reaction mass is cooled to room temperature, TFE is blown off, the resulting latex is discharged, and coagulation is carried out by adding 50 ml of concentrated hydrochloric acid. The copolymer released is separated from the liquid phase on a Buchner funnel, washed several times with water, then placed in a glass and washed with vigorous stirring with a mixture (emulsion) of chloroform and water, after which the copolymer is separated from the liquid phase on a Buchner funnel. The described procedures are carried out three times.

A total of 1.6 liters of water or 51 liters per 1 kg of copolymer are used to flush the copolymer.

The washed copolymer is dried in air at room temperature for 16 hours, and then under vacuum at 100 ° C.

The copolymer yield was 31.3 g. The melt flow rate (MFR) determined on the IIRT-M plastometer at 270 ° C with a load of 2.16 kg is 27 g / 10 min or 13 g / 10 min at a load of 1.2 kg.

For testing, films are made from the obtained copolymer by extrusion.

A portion of the copolymer for pressing (G) is calculated by the formula:

G-V · ρ · K,

where V is the volume of the pressed film, cm ³ ,

ρ is the density of the copolymer equal to 2.1 g / cm ³

K is a correction factor of 1.1, taking into account the excess copolymer.

A portion of the copolymer in the form of a powder is poured onto a X18H10T stainless steel plate with a 100 μm thick aluminum foil gasket, the powder is leveled according to the shape limiter with dimensions 70 × 130 × 0.1 mm, closed with an aluminum foil gasket and a massive stainless steel plate. The form with the copolymer is maintained at a pressing temperature (230-250 ° C) for 15 minutes, the specific pressure is set at 20.0-23.0 MPa and the mold is kept under pressure for 5 minutes. After that, the mold with the copolymer is cooled under pressure, the pressure is released, the limiter with the film is removed from the mold, cooled to room temperature and the film is pressed out.

A film is obtained with a thickness of 100 μm with a smooth smooth surface without melt, inclusions, shells and other visible defects with dimensions of 70 × 130 × 0.1 mm with a thickness of not more than 10%.

The study of the IR spectrum of copolymer films shows the absence of absorption in the regions of 1840 and 1055 cm ⁻¹ , which indicates the complete removal of unreacted PFEPVE from the copolymer and the absence of sulfonic acid groups in its structure. The latter fact indicates that hydrolysis of sulfonyl fluoride groups does not occur in the process of emulsion copolymerization and processing of the copolymer.

The equivalent mass of the copolymer (EM) is determined by IR Fourier transform spectroscopy on pressed films in the sulfonyl fluoride form. The integrated intensities A of the bands of 2704 cm ^-1 (combined vibration frequency of the -SO ₂ F group) and 2363 cm ^-1 (overtone of the vibrations of the -CF ₂ group) are measured.

EM is calculated by the formula:

EM = 446 [1 + k (A (2363) -A (2704)) / A (2704)],

where the coefficient k is determined from reference samples with a known exchange capacity determined by titration.

The EM value measured by the indicated procedure is 1010.

Based on the data on the EM value, the yield of the copolymer (W) and the amount of PFEPVE loaded into the reaction mixture (W ₁ ), the conversion of PFEPVE is calculated by the formula

where 446 is the molecular weight of PFEPVE.

In the present example, the conversion of PFEPVE is 77.0%.

The hydrolysis of -SO ₃ F-groups of the copolymer with their conversion into -SO ₃ H-form is carried out according to the procedure described below.

The resulting film with a thickness of 100 μm was placed in a 500 ml conical flask, filled with 400 ml of a 15% aqueous sodium hydroxide solution, making sure that the solution completely covered the film, and the contents of the flask were heated using a reflux condenser at the boiling temperature of a water bath.

The hydrolysis of the -SO ₂ F-groups of the copolymer is carried out for 10 hours

After hydrolysis is complete, the sodium hydroxide solution is removed and the film is washed with 400 ml portions of distilled water for 30 minutes after each washing. The operation is repeated 3-5 times until the washings are neutral. The completeness of hydrolysis is checked by FTIR spectroscopy on a Shimadzu FTIR-8300 instrument by the disappearance of the absorption band of the -SO ₂ F groups in the region of 1470 cm ^-1 .

A fluoropolymer membrane with ionogenic sulfo groups is obtained in the form of —SO ₃ Na.

The conversion of —SO ₃ Na — groups of the copolymer into the acid form —SO ₃ H is carried out by treating the membrane with a 3% aqueous hydrochloric acid solution. To do this, fill the membrane with 400 ml of a 3% aqueous hydrochloric acid solution, making sure that the solution completely covers the membrane. The membrane is kept in solution for 2 hours at room temperature. After this, the hydrochloric acid solution is drained, the membrane is washed with two portions of 400 ml of distilled water, and the membrane is again filled with 400 ml of a fresh 3% hydrochloric acid solution. The membrane is kept in the solution for 2 hours at room temperature, the hydrochloric acid solution is drained and the membrane is washed 2-3 times in 400 ml portions of distilled water until the washings are neutral. The result is a fluoropolymer membrane in —SO ₃ H form.

The properties of the cation exchange membrane are studied in a hydrated state.

The water content in the membrane aged in distilled water at 25 ° C. for 24 hours is determined as follows.

Wet membranes are weighed, then dried in a vacuum oven at room temperature to constant weight. Having determined the mass of dry membranes, their moisture content (C _W ) is determined by the formula:

C _W (%) = (W ₂ -W ₃ ) 100 / W ₂ ,

where W ₃ is the mass of the dry membrane;

W ₂ - the mass of the wet membrane.

Testing the mechanical properties of hydrated membranes in equilibrium swelling in water (tensile strength (σ _p ), elastic modulus (E), elongation at break (∈)) is carried out on a universal installation for mechanical testing of UTS 10 (Germany) on samples representing a spatula with the dimensions of the working part 20 × 3.5 mm, a thickness of 0.1 mm, with a tensile speed of the samples 10 mm / min The tests are carried out at a temperature of 20 ° C.

The electrical conductivity of the membranes in equilibrium with saturation with water at 20 ° C and 90 ° C is measured using a cell with stainless steel electrodes using the four-probe method according to GOST 20214-74.

Membranes made in accordance with this example had the following characteristics:

- water content of 15.2.0%;

- specific conductivity 0.12 S / cm;

- σ _p 14.1 MPa;

- ∈ 88%;

- E 130 MPa.

Example 2

The synthesis, isolation of the copolymer from latex and the study of its properties is carried out in the same way as in example 1, but with the following process parameters.

Recipe:

PFEPVE 17.9 g

TFE 11.66 g

Ammonium perfluorooctanoate 0.45 g (2.51%) *

Potassium Persulfate 0.15 g (0.84%)

Sodium metabisulfite 0.09 g (0.50%)

Monosubstituted sodium phosphate 0.60 g (3.35%)

Disubstituted sodium phosphate 0.30 g (1.67%)

^* Hereinafter, the percentage of components is calculated based on the mass of PFEPVE.

The process is carried out at 40 ° C and a TFE pressure of 0.52 MPa for 5 hours. The copolymer yield is 20.83 g. PFEPVE conversion is 49.0%.

Characteristics of the copolymer:

- EM 1075

- PTR 13 g / 10 min at 270 ° C and a load of 2.16 kg

Properties of a membrane made from a copolymer according to the technology described in example 1:

- specific conductivity 0.11 S / cm;

- σ _p 16.2 MPa;

- ∈ 85%;

- E 137 MPa.

Example 3

The synthesis, isolation of the copolymer from latex and the study of its properties is carried out in the same way as in example 1, but with the following process parameters.

Recipe:

PFEPVE 17.0 g

TFE 11.0 g

Ammonium perfluorononanoate 0.60 g (3.53%)

Ammonium persulfate 0.26 g (1.53%)

Sodium metabisulfite 0.16 g (0.94%)

Monosubstituted sodium phosphate 0.60 g (3.53%)

Disubstituted sodium phosphate 0.30 g (1.76%)

The process is carried out at 45 ° C and a TFE pressure of 0.48 MPa for 4 hours. The copolymer yield is 22.0 g. The conversion of PFEPVE is 63.0%.

Characteristics of the copolymer:

- EM 920;

- PTR 68 g / 10 min at 220 ° C and a load of 5.0 kg.

Example 4

The synthesis, isolation of the copolymer from latex and the study of its properties is carried out in the same way as in example 1, but with the following process parameters.

Recipe:

PFEPVE 18.3 g

TFE 11.48 g

Ammonium perfluoroheptanoate 0.60 g (3.28%)

Potassium Persulfate 0.15 g (0.82%)

Sodium metabisulfite 0.04 g (0.22%)

Monosubstituted sodium phosphate 0.60 g (3.28%)

Disubstituted sodium phosphate 0.30 g (1.64%)

The process is carried out at 35 ° C and a TFE pressure of 0.52 MPa for 5 hours. The copolymer yield is 22.54 g. The conversion of PFEPVE is 59.0%.

Characteristics of the copolymer:

- EM 930;

- PTR 25 g / 10 min at 220 ° C and a load of 5.0 kg.

Example 5

The synthesis, isolation of the copolymer from latex and the study of its properties is carried out in the same way as in example 1, but with the following process parameters. Unlike the previous examples, the process is stopped at various amounts of charged TFE and in each case the copolymer yield, conversion of PFEPVE and EM copolymer are determined. Other characteristics are measured only for the copolymer obtained at maximum TFE loading.

Recipe:

PFEPVE 17.7 g

TFE: option 1 7.74 g, option 2 10.96 g, option 3 13.22 g

Ammonium perfluorooctanoate 0.45 g (2.54%)

Potassium Persulfate 0.15 g (0.85%)

Sodium metabisulfite 0.09 g (0.51%)

Monosubstituted sodium phosphate 0.60 g (3.39%)

Disubstituted sodium phosphate 0.30 g (1.69%)

The process is carried out at 40 ° C and a TFE pressure of 0.52 MPa for 3 hours (option 1). 5 hours (option 2) and 7 hours (option 3). The yield of copolymer 15.32 g (option 1). 20.38 g (option 2) and 27.3 g (option 3). Conversion of PFEPVE 36.6% (option 1), 49.9% (option 2) and 67.2% (option 3).

Characteristics of the copolymer:

- EM 1050 (option 1), 1040 (option 2), 1025 (option 3);

- PTR 23 g / 10 min at 270 ° C and a load of 2.16 kg or 10 g / 10 min at a load of 1.2 kg.

Properties of a membrane made from a copolymer according to the technology described in example 1:

- water content of 15.5%;

- specific conductivity 0.16 S / cm;

- σ _p 16.0 MPa;

- ∈ 85%;

- E 135 MPa.

This example shows that during the copolymerization, the EM value changes insignificantly, which indicates the formation of a copolymer that is quite uniform in composition even at high conversion of PFEPVE.

Thus, the above examples show that the use of a relatively simple technology for the emulsion copolymerization of TFE and PFEPVE in comparison with the prototype can increase the conversion of PFEPVE to 49-77% while maintaining high properties of the copolymer. It should be noted that the obtained copolymers are compositionally homogeneous, since their equivalent mass varies little with conversion. In addition, the copolymers obtained by the proposed method have a significantly higher melt flow rate in comparison with the copolymers of the prototype and can be processed into a membrane using traditional technologies. The method for producing TFE - PFEPVE copolymers in accordance with the present invention, in comparison with the prototype method, has improved technical and economic indicators (the consumption of perfluorinated surfactant and water for the process is approximately 5 times less).

The claimed invention satisfy the criterion of "novelty", as it first shows the possibility of significantly increasing the conversion of functional comonomer while maintaining the characteristics of the resulting copolymer at a high level.

The claimed invention satisfies the criterion of "inventive step", since there is no information in known and accessible sources of information from which it would be obvious that the method of emulsion copolymerization of TFE and PFPVE could be implemented using a simple technology to achieve optimal target properties of the resulting product.

Compliance with the criterion of "suitability for industrial use" is proved by the test results of the obtained samples, manufacturability, economy and environmental friendliness of the proposed process.

Claims (5)

1. A method of producing a perfluorinated copolymer containing functional groups by emulsion copolymerization of tetrafluoroethylene and perfluoro-2-fluorosulfonylethoxypropyl vinyl ether in the presence of a radical initiator and emulsion stabilizer — a perfluorocarboxylic acid salt, which includes a stage of preliminary emulsification of perfluoro-2-fluorosulfonovinyl ether ethoxylate that the emulsion copolymerization of tetrafluoroethylene and perfluoro-2-fluorosulfonylethoxypropyl vinyl ether is carried out t at a constant pressure of tetrafluoroethylene 0.48-0.52 MPa, stopping the process during the conversion of perfluoro-2-fluorosulfonylethoxy-propyl vinyl ether, and at the stage of preliminary emulsification of perfluoro-2-fluorosulfonyl ethoxypropyl vinyl ether, a homogenizer is used as a dispersant, a type of dispersant at a rotor speed of 8000-12000 rpm, using ammonium salt of perfluorocarboxylic acid C _n F _{2n + 1} COONH ₄ to stabilize the emulsion, where n = 7-9, and the emulsification is carried out in an inert gas. 2. The method according to claim 1, characterized in that the ammonium salt of perfluorocarboxylic acid C _n F _{2n + 1} COONH _{4 is} used in an amount of 2.5-3.5% by weight of perfluoro-2-fluorosulfonylethoxypropyl vinyl ether. 3. The method according to claim 1, characterized in that the emulsification is carried out at a mass ratio of perfluoro-2-fluorosulfonylethoxypropyl vinyl ether / water 0.141-0.152. 4. The method according to claim 1, characterized in that in emulsion copolymerization, the redox initiator uses a redox initiating system of potassium or ammonium persulfate — sodium metabisulfite with a persulfate content of 0.82-1.53%, sodium metabisulfite 0.22-0.94% by weight of perfluoro- 2-fluorosulfonylethoxypropyl vinyl ether and a weight ratio of sodium persulfate / metabisulfite of 1.62-3.75. 5. The method according to claim 1, characterized in that the copolymerization is carried out at a temperature of 35-45 ° C.