KR20220078520A - Method for producing fluorinated copolymer containing perfluoro sulfonyl fluoride group and copolymer prepared therefrom - Google Patents

Abstract

The present invention relates to a method for preparing a fluorine-based copolymer containing a perfluorosulfate group and a copolymer prepared therefrom, using a vinyl perfluorosulfate monomer represented by Formula 1 and an ethylene tetrafluoride monomer represented by Formula 2 and a method for preparing a copolymer, characterized in that polymerization is performed using a perfluorinated ether solvent represented by Chemical Formula 3 as a reaction solvent, and a copolymer prepared therefrom.
<Formula 1>
CF ₂ =CF-O-[CF ₂ -CF(CF ₃ )-O] _m -[CF ₂ ] _n -SO ₂ F
<Formula 2>
CF ₂ =CF ₂
<Formula 3>
CF ₃ CF ₂ CF ₂ -O-[CF ₂ -CF(CF ₃ )-O] _o -[CF ₂ -CF ₂ -O] _p -[CF ₂ -O] _q -CF ₃
In Formula 1, m represents an integer of 0 to 3, and n represents an integer of 2 to 4. In Formula 3, o represents an integer of 0 to 30, and p and q represent an integer of 0 to 40, respectively. According to the present invention, there is an excellent effect of obtaining a perfluorinated sulfate group-containing fluorine-based copolymer that is environmentally friendly using a perfluorinated ether solvent and achieves both a target equivalent value and an appropriate MFI value even in a low pressure range. In addition, ethylene tetrafluoride, vinyl perfluorosulfate, the solubility of the monomer in a solvent is high, so that process stability can be improved, and unreacted monomer recovery is easy.

Description

Method for producing fluorinated copolymer containing perfluorosulfonyl fluoride group and copolymer prepared therefrom

The present invention relates to a method for preparing a fluorine-based copolymer containing a perfluorinated sulfate group and a copolymer prepared therefrom.

A fuel cell is a power source that directly converts chemical energy possessed by chemical fuels into electrical energy, and uses the electrochemical reaction of hydrogen and oxygen, which is the reverse reaction of water electrolysis. Since a combustion process that burns fuel is not required, thermal efficiency is high, and there is no emission of pollutants such as dust or chemicals.

In addition, the fuel cell is a useful cutting-edge technology in terms of operation of the power system, such as can be manufactured in various capacities and can be easily installed within the power demand area, thereby reducing transmission and substation facilities.

Fuel cells are broadly classified into phosphoric acid type (PAFC), molten carbonate type (MCFC), solid electrolyte type (SOFC), and solid polymer type (PEMFC) according to the type of electrolyte. Among them, solid polymer fuel cells have a high current density and are being actively developed, such as being used in automobiles, which are representative means of transportation.

If we look at the technical composition of the fuel cell power generation system, it can be divided into fuel cell main body technology and system technology. It is divided into stack configuration technology and stack performance measurement technology. System technology consists of system configuration technology, such as development of peripheral devices (reformer, inverter, heat recovery device), and overall system technology such as system design and operation.

Through the research process for decades, many research results have been carried out from unit cell manufacturing technology to stacking and system configuration, and it is almost in the commercialization stage. On the other hand, fuel cell material technology, which is the most basic, affects the entire system and is an important factor influencing the overall efficiency, is in a state of incomplete research and development. In particular, polymer-type fuel cells are only 2-3 materials of the perfluorosulfonic acid (PFSA) series, which have almost similar chemical structures to electrolytes that can be used worldwide. There were significant restrictions on application and dissemination.

The perfluorosulfuric acid group-containing fluorine-based copolymer is typically prepared by copolymerization using a perfluorosulfate group-containing vinyl ether monomer and ethylene tetrafluoride, and using a radical initiator. This may be accomplished by solution polymerization or emulsion polymerization using a CFC solvent. Vinyl perfluorosulfate monomer and ethylene tetrafluoride have a large difference in reactivity and have a relatively long side chain, so the conversion rate of the vinyl perfluorosulfate monomer is low. Therefore, the vinyl perfluorosulfate monomer must be recovered and recycled. In this case, when the emulsion polymerization method is used, since the unreacted vinyl monomer is dispersed in water, the monomer recovery and recycling process is complicated, and there is a problem in the recovery rate.

In addition, the most commercially used solution polymerization method at present has been used global warming-causing substances such as Freon-113, and these CFC and HCFC solvents are not available for industrial mass use after the Montreal Protocol was declared on January 1, 1989, and Even if you use it, it is not easy.

Accordingly, the present inventors consider various factors such as reaction solvent recovery possibility, absorption solubility and reaction participation degree of gaseous ethylene tetrafluoride, and environmental friendliness, and solve the above problems and use an eco-friendly novel reaction solvent and optimal perfluorine As a result of research to develop a method for producing a sulfate group-containing fluorine-based copolymer, the present invention was reached.

Korean Patent Publication No. 1997-0015616 (April 28, 1997)

An object of the present invention is to provide a method for preparing a fluorine-based copolymer containing a perfluorinated sulfate group and a copolymer prepared therefrom.

In order to achieve the above object,

In one aspect of the present invention,

A method comprising the step of polymerizing a vinyl perfluorosulfate monomer represented by the following formula (1) and an ethylene tetrafluoride monomer represented by the following formula (2), wherein the polymerization using a perfluorinated solvent represented by the following formula (3) as a reaction solvent It provides a method for producing a fluorine-based copolymer containing a perfluorinated sulfate group, characterized in that.

<Formula 1>

CF ₂ =CF-O-[CF ₂ -CF(CF ₃ )-O] _m -[CF ₂ ] _n -SO ₂ F

<Formula 2>

CF ₂ =CF ₂

<Formula 3>

CF ₃ CF ₂ CF ₂ -O-[CF ₂ -CF(CF ₃ )-O] _o -[CF ₂ -CF ₂ -O] _p -[CF ₂ -O] _q -CF ₃

In Formula 1, m represents an integer of 0 to 3, and n represents an integer of 2 to 4.

In Formula 3, o represents an integer of 0 to 30, and p and q represent an integer of 0 to 40, respectively.

In another aspect of the present invention,

It provides a fluorine-based copolymer containing a perfluorinated sulfate group prepared by the manufacturing method provided in one aspect of the present invention.

In another aspect of the present invention,

The manufacturing method provided in one aspect of the present invention is performed,

A reactor comprising a vinyl perfluorosulfate monomer and a reaction solvent; and

It provides a reaction system comprising a; a gas phase supply device for supplying ethylene tetrafluoride (TFE) to the reactor.

According to the present invention, a fluorine-based copolymer containing a perfluorinated sulfate group is prepared using a perfluorinated ether solvent to obtain a perfluorinated sulfate group-containing fluorine-based copolymer that is environmentally friendly and achieves both a target equivalent value and an appropriate MFI value even in a low pressure range There are excellent effects that can be

In addition, ethylene tetrafluoride, vinyl perfluorosulfate, the solubility of the monomer in the solvent is high, so process stability can be improved, and unreacted monomer recovery is easy.

1 is a conceptual diagram showing a reaction system for preparing a perfluorinated sulfate group-containing fluorine-based copolymer according to the present invention.

Since the present invention can make various changes and thus various embodiments can be made, specific embodiments will be presented below and described in detail.

In addition, all terms in this specification that are not specifically defined may be used in a meaning that can be understood by all those of ordinary skill in the art to which the present invention belongs.

However, it should be understood that the present invention is not intended to be limited only to the specific embodiments to be described below, and includes all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Accordingly, there may be other equivalents and modifications to the embodiment described herein, and the embodiment presented herein is only the most preferred embodiment.

Hereinafter, the present invention will be described in detail.

In one aspect of the present invention,

A method comprising the step of polymerizing a vinyl perfluorosulfate monomer represented by the following formula (1) and an ethylene tetrafluoride monomer represented by the following formula (2), wherein the polymerization using a perfluorinated solvent represented by the following formula (3) as a reaction solvent A method for producing a fluorine-based copolymer containing a perfluorinated sulfate group, characterized in that:

<Formula 1>

CF ₂ =CF-O-[CF ₂ -CF(CF ₃ )-O] _m -[CF ₂ ] _n -SO ₂ F

<Formula 2>

CF ₂ =CF ₂

<Formula 3>

CF ₃ CF ₂ CF ₂ -O-[CF ₂ -CF(CF ₃ )-O] _o -[CF ₂ -CF ₂ -O] _p -[CF ₂ -O] _q -CF ₃

In Formula 1, m represents an integer of 0 to 3, n represents an integer of 2 to 4,

In Formula 3, o represents an integer of 0 to 30, and p and q represent an integer of 0 to 40, respectively.

The boiling point of the perfluorinated ether solvent may be 50 to 100 °C. As a specific example of the perfluorinated ether solvent, commercially available HT70 (trade name) may be used, but is not limited thereto.

The method for preparing the copolymer of the present invention uses an ethylene tetrafluoride monomer and a vinyl perfluorosulfate monomer represented by the formula (1).

The method for preparing the copolymer of the present invention uses a perfluorinated ether solvent represented by Chemical Formula 3 as a reaction solvent.

The perfluorinated ether solvent has a very low global warming potential and is eco-friendly, and has a high absorption solubility of ethylene tetrafluoride as a comonomer, so it has an appropriate molecular weight and composition by controlling the concentration of vinyl ether perfluorosulfate and ethylene tetrafluoride in the reaction solution. There is an advantage in that the copolymer can be prepared.

In addition, since the absorption solubility of ethylene tetrafluoride is high, the reaction temperature can be lowered, thereby reducing the risk of explosion and improving process stability.

Freon-113, which has been used as a conventional reaction solvent, has a bp of 47.7° C., and there is a problem that the reaction pressure may increase overall when using it. can be prevented

In addition, by selecting a perfluorinated ether solvent having an appropriate boiling point difference from the vinyl perfluorosulfate monomer, it is possible to facilitate separation and purification between the unreacted monomer and the reaction solvent, thereby increasing the economic feasibility of the process. In addition, the perfluorinated ether solvent is a neutral material and has the advantage that there is no possibility of impurities being generated during the reaction because it is not reactive with the reaction raw materials.

The copolymer polymerization reaction is

Before the polymerization reaction starts, the vinyl perfluorosulfate monomer may be supplied in a dissolved state in the solvent, and the ethylene tetrafluoride monomer may be supplied in a gas phase to proceed with the polymerization reaction.

The polymerization reaction may be a batch reaction or a continuous reaction, but will be described below according to the batch reaction.

The method may be to polymerize in a supplied state in which the vinyl perfluorosulfate monomer is dissolved in a ratio of 5 to 90 wt% based on the total weight of the vinyl perfluorosulfate monomer and the reaction solvent, preferably Preferably, it may be supplied in a ratio of 10 to 70% by weight.

When the vinyl perfluorosulfate monomer is less than 5% by weight, polymerization efficiency may be low and a low molecular weight copolymer tends to be produced, and when it is 90% by weight or more, the desired copolymerization ratio of ethylene tetrafluoride as a comonomer is achieved In order to do this, it may have to be supplied at a high concentration, the pressure of ethylene tetrafluoride supplied in a gaseous state must be maintained high, and there may be a tendency to produce a low-equivalent copolymer,

In order to prepare a copolymer having desired physical properties, the ratio and the like may be adjusted as necessary.

The method may use a radical initiator as a polymerization initiator.

Since the method uses ethylene tetrafluoride, which is highly explosive, it may be suitable to use an initiator that is decomposed at a low temperature.

The method may be to use the all-fluorine-based initiator represented by the formula (4).

<Formula 4>

{CF ₃ CF ₂ CF ₂ -[O-CF(CF ₃ )(CF ₂ )]r-[O-CF(CF ₃ )]s-CO-O-} ₂

In Formula 4, r represents an integer of 0 to 10, and s represents an integer of 0 to 1.

When a hydrocarbon-based radical initiator is used as the polymerization initiator, it is difficult to participate in the reaction due to poor solubility with the reaction mixture to be polymerized compared to the all-fluorine-based polymerization initiator. The durability is lowered, and there is a high possibility that defects such as monomolecular gas are generated.

On the other hand, the all-fluorine-based initiator has an advantage of relatively excellent thermal and chemical stability.

The pressure of the ethylene tetrafluoride supplied in the gas phase into the reactor for the polymerization may be 2.0 to 5.0 atmG, preferably 2.5 to 4.0 atmG, and more preferably 3.0 to 3.7 atmG. If the pressure of the ethylene tetrafluoride is less than 2.0 atmG, the polymerization rate is slowed and the yield is extremely low. This may cause a problem that the performance as an ionomer does not appear properly.

The conversion rate of the vinyl perfluorosulfate monomer may be within 30%, preferably within 15%, but is not limited thereto.

The unreacted monomer and reaction solvent may be recovered and recycled after the reaction by separating the product through distillation.

The method may be carried out using a reaction system including a reactor including a vinyl perfluorosulfate monomer and a perfluorinated ether solvent and a gas phase supply device for supplying ethylene tetrafluoride (TFE).

According to the present invention, a fluorine-based copolymer containing a perfluorinated sulfate group is prepared using a perfluorinated ether solvent to obtain a perfluorinated sulfate group-containing fluorine-based copolymer that is environmentally friendly and achieves both a target equivalent value and an appropriate MFI value even in a low pressure range There are excellent effects that can be

In addition, ethylene tetrafluoride, vinyl perfluorosulfate, the solubility of the monomer in the solvent is high, so process stability can be improved, and unreacted monomer recovery is easy.

In another aspect of the present invention,

It provides a fluorine-based copolymer containing a perfluorinated sulfate group prepared by the method for preparing the copolymer provided in one aspect of the present invention.

According to the present invention, a fluorine-based copolymer containing a perfluorinated sulfate group is prepared using a perfluorinated ether solvent to obtain a perfluorinated sulfate group-containing fluorine-based copolymer that is environmentally friendly and achieves both a target equivalent value and an appropriate MFI value even in a low pressure range There are excellent effects that can be

In addition, ethylene tetrafluoride and vinyl perfluorosulfate have high solvent solubility of monomers, so process stability can be improved, and unreacted monomers can be easily recovered.

In another aspect of the present invention,

The method for preparing the copolymer provided in one aspect of the present invention is carried out,

A reactor comprising a vinyl perfluorosulfate monomer and a perfluorinated solvent; and

It provides a reaction system comprising a; a gas phase supply device for supplying ethylene tetrafluoride (TFE) to the reactor.

The vinyl perfluorosulfate monomer is contained in the reactor in a state of being dissolved in a perfluorinated ether solvent.

The reaction system of the present invention includes a reactor comprising a vinyl perfluorosulfate monomer and a perfluorinated solvent.

The reactor includes a perfluorinated ether solvent as a reaction solvent.

The reactor may be a high-pressure reactor, and the material of the reactor may be a stainless steel material, but is not limited thereto.

The reaction system of the present invention includes a gas phase supply device for supplying ethylene tetrafluoride (TFE).

The gas phase supply device supplies gaseous ethylene tetrafluoride into the reactor so that the ethylene tetrafluoride is dissolved in a monomer and a reaction solvent as vinyl perfluorosulfate contained in the reactor to perform a polymerization reaction.

The reaction system may further include a pressure control system for maintaining the internal pressure constant.

The reaction system may further include an adsorption tower for removing the polymerization inhibitor of ethylene tetrafluoride.

A stirrer is installed inside the reactor, and the stirrer may be an anchor type high-speed stirrer.

Since the viscosity of the copolymer solution prepared as the polymerization reaction proceeds in the reactor is very high and its solubility in the reaction solution is low, it is important to increase the stirring efficiency for smooth reaction progress. When the anchor-type high-speed stirrer is used, stirring efficiency can be improved.

The ratio of the diameter (d) of the stirrer to the diameter (D) of the reactor is 0.5 to 0.97 can be

A reaction system according to an embodiment of the present invention is shown in FIG. 1 .

Hereinafter, the present invention will be described in more detail through Examples and Experimental Examples. The scope of the present invention is not limited to specific examples and experimental examples, and should be construed according to the appended claims. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

<Preparation Example 1> Preparation of vinyl perfluorosulfate monomer

Fluorinated sulfonyl vinylether (FSVE) represented by the chemical formula of CF ₂ =CF-O-CF ₂ -CF(CF ₃ )-O-CF ₂ -CF ₂ -SO ₂ F as a vinyl perfluorosulfate monomer was prepared. The synthesis process is shown in Chemical Formula 5 below.

First, F-sultone was synthesized by reacting ethylene tetrafluoride with γ-form SO ₃ (①), and PSAF was synthesized by ring-opening reaction of F-sultone (②).

Then, after synthesizing PSAF-HFPO to which 2 mol of HFPO was added by addition reaction of PSAF and HFPO anion (③), PSAF-HFPO and Na ₂ CO ₃ were reacted (④), and thermal decomposition of PSAF-HFPO-salt was performed. FVE was synthesized through (⑤). Since impurities are generated at each step of the synthesis process, high-purity purification was performed.

<Formula 5>

<Preparation Example 2> Preparation of ethylene tetrafluoride (TFE)

Ethylene tetrafluoride (TFE) was prepared through pyrolysis and distillation processes.

Freone-22 (CHClF ₂ ) was passed through a stainless tubular reactor at a reaction temperature of 850 °C, atmospheric pressure, and contact time of 1 sec or less. A gas mixture having a conversion rate of 70% or more and a ratio of TFE and HFP (hexafluoropropylene, Hexafluoropropylene) of about 90:10 mol% was obtained.

The obtained gas mixture was passed through an absorption tower to remove hydrochloric acid gas, dried and then compressed. Thereafter, TFE with a purity of 99% or more was continuously obtained through three or more pressure-freezing distillation columns. The obtained TFE was added with a turpene polymerization inhibitor to prevent explosion and stored in a storage tank at 3.5 atmG or less.

<Preparation Example 3> Preparation of perfluorinated solvent

As a perfluorinated ether solvent represented by Chemical Formula 3, a PFPE (Perfluoropolyether) type solvent having a CF ₃ group attached to the side chain was prepared.

After anionic ring-opening polymerization of HFPO (Hexafluoro propylene oxide) under a metal fluoride catalyst such as CsF or KF, the terminal groups were prefluorinated using SbF ₅ or F ₂ , followed by distillation by molecular weight using a thin film distillation device.

<Production Example 4> Preparation of perfluorinated solvent

A linear PFPE (Perfluoropolyether) type solvent was prepared as a perfluorinated ether solvent represented by Chemical Formula 3 above.

After polymerization of ethylene tetrafluoride gas with oxygen through continuous UV photopolymerization at about -50 °C and atmospheric pressure, the terminal group was prefluorinated using SbF ₅ or F ₂ , followed by distillation by molecular weight using a thin film distillation device. .

<Preparation Example 5> Preparation of all-fluorine-based initiator

A monomolecular type all-fluorine-based initiator was prepared as the all-fluorine-based initiator represented by Chemical Formula 4 above.

Using R-113 or the perfluorinated solvent prepared in Preparation Example 4 as a solvent, NaOH aqueous solution and 30% H ₂ O ₂ were sequentially added at -10 to 0 ^o C, and then heptafluorobutyryl chloride [CF ₃ CF ₂ CF ₂ COCl] was slowly added so that the temperature of the reactant did not rise, and stirred for about 1 hour to complete the reaction. Ice-cold H ₂ O was added and the organic layer was extracted to prepare a monomolecular all-fluorine-based initiator [CF ₃ CF ₂ CF ₂ COO] ₂ .

<Preparation Example 6> Preparation of all-fluorine-based initiator

A PEPE-type all-fluorine-based initiator was prepared as the all-fluorine-based initiator represented by Chemical Formula 4 above.

Using R-113 or the perfluorinated solvent prepared in Preparation Example 4, NaOH aqueous solution and 30% H ₂ O ₂ were sequentially added at -10 to 0 ^o C, and then anionic polymerization of HFPO under a metal fluoride catalyst was obtained after ring opening. A PFPE-type compound having a terminal group of -COF [CF ₃ CF ₂ CF ₂ OCF(CF ₃ )COF] was slowly added so as not to increase the temperature of the reactant, and stirred for about 1 hour to complete the reaction. Ice-cold H ₂ O was added and the organic layer was extracted to prepare a PFPE-type initiator [CF ₃ CF ₂ CF ₂ OCF(CF ₃ )COO] ₂ .

The monomolecular all-fluorine-based initiator of Preparation Example 5 and the PFPE-type initiator of Preparation Example 6 were left at -20 ^o C for 24 days, and then the degree of decomposition was analyzed to evaluate their stability. As a result, the monomolecular all-fluorine-based initiator (Preparation Example 5) was decomposed by 3% and the PFPE-type initiator (Preparation Example 6) by 17%, indicating that the monomolecular all-fluorine-based initiator was more stable than the PFPE-type initiator.

<Examples 1 to 5, and Comparative Examples 1 and 2>

A 3L volume reactor was prepared in which the inside was electropolished in a vacuum, and an anchor type stirrer and a baffle were installed. As the vinyl perfluorosulfate monomer and reaction solvent of Preparation Example 1, the perfluorinated solvent was added to fill 80% of the reactor. As the perfluorinated solvent, the perfluorinated solvent prepared in Preparation Example 4 was used.

After uniformly stirring the monomer and reaction solvent with vinyl perfluorosulfate contained in the reactor, nitrogen is charged up to 1.5 atmG, cooled to -70°C using liquid nitrogen, and then freeze-thaw cycle using nitrogen and ethylene tetrafluoride. was performed 3 times.

After raising the reactor temperature to 45 °C, ethylene tetrafluoride obtained in Preparation Example 2 was charged to a desired constant pressure using a pressure control system, and 1.5 mL of the all-fluorine-based initiator solution (5%) of Preparation Example 5 was added to react was started. After the reaction was carried out for about 3 hours, the temperature was lowered, the remaining ethylene tetrafluoride gas was transferred to the storage tank, and the reaction was terminated.

The reaction product was distilled in a vacuum to recover the reaction solvent and vinyl perfluorosulfate monomer in order, and finally to recover the prepared copolymer. The equivalent value and Melt Flow Index (MFI) of the obtained copolymer were measured.

In Comparative Examples 1 and 2, R113 (Comparative Example 1) or R113a (Comparative Example 2) was used in the same manner as above, but instead of the perfluorinated solvent prepared in Preparation Example 4 as the reaction solvent.

R-113a (reagent name: 1,1,1-trichloro-trifluoroethane, trade name: R-113a, manufacturer: Career Henan Chemical Co.)

R113 (reagent name: 1,1,2-trichloro-trifluoroethane, trade name: R-113)

The reaction conditions used in the preparation of the perfluorinated sulfate group-containing fluorine-based copolymers according to Examples 1 to 5 and Comparative Examples 1 and 2 and the MFI and equivalent values of the prepared copolymers are shown in Table 1 below.

Example Composition of perfluorinated vinyl sulfate monomer (wt%) Boiling Point of Perfluorinated Ether Solvent Used
(℃) Ethylene tetrafluoride pressure (atmG) of agitator
Size (d/D) MFI (g/10 min, 270°C) equivalent One 30 50-60 3.2-3.5 0.8 24.80 952 2 30 60-70 3.2-3.8 0.7 10.40 971 3 30 60-70 3.4-3.9 0.8 5.13 1053 4 30 70-80 3.7-4.1 0.9 0.45 1099 5 30 70-80 3.9-4.4 0.6 0.50 1136 comparative example Composition of fluorine-based vinyl sulfate monomer (wt%) reaction solvent Ethylene tetrafluoride pressure (atmG) Size of agitator (d/D) MFI (g/10 min, 270°C) equivalent One 30 R-113 3.7-4.2 0.9 not measurable 1205 2 30 R-113a 3.6-4.1 0.8 51 1124

According to the results of Table 1, when R-113 or R-113a is used as the reaction solvent, it can be confirmed that the MFI is high at an unmeasurable level (200 g/min or more) or shows a large value. Therefore, it can be confirmed that by using the perfluorinated ether solvent according to the present invention as the reaction solvent, it is possible to synthesize both the relatively low MFI value and the equivalent value at an ideal level.

On the other hand, in the present invention, ethylene tetrafluoride is continuously injected until the end of the reaction rather than a one-time input, and the pressure of ethylene tetrafluoride means the pressure condition for injecting ethylene tetrafluoride, and through this, the will regulate the pressure.

Claims (12)

Including the step of polymerizing a vinyl perfluorosulfate monomer represented by the following formula (1) and an ethylene tetrafluoride monomer represented by the following formula (2), polymerization using a perfluorinated solvent represented by the following formula (3) as a reaction solvent A method for producing a fluorine-based copolymer containing a perfluorinated sulfate group, characterized in that:

<Formula 1>
CF ₂ =CF-O-[CF ₂ -CF(CF ₃ )-O] _m -[CF ₂ ] _n -SO ₂ F

<Formula 2>
CF ₂ =CF ₂

<Formula 3>
CF ₃ CF ₂ CF ₂ -O-[CF ₂ -CF(CF ₃ )-O] _o -[CF ₂ -CF ₂ -O] _p -[CF ₂ -O] _q -CF ₃

In Formula 1, m represents an integer of 0 to 3, n represents an integer of 2 to 4,
In Formula 3, o represents an integer of 0 to 30, and p and q represent an integer of 0 to 40, respectively.
According to claim 1,
Before the polymerization reaction starts, the vinyl perfluorosulfate monomer is supplied in a dissolved state in the solvent, and the ethylene tetrafluoride monomer is supplied in the gas phase so that the polymerization reaction proceeds. Way.
3. The method of claim 2,
Based on the total weight of the vinyl perfluorosulfate monomer and the reaction solvent before the start of the polymerization reaction, the vinyl perfluorosulfate monomer is dissolved in a ratio of 5 to 90% by weight, a fluorine-containing perfluorosulfate group A method for preparing a copolymer.
According to claim 1,
The method is a method for producing a fluorine-based copolymer containing a perfluorinated sulfate group, characterized in that using the all-fluorine-based initiator represented by the formula (4).

<Formula 4>
{CF ₃ CF ₂ CF ₂ -[O-CF(CF ₃ )(CF ₂ )]r-[O-CF(CF ₃ )]s-CO-O-} ₂

In Formula 4, r represents an integer of 0 to 10, and s represents an integer of 0 to 1.
According to claim 1,
The method for producing a fluorine-based copolymer containing a perfluorinated sulfate group, characterized in that the pressure of the ethylene tetrafluoride is 2.0 to 5.0 atmG.
According to claim 1,
The method for producing a fluorine-based copolymer containing a perfluorosulfate group, characterized in that the conversion rate of the vinyl perfluorosulfate monomer is within 30%.
A fluorine-based copolymer containing a perfluorinated sulfate group prepared by the method of claim 1.
The method of claim 1 is carried out,
A reactor comprising a vinyl perfluorosulfate monomer and a perfluorinated solvent; and
A gas phase supply device for supplying ethylene tetrafluoride (TFE) to the reactor; characterized in that it comprises, the reaction system.
9. The method of claim 8,
The reaction system, characterized in that it further comprises a pressure control system for maintaining a constant pressure inside the reactor.
9. The method of claim 8,
The reaction system, characterized in that it further comprises an adsorption tower for removing the polymerization inhibitor of ethylene tetrafluoride.
9. The method of claim 8,
A stirrer is installed inside the reactor, and the agitator is an anchor type high-speed stirrer, characterized in that the reaction system.
12. The method of claim 11,
A reaction system, characterized in that the ratio of the diameter (d) of the stirrer to the diameter (D) of the reactor is 0.5 to 0.97.

Images