JPS5930165B2 - Method for producing fluoropolymer containing ion exchange group - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a fluoropolymer containing an ion exchange group, and more specifically, the present invention relates to a method for producing a fluoropolymer containing a carboxylic acid type cation exchange group that can be effectively used as an ion exchange membrane diaphragm in electrolysis of an aqueous electrolyte solution. The present invention relates to a method for producing a fluorophore polymer by copolymerization reaction without a solvent or in an organic solvent.

A diaphragm electrolysis method is known in which a diaphragm is used to partition the cathode and anode of an electrolytic cell, and sodium hydroxide is produced in the cathode chamber by supplying, for example, an aqueous sodium chloride solution to the anode chamber and performing electrolysis.

Recently, it has been proposed to use, as a diaphragm, a cation exchange resin membrane that is substantially impermeable to electrolyte and selectively permeable only to alkali metal ions, in place of the conventional asbestos diaphragm. Among these, fluorine-containing resin cation exchange membranes having alkali resistance and chlorine resistance have been proposed as excellent. For example, fluororesin cation exchange membranes having carboxylic acid groups or sulfonic acid groups as ion exchange groups are known. JP-A-48-37395, JP-A-Sho 5
See Publication No. 0-120492, etc. Therefore, the carboxylic acid type fluororesin cation exchange membrane not only provides high purity alkali hydroxide in the diaphragm electrolysis method of aqueous alkali chloride solutions, but also enables operation at high current efficiency and high current density. Furthermore, it has been found that a high concentration of alkali hydroxide can be provided to the cathode chamber.

For example, even when the concentration of produced sodium hydroxide is 40% or more, the current efficiency can be maintained at 90% or more, which is an excellent performance. However, so far, there has been no proposal for a means for smoothly and advantageously producing such a fluoropolymer containing a carboxylic acid type cation exchange group. According to the research of the present inventors, in order to achieve the above-mentioned high electrolytic performance, the ion exchange capacity of the ion exchange group-containing fluorophore polymer should be adjusted to 0.5 to 4 milliequivalents/g dry resin, preferably 0. It is important to make the molecular weight of the polymer as high as possible in the range of .8 to 3 milliequivalents/gram dry resin, especially 1.0 to 2.2 milliequivalents/gram dry resin. It has been found that.

Furthermore, if the ion exchange capacity is simply increased, the molecular weight of the polymer tends to decrease, resulting in a decrease in mechanical strength (eg, breaking strength, breaking elongation, etc.) when formed into a membrane. Based on the above findings, the present inventors have provided the following information regarding the means for producing a fluoropolymer containing a carboxylic acid type cation exchange group:
In particular, various studies and studies have been carried out in order to provide a smooth and advantageous polymerization method that can provide a high molecular weight polymer even with a high ion exchange capacity. As a result, fluorinated olefin compounds such as tetrafluoroethylene and carboxylic acid type functional monomers can be combined with or without the use of an inert organic solvent under the action of a polymerization initiator such as a peroxy compound. The inventors have discovered that the above object can be achieved by copolymerizing under specific conditions. That is, high ion exchange capacity and high molecular weight can be achieved by carrying out the copolymerization reaction at a ratio of 0 to 10 moles of inert organic solvent per mole of carboxylic acid type functional monomer and at a pressure of 6 kg/d or more. The copolymer having the above-mentioned properties can be produced smoothly and advantageously. Furthermore, the copolymerization reaction rate is also good, and by selecting the proportions of the fluorinated olefin compound and the functional monomer, the TQ defined below is 150°C.
A fluoropolymer having an ion exchange capacity of 0.5 to 4 milliequivalents/gram dry resin is thus obtained. In particular, the effects of the present invention can be more advantageously achieved by a so-called bulk polymerization method that does not use an inert organic solvent. Thus, the present invention has been completed based on the above-mentioned new findings, and it is based on the above-mentioned novel findings. A certain functional monomer is copolymerized by the action of a polymerization initiation source, and the functional monomer content is 1 to 5.
In a method for producing a fluoropolymer containing an ion exchange group, the copolymerization reaction pressure is 6 kg at a ratio of 0 to 10 mol of an inert organic solvent per 1 mol of the functional monomer. The copolymerization reaction is carried out at a temperature of /Cd or higher to produce a copolymer having a TQ defined below of 150°C or higher and an ion exchange capacity of 0.5 to 4 meq/g dry resin. A method for producing a fluoropolymer containing an ion exchange group is provided.

As used herein, the term "TQ" is defined as follows.

That is, the volume flow rate 100 md, which is related to the molecular weight of the copolymer.
Examples include temperature that indicates /second. Next, as the fluorinated ethylenically unsaturated monomer (), ethylene tetrafluoride,
Examples include ethylene chloride trifluoride, propylene hexafluoride, ethylene trifluoride, vinylidene fluoride, vinyl fluoride, etc. Preferably, the general formula CF2=CZZ' (where Z, .l are fluorine atoms, chlorine atom, hydrogen atom, or -CF3) is defined as TQ.

In this X, the volume flow rate is 17111L in diameter and 2m77 in length at a constant temperature of the copolymer under pressure of 30k9/d! The amount of copolymer flowing out is W!
It is expressed in units of d/second. In the present invention,
It is important to use a polymerizable monomer containing a carboxylic acid group or a functional group convertible to a carboxylic acid group as the functional monomer.

Considering the chlorine resistance, oxidation resistance, etc. of the resulting polymer, it is usually desirable that the carboxylic acid type functional monomer () be a fluorovinyl compound. , = general formula (in this X, l is 0-3, m is O-1, n is O-
is an integer of 12, X is a fluorine atom or -CF3, Y. Y' is a fluorine atom or a perfluoroalkyl group having 1 to 10 carbon atoms.

Moreover, A is oligo-CNl-COFl-COOHl-
Fluorovinyl represented by COORl, -COOM or -COONR2R3, R1 is an alkyl group having 1 to 10 carbon atoms, R2 and R3 are a hydrogen atom or R1, and M is an alkali metal or a quaternary ammonium group) Examples include compounds. From the viewpoint of performance and availability, X is a fluorine atom, Y is -CF3, Y' is a fluorine atom, and l is O~1
, m is O-1, n is 0-8, and A is preferably -COF or -COORl from the viewpoint of copolymerization reactivity, etc., and R1
is preferably a lower alkyl group having 1 to 5 carbon atoms.

Preferred representative examples of the fluorovinyl compounds include olefin compounds represented by the general formula CH2=CR4R5 (in which R4 and R represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aromatic nucleus); (), CF2=CFORf
(Rf represents a perfluoroalkyl group having 1 to 10 carbon atoms), CF2=CF-C
F=CF2, CF2=CFO(CF2)1~40CF=
One or more types of divinyl monomers such as CF2 and other functional monomers such as sulfonic acid type functional groups can also be used in combination.

Preferred representative examples of the olefin compound () include ethylene, propylene, butene-1, isobutylene, styrene, α-methylstyrene, benzene-1, hexene-1
, heptene-1,3-methyl-butene-1,4-methyl-pentene-1, etc. Among them, ethylene, propylene,
Particular preference is given to using isobutylene and the like. Furthermore, for example, by using a divinyl monomer in combination, it is possible to crosslink the resulting copolymer and improve the mechanical strength when formed into a membrane. In the ion-exchange group-containing fluoropolymer of the present invention, the composition ratios of the functional monomer (1), the fluorinated olefin compound (), and the olefin compound () and other components are as follows: This is important because it is related to all performances when used as an exchange membrane.

First, the amount of the functional monomer (1) is directly related to the ion exchange capacity, but it is preferably 1 to 50 mol%, preferably 3 to 35 mol%, particularly 5 to 30 mol% in the copolymer. It is. If the amount of the monomer (1) is too large, the mechanical strength of the ion exchange membrane will be impaired, and furthermore, the ion exchange performance will decrease due to an increase in water content. It is not preferred because it does not exhibit ion exchange function. Therefore, the above (1) in the copolymer of the present invention
) The rest of the compounds in () are occupied by the above () and other compounds in (). This is important because it is closely related to the following.

Therefore, when the olefin compound () is used in combination, the molar ratio of the olefin compound ()/fluorinated olefin compound () is preferably 5/95 to 70/30, particularly 1
It is suitable to set it to 0/90 - 60/40. Furthermore, when fluorovinyl ether, divinyl ether, etc. are used together, 30% by mole or less, preferably 2% by mole in the copolymer.
It is preferable to use a proportion of about 20 mol %. In the present invention, the ion exchange capacity is selected from a wide range of 0.5 to 4 milliequivalents/gram dry resin, but the characteristic feature is that even if the ion exchange capacity is increased, the molecular weight of the produced copolymer remains Therefore, the mechanical properties and durability of the copolymer do not deteriorate.

The ion exchange capacity varies depending on the type of copolymer within the above range, but is preferably 0.8 to 3 meq/g dry resin, particularly 1.0 to 2.2 meq/g dry resin. is preferable in terms of mechanical properties and electrochemical performance as an ion exchange membrane. In addition, the molecular weight of the fluorocarbon polymer obtained in the present invention is important because it is related to the mechanical performance and film formability as an ion exchange membrane. 340℃
The temperature is particularly preferably about 180 to 300°C. In the present invention, it is important that the copolymerization reaction between the functional monomer and the fluorinated olefin compound is carried out with or without the use of a specific amount of an inert organic solvent.

That is, a so-called bulk polymerization method that does not use an inert organic solvent is preferred, but when an inert solvent is used, the amount used should be 10 mol or less, preferably 5 mol, per 1 mol of functional monomer. It is important to control and implement the following.
If the amount of the inert organic solvent used is too large, the copolymerization reaction rate will drop significantly, making it difficult to obtain a high copolymer yield, and in some cases, the copolymer may not be obtained. Furthermore, if the amount of inert organic solvent is too large, a high molecular weight cannot be achieved when a high ion exchange capacity is used. Furthermore, the following difficulties are recognized in the use of large amounts of inert organic solvents. For example, there are disadvantages in terms of operation, such as an increase in the size of the reactor and the complexity of recovering the liquid medium. Therefore, in the present invention, it is a preferred embodiment to carry out the copolymerization reaction using as little inert organic solvent as possible, 5 moles or less, particularly 3 moles or less, per mole of functional monomer. In particular, in the present invention, embodiments in which no inert organic solvent is used, i.e., 0 moles of inert organic solvent per mole of functional monomer, may give the best results for the intended purpose. It is something. Next, in the present invention, it is important to employ a copolymerization reaction pressure of 6 kg/Cd or more. If the copolymerization reaction pressure is too low, the copolymerization reaction rate cannot be maintained at a level that is practically satisfactory, and there are also difficulties in forming a high molecular weight copolymer. In addition, if the copolymerization reaction pressure is too low, the ion exchange capacity of the resulting copolymer will become extremely high, and the mechanical strength will decrease due to increased water content.
The tendency for ion exchange performance to decline will increase. still,
The copolymerization reaction pressure is desirably selected from 50k9/Cd or less, taking into consideration the reaction apparatus or work operation in industrial implementation. Although it is possible to employ a copolymerization reaction pressure higher than this range, it may not proportionately improve the objectives of the present invention. Therefore, in the present invention, it is optimal to select the copolymerization reaction pressure from the range of 6 to 50 k9/Cdl, preferably 9 to 30 kg/Cd. Various examples of inert organic solvents that can be used in the present invention include those that do not inhibit the copolymerization reaction between the fluorinated olefin compound and the specific functional monomer and that cause little chain transfer. Preferred specific examples include solvents consisting of fluorinated or fluorinated chlorinated saturated hydrocarbons, which are usually known as so-called fluorocarbon-based solvents.

Examples of chlorofluorocarbon solvents include dichlorodifluoromethane, trichloromonofluoromethane, dichloromonofluoromethane, monochlorodifluoromethane, chlorotrifluoromethane, trichlorotrifluoroethane, dichlorotetrafluoroethane, fluorochloropropane, perfluoropropane, and perfluorocyclobutane. Those having 1 to 4 carbon atoms can be mentioned, and these can be used alone or in a mixture of two or more kinds. In the present invention, a hydrocarbon made of a fluorinated or fluorinated chlorinated saturated hydrocarbon containing no hydrogen atom in its molecule is preferred, and trichlorotrifluoroethane is particularly preferred. In addition, organic solvents such as tertiary butanol, methanol, and acetic acid can be used in the present invention. In the copolymerization reaction of the present invention, conditions and operations other than the above-mentioned reaction conditions are not particularly limited and may be adopted over a wide range.

For example, the optimum copolymerization reaction temperature can be selected depending on the type of polymerization initiation source, the presence or absence of an inert organic medium, the reaction molar ratio, etc.; however, normally, too high a temperature or too low a spear point is not suitable for industrial implementation. Therefore, the temperature is selected from about 20 to 90°C, preferably about 30 to 80°C. Therefore, in the present invention, it is desirable to select a polymerization initiation source that exhibits high activity at the above-mentioned suitable reaction temperature. For example, it is possible to use ionizing radiation that is highly active even at room temperature or lower, but it is usually more advantageous to use an azo compound or a peroxy compound for industrial implementation. The polymerization initiation source suitably employed in the present invention is
Azo compounds such as azobisisobutyronitrile that exhibit high activity at about 0 to 90°C, acyl peroxides such as benzoyl peroxide and lauroyl peroxide,
Peroxy ester compounds such as t-butyl peroxy isobutyrate and t-butyl peroxy pivalate, peroxy dicarbonates such as diisopropyl peroxy dicarbonate and di-12-ethylhexyl peroxy dicarbonate, dipentafluoropropionyl peroxy oxide, fluorine-containing initiators such as ditetrafluoropropionyl peroxide, and the like. In addition, various conventionally known or well-known oil-soluble peroxy compounds may also be advantageously employed. In the present invention, the concentration of the polymerization initiator is about 0.001 to 3% by weight, preferably about 0.003 to 1% by weight based on the total monomers.

By lowering the initiator concentration, it is possible to increase the molecular weight of the resulting copolymer and maintain a high ion exchange capacity. If the initiator concentration is too high, the tendency to decrease the molecular weight increases, which is disadvantageous to the production of high ion exchange capacity, high molecular weight copolymers. The copolymerization reaction of the present invention is usually carried out as follows.

That is, a carboxylic acid type functional monomer, a polymerization initiator, and optionally an inert organic solvent are charged into a pressure-resistant reaction vessel, and after sufficient degassing, the temperature is set at a predetermined temperature, and a fluorinated olefin is introduced to a predetermined pressure. Let the reaction take place. After the reaction is completed, unreacted fluorinated olefin is purged, and the copolymer slurry is precipitated in hexane or the like to recover the copolymer.
Therefore, in the present invention, it is preferable to control the concentration of the produced copolymer to 30% by weight or less, preferably 25% by weight or less. If the concentration is too high, problems such as increased stirring load, difficulty in heat removal, and poor absorption of fluorinated olefin gas will occur. The fluoropolymer of the present invention can be formed into a film by any appropriate means. For example, if necessary, a functional group is converted into a carboxylic acid group by hydrolysis, but the hydrolysis treatment can be performed either before or after film formation. It is usually preferable to perform hydrolysis treatment after film formation. Various methods can be used for forming the film, and known methods such as heating melt molding, dissolving in a suitable liquid and casting molding can be used as appropriate. Since the ion exchange membrane made from the fluoropolymer of the present invention has various excellent performances, it can be widely adopted in various fields, purposes, and uses.

For example, it is suitably used in fields where corrosion resistance is particularly required, such as in diffusion dialysis, electrolytic reduction, and as diaphragms in fuel cells.
In particular, when used as a cation-selective diaphragm for alkaline electrolysis, it can exhibit high performance that cannot be obtained with conventional 7-exchange membranes. For example, an anode and a cathode are separated using a cation exchange resin membrane made of the fluoropolymer of the present invention to form an anode chamber and a cathode chamber, and an alkali chloride aqueous solution is supplied to the anode chamber for electrolysis. Even in the case of a so-called two-chamber type tank in which alkali hydroxide is obtained from the cathode chamber, 5 to 50 A/
By electrolyzing at a current density of DTrl, sodium hydroxide with a high concentration of 40% or more can be stably produced over a long period of time with a high current efficiency of 90% or more. Furthermore, electrolysis is possible at low sliding voltages of 4.5 volts or less. Next, embodiments of the present invention will be explained in more detail.
It goes without saying that the present invention is not limited to the above description.

Incidentally, the ion exchange capacity in the following examples was determined as follows. That is, an H-type cation exchange resin membrane is
Nf) The product was left in HCl at 60° C. for 5 hours to completely convert to H-form, and the product was thoroughly washed with water so that no HCl remained.
After that, 0.5y of this H-type film was diluted with 0.1N NaOH.
It was left standing at room temperature for 2 days in a solution prepared by adding 25 d of water to 25 ml. The membrane was then removed and the NaOI in solution
V) is determined by back titration with 0.1N HCl. Example 1 In a stainless steel pressure-resistant reaction vessel with a content type of 100 d, 100
Charge f methyl perfluoro-5-oxa-6-hepetenoate and 10rf19 azobisisobutyronitrile.

After sufficient degassing with liquid nitrogen, the system is heated to 70°C. Next, add 21k9 of tetrafluoroethylene from the gas inlet.
/Cd and start the reaction. Continuous introduction of tetrafluoroethylene increases the copolymerization reaction pressure to 211<f! /Cd, and the copolymerization reaction was carried out for 6.1 hours. The resulting copolymer slurry had a copolymer concentration of 16.3% by weight, and after adding sufficient hexane to the slurry, the copolymer was recovered by filtration. As a result, 18.0f7
A white copolymer was obtained. The copolymer is TQ235
By press molding at 240°C and then hydrolyzing, an ion exchange membrane with an ion exchange capacity of 1.38 meq/y-polymer was obtained. A two-chamber electrolytic cell was formed by separating an anode and a cathode using a cation-exchange resin membrane that bursts.

A rhodium-coated titanium electrode was used as the anode, and stainless steel was used as the cathode. The distance between the two electrodes was 2.2 cm, and the effective area of the diaphragm was 25 Cd. Salt was electrolyzed under the following conditions. 4N saline solution in the anode chamber, 8N in the cathode chamber
4N saline solution was supplied to the anode chamber at 150 CC/hour, and 0.1N sodium chloride was supplied to the cathode chamber at a current density of 20 A/d and a liquid temperature of 92°C.
, electrolysis was performed using an anolyte of PH3. While the salt solution overflowed from the anode chamber, the hydrolytic soda solution overflowing from the cathode chamber was collected, and the current efficiency was determined from the hydrolytic soda produced. As a result, 14N force soda was obtained with a current efficiency of 93%. The sliding voltage was 4.1 volts, indicating stable performance over a long period of time. Example 2 internal volume 500
CF2 = 5007 in a stainless steel pressure-resistant reaction vessel of m1
Charge CFO(CF2)3C00CH and 50W9 azobisbutyronitrile.

After sufficient degassing, 70'CVC was carried out, and 19% of tetrafluoroethylene was
．． The reaction was started by charging up to 31<g/Cd. During the reaction, tetrafluoroethylene was introduced and the pressure was adjusted to 19.31<9/C.
It was held at d. After 6.5 hours 87.57 polymers were obtained.

Polymer concentration was 16.0% by weight. The copolymer has a TQ of 210°C, and is press-molded at 210°C and hydrolyzed to have a thickness of 300μ and an ion exchange capacity of 1.
An ion exchange membrane of 51 meq/f-polymer was provided.
When electrolysis was carried out using the ion exchange membrane under the same conditions as in Example 1, 14N of sodium hydroxide was applied with a current efficiency of 92% and a sliding voltage of 3.7 volts. Example 3 CF2 = 72V in a 100m1 stainless steel reaction vessel
Charge CFO(CF2)3C00CH3, 221 trichlorotrifluoroethane, and 190~ azobisisobutyronitrile.

Tetrafluoroethylene was charged to 20 kg/Cwt at 70°C to start the reaction. During the reaction, tetrafluoroethylene is introduced and the reaction pressure is maintained at 20 kg/Cd. 18 in 3 hours
．． A 2V copolymer was obtained. The copolymer has TQ=22
0° C., giving a cation exchange membrane with an ion exchange capacity of 1.20 meq/V to polymer. The ion exchange membrane is
A 14N force soda was applied with a current efficiency of 93% and a sliding voltage of 4.3 volts. Charge azobisisobutyronitrile from Example 4.

19.5kg/C of tetrafluoroethylene at 70℃ after degassing
The preparation reaction was carried out until wL. During the reaction, tetrafluoroethylene was continuously introduced and the pressure was maintained at 19.5 kg/Cwt. After 6.8 hours, a 17.6V copolymer was obtained. The copolymer had a TQ of 190°C, and was press-molded and hydrolyzed at 190°C to provide a cation exchange membrane with a thickness of 300μ and an ion exchange capacity of 1.31 meq/1-polymer.

The ion exchange membrane delivered 14N of sodium hydroxide with a current efficiency of 93% and a sliding voltage of 4.1 volts. Example 5 100V CF2=CFO (
CF2)4C00CH3 and 40 to 40% azobisisobutyronitrile were charged, and the reaction was carried out at 70° C. while maintaining the reaction pressure of tetrafluoroethylene at 15.8 k9/CwL.

After 11 hours, a 13y copolymer was obtained. The TQ of this copolymer is 185°C, and by press molding at 190°C and hydrolyzing it, it has an ion exchange capacity of 1 at a thickness of 300μ.
．． A cation exchange membrane of 64 meq/V-polymer was provided. The ion exchange membrane delivered 14N of sodium hydroxide with a current efficiency of 91% and a sliding voltage of 3.6 volts.

Example 6 100V CF2=CFO(
Charge CF2)3C00CH3 and 80 ~ t-butylperoxyisobutyrate.

After degassing, a mixed gas of tetrafluoroethylene and ethylene was charged to 19.0k9/CTi at 70°C to carry out a reaction. During the reaction, tetrafluoroethylene/ethylene mixed gas (molar ratio 90/10) was introduced into the system to increase the polymerization pressure to 19.0.
kg/Cwt.

After 4.0 hours, a 16.5V copolymer was obtained. The TQ of the copolymer is 205°C, and it is press-molded at 210°C to have a thickness of 300μ and an ion exchange capacity of 1.62 meq/V-.
A polymer cation exchange membrane was obtained. The ion exchange membrane has 4
0 wt % sodium hydroxide was applied with a current efficiency of 91% and a sliding voltage of 3.6 volts. Comparative Example 1 10y of CF2 = in a 100m1 stainless steel reaction vessel
Charge CFO(CF2)3C00CH3, 90V trichlorotrifluoroethane and 190V azobisisobutyronitrile.

After degassing, add 5k9/Cwl of tetrafluoroethylene at 70°C.
Prepare until the end and let the reaction occur. Reaction pressure 5kg/Cw
When the reaction was carried out for 20 hours while maintaining the temperature at A copolymer of IV was obtained. The TQ of the copolymer was 80 DEG C., and although an ion exchange resin with an ion exchange capacity of 1.20 meq/1-polymer was obtained by hydrolysis, it was not possible to obtain a self-supporting film. Comparative example
2 8y of CF2=C in a 100m1 stainless steel reaction vessel
Charge FO(CF2)3C00CH3, 92y trichlorotrifluoroethane, and 190~ azobisisobutyronitrile.

Claims (1)

[Scope of Claims] 1. A fluorinated ethylenically unsaturated monomer and a polymerizable functional monomer containing a carboxylic acid group or a functional group convertible to a carboxylic acid group are combined under the action of a polymerization initiation source. In the method for producing an exchange group-containing fluoropolymer, which comprises copolymerizing the functional monomer to produce a copolymer having a functional monomer content of 1 to 50 mol %, an inert organic The copolymerization reaction is carried out at a copolymerization reaction pressure of 6 kg/cm^2 or more with a proportion of 0 to 10 moles of solvent, and the ion exchange capacity is 0.5 to 4 mm when T_Q as defined in the text is 150°C or more. A method for producing an ion exchange group-containing fluoropolymer, the method comprising producing a copolymer of equivalent weight/gram dry resin. 2 As a functional monomer, there are general formulas▲mathematical formulas, chemical formulas, tables, etc.▼ (However, in the formula, l is 0 to 3, m is 0 to 1, and n is 0 to 12.
is an integer, X is a fluorine atom or -CF_3,
Y and Y' are a fluorine atom or a perfluoroalkyl group having 1 to 10 carbon atoms, and A is -CN, -COF, -COO
H, -COOR_1, -COOM or -COONR_2
R_3, R_1 is an alkyl group having 1 to 10 carbon atoms,
Claim 1 using a fluorovinyl compound represented by (R_2, R_3 are hydrogen atoms or R_1, M is an alkali metal or a quaternary ammonium group)
Manufacturing method described in section. 3 General formula C as a fluorinated ethylenically unsaturated monomer
The method according to claim 1, which uses a fluorinated olefin compound represented by F_2=CZZ' (where Z and Z' are a fluorine atom, a chlorine atom, a hydrogen atom, or -CF_3). 4 As a functional monomer, there are general formulas ▲ mathematical formulas, chemical formulas, tables, etc. COF or -COOR_1,
The manufacturing method according to claim 2, which uses a fluorovinyl compound represented by R_1 is a lower alkyl group. 5. The production method according to claim 3, wherein tetrafluoroethylene is used as the fluorinated ethylenically unsaturated monomer. 6. The manufacturing method according to claim 1, which is carried out at a copolymerization reaction temperature of 20 to 90°C. 7. The production method according to claim 1, wherein the copolymerization reaction is carried out by controlling the copolymer concentration in the produced copolymer slurry to 30% by weight or less. 8. The production method according to claim 1, which is carried out by a bulk polymerization method without using an inert organic solvent. 9. Claim 1 in which a solvent consisting of a fluorinated or fluorinated chlorinated hydrocarbon having 1 to 4 carbon atoms is used as an inert organic solvent in an amount of 5 mol or less per 1 mol of the functional monomer. Manufacturing method described. 10. The production method according to claim 9, wherein trichlorotrifluoroethane is used as the inert organic solvent.