JPS60110711A - Production of graft-polymerized membrane - Google Patents

Abstract

PURPOSE:To facilitate the formation of a graft-polymerized membrane useful as an intermediate for the production of a variety of diaphragms used in electrolysis of salt, fuel cells, etc., by irradiating an inert polymer film with an ionizing radiation and contacting the irradiated film with alpha,beta,beta-trifluorostyrene. CONSTITUTION:An inert polymer film (e.g., polyethylene film or polytetrafluoroethylene film) is irradiated with an ionizing radiation (e.g., electron beams) at a dose of about 1-30Mrad. The obtained film is immersed in a solution of alpha,beta,beta-trifluorostyrene (TFS) or coated with TFS to effect a reaction therebetween at about 10-90 deg.C for about 1-50hr. The obtained graft-polymerized membrane can have desired properties by introducing desired substituents into the benzene ring of TFS as a graft chain, for example, cation exchange membrane by introduction of sulfonic acid groups, anion exchange membrane by introduction of amino groups, and neutral membrane by introduction of hydroxyl groups.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides α-, β-, β-
The present invention relates to a method for producing a kraft polymer film comprising an inert polymer film having α,p,β-trifluorostyrene as a graft chain, which is an intermediate useful in producing a membrane having trifluorostyrene as a graft chain.

Sulfonated α, β, β-trifluorostyrene and below, α
, β, β-trifluorostyrene is called rTFsJ)
A cation exchange membrane consisting of an inert polymer film having as a graft chain is known (Japanese Patent Application Laid-Open No. 51-8988
No. 1), the cation exchange membrane is used for salt electrolysis and fuel cells. This cation exchange membrane is manufactured by graft polymerizing TFS onto an inert polymer film and then sulfonating the grafted film.

The present inventors investigated the use of a graft membrane in which the benzene ring is not substituted, which is obtained by graft polymerizing TF-8 onto an inert polymer film. , or as a cation exchange membrane by introducing a phosphate group, as an anion exchange membrane by introducing an amino group, or as a neutral membrane by introducing a hydroxyl group. We found out that it can be used.

Traditionally, kraft polymer membranes are made by graft-polymerizing TFS onto an inert polymer film.
The film is immersed in or brought into contact with an inert organic solvent solution, irradiated with Co, etc., and then TFS is grafted and polymerized, and the grafted film is then sulfonated. However, this method is produced by sulfonating the grafted film. In order to produce a cation exchange membrane with a grafting rate of
It has to be continued for 40 hours, which is low productivity and economical, and the TFS is also irradiated with radiation.
Various drawbacks have been pointed out, such as homopolymerization of itself, reduction in grafting rate, and deterioration of TFS.

In view of the usefulness of the above-mentioned graft polymer film, the present inventors investigated various economical manufacturing methods that do not cause TFS homopolymerization or deterioration, and found that the irradiation time is short and that TFS does not undergo homopolymerization or deterioration. The above-mentioned cation exchange membrane can be efficiently produced by irradiating with ionizing radiation to generate radicals, and immersing or contacting the film in which the radicals have been generated in a solution of TFS or Hiroso to cause graft polymerization. He discovered the scales.

That is, the present invention involves irradiating the inert polymer film with ionizing radiation when producing a film made of an inert polymer film having α, β, β-trifluorosulfur styrene chains, and discharging the irradiated film. α,β,β-trifluorostyrene.

This is a method for producing a kraft polymer membrane in which graft polymerization is carried out by immersion in or contact with the solution.

The inert polymer film used in the present invention may be made of any of hydrocarbon polymers, fluorinated hydrocarbon polymers, perfluoro hydrocarbon polymers, etc.
It may be a homopolymer or a copolymer, for example, polyethylene-polytetrafluoroethylene copolymer film, polychlorotrifluoroethylene film,
Polyhynylidene fluoride film, polyvinyl fluoride film, tetrafluoroethylene-hexafluoropropylene copolymer film, tetrafluoroethylene-ethylene copolymer film, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer film, chlorotrifluoride film A fluoroethylene-ethylene copolymer film is selected. Further, these films may have fine pores.

The radiation irradiated to this inert polymer film may be any radiation that generates radicals in the film, and various ionizing radiations can be used. The dose of ionizing radiation to be irradiated varies depending on the material of the inert polymer film, but is preferably 1 to 30 Mrad. Irradiation amount is I
If it is less than Mrad, the graft polymerization will not progress sufficiently, and if it exceeds 30 Mrad, the membrane function will deteriorate, which is not preferable. Irradiation can be performed in air, in an oxygen atmosphere, or in a nitrogen atmosphere. The radicals generated on the irradiated film are 0 in an inert gas atmosphere.
It has a lifespan of about 2 weeks at 10°C, about 1 week at 10°C, and 2 to 3 days at room temperature, and is convenient because it can be transported to another location after irradiation and undergo graft polymerization as described below.

Next, graft polymerization of TFS onto the irradiated film is performed. Chloroform, methylene chloride, carbon tetrachloride, 1,1
, 2.2-tetrachloroethane, 1,1.2-)lichlorotrifluoroethane, benzene, etc., or by immersing the irradiated film in TFS that is not dissolved in a solvent. It is brought into contact by coating on an irradiated film, and reacted at a reaction temperature of 10 to 90°C and a reaction time of 1 to 50 hours. In this case, there is no need to add any other catalyst or the like, and the reaction proceeds simply by immersing in TFS and bringing it into contact, and a graft polymerized membrane is produced with a grafting ratio of 10 to 50%.

This kraft polymer membrane has no special uses in itself, but it can be used to replace benzene rings with sulfonic acid groups, carboxylic acid groups, or phosphoric acid groups, and to replace cation exchange membranes with amino groups. A neutral membrane can be produced by substituting a Hj5 ion exchange membrane with hydroxyl groups. Next, substitution of the benzene ring in the kraft polymer membrane produced as described above will be explained using the introduction of a sulfonic acid group as an example.

As the sulfonating agent, chlorosulfonic acid, fluorosulfonic acid, concentrated sulfuric acid, sulfuric anhydride, etc. can be used, but since concentrated sulfuric acid has a low sulfonation rate and sulfuric anhydride is difficult to handle, chlorosulfonic acid or sulfuric anhydride can be used. Preference is given to using fluorosulfonic acid. The graft membrane is immersed in a mixed solution of a sulfonating agent, carbon tetrachloride, chloroform, methylene chloride, etc., and reacted at 40 to 150°C for 10 to 100 minutes.Then, the graft membrane is placed in an IN-KOH aqueous solution and heated at 90°C. for 1 to 2 hours to convert the sulfonate form into a salt form. A sulfonic acid film having a sulfonation rate of 40 to 100 cm and a film resistance of 0.9 to 5 Ωecffl is obtained.

D
Physical properties were compared with Nafion (registered trademark) 120 manufactured by U Pant. The results are shown in Table 1.

Table 1 (c) 0.5N/1.0 NKCl From Table 1, among the cation exchange membranes, the membrane whose inert polymer film is made of a fluorine-containing polymer is a membrane made of a perfluorocarbon polymer manufactured by DuPont. Nafion120
It can be seen that the performance is almost the same.

In addition, the following cation exchange membranes are used for water electrolysis, salt electrolysis, mirabilite electrolysis, fuel cells, redox flow batteries, amino acid soda electrolysis, high-temperature electrodialysis, zinc-
It can be used as various diaphragms for halogen type batteries and the like.

The present invention involves irradiating an inert polymer film with ionizing radiation to generate radicals in the film, and then
TFjS is not irradiated with radiation, so polymerization or deterioration of TFs does not occur, and under radiation irradiation,
Since TFS is not graft-polymerized onto an inert polymer film, the radiation irradiation time is short and the amount of radiation consumed is low, making it an economical and safe method.

Examples of the present invention are described below, but the present invention is not limited to these Examples.

EXAMPLE A low-density polyethylene film having a thickness of 100 μm was irradiated with 10 Mrad under nitrogen atmosphere using a resonant transformer type electron beam accelerator under irradiation conditions of 2 MV and 1 mA. This irradiated polyethylene film was then placed in a reactor for 10-"
After degassing under wHf reduced pressure, α, β, β-trifluorostyrene from which dissolved oxygen had been previously removed by freeze-degassing was injected into the reactor, and the irradiated polyethylene film was
, β, immersed in β-trifluorostyrene,
The reaction was allowed to proceed at room temperature for 20 hours. After the reaction, the grafted film was taken out from the container and washed with n-hexane.
Dry. The graft ratio of the graft polymerized membrane thus obtained was 23%.

This graft polymerized membrane was immersed in a solution consisting of 30 parts of chlorosulfonic acid and 70 parts of carbon tetrachloride at 40° C. for 40 minutes to effect sulfonation. After the reaction, the graft membrane was taken out from the container and washed with carbon tetrachloride to remove excess chlorosulfonic acid. The sulfonation rate of the resulting sulfonated graft polymer membrane was 95.

This membrane was immersed in an INKOH solution at 90° C. for 2 hours to cause hydrolysis. The ion exchange capacity of the graft polymerized membrane thus obtained was 1.5 meq/dry membrane.

This graft polymerized film was heated at 20°C in 0.6 NKCJ at IK.
The electrical resistance measured with alternating current of I (Z is 1.40・d and h
'), the transference number measured at 0.5NK (J/1.ONKC) was 0.90.

Additionally, the graft polymerized membrane was treated with 3% Mohr salt containing 4 ppm.
When the film was immersed in an aqueous H2O2 solution at 70°C for 24 hours, the weight loss rate of the film was 15%.

Example 2 A graft polymerized membrane was obtained in exactly the same manner as in Example 1, except that a polyvinylidene full second film having a thickness of 100 μm was used. At this time, the grafting rate was 20%, the sulfonation rate was 60%, and the ion exchange capacity was 0.6 meq/dry membrane.

This graft polymerized membrane was incubated at 20°C in 0.6NKCl at IK.
The electrical resistance measured at Hz alternating current is 3.20 kd,
The transport number measured by 0.5NKC1/LONMCI is 0.9
It was 3.

In addition, the graft polymerized membrane was treated with 3-H containing 4 ppm of Mohr's salt.
! When immersed in 02 aqueous solution at 70°C for 24 hours,
The weight reduction rate of the graft polymerized membrane was 10q6.

Example 3 A 100 micron thick tetrafluoroethylene-ethylene copolymer film was irradiated with 10 Mrad in the same manner as in Example 1. Next, put this irradiated film into a reactor and
After degassing under reduced pressure and removing dissolved oxygen in advance by freeze-degassing, add a β,β-trifluorostyrene solution (α,β,β-trifluorostyrene 50 parts, 1,1.2-) ') 50 parts of chloro-trifluoroethane) and irradiated film force, α
, β, β-trifluorostyrene immersed in 5
Graft polymerization was carried out at 0°C for 20 hours. After the reaction, the grafted film was taken out from the container, washed with n-hexane, unreacted monomers were extracted and removed, and then dried. The graft ratio of the graft polymerized membrane thus obtained was 21%.

Figure 1 shows the surface infrared absorption spectrum of the tetrafluoroethylene-ethylene copolymer'; This is an infrared absorption spectrum.

In Figure 2, the absorption of 1720 and 1640 crn-'' is
The absorption at 690 crn indicates the double bond of the benzene ring, and the absorption at 690 crn-' indicates monosubstitution of the benzene ring, and both spectra confirm that TFS is graft polymerized to the tetrafluoroethylene-ethylene copolymer film. did.

This graft polymerized membrane was mixed with 30 parts of chlorosulfonic acid, i.
i, 13 in a solution consisting of 2,2-tetrachloroethane
It was immersed at 5° C. for 40 minutes to effect sulfonation. After the reaction, the graft polymerized membrane was taken out from the container and washed with carbon tetrachloride to remove excess chlorosulfonic acid. The sulfonation rate of the graft polymerized membrane thus obtained was 90%.

This graft polymerized membrane was placed in INKOH solution at 90°C for 2 hours.
It was soaked for a period of time and hydrolyzed. The ion exchange capacity of the graft membrane thus obtained was 1.0 rneq/
It was a y-dry film.

j (D Kura 7) Polymer film total 20 in 0.6 NKCl
The electrical resistance measured with AC of C1I KII is 2.1Ω
・At d #:>, O,5NKCJ/1.0NKC The measured transference number was 0,92h. Also, this film was immersed in a BS% fake aqueous solution containing 4 ppm of Mohr's salt at 70°C for 24 hours. Upon treatment, the weight loss rate of the film was 3%.

Example 4 A tetrafluoroethylene-ethylene copolymer film having a thickness of 100 μm was subjected to graft polymerization and sulfonation in exactly the same manner as in Example 3 to obtain a graft polymer film. At this time, the galley foot rate was 16%, the sulfonation rate was 80%, and 1.
It was 0.7 meq/P-dry membrane.

and tD graph) M gold film t0. aNKcl at 20°C, I
The electrical resistance measured at KHz alternating current is 3.5Ω・d, and the transference number measured is 0, 5NKC//1.0NKC.
．． 93 ``t' was there.

In addition, this graft polymerized membrane was mixed with 3 containing 4 ppm of Mohr's salt.
% H*O* aqueous solution at 70° C. for 24 hours, the weight loss rate of the graft polymerized membrane was 3 cm).

Example 5 5! on a polynato 2 fluoroethylene film with a thickness of 100μ. ! Graft polymerization and sulfonation were carried out in exactly the same manner as in Example 3 to obtain a graft polymerized membrane. At this time, the grafting rate was 18%, the sulfonation rate was 6°, and the ion exchange capacity was 0.6 meq/f-dry membrane.

This graft polymerized film was heated at 0.6 N K (in J at 20°C, I
The electrical resistance measured with an alternating current of KHz was 4.00·d, and the transference number measured was 0.5NK (J/1.0NKC7).

In addition, this graft polymerized membrane contains 4 Ppm of Mohr's salt.
% HzO* aqueous solution at 70° C. for 24 hours, the weight reduction rate of the graft polymerized membrane was 1tI6 or less.

Example 6 Ruthenium black and graphite powder were mixed at a weight ratio of 1:1 on both sides of the graft polymerized film synthesized according to the method of Example 4, and this mixed powder was heated at 350°C using polytetrafluoroethylene as a binder. 126i'v/d.

It was pressed for 30 minutes. Next, graphite and polytetrafluoroethylene emulsion were mixed at a weight ratio of 8:2,
j(7) Mixture at 350°C, 130Kt/m, 30
A porous membrane having a thickness of 10oμ was obtained by hot pressing for minutes. This porous membrane was attached to one side of a graft membrane having a catalyst layer by heating and holding at 350° C. and 130 kg/m for 30 minutes to prepare a fuel cell with the porous lower side as the oxygen electrode side.

Example 7 Saturated saline was electrolyzed in an electrolytic cell with an effective current-carrying area of 1 dm using the graft polymerized membrane synthesized according to the method of Example 4.
A material coated with Ox and Ru 02 was used, and a stainless steel mesh was used as the cathode.

When saturated saline was supplied to the anode chamber and electrolysis was carried out at a current density of 30 A/dm, the current efficiency was 929 g and the cell voltage was 3.3.
30% NaOH was obtained at v.

Example 8 A three-chamber electrolyte chamber divided into an anode chamber, a central compartment, and a cathode chamber was prepared using two graft polymerized membranes synthesized according to the method of Example 4, and the anode was made of titanium mesh with T 10! r Ru
O! Ni mesh was used for the cathode, 10% S04 was used for the anode chamber, and 15% S04 was used for the central compartment.
%NazSOn and 101NaOH were supplied to the cathode chamber and electrolyzed at a current density of 20A/dm. As a result, 41I (!SOa solution, 15%
NaOH was obtained at a current efficiency of 70 cm and a cell voltage of 4.2 V.

Procedural amendment (voluntary) March 1980, Director General of the Japan Patent Office Kazuo Wakasugi 1, Indication of the case 1988 Patent M No. 218679 2, Name of the invention Method for producing graft polymerized membrane 3, Make amendments Patent applicant address 2-1-1 Toranomon, Minato-ku, Tokyo Mitsui O.S.K. Pill Name Chlorin Engineers Co., Ltd. Representative Junji Sato 4, agent (?105) Address 2-chome Toranomon, Minato-ku, Tokyo No. 1 No. 1 Mitsui O.S.K. Pill Voluntary Issue 6, “Brief Explanation of Drawings” column and drawing 7 of the BAIfm document subject to amendment,
Contents of amendment (1) On page 18 of the specification, line 11, after "obtained with." Tetrafluoroethylene-ethylene co-3 before graft polymerization
! The surface infrared absorption spectrum of the combined film, and FIG. 2 is the surface extranominal absorption spectrum of the graft polymerized film obtained by graft polymerizing TFS to the film. ” to join.

(Include the attached circular, Figures 1 and 2.

(that's all)

Claims (7)

[Claims] (1) When producing a graft membrane consisting of an inert polymer film having α, β, β-trifluorostyrene as a graft chain, the inert polymer film is irradiated with ionizing radiation, and the irradiated film is 1. A method for producing a graft polymerized membrane, which comprises graft polymerization by immersion in or contact with β,β-trifluorostyrene or a solution thereof. (2) The inert polymer film is a polyethylene film, a polytetrafluoroethylene film, a polychlorotrifluoroethylene film, a polyvinylidene fluoride film, a polyvinyl fluoride film, a tetrafluoroethylene-hexafluoropropylene co-polymer film, Tetrafluoroethylene-ethylene copolymer film, tetrafluoroethylene-propylene copolymer film, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer film, chlorotrifluoroethylene-ethylene copolymer film, chlorotrifluoroethylene-propylene A method according to claim 1, wherein the film is selected from the group consisting of copolymer films. (3) The manufacturing method according to claim (1) or (2), wherein the irradiation dose of ionizing radiation is 1 to 30 Mrad. (4) The manufacturing method according to any one of claims (1) to (3), wherein the graft polymerization temperature is 10 to 90°C. (5) The manufacturing method according to any one of claims (1) to (4), wherein the graft polymerization time is 1 to 50 hours. (6) As a solvent for α, β, β-trifluorostyrene, chloroform, methylene chloride, carbon tetrachloride, 1.1
, 2.2-tetrachloroethane, 1,1.2-)lichlorotrifluoroethane, and benzene. Manufacturing method described. (7) The method according to any one of claims (1) to (5), in which α, β, β-trifluorostyrene is graft-polymerized without using a solvent.