JPS582969B2 - Aeon Kokanjiyushimakunoseizohouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an ion exchange resin membrane, particularly a cation exchange resin membrane suitable for diaphragm electrolysis of alkali metal salts.

Conventionally, ion exchange membranes have been widely used in various fields including the chemical industry, and the most extensive use is for desalination and concentration of seawater, as well as for the desalination of underground brine.

Furthermore, in recent years, ion exchange membranes have been used for diaphragm electrolysis of common salt.

There are various properties required for these ion exchange membranes, such as low electrical resistance, high transference number,
These include mechanical strength, dimensional stability, and chemical stability.

However, the properties of these ion-exchange membranes are contradictory to each other; for example, increasing the degree of crosslinking of the model resin structure to increase the transference number increases electrical resistance, reduces mechanical strength, and makes it brittle. Increasing the thickness of the film to increase mechanical strength leads to an increase in electrical resistance.

When considering the various contradictory properties of such ion exchange membranes, it is desirable to provide the ion exchange membrane with a base material that does not have ion exchange ability and serves as a reinforcing material.

Therefore, most of the homopolymerized ion exchange membranes and heterogeneous ion exchange membranes used industrially today are polymers that do not have any ion exchange groups bonded to them and do not participate in ion permeation. Compounds and the like are added as reinforcing materials.

That is, woven fabrics, non-woven fabrics, nets, knitted fabrics, etc. are used as the base material, and the materials include polyvinyl chloride, polyolefin,
It has been proposed to use nylon-66, polyethylene terephthalate, polyvinyritene chloride, polyvinyl alcohol, polytetrafluoroethylene, asbestos, cotton, wool, and the like.

Generally, in the production of homogeneous polymerized ion exchange membranes, the above-mentioned reinforcing material contains a monomer having an ion exchange group, a monomer having a functional group suitable for introducing an ion exchange group, or a functional group that can be easily converted into an ion exchange group. It is carried out by attaching a monomer mixture consisting mainly of monomers and adding a crosslinking agent as necessary, and then polymerizing and forming it into a membrane, and then introducing ion exchange groups or converting to ion exchange groups as necessary. .

However, in the ion-exchange resin membrane obtained above, there is a problem in the adhesion between the portion having an ion-exchange group, that is, the resin portion that participates in ion permeation, and the reinforcing material that does not participate in ion permeation.

In other words, the ion-exchange resin part that allows ions to permeate undergoes extremely complex dimensional changes and expands and contracts depending on the temperature, salt concentration, resin composition, etc. in an aqueous solution, resulting in misalignment with the reinforcing material, which has little expansion and contraction, resulting in poor adhesion. This will result in defects.

For this reason, highly polar polymer compounds such as polyvinyl chloride and acrylonitrile, which are relatively easily impregnated with vinyl monomers that are one of the ion exchange resin components, are often used as reinforcing materials.

However, these polymer compounds have drawbacks in terms of heat resistance and chemical resistance, which limits the use of the resulting ion exchange membranes.

On the other hand, when a polymer compound with low polarity and heat resistance and chemical resistance, such as polyolefin, is used as a reinforcing material, the adhesion between the ion exchange resin part and the reinforcing material is poor;
Pinholes are easily formed on the membrane surface, often resulting in separation of the ion exchange resin portion and reinforcing material, or micro-cracks.

The presence of such cracks or pores in the ion exchange membrane significantly reduces the efficiency of the process when solutes are transferred.

Therefore, when using polyolefins as a reinforcing material, it is necessary to provide polarity in advance to an extent that does not impair the properties of the polyolefin, such as a halogen group, a functional group capable of initiating radical polymerization such as hydroperoxide, or a sulfonic acid group. Although improvements have been made by methods of introducing nitro groups, halosulfonic acid groups, etc., they are still not fully satisfactory.

In addition, as mentioned above, most of the uses of ion exchange membranes to date involve desalting or concentrating neutral salt solutions by electrodialysis, and the ion exchange ability is sufficient at a pH value near neutrality as an ion exchange group. What can be achieved has been used.

That is, in the cation exchange membrane, it is a sulfonic acid group,
For anion exchange membranes, it is a quaternary ammonium base.

Among these, cation exchange membranes having sulfonic acid groups generally use styrene instead of divinylbenzene because monomers such as vinyl sulfonic acid, its salts or esters, or styrene sulfonic acid, its salts or esters cannot be synthesized at low cost. It is obtained by copolymerizing with a sulfonating agent such as chlorosulfonic acid, sulfuric acid, fuming sulfuric acid, or a mixture thereof, or a complex of sulfur trioxide with dioxane, amines, etc.

Therefore, especially in the case of cation exchange membranes, the base material used as the reinforcing material is required to be resistant to the above-mentioned sulfonation reagent.

On the other hand, in recent years, as the applications of ion exchange membranes have diversified, they have been used not only for electrodialysis and electrodialysis of neutral salt solutions, but also in strong acidic and strong basic atmospheres, and cation exchange membranes have been used for salt electrolysis. One example is its use in diaphragms such as diaphragms.

In such cases, ion exchange membranes have a high pH, unlike conventional membranes.
Naturally, cation exchange groups include strongly acidic sulfonic acid groups, ion exchange groups as well as weakly acidic ion exchange groups such as carboxylic acid groups, phenolic hydroxyl groups, phosphorous acid groups, and thiol groups. Groups are also suitable for use.

In addition, high-temperature desalination using ion exchange membranes, diaphragm electrolysis, etc. are often used at temperatures above 50°C and around 100°C.
Since the cation exchange resin itself can withstand up to 120°C, the reinforcing material must also be able to withstand high temperatures.

The present inventors conducted research from the viewpoint of the adhesion between the ion exchange resin part and the reinforcing material in the ion exchange resin membrane described above, and the possibility of using it in a strong alkaline atmosphere and at high temperatures. The present invention was completed by discovering that a cation exchange resin membrane using a water-insoluble polymer compound having a hydroxyl group and having a carboxyl group in the ion exchange resin component can solve all of the above-mentioned problems.

In the present invention, a monomer mixture mainly consisting of a monomer having an ion exchange group, a monomer having a functional group suitable for introducing an ion exchange group, or a monomer having a functional group that can be easily converted into an ion exchange group is attached to a reinforcing material. When producing an ion exchange resin membrane by polymerization, one of the monomers is a vinyl monomer having at least a carboxyl group, and the carboxyl group accounts for 10% of the total ion exchange capacity of the resulting ion exchange resin membrane. or more, and 10% of the total monomer units as the reinforcing material.
This is a method for producing an ion exchange resin membrane characterized by using a water-insoluble polymer compound in which an alcoholic hydroxyl group is present in the monomer unit described above.

That is, the reinforcing material used in the present invention is a water-insoluble polymer compound having an alcoholic hydroxyl group, and in particular, having the alcoholic hydroxyl group is the reason why the reinforcing material and the ion-exchange resin part in the ion-exchange resin membrane are bonded as described below. It is extremely important to obtain good adhesion.

In addition, in order to obtain good adhesion between the reinforcing material and the ion exchange resin part, 10% of the total mo/mer unit is generally used.
It is preferable to use a polymer compound having an alcoholic hydroxyl group in the above monomer unit.

Examples of such polymeric compounds having alcoholic hydroxyl groups in 10% or more of all monomer units include polyvinyl compounds having vinyl alcohol groups and allyl alcohol groups, such as partial hydrolysates of polyvinyl acetate; Polyvinyl alcohol, hydrolyzed copolymers of vinyl acetate and vinyl chloride, and other copolymers or graft polymers of vinyl acetate and various vinyl monomers or allyl monomers that contain 10% or more of vinyl acetate. These include things that have been hydrolyzed.

Other monomers to be copolymerized or graft copolymerized include acrolein, acrylic acid, methacrylic acid, acrylonitrile, 1-acrylamido-1-deoxy-D-glycitol, allyl acetate, allyl chloride, allyl laurate, and butyl vinyl ether. , butyl vinyl sulfonate, chlorotrifluoroethylene, crotonic acid, crotonamide, diallylmelamine, diallyl phthalate, di-n-butyl itaconate, diethyl fumarate, maleic acid esters, N/N-divinylaniline, dl-ethyl-2 -methyl-2-ethyl-1
putinoate, ethyl vinyl oxalate, N-ethyl-Nl-vinyl urea, methacrylic esters, acrylic esters, hydroxymethyl crotonate, isopropenyl acetate, maleic anhydride, methacrylonitrile, methacryloxymethylpentamethyldisiloxane, Methyl allyl chloride, methyl bicyclo(2.2.1)-2-heptene-5-carboxylate, methylolcroton acid, methyl vinyl ketone,
Salts such as methylvinylsulfone, phenylvinylsulfone, sodium acrylate, styrene, triallylcyanurate, triallylisocyanurate, trichloroethylene, 3,3,3-trichloropropane, trimethylsiloxyvinyldimethylsilane, bis-trimethylsiloxy Vinylmethylsilane, tris(}trimethylsiloxy)monovinylsilane, vinylbenzoate, vinyl bromide, N-vinylrubazole, vinylchloroacetate
1-, vinylene carbonate, 1-vinyl-3-ethylurea, vinylidene chloride, vinylidene cyanide, vinylisocaproate, vinyl laurate, vinyl octadecanoate, N-vinyloxazolidinone, vinyl palmitate , vinylpyridines, N-vinylpyrrolidone, N-vinylsuccinimide, vinyl trifluoroacetate, N-vinylurethane, ethylene,
These include propylene and butene.

In particular, the material most easily used as a reinforcing material in the present invention is a polymer compound mainly composed of polyvinyl alcohol, but since fibers obtained from polyvinyl alcohol dissolve in hot water, they must be improved and improved by appropriate post-treatment. Modified 5
It is necessary to make it insoluble in hot water below 5°C.

That is, insolubilization by heat treatment, various acetalization methods, for example, monoaldehydes and dialdehydes such as formaldehyde, benzaldehyde, nonylaldehyde, glyoxal, acutelein, adipodialdehyde, etc.
Preferably, those subjected to acetalization treatment by ~80%.

Other methods include treating fibers with periodic acid to break 1,2-glycol bonds and then treating with acid, treating with acetyl sulfide, treating with crotonaldehyde and then reacting with ammonia amines, and aminoaldehyde. There are methods such as using .

There is also a method of graft polymerizing various monomers to polyvinyl alcohol fiber using radiation or a normal polymerization initiator.
For example, acrylonitrile, styrene methacrylic acid,
A method of graft polymerizing salts, esters, vinylpyridines, etc. thereof is used.

The degree of these treatments varies depending on the purpose of use.

For example, if the crosslinking is too dense or the degree of acetalization is too high, it is not desirable when making fibers, and at the same time it is disadvantageous in terms of improving the adhesion between the ion exchange resin component and the reinforcing material, which is the objective of the present invention. go.

Therefore, taking these conditions into consideration, it is preferable to carry out the treatment to a degree of acetalization of 5 to 80%.

Usually, the reinforcing material is the monofilament long fibers mentioned above,
Woven fabrics, nonwoven fabrics, nets, knitted fabrics, etc. with an open area ratio of 10 to 90% obtained from raw yarns spun from short fibers are used.

The above reinforcing materials include fibers with vinyl alcohol groups such as polyvinyl alcohol, and other heat-resistant fibers without vinyl alcohol groups such as polypropylene, acetate fibers, rayon, cupro fibers, natural fibers (vegetable fibers), and animal fibers. It may be a woven fabric, a knitted fabric, or a non-woven fabric of these by twisting or interweaving with quality fibers.

Next, the ion exchange resin component in the present invention is a monomer having an ion exchange group, a monomer having a functional group suitable for introducing an ion exchange group, or a monovinyl compound that is a monomer having a functional group that can be easily converted into an ion exchange group. A monomer mixture is used in which a radical polymerization initiator is added to a polyvinyl compound and other additives, and if necessary, a linear or fine powder polymer is dissolved or dispersed.

In the present invention, it is important to use a monomer having at least a carboxylic group as one of the above-mentioned monovinyl compounds in order to integrate and bond the reinforcing material and the ion exchange resin part, and it is important to use a monomer having at least a carboxylic group as one of the monovinyl compounds mentioned above, and also to completely form the ion exchange resin membrane. It is preferable to have carboxyl groups present in an amount of 10% or more relative to the ion exchange capacity, in order to use the ion exchange resin membrane as a diaphragm, particularly for electrolysis of alkali metal salts.

That is, the affinity between a monomer having a carboxyl group and a monomer having an alcoholic hydroxyl group is good, and in particular, when a vinyl monomer having a carboxyl group is used as one of the raw material monomers, the total ion exchange of the resulting ion exchange resin membrane is Affinity when using a water-insoluble polymer compound in which carboxyl groups are present in 10% or more of the capacity and alcoholic hydroxyl groups are present in 10% or more of the total monomer units as a reinforcing material. is extremely large, and air bubbles etc. are not included between the resin part and the reinforcing material after film formation.The occurrence of pinholes is reduced and film formation is extremely easy.

In addition, the alcoholic hydroxyl groups present in the reinforcing material and the carboxyl groups in the ion exchange resin component intertwine with each other three-dimensionally during the polymerization mold to form ester bonds, so that the reinforcing material and the resin component are integrated. An ion exchange resin membrane with good adhesiveness can be obtained.

Furthermore, since the carboxyl groups of the ion exchange resin membrane obtained in the present invention have a strong interaction with hydroxyl ions, leakage of the hydroxyl ions is small and high current efficiency can be obtained in the electrodialysis system.

Therefore, the ion exchange resin membrane of the present invention is suitable for use in an atmosphere with a pH of 7.0 or higher, and is most suitable as a diaphragm for electrolysis of alkali metal salts, for example.

In this case, it is preferable that all of the ion exchange groups in the ion exchange resin membrane are carboxyl groups, but when the carboxyl groups are present in a proportion of 10% or more of the total ion exchange capacity through various membrane forming methods, hydroxyl ions are removed. Leakage is reduced and current efficiency in the electrodialysis system is significantly increased.

Examples of the above-mentioned vinyl monomers having a carboxyl group include acrylic acid, methacrylic acid, α-phenylacrylic acid, α-monoethyl acrylic acid, α-halogenated acrylic acid, maleic acid, itaconic acid, and α-tolylacrylic acid. , α-butyl acrylic acid, vinylbenzoic acids, those in which a vinyl group and a carboxyl group are bonded to a naphthalene ring, etc. are preferably used, but one or more vinyl groups, regardless of whether they are aliphatic or aromatic, There is no restriction at all as long as an allyl group and one or more carboxyl groups are bonded and radically polymerized to give a polymer.

Among other components of the mixture that adheres to the reinforcing material together with the vinyl monomer having a carboxyl group, monovinyl monomers that can be copolymerized with the vinyl monomer having a carboxyl group include styrene, vinyltoluenes, methacrylic esters, and acrylic esters. , acrylonitrile, vinylpyridines, N-vinylpyrrolidones, vinylimidazoles, butadienes, isoprenes, chloroprenes, vinyl chloride, vinyl acetate, acrolein,
Methyl vinyl ketone, chloromethylstyrenes, monochlorostyrenes, polychlorostyrenes, α-fluorostyrene, α・β・β-trifluorostyrene, α-methylstyrene, hnylidene chloride, vinyl fluoride, vinylitene fluoride, chloro Methylstyrenes, vinylsulfonic acid and salts, esters, styrenesulfonic acid and arsenic salts, esters, allylsulfonic acid and salts, esters, vinylphosphonic acid and salts, esters, styrenephosphonic acid and salts, esters, Styrene phosphinic acid and salts, esters, vinyl phosphinic acid and salts, esters, vinylphenols and salts, esters, vinyl acetate, ethylene tetrafluoride, ethylene trifluoride, ethylvinylbenzenes, maleic esters, Itaconic acid esters, vinyl bromide, and polyvinyl compounds as crosslinking agents include 0-, m-, p-divinylbenzene and mixtures thereof, divinylpyridines, trivinylbenzenes, divinylnaphthalenes, trivinylnaphthalenes, Imprene, chloroprene, butadiene, divinylchlorobenzenes, divinylethylbenzenes, pimethallyl, biallyl, divinyl ether, divinylacetylene, divinylsulfone, 2,3-diethylptadiene, halobutadienes, and the like are used.

In addition, as a radical polymerization initiator, penzoyl peroxide, α・α-azoin butyronitrile, lauryl peroxide, tert-butyl peracetate, te
rt-butyl perbenzoate, 2,5-dimethyl (2
・5-dipenzoylperoxy)hexane, 2,5-dimethyl(2,5-dibenzoylperoxy)hexane-
3. p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, α・α′-di(tert
-butylperoxy)diisopcobylbenzene, cyclohexanone peroxide, tert-butylperoxy isopropyl carbonate, 2,5-dimethyl-3
-hexane, 2,5-dimethyl-3-hexyne, 2,5-
Diperoxyisogropyl, tert-butyl peroxylaurate, di-tert-butyl diperoxyphthalate, ruperoxy)-3,3,5-trimethylcyclohexane, methyl ethyl peroxide, methyl isobutyl ketone peroxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, di-te
rt-amyl peroxide, tert-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl 2,5-di(tert-butyl peroxy)hexane, 2,5-dimethyl 2,5-di(tert-butyl peroxy)hexane- 3. Also, the decomposition temperature is 135
Cumene has a half-life of 10 hours or more at temperatures above ℃.
Hydroperoxide, 2,5-dimethyl 2,5-dihydroperoxy hexane, 2,5-dimethyl 2,5-
Dihydroperoxyhexine-3, etc. (at least 60℃)
If the half-life is 10 hours or more at the above temperature, it can be used without any restrictions.

Furthermore, linear polymers to be dissolved or dispersed in the above mixture as necessary include styrene-butadiene copolymers, polystyrene, polyacrylic esters, chlorosulfonated polyethylene, polychloroprene, polybutadiene, polyethylene, and polypropylene. , polyvinyl halide, polyvinylidene halide, polyethylene trifluoride, polyethylene tetrafluoride, halogenated polyethylenes, halogenated propylene, chlorosulfonated polypropylene, polyvinyl chloride, polyvinylidene chloride, etc. are used.

There are no particular restrictions on the method of attaching the mixture obtained above to the reinforcing material having an alcoholic hydroxyl group.

That is, a method in which the reinforcing material is immersed in the mixed solution, deaerated, and then rolled up onto a roll with a separation sheet sandwiched between them: The separation sheet and the reinforcing material are wound up on a roll in advance, and this is directly applied to the mixed solution. A method in which the reinforcing material is continuously passed through the mixed liquid and then rolled up into a roll with a separating sheet sandwiched between them; Or a method in which the reinforcing material is continuously passed through the mixed liquid and then rolled up with a separation sheet in between; A method is used in which a reinforcing material is sandwiched between the reinforcing materials and a mixed solution is poured between the reinforcing materials and degassed.

Next, polymerization is carried out at a temperature at which the radical polymerization initiator is decomposed and the vinyl monomer is polymerized to form a polymer film, and the polymerization may be carried out under conditions that will increase the degree of polymerization as much as possible.

The obtained polymer membrane is hydrolyzed by immersion in an alkaline aqueous solution or an alkaline alcohol solution, or heated in an alkaline aqueous solution, an alkaline alcohol solution, or an acid aqueous solution to undergo cation exchange. It can be a resin film.

As described above, the ion exchange resin membrane of the present invention obtained in the above manner is extremely stable because the resin part and the reinforcing material are almost integrated, exhibits extremely excellent electrochemical properties, and can be used at high temperatures and in an alkaline atmosphere. Even when used, its properties change very little over time.

The content of the present invention will be explained in more detail in the following examples, but the present invention is not limited to the following examples.

In addition, in the examples, the electrical resistance of the film was 0.5N-Na.
Measured in OH at 25.0°C.

The diffusion constant is 4. ON-NaOH (250cc) and pure water (
The amount of NaOHO diffused into pure water was determined using a two-chamber diffusion cell using a 170cc).

The liquids in both chambers were vigorously stirred at a speed of 1500±10 Orpm to prevent the growth of a diffusion film at the membrane-liquid interface.

Also, the amount of water permeation under pressure through the membrane is 6.2 cm2.
The membrane was placed on a stainless steel perforated plate with an effective area of , and the amount of pure water permeated was determined under nitrogen pressure.

Furthermore, the electrolytic experiment used a three-chamber electrolytic cell with an effective membrane area of 0.5 dm2.

The anode used was a metal titanium coated with ruthenium oxide and titanium oxide, and the cathode was a nickel mesh.

A water-permeable neutral diaphragm was placed in contact with the anode, and a cation exchange resin membrane of the present invention was placed in contact with the cathode.

Water pressure was applied to the intermediate chamber to supply saturated salt water, and the salt water was supplied to the anode chamber through the porous neutral membrane.

In addition, a certain amount of pure water was supplied to the caustic soda produced at the cathode to obtain a certain concentration of caustic soda.

Note that the current density was 20 A/dm2 and the temperature was 70°C.

To measure the ion exchange capacity, a certain weight of membrane is measured in 6. ON-Na
It was immersed in OH for 24 hours to completely convert it into sodium form, washed with water, and immersed in an excess of N/101 H2SO4 for 16 hours.

Next, this liquid was back titrated with N/10-NaOH to determine the exchange capacity from the amount of H2S04 exchanged with the ion exchange groups of the membrane.

The membrane used to measure the exchange capacity was dried under reduced pressure at 60° C. to determine its dry weight.

The wet weight was determined and subtracted to determine the moisture content per dry weight, and the exchange capacity per dry weight was also determined.

Example 1 30 denier fibers were made vertically as a reinforcing material for an ion exchange membrane.
A polyvinyl alcohol cloth with 50 strands per inch was used on both sides.

This polyvinyl alcohol cloth had a degree of acetalization by formalin of 20%.

In addition, 20 parts of styrene, 10 parts of divinylbenzene with a purity of 55%, and 20 parts of methacrylic acid are used as ion exchange resin components.
20 parts of stearyl methacrylate was added thereto, 20 parts of styrene-butadiene copolymer rubber was uniformly dissolved therein, and 1% of penzoyl peroxide was added based on the total monomers to prepare a paste-like mixture.

The above paste-like mixture was applied uniformly to a polyvinyl alcohol cloth while degassing, both sides were covered with cellophane, and heated and polymerized at 80°C for 24 hours to obtain a film-like polymer, which was then soaked in 4N-NaOH. A cation exchange resin membrane was manufactured by soaking for 24 hours.

All ion exchange groups in this ion exchange membrane are -COOH,
Ion exchange capacity is 2.40meq/g. It was a dry film.

About the obtained cation exchange resin membrane, 0.5N-NaO
As a result of measuring the electrical resistance in H, it was 12Ω-cm at 25°C.
It was 2.

Also, the diffusion constant of NaOH is 2. IX10-9cm2/s
ec, and as a result of measuring the amount of water permeation under a pressure of 10 kg/cm2, it was 2X10-10 CC/k9·sec.

On the other hand, a cation exchange resin membrane was produced in exactly the same manner as above except that the same mesh reinforcing material made of 30 denier long fiber yarn made of polypropylene was used instead of the polyvinyl alcohol cloth.

The electrical resistance of the obtained cation exchange resin membrane was 10
．． 2Ω-cm-2, the diffusion constant of NaOH is 6.2X10
The amount of water permeation under pressure of -8cm2/sec and 10kg/cm was 5.3XIO-8cc/kg·sec.

Next, the cation exchange resin membranes manufactured using the above polyvinyl alcohol cloth and polypropylene cloth as reinforcing materials were each subjected to three-chamber electrolysis of saturated saline, and the results at the start of electrolysis and after 3 months of electrolysis were compared. The results are shown in Table 1.

In Table 1, NaOH concentration (N) refers to the concentration of NaOH obtained in the cathode chamber, and NaCl in NaOH refers to the concentration of NaOH obtained in the cathode chamber or in the converted concentration of NaOH. NaCl concentration is shown.

The same meaning applies to the following examples.

Example 2 As a reinforcing material for the ion exchange membrane, a cloth in which 240 denier polyvinyl alcohol long fibers were implanted with 60 lengthwise and widthwise 57 fibers per inch was used.

Note that this polyvinyl alcohol fabric had been heat treated and was insoluble in hot water up to 70°C.

In addition, 2 parts of lauroyl peroxide was dissolved based on the total monomers in a mixture consisting of 15 parts of methacrylic acid, 20 parts of styrene, 20 parts of vinylsulfonic acid n-butyl ester, and 20 parts of n-butyl methacrylate as ion exchange resin components. Then, 10 parts of Nihypalon #48 (chlorosulfonated polyethylene, manufactured by DuPont) was dissolved in the total monomer to make it viscous.

A polyvinyl alcohol cloth was immersed in the above monomer mixture, deaerated, taken out, both sides covered with cellophane, heated and polymerized at 100°C for 24 hours to obtain a polymer membrane, and then 8% KOH A cation exchange resin membrane was produced by immersing the membrane in the liquid and refluxing it to hydrolyze the vinyl sulfonic acid ester.

One COOH in the obtained cation exchange resin membrane was 59% of the total ion exchange capacity.

About the obtained cation exchange resin membrane, 0.5N-NaO
The electrical resistance measured in H is 8Ω cm2 at 25°C, Na
The diffusion constant of OH is 1.2X10-8cm2/sec, 1
Water permeability under pressure of 0 kg/cm2 is 1.3 x 10
-8 CC/kg·sec.

Further, as a result of subjecting this cation exchange resin membrane to electrolysis of saturated saline using a three-chamber electrolysis method, 4. ON-NaOH 9
Obtained with a current efficiency of 5%, N converted to 48% NaOH
The amount of NaCl in aOH was 80 ppm.

Furthermore, as a result of carrying out electrolysis continuously for 3 months, the concentration of NaOH after 3 months was 3.8N, the current efficiency was 94.5%, and the amount of NaCl in NaOH remained unchanged at 80 ppm.

Example 3 A 1.6 mesh fabric made from a polymer compound having vinyl alcohol groups by hydrolyzing a copolymer obtained by copolymerizing ethylene and vinyl acetate in a KOH-methanol solution as a reinforcing material for an ion exchange membrane. A net was used.

In addition, 3 parts of styrene-butadiene copolymer rubber was added to a mixture of 10 parts of acrylic acid, 10 parts of methacrylic acid, 35 parts of styrene, 10 parts of divinylbenzene with a purity of 55%, and 0.7 parts of penzoyl peroxide as ion exchange resin components.
A product was prepared in which part of the solution was dissolved and two parts of a fine spherical polyethylene powder having a particle size of about 10 microns was dispersed.

This was applied uniformly to the above-mentioned mesh, both sides covered with cellophane, and heated and polymerized at 80°C to form a polymer film.
4. A cation exchange resin membrane was manufactured by immersion treatment in ON-NaOH.

About the obtained cation exchange resin membrane, 0.5N-NaO
When the electrical resistance was measured in H, it was 8.5Ω-cm2, N
The diffusion constant of aOH is 1.8X10-9Cm2/sec,
Further, when the water permeability was measured at a water pressure of 10 kg/cm2, it was 3.8 x 10-9'cc/kg.Sec.

Example 4 Polyparahydroxystyrene was dissolved in an aqueous solution of caustic soda, paraformaldehyde and iminodiacetic acid were added thereto and heated, and iminodiacetic acid was bonded to polyparahydroxystyrene to form a compound having a carboxylic acid and a tertiary amine. An amphoteric polyelectrolyte was obtained.

This was dissolved in an alkaline aqueous solution at a weight ratio of 2:1 to polyvinyl alcohol, and then cast on a polyvinyl alcohol cloth used as a reinforcing material for the ion exchange membrane placed on a flat plate to scatter water.

In addition, the polyvinyl alcohol cloth used as a reinforcing material is 24
The number of threads per inch is 60 in both length and width, and the threads are made insoluble in hot water of 70° C. or higher by heat treatment.

The obtained polymer membrane was further heated at 90°C for 12 hours, then immersed in an acetalization bath consisting of sulfuric acid, mirabilite, and formaldehyde to acetalize it, simultaneously converting the sodium carboxylate into carboxylic acid, and drying at 80°C. 24 in the vessel
A cation exchange resin membrane was produced by heat treatment for a period of time.

The electrical resistance of the obtained cation exchange resin membrane was 8.5.
Ω-cm2, the diffusion constant of NaOH is 3.5X10-9c
m2/sec.

On the other hand, for the cation exchange resin membrane that was not subjected to the above heat treatment, the electrical resistance was 7.3 Ω-c2 and the NaOH diffusion constant was 2.6 x 10-8 cm2/sec.

Furthermore, as a result of salt electrolysis by the three-chamber method using each of the above cation exchange resin membranes, the former was 5.8N-Na
The latter obtained 5.2N-NaOH and had a current efficiency of 85%, while the latter obtained 5.2N-NaOH and had a current efficiency of 88%.

Example 5 20 parts of acrylic acid, 25 parts of vinyltoluene, purity 98%
0.5 parts of penzoyl peroxide is added to a mixture of 5 parts of m-divinylbenzene to obtain a homogeneous monomer mixed solution. 25% polyester, 0.02 mm thick), covered both sides with cellophane to prevent air bubbles, and then placed it between glass plates and sealed the area around it.
After heating and polymerizing at 75° C. for 48 hours under nitrogen pressure of kg/cm2, the obtained polymer film was subjected to 6. ON-NaOH
A cation exchange resin membrane was manufactured by immersing the membrane in an aqueous solution at 60° C. for 24 hours.

Then, using this cation exchange resin membrane, electrolysis of saturated saline solution was carried out by a three-chamber electrolysis method.

For comparison, a woven polyvinyl chloride and hydroxyperoxide polypropylene woven fabric with approximately the same mesh and the same thickness was used instead of the polyvinyl alcohol fabric as a reinforcing material, and a monomer mixture of the same composition was attached and polymerized to form carboxyl groups. A cation exchange resin membrane of the same type was obtained, and three-chamber electrolysis of saturated saline solution was carried out in the same manner.

Each electrolysis was carried out for 3 months.

The results are shown in Table 2.

In addition, the test using a polyvinyl chloride reinforcing material was discontinued because the NaCl concentration in NaOH reached 0.3N or higher after 52 hours.

Example 6 Fine powder 1 of polyvinyl alcohol with a molecular weight of about 25,000
0 part was dissolved in water, 5 parts of polyoxyethylene laurate (nonionic surfactant) was dissolved at the same time, and this was poured onto a flat plate to evaporate the water to obtain the remaining polymer film. .

Furthermore, after acetalizing this with glyoxal, polyoxyethylene laurate was extracted and removed with water.
A porous polyvinyl alcohol membrane with a thickness of 0.2 mm was obtained and used as a reinforcing material for the next ion exchange membrane.

On the other hand, 30 parts of styrene, 20 parts of acrylic acid, and 12 parts of divinylbenzene with a purity of about 55% were mixed as ion exchange resin components, and 1 part of diisopropylbenzene hydroperoxide was further added and mixed uniformly in a monomer mixed solution. The microporous sheet made of polyvinyl alcohol obtained above was immersed in the water, heated to 40°C in a nitrogen atmosphere, and reduced pressure to impregnate the monomer mixture into the microporous sheet. 2 at 125℃ between the plates of
The polymer film was polymerized by heating for 4 hours.

The ion exchange capacity of this is 1.9 meq/g-dry membrane,
The water content was 18% and the electrical resistance was 5.2 Ω-cm 2 .

On the other hand, the above except that a 0.2 mm thick sheet made by pressure molding a mixture of polypropylene and calcium carbonate at a ratio of 1:2 was used as a reinforcing material by immersing it in HCI and filling it with calcium carbonate eluted sheet. An impregnated ion exchange resin membrane was synthesized in the same manner as described above.

The electrical resistance of this membrane is 4.1 Ω-cm2, and the exchange capacity is 2.
1 meq/g-dry membrane, water content was 19%.

Regarding the above two types of ion exchange resin membranes, the same saturated K
Table 3 shows the results of electrolytic experiments using CI solutions.

Example 7 A polyvinyl alcohol plain-woven cloth made of 75-denier long fibers and having 60 threads per inch in both length and width was used as a reinforcing material for the ion exchange resin membrane.

Note that this polyvinyl alcohol cloth had been previously acetalized with formalin, and the degree of acetalization was 27%.

Furthermore, this is J. Polymer Sci, 3] 24
2 (1958), methacrylic acid was graft-polymerized using a tetravalent cerium salt.

On the other hand, as an ion exchange resin component, methacrylic acid 20
parts, 35 parts of styrene, 1 part of divinylbenzene with a purity of 55%
8 parts of styrene-butadiene copolymer rubber and 2 parts of penzoyl peroxide were uniformly dissolved in 2 parts of stearyl methacrylate and 30 parts of stearyl methacrylate.

In this viscous pasty mixture, the above modified width 30
A polyvinyl alcohol woven fabric with a length of Iom and a length of Iom was soaked and deaerated to uniformly adhere the ion exchange resin component to the reinforcing material, and then rolled up onto a roll with a diameter of 30 cm with cellophane sandwiched between them. The polymer was polymerized by heating at 80° C. for 48 hours in an autoclave under a nitrogen pressure of /cm 2 to obtain a polymer film.

This is 6. A cation exchange resin membrane was prepared by immersing it in ON-NaOH and converting it into sodium carboxylate.

The ion exchange capacity of the obtained cation exchange resin membrane was 2.3
meq/cm2 Moisture content 21%, electrical resistance 2.2Ω 1cm
It was 2.

As a result of electrolyzing saturated saline by the three-chamber electrolysis method using the above cation exchange resin membrane, 6. ON-NaOH was obtained, and the current efficiency was 94.0%, and the amount of NaCl in the 48% converted NaOH was 60 ppm.

It was continued for another 3 months, but after 3 months it was 5.8N-Na.
Obtain OH, current efficiency 93.4% and 48% Na
The amount of NaCl in OH was 62 ppm.

Example 8 A polyvinyl alcohol woven fabric (75 denier long fibers, 50 lengthwise and 60 widths per inch, cross-linked with glyoxal) was used as a reinforcing material, and the viscosity shown in Table 4 was used as a reinforcing material. It was immersed in a mixed monomer solution and polymerized by heating at 80° C. for 24 hours to obtain a polymer membrane.

In addition, 5% of styrene-butadiene copolymer rubber is dissolved in each of the above monomer mixtures based on the total monomers, and penzoyl peroxide is dissolved at 0.0% based on the total monomers.
01 mol% was added.

Next, the polymer membrane was immersed in 35% HCI at 60°C.
After heating for one week, 6. It was made into sodium form by soaking in ON-NaOH for 24 hours.

The obtained cation exchange resin membrane was used for three-chamber electrolysis to electrolyze saturated saline.

3. Constantly from the cathode chamber. Obtain ON-NaOH and its current efficiency and NaC in NaOH equivalent to 48% NaOH
I asked for 1.

The results are shown in Table 4.

In order to make the degree of crosslinking the same, the monomers were added in the same proportion based on the equivalent weight of all monomers.

As a result, the current efficiency of NaOH acquisition was low until the amount of methacrylic acid was up to 10% of the total ion exchange capacity.
% or more, the current efficiency increases rapidly, and at the same time
The amount of NaCl in H decreased.

This is presumed to be due to the adhesiveness between the ion exchange resin portion and the reinforcing material and the presence of carboxyl groups.

Claims (1)

[Claims] 1 A monomer mixture consisting mainly of a monomer having an ion exchange group, a monomer having a functional group suitable for introducing an ion exchange group, or a monomer having a functional group that can be easily converted into an ion exchange group is attached to the reinforcing material. When producing an ion exchange resin membrane by polymerization later, a vinyl monomer having a carboxyl group is used as one of the monomers so that the carboxyl group is present in an amount of 10% or more based on the total ion exchange capacity of the resulting ion exchange resin membrane. A method for producing an ion exchange resin membrane, which is used as a reinforcing material and is characterized in that a water-insoluble polymer compound having alcoholic hydroxyl groups present in 10% or more of all monomer units is used as the reinforcing material.