JPS6035031A - Treatment of membraneous polymer - Google Patents

Abstract

PURPOSE:To treat uniformly a membraneous polymer without forming wrinkles and crazings, by laying the membraneous polymer on a knit of a synthetic fiber and treating it by contact with a gas or a liquid. CONSTITUTION:In treating an ion exhange membrane, a diaphragm, or other membraneous polymers by contact with a gas and/or a liquid, the membraneous polymer is laid on a knit of a synthetic fiber. The knits used may be any of weft-knitted fabrics, warp-knitted fabrics, and tubular knitted fabrics, but those knitted fabrics which are knitted on a knitting machine set at a stitch determined from the equation (wherein GG is in gauge/inch, Td is a total denier of a yarn, and 1.2<=alpha<=2.4) are the most suitable. When alpha>2.4, the stitch is too dense, it is difficult to spread the treating solution over the surface of a film, and the treatment can not be performed evenly. When alpha<1.2, the stitch is too rough, the durability is insufficient and the treatment becomes uneven.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating a membrane-like (polymer) body that is an ion exchange membrane, a diaphragm, or a membrane-attached body thereof.

Appropriate treatment is performed on the ion exchange membrane matrix to introduce ion exchange groups to obtain an ion exchange membrane, and further treatment is performed on the ion exchange membrane that already has ion exchange groups,
It is already known that it provides more favorable performance.

In this way, when processing is carried out by bringing the ion exchange membrane or the membrane-like (polymer) material that is the ion-exchange membrane matrix into contact with the processing liquid or gas, it is not possible to perform the treatment by laminating or rolling the membrane-like (polymer) materials. This is an industrially preferred method. However, as the film-like (polymer) material undergoes moisture and shrinkage during treatment, a film-like material (with at least one side of 200 cm or more and 50 cm or more)
In the case of polymeric materials, wrinkles and cracks tend to occur, and it is also difficult to process them uniformly.

For this reason, as a method for treating film-like materials on long objects,
As in No. 2193, a continuous processing method has been proposed in which a film-like material cut out from a raw roll is moved while being continuously immersed in a processing tank to obtain a processed film. However, this method has the disadvantage that the membrane itself is moved, which tends to cause scratches and wrinkles on the membrane, and that it is difficult to completely seal the treatment tank, which limits the treatment method and conditions. There was.

The present inventor has made the present invention as a result of intensive research into a method for uniformly processing both short and long lengths without wrinkles or sharpness. The present invention provides an ion exchange membrane, a diaphragm, or a membrane matrix having at least one side of 20 cm.
A method characterized in that when a film-like polymer with a length of 50 cm or more is brought into contact with a gas and/or a liquid, the film-like polymer is overlapped with a knitted material made of synthetic tam. It is. That is, in the present invention, after the film-like material is rolled or laminated together with the knitted material, it is placed in a processing tank, and a processing liquid is poured into the tank for processing. Then, the treatment liquid spreads to each part of the film-like material, causing various reactions to occur uniformly on the film surface, and the knitted material can expand and contract both vertically and horizontally, so the film-like material naturally expands and contracts during the treatment, eliminating wrinkles and cracks. It is possible to prevent this from occurring and process it uniformly. Furthermore, since the tank can be sealed, pressure reduction and reaction with gas can be carried out if necessary. Normally, ion exchange membrane treatment often involves performing two or more types of treatment one after another, but with this method, the same treatment tank is filled with different treatment solutions one after another, resulting in swelling of the membrane-like material. Since there are no wrinkles or cracks caused by shrinkage, it is possible to perform uniform multi-stage processing.

In particular, the method of the invention is characterized in that the length of one side is at least 20 cm.
In the case of a film-like material with a length of 50 cm or more, it is preferable because it is significantly better than a spacer made of Senpu Toshin.

The knitted fabric in the present invention may be any type of knitted fabric, such as horizontal knitting, vertical striped knitting, or circular knitting, but in particular, the knitted fabric may be knitted under two conditions in which the stitches at the time of knitting are based on the following chamber formula. It is highly preferable to make it a physical object.

In particular, in the present invention, it is best to knit with a coarser gauge of 1.2≦α≦2.4, rather than the conventionally said optimum gauge of 2, 6≦α≦3.3. It turned out to be extremely favorable. That is, α〉2.4
If this happens, the cells will become too clogged, making it difficult for the processing liquid to spread over the membrane surface, and the processing will not be uniform. Furthermore, the so-called draining of the treatment liquid becomes difficult, and especially when performing multi-stage treatment, it becomes difficult to replace the liquid, which is not preferable. Also α<1.
If it is 2, the mesh will be too rough and the durability will be low, and in particular, the membranes on both sides of the knitted material will come into contact with each other due to swelling of the membrane during processing.
This causes a problem of uneven processing.

The material for the yarn is selected to suit the yarn used, regardless of the type, as long as it is a synthetic fiber that is resistant to the treatment liquid, gas, and temperature used. Examples of such synthetic fibers include polyester, polyamide, aramid, acrylic fibers, polyolefins such as polyethylene and polypropylene, and halogen fibers such as saran, polytetrafluoroethylene, and copolymers of tetrafluoroethylene and other monomers. Examples include synthetic fibers.

The shape of the yarn may be multifilament yarn, monofilament yarn, or several of these yarns, but monofilament yarn alone or monofilament yarn, multifilament yarn, and/or several monofilament yarns together are particularly useful for knitting. In this case, it is preferable because it has elasticity, moderate elasticity, and split bamboo. The thickness of the yarn is particularly preferably 10 denier or more and 500 denier or less from the viewpoint of stretchability, elasticity, and handleability during knitting.

Application examples of the method of the present invention include ion exchange membranes, diaphragms, and treatments that involve dimensional changes in the matrix of these membranes.

There are various methods for laminating a knitted material made of synthetic fibers and a film-like polymer.

For example, a knitted material and a film-like polymer are stacked alternately so that the knitted material is at both ends, and then this is sandwiched between corrosion-resistant metal mesh plates larger than the knitted material and the film-like polymer. Another method is to clamp the ends of the metal mesh plate using bolts, nuts, or other clamping tools.

Another method is to alternately wrap the film-like polymer material and the knitted material around a mesh drum made of corrosion-resistant metal, and fix the ends of the cotton material to the drum with an end fixture. In addition, there is a method in which a presser made of a corrosion-resistant metal mesh shaped along the outer periphery of the drum is used to clamp and fix the drum between the presser and the drum.

In either method, the membrane-like polymer is not directly fixed (in contact) with a fixture such as a metal mesh plate or drum, but is sandwiched between knitted materials that are fixed to the fixture in some way. It is important to maintain the condition.

In other words, taking the above-mentioned fixing method using a metal mesh plate as an example, if a laminate is fixed with a bolt passing through the membrane polymer at the end of the membrane polymer, shrinkage of the membrane polymer during processing will occur. During expansion, a large stress is applied to the film-like polymer, making it meaningless to overlap the knitted material and the film-like polymer. On the other hand, without passing the bolt through the membranous polymer,
By applying pressure between the metal mesh plates, the membranous polymer is held under pressure between the knitted materials, so even if the membranous polymer contracts or expands during processing, the membranous polymer will remain intact. The appearance of wrinkles and cracks is prevented.

Regarding the production and processing of cation exchange membranes, sulfonation,
Examples include saponification, exchange of adsorbed ions, adsorption treatment of other substances, and other treatments. Regarding the production and treatment of anion exchange membranes, amination treatment, haloalkylation treatment, 4
Examples include grading treatment, exchange of adsorbed ions, adsorption treatment of other substances, and other treatments. For composite ion exchange membranes, treatment similar to the above can be performed. Furthermore, extraction, liquid equilibration, and other treatments are possible for other diaphragms. That is, the method of the present invention is an extremely useful method for uniformly carrying out treatment without wrinkles or sharpness in gas or liquid contact treatment that involves dimensional changes in film-like materials. It is particularly useful in the industrial treatment of membrane-like materials with at least one side of 20 cm or more, and even 50 cm or more.

That is, width 0.211~3I11, length 1000~5
Even a long film-like material such as 000+s I) can be rolled together with a knitted material, placed in a processing tank, and processed uniformly without defects such as cracks, which is extremely useful industrially.

Next, the method of the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

In addition, the leakage water permeability in the following examples and comparative examples is as follows:
Measurement area 2dm2. It was calculated from the value measured at a predetermined differential pressure under conditions of a measurement time of 1 hour.

In addition, "1 part" in the following Examples and Comparative Examples is "part by weight"
means.

Example 1 Polypropylene 250 denier (monofilament) yarn and polyester 50 denier (24 filament)
The threads, each thread, were run together horizontally at mj& to make a knitted fabric at 7 gauge/inch (α in this case = 1.28
). The finished knitted fabric had approximately 5 wells/inch and approximately 5 courses/inch.

On the other hand, a thick film (membrane matrix) of an anion exchange membrane was prepared as follows. That is, 50d was subjected to electron beam irradiation in an N2 atmosphere.
polypropylene woven fabric with divinylbenzene (purity 55
%), 25 parts of 4-vinylpyridine, 55 parts of styrene, 30 parts of dioctyl phthalate, and 0.5 parts of benzoyl peroxide.The membrane was then heated and polymerized to form a thick anion exchange membrane.

Fifty sheets of this thick film 50cm x 50cm were stacked alternately with the above knitted fabrics of the same size (after both ends were knitted), 8
Sandwich it between 0cm x ElOcm square stainless steel mesh plates, fasten the four corners of this mesh plate with bolts and nuts,
The membrane spacer was made to stay in place even when standing upright. this,
Internal dimensions are width 7cm, width 82ci + height and depth) 85cm.
After evacuating the inside of the reaction tank, methyl chloride gas was fed into the reaction tank and heated to 1.2 atm at 80°C for 4 hours.
The mixture was held for 0 hours and subjected to quaternization treatment. Next, the inside of the reaction tank was filled with N.
After replacing with 2 gases, acetone was supplied at room temperature to extract dioctyl phthalate in the membrane. Next, after the acetone was extracted, 0.5N saline was supplied at room temperature to wash the membrane, and the saline was refreshed several times to achieve good equilibrium, after which the anion exchange membrane was taken out. The removed membrane had no wrinkles or cracks, and its resistance in 0.5N saline was 1.1 (Ω-cm2±
Uniform at 0.1Ω9cm2, and differential pressure 0.2kg/am2
No leakage water permeability was observed under hydrostatic pressure.

O Comparative Example 1 A thick film of the same anion exchange membrane as in Example 1 was superimposed with a 0.5 mm thick diagonal mesh made of lipropylene (Netron #il manufactured by Tokyo Polymer Co., Ltd.) instead of the knitted fabric of Example 1. Thereafter, the same treatment as in Example 1 was performed to obtain an anion exchange membrane. The obtained anion exchange membrane had severe wrinkles and was ranked 45 out of 50.
Sharpness had occurred in one of the membranes. The resistance of the membrane in 0.5N saline solution is 1.7Ωcm2±0.2Ω・C2, and the amount of leakage water permeation under hydrostatic pressure with a differential pressure of 0.2kg/cm2 is 100 to 380m1 if the membrane is not cracked by the naked eye. /hr=m2(5
), and the other 45 membranes were over 500 m1/hr-m2 and could not be used as anion exchange membranes.

Example 2 A 275-denier (monofilament l-) yarn of ethylene/tetrafluoroethylene alternating copolymer was run on a weft machine to make a knitted fabric at 8 gauge/inch (α in this case = 1.40).
). The finished knitted fabric had approximately 4 wells/inch and approximately 4 courses/inch.

On the other hand, cation exchange membrane original 1! (Membrane matrix) was prepared as follows. N, 50d subjected to electron beam irradiation in an atmosphere
polypropylene woven fabric with divinylbenzene (purity 55%)
) 20 parts, styrene 80 parts, dibutyl phthalate L/-t 40 parts
After impregnating it with 0.5 parts of benzoyl peroxide monomer solution, heating polymerization was performed to obtain the raw material 11 of the cation exchange membrane.
I was shocked.

Fifty sheets of this thick film 50 cm x 50 cI 11 square were stacked alternately with the knitted fabric of the same size (after both ends were knitted),
It was sandwiched between 80 cm x 80 cm square stainless steel mesh plates, and the four corners of the mesh plates were fastened with bolts and nuts to prevent the membrane spacer from shifting even when it was stood up. The inner dimension of this is I
f] 7cm, width f (2cm, height and depth) 85c+
The mixture was placed in a reaction tank with a lid on. Next, anhydrous sulfuric acid-dioxane adduct saturated dichloroethane solution was circulated for 5.040 hours to effect sulfonation. After draining this sulfonated solution, an alkali-methanol solution was supplied at room temperature, followed by a 0.5N saline solution in which the sulfonic acid groups on the membrane were replaced with Na-type, to wash the membrane, and the saline solution was renewed several times. well balanced,
Thereafter, the cation exchange membrane was taken out. This membrane has no wrinkles or sharpness, and the resistance in salt water is 2.1Ω・cm2 ± 0.2Ω, C11.
2, and no leakage water permeation was observed under hydrostatic pressure with a differential pressure of 0.2 kg/cm2.

Comparative Example 2 A thick cation exchange membrane similar to that of Example 2 was used instead of the knitted fabric of Example 2, and ethylene/tetrafluoroethylene alternating copolymer 2 was used.
After overlapping with a Mikoshiro woven fabric made of 75 denier (monofilament) yarn, the same treatment as in Example 2 was carried out to obtain a cationic membrane. All of the obtained cation exchange membranes had wrinkles and cracks, and the membrane resistance in 0.5 cm saline solution was 2.3Ω・0m2~1OΩ in one membrane.
・There was a wide variation in size of cm2 or more. Also, differential pressure 0.2k
Leak permeability under hydrostatic pressure of g/cfl12 is 500m
Many of the membranes exceeded 1/hr-m2 and could not be used as cation exchange membranes.

Example 3 A knitted fabric was made from polypropylene 150 tenier (monofilament) yarn using an 18 gauge circular knitting machine (α=2.32 at this time). The finished knitted fabric had a size of about 9 wells/inch and about 12 courses/inch, which was cut open, heat set, and the ears were fixed to make a knitted fabric about 80 cm wide and 2n+ long.

Diameter of stainless steel mesh with upper and lower brim: 1 Oct 1
1 Place two anion exchange membranes prepared in the same manner as in Example 1 onto a drum with a height of 70 cm, one at a time, so that the membranes do not overlap.
This knitted fabric was wrapped around the knitted fabric while being inserted into the zero-ply knitted fabric, and the ends of the knitted fabric were fixed to the upper and lower brim with stainless steel wire. This drum was placed in a reaction tank with an inner diameter of 30 cm+ and a height of 75 cm, and after the lid was closed, 0.5N saline solution containing 5Z sodium polystyrene sulfonate dissolved therein was circulated at 82°C for 48 hours to perform monovalent ion selective permeation treatment (Tokuko Showa). 45-191180). The obtained anion exchange membrane had no wrinkles or cracks, and no leakage water permeation was observed under a hydrostatic pressure with a differential pressure of 0.2 kg/am2. The membrane resistance in 0.5N saline solution after treatment was 1.7Ω・cI12±0.1Ω・cm′, and when combined with a normal cation exchange membrane (Aciplex ■-102 manufactured by Asahi Kasei Corporation) 4A/dm2.2
The specific permselectivity (Fso4) of sulfate radicals with respect to chloride ions when electrodialyzed seawater at 5°C was as good as 0.02.

4 Where, N: Specified concentration of each ion in the concentrate C: In seawater
// Comparative Example 3 M ions of an anion exchange membrane were prepared in the same manner as in Example 2, except that a Mikoshiro woven fabric made of polypropylene 1507'neal (monofilament) yarn was used instead of the knitted fabric in Example 3. Selective permeation treatment was performed. The obtained anion exchange membranes had more wrinkles as they got closer to the inner side, and 13 membranes from the inner side were visually observed to have generation of dust. The leakage water permeability under hydrostatic pressure with a differential pressure of 0.2 kg/cm2 is 100 ml/hr for the membrane on the outside of the roll.
m2 increases inward and the film with cracks is 500 m1/
At hr-+m2 or more, it could not be used as an anion exchange membrane. Membrane resistance in 0.5N saline solution is 1.7Ω・
Cm2±0.2Ω, C112, F504=0.0
There was a wide variation between 2 and 0.06.

5 Example 4 A polypropylene 50 denier (monofilament) yarn and a polypropylene 30 denier (9 filament) yarn were each used, and a warping machine was used for knitting. 20
A knitted fabric was made using a double chinpi knitting structure using a Russell knitting machine with a two-piece spacing of one gauge/inch and a knitting condition of 15 courses/inch on the machine (α = 1.88).
. The resulting fabric was a knitted fabric of 8 rugs/inch and 7 coats/inch. A long cation exchange thick film was prepared using the following method. 30 denier polypropylene woven fabric subjected to electron beam irradiation in N2 atmosphere
After being rolled up together with the polyester film into the inner drum of a polymerization machine of the same type as described in Example 4478 (a device having a fixed inner drum, a fixed outer drum, and an injection port for injecting the processing liquid into the space formed by both the inner and outer drums). , set in an outer drum, and feed a polymerization solution consisting of 20 parts of divinylbenzene (purity 55%), 80 parts of styrene, 40 parts of dibutyl phthalate, and 0.5 parts of benzoyl peroxide,
Thereafter, the temperature was gradually raised from 30°C to 6°C to complete the polymerization. After the polymerization was completed, the polyester film was peeled off from the inner drum and the heavy metal membrane sheet was taken out. This cation exchange thick film has a thickness of 0.12
mm, width 1.4+a, and length 2000 m.

This long cation exchange membrane 2000+a was put together with the above-mentioned knitted fabric into a stainless steel mesh with a diameter of 30 mm with flanges on the top and bottom.
It was rolled into a drum with a height of 1.8 m. This was placed in a reaction tank, and after the lid was closed, dibutyl phthalate was first extracted with dichloroethane, and then sulfonation, Na type substitution, and 0.5N saline equilibration were performed in the same manner as in Example 2. The removed cation exchange membrane becomes rolled up and becomes more inward.
Although there were some wrinkles, no stains were observed. Five points were sampled every 500 m, and membrane resistance and leakage water permeability were measured. The resistance in 0.5N saline is 1.8
Uniform Ω・am2±0.3Ω・0m2, and differential pressure 0.2
No leak water permeation was observed under a hydrostatic pressure of kg/cm2.

Example 5 Polypropylene 100 denier (monofilament) yarn and polyamide fiber (Asahi Kasei Corporation 7 Leona) 70 denier (24 filament) yarn each
Each piece of wood was put on a horizontal stitching machine to make a knitted fabric with a 12 gauge (α=1.[i5). The finished knitted fabric had approximately 6 wells/inch and approximately 10 courses/inch.

A long anion exchange thick film was prepared in the following manner. A 30-denier polypropylene woven fabric that had been irradiated with an electron beam in an N2 atmosphere was wrapped together with a polyester film around the same inner drum of the polymerization machine as in Example 4, and then placed in the outer drum, and divinylbenzene (purity 55%) 19
parts, 23.5 parts of 4-vinylpyridine, 57.5 parts of styrene
1 part, 25 parts of dioctyl phthalate, and 0.5 parts of benzoyl peroxide, and then 3 parts of
The temperature was gradually raised from 0°C to complete polymerization. After the polymerization was completed, the heavy metal membrane sheet was taken out from the inner drum to obtain a long anion exchange thick membrane (thickness 0, 12 mm, width 1.
4mm, length 2000m).

This long thick anion exchange membrane was wound together with the above-mentioned knitted fabric into a reaction drum similar to that described in Example 4, and placed in a reaction tank. Thereafter, quaternization with methyl chloride gas, extraction of phthalate ester, and equilibration with 0.5N saline solution were carried out in the same manner as in Example 1 to obtain a long anion exchange membrane. The obtained anion exchange membrane had some wrinkles toward the inner side of the membrane, but was in good condition with no cracks. Five points were sampled every 500I11, and membrane resistance and leakage water permeability were measured. The resistance in 0.5N saline was 1.5Ω, C112±0.2Ω0cm2, and no leakage water permeation was observed under hydrostatic pressure with a differential pressure of 0.2kg/cm2.

Applicant: Asahi Kasei Industries, Ltd. Agent Yutaka 1) Yoshio 9

Claims (2)

[Claims] (1) When ion exchange membranes, diaphragms, or membrane-like polymers attached to these membranes are brought into contact with gas and/or liquid and treated, a cotton-like substance made of synthetic m fibers and a membrane-like polymer are A method for treating a film-like polymer, which is characterized by carrying out the treatment in layers. (2) A gauge in which the m-shaped object is expressed by the following formula: GG = αφ square 1] (where GG: gauge/inch, Td: total denier of thread), where α is 1.2≦α≦2.4 2. The method for treating a film-like polymer according to claim 1, which is a knitted product knitted using a knitting machine.