JPH0315933B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing ion exchange hollow fibers. More specifically, a method for producing an ion-exchangeable hollow fiber comprising omitting one manufacturing step to produce a porous hollow fiber into which an ion-exchange group can be introduced by a dry-wet method, and then introducing an ion-exchange group therein. Regarding.

Conventionally, porous hollow fibers are manufactured using a dry-wet method, and then an emulsion or a solvent solution of a polymer material into which ion exchange groups can be introduced is attached, and after drying, ion exchange groups are introduced therein. By introducing this method, ion-exchangeable hollow fibers were manufactured. In the present invention, the production of porous hollow fibers using a dry-wet method and the application of a polymeric substance capable of introducing ion exchange groups are performed simultaneously to produce ion-exchangeable hollow fibers that are comparable in terms of permselectivity, etc. To provide a manufacturing method by omitting one step.

The present invention also relates to a method for producing ion-exchangeable hollow fibers previously proposed by the applicant, namely forming hollow fibers with the polymer itself having aminatable groups, and then converting the hollow fibers into A method of introducing an ion exchange group by treatment with an aminating agent (Japanese Patent Laid-Open No. 1983-1999)
-174618), the strength of the obtained ion-exchangeable hollow fibers and the high price of polymers with aminatable groups such as chloromethylstyrene-styrene copolymers. However, the problem of reducing the amount used was also solved by omitting the drying process.

Therefore, the present invention relates to a method for producing an ion-exchangeable hollow fiber, and the production of the ion-exchangeable hollow fiber involves spinning a polymeric material when producing a porous hollow fiber into which ion-exchange groups can be introduced by a dry-wet method. At the same time as the stock solution is extruded from an annular hollow nozzle, an emulsion of a polymeric substance capable of introducing ion exchange groups or a solution of a solvent that coagulates the spinning stock solution is injected as an injection liquid into the core of the spinning stock solution extruded in an annular shape. , allowing it to fall naturally into a coagulation bath and coagulating it to produce a porous hollow fiber, and drying it with the injection liquid retained in the core of the produced porous hollow fiber,
This is done by introducing an ion exchange group.

Porous hollow fibers are prepared by dissolving polymeric substances such as polyvinylidene fluoride, polyvinyl fluoride, polyvinyl chloride, polyvinylidene chloride, polysulfone, polyacrylonitrile, and cellulose acetate in a solvent that is miscible with the coagulation bath. It is produced by extruding a spinning stock solution (dope solution) from the outer annular part of an annular hollow nozzle, allowing it to naturally fall into a coagulation bath that is generally water or mainly water, and coagulating there.

At this time, an emulsion of a polymeric substance into which ion exchange groups can be introduced or a solution of a solvent that coagulates the spinning dope is injected from the inner hollow part of the annular hollow nozzle into the core of the spinning dope that has been extruded in an annular shape as an injection liquid. be done. Examples of such polymeric substances include styrene-chloromethylstyrene copolymer, chloromethylated polystyrene, chloromethylated polysulfone, chlorinated polyethylene, and activated chloride such as homopolymers or copolymers of vinyl chloroacetate, chloromethyl vinyl ether, etc. Examples thereof include polymers containing groups such as styrene-butadiene copolymer, vinyl chloride-acrylonitrile copolymer, polyvinyl alcohol, and polyethyleneimine.

These emulsions of polymeric substances are prepared by any method such as dispersion of a solution of a polymeric substance in an organic solvent in water or emulsion polymerization. In addition, when the injection solution is used as a solvent solution, organic solvents that coagulate the spinning dope solution, such as carbon tetrachloride, chlorinated hydrocarbons such as perchlorethylene and trichlorethylene, benzene, toluene, and xylene, are used. Aromatic hydrocarbons such as or water are used depending on the type of polymeric substance forming the spinning dope and its solvent.

The porous hollow fibers are immersed in a coagulation bath for a predetermined period of time. Specifically, the porous hollow fibers that have passed through the coagulation bath are once wound up on a take-up roller, and then removed from the take-up roller and immersed in a coagulation solution to form a spinning stock solution. Completely remove solvent. At this time, in order to prevent the injected liquid injected into the core of the porous hollow fiber from flowing out, both ends of the fiber are clipped or crushed to seal the core, and the fiber is immersed in a sealed state. Dry in condition. Drying is carried out at a temperature below the softening point of the material forming the porous hollow fibers, whereby the organic solvent and water evaporate from the outer surface of the hollow fibers, and finally the inner surface thereof is dried.

As a result of this drying, ion exchange groups are deposited on the inner surface of the porous hollow fiber, which has a cross-sectional shape in which dense layers are present on the inner and outer surfaces, and two rows of finger structure structures are present in the intermediate layer. A material coated with a polymeric substance capable of introducing ion exchange groups is obtained, and then ion exchange groups are introduced therein.

The ion exchange group to be introduced also differs depending on the type of polymer material that can introduce the ion exchange group applied to the inner surface of the porous hollow fiber. For example, if it is a polymer material containing active chlorine, , N, N, N′,
N'-tetramethyl-1,6-hexanediamine,
aliphatic or aromatic diamines represented by tertiary diamines such as N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethyl-p-phenylenediamine; grade, grade 2 or grade 3
In the case of polyethyleneimine, anion exchange groups are introduced by quaternary ammonium chloride with various amines of the same class, and in the case of polyethyleneimine, anion exchange groups are introduced with cyanuric chloride, and in the case of styrene-butadiene copolymer, benzene nuclei are introduced with sulfone. By becoming
In the case of a vinyl chloride-acrylonitrile copolymer, a cation exchange group is introduced by hydrolyzing the nitrile group.

The ion-exchangeable hollow fiber obtained in this way has the advantage of omitting one step in its manufacturing process.
Its properties such as ion-selective permselectivity are equally effective, so by utilizing these properties,
Multiple bundled modules are subjected to diffusion dialysis, ultrafiltration,
It can be used for various purposes such as reverse osmosis.

Next, the present invention will be explained with reference to examples.

Example 1 Polyvinylidene fluoride (Kynar 460, manufactured by Pennwalt) 20 parts by weight, dimethylacetamide 78
parts by weight and 2 parts by weight of polyethylene glycol (Kanto Kagaku Products PEG #6000) were heated and mixed at 60°C,
A uniform spinning stock solution (dope solution) was prepared. Also,
Styrene and chloromethylstyrene were subjected to emulsion polymerization in equimolar amounts, and the resulting aqueous emulsion with a solid content concentration of 22% was used as a core injection liquid.

In the dry-wet spinning, a hollow annular nozzle with an outer diameter of 2.0 mm and an inner diameter of 1.5 mm is used, and the spinning stock solution is discharged from the outer annular part at a rate of 30 ml/min using a gear pump.
At the same time, the emulsion was introduced into the core of the extruded spinning dope in a circular manner at a rate of 28 ml/min by air pressure from the inner hollow part, and allowed to fall naturally over a distance of about 3 cm, and then placed in a water coagulation bath at a water temperature of 15°C. This was done by immersing it in the liquid, solidifying it, and winding it up at a winding speed of 26 m/min.

The porous hollow fiber wound around the winding roller is
It was removed from the take-up roller, and with both ends secured with clips, it was immersed in a coagulation bath for about 1 hour. Next, in this sealed state, it was placed on a glass plate, dried in an oven at 30°C for 15 hours, and then heated to N,N,N',N'-tetramethyl-1, It was immersed in a 50% aqueous solution of 6-hexanediamine for 2 hours to carry out amination, and then washed with water. The obtained hollow fiber had an outer diameter of 1.5 mm and an inner diameter of 1.0 mm.

The hollow fiber containing the anion-exchangeable quaternary ammonium base is installed in an upright glass cylinder so as to be fixed through the lids at both the upper and lower ends of the cylinder,
Desalinated water is flowed into the hollow fiber from above at a flow rate of 10/hr・m ² membrane, and a 2NH ₂ SO ₄ −1NFeSO ₄ mixed aqueous solution is flowed into the cylinder at the same flow rate from the hole inlet provided at the bottom of the cylinder. The outside of the hollow fiber was caused to flow countercurrently toward the outlet of the hole provided above the body. H ₂ SO ₄ is contained in the recovered liquid discharged from the bottom of the hollow fiber.
FeSO ₄ was contained at a concentration of 0.4 mol/ and 0.01 mol/, respectively, and selective permeation of acid was performed well.

Example 2 In Example 1, the aqueous emulsion was precipitated in water, the purified and dried styrene-chloromethylstyrene copolymer was dissolved in carbon tetrachloride, and a 3% solution thereof was used as the core injection liquid, and the coagulation was carried out. The immersion time in the bath was changed to 3 hours.

A similar selective permeation test was conducted on the obtained anion-exchangeable quaternary ammonium base-containing hollow fibers with an outer diameter of 1.5 mm and an inner diameter of 1.0 mm.
For H ₂ SO ₄ concentration 0.4 mol/, also FeSO ₄
Regarding the concentration, a value of 0.02 mol/ was obtained for each, confirming that selective permeation of the acid was performed well.

Example 3 20 parts by weight of polysulfone (UCC product P-3500), 79.5 parts by weight of dimethylformamide and polyvinylpyrrolidone (Kanto Kagaku product PVP K-90)
Using a spinning stock solution prepared from 0.5 parts by weight, 10 parts of polyethyleneimine (Kanto Kagaku Products 11308)
% aqueous solution as the core injection solution, a porous hollow fiber was produced in the same manner as in Example 1, and then immersed in a 20% ethanol solution of cyanuric chloride at 50° C. for 2 hours to carry out amination.

Similar selective permeation tests were conducted on the obtained hollow fibers containing anion exchange groups with an outer diameter of 1.5 mm and an inner diameter of 1.0 mm. As a result, the H ₂ SO ₄ concentration in the recovered liquid was 0.3 mol/, and FeSO For each of the ₄ concentrations, a value of 0.01 mol/ was obtained, confirming that selective permeation of the acid was performed well.

Example 4 In Example 1, 12 parts by weight of polyvinyl chloride (Nippon Zeon Products 103EP), dimethylformamide
A spinning dope prepared from 87.5 parts by weight and 0.5 parts by weight of polyvinylpyrrolidone was used.

A similar selective permeation test was conducted on the obtained anion-exchangeable quaternary ammonium base-containing hollow fibers with an outer diameter of 1.5 mm and an inner diameter of 1.0 mm.
0.4 mol/for H ₂ SC ₄ concentration, and FeSO ₄
Regarding the concentration, a value of 0.01 mol/ was obtained for each, confirming that selective permeation of the acid was performed well.

Claims (1)

[Scope of Claims] 1. When producing porous hollow fibers into which ion exchange groups can be introduced by a dry-wet method, a polymer material into which ion exchange groups can be introduced at the same time as a polymer substance spinning dope is extruded from an annular hollow nozzle. An emulsion of a substance or a solution of a solvent that coagulates the spinning dope,
The injection solution is injected into the core of the extruded spinning dope in a circular shape, allowed to fall naturally into a coagulation bath, and coagulated to produce a porous hollow fiber. 1. A method for producing an ion-exchangeable hollow fiber, which comprises drying the fiber while retaining an injection solution, and then introducing an ion-exchange group. 2. The method for producing an ion-exchangeable hollow fiber according to claim 1, wherein the polymeric substance into which ion-exchange groups can be introduced is an active chlorine-containing polymeric substance. 3. The method for producing an ion exchange hollow fiber according to claim 2, wherein a quaternary ammonium base as an anion exchange group is introduced.