JPS58132112A - Production of hollow fiber - Google Patents

Abstract

PURPOSE:When a spinning dope of polysulfone resin is extruded out of annular nozzles into hollow fibers, a specific injection solution is used to produce hollow fibers which is suitable for use as a separation membrane, because of their few yarn breakages and small deviation in wall thickness. CONSTITUTION:A spinning dope of polysulfone resin is extruded from the outer annular part of the nozzles for hollow fibers, meanwhile a liquid causing no caugulation of the dope such as ligroin is sent from the inner part of the nozzles into the hollow part of the fiber simultaneously and the resultant fibers are made to fall down by their own weight, led into the gelation bath of water or mainly containing the same to form fibers, which is then wound up.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing hollow fibers. For more details,
This invention relates to a method for producing polysulfone resin hollow fibers that are effectively used as separation membrane materials.

Polysulfone resins contain sulfone bonds that are resistant to oxidation, ether bonds that provide toughness and thermal stability, and benzene rings that improve heat resistance, etc. in their molecular skeleton structures, so they are well-balanced and have excellent properties. have a characteristic. In other words, its mechanical strength is equivalent to that of poly7-ethylene oxide resin, and its thermophilic temperature (174°C) is second only to polypropylene resin, and it has especially excellent creep resistance at high temperatures and excellent chemical resistance. It has properties such as not being attacked by acids and alkalis, and is also easy to spin into hollow fibers, making it suitable for use as a separation membrane material under harsh conditions such as organic solvent separation, organic matter recovery, and wastewater treatment. (high temperature, strong acidity or strong alkalinity, etc.)
However, both can be used effectively.

To manufacture hollow fibers from polysulfone resin used in such applications, a spinning stock solution (dope solution), which is a highly concentrated solution of polysulfone resin, is extruded from a hollow annular nozzle, and
After allowing it to fall naturally through several tens of cfIK, it is introduced into water or a gelatinizer whose main component is water, and is gelled there. At this time, a liquid is injected into the hollow part and the hollow part is We are trying to maintain this. For this purpose, a liquid that coagulates the spinning dope, such as water, alcohol, acetone, or a mixture thereof, has conventionally been used.

By the way, when a coagulating liquid is injected into the hollow fiber to maintain the hollow part, when the spinning stock solution discharged from the outer annular part of the nozzle comes into contact with this liquid injected from the inner hollow part of the nozzle, Gelation immediately starts from the inside of the hollow fiber, and the gelled layer on the inside gradually develops, but when the spun hollow fiber is drafted and stretched,
When coagulating liquid is injected into the hollow part, rapid gelation from the nozzle part causes thread breakage to occur frequently. In addition to fiber breakage, the inner wall of the hollow fiber cross section may not be circular because the hollow fiber shrinks in the circumferential direction, and if the flow at the nozzle is uneven, gelation occurs too quickly and uneven thickness may occur. Hollow fibers can be formed as they are, and hollow fibers that are spun while passing a coagulating liquid inside form a double skin layer on the inner and outer surfaces, so they can be used as separation membrane materials. At the same time, there are also disadvantages such as a decrease in the efficiency of mouth passage.

As a result of various studies on the causes of these drawbacks, the present inventor found that gelation of the hollow flow of the spinning stock solution flowing out from the nozzle part occurred rapidly, that is, this gelation was caused by the IJ sulfone resin that constitutes the spinning stock solution. This is thought to occur as a result of agglomeration of the resin component when the solvent in the two components is replaced with, for example, water injected into the hollow part, and the resin component is used as the liquid injected into the hollow part. It has been found that all of the above-mentioned drawbacks can be overcome by using a material that does not dissolve or are compatible with water, that is, does not coagulate the spinning dope.

Therefore, the present invention relates to a method for producing hollow fibers, and the production of hollow fibers involves extruding a polysulfone resin spinning stock solution through a hollow annular nozzle, introducing it into water or a gelling bath mainly composed of water, and spinning hollow fibers. At this time, a liquid that does not coagulate the spinning dope is used as the injection liquid to maintain the hollow portion.

Liquid hydrocarbons such as kerosene, ligroin, hexane, benzene, and toluene are generally used as liquids that do not coagulate the spinning dope.

As the polysulfone resin to be spun into hollow fibers, polysulfone obtained by reacting sodium salt of bisphenol A and p+p'-dichlorodiphenyl sulfone in dimethyl sulfoxide is generally used. Similarly, ethers obtained by dehydrochlorination and 2-condensation polymerization or sulfonated polysulfones can also be used.

Solvents used to dissolve the polysulfone resin and form the spinning dope include dimethylformamide, diethylformamide, dimethylacetamide, diethylacetamide, morpholine, N-methyl-2-pyrrolidone, tetrahydro7rane, dimethylsulfoxide, and the like. Among these, dimethylformamide, diethylacetamide, N-methyl-2-biHI7, morpho-IJ and the like are preferably used. The polysulfone resin spinning dope dissolved in these solvents generally has a molecular weight of about 70 to 8
5f! Amount-1 It is prepared and used at a concentration of about 70 to 85 f.

Using such a spinning dope and the injection liquid, spinning and drafting of a single hollow fiber are performed in the same manner as in conventional methods. Therefore, if water or a substance containing water as the main component is used as a coagulation bath and other components are added, a small amount of surfactant or the same type as that used for preparing the spinning dope may be used. A solvent such as a force τ is used.

In this way, when spinning hollow fibers, as a result of using a liquid that does not coagulate the spinning stock solution as the injection liquid to maintain the hollow part, (1) it is possible to perform spinning with fewer fiber breakages (2) ) Hollow fibers with less uneven thickness can be manufactured (3)
) It is possible to manufacture hollow fibers with a skin layer formed only on the outer surface. (4) The winding speed can be increased compared to cases where conventional spinning and drafting methods are adopted. This improves efficiency, which leads to the production of large quantities of hollow fibers and the ability to produce thinner hollow fibers.If thinner hollow fibers are obtained, when used as a membrane material for separation, the container containing the membrane material can be The hollow fibers obtained in this way are useful for separation purposes such as ultrafiltration membrane materials or reverse osmosis membrane materials. It can be effectively used as a membrane material.

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

Example 1 A spinning stock solution prepared from 25% polysulfone, 74% dimethylformamide, and 1% polyvinylpyrrolidone (thickener), all by weight, was heated to an inner diameter of 1 day and an outer diameter of 2 W.
A 1M hollow annular nozzle was used to discharge from the outer annular part at a discharge rate of 33 mm, and at the same time, ligroin was simultaneously fed from the inner hollow part as the injection liquid at a rate of 3.8 sd/min, and between 10a** After allowing it to fall naturally, it was introduced into a gelatinizer having a composition of 99 parts of water and 1 weight or less of dimethylformamide, and wound up at a winding speed of 60 m7 to form an inner diameter of 0.3 cm and an outer diameter of 0.7 cm. - hollow fibers were obtained.

The cross-sectional view (100x magnification) of the obtained hollow fiber is shown in photograph 1 (substitute for drawing), and the outer surface (10,000x magnification) and inner surface (500x magnification) are shown in electronic 'ama' photographs in superimposed photographs 2 and 3, respectively. As shown in the figure, there was no uneven thickness, and the skin layer was formed only on the outside, so there was no yarn breakage during drafting, and smooth spinning was possible. When this hollow fiber is used as an ultrafiltration membrane material for ultrafiltration, more than 95% of the dissolved polyethylene glycol can be removed when applied to a double-strike aqueous solution of polyethylene glycol with a molecular weight of 20.000. Ta.

Example 2 Polysulfone, both 28.5% by weight, 66.5%
of dimethylacetamide and 5% polyvinylpyrrolidone;
2 +: Discharge 1B from the outer annular part at 6.3-7 minutes discharge I from the q hollow nozzle, and at this time, simultaneously feed kerosene as the injection liquid from the inner hollow part with a 1.8 m 7 minute injection needle, 46 ．． After allowing it to fall naturally between M and M, it was introduced into a gelling bath consisting of 100% water, and was wound at a rate of 54 m/min.
Three hollow fibers were obtained. In this case as well, there was no yarn breakage during drafting, and spinning could be carried out smoothly.

[Brief explanation of the drawings] The photographs substituted for drawings are all related to the hollow fiber described in Example 1.
are electronic #B mirror photographs showing the outer and inner surfaces, respectively. 83 Procedures Written by Masaru Nezu (self-motivated) Display of the case dated January 16, 1988 Patent Whale No. 1518 No. 2 of 1988 Name of the invention Method for manufacturing hollow fiber & Relationship with the case of the person making the amendment Patent applicant Name (438) Japan Oil Seal Industry Co., Ltd. Principal Agent Address No. 501 Ato Building, 2-7 Shiba Daimon Yu, Minato-ku, Tokyo Procedure amendment method in the detailed description of the invention in the specification subject to amendment B) % formula % Display of the above case Showa δ〒Tokyo Patent Application No. 15184 λ Name of the invention Hollow fiber manufacturing method 3 Person making the amendment Relationship to the case Name of patent applicant (43B) Japan Oil Seal Industries Co., Ltd. Representative agent address Tokyo Contents of correction of the date of the order by Ato Building No. 501 δ Nemasa, Shiba Daimon, Minato-ku (1) "Photograph substituted for drawing l" of "Drawing substitute photo l", "
Display of ``Drawing Substitute Photo 2'' and 1 Drawing Substitute Photo 3'',
Corrected to [Figure 1], [Figure 2], and [Figure 3], respectively. (2) The statement on page 8, lines 9 to 12 is corrected as follows: ``The obtained hollow fiber has a cross-sectional fiber structure (100x magnification) in Figure 1, and a tfC Figure 2. and Fig. 3 shows its outer side (10,000x magnification) and inner side (5x magnification), respectively.
000 times) is shown as an electron micrograph. J (3) The column for the brief explanation of the drawings should be corrected as follows. [Figure 1 shows the fiber structure of the cross section of the hollow fiber obtained in Example 1, and Figures 2 and 3 show the outer and inner sides of the hollow fiber, respectively. It is an electron micrograph showing the fiber shape of 1III11. ”

Claims (1)

[Claims] 1. A polysulfone resin spinning stock solution is extruded through a hollow annular nozzle and introduced into water or a gelatinized liquid containing water as the main component,
1. A method for producing hollow fibers, which comprises using a liquid that does not coagulate the spinning dope as an injection liquid for maintaining the hollow portion when spinning the hollow fibers. 2. The hollow fiber manufacturing method according to claim 1, wherein a liquid hydrocarbon is used as the injection liquid. 3. The method for producing a hollow fiber according to claim 1, wherein the spun hollow fiber is used as a separation membrane material. 4. The method for producing a hollow fiber according to claim 3, wherein the separation membrane material is an ultrafiltration membrane material or a reverse osmosis membrane material.