JPS60248202A - Hollow fiber membrane and its preparation - Google Patents

Abstract

PURPOSE:To prepare a hollow fiber membrane having high heat resistance and chemical resistance causing clogging scarcely in spite of small internal pore size by prepg. a hollow fiber membrane comprising polyphenylene sulfide resin having a dense layer provided with fine internal pores and a spongy layer adjacent to the dense layer. CONSTITUTION:The soln. of polyphenylene sulfide resin having constitution units expressed by the formula is extruded through an annular nozzle. At the same time, coagulable liquid comprising a good solvent for polyphenylene sulfide and nonsolvent for the polyphenylene sulfide is introduced into a core part of the annular nozzle. Useful coagulable liquid is such as a mixture of N-methyl-2- pyrrolidone as a good solvent with diethylene glycol and water as nonsolvent. By this method, a hollow fiber membrane having a dense layer provided with fine internal pores having <=0.025mu pore size, and a spongy layer contg. >=20vol% cavity having >=1mu pore size adjacent to the dense layer is obtd.

Description

[Detailed Description of the Invention] General Summary The present invention relates to a hollow fiber membrane made of polyphenylene sulfide resin, more specifically, a polyphenylene sulfide hollow fiber having a dense surface layer on the inner surface and a spongy texture layer in contact with the membrane. Concerning membranes and methods of manufacturing them.

The object of the present invention is to industrially advantageously obtain a hollow fiber membrane with small inner pores and less clogging.

Polyphenylene sulfide was originally developed as an engineering plastic, so it has excellent heat resistance, is not attacked by acids or alkalis, has excellent chemical resistance, and has excellent mechanical properties and fire resistance. It is excellent. Focusing on such points, the present inventors conducted extensive research on polyphenylene sulfide hollow UJ4 fibrous membranes and methods for producing the same, and as a result, arrived at the present invention.

<Industrial Application Field> The hollow fiber membrane of the present invention can be used for diaphragm separation in ultrafiltration and microfiltration by incorporating a large number of them into a module.

In particular, it has excellent heat resistance and chemical resistance, so it
Factory for electrocoating of home appliances, chemical products, pulp, dyes, recovery of valuables from wastewater and reuse of water, plating, pickling, recovery of metals and inorganic salts from surface treatment wastewater and reuse of water, etc. Wastewater treatment, separation and purification of proteins, enzymes, sugars, etc. in the pharmaceutical and fermentation industries, ultrapure water production in the electronics industry, streamlining of manufacturing processes such as concentration, brine removal, and clarifying filtration in the food industry, as well as paint and It can demonstrate its properties in solvent recovery at painting and paint factories, and organic solvent processing in the food, petrochemical, and chemical industries.

Further, the polymer used in the present invention has polyphenylene sulfide (hereinafter abbreviated as PPS) as a main component, and PPS has an unpaired electron in the sulfur in the main chain.

Using this, it can be chemically modified or used as a complex. For example, enzymes can be immobilized on microporous hollow fibers to form highly functional membranes such as those used in bioreactors as enzyme-immobilized membranes. Also, AsFy
, SbF5, ■, 11λ504, electron acceptors such as SO3, Li, , storium naphthalene, N(C4
114) - When the hollow fiber membrane of the present invention is doped with an electron donor such as ClO4, electrical conductivity is improved due to the effect of dramatically increasing the membrane area due to the microporous structure and the presence of benzene rings and sulfur in the main chain. Degree is 10-8mho/c+o
(25℃) or higher, precious metals and
Recovery of heavy metals, electrodialysis membranes, selectively permeable membranes that separate specific substances from aqueous electrolyte solutions or solutions consisting of electrolytes and non-electrolytes, separation of specific gases from polar and non-polar mixed gas systems, and electrical resistance and Applications that utilize changes in power;
For example, it can be used for humidity sensors, gas sensors, etc.

Further, the hollow fiber membrane of the present invention is used as a support for a minute R membrane, and the hollow fiber membrane of the present invention is immersed in a solution of a polymer such as polysulfone, taken out, dried, and the solvent removed to remove the zero content of these polymers. If a composite membrane is prepared in which a dense skin layer with a thickness of .1 to 1.5 μm is formed on the surface of the hollow fiber of the present invention, it can be used as a reverse osmosis membrane or a gas component MI IW. Polymer solutions that can be used for these purposes include polydimethylsilicon, polydiphenylsilicon, polyladder organosiloxane, polydimethylsilicon carbonate, polycarbonate, cell-side course acetate-1, polyvinyl alcohol, polysulfone, and polyether. It can be selected from solutions of at least one polymer selected from sulfone, polyimide, polymethacrylate, polyarylene oxide, and protein oxide.

Fabrics woven by cutting the hollow fiber membrane of the present invention into short fibers can be used as sweat-absorbing clothing, medical bandages, firefighting suits, and work clothes at hot work sites due to their sweat-absorbing, heat-insulating, and heat-resistant properties. You can make the most of it. In addition, it has a large ability to absorb and retain oil, so it can be used as an oil fence.

As described in detail below, the hollow fiber membrane of the present invention has excellent heat resistance and chemical resistance, and takes advantage of the features of having an unpaired electron in the sulfur atom, and can be used in addition to conventional fields of application. A wider range of applications is possible. Of course, the hollow fiber membrane of the present invention is not limited to the examples in item 1-.

<Structure of the Invention> The first invention of the present invention is a hollow TA fiber membrane made of polyphenylene sulfide resin, which has pores with a diameter of 0 on its inner surface.
．． It has a dense layer with micropores of 0.025μ or less, and in contact with this dense layer, there are cavities with a diameter of 1μ or more at a volume ratio of about 2.
It is a hollow fiber membrane having a spongy silk layer containing 0% or less.

The polyphenylene sulfide resin that constitutes the membrane is -a
refers to polymers that The copolymerization component is 10 mol%
When a trifunctional or higher functional phenyl, biphenyl, naphthyl sulfide bond, etc. is selected for copolymerization as a hydrogen group, an alkoxy group, a carboxylic acid group, or a carboxylic acid rich group, the amount is preferably 3 mol% or less, more preferably 1 mol% or less. .

Furthermore, the polyphenylene sulfide resin of the present invention may be a composition partially containing other components; for example, it is also possible to blend other resins within a range that does not adversely affect moldability. Other polymers that can be blended include polyethylene terephthalate, polybutylene terephthalate, nylon-6, nylon-66, polycarbonate,
Polyoxymethylene, polyphenylene oxide, poly-
Examples include crystalline polymers such as 4-methylpentene-1, polypropylene, polynatrough 110 ethylene, and polyetheretherketone, and amorphous polymers such as polysulfone and polyethersulfone. Further, such raw material resin may contain appropriate amounts of additives such as antioxidants, antistatic agents, antibacterial agents, lubricants, flame retardants, and surfactants, as required.

The second invention of the present invention is a method for manufacturing such a hollow fiber membrane, in which a solution containing PPS as described above is extruded from an annular nozzle, and PPS is added to the core of the annular nozzle.
A coagulable liquid consisting of a mixture of a good solvent and a non-solvent is introduced and then coagulated.

As a solvent for forming the PPS solution, a good solvent as described below is used, but a mixed solvent containing a portion of a non-solvent may also be used.

The coagulating liquid introduced from the core of the annular nozzle coagulates the hollow fiber membrane from its inner surface, so it is called internal coagulating liquid for convenience, and is a hollow body formed to coagulate the hollow wire 1# membrane from its outer surface. For convenience, the coagulation bath into which the
i M#Nu is solidified. Of course, the coagulated membrane then undergoes a water washing process and the like.

As a result of intensive research into good pps solvents that do not dissolve in organic solvents at room temperature, the present inventors found that N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N- Dimethylacetamide, N-ethyl-2-pyrrolidone, N-methyl-ε-caprolactam,
It was discovered that organic amide solvents such as hexamethylphosphoramide and aromatic solvents such as α-chlornaphthalene are good solvents. Especially N-methyl-
2-pyrrolidone is preferred. These can be used alone or in combination of two or more. The boiling point of these solvents is around 200° C. under normal pressure, and naturally they act as good solvents under pressure.

In addition, suitable non-solvents include water, methanol, ethanol, etc., and polyhydric alcohols having 2 to 4 carbon atoms. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, glycerin, butanediol, allyl alcohol, etc. There is. These and water can be used alone or in combination of two or more.

As the non-solvent to be contained in the PPS melt serving as the spinning dope, the above-mentioned polyhydric alcohols may be used alone or in combination with water.

The spinning dope may be a mixture of 52 to 40% by weight of PP and 0 to 35% by weight of a non-solvent with a good solvent.

As the external coagulating liquid used in the coagulating bath, non-solvents for PPS such as water, methanol, ethanol, ethylene glycol, propylene glycol, glycerin, and butanediol can be used alone or in combination.

The internal coagulating liquid introduced into the hollow part of the fiber membrane is pp
A mixed solvent of a good solvent and a non-solvent is used. Among these, the non-solvents in particular are those with a viscosity of 0.7 to 2 CI) S (centivoids) (referred to as non-solvent A), and those with a viscosity of 3 to 50 c,p
It is desirable to use s (referred to as non-solvent B) in combination. Furthermore,
It is preferable to mix three types of such internal coagulation liquid, a non-solvent and non-solvents A and B, so that the coagulation value is 12 to 18 and the viscosity is 3 to 40 cps. What is the coagulation value mentioned here?
A solution of PPS dissolved in N-methyl-2-pyrrolidone to a concentration of 1 needle % at 50 mA! It is a numerical value expressed in mρ, which is the amount of coagulating liquid required to obtain cloudiness - 1. (The viscosity is the value at 30°C, and the coagulation value is the value at 240°C.) By the way, regarding the coagulation value, non-solvent A
that of non-solvent B is 4-10, and that of non-solvent B is 15-20.
It is.

The reason why a mixed solvent of three types is used in this way is that it is particularly preferable to form a sponge layer and a skin layer at the same time without making the film structure uniform, and to improve the permeability of gases, liquids, etc. be. Furthermore, if the proportion of the good solvent is lowered, there are problems such as the spinning not being perfectly circular and the spinning speed decreasing.

The non-solvent A is involved in the formation of an internal skin, and the lower the coagulation value and viscosity, the better. If the non-solvent A has a coagulation value of 10 or more and a viscosity of 2 cps or more, it is difficult to form an internal skin. Examples of such non-solvents include water, methanol, and ethylene glycol. Non-solvent B adjusts the coagulation value and viscosity of the internal coagulation liquid and is involved in the formation of voids. Non-solvents that correspond to this include saturated polyhydric alcohols having 2 to 4 carbon atoms, ethylene glycol, and propylene. Examples include glycol, glycerin, butanediol, and the like.

The spinning of the present invention employs a dry-wet method, and normally in this method, a draft is created in the yarn section immediately after it is extruded from the nozzle, allowing high-speed spinning. However, if a highly coagulating liquid is used as the internal coagulating liquid, Gelation of the extruded spinning solution
Coagulation occurs instantaneously, resulting in thread breakage and the like, resulting in insufficient spinning speed.

Internal coagulation liquid viscosity 1 cps or more, preferably 3 cps
The above method has the effect of delaying the gelation and coagulation portion as described above9-, so the draft is more likely to appear, and therefore the spinning speed is improved.

By doing this, evening ■ (¥ 3011 m ~ 5
A hollow fiber membrane of H is obtained. This membrane has a spongy tissue layer on the RI1 side and a dense vP layer on the inside. The dense layer has micropores with a pore size of about 0.025 tt or less on the inner surface, and the spongy tissue layer has cavities with a diameter of 1μ or more in volume ratio, along with the micropores that make up the sponge. 20% or more.

Incidentally, the hollow fiber of the present invention can also be obtained with a skin layer on the outer surface by appropriately changing the spinning conditions, and it goes without saying that such a structure is also possible.

<Examples> Examples of the present invention will be shown below, but the invention is not limited thereto.

Example 1 Using a Koka type flow tester, the mouthpiece was 1fiφXIQw.
+L.

17 parts of polyphenylene sulfide resin with a melt viscosity of 7900 voids measured at a temperature of 300°C and a shear rate of 200 sec, 10 parts of diethylene glycol, and 73 parts of N-methylpyrroline were uniformly melted at 250°C under pressure. This was used as a spinning stock solution.

The spinning stock solution was pushed out at 235° C. from the sheath of the sheath core type nozzle, and an internal coagulation solution containing 40 parts of diethylene glycol, 57 parts of N-methylpyrrolidone, and 3 parts of water was mixed was simultaneously pushed out from the core. After running 22wm in the air,
It was introduced into an external coagulating solution consisting of a 60% N-methylpyrrolidone solution in water, washed with water, and then wound up at a speed of 50 m/min. The obtained hollow fiber membrane has an inner diameter of 180 μm and an outer diameter of 250 μm.
μ, it has a dense layer with a thickness of about 0.25 μ inside, and in contact with this dense layer there is a sponge-like structure with a maximum pore diameter of 1.5 μ, and this sponge-like structure has a cavity with a diameter of 6 μ
It contained %.

This hollow m-fiber has a pressure of 60 kg/cJ.
It had a water permeation rate of 0006/d·Hr. Furthermore, the elimination rate of ovalbumin (molecular weight 45,000) at 500 ppH1 was 74% under a pressure of 2 kg/cJ.

Agent: Patent Attorney Katsutoshi Takahashi =11-

Claims (1)

[Claims] 1. It is made of polyphenylene sulfide resin and has a dense layer having micropores with a pore diameter of about 0.025μ or less on the inner surface,
A hollow fiber membrane having a layer made of a spongy silk fabric that is in contact with a dense layer of parentheses and contains about 20% or more by volume of cavities with a diameter of 1 p or more. 2. While extruding a solution containing polyphenylene sulfide resin from an annular nozzle, a coagulable bulk consisting of a mixture of a good solvent and a non-solvent of polyphenylene sulfide is introduced into the core bone of the annular nozzle, and then solidified. A method for producing a characteristic polyphenylene sulfide hollow fiber membrane. 3. The method according to claim 2, wherein the borophe macrodisulfide non-solvent in the coagulable liquid is a mixture of a polyhydric alcohol having 2 to 4 carbon atoms and water.