JPS618103A - Hydrophilic porous polyolefin hollow yarn - Google Patents

Abstract

PURPOSE:To obtain a porous polyolefin hollow yarn excellent in safety and operability and having permanent hydrophilicity imparted thereto even after the interruption of filtering, by forming an acrylonitrile or polyurethane resin film to the surfaces of the fibriles of a porous polyolefin hollow yarn. CONSTITUTION:A porous polyethylene hollow yarn, wherein minute voids formed by a large number of fibriles communicate the inner and outer wall surface of the hollow yarn, is prepared and an acrylonitrile or polyurethane resin is adhered to the surfaces of the fibriles of said hollow yarn. Subsequently, this resin coated hollow yarn is immersed in a coagulation bath and quick wet coagulation treatment is performed to form an acrylonitrile or polyurethane resin film which is, in turn, strongly adhered to the surfaces of fibriles to obtain a hydrophilic porous polyethylene hollow yarn.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to porous polyolefin hollow fibers with excellent hydrophilicity.

[Prior art]

Various membranes are known as ultrafiltration membranes and precision filtration membranes used for producing pure water, filtering colloidal substances in water, and the like.

In particular, membranes for medical, pharmaceutical, food, and precision industries are required to remove bacteria, and in particular, membranes that can also remove pyrogens are required for medical and pharmaceutical applications. . Although many membranes that can remove bacteria are known, there are no ultrafiltration membranes or microfiltration membranes that can simultaneously remove pyrogens.

Reverse osmosis is known as a method that can also remove pyrogens, but reverse osmosis requires high pressure.

Therefore, equipment costs are high, the equipment is large, and it is difficult to satisfy economic efficiency unless the processing capacity is increased.In addition, the method of storing treated water and using it little by little as needed Become. Even if various measures are taken to store water, there is a drawback that bacteria and pyrogens can contaminate the treated water.

In particular, porous membranes for water treatment, which have minute pores that can block bacteria, must be hydrophilic to allow water to pass through them.
Membranes made of hydrophilic materials tend to deteriorate when attacked by microorganisms, and there is also the problem that the concentration of bacteria increases on the side where they are attacked.

Previously, the present applicant solved the drawbacks of the conventional device in Japanese Patent Publication No. 56-52123 and Japanese Patent Application Laid-Open No. 57-42919, and achieved a structure with low equipment cost and energy cost.
As a membrane for precision filtration equipment that is simple, has few failures, and has high reliability, it is a porous polyolefin hollow fiber in which micropores with a pore diameter of 0.01 to 1 μm communicate between the inner wall surface and outer wall surface of the hollow fiber. I suggested thread. However, since this is a hydrophobic porous polyolefin hollow fiber, it is used by temporarily making it hydrophilic with alcohol etc. before use and replacing it with water. If the surface of the porous polyolefin hollow fiber is removed and dried by contacting with air, there is a problem that the freeness decreases, and there has been a strong demand for the development of a porous polyolefin hollow fiber with excellent hydrophilicity.

[Problem to be solved]

An object of the present invention is to provide a hydrophilized porous polyolefin hollow fiber that is safe and has excellent operability.

[Means to solve]

The L object of the present invention is that micropores formed between a large number of fibrils arranged approximately in the longitudinal direction of a hollow fiber are
A porous polyolefin hollow fiber that communicates between the inner wall surface and the outer wall surface of the hollow fiber, characterized in that a film made of an acrylonitrile-based or polyurethane-based resin is formed on the surface of the fibril. This is achieved by hydrophilic porous polyolefin hollow fibers.

A porous polyolefin hollow fiber in which micropores formed by a large number of fibrils communicate between the inner wall surface and the outer wall surface of the hollow fiber can be manufactured according to the above-mentioned Japanese Patent Application Laid-Open No. 57-42919. A method for obtaining permanently hydrophilized porous polyethylene hollow fibers by forming an acrylonitrile or polyurethane resin film on the surface of the fibrils forming such porous polyethylene hollow fibers is as follows:
After a solution containing an acrylonitrile-based or polyurethane-based resin is attached to the surface of the fibrils of porous polyethylene hollow fibers, these resins are immersed in a coagulant solution and subjected to rapid wet coagulation treatment to form an acrylonitrile-based or polyurethane resin. A system resin film can be formed and firmly attached to the surface of fibrils. In this case, when forming an acrylonitrile-based porous membrane, the acrylonitrile resin used contains 30% by weight of acrylonitrile.
If a polymer having an acrylonitrile content of less than 30% by weight is used, the hydrophilicity of the acrylonitrile-based film becomes undesirable. As the acrylonitrile resin, an acrylonitrile homopolymer or a copolymer of acrylonitrile and vinyl acetate, methyl acrylate, methyl methacrylate, vinyl chloride, acrylamide, etc. is preferably used.

When forming a polyurethane resin film, a known resin may be used, such as a condensation polymer of aliphatic polyether or polyester having active hydrogen such as a hydroxyl group or a carboxyl group at the terminal and a diisocyanate. .

These acrylonitrile-based or polyurethane-based resin films are adhered as uniformly as possible to the surface of the fibrils of the porous hollow fibers, and the amount of adhesion is kept to a minimum, thereby minimizing clogging of the open pores of the hollow fibers due to adhesion treatment. It is preferable.

Acrylonitrile-based films and polyurethane-based films exhibit excellent hydrophilicity. Therefore, a porous polyolefin hollow fiber having an acrylonitrile or polyurethane membrane adhered to the fibril surface exhibits excellent hydrophilicity.

In order to manufacture a module using the hydrophilic porous polyolefin hollow fiber of the present invention, it is sufficient to apply the general known module manufacturing method using porous hollow fiber as is, from the outer wall side of the porous hollow fiber to the inner wall side. Any form of module may be used as long as it filters liquid or gas from the side or from the inner wall to the outer wall. By using the hydrophilized porous polyolefin hollow fiber of the present invention, it is possible to remove colloidal substances, bacteria, and pyrogenic substances,
In addition to always maintaining safe operability, equipment costs and costs are reduced compared to conventional equipment.
The energy cost is low, the structure is simple, there are few failures, and highly reliable precision filtration is possible.

〔Example〕

Hereinafter, the present invention will be explained by examples.

Example 1 1 part by weight of a powdered acrylonitrile-based copolymer consisting of 93% by weight of acrylonitrile and 7% by weight of vinyl acetate was dissolved in 99 parts by weight of dimethyl thylformamide at 25°C.
A porous polyethylene hollow fiber (manufactured by Mitsubishi Rayon, trade name EHF) was immersed in the solution, and then squeezed to make the amount of solution attached to the hollow fiber 80% owf, and then heated at 60°C.
The acrylonitrile copolymer is immersed in hot water to make it porous by rapid solidification and to remove the solvent.Then, the acrylonitrile copolymer is thoroughly washed with water and dried, and an acrylonitrile film is applied to the surface of the fibrils of the hollow fibers. was formed to obtain hydrophilized porous polyethylene hollow fibers.

A module is preferably used in which 100 of these hydrophilized porous polyethylene hollow fibers are bundled in a U-shape, the opening for the hollow fibers is hardened with resin, and the length of the resin-embedded part is 4 cm and the effective length of the hollow fibers is IQ cm.

25°C from the outside of this hydrophilized porous polyethylene hollow fiber.
of ethanol to impregnate the inside of the porous polyethylene hollow fiber, and then apply pressure of 3.5 mL from the outside of the hollow fiber.
After filtering the water of 51 under 80 mHg, the water was extracted and
After the outside of the hollow fiber was brought into contact with air for a period of time, water was again filtered from the outside of the hollow fiber under a pressure of 3801 mHH. As a result, the module using the hydrophilized porous polyethylene hollow fiber of the present invention did not notice any change in the filtration rate. I couldn't.

Comparative Example 1 A normal module was prepared in the same manner as in Example 1 using the porous polyethylene hollow fibers that had not been subjected to the hydrophilic treatment, and a filtration experiment was conducted in the same manner as in Example 1. A module using this untreated porous polyethylene hollow fiber had a 32% reduction in filtration rate after 5 hours of contact with air.

Example 2 Polyester synthesized from adipic acid and 1-4 butanediol (molecules it 1500) 10000 weight 4
29 parts by weight of -4' diphenylmethane diisocyanate was added, and the mixture was reacted at 80° C. for 3 hours under a nitrogen stream to obtain polyurethane. The same porous polyethylene hollow fiber as used in Example 1 was immersed in a 25"C solution prepared by dissolving 0.5 parts by weight of this polyurethane in 99.5 parts by weight of dimethylformamide, and the hollow fiber was squeezed. The adhesion amount of the solution was set to 330% owf, and the solution was subsequently immersed in water at 60°C to make the polyurethane porous by rapid coagulation and to remove the solvent. After that, it was thoroughly washed with water and dried to form hollow fiber fibrils. A hydrophilic porous polyethylene hollow fiber was obtained with a polyurethane film fixed to the surface of the fiber.100 of the hydrophilic porous polyethylene hollow fibers were bundled into a U-shape, the opening for the hollow fiber was hardened with resin, and the resin-embedded part was A module with a length of 4 cm and a hollow fiber effective length IQcn+ was created.

25° from the outside of this hydrophilic porous polyethylene hollow fiber
After adding ethanol C to impregnate the inside of the porous polyethylene hollow fiber with ethanol, 5β water was filtered from the outside of the hollow fiber under a pressure of 380++ mHg, the water was extracted, and the outside of the hollow fiber was filtered for 5 hours. After contact with air, the water was again filtered from the outside of the hollow fiber under a pressure of 380 i11 (g), and no change in filtration rate was observed.

This l≧”λ As in Comparative Example 1, a normal module was prepared in the same manner as in Example 2 using porous polyethylene hollow fibers that had not been subjected to hydrophilic treatment. The filtration rate of the module using this untreated porous polyethylene hollow fiber decreased by 32% after 5 hours of contact with air.

〔Effect of the invention〕

The hollow fiber module using the hydrophilic porous polyolefin hollow fibers of the present invention is capable of repeating filtration with stable reliability without decreasing the filtration rate even after filtration is interrupted and the hollow fibers are brought into contact with air. I can do it.

Claims (1)

[Claims] 1. A porous polyolefin hollow fiber in which micropores formed between a large number of fibrils arranged substantially in the longitudinal direction of the hollow fiber communicate between the inner wall surface and the outer wall surface of the hollow fiber. , a hydrophilic porous polyolefin hollow fiber characterized in that a membrane made of acrylonitrile or polyurethane resin is formed on the surface of the fibrils.