JPH0644978B2 - Method for producing hollow fiber semipermeable membrane - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a hollow fiber-shaped semipermeable membrane.

[Conventional technology]

In the hollow fiber semipermeable membrane, conventionally, a stock solution containing a polymer, a solvent and various additives is sent to an annular nozzle by a gear pump, pure water is discharged from the center with the stock solution to the outside, and then a gelled polymer in a coagulation bath is discharged. Further, the hollow fiber is washed with water to produce a hollow fiber semipermeable membrane in which pure water is enclosed in the hollow fiber. The hollow fiber semipermeable membrane is made into a module by applying a drying inhibitor such as glycerin on the inner and outer surfaces, and then drying and adhering. However, in the conventional method of injecting and coating the aqueous solution of the anti-drying agent on the inner surface of the hollow fiber-shaped semipermeable membrane by water pressure,
As the inner diameter of the hollow fiber semipermeable membrane becomes smaller, it becomes more difficult to inject a highly viscous solution such as an aqueous glycerin solution. If it is injected into the interior by the conventional method, the water pressure is increased according to the viscosity of the anti-drying agent, heating is carried out, and a treatment time of several hours is required.

[Problems to be solved by the invention]

The present invention provides a method for producing a hollow fiber-like semipermeable membrane accompanied by a drying prevention treatment.

[Means for solving problems]

The present inventors have paid attention to the fact that the hollow fiber-shaped semipermeable membrane is manufactured in a state in which a liquid is sealed inside, and as a result of intensive studies, as a result, an anti-drying agent was added inside the hollow fiber-shaped semipermeable membrane in the spinning step. The manufacturing method of encapsulation was found, and the present invention was completed.

That is, the present invention is a hollow fiber semipermeable membrane characterized by comprising injecting an aqueous solution containing a drying inhibitor into a hollow fiber semipermeable membrane in a spinning step and then contacting the solution with an antidrying agent. It is a manufacturing method.

The configuration of the present invention will be described in detail below.

As a hollow fiber semipermeable membrane, any pore size, yarn diameter and material can be applied as long as it can be wet-spun, and as a drying inhibitor, it is non-volatile and easily dissolved in water.
Any washable substance may be used, and from the viewpoint of viscosity and handleability, a polyhydric alcohol aqueous solution is preferable, and glycerin, dipropylene glycol, tripropylene glycol, polypropylene glycol and tetraethylene glycol are more preferable.

In order to produce the hollow fiber semipermeable membrane of the present invention, first, the polyhydric alcohol is dissolved in pure water from which fine particles and the like have been removed beforehand by a filter, and the amount is 5 to 50 wt%, preferably 10 to 30 wt%.
Adjust to the concentration of. If the concentration is 5 wt% or less, the entire surface of the hollow fiber semipermeable membrane is not covered, so that the recovery rate of the amount of water permeation after drying is reduced to 20% or less. Also, 50 wt%
In the above case, since the viscosity is high, yarn breakage occurs during spinning, and the physical properties of the film are also affected. Next, the solution is discharged from the annular nozzle at a constant rate by a metering pump and enclosed in the hollow fiber semipermeable membrane. By immersing the hollow fiber-shaped semipermeable membrane thus obtained in a polyhydric alcohol aqueous solution for a short period of time at room temperature, the hollow fiber-shaped semipermeable membrane recovers 70% or more in water permeability even after drying.

〔Example〕

 Examples will be shown below.

Example 1 As a drying inhibitor, 2 to 70 wt% of glycerin, diethylene glycol and tetraethylene glycol aqueous solution was used and spun in the same manner as in Example 1 of JP-A-58-156018, and the same solution as the drying inhibitor was added at room temperature. Soak for 30 minutes, 5
After drying at 0 ° C. for 2 hours, the recovery rate of water permeability was examined. The results are shown in FIG. 5 wt% as shown in Fig. 1
Since the recovery rate of water permeability is maximum and shows the value peculiar to each solution, a hollow fiber semipermeable membrane is manufactured by the same method as above using a 30 wt% aqueous solution of polyhydric alcohol shown in Table 1.
The water permeability recovery property of each was evaluated. The results are shown in Table 1.

The hollow fiber semipermeable membrane used was polysulfone, and the thread diameter was 0.4 mm in inner diameter and 0.8 mm in outer diameter.

Comparative Example 1 A polysulfone hollow fiber semipermeable membrane in which pure water was enclosed during spinning was spun in the same manner as in Example 1, immersed in a 30 wt% glycerin aqueous solution at room temperature for 30 minutes, dried at 50 ° C. for 2 hours, and then permeable to water. The recovery rate of quantity was investigated. As a result, the water permeability recovery rate was about 20%.

[Effect of the present invention]

The hollow fiber-shaped semipermeable membrane obtained by the method of the present invention can be treated by a very simple method of immersing in a drying inhibitor at room temperature for about 1/10 of the time, and further, regardless of form and material, all It has an advantage that the hollow fiber semipermeable membrane can be dried.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the concentration of glycerin, tetraethylene glycol, diethylene glycol and the water permeation recovery rate in Example 1 of the present invention.

Claims (4)

[Claims] 1. A method for producing a hollow fiber semipermeable membrane, which comprises injecting an aqueous solution containing an anti-drying agent into a hollow fiber semipermeable membrane in a spinning step and then bringing the hollow fiber semipermeable membrane into contact with the aqueous solution containing the antidrying agent. Method. 2. The method for producing a hollow fiber semipermeable membrane according to claim 1, wherein a polysulfone, polyacrylonitrile, polyamide, polyimide and polyethersulfone hollow fiber semipermeable membrane is used as the hollow fiber semipermeable membrane. 3. The method for producing a hollow fiber semipermeable membrane according to claim 1, wherein a polyhydric alcohol is used as a drying inhibitor. 4. The method for producing a hollow fiber semipermeable membrane according to claim 3, wherein glycerin, dipropylene glycol, tripropylene glycol, polypropylene glycol and tetraethylene glycol are used as the polyhydric alcohol.