JP2002177748A - Method for treating porous organic hollow fiber membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating a porous organic hollow fiber membrane by which the drying of the treated membrane can be carried out in a comparatively short time and the elongation of the membrane after dried can be enhanced. SOLUTION: The porous organic hollow fiber membrane is immersed in alcohol solution of glycerin and dried.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for treating a porous organic hollow fiber membrane. More specifically, the present invention relates to a method for treating a porous organic hollow fiber membrane capable of increasing elongation after drying.

[0002]

2. Description of the Related Art It has been proposed to improve the mechanical strength of a porous organic hollow fiber membrane by heat-treating it in glycerin at 60 ° C. or higher (Japanese Patent Laid-Open No. 61-9861). Such a treatment method has a drawback that it takes a long time for drying due to the effect of the water retention capacity of glycerin attached to the membrane. In addition, when glycerin is used as an aqueous solution, there is also a problem that it takes a long time to completely penetrate the glycerin aqueous solution into the inside of the membrane.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for treating a porous organic hollow fiber membrane in which drying is performed in a relatively short time and elongation after drying can be increased.

[0004]

In order to achieve the object of the present invention, a method for treating a porous organic hollow fiber membrane comprises immersing the porous organic hollow fiber membrane in an alcohol solution of glycerin,
It is performed by drying.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As a porous organic hollow fiber membrane, a material obtained by wet-spinning or dry-wet spinning from an organic substance such as polysulfone, polyamide or cellulose is used. These hollow fiber membranes can be used in a wet state or a dry state immediately after spinning. When used in a dry state, for example, hollow fiber membranes cut to a certain length can be subjected to treatment in a bundled state. To bundle the hollow fiber membrane group, bind both ends with rubber bands or adhesive tape, weld the end surface with a hot plate, a hot wire, etc., or wrap the entire hollow fiber membrane group with paper, nonwoven fabric, etc. It is performed by the method described above.

The alcohol solution of glycerin used in the treatment must have a concentration of 3 to 10% by weight, preferably 3 to 5% by weight. If the concentration is lower than this, the desired treatment effect cannot be obtained, while if the concentration is higher than this, sticking or the like occurs between the hollow fiber membranes.

The immersion treatment with an alcohol solution of glycerin is carried out at a temperature lower than the boiling point of ethanol used as a preferred alcohol, generally at room temperature for about 5 to 60 seconds, followed by drying at about 30 to 60 ° C. Is
About 0.5 to 3 hours is sufficient for the time required for drying.

[0008]

According to the method of the present invention, the drying time after the immersion treatment for improving the elongation can be greatly reduced, and the elongation can be significantly improved. In addition, the wettability and permeability of glycerin, whose viscosity has been reduced by alcohol, to the hollow fiber membrane are also improved, which contributes to the improvement of elongation.

[0009]

Next, the present invention will be described by way of examples.

EXAMPLE A porous polysulfone hollow fiber membrane produced by a dry-wet spinning method
(Outer diameter 300 μm, inner diameter 200 μm) cut to a length of 30 cm 10
000 pieces, 10% in 5% by weight glycerin ethanol solution
After immersion for 2 seconds and drying in a drier at 50 ° C., drying was completed in 2 hours and no sticking was observed between the hollow fiber membranes.

With respect to one hollow fiber membrane thus dipped and dried, the elongation at the time of tensile cutting at an initial length of 50 mm and a tensile speed of 10 mm / min was 60%.

COMPARATIVE EXAMPLE 1 In the example, when the immersion treatment was not performed, some fixation was observed between the hollow fiber membranes, and the elongation of the hollow fiber membrane was 23%.

Comparative Example 2 In the example, when immersion was performed for 10 seconds in a 5% by weight glycerin aqueous solution and then drying was performed at 50 ° C., drying required 15 hours. No fixation was observed between the hollow fiber membranes, but the elongation of the hollow fiber membrane was 30%.

Comparative Example 3 In the example, when immersed in ethanol for 10 seconds and then dried at 50 ° C., the drying was performed in 2 hours and no sticking was observed between the hollow fiber membranes. 24% elongation
Met.

Claims (3)

[Claims] 1. A method for treating a porous organic hollow fiber membrane, comprising immersing the porous organic hollow fiber membrane in an alcohol solution of glycerin and drying. 2. The method for treating a porous organic hollow fiber membrane according to claim 1, wherein an alcohol solution of glycerin of 3 to 10% by weight is used. 3. The method for treating a porous organic hollow fiber membrane according to claim 1, wherein the porous organic hollow fiber membrane is immersed as a bundle and dried.