JP2009195764A - Method of manufacturing hollow fiber separation membrane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a hollow fiber separation membrane having high water permeability and being resistant to fiber breaking. <P>SOLUTION: The manufacturing method uses a triple-tube nozzle 1 and comprises discharging, from a middle nozzle 3, a high-temperature polymer solution obtained by dissolving a polymer in a solvent at high temperatures, discharging a solution of an agent for formation of hollow portions from an inside nozzle 2 and discharging a solution of a hole-forming agent from an outside nozzle 4 so as to carry out spinning and cooling to cause phase separation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a hollow fiber separation membrane that can be used for water purification treatment and the like.

  As a method for making the membrane porous, there are a porogen method, a non-solvent induced phase separation method, and the like, but it is difficult to produce a uniform porous membrane by these methods. As an alternative method, a thermally induced phase separation method (TIPS method) is known. The thermally induced phase separation method is a method in which a polymer is made porous by dissolving in a solvent at a high temperature and cooling the polymer solution to cause phase separation.

Patent Document 1 describes an invention for obtaining a film-like porous membrane by casting using a heat-induced phase separation method, but there is no description about obtaining a hollow fiber membrane. Patent Documents 2 and 3 describe that a hollow fiber membrane is obtained using a triple tube nozzle.
JP 2003-17074 A JP-A-2-290229 Japanese Examined Patent Publication No. 7-98136

  This invention makes it a subject to provide the manufacturing method of the hollow fiber separation membrane from which the water permeability performance is good and the thing which is hard to disconnect is obtained.

The present invention is a method for producing a hollow fiber separation membrane using a triple tube nozzle,
A polymer solution in a high-temperature state obtained by dissolving in a solvent is discharged from an intermediate nozzle, a hollow portion forming agent liquid is discharged from an inner nozzle, a hole forming agent solution is discharged from an outer nozzle, and then phase separation is performed by cooling. A method for producing a hollow fiber separation membrane is provided.

  According to the production method of the present invention, by using a thermally induced phase separation method and using a triple tube nozzle, it is possible to obtain a hollow fiber separation membrane having high water permeability and difficult to break yarn.

  The polymer solution used for spinning in the production method of the present invention can be obtained by dissolving a mixture of a film-forming polymer and a high-boiling solvent at a temperature lower than the boiling point of the high-boiling solvent and above the binodal temperature. The binodal temperature refers to a liquid phase (one phase) region of a thermodynamically homogeneous mixture solution melted at a high temperature when a film-forming polymer is mixed with a high boiling point solvent, a concentrated phase and a diluted phase of a cellulose derivative. The temperature at the boundary of the two-phase region consisting of

  The film-forming polymer is not particularly limited, and examples thereof include cellulose derivatives such as cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate, and may be a copolymer thereof.

  The high boiling point solvent preferably has a boiling point of 100 ° C. or higher, and includes 2-methyl-2,4-pentanediol (boiling point 197 ° C.), 2-ethyl-1,3-hexanediol (boiling point 245 ° C.) and the like. Can do.

  The dissolution temperature is equal to or higher than the binodal temperature of the solvent, preferably within a temperature range higher by 50 ° C. than the binodal temperature, and more preferably within a temperature range higher by 30 ° C. from the binodal temperature.

  Examples of the hollow part forming agent solution used for spinning in the production method of the present invention include 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, and the like.

  As the pore-forming agent solution used for spinning in the production method of the present invention, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, N-methyl-2-pyrrolidone, polyethylene glycol Etc.

  In the production method of the present invention, a spinning triple tube nozzle having a schematic structure as shown in FIG. 1 is used. FIG. 1 is a longitudinal sectional view of the triple tube nozzle 1.

  The triple tube nozzle 1 has three nozzles, an inner nozzle 2, an intermediate nozzle 3, and an outer nozzle 4, and the three nozzles form concentric circles. When spinning, a polymer solution in a high temperature state is discharged from the intermediate nozzle 3, and in parallel therewith, the hollow portion forming agent liquid is discharged from the inner nozzle 2 and the hole forming agent solution is discharged from the outer nozzle 4. The winding speed at this time is preferably about 20 to 40 m / min.

  After spinning using a triple pipe nozzle in this way, preferably after passing through the air, it is led into a water bath or warm water bath and cooled. This cooling causes liquid-liquid phase separation and phase separation from one phase (mixed solution phase) to two phases (a concentrated phase and a diluted phase of the film-forming polymer solution).

  The cooling is performed from the temperature immediately after spinning to a temperature that is preferably 50 to 200 ° C lower, more preferably 70 to 150 ° C lower.

  Thereafter, the remaining high-boiling point solvent is removed by liquid-liquid extraction using another solvent such as water, room temperature under reduced pressure, or heat drying to obtain a hollow fiber separation membrane.

(1) Pure water permeation performance A hollow fiber separation membrane having an effective length of 50 cm is subjected to a water pressure of 0.1 MPa with pure water at 25 ° C. from the inside to measure the amount of pure water permeated per unit time. The bundle was determined by dividing by the membrane area based on the inner surface area.

(2) Tensile strength at break and tensile elongation Using a tensile tester (EZTest, Shimadzu Corp.), pulling a hollow fiber separation membrane with an effective length of 5 cm at a crosshead speed of 10 mm / min. It was measured.

Example 1
A mixture of 30% by mass of cellulose acetate butyrate and 70% by mass of 2-methyl-2,4-pentanediol was dissolved by heating at 180 ° C. to obtain a polymer solution. This polymer solution was discharged from an intermediate nozzle of a triple tube nozzle, and in parallel, 2-methyl-2,4-pentanediol was discharged from an inner nozzle and an outer nozzle, and spinning was performed at a winding speed of 40 m / min.

  After passing through the air for 1 second, it is guided in a hot water bath at 40 ° C., cooled, phase-separated, immersed in water for desolvation, and hollow fiber separation with an inner diameter of 0.8 mm and an outer diameter of 1.3 mm A membrane was obtained.

Example 2
A hollow fiber separation membrane having the same dimensions was obtained in the same manner as in Example 1 except that polyethylene glycol (average molecular weight 200) was discharged from the outer nozzle.

Example 3
A hollow fiber separation membrane having the same dimensions was obtained in the same manner as in Example 1 except that N-methyl-2-pyrrolidone was discharged from the outer nozzle.

Comparative Example 1
A hollow fiber separation membrane having the same dimensions was obtained in the same manner as in Example 1 except that nothing was discharged from the outer nozzle.

The longitudinal cross-sectional view of the triple tube nozzle used by this invention.

Claims (1)

A method for producing a hollow fiber separation membrane using a triple tube nozzle,
A polymer solution in a high-temperature state obtained by dissolving in a solvent is discharged from an intermediate nozzle, a hollow portion forming agent liquid is discharged from an inner nozzle, a hole forming agent solution is discharged from an outer nozzle, and then phase separation is performed by cooling. A method for producing a hollow fiber separation membrane.

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