JP2000325759A - Manufacture of membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and securely protect a membrane from being dried during a manufacturing process by immersing the membrane into a trehalose water solution and retaining the moisture of the membrane in the case of manufacturing the membrane used for filtration or the like. SOLUTION: A membrane manufacturing raw stock solution as a core liquid is discharged from, for example, an orifice type double cylindrical cap and passed through the given dry length, and then introduced into a solidifying medium to form hollow yarns. Also the hollow fibers are introduced into a cleaning bath and cleaned therein and then introduced into a trehalose water solution bath of given concentration to manufacture moisture-retaining hollow fibers. The moisture-retaining hollow yarns are dried by a drier, and then hollow separating membranes 4 are boundled, and both terminals of a bundle are fixed on a glass tube module case 5 by a potting agent 2 to manufacture a mini- module. Then γ rays are emitted to the mini-module in the wet state, and then its blood inlet 1 is connected with a dialyzate outlet 6, and distilled water is made to flow out of a blood outlet 7 to clean the hollow yarns and the interior of the module, and water permeability and the β2 micro-globulin removing performance are measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a membrane, characterized in that the membrane is kept moist with an aqueous trehalose solution.

[0002]

2. Description of the Related Art Conventionally, membranes used in filtration and dialysis treatments are often immersed in an aqueous glycerin solution to prevent the permeability of the membrane from decreasing during drying. Has been prevented. However, although glycerin has low toxicity, when the membrane is used for medical treatment such as dialysis, it is necessary to wash and remove glycerin during the manufacturing process so that it does not directly enter the body.

Furthermore, if a step of immersing an aqueous glycerin solution into a membrane is introduced, the aqueous glycerin solution adheres to the manufacturing equipment and the floor surface at the manufacturing site, and the foot slips extremely when the aqueous glycerin aqueous solution flows out to the floor surface. This is a dangerous work, and cleaning work is frequently performed in order to ensure safety. Further, in a step where manual work is performed, the hand or the film itself becomes sticky, and it cannot be said that the work is easy.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to improve the disadvantages of the prior art and to provide a method for producing a membrane characterized by moisturizing the membrane with an aqueous trehalose solution.

[0005]

In order to solve the above-mentioned problems, the present invention has the following arrangement. "A method for producing a membrane, comprising a step of humidifying the membrane by immersing it in an aqueous trehalose solution."

[0006]

DETAILED DESCRIPTION OF THE INVENTION Trehalose used in the present invention is one of disaccharides having a molecular weight of 342.31 and has a structure in which two molecules of D-glucose are linked together by their reducing groups. In its binding mode, there are three types of isomers of natural α, α-bond, α, β-bond, β, and β-bond, and any of them can be used in the present invention. Trehalose is a compound safe for living organisms, which has already been used in food applications such as cosmetics and sweeteners and as a pharmaceutical. Glycerin, which has been conventionally used, shows symptoms such as kidney disease when taken at a high concentration.Thus, when glycerin is used as a humectant, it is necessary to thoroughly clean the membrane, whereas trehalose Has the feature that it is not necessary.

[0007] The solubility of trehalose in water at room temperature is about 40% by weight. If the temperature of water is increased, it is possible to prepare a trehalose aqueous solution having a higher concentration. However, if the concentration is higher than 60% by weight, a large amount of trehalose crystals are formed when the film after moisturizing is placed at room temperature. Precipitate out,
The concentration of the aqueous trehalose solution as a humectant is desirably 60% by weight or less, since the film tends to be damaged or deposited in the working environment. When the concentration is less than 1% by weight, the moisturizing effect of the film tends to be low. Therefore, the concentration of the trehalose aqueous solution as a humectant is desirably 1% by weight or more. However,
When glycerin is used as a moisturizer, the concentration is 10%
When the value is less than 1, the performance becomes remarkable, but in the case of the trehalose aqueous solution, the performance is maintained even at 1%. Therefore, when used at a humectant concentration of 1%, it is very advantageous in terms of cost.

Further, the aqueous glycerin solution as a moisturizing agent is attached to a manufacturing apparatus or a floor surface at a manufacturing site, and particularly when the aqueous glycerin solution flows out to the floor surface, the feet are very slippery and dangerous work is performed. In order to ensure safety, cleaning work is frequently performed, which is not preferable in terms of work. Further, in a step where manual work is performed, the hand or the film itself becomes sticky, and it cannot be said that the work is easy. On the other hand, the trehalose aqueous solution is smooth, does not slip even when it flows to the floor, and precipitates as crystals when left to stand for easy cleaning.

The difference in viscosity between the glycerin aqueous solution and the trehalose aqueous solution is considered to affect the washing efficiency, and it is considered that the use of the trehalose aqueous solution can greatly reduce the washing time.

[0010] In addition, the glycerin aqueous solution is not suitable for a case where a clean production site such as a medical material is required, since the bacterium is easily propagated as used when cultivating the bacterium. On the other hand, as trehalose has low texture for food use, it is difficult for bacteria to adhere,
Suitable for use in medical material production environments.

The form of the membrane used in the present invention may be any form such as a hollow fiber membrane, a flat membrane, or a microcapsule membrane.

The membrane used in the present invention is made of polyethylene, polypropylene, polycarbonate, polyacrylonitrile, polysulfone, polyester, poly2
The main materials include vinylidene fluoride, poly (vinylidene tetrafluoride), polymethyl methacrylate, cellulose triacetate, and ethylene vinyl alcohol, but are not limited in nature.

The method for producing a membrane of the present invention will be described by taking a hollow fiber membrane as an example. In manufacturing the membrane, the membrane is immersed in a bath of an aqueous solution containing a humectant after washing with water. The hollow fiber is stored after subjecting an excess aqueous solution of the humectant to a treatment such as dewatering or drying. Thereafter, the hollow fiber membranes are bundled, and both ends are fixed to the module case with a potting agent so as not to block the hollow portion of the hollow fiber. At this time, if there is no humectant, the hollow fiber is dried, and the performance is reduced.

Further, the membrane obtained by the present invention is used for the production of various separation membranes including dialysis membranes, and is particularly suitable for the production of polysulfone hollow fiber membranes. It is also used for applications such as artificial kidneys, water treatment membranes, and gas separation membranes.

[0015]

EXAMPLES The measuring methods used are as follows. (1) Water permeability In the case of a hollow fiber, insert the hollow fiber membrane into a case having holes for reflux liquid at both ends, prepare a module using a commercially available epoxy adhesive, and maintain the module at 37 ° C. Water permeation performance was measured by applying water pressure to the inside of the hollow fiber and calculating from the amount of water permeating through the membrane for a certain period of time, the effective membrane area, and the pressure difference between the membranes. (2) Measurement of β2 microglobulin removal performance 30 ml of bovine serum filtered with 0.45 μm filter
Then, human β2 microglobulin was dissolved at a concentration of 5 mg / ml, refluxed at 1 ml / min to the hollow fiber hollow portion from the blood inlet of the washed mini-module, and phosphoric acid kept at 37 ° C. was placed outside the hollow fiber. 140 ml of buffer (pH 7.5)
Was refluxed in a closed system at a rate of 20 ml / min. After refluxing for 2 hours, the reflux liquid inside and outside the hollow fiber was collected, and the clearance was calculated. The clearance was calculated by equation (1).

[0016]

(Equation 1)

Here, CL: clearance (ml / mi)
n), CBi: concentration at the module inlet side (mg / mi)
n), CBo: concentration at the module outlet side, QB: module supply liquid amount (ml / min).

Hereinafter, "parts" means "parts by weight".

(Examples 1 to 3, Comparative Examples 1 and 2) 18 parts of polysulfone (Udel P-3500) and 9 parts of polyvinylpyrrolidone (K30) were added to 72 parts of N, N-dimethylacetamide and 1 part of water. It melt | dissolved by heating at 14 degreeC.
This film forming stock solution was discharged from an orifice-type double cylindrical die having an outer diameter of 0.3 mm and an inner diameter of 0.2 mm, and a solution composed of 58 parts of dimethylacetamide and 42 parts of water was discharged as a core liquid, and passed through a dry length of 350 mm. Thereafter, the mixture was led to a coagulation bath containing 100% water to obtain a hollow fiber. The obtained hollow fiber was led to a water washing bath at 85 ° C. while being on-line, washed with water, and then led to a trehalose aqueous solution bath having a predetermined concentration to obtain a moisturized hollow fiber.

After the moisturized hollow fiber is dried overnight in a dryer at 50 ° C., 20 polysulfone hollow fiber separation membranes are bundled, and both ends are epoxy-potted so as not to block the hollow portion of the hollow fiber. It is fixed to a glass tube module case to make the mini module shown in FIG.
Irradiation was performed. The mini-module has a diameter of about 7 mm and a length of about 10 cm.

After the γ-ray irradiation, the blood inlet of the mini-module is connected to the dialysate outlet by a silicon tube, and distilled water is flowed from the blood outlet at a flow rate of 1 ml / min for 30 minutes to wash the hollow fiber and the inside of the module. Water permeability and β2 microglobulin removal performance were measured. Table 1 shows the results.

The obtained bundle of hollow fibers was easy to handle without stickiness.

(Comparative Examples 3 and 4) 18 parts of polysulfone (Udel P-3500) and polyvinylpyrrolidone (K3
0) 9 parts of N, N-dimethylacetamide 72 parts, water 1
And heated and dissolved at 90 ° C. for 14 hours. This membrane-forming stock solution was discharged from an orifice-type double cylindrical die having an outer diameter of 0.3 mm and an inner diameter of 0.2 mm, and a solution composed of 58 parts of dimethylacetamide and 42 parts of water was discharged as a core liquid.
After passing through 0 mm, it was led to a coagulation bath of 100% water to obtain a hollow fiber. The obtained hollow fiber was led to a water washing bath at 85 ° C. while being on-line, washed with water, and then led to a glycerin aqueous solution bath having a predetermined concentration to obtain a moisturized hollow fiber.

After the moisturized hollow fiber is dried overnight in a dryer at 50 ° C., 20 polysulfone hollow fiber separation membranes are bundled, and both ends are epoxy-potted with an epoxy potting agent so as not to block the hollow portion of the hollow fiber. It is fixed to a glass tube module case to make the mini module shown in FIG.
Irradiation was performed. The mini-module has a diameter of about 7 mm and a length of about 10 cm.

After the γ-ray irradiation, the blood inlet of the mini-module is connected to the dialysate outlet by a silicon tube, and 500 ml of distilled water is flowed from the blood outlet at a flow rate of 100 ml / min to wash the hollow fiber and the inside of the module to allow water permeation. Gender and β
2 Measurement of microglobulin removal performance was performed. Table 1 shows the results.

The obtained bundle of hollow fibers was sticky and could not be said to be easy to handle.

[0027]

[Table 1]

[0028]

According to the method for producing a film of the present invention, it is possible to provide a film excellent in handleability without deteriorating the performance of the film. Furthermore, by using the trehalose aqueous solution, a working environment is improved, and a method for producing a film having excellent cleaning efficiency is provided.

[Brief description of the drawings]

FIG. 1 is a schematic view of a mini-module used in Examples of the present invention and Comparative Examples.

[Explanation of Codes] Blood inlet 2. Potting section 3. 3. Dialysate inlet 4. Hollow fiber separation membrane Glass tube module case 6. 6. Dialysate inlet Blood outlet 8. Module header 9. Module case

Continued on the front page F-term (reference) 4D006 GA13 HA02 HA18 MA01 MB02 MB06 MC18 MC22 MC23 MC29 MC34 MC37 MC39 MC40X MC48 MC49 MC62X NA04 NA58 NA64 NA71 PB09 PC44 PC47

Claims (5)

[Claims] 1. A method for producing a film, comprising the step of immersing the film in a trehalose aqueous solution to keep the film moist. 2. A method for producing a membrane, wherein the concentration of the trehalose aqueous solution according to claim 1 is 1 to 60% by weight. 3. The method according to claim 1, wherein the form of the membrane is a hollow fiber membrane. 4. The method according to claim 1, wherein the material of the membrane is a polysulfone resin. 5. A method for producing a membrane, wherein the membrane is used for dialysis.