JPH0211294B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for modularizing a separation membrane. For more details, when converting into a module,
This invention relates to a method for drying a membrane portion to be sealed. Separation membranes, such as hollow fiber blood separation membranes, are used in various medical applications such as artificial kidneys, hemofiltration, and cell separation. Generally, in treatment using an artificial kidney, blood from a vein in the arm is passed through this hollow fiber blood separation membrane, and dialysate is passed outside the separation membrane. Due to the difference in osmotic pressure between blood flow and dialysate through the membrane, urea, uric acid,
It removes waste products such as creatinine. Furthermore, the dialysate contains various electrolytes to maintain the electrolyte balance of the blood or to remove excess water from the body. These hollow fiber dialyzers are made by bundling a large number of hollow fibers, placing them in a plastic tube, and sealing the terminals with urethane resin.
It's modular. There are two methods for sealing the terminal with resin: dip method and rotational molding method. The dip method involves putting an appropriate amount of resin into a cup and attaching the ends of the hollow fibers to the resin. Leave the hollow fiber as it is until the resin hardens, then take it out from the cup and cut off the tip. Repeat this method on one side at a time to seal both ends. This dip-type hollow fiber end sealing method has drawbacks such as a long time required and a lack of precision in gluing. On the other hand, in the rotational molding method, a bundle of hollow fibers is packed into a cylindrical plastic capsule. Insert a tube with a nozzle led from the resin reservoir into this capsule. This capsule at 400rpm
Generally, the capsule is rotated at a rotation speed of about 1,200 rpm, and the centrifugal force causes the pulp ejected from the nozzle to be blown to the end of the capsule and harden, thereby sealing the end of the hollow fiber. On the other hand, there are two types of hollow fiber: wet type and dry type. Wet types include membranes made of polymethyl methacrylate, ethylene-vinyl acetate copolymer, polysulfone, and the like. Semipermeable membranes of these synthetic polymers are formed by a wet method in which a polymer solution is coagulated in a non-solvent such as water. In the most common case of water coagulation, during the film formation process, the polymer solution undergoes microphase separation into coacervate droplets and a matrix phase due to solvent evaporation or interdiffusion between the solvent and water. A sol-to-gel transition occurs in this state. At this time, the coacervate droplets become pores and a porous membrane is formed. By the way, wet membranes need to be constantly moistened with water to maintain their gel state. On the other hand, the ends of the hollow fibers must be dried to prevent foaming of the urthane resin used for sealing. Drying methods include hot air drying using a hair dryer, drying using a thermostat,
There are methods to remove water using centrifugal force. With these drying methods, it is very difficult to dry only the ends of the hollow fibers, which may reduce the performance of the membrane. Therefore, after careful consideration, the inventors found that
We have now invented a new drying method that solves these problems. The present invention focuses on microwaves and is a method of irradiating hollow fibers immersed in water or the like with microwaves and drying only the irradiated portions. In addition, drying by microwave
This also leads to shorter drying time. The microwave referred to in the present invention has a frequency of 100 MHz to 5000 MHz, preferably 800 MHz to 3000 MHz. The output of microwaves varies depending on the frequency used, the size of the irradiated object, the material, etc., but it ranges from 10W to
1kw, preferably 20w to 200w is more desirable.
When a bundle of wet hollow fibers containing water is irradiated with microwaves, the microwaves penetrate into the inside of the hollow fibers, where they are converted into heat, causing the moisture inside to become vaporized and dissipate to the outside, thus preventing drying. can.

This will be explained in more detail below with reference to Examples.

Embodiment FIG. 1 is a schematic diagram showing an embodiment of the apparatus according to the present invention and an example of the drying method of the present invention. The dryer 1 is a box made of metal such as aluminum or stainless steel.
A microwave generator 2 is connected to this. Microwaves oscillated by this generator pass through a waveguide 3 and enter the dryer 1. in this case,
In order to obtain uniform heating, a stirrer 4 was attached to the ceiling of the dryer 1. The hollow fiber used in the experiment was polysulfonate with a diameter of 200μ. After immersing 500 of these polysulfon hollow fibers in water or glycerin aqueous solution for 30 minutes, the length was 12 cm.
Cut into pieces, leaving 5 1.5 cm of the distal end to dry.
The other parts were covered with aluminum foil 6. Furthermore, a ground 7 was attached to the aluminum foil to avoid abnormal concentration of microwaves and to prevent the hollow fibers from melting. This hollow fiber was placed on a Teflon plate 8 placed in a dryer 1, and irradiated with microwaves at a frequency of 2450 MHz and an output of 100 W for 10 to 20 minutes. The dry condition was good. This polysulfon hollow fiber with only the ends dried was made into a module by sealing the ends with urethane resin, and the ultrafiltration capacity (UFRP) of the membrane was measured. 1000-1300ml/ for both those used after drying.
The expected performance was achieved with a value of hrmmHgm ² .

Comparative example: 12 bundles of 500 polysulfon membranes each with a diameter of 200μ
Cut into cm pieces and add 30 cm each to water or glycerin aqueous solution.
After soaking for 1 minute, the ends (both ends) were left 1.5 cm apart and the other parts were covered with aluminum foil. Hang this polysulfon membrane on a stand, and
A dryer with an output of 500 W was used to blow hot air from below cm, and each side was dried for 30 minutes. This membrane was made into a module by sealing the end with urethane resin, and the ultrafiltration performance (UFRP) was measured. It was 500 to 600 ml/hrmmHg for both water and glycerin aqueous solution immersion and drying.
^m2 , which was half of that using a membrane dried by microwave irradiation, and a decrease in performance was observed.

Although the method for modularizing hollow fiber medical blood separation membranes has been mainly described above, the separation membranes used in the present invention also include industrial membranes.
Furthermore, the method of the present invention can be similarly applied to not only hollow fiber type membranes but also flat membrane membranes.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an embodiment of a hollow fiber membrane drying method according to the method of the present invention. In the figure, 1 is a dryer, 2 is a microwave generator, 3 is a waveguide, 4 is a stirrer, 5 is the end of a polysulfon membrane, 6 is an aluminum foil, 7 is a ground,
8 indicates a Teflon plate.

Claims (1)

[Claims] 1 The end of the wet separation membrane is sealed with resin, and when making it into a module, a frequency is applied to the part of the membrane to be sealed.
A method for modularizing a separation membrane, characterized by drying it by irradiating it with microwaves of 100MHz to 5000MHz.