JPH01228504A - Porous hollow yarn membrane and production thereof and artificial lung - Google Patents

Abstract

PURPOSE:To eliminate the possibility of leak of blood plasma even when utilizing the title membrane for a long period by forming the holes communicating with the porous layer of the outer face of the membrane from the minute layer of the inner face consisting of polyolefin fine particles and regulating mean crimping amplitude, the ratio of maximum crimping amplitude to crimping semicycle at a time of maximum crimping amplitude and percentage crimp to the specified value. CONSTITUTION:The admixture consisting of PP, an organic filler such as liquid paraffin and a crystalline nucleus forming agent such as 1.3,2.4-bis(ethylbenzene) sorbitol is discharged hollow through an annular spinning hole and brought into contact with cooling and solidifying liquid to cool and solidify it and thereafter brought into contact with extract to extract and remove the organic filler. Then this hollow yarn membrane is wound into cross winding on a bobbin with a winder and heat-treated in an oven and crimped. In such a way, the porous polyolefin hollow yarn membrane in which mean crimping amplitude is regulated to 35-120% of the outer diameter of the membrane and the ratio (A/B) of maximum crimping amplitude to crimping semicycle at a time of maximum crimping amplitude is regulated to 0.01-0.1 and percentage crimp is 1.0-3.0% and gas exchange capacity is made large is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a porous hollow fiber membrane, a method for producing the same, and an oxygenator. Specifically, the present invention relates to a porous hollow fiber membrane that has high gas exchange ability and provides a large effective membrane area during gas exchange, a method for producing the same, and an oxygenator using the porous hollow fiber membrane.

(Conventional technology) In recent years, in heart surgery, etc., the patient's blood is guided outside the body.
In order to add oxygen and remove carbon dioxide gas, a hollow fiber membrane oxygenator is used in the extracorporeal circulation circuit.

There are two types of hollow fiber membranes used in such oxygenators: homogeneous membranes and porous membranes. In the uniform MM, the gas molecules that permeate are dissolved in the membrane and diffused, thereby causing gas movement. A typical example of this is silicone rubber, which has been commercialized as Mera Silox (Senko Medical Industries). However, from the point of view of gas permeability, only silicone rubber is known as the only membrane that can be used at present, and the thickness of the silicone rubber membrane cannot be reduced to less than 100 μm due to its strength. There is a limit to gas permeation through this slick, and the permeation of carbon dioxide gas is particularly poor. Furthermore, the silicone rubber has the drawbacks of being expensive and having poor processability.

On the other hand, in a porous membrane, the fine pores of the membrane are significantly larger than the gas molecules to be passed through, so that the gas passes through the pores as a volumetric flow. For example, various artificial lungs using porous membranes such as microporous polypropylene membranes have been proposed.

For example, polypropylene is processed using a hollow fiber manufacturing nozzle.
Spinning temperature 210-270°C, draft ratio 180-60
After melt spinning at 0°C, first stage heat treatment at 155°C or lower, stretching by 30 to 200% at lower than 110°C, and then second stage heat treatment at a temperature higher than the second stage heat treatment temperature and 155°C or lower. It has been proposed to produce porous polypropylene hollow fibers by
No. 123). However, in the porous hollow fiber membrane obtained in this way, the pores are physically formed by stretching the polypropylene hollow fibers, so the pores are also non-uniform, and the pores are distributed in the direction of the membrane thickness. Since the pores are linear side holes that are substantially horizontal to each other, and the pores are generated by cracking in the axial direction of the hollow fibers depending on the degree of stretching, the cross section is approximately slit-shaped. The small pores penetrate continuously in an almost straight line and have a high porosity. For this reason, the porous hollow fiber membrane has a high permeability to water vapor, and not only does its performance deteriorate due to condensation water, but also has the drawback that plasma leaks when blood is circulated for a long period of time.

From this point of view, as a method for imparting porosity without drawing, for example, polyolefin, an organic filler that can be uniformly dispersed in the polyolefin when the polyolefin is melted, and that is easily soluble in the extract liquid used. agent and a crystal nucleating agent, the kneaded product thus obtained is discharged in a molten state from an annular spinning hole, the hollow material is brought into contact with a cooling solidification liquid that does not dissolve the polyolefin, and is cooled and solidified; It has been proposed to produce a porous hollow fiber membrane by then bringing the cooled and solidified hollow material into contact with an extract that does not dissolve the polyolefin to extract and remove the organic filler (Japanese Patent Laid-Open No. 61-90705). issue). The porous hollow fiber membrane obtained in this way has smaller pores and more complex pore paths than the porous hollow fiber membrane obtained by the above-mentioned stretching method, so gas movement is not affected. However, it was sufficiently effective in suppressing permeation of plasma and water vapor, and the problem of plasma leakage as described above did not occur. However, even in an oxygenator using a porous hollow fiber membrane obtained in this way, when blood is circulated outside the hollow fiber membrane and oxygen-containing gas is blown inside the hollow fiber membrane, the hollow fiber membrane is Since the hollow fibers are hydrophobic, if the gap between the hollow fibers is narrow and has a substantially constant width from front to back, air or oxygen-containing gas tends to accumulate in this gap. When air or oxygen-containing gas accumulates in the gap between the hollow fiber and the hollow system, creating a so-called air-trapped state, blood circulation becomes impaired, and the trapped air or oxygen-containing gas clumps Since the contact of blood with oxygen-containing gas through the hollow fiber membrane is inhibited and the effective membrane surface area is reduced, a problem arises in that the gas exchange capacity of the oxygenator is reduced.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide an improved porous hollow fiber membrane, a method for manufacturing the same, and an artificial lung.

Another object of the present invention is to provide a porous hollow fiber membrane that has a high gas exchange ability, is free from the risk of plasma leakage during long-term use, and provides a high effective membrane area for gas exchange, a method for producing the same, and an oxygenator. shall be. A further object of the present invention is to provide a porous hollow fiber membrane, a method for producing the same, and an oxygenator in which there is little risk of deterioration in gas exchange performance due to air traps.

(Means for solving the problem) The above-mentioned various types have an inner diameter of 150 to 300 μm and a wall thickness of 10 μm.
A porous polyolefin hollow fiber membrane of approximately circular shape with a diameter of ~150 μm, the inner surface of the hollow fiber membrane exhibits a dense layer in which fine polyolefin particles are tightly bonded, and the outer surface thereof has fine polyolefin particles bonded in a chain shape. It exhibits a porous layer with fine communication holes formed from the inner surface side to the outer surface side, and has an average crimp amplitude of 35 to 120% of the outer diameter and 0.
A porous hollow fiber having a crimp half cycle ratio of maximum crimp amplitude/setting crimp amplitude of 0.01 to 0.1, and a crimp rate of 1.0 to 3.0%. Achieved by membrane.

The present invention also provides a porous hollow fiber membrane having a porosity of 5 to 60% and a gas flux of 100 to 1500 u/min.m2.atm.

The present invention further provides a porous hollow fiber membrane in which the polyolefin is polypropylene. The present invention also provides an average crimp amplitude of 50-100% of the outer diameter and 0.02-0.
．． This shows a porous hollow fiber membrane having a crimp half cycle ratio of maximum crimp amplitude/maximum crimp amplitude of 05 and a crimp rate of 2.0 to 3.0%.

The above methods also include kneading a polyolefin, an organic filler that is uniformly dispersed in the polyolefin while melting the polyolefin and being easily soluble in the extract used, and a crystal nucleating agent, and melting the kneaded product. The hollow material is discharged from an annular spinning hole in this state, and the discharged hollow material is cooled and solidified by contacting with a cooling solidification liquid that does not dissolve the polyolefin, and then the cooled and solidified hollow material is brought into contact with an extraction liquid that does not dissolve the polyolefin. The organic filler is extracted and removed using the method, and the hollow fiber membrane thus obtained is heated and crimped to give an outer diameter of 35 to
A crimp ratio of 1.0 to 3.0% with an average crimp amplitude of 120% and a maximum crimp amplitude / crimp half cycle ratio at maximum crimp amplitude of 0°01 to 0.1. This is achieved by a method for producing porous hollow fiber membranes.

The present invention is also achieved by a method for producing a porous hollow fiber membrane in which crimping is performed by cross-winding the obtained hollow fiber membrane around a bobbin and heat-setting it. The present invention further provides heat setting of 2 to 48℃ at 50 to 100℃.
This figure shows a method for producing a porous hollow fiber membrane, which is carried out for hours. The present invention also provides a method for producing a porous hollow fiber membrane in which the polyolefin is polypropylene. The present invention further provides a method for producing a porous hollow fiber membrane in which the organic filler is a hydrocarbon whose boiling point is higher than the melting point of the H polyolefin. The present invention furthermore provides
This shows a method for producing a porous hollow fiber membrane in which the hydrocarbons are liquid paraffin and primarily α-olefin oligomers. The present invention also provides a method for producing a porous hollow fiber membrane in which the amount of organic filler is 35 to 170 parts by weight based on 100 parts by weight of polyolefin. The present invention also provides a method for producing a porous hollow fiber membrane in which the crystal nucleating agent is an organic heat-resistant material having a melting point of 150° C. or higher and a gelation point higher than the crystallization initiation temperature of the polyolefin used. The present invention provides a method for producing a porous hollow fiber membrane in which the amount of crystal nucleating agent blended is 0.1 to 5 parts by weight per 100 parts by weight of polyolefin.

The above-mentioned aspects further provide that in an oxygenator comprising a hollow fiber membrane as a gas exchange membrane, the gas exchange membrane has an inner diameter of 150 mm.
It is a porous polyolefin hollow fiber membrane of approximately circular shape with a thickness of ~300 μm and a wall thickness of 10 to 150 μm, the inner surface of which exhibits an SR dense layer in which polyolefin fine particles are tightly bonded, and the outer surface of the membrane formed of polyolefin particles. It exhibits a porous layer in which fine particles are connected in a chain shape, and 1R-shaped communicating pores are formed from the inner surface to the outer surface, and is 35 to 120% of the outer diameter.
and a maximum crimp amplitude/maximum crimp amplitude time crimp half period ratio of 0.01 to 0.1, M! The shrinkage rate is 1.
This is achieved by an artificial lung characterized by using 0 to 3.0%.

The present invention also provides an artificial lung in which blood is circulated outside the hollow fiber membrane and oxygen-containing gas is insufflated inside the hollow fiber membrane. The present invention also provides an artificial lung in which blood is circulated inside the hollow fiber membrane and oxygen-containing gas is blown outside the hollow fiber membrane. The present invention further provides a porosity of 5 to 60% and a gas flux of 100 to 15004.
)/min-m2 ·atm.

The invention further provides an artificial lung in which the polyolefin is polypropylene. The present invention also provides that the hollow fiber membrane has an average crimp amplitude of 50-100% of the outer diameter and a crimp amplitude of 0.02-0.
．． This figure shows an oxygenator having a crimp half cycle ratio of maximum crimp amplitude/maximum crimp IFi width of 0.05 and a crimp rate of 2.0 to 3.0%.

(Function) Therefore, the method for producing a porous hollow fiber membrane of the present invention includes a polyolefin, an organic filler that is uniformly dispersed in the polyolefin while the polyolefin is melted and is easily soluble in the extract liquid used, and Kneading the crystal nucleating agent, discharging the kneaded material in a molten state from an annular spinning hole, discharging h7',
- the hollow body is cooled and solidified by contacting with a cooling solidification liquid that does not dissolve the polyolefin, and then the cooled and assimilated hollow body is brought into contact with an extraction liquid that does not dissolve the polyolefin to extract and remove the organic filler; The hollow fiber membrane obtained by
It is characterized by having a crimp ratio of 1.0 to 3.0% with an amplitude and a maximum crimp vibration@/maximum crimp amplitude half crimp period ratio of 0.01 to 0.1. be. The porous polyolefin hollow fiber membrane obtained by cooling and solidifying the organic filler blended into the molten dope of the raw material as described above and then extracting it with an extract liquid is also disclosed in JP-A-61-90705. As shown, the inner surface has a dense layer in which fine particles of polyolefin are closely bonded, and the outer surface has a porous layer in which fine particles of polyolefin are bonded in a chain form, and the IR conductor is formed from the inner surface to the outer surface. Because the pores are small and the pore paths are complex, it has high gas permeability and does not cause the problem of plasma leakage. When the porous hollow fiber membrane is crimped at a predetermined ratio as described above, an oxygenator is created using the porous hollow fiber membrane, and blood is circulated outside the hollow fiber membrane in this oxygenator. On the other hand, when oxygen-containing gas is blown into the inside of the hollow fiber membrane, although the hollow fiber membrane is hydrophobic, the gap between the hollow fibers is relatively large due to the crimping as described above, and the gap between the hollow fibers is within a certain limit from front to back. As changes occur within the gap, air or oxygen-containing gas hardly accumulates in this gap, and good blood circulation is achieved and blood and oxygen-containing gas are separated. Since uniform contact is made over the entire surface of the hollow fiber membrane, even better gas exchange performance can be obtained.

Hereinafter, the present invention will be explained in more detail based on embodiments.

FIG. 1 is a schematic diagram showing the manufacturing steps in one embodiment of the method for manufacturing a porous hollow fiber membrane of the present invention. That is,
As shown in FIG. 1, in this embodiment, a polyolefin, an organic filler, and a crystal nucleating agent are blended! I! 311
is supplied from the hopper 12 to a kneading machine, for example, a single-screw extruder 13, where the mixture 'tb tl is melt-kneaded and extruded.
(not shown) into a gaseous atmosphere, for example, air, and the hollow material 16 that comes out is cooled into a cooling tank 18 containing a solidified liquid 17. The liquid is introduced and brought into contact with the cooling solidification liquid 17 to be cooled and solidified. In this case, the hollow object 16
As shown in FIG. 1, the contact between the cooled solidified liquid 17 and the cooled solidified liquid 17 is carried out, for example, by flowing the cooled solidified liquid 17 into a cooled solidified liquid distribution pipe 19 that is provided downwardly through the bottom of the cooling tank 18. It is preferable to bring the hollow member 16 into cocurrent contact with the flow. The cooled solidified liquid 17 that has flowed down is received and stored in a solidification tank 20, into which the hollow object 16 is introduced, and the direction is changed by the direction change lI21 to bring it into sufficient contact with the cooled solidified liquid 17 and solidify it. M piles of cooled solidified liquid 16 are discharged from a circulation line 23 and circulated to the cooling tank 18 by a circulation pump 24. Next, the solidified hollow material 16 is guided by a drive roll 22a to a shower conveyor extractor 27 that showers down an extract 25 that dissolves the organic filler but does not dissolve the polypropylene. In this extractor 27, the hollow material 16 is brought into sufficient contact with the extracting liquid 25 while being conveyed on the belt conveyor 26, and the remaining organic filler is extracted by the BJ.
1 is removed, resulting in a hollow fiber membrane 16 with no porosity. The hollow fiber membrane 16° led out from the extractor 27 by the drive roll 22b undergoes further steps (not shown) such as re-extraction and drying as necessary, and then is led to the winding device 28 by the drive roll 22c. The winding device 28 winds the winding material around the bobbin 29 in a cross-winding manner. Further, the hollow fiber membrane 16' wound crosswise around the bobbin 29 is heat treated under appropriate conditions to fix the crimped state.

Polyolefins used as raw materials in the present invention include propylene homopolymers, ethylene homopolymers, and block polymers containing propylene as a main component with other monomers, and the melt index (M, 1.) is 5. ~70 is preferable, especially M,
1. is preferably 10 to 40. Further, among the polyolefins, propylene homopolymer is particularly preferable,
Among these, those with high crystallinity are most preferred.

The organic filler must be able to be uniformly dispersed in the polyolefin while it is melted, and be easily soluble in the extract as described below. Examples of such organic fillers include liquid paraffin (number average molecular weight 100 to 2,000), α-olefin oligomers [e.g. ethylene oligomer (number average molecular weight 100 to 2.000), propylene oligomer (number average molecular weight 100 to 2.000), 2,000>, ethylene-propylene oligomer (number average molecular weight 100-2.000), etc.], paraffin wax (number average molecular weight 200-2.5
00), various hydrocarbons, etc., preferably liquid paraffin.

The blending ratio of polypropylene and the organic filler is 35 to 1 part by weight of the organic filler per 100 parts by weight of polypropylene.
The amount is 70 parts by weight, preferably 80 to 150 parts by weight. That is, if the organic filler is less than 35 parts by weight, a porous hollow fiber membrane having sufficient gas permeability cannot be obtained;
This is because if it exceeds 0 parts by weight, the viscosity becomes too low and the moldability into hollow shapes deteriorates. Such raw material formulations are prepared (designed) by a pre-kneading method in which a mixture of a predetermined composition is melted and mixed using an extruder such as a twin-screw extruder, extruded, and then pelletized. .

In the present invention, the crystal nucleating agent blended into the raw material has a melting point of 150°C or higher (preferably 200°C to 25°C).
0°C) and has a gel point higher than the crystallization start temperature of the polyolefin used. The reason for blending such a crystal nucleating agent is to reduce the size of polyolefin particles, thereby narrowing the voids between the particles, that is, communicating pores, and increasing the pore density. - For example, 1,3,2,4-dibenzylidene sorbitol, 1,3,2,4-bis(O-methylbenzylidene)
Sorbitol, 1,3,2,4 bis(p-ethylbenzylidene) sorbitol, sodium bis(4-1-butylphenyl)phosphate, sodium benzoin, adipic acid, talc, kaolin, etc. are listed as crystal nucleating agents. .

As a crystal nucleating agent, benzylidene sorbitol, especially 1,3,2,4-bis(p-ethylbenzylidene) sorbitol, and 1,3,2,4-bis(p-methylbenzylidene) sorbitol are known to elute into the blood. Less is preferable.

The blending ratio of polypropylene and the crystal nucleating agent is 0.00 parts by weight of the crystal nucleating agent per 100 parts by weight of polypropylene.
The amount is 1 to 5 parts by weight, preferably 0.2 to 1.0 parts by weight.

The raw material mixture prepared in this way is further melted and kneaded using an extruder such as a single screw extruder at a temperature of, for example, 160 to 250°C, preferably 180 to 220°C, and quantitative analysis is performed if necessary. A high gear pump is used to discharge the spinning device into a gas atmosphere from an annular hole to form a hollow material. Note that gases such as nitrogen, carbon dioxide, helium, argon, and air may be self-suctioned into the center of the annular hole, or these gases may be forcibly introduced if necessary. Subsequently, the hollow material discharged from the annular hole is dropped and then brought into contact with the cooled solidified liquid in the cooling tank. The falling distance of the hollow object is preferably 5 to 1000 mm, especially 1
0 to 500 mm is preferred.

That is, if the falling distance is less than 5 mm, pulsation may occur and the hollow object may become immersed when it enters the cooling solidification liquid. The hollow object has not yet solidified sufficiently in this cooling tank, and since the central part is gaseous, it is easily deformed by external force, so as shown in Fig. 1,
For example, the cooled solidified liquid 17 is caused to flow down into a cooled solidified liquid distribution pipe 19 that is provided downwardly through the bottom of the cooling tank 18, and the hollow object 16 is brought into cocurrent contact with the flow. This makes it possible to forcibly move the hollow object 6 and prevent deformation of the hollow object due to external force (fluid pressure, etc.). At this time, the flow rate of the cooled and solidified liquid is sufficient under natural flow. Further, the cooling temperature at this time is 10 to 90°C, preferably 20 to 75°C. In other words, if the temperature is less than 10°C, the cooling solidification rate is too fast, and most of the thick part becomes a dense layer, resulting in a low gas exchange ability.On the other hand, if the temperature exceeds 90°C, the crystallization rate of the polyolefin decreases. Not only does the diameter of the fine particles on the outer surface become too large and the small communicating pores become too large, but the dense layer becomes extremely thin, or even disappears at higher temperatures, which makes it difficult to use, for example, in an oxygenator. If used, it may become clogged,
Otherwise, there is a possibility that plasma leakage may occur.

As the cooling solidification liquid, any mineral that does not dissolve the polyolefin and has a relatively high boiling point can be used. - Examples include alcohols such as methanol, ethanol, propatools, butanols, hexanols, octatools, and lauryl alcohol; liquid fatty acids such as oleic acid, palmitic acid, myristic acid, and stearic acid; Alkyl esters (e.g. esters M of methyl, ethyl, isoproyl, butyl, etc.)
, octane, nonane, decane, kerosene, diesel oil, toluene,
Liquid hydrocarbons such as xylene and methylnaphthalene,
Examples include halogenated hydrocarbons such as 1.2-trichloro-1,2゜2-trifluoroethane, trichlorofluoromethane, dichlorofluoromethane, and 1.1.2.2=tetrachloro-1,2-difluoroethane. However, it is of course not limited to these.

The hollow material cooled and solidified in the cooling solidification tank is sent to an extractor or the like via a diversion rod, where the organic filler is dissolved and extracted. The method for dissolving and extracting the organic filler is not limited to the shower method in which the extract is showered onto a hollow object on a belt conveyor as shown in FIG. Any method may be used as long as the hollow object can come into contact with the extract, such as a method of immersing the skein in the extract when the hollow object is rolled back into another skein. It is also possible to combine two or more methods.9 Any extract can be used as long as it does not dissolve the polypropylene constituting the hollow fiber membrane and can dissolve and extract the organic filler. - Examples include alcohols such as methanol, ethanol, propanols, butanol, pentanol, hexanol, octatool, lauryl alcohol, 1.1.2-trichloro-1,2,2-trifluoro Ethane, trichlorofluoromethane, dichlorofluoromethane, 1,1,2.
There are halogenated hydrocarbons such as 2-tetrachloro-1,2-difluoroethane, etc. Among these, halogenated hydrocarbons are preferable from the viewpoint of extraction ability for organic fillers, and chlorinated hydrocarbons are particularly preferred from the viewpoint of safety to the human body. Fluorinated hydrocarbons are preferred.

The porous hollow fiber membrane thus obtained is subjected to a heating crimping treatment. The method of heat crimping treatment is limited to the method of cross winding around a bobbin etc. and heat setting as shown in Fig. 1, as long as it can give a predetermined degree of crimp as described above. There are other methods, such as applying heat to a porous hollow fiber membrane and passing it between a pair of grooved rollers meshing like a Vg wheel, and applying heat to a porous hollow fiber membrane. A method may be used, such as adding the material, bending it in a zigzag shape and pushing it into a narrow funnel-shaped hole, and pushing it out from the smaller hole.

In the method for producing a porous hollow fiber membrane of the present invention, since the porous hollow fiber membrane is made of a thermoplastic resin, crimp at a predetermined ratio can be achieved by heating the porous hollow fiber membrane once. It is applied by cooling and fixing the crimp state. However, if the heat treatment for applying crimps is more than necessary, it will change the FA'li structure, for example, the porosity should not be reduced by 50% or more compared to the state before crimping. Even if the heat treatment is insufficient and the desired crimp state is maintained at the time of module assembly, the hollow fiber membranes are subsequently tensed due to residual stress and the crimp is lost. No effect will be obtained. For this reason, for example, in the method of cross-winding a bobbin or the like as shown in FIG.
It is desirable that the reaction be carried out at 80°C for 2 to 48 hours, more preferably 6 to 36 hours.

The porous hollow fiber membrane thus obtained has an inner diameter of 15
It is a substantially circular porous polyolefin hollow fiber membrane having a wall thickness of 0 to 300 μm, preferably 180 to 250 μm, and preferably 20 to 100 μm. In addition, the cross-sectional structure of the hollow fiber membrane varies slightly depending on the manufacturing conditions of the hollow fiber membrane, but generally the inner surface shows a dense layer in which fine polyolefin particles are tightly bonded, and the outer surface has fine polyolefin particles. It exhibits a porous layer connected in a chain shape, and fine communicating pores are formed from the inner surface to the outer surface. However, the porous hollow fiber membrane of the present invention can be made with an outer diameter of 35 to 120 by applying heat crimping treatment after imparting porosity by the extraction method as described above.
%, preferably an average crimp amplitude of 50-100% and 0
．． 01 to 0.1, preferably 0.02 to 0.05, with a maximum crimp amplitude/maximum crimp amplitude crimp half period ratio, and a crimp rate of 1.0 to 3.0%, preferably The crimp is 2.0-3.0%. In the porous hollow fiber membrane of the present invention, the average crimp amplitude is set to 35 to 120% of the outer diameter because:
If the average crimp amplitude is 35% of the outer diameter without grooves, the gap between the hollow fibers cannot be made sufficiently large when the porous hollow fiber membrane is incorporated into an oxygenator. There is a risk that air or oxygen-containing gas may easily accumulate in the gaps;
If the average crimp amplitude exceeds 120% of the outer diameter, it is difficult to maintain the size of the gap between the hollow fibers within a predetermined range when the porous hollow fiber membrane is incorporated into an oxygenator. This is because both are undesirable because they become difficult. Also, the maximum crimp amplitude/maximum crimp amplitude crimp half cycle ratio is 0°01~
The range of 0.1 means that the crimp half period ratio at maximum crimp amplitude/maximum crimp m amplitude is less than 0.01. When incorporated into the lung, the gap between the hollow fibers cannot be made sufficiently large, and air or oxygen-containing gas may easily accumulate in the gap. If the crimp half-period ratio at crimp amplitude exceeds 0°1, the size of the gap between the hollow fibers will fluctuate more than necessary when the porous hollow fiber membrane is assembled into an oxygenator. This is because the gap becomes large and the pressure loss in blood flow that uses the gap as a flow path becomes high, which is undesirable. Further increase the crimp rate to 1
．． The crimp ratio is 1.0% to 3.0%.
If it is less than 0%, when the porous hollow fiber membrane is incorporated into an oxygenator, the effect of increasing the gap between the hollow fibers by crimp will not be sufficient, and on the other hand, the crimp rate will be 3.0%
This is because if the size exceeds 100%, the module may become unnecessarily large when an oxygenator is created using the porous hollow fiber membrane, which is not preferable.

Furthermore, in the porous hollow fiber membrane of the present invention, the porosity is 5 to 5.
60%, more preferably 30 to 50%, and the gas flux is 100 to 15004)/min -m2 ・atm
, more storage area or 600-10001/rnjn-m2
・ATM is a desired characteristic for use in an artificial lung.

The hollow fiber membrane oxygenator of the present invention has an inner diameter of 15
It is a porous snow polyolefin hollow fiber membrane of approximately circular shape with a thickness of 0 to 300 μm and a wall thickness of 10 to 150 μm, the inner surface of which exhibits a dense layer in which fine polyolefin particles are tightly bonded, and the outer surface of which has fine polyolefin particles. It exhibits a chain-like porous snow layer with fine communicating pores formed from the inner surface to the outer surface, and has an average crimp amplitude of 35 to 120% of the outer diameter and 0.01 to 0.1. Maximum crimp vibration@/maximum crimp m amplitude has a crimp half-period ratio, and crimp rate is 1.0 to 3
．． 0% porous hollow fiber membrane as a gas exchange membrane, and its porous structure exhibits high gas exchange ability without causing problems such as plasma leakage. As mentioned above, since the gap between the hollow fiber and the hollow system is relatively large due to crimping and does not change within a predetermined limit from front to back, blood is circulated outside the hollow fiber membrane. On the other hand, even when oxygen-containing gas is blown inside the hollow fiber membrane, air or oxygen-containing gas hardly accumulates in this gap, and good blood circulation is achieved and the blood and oxygen-containing gas are separated. Since uniform contact is made over the entire surface of the hollow fiber membrane, higher gas exchange performance can be obtained.

Hereinafter, the structure of the hollow fiber membrane oxygenator of the present invention will be explained in more detail based on the drawings.

FIG. 2 shows an embodiment of the hollow fiber M-type oxygenator of the present invention, in which blood is circulated through one of the hollow fiber membranes and oxygen-containing gas is blown outside the hollow fiber membrane (the first embodiment). This figure shows the assembled state of the embodiment). That is, the hollow fiber membrane type oxygenator 5
1 includes a housing 52, which is provided with annular male threaded mounting covers 54 and 55 at both ends of a cylindrical body 53, and inside the housing 52,
A large number spread throughout, for example 10,000 to 60,000
Porous hollow fibers [16'' crimped at a predetermined ratio as described above are arranged in parallel and spaced apart from each other along the longitudinal direction of the housing 52. Both ends of the thread membrane 16' are connected to the partition wall 57 within the mounting cover 54, 55 with their respective openings not closed.
．． 58 in a liquid-tight manner. The above-mentioned layers 57 and 58 constitute a gas chamber 59 together with the outer circumferential surface of the porous hollow fiber membrane 16'' and the inner surface of the housing 52, close this, and fill the inside of the porous hollow fiber M16''. It isolates the gas chamber 59 from the blood circulation space (not shown) to be formed.An oxygen-containing gas inlet 60 for supplying oxygen-containing gas is provided in one mounting cover 54, and the other mounting cover The cover 55 is provided with an oxygen-containing gas outlet 61 for discharging oxygen-containing gas.

The inner surface of the cylindrical main body 53 of the housing 52 may be provided with a restricting portion 62 for restricting the diaphragm and protruding from the center in the axial direction. By providing the constriction restricting portion 62 in the center in this way, it is hoped that the gas exchange efficiency will be improved. Because of this, high gas exchange efficiency can be obtained without providing such a restricting portion 62. This restraint part 62 is the cylindrical main body 5
A large number of porous hollow fibers ym16° are formed integrally with the cylindrical body 53 on the inner surface of 3 and are inserted into the cylindrical body 53.
The outer periphery of the hollow fiber bundle 63 consisting of the following is tightened. In this way, the hollow fiber bundle 63 is constricted at the center in the axial direction, forming a constricted portion 64. Therefore,
The filling rate of the hollow fiber membrane differs in each part along the axial direction,
It is highest in the central part. In addition, the desirable filling rate in each part is as follows. First, as shown in FIG.
~80%, and the filling rate B in the other cylindrical body 53 is approximately 3
0 to 60%, and both ends of the hollow system bundle 63, that is, the partition wall 5
The filling factor C on the outer surface of 7.58 is about 20-40%.

Next, the formation of the partition walls 57 and 58 will be described. As mentioned above, the partition walls 57 and 58 perform the important function of isolating the inside and outside of the porous hollow fiber membrane 16''. Usually, the partition walls 57 and 58 are made of a highly polar polymer potting material. , such as polyurethane, silicone,
It is made by pouring epoxy resin or the like onto the inner wall surfaces of both ends of the housing 52 using a centrifugal injection method and hardening it.

More specifically, first, a large number of porous hollow fibers M16'' longer than the length of the housing 52 are prepared, and after sealing both open ends with a resin with high viscosity, the inside of the cylindrical body 53 of the housing 52 is Place them side by side. After this,
To install the cover, completely cover both ends of the porous hollow fiber membrane 16 with a mold cover that is larger than the diameter of the cover 54, 55, and rotate the housing 52 around the central axis of the housing 52 to cover both ends. The polymer potting material is poured in from the side. Once the resin has hardened after pouring, the mold cover is removed and the outer side of the resin is cut with a sharp knife to expose both open ends of the porous hollow fiber membrane 16". to be exposed to. Thus, partition walls 57 and 58 are formed.

The outer surfaces of the partition walls 57 and 58 are respectively covered with channel forming members 65 and 66 having annular projections. The flow path forming members 65 and 66 each include a liquid distribution member 67 and 68 and six screw rings and 70.1. Second liquid distribution member 6
The end surfaces of protrusions 71 and 72 as annular convex portions provided near the peripheral edges of 7.68 are brought into contact with the partition walls 57 and 58, respectively, and six screw rings and 70 are attached to the covers 54 and 55.
Blood inflow chambers 73 and 74 are respectively formed by screwing and fixing the two sides. A blood inlet 075 and a lower blood outlet are formed in the flow path forming members 65 and 66, respectively.

At least two holes 77,78 communicating with the gap are formed in the gap at the peripheral edge of the partition 57,58 formed by the partition 57,58 and the flow path forming member 65,66.
and 79.80 are sealed so as to be in contact with the partition wall 57.58. Alternatively, it can be sealed via an O-ring (not shown).

Next, FIG. 4 shows another embodiment of an oxygenator using the hollow fiber membrane of the present invention, in which blood is circulated outside the hollow fiber membrane and oxygen-containing gas is blown into the inside of the hollow fiber membrane (second embodiment). The assembled state of the embodiment) is shown. That is, the hollow fiber membrane oxygenator 81 is
The housing 82 is provided with annular covers 84 and 85 attached to both ends of the cylindrical body 83.
In the housing 82, a large number of porous hollow fiber membranes 16', for example 10,000 to 60,000, crimped at a predetermined ratio as described above are disposed throughout the housing 82 in the longitudinal direction of the housing 82. are arranged in parallel and spaced apart from each other along the . And this porous hollow fiber membrane 16″
The ends of each are supported in a liquid-tight manner by layers M87.88 in mounting covers 84.85 with their respective openings not closed. In addition, each of the above partition walls 87.8
8 indicates the outer peripheral surface of the porous hollow fiber membrane 16 and the housing 8.
Constructs a blood chamber 89 together with the inner surface of 2, occluding this chamber,
It also isolates the blood chamber 89 from the oxygen-containing gas circulation space (not shown) formed inside the porous hollow fiber M16''. One side of the housing 82 has a blood inlet 95 for supplying blood. A blood outlet 96 for discharging blood is provided on the other side of the housing.

On the inner surface of the cylindrical main body 83 of the housing 82, an aperture restricting portion 92 may be provided that protrudes from the center in the axial direction. That is, the restraint part 92 is formed integrally with the cylindrical body 83 on the inner surface of the cylindrical body 83, and
The outer periphery of a hollow fiber bundle 93 consisting of a large number of porous hollow fibers JI116- inserted therein is tightened.

In this way, the hollow fiber bundle 93 is narrowed at the center in the axial direction, forming a narrowed portion 94. Therefore, the filling rate of the hollow fiber membrane differs in each part along the axial direction, and is highest in the central part. Also, the installation is done with cover 8.
4.85 are formed with an oxygen-containing gas inlet 90 and an oxygen-containing gas outlet 91, respectively. Other parts, forming methods, etc. are similar to the hollow fiber membrane oxygenator according to the first embodiment described above, and therefore their explanations will be omitted.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

Implementation PjIJ1 130 parts by weight of liquid paraffin (number average molecular weight 324) and 1・3.2・4-bis( Ethylbenzene) 0.5 weight 1 part of sorbitol was charged, and a two-wheeled extruder (Ikegai Iron Works)
The mixture was melt-kneaded using a PCM-30-25 manufactured by PCM-30-25, a manufacturer of PCM-30-25 manufactured by PCM Corporation, and then extruded and pelletized. The pellets are processed using a device such as the one shown in Fig.
0) 13 at 180° C. and 3.6 to 5.0 g/mm from an annular spinning hole with a core diameter of 4 mm, an inner diameter of 6 mm, an outer diameter of 7 mm, and a land length of 15 mm.

It was discharged into the air at a discharge amount of , and the hollow object 16 was allowed to fall. Note that the falling distance was 20 to 30 mm. Subsequently, the hollow object 16 is cooled and solidified liquid 17 in a cooling tank 18 with Freon 113 (1,1,2-trichloro-1,2,2
- trifluoroethylene), and then brought into cocurrent contact with the cooled solidified liquid 17 flowing down naturally in the cooled solidified liquid flow pipe 19 for cooling. Note that the temperature of the cooled solidified liquid 17 at this time was 20°C. Next, the hollow object 16 is introduced into the cooled solidified liquid 17 in the solidification tank 20, and then changed direction by the change-of-direction rod 21, guided to the drive roll 22a at a speed of 80 m/min, and continuously conveyed using a shower conveyor system. In the extractor 27, the liquid paraffin is completely extracted with an extraction liquid 25 made of Freon 113. The hollow fiber membrane 16'' imparted with porosity in this manner is taken out from the extractor 27 by the drive roll 22b, and sent to the winding machine 28 via the drive roll 22C.
One winding was wound crosswise onto two bobbins each having a diameter of 95 mm. The hollow fiber membrane 16' thus wound up on the bobbin 29 in a crosswise manner is heat treated in an oven at 60'C for 18 hours to avoid crimping.

The average crimp amplitude of the porous hollow fiber membrane thus obtained was 72% of the outer diameter of the hollow fiber membrane, the crimp half period ratio at maximum crimp m amplitude/maximum crimp amplitude was 0.03, and the crimp half period ratio at maximum crimp amplitude was 0.03. The shrinkage rate was 1.7%. Using this crimped porous hollow fiber membrane, the artificial lung according to the first aspect described above is produced as described below.
In the oxygenator according to the second aspect and the oxygenator according to the first aspect, an oxygenator module of a type (third aspect) in which the hollow fiber bundle is not constricted at the center in the axial direction is created, and oxygen gas flux, oxygen gas Additive and carbon dioxide scavenging capacities and plasma leakage were measured. The results are shown in Table 3.

Comparative Example 1 For comparison, a porous hollow fiber membrane was prepared in the same manner as in Example 1 except that the crimping treatment was not performed, and the obtained porous hollow fiber membrane was used in the same manner as in Example 1. A module of an artificial lung according to the first aspect and an artificial lung according to the second aspect were created, and oxygen gas flux, oxygen gas addition ability, carbon dioxide gas removal ability, and plasma leakage were measured. 3rd result
Shown in the table.

Comparative Example 2 A micropore with an average pore radius of 700 formed by stretching in the axial direction by a stretching method, an inner diameter of 2°0 μm, and a wall thickness of 2
A 4 μm polypropylene porous hollow fiber membrane with a diameter of 95
The material was wound in a cross-wrap onto a 2.0 mm bobbin, and crimped by heat treatment in an oven at 60° C. for 18 hours. The average crimp amplitude of the porous hollow fiber membrane thus obtained was 70% of the outer diameter of the hollow fiber membrane, the crimp half period ratio at maximum crimp M amplitude/maximum crimp amplitude was 0.03, and the crimp half period ratio at maximum crimp amplitude was 0.03. The shrinkage rate was 2.5%. Regarding the porous hollow fiber membrane thus obtained, the oxygenator according to the above-mentioned first aspect, as in Example PA1,
Modules of an oxygenator according to the second embodiment and an oxygenator according to the third embodiment were created, and oxygen gas flux, oxygen gas addition capacity, carbon dioxide removal capacity, and plasma leakage were measured.

The results are shown in Table 3.

Ten of the obtained hollow fiber membranes are randomly extracted and cut into rounds with a length of about 0.5 mm using a sharp razor. The cross section was projected onto a universal projector using a ConProfile Projector-V-12, and a ConDigital Counter C was used as a measuring instrument.
M-63) was measured for its outer diameter d1 and inner diameter d2, and the wall thickness t was calculated by t=di-d2, and the average value of the 10 pieces was taken.

Take about 2g of the hollow fiber membrane obtained by porosity%, and use a sharp razor to cut it into 5m.
Cut into rounds less than m long. The obtained sample was heated to 1000k using a mercury porosimeter (Carlo Erba Model 65A).
Pressure is applied to g/cm2, and the porosity is obtained from the total pore amount (pore size of the hollow fiber membrane per unit weight).

Hollow fiber membrane can be measured using a universal surface shape measuring device (■ Koita Research Institute -3E)
When the crimp state was evaluated by measuring the surface unevenness over a length of 35 mm at -3A>, the amplitude (A
> divided by the distance PI (B) from the maximum point to the minimum point when obtaining the amplitude, the ratio (A/B) is 1 for every 10 points.
The measurement was performed 0 times, and the average value was defined as the maximum crimp amplitude/the crimp half cycle ratio at the maximum crimp amplitude. Moreover, the average value of the amplitude of the part with the largest amplitude during one measurement of 10 times was taken as the average crimp amplitude.

A tensile test was conducted on the hollow fiber membrane with an initial length of 25 mm using a tensile testing machine (manufactured by Toyo Seiki ■; Strograph T), and the elongation was measured when the load was 1 mg per denier and when the load was 50 mg. The difference divided by the initial length was expressed as a percentage.

Taxisen Um2 Yuenodama porous hollow fiber membrane, effective length 14cm, effective membrane area 0.02
After creating a 5m2 mini module and closing one end, apply a pressure of 1 atm inside the hollow fiber membrane with oxygen, and measure the flow rate of oxygen gas when it reaches a steady state using a flowmeter (Kusaburi Kagaku Kiki Seisakusho). , float meter).

Addition of elementary gas] utA″-°”; acid gas removed by 1 (first, 9th type) An oxygenator module with an effective length of 130 mm and a wA membrane area of 4 m2 was created using a hollow fiber membrane, and a cow was added inside the hollow fiber membrane. Single pass (SinOle Path) of standard venous blood
) and 6. Pure oxygen was flowed at a flow rate of 6.0 Ω/min to the outside of the hollow fiber membrane, and the pH 1 carbon dioxide partial pressure (PC
O2), oxygen gas partial pressure (PO2) with blood gas measuring device 71
(manufactured by Radiometer, BGA type 3), and the partial pressure difference between the oxygenator inlet and the oxygenator outlet was calculated.

The details of the oxygenator module specifications are shown in Table 1. The properties of standard arterial blood are shown in Table 2.

(Second Embodiment) An oxygenator module with an effective length of 90 mm and a membrane area of 2°1 m2 was created using a hollow fiber membrane, and bovine blood (standard venous blood) was passed through the outside of the hollow fiber membrane in a single pass (Sin(llePath >
And 6. By flowing pure oxygen at a flow rate of Ou/min inside the hollow fiber membrane at a flow rate of 6.0Ω/min, the pH 1 partial pressure of carbon dioxide (PCO2) of bovine sap at the inlet and outlet of the oxygenator was
, measure oxygen gas partial pressure (PO2) with blood gas measuring device 7fl (
The partial pressure difference between the oxygenator inlet and the oxygenator outlet is calculated. The details of the oxygenator module model are shown in Table 1.

(Third Embodiment) An oxygenator according to the first embodiment in which the hollow fiber bundle is not constricted at the center in the axial direction was created, and the oxygen gas addition ability and carbon dioxide removal ability were similarly measured.

We created an artificial lung module similar to the one used for the oxygen gas addition and carbon dioxide removal functions, and performed jugular and carotid artery cannulation using a mongrel dog (body weight approximately 20 kg).
The artificial lung module (membrane area: 1.6 m2) was installed in a partial VA bypass circuit (Membrane area: 1.6 m2) by Ion), and extracorporeal circulation was performed for 30 hours, and the amount of plasma leaking from the inside of the hollow system was measured. Furthermore, even if no leakage was confirmed, a trace amount of plasma leakage was also confirmed by examining the protein reaction of droplets with water vapor outside the hollow system.

1°1 Membrane area (rrl') 5.4 2.1
5.0 Number (pieces) 62000 328
00 57400 Effective length/Total length (cm) 14/
17 9/13.5 14/17 Filled Hayabusa (%) Δ section 66 56 54B section
54 42 54C section 53
30 50Table 1 5.4 2.1 5.4 2.1 5.014/17
9/13.5 14/17 9/13.5 1.4/1
7 Blood Hematocrit Hemoglobin Concentration Excess Base Oxygen Saturation Partial Pressure of Carbon Dioxide Temperature Table 2 Fresh heparinized blood 35% (adjusted with physiological saline) 12±1 g/cN O±2 mEq /J) (adjusted with bicarbonate of soda) 65± 5% 45±5m0 37±2℃ Porosity (%) 37 Oxygen gas flux 480(,f!/m
in −m 2 ・atm ) (rrJ /m i
n > Carbon dioxide removal capacity 250 260 296
(ml!/min> Plasma leakage after 30 hours -- did not occur Table 3 260 1B0 262 272 273 After 30 hours
-17 hours later--Company d Kai (Effects of the invention) As described above, the present invention has an inner diameter of 150 to 300 μm.
, almost circular polyrL3ff with a wall thickness of 10 to 150 μm
A polyolefin hollow fiber membrane, the inner surface of the hollow fiber membrane exhibits a dense Jm in which polyolefin fine particles are closely bonded, and the outer surface exhibits a porous JΔ in which polyolefin fine particles are bonded in a chain form, and the inner surface Fine communication holes are formed from the side to the outer surface, and the diameter is 35 to 120% of the outer diameter.
It has an average crimp 5 width of
3.0%, for example, an oxygenator is created using the porous hollow fiber membrane, and blood is circulated outside the hollow fiber membrane in this oxygenator. On the other hand, when oxygen-containing gas is blown into the inside of the hollow fiber membrane, the gap between the hollow fibers is relatively large due to the crimping as described above, and changes within a predetermined limit from front to back. Because of this, air or oxygen-containing gas hardly accumulates in this gap, resulting in good blood circulation and uniform contact between blood and oxygen-containing gas over the entire surface of the hollow fiber membrane. In order for this to be done,
A high gas exchange ability can be obtained, and problems such as plasma leakage do not occur due to the M structure. Furthermore, in the porous hollow fiber membrane of the present invention, the porosity is 5 to 60%.
So, the gas flux is 100 to 1500 Jll/mi
nm2・atm, and the polyolefin is polypropylene, and in addition, the average crimp width is 50 to 100% of the outer diameter, and the maximum crimp amplitude is 0.02 to 0.05. It has a crimp half-period ratio, and the crimp rate is 2.0 to 3.
．． If it is 0%, the above-mentioned effects will be even more excellent, making it more suitable as a hollow fiber membrane for an oxygenator.

The present invention also involves kneading a polyolefin, an organic filler that is uniformly dispersed in the polyolefin when the polyolefin is melted and is easily soluble in the extract used, and a crystal nucleating agent to form a blended product. The molten state is discharged from an annular spinning hole, the discharged hollow material is cooled and solidified by contacting the hollow material with a cooling solidification liquid that does not dissolve the polyolefin, and then the cooled and solidified hollow material is made into an extraction liquid that does not dissolve the polyolefin. The organic filler is extracted and removed by contact, and the thus obtained HF and hollow fiber membranes are heated and crimped to form an outer diameter of 35~
Crimp $ with an average crimp amplitude of 120% and a maximum crimp amplitude / crimp half period ratio at maximum crimp amplitude of o, oi ~ 0.1
Since this is a method for producing a porous hollow fiber membrane characterized in that the content of the porous hollow fiber membrane is 1.0 to 3.0%, the It is possible to produce a porous hollow fiber membrane having the above-mentioned excellent properties with improved gas-liquid contact efficiency in gas exchange without impairing exchange efficiency or the like. Furthermore, in the method for producing a porous hollow fiber membrane of the present invention, crimping is achieved by winding the obtained hollow fiber membrane crosswise around a bobbin and heat-setting it. If the process is carried out at 50 to 100°C for 2 to 48 hours, it is easier to obtain a porous membrane with a shape that has high gas-liquid contact efficiency and a stable structure that is extremely excellent in other properties. The polyolefin is polypropylene, the organic filler is a hydrocarbon having a boiling point higher than the melting point of the polyolefin, the hydrocarbon is liquid paraffin or an α-olefin oligomer, and the organic filler is based on 100 parts by weight of the polyolefin. The blending amount is 35 to 170 parts by weight, the crystal nucleating agent is a heat-resistant material with a melting point of 150°C or higher and a gelling point higher than the crystallization start temperature of the polyolefin used, and 100 parts by weight of the polyolefin. If the amount of the crystal nucleating agent is 0.1 to 5 parts by weight, the performance of the porous hollow fiber membrane obtained will be even better.

Furthermore, the present invention provides an oxygenator comprising a hollow fiber membrane as a gas exchange membrane, wherein the gas exchange membrane has an inner diameter of 150 to
It is a porous polyolefin hollow fiber membrane of approximately circular shape with a diameter of 300 μm and a wall thickness of 10 to 150 μm, the inner surface of which exhibits a dense layer in which fine polyolefin particles are tightly bonded, and the outer surface of which has fine polyolefin particles arranged in a chain shape. RHJ communicating holes are formed from the inner surface side to the outer surface side by exhibiting a combined porous snow layer, and an average crimp amplitude of 35 to 120% of the outer diameter and a maximum crimp of 0.01 to 0.1. It has a crimp half-period ratio of amplitude/maximum crimp amplitude, and a crimp rate of 1.0 to 3.0.
Since this is a hollow fiber membrane type oxygenator that uses a material that is When oxygen-containing gas is blown into the hollow fiber, there is no risk that the oxygen-containing gas or air will accumulate in the gap between the hollow fiber and the hollow system, and gas exchange can be carried out efficiently. Furthermore, even when blood is circulated inside the hollow fiber membrane and oxygen-containing gas is blown to the outside of the hollow fiber membrane, gas exchange can be performed efficiently. Even without narrowing down in the center,
Similar gas exchange efficiencies can be obtained. In other words, in the type in which blood flows inside the hollow fiber membrane, water vapor contained in the oxygen-containing gas inside the oxygenator condenses on the inner surface of the oxygenator housing during gas exchange, causing the hollow fiber surface to become wet with water droplets. may come into close contact with the inner surface of the housing. For this reason, a predetermined layer is placed between the hollow fiber bundle and the inner surface of the housing to prevent the hollow fiber bundle from coming into close contact with the inner surface of the housing. If this happens, the gas will flow only in that part, so a constriction part is provided only in the center to prevent channeling from occurring. However, when the crimped hollow fiber membrane of the present invention is used, condensation does not form on the inner surface of the housing because the hollow fiber membrane itself is crimped, even without increasing the layer between it and the inner surface of the housing. Even if this occurs, the hollow fiber membrane and the inner surface of the housing will not come into close contact.
In particular, it is so smooth that the gas exchange efficiency does not deteriorate even if no constriction part is provided. Furthermore, in the oxygenator of the present invention, the porosity of the hollow fiber membrane is 5 to 60%, and the gas flux is 10%.
0~1500. /min-m2-atm, the polyolefin is polypropylene, and the hollow fiber membrane has an average crimp amplitude of 50 to 100% of the outer diameter and 0.0
Having a maximum crimp amplitude/maximum crimp amplitude time crimp half period ratio of 2 to 0,05 and a crimp rate of 2°O to 3,0%, a more compact artificial body with even ehfs performance It is what becomes the lungs.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an apparatus that can be used in the method for producing a porous hollow fiber membrane according to the present invention, and FIG. 2 is a half sectional view showing a hollow fiber M type oxygenator 311 according to the present invention.
FIG. 3 is a sectional view showing each part related to the hollow fiber membrane filling rate in the same embodiment, and FIG. 4 is a half-plane view showing the embodiment of the hollow fiber membrane type oxygenator according to the present invention. Figure 5 shows the maximum crimping amplitude/maximum crimping amplitude/crimping half-period ratio (A/B
) is a drawing showing measurement positions. 11... Raw material mixture, 12... Hopper, 13...
・Single screw extruder, 14... Spinning device, 15... Annular spinning hole, 16... Hollow object, 16''... Hollow fiber membrane, 1
7... Cooling solidified liquid, 18... Cooling tank, 19... Cooling solidified liquid distribution pipe, 20... Solidifying tank, 21... Changing direction, 22a, 22b, 22 c-... Drive roll, 2
3...Circulation line, 24...Circulation pump, 25...
・Extract liquid, 26... Belt conveyor, 27... Shower conveyor type extractor, 28... Winder, 2
9... Bobbin, 51.81... Hollow fiber membrane oxygenator, 52.82... Housing, 53.83... Cylindrical body, 57.58.87.88... Partition wall, 5 89...Gas chamber, 60.90...Oxygen-containing gas inlet, 61.91...
- Oxygen-containing gas outlet, 63.93...Hollow fiber bundle, 75.95...Blood inlet, 76.96...Blood outlet, 89...Blood chamber.

Claims (6)

[Claims] (1) Inner diameter is 150-300μm, wall thickness is 10-150μm
It is a porous polyolefin hollow fiber membrane having an approximately circular shape of μm in diameter, and the inner surface of the hollow fiber membrane exhibits a dense layer in which fine polyolefin particles are tightly bonded, and the outer surface thereof has fine polyolefin particles bonded in a chain shape. It exhibits a porous layer with fine communicating pores formed from the inner surface to the outer surface, and has an average crimp amplitude of 35 to 120% of the outer diameter and 0.01 to 0.01.
A porous hollow fiber membrane having a crimp half cycle ratio of maximum crimp amplitude/maximum crimp amplitude of 0.1 and a crimp rate of 1.0 to 3.0%. (2) Average crimp amplitude of 50-100% of the outer diameter and 0.
The porous hollow fiber membrane according to claim 1, having a maximum crimp amplitude/maximum crimp amplitude crimp half period ratio of 02 to 0.05, and a crimp rate of 2.0 to 3.0%. . (3) Knead a polyolefin, an organic filler that is uniformly dispersed in the polyolefin when the polyolefin is melted and is easily soluble in the extract used, and a crystal nucleating agent, and the kneaded product is fused into a cyclic form. The hollow material is discharged from a spinning hole, and the discharged hollow material is cooled and solidified by contacting with a cooling solidification liquid that does not dissolve the polyolefin, and then the cooled and solidified hollow material is brought into contact with an extractant that does not dissolve the polyolefin to form an organic filling. The agent is extracted and removed, and the thus obtained hollow fiber membrane is heated and crimped to give an average crimping amplitude of 35 to 120% of the outer diameter and a maximum crimping amplitude/maximum crimping of 0.01 to 0.1. A crimp rate with a crimp half-period ratio at the time of contraction amplitude of 1.0 to 3.
A method for producing a porous hollow fiber membrane, characterized in that the porous hollow fiber membrane is 0%. (4) The method for producing a porous hollow fiber membrane according to claim 3, wherein the crimping is carried out by winding the obtained hollow fiber membrane around a bobbin in a cross-winding manner and heat-setting it. (5) The method for producing a porous hollow fiber membrane according to claim 3 or 4, wherein the heat fixation is carried out at 50 to 100°C for 2 to 48 hours. (6) An oxygenator comprising a hollow fiber membrane as a gas exchange membrane, characterized in that the gas exchange membrane is formed using the porous hollow fiber membrane according to claim 1 or 2.