JPH04212372A - Composite membrane for artificial lunge, production thereof and composite type artificial lunge formed by using this method - Google Patents

Abstract

PURPOSE:To provide the above artificial lunge which obviates the leakage of blood plasma during long-term use, maintains a sufficient gas exchange capacity and has an excellent antithrombotic property by forming a film consisting of a specific water-swellable polymer compd. on the inside surfaces of the pores of a specific porous membrane. CONSTITUTION:The porous membrane is a hollow yarn-like porous membrane having 5 to 80mum thickness, 20 to 80% porosity, 0.01 to 5mum pore size and 100 to 1000mum inside diameter and the water-swellable high-polymer compd. has 30 to 80wt.% moisture content and >=2 swelling ratio. The water-swellable polymer compd. is at least one kind of the water-swellable polymer compds. selected from a group consisting of a (meth)acrylic acid system, polyvinyl alcohol system, etc. The porous membrane is formed by coating the inside surfaces of the pores of the porous membrane with the water-swellable polymer compd. The composite membrane which does not allow the leakage of the blood plasma during the long-term use, has the sufficient gas exchange capacity and has the excellent antithrombotic property is obtd.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite membrane for an oxygenator, a method for producing the same, and a composite membrane oxygenator using the same. In detail, a composite membrane for oxygenator lungs that does not cause plasma leakage during long-term use, maintains sufficient gas exchange ability, and has excellent antithrombotic properties, its manufacturing method, and a composite membrane oxygenator using the same. It is related to.

0002

[Prior Art] Conventionally, a membrane oxygenator has been used as an auxiliary means for open heart surgery, etc., which performs gas exchange by bringing blood into contact with oxygen-containing gas through a gas exchange membrane having good gas permeability. ing. In addition to having good gas permeability, this gas exchange membrane also has high mechanical strength, no leakage of plasma even when blood circulates for a long period of time, and no damage to the blood even if it comes into contact with blood. That is, performance such as not causing blood coagulation, microthrombus formation, platelet loss, plasma protein denaturation, hemolysis, etc. is required. There are currently two types of gas exchange membranes used in membrane oxygenators: homogeneous membranes and porous membranes. As homogeneous membranes, silicone membranes are mainly used, while as porous membranes, polyethylene, Various materials are used, such as polypropylene, polytetrafluoroethylene, polysulfone, polyacrylonitrile, polyurethane, and polyamide.

0003

[Problems to be Solved by the Invention] However, the silicone homogeneous film does not have sufficient strength, and the film thickness has been reduced to 100 μm.
For this reason, there is a limit to gas permeation, especially for carbon dioxide, and in order to achieve the desired gas exchange performance, for example, when tens of thousands of hollow fiber membranes are bundled together, The size of the device increases, the amount of priming increases, and the cost is also high.

On the other hand, porous membranes have a large number of fine pores that communicate in the membrane thickness direction, but because the membrane is hydrophobic, plasma does not pass through the pores, that is, the membrane This makes it possible to add oxygen in the gas to the blood and remove carbon dioxide in the blood into the gas without causing plasma leakage from the blood flow path side to the other gas flow path side. However, since porous membranes have high water vapor permeability, not only do they degrade in performance due to condensation, but when blood is circulated for long periods of time, plasma may actually leak out. Such a phenomenon is also observed in artificial lungs that have been tested for water leakage during the manufacturing stage and found to be free of abnormalities, and is a phenomenon that occurs during use. Furthermore, the materials used for porous membranes are rarely considered to be sufficient in terms of biocompatibility such as platelet loss. In addition, coating the inner surface of a porous membrane with a functional polymer has been practiced in order to impart necessary physical properties, but since the supporting surface of the membrane is porous and hydrophobic, the coating is not uniform. However, when the functional polymer is coated, the pores of the porous membrane are also coated, making the membrane hydrophilic and causing plasma to easily leak out. Furthermore, when immobilizing heparin on the membrane surface, there is a problem in that the polymer coated in advance tends to peel off.

[0005] Accordingly, an object of the present invention is to provide a novel composite membrane for an oxygenator, a method for manufacturing the same, and a composite membrane type oxygenator using the same. Another object of the present invention is to provide a composite membrane for an oxygenator that does not cause plasma leakage during long-term use, maintains sufficient gas exchange ability, and has excellent antithrombotic properties, a method for producing the same, and a composite membrane using the same. The purpose is to provide a membrane oxygenator.

[0006]

[Means for Solving the Problems] These objects are achieved by a composite membrane for an artificial lung, which is formed by coating the inner surface of the pores of a porous membrane with a water-swellable polymer compound.

[0007] The present invention also provides that the porous membrane has a wall thickness of 5 to 80 mm.
The composite membrane for an artificial lung is a hollow fiber-like porous membrane having a porosity of 20 to 80%, a pore diameter of 0.01 to 5 μm, and an inner diameter of 100 to 1,000 μm. The present invention further provides a composite membrane for an artificial lung, in which the water-swellable polymer compound has a water content of 30 to 80% by weight and a swelling ratio of 2 or more. The present invention also provides that the water-swellable polymer compound is at least one type of water selected from the group consisting of (meth)acrylic acid type, polyvinyl alcohol type, (meth)acrylamide type, polyalkylene oxide type, and polyalkylene imine type. This is a composite membrane for artificial lungs that is a swellable compound. The present invention further provides a composite membrane for an artificial lung, which is a water-soluble polymer compound crosslinked with a water-swellable compound. The present invention also provides a composite membrane for an artificial lung, in which the water-soluble polymer compound is at least one selected from the group consisting of polyalkylene imine and (meth)acrylate. The present invention further provides a composite membrane for an artificial lung, which is coated with a water-swellable compound to a thickness of 0.01 to 5 μm.

[0008] These objects are to provide a composite membrane for an artificial lung, which is characterized in that a solution of a water-soluble polymer compound is applied to the surface of a porous membrane, and then the water-soluble polymer compound coating is cross-linked. This can also be achieved by the manufacturing method.

The present invention also provides a solution of a water-soluble polymer compound on the surface of the porous membrane at a rate of 0.2 to 2.0 kg/cm 2 .
The present invention shows a method for producing a composite membrane for an oxygenator, which is applied by contacting the membrane at a pressure of . The present invention further provides a method for producing a composite membrane for an artificial lung, in which the crosslinking treatment is carried out by bringing a crosslinking agent liquid into contact with the water-soluble polymer compound coating. The present invention also provides a method for producing a composite membrane for an artificial lung, in which the crosslinking treatment is performed by irradiating the water-soluble polymer compound coating with radiation.

[0010] These objects can also be achieved by a method for producing a composite membrane for an oxygenator, which is characterized in that a solution containing a water-soluble polymer compound and a crosslinking agent is applied to the surface of a porous membrane. Ru.

[0011] These objectives are achieved by using a composite membrane in which the inner surface of the pores of a porous membrane is coated with a water-swellable polymer compound as a gas exchange membrane, and providing oxygen inlet, oxygen outlet, blood inlet and This can also be achieved by a composite membrane oxygenator which is housed in a housing provided with a blood outflow port and forms a blood flow path and an oxygen flow path through the composite membrane.

The present invention also provides a composite membrane obtained by contacting at least the surface of the porous membrane that comes into contact with blood with a solution of a water-swellable polymer compound, removing the solvent, and then subjecting it to crosslinking treatment. It is a type of artificial lung.

[0013]

[Operation] The porous membrane used in the present invention is a porous membrane made of various resins, regardless of the shape of the hollow fiber membrane or flat membrane.
For example, an example of a hollow fiber membrane is a membrane made of polyolefin such as polypropylene or polyethylene, and its wall thickness is 5 to 80 μm, preferably 10 to 60 μm,
The porosity is 20-80%, preferably 30-60% and the average pore size is 0.01-5 μm, preferably 0.01
~1.0 μm, the inner diameter is 100 ~ 1,000 μm,
Preferably it is 100 to 300 μm.

[0014] Such a hydrophobic porous membrane can also be produced by a stretching method;
704, JP-A-61-90, 705, JP-A-61-
As disclosed in No. 90,707, JP-A No. 62-106,770, etc., a polyolefin, which is uniformly dispersed in the polyolefin when the polyolefin is melted, and is easily soluble in the extract liquid used. An organic filler and a crystal nucleating agent are kneaded, the kneaded product thus obtained is discharged from a nozzle in a molten state, the discharged molten film is brought into contact with a cooling fluid to be cooled and solidified, and then cooled and solidified. It is also possible to produce a flat membrane by bringing the polyolefin into contact with an extractant that does not melt the polyolefin and extracting and removing the organic filler.

The method for producing the composite membrane for an oxygenator according to the present invention and the resulting oxygenator will be explained below by taking a hollow fiber membrane as an example. That is, FIG. 1 shows an assembled state of a hollow fiber membrane oxygenator, which is an embodiment of the hollow fiber composite membrane oxygenator of the present invention. That is, the hollow fiber membrane oxygenator 1 includes a housing 6, which is provided with annular male-threaded mounting covers 8 and 9 at both ends of a cylindrical body 7, respectively.
Within, there are many, for example 10,000 to 10,000.
60,000 hollow fiber-like porous membranes (gas exchange membranes) 2 having pores as described above are arranged in parallel and spaced apart from each other along the longitudinal direction of the housing 6. and,
Both ends of the gas exchange membrane 2 are connected to the partition walls 10 and 1 with their respective openings not closed within the mounting covers 8 and 9.
1 in a liquid-tight manner. In addition, each of the compartments 10
, 11 constitute an oxygen chamber 12 which is a first mass transfer chamber together with the outer periphery of the gas exchange membrane 2 and the inner surface of the housing 6,
It closes this and isolates the oxygen chamber 12 from a blood circulation space (not shown), which is a second mass transfer fluid space formed inside the gas exchange membrane 2.

One of the mounting covers 8 is provided with an inlet 13 for supplying oxygen, which is the first mass transfer fluid. The other mounting cover 9 is provided with an outlet 14 for discharging oxygen.

It is preferable that the inner surface of the cylindrical main body 7 of the housing 6 is provided with a constriction restricting portion 15 that protrudes from the center in the axial direction. That is, the restraint part 15 is formed integrally with the inner surface of the cylindrical body 7, and tightens the outer periphery of the hollow fiber bundle 16, which is made up of a large number of gas exchange membranes 2 and is inserted into the cylindrical body 7. It looks like this. In this way, the hollow fiber bundle 16 is narrowed at the center in the axial direction to form a narrowed portion 17, as shown in FIG. Therefore, the filling rate of the gas exchange membrane 2 differs in each part along the axial direction, and is highest in the central part. Note that, for reasons to be described later, the desirable filling rate of each part is as follows. First, the filling rate in the central constricted portion 17 is about 60 to 80%, and the filling rate in the other cylindrical body 7 is about 30%.
~60%, and both ends of the hollow fiber bundle 16, that is, the partition wall 10
, 11 is about 20-40%.

Next, the formation of the partition walls 10 and 11 will be described. As described above, the partition walls 10 and 11 perform the important function of isolating the inside and outside of the gas exchange membrane 2. Normally, the partition walls 10 and 11 are made by pouring a highly polar polymer potting material such as polyurethane, silicone, epoxy resin, etc. onto the inner wall surfaces at both ends of the housing 6 using a centrifugal injection method and hardening the material. More specifically, first, a large number of hollow fiber membranes 2 longer than the length of the housing 6 are prepared, both open ends of which are sealed with a highly viscous resin, and then lined up inside the cylindrical body 7 of the housing 6. position. After this, install the gas exchange membrane 2 with a mold cover larger than the diameter of the mounting covers 8 and 9.
The polymer potting material is introduced from both end sides while rotating the housing 6 about its central axis. When the resin has hardened after pouring, the mold cover is removed and the outer surface of the resin is cut with a sharp knife to expose both open ends of the gas exchange membrane 2 to the surface. The partition walls 10 and 11 are thus formed.

The outer surfaces of the partition walls 10 and 11 are respectively covered with flow path forming members 18 and 19 having annular convex portions. The flow path forming members 18 and 19 are respectively connected to the liquid distribution member 2.
0, 21 and screw rings 22, 23, the end surfaces of protrusions 24, 25 as annular convex portions provided near the peripheral edges of the liquid distribution members 20, 21 are brought into contact with the partition walls 10, 11, respectively, and the screw rings By screwing and fixing 22 and 23 to the mounting covers 8 and 9, respectively, an inflow chamber 26 and an outflow chamber 27 for blood, which is the second mass transfer fluid, are respectively formed. A blood inlet 28 and an outlet 29, which are a second mass transfer fluid, are formed in the flow path forming members 18 and 19, respectively.

The partition walls 10 and 11 and the flow path forming member 18
, 19 at the peripheral edges of the partition walls 10, 11, there are at least two holes 32 communicating with the gaps.
, 33 is filled with fillers 34, 35, thereby sealing the partition walls 10, 11 so as to contact them. Alternatively, it is sealed via an O-ring (not shown).

The first mass transfer fluid inlet 13 or outlet 1 of the artificial lung module thus formed
4 or second mass transfer fluid inlet 28 or outlet 29
By flowing a solution of a water-soluble polymer compound, the pores of the porous membrane, which is a gas exchange membrane, are filled.

[0022] At this time, the contact pressure of the solution to the porous membrane is adjusted to 0.2 to 2 Kg/cm 2 by narrowing the outlet of the solution of the water-soluble polymer compound, etc. By passing a portion of the solvent through the pores and drawing it out, the concentration of the water-soluble polymer compound increases, allowing efficient filling and coating. Although it is possible to use a solution that has been adjusted to a high concentration in advance, the viscosity of the solution increases and it is difficult for the solution to flow into the pores. On the other hand, according to the method of adjusting the contact pressure, a solution with a relatively low concentration and low viscosity is used as the solution to flow into the pore, and the flow into the pore is smooth. Later, the concentration of the water-soluble polymer compound can be increased by adjusting the contact pressure to allow only the solvent to flow out. That is, according to such a method, there is no need to repeat the filling operation, and the coating can be efficiently performed with a minimum number of filling operations. Examples of the water-swellable polymer compound used in the present invention include crosslinked water-soluble polymer compounds. Such a polymer compound is usually used as a solution of a water-soluble polymer compound as described above, and then crosslinked to form a water-insoluble water-swellable coating. Crosslinking treatment is usually performed after coating with a water-soluble polymer compound solution. Such a crosslinking treatment is carried out, for example, by bringing the coating of the water-soluble polymer compound into contact with a liquid (for example, a solution) of a crosslinking agent that can cause a crosslinking reaction with the water-soluble polymer compound. In addition, gamma rays, β
Crosslinking treatment can also be performed by irradiating with radiation such as rays, particularly gamma rays.

Furthermore, after the solution containing the water-soluble polymer compound and the crosslinking agent is brought into contact with the porous membrane, excess solution may be discharged and crosslinking may be carried out by heating or other means.

Examples of water-soluble polymer compounds include (
Examples include meth)acrylic acid, polyvinyl alcohol, (meth)acrylamide, polyalkylene oxide, and polyalkylene imine. (Meth)acrylic acid-based polymer compounds include (meth)acrylic acid, methacrylic acid, its salts, methyl acrylate, ethyl acrylate, isopropyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, butyl methacrylate, etc. Examples include single or copolymers of acrylic esters and the like. As the polyvinyl alcohol-based polymer compound, for example, the degree of polymerization is 500 or more, preferably 1,700 to 3,000.
The degree of saponification is 80 mol% or more, preferably 95 mol% or more. As the (meth)acrylamide-based polymer compound, there is a (meth)acrylamide polymer having a weight average molecular weight of 100,000 to 1,000,000, preferably 200,000 to 300,000. Examples of polyalkylene oxide-based polymer compounds include polyethylene oxide and polypropylene oxide having a weight average molecular weight of 400 to 10,000, preferably 600 to 5,000. As a polyalkylene imine-based polymer compound, weight average molecular weight is 40,000 to 100,000,
Preferably, polyethyleneimine, polypropyleneimine, etc. having a weight of 60,000 to 70,000 are used. It is preferable that these polymeric compounds have a size that prevents them from being drawn out through the pores by the above-mentioned pressurization and coating operations.

Examples of crosslinking agents for the (meth)acrylic acid-based polymer compound include melamine-based compounds, guanamine-based compounds, isocyanate-based compounds, and polyamine-based compounds. Examples of crosslinking agents for polyvinyl alcohol-based polymer compounds include melamine-based compounds, isocyanate-based compounds, and polyamine-based compounds. As a crosslinking agent for (meth)acrylamide-based polymer compounds,
Examples include N,N'-methylenebisacrylamide. Examples of crosslinking agents for polyalkylene oxide-based polymer compounds include isocyanate-based compounds and polyamine-based compounds. Furthermore, examples of crosslinking agents for polyalkyleneimine polymer compounds include glutaraldehyde and formaldehyde.

The amount of these crosslinking agents is varied depending on the water content and swelling ratio required for the water-insoluble, water-swellable polymer compound coating formed on the inner surface of the pores of the porous membrane.

The film of the water-insoluble water-swellable polymer compound thus obtained has a water content of 30 to 80% by weight;
Preferably it is 40 to 60% by weight, and the swelling ratio is 2 or more. Furthermore, the film thickness of the film is 0.01 to 5 μm.
, preferably 0.01 to 0.5 μm.

[0028] The above explanation has been about the hollow fiber membrane type oxygenator, but flat membrane type oxygenators such as the laminated type, one membrane wound into a coil shape, and the one folded in a zigzag shape are also applicable. If the pores of the gas exchange membrane used are blocked by fine particles smaller than the pore system, and at least the blood contact surface is coated with a biocompatible hydrophobic resin, the contact is highly biocompatible. A membrane oxygenator can be obtained in which damage to blood platelets, etc. is extremely small, the gas exchange ability is excellent, and there is no risk of plasma leakage even when used for a long period of time.

[0029]

[Examples] The present invention will be explained in more detail below with reference to Examples.

Example 1 Using a polypropylene hollow fiber membrane with an inner diameter of 200 μm, a wall thickness of 25 μm, a porosity of 38%, and an average pore diameter of 700 angstroms, a hollow fiber membrane type artificial membrane as shown in FIG. 1 with a membrane area of 0.8 m2 was prepared. Assembled lung 1. Poly(2-hydroxyethyl methacrylate) was diluted with ethanol to a 1.25 w/v% solution, and polyethyleneimine (Polyethyleneimine) was diluted with ethanol.
In SN, manufactured by BASF Corporation) was added to the coating solution to give a coating solution of 1.0 w/v%. After filling the membrane oxygenator with the prepared coating solution, this solution is discharged to remove the solvent, and then dried. After repeating this immersion and drying operation 4 to 6 times, the concentration of 1 .0w/v
% of glutaraldehyde, the solution was removed, and the mixture was heated to 37° C. for 16 to 20 hours to effect crosslinking and drying.

Comparative Example 1 A hollow fiber membrane oxygenator as shown in FIG. 1 with a membrane area of 0.8 m2 was made using a polypropylene hollow fiber membrane with an inner diameter of 200 μm, a wall thickness of 25 μm, a porosity of 38%, and an average pore diameter of 700 angstroms. Assembled.

Example 2 The following experiment was conducted to examine the water content and swelling ratio of the oxygenators obtained in Example 1 and Comparative Example 1.

A flat membrane of a microporous polypropylene membrane (Duraguard, manufactured by Polyplastics Co., Ltd.) was used as a base material, and the same operations as in Example 1 and Comparative Example 1 (untreated) were carried out. The obtained flat membrane was heated to 37°C.
After being immersed in water at 37°C for 2 days, air-dried for 1 day and night, then truly dried at room temperature for 1 day and night, and again immersed in water at 37°C for 1 day and then measured, and the water content and swelling ratio were measured using the following formula. , the results shown in Table 1 were obtained.

[0034]

[Math 1]

[0035]

[Table 1]

When the air permeation flow rate of the membrane oxygenator obtained in Example 1 was measured, it was found to be 850 ml/min·m2.
・mmHg, and the air permeation flow rate of the membrane oxygenator obtained in Comparative Example 1 was 1,000 ml/min ・m2 ・
It was mmHg. On the other hand, the air permeation flow rate of the membrane oxygenator (referred to as Comparative Example 2) before filling was 1,100 ml/mi.
When compared with n ・m 2 ・mmHg, each decreased.

Furthermore, in order to evaluate the gas exchange capacity of these membrane oxygenators and to examine the amount of plasma leakage, in vitro (in vitro)
In vitro) and animal studies were conducted.

(1) In vitro test Using fresh heparinized bovine blood, oxygen gas partial pressure was 35 mmHg.
Venous blood having a partial pressure of carbon dioxide gas of 45 mmHg was prepared, and its performance was evaluated by passing it through the blood flow path of the artificial lung. The hemoglobin content of the cow blood used is 11.5g.
/dl and the temperature was 37°C. The relationship between oxygen gas addition ability and carbon dioxide removal ability when the ratio of oxygen flow rate to blood flow rate is 1 and the blood flow rate is 600 ml/min is shown in Table 2.
It was as shown in

[0039]

[Table 2]

(2) Animal Test A 24-hour VA partial extracorporeal circulation test was conducted on the membrane oxygenators of Example 1 and Comparative Example 1 using mongrel dogs. The relationship between circulation time and plasma leakage amount was as shown in Table 3.

[0041]

[Table 3]

(3) Gas flux test Using distilled water at a temperature of 37° C., the circuits of the artificial lungs of Example 1 and Comparative Example 1 were primed, and after circulation, air was blown at 200 liters/min for 30 seconds. Then, air drying (10 liters/min) was performed, and the relationship between drying time and glass flux was as shown in Table 4. From the above, it was inferred that the coated polymer compound clogged the pores during circulation.

[0043]

[Table 4]

Example 3 Using a polypropylene hollow fiber membrane with an inner diameter of 200 μm, a wall thickness of 25 μm, a porosity of 38%, and an average pore diameter of 700 angstroms, a hollow fiber membrane type artificial membrane as shown in FIG. 1 with a membrane area of 0.8 m2 was prepared. Assembled lung 1. Poly(2-hydroxyethyl methacrylate) from the blood inlet with ethanol for 1.2
It was diluted to a 5 w/v% solution, and 1.0 w/v of polyethyleneimine (Polymin SN, manufactured by BASF) was added thereto.
A coating solution was prepared by adding the solution in an amount of v%. The prepared coating liquid was flowed into the membrane oxygenator, the outlet was constricted, the internal pressure of the hollow fiber membrane was adjusted to about 1 Kg/cm 2 , and 1 liter of ethanol was discharged through the pores. Next, it was dried, filled with an aqueous solution of glutaraldehyde at a concentration of 1.0%, crosslinked at 37°C for 16 to 20 hours, and then the solution was removed and dried. When the water content and swelling ratio of the artificial lung thus prepared were examined, the results were almost the same as those of the artificial lung of Example 1. Furthermore, this oxygenator showed almost the same results as the oxygenator of Example 1 regarding the gas exchange ability and the amount of plasma leakage.

[0045]

Effects of the Invention As described above, the present invention provides a composite membrane for an oxygenator in which the inner surface of the pores of a porous membrane is coated with a water-swellable polymer compound, and a composite membrane using the composite membrane. Since it is a type of oxygenator, the water-swellable polymer compound comes into contact with blood during extracorporeal blood circulation, swells, and closes the pores, so blood does not come into contact with oxygen-containing gas through the swelling membrane. There is no leakage of plasma due to gas exchange. Furthermore, during priming, bubbles escape more easily than with a homogeneous membrane, and are equivalent to a hydrophobic porous membrane. This means that
This means that during priming, the advantages of a homogeneous membrane can be exhibited during circulation of a porous membrane.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view showing an embodiment of an artificial lung according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Membrane oxygenator, 2... Gas exchange membrane, 3... Pore, 4... Particulate, 5... Film,
6... Housing, 7... Cylindrical main body, 10, 11... Partition wall, 12... First mass transfer chamber, 13, 14... First mass transfer fluid introduction outlet, 1
6...Hollow fiber bundle, 28, 29...Second
mass transfer fluid inlet outlet.

Claims (14)

[Claims] 1. A composite membrane for an artificial lung, comprising a porous membrane whose pore inner surfaces are coated with a water-swellable polymer compound. 2. The porous membrane has a wall thickness of 5 to 80 μm, a porosity of 20 to 80%, a pore diameter of 0.01 to 5 μm, and an inner diameter of 10 μm.
The composite membrane for an artificial lung according to claim 1, which is a hollow fiber-like porous membrane having a diameter of 0 to 1,000 μm. Claim 3: The water-swellable polymer compound has a water content of 30 to 30.
The composite membrane for an artificial lung according to claim 1 or 2, having a swelling ratio of 80% by weight and a swelling ratio of 2 or more. 4. The water-swellable polymer compound is at least one type of water selected from the group consisting of (meth)acrylic acid type, polyvinyl alcohol type, (meth)acrylamide type, polyalkylene oxide type, and polyalkylene imine type. The composite membrane for an artificial lung according to claim 3, which is a swellable compound. 5. The composite membrane for an artificial lung according to claim 3, wherein the water-swellable compound is a crosslinked water-soluble polymer compound. 6. The composite membrane for an artificial lung according to claim 5, wherein the water-soluble polymer compound is at least one selected from the group consisting of polyalkyleneimine and (meth)acrylate. 7. The composite membrane for an artificial lung according to claim 1, wherein the composite membrane is coated with a water-swellable compound to a thickness of 0.01 to 5 μm. 8. A method for producing a composite membrane for an artificial lung, comprising applying a solution of a water-soluble polymer compound to the surface of a porous membrane, and then subjecting the water-soluble polymer compound coating to a crosslinking treatment. 9. A solution of a water-soluble polymer compound is applied to the surface of a porous membrane by contacting the solution at a pressure of 0.2 to 2.0 Kg/cm 2 and allowing the solvent to be drawn out through the pores. A method for producing a composite membrane for an oxygenator according to claim 8. 10. The method for producing a composite membrane for an artificial lung according to claim 8, wherein the crosslinking treatment is carried out by bringing a crosslinking agent liquid into contact with the water-soluble polymer compound coating. 11. The method for producing a composite membrane for an artificial lung according to claim 8, wherein the crosslinking treatment is carried out by irradiating the water-soluble polymer compound coating with radiation. 12. A method for producing a composite membrane for an artificial lung, comprising applying a solution containing a water-soluble polymer compound and a crosslinking agent to the surface of a porous membrane. 13. A composite membrane in which the inner surface of the pores of a porous membrane is coated with a water-swellable polymer compound is used as a gas exchange membrane, and an oxygen inlet, an oxygen outlet, a blood inlet, and a blood outlet are provided. A composite membrane oxygenator is housed in a housing provided with a composite membrane, and a blood flow path and an oxygen flow path are formed through the composite membrane. 14. The porous membrane according to claim 13, wherein at least the surface of the porous membrane that comes into contact with blood is brought into contact with a solution of a water-swellable polymer compound, the solvent is removed, and a crosslinking treatment is further performed. composite membrane oxygenator.