JPH0465505A - Production of conjugate hollow fiber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing composite hollow fibers made of organic polymer compounds. More specifically, it is a hollow fiber composed of different or the same kind of organic polymer compounds, in which two layers are joined, the inner diameter is 100 to 500μ, and the total layer thickness, which is the sum of the thicknesses of each layer, is 10 to 500μ. This invention relates to a method for spinning a 100μ composite hollow fiber.

[Prior art 1 In recent years, artificial kidneys, plasma purification membranes such as plasma separation, reverse osmosis-
In addition, for the purpose of creating a separation membrane with 14 permeability such as a gas separation membrane such as an oxygen enrichment membrane, a polymer having high selective separation permeability for a specific target substance is uniformly coated on the surface of a porous body. A composite separation membrane formed into a thin film and a method for manufacturing the same have been proposed.

However, with conventional methods, it is difficult to form a thin film, and the materials from which it can be made are also limited.

There is also a method of spinning two layers of hollow fiber using two concentric annular spinnerets, but stable spinning is difficult, for example, when the inner layer is made thinner than the outer layer.

[Problems to be Solved by the Invention] For example, when spinning a two-layer hollow fiber with a thinner inner layer, it may be difficult to stably supply a trace amount of the polymer solution to the inner layer. The present invention aims to provide a method for stably forming a film in such a case.

[Means for Solving the Problems] As a result of intensive research in order to solve the problems, the present inventors have found that the present inventors perform spinning using a two-layer hollow fiber spinning nozzle equipped with two concentric annular discharge ports. In this case, it was discovered that effective spinning can be achieved even if the discharge speed at the thinner layer discharge port is greater than the discharge speed at the thicker layer discharge port within a certain range, and the present invention was achieved based on this finding. It is.

That is, the present invention provides a hollow fiber in which two layers composed of different or the same kind of organic polymer compounds are joined, and the inner diameter is 100 to 50.
0μ, total layer thickness that is the sum of the two layer thicknesses is 10 to 10
0 μ, the thickness dl of one layer and the thickness d of the other layer
When manufacturing a composite hollow fiber in which the ratio d+ / d1/d2 of l is 2 or more, a hollow fiber manufacturing nozzle having two annular discharge ports arranged concentrically is used, and each discharge port has a different type of fiber. or a composite characterized in that organic polymer compounds of the same type are supplied separately, and the linear velocity of the organic polymer compound in the other layer at the nozzle discharge port is 5 times or less that of the one layer. A method for manufacturing hollow fibers is provided.

According to the present invention, the type of organic polymer in each layer of the multilayer composite hollow fiber, the micropore diameter of each layer, the charge of each layer, etc. can be appropriately selected, and the permeability of substances can be improved.

It has the characteristics of being able to greatly change the compatibility and compatibility with the liquid and gas that come into contact with the hollow fiber membrane.

The composite spinning used in the present invention is essentially melt spinning.

Both wet spinning and dry spinning are included, and excellent performance and quality can be obtained with either spinning method. A wide variety of organic polymer compounds are used, such as polyamide, polyester, cellulose ester, cellulose ether,
Polyacrylonitrile.

polyolefin, polyvinyl, polycarbonate.

Examples include polymethyl methacrylate and copolymers of their respective components. The combination of organic polymer compounds in each layer is
As long as composite spinning is possible, a combination of the same type or a different type may be used. It is preferable to use different types of organic polymer compounds, for example, an organic polymer compound for providing the inner thin layer with a substance separation function. It is also possible to blend two or more types of organic polymers or to mix an additive plasticizer. In order to impart a porous structure to each layer, for example, inorganic salts or low-molecular compounds that are inert to the polymer may be added, or when spinning a 5-molecular compound as a solution, a non-solvent for the polymer may be added. A porous structure can be developed by extracting after spinning from a material containing a foaming agent or a foaming agent containing a suitable foaming agent.

In the present invention, it is sufficient to use known methods to form tubular hollows in the fibers. That is, in melt spinning and dry spinning, a gas or liquid that is inert to the polymer is introduced from the outside through a nozzle hole to form a hollow part, and in wet spinning, a liquid that has coagulability is injected into the polymer. methods etc. are effective.

FIG. 1 shows one example of a specific shape of a spinneret for manufacturing the hollow fibers of the present invention. This shows a two-layer composite hollow fiber base, in which the organic polymer compound for forming the outer layer (A> is supplied to the flow path 1 and discharged from the discharge hole 3, and the organic polymer compound for forming the inner layer (B) is supplied to the flow path 2 and is discharged from the discharge hole 4. At the same time, a suitable gas or liquid is introduced into the IIN through the flow path 5 and from the discharge hole 6 to form a hollow fiber composite membrane. When the two layers of A and polymer B are bonded together, peeling may occur between the two layers, uneven thickness of each layer may occur, or breakage of the hollow fibers may occur during spinning. As a result of intensive study on this point, it was found that it is preferable not to make the difference in the ejection linear velocity of each polymer at the ejection ports of both layers too large. When the discharge linear velocity (Ul) when being discharged from the hole 3 is 5 times or less of the discharge linear velocity (Ul) when the organic polymer compound for forming the outer layer (A> is discharged from the discharge hole 4, The bonding state of 2W is good.The ratio U2/Ul of their ejection linear velocities is preferably 4 or less.If the ejection linear velocities of Polymer A and Polymer B differ more than this, the ejection holes Distortion occurs between the discharged polymer layers at the exit due to the difference in speed, resulting in yarn breakage due to more discharge of both polymers, uneven thickness of each layer in the discharge direction, or peeling at the interface between the two layers after solidification. may occur.It should be noted that such ratio U2/Ul
The lower limit of 1 is preferably 1 because stable spinning can be performed.

Further, in the manufacturing method of the present invention, the thickness d of the outer layer of the hollow fiber
The ratio d+/d2 between l and the inner layer thickness d2 is preferably 2 or more, more preferably 5 or more.

By making the inner layer thinner in this way, material permeability can be increased.

FIG. 2 is a sectional view showing another example of the spinneret according to the present invention. In this case, the discharge linear velocity of polymer A is the linear velocity of the portion 8 in FIG. The discharge linear velocity refers to the linear velocity at the portion 7 in the figure. In FIG. 2, 11 is the flow path for polymer A, and 1
2 is a flow path for polymer B, which indicates that gas or liquid passes through the flow path 9 and is introduced into the fiber from the discharge port 10.

The hollow fiber according to the present invention is intended to provide a separation membrane that is permeable to an island flow rate in an artificial kidney, a blood purification membrane such as plasma separation, a gas separation membrane such as a reverse osmosis membrane, and an oxygen enrichment membrane. The appropriate inner diameter of the hollow fiber is such that the flow resistance of the fluid passing through the hollow part is not too excessive, that is, an inner diameter of about 50 to 500μ, and the membrane thickness is the sum of the thickness of each layer. Although it is desirable that the layer thickness be thin, a thickness of 10 to 100 μm is appropriate from the viewpoint of spinning hollow fibers.

The present invention provides a method for manufacturing a hollow fiber system in which wJM is provided on either the inside or the outside. However, in the case of blood processing such as hemodialysis, hollow fibers with a thin layer on the inside are preferred. is suitable.

Examples are shown below.

The exception layer component polymer is triacetate mixed with 75% by weight of sulfolane and polyethylene glycol as a spinning plasticizer, and the inner layer component polymer is diacetate mixed with 30% polyethylene glycol as a spinning plasticizer.
% mixture was used for spinning using the spinneret shown in FIG. The two components of the inner and outer layers are each melted in separate extruders, and the inner and outer layer components are measured separately.
Discharge at the discharge port at the discharge linear velocity shown in the separate figure, approximately 30
It was rolled up at a speed of 0 m/min.

The obtained Ill is a concentric two-layer composite hollow SSI with an almost perfect circle cross section, and the outer diameter, inner diameter, and thickness of each single ** are 280 mm.
The membrane had an asymmetric structure with μ, 200μ, and 40μ. The thickness of the outer layer was about 36μ, and the thickness of the inner layer was about 4μ. The results of measuring the peeling and thickness unevenness of the inner layer in the cross section of these hollow fibers are shown in the attached table.

The film thickness unevenness is expressed as the maximum film thickness minus the minimum film thickness in a single fiber.

As described above, by increasing the linear velocity of the polymer in the inner layer at the nozzle outlet to 1 to 5 times the linear velocity of the outer layer, the two-layer composite material is free from peeling of the inner and outer layers of the composite hollow fiber and has less uneven thickness of the inner layer. Hollow fibers are obtained.

<Effects of the Invention> According to the present invention, composite hollow fibers having material separation properties selected from a wide range can be stably produced using a simple spinneret. In particular, the thin inner layer, which has a decisive influence on the material separation properties, can be formed stably, and the bonding state between the inner layer and the outer layer of the composite hollow fiber obtained can also be improved.

[Brief explanation of drawings]

1 and 2 are cross-sectional views schematically illustrating a preferable spinneret used in the method for producing composite hollow fibers of the present invention. Patent applicant Teijin Ltd.

Claims (1)

[Claims] A hollow fiber in which two layers composed of different or similar organic polymer compounds are joined, and the inner diameter is 100 to 500μ, and the total thickness of the two layers is 10 to 100μ,
The ratio d_ of the thickness d_1 of one layer to the thickness d_2 of the other layer
When manufacturing a composite hollow fiber in which 1/d_2 is 2 or more, a hollow fiber manufacturing nozzle having two annular discharge ports arranged concentrically is used to inject different or the same type of organic high-carbon into each discharge port. A method for producing a composite hollow fiber, characterized in that the molecular compounds are supplied separately, and the linear velocity of the organic polymer compound in the other layer at the nozzle discharge port is 5 times or less that of the one layer. .