JPH0260780B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrafine porous continuous hollow fiber bundle and a method for producing the same.

The present invention utilizes extremely microporous continuous hollow fiber bundles based on an entirely new concept that has not been seen before, to be used as filters for various separation purposes, for retention, adsorption, and sorption of catalysts and enzymes, as well as for heat insulation, The purpose is to provide a new form suitable for moisture permeable applications. Yet another purpose is
It is an object of the present invention to provide a fine, particularly ultrafine, porous continuous hollow fiber bundle suitable for such uses, and a preferred form suitable therefor.

Still another object is to provide a method for easily producing such ultrafine porous continuous hollow fiber bundles.

Other purposes will be clarified later in the explanation, but the basics are separation of specific components from blood etc., bacteria separation, virus separation, smoke separation, catalysts for industrial chemical reactions, etc. The aim is to contribute to humanity through the development and application of basic materials and their forms used in medicine and industry, such as the preservation of enzymes.

As far as we have investigated the conventional methods aimed at this field, we believe that the following methods have been used or have been used.

For example, hollow fibers in artificial kidneys. However, this is a method that uses uneven fine voids in the fiber wall, rather than the fine hollows that are the object of the present invention, and the hollow pores themselves are quite large. The hollow hole itself is not used for the purpose of separation, and the direction of separation is perpendicular to the hollow hole.

Moreover, the manufacturing method itself belongs to spinning technology for large hollow fibers, and does not relate to uniform fine hollow fibers. Furthermore, since separation is performed from the fiber wall, it is necessary to maintain a certain distance between the fibers and to increase the exchange area.

In addition, the general method of spinning hollow fibers is to make use of the fusion of polymers immediately after spinning to create a hollow fiber while entrapping air, or to spin the fibers together with air (air as one component). The method was spinning.

With such methods, the fibers themselves become very thick, it is extremely difficult to control the hollow portions into fine pores, and the fibers tend to be thick and thin and uneven.
It has the disadvantage that it is extremely difficult to obtain a material that is extremely fine and has pores, has a high porosity, or has pores that are uniformly arranged.

These methods have in common that there is no use of micropores that are continuous in the fiber axis direction for separation, and no efforts have been made for this purpose.

As a result of intensive studies to achieve the intended purpose of the present invention, the following invention has finally been achieved. The main points are (1) A large number of fibers are bundled, each having a maximum pore diameter of ultra-fine 7 to 0.01 microns, and each fiber having many independent continuous micropores that are parallel to the fiber axis and have substantially the same pore diameter. 1. An ultra-fine porous sheet-like plate, which is formed by being aligned and fixed with a fixing agent and integrated, and having a cut surface with planar holes at both ends of the holes.

(2) After arranging a large number of sea-island fibers made of at least two components and having a large number of islands with a diameter of 7 to 0.01 microns, and fixing and integrating them with an adhesive, the top and bottom are cut into planar shapes, and then the islands are A method for producing an ultra-fine porous sheet-like plate, characterized by removing components.

(3) The island component is spinnable and exhibits fluidity rather than solidity at least at room temperature, and the sea component is made of a plastic material that retains its solidity at lower temperatures. Claim 2, characterized in that the removal is carried out in a certain state at least by extrusion or centrifugal force.
A method for producing an ultrafine porous sheet-like plate as described in Section 1.

This will be explained in more detail using figures.

FIG. 1 is a model diagram in which the island component is removed from a highly preferred embodiment of the polymer mutually arrayed fiber, ie, the so-called "sea-island type composite fiber." The number, size, and arrangement of island components can be arbitrarily varied. However, for purposes of the present invention, large numbers of well-matched pore sizes are particularly preferred. Here, the island component is "substantially" in the fiber axis direction.
Must be continuous. It will be understood that for use in filtration, etc., the efficiency is better as the column is made from a column with a larger number of holes per cross-sectional area, that is, a column with a higher proportion of island components.

Since a single fiber alone cannot provide a sufficient area for the separation operation, it is preferable to devise a fiber bundle bound with an adhesive or filler, and provide openings at both ends.

The island component may be removed from the bundled material to make it microporous, or it may be made into microporous material and then bundled. When we talk about bundling here, it actually has a sheet-like or board-like spread, so it is often so thin that at first glance you might think it is a bundle. This is preferable because it is easier to remove the island components later. The most preferable method for aligning the surfaces is to cut or slice after tying.

When removing the island components later (removal by treatment such as decomposition/dissolution, extraction, extrusion, centrifugal force, etc.), it is preferable that the binding material is not removed.

When the interfiber space is smaller than the diameter of the pore, there are few problems as a whole, but on the other hand, when it is large, the space should be filled with a filler (including adhesive) to block it. Things are good.

Developing this idea, even if such fibers are peeled or split type composite fibers commonly known as polymer blend fibers, petal-shaped fibers, chrysanthemum-petal-shaped fibers, and rice-shaped fibers, if they are used in a bundle, they can be Although the objective can be achieved to a certain degree, in order to obtain continuous ultra-fine pores having a similar cross-sectional area, it is most preferable to use polymeric mutually arrayed fibers. Polymer blend fibers and peelable fibers contain components exposed on the surface (equivalent to islands), which act as micropores in relation to the binding material and adjacent fibers, but they also have irregular points. The sea-island type fiber shown in FIG. 1 is most preferable.

Figure 2 shows fibers arranged in a bundle and tied together, which corresponds to the hollow fibers 2 having micropores 1 in Figure 1, and a large number of fibers 4 having micropores 3 are bundled and fixed. It is integrated and has planar cut surfaces on the top and bottom (both ends of the hole). Interfiber space 5
are filled with adhesive if necessary.

Needless to say, the fibers are not limited to those having a circular cross section, but may have various modified cross sections as required. Such materials include polyester, polyamide,
Polyurethane, polyvinyl compounds, cellulose, silicone, fluorocarbon resins, and the like are countless, and can be appropriately selected from known polymers.

As the island component or equivalent component to be removed, a polymer different from the sea component is selected, and such consideration is also given to the adhesive, which is further selected depending on the intended use.

Fibers are not necessarily of the same thickness (denier), but if the pore sizes are well matched, they can be mixed with fibers of different thickness (denier) to form a close-packed bundle. But it's okay.

The fact that the pore diameters are ``substantially'' the same means that even if there are 0.5 micron pores mixed in, such as a large number of 3 micron pores, the pores will actually be 3 micron in diameter. Therefore, it can be said that there are substantially well-aligned (3 micron) pores even in this case.

The present invention is particularly effective for pores with a diameter of 7 to 0.01 microns, and it is preferred that the pore diameters be substantially the same here. This corresponds to the number of islands, ie, the number of holes per island, which is preferably from 5 to 10,000.

In addition, the island component is not limited to a solid substance, but is preferably a material such as silicone or polyalkylene oxide, which has heat resistance, viscosity, and has fluidity at room temperature to enable high-speed spinning for the purpose of forming holes. Particularly preferred are those that exhibit fluidity at temperatures below 100°C.

This has the excellent feature that island components can be easily removed by extrusion or centrifugation using fluidity without dissolving or decomposing. It has the feature that even if there is a residue, it can be easily cleaned with a solvent.

In order to particularly increase efficiency, the island (pore) component ratio should be at least 50% of the total, and in particular, the maximum diameter of the pores formed therefrom should be 7 to 0.01 microns. By controlling the pore size, it is possible to remove particles of a certain size or larger very accurately. For example, the uniformity of the pores makes it suitable for removing particles of a specific size from blood.

In addition, large hollow fibers are generally easy to crush and curl, but according to the present invention, even if the hollowness ratio is the same, they are honeycomb-like hollow, so they have support and are generally difficult to crush and curl. Moreover, it can maintain a high hollow position.

By comparing the object and configuration of the present invention, the numerous features and effects of the present invention will be understood.

The products of this invention are extremely effective in a wide range of applications, including the various separation applications mentioned in the purpose of the invention, various retention of catalysts and enzymes, adsorption, sorption, heat insulation, and moisture permeability. It is.

Examples are shown next, but the effectiveness of the present invention is not limited to these, but rather brings about the following application development.

Example 1 Polystyrene was used as the island component, the number of islands was 145, polyethylene terephthalate was used as the sea component,
Using a composite spinning machine with an island component/sea component ratio of 60/40, the material was spun at a spinning temperature of 290° C., and spun into a polymer mutual array fiber at 1000 m/min. This material was hot drawn to obtain a 3D composite filament.

This composite filament was arranged into a tow shape, fixed with epoxy resin, and made into a rod shape. This material was cut approximately perpendicularly to the longitudinal direction to a thickness of about 1 mm, and then immersed in trichlorethylene and washed repeatedly to substantially remove the polystyrene to obtain an ultrafine porous continuous hollow fiber bundle. Ta.

The number of holes in each filament of the microporous plate that makes up this bundle is 145, which is the same as the number of islands, and the equivalent radius is r _eq ≒ 0.646 microns when calculated assuming the specific gravity of polystyrene is 1.05. When examined using a scanning electron microscope, it was found that they almost matched, and it was confirmed that, although small, they formed a microporous plate made of polyester.

Example 2 In Example 1, instead of the island component, heat-resistant, high-viscosity silicone was used for spinning. Perhaps because the viscosity at high temperatures was lower than that of polystyrene, the roundness of the island shape was distorted and there were some instability during long-time spinning, but as a sample,
It was possible to collect enough material and heat-stretch it as a composite filament.

Similarly, we investigated whether island components could be removed by forming bundles into stiff plates and then centrifuging them. Removal of the island components was observed at 3 to 5 G (acceleration unit of gravity), and to ensure completeness, cleaning was performed with the solvent trichlorethylene.

In this way, a microporous plate could be obtained in the same manner.

[Brief explanation of drawings]

FIG. 1 is an example of a model cross-sectional view of a microporous hollow fiber according to the present invention. In Figure 2, they are arranged in a bundle,
FIG. 2 is a cross-sectional view of a model of the ultrafine porous continuous hollow fiber bundle of the present invention, showing the part where the fiber bundle is bundled and has planar holes at both ends. 1, 3... Micropore, 2... Hollow fiber, 4... Fiber,
5... Interfiber space.

Claims (1)

[Scope of Claims] 1. A large number of fibers each having a maximum pore diameter of ultra-fine 7 to 0.01 microns, and each fiber having a large number of independent continuous micropores parallel to the fiber axis and having substantially the same pore diameter. 1. An ultra-fine porous sheet-like plate, which is formed by being aligned in a shape, fixed with a fixing agent, and integrated, and having a cut surface with planar holes at both ends of the holes. 2. A large number of sea-island type fibers having a large number of islands with a diameter of 7 to 0.01 microns consisting of at least two components are arranged into bundles and fixed and integrated with a fixing agent, and then the top and bottom are cut into planar shapes, and then the island components are 1. A method for producing an ultra-fine porous sheet-like plate, characterized by removing the holes. 3 The island component is spinnable and exhibits fluidity rather than solidity at least at room temperature, and the sea component is made of a plastic material that retains its solidity sufficiently at lower temperatures, and the island component is made into a fluid state. 3. The method for producing an ultrafine porous sheet plate according to claim 2, wherein the removal is carried out by at least extrusion or centrifugal force.