JPS6227191B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for making ultrafine plastic tubes having fine interconnected pores.

Hollow fibers of normal thickness are already known. There is also evidence that it has already been considered as a fiber to create a silk-like texture and as a fiber for futon cotton.

However, ultrafine plastic tubes that are extremely thin and extremely homogeneous are not known. Fibers that are so thin as to be less than 1 denier, preferably less than 0.7 denier in terms of denier, and that have fine, uniform continuous pores therein have not yet been known.

This is probably because the manufacturing method for such ultra-fine plastic tubes was too difficult to realize.

The present inventor believes that such ultrafine tubes can be used in various separation operations, such as separation of industrial particles, separation of specific dirt, filters, medical separation, such as separation of specific particles in blood, and other applications. If you think about things like heat and cold storage from a different angle, you can think of countless applications, and in turn, it will make a huge contribution to humanity, leading to industrial and medical uses that will save countless lives. It is an object of the present invention to provide such a basic material.

Other purposes will become clear in later explanations.

The gist of the present invention is as follows.

At least two of the fibers consisting of at least three constituent parts have a sea-island structure in cross section, and at least one of the remaining fibers is present in the island component and is continuous in the longitudinal direction in a core-sheath shape, The core component is liquid at room temperature, and the pod component in the island is
A method of producing sea-island type composite fibers having a melting point or softening point higher than 100℃ and removing the sea component and core component, which involves applying pressure to the core component in the islands from one side before or after removing the sea component. Alternatively, a method for producing ultra fine plastic tubes characterized by removal by centrifugal force.

These completely new materials and their manufacturing methods will be explained in more detail.

The conventional manufacturing method for ultra-fine fiber itself is quite difficult, and although this has recently been overcome, it is true that it depends on a special spinning method. Moreover, making it hollow was even more difficult, and no such idea was even thought of.

The present invention focuses on the effectiveness of ultrafine plastic tubes and clarifies the manufacturing method for actually obtaining them.

Although the conventional hollow spinning method of the present invention, in which the polymer is discharged while introducing air or gas, is effective for thick denier fibers, no attempt has been made to apply it to ultra-fine denier fibers. Even if you try, it is almost useless, much less uniformity, stability,
Adding the perspective of reproducibility, it turned out to be very difficult. The present inventor focused on three-component composite spinning technology and succeeded in easily achieving the object of the present invention and also revealing an innovative manufacturing method.

It must be particularly noted that the present invention is, of course, effective not only for hollow fibers of conventional thickness and hollow fibers of thinner thickness, but also for hollow fibers or tubes much thinner than these. .

The present invention, while skillfully utilizing a three-component composite spinning technology consisting of at least three components, completely changes the conventional idea and succeeds in obtaining a basic material that has not been previously available. The three-component spinning technology has already been disclosed by the present inventors in a separate patent application (Japanese Patent Application Laid-Open No.
54-116417, Japanese Patent Application Laid-open No. 56-20608).

The fiber cross section obtained thereby is, for example, the first
As shown in the figure, there is an island component B in the sea component (C in the diagram).
are present in large numbers, and the core component A is present in the islands B (which can also be said to be one of the island-core-sheath type polymer mutually arranged fibers).

Here, it has been discovered that if the C and A components are removed, an ultrafine plastic tube consisting of the B component can be obtained.

Denier is used for fibers to correspond to the thickness, and in the present invention, 1 denier or less is preferably used, and more preferably 0.7 denier or less. For hole diameters and deformed ones, the maximum cross-section diameter is used, and the maximum is 10
microns or less, more preferably 6 microns or less,
0.01 micron or more is preferable.

Pores can also be one to two orders of magnitude smaller than 10 microns. The number of islands is 1 to 10,000, preferably 5 to 1,000, and more preferably 10 to 250.

Since the cross-sectional example of FIG. 1 is continuous in the longitudinal direction, the ultrafine plastic tube obtained therefrom is a substantially continuous and uniform ultrafine plastic tube in the longitudinal direction as illustrated (cross-section) in FIG. It's tube.

This method has the advantage of yielding extremely uniform products and allowing a predetermined separation operation (which in chemical engineering is sometimes referred to as classification in a broad sense) to be carried out. For example, if you want to standardize the pore diameter to 5 microns, you can standardize it to the desired diameter by controlling the density of the spinning components, the polymer pump feeding into the spinneret, take-up speed, stretching ratio, and post-shrinkage. What attracts attention is that it is possible.

Examples of materials include polyethylene terephthalate, polybutylene terephthalate, nylon 6, 66, 610, 11, 12, nylon containing PACM as a polymerization component, polypropylene, polyethylene, polyurethane, etc. Needless to say, the above-mentioned polymers also include copolymerized polymers with other components. There is no end to the list here, and they are selected to take advantage of the characteristics of the polymer at the time.

On the other hand, the sea component C is, for example, polystyrene, polystyrene copolymer such as polystyrene copolymerized with 2-ethylhexyl acrylate, copolymerized polyester such as copolymerized polyethylene terephthalate such as 5-sodium sulfoisophthalate,
Examples include polyethylene, polyurethane, silicone, and polyalkylene oxide.

When the ultrafine plastic tube thus obtained is used for separation, if the fine particles are not deformed, all particles other than a predetermined size will pass through, but all larger particles will not pass through. Furthermore, even if all of the objects are larger than a predetermined value, in the case of a mixture of deformed objects, only those objects will pass through. This also applies to efficient separation of blood. Furthermore, when used for heat or cold insulation, microfibers generally have very good heat retention properties as a group, but according to the present invention, since the microfine fibers contain air layers even within the microfiber groups, they have even better heat insulation properties. In addition, by using these capillaries, it is possible to create products that are highly breathable but do not allow water to pass through, or products that have high water retention properties.

Such demands are seen in the industrial field, the household materials field, the medical field, the clothing field, and the agricultural field.

The above three-component composite fiber is spun as a fiber of normal denier as a whole, and is normally drawn, drawn,
Heat set and cut if necessary.

Methods for obtaining ultra-fine plastic tubes from such component fibers include (a) a method of removing the sea component, further removing core component A, and selectively leaving component B (note that all the sea components are island components); It is specifically noted here that the present invention is not limited to the type of fibers that cover the fibers. or (b) a method of removing the core component and removing the sea component. These removals include physical,
Although there are chemical means, usually removal by dissolution and decomposition are considered, but dissolution and decomposition are not the only methods, and there are other new methods, and these are as follows.
I will explain later.

Furthermore, a manufacturing method particularly suitable for obtaining the ultrafine plastic tube of the present invention will be described.

In the present invention, the core component A in the island component is non-solid at 100°C or less and liquid at room temperature, and the core component A in the island is processed from one side before or after the removal of the sea component. This is a method of removing by pressure or centrifugal force. According to this method, the core component A is
It has an innovative feature of high industrial value: it can be heated to below 100°C (normal steam bath) or poured out extremely easily at room temperature. The reason for this is, for example, a method of removing the fluid component of the core component using only a solvent, as disclosed in JP-A-53-78323, but since the pores corresponding to the core component are extremely thin and long, It is extremely difficult to get the solvent in and out using a method that removes it with only one tool. Therefore, the core component practically requires extremely long cleaning times.
It has no industrial value. Thereafter, washing can be further performed by applying pressure or the like with the aid of a solvent if necessary. In any case, it goes without saying that a cut end is necessary. At this time, the plastic island component must not have a melting point or softening point so low that it will melt when heated below 100°C. It must be noted that the liquid state of the wick has the advantageous property of being able to be removed by suction, unilateral pressure, or even by centrifugal force, which is easy to effect.

A typical core component A that is easy to spin, stable against heat, and in a liquid or semisolid state at room temperature is silicone.

Silicone is an example of a preferred polymer for achieving this purpose, as it is available in a variety of different degrees of polymerization (viscosity). Unlike polyalkylene glycols, it is also superior in that it does not decompose due to heat. I will also explain that I have found other means. One method is to make the core an elastic material such as polyurethane. Such a material can be pulled out as long as the drawer is tightened from the cut surface, and the diameter of the elastic body becomes thinner by pulling out. Such a method can be used effectively when the length of time is not too long.

The other method, which is quite difficult to spin, is to use a sublimable substance for the core and sublimate it.

It has been found that when the ultrafine plastic tube obtained according to the present invention is used for separation purposes, it is very effective to bundle it into a bundle and have cut ends on both sides. This product is made by bundling tows before forming into tubes, fixing and cutting each tow, and then forming each tow into a tube, or by bundling, fixing, and cutting the tubes.

Tow is great because it can be pulled, aligned, and rolled.

Furthermore, it goes without saying that such tubes can be used in a state where they are bound together with a binder, a filler, or the like. As a method for obtaining such a bundle, the most economical and preferable method is to remove only the core component of the island-core-sheath type sea-island fibers as described above.

Furthermore, in different applications, such as those in which such tubes are bundled and strongly bent, or applications in which it is difficult to show strong resistance when bending, sea C is used.
A method in which the component is an elastic body such as urethane rubber, silicone rubber, fluorocarbon rubber, or various natural or synthetic rubbers and in which this component is not removed is extremely superior. This is because not only are these flexible tube bundle fibers already aligned during three-component spinning, but also these flexible tube bundle fibers can be rebundled to form a higher quality bundle.

Furthermore, if a non-woven fabric of the above-mentioned composite fibers is made, the voids between the fibers are filled (adhered) with resin, and then sliced to form two or more cut surfaces, a large number of hollow holes of the tube penetrate between both surfaces. A separation structure is obtained. Furthermore, if woven or knitted fabrics are laminated and bonded and then sliced into sheets at right angles to the laminated surfaces, a separation structure with a geometric structure can be obtained. By this method,
A structure can also be created in which the tubes are arranged perpendicularly to the plane and the reinforcing fibers are arranged in the plane direction. Of course, they can also be laminated to form a sheet-like structure with high strength both vertically and horizontally. In manufacturing such a structure, the core component can be removed at any stage before or after forming the sheet, or before or after slicing. Sea components are also removed if necessary.

Let's use diagrams to make it easier to understand. FIG. 1 is an example of a cross-section of a sea-island type fiber that best achieves the present invention. In Figure 1, C is the sea component,
B is an island component, and A is contained therein as a core component. The ratio of (B+A)/C can be from 1/99 to 99/1, but more stably from 1/99 to 97/4, preferably from 50/50 to 97/4 from the viewpoint of yield. When it becomes 90/10 or more, the island component exhibits a square shape due to the close-packing relationship.
3 to 8 sides, usually about 4, 5, or hexagons. With three-component spinning, the core diameter can be very well controlled.

The A/B ratio can range from 1/99 to 99/1, but a more stable range is 1/99 to 95/5. good.

The island component B is not necessarily completely surrounded by the sea component C (this also includes a separation type complex state). Preferably, it is spun in at least several bundles.

From Figure 1, when both CA components are removed, the second
An ultra fine plastic tube as shown in the figure is obtained.

(Note: The term microfine generally refers to something like powder that has been cut into very fine pieces for electro-flocking or paper, and refers to the fineness in terms of length.) 2 shows the cutting of a hollow ultra-fine plastic tube with a

Such materials are bundled as shown in FIG. 3 and used for separation purposes. At this time, it is preferable that the hole diameter (the width across the largest part) be the same as or larger than the diameter across the maximum width of the space created between the bundles. This is because, for separation purposes, it is better to separate through holes with controlled diameters and not allow anything else to pass through.

Otherwise, it is preferable to use a binder or filler to fill the gaps between the bundles.

Figure 4 shows the original tube bundle as it is (for example, only the A component has been removed).
are doing.

It has already been mentioned that especially when the C component is an elastic polymer, it is very good in terms of bending. In particular, it is preferable to process from the state shown in FIG. 1 to the state shown in FIG. 4 all at once.

It was considered that component A could be made as a gas from the beginning, but it turned out to be extremely difficult to manufacture such ultra-fine plastic tubes. Not only that, but in terms of uniformity, stability, diameter control, stable productivity, and fine spinning, using the gas as it is is extremely inferior, and even if you think about it later in your head, it is extremely inferior. , in reality no one has succeeded. Especially if the number of islands is 3 or more, A+B/A
+B+C is 0.30, preferably 0.50 or more, and the present invention is extremely thin, with a pore diameter of 10 μm or less, something that could not even be imagined.

These ultra-fine incubators not only have extremely high heat retention properties, but are also lightweight and can be used for insulation purposes as wadding, paper, and non-woven fabrics.The pore diameter can be made smaller, so by lowering the pore size further, blood can be absorbed. It can also be applied to separation, separation of smoke and smoke-like substances, separation of bacteria and viruses, adsorption and sorption of specific substances, various types of filtration, and separation of emulsions and colloids.

Note that even if component B is partially removed during separation and removal of component C or component A, the effectiveness of the present invention will not be impaired in any way. Further, even if the C component or the A component is not completely removed (theoretically it is extremely difficult to achieve 100%), it is sufficient as long as the object of the present invention is substantially satisfied.

To explain the former example, when polyethylene terephthalate is the B component and a copolymer of 5-sodium (or lithium or potassium) sulfoisophthalate is the C component, when removing and cleaning with an alkali, A and C are removed extremely quickly. Although it is said that it is easy to dissolve, component B is also removed to some extent at the same time. B to polybutylene terephthalate
This is because if the components are removed, the B component will become even more difficult to dissolve, but it will still be necessary to say that some B component will also be removed. Preferably, it is easy to select from the group of polymers mentioned above those having a large difference in solubility or degradability.

Examples will be shown next, but the present invention is not limited or has its effectiveness restricted by these examples, but rather brings about the following application development.

Example 1 The following three-component composite fiber was obtained using a sea-island type three-component composite spinneret (disclosed in Japanese Patent Application Laid-open No. 116417/1983) in which the island component has a core-sheath type structure.

Spinning temperature: 280℃ Take-up speed: 1000m/min Stretching ratio: 2.8 Core component (A): Silicone oil with viscous fluidity at room temperature Island component (excluding core) (B): Polyethylene terephthalate Number of islands: 16 islands Sea component :2-ethylhexyl acrylate
22wt% copolymerized polystyrene Core component ratio: 20 Island component ratio (excluding core component): 40 Sea component ratio: 40 Obtained fiber denier: Approximately 4 This filament is put into a skein, made into a tow shape,
Sea components were removed by washing with trichlorethylene.
The ends of the bundle of tow were fixed with epoxy resin, left to solidify for 2 days, cut with a sharp blade so that openings were made at both ends of the fibers, and each set of approximately 9 cm of fibers was centrifuged.

As a result, most of the silicone liquid in the core can be removed without using any solvent (as shown in the model diagram in Figure 4).
A bundled ultra fine plastic tube was obtained.

Furthermore, this ultra-fine plastic tube was washed inside and outside the hole with trichlorethylene by applying pressure from one side over and over again, to obtain an ultra-fine plastic tube. This material had a diameter of approximately 41 microns and an inner diameter of approximately 2.7 microns.

[Brief explanation of the drawing]

FIG. 1 is an example of a model diagram of a sea-island fiber cross section most suitable for achieving the present invention. FIG. 2 is an example of a cross-sectional model diagram of an ultrafine plastic tube according to the present invention. FIG. 3 is a model diagram in which the ultrafine plastic tubes according to the invention are bundled into a bundle and have cut surfaces necessary for separation operations. FIG. 4 is a model diagram showing a state in which ultrafine plastic tubes are bundled together by other components (which can be said to be island-hollow polymer mutually arranged fibers).

Claims (1)

[Claims] 1 At least two of the fibers consisting of at least three constituent parts have a sea-island structure in cross section, and at least one of the remaining fibers is present in the island component and is continuous in the longitudinal direction in a core-sheath shape, and further has at least one island structure. This is a method of creating a sea-island type composite fiber in which the core component inside is liquid at room temperature and the sheath component in the islands has a melting point or softening point higher than 100℃, and the sea component and core component are removed. A method for producing an ultra-fine plastic tube, characterized in that the core component in the island is removed by pressurization from one side or centrifugal force before or after the removal of the component.