JPH0548695B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing an artificial blood vessel formed into a tube of fibers and having uniform fraying resistance and excellent anastomotic properties through fluid treatment. .

[Prior Art] Conventionally, it is known to subject a planar woven or knitted fabric to high-pressure fluid treatment. However, it is difficult to simply apply high-pressure fluid treatment to a tube-shaped artificial blood vessel because the tube is integrated. In order to avoid this, the present inventors have already separately discovered a method in Japanese Patent Application Laid-Open No. 61-92666, in which a shield is placed inside the tube and high pressure treatment is performed.

However, although this method achieves its intended purpose, it also tends to cause the shield and tube to become misaligned due to high-pressure treatment, or streaks are likely to form on both sides of the tube in the diametrical direction due to uneven fiber entanglement, resulting in fluctuations in diameter. It was found that this caused a big problem from a quality control perspective.

[Problems to be Solved by the Invention] Artificial blood vessels made of knitted fabrics tend to fray after passing through a sewing needle or when connected to living blood vessels, resulting in anastomotic failure. Therefore, various improvements have been made, which have made the knitting structure more complicated and required special knitting machines. For fabrics, high-pressure fluid treatment was performed with a shield placed inside the tube to improve the prevention of fraying, but the treatment resulted in uneven treatment, dimensional deformation, and radial The streaks on both sides were conspicuous.

The present inventors have arrived at the present invention as a result of intensive study on the above-mentioned problem, which is a fatal defect in artificial blood vessels.

[Means for solving problems] The present invention has the following configuration.

(1) When performing high-pressure fluid treatment on a cylindrical fibrous sheet, the cylindrical fibrous sheet inserted into the mandrel and the high-pressure fluid injection section are rotated relative to each other, and the cylindrical fibrous sheet is rotated relative to the high-pressure fluid injection section. A method for manufacturing an artificial blood vessel, characterized by performing high-pressure fluid treatment by relatively advancing it in parallel or cross directions.

(2) The method for manufacturing an artificial blood vessel according to claim 1, wherein the high-pressure fluid treatment is performed while slightly vibrating the cylindrical fiber sheet in which the mandrel is fitted and/or the high-pressure fluid jetting section.

In the present invention, the tube formed from fibers may be any of woven fabrics, knitted fabrics, braids, nonwoven fabrics, etc., and can be arbitrarily selected regardless of the type of tissue. Further, the fibers may be one type of fiber, or two or more types of fibers may be mixed or aligned. Also, although it is acceptable to use one type of thread during the formation of the basic structure, it is more preferable to use two or more types of thread. For nonwoven fabrics, it is preferable to use general card M/C, flash spinning, melt blowing, air injection (OF), or the like.

Polymers used as fibers include polyester, polyamide, polytetrafluoroethylene,
Although it does not matter what kind it is, such as polyolefin,
Particularly preferred is polyester. When using multi-component fibers, the final polymer remaining is the above-mentioned polymer, but other combination components include polystyrene, polyethylene, water-soluble polyamide, alkaline aqueous solution-soluble polyester, water-soluble polyvinyl alcohol, etc., as appropriate. is possible.

In order to make the present invention more effective, at least some of the fibers constituting the tissue have a single fiber fineness.
It is best to use ultrafine fibers of 1.0 denier or less.
By using ultrafine fibers, the three-dimensional confounding effect due to high-pressure flow, which will be described later, is enhanced, and the artificial blood vessel becomes extremely flexible.

Regarding the ultrafine fibers mentioned above, when forming blood vessels, fibers that are already in the form of ultrafine fibers may be used as they are, but tubes can be formed using fibers that can be made ultrafine by chemical or physical means. However, the tube may be formed by ultrafine fibers by subsequently making the fibers ultrafine. Ultrafine fibers can be obtained by using ordinary spinning methods with due care.
As in the case of polyester, it is also possible to draw undrawn yarn under specific conditions to form ultrafine fibers.

On the other hand, examples of fibers that can be made ultrafine by post-processing include Japanese Patent Publication No. 48-22126 and Japanese Patent Publication No. 53-22593.
It refers to a type of fiber that is fibrillated or made ultra-fine by removing or exfoliating one component of a multicomponent fiber, as seen in the above publications. In the case of such fibers, during tube processing, even if the fiber is of normal thickness, it can be made extremely fine after processing, which may cause problems during processing, such as during weaving, knitting, stringing, and various thread processing before weaving or knitting. This is preferable because yarn breakage, fuzz generation, etc. can be minimized even when measures are taken.

Next, the cylindrical fibrous sheet is subjected to high-pressure fluid treatment, and it is desirable that the tube surface of the cylindrical fibrous sheet have raised naps before being subjected to the high-pressure fluid treatment.

The cylindrical fiber sheet used in the present invention is applied to the surface of woven fabrics, knitted fabrics, woven fabrics, etc. by, for example, a method using a raising machine, a method using a shearing machine, a method of rubbing with sandpaper, a method using fancy yarn, etc. A knitted fabric having a lot of fluff can also be used. By subjecting these raised cylindrical fiber sheets to high-pressure fluid treatment, an artificial blood vessel with excellent fraying resistance and anastomotic properties can be obtained.

In the method for manufacturing an artificial blood vessel according to the present invention, the mandrel to be fitted into the cylindrical fiber sheet is made of stainless steel,
It is preferable to use rods or tubes made of plastic, iron, glass, rubber, etc. Furthermore, there is no problem even if the rod pipe is a wire-mesh-like tube. The diameter may be appropriately selected according to the inner diameter of the artificial blood vessel.

If the rotational speed of the cylindrical fiber sheet fitted into the mandrel and the high-pressure fluid injection part is too fast, it will be inferior in terms of entanglement, and if it is too slow, it will lead to cutting or damage of the fibers, so the rotational speed should be between 0.1 m/min and 10 m/min. A range is preferred.

Next, the processing pressure of the high-pressure fluid is preferably 5 to 200 kg/cm ² from the viewpoint of safety and economy. If the pressure is too low, a sufficient entangling effect will not be obtained, and if the pressure is too high, the fibers will break, causing undesirable problems, so the preferred range is 10 to 100 kg/cm ² .

A columnar flow or a spray flow can be used as the jet fluid. A thin linear columnar flow is preferred to achieve the objectives of the present invention. Spray flow is inferior in terms of entanglement, but it can be used to solidify the foundation of entanglement and for surface finishing. Therefore, by using appropriate combinations of spray flow rather than columnar flow alone, it is possible to improve the surface finish with uniform entanglement. It becomes smooth.

The hole diameter of the nozzle for injecting the fluid is 0.05 to 1.0 mm, preferably 0.1 to 0.5 mm, and the hole pitch is preferably 0.5 mm to 5 mm apart from the viewpoint of durability depending on the hole diameter.

The appropriate distance between the injection hole and the cylindrical fiber sheet is 10 mm to 70 mm; if the distance is too large, the columnar flow will turn into a spray flow, resulting in poor entangling properties, which is not preferable.

The processing direction of the cylindrical fiber sheet is perpendicular to and parallel to the high-pressure fluid jetting section, or perpendicular to and crosswise to the high-pressure fluid jetting section for uniform entanglement and efficiency.

Further, the cylindrical fiber sheet and the fluid jetting section are moved relative to each other. This relative movement means either limiting the position of the fluid ejecting part and rotating the cylindrical fiber sheet itself, or vice versa, in which the fluid ejecting part rotates and moves along the outer circumference of the cylindrical fiber sheet. That's a good thing. If it cannot move, the high-pressure fluid will be concentrated in one place, resulting in damage to the cylindrical fiber sheet. Therefore, the moving speed is appropriately determined depending on the pressure of the fluid, the rotation speed, etc. Preferably it is 10 mm to 500 mm/min.

To make the invention even more useful, the cylindrical fiber sheet and/or the high-pressure fluid jet fitted into the mandrel are subjected to relative microvibrations.
By combining rotation and this vibration, punch streaks and moire phenomena can be further reduced.
The surface condition of the resulting artificial blood vessel is also smooth. Furthermore, it has become possible to uniformly treat the entire cylindrical fiber sheet with high-pressure fluid.

The frequency of the minute vibration is not particularly limited, but it is preferably in the range of 0.1 to 50Hz, and the vibration direction is back and forth,
It can be vibrated either left or right. It is also okay to vibrate cyclically. The amplitude may be appropriately selected depending on the pitch interval of the nozzle holes and the vibration frequency, but it is preferably in the range of 0.5 mm to 50 mm. Further, as the waveform used for vibration, a triangular wave, a sine wave, a trapezoidal wave, etc. are used.

It is possible to further improve the fraying resistance by turning the tube-shaped article processed by these methods and processing it again using the same processing method, but this is not always necessary.

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

Example 1 The warp yarn and the weft yarn (back yarn) were made of polyethylene terephthalate 50 denier 24 filament temporarily twisted yarn, and the weft surface yarn was a polymer array composite fiber containing 78 parts of island component polyethylene terephthalate and sea component polystyrene 22. 245 denier 40 filament fiber with 36 islands is used, so-called history 2
Heavy woven structure, tube-shaped, inner diameter 19mmφ, length
A 100 cm cylindrical fiber sheet was formed, washed with hot water, and then dried, and the polystyrene was removed with perchlorethylene. Next, a napping treatment agent was applied to this tube, and then the tube was napped using a napping machine.

A stainless steel rod was inserted into this tube, connected to a constant speed motor, and rotated at a speed of 0.25 cm/min. Fluid discharge hole diameter 0.25mmφ, discharge hole interval 2.5mm,
Waterjet punching was carried out under the following conditions: a pressure of 80 kg/cm ² , a distance from the tube of 40 mm, a nozzle head vibration frequency of 3 Hz, and a vibration width of 10 mm, and the cylindrical fiber sheet was cut in a direction parallel to the nozzle head. In the obtained artificial blood vessel, it was observed that a large number of ultrafine fibers were uniformly intertwined between single fibers, between weaves, and between fiber bundles. In addition, no unevenness in the diameter of the obtained artificial blood vessel was observed, and no streaks due to uneven fiber entanglement were observed.

After cutting the artificial blood vessel at a 45° angle with a knife, a suture was passed 2 mm from the tip and the fraying of the stump was examined. No fraying occurred.

Comparative Example 1 The same yarn was used as in Example 1, and the raising was carried out in the same manner. A polyester film with a thickness of 0.12 mm was inserted into the tube as a barrier and conveyed on a wire mesh conveyor at a speed of 0.25 cm/min. Fluid discharge hole diameter 0.25mmφ, discharge interval 2.5mm,
Waterjet punching was carried out at a pressure of 80 kg/cm ² , a distance from the tube of 40 mm, a nozzle head vibration frequency of 3 Hz, and a vibration width of 10 mm, set in a direction transverse to the nozzle head. In the obtained artificial blood vessel, it was observed that a large number of ultrafine fibers were intertwined between single fibers, between weaves, and between fiber bundles, but streaks due to uneven fiber entanglement were observed on both sides in the diametrical direction.

After cutting the artificial blood vessel at an angle of 45° with a knife, a suture was passed 2 mm from the tip and the stump was examined for fraying. In addition, a cut was made so that the muscle part was at the tip, and a suture thread was passed through a 2 mm point to check for fraying. As a result, there was almost no fraying in the non-stripe portions, but there was considerable fraying in the sinew portions.

Example 2 3.6 denier, 51 mm polymer array fiber consisting of polyethylene terephthalate as the island component and polystyrene as the sea component (weight ratio of island component: 50c%, number of islands: 18)
A card M/C was passed through the Gahara cotton consisting of the following. This was followed by needle punching. The fabric weight of the obtained nonwoven fabric was 10 g/m ² . This was soaked in trichlene and squeezed with a mangle to remove the polystyrene component. The basis weight at this time was 5 g/m ² . Afterwards, this non-woven material was hand wrapped around a stainless steel rod. The number of turns was 8. This rod was connected to a constant speed motor and rotated at a speed of 0.25 m/min. The liquid discharge hole diameter was 0.25mmφ, the distance between the discharge holes was 2.5mm, the distance between the injection holes and the non-woven fabric tube was 20mm, the vibration frequency of the nozzle head was 3Hz, the vibration width was 10mm, it was set parallel to the nozzle head, and the injection pressure was initially 10Kg/ ^cm2 . .
Next, processing was carried out by increasing the pressure gradually to 20Kg/cm ² , then 30Kg/cm ² , 50Kg/cm ² , and finally 70Kg/cm ² . It was observed that in the obtained artificial blood vessel, a large number of ultrafine fibers were evenly intertwined.

After cutting the artificial blood vessel at an angle of 45° with a knife, a suture was passed 2 mm from the tip.
I inspected the residual limb for fraying. Those that were not treated with waterjet frayed easily, but those that were treated hardly frayed.

[Effects of the Invention] By adopting such a configuration, the present invention brings about the following extremely large effects.

(1) Uniform high-pressure fluid treatment can be applied to the entire surface of the artificial blood vessel, resulting in uniform fraying resistance and excellent anastomotic properties.

(2) Problems in quality management (unevenness in diameter, streaks due to uneven fiber entanglement, smoothness of the surface) are resolved, yields are improved, and work efficiency is increased.

(3) Loss and floating hair caused by the piloerection process can be washed away or substantially eliminated by fine entanglement.

Claims (1)

[Claims] 1. When performing high-pressure fluid treatment on a cylindrical fibrous sheet, the cylindrical fibrous sheet fitted into the mandrel and the high-pressure fluid injection section are rotated relative to each other, and the cylindrical fiber sheet fitted into the mandrel is rotated relative to the high-pressure fluid injection section. 1. A method for producing an artificial blood vessel, which comprises performing high-pressure fluid treatment by relatively advancing a shaped fiber sheet in a parallel direction or a cross direction. 2. The method for manufacturing an artificial blood vessel according to claim 1, wherein the high-pressure fluid treatment is performed while slightly vibrating the cylindrical fiber sheet into which the mandrel is fitted and/or the high-pressure fluid jetting section.