JPH0652265B2 - Medical small diameter flexible tube and manufacturing method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a medical small-diameter flexible tube and a method for producing the same, and particularly to diagnosing a disease of the blood circulation system by observing a modified form of red blood cells. The present invention relates to a medical-use minute diameter flexible tube having an inner diameter of several μ applicable to an inspection method to be performed and a manufacturing method thereof.

[Background technology]

In recent years, a groundbreaking test method for observing the morphology of red blood cells and examining diseases of the blood circulation system such as heart disease has been developed by the Heavy Ion Society (GSI) of West Germany. This test method collects human blood and takes out red blood cells, puts the red blood cells in a container composed of a thin film having a large number of holes having the same inner diameter as the thin portion of human capillaries, and when the red blood cells pass through the holes. It measures time and quantity. The size of human red blood cells is in the range of 7 to 8 μ, and the inner diameter of the thin portion of the capillary is around 5 μ. Red blood cells of a healthy person
Although even such a thin portion (capillary blood vessel) changes its shape and passes through, red blood cells of a person suffering from a disease of the heart or circulatory system are difficult to pass through because of their poor deformability. Based on this, the diagnosis of heart and blood circulation system diseases is performed from the measured values.

The plastic thin film used in this inspection method has a hole having the same inner diameter as the inner diameter (around 5 μm) of the thin portion of the capillary as described above. Specifically, a heavy ion (heavy particle beam) accelerated by a linear accelerator used for the study of atomic physics is applied to a thin plastic (for example, polycarbonate) film having a thickness of several tens of μ, and the pore diameter is 3 to 5 μm. The one with the holes formed is used.

[Problems to be Solved by the Invention]

Although it is possible to form fine holes of several μ by this method, the accuracy of the hole diameter has a fluctuation of 10% or more, and it is difficult to manufacture a large number of holes with a constant hole diameter. There was a problem to say. Also, the equipment for forming a large number of fine holes in the plastic thin film is still in the research stage and is not generalized because it is used in atomic physics, and therefore the plastic used in this inspection method is There is a problem that it is difficult to obtain a thin film. Furthermore, since the pore diameter of the plastic thin film is unstable, even when an inspection is performed using a container made of the plastic thin film, there are variations in the time taken for red blood cells to pass through, variations in morphology, viscosity, etc. There is also a drawback that an accurate pathological diagnosis cannot be obtained.

Therefore, an object of the present invention is to observe a deformed erythrocyte and to apply it to a test method for diagnosing a blood circulation system disease. Is to provide.

It is another object of the present invention to provide a medical small-diameter flexible tube that can easily perform a test for diagnosing a blood circulation system disease and can obtain a highly accurate test result.

Another object of the present invention is to provide a method for manufacturing a medical-use minute diameter flexible tube which does not require a highly accurate jig and tool and has high dimensional accuracy easily.

By the way, the medical small diameter flexible tube of the present invention cannot be manufactured by a conventional extrusion molding method.
That is, when making a tube with an inner diameter smaller than 25μ, it is difficult to machine jigs and tools (dies, nipples, etc.) with dimensions that correspond to minute tube dimensions, and the machining accuracy is the accuracy of the tube dimensions. Since it becomes lower, it is difficult to manufacture a small diameter flexible tube having an inner diameter of 25 μm or less. Some small-diameter flexible tubes are manufactured by Zeus (a US plastic resin processing manufacturer), but the smallest is a crystalline polymer resin of fluorocarbon resin with an inner diameter of 25μ and a wall thickness of 38μ. Met. In addition, when a small-diameter flexible tube is manufactured by pulling down an extruded hollow tube, there is a disadvantage that the outer diameter, inner diameter, and wall thickness of the tube vary depending on the pulling-down accuracy.
Furthermore, even if it is manufactured using a die, nipple, etc. with high dimensional accuracy, the resin amount per unit length is very small, so the amount of resin melt-extruded from the extruder is controlled (rotating speed of the extruder screw). It becomes difficult to control and control in the die part), and the outer diameter, inner diameter, and wall thickness of the tube fluctuate, and it is impossible to manufacture a small diameter flexible tube having a predetermined dimensional accuracy. Further, a micro-diameter catheter has been proposed by Japanese Patent Laid-Open No. 55-125878, but since it has an inner diameter of 80 to 200 μ, it cannot be used as a micro-diameter flexible tube for passage of red blood cells.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention comprises forming a coating by coating a crystalline polymer resin on a core having a minute outer diameter to a predetermined thickness, and then removing the core from the coating. , A crystalline polymer resin flexible tube is made, and the flexible tube is stretched in the longitudinal direction to reduce the diameter by several μ.
It enables the production of a flexible tube having an inner diameter of, and is applied to the diagnosis of heart disease and the like.

That is, the medical small-diameter flexible tube of the present invention is made of a crystalline polymer resin, has an inner diameter of several μ and a wall thickness of several tens μ, and further has red blood cells in the tube inner hole at one end thereof. It is provided with a housing which serves as a receiving member for passing through.

Further, the method for producing a medical-use minute diameter flexible tube of the present invention includes the following steps.

(1) Extrusion Molding Step A core having a predetermined outer diameter is coated with a crystalline polymer resin to a predetermined thickness to form a coating. The reason why the core body having a predetermined outer diameter is used here is to stabilize the inner diameter accuracy, and the core body portion becomes the inner diameter portion of the tube by being removed in the core body removing step described later. As the core body, one having a large tensile strength is used so as not to be broken by the tension during extrusion molding (for example, a tungsten wire is used). The crystalline polymer resin is used in the stretching step described later to reduce the diameter by stretching the tube, the molecules are oriented in the stretching direction, and the transparency is increased to facilitate the observation of red blood cells, and By increasing the strength, sufficient strength can be obtained even with a tube having a small diameter. Specifically, PE (polyethylene), P
ET (polyethylene terephthalate), PA (polyamide), PP (polypropylene), FEP (perfluoroethylene propylene), PFA (perfluoroalkoxy), ETFE (ethylene-4 fluoroethylene), PVD
F (vinyl denfluoride) or the like can be used.

(2) Core body removing step The core body is removed from the coating body to form a flexible tube of crystalline polymer resin. Specifically, after cutting the coating body to a predetermined length, the coating bodies at both ends thereof are peeled off to expose the core body,
Both ends of the exposed core body are grasped and tensioned to cut and remove the core body.

(3) Stretching Step The flexible tube produced by removing the core body from the covering body is stretched in the longitudinal direction to reduce the diameter to produce a small diameter flexible tube. The crystalline polymer resin has both elasticity and viscosity, and stress (stretching) in the elastic region
In the case of, there is a restoring property, and when a stress exceeding this is reached to reach the viscous region, intermolecular slip and molecular destruction occur and it becomes impossible to restore. It is well known that the yield point is at the boundary between these two areas, and the yield point can be remarkably confirmed in this boundary area. If a tension is applied to a tube made of a crystalline polymer resin at a yield point or higher and in a range that does not cause breakage, the tube is reduced in diameter and thickness by stretching. Further, when the molded product of the crystalline polymer resin is stretched, the molecules are oriented in the stretching direction to increase the crystal part having a strong molecular bond, and the intermolecular attractive force is increased, and the stretched part is larger than the non-stretched part. It has a characteristic that the elongation becomes extremely low, but the strength increases, and when all the stretched parts reach the state of the yield point or higher, they are not deformed by external stress. The present invention utilizes this feature to form a small diameter flexible tube by reducing the diameter in a drawing process. Further, in order to facilitate the stretching, it is preferable to apply tension while heating at a temperature below the melting point of the crystalline polymer resin. For example, when FEP resin is used as the crystalline polymer resin, 80 to 100
Perform in an atmosphere of ℃.

Hereinafter, the medical small diameter flexible tube of the present invention and the method for producing the same will be described in detail.

〔Example〕

FIG. 1 shows a medical small-diameter flexible tube of this embodiment, which is made of FEP resin and has a small tube portion 1a having an inner diameter of 5 μ, a wall thickness of 47.5 μ, and an outer diameter of 100 μ, and a small tube portion 1
It has an inner diameter 10μ, a wall thickness 95μ, and an outer diameter 200μ of a tube large-diameter portion 1b provided at one end of a, and is adhered and fixed by an adhesive agent 11 to a receiver 10 for passing red blood cells through the tube inner hole. There is. A container containing red blood cells is connected to the receiver 10.

In the above-mentioned configuration, an extruding step, a core-removing step, a stretching step, and a receiving member are attached in this order in the order of a small-diameter flexible tube for passage of red blood cells and a manufacturing method thereof, as shown in FIG.
A description will be given based on (e) and FIGS. 3 (a) and 3 (b).

Extrusion Molding Process FIG. 2 (a) shows a coating body 2 having an outer diameter of 200 μ, which is formed by coating the outer periphery of a tungsten wire core 2a having an outer diameter of 10 ± 0.1 μ with the FEP resin 2b by extrusion molding. This extrusion method is basically the same as the FEP resin coated insulated wire,
By increasing the outer diameter accuracy of the tungsten wire,
Increase the inner diameter accuracy of the FEP resin 2b. Where the outer diameter is 200
The reason for setting μ is to stabilize the extrusion capacity in the FEP resin extrusion molding to stabilize the dimensional accuracy of the outer diameter. If the extrusion capacity is stable, the wall thickness (that is, outer diameter) is as small as possible. The thinner one is preferable. The reason why the tungsten wire is used for the core 2a is to prevent the core body 2a from being broken by the tension during extrusion molding, and the material is not particularly limited as long as it has a predetermined tensile strength. Also, the core body 2a
The outer diameter (here, 10 μ) is determined based on the inner diameter of the target small-diameter flexible tube. The extruded cover 2 is cooled and then wound around a winder.

Core removal step The core removal step is a step of removing the core 2a from the above-mentioned coating body 2 to form a flexible tube of FEP resin, and as shown in FIG. 2 (b), the coating is performed. After the body 2 is cut into a length L of about 100 mm, the FEP resin on both ends thereof is peeled off by L ₁ = 10 to 15 mm to expose the core body 2a (FIG. 2 (c)). Next, both ends of the exposed core body 2a are grasped and tensioned to break the wire. Core 2a
The diameter of the disconnection part is reduced by the tension, and the close contact with the covering body 2 at the time of extrusion molding is released ((d) in the same figure). After that, the covering body 2 is cut along the broken line A, and the core body 2a on the right side is extracted ((e) in the figure). Similarly, the core body 2a on the left side is extracted by cutting along the broken line B, and the flexible tube 3 shown in FIG.
(Tube of FEP resin 2b) is formed.

Stretching step The flexible tube 3 made by removing the core 2a from the covering 2 in the core removing step is gripped at one end by hand, and the other end is clamped with a clamp tool such as radio pliers, and stretched by applying tension. Let (second
(Figure (g)). The stretching operation is performed at a temperature below the melting point of the FEP resin 2b,
For example, the heating is performed in an atmosphere of 80 to 100 ° C. FE
Thermoplastics such as P resin have the characteristic of returning to the original shape when heated at a temperature above the drawing process temperature and below the melting point, and in this embodiment, 80% is used in order to guarantee use at room temperature. Stretching is performed in an atmosphere of -100 ° C. It is also for facilitating the stretching operation by heating. Flexible tube 3 with a tube inner diameter of 10μ is 1 /
The stretching amount required to reduce the film thickness to 2 of 5 μ is calculated by the following formula.

ε: Stretch ratio l ₁ : Length of original tube l ₂ : Length after stretching d ₁ : Inner diameter of original tube d ₂ : Inner diameter after stretching Therefore, the stretch ratio when halving the inner diameter of the tube is Four
This stretching is performed within a range that does not break above the yield point of the tube, and when the tube reaches the yield state, it does not deform due to external stress. As shown in FIG. 2 (h), when the stretch ratio reaches a predetermined value, the tube is cut at C and D, leaving the large-diameter portion 1b (unstretched portion of the flexible tube 3) at one end.

Attachment of Receiving Device In this embodiment, as shown in FIG. 3 (a), a tube insertion portion 10a (D ₁ = 190μ) is provided at one end and a large portion for facilitating the inflow of red blood cells at the other end. A receiver 10 made of plastic (for example, fluorine resin) or ceramic having a diameter portion 10b (D ₂ = 1000 μ) was used. After the drawing process, the tube large-diameter portion 1b of the small-diameter flexible tube 1 with both ends cut
As shown in FIG. 3 (b), the tube insertion part 1 of the receiving tool 10
It was engaged with 0a, and the adhesive 11 was applied and fixed.

When the inner diameter and outer diameter of the small diameter flexible tube 1 manufactured as described above were measured using a microscope, the large tube portion 1b had an inner diameter of 10b and an outer diameter of 200μ, and the small tube portion 1a had an inner diameter of 5μ and an outer diameter. With a diameter of 100μ and a wall thickness of 47.5μ, we obtained a small diameter flexible tube of the desired size. Further, as shown in FIG. 4, the small-diameter flexible tube 1 is put into a container 4 filled with the alcohol liquid 4a, and nitrogen gas is put into the container 10 from the end thereof to generate from the tube 1 in the alcohol liquid 4a. Whether or not the tube 1 is damaged can be confirmed by the position of the bubble 4b to be formed.

In the medical small-diameter flexible tube and the method for producing the same of the present embodiment, since the crystalline polymer resin is coated on the core having a small outer diameter by extrusion molding, the dimensional accuracy of the coating is improved, and the core is further improved. Since the resin on the outer circumference of the body is stretched in the longitudinal direction, the inner diameter of the small-diameter flexible tube is stable, and the production is easy. In addition, since one end of the small-diameter flexible tube is made into the original shape and the receiver is fixed to the original shape, inflow of red blood cells is easy. Further, since the small diameter flexible tube is made of FEP resin, it is easy to handle and is not easily damaged. The small-diameter flexible tube of the embodiment is applied to an inspection method for observing the above-mentioned erythrocyte deformity to examine diseases of the blood circulation system such as heart disease, and the erythrocyte deformity viscosity passing through the tube inner diameter and passage. It is possible to directly see the time and the like, data can be easily collected, and variations in the data can be reduced, so that the accuracy of diagnosis can be improved. Furthermore, there is an advantage that a smaller amount of blood is needed for diagnosis, as compared with a test using a plastic thin film (test method of the Heavy Ion Society of West Germany).

〔The invention's effect〕

As described above, according to the medical small-diameter flexible tube of the present invention, since it has an inner hole of several μ having a predetermined accuracy, it is possible to easily diagnose a heart disease or the like by passing red blood cells. According to the manufacturing method, a core having a small outer diameter is coated with a crystalline polymer resin to a predetermined thickness to form a cover, and then the core is removed from the cover. As a result, a flexible tube made of crystalline polymer resin was created, and the flexible tube was stretched in the longitudinal direction to reduce the diameter. It is possible to make a small diameter flexible tube with an applicable inner diameter of a few μ. In addition, since high-precision jigs and tools are not required, it is possible to prevent equipment cost increase.

[Brief description of drawings]

FIG. 1 is a view showing a medical minute diameter flexible tube of this embodiment. 2 (a) to 2 (h) are views for explaining a method for manufacturing a medical-use minute diameter flexible tube. FIGS. 3 (a) and 3 (b) are views for explaining a receiver and mounting of the receiver. FIG. 4 is a diagram for explaining the product inspection of the tube. Explanation of symbols 1 …… Medical small diameter flexible tube 1a …… Tube small diameter portion 1b …… Tube large diameter portion 2 …… Coating body 2a …… Core body 2b …… FEP resin 3 …… Flexible tube 4 …… Container 4a …… Alcohol liquid 4b …… Bubbles 10 …… Receiver 11 …… Adhesive

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takao Ishido 1144 Higashiushigaya, Sowa-cho, Sarushima-gun, Ibaraki Hirakawa Electric Wire Co., Ltd. Ibaraki 1st factory (56) Reference JP-A-63-168564 (JP, A) JP 63-248404 (JP, A) JP 58-83232 (JP, A) Special table 59-501961 (JP, A)

Claims (6)

[Claims] 1. An inner diameter of several μ, which is made of a crystalline polymer resin,
Also, a medical micro-diameter flexible tube having a wall thickness of several tens of μ. 2. The medical small diameter flexible tube according to claim 1, which has a large diameter portion having an inner diameter of at least 10 μ at one end. 3. The medical small-diameter flexible tube according to claim 1 or 2, wherein a receiving member for passing red blood cells through the tube inner hole is provided at the one end. 4. An extrusion molding step of forming a coating body by coating a crystalline polymer resin on a core body having a predetermined outer diameter to a predetermined thickness, and removing the core body from the coating body. , A core removing step of forming a flexible tube of crystalline polymer resin, and a stretching step of reducing the inner diameter to several μ by stretching the flexible tube in the longitudinal direction. A method for producing a medical-use minute diameter flexible tube. 5. The step of removing the core body, after cutting the coating body to a predetermined length, peeling the coating bodies at both ends thereof to expose the core body, and gripping both ends of the exposed core body. The method for producing a medical-use micro-diameter flexible tube according to claim 4, wherein the core body is cut and removed by applying tension to the core body. 6. The method for producing a medical-use minute diameter flexible tube according to claim 4 or 5, wherein the core is a tungsten wire having an outer diameter of 10 ± 0.1 μm.