JPH07303693A - Medical tube - Google Patents

Abstract

PURPOSE:To provide a medical tube with required properties for a high function catheter, i.e., improved inserting performance, for diagnosis and cure. CONSTITUTION:A medical tube is a homogeneous high function monoor multi- layered tube and consists of a part of which stiffness is continuously changed by heat treatment and/or uniform and a non-heat-treated part. The heat-treated part and the non-heat-treated part are composed of a same material and the difference of initial tensile elasticities of the treated and non-treated parts is at least 5% or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical tube and its manufacturing method.

[0002]

2. Description of the Prior Art Tubes used for medical treatment include diagnostic and
What is used by inserting into the body such as a therapeutic catheter
Some are used outside the body, such as blood circuits, infusion / transfusion sets, and blood bag transition tubes.

Originally, a catheter was a device used for discharging and injecting a body fluid or a drug from a body cavity or a tubular organ, but in recent years, its function has advanced, and for example, percutaneous for expanding a narrowed portion of a blood vessel. Balloon catheter for vascular dilatation used in dynamic angioplasty, urinary balloon catheter with temperature sensor that can simultaneously measure urine and bladder temperature, thermodilution catheter used for heart rate measurement, placed in the heart, arterial infusion Intravascular treatment diagnostic catheters for performing therapy and angiography have been applied. Various applications other than the above have been attempted for these catheters, and now they are about to be applied to all organs, body cavities, and tubular organs.

Up to now, a large-scale operation requiring a thoracotomy, a craniotomy, etc. has been required for heart and brain surgery, and recovery after surgery has been the key to success rather than surgery itself. With the above-mentioned technique using a high-performance catheter, there is no need to cut the human body such as thoracotomy, laparotomy, or craniotomy, and diagnosis / treatment with low physical invasiveness has become possible.

Therefore, since it does not require a large-scale operation, it has the following advantages. For example, it is possible to reduce the pain during and after the operation of the patient, early recovery and early return to society after the operation, less physical damage, less mental burden, and less economic burden. Therefore, it is considered that the diagnostic and therapeutic methods using the catheter will be further developed in the future.

A catheter for diagnosis and treatment achieves its purpose by, for example, advancing inside a blood vessel, reaching a target lesion, expanding a stenosis, injecting a drug, and measuring temperature, pressure and the like. To do. Therefore, the basically required function is easy access to the digestive system, circulatory system, respiratory system and other organs. Means for reaching the target site include insertion / running into blood vessels, digestive tracts, lymphatic vessels, respiratory tracts, urethra, and other body cavities or tissues. When inserting and running the catheter into the body, it is required to have followability to the bent portion (trackability) and easy pushing of the catheter (pushability). Further, it is also required to have flexibility that does not damage living tissues. It is considered that trackability depends largely on the flexibility of the catheter, and pushability depends on the rigidity of the catheter. That is, it is desired to achieve both the contradictory properties of hardness and softness that influence the good insertability of the catheter.

Conventionally, a method for putting a catheter having the above characteristics into practical use has been devised.

[0008] For example, in US Pat. No. 4,775,371, a high density polyethylene tube having an inclination in thickness and diameter is covered with a similar low density polyethylene tube so that the catheter shaft is gradually tapered from the distal end side. A method of hardening is disclosed. However, the production of tubes with a gradient in wall thickness and diameter or the coating method by heat shrinkage as described is complicated,
In addition, it is difficult to stabilize the product quality.

Further, in US Pat. No. 4,976,690, it is attempted to make the flexibility of the tip and the rigidity of the base compatible by reducing the thickness of the tip portion of the inner tube shaft or the outer tube shaft of the dilatation catheter. A method of doing so is disclosed. However, such a catheter with a different diameter has a problem in that the manufacturing method is complicated and the rigidity of the shaft greatly changes at the step portion, so that the catheter is easily broken due to stress concentration.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of these problems, and has the properties required for a high-performance diagnostic / therapeutic catheter applied to various body cavities,
That is, the purpose is to improve the insertability. In order to achieve this object, it is effective to make the tube partially rigid or continuously change the rigidity, and the present invention provides a specific manufacturing method thereof and a medical tube manufactured by the manufacturing method. To do.

[0011]

The present invention has the following construction. (1) A single-layered or multi-layered tube made of a homogeneously molded polymer material, in which a heat-treated portion including a portion whose rigidity continuously changes by heat treatment and / or a uniformly stiffened portion, and a non-heat-treated portion The heat-treated part and the non-heat-treated part are made of the same polymer material, and the tensile initial elastic modulus of the heat-treated part and the non-heat-treated part is at least 5%.
A medical tube having the above difference. (2) The polymer material is molded to produce a hollow molded article, and a part of the hollow molded article is heat-treated in an atmosphere at a temperature not lower than the primary crystallization temperature and not higher than the softening point of the polymer material. ). The method for producing the medical tubing according to [4].

That is, in the medical tube of the present invention, a crystalline thermoplastic resin is used as a raw material, the tube is molded by ordinary extrusion molding, injection molding, etc., and a part of the tube is made of the thermoplastic resin used. By heat-treating for a predetermined time in an atmosphere of temperature that is arbitrarily set from the temperature range above the primary crystallization temperature and below the softening point, the resin that constitutes the tube is partially crystallized, and the rigidity of a part of the tube is improved. Can be obtained.

In the present specification, "continuously changing the rigidity" means that the initial tensile modulus of elasticity of the stiffening portion of the tube moves from one end to the other end of the tube.
It means that it becomes low or high continuously.

The raw material used in the present invention is preferably a crystalline thermoplastic resin, specifically, polyethylene, polypropylene, polyvinyl chloride, polybutene, poly 1,2-
Butadiene, poly (4-methylpentene-1), ionomer, polyamide, polyphenylene sulfide, polyester, fluororesin, polyurethane, and thermoplastic elastomer are preferable. It is also possible to use copolymers or polymer blends based on these resins.

According to the present invention, since the rigidity of a tube obtained by ordinary extrusion molding, injection molding or the like is increased by heat treatment, an untreated portion is a portion which retains flexibility which influences trackability. Become. Therefore, it is desirable that the orientation and crystallinity given at the time of molding be limited to the extent that the flexibility required for the intended use of the medical tube to be produced is exhibited. Therefore, cooling at the time of molding is desirable to be rapidly cooled in order to keep the crystallinity low. Further, in the molding, it is possible to mold into any shape such as a single layer, a multilayer or a tube having a plurality of holes, and the shape is not limited to these, and the tube diameter is not limited.

The molded tube is partially heat-treated by passing a core metal through the tube to maintain its shape. The purpose of this is to crystallize the amorphous region of the resin forming the tube in an atmosphere at any temperature above the primary crystallization temperature and below the softening point, and control the crystallinity by the temperature and time of the heat treatment. To do. However, it is not preferable to take the temperature and time so that the tube undergoes a large dimensional change.

To carry out the heat treatment, no special equipment is required, and only the portion to be treated is placed in an oven having a constant temperature. The crystallinity can be controlled by temperature and time.For example, the crystallinity can be set by leaving it in a furnace with a temperature gradient for a certain time, or by putting it in and out of a furnace at a certain temperature at a certain speed. it can. Further, instead of the furnace, a constant temperature bath using water, glycerin, oil or the like as a heat medium can be used.

Further, the present invention can be easily applied to not only a catheter but also a blood circuit used for the above-mentioned hemodialysis, a tube of an infusion / transfusion set, a transfer tube of a blood bag, and the like.

The rigidity of the tube referred to in the present invention is evaluated by the tensile initial elastic modulus obtained in the tube tensile test. The measurement method uses an ordinary tensile tester, the sample tube is fixed between chucks and pulled at a constant speed, the stress-strain curve is recorded, and the initial tensile modulus of elasticity is calculated from the slope of the tangent line at the beginning of the curve. . The heat-treated and stiffened part has different elastic modulus characteristics compared to the non-heat-treated part, so the degree of rigidity can be evaluated, and the tensile initial elastic modulus of the heat-treated part is at least 5% higher than that of the non-heat-treated part. High is desirable.

[0020]

EXAMPLES The present invention will be described in detail below with reference to examples. The embodiment is an example of the present invention, and the invention is not limited thereto.

Example 1 Polypropylene (Hipol F401, manufactured by Mitsui Petrochemical Co., Ltd .; hereinafter referred to as PP) was used as a raw material resin, and IKG (IK G) was used.
Tube formation was carried out by an ordinary method using an MS20-25 extruder manufactured by Co., Ltd. Cooling was performed with water at a die temperature of 235 ° C. The inner diameter of the molded tube is 1.16m
m × outer diameter 1.40 mm, wall thickness 120 μm, and dimensional accuracy was ± 2% or less in outer diameter. In addition, this tube is homogeneously molded and has an initial tensile elastic modulus of 38.2 kg / mm.
It was ² .

A tube cut into a length of 150 cm has a φ
20 cm from the tip through a 0.70 mm SUS core
Put the remaining part in an oven kept at a temperature of 100 ° C.
After holding for a minute and taking out, the tube was cooled to room temperature to obtain a tube having a rigidized portion.

This tube was tested with a tensile tester (Autograph AGS-100A manufactured by Shimadzu Corporation) at a test speed of 1
The tensile initial elastic modulus was obtained by pulling at a rate of mm / min. The results are shown in Table 1. The relative values in the table are the values of the heat-treated part when the initial tensile elastic modulus of the non-heat-treated part is 100%.

Example 2 The same as Example 1 except that a tube was prepared in the same manner as in Example 1 and kept in an oven kept at 100 ° C. for 2 minutes. The results of the tensile initial elastic modulus are shown in Table 1.

Example 3 The same as Example 1 except that a tube was prepared in the same manner as in Example 1 and kept in an oven kept at 100 ° C. for 3 minutes. The results of the tensile initial elastic modulus are shown in Table 1.

Example 4 The same as Example 1 except that a tube was prepared in the same manner as in Example 1 and kept in an oven kept at 100 ° C. for 5 minutes. The results of the tensile initial elastic modulus are shown in Table 1.

[0027]

[Table 1]

(Comparative Example 1) The tube produced in Example 1 was held in an oven kept at 165 ° C for 1 minute by the same method, taken out, and then cooled to room temperature. 165 ° C is
The softening point of PP exceeds 155 ° C. The initial tensile modulus of elasticity of this tube was determined to be 35.7 kg / m
It was m ² . When the heat treatment was performed at a temperature exceeding the softening point of the resin used, the result was that the resin was softened.

(Example 5) The tube produced in Example 1 was cut into a length of 150 cm, and SUS of φ0.70 mm was cut.
The cored metal was passed through, placed in an oven kept at 140 ° C., leaving 20 cm from the tip, and pulled out of the oven at a constant rate of 2 cm per second. After taking out, the tube was cooled to room temperature to obtain a tube whose rigidity continuously changed. The heat-treated portion was cut from the tip side at intervals of 10 cm, and the initial tensile modulus of elasticity of each portion was obtained. It can be said that the rigidity of the heat-treated portion changes continuously.

[0030]

[Table 2]

(Example 6) Adhesive polyolefin resin (Modic H-100F manufactured by Mitsubishi Yuka) was used as a raw material resin, and tube molding was carried out by an ordinary method using an MS20-25 extruder manufactured by IKG. It was Die temperature 2
It cooled by water cooling at 40 degreeC. The dimensions of the molded tube are 0.48mm inner diameter x 0.65mm outer diameter and wall thickness 85μ.
It was m. The tube was homogeneously molded and had an initial tensile elastic modulus of 50.4 kg / mm ² .

A tube cut into a length of 150 cm has a φ
20mm from the tip through a 0.37mm SUS core
The remaining portion was put in an oven kept at a temperature of 100 ° C., kept for 5 minutes, taken out, and then cooled to room temperature to obtain a tube having a rigidized portion. The initial tensile modulus of elasticity of this tube was determined, and the results are shown in Table 3.

Example 7 The same as Example 6 except that a tube was prepared in the same manner as in Example 6 and kept in an oven kept at 120 ° C. for 5 minutes. The initial tensile modulus of elasticity of this tube was determined, and the results are shown in Table 3.

(Example 8) A polyamide elastomer resin (PEBAX7033SA01 manufactured by ATOCHEM) was used as a raw material resin, and tube molding was carried out by an ordinary method using an MS20-25 extruder manufactured by IKG. Cooling was performed with water at a die temperature of 190 ° C. The dimensions of the molded tube were 1.17 mm inside diameter × 1.42 mm outside diameter and 125 μm in wall thickness. The initial tensile modulus of elasticity of this tube was 24.9 kg / mm ² .

This tube was cut into a length of 150 cm, passed through a SUS core bar having a diameter of 0.70 mm, and 20c from the tip.
The part in which m was left was put in an oven kept at a temperature of 120 ° C., held for 1 minute, taken out, and then cooled to room temperature to obtain a tube having a stiffened portion. The initial tensile modulus of elasticity of this tube was determined, and the results are shown in Table 3.

(Comparative Example 2) A tube was prepared in the same manner as in Example 8 and the same as Example 8 except that the tube was kept for 3 minutes in an oven kept at 60 ° C., which was lower than the primary crystallization temperature. The initial tensile modulus of elasticity of this tube was calculated to be 24.9 kg.
/ Mm ² , there was no change from before the heat treatment.

[0037]

[Table 3]

(Example 9) As a raw material resin, polyphenylene sulfide resin (E1880, manufactured by Toray) and adhesive polyolefin resin (Modic P-310H) were used.
MS20-25 manufactured by IKG Co., Ltd.
Two-layer tube molding in which the outer layer was polyphenylene sulfide and the inner layer was adhesive polyolefin was performed using two extruders and a multilayer die. Cooling was performed with water at a die temperature of 280 ° C. The dimension of the molded tube is 0.5
It was 1 mm × intermediate diameter 0.74 mm × outside diameter 0.91 mm. The initial tensile modulus of elasticity of this tube is 138.3 kg /
It was mm ² .

This tube was cut into a length of 70 cm, passed through a SUS core bar of φ0.45 mm, and 20c from the tip.
The part where m was left was put in an oven kept at a temperature of 130 ° C., kept for 60 minutes, taken out, and cooled to room temperature to obtain a catheter having a stiffened portion. When the initial tensile modulus of elasticity of this tube was determined, it was 173.7 kg / mm ² , and the relative value was 126%. The primary crystallization temperature of polyphenyl sulfide was 127 ° C and the softening point was 260 ° C.

[0040]

As described in detail above, according to the present invention,
Because the tube obtained by ordinary extrusion molding / injection molding can be continuously changed in rigidity by heat treatment,
Using a simple device, it is possible to easily and safely improve the property required for a highly functional catheter for diagnosis / treatment, that is, the insertability.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Kaneko 1500 Inoguchi, Nakai-cho, Ashigarakami-gun, Kanagawa Terumo Corporation

Claims (2)

[Claims] 1. A single-layer or multi-layer tube made of a homogeneously molded polymer material, comprising a heat-treated portion having a portion whose rigidity continuously changes by heat treatment and / or a uniformly stiffened portion, and a non-heat-treated portion. Medical tube characterized in that the heat treated portion and the non-heat treated portion are made of the same polymer material, and the tensile initial elastic modulus of the heat treated portion and the non-heat treated portion has a difference of at least 5% or more. . 2. A polymer material is molded to produce a hollow molded article, and a part of the hollow molded article is heat-treated in an atmosphere at a temperature not lower than the primary crystallization temperature of the polymer material and not higher than the softening point. Item 2. A method for producing the medical tube according to Item 1.