JP2007229452A - Medical tube and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin medical tube whose outer diameter is small, having high mechanical characteristics, and having a low frictional resistance on the inner or outer surface, or both inner and outer surfaces of the tube, and its manufacturing method. <P>SOLUTION: This medical tube includes an inner layer which is made of a coiled mold-releasable filament 3, or a braided tube-shaped article, and an outer surface which is coated with a resin layer 2 for an outer layer. At least one of a fluororesin-coated metal wire whose metal surface is coated with a fluororesin, a fluororesin-mixed polyimide resin-coated metal wire which is coated with a fluororesin-mixed polyimide resin, or a fluororesin filament can be used as the mold-releasable filament. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a medical tube suitable for uses such as a catheter and a manufacturing method thereof.

  A medical tube used for a catheter or the like will be described. In recent years, with the advancement of medical technology, instead of conventional open surgery, the treatment method uses a catheter treatment method or a diagnostic imaging device in which a medical instrument such as a catheter is inserted directly into the patient's body cavity. Endoscopic diagnostic methods for observing and diagnosing affected areas are becoming mainstream. Medical tubes are used as the basic tubes of various catheters and endoscopes used in the field of treatment of such new medical technology.

  In the catheter treatment method described above, a catheter is inserted into a diseased site by guiding a guide wire into a blood vessel that is finely and complexly arranged in a human body, and treatment is performed. In such a treatment method, it is necessary to make the catheter reach the affected area quickly and accurately. Therefore, the medical tube used for the catheter has a characteristic that it can be easily pushed into the blood vessel (pushability), and the characteristic that the rotational force operated at the proximal end of the catheter is reliably transmitted to the distal end of the catheter (torque transmission) In addition, many functional characteristics are required in addition to mechanical characteristics required for operation at the time of operation, such as flexibility for preventing blood vessels from being damaged at the tip of the catheter and kink resistance. For example, in order to reduce physical and mental pain and anxiety of patients during treatment, it is also important that the outer diameter of the medical tube is as small as possible, and that the thin lumen (thin thickness) and the lumen are large. It is one of.

  Furthermore, these medical tubes are required to have low friction characteristics on the inner and outer wall surfaces of the tubes in addition to the characteristics such as torque transmission and kink resistance. That is, in the catheter treatment method, the treatment catheter is inserted into a guiding catheter that guides the treatment catheter to the diseased part, and is guided to the diseased part by the guide wire. In such an operation, the outer surface of the therapeutic catheter contacts the inner wall of the guiding catheter, and the inner surface contacts the outer surface of the guide wire. Therefore, development of a medical tube having low frictional properties between the inner surface and the outer surface is desired as a therapeutic catheter.

  In these medical tubes, the friction resistance of the inner and outer surfaces can be reduced by applying multiple extrusion coatings such as polyethylene or polyurethane on the outside of the tube made of fluororesin or silicone resin in advance to reduce the friction on the inner surface of the tube. The structure and the manufacturing method which make a mechanical characteristic compatible are used.

At present, these catheters have many types of materials such as polyurethane, polyethylene, nylon, fluororesin and silicone rubber, and various structures in which these are multilayered (multilayered structures such as inner layer, intermediate layer, outer layer). Things are used. In addition, in order to improve mechanical properties such as kink resistance and torque transmission, a medical tube in which a metal wire is wound around the inner layer tube in a braided or coiled shape and a plastic resin layer is further provided thereon Patent Documents 1 and 2 propose it.
JP 2000-24115 A JP 2000-262625 A

  However, in the conventional method, an inner layer tube having a low frictional resistance is prepared using a fluororesin or the like, and then a metal wire is wound around the outer layer in a braided shape or a coil shape as a mechanical reinforcing layer. In addition, it is difficult to produce a tube with a small diameter and a thin wall with a large lumen, or to reduce the friction of the inner surface of the tube by an inexpensive method. There is a problem. In addition, thin tubes with large lumens tend to bend and collapse, and medical tubes that satisfy the above-mentioned required characteristics such as pushability and torque transmission properties have not yet been developed. Absent.

  Therefore, the present invention solves these problems, and provides a medical tube having a small outer diameter, a thin wall, high mechanical properties, and a low frictional resistance on the inner surface, outer surface, or inner and outer surfaces of the tube, and a method for manufacturing the medical tube. For the purpose.

  The present inventors use a releasable filament as a starting material to reduce the friction on the inner surface of the tube, and the releasable filament is directly wound or braided into a coil shape to form a tubular shape. By forming the molded structure, it was found that the reinforcing force of the tube can be increased and the above problems can be solved, and the present invention has been completed.

  That is, the medical tube of the present invention is a medical tube composed of at least two layers of an inner layer and an outer layer, and the inner layer of the medical tube is a tube-shaped object in which a releasable filament is rotated in a coil shape, or a separation member. It has a structure in which the outer surface of the inner layer is covered with a resin layer for an outer layer.

  The releasable filament is at least selected from a fluororesin-coated metal wire coated with a fluororesin on the surface of a metal wire, a fluororesin mixed polyimide resin-coated metal wire coated with a fluororesin mixed polyimide resin, and a fluororesin filament. It is one releasable filament.

  Next, the resin layer for the outer layer is a fluororesin or a fluororesin mixed polyimide resin, and is fused to the inner layer of the tubular body.

  Next, in the method for producing a medical tube according to the present invention, a tube-shaped body is manufactured by rotating or braiding a releasable filament in a coil shape on the surface of a core body made of a continuous metal wire. The outer surface of the tube-shaped body is coated with an outer resin layer to produce a medical tube intermediate product, and then the medical tube intermediate product and the core are separated.

  According to the medical tube of the present invention, a release resin filament of any one of a fluororesin-coated metal wire coated with a fluororesin, a fluororesin mixed polyimide resin-coated metal wire coated with a fluororesin mixed polyimide resin, or a fluororesin filament Since the inner layer of the structure formed into a tubular shape has the low friction characteristics of the fluororesin, the structure of the coiled or braided braid increases the mechanical reinforcement. Since it plays a role at the same time, even if it is thin, there is no occurrence of bending or crushing, and it has high mechanical properties. Furthermore, since the inner surface of the medical tube of the present invention is formed in a coil shape or a braided shape by a releasable filament, there are moderate irregularities on the inner surface of the tube, and it comes into contact with insertion of a guide wire or the like. It has a small area, combined with the low friction property of the fluororesin and the concave and convex shape, and the guide wire can be smoothly put in and out. Furthermore, since the inner surface of the inner layer is fluororesin, it is chemically stable and has a thrombus. Occurrence can also be prevented.

  Next, an embodiment of the present invention will be described. FIG. 1 is a schematic cross-sectional view showing an example of the medical tube of the present invention. FIG. 1 shows that a fluororesin-coated metal wire 1 is used as a releasable filament, and has an inner layer of a tube-shaped body that is closely wound by contacting a fluororesin-coated metal wire in a coil shape without any gap, and an outer layer on the outer surface This is a medical tube having a structure in which the fluororesin layer 2 is coated and fused as a resin layer. Reference numeral 3 is a metal wire, and 4 is a fluororesin layer covering the metal wire.

  In the medical tube of the present invention, the inner layer of the medical tube is composed of a tube-shaped body obtained by rotating a releasable filament in a coil shape, or a tube-shaped body formed by braiding a releasable filament, and the outer surface of the inner layer is It is a structure coated with an outer resin layer. The structure of the tube-shaped body described above plays a role to obtain pushability or torque transmission as a medical tube, and even if it is thin, there is no occurrence of bending or crushing, and excellent mechanical properties Is obtained. Further, the inner surface of the inner layer has a concavo-convex shape, combined with the low friction property of the fluororesin itself and the concavo-convex shape, has a low frictional resistance, and is excellent in operability for insertion and extraction of a guide wire and the like.

  In the present invention, the releasable filament is selected from a fluororesin-coated metal wire in which a metal wire is coated with a fluororesin, a fluororesin mixed polyimide resin-coated metal wire in which a fluororesin mixed polyimide resin is coated, and a fluororesin filament. Any one is preferred. More preferably, a fluororesin-coated metal wire and a fluororesin mixed polyimide resin-coated metal wire are used as the releasable filament. This is because each of the coated metal wires can produce a thin tube by using a thin wire diameter, and an improvement in mechanical characteristics against bending and crushing can be easily obtained.

  Next, the metal wire used for the releasable filament is preferably stainless steel, titanium, iron, tungsten, boron, nickel, piano wire, or various alloy wires. The wire diameter of the metal wire is preferably 10 μm to 1000 μm, and more preferably 30 μm to 500 μm. The metal wire is preferably a metal wire having a shape such as a round wire, a half-round wire, and a flat wire. This is because when it is turned into a coil shape, characteristics such as kink resistance and crushing by pressing force can be improved.

  The fluororesin used for the fluororesin-coated metal wire is tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene hexafluoropropylene copolymer (FEP), tetrafluoroethylene (PTFE), polychlorotrifluoroethylene. (PCTFE), tetrafluoroethylene-ethylene copolymer (PETFE), polyvinylidene fluoride (PVDF), and the like. These fluororesins can be used alone or in combination. PFA, FEP, and PTFE are the most preferred materials because of their chemical stability and low frictional properties.

  The thickness of the fluororesin layer of the fluororesin-coated metal wire is preferably in the range of 5 μm to 200 μm, and more preferably in the range of 10 μm to 100 μm. Within this range, scratches and the like are not generated even when the coil is turned, and handling is easy, and when formed into a tube-shaped body, low friction characteristics and durability can be obtained.

  Next, another preferable releasable filament in the present invention is a fluororesin mixed polyimide resin-coated wire obtained by imidizing after applying to a metal wire using a mixed solution in which a fluororesin powder is mixed with a polyimide precursor solution. It is to use a metal wire. The present inventors have already proposed a medical tube made of a fluororesin and a polyimide resin in Japanese Patent Publication No. 2005-205183 for improving the slidability of the inner and outer surfaces of the medical tube. The medical tube proposed in the above publication is a medical tube obtained by imidizing by heating after being molded into a tube shape using a mixture of a fluororesin and a polyimide precursor solution, and in the polyimide precursor solution The mixed fluororesin is melted and deposited on the surface of the tube by completing imidization at a temperature equal to or higher than the melting point of the fluororesin, and the inner surface or inner / outer surface of the tube has a low friction characteristic of fluororesin. It is related with the tube.

  As disclosed in the above patent, the fluororesin powder is mixed with the polyimide precursor solution, molded into a tube, and heated to complete imidization, the fluororesin melts on the tube surface or the front and back surfaces. It has been found that characteristics such as releasability, water repellency, and low friction properties of the fluororesin can be obtained. In the present invention, the fluororesin mixed polyimide precursor solution is applied to a metal wire and heated to complete imidization, so that the fluororesin melts and precipitates on the surface of the fluororesin mixed polyimide resin-coated metal wire. Thus, a releasable filament having excellent releasability and low friction can be obtained. Next, by rotating or braiding the releasable filament into a coil shape and forming it into a tube-shaped body, it is possible to satisfy the thinning of the tube and the mechanical characteristics at the same time. Can be provided.

  The thickness of the coating layer of the fluororesin mixed polyimide resin-coated metal wire is preferably in the range of 5 to 100 μm. This is because even if the polyimide resin coating is thin, sufficient mechanical properties can be obtained, and a thin medical tube having a large lumen can be obtained by reducing the thickness of the coating layer.

  Further, in the present invention, it is preferable to use a filament made of a fluororesin alone as a releasable filament, rotate or braid it into a coil shape, shape it into a tube-shaped object, and use it as an inner layer. As the filament made of a single fluororesin, it is preferable to use one obtained by melt extrusion molding PFA, FEP, PCTFE, PETFE, PVDF or the like.

  The outer diameter of the fluororesin filament is preferably 30 μm to 1000 μm, more preferably 50 μm to 700 μm. When the outer diameter is 30 μm or less, it does not substantially act as a reinforcing material, and when the outer diameter is 1000 μm or more, the thickness of the tube increases.

  Next, in the present invention, the structure of the tube-shaped object obtained by rotating in a coil shape using a releasable filament is a structure in which the releasable filaments are closely contacted with each other without any gaps and closely wound in a coil shape. If it exists, deformation such as crushing due to kink resistance or pressing can be solved, which is preferable. After the releasable filaments are formed in a coil shape by tightly swirling without any gaps, the releasable filaments are fused together by heat treatment, and the tube-like shape is maintained, and flexibility and chemical stability are maintained. A tube having the characteristics described above can be produced.

  Further, the structure in which the releasable filament is rotated into a coil shape and formed into a tube-shaped body has a portion that is closely coiled as described above and a portion that is spirally rotated at a predetermined pitch. The structure is preferable because a spirally wound portion is used for the distal end portion of the medical tube, and flexibility for preventing the blood vessel from being damaged at the distal end of the catheter can be imparted.

  Next, in this invention, it is preferable that the resin layer for outer layers is a fluororesin or a fluororesin mixed polyimide resin, and is fuse | melted with the inner layer of the tubular-shaped body. The inner layer formed into a tubular shape with a fluororesin-coated metal wire, a fluororesin mixed polyimide resin-coated metal wire, or a fluororesin filament is flexible but easily deformed as it is, and its outer surface is fluororesin, or This is because the mechanical characteristics can be further improved if the shape is covered with a resin layer for an outer layer of a fluororesin mixed polyimide resin.

The fluororesin used as the outer resin layer is not particularly limited, and PFA, FEP, PTFE, PCTFE, PETFE, PVDF, or the like can be used alone or in combination.

  In this invention, when using a fluororesin as a resin layer for outer layers, the range whose thickness is 10-300 micrometers is preferable, and the range which is 30-100 micrometers is more preferable. This is because within this range, sufficient flexibility, kink resistance and mechanical properties can be obtained as a medical tube.

  Next, the fluororesin mixed polyimide resin used as the outer resin layer can be used as it is as the coating material for the fluororesin mixed polyimide resin-coated metal wire. Moreover, according to the required characteristic of a medical tube, the kind and mixing amount of fluororesin powder can be changed, and it can also use individually as a coating layer of a covered wire, or the resin layer for outer layers. In the present invention, the fluororesin powder to be mixed with the polyimide precursor solution may be a single powder or a mixture of powders such as PTFE, PFA, FEP, CPTFE. PTFE, PFA, and FEP are preferable materials because they are excellent in heat resistance and releasability, and are chemically inert. The mixing amount of the fluororesin powder is preferably in the range of 3 to 50% by mass with respect to the solid content of the polyimide precursor solution. Especially preferably, it is the range of 10-40 mass%.

  The average particle size of the fluororesin powder is preferably in the range of 0.1 to 25 μm. More preferably, it is the range of 1.0-15 micrometers. This is because within such a range, the fluororesin powder is less aggregated and can be uniformly dispersed.

  In addition, the coating layer of the fluororesin mixed polyimide resin-coated metal wire or the resin layer for the fluororesin mixed polyimide outer layer can use a polyimide precursor solution as a starting material, and the polyimide precursor solution is an aromatic tetracarboxylic acid. It can be obtained by reacting approximately equimolar amounts of dianhydride and aromatic diamine in an organic polar solvent.

  Representative examples of the aromatic tetracarboxylic dianhydride include 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, pyromellitic dianhydride, 2,3,3 ′, 4- Biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8- Naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 2,2′-bis (3,4-dicarboxyphenyl) propane dianhydride, perylene-3,4, 9,10-tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, and the like.

  Representative examples of the aromatic diamine include 4,4'-diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, 1,5-diaminonaphthalene, 3,3'-dichlorobenzidine, 3,3'- Diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 3,3′-dimethyl-4,4′-biphenyldiamine, 4,4′-diaminodiphenyl sulfide-3,3′-diaminodiphenylsulfone, benzidine, 3,3 ′ -Dimethylbenzidine, 4,4'-diaminophenylsulfone, 4,4'-diaminodiphenylpropane, m-xylylenediamine, hexamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine and the like.

  These aromatic tetracarboxylic dianhydrides and aromatic diamines can be used alone or in combination. It is also possible to complete the polyimide precursor solution and use the precursors mixed.

  Examples of the organic polar solvent for reacting the aromatic tetracarboxylic dianhydride and the aromatic diamine include N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide, N, N-dimethylacetamide, N, N -Diethylformamide, N, N-diethylacetamide, dimethyl sulfoxide, hexamethylphosphortriamide, dimethyltetramethylene sulfone, ethylene carbonate, propylene carbonate, γ-butyrolactone and the like. These organic polar solvents can be used alone or in combination.

  The polyimide precursor solution is obtained by reacting the aromatic tetracarboxylic dianhydride and the aromatic diamine in an organic polar solvent usually at 90 ° C. or less, and the solid content concentration in the solvent is: Although it can be set according to the specifications and processing conditions of the medical tube, it is 10 to 30% by mass.

  In addition, when aromatic tetracarboxylic dianhydride and aromatic diamine are reacted in an organic polar solvent, the viscosity of the solution increases depending on the polymerization conditions. Can do. It is usually used at a viscosity of 1 to 5000 poise depending on manufacturing conditions and working conditions.

  Also, in order to deposit the fluororesin on the outer surface of the fluororesin mixed polyimide resin-coated metal wire or the resin layer for the fluororesin mixed polyimide outer layer, the temperature exceeding the melting point of the fluororesin mixed in the polyimide precursor solution Need to be imidized. The maximum temperature for the imidation treatment is preferably 10 minutes C or more higher than the melting point of the mixed fluororesin and the imidization is completed within 30 minutes. If it is longer than 30 minutes, the thermal decomposition of the fluororesin and the mechanical properties of the polyimide may be lowered, which is not preferable.

  Next, in the present invention, plastics such as polyurethane, nylon, polyethylene, polypropylene, polyvinyl chloride, silicone rubber, polyester and the like are further provided on the outer surface of the outer resin layer made of fluororesin or fluororesin mixed polyimide resin. It is preferable to add characteristics such as flexibility and handling operability by covering the material. Further, depending on the required characteristics of the medical tube, the plastic material can be directly coated on a tubular shape obtained by rotating or braiding a releasable filament in a coil shape. This is because medical devices such as catheters require many types of catheters having different characteristics depending on the diseased part and the content of treatment, and can meet the demands for flexibility and cost reduction.

  The medical tube of the present invention can be manufactured by the following method as an example. A tube-shaped object is obtained by rotating a pre-fabricated fluororesin-coated metal wire in a coil shape without gaps on the surface of a long metal wire having a predetermined outer diameter (a diameter corresponding to the inner diameter of the tube). Is molded. After that, the molded product is immersed in a fluororesin dispersion and applied to a predetermined thickness to form an outer resin layer. At the same time as the outer resin layer is fired, it is fused and integrated with the inner fluororesin coating layer. To produce a long medical tube intermediate product. Thereafter, the intermediate medical tube intermediate product is cut into a predetermined length, and both ends of the core body are gripped and stretched to reduce the outer diameter, thereby obtaining the medical tube of the present invention. The medical tube of the present invention has an inner surface made of a fluororesin and has fine irregularities such as a coil shape or a braid shape, so that the medical tube can be easily pulled out without damaging the medical tube. Out.

  In the manufacturing method of the present invention, a stainless steel wire, a silver plated copper wire, or the like can be used as the core. Since the core is disposable, it is preferably an inexpensive metal wire.

  Next, the fluororesin-coated metal wire used as the releasable filament can be produced by a melt extrusion coating method, an electrostatic powder coating method, or a method of coating and firing a fluororesin dispersion. In the present invention, if necessary, a primer is applied to the surface of the metal wire, and after drying, a dispersion (dispersion or enamel solution) such as PTFE, PFA, FEP is applied to a predetermined thickness, and then the fluororesin is baked. The manufacturing method is preferable. This is because this method makes it possible to coat the fluororesin thinly and uniformly, and to easily cope with changes in the cross-sectional shape of the metal wire.

  Next, the manufacturing method of the fluororesin mixed polyimide resin-coated metal wire is to immerse the metal wire in a mixed solution in which the fluororesin powder is mixed in advance with the polyimide precursor solution, and to mold to a certain thickness using a die with a predetermined inner diameter After that, imidization can be completed by drying and heating. In order to deposit the fluororesin on the outer surface of the fluororesin mixed polyimide resin-coated metal wire, it is an essential condition that the temperature at which the imidization is completed is heated to a temperature higher than the melting point of the fluororesin. .

  Next, a method of winding or braiding a releasable filament such as a fluororesin-coated metal wire or a fluororesin mixed polyimide resin-coated metal wire into a coil shape is a coiling machine, a horizontal winding shield machine, a blade machine, a braiding machine by a regular method. It can produce using.

  Next, the outer layer resin layer can be molded by a melt extrusion method or the like when a thermoplastic material such as PFA, FEP, polyethylene, or nylon is used as the outer layer resin. In the present invention, it is preferable to use a liquid raw material such as a fluororesin dispersion or a fluororesin mixed polyimide precursor, coat by immersion, and then heat calcinate or complete imidization. With this method, it can be molded in a state where a liquid raw material is impregnated into a minute uneven portion of a tube-shaped body formed by coiling or braiding, and the inner layer and the outer resin layer are integrated and firmly This is because it can be fused. In addition, as shown in Fig. 2, the outer resin layer is molded with a structure that wraps the tube-shaped product even when a fluororesin-coated metal wire is spirally wound around the core at a predetermined pitch. This is because a flexible medical tube can be produced.

Next, when manufacturing a medical tube using a fluororesin mixed polyimide precursor as a metal wire coating layer and an outer resin layer, first, an imide in the step of preparing a fluororesin mixed polyimide coated metal wire The coated wire is produced by performing the treatment at a temperature lower than the melting point of the fluororesin. Subsequently, the coated metal wire is rotated in a coil shape on the core, and a fluororesin mixed polyimide precursor solution is applied to the surface as a resin layer for the outer layer. Thereafter, a method in which the coating layer and the outer layer are fused by heating to the melting point or higher of the fluororesin is preferable. When producing a fluororesin mixed polyimide resin-coated metal wire, if imidization proceeds at a temperature lower than the melting point of the fluororesin, no fluororesin is deposited on the surface of the coated metal wire, and an outer layer resin layer is formed on the outer surface. This is because it is easy to mold the fluororesin mixed polyimide precursor solution.
(Example)

  Hereinafter, the present invention will be described in more detail based on examples. Moreover, the dynamic friction resistance value of the medical tube inner surface obtained by the present invention was measured by the following method. As shown in FIG. 3, a nylon wire (product name “Gunter 4” manufactured by Unitika Ltd.) 51 having a wire diameter of 0.33 mm and a length of 1100 mm is previously inserted into a medical tube 52 having a length of 900 mm, and a tube having a diameter of 67 mm. The tube is wound around the support 53 four times, and both ends of the tube are vertically held, fixed with adhesive tape, and this support is attached to a fixed chuck 57 of a tensile tester. Thereafter, one end of the nylon wire 51 is fixed to the clip 54 of the tensile testing machine 55, pulled in the direction of the arrow 56 at a speed of 200 mm per minute, and the load at this time is measured, whereby a medical tube is obtained. The frictional resistance value between the inner wall and the nylon wire outer surface was measured. The smaller the tensile load, the smaller the frictional resistance. In the measurement, the value of the tensile load was recorded on a chart over a distance of 100 mm between the tensile distances, and the average value of three tests was calculated from the data.

(1) Preparation of fluororesin-coated metal wire A stainless steel wire having a diameter of 0.05 mm was prepared, immersed in a primer (“855-300” manufactured by DuPont Co., Ltd.), dried at 150 ° C., and about 2 μm in diameter. A primer-coated wire coated to a thickness was prepared. Subsequently, the primer coat wire is dipped in PTFE dispersion (“855-510” manufactured by DuPont), dried at 150 ° C., fired at 380 ° C., and coated with PTFE to a thickness of 20 μm. A fluororesin-coated metal wire was prepared and wound.

(2) Preparation of coiled inner layer tube-shaped body (A) A stainless steel wire having an outer diameter of 0.5 mm is used as the core, and the fluororesin-coated metal wire produced in the step (1) is placed on the stainless steel wire. A tube-shaped body (A) (a tube-shaped body rotated in a coil shape on a core body) with a fluororesin-coated metal wire was produced by densely winding in a coil shape without a gap.

(3) Molding of resin layer for outer layer The tubular shaped product (A) is immersed in the PTFE dispersion (“855-510” manufactured by DuPont Co., Ltd.) used in the item (1), and is 150 to 270 degrees. Drying was performed at a temperature of C, and immersion and drying were repeated 5 times, and thereafter, a medical tube intermediate product (A ′) in which a resin layer for an outer layer was formed by baking at 380 ° C. was produced. The thickness of the outer resin layer was 50 μm. Thereafter, the medical tube intermediate product (A ′) is cut to a length of 2 m, the outer layer resin layer and the inner layer at both ends are peeled off by about 20 mm to expose the core, and both ends are pulled to reduce the diameter. Was extracted to obtain a medical tube. The resulting medical tube has an inner diameter of 0.5 mm, a total thickness of approximately 145 μm, is thin, and is reinforced with a fluororesin-coated metal wire that has a coiled structure to produce a medical tube that is resistant to bending and pressing. did it. Further, when the frictional resistance value of the inner surface is measured, it is 0.15N, which is 1/2 of the frictional resistance value (0.3N) of the PTFE single tube of the same diameter, and has a low friction characteristic. A tube could be obtained.

(1) Preparation of fluororesin mixed polyimide precursor solution PyrML “RC5063” manufactured by IST was used as a polyimide precursor solution. This precursor solution was biphenyltetracarboxylic acid as an aromatic tetracarboxylic dianhydride. Polymerized in N-methyl-2-pyrrolidone “NMP” using dianhydride “BPDA” and paraphenylenediamine “PPD” as an aromatic diamine, the solid content was 17.5%. PTFE powder having an average particle size of 3.0 μm (melting point: 327 degrees C: trade name “Zonyl MP1100” manufactured by DuPont) in the precursor solution is in a proportion of 28 parts by mass with respect to 100 parts by mass of the solid content of the polyimide precursor solution. The mixture was stirred and dispersed uniformly, and then a coarse foreign material was filtered using a 250 mesh stainless steel wire mesh. As a result, a rotational viscosity of the polyimide precursor solution was 100 poise, which was measured with a B-type viscometer at a temperature of 23 degrees C.

(2) Preparation of fluororesin mixed polyimide resin-coated metal wire A stainless steel wire having a diameter of 0.05 mm is prepared, immersed in the fluororesin mixed polyimide precursor solution, and the thickness of the precursor solution is reduced to about 5 μm through a die. The film was dried at a temperature of 150 ° C. to 250 ° C., and coating and drying were repeated continuously to form a thickness after semi-curing of the fluororesin mixed polyimide resin film to 7 μm. The fluororesin mixed polyimide resin-coated metal wire surface is a fluororesin mixed polyimide semi-cured metal wire in which no fluororesin is deposited and the polyimide resin is coated with a semi-cured coating.

(3) Production of tube-shaped body (B) rotated in a coil shape Using a stainless steel wire with an outer diameter of 1.25 mm as the core, the fluororesin mixed polyimide semi-cured coated wire produced in the above process is tightly rotated without gaps. Thus, a tube-shaped object (B) (a tube-shaped object rotated in a coil shape on the core body) was produced.

(4) Production of resin layer for outer layer The tubular shaped product (B) is dipped again in the fluororesin mixed polyimide precursor solution prepared in the section (1) of this example, and is applied through a die. Drying was performed at a temperature of 250 ° C., application and drying were repeated, and then imidization was completed at 380 to 400 ° C. to produce a medical tube intermediate product (B ′). The thickness of the outer resin layer was 30 μm. Thereafter, the medical tube intermediate product (B ′) was cut to a length of 2 m, the core body was reduced in diameter, and extracted to prepare a medical tube. The obtained medical tube has an inner diameter of 1.25 mm, a total thickness of about 95 μm, and is thin. PTFE resin melts and precipitates on the surface of the outer resin layer and the inner surface of the inner layer obtained from the fluororesin mixed polyimide resin. In addition, a medical tube having release properties, water repellency, and low frictional properties possessed by the fluororesin and strong against bending and pressing could be produced. Moreover, when the frictional resistance value of the inner surface was measured, it was 0.22N, and a medical tube having a low frictional resistance could be produced.

  A tube-shaped body (C) in which 16 pieces of fluororesin-coated metal wires produced in Example 1 were braided and knitted was used, using a silver-plated copper wire having an outer diameter of 1.50 mm as a core. Thereafter, a resin layer for outer layer made of PTFE was formed in the same manner as in Example 1 to produce a medical tube intermediate product (C ′), and then separated from the core to produce a medical tube. The obtained medical tube had an inner diameter of 1.5 mm, a total thickness of 220 μm, was thin, was reinforced with a braided fluororesin-coated wire, and a medical tube resistant to bending and pressing could be produced. Further, when the friction resistance value of the inner surface was measured, it was 0.19 N, and a medical tube having a low friction resistance in which the inner and outer surfaces of the tube were formed of a fluororesin layer could be obtained.

(1) Production of tube-shaped body (D) with PFA filament Using a PFA filament with a fiber diameter of 75 μm as a releasable filament, the filament is tightly packed on the surface of a stainless steel wire with an outer diameter of 0.75 mm as a core. A tube-like feature (D) (tube-like feature rotated in a coil shape) was produced by a PFA filament rotated in a coil shape.

(2) Production of resin layer for outer layer The tubular shaped product (D) made of the PFA filament is immersed in a PFA dispersion (trade name PFA920HP plus “ENA-162-8” manufactured by DuPont), and has a temperature of 150 to 250 ° C. Drying was performed at a temperature, dipping and drying were repeated 5 times, followed by firing at a temperature of 330 ° C. to produce a medical tube intermediate product (D ′), and the thickness of the outer resin layer was 70 μm. The medical tube intermediate product (D ′) is cut to a length of 2 m, the outer resin layer and the inner layer at both ends are peeled off by about 20 mm to expose the core, and both ends of the core are pulled to reduce the diameter. The medical tube was pulled out to obtain a medical tube with an inner diameter of 0.75 mm and a thin film thickness of 145 μm, and it was turned into a coil and reinforced with a PFA filament. A medical tube resistant to bending and pressing could be produced, and the frictional resistance value of the inner surface was measured to be 0.16 N, and a medical tube having a low frictional resistance could be obtained.

  In Example 2, when the outer layer resin layer was produced, the polyimide precursor solution of the fluororesin mixed polyimide precursor was changed to PyrML “RC5019” manufactured by IST, and the thickness of the outer layer resin layer was molded to 30 μm. A medical tube was produced under the same conditions as in Example 2 except that. The “RC5019” precursor solution was obtained by polymerizing pyromellitic dianhydride “PMDA” and 4,4′-diaminodiphenyl ether “ODA” as aromatic tetracarboxylic dianhydrides in NMP. It was 17.5%. The obtained medical tube has an inner diameter of 1.25 mm and a total thickness of about 95 μm and is thin. PTFE resin melts and precipitates on the surface of the outer resin layer obtained from the fluororesin mixed polyimide resin, and the fluororesin Thus, a medical tube having releasability, water repellency, and low frictional characteristics possessed by bending and pressing can be produced. Moreover, when the frictional resistance value of the inner surface was measured, it was 0.15 N, and a medical tube having a low frictional resistance could be obtained. In addition, this medical tube was superior in kink resistance and flexibility to the medical tube produced in Example 2 because the polyimide resin used for the outer resin layer had flexible characteristics.

  Using the tubular structure (A) using the fluororesin-coated metal wire prepared in Example 1, this tubular structure (A) was passed through a 350 ° C. tunnel furnace and heat-treated to form a coil. Each coating layer of the fluororesin-coated metal wire that was tightly rotated without a gap was fused. Thereafter, a room temperature curable urethane resin (Nippon Polyurethane Co., Ltd.) was molded to a thickness of 70 μm by die molding as an outer resin layer, heat treated at a temperature of 100 ° C. to sufficiently accelerate the curing reaction, and then the core was A medical tube was obtained in which the extracted inner layer was made of a tube-shaped body of a fluororesin-coated metal wire and the outer layer was coated with polyurethane. The total thickness of the obtained medical tube is about 165 μm, which is 0.12 N as a result of measuring the friction resistance value of the inner surface, which is thinner than that of a general catheter tube. A medical tube with excellent properties could be produced.

  The medical tube of the present invention can be suitably used as a tube serving as a backbone of a catheter, an endoscope or the like.

FIG. 3 is a schematic cross-sectional view of a medical tube having a structure in which the fluororesin-coated metal wire of Example 1 is densely rotated without a gap. FIG. 2 is a schematic cross-sectional view of a medical tube having a structure in which a fluororesin-coated metal wire is spirally rotated at a predetermined pitch in the medical tube of the present invention. It is the schematic which shows the measuring method of the dynamic friction resistance of the medical tube inner surface of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fluororesin-coated metal wire 2 Resin layer for outer layer 3 Metal wire 4 Metal wire coating layer 50 Dynamic friction resistance measuring device

Claims (4)

  A medical tube comprising at least two layers of an inner layer and an outer layer, wherein the inner layer is formed of a tube-shaped body obtained by rotating a releasable filament in a coil shape, or a tube-shaped body formed by braiding a releasable filament; A medical tube having a structure in which an outer surface of the inner layer is covered with an outer resin layer.   The releasable filament is at least one selected from a fluororesin-coated metal wire whose surface is coated with a fluororesin, a fluororesin mixed polyimide resin-coated metal wire coated with a fluororesin mixed polyimide resin, and a fluororesin filament. The medical tube according to claim 1, wherein the medical tube is a releasable filament.   2. The medical tube according to claim 1, wherein the outer resin layer is a fluororesin or a fluororesin mixed polyimide resin and is fused to the inner layer of the tubular body.   A tube-shaped body is produced by rotating or braiding a releasable filament in the shape of a coil on the surface of a core composed of continuous metal wires, and then coating the outer surface of the tube-shaped body with an outer resin layer. Then, a medical tube intermediate product is produced, and then the medical tube intermediate product and the core are separated from each other.

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