JP2014100331A - Catheter tube manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catheter tube manufacturing method capable of efficiently and effectively setting a rigidity of a plurality of catheter tubes while continuously manufacturing the catheter tubes using the same core wire.SOLUTION: A catheter tube manufacturing method comprises: a coat body forming step of forming a coat body 50 by applying a coat of a resign onto a core wire 40; a hardness change processing step of applying a hardness change processing to the coat body 50; a cutting step, following the hardness change processing step, of cutting at predetermined positions a tubular continuous body 60 obtained by forming the core body 50 on the core wire 40, into a plurality of discrete tubes 61; and a core wire removing step of removing the core wire 40 from the discrete tubes 61.

Description

  The present invention relates to a method for manufacturing a catheter tube used for a catheter used in a lumen such as a blood vessel or a body cavity.

  In recent years, treatment in a lumen such as a blood vessel or a body cavity using a catheter has been actively performed for the reason that surgical invasion is very low. For example, a catheter that is selectively introduced into a complicatedly branched blood vessel in the body is generally pushed selectively along a guide wire that is introduced into the blood vessel in advance, and is used for therapeutic drugs or diagnostics. The contrast medium or the like is circulated from the proximal side (base end side) to the distal end side. For this reason, the long catheter tube that constitutes the catheter increases the inner and outer diameters on the proximal end side, thereby increasing the rigidity and providing sufficient pushability. By securing the characteristics and making the inner and outer diameters on the distal end side thinner than the proximal end side and making it flexible, the reachability to the peripheral blood vessels and the followability to the guide wire are enhanced.

  As a method for manufacturing such a catheter tube, for example, Patent Document 1 discloses that a covering is formed by coating a thermoplastic resin on a core wire in which a large diameter portion and a small diameter portion are continuous at a predetermined interval. A method is described in which a plurality of catheter tubes are formed as a continuous body on the same core wire, then the continuous body is cut together with the core wire for each catheter tube, and the core wire is pulled out and removed to obtain a catheter tube. ing.

JP 2008-183226 A

  However, in the method described in Patent Document 1 described above, the rigidity on the distal end side and the proximal end side is changed by changing the outer diameter and the inner diameter on the distal end side and the proximal end side of the catheter tube. The rigidity depends on the outer diameter and inner diameter applicable to the tube, and the rigidity applicable to the catheter tube is limited.

  The present invention has been made in order to solve the above-described problems, and is capable of efficiently and effectively improving the rigidity of a manufactured catheter tube while continuously manufacturing a plurality of catheter tubes using the same core wire. An object of the present invention is to provide a method for manufacturing a catheter tube that can be set in an objective manner.

  A method of manufacturing a catheter tube that achieves the above-described object includes a covering body forming step of coating a resin on a core wire to form a covering body, a hardness changing treatment step of performing a process of changing the hardness of the covering body, A cutting step of cutting a tubular continuous body obtained by providing the covering on the core wire after a hardness change treatment step at a predetermined position to cut out a plurality of single tubes, and a core wire for removing the core wires from the single tube And a removing step.

  The method of manufacturing a catheter tube configured as described above includes: coating a core on a core wire; subjecting the cover to a change in hardness; and cutting the tubular continuous body at a predetermined position to form a plurality of single units Since the tube is cut out, it is not necessary to re-position the single tube cut out to form the hardness change process after cutting, and the number of times of positioning for performing the work can be reduced, and a plurality of catheter tubes can be made the same. Stiffness can be set efficiently and effectively while manufacturing continuously using a core wire.

  If the treatment for changing the hardness includes at least one of a curing treatment for increasing the hardness by crosslinking the material by irradiation with an electron beam or gamma rays, and a softening treatment for reducing the hardness using an acid or alkali, The hardness of the coating can be freely changed by the curing process or the softening process.

  If the core wire is formed such that a large-diameter portion and a small-diameter portion having different outer diameters are continuously formed in advance at predetermined intervals, catheter tubes having different diameters at the distal end portion and the proximal end portion are continuously formed. It can manufacture efficiently using a continuous tubular continuous body.

  In the hardness change treatment step, if a hardening treatment for increasing the hardness is performed on the portion corresponding to the large diameter portion of the covering, the hardness of the proximal end side of the manufactured catheter tube is increased and the pushability is increased. In addition, kink resistance can be improved.

  In the hardness change processing step, if a softening process for reducing the hardness is performed on the portion corresponding to the small diameter portion of the covering, the hardness on the distal end side of the manufactured catheter tube is reduced, It is possible to improve reachability to blood vessels and the like and followability to guide wires.

  The covering includes an inner layer covering that is coated on a core wire and an outer layer covering that is coated on a radially outer side of the inner layer covering. In the hardness change treatment step, the inner layer covering and the outer layer covering are provided. If a process for changing the hardness is applied to at least one of these, various designs can be made by freely changing the hardness of the catheter tube having a multilayer structure.

  If a reinforcing body forming step for forming a reinforcing body made of a wire rod is further provided inside or outside in the radial direction from the covering body, the manufactured catheter tube can be reinforced according to the part, and the pushability and resistance can be increased. Kink property can be improved.

  In the core wire, a large-diameter portion and a small-diameter portion having different outer diameters are continuously formed in advance at a predetermined interval, and the outer diameter from the small-diameter portion toward the large-diameter portion is between the large-diameter portion and the small-diameter portion. If the transition part expands, the rigidity of the manufactured catheter tube changes smoothly and in an inclined manner along the axis, local bending is suppressed, and the pushability and kink resistance are excellent. A catheter tube can be manufactured.

  If the shape of the outer peripheral surface of the transition portion in the cross section along the axis of the core wire is formed with a curve, the rigidity of the manufactured catheter tube changes smoothly and inclined along the axis. In addition, it is possible to manufacture a catheter tube that is suppressed in local bending and excellent in pushability and kink resistance.

It is a top view which shows a catheter. It is sectional drawing which shows the tube for catheters manufactured by the manufacturing method of the tube for catheters concerning embodiment. It is a figure for demonstrating the manufacturing method of the tube for catheters which concerns on embodiment to process order, (A) is a core wire preparation process, (B) is an inner layer covering body formation process, (C) is a reinforcement body formation process, (D ) Shows an outer layer covering formation step, (E) shows a hydrophilic covering formation step, (F) shows a cutting step, (G) shows a core wire stretching step, and (H) shows a core wire removing step. It is the schematic for demonstrating the method of forming a layer by extrusion molding. It is the schematic for demonstrating the method of forming a layer by dip molding. It is the schematic for demonstrating the method of coat | covering a hydrophilic coating body by dip molding. It is a top view which shows the modification of a core wire. It is a top view which shows the other modification of a core wire.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the dimension ratio of drawing is exaggerated on account of description, and may differ from an actual ratio.

  A catheter tube 10 manufactured by the catheter tube manufacturing method according to the present embodiment is inserted into a blood vessel, bile duct, trachea, esophagus, urethra, or other living body lumen or body cavity as shown in FIG. It is used for the catheter 1 for performing treatment and diagnosis. The catheter 1 includes a long catheter tube 10, a hub 20 connected to the proximal end of the catheter tube 10, and a kink protector 30 provided at a connection portion between the catheter tube 10 and the hub 20. ing. In this specification, the side to be inserted into the lumen is referred to as “tip” or “tip side”, and the proximal side to be operated is referred to as “base end” or “base end side”.

  As shown in FIGS. 1 and 2, the catheter tube 10 is a flexible tubular member, a tube base end portion 11 located on the base end side, and an outer diameter and an inner diameter smaller than the tube base end portion 11. And a tube transition portion 13 whose outer diameter and inner diameter gradually change in the axial direction between the tube base end portion 11 and the tube tip end portion 12. The catheter tube 10 has a lumen 14 formed from the proximal end to the distal end. The lumen 14 functions as a guide wire lumen, for example, and the guide wire is inserted when the catheter 1 is inserted into the living body lumen. The lumen 14 can also be used as a passage for a chemical solution, an embolic material, a contrast medium, or the like.

  The catheter tube 10 is composed of a plurality of layers, an inner layer 15 constituting the innermost layer, a reinforcing layer 16 formed outside the inner layer 15, and an outer layer formed outside the inner layer 15 and the reinforcing layer 16. 17 and a hydrophilic layer 18 coated on the outer side of the outer layer 17. The outer layer 17 includes an outer layer proximal end portion 17A located at the tube proximal end portion 11, an outer layer transition portion 17B located at the tube transition portion 13, and an outer layer distal end portion 17C located at the tube distal end portion 12. The outer layer base end portion 17A, the outer layer transition portion 17B, and the outer layer front end portion 17C are all formed so that the thickness decreases in the direction from the base end side toward the front end side. The outer layer base end portion 17A, the outer layer transition portion 17B, and a part of the outer layer tip end portion 17C may be formed so that the thickness decreases in the direction from the base end side toward the tip end side. In the end portion 17A, it is preferable that the thickness decreases in the direction from the proximal end side toward the distal end side. The configuration and materials of the inner layer 15, the reinforcing layer 16, the outer layer 17, and the hydrophilic layer 18 will be described in detail in the manufacturing method described later.

  In the hub 20, the proximal end portion of the catheter tube 10 is fixed in a liquid-tight manner by an adhesive, heat fusion, a stopper (not shown) or the like. The hub 20 functions as an insertion port for a guide wire into the lumen 14, an injection port for a drug solution, an embolic material, a contrast medium, etc. into the lumen 14, and also functions as a grip portion when operating the catheter 1. To do. Although the material of the hub 20 is not particularly limited, for example, a thermoplastic resin such as polycarbonate, polyamide, polysulfone, polyarylate, methacrylate-butylene-styrene copolymer can be suitably used.

  The kink protector 30 is made of an elastic material provided so as to surround the circumference of the catheter tube 10, and suppresses kinking of the catheter tube 10 at a connection portion between the catheter tube 10 and the hub 20. As a material for the kink protector 30, for example, natural rubber, silicone resin, or the like can be preferably used.

  Next, a method for manufacturing a catheter tube according to this embodiment will be described. The catheter tube 10 includes a core wire preparation step (FIG. 3A) for preparing a long core wire 40, and an inner layer cover body formation step (cover body formation) for forming an inner layer cover body 51 (cover body) on the core wire 40. Step) (FIG. 3B), a first hardness change treatment step for subjecting the inner layer covering 51 to a hardness change process, and a reinforcing body forming step for forming the reinforcing member 52 on the inner layer covering 51 (FIG. 3C )), The outer layer covering body forming step (covering body forming step) (FIG. 3D) for integrally covering the reinforcing body 52 and the inner layer covering body 51 to form the outer layer covering body 53, and the outer layer covering body 53. A second hardness change treatment step for subjecting the (cover) to a hardness change treatment, a hydrophilic coat forming step for covering the hydrophilic coat 54 (FIG. 3E), and a tubular continuous body obtained on the core wire 40 A cutting work for cutting the single tube 61 by cutting 60 at a predetermined position of the core wire 40 (FIG. 3 (F)), a core wire extending step (FIG. 3 (G)) for extending the core wire 40, and a core wire removing step (FIG. 3 (H)) for removing the core wire 40 from each single tube 61. doing. The inner layer covering body 51, the reinforcing body 52, the outer layer covering body 53, and the hydrophilic covering body 54 formed on the core wire 40 constitute a covering body 50, and finally, the inner layer 15 and the reinforcing layer 16 of the catheter tube 10. The outer layer 17 and the hydrophilic layer 18 are formed.

  As shown in FIG. 3 (A), the core wire preparation step is performed by mechanical processing such as drawing, drawing, or the like using a cutting die, cutting, polishing, grinding, forging, welding, split die, or chemical processing such as etching. , A step of processing to have the large-diameter portion 41, the small-diameter portion 42, and the transition portion 43, or a step of preparing the core wire 40 subjected to the above-described processing by purchase or the like.

  The core wire 40 prepared in the core wire preparation step includes a large diameter portion 41 having a predetermined outer diameter, a small diameter portion 42 having an outer diameter smaller than the large diameter portion 41, and between the large diameter portion 41 and the small diameter portion 42. A plurality of transition portions 43 whose outer diameters gradually change in the axial direction of the core wire 40 are arranged side by side. The ratio of the outer diameter D1 of the large diameter portion 41 to the outer diameter D2 of the small diameter portion 42 (D1 / D2) is preferably more than 1.00 and 1.31 or less, more preferably 1.30 or less. More preferably 1.22 or less. The ratio (D1 / D2) is greater than 1. When the ratio (D1 / D2) is 1.31 or less, not only the small-diameter portion 42 but also the large-diameter portion 41 is satisfactorily stretched in the core wire stretching step, and the thinning of only the small-diameter portion 42 is suppressed. The core wire 40 can be removed well in the removing step, and the catheter tube 10 that can withstand actual use can be manufactured. If the ratio (D1 / D2) is 1.22 or less, the thinning of only the small-diameter portion 42 is more reliably suppressed, and the core wire 40 can be more reliably removed in the core wire removing step. The catheter tube 10 can be manufactured. As an example, the length L1 of the large diameter portion 41 is 1800 mm, the length L2 of the small diameter portion 42 is 150 mm, the length L3 of the transition portion 43 is 50 mm, and the outer diameter D1 of the large diameter portion 41 is 0.55 to. Although the outer diameter D2 of 6 mm and the thin diameter part 42 can be 0.45-0.50 mm, a dimension is not limited to this.

  The material of the core wire 40 can be a metal such as a copper wire or a stainless steel soft wire, or a resin strand such as polyamide (PA), and the cross section is not limited to a circle, but can be any shape such as an ellipse, a semicircle, a polygon, etc. It can be made into the shape.

  After the core wire preparation step, as shown in FIG. 3 (B), an inner layer covering 51 is formed on the core wire 40 (inner layer covering forming step). As the material of the inner layer covering 51, a thermoplastic resin, a thermosetting resin, or the like that can be cross-linked by an electron beam or a gamma ray can be applied, and a low friction material such as a fluorine-based resin or high-density polyethylene (HDPE) is preferable.

  The inner layer covering 51 may be mixed with a radiopaque material. When the inner layer covering 51 is formed of a low friction material such as a fluororesin, the outer surface of the inner layer covering 51 is roughened by chemical etching or the like so that other materials can be covered on the outer side. It is preferable to perform the treatment.

  When a thermoplastic resin is used as the material of the inner layer covering 51, it can be extruded at a predetermined take-up speed at a predetermined molding temperature (die temperature) with an extruder. Thereby, the extrusion molding (inner layer covering 51) of substantially the same thickness can be obtained. As an example, the outer diameter of the inner layer covering 51 in the portion corresponding to the large diameter portion 41 is 0.57 to 0.76 mm, and the outer diameter of the inner layer covering 51 in the portion corresponding to the small diameter portion 42 is 0.47 to 0. 0.53 mm, but the dimensions are not limited to this. In addition, by adjusting the take-up speed, the wall thickness can be changed according to the part.

  An outline of the extrusion molding method is as follows. Using a general extrusion molding machine 100 as shown in FIG. 4, a thermoplastic resin layer (here, inner layer covering 51) on the core material W (here, the core wire 40). ). The extrusion molding machine 100 includes an extruder 101 for extruding the heated and melted material, a mold 103 for extruding the resin extruded from the extruder 101 from the extrusion port 102, and a position passing through the mold 103 at the center of the extrusion port 102. A take-up machine 105 for picking up the core material W to be wound, a supply roll 106 for supplying the core material W to the mold 103 while the core material W is wound and held, and a recovery for recovering the core material W that has been extruded. A roll 107. When extruding a material onto the core material W, the material heated and melted by the extruder 101 is supplied to the mold 103, and sent from the supply roll 106 to take out the core material W located at the extrusion port 102. The material is continuously supplied from the extrusion port 102 onto the core material W while being taken up by 105, and the material is coated on the core material W. The core material W coated with the material is wound around the collection roll 107 and collected after the coated material is solidified. It is wound around a collection roll 107 and collected. By changing the take-up speed by the take-up machine 105, the outer diameter of the extruded product can be arbitrarily changed. If the core material W is directly received from the previous process and the core material W coated with the thermoplastic resin is directly transferred to the subsequent process, the supply roll 106 and the recovery roll 107 may not be provided. In the extrusion molding of the inner layer covering 51, when a fluororesin (such as PTFE) is used as the resin, it is possible to extrude a mixture of resin powder with a fluorolubricant as an auxiliary agent.

  In the inner layer covering body forming step, the inner layer covering body 51 may be formed by dip molding, not by extrusion molding. If the method by dip molding is outlined, first, in a container 200 as shown in FIG. 5, a solution R in which a resin as a material is dissolved in a solvent or a dispersion R in which a dispersion R is dispersed in a diluent is contained. Supply roll on which the core material W is wound and held via a flexible valve body 201 through which the core material W (here, the core wire 40) can be inserted while maintaining liquid tightness. The core material W is supplied from 202, and the core material W is inserted into the container 200 from below. Then, after the core material W is dipped (immersed) in the solution R or dispersion R in the container 200, the core 200 is pulled out above the container 200. As a result, the solution R or dispersion R is adhered to the outer peripheral surface of the core material W, and the solution R or dispersion R adhered to the core material W is heated and dried with hot air, a heater, etc. When the dispersion R is used, the inner layer covering 51 is formed by further sintering. The core material W coated with the material is wound around the collection roll 203 and collected after the coated material is solidified. As the solvent and diluent, those usually used can be applied. By changing the pulling speed from the container 200, the film thickness of the solution R or the dispersion R attached to the core material W can be arbitrarily changed, and the thickness of the inner layer covering 51 can be arbitrarily changed. The film thickness is determined by the interaction of the density, surface tension, viscosity, gravity and pulling speed of the solution R or dispersion R. When the pulling speed from the container 200 is decreased, the solution R attached to the core W is reduced. Alternatively, the film thickness of the dispersion R can be increased, and when the pulling rate is increased, the film thickness of the solution R or the dispersion R attached to the core material W can be decreased. For example, the film thickness of the part corresponding to the small diameter part 42 can be made thinner than the large diameter part 41, and the film thickness of the part corresponding to the transition part 43 can be gradually changed.

  Also, if the viscosity of the solution R or dispersion R is high, the coating thickness tends to be non-uniform, so the viscosity is set low enough to make the coating film thickness uniform, and dip molding is repeated multiple times. Thus, the coating thickness can be gradually increased, and the coating thickness can be controlled with high accuracy. When the dip molding is repeatedly performed, the recovery roll 203 from which the core material W coated with the material is recovered can be moved below the container 200 to be the supply roll 202, and the dip molding can be performed again. When the dip molding is repeated, it is preferable to dry and sinter the solution R or the dispersion R by heating with hot air or a heater every time.

  Further, when the dip molding is repeated a plurality of times, it is preferable that the dip molding is performed at least once in the opposite direction, rather than the dip molding by pulling up in the same direction of the core wire 40, more preferably once. It is preferable to perform dip molding while changing the direction one by one. By dipping from the opposite direction at least once, the film thickness can be made uniform by suppressing the unevenness of the film thickness depending on the pulling direction. The thickness deviation can be suppressed to the maximum and the film thickness can be made more uniform. In particular, in the core wire 40 whose outer diameter changes, the thickness 40 depending on the pulling direction is likely to occur in the portion where the outer diameter changes, so the core wire 40 in which the large diameter portion 41 and the small diameter portion 42 are formed. When the dip molding is performed, the dip molding is performed at least once from the opposite direction, so that a high effect can be achieved in making the film thickness uniform.

  In addition, although it can dry and sinter for every step of dip forming, it can also be dried and sintered after dip forming continuously several times without drying and sintering. Thus, the thickness in a desired part can be finely set by carrying out the dip molding continuously several times without drying and sintering.

  Further, when the dip molding is repeatedly performed, the number of repetitions can be changed according to the portion of the core wire 40. As an example of a method for this purpose, the portion where the number of repetitions is to be increased is pulled up, the solution R or dispersion R coated on the portion is dried and sintered, and then the core wire 40 that has moved upward is moved downward. And the part where the number of repetitions is to be increased is immersed in the solution R or the dispersion R. Thereafter, the core wire 40 is again moved upward, and the part where the number of repetitions is desired to be increased is again pulled up, so that the solution R or the dispersion R can be further coated. By repeating this, dip molding can be performed a desired number of repetitions according to the site. In this way, the number of repetitions of dip molding can be set as appropriate according to the site while switching the moving direction of the core wire 40. Therefore, for example, the number of repetitions of dip molding can be set so that transition portion> large diameter portion> small diameter portion or large diameter portion> transition portion> small diameter portion. A> B means that the number of repetitions in A is larger than the number of repetitions in B. Of these, it is preferable to perform dip molding so that the number of repetitions is maximized at the transition portion, because the thickness at the transition portion can be variably changed. Even in this method, drying and sintering can be performed for each step of dip molding, but drying and sintering may be performed after dip molding multiple times in succession without drying and sintering. .

  In addition, the core 40 is not moved, but the depth is changed by changing the amount H of the solution R or dispersion R shown in FIG. (Downward) can also be adjusted.

  In addition, the core material W is lifted from the container 200 while being rotated about the axis of the core material W, so that centrifugal force is applied to the solution R or dispersion R coated on the core material W to be coated. Can be arbitrarily changed. That is, the higher the rotational speed of the core material W, the greater the centrifugal force that acts, so that the film thickness of the solution R or dispersion R coated on the core material W can be reduced. The slower the centrifugal force acting, the more the film thickness of the solution R or dispersion R coated on the core material W can be increased. For example, by increasing the rotational speed at the time of pulling up the small diameter portion 42 rather than at the time of pulling up the large diameter portion 41, the film thickness covered by the small diameter portion 42 is changed to the film thickness covered by the large diameter portion 41. Can be made thinner. And when pulling up the transition part 43, the film thickness in the transition part 43 is changed smoothly and incline between the large diameter part 41 and the small diameter part 42 by changing the rotational speed of the core wire 40 gradually. be able to. Thereby, the distal end side of the manufactured catheter tube 10 can be made more flexible than the proximal end side. In addition, the larger the outer diameter of the core wire 40, the greater the centrifugal force that acts. Therefore, in order to make the film thickness of the solution R or dispersion R to be coated constant, the rotational speed is adjusted at the portion where the outer diameter changes. It is also possible to do.

  In the present embodiment, since the core material W is supplied from the supply roll 202 and is recovered by the recovery roll 203, the supply roll 202 and the recovery roll 203 can be rotated about the axis of the core material W in the container 200. However, the configuration of the apparatus is not limited as long as the core material W in the container 200 can be rotated.

  Further, when the core material W is pulled up from the container 200 while rotating, if a mixture of particles, fibers, and the like is mixed in the solution R or the dispersion R, the mixture can be oriented.

  When the dip forming is repeated a plurality of times while rotating, it is preferable to perform the dip forming while rotating the core wire 40 in the same direction each time instead of rotating at least once. It is preferable to perform dip molding while reversing the direction. By performing dip molding while rotating in reverse at least once, the film thickness can be made uniform by suppressing the deviation of film thickness depending on the rotation direction, and by rotating the rotation direction by changing the rotation direction one by one. The film thickness deviation depending on the thickness can be suppressed to the maximum, and the film thickness can be made more uniform.

  When it is desired to reduce the film thickness of the solution R or the dispersion R coated on the core material W, it is necessary to slow the pulling speed if it is controlled by the pulling speed. If it is controlled by speed, it can be adjusted by increasing the rotational speed without slowing the pulling speed, so that the manufacturing time can be shortened.

  Thus, the viscosity of the solution R or the dispersion R, the pulling speed, the pulling direction, the pulling site, the liquid amount of the solution R or the dispersion R (depth in the container 200), the number of repetitions of dip molding, the rotation speed, and By adjusting the rotation direction, the coating thickness and manufacturing time of the inner layer covering 51 to be coated can be controlled with high accuracy.

  In addition, if the inner layer covering 51 can be dip-molded, the container 200 does not have to be as described above. For example, the core material W is not inserted through the bottom of the container 200 but from above the container. May be dipped (immersed) in the solution R or the dispersion R, and the core material W may be curved and pulled up again. Further, after the solution R or the dispersion R is attached to the outer peripheral surface of the core material W, the amount of the solution R or the dispersion R to be attached is regulated by passing through a die (not shown) having a predetermined inner diameter. Thus, the outer diameter of the inner layer covering 51 can be adjusted. Further, if the core material W is directly received from the previous process and the core material W coated with the material is directly transferred to the subsequent process, the supply roll 202 and the recovery roll 203 around which the core material W is wound are not provided. May be.

  Further, the method for forming the inner layer covering 51 in the inner layer covering forming step is not limited to extrusion molding or dip molding. For example, a solution in which a resin is dissolved in a solvent or a dispersion in which a dispersion is dispersed in a diluent is sprayed. (Spray), application, printing, etc., after attaching to the core wire 40, the solution or dispersion attached to the core wire 40 is heated and dried with hot air or a heater, and depending on the material, it may be sintered. The inner layer covering 51 may be formed.

  After the inner layer covering body forming step, a first hardness change processing step is performed in which the inner layer covering body 51 is subjected to a processing for changing the hardness. In the first hardness change treatment step, a portion corresponding to the large diameter portion 41 of the inner layer covering 51 is irradiated with an electron beam or gamma ray, and a curing treatment is performed to increase the hardness by crosslinking the material. The degree of increase in the hardness of the inner layer covering 51 can be adjusted by controlling the intensity of the electron beam or gamma ray and the irradiation time. Therefore, for example, it is manufactured by gradually decreasing the irradiation amount (intensity × irradiation time) of the electron beam or gamma ray from one side of the portion corresponding to the large diameter portion 41 of the inner layer covering 51 to the other side. From the proximal end side of the tube proximal end portion 11 of the catheter tube 10 to the distal end side, the rigidity is lowered smoothly and in an inclined manner, local bending is suppressed, and pushability and kink resistance are improved. be able to.

  Further, in the first hardness change treatment step, a softening treatment is performed on the portion corresponding to the small diameter portion 42 of the inner layer covering 51 by using acid or alkali to reduce the hardness. For example, dilute sulfuric acid can be used as the acid, and sodium hydroxide or the like can be used as the alkali. The degree of decrease in the hardness of the inner layer covering 51 can be adjusted by controlling the solution concentration when applying acid or alkali to the application site, the application time, and the like. Therefore, for example, from one side of the portion corresponding to the small diameter portion 42 of the inner layer covering body 51 to the other side, the rigidity is smoothly and gradually lowered to form a flexible structure, and local bending is suppressed. Thus, while maintaining the pushability and kink resistance of the manufactured catheter tube 10, it is possible to improve reachability to a small-diameter site such as a peripheral blood vessel and followability to a guide wire. In the present embodiment, both the curing process and the softening process are performed in the first hardness change process, but only one of the processes may be performed. Moreover, not only the site | part corresponding to the large diameter part 41 of the inner layer coating | coated body 51 but the site | part corresponding to the small diameter part 42 and the transfer part 43 may be given to a hardening process. Further, not only the portion corresponding to the small diameter portion 42 of the inner layer covering 51 but also the portions corresponding to the large diameter portion 41 and the transition portion 43 may be softened.

  After the first hardness change treatment step, as shown in FIG. 3C, the reinforcing body 52 is formed so as to cover at least part of the inner layer covering body 51 (reinforcing body forming step).

  The reinforcing body 52 is formed on the inner layer covering body 51 by continuously winding a strand with a braid having a predetermined interstitial distance. The reinforcing body 52 may be wound with strands while changing the winding direction, such as horizontal winding in the same direction, right-hand winding, left-hand winding, etc., and the winding pitch, interstitial distance, inclination angle with respect to the circumferential direction, etc. The configuration may be changed, and the configuration is not particularly limited.

  As the strands used for the reinforcing body 52, metal wires such as platinum (Pt) / tungsten (W), resin fibers, carbon fibers, glass fibers and the like can be applied, or a plurality of these strands may be used in combination. .

  After the reinforcing body forming step, as shown in FIG. 3D, at least a part of the inner layer covering body 51 and the reinforcing body 52 is covered to form an outer layer covering body 53 (outer layer covering body forming step). In the reinforcing body forming step, the outer periphery of the inner layer covering 51 and the reinforcing body 52, ie, the outer circumference in the radial direction of the inner layer covering 51 is coated with the thermoplastic resin as a material while changing the thickness by extrusion molding. The body 53 is molded. The outer layer covering 53 is coated such that the thickness decreases in the direction from the large diameter portion 41 of the core wire 40 toward the one small diameter portion 42. Thereby, the rigidity of the catheter tube 10 to be manufactured is lowered smoothly and inclined from the proximal end side toward the distal end side, suppressing local bending, and maintaining the pushability and kink resistance, Reachability to a small-diameter site such as a peripheral blood vessel and followability to a guide wire can be improved. As an example, the thickness A1 on one side of the portion corresponding to the large diameter portion 41 of the outer layer covering 53 is 0.08 to 0.1 mm, and the thickness A2 on the other side of the portion corresponding to the large diameter portion 41 is 0. 0.06 to 0.08 mm, the thickness A3 on one side of the portion corresponding to the small diameter portion 42 is 0.04 to 0.06 mm, and the thickness A4 on the other side of the portion corresponding to the small diameter portion 42 is 0.02 ˜0.04 mm, and A1> A2> A3> A4. As specific numerical examples when A1> A2> A3> A4, A1 = 0.1 mm, A2 = 0.08 mm, A3 = 0.04 mm, and A4 = 0.02 mm. As another example, A1> A2> A3> A4 can be set, and as specific numerical examples in this case, A1 = 0.1 mm, A2 = 0.08 mm, A3 = 0.02 mm, A4 = 0 .04 mm.

  The material of the outer layer covering 53 is, for example, polyolefin (for example, polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more thereof), polyvinyl chloride, A thermoplastic resin that can be cross-linked by electron beams or gamma rays, such as a polymer material such as polyamide, polyester elastomer, polyamide elastomer, polyurethane, polyurethane elastomer, polyimide, fluororesin, or a mixture thereof, can be applied. The outer layer covering 53 may be mixed with a radiopaque material.

  When the outer layer covering 53 is extruded, the above-described extrusion molding machine 100 as shown in FIG. 4 is used to coat the core wire 40 with the inner layer covering 51 and the reinforcing member 52 (FIG. 3C). The outer layer covering 53 can be extruded using the core material W as a reference). In extrusion molding, the thickness of the outer layer covering 53 to be formed can be reduced by increasing the take-up speed, and the thickness of the outer layer covering 53 to be formed can be increased by reducing the take-off speed. By extruding while changing the take-up speed, the outer layer covering 53 whose thickness changes in the axial direction of the core wire 40 can be formed.

  Further, in the outer layer covering body forming step, the outer layer covering body 53 is not formed by extrusion molding, but the core wire 40 is covered with the inner layer covering body 51 and the reinforcing body 52 using the container 200 as shown in FIG. The outer layer covering 53 can be dip-molded using the structure (see FIG. 3C) as the core material W.

  The method of forming the outer layer covering 53 in the outer layer covering forming step is not limited to extrusion molding or dip molding. For example, a solution in which a resin is dissolved in a solvent or a dispersion in which a resin is dispersed in a diluent is sprayed. (Spray), application, printing, and the like, after attaching to the outer peripheral surface of the reinforcing body 52, the attached solution or dispersion is heated and dried with hot air or a heater, and depending on the material, it may be sintered. Thus, the outer layer covering 53 may be formed.

  When the outer layer covering 53 is formed by a method other than extrusion molding, the material of the outer layer covering 53 is not limited to a thermoplastic resin. For example, thermosetting that can be cross-linked by an electron beam such as an epoxy resin or gamma rays. Resin etc. can also be applied.

  In addition, you may remove a part of reinforcement body 52 before an outer layer covering body formation process. For example, in order to ensure the flexibility of the distal end portion of the catheter tube 10, a part of the reinforcing body 52 corresponding to the small diameter portion 42 can be removed.

  After the outer layer covering formation process, a second hardness change processing step is performed in which the outer layer covering 53 is subjected to a process of changing the hardness. In the second hardness change treatment step, a portion corresponding to the large diameter portion 41 of the outer layer covering 53 is irradiated with an electron beam or gamma ray, and a curing treatment is performed to increase the hardness by crosslinking the material. The degree of increase in the hardness of the outer layer covering 53 can be adjusted by controlling the intensity of the electron beam or gamma ray and the irradiation time. Therefore, for example, by gradually decreasing the irradiation amount of the electron beam or the gamma ray from one side of the portion corresponding to the large diameter portion 41 of the outer layer covering 53 to the other side, the manufactured tube 10 for the catheter is manufactured. From the proximal end side to the distal end side of the tube proximal end portion 11, the rigidity can be reduced smoothly and in an inclined manner, local bending can be suppressed, and pushability and kink resistance can be improved.

  Further, in the second hardness change treatment step, a softening treatment is performed on the portion corresponding to the small diameter portion 42 of the outer layer covering 53 by using acid or alkali to reduce the hardness. For example, dilute sulfuric acid can be used as the acid, and sodium hydroxide or the like can be used as the alkali. The degree of decrease in the hardness of the outer layer covering 53 can be adjusted by controlling the solution concentration when applying acid or alkali to the application site, the application time, and the like. Therefore, for example, a catheter manufactured by reducing the rigidity smoothly and inclined from one side of the portion corresponding to the small-diameter portion 42 of the outer layer covering 53 to the other side and suppressing local bending. The pushability and kink resistance of the tube 10 can be maintained, and reachability to a small-diameter site such as a peripheral blood vessel and followability to a guide wire can be improved. In the present embodiment, both the curing process and the softening process are performed in the second hardness change process, but only one of the processes may be performed. Further, not only the portion corresponding to the large-diameter portion 41 of the outer layer covering 53 but also the portions corresponding to the small-diameter portion 42 and the transition portion 43 may be subjected to curing treatment. Further, not only the portion corresponding to the small-diameter portion 42 of the outer layer covering 53 but also the portions corresponding to the large-diameter portion 41 and the transition portion 43 may be softened.

  After the second hardness change treatment step, as shown in FIG. 3E, a hydrophilic polymer substance (hydrophilic material) is coated on the tip side of the outer layer covering 53 to form a hydrophilic covering 54. (Hydrophilic covering forming step). The hydrophilic covering 54 finally constitutes the hydrophilic layer 18 (see FIG. 2) on the outer surface of the catheter tube 10. The hydrophilic layer 18 exhibits lubricity when contacted with a liquid such as blood or physiological saline, reduces the frictional resistance of the catheter tube 10, and further improves the slidability. And the pushability, followability, kink resistance and safety are further improved.

  Further, when inserting the catheter tube 10 into a blood vessel, it is necessary to operate the catheter tube 10 by holding the proximal end side of the catheter tube 10 in a hand. For this reason, if the base end side of the catheter tube 10 slips when held by hand, the operability is lowered, which is not preferable. For this reason, the range in which the hydrophilic layer 18 in the longitudinal direction of the catheter tube 10 is provided excludes a predetermined length (for example, about 150 to 500 mm) from the proximal end of the catheter tube 10 toward the distal end. It is preferable that it is a region. Therefore, the hydrophilic covering 54 covered on the outer peripheral surface of the outer covering 53 is covered on a part of the outer covering 53 so that the hydrophilic layer 18 is provided in the above range. Specifically, a plurality of coating ranges B corresponding to a part of the large-diameter portion 41 and the small-diameter portion 42 are provided at predetermined intervals along the axial direction of the core wire 40, and these coating ranges B are hydrophilicly coated. Form body 54. Thereby, a tubular continuous body 60 including the inner layer covering body 51, the reinforcing body 52, the outer layer covering body 53, and the hydrophilic covering body 54 is formed on the core wire 40. The configuration including the core wire 40 in the tubular continuous body 60 is referred to as a catheter tube continuous body 65.

  Examples of the hydrophilic polymer substance include the following natural or synthetic polymer substances or derivatives thereof. In particular, cellulosic polymer materials (eg, hydroxypropyl cellulose), polyethylene oxide polymer materials (polyethylene glycol), maleic anhydride polymer materials (eg, maleic anhydride such as methyl vinyl ether maleic anhydride copolymer) Copolymers), acrylamide polymer substances (for example, polyacrylamide), and water-soluble nylon (for example, AQ-nylon P-70 manufactured by Toray Industries, Inc.) are preferable because a low friction coefficient can be stably obtained. Among these, a maleic anhydride polymer material is more preferably used. Further, the derivative of the polymer substance is not limited to a water-soluble derivative, and there is no particular limitation as long as the polymer substance has a basic configuration, and even if it is insolubilized, the molecular chain has a degree of freedom. As long as it has water and contains water.

  In order to fix such a hydrophilic polymer substance to the outer surface of the catheter tube 10, it is covalently bonded to a reactive functional group present or introduced in the outer layer covering 53 or on the surface of the outer layer covering 53. It is preferable to carry out. Thereby, a continuous lubricating surface can be obtained.

  The reactive functional group present in or introduced into the outer layer covering 53 or on the surface thereof may be any one that reacts with the hydrophilic polymer substance and is fixed by being bonded or cross-linked, such as a diazonium group. , Azide group, isocyanate group, acid chloride group, acid anhydride group, imino carbonate group, amino group, carboxyl group, epoxy group, hydroxyl group, aldehyde group, and the like. Among these, as the reactive functional group, an isocyanate group, an amino group, an aldehyde group, and an epoxy group are more preferable.

  In the hydrophilic covering forming step, the hydrophilic covering 54 can be formed by dip molding using the core W as a structure in which the inner layer covering 51, the reinforcing body 52, and the outer covering 53 are coated on the core wire 40. . In dip molding, the apparatus 300 shown in FIG. 6 can be used. The apparatus 300 collects the container 301 containing a solution R2 in which a hydrophilic polymer material is dissolved in a solvent, the supply roll 302 for supplying the core W, and the core W coated with the hydrophilic covering 54. And a collection roll 303. The core material W extends downward from the supply roll 302, curves in a U shape at the lower end, extends upward, and reaches the recovery roll 303. Examples of the solvent that can be used include dimethylformamide, dimethyl sulfoxide, and tetrahydrofuran.

  When the core material W is coated with the hydrophilic coating 54, when the core material W is not immersed in the solution R 2 and the recovery roll 303 is stopped and the core material W is supplied from the supply roll 302, the coating range B After positioning the core material W at a position where only the material R2 is immersed in the solution R2, the supply by the supply roll 302 and the recovery by the recovery roll 303 are stopped to fix the core material W (see the one-dot chain line in FIG. 6). Next, the coating area B is immersed in the solution R2 by supplying the core material W from the supply roll 302 in a state where the collection roll 303 is stopped. After a predetermined time has passed, the supply roll 302 is stopped, the core material W is wound up by the collection roll 303, and the core material W is pulled up from the solution R2. The solution R2 attached to the core material W is naturally dried or dried by heating with hot air, a heater, or the like, and the hydrophilic covering 54 is covered only in the covering range B. Thereafter, in order to coat the hydrophilic coating 54 in the next coating range B provided at a predetermined interval, the supply roll 302 and the recovery roll 303 are operated so that only the coating range B can be immersed in the solution R2. After the core material W is moved to position the core material W, the supply by the supply roll 302 and the recovery by the recovery roll 303 are stopped to fix the core material W. Thereafter, by repeating the above steps, the core material W can be coated with the hydrophilic covering 54 at a predetermined interval. As long as the hydrophilic covering 54 can be formed, the forming method is not limited. For example, the hydrophilic covering 54 may be coated by a known method such as spraying, spraying, coating, printing, or the like.

  The hydrophilic covering forming step may be performed after the core wire stretching step or the core wire removing step. The hydrophilic covering forming step may be performed after the hub 20 and the kink protector 30 are connected to the manufactured catheter tube 10.

  After the hydrophilic covering forming process, as shown in FIG. 3F, the tubular continuous body 60 is cut together with the core wire 40 at a predetermined position (cutting process). The tubular continuous body 60 includes a first cutting portion 63 close to one end of the large diameter portion 41 and a second cutting portion on the small diameter portion 42 close to the first cutting portion 63 across the transition portion 43. 64 and cut. Thereby, the single tube 61 from which the large diameter part 41 is cut long and the surplus tube 62 from which the large diameter part 41 is cut short are formed. The single tube 61 corresponds to one catheter tube 10 and is an intermediate body before reaching the catheter tube 10. The surplus tube 62 is removed as an unnecessary portion. As described above, since the hydrophilic covering 54 is formed before the cutting step, it is not necessary to re-position the single tube 61 cut out to form the hydrophilic covering 54 after cutting, so that the work can be performed. The number of times of positioning can be reduced, and the catheter tube 10 can be manufactured efficiently. As an example of the dimensions of the single tube 61, the length of the portion corresponding to the large diameter portion 41 of the core wire 40 is 1600 mm, and the length of the portion corresponding to the small diameter portion 42 of the core wire 40 is 100 mm. In addition, the large diameter part 41 and the small diameter part 42 of the core wire 40 can be set long so that the surplus tube 62 has the same shape as the single tube 61, and the surplus tube 62 can also be used as the single tube 61.

  In the cutting step, for example, the cutting is performed with a cutting blade by a shearing machine or the like, but any cutting method may be used as long as the core wire 40 and the tubular continuous body 60 can be cut.

  After the cutting step, as shown in FIG. 3 (G), a part of the covering at both ends of the core wire 40 cut in the cutting step is removed, and a part of both ends of the core wire 40 is exposed before stretching. And the entire core wire 40 is stretched (core wire stretching step). Thereafter, as shown in FIG. 3H, the core wire 40 is pulled out from the large diameter portion 41 side (core wire removing step). Thereby, manufacture of the tube 10 for catheters is completed. In addition, after extending | stretching until the core wire 40 fractures | ruptures in the small diameter part 42 with an extending | stretching machine, you may pull out the broken core wire 40 from the large diameter part 41 side and the both sides of the small diameter part 42.

  As described above, in the method for manufacturing the catheter tube 10 according to the present embodiment, the covering 50 is coated on the core wire 40, and the covering 50 (the inner covering 51 and the outer covering 53) is changed in hardness. In order to cut the tubular continuous body 60 at a predetermined position and cut out the plurality of single tubes 61, it is not necessary to re-position the cut single tubes 61 to form a hardness change process after cutting, The number of times of positioning for performing the work can be reduced, and the rigidity can be set efficiently and effectively while continuously manufacturing the plurality of catheter tubes 10 using the same core wire 40.

  In addition, the tubular continuous body 60 including the inner layer covering body 51, the reinforcing body 52, the outer layer covering body 53, and the hydrophilic covering body 54 corresponding to the plurality of catheter tubes 10 is integrally formed on the same core wire 40 at a time. , Excellent in productivity.

  As a method of manufacturing the catheter tube 10, a hot stretching process is generally performed in which a tube body is subjected to a hot stretching process to reduce the inner and outer diameters from the proximal end side to the distal end side. When hot stretching is performed, residual strain due to hot stretching is affected during hot melt processing such as when attaching a soft tip or contrast marker, and the inner and outer diameters in the vicinity of the melted part become thick, resulting in poor dimensional accuracy. As a result, there are problems such as a decrease in yield. On the other hand, according to the manufacturing method according to the present embodiment, since the hot stretching process is not performed, there is no distortion due to stretching, the workability is improved, and as a result, the cost is reduced. In addition, since the winding pitch of the reinforcing body 52 (interstitial distance in the case of braiding) does not increase due to stretching, the tip portion is excellent in flexibility and kink resistance.

  In addition, the treatment for changing the hardness includes at least one of a hardening treatment for increasing the hardness by crosslinking the material by irradiation with electron beam or gamma ray, and a softening treatment for reducing the hardness using an acid or alkali. Alternatively, the hardness of the inner layer covering body 51 and the outer layer covering body 53 can be freely changed by the softening treatment.

  Further, since the large diameter portion 41 and the small diameter portion 42 having different outer diameters are continuously formed at predetermined intervals in the core wire 40, the catheter tube 10 having different diameters at the distal end side and the proximal end side is continuously connected. Therefore, it can be manufactured efficiently and easily by using the continuous tubular continuum 60.

  Further, in the hardness change processing step, since a hardening process for increasing the hardness is performed on the portions corresponding to the large-diameter portions 41 of the inner layer covering body 51 and the outer layer covering body 53, the tube base end portion 11 of the manufactured catheter tube 10 is processed. Hardness can be increased to improve indentability and kink resistance.

  Further, in the hardness change processing step, the hardness of the tube distal end portion 12 of the catheter tube to be manufactured is applied to the portion corresponding to the small diameter portion 42 of the inner layer covering body 51 and the outer layer covering body 53 to reduce the hardness. And the reachability to the peripheral blood vessels and the followability to the guide wire can be improved.

  The covering 50 has an inner covering 51 and an outer covering 53 that is coated on the outer side in the radial direction of the inner covering 51. In the hardness change processing step, the covering 50 is provided. Since the process of changing the hardness is performed on at least one of the body 51 and the outer layer covering body 53, the hardness of the catheter tube 10 having a multilayer structure can be freely changed to allow various designs.

  Moreover, since it has the reinforcement body formation process which forms the reinforcement body 52 which consists of a wire in the radial direction inner side or outer side of the coating body 50 (the inner layer coating body 51, the outer layer coating body 53), the manufactured tube 10 for catheters is site | part. Can be reinforced in accordance with the above, and the pushability and kink resistance can be further improved.

  Moreover, since the core wire 40 has the transition part 43 in which an outer diameter expands toward the large diameter part 41 from the small diameter part 42 between the large diameter part 41 and the small diameter part 42, the rigidity of the catheter tube 10 manufactured is manufactured. Changes smoothly and in an inclined manner along the axis of the catheter tube 10, local bending is suppressed, and the catheter tube 10 having excellent pushability and kink resistance can be manufactured.

  Note that the present invention is not limited to the above-described embodiments, and various modifications can be made by those skilled in the art within the technical idea of the present invention. For example, a transition portion 83 between the large-diameter portion 81 and the small-diameter portion 82 may be provided only on one end side of the large-diameter portion 81 as in a core wire 80 as a modified example shown in FIG. Thereby, the length of the surplus tube (see the surplus tube 62 in FIG. 3F) to be removed after cutting is shortened, and the cost can be reduced and the manufacturing area can be saved.

  Moreover, at least a part of the shape of the outer peripheral surface of the transition portion 93 in the cross section along the axis of the core wire 90 may be formed as a curve, like a core wire 90 as another modified example shown in FIG. Thereby, the rigidity of the manufactured catheter tube changes smoothly and in an inclined manner along the axis, and local bending is suppressed to maintain the pushability and kink resistance of the manufactured catheter tube 10. Meanwhile, it is possible to improve the reachability to a small-diameter site such as a peripheral blood vessel and the followability to the guide wire. In FIG. 8, the inclination angle X of the outer peripheral surface of the transition portion 93 in the cross section along the axis of the core wire 90 gradually increases from the small diameter portion 92 toward the large diameter portion 91. It becomes the maximum, and gradually becomes smaller as it gets closer to the large-diameter portion 91. By adopting such a shape, the rigidity along the axis between the large-diameter portion 91 and the small-diameter portion 92 can be changed more smoothly and in an inclined manner, and the local bending is suppressed and manufactured. While maintaining the pushability and kink resistance of the catheter tube 10, it is possible to improve reachability to a small-diameter site such as a peripheral blood vessel and followability to a guide wire.

  Further, a radiopaque marker may be arranged between the inner layer covering body 51 and the reinforcing body 52, or between the outer layer covering body 53 and the reinforcing body 52, or on the outer layer covering body 53. In addition, each of the reinforcing body 52, the outer layer covering body 53, and the hydrophilic covering body 54 may not be formed.

  Further, at least one of the inner layer covering 51 and the outer layer covering 53 may be irradiated with an electron beam or gamma ray to crosslink the material to increase the hardness. Further, at least one of the inner layer covering body 51 and the outer layer covering body 53 may be subjected to a softening process for reducing the hardness using an acid or an alkali.

  Further, the core wire may be formed with a constant outer diameter without providing the small diameter portion and the large diameter portion. When the core wire has a constant outer diameter, the core wire removal step can be performed before the cutting step.

  Further, the cross-sectional shape of the catheter tube in the cross section perpendicular to the axis may not be circular, and may be, for example, elliptical. Further, the lumen in the catheter tube may not have a circular cross-sectional shape in the cross section perpendicular to the axis, and may be, for example, an elliptical shape or a semicircular shape. The catheter tube may be provided with a plurality of lumens.

1 catheter,
10 Catheter tube,
40, 80, 90 core wires,
41, 81, 91 Large diameter part,
42, 82, 92 Small diameter part,
43, 83, 93 Transition section,
50 covering,
51 inner layer covering,
52 reinforcements,
53 outer layer covering,
54 hydrophilic covering,
60 tubular continuum,
61 Single tube,
63 1st cutting part,
64 second cutting part,
B Covering range.

Claims (9)

A covering forming step of forming a covering by coating a resin on the core wire;
A hardness change treatment step for applying a treatment to change the hardness of the covering;
A cutting step of cutting a plurality of single tubes by cutting a tubular continuous body obtained by providing the covering on the core wire after the hardness change treatment step at a predetermined position;
And a core wire removing step of removing the core wire from the single tube.   The process for changing the hardness includes at least one of a curing process for increasing the hardness by crosslinking the material by irradiation with an electron beam or a gamma ray, and a softening process for decreasing the hardness using an acid or an alkali. The manufacturing method of the tube for catheters of description.   The said core wire is a manufacturing method of the tube for catheters of Claim 1 or 2 in which the large diameter part and thin diameter part from which an outer diameter differs are continuously formed in advance at predetermined intervals.   The manufacturing method of the catheter tube of Claim 3 which performs the hardening process which raises hardness to the site | part corresponding to the said large diameter part of the said covering in the said hardness change process process.   The method for manufacturing a catheter tube according to claim 3 or 4, wherein, in the hardness change treatment step, a softening treatment for reducing hardness is performed on a portion corresponding to the small diameter portion of the covering. The covering has an inner layer covering that is coated on the core wire and an outer layer covering that is coated on the outer side in the radial direction than the inner layer covering,
The method for producing a catheter tube according to any one of claims 1 to 5, wherein in the hardness change treatment step, at least one of the inner layer covering body and the outer layer covering body is subjected to a treatment for changing hardness.   The manufacturing method of the catheter tube of any one of Claims 1-6 which further has the reinforcement body formation process which forms the reinforcement body which consists of a wire rod in the radial direction inner side or the outer side rather than the said coating | coated body.   The core wire has a large-diameter portion and a small-diameter portion having different outer diameters formed in advance continuously at a predetermined interval, and an outer diameter from the small-diameter portion toward the large-diameter portion between the large-diameter portion and the small-diameter portion. The manufacturing method of the tube for catheters of any one of Claims 1-7 which has the transition part which spreads.   The method for manufacturing a catheter tube according to claim 8, wherein the shape of the outer peripheral surface of the transition portion in a cross section along the axis of the core wire has a curve.

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