JP5626855B2 - Manufacturing method of medical tube - Google Patents

Description

  The present invention relates to a medical tube that is thin, flexible, excellent in kink resistance and tensile strength, and a manufacturing method thereof.

  A catheter inserted percutaneously into a blood vessel is guided to organs such as the brain, heart, and abdomen, and administration of therapeutic agents, embolic substances, contrast agents, etc., injection, delivery of endoscopes, other catheters, guide wires, etc. The medical practice of sucking blood clots and the like has been conventionally performed. In recent years, medical advances have led to the treatment of smaller peripheral blood vessels and less invasive treatments using catheters with smaller outer diameters. Catheters are needed. The performance of the catheter includes pushability, which reliably transmits the push force of the operator to the tip of the catheter, and reachability to the thinly bent peripheral blood vessels. The inner diameter of the catheter is very important for aspiration, delivery of endoscopes and other catheters. Furthermore, in order to carry out a minimally invasive treatment, it is necessary to reduce the outer diameter, and thus a very thin tube is required. Up to now, with such a thin tube, the kink resistance does not cause the catheter to be bent even at the bent or curved part of the blood vessel, the lumen maintenance at the time of high bending, and easy when the catheter is caught in the body. It was very difficult to secure the tensile strength to prevent breakage.

  Conventionally, resin tubes with a coil structure as a reinforcing layer have been studied as a tube excellent in kink resistance and lumen maintenance at high bends. It has excellent cavity maintenance, but is inferior in tensile strength. Therefore, in order to ensure the tensile strength of the tube using the coil structure, it is necessary to make the resin tube very thick or to provide a highly rigid resin. However, if the wall thickness is increased, the outer diameter becomes larger or the inner diameter becomes smaller, so that it cannot be inserted into thinner peripheral blood vessels, cannot perform minimally invasive treatment, and the performance of injectability, aspiration property, delivery property is deteriorated, etc. When a rigid resin is used, the toughness is generally low, the resin layer is cracked at the time of high bending, the kink resistance and tensile strength are lowered, and there is a problem that it cannot be used safely.

  As a method of improving the tensile strength of a tube having a coil structure as a reinforcing layer, a method of using an axial member in the longitudinal direction of the catheter is disclosed. Patent Document 1 describes a vascular catheter that further includes an axial member extending along a reinforcing layer made of a blade. By inserting an axial member, the shaft can be prevented from extending. The axial member is also not fixed to any polymer layer adjacent to the blade. However, this method certainly prevents the axial extension, but for higher tensile forces, it is necessary to increase the strand strength of the axial member, and the bending rigidity becomes unidirectional. There is a possibility. Moreover, about the axial direction member to the coil structure wound spirally, the protrusion along the length direction of a catheter will be formed so that concern may be made in this literature.

  As another method, a method of providing a braided structure outside the coil structure is disclosed. In Patent Document 2, a metal flat square braid is formed on the outside of a metal flat plate coil and a resin coating layer is formed on the outside thereof. The purpose is to achieve both the compression resistance during bending due to the coil structure and the tensile resistance due to the braided structure. However, if the thickness or width of the strands constituting the braid is increased against a high tensile force, the coil structure Since the compression resistance at the time of bending is reduced, it is difficult to apply to the catheter tip side where flexibility and high tensile force are required.

  These techniques have a structure that requires a reinforcing layer in addition to the coil layer and the resin layer, and could not be applied to thin tubes.

Japanese translation of PCT publication No. 2002-535049 JP-A-4-183478

  An object of the present invention is to stably provide a thin, flexible, medical tube excellent in kink resistance and tensile strength by an easy manufacturing method.

As a result of earnest research to solve the above problems, the present inventor,
A method of manufacturing a medical tube having a coil layer on the inside of the outer tube made of tree butter, by adding a first step of preparing a coil, stretched in the coil, and / or twisting, reduced diameter state The outer layer tube can be slid on the coil by releasing the reduced diameter by unwinding and / or twisting the coil in the outer layer tube. And a fourth step of applying an external force from both ends of the coil after releasing the extension and diameter reduction of the coil. did.

According to this, a thin, flexible, medical tube excellent in kink resistance and tensile strength can be easily and stably manufactured.

Further, it is desirable that the outer diameter of the coil in the first step is larger than the inner diameter of the outer layer tube.

Moreover, it is desirable that the coil pitch of the coil prepared in the first step is constant .

Further, the inner diameter of the outer layer tube is changed in at least two stages of a first inner diameter and a second inner diameter, so that in the third step, the coil pitch in the outer layer tube of the first inner diameter and the second It is desirable to have different coil pitches in the outer tube of inner diameter .

Further, it is desirable that the coil in the outer layer tube having the first inner diameter is closely wound, and the coil in the outer layer tube having the second inner diameter is pitch wound .

In the method for producing a medical tube having a coil layer on the inside of the outer tube made of a resin, on a coil prepared by winding the wire while applying a tension to the strand, placing the outer tube, the tension The outer tube may be contacted and fixed on the coil in a slidable state .

In addition, it is desirable to have a second outer layer made of a material having a lower melting point than the outer layer tube outside the outer layer tube .

By the way, it can be said that the medical tube characterized by being manufactured by any one of the manufacturing methods described above is also the present invention.

In addition, a medical device characterized in that it has at least a part of the medical tube can be said to be the present invention.

  As described above, according to the present invention, it is possible to stably provide a thin, flexible, medical tube excellent in kink resistance and tensile strength by an easy manufacturing method. As a result, it can be effectively used as a component part of medical devices such as various catheters.

It is the schematic of the medical tube which concerns on this invention. It is the elements on larger scale of the medical tube which concerns on this invention. It is the elements on larger scale of the prior art.

  Below, the manufacturing method of the medical tube which concerns on this invention, and the medical tube produced by the manufacturing method are demonstrated. The present invention is a method for manufacturing a medical tube, wherein the coil is stretched inside the outer layer tube made of resin or inserted in a state where the diameter is reduced by adding a twist, and the coil is stretched in the outer layer tube. Alternatively, the present invention relates to a method of manufacturing a medical tube, wherein the outer diameter tube is slidably contacted and fixed on the coil layer by untwisting and releasing the diameter reduction. In the present invention, “contact and fix in a slidable state” means that the medical tubes are in contact with each other and do not slide against each other due to frictional force or the like when no stress such as elongation or bending is applied to the medical tube. Means that when stress is applied, they can slide independently of each other before cracking or breaking in the outer tube, preferably before plastic deformation of the outer tube occurs . According to such a manufacturing method, it is possible to easily provide a thin, flexible, medical tube having excellent kink resistance and tensile strength without using a special structure or manufacturing method for reinforcing tensile strength. It becomes possible. The medical tube of the present invention has a structure in which the outer surface of the coil and the inner surface of the outer layer tube are contacted and fixed in a slidable state. In other words, the coil is inserted in a state where the coil is stretched or twisted to reduce the diameter, and the coil is stretched or twisted in the outer layer tube to release the diameter reduction, thereby removing the coil between the outer layer tube and the coil layer. A state in which the coil layer is slidably contacted and fixed is formed, and the outer surface of the coil layer and the inner surface of the outer tube are not fixed. As a result, when the medical tube is pulled and stretched, the coil and the outer layer tube are not fixed and can be slid so that they can take different behaviors, and the outer layer tube can be a single layer resin tube. The tensile strength and tensile elongation can be ensured. In addition, even when the medical tube is bent at a high degree of bending, the coil and the outer layer tube behave differently, and good kink resistance can be ensured. FIG. 1 shows a schematic view of a medical tube according to the present invention (a pitch winding coil described later). Here, the term “adhesion” means that when a stress such as a tensile stress is generated on the formed medical tube, the outer layer tube is not cracked or broken, or before the outer tube is plastically deformed. It is said that they are fixed to each other in a state where they cannot slide and take different behaviors.

  On the other hand, when the coil is covered with an outer layer tube and heated, or the adhesive is introduced between the coil layer and the outer layer tube, the outer surface of the coil and the inner surface of the outer layer tube are fixed. When the medical tube is pulled and stretched, the outer tube portion fixed to the outer surface of the coil is pulled together with the coil, and only the outer tube located between the coil strands is locally stretched. And the tensile elongation decreases significantly. When operating a catheter in a clinical setting, a certain degree of tensile strength and tensile elongation is required for a medical tube used for the catheter in order to safely remove the catheter when it is caught in the body. The If the tensile strength is low, there is a risk of breaking immediately. Even if the tensile strength is high, if the tensile elongation is low, it may not be able to withstand rapid removal. Further, in the method of introducing an adhesive between the coil and the outer layer tube, for the purpose of preventing the adhesive from spilling into the lumen of the medical tube, the inner layer is present, or the coil winding shape is described later. The structure is limited.

  On the other hand, in the medical tube of the present invention, when the medical tube is pulled and stretched, the outer surface of the coil and the inner surface of the outer tube are slidably contacted and fixed. In addition, it becomes possible to receive tensile stress in the entire outer layer tube, and it is prevented from being stretched locally at a specific part of the outer layer tube, and is thin, flexible, and excellent in kink resistance and tensile strength ( As in the other examples of the present application, even when the outer layer tube and the coil layer have portions that are directly or indirectly fixed to each other (for example, using a separate adhesive or the like). In the case where the ends are fixed), the outer tube is prevented from being locally stretched in relation to each winding of the coil, and the present invention is also intended for those that do not contradict the gist of the present invention. Medical chi Are intended to be included in the over drive.). In addition, since there is no need to use an adhesive, the special structure is not limited for the purpose of preventing the adhesive from spilling into the lumen of the medical tube. For example, the winding shape of the coil is not limited. It doesn't matter whether it exists or not.

  Further, since the medical tube of the present invention is produced without subjecting the outer layer tube to processing such as heating, the outer layer tube is the same as the original tube regardless of the winding shape of the coil layer inside or the shape of the coil wire. Molding can be performed while maintaining a uniform thickness, and the outer layer tube can ensure the tensile strength and tensile elongation as a single-layer resin tube. FIG. 2 shows a partially enlarged view of a cross section of the medical tube according to the present invention. The outer tube 102 has a uniform thickness regardless of the presence or absence of a coil layer disposed inside. In particular, the thickness of the outer tube 102 is also maintained at 104A that contacts the coil wire end. On the other hand, when the outer tube is heated at a high molding temperature as in the past, depending on the winding shape of the coil layer and the shape of the coil wire, the thickness of the outer tube varies at the end of the coil wire. There is a problem that the elongation decreases locally. FIG. 3 shows a partially enlarged view of the cross section of the medical tube in this case, but the thickness of the outer tube 102 is locally reduced. In particular, the thickness of the outer layer tube 102 is reduced at 104B in contact with the coil wire end. This is because, when the molding is performed at a high temperature, the resin melts so that the resin at the coil wire end portion easily flows to a portion without the coil wire, and the thickness of the outer tube is locally reduced at the coil strand end portion 104B. This phenomenon is particularly likely to occur when the coil layer winding shape or coil wire shape is pitch winding or flat wire, which will be described later. In order to secure tensile strength and tensile elongation in the conventional method, the outer layer tube It was necessary to increase the thickness of the wall. However, increasing the outer diameter to increase the wall thickness increases invasiveness, making peripheral treatment of thinner body lumens impossible, and reducing the inner diameter reduces drug injectability, thrombus aspiration, and other catheters. There arises a problem that remarkably impairs the deliverability of the. Therefore, it has been difficult for the conventional technology to produce a thin, flexible, medical tube excellent in kink resistance and tensile strength as intended in the present invention.

  There is no particular limitation on the wire shape, wire size, winding shape, etc. of the coil layer used in the medical tube according to the present invention. The wire shape may be a general round wire or a flat wire to be described later, and the winding shape may also be a close winding or pitch winding to be described later, and these may differ depending on the portion of the medical tube. . However, as with the proximal shaft of the catheter, in addition to the kink resistance and tensile strength of the shaft, which is a characteristic of the medical tube according to the present invention, when a certain degree of bending rigidity and longitudinal pushing force are required, The strand shape is preferably a flat wire, and or alternatively, the winding shape is preferably tight winding. A flat wire is not a circular cross section, but a shape having a thickness and a width, and is generally obtained by rolling a strand having a circular cross section called a round wire. The flat wire referred to in the present invention includes a wire called a flat wire generally called a flat wire, whose upper and lower surfaces are generally parallel and whose both ends are rounded, and a flat wire whose cross section is generally rectangular. Close-contact winding is a winding shape in which adjacent strands are wound so that they are at least close to or in contact with each other. As described above, the coil layer is configured by a tightly wound winding made of a flat wire, so that the bending rigidity of the medical tube is increased in spite of the thin shaft, and the longitudinal direction of the medical tube is increased. The pushing force of becomes stronger. Further, from the viewpoint of further increasing the rigidity and the pushing force of the shaft, it is preferable that a compression force (a force generally called initial tension) is provided between adjacent strands in the longitudinal direction of the coil. By having the initial tension as strong as possible while the adjacent strands are not displaced, the bending rigidity and pushing force of the shaft can be further improved. The proximal shaft of the catheter may be bent to a very high bend during clinical site surgery. In the case of the medical tube according to the present invention, when the medical tube having the coiled coil layer described above is used for the proximal shaft of the catheter, the shaft is bent at such a high degree of bending. Since the coil layer and the outer layer tube are constrained to each other but are not fixed, they can behave differently. Therefore, the medical tube according to the present invention, in particular, the wire shape is a flat wire, the wound shape is a close winding, and the coil has a compression force (initial tension) in the longitudinal direction of the coil between adjacent wires. It is preferable to use one having one or more characteristics selected from those currently used for the proximal shaft of a catheter that may be bent at a very high bend during a surgical operation in the clinical field (particularly these Those with all the characteristics are preferred.)

  On the other hand, if the outer surface of the coil and the inner surface of the outer layer tube are firmly fixed as in the prior art, only the outer layer tube between the coil strands is stretched locally when the shaft is bent to a high degree of bending. Therefore, the same problem as the tensile strength occurs. In order to prevent such a phenomenon from occurring, it is necessary to increase the thickness of the outer layer tube. In this case, the above-mentioned problem occurs, and further, the outer layer tube becomes kink by increasing the thickness of the outer layer tube. When the force is increased, the coil layer is kinked, and there is a problem that the operation cannot be performed continuously.

  In addition, there has been a tube in which the outer surface of the coil and the inner surface of the outer layer tube are hardly in contact with each other simply by placing the coil in the outer layer tube. Therefore, the coil is displaced, bent, overlapped, and the like. In such a state, a change occurs in the inner and outer diameters of the shaft, or the shaft is kinked, so that the operation cannot be continued.

  When the flexibility of the shaft is required in addition to the kink resistance and tensile strength of the shaft, which is a characteristic of the medical tube according to the present invention, such as the distal shaft of the catheter, the winding shape is pitch winding. Is preferred. The pitch winding is a winding shape wound so that there is a gap between adjacent strands. In particular, regarding the length in the longitudinal direction of the medical tube, it is preferable that the gap between the coil wires is the same as or longer than the width of the coil wires. With such a structure, a shaft that is more flexible and excellent in kink resistance can be realized. In addition, the pitch here means the length in the longitudinal direction of one point (360 degrees) apart in the circumferential direction along one wire (one point) of the coil wire (FIG. 1). And exemplified as A). More specifically, the sum of the width of the strands in the longitudinal direction and the gap between the strands is the pitch. Therefore, in the present invention, “the gap between the coil wires is equal to or longer than the width of the coil wire” means that the pitch is 2 t or more when the width of the wire is t. Indicates that Thus, in the case of the distal end shaft of the catheter having the coil layer of the pitch winding, the conventional method has a problem that the thickness of the outer tube as described above varies, and the tensile strength and the tensile elongation are remarkably lowered. It was easy to occur. However, increasing the thickness of the outer tube to ensure tensile strength increases the outer diameter of the distal shaft of the catheter that is inserted into the distal end of the body lumen, and also increases the flexibility of the distal shaft of the catheter. It will be lost and the insertability will be significantly reduced. However, in the medical tube according to the present invention, the outer surface of the coil and the inner surface of the outer layer tube are contacted and fixed in a slidable state, so that they are not stretched locally at a specific portion of the outer layer tube, In addition, since no special heating or the like is required for the outer tube at the time of manufacture, the outer tube can easily maintain a uniform thickness, and the tensile strength and tensile elongation can be secured. While maintaining, it becomes possible to make a structure having kink resistance, and even when inserted into the periphery of a very bent body lumen, the shaft can be smoothly inserted without kinking. In addition, it is possible to maintain the lumen of the shaft even when the distal shaft of the catheter is very bent, so that it is possible to maintain the drug injectability, thrombus aspiration, and other catheter delivery properties. it can.

  As the material of the wire constituting the coil layer, various materials such as metal and resin can be used, but in particular, stainless steel or a material having high radiopacity, for example, metal such as tungsten, platinum, iridium, and gold. It is preferable. Of these, stainless steel spring steel, tungsten, etc., which have high tensile elastic modulus of the strands, are particularly preferable. By using such an element wire, it is possible to produce a medical tube that is thinner and has improved kink resistance.

  Examples of the material of the outer tube include nylons 6, nylon 66, nylon 12, polyamides such as polyamide elastomer, olefins such as polyethylene, polypropylene, polymethyl methacrylate, and modified polyolefin, polyethylene terephthalate, polybutylene terephthalate, polyester elastomer, etc. Polyesters, polyurethanes, polyurethane elastomers, polyether ether ketones, polymer blends, polymer alloys, and the like. The resin material may contain various additives such as a contrast agent, a plasticizer, a reinforcing agent, and a pigment in addition to the polymerization aid used at the time of polymerization. Of these resins, thermoplastic elastomers that can be easily bonded to other tubes are preferable, and polyamide elastomers and polyurethane elastomers that have high toughness at the time of high bending are more preferable. Moreover, it is preferable to have a 2nd outer layer on the outer side of an outer layer tube, and it is still more preferable that melting | fusing point of a 2nd outer layer is lower than melting | fusing point of an outer layer tube. By heating at a temperature higher than the melting point of the second outer layer and lower than the melting point of the outer layer tube, it is possible to melt only the second outer layer and join another tube to the outer surface of the medical tube by welding or the like. Thus, it is easy to apply the medical tube of the present invention to various shapes of medical assemblies and catheters. In addition, from the viewpoint of ease of manufacture, before the outer layer tube and the coil are slidably contacted and fixed, the outer layer tube has a shape of a two-layer tube in which the second outer layer is coated on the outside. Is preferred.

  Moreover, it is preferable that the outer layer tube and the coil layer are in close contact with each other in approximately half or more of the circumferential length in the radial cross section of the medical tube. In a tube where the range of close contact is less than half, when the coil is highly bent, more than half of the radial cross-section of the coil is bent in a free state, which may cause misalignment, bending, or overlapping of the coil. . In such a state, a change occurs in the inner and outer diameters of the shaft, or the shaft is kinked, so that the operation cannot be continued. By being in close contact with the half or more, it is possible to prevent the coil from being in such a state, and it is possible to continue the operation. More preferably, the outer layer tube and the coil layer are slidably in contact with each other over substantially the entire circumference in the radial cross section. As a result, it is possible to further prevent the coil layer from being displaced, broken, or overlapped, and to stabilize and improve the kink resistance.

  In the present invention, the coil is stretched and / or twisted to reduce the diameter and inserted into the outer layer tube, and the stretching and / or twist is released to release the diameter, thereby sliding the outer layer tube and the coil. It is possible to produce medical tubes that are fixed in contact in a movable state. In addition, it is preferable that the direction which adds a twist is a direction which adds a twist in the same direction as the winding direction of a coil. By using such a manufacturing method, the outer layer tube or coil used as a raw material for the medical tube may be produced by any method, and a core material, a heating device, etc. that are necessary in the conventional method This facility is also unnecessary, and an excellent medical tube can be easily produced at a very low cost. For example, the outer layer tube can be produced at low cost by ordinary extrusion without using a special process, and the aforementioned two-layer tube having the second outer layer is used as the outer layer tube. It will be very easy to do. Also, the tube material used for the outer tube is not particularly limited as long as it can be molded. When a medical tube is incorporated in a catheter or the like and joined to another member, it is matched with the other member. By selecting the material, it is possible to freely select a joining method such as welding or adhesion. Furthermore, since it becomes possible to produce a thin tube that maintains the original flexibility of the material, it is possible to produce a very thin and flexible medical tube. As for the coil to be prepared, it is possible to use a coil produced by a normal method that does not use a special process (for example, a method of winding around a core material).

  In addition, about the point which cancels | stretches and / or twists and cancels diameter reduction, it is not necessary for the prepared coil to completely return in an outer layer tube, and the force which is extending and diameter-reducing a coil is excluded. By doing so, the outer layer tube and the coil may be contact-fixed in a slidable state. That is, the pitch and outer diameter of the prepared coil and the coil layer of the medical tube may be the same or different. Prepare the coil The outer diameter of the coil in the first step is D1, the pitch is A1, the outer diameter of the coil in the second step, which is reduced by stretching and / or twisting, is D2, the pitch is A2, and the outer layer When the outer diameter of the coil in the third step, which is inserted into the tube and stretched and / or untwisted to release the diameter reduction, is D3 and the pitch is A3, D1 ≧ D3> D2, A1 ≦ A3 <A2 A relationship is desirable. In addition, the medical tube which has a coil layer of the same pitch as the pitch of the prepared coil is producible by setting the outer diameter of the prepared coil and the internal diameter of a medical tube to the same dimension. In this case, since the coil needs to return to the shape of the first step, it is necessary not to cause plastic deformation of the coil in the second step. When manufacturing a medical tube in which the closely wound coil is slidably contacted with the outer layer tube, this method is used to prepare the closely wound coil so that the outer diameter of the coil matches the outer diameter of the outer layer tube. It becomes possible to produce it. On the other hand, by preparing a coil with an outer diameter larger than the inner diameter of the outer layer tube, the pitch of the coil layer becomes larger than the prepared coil (because the outer diameter of the coil is suppressed by the outer layer tube, the prepared coil is completely Will not return). By such a method, the coil and the outer layer tube can be firmly and reliably adhered, and the kink resistance can be further improved. In this case, the outer diameter of the coil only needs to return to the inner diameter of the outer tube, so there is no problem even if plastic deformation of the smaller coil occurs. This method is particularly useful when producing a medical tube having the above-described pitch-wound coil layer. By controlling the pitch of the coil to be prepared, the inner diameter of the outer layer tube, the outer diameter of the coil to be prepared, the amount of extension and the diameter reduction of the coil, it becomes possible to create a medical tube having a desired pitch. By adopting such a method, a medical tube in which the pitch-wound coil and the outer layer tube are more strongly and surely adhered can be stably produced at an arbitrary pitch. At this time, it is preferable to reduce the diameter by adding a twist to the coil, so that the amount of reduction can be finely adjusted by the number of twists.

  Moreover, it is preferable to include the 4th process which applies external force from the both ends of a coil, after canceling | stretching and diameter reduction of a coil. When producing a medical tube using a tightly wound coil, it is necessary to match the outer diameter of the prepared coil with the inner diameter of the outer layer tube as described above, but by applying external force (especially compressive stress) from both ends of the coil. The outer diameter of the prepared coil can be made larger than the inner diameter of the outer layer tube. For example, a tightly wound coil is prepared, and the coil is extended and reduced in diameter and inserted into an outer tube having an inner diameter slightly smaller than the outer diameter. When the extension and diameter reduction are released, the pitch-wound coil having a very small pitch is in close contact with the outer tube, but after that, by applying external force from the end of the coil, the tight-wound coil is in close contact with the outer tube. It becomes possible to be in a state. With such a method, when producing a medical tube using a tightly wound coil, it is possible to more stably produce a medical tube in which the tightly wound coil and the outer layer tube are firmly and securely adhered. Become. Also, when the rigidity and pushing force of the shaft is required, such as the proximal shaft of the catheter, the compression force can be improved in the longitudinal direction of the coil between adjacent strands by such a method. It is possible to improve the bending rigidity and pushing force of the. In this case, the method of applying an external force is not particularly limited, and a core material having an outer diameter equivalent to the inner diameter of the outer layer tube or a core material having an outer diameter equivalent to the inner diameter of the coil may be pushed in from both sides by a pipe. Alternatively, both ends of the coil may be fixed by a pipe or a pipe, and the coil may be pushed in while being twisted. Thus, when applying external force from both ends of the coil, it is preferable to insert a core material close to the inner diameter of the coil inside the coil so as not to disturb the coil. In addition to the method of applying external force, a method of returning to close winding using the restoring force of the close winding coil used as a raw material, for example, after the third step, applying ultrasonic waves to this to make close winding Is possible.

  In a general catheter, the distal shaft is inserted as far as the living body lumen, particularly the periphery of the blood vessel, so that it is as thin and flexible as possible and requires kink resistance and tensile strength. On the other hand, in order to reach the distal end of the catheter to the distal end, the proximal shaft often requires a certain degree of bending rigidity and pushing force in the longitudinal direction in addition to the kink resistance and tensile strength of the shaft. Therefore, it is preferable that the distal end side shaft of the catheter is made of a medical tube having the pitch winding coil of the present invention and the proximal side shaft is made of a medical tube having the close winding coil of the present invention. After producing each shaft, it is possible to produce a catheter by joining by a method such as adhesion or welding, but from the viewpoint of ease of manufacturing and cost reduction, the inner diameter differs between the distal end side and the proximal side. It is more preferable to prepare an outer layer tube and produce a coil layer with one coil. As described above, the pitch in the coil layer of the medical tube can be determined by the pitch and outer diameter of the coil to be prepared and the inner diameter of the outer tube. When the inner diameter of the outer layer tube is smaller than the outer diameter of the coil to be prepared, the pitch in the coil layer of the medical tube is larger than the pitch of the coil to be prepared, and the outer diameter of the prepared coil is the same as the inner diameter of the outer layer tube In addition, the pitch of the coil layer of the medical tube is the same as the pitch of the coil to be prepared.

  For example, a tightly wound coil having an outer diameter D4 and an outer tube having an inner diameter of the proximal shaft portion D4 and an inner diameter of the distal shaft portion D5 smaller than D4 are prepared, and the outer diameter of the tightly wound coil is larger than D5. The outer layer tube is stretched and reduced in diameter so as to be reduced, and is disposed so as to penetrate from the distal end side to the proximal side of the outer tube. Thereafter, by releasing the extension and diameter reduction of the coil, it is possible to produce a medical tube having a tightly wound coil on the proximal shaft portion and a medical tube having a pitch wound coil on the distal shaft. With such a method, it is possible to produce a shaft with a kink resistance and a tensile strength as well as a thin and flexible tip shaft and a bending shaft and a pushing force in the longitudinal direction on the proximal shaft in a simple process. Become. Not limited to this example, in the method for manufacturing a medical tube of the present invention, one prepared coil (including a close-wound coil is included) by changing the inner diameter of the outer tube in two stages or more. From the above, a medical tube having a plurality of coil layers with different pitches can be produced. In the conventional method, in order to produce a medical tube having coil layers with different pitches, it is necessary to produce coils suitable for each. In that case, when joining these medical tubes, it is necessary to join the coils together for safety reasons, but if they are joined by methods such as bonding, welding, and joining by resin, the joining strength is weak and breaks during the procedure. As a result, there are problems such as dropping off, the shaft of the joint portion becoming hard, and the insertion property of the catheter is lowered. In addition, it is not impossible to prepare a continuous coil with varying pitch and outer diameter, but it is difficult and stable to produce such a coil stably with the technology of those skilled in the art. However, there is a problem that it is very expensive. According to the manufacturing method of the present invention, the coil to be prepared may be a normal coil whose pitch and outer diameter do not change, and it is not necessary to join the coils to each other. Therefore, it is possible to produce a medical tube very inexpensively and easily. The outer layer tube having a different inner diameter may be joined by bonding or welding tubes having different inner diameters, or may be integrally formed by extrusion. The outer diameter may be changed similarly to the inner diameter, and the outer diameter may be constant regardless of the inner diameter.

  In addition, the present invention allows the outer layer tube to slide on the coil by disposing the outer layer tube on a coil produced by winding the core wire while applying tension to the element wire and releasing the tension. It is related with the manufacturing method of the medical tube characterized by carrying out contact fixation in a state. According to such a manufacturing method, it is possible to easily provide a thin-walled, flexible, medical tube excellent in kink resistance and tensile strength at the same time as producing a coil without using a special structure or manufacturing method. It becomes possible. By applying tension to the core wire and winding it around the core wire, a force in a direction in which the outer diameter increases is stored in the coil. While maintaining this state, the outer layer tube is placed outside the coil and the tension is released to increase the outer diameter of the coil, so that the coil and the outer layer tube can be slidably contacted and fixed. Become. By adjusting the tension when winding around the core wire, the outer diameter of the core wire, the pitch of the coil in the wound state, the inner diameter of the outer tube, etc., the coil pitch as a medical tube and the initial tension of the closely wound coil can be arbitrarily set Can be determined.

  The tensile elongation and tensile strength referred to in the present invention refer to the tensile elongation at break and tensile breaking strength. In the present invention, the maximum displacement and load when a portion other than the coil of the medical tube is broken. Point. This is because the tensile length at which the coil breaks is very large, the breaking elongation and breaking strength of the coil are less important in the medical tube, and the breaking elongation and breaking strength of parts other than the coil are important in the medical tube. Is high.

  The medical tube according to the present invention is thin, flexible, excellent in kink resistance and tensile strength, and can be easily joined to other tubes and other members, so it can be widely applied to medical devices such as catheters. is there. The present invention can be applied not only to the proximal shaft and the distal shaft of the catheter as described above but also to a medical device using a guide wire lumen or other tube. For example, when used as a shaft of a balloon catheter, a thin shaft can be used, so that the lumen can be widened and the deflation time of the balloon can be shortened. When used as the shaft of a catheter for drug injection, a thin shaft can be used, so that the lumen can be widened and the amount of drug injected can be increased. When used as a catheter shaft for a thrombus suction catheter, a thin shaft can be used, so that the lumen can be widened and the amount of thrombus sucked can be increased. When used as a delivery catheter shaft such as other catheters, a thin-walled shaft allows a wider lumen and delivery of a larger catheter or the like. In addition, in these catheters, when the lumen is the same as the conventional one, the outer diameter of the catheter can be reduced, enabling a less invasive treatment and a treatment in a thinner peripheral body lumen. .

  EXAMPLES Hereinafter, although this invention is demonstrated in detail according to an Example, this invention is not limited to a following example. The following examples show a comparison of kink resistance, tensile strength, and tensile elongation, and do not describe the possibility of thinning and ease of manufacture.

Example 1
The coil layer used was a tightly wound coil having an inner diameter of 1.02 mm and a length of 300 mm made of a stainless steel flat wire (thickness: 0.10 mm, width: 0.20 mm). The outer layer tube is made of polyurethane elastomer (Shore D hardness 68D, melting point 182 ° C.) with an inner diameter of 1.21 mm and an outer diameter of 1.35 mm by extrusion molding by ordinary pulling air into the lumen using an extruder. Was used.

  The prepared coil was stretched and twisted to reduce the outer diameter to 1.20 mm or less and inserted into the outer layer tube. Thereafter, the extension and diameter reduction of the coil were released to obtain a medical tube having an inner diameter of 1.01 mm, an outer diameter of 1.35 mm, and a gap between the strands of 0.05 mm (pitch 0.25 mm).

(Example 2)
The coil layer and the outer layer tube were the same as in Example 1.

  The prepared coil was stretched and twisted to reduce the outer diameter to 1.20 mm or less and inserted into the outer layer tube. Thereafter, a tube having an inner diameter of 1.01 mm, an outer diameter of 1.35 mm, and a gap between the strands of 0.05 mm (pitch of 0.25 mm) obtained by releasing the extension and reduction of the coil is obtained, and a diameter is obtained in the lumen. A stainless steel core material having a length of 1.00 mm and a length of 400 mm was inserted. In addition, a stainless steel pipe having an inner diameter of 1.02 mm and an outer diameter of 1.18 mm is inserted into the gap between the outer tube and the stainless steel core, and an external force is applied from both ends of the coil to reduce the coil pitch. A medical tube having a diameter of 1.35 mm and a closely wound coil (gap between the strands of 0 mm) was obtained.

Example 3
The coil layer was the same as in Example 1. The outer tube is a tube made of polyamide elastomer (Shore D hardness 72D, melting point 176 ° C.) produced by extrusion molding by ordinary pulling in air into an inner cavity using an extruder, an inner diameter of 1.21 mm, an outer diameter of 1 A 35 mm proximal tube and an inner tube with an inner diameter of 1.19 mm and an outer tube with an outer diameter of 1.29 mm were joined to each other with an adhesive to produce a tube with a varying inner diameter.

  Stretching and twisting the prepared coil to reduce the outer diameter to 1.18 mm or less, inserting it into the outer layer tube, and joining the central portion in the axial direction of the coil between the distal tube and the proximal tube Placed in the department. Thereafter, the extension and diameter reduction of the coil are released, the hand side has an inner diameter of 1.01 mm, the outer diameter is 1.35 mm, the gap between the strands is 0.05 mm (pitch 0.25 mm), the tip side is the inner diameter of 0.99 mm, the outer diameter A medical tube of 1.29 mm and a gap between the strands of 0.14 mm (pitch 0.34 mm) was obtained.

Example 4
The coil layer and the outer layer tube were the same as in Example 1.

  Stretching and twisting the prepared coil to reduce the outer diameter to 1.18 mm or less, inserting it into the outer layer tube, and joining the central portion in the axial direction of the coil between the distal tube and the proximal tube Placed in the department. Thereafter, the extension and diameter reduction of the coil are released, the hand side has an inner diameter of 1.01 mm, the outer diameter is 1.35 mm, the gap between the strands is 0.05 mm (pitch 0.25 mm), the tip side is the inner diameter of 0.99 mm, the outer diameter A tube having 1.29 mm and a gap between strands of 0.14 mm (pitch 0.34 mm) was obtained, and a stainless steel core material having a diameter of 1.00 mm and a length of 400 mm was inserted into the proximal lumen. Also, a stainless steel pipe having an inner diameter of 1.02 mm and an outer diameter of 1.18 mm is inserted into the gap between the outer tube and the stainless steel core, and an external force is applied from one end of the proximal coil to reduce the coil pitch. .01mm, outer diameter 1.35mm, closely wound coil (gap between strands 0mm), tip side is 0.99mm inner diameter, outer diameter 1.29mm, gap between strands 0.14mm (pitch 0.34mm) A tube was obtained.

(Example 5)
The coil layer consists of a stainless steel flat wire (thickness 0.02 mm, width 0.10 mm), an inner diameter of 1.00 mm, a gap between the strands of 0.05 mm (pitch 0.15 mm), and a length of 300 mm. A coil was used. Polyamide whose outer layer (second outer layer) has a thickness of 0.02 mm is obtained by extruding the outer layer tube and the second outer layer by using an extruder to extrude the two-layer tube by ordinary pulling air into the lumen. Made of elastomer (Shore D hardness 35D, melting point 152 ° C.), inner layer (outer layer tube) made of polyamide elastomer (Shore D hardness 70D, melting point 174 ° C.) with an inner diameter of 1.03 mm, outer diameter 1 A 17 mm bilayer tube was made and used.

  The produced coil was stretched and twisted to reduce the outer diameter to 1.02 mm or less and inserted into the outer layer tube. Thereafter, the extension and diameter reduction of the coil were released to obtain a medical tube having an inner diameter of 0.99 mm, an outer diameter of 1.17 mm, and a gap between the strands of 0.10 mm (pitch 0.20 mm).

  A stainless core material having a diameter of 0.98 mm and a length of 400 mm is inserted into the lumen of the produced medical tube (hereinafter referred to as the first tube), and the outer surface within a range of 150 mm from one end of the medical tube containing the stainless steel core material. And a second tube (inner diameter 0.41 mm, outer diameter 0.56 mm, length 150 mm) made of polyamide elastomer (Shore D hardness 55D, melting point 168 ° C.) with a stainless steel core of 0.40 mm in diameter inserted in parallel. A heat shrinkable tube (made of polyolefin, shrinkage temperature of 115 ° C or higher, shrinkage rate of 40% or higher, inner diameter of about 2.0 mm) is covered so that both the medical tube containing the stainless steel core and the second tube are inserted. Heated in an oven set at 170 ° C. for 2 minutes. After taking out from the oven, the heat shrinkable tube is peeled off, the stainless steel core material with a diameter of 1.00 mm and the stainless steel core material with a diameter of 0.40 mm are taken out, and the portion where the second tube is welded in parallel is 150 mm. A medical assembly consisting only of 150 mm was obtained.

(Example 6)
The outer layer tube was the same as in Example 1.

  A stainless steel flat wire (thickness: 0.10 mm, width: 0.20 mm) was wound around a core wire having an outer diameter of 0.90 mm using a coiling machine to produce a tightly wound coil in a tensioned state.

  The produced coil was inserted inside the outer layer tube, and the tension of the coil was released to obtain a medical tube having an inner diameter of 1.01 mm, an outer diameter of 1.35 mm, and a closely wound coil (gap between the strands of 0 mm).

(Comparative Example 1)
The coil layer used was a tightly wound coil made of a stainless steel flat wire (thickness 0.10 mm, width 0.20 mm) having an inner diameter of 1.00 mm and a length of 300 mm. The outer layer tube is made of polyurethane elastomer (Shore D hardness 68D, melting point 182 ° C.) with an inner diameter of 1.25 mm and an outer diameter of 1.39 mm by extrusion molding by ordinary pulling air into the lumen using an extruder. Was used.

  A stainless core material having a diameter of 0.98 mm and a length of 400 mm was inserted into the lumen of the manufactured coil, and this was inserted inside the outer layer tube. Further, a heat shrinkable tube (made of polyolefin, shrinkage temperature of 115 ° C. or higher, shrinkage rate of 40% or higher, inner diameter of about 1.5 mm) was covered over the entire length of the outer layer tube, and heated for 2 minutes in an oven set at 200 ° C. . After taking out from the oven, the heat-shrinkable tube was peeled off and the stainless steel core material was taken out to obtain a medical tube having an inner diameter of 1.00 mm and an outer diameter of 1.35 mm.

(Comparative Example 2)
The coil layer was the same as in Comparative Example 1. The outer layer tube is a tube made of polyamide elastomer (Shore D hardness 72D, melting point 176 ° C.) having an inner diameter of 1.25 mm and an outer diameter of 1.39 mm by extrusion molding by ordinary pulling in air into the lumen using an extruder. Was used.

  A stainless core material having a diameter of 0.98 mm and a length of 400 mm was inserted into the lumen of the manufactured coil, and this was inserted inside the outer layer tube. Further, a heat-shrinkable tube (made of polyolefin, shrinkage temperature of 115 ° C. or higher, shrinkage of 40% or higher, inner diameter of about 1.5 mm) was covered over the entire length of the outer layer tube and heated in an oven set at 200 ° C. for 2 minutes. . After taking out from the oven, the heat-shrinkable tube was peeled off and the stainless steel core material was taken out to obtain a medical tube having an inner diameter of 1.00 mm and an outer diameter of 1.35 mm.

(Comparative Example 3)
The coil layer and the outer layer tube were the same as in Example 5.

  A stainless core material having a diameter of 0.98 mm and a length of 400 mm was inserted into the lumen of the manufactured coil, and this was inserted inside the outer layer tube. Further, a heat-shrinkable tube (made of polyolefin, shrinkage temperature of 115 ° C. or higher, shrinkage of 40% or higher, inner diameter of about 1.5 mm) was covered over the entire length of the outer layer tube and heated in an oven set at 200 ° C. for 2 minutes. . After taking out from the oven, the heat-shrinkable tube was peeled off and the stainless steel core material was taken out to obtain a medical tube having an inner diameter of 1.00 mm and an outer diameter of 1.18 mm.

(Comparative Example 4)
The coil layer was the same as in Comparative Example 1. The outer layer tube was the same as in Example 1.

  Insert a stainless steel core with a diameter of 0.98 mm and a length of 400 mm into the lumen of the coil, and insert it inside the outer tube, taking care not to disturb the coil. A 35 mm medical tube was obtained.

(Comparative Example 5)
The outer layer tube is a tube made of polyamide elastomer (Shore D hardness 72D, melting point 176 ° C.) having an inner diameter of 1.21 mm and an outer diameter of 1.35 mm by extrusion molding by ordinary pulling in air into the lumen using an extruder. Was used. Except for the outer layer tube, it was the same as Comparative Example 4.

(Evaluation)
“Kink resistance test” in which a medical tube is held at two locations, and the tube is bent by approaching the held portion, as well as a catheter operated at a clinical site, and a catheter etc. at a clinical site Similarly to the movement of pulling, two types of evaluations were performed: a “tensile test” in which the medical tube was held at two locations and the held portion was pulled for evaluation. For the medical tubes produced in Examples 1 to 6 and Comparative Examples 1 to 5, two types of evaluations were performed, but for Examples 3 to 4, two locations on the hand side and the tip side, and for Example 5, Evaluation was similarly performed about the part which joined the 2nd tube.

(Kink resistance test)
Keep the medical tube in a straight state, hold two points separated by a certain distance in the longitudinal direction with your left and right hands, slowly bring both hands close to a straight line until the held distance is 10 mm The presence or absence of kink was observed when the tube was bent close to it. The kink as used herein refers to a state in which the outer tube is cracked or broken, or a large plastic deformation (elongation, etc.) occurs. In many cases, the state does not return to the original medical tube state even if the outer tube is returned to a straight line. The initial holding distance was set to 70 mm that would be bent to a very high bend when the test was conducted to the end. As the evaluation results, the kink resistance of the medical tube was evaluated with ◯ when not kinking and x when kinking.

  The results of the kink resistance test are shown in Table 1.

  About Examples 1-6, it did not kink to the last, the crushing of the lumen | bore, the crack of an outer layer, and the disorder | damage | failure of a coil did not generate | occur | produce, but showed favorable kink resistance. In addition, in Examples 3 to 4, both the proximal side and the distal end side exhibit good kink resistance, and in Example 5, similarly to the medical assembly joined with the second tube, good kink resistance. Showed sex.

  About Comparative Examples 1-2, when it approached to the distance of 20 mm, the outer-layer tube cracked and kinked.

  For Comparative Example 3, the outer tube was stretched and kinked at the gap between the coil strands when approaching to a distance of 20 mm. The stretched portion of the outer tube remains in a slack state even when the tube is returned to the straight shape, and the rigidity of the medical tube is extremely lowered and the outer diameter is increased.

  In Comparative Examples 4 to 5, in the test with a holding distance of 70 mm, the outer layer tube kinked when approached to a distance of 40 mm, and coil displacement and overlap occurred, resulting in kinking. Even if it was returned to the straight line, the deviation and overlap of the coils were not resolved.

(Tensile test)
The medical tube was subjected to a tensile test using a tensile and compression tester (Shimadzu Corp.) under the conditions of a distance between chucks of 50 mm and a tensile speed of 1000 mm / min to evaluate the tensile strength and tensile elongation. The tensile strength and the tensile elongation were the maximum load and displacement when a portion other than the coil of the medical tube composed of the coil layer was broken. The tensile elongation is represented by (displacement at break / distance between chucks) × 100 [%]. Here, the displacement at the time of breakage is the distance at the time of breakage when the chucked state is 0 mm, and is the distance that the medical tube is actually stretched.

  Table 2 shows the results of the tensile test.

  About the tensile strength of Examples 1-6, although there is a difference depending on the hardness of the resin, the thickness of the outer tube, etc., it showed a sufficient tensile strength of 12-17N (the proximal side and the distal end side of Examples 3-4) including). Further, the tensile elongation was also 105 to 257%, which was twice as much as the initial state, although there was a difference as well as the tensile strength (including the proximal side and the distal end side of Examples 3 to 4). Regarding Example 5, the medical assembly in which the second tube was joined also showed a tensile strength of 13N, a tensile elongation of 127%, and a result almost similar to that of the medical tube.

  About the tensile strength of Comparative Examples 4-5, although there was a difference by the hardness of resin, the thickness of an outer layer tube, etc., 15-17N and sufficient tensile strength were shown. Further, the tensile elongation was 240 to 251%, which was twice as large as the initial state, although there was a difference as well as the tensile strength.

  The tensile strengths of Comparative Examples 1 to 3 were all broken at a low load of 5 to 9 N, although there were differences depending on the hardness of the resin and the thickness of the outer tube. As for the tensile elongation, Comparative Examples 1 and 2 showed 191 to 217%, which was twice as much as the initial state, but Comparative Example 3 was 40% and broke immediately after starting to stretch.

  From the above results, it was confirmed that Examples 1 to 6 could be used as a medical tube without being kinked even in a very bent state. In addition, the tensile strength and tensile elongation showed sufficient load and elongation, and it was confirmed that it can be used safely as a medical tube. Moreover, in Example 5, it was confirmed that it can be used safely as a medical assembly.

  About Comparative Examples 1-3, the crack and kink of the outer-layer tube generate | occur | produced in the state bent highly bent, and it was confirmed that it cannot be used as a medical tube. The tensile strength was also broken at a low load. In particular, it was confirmed that Comparative Example 3 was broken at a low elongation, and Comparative Examples 1 to 3 had safety problems when used as a medical tube.

  As for Comparative Examples 4 to 5, the tensile strength and the tensile elongation are simply resin tubes, so although sufficient load and elongation were exhibited, kinks occurred in the outer layer tube in a highly bent state, and the coil Further, it was confirmed that misalignment and overlap occurred, making it impossible to use as a medical tube.

101. Medical tube 102. Outer layer tube 103. Coil layer 104A. Coil strand end 104B. Coil wire end

Claims (6)

A method of manufacturing a medical tube having a coil layer inside an outer tube made of resin,
A first step of preparing a coil, a second step of inserting and / or twisting the coil into the outer layer tube as a reduced diameter, and stretching of the coil in the outer layer tube, And / or releasing the diameter reduction by untwisting, the third step of fixing the outer tube on the coil in a slidable state, and after releasing the extension and the diameter reduction of the coil, And a fourth step of applying an external force from both ends of the coil.   The method for manufacturing a medical tube according to claim 1, wherein an outer diameter of the coil in the first step is larger than an inner diameter of the outer layer tube.   The method for manufacturing a medical tube according to any one of claims 1 and 2, wherein the coil pitch of the coil prepared in the first step is constant.   The inner diameter of the outer tube is changed in at least two stages of a first inner diameter and a second inner diameter, and in the third step, the coil pitch in the outer tube of the first inner diameter and the second inner diameter are The method for manufacturing a medical tube according to any one of claims 1 to 3, wherein coil pitches in the outer tube are made different. 5. The method of manufacturing a medical tube according to claim 4 , wherein the coil in the outer layer tube having the first inner diameter is tightly wound, and the coil in the outer layer tube having the second inner diameter is pitch-turned.   The method for producing a medical tube according to any one of claims 1 to 5, further comprising a second outer layer made of a material having a melting point lower than that of the outer layer tube, outside the outer layer tube.

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