JP4851878B2 - Tubular knitted body for catheter reinforcement and catheter using the same - Google Patents

Description

  The present invention relates to a metallic cylindrical net used in combination with a resin material as a reinforcing member in a medical catheter, and more particularly, high strength and excellent insertion operability, and repeated fatigue resistance, The present invention relates to a cylindrical mesh body having non-magnetic characteristics that has buckling resistance and can reduce image distortion due to magnetic field interference and disturbance even in combination using MRI, CT scan, and the like, and a catheter using the same.

  For example, as shown in FIG. 6, the catheter inserted into the blood vessel includes a flexible long cylindrical tube body A, a handle portion B that fixes the tube body A on the proximal end side, and a tube body A. And various medical members and medicines are supplied to a specific site in the human body blood vessel through an inner hole c passing from the handle B to the soft chip C.

  This catheter is flexible and capable of transmitting torque of the handle B to the soft tip C and buckling so that it can smoothly enter the target site along the complicated and branched blood vessel. Along with operability such as no endurance deformation, there is also a demand for a narrow diameter blood vessel, for example, a diameter that can enter the peripheral part of the blood vessel.

  In addition, the catheter needs to have an internal passage that is wide enough not to interfere with the supply of medicines and the like, and has pressure resistance that can withstand injection pressure.

  For this reason, as shown in the figure, a tube body b in which a fine metal wire a is braided (braided) along the peripheral surface of the tube body A is embedded.

  There is a proposal that such a thin metal wire a for braiding braids increases the tensile strength, thereby thinning the catheter wall and imparting rigidity capable of preventing kinking without sacrificing flexibility (for example, patents). Reference 1). In addition, as a wire used for the cylindrical mesh body b, it has also been proposed to braid using an annealed stainless steel wire rolled into a flat strip having a width of 0.26 mm and a thickness of 0.06 mm. (For example, Patent Document 2). Further, Patent Document 3 proposes to use an austenitic stainless steel that is a flat wire processed in the same manner as Patent Document 2 as an embodiment and to which N and Nb are added as a composition.

Japanese Patent Laid-Open No. 7-194707 JP-A-8-317986 JP 2002-282366 A

  However, in the fine metal wires shown in the above-mentioned patent documents, when ordinary stainless steel wire is cold worked and work hardened, the rigidity of the material increases and it becomes structurally unstable, and the fatigue resistance is reduced. Not only does this adversely affect the small diameter workability and braiding workability. Conversely, if the degree of work hardening is small, torque transmission and buckling resistance are reduced due to insufficient strength, resulting in inferior operability during use, and it is also preferable from the standpoint of pressure resistance during chemical injection. hard.

  In addition, Patent Document 3 adds N and Nb as described above to improve torque and king resistance by increasing the strength to make the tube thinner, and to improve one end of such problems. Although the use of austenitic stainless steel is described, there is no consideration for improvement of nonmagnetic properties.

  By the way, in the medical field in recent years, a catheter is used together with an advanced diagnostic inspection apparatus such as an MRI or CT scan. These devices apply the fact that countless hydrogen nuclei (protons) in the body are small magnets to detect their arrangement using magnetic resonance. For this reason, those having magnetic characteristics are liable to cause image distortion due to magnetic field interference and disturbance.

  As described above, the catheter must be capable of accurately grasping the insertion state without causing distortion of the image and improving the handleability. For this purpose, the catheter made of the magnetic material has the problem. It cannot be solved.

  Accordingly, the present invention provides a catheter that can prevent the above-mentioned various problems due to magnetic phenomena, particularly as a tubular mesh body for reinforcing a catheter, having particularly high strength, excellent operability, resistance to repeated fatigue and buckling. An object is to provide a reinforcing tubular knitted body and a catheter using the same.

That is, the invention according to claim 1 of the present application is
A tubular mesh body for reinforcing a catheter, which is formed into a thin tube-shaped braid by braiding a strip-shaped thin wire pressed to a thickness of 50 μm or less and having a flat surface, The band-like thin wire is stainless steel, and the composition is C ≦ 0.06%, Si ≦ 0.80%, Mn: 3.00 to 18.00%, Ni: 2.00 to 13.00 in mass%. %, Cr: 15.00 to 25.00%, N: 0.10 to 0.80%, and the balance is composed of Fe and inevitable impurities, or the main part is Mo: It contains at least one of 0.40 to 3.50%, Cu: 0.08 to 0.80%, and the balance is composed of Fe and unavoidable impurities. ) Is 1500 to 3000 MPa, and the magnetic permeability at an environmental temperature of 20 ° C. is 1.01 or less. And wherein the Turkey which have a high strength non-magnetic properties.

  In the invention according to claim 2 of the present application, the stainless steel is mass%, and the main part is C: ≦ 0.03%, Si ≦ 0,50%, Mn: 5.00 to 8.00%, Ni: 8.00 to 12.00%, Cr: 19.00 to 23.00%, N: 0.30 to 0.60%, and Mo: 1.00 to 3.00%, Cu : At least one of 0.08 to 0.80%, and the balance: Fe and unavoidable impurities.

  In the invention according to claim 3 of the present application, the stainless steel is mass%, and the main part is C ≦ 0.06%, Si ≦ 0.50%, Mn: 12.00-17.00%, Ni: 2 0.00 to 5.00%, Cr: 16.00 to 20.00%, N: 0.30 to 0.60%, and Mo: 0.40 to 2.00%, Cu: 0.40 It is characterized in that it contains at least one kind of ˜0.70% and is composed of the balance: Fe and inevitable impurities.

  In the invention according to claim 4 of the present application, the inevitable impurities include at least one element of Nb, Ti, Al, O, and the content of the element is mass%, Nb: 0.020% or less, Ti: It is characterized by being 0.030% or less, Al: 0.010% or less, and O: 0.008% or less.

The invention according to claim 5 of the present invention is characterized in that the stainless steel satisfies the following relational expression in mass% of the element.
Ni + 1.05Mn + 12.6N = (18.0-25.0%)
≧ 0.65Cr + 12.6C

In the invention according to claim 6 of the present application, the strip-like thin wire is 20 μm or less in thickness by cold drawing after the solution heat treatment and cold rolling after the wire drawing, and 2 to 2 of the thickness. The invention according to claim 7 is characterized in that it has a width dimension of 10 times, and the invention according to claim 7 of the present application is such that the yield strength ratio {(τ / σ) between the tensile strength (σ) MPa and 0.2% yield strength (τ) MPa. × 100} is 85 to 98%.

  The invention according to claim 8 of the present application is characterized by having a tube body formed by arranging and encapsulating a resin material on the inner and outer surfaces of the cylindrical mesh body according to any one of claims 1 to 7. It is a catheter.

  In the invention according to claim 1 of the present application, the thin strip wire used for the cylindrical mesh body has a flat cross-sectional shape having a flat surface pressed to a thickness of 50 μm or less, and has a high strength characteristic of a tensile strength of 1500 to 3200 MPa. And an austenitic stainless steel with a specific composition added with high Mn and N, which has nonmagnetic properties with a magnetic permeability of 1.01 or less, and this is formed into a cylindrical tubular network (blade) by braiding. Therefore, it is easy to maintain the knitted rough shape, has high strength and excellent insertion operability, and has high fatigue characteristics and buckling resistance against bending and repetition. In addition, the stainless steel stabilizes the austenite phase by the composition with high Mn and N added in the austenite system, and has high strength and non-magnetism. Therefore, this stainless steel is used in combination with a magnetic resonance diagnostic apparatus such as MRI. Even in this case, the influence of magnetism can be suppressed and image disturbance can be prevented.

  In the inventions according to claims 2 and 3, the characteristics are further stabilized by the adjusted composition of the stainless steel, and in particular, the invention according to claim 2 can improve the corrosion resistance. According to the present invention, it is possible to further improve the elastic modulus and fatigue characteristics, and to provide a net body having more excellent buckling resistance.

  Furthermore, according to the inventions of claims 4 and 5, the generation of oxides such as Nb, Ti, Al, O and non-metallic inclusions is prevented, and the surface properties are excellent, and the austenite phase is stabilized to improve the characteristics. In addition, as a thin metal strip-like thin wire, a network for a catheter with repeated fatigue characteristics is made possible, and the nonmagnetic characteristics are further improved.

  In the invention of claim 6, the strip-like thin wire is a material that is once work-hardened by cold drawing after solution heat treatment, and is cold-rolled. It is possible to form a strip-like wire excellent in dimensional stability by preventing minute irregularities in the structure. Therefore, in the net body using this, the breakage due to repeated fatigue is prevented and a long-life cylindrical net body is obtained. As in the invention, when the ratio of the proof stress to the tensile strength is large, the elasticity as a cylindrical mesh body can be improved, and the net body is obtained with suppressed brittle fracture and shape change.

  Furthermore, in the invention according to claim 8, since the resin film material is disposed on the inner and outer surfaces of the cylindrical mesh body and encapsulated, the catheter using the cylindrical mesh body according to the above invention has its characteristics. Can be greatly improved.

  Hereinafter, the best mode of a tubular mesh body 1 for reinforcing a catheter according to the present invention (hereinafter also simply referred to as a tubular mesh body) will be described with reference to the drawings. The tubular mesh body 1 is used for the tube body A in the catheter 2 shown in FIG. 6, and is made long and flexible by arranging and encapsulating a resin film on the inner and outer surfaces of the tubular mesh body 1. The tube body A is formed. In FIG. 6, the catheter 2 includes the tube body A, a handle portion B for fixing the tube body A on the proximal end side, and a soft tip C disposed on the distal end side of the tube body A. Various medical members and medicines are supplied to a specific site in the human body blood vessel by the inner hole c passing from the part B to the soft chip C.

  As shown in FIG. 1, the cylindrical net 1 is formed by weaving strip-shaped thin wires 4 into a cylindrical shape, and the strip-shaped thin wires 4 are each formed in a flat plane 3 by, for example, cold rolling as shown in FIG. 2. 3 and a thickness t of 50 μm or less. When the thickness t of the strip-like thin wire 4 exceeds 50 μm, the thickness of the tube body A becomes large and lacks flexibility, and it is difficult to reduce the diameter of the cylindrical mesh body 1. . Therefore, the thickness t is preferably about 10 to 35 μm, more preferably about 15 to 30 μm.

  Further, the ratio (w / t) of the width w of the thin strip 4 to the thickness t is about 2 to 10 times, for example, the width w is about 0.1 to 2 mm. If w / t is excessively large, the yield of the rolling process is lowered and knitting becomes difficult.

  The strip-shaped thin wire 4 forms the cylindrical mesh body 1 by braiding the flat surfaces 3 and 3 in a cylindrical shape while maintaining a predetermined pitch p and gap g while alternately intersecting and intersecting in this example. Yes. The cylindrical net 1 is called a braid or a blade mesh, and is formed to have a thickness of, for example, an outer diameter of about 0.5 to 2 mm according to the specification of the catheter. The weaving process can be performed by a known braiding machine, a braider, or the like, and the band-like thin wire 4 is biased while being inclined at an inclination angle α with respect to the central axis 1A of the cylindrical net body 1. Thereby, torque transmission property and flexibility with respect to torsion are enhanced. As the woven structure, for example, an arbitrary structure such as a plain weave or a twill weave is selected, and depending on the purpose of use of the cylindrical net 1, together with the specifications of the strip thin wires 4, the pitch p, the number and the strip thin wires 4 A gap g and the like are set. Note that the pitch p, the gap g, and the like are measured in plan view on the central axis 1A of the cylindrical net body 1. The gap g is usually set to, for example, about 0.3 to 0.8 mm because the catheter is required to have sufficient flexibility and is integrally encapsulated by a resin material passing through the gap g. Further, the inclination angle α is set, for example, from 40 to 70 °, and the pitch p is set from the gap g, the inclination angle α, the width w of the strip-like thin wire 4 and the like.

  Further, the strip-like thin wire 4 of the cylindrical net 1 is made of high MnN-added stainless steel having the following composition. As a result, when used as a catheter, it has high strength and non-magnetic characteristics, improved characteristics such as torque transmission, flexibility, pressure resistance, buckling resistance, and inspection by interference and disturbance of environmental magnetic fields. It is possible to prevent distortion of the image of the device and to improve problems such as peeling of the resin material (composition uses mass%).

That is, the stainless steel is C ≦ 0.06% by mass%,
Si ≦ 0.80%,
Mn: 3.00 to 18.00%,
Ni: 2.00 to 13.00%,
Cr: 15.00 to 25.00%,
N: including a main part composed of 0.10 to 0.80%,
And the balance: Fe, and inevitable impurities,
Or Mo: 0.40 to 3.50% in the main part,
Cu: 0.08 to 0.80% of at least one kind is included,
And remainder: it is composed of Fe and inevitable impurities.

  As described above, the main part contains Mn 3.00 to 18.00% and N: 0.10 to 0.80%, thereby stabilizing the austenite phase and increasing the strength and demagnetization. Further, for example, corrosion resistance and toughness can be improved by the third element of Mo and Cu added as necessary.

Here, the reason for limiting the component amount of each element of the stainless steel will be described.
The addition of [C] is effective for making the crystal finer and adding mechanical properties, in particular, high strength. However, if it exceeds 0.06%, it causes a harmful carbide in the heat treatment performed in the production process, and there is a problem in workability when reducing the diameter, fatigue life due to repeated bending, preferably It is 0.03% or less, more preferably 0.010 to 0.03%.

  [Si] is a deoxidizing component required at the time of melting, and its addition improves fatigue, strength, and life characteristics. However, if it exceeds 0.80%, it causes σ phase formation, and more preferably is 0. 50 or less, more preferably 0.05 to 0.50%.

  [Mn] is effective because it improves the hot workability together with nickel and stabilizes the austenite phase, and the increase makes it possible to add a large amount of N, so that it is 3.00% or more, while 18.00 The effect is saturated even if it increases to exceed%. Preferably it is set to 3.50 to 17.50%. In particular, depending on the amount of Ni and N described later, for example, when Ni is 8.0 to 12.0%, the amount is 5.00 to 8.00%, and a smaller amount of Ni, for example 2.00 to 5.00. In the case of% Ni, it is preferable to increase it to 12.0-17.00%.

  [Ni] is an element necessary for making the substrate into a stable austenite structure, and is an element effective for improving the workability by promoting the oxidation resistance of chromium, and N effective for non-magnetism. From the relationship of addition, it is set to 2.00 to 13.00%. In particular, if it is less than 2.00%, it is difficult to expect the effect, and if it exceeds 13.00%, it is difficult to add a large amount of N, and the cost increases. Preferably, the content is 2.50 to 12.50%, and further from 8.00 to 12.00% or 2.00 to 5.00% as shown in the following example from the relationship with the amount of Mn and N.

  [Cr] improves the corrosion resistance and mechanical properties by dissolving in the dough of this alloy material, and has the effect at, for example, 15.00% or more, but forging above 25.00% Fatigue is reduced due to the effect on the performance. Preferably, it is 14.50 to 24.00%, and it is 19.00 to 23.00% or 16.00 to 20.00% as shown in the following example depending on the amount of Mn, Ni and N.

  [N] is a strong austenite-forming element and has the effect of increasing the toughness and yield point by refining crystal grains. The effect is effective when the stainless steel of the present invention is at least 0.10% or more. However, if it exceeds 0.80%, nitrides are easily formed and the workability is lowered. More preferably, it is 0.30 to 0.60%.

Further, the third element added as necessary includes the following.
(1) [Mo] is effective in improving strength and corrosion resistance by adding at least 0.40%, but if it exceeds 3.50%, the workability is lowered and the effect is saturated, which causes cost increase. Therefore, the content is preferably 0.45 to 3.45%. Furthermore, as shown in the following example, it is good to make it 1.00 to 3.00% or 0.40 to 2.00% depending on Mn and Ni.
(2) [Cu] reinforces the stainless steel dough, but the toughness is impaired and hot workability is reduced, so 0.08 to 0.80%. Similarly, from the relationship with other component elements, it is also preferable to set it to 0.40 to 0.7% as shown in the following example. Moreover, this Mo and Cu can add at least 1 type as needed.

  Furthermore, for example, the following two types of stainless steel having a more preferable form having such a composition can be presented, which is preferable in terms of characteristics.

  One of them is mass%, C: ≦ 0.03%, Si ≦ 0.50%, Mn5.00-8.00%, Ni: 8.00-12,00%, Cr: 19.00 Including 23.00%, Mo: 1.00 to 3.00%, Cu: 0.08 to 0.80 and N: 0.30 to 0.60%, the balance being composed of Fe and inevitable impurities is there.

  The other is mass%, C: ≦ 0.06%, Si ≦ 0.50%, Mln: 12.00-17.00%, Ni: 2.00-5.00%, Cr: 16 .00 to 20.00%, Mo: 0.40 to 2.00%, N: 0.30 to 0.60% and Cu: 0.40 to 0.70%, composed of the balance Fe and inevitable impurities It has been done.

  Further, the thin strip 4 has a predetermined tensile strength of 1500 to 3000 MPa together with the thickness t. If the pressure is less than 1500 MPa, operability and buckling resistance cannot be obtained. On the other hand, if the strength exceeds 3000 MPa, the toughness is inferior and it is difficult to improve the fatigue life. More preferably, it is 2000-2800 MPa, More preferably, it is 2100-2600 MPa.

  The magnetic permeability is also referred to as the magnetic permeability, and the relationship between the magnetic field strength H and the magnetic flux density B is indicated by a proportional constant μ when B = μH. ) And other various permeability measuring devices. In this case, since the thin strip 4 is a fine one having a thickness of 50 μm or less and there is a possibility that the variation of the measurement value may increase, for example, a large number of about 10 to 1000 pieces is bundled. Using a bundle, it is possible to use the value finally divided by the effective area of the measurement sample. This value is assumed to be non-magnetic with a value of 1.010 oersted or less. In the stainless steel having the above composition, the increase in magnetism accompanying cold working is extremely low, and the non-magnetic characteristics can be obtained.

  Among these stainless steels, for example, at least one of Nb, Ti, A1, and O is Nb: 0.020% or less, Ti: 0.030% or less, Al: 0.010% or less, O: 0.008% With those regulated below, various forms of precipitates such as inclusions and oxides can be suppressed in the stainless steel dough, and good characteristics can be obtained. More preferably, the total is 0.050% or less. Set to Further, as other impurities, for example, P ≦ 0.045% and S ≦ 0.030% are also preferable.

  That is, among these impurities, Nb, Ti, Al, and O in particular are factors that cause the occurrence of inclusions and oxides in the stainless steel dough, and in the case of a fine metal strip-like wire having a thickness of 50 μm or less as in the present invention. Since such a structural abnormality directly has a significant effect on its strength and fatigue, the amount of these impurities is controlled in accordance with its characteristics.

Further, in order to further improve the characteristics of the strip-like thin wire 4, it is preferable to adjust the relationship between the elements of the stainless steel so as to satisfy the following conditions.
Ni + 1.05Mn + 12.6N = (18.0-25.0%) ≧ 0.65Cr + 12.6C

  This relationship is based on the experiments of the present inventors, and uses a fine metal strip-like thin wire 4 as in the cylindrical mesh body 1, and has both high strength and non-magnetic characteristics. In particular, it is preferable to combine non-magnetization by stabilizing the austenite phase and high strength by work hardening. That is, the total value of the former elements Ni, Mn, and N that affects the stabilization of the austenite phase is set to 18.0 to 25.0%, and is larger than the total value of the latter Cr and C that affects the high strength characteristics. More preferably, the former total is set to be 1.3 to 2.2 times the latter total. From this relationship, it has been found that both the tensile strength and non-magnetic characteristics can be obtained.

Further, if necessary, the calculation value shown in the following formula A is adjusted to be in the range of 26 to 40%. Thereby, it is also preferable to promote the stabilization of the austenite phase to improve the chemical characteristics such as corrosion resistance and to interpret the problem of, for example, hydrogen embrittlement that occurs in the subsequent processing.
A = Ni + 0.65Cr + 0.98M0 + 1.05Mn + 0.35Si + 12.6C

  Further, the stainless steel strip-like thin wire 4 used in the present invention is processed by cold rolling so as to have a predetermined thickness after, for example, solution heat treatment, and is particularly 20 μm or less and about 4 to 8 times the thickness. In the case of the one that has been hard-worked at once in a wide width, a micro unevenness d (shown in FIG. 2) is generated on the side surface of the width along with the rolling process, thereby increasing the variation in width dimension, for example, cutting at a local recess. It causes breakage due to chipping phenomenon.

  In order to suppress this phenomenon, for example, after a solution heat treatment at 900 to 1100 ° C., cold wire drawing at a working rate of about 40 to 95% is once performed, and the crystal structure in the stainless steel is extended in the longitudinal direction. This can be solved by adopting a so-called two-stage processing method in which a fiber structure is formed and further cold-rolled without being softly processed. The rolling reduction of the cold rolling process is performed at a predetermined thickness of, for example, 50% or more.

  In other words, by adopting such a two-step processing method, the spread in the width direction during rolling is smooth and uniform to prevent unevenness on the side surface of the width and to suppress dimensional variations, and further, work hardening by wire drawing. By using this, it is possible to obtain a high strength that cannot be obtained simply by rolling.

  This means that although both processes are pressing, higher work hardening is obtained in wire drawing than when pure drawing is performed, whereas in rolling, there are parts that run away in the unconstrained width direction. In general, the strength increase rate is very small due to the difference in the amount of processing, but in the present embodiment, this can be improved. At the same time, the yield strength ratio {(τ / σ) × 100} between the tensile strength (σ) and the 0.2% yield strength also becomes the thin strip 4 4 rich in elasticity of 85 to 98%. As a result, it is excellent in repeated fatigue and buckling resistance.

  In that case, the side surface portion of the strip-like thin wire 4 has a surface roughness that is coarser than the flat surface 3 by rolling in the vertical direction, for example, by projecting in the side direction as seen in FIG. Have For example, the average surface roughness (Rz) of 10 points measured along the longitudinal direction is obtained, and for example, the roughness is about Rz = 0.04 to 0.1 μm. The surface irregularities of this level are fine so as not to affect the quality performance of the band itself, and when the resin material is encapsulated on the surface as a catheter, the coupling between the two is strengthened to enhance the integration. be able to.

It said tubular net body 1, in the catheter 2 described above is shown in FIG. 6, the flexible without fine long as the tube body A with, thus reinforcing the catheter 2. For example, as shown in FIG. 3, the tube body A is a long cylindrical molded product having an outer diameter of 0.5 to 3 mm and a film thickness of about 0.2 to 0.8 mm, and transmits torsion torque. In order to enhance torque transmission, flexibility, pressure resistance, and buckling resistance, the cylindrical net 1 is provided, and a resin layer 7 including an inner resin layer 7A on the inner surface and an outer resin layer 7B on the outer surface. Encapsulated and integrated.

  The type and coating method of the resin material used for the inner resin layer 7A and the outer resin layer 7B are not particularly limited as long as they have safety / compatibility for a living body, and are conventionally used, for example. Various resin materials such as polypropylene, polyethylene, polyamide, polyvinyl chloride, polyester, polyacetal, polyurethane, polycarbonate, fluororesin, silicone resin, silicone rubber, and natural rubber can be used. In addition, it can also integrally form through the mesh | network of the cylindrical net body 1 using a thermoplastic resin material, Furthermore, either one of the said inner resin layer 7A and the outer resin layer 7B is abbreviate | omitted, or said inner resin layer 7A One of the outer resin layer 7B and the outer resin layer 7B can be formed of a plurality of layers. The inner resin layer 7A and the outer resin layer 7B may be made of different resins, and may be modified in various ways, for example, the inner and outer resin layers 7A and 7B may be formed via an intermediate layer straddling the cylindrical net body 1.

  Samples A1 to A5, which are stainless steel wires having the compositions according to the present invention shown in Table 1, and SUS304, SUS304N material, and SUS316, which are general hard wires, are used as comparative samples B1 to B3. Selected as. The component composition is shown together in Table 1.

The stainless steel wires of Samples A1 to A5 shown in Table 1 were each wet-drawn with a diamond die (processing rate 75%) to obtain 0.05 mm hard strands (Examples A1 to A5). Each of the obtained hard strands had a smooth and brilliant surface state, and could be drawn smoothly. Therefore, this strand is set in an ultrathin rolling mill, and cold rolling is performed in which the tensile strength of the fine wire is reduced from two directions while applying a reverse tension of 5 to 20%, and the thickness is 20 μm × width. A thin strip 4 having a thickness of 100 μm was obtained. No heat treatment was performed during that time. The obtained band-like thin wire 4 had a good surface, and there was almost no variation in the width dimension and there was no linear defect, and no defect that was regarded as a problem was observed. However, when the side surface portion was observed with a microscope, fine irregularities coarsened from the pressing surface were confirmed, the degree of which was about 0.04 to 0.09 μm with an average surface roughness of 10 points, There is no substantial impact. Table 2 shows the mechanical properties after the cold rolling and the results of repeated bending tests. Similarly, hard wires (comparative examples B1 to B3) are obtained for the samples B1 to B3 of the comparative example, and the results are shown in Table 2.

  The mechanical properties are also obtained from the chart results of strain and stress by performing a thin wire tensile tester with a chart based on JIS-Z2201 “Metal Material Tensile Test” at a distance between gauge points of 50 mm. The Young's modulus indicates the slope within the proportional limit region in the chart. The magnetic permeability is a bundle of 50 band-like thin wires. The magnetic permeability (μ) at an environmental temperature of 20 ° C. is measured by the DC magnetization characteristic test apparatus (Metron Giken Co., Ltd.), and this is measured in unit area. It is converted. As is clear from these results, it can be seen that the thin strips of this example all have high strength equal to or higher than that of the comparative strips, and both are nonmagnetic less than 1.01 Oersted.

As for the repeated bending test, as shown in FIG. 4, each obtained strip-like thin wire is gripped by gripping tools d and d at a distance between the gauge points of 80 mm, and one of them is broken while being repeatedly bent at an angular range of 180 °. The number of times of bending up to is measured, and the result is shown by counting the bending angle of 90 ° as one time, but it can be seen that it is substantially better than the comparative example. Corrosion resistance is evaluated by evaluating the pitting corrosion potential (VVSAg / Agcl) according to the anodic polarization curve under the condition of 100 μA / cm ^2. Excellent is indicated by ◎, good is indicated by ○, and inferior is indicated by Δ, ×. ing. Samples A1 and A2 were particularly good.

Next, in order to see the effect of the low-temperature heat treatment, each hard fine wire of Example A1 (Sample A1) and Comparative Example B1 (Sample B1) was subjected to a temperature of 400 to 600 ° C. × 15 to Processing was performed for 60 min, and the characteristics of the obtained strip-like thin wires were investigated. As shown in FIG. 5, the strength of the stainless steel strip-like wire according to the present invention increases with the treatment temperature. For example, when the treatment is performed at a temperature of 450 ° C., the tensile strength is increased to about 100 to 200 MPa . In addition, the yield strength ratio was very excellent at 96%.

  Next, a process different from that of Example 1 was adopted, and a stainless steel wire having the composition of Samples B1 to B3 was subjected to a solution heat treatment at a temperature of 1150 ° C. to obtain a 0.1 mm raw material wire (Comparative Examples B1 to B3). ). Then, this was set in the cold rolling mill and rolled at a rolling reduction of 70% to obtain a strip-like thin wire having a fine cross section of 30 μm thickness × 260 μm width.

  The properties of the thin strips were tensile strength of 1500 to 1800 MPa, Young's modulus of 170 to 200 GPa, and good rolling workability. Baracki was a little big.

  Next, using the metal strip-like thin wires of Examples A1 and A3 of Example 1, a plain weave braided with an outer diameter of 1.4 mm, a pitch of 4 mm, and a wiring interval of 0.42 mm is obtained. It was. In the braiding process, a film body in which a polytetrafluoroethylene resin having a thickness of 0.3 mm is formed on the surface of a rod-shaped core material prepared in advance is formed by an alternating knitting brader using the above-described eight strip thin wires. It was braided at a density of 80 picks / inch, and the surface was coated again with the resin material to form a tube-like capillary tube. Finally, the core material was drawn. The net was very flexible and highly elastic, and had excellent nonmagnetic properties.

  In order to evaluate the performance of the coated catheter thus obtained, a sample having a length of 100 mm was collected and investigated for torque transmission, pressure resistance, and buckling performance. Torque transmission is determined by sensation of the twisting force on the other end when one end of the test sample is twisted, and pressure resistance is evaluated by the presence or absence of rupture when a drug solution is injected into the catheter with a syringe. Further, the buckling resistance was evaluated by placing one end of the sample on a desk and pressing it from the top, and evaluating the amount of stress when buckling. As a result, the catheter according to the present invention was excellent in any performance, and the characteristics could be improved by about 20 to 30% as compared with the conventional catheter.

It is a front view which illustrates one form of the cylindrical net body which braided the strip | belt-shaped thin wire | line of this invention. It is a perspective view which illustrates the ultrathin strip-like thin wire concerning the present invention. (A) is a cross-sectional view illustrating an embodiment of a tube body of a catheter, and (B) is a front view showing an outer resin layer and a cylindrical mesh body sequentially removed. 1 is a schematic diagram showing a method of a repeated bending test. It is a diagram which shows the change of the mechanical characteristic accompanying low temperature heat processing. It is a perspective view which shows one form of a catheter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylindrical mesh body 2 Catheter 3 Uneven plane 4 Band-shaped thin wire 7 Resin layer 7A Inner resin layer 7B Outer resin layer

Claims (8)

A cylindrical net formed by forming a thin tube-shaped braid by braiding a strip-shaped thin wire pressed to a thickness of 50 μm or less and having a flat surface,
The strip-shaped thin wire is stainless steel,
The composition is mass%, C ≦ 0.06%,
Si ≦ 0.80%,
Mn: 3.00 to 18.00%,
Ni: 2.00 to 13.00%,
Cr: 15.00 to 25.00%,
N: The main part which consists of 0.100-0.800%,
And the balance: Fe, and inevitable impurities,
Or Mo: 0.40 to 3.50% in the main part,
Cu: 0.08 to 0.80% of at least one kind is included,
And the balance: composed of Fe and inevitable impurities,
The band-like thin line tensile strength (sigma) is 1500～3000MPa, tubular catheter reinforcing characterized and Turkey that permeability at ambient temperature 20 ° C. have a high strength non-magnetic characteristics of 1.01 or less Net body.
The stainless steel has a mass% and the main part is
C: ≦ 0.03%,
Si ≦ 0, 50%,
Mn: 5.00 to 8.00%,
Ni: 8.00 to 12.00%,
Cr: 19.00-23.00%,
N: 0.30 to 0.60%, and in this main part Mo: 1.00 to 3.00%,
Cu: 0.08 to 0.80% of at least one kind is included,
In addition, the cylindrical net body according to claim 1, further comprising: balance: Fe and inevitable impurities. The stainless steel has a mass% and the main part is
C ≦ 0.06%,
Si ≦ 0.50%,
Mn: 12.00-17.00%,
Ni: 2.00 to 5.00%,
Cr: 16.00 to 20.00%,
N: 0.30-0.60%, and in this main part Mo: 0.40-2.00%,
Cu: at least one of 0.40 to 0.70% is included,
In addition, the cylindrical net body according to claim 1, wherein the cylindrical net body is constituted by the balance: Fe and inevitable impurities. The inevitable impurities are at least one element of Nb, Ti, A1, O, and the content of the element is mass%,
Nb: 0.020% or less,
Ti: 0.030% or less,
Al: 0.010% or less,
O: It is 0.008% or less, The cylindrical net body in any one of Claims 1-3 characterized by the above-mentioned. The cylindrical mesh body according to claim 4, wherein the stainless steel satisfies the following relational expression in mass% of the element.
Ni + 1.05Mn + 12.6N = (18.0-25.0%)
≧ 0.65Cr + 12.6C   The strip-like thin wire has a thickness of 20 μm or less and a width of 2 to 10 times the thickness by cold drawing after the solution heat treatment and cold rolling after the drawing. The said cylindrical net body in any one of Claims 1-5 characterized by the above-mentioned. The proof stress ratio {(τ / σ) × 100} between the tensile strength (σ) MPa and 0.2% proof stress (τ) MPa is 85 to 98%. The cylindrical net.
  A catheter having a tube body formed by arranging and encapsulating a resin material on the inner and outer surfaces of the cylindrical mesh body according to any one of claims 1 to 7.

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