JP5497604B2 - Manufacturing method of medical guide wire - Google Patents

Description

In the present invention, the mechanical strength of the metal wire of the core wire is obtained by subjecting the metal wire of the core wire made of stainless steel wire to a high-strength wire drawing process or applying a low-temperature heat treatment in a certain temperature range after the wire drawing process. The present invention relates to a medical guide wire with improved characteristics, linearity, and the like, and a method for manufacturing the same.

Since the medical guide wire inserted into the blood vessel is a thin wire or an extra fine wire, it is necessary to satisfy safety ensuring for the human body in consideration of mechanical strength characteristics, and various proposals have been made.

Patent Document 1 describes a predetermined degree of processing and low-temperature heat treatment conditions using high silicon stainless steel (Si: 3.0% to 5%), and aims to improve torque transmission of the core material.
However, while this document uses high silicon stainless steel, the present invention improves the tensile strength of the core wire by using a conventional austenitic stainless steel wire (such as SUS304) without using high silicon stainless steel. The technical idea is different from the present invention for the purpose of obtaining a medical guide wire having improved linearity and the like.

Patent Document 2 discloses a medical guide wire made of a core material having a high strength of 2800 MPa or more, and aims to improve the torque transmission performance of the core material as in Patent Document 1.
However, this core material is made of high silicon stainless steel as described above, and is different from steel materials using the present invention (stainless steel SUS304, SUS316, etc.), and improves the tensile breaking strength of the metal wire of the core wire of the present invention. This is different from the technical idea of improving linearity and the like.

Patent Document 3 aims to improve the rotational operability by applying electrical resistance heating at the same time as the twisting while providing a difference between the primary twisting and the secondary twisting while applying a tensile load to the metal wire. . However, this manufacturing method means over-twisting up to the vicinity where slip lines (Ludders lines) are generated on the surface of the fine metal wire, whereas the present invention does not mean over-twisting. Absent. In addition, the linearity in the correlation between the tensile load and the number of twists has not been elucidated, and the correlation between the total area reduction of the wire drawing of the fine metal wire and the tensile fracture strength by the low temperature heat treatment It is not described at all.

JP 2003-342696 A JP 2004-194768 A Japanese Patent No. 4141336

In a conventional medical guide wire, a stainless steel wire is used as the metal wire of the core wire, and a metal wire that is strongly processed by repeated strong wire drawing and low-temperature heat treatment, and the heat of the strongly processed metal wire Focusing on the effect of improving the mechanical strength characteristics due to the influence, by applying low-temperature heat treatment suitable for the steel type after drawing in a temperature range where the tensile breaking strength of the hard-worked metal wire steeply increases, There is no technical idea to improve the tensile breaking strength of the wire.
And furthermore, twisting under predetermined conditions under low-temperature heat treatment suitable for the steel type in a temperature range in which the tensile breaking strength of the metal strand is steeply increased using a metal strand having a high strength tensile breaking strength, In addition, there is no technical guide wire for improving the linearity and the like by a low-temperature heat treatment after twisting under a predetermined condition and the technical idea of the manufacturing method.

An object of the present invention is to use a metal wire as a core wire, and the metal wire is obtained by a strong wire drawing of an austenitic stainless steel wire, or by accumulating wire drawing and low-temperature heat treatment. By applying a low-temperature heat treatment in a temperature range suitable for the steel type using the thermal characteristics of the metal strand of the wire after drawing, the tensile breaking strength of the metal strand is improved, and the tensile strength of the metal strand is further increased. Technology to improve linearity, etc. by twisting under specified conditions under low-temperature heat treatment suitable for steel types in a temperature range where the breaking strength steeply increases, or by low-temperature heat treatment after twisting under specified conditions Disclosed is to provide a medical guide wire that has high resistance to repeated bending fatigue and can be operated safely by an operator.

According to the first aspect of the present invention, a core wire made of a flexible slender body, a coil spring body in which the core wire is inserted into a tip portion of the core wire, are mounted, and the core wire and the coil spring body are used as a joining member. In the manufacturing method of the partially joined medical guide wire, the core wire is composed of a metal wire, and the metal wire is a wire drawing process using a remelted material of austenitic stainless steel wire that has been subjected to a solution treatment. and a low-temperature heat treatment step after the drawing step was repeated at least one or more sets as a set, provided the final drawing step and the final drawing step after the low temperature heat treatment step,
The total area reduction ratio until the final wire drawing step is 90% to 99.5%, and the low temperature heat treatment step after the wire drawing step and the low temperature heat treatment step after the final wire drawing step are performed at 300 ° C. to 495 ° C. 10 minutes to 180 minutes, or when the metal strand is an austenitic stainless steel wire containing Mo, the temperature is from 300 ° C. to 525 ° C. for 10 minutes to 180 minutes, and the low temperature after the wire drawing step until the final wire drawing step The total increase rate of the tensile breaking strength of the metal wire by the heat treatment step is 8% or more, and after the low-temperature heat treatment step after the final wire drawing step , the metal wire is attached to one end of the metal wire. In a state where a load load of 5% to 30% of the tensile breaking force of the metal wire before twisting is applied, the other end is set to a twisting process of 100 times / m to 275 times / m, The temperature of the metal wire is from 300 ° C The twisting step, which is a low-temperature heat treatment step at 495 ° C. for 30 seconds to 180 minutes, or when the metal strand is an austenitic stainless steel wire containing Mo at 300 ° C. to 525 ° C. for 30 seconds to 180 minutes. In the subsequent low-temperature heat treatment step, when the tensile breaking strength of the metal wire is Y (kgf / mm @ 2) and the total area reduction is X (%), 450.gtoreq.Y.gtoreq.2. 15 satisfy the relation of 0X + 70, a medical guide wire manufacturing method which is characterized in that it consists the core wire using the metal wire.
With this configuration, the rate of increase in the breaking strength of the core wire can be further increased, and a thinned core wire can be stably manufactured, and under low temperature heat treatment suitable for steel types in a temperature range where the tensile breaking strength increases steeply. By performing a low-temperature heat treatment step after twisting on a core wire that has been subjected to low-temperature heat treatment after the final wire drawing step , twisting in a cold state is performed rather than twisting in a hot state By further promoting the refinement of crystal grains, and by adopting a low-temperature heat treatment process suitable for the steel type in the temperature range where the tensile fracture strength increases steeply thereafter, higher linearity / rotational transferability and higher tensile strength are achieved. A medical guide wire made of a core wire having a breaking strength can be manufactured.

According to a second aspect of the invention, the medical guide wire The method according to claim 1, before Symbol twisting processing step, tension of the metal wire before twisting process to one end of the metal wire break It is characterized by comprising the core wire using the metal element wire, with the other end being a twisting process of 100 times / m to 200 times / m with a load applied of 5% to 30% of the force. This is a method for manufacturing a medical guide wire.
With this configuration, the low-temperature heat treatment process is a low-temperature heat treatment condition suitable for the steel type in a temperature range where the tensile breaking strength of the core wire increases more steeply, and the twisting process has a hardness distribution of the surface layer portion and the inner layer portion of the core wire. By adopting the twisting process conditions that homogenize with extremely little inhomogeneity, the core wire has extremely high linearity and rotational transmission, no bending at the tip, and further improved resistance to repeated bending fatigue. A medical guide wire made of a core wire can be manufactured.

According to a third aspect of the invention, the medical guide wire The method according to claim 1 or 2, before Symbol twisting processing step, the other while applying a load weight on one end of the metal filaments Twisting the load weight W (kgw) to the tensile breaking force P (kgf) before twisting of the metal wire is defined as a load weight ratio X (%), and the load weight ratio X (%) is W ÷ In the case of the relationship of P × 100, the number N of twists (times / m) satisfies the relational expression of −0.8X + 124 ≦ N ≦ −1.8X + 284 and is composed of the core wire using the metal strand. It is the manufacturing method of the medical guide wire characterized.
With this configuration, the low-temperature heat processing step after twisting processing step, clarified and a high degree of linearity, the rotation transmission properties and high tensile strength at break the correlation between the number of twist and the load weight of the twisting processing step A medical guide wire using a core wire having both characteristics can be manufactured.

According to a fourth aspect of the present invention, in the medical guidewire according to the third aspect , in the twisting process, the other end is twisted with a load applied to one end of the metal strand, The ratio of the load weight W (kgw) to the tensile breaking force P (kgf) before the wire twisting process is defined as a load weight ratio X (%), and the load weight ratio X (%) is expressed as W ÷ P × 100. In this case, the medical guide is characterized in that the number N of twists (times / m) satisfies the relational expression of −0.8X + 124 ≦ N ≦ −2.8X + 264 and is composed of the core wire using the metal strand. It is a manufacturing method of a wire.
With this configuration, the low-temperature heat processing step after twisting processing step, and a correlation between the number of twist and the load weight of the twist processing steps clearer, and higher degree of linearity-rotation transmission, more sophisticated It is possible to manufacture a medical guide wire using a core wire having both of the tensile rupture strength characteristics.

It is the coil spring body assembly | attachment figure of a medical guide wire, and the front view and principal part enlarged view of a core wire. It is a total area reduction rate and tensile breaking strength characteristic view. It is a temperature and tensile breaking strength characteristic view. It is a relational characteristic figure of the total area reduction of a metal strand, and tensile breaking strength. It is Example 2 for a medical guide wire. It is Example 3 for a medical guide wire. It is Example 4 for medical guide wires. It is a characteristic view of the number of twists and tensile breaking strength. It is a characteristic view of the number of twists and a bending residual angle. This is a twisting manufacturing method by electric resistance heating. It is a characteristic figure of the frequency | count of twist and load weight ratio. It is a state figure of a leg vascular lesion part treatment. 1 is an assembly of a medical guide wire and a microcatheter.

The best embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a medical guide wire (hereinafter referred to as a guide wire) 1A according to a first embodiment of the present invention, and a coil spring body (hereinafter referred to as a coil body) that is coaxially fitted around the core wire tip 21 of the core wire 2. 3, a radiopaque coil 31 made of gold, platinum, tungsten or the like on the front end side of the coil body 3 and a metal having a wire diameter d0 of stainless steel wire on the rear end side of 0.050 mm to 0.095 mm. The core wire 2 includes a radiation transmitting material coil 32 formed by winding a strand, and the core wire tip 21 of the core wire 2 includes an intermediate front joint 41, an intermediate rear joint 42, and a rear joint 43, which are intermediate joints. Accordingly, the core wire 2 and the radiopaque material coil 31 or the radiopaque material coil 32 are partially joined by using the joining member 4, and a rounded cylindrical lead plug at the tip end portion of the core wire 2. 5 is joined by the joining member 4 Manner is joined to, and bonding the core wire 2 and the radiopaque material coil 31 the line diameter is wound forming a metal wire 0.095mm from 0.050 mm.
The intermediate front side joining portion 41 has one end of the radiopaque material coil 31 and one end of the radiation transmissible material coil 32 abutting or screwed together so that dissimilar metals are integrally joined and joined to the core wire tip 21. The members 4 are partially joined.

The radiation transmitting material coil 32 has a coil wire having a wire diameter d 1 of 0.050 mm to 0.095 mm, and outer diameters D 1 and D 2 of the coil body 3 of approximately 0.228 mm to 0.457 mm. The length is made of an austenitic stainless steel wire of 30 mm to 300 mm. Further, about 300 mm in the longitudinal direction from the distal end of the core wire tip 21 of the core wire 2 is a thin wire having a diameter of about 0.060 mm to 0.200 mm, and the remaining core wire proximal portion 22 is about 1200 mm to about 2700 mm in the longitudinal direction. Thus, the outer diameter D7 consists of a thick line consisting of 0.228 mm to 0.457 mm. The small-diameter portion of the core wire tip 21 gradually changes and contracts toward the tip, and the cross-sectional shape thereof may be either a circular cross-section or a rectangular cross-section (shown (D)). In addition, a resin film 6 such as a fluorine resin or a urethane resin is formed on the outer periphery of the core wire 2 and the coil body 3, and a hydrophilic film 7 such as polyvinyl pyrrolidone that exhibits lubricating characteristics when wet is formed on the outer periphery. The coil body 3 is hermetically encapsulated by a two-layer structure of the resin coating 6 and the hydrophilic coating 7 that directly contact the outer periphery. In addition, illustration (C) shows an AA cross-sectional view of the intermediate rear joint 42.

The core wire 2 is composed of a metal strand, and the metal strand is drawn using a solution-treated austenitic stainless steel wire with a total area reduction of 90% to 99.5%. The breaking strength is 250 kgf / mm 2 or more and 450 kgf / mm 2 or less. Here, the total area reduction ratio means a wire before drawing of a wire using a solid solution-treated wire (for example, a wire having a property of tensile fracture strength of 60 kgf / mm 2 to 80 kgf / mm 2 by heat treatment at 1050 ° C.). The cross-sectional area difference between the diameter and the finished wire diameter of the final wire drawn through a wire drawing process using a plurality of dies is referred to as a reduction rate. Even if the wire is drawn using a die, the area is reduced after the first wire drawing step, and the entire wire drawing step (in the table, the primary wire drawing, or the wire drawing step from the primary wire to the secondary wire) is performed. The reduction in area is classified as the total reduction in area for explanation. In addition, the tensile breaking strength is a value obtained by dividing the value obtained when a tensile force is applied to a wire by the sectional area of the wire, and the tensile breaking force is a value obtained when a tensile force is applied to the wire. Means the value of In addition, the “low temperature heat treatment” referred to here is annealing that lowers the tensile strength at break and softens the steel wire by reducing the hardness, or low temperature annealing, and heats above the transformation point (eg, Ac3 about 730 ° C. or higher). Unlike normalizing, it is called “low temperature heat treatment” and distinguished from heat treatment in which the tensile strength at break increases and mechanical properties are improved.

And, the above-mentioned metal element wire was made into “solution-drawn austenitic stainless steel wire drawing” in order to obtain an austenitic structure with good workability, and the austenitic stainless steel wire was heat-treated using a transformation point. This is because the crystal grains cannot be refined by the above-described method, the crystal grains can be refined only by cold working, and the tensile strength can be improved by exhibiting remarkable work-hardness by the wire drawing. Also, the reason for using austenitic stainless steel wire is that martensitic stainless steel wire shows quench hardenability by heat treatment and is easily affected by heat, and precipitation hardened stainless steel wire (SUS630 etc.) has insufficient toughness and is a coil. This is because breakage is likely to occur during forming, and the ferritic stainless steel wire has a problem of temperature brittleness (sigma brittleness).

And in the intermediate front side joining part 41 which joins the core wire 2 and the coil body 3 using the joining member 4 as soldering or brazing, the radiopaque material coil 31 having a wire diameter of 0.050 mm to 0.095 mm, An end of the metal wire with a radiation transmitting material coil 32 having a wire diameter d0 of 0.050 mm to 0.095 mm comes into contact with or is screwed, and the wire diameter ranges from 0.060 mm to 0.005 mm. In the joining with the core wire 2 of 150 mm, and in the intermediate rear side joining portion 42, the radiation transmitting material coil 32 having the same metal wire diameter as described above and the wire diameter of the metal strand is about 0.100 mm to 0.200 mm. In the joining with the core wire 2, the joining shape of the intermediate front side joining portion 41 and the core wire 2 of the intermediate rear side joining portion 42 is such that the widths L1 and L2 are about 0.3 mm to 1.5 mm and the outer diameters D3 and D4. Is 0.232 Each of mm to 0.480 mm has a substantially cylindrical shape like a donut, and the rear end joint 43 includes a radiation transmitting coil material 32 having a wire diameter d0 of the same metal wire as described above and a wire diameter 0 of the metal strand. In the joining with the core wire 2 of about 200 mm to 0.345 mm, the joining shape is a cylindrical shape having a width L3 of about 0.3 mm to about 3 mm and an outer diameter D5 of about 0.232 mm to about 0.480 mm, or at hand It has a substantially conical shape with a tapered side.

Further, the leading plug 5 is composed of a radiopaque material coil 31 having the same metal wire diameter as described above using the joining member 4 and a circular cross-sectional shape having a wire diameter of about 0.060 mm to 0.100 mm. Alternatively, it is joined to the core wire 2 having a rectangular cross-sectional shape 23 (shown (D)), and the joined shape is a tip having a width L4 of about 0.2 mm to 1.5 mm and an outer diameter D of about 0.232 mm to 0.480 mm. A substantially cylindrical lead plug 5 having a rounded tip side is shown, and this shape may be any of a cylindrical shape, a hemispherical shape, and a conical shape toward the distal end side, even if it is not a rounded shape. The partial joining using the joining member 4 here means that the intermediate joining portion (reference numerals 41 and 42), the rear end joining portion 43, and the leading plug that are joined using the joining member 4 in the first embodiment. 5 is a joining form of the coil body 3 and the core wire 2.
Therefore, there is no intermediate joint (reference numerals 41 and 42), and only the leading plug 5 and the rear end joint 43 may be provided. In addition, the coil body 3 welds and joins each end part of the dissimilar metal of the metal wire of the radiopaque material and the metal wire of the radiopaque material, which will be described later, and then wire-drawn the wire into a coil shape. A coil body structure formed by winding may be used.

Next, Tables 1-2 show the metal strands used for the core wire 2 of the present invention, and Table 3 shows a comparative example.

Tables 1 and 2 show the metal wires used for the core wire 2 of the present invention, using a wire diameter (1.080 mm) of a wire rod (bus wire) having a tensile breaking strength of 70 kgf / mm @ 2 for a solution treated austenitic stainless steel wire. The primary drawing was performed with a reduction in area of 87.6% and a wire diameter of 0.380 mm, followed by primary low-temperature heat treatment at 420 ° C. for 75 minutes, and then secondary reduction with an area reduction of 19.9%. Using wire processing, a metal strand 1a having a total area reduction of 90%, a wire diameter of 0.340 mm and a tensile breaking strength of 252 kgf / mm 2, and a wire diameter (bus wire) of 1.390 mm is also used. , Primary wire drawing, primary low-temperature heat treatment, secondary wire drawing, a metal wire 1c having a total area reduction rate of 94.0%, a wire diameter of 0.340 mm, and a tensile breaking strength of 267 kgf / mm 2, or the like The wire diameter of the wire (bus) is 1.3 Using 0 mm, primary wire drawing, primary low-temperature heat treatment, and secondary wire drawing were performed, the total area reduction rate was 97.0%, the wire diameter was 0.228 mm (0.009 inch), and the tensile strength at break was 296 kgf / This is a metal wire 1e of mm2.

The metal strands 1b, 1d, and 1f are subjected to secondary low-temperature heat treatment after the final drawing of the metal strands 1a, 1c, and 1e, respectively, to improve the tensile breaking strength to 257 kgf / mm 2 to 321 kgf / mm 2. It is. Further, 1 g of a metal wire represents an example of a metal wire using a remelted material. The wire diameter of a wire material (bus wire) having a tensile breaking strength of 70 kgf / mm 2 of a solidified austenitic stainless steel wire is 3. 230 mm is used, the total area reduction rate is 99.5%, the wire diameter of the metal strand is 0.228 mm, and the tensile breaking strength is 400 kgf / mm 2. The metal strand 1h is the metal strand 1g After the final wire drawing (after the third wire drawing), a third low-temperature heat treatment is applied to obtain a tensile breaking strength of 424 kgf / mm 2.
In Table 3, Comparative Example 1 is the primary wire drawing when the total area reduction is 80.8%, and Comparative Example 2 is added as a comparative low temperature heat treatment for Comparative Example 1. The metal strands 1a to 1d are made of SUS304 material, and the metal strands 1e to 1h are made of SUS316 material containing 2 to 3% by weight of Mo, of which the metal strands 1g and 1h are described later. The re-melting material SUS316 was used.

According to Tables 1 to 3, Examples 1b and 1d having a total area reduction of 90% and 94.0% are in the temperature range after the final wire drawing (after the secondary wire drawing) of the metal strands 1a and 1c. Is subjected to secondary low-temperature heat treatment (420 ° C., 75 minutes in this example) at 180 to 495 ° C., the increase rate of the tensile strength at break is 14.1. %, And 17.5%, which is an improvement of about 4.4 to 5.5 times that of Comparative Example 2 having a total area reduction rate of 80.8%.
The metal wire 1f having a total area reduction rate of 97.0% was subjected to the same primary low-temperature heat treatment as described above after the primary wire drawing of the metal wire 1e, and then the final wire drawing (secondary wire drawing). By adding the same secondary low-temperature heat treatment to the above, the total increase rate of the tensile strength at break is 21.7%, which is about 6.8 compared to Comparative Example 2 in which the total area reduction rate is 80.8%. Double the improvement.
Further, the tensile strength at break of metal wire 1h having a total area reduction of 99.5% was 424 kgf / mm @ 2, the highest value in the examples, and the tensile break at a total area reduction of 99.5%. The strength can be ensured to be 400 kgf / mm 2 or more, and the total increase rate of the tensile strength at break is 38.1%, which is about 11.9 times higher than that of Comparative Example 2.

In addition, according to Tables 1 and 2, according to Tables 1 and 2, the rate of increase in tensile fracture strength of the low-temperature heat treatment (primary low-temperature heat treatment) until the final wire drawing (secondary wire drawing) of the metal strands 1a to 1f is 12.1. % To 13.3%, which is 8% or more, and the rate of increase in tensile fracture strength of low-temperature heat treatment (primary and secondary low-temperature heat treatment) until the final wire drawing (tertiary wire drawing) of the metal wire 1g to 1h. The total of 32.1% is well over 8% and 10% or more.

FIG. 2 shows the total area reduction ratio (%) and tension of each Example (metal strands 1b, 1d, 1f, 1h) and Comparative Example 2 in which low-temperature heat treatment was applied after the final wire drawing in Tables 1 to 3 above. The figure shows the relationship with the breaking strength (kgf / mm2), where there is an inflection point where the tensile breaking strength increases further when the total area reduction is about 90%, and the total area reduction is about 94%. In the vicinity of 97%, the inflection point increases rapidly.
That is, the total increase rate of the tensile breaking strength by low-temperature heat treatment of the metal strand 1b having a total area reduction of 90% is 14.1%, and similarly, the metal strand 1d having a total area reduction of 94% is 17. 5%, a 3.4% increase over the metal wire 1b with a total surface reduction rate of 90%, and similarly, the metal wire 1f with a total surface reduction rate of 97% has a total decrease of 21.7%. It increases by 4.2% compared to the metal wire 1d having a surface area of 94%, and the metal wire 1h having a total surface area reduction of 99.5% is 16. 4% increase.
From the above, it is clear that the tensile breaking strength sharply increases when the total area reduction ratio of the metal strand used for the core wire 2 is 90% to 99.5%, and after drawing the metal strand By applying a low-temperature heat treatment under the predetermined conditions, the tensile strength at break of the metal strand is further increased. And the total of the increase rate of the tensile fracture strength of the low-temperature heat treatment until the final wire drawing in each Example of the metal strand of the present invention shows that it exceeds 10% and at least 8%, and as a result, tensile fracture The strength exceeds 250 kgf / mm @ 2, and a core wire 2 made of metal strands of 252 kgf / mm @ 2 to 424 kgf / mm @ 2 can be obtained.

Further, the total area reduction ratio in the wire drawing of the metal wire used for the core wire 2 is desirably 90% to 99.5%, more preferably 94% or more and 99.5%, and still more preferably 97% or more and 99. More preferably, the upper limit of the total area reduction is 99% or less.
And the total area reduction rate is set to 90% or more because the total area reduction rate exceeds 80% (see page 3 of Spring 3rd edition Maruzen Co., Ltd., page 2.82), and 90% or more is the boundary. This is because an inflection point where the tensile strength at break is further increased was found. (Figure 2)
Further, it is more preferably 94% or more, and further preferably 97% or more and 99.5% or less. When the total area reduction is 94% or 97%, as described above, the tensile fracture strength is higher. This is because an inflection point that dramatically increases was found, and the total area reduction rate was set to 99.5% or less. With a high degree of wire drawing that exceeds this, voids began to form in the metal structure. This is because the embrittlement is remarkable and the disconnection of the metal element wire is likely to occur.
Furthermore, the most preferable aspect is that the upper limit of the total area reduction rate is 99%, in particular, the core wire tip 21 of the core wire 2 is often formed into a rectangular cross-sectional shape by pressing (see FIG. 1 (D)). In such a case, since the metal strand having the high tensile breaking strength is insufficiently stretched during the pressing process, the surface of the outer peripheral portion of the core wire tip 21 is likely to crack, and has a predetermined dimension. This is because pressing becomes difficult.

In addition, the tip end portion 21 of the core wire is ground on the outer periphery of the tip end portion of the core wire 2 so as to be gradually changed and reduced in diameter toward the tip end, and pressed on the most distal end portion to obtain a rectangular cross-sectional shape (FIG. 1, Therefore, concentrated stress and residual strain are locally generated by grinding or pressing.
The pressing process of the core wire tip 21 may be performed after the final low-temperature heat treatment of the metal strand, but after the final drawing (secondary drawing, metal in the metal strands 1a to 1f). It is desirable to perform pressing on the strands 1g and 1h (third wire drawing) and then perform low-temperature heat treatment under predetermined conditions.
The reason for this is that the low-temperature heat treatment is performed after the final wire drawing and then the metal wire having a high strength tensile breaking strength is pressed, and the outside of the core wire tip 21 due to insufficient elongation of the high strength metal wire. No scratches or cracks on the surface, and low-temperature heat treatment after pressing removes localized stress generated by pressing and homogenizes, removes residual strain and repeats fatigue resistance This is because a high core wire 2 can be obtained.

If further supplemented, both the core wire tip portion 21 and the radiation transmitting material coil 32 are partially joined using the joining member 4 and the heat of fusion of the joining member 4 described later is utilized, so that after assembly. Even so, the tensile breaking strength of each metal element wire is improved, and concentrated stress and residual strain that are locally generated over the entire core wire tip 21 are simultaneously removed, so that the core wire 2 having high repeated bending fatigue resistance is formed. A guide wire 1A can be obtained.

And according to Tables 1-2, the low temperature heat treatment process of a predetermined condition is provided after a wire drawing process and a wire drawing process so that metal strands 1a-1h may be seen, and the wire drawing process and the low temperature heat treatment process are 1 A final wire drawing step is provided after repeating each step at least one set as a set, and when the total area reduction ratio until the final wire drawing step is 90.0% to 99.5%, The total increase rate of the tensile strength at break of the metal wire due to the low-temperature heat treatment is 12.1% to 32.1%, greatly exceeding 8%. Similarly, the total area reduction rate is 94.0%. When it is 99.5%, it is 12.1% to 32.1%. Similarly, when the total area reduction is 97.0% to 99.5%, it is 13.3% to 32.1% and 10%. It is shown above.
Further, the metal strand 1h having a wire diameter of 0.228 mm is a remelted material, which will be described later, of a SUS316 material containing 2 to 3% by weight of Mo with a solution-treated austenitic stainless steel wire. Primary by heating in a furnace using a heat treatment furnace at 180 ° C. to 525 ° C. for 10 minutes to 180 minutes after primary wire drawing using a wire diameter of 3.230 mm of a wire rod (bus wire) having a tensile breaking strength of 70 kgf / mm 2 Perform low-temperature heat treatment (in this embodiment, at 450 ° C. for 30 minutes), then perform secondary wire drawing, further perform secondary low-temperature heat treatment under the same conditions as the primary low-temperature heat treatment, and then perform tertiary wire drawing (this embodiment) In the example, the final wire drawing was performed, the total area reduction was 99.5%, the tensile strength at break was 400 kgf / mm @ 2, and the metal element was subjected to the third low temperature heat treatment under the same conditions as the first and second low temperature heat treatment. Line 1h is The tensile breaking strength is 424 kgf / mm @ 2, which is the highest value in each of the above examples. Accordingly, it is possible to ensure a total area reduction of 99.5% and a tensile breaking strength of 400 kgf / mm @ 2.
In this way, the drawing and low-temperature heat treatment are set as one set, and the number of times of setting is increased, and the tensile breaking strength of the metal strand can be improved to 450 kgf / mm @ 2 by using the manufacturing method described later.

The upper limit of the tensile breaking strength of the metal wire used for the core wire 2 is preferably 450 kgf / mm 2 or less, more preferably 400 kgf / mm 2 or less.
The reason for this is that, similarly to the provision of the upper limit of the total area reduction ratio of the wire drawing, the metal wire having a high strength tensile rupture strength is insufficient in elongation if the upper limit is exceeded. This is because cracking is likely to occur due to pressing when the cross-sectional shape of the tip 21 is a rectangular cross-section (FIG. 1, illustrated (D)), and pressing with a predetermined dimension becomes difficult.

In order to improve the tensile breaking strength of the metal wires used in each of the above-described examples in the production stage of the metal wires, the total area reduction (%) of the wire drawing is set to 90% or more as described above. In order to improve the tensile break strength of the metal strands in a temperature range where the tensile break strength increases steeply after the wire process, the wire drawing process and the low temperature heat treatment process are combined as a set. It may be repeated more than one set, but at least 1 set and 3 sets or less are desirable from the viewpoint of productivity and the like.

Next, the tensile fracture strength characteristics under low temperature heat treatment including the steel type difference of the austenitic stainless steel wire that has been subjected to strong wire drawing will be described below.

Fig. 3 shows that the austenitic stainless steel wire is generally used as the bus bar of the metal wire, and the metal wire after the final wire drawing with a total area reduction of 90% or more is pulled under the influence of heat (each temperature is 30 minutes). In the figure which shows the breaking strength characteristic, in the case of SUS304 material, illustration A is shown, and in the case of SUS316 material, illustration B is shown. According to this, SUS304 material begins to increase in tensile rupture strength due to the heat effect at 180 ° C and steeply slopes, and shows the highest tensile rupture strength property in the vicinity of 450 ° C. When the temperature exceeds 520 ° C., the tensile strength at break is lower than that at room temperature (20 ° C.). The SUS316 material containing Mo shows the same tendency as the SUS304 material on the low temperature side, but shows the highest tensile rupture strength characteristics at about 480 ° C. on the high temperature side, and the effect of improving the tensile rupture strength properties to 525 ° C. is remarkable. When the temperature exceeds 540 ° C., the tensile strength at break is lower than that at room temperature (20 ° C.).
The reason why the tensile strength at break is abruptly decreased is that, as described above, when the austenitic stainless steel wire subjected to the solution treatment is heated from 800 ° C. to 800 ° C., the carbon This requires energy for precipitation and migration of chromium, causing a sensitization phenomenon. In particular, in an ordinary SUS304 austenitic stainless steel wire having a carbon content of 0.08% or less, the temperature is about 700 ° C. for about 4 to 5 minutes. This is because a sensitization phenomenon appears and the tensile strength at break is extremely reduced.

Since it has such tensile breaking strength characteristics, the temperature range of the low-temperature heat treatment of the metal wire of SUS304 material is desirably a temperature range of 180 ° C. to 495 ° C. in which the tensile breaking strength increases sharply, and includes Mo. For example, the temperature range of the low-temperature heat treatment of the metal strand of SUS316 material (Mo is 2 wt% to 3 wt%) is preferably 180 ° C. to 525 ° C. The more preferable temperature range of the low-temperature heat treatment in the wire drawing of the metal strand is 300 ° C. to 495 ° C., and 300 ° C. to 525 for a metal strand of an austenitic stainless steel wire containing Mo. ° C. This is because the temperature range is such that a metal strand having a higher tensile breaking strength can be obtained. (Figure 3)
As described above, the present invention focuses on the tensile rupture strength characteristics depending on the temperature of the austenitic stainless steel wire having a high total area reduction rate after the strong wire drawing, and also on the temperature range suitable for the steel type difference. The present invention provides a new technical idea of a medical guide wire composed of the core wire 2 that has drastically improved the tensile strength at break by applying a low-temperature heat treatment to the metal wire of the core wire 2.

And the chemical component of the austenitic stainless steel wire of the metal strand used for each of these Examples is C: 0.15% or less, Si: 1% or less, Mn: 2% or less, Ni: 6% ~ 16%, Cr: 16% to 20%, P: 0.045% or less, S: 0.030% or less, Mo: 3% or less, the balance being iron and inevitable impurities. Thus, high strength austenitic stainless steel can be obtained by using the above method without using high silicon stainless steel (Si: 3.0% to 5.0%) or precipitation hardening stainless steel wire (SUS630 or the like). A metal wire of a steel wire can be obtained. C is preferably 0.005% or more for improving the tensile strength at break, and is preferably 0.15% or less from the viewpoint of suppressing intergranular corrosion.

The metal wire used for the core wire 2 of the present invention is an austenitic stainless steel wire having a wire diameter D7 of 0.228 mm to 0.457 mm, particularly when the tensile strength at break of the metal wire is 270 kgf / mm 2 or more, and the total area reduction rate. In order to facilitate the wire drawing process of 94% or more and to increase the rate of increase in tensile breaking strength by low-temperature heat treatment and to enable the thinning of 0.300 mm or less and to produce stably, a remelted material was used. SUS304 material or SUS316 material is desirable.
The reason for this is that the cause of disconnection when drawing a stainless steel wire is most often oxide inclusions as well as surface flaws, and this tendency becomes more pronounced as the wire becomes thinner.
And the chemical component is low in the components of Al, Ti, Ca, O, which are inclusion generation elements, and also suppresses S that causes a reduction in wire drawing due to the action of sulfide. The specific chemical components of the austenitic stainless steel wire are, by weight, C: 0.08% or less, Si: 0.10% or less, Mn: 2% or less, P: 0.045% or less, S: 0 0.010% or less, Ni: 8% to 12%, Cr: 16% to 20%, Mo: 3% or less, Al: 0.0020% or less, Ti: 0.10% or less, Ca: 0.005% or less , O: 0.0020% or less, with the balance being Fe and inevitable impurities.
And as a manufacturing method of a remelting material, it is the manufacturing method etc. of the electroslag remelting which used the flux for the ingot after melting of stainless steel. Even when a triple melting material is used, the same effect as described above can be obtained.

As described with reference to FIGS. 2 and 3, the austenitic stainless steel wire that has been subjected to strong wire drawing (total reduction in area of 90% or more) has a characteristic that tensile fracture strength is improved by low-temperature heat treatment. Therefore, in order to improve the tensile strength at break, for example, the temperature range of the low-temperature heat treatment in the case of SUS304 material is desirably 180 ° C. to 495 ° C., which is a temperature range in which the tensile strength at break increases sharply, and Mo is added. The temperature range of the low-temperature heat treatment of, for example, SUS316 material (Mo is 2 wt% to 3 wt%) is preferably 180 ° C. to 525 ° C.

And in Tables 1-3, after drawing at least one set of wire drawing and low-temperature heat treatment after wire drawing, the final wire drawing is provided, and the total area reduction until the final wire drawing is changed from 90% to 99.5%. The metal wires 1b, 1d, 1f, 1h, and comparative examples of the examples in which the core wire made of the metal wires is subjected to low-temperature heat treatment after the final wire drawing will be described below.

The metal strands 1b, 1d, 1f, and 1h in which the total area reduction rate of each example used for the core wires in Tables 1 to 3 is 90% or more are given by assuming that the total area reduction rate is X (%). The relational expression with the tensile breaking strength Y (kgf / mm @ 2) is (1) below.
Relational expression: 450 ≧ Y ≧ 2.000X + 70 (1)
In the relational expression (1), for example, the total area reduction ratio X of the metal strand 1b is 90%, so that the tensile breaking strength Y is 250 kgf / mm 2 or more and 450 kgf / mm 2 or less, and the tensile breaking strength of the metal strand 1b is The strength is 257 kgf / mm @ 2 and satisfies the relational expression (1). Similarly, the other embodiments also satisfy the relational expression (1). Also, the total increase rate of tensile breaking strength by low-temperature heat treatment until the final drawing (secondary drawing or tertiary drawing) of the metal strands 1b, 1d, 1f, and 1h is 12.1% to 32.1% And both are 8% or more.
However, Comparative Example 2 does not satisfy the relational expression (1), and the total increase rate of the tensile fracture strength of the low-temperature heat treatment up to the final wire drawing is 3.2%, which is much lower than 8%.

In addition, after supplementarily joining the core wire 2 and the radiation transmissive material coil 32 using the joining member 4 using the metal element wire, the tip of the radiation transmissive material coil 32 is pressed. The core wire tip 21 is subjected to low-temperature heat treatment at 180 ° C. to 495 ° C., or when the core wire is an austenitic stainless steel wire containing Mo, by performing low-temperature heat treatment at 180 ° C. to 525 ° C. The guide wire having a high resistance to repeated bending fatigue is obtained by improving the tensile breaking strength of the portion 21 and further removing the concentrated stress and residual strain generated in the ground wire tip portion 21 subjected to grinding and pressing. be able to.
This is apparent when, for example, the metal strands 1a and 1b, 1c and 1d, and the like are compared. In addition, the method of carrying out the low temperature heat processing of the core wire front-end | tip part 21 in the radiation transparent material coil 32 is the low temperature heating using the heat processing furnace in the temperature range suitable for the said steel grade corresponding with the temperature range where tensile fracture strength increases steeply. A low-temperature heat treatment using bright heat treatment in an inert gas, a low-temperature heat treatment by high-frequency current heating, and a low-temperature heat treatment by using the fusion heat of the joining member 4 described later.

Next, from Tables 1 to 3 and FIG. 3, the temperature range in which the tensile breaking strength of the metal strand increases more steeply (from 300 ° C. to 495 ° C., or when the metal strand is an austenitic stainless steel wire containing Mo) The metal strands 1d, 1f, and 1h, which are subjected to low-temperature heat treatment at 300 to 525 ° C. and have a total area reduction rate of 90% or more, are as follows: The relational expression with the breaking strength Y (kgf / mm) is the following (2).
Relational expression: 450 ≧ Y ≧ 2.150X + 70 (2)
In the relational expression (2), for example, the primary and secondary low-temperature heat treatment of the metal wire 1d is in the temperature range of 300 ° C. to 525 ° C. (example is 420 ° C., 75 minutes), and the total area reduction rate X is Therefore, the tensile breaking strength Y is 272.1 kgf / mm 2 or more and 450 kgf / mm 2 or less, and the tensile breaking strength of the metal wire 1d is 280 kgf / mm 2 and satisfies the relational expression (2). Other examples also satisfy the relational expression (2). Moreover, the total increase rate of the tensile fracture strength by the low-temperature heat treatment until the final drawing (secondary drawing or tertiary drawing) of the metal strands 1d, 1f, and 1h is 12.6% to 32.1%, Both are 10% or more.
However, Comparative Example 2 does not satisfy the relational expression (2), and the total increase rate of the tensile fracture strength of the low-temperature heat treatment until the final wire drawing is 3.2%, which is significantly lower than 10%.

Next, of the metal strands in Tables 1 to 3, the metal strands 1d, 1f, and 1h having a total area reduction rate of 94.0% to 99.5% are assumed to have a total area reduction rate of X (%). The relational expression with the tensile breaking strength Y (kgf / mm @ 2) of the metal wire is as follows (3).
Relational expression: 450 ≧ Y ≧ 2.200X + 70 (3)
In the relational expression (3), for example, the total area reduction ratio X of the metal wire 1d is 94.0%, so that the tensile strength at break Y is 276.8 kgf / mm 2 or more and 450 kgf / mm 2 or less. The tensile fracture strength of 1d is 280 kgf / mm @ 2 and satisfies the relational expression (3). Similarly, the other examples also satisfy the relational expression (3). Moreover, the total increase rate of the tensile fracture strength by the low-temperature heat treatment until the final drawing (secondary drawing or tertiary drawing) of the metal strands 1d, 1f, and 1h is 12.6% to 32.1%, Both are 10% or more.
However, Comparative Example 2 does not satisfy the relational expression (3) as described above.

Next, of the metal strands in Tables 2 to 3, the metal strands 1f and 1h having a total area reduction rate of 97.0% to 99.5% are assumed to be X (%). The relational expression with the tensile breaking strength Y (kgf / mm @ 2) of the strand is as follows (4).
Relational expression: 450 ≧ Y ≧ 2.300X + 70 (4)
In the relational expression (4), for example, the total area reduction ratio X of the metal wire 1f is 97.0%, so that the tensile strength at break Y is 293.1 kgf / mm 2 or more and 450 kgf / mm 2 or less, and the metal strand The tensile breaking strength of 1f is 321 kgf / mm @ 2 and satisfies the relational expression (4). Similarly, the other examples also satisfy the relational expression (4). In addition, the total increase rate of tensile breaking strength by low-temperature heat treatment until the final drawing (secondary drawing or tertiary drawing) of the metal strands 1f and 1h was changed from 13.3% to 32.1%. 10% or more.
However, Comparative Example 2 does not satisfy the relational expression (3) as described above.

In addition, in addition, the method in which the core wire 2 and the radiation transmitting material coil 32 are partially bonded using the bonding member 4 and then the core wire tip 21 in the radiation transmitting material coil 32 is subjected to low temperature heat treatment is described above. This is the same as described in the relational expression (1) for the strands.

Next, FIG. 4 shows the relationship between the tensile breaking strength Y (kgf / mm @ 2) of the metal wire and the total area reduction ratio X (%). In the figure, symbol i represents relational expression (1), code b represents relational expression (2), code c represents relational expression (3), code d represents relational expression (4), and code ho represents a comparative example. Reference numeral 1 indicates a comparative example 2 for the reference numerals.

Next, “twisting under low-temperature heat treatment” or “low-temperature heat treatment after twisting” was performed on the core wire 2 made of a metal wire having a predetermined total area reduction after the final wire drawing. Regarding the tensile breaking strength and bending residual angle of the core wire 2 at that time, an example of “twisting under low temperature heat treatment using electrical resistance heating as the low temperature heat treatment” will be described below.

FIG. 8 shows that the temperature of the core wire 2 (metal wire 1c) is from 180 ° C. to 495 ° C. for 30 seconds to 180 minutes (in this embodiment, 450 ° C. for 3 minutes) using the metal wire 1c of the above embodiment. FIG. 9 shows the upper and lower limits of the tensile breaking strength when the number of twists is changed under low-temperature heat treatment using electric resistance heating, including variations of 50 samples. As in FIG. 8, bending is performed when the temperature of the core wire 2 (metal wire 1 c) is changed in the number of twists under a low-temperature heat treatment using electric resistance heating as described above, using the metal wire 1 c. The range of the upper and lower limits of the residual bending angle after the test including the variation of 50 samples each is shown. The bending residual angle after the bending test mentioned here means that the core wire 2 is bent 180 degrees into a round bar having an outer diameter of 15 mm, a load of 500 g is held for 20 seconds, the load is released, and the long axis of the core wire 2 is released. It refers to the residual angle with respect to the direction, that is, the tilt angle that is plastically deformed.

According to FIGS. 8 and 9, the tensile fracture strength has a relatively small fluctuation range when the number of twists is between 100 times / m and 275 times / m, and the fluctuation range becomes large when deviating from this range, that is, stable quality. You will not be able to get. In addition, the bending residual angle is small when the number of twists is between 100 times / m and 275 times / m, and if the deviation is outside this range, the fluctuation range becomes large. The reason for this is that when the rotation speed is less than 100 turns / m, the number of twists is insufficient, and the inhomogeneous portion remains in the major axis direction of the core wire 2, and conversely, when it exceeds 275 times / m to 325 times / m, Because it is considered that a slip line (Ludders line) with an inclination of approximately 45 degrees in the major axis direction of the core wire is generated, and an inhomogeneous portion due to the over twist is locally scattered. is there. Therefore, the twisting of the present invention does not mean an overtwisting in which the slip line is generated.
The residual bending angle becomes the smallest and stable between 100 times / m and 200 times / m, more preferably from 120 times / m to 180 times / m, and even more preferably from 10% of the number of twists. It is desirable to reverse twist 30%, and most preferably 15% to 25%. Specifically, for example, after twisting in one direction at 120 times / m, twisting is performed in the reverse direction from 12 times / m to 36 times / m, most preferably from 18 times / m to 30 times / m. . The reason why this is desirable is that the stress in the twist direction of the strong work twist is reversed by the reverse twist after the strong work twist in one direction, and the effect of low-temperature heat treatment is increased by releasing the twist temporarily to reverse the twist. It is because it is thought that the core wire 2 with high property and rotation transmission property can be obtained.

FIG. 10 is an apparatus diagram for performing twisting and electrical resistance heating on the core wire 2 using the metal element wire. The core wire 2 is passed from the bobbin 13 around which the core wire 2 is wound into the heat retaining case 16 through the feed roller 14A, and the core wire 2 is fixed by the rotary chuck 9 and the fixed chuck 10 that can move in the long axis direction of the core wire 2. The core wire 2 is twisted in a predetermined amount in one direction or in the reverse direction by the rotary chuck 9 while the core wire 2 is fixed by the fixed chuck 10 which can be energized by the current generator 8 and loaded with the weight 12. Let Specifically, when the outer diameter of the core wire 2 is 0.340 mm and the fixed span between the chucks 9 and 10 (L in the drawing) is 4000 mm, the weight 12 is loaded on the core wire 2 in one direction from 400 to 800 times. Perform twisting. More preferably, 10 to 30% of the number of twists is applied in the reverse direction, that is, 40 to 240 times.
Then, after twisting under a low temperature heat treatment by electric resistance heating, the core wire 2 is unfixed from the rotary chuck 9 and the fixed chuck 10, and the core wire 2 is shown on the left side in the drawing by the feed rollers 14A and 14B. The core wire 2 having excellent linearity and rotational transmission can be obtained continuously by repeating this process thereafter. The electrical resistance heating may be performed by energizing the core wire 2 and gradually increasing the temperature as the number of twists increases.

That is, in this process, the core wire 2 wound around the bobbin 13 is sent out into the heat retaining case 16 by electric resistance heating through the feed rollers 14A and 14B (the left side in the figure), and the core wire 2 after feeding is fixed to the rotary chuck 9 A step of fixing with the chuck 10, a step of releasing the stopper 17 of the fixed chuck 10 to which the weight 12 is connected and making the fixed chuck 10 movable in the long axis direction and applying a load (weight 12) to the core wire 2; A step of applying current by applying current to the core wire 2 in the heat retaining case 16 kept at a constant temperature by the current generator 8, and a step of twisting a predetermined amount in a predetermined direction by the rotary chuck 9 while being energized, or During the constant twisting process, the temperature is gradually changed and the current is applied to the core wire 2 by the current generator 8, and the fixing of the core wire 2 of the fixed chuck 10 is released. In order to prevent the movement to the side of the weight 12 (right side in the figure) due to rotation, after the stopper 17 is actuated after twisting, the process of releasing the fixation of the core wire 2 between the rotary chuck 9 and the fixed chuck 10, and the feed roller 14A, 14B includes a step of feeding the core wire 2 (left side in the figure) and a step of cutting the core wire 2 with a cutting blade 15 after feeding the core wire 2 by a predetermined amount. It is the process which can produce 2 continuously. Alternatively, the core wire 2 may be preliminarily cut to a predetermined length and fixed with each chuck, and the twisting process similar to the above may be performed under a low temperature heat treatment by electric resistance heating.

The temperature of the low-temperature heat treatment by electric resistance heating is such that the temperature of the core wire 2 is 300 ° C. to 495 ° C., the heating time is 30 seconds to 180 minutes (450 ° C., 3 minutes in this embodiment), or the core wire is In the case of an austenitic stainless steel wire, the heating time is 300 ° C. to 525 ° C., and the heating time is 30 seconds to 180 minutes (450 ° C., 3 minutes in this embodiment). Further, the weight 12 is preferably 5% to 30%, more preferably 8% to 27% of the tensile breaking force of the core wire 2 using the metal element wire before the twisting after the final wire drawing step, and more preferably Is from 10% to 24%.
Specifically, in the case of the metal strand 1f, since the wire diameter is 0.228 mm and the tensile breaking strength before twisting after the final wire drawing step (secondary wire drawing) is 296 kgf / mm 2, The tensile breaking force of the core wire 2 using the wire 1f is 12.08 kgf (π × 0.228 × 296/4), and the weight 12 is preferably 2.42 kgf (20%).
And if it deviates from the range of 5% to 30%, undulation occurs when the weight 12 is light, and breakage occurs during twisting when the weight 12 is heavy, so that the core wire 2 having excellent linearity can be obtained. In addition, productivity cannot be increased. That is, it is important to change the weight of the weight 12 in accordance with the tensile breaking force due to the tensile breaking strength before twisting of the core wire 2.
As described above, the electrical resistance heating and twisting conditions are low-temperature heat treatment conditions by electrical resistance heating at 380 ° C. to 495 ° C. for 30 seconds to 180 minutes, and the number of twists is 100 times / m to 275 times / m. And preferably 100 times / m to 200 times / m, more preferably 120 times / m to 180 times / m, and still more preferably 10% to 30% of the number of twists in the reverse direction, and weight 12 Is preferably 5% to 30% of the tensile breaking force of the core wire 2 before twisting.

And the optimum condition with high linearity and rotation transmission was found in the relation between the number of twists and the applied load (weight). In FIG. 11, the ratio of the load W (kgw) to the tensile breaking force P (kgf) before twisting of the core wire on the horizontal axis is the load ratio X (%), and the load ratio X (%) is W ÷ P. The relationship of × 100 is shown, the number of twists N (times / m) is shown on the vertical axis, and the range surrounded by the reference symbols A and C is the condition for obtaining a high degree of linearity, and further surrounded by the reference symbols B and C The range is more preferable conditions.
An inclination line (indicated by the symbol a) shown in the upper limit of the number of twists is expressed by a mathematical expression. Since this is / m, this inclination line (indicated by symbol a) can be expressed by the following relational expression (5). Similarly, when the slope line of the lower limit range (symbol C) is expressed by a mathematical formula, the load weight ratio is 5% and the number of twists is 120 times / m, and the load ratio is 30% and the number of twists is 100 times / m. Therefore, this inclination line (indicated by symbol a) can be represented by the following relational expression (6).
Relational expression: N = −1.8X + 284 (5)
Relational expression: N = −0.8X + 124 (6)
The number of twists N (times / m) for obtaining a core wire having a high degree of linearity and rotation transmission from the two relational expressions (5) and (6) in the upper and lower limit range is expressed by the following relational expression (7). It is necessary to satisfy.
Relational expression: −0.8X + 124 ≦ N ≦ −1.8X + 284 (7)
N: Number of twists (times / m)
X: Load ratio (%)

Further, since the symbol B in the figure is a load weight ratio of 5% and the number of twists is 250 times / m, and the load ratio is 30% and the number of twists is 180 times / m, (B) can be represented by the following relational expression (8), and the lower limit range of the slope line (symbol C) can be represented by the relational expression (8).
Relational expression: N = −2.8X + 264 (8)
Since the preferable upper and lower limit range is a range surrounded by the reference symbols B and C, the number of twists for obtaining a core wire having a preferable high linearity satisfies the following relational expression (9). Is required.
Relational expression: −0.8X + 124 ≦ N ≦ −2.8X + 264 (9)

If the number of twists N (turns / m) is within a range satisfying the relational expression (7), when the core wire is rolled from the higher side to the lower side by providing a certain angle, the rotation of both ends of the core wire is performed. There is no meandering or swell rotation in synchronism, and each time the core wire rolls, a speed difference occurs in the rotation of both ends, the slope gradually increases, and when it reaches the lowest position, it reaches the lowest position. Either one does not reach quickly, but can reach almost the same time to obtain a core wire with a high degree of linearity. Further, a range satisfying the relational expression (9) is more preferable.
By satisfying all of these conditions, it satisfies the quality required for medical guidewires, such as high strength tensile strength at break, high linearity with few residual angles, and high rotational transmission to the tip side. Can be made.
In addition, although Patent Document 3 describes twisting by overtwisting, the present invention does not mean overtwisting, and Patent Document 3 describes the number of twists and load. No correlation has been analyzed for the correlation with the load ratio.

And in the said Example, although the "twisting process under low-temperature heat processing" using electrical resistance heating as low-temperature heat processing was demonstrated, as low-temperature heat processing other than electrical resistance heating, the heat processing furnace which incorporated the heater Any of a low-temperature heat treatment using a heat treatment, a low-temperature heat treatment of bright heat treatment in an inert gas, or a low-temperature heat treatment by high-frequency current heating may be used.
Also, “twisting under low temperature heat treatment” here means “twisting with the core wire heated to a predetermined temperature” or “twisting after starting twisting at room temperature” In any case, the twisting process is performed by gradually increasing the temperature of the core wire to a predetermined temperature.
And the above-mentioned “twisting with the core wire heated to a predetermined temperature” suppresses the disconnection at the time of twisting with a core wire having a higher degree of processing (total surface reduction rate is 94% to 99.5%). In addition, the above-mentioned “twisting by gradually changing temperature rise in which the core wire is heated to a predetermined temperature while being twisted after starting twisting at normal temperature” is performed by twisting in a cold state. Promotes refinement of core crystal grains, has high tensile fracture strength, and gradually removes residual stress that increases locally as the number of twists increases. It is possible to obtain a core wire having a high degree of linearity by homogenizing the inhomogeneity of the hardness distribution of the part within a certain range.

In addition, “low temperature heat treatment after twisting of the core wire” may be performed, and the above “low temperature heat treatment after twisting of the core wire” has a poor effect of preventing the breakage of the core wire during twisting. This is desirable in terms of obtaining a core wire having a high breaking strength.
The reason for this is that the twisting process is performed at room temperature, that is, in the cold state, thereby further promoting the refinement of the crystal grains as compared with the twisting process in the hot state. This is because a core wire with higher tensile fracture strength can be obtained by suppressing the growth and removing the locally generated residual stress.
Therefore, the “twisting under the low-temperature heat treatment” is preferably performed when the total area reduction of the core wire is high (the total area reduction is 94% or more and 99.5% or less). The “low temperature heat treatment” is preferably performed when the total area reduction of the core wire is relatively low (the total area reduction is 90% or more and 97% or less). Which one to select is determined by the priority properties (tensile breaking strength, linearity, rotational transmission, etc.) required for the guide wire.

Next, FIG. 5 shows a guide wire 1B of another embodiment 2, and the core wire 2 uses the metal strands 1a to 1h described in the embodiment 1A, and differs from the embodiment 1. The intermediate joints 411, 412, 413,... 10 structures (for example, 90 mm in length) are arranged at equal intervals (indicated by C in the figure).
With this configuration, the core wire 2 is made of a metal wire having a high tensile breaking strength, and there is no bending flaw on the distal end side when bent at a lesion, and the guide has improved repeated bending fatigue resistance. Wire 1B can be obtained.
In addition, in this structure, a joining member 4 made of a radiopaque material (Table 4, which will be described later, reference numeral A-1 and the like) is used, and intermediate joining portions (reference numeral 411) at a plurality of locations of the radiation transmitting material coil 32 are provided. , 412, 413,...)), It is possible to have a function as a length measuring measure that enables measurement of the stenotic lesion length. The intermediate joints 411, 412, 413,... Can be measured in any length as long as they have regular predetermined intervals such as an equal interval, a difference series, and a geometric series. Function as.

And if it supplements, the length of the coil wire end part 21 and the coil wire of the radiation transparent material coil 32 will be utilized by making use of the fusion heat at the time of joining of the joining member 4 which will be described later, by arranging the joining parts at a plurality of locations. It is possible to obtain the same effect as the low-temperature heat treatment on the core wire tip 21 and the entire coil body 3 over the position, and as a result, the tensile breaking strength characteristic of the core wire tip 21 can be enhanced over the long position, And the resistance to repeated bending fatigue of the core wire tip 21 can be improved.
And by this method, even if it does not use the heat treatment furnace which heats the whole, the tensile breaking strength characteristic of each metal strand of the core wire 2 is improved partially and in arbitrary desired positions, and especially bending stress is excessive. It is possible to obtain a guide wire that simultaneously improves the resistance to repeated bending fatigue of the core wire 2 of the joined portion that is easily applied.

Next, FIG. 6 shows a guide wire 1C of another embodiment 3, and the metal wires of the core wire 2 are the same as the metal wires 1a to 1h described in the embodiment 1A, and The core wire 2 is formed in the form of a coil body 321 formed by twisting a plurality of thin wires using the same material as the coil wire of the radiation transmitting material coil 32 having a predetermined length (for example, about 900 mm to about 2400 mm) on the outer peripheral portion on the hand side. The length of the tip portion of about 300 mm is the same as that of the first embodiment in FIG.
FIG. 7 shows a guide wire 1D according to another embodiment 4 in which a single or a plurality of short radiopaque material coils 31 or radiopaque material coils 322 are provided at the distal end portion of the core wire 2 at a predetermined interval. The end portion of the radiopaque material coil 31 or the radiopaque material coil 322 is joined to the core wire 2 using a wire, and the resin coating 6 is formed on the outer periphery thereof, and the core wire 2 is in direct contact with the resin coating 6 Indicates the structure. In addition, the metal strand of the core wire 2 uses the same material which passed through the manufacturing process similar to the said metal strand 1a-1h.

Even in such a structure, by using the metal wires 1a to 1h described in the guide wire 1A of the first embodiment for the core wire 2, the tensile breaking strength is high, and high linearity and rotational transmission are provided. Guide wires 1C and 1D having high resistance to repeated bending fatigue can be obtained.

Next, a method for manufacturing a guide wire composed of the core wire 2 using a metal wire having a high tensile breaking strength and a high degree of linearity / rotational transmission will be described below.

A medical wire in which a core wire made of a flexible elongated body and a coil spring body having the core wire inserted through the tip of the core wire are attached, and the core wire and the coil spring body are partially joined using a joining member. In the guide wire manufacturing method,
The core wire is made of a metal wire,
The metal element wire is a solution-treated austenitic stainless steel wire, and after the wire drawing step and the low-temperature heat treatment after the wire drawing step are repeated as at least one set, a final wire drawing step is provided.
The total area reduction until the final wire drawing step is 90% to 99.5%,
When the low-temperature heat treatment step is 180 to 495 ° C. for 10 to 180 minutes, or when the metal strand is an austenitic stainless steel wire containing Mo, the temperature is 180 to 525 ° C. for 10 to 180 minutes,
The total increase rate of the tensile breaking strength of the metal strand by the low-temperature heat treatment step until the final wire drawing step is 8% or more,
Then, when the temperature of the metal strand is 180 ° C. to 495 ° C. for 30 seconds to 180 minutes, or when the metal strand is an austenitic stainless steel wire containing Mo, Under a low-temperature heat treatment process at 180 to 525 ° C. for 30 seconds to 180 minutes,
With one end of the metal wire being subjected to a load load of 5% to 30% of the tensile breaking force of the metal wire before twisting, the other end is twisted from 100 times / m to 275 times / m. As the processing step, the twisting step under the low-temperature heat treatment,
When the tensile strength at break of the metal wire is Y (kgf / mm @ 2) and the total area reduction is X (%),
Satisfies the relational expression of 450 ≧ Y ≧ 2.000X + 70,
A medical guide wire manufacturing method comprising the core wire using the metal element wire.

Here, in the low-temperature heat treatment step in the wire drawing process of the metal wire, the temperature and time are set as the above conditions because the temperature range is the same as that in FIG. It is a temperature range suitable for steel grades where the tensile breaking strength of the wire increases steeply, and if the heating time is less than 10 minutes, the effect of improving the tensile breaking strength is poor, and if it exceeds 180 minutes, the effect of further improvement cannot be expected. From the viewpoint of economy and productivity.
Further, five sets or more may be provided as one set of the wire drawing step and the low-temperature heat treatment step, but it is the same as described above that three sets or less are desirable from the viewpoint of economy, productivity, and the like.
In addition, when the core wire made of the metal wire after the final wire drawing step is at a low temperature heat treatment step of 180 ° C. to 495 ° C. for 30 seconds to 180 minutes, or when the core wire is an austenitic stainless steel wire containing Mo The reason why the temperature is changed from 180 ° C. to 525 ° C. for 30 seconds to 180 minutes is the same reason as in the low-temperature heat treatment step in the wire drawing step.
With this configuration, the total area reduction rate is reduced by twisting the core wire after the final wire drawing under a predetermined condition under a low temperature heat treatment suitable for a steel type in a temperature range where the tensile breaking strength increases steeply. Prevents breakage in the twisting process of high-strength core wire, homogenizes the hardness distribution of the surface layer and inner layer of the core wire with extremely low inhomogeneity, high tensile breaking strength, linearity and rotation A medical guide wire made of a core wire with improved transmissibility can be manufactured.

And in the manufacturing method of the medical guide wire as described above,
The other end of the metal wire after the final wire drawing step is subjected to a load load of 5% to 30% of the tensile breaking force of the metal wire before twisting to one end of the metal wire. Is a twisting process of 100 times / m to 275 times / m,
Thereafter, the temperature of the metal strand is 180 ° C. to 495 ° C. for 30 seconds to 180 minutes, or when the metal strand is an austenitic stainless steel wire containing Mo, 180 ° C. to 525 ° C. for 30 seconds to 180 minutes. The medical guide wire manufacturing method is characterized in that the low-temperature heat treatment step is the low-temperature heat treatment step after the twisting step, and the core wire using the metal strand is used.
Here, in the low temperature heat treatment process of the core wire, the temperature of the metal strand is 180 ° C. to 495 ° C. for 30 seconds to 180 minutes, or when the metal strand is an austenitic stainless steel wire containing Mo, the temperature is 180 ° C. to 525 ° C. The temperature range from 30 seconds to 180 minutes is a temperature range suitable for a steel type in which the tensile rupture strength of the core wire in the strong wire drawing in FIG. If it is less than 30 seconds, the linearity effect by twisting is poor, and if it exceeds 180 minutes, the effect of further improving the linearity / rotational transferability cannot be expected, from the viewpoint of economy and productivity.
With this configuration, it is possible to perform the twisting process in the cold state rather than performing the twisting process in the hot state, particularly by performing the low-temperature heat treatment process after the twisting process. It is made of a core wire with higher linearity and rotational transmission and higher tensile breaking strength by adopting a low-temperature heat treatment process suitable for the steel type in a temperature range where the tensile breaking strength increases sharply thereafter. A medical guidewire can be manufactured.

In addition, in the method for manufacturing the medical guide wire described above,
The low-temperature heat treatment step in the twisting step under the low-temperature heat treatment step or the low-temperature heat treatment step after the twisting step is performed on the metal wire after the final wire drawing step, Electric resistance heating when the temperature of the metal strand is 300 ° C. to 495 ° C. for 30 seconds to 180 minutes, or when the metal strand is an austenitic stainless steel wire containing Mo, 300 ° C. to 525 ° C. for 30 seconds to 180 minutes age,
In the state in which the twisting step is applied with a load load of 5% to 30% of the tensile breaking force of the metal strand before twisting to one end of the metal strand, the other end is started from 100 times / m. A twisting process of 200 times / m,
A medical guide wire manufacturing method comprising the core wire using the metal element wire.
Here, the temperature range of the metal element wire in the low-temperature heat treatment process of the metal element wire is that the tensile breaking strength of the metal element wire in the strong wire drawing process in FIG. The temperature range is suitable for steel grades with increasing inclination, and electrical resistance heating is performed by twisting by heating uniformly to the inner layer even if the hardness distribution of the surface layer and inner layer of the core wire is inhomogeneous. The reason why the twisting condition is used is that in FIG. 8 and FIG. 9 described above, it is possible to obtain a core wire with less residual angle and high linearity / rotational transmission.
With this configuration, the low-temperature heat treatment process is a low-temperature heat treatment condition suitable for the steel type in a temperature range where the tensile breaking strength of the core wire increases more steeply, and the twisting process has a hardness distribution of the surface layer portion and the inner layer portion of the core wire. By adopting the twisting process conditions that homogenize with extremely little inhomogeneity, the core wire has extremely high linearity and rotational transmission, no bending at the tip, and further improved resistance to repeated bending fatigue. A medical guide wire made of a core wire can be manufactured.

In addition, in the method for manufacturing a medical guide wire as described above,
The twisting process in the twisting process under the low-temperature heat treatment process or the low-temperature heat treatment process after the twisting process on the metal wire after the final wire drawing process,
Twist the other end with load applied to one end of the metal strand,
The ratio of the load weight W (kgw) to the tensile breaking force P (kgf) before twisting of the metal element wire is defined as a load weight ratio X (%), and the load weight ratio X (%) is W ÷ P × 100. In the case of the relationship, the number of twists N (times / m) is
-0.8X + 124 ≦ N ≦ −1.8X + 284 is satisfied,
A medical guide wire manufacturing method comprising the core wire using the metal element wire.
More preferably, the method for producing a medical guidewire according to the above description,
The twisting process is to twist the other end with a load applied to one end of the metal wire,
The ratio of the load weight W (kgw) to the tensile breaking force P (kgf) before twisting of the metal element wire is defined as a load weight ratio X (%), and the load weight ratio X (%) is W ÷ P × 100. In the case of the relationship, the number of twists N (times / m) is
−0.8X + 124 ≦ N ≦ −2.8X + 264 is satisfied,
A medical guide wire manufacturing method comprising the core wire using the metal element wire.
With this configuration, in the “twisting process step under low-temperature heat treatment” or “low-temperature heat treatment process after the twisting process step”, the correlation between the load load and the number of twists in the twisting process step is clarified, A medical guide wire using a core wire having a high degree of linearity / rotational transferability and a high tensile breaking strength characteristic can be manufactured.

Next, an example of an assembly of a suitable treatment tool in a stenotic lesion using the guide wires 1 (reference numerals 1A to 1D) of Examples 1 to 5 will be described below.

FIG. 12 shows a progress diagram of the guide wire 1 to the stenotic lesion in the treatment of the vascular stenosis lesion of the lower limb. For example, in order to quickly reach the obstruction lesion 90C of the anterior tibial artery 90B, Even in a state where the distal portion of the guide wire 1 is bent in a U shape (reference symbol (B) in the drawing (B)), the portion of the generally straight superficial femoral artery 90A with few bending meanders is bent to the branch portion 90D. The guide wire 1 is then guided to the occluded lesioned part 90C after it is pulled to the proximal side once to make it straight (symbol S1). (Code S2)

In such a case, the metal wire of the core wire 2 of the guide wire 1 of the present invention is strongly processed to increase the tensile breaking strength, and has a high degree of linearity and rotational transmission. There is a special effect that can increase the restoring force of a straight shape without attaching. The outer diameter (D1, D2) of the coil body 3 of the guide wire 1 and the outer diameter (D6) of the leading plug 5 in the treatment of the vascular lesion part of the lower limb are approximately 0.457 mm (0.018 inch), and As an assembly with the guide wire 1, a hollow multi-filament having an irregular shape on the outer peripheral portion as a structure that strongly supports a reaction force that penetrates the guide wire 1 and advances the guide wire. A microcatheter 100 having a coil body structure is used.
Further, using the guiding catheter 110 having an inner diameter of 1.91 mm to 2.67 mm as a structure for inserting both the guide wire 1 and the microcatheter 100 and supporting both reaction forces at the same time, An assembly of the guide wire 1, the microcatheter 100, and the guiding catheter 110 is an example of a suitable treatment tool assembly.

Further, by using the guide wire 1 of the present invention comprising the core wire 2 using a metal wire with improved tensile strength and high linearity and rotational transmission, the guide wire for cardiovascular treatment can be thinned. Diameter can be achieved. For example, the outer diameter of the coil body 3 of the guide wire 1 can be reduced from 0.355 mm to 0.228 mm (0.014 inch to 0.009 inch).
Then, the guide wire 1 is inserted into the microcatheter 100, and the guide wire 1 and the micro catheter 100 are inserted into the guiding catheter 110. In such a case, following the narrowing of the guide wire 1, the guiding catheter 110 is changed from 7F to 8F to 6F (inner diameter 2.3 mm to 2.7 mm to inner diameter 1.91 mm to 2.00 mm). The diameter of the microcatheter 100 (with an inner diameter of 0.28 mm to an inner diameter of 0.90 mm) can be reduced.
In addition, the lower limb vascular treatment guide wire has a large vascular diameter of approximately 2 to 5 times the cardiovascular diameter and a stenotic lesion length of more than 3 times. Force is required, and the outer diameter (D1, D2, D6, D7) is approximately 0.457 mm (0.018 inch), and in order to obtain an advancing force that is strongly pushed forward, Power is needed.

The microcatheter 100 that receives the reaction force that supports this strongly advancing force includes a multilayer resin tube (inner layer PTFE, outer layer polyamide, etc.) structure, and a structure in which a braid of metal wires is interposed in the multilayer resin tube body. In addition, the tip portion 100B having a substantially conical shape made of a metal or a synthetic resin is fixed, and a plurality of metal wire round wires are formed into a multi-strand coil body, It is desirable to use a flexible hollow tube made of the above-mentioned spiral tube body provided with a metal tip that can be perforated, or a tapered cone-shaped resin tip having high penetration into a bent meandering lesion. .

Furthermore, in the case of cardiovascular treatment procedures, the vessel diameter is small and the meandering is severe, and in the case of lower limb vessel treatment procedures, the vessel diameter is thick but stenosis or completely occluded lesion length is longer than that of cardiovascular. In order to perforate the closed portion with the guide wire 1 in a length of three times or more, the spiral strip of a multi-strand coil body using a round wire of a metal wire whose outer peripheral portion forms a rounded irregular shape. As shown in FIG. 13, the body is more desirable, and among the multiple filaments, for example, one or two thick lines 100C having a diameter of 0.11 to 0.18 mm and a diameter of 0.06 mm are used. 0.10 mm fine wire 100D is formed by winding or twisting 2 to 8 wires, or two or more fine wires are set as one set with respect to one thick wire, and each metal wire is adjacent to each other. In contact with winding or twisting composition The outer peripheral portion at Jo has the structure of the corrugated spiral strip tube 100A.

The reason for using the spiral tubular body 100A is that the blood vessel wall and the convex and concave portions of the outer peripheral portion of the multi-filament are in contact with each other to prevent sliding movement, and the force that supports the reaction force of the guide wire 1 to be pushed forward is high. Yes, it also has the ability to perforate within the lesion, and the thick line comes into contact with the blood vessel wall faster, and if it rotates once in that state, it moves only with the twisted pitch of the thick line, and the travel distance per rotation is longer. As a result, the advance / retreat operation of the assembly including the guide wire 1 is accelerated. In addition, at least a part of the outer peripheral portion (within 300 mm from the distal end) due to the external compression or pressing action of the blood vessel wall or the like during insertion into the blood vessel wall or the like during the insertion into the blood vessel at the distal end portion of the outer peripheral portion or the entire structure If it is the structure which forms the said unevenness | corrugation, the flexible hollow tube body of the structure which provided the resin tube body 100E of the thin film in the outer peripheral part, and the same resin tube body 100F inside may be sufficient.

In addition, a stenosis is formed in both blood vessels of the vascular bifurcation, and each lesion of the vascular bifurcation lesion is an assembly with a balloon catheter or the like in the procedure of the vascular bifurcation lesion for expanding the stenosis. The balloon part of the balloon catheter is expanded in front of the part and brought into contact with the blood vessel wall to support the reaction force of the guide wire 1 to be advanced, thereby exerting a propulsive force forward of the guide wire 1. A pair of catheters and balloon catheters (not shown) can be inserted into the guiding catheter 110 to facilitate the kissing procedure. The kissing technique referred to here is a guide wire and a balloon catheter that are inserted into two sets of guiding catheters 110 as a set to simultaneously expand the balloon portions of the two balloon catheters in the bifurcation lesion of the blood vessel, This refers to a technique that simultaneously expands the blood vessel inner diameter of two branching stenotic lesions.
As an assembly in such a case, the guide wire 1 is inserted into a balloon catheter having an outer diameter of 0.228 mm to 0.457 mm and an inner diameter of 0.28 mm to 0.90 mm. The assembly is characterized by facilitating a kissing procedure by inserting two pairs of the guide wire and the balloon catheter into a guiding catheter of 1.91 mm to 2.67 mm.

And then, because the tensile strength characteristics when the solution-treated austenitic stainless steel wire is drawn and subjected to low-temperature heat treatment have the characteristics shown in FIG. Supplementary explanation.

As shown in FIG. 3, when the low-temperature heat treatment temperature is 180 ° C. to 525 ° C., the effect of improving the tensile breaking strength of the metal strand can be obtained. Therefore, the coil body 3 composed of the core wire 2 and the radiation transmitting material coil 32 is partially Temperature range (180 ° C. to 525 ° C.) that coincides with the temperature range in which the tensile breaking strength of the metal element wire steeply increases on the joining members 41, 42, 43 to be joined together or the joining member 4 forming the leading plug 5. The tensile fracture strength of the metal wire of the core wire can also be improved by using a eutectic alloy having a melting temperature of.
Specifically, the joining members 41 and 42 have a substantially cylindrical shape with the predetermined dimension, and the rear end joining member 43 is a joint between the radiation transmissive coil member 32 and the core wire 2 with the predetermined dimension. Is a cylindrical shape or a substantially conical shape with a tapered side. (FIG. 1) In addition, joining partially using the joining member 4 here means the joining form of the core wire 2 and the radiation transmitting material coil 32 of each joining member 41-43 and the leading plug 5 in the said Example. The core wire and the coil body 3 are joined together.

The radiation transmitting material coil 32 and the joining member 4 directly joined to the metal strand of the core wire 2 have a temperature range (180 ° C.) in which the melting temperature matches the temperature range in which the tensile breaking strength of the metal strand increases steeply. To 525 ° C.), and by using a eutectic alloy that melts in this temperature range, it is possible to perform strong bonding while improving the tensile breaking strength of the metal wire at the joint.
The joining member 4 is made of a eutectic alloy having a melting temperature of 180 ° C. to 495 ° C., or an eutectic alloy having a melting point of 180 ° C. to 525 ° C. when the metal strand is an austenitic stainless steel wire containing Mo. The eutectic alloy here refers to a special alloy having the lowest melting point (melting temperature) obtained by changing the component ratio of the alloy, and specifically, an alloy material containing gold or silver. 80% by weight of gold as a tin-based alloy material, the balance being tin and a melting temperature of 280 ° C., and 3.5% by weight of silver as a tin-based alloy, the balance being tin and a melting temperature of 221 ° C., and 88% by weight of gold, The balance is germanium, a melting temperature of 356 ° C., a eutectic alloy composed of silver, tin, and indium and having a melting temperature of 450 ° C. to 472 ° C. Table 4 shows typical examples.

The reason why gold is used as the bonding member 4 is to improve visibility under radioscopy, corrosion resistance, and spreadability. The reason why silver is used is to adjust the melting point and the reason why tin is used. In order to improve the wettability with the coil body 3 and the core wire 2 by lowering the melting point, the reason for using indium and copper is to improve the wettability, and the reason for using germanium is an intermetallic compound This is to suppress the coarsening of the crystal grains and prevent a decrease in the bonding strength.

The reason why the melting temperature of the joining member 4 is 180 ° C. to 495 ° C., or 180 ° C. to 525 ° C. is that the tensile breaking strength of the metal strand of the core wire 2 that is hard-drawn and work hardened below 180 ° C. The effect of improving the heat of melting of the joining member 4 is low, and if it exceeds 495 ° C., the characteristics of the austenitic stainless steel wire of the metal strand, or if it exceeds 525 ° C., austenitic stainless steel containing Mo From the characteristics of the wire, when each austenitic stainless steel wire is heated to 520 ° C. or 800 ° C. exceeding 540 ° C., a sensitization phenomenon occurs, and as described above, the tensile fracture strength characteristics are extremely reduced. This is to prevent this phenomenon and to maximize the mechanical strength characteristics of the core wire 2.
And the tensile breaking strength of the said metal strand of each joining part increases with the fusion heat of the joining member 4, and tensile stress increases with this tensile breaking strength increase, As a result, the bending resistance of the core wire 2 in a joining part is repeated. Fatigue properties are improved.

For example, as shown in FIG. 5, each interval between the intermediate joint member 411 and the intermediate joint members 412 and 413 located 50 mm (D dimension in the figure) from the tip of the leading plug 5 is 10 mm (C dimension in the figure). By arranging 10 intermediate joining members and setting the total length between the intermediate joining members to 90 mm, a low-temperature heat treatment is performed over a long position (90 mm in the drawing) of the core wire 2 even when a joining member that is partially joined is used. The tensile breaking strength of the core wire 2 can be increased.
According to this method, it is possible to improve the tensile breaking strength of the core wire 2 at a necessary site even without using a heat treatment furnace by atmospheric heating for heating the whole, even in a partially narrow range. Furthermore, in this structure, by arranging the intermediate joint members 411, 412, and 413 at equal intervals, it is possible to have an effect that the length of the stenotic lesion can be measured. The reason why the position and the range of the intermediate joint member are the above dimensions is that this range corresponds to a stenotic lesion position generally observed in the coronary artery.
And if it supplements, by using the joining member 4 which is a eutectic alloy for the leading plug 5, the tensile breaking strength of the metal strand at the junction between the leading plug 5 and the core wire 2 can be improved, and as a result. Bending fatigue resistance at the joint can be improved within a stenotic lesion. In addition, if it supplements, this joining process will attach the coil body 3 to the outer peripheral part of the core wire front-end | tip part 21, after the grinding process of the mechanical processing of the core-wire front-end | tip part 21, or after a grinding process, and will be joined after that. 4, the joining members 41 to 43, 411, 412, 413 and the leading plug 5 are joined. Thereafter, the resin film 6 is applied to the outer peripheral portion of the coil body 3.

Since the guide wire is immersed in a physiological saline before the procedure or washed with a physiological saline after the procedure, for example, when the joining member 4 uses a silver-based eutectic alloy, the immersion is performed within about one hour. The formation of silver sulfide or the like, or the formation of silver chloride and the photosensitivity of the silver compound starts blackening, and the blackening further proceeds with the passage of time, increasing corrosion and reducing the bonding strength. For this reason, it is desirable to use a bonding member 4 made of a gold-based eutectic alloy in order to prevent a decrease in bonding strength due to the progress of corrosion and to prevent blackening.
When the radiation transmitting material coil 32 and the radiation opaque material coil 31 are partially bonded using the gold-based eutectic alloy bonding member 4, the metal wire of the radiation opaque material coil 31 is gold or gold. If it is the material containing a component and the material which carried out gold plating, the wettability with the said joining member 4 will improve, and it is a more desirable joining form.

Next, a specific example of a medical guide wire using the joining member 4 will be described below.
A medical wire in which a core wire made of a flexible elongated body and a coil spring body having the core wire inserted through the tip of the core wire are attached, and the core wire and the coil spring body are partially joined using a joining member. In the guide wire,
The core wire is made of a metal wire,
The metal element wire is a solution-treated austenitic stainless steel wire, and the final wire drawing is performed after repeating at least one set of drawing and low-temperature heat treatment after drawing as one set,
The total area reduction until the final wire drawing is 90% to 99.5%,
When the low temperature heat treatment is 180 ° C. to 495 ° C., or when the metal strand is an austenitic stainless steel wire containing Mo, the temperature is 180 ° C. to 525 ° C.,
The total increase rate of the tensile breaking strength of the metal strand by the low-temperature heat treatment until the final wire drawing is 8% or more,
After the final wire drawing, the core wire and the coil spring body are partially joined using the joining member as a low-temperature heat treatment using the heat of fusion of the joining member,
The joining member is made of a eutectic alloy having a melting temperature of 180 ° C. to 495 ° C., or when the core wire is an austenitic stainless steel wire containing Mo, from a eutectic alloy having a melting temperature of 180 ° C. to 525 ° C. Consisting of
When the tensile strength at break of the metal wire is Y (kgf / mm @ 2) and the total area reduction is X (%),
Satisfies the relational expression of 450 ≧ Y ≧ 2.000X + 70,
A medical guide wire comprising the core wire using the metal strand.

In addition, as a method for manufacturing a medical guide wire using the joining member 4 together,
A medical wire in which a core wire made of a flexible elongated body and a coil spring body having the core wire inserted through the tip of the core wire are attached, and the core wire and the coil spring body are partially joined using a joining member. In the guide wire manufacturing method,
The core wire is made of a metal wire,
The metal element wire is a solution-treated austenitic stainless steel wire, and after the wire drawing step and the low-temperature heat treatment after the wire drawing step are repeated as at least one set, a final wire drawing step is provided.
The total area reduction until the final wire drawing step is 90% to 99.5%,
When the low-temperature heat treatment step is 180 to 495 ° C. for 10 to 180 minutes, or when the metal strand is an austenitic stainless steel wire containing Mo, the temperature is 180 to 525 ° C. for 10 to 180 minutes,
The total increase rate of the tensile breaking strength of the metal strand by the low-temperature heat treatment step until the final wire drawing step is 8% or more,
Then, when the temperature of the metal strand is 180 ° C. to 495 ° C. for 30 seconds to 180 minutes, or when the metal strand is an austenitic stainless steel wire containing Mo, Under a low-temperature heat treatment process at 180 to 525 ° C. for 30 seconds to 180 minutes,
With one end of the metal wire being subjected to a load load of 5% to 30% of the tensile breaking force of the metal wire before twisting, the other end is twisted from 100 times / m to 275 times / m. The twisting process step under the low-temperature heat treatment to be a processing step,
Thereafter, the step of partially bonding the core wire and the coil spring body using the bonding member is a low-temperature heat treatment step using the heat of fusion of the bonding member,
The joining member is made of a eutectic alloy having a melting temperature of 180 ° C. to 495 ° C., or when the core wire is an austenitic stainless steel wire containing Mo, from a eutectic alloy having a melting temperature of 180 ° C. to 525 ° C. Consisting of
When the tensile strength at break of the metal wire is Y (kgf / mm @ 2) and the total area reduction is X (%),
Satisfies the relational expression of 450 ≧ Y ≧ 2.000X + 70,
A medical guide wire manufacturing method comprising the core wire using the metal element wire.
With this configuration, in particular, the residual stress generated locally by the pressing process of the core wire tip 21 is removed, and the residual stress generated locally by the coil forming process of the coil spring body is removed. It is the medical guide wire which can improve the bending bending fatigue-proof characteristic accompanying the tensile fracture strength improvement of the core wire front-end | tip part 21, and its manufacturing method.

(Effect of the invention)
As described above, the medical guide wire according to the present invention is a combination of the temperature of the metal wire that has been subjected to strong wire drawing and the tensile strength at break by combining strong wire drawing and low-temperature heat treatment. By paying attention to the above, by performing a low-temperature heat treatment suitable for the steel type in a temperature range where the tensile breaking strength increases steeply, a metal wire having a high tensile breaking strength can be obtained.
In addition, the core wire after the final wire drawing is suitable for the steel type in the temperature range where the core wire temperature suddenly increases the tensile breaking strength of the core wire, or “twist processing under low temperature heat treatment” or “twist processing” After bending at the time of introduction into a stenotic lesion with a medical guide wire using a core wire with high tensile strength at break and high linearity and rotation transmission. It is intended to provide a medical guide wire or the like having a new technical idea that improves the restoring force to straight shape and improves the resistance to repeated bending fatigue. There are the above various effects.

1 Guide wire (medical guide wire)
2 Core wire 21 Core wire tip 3 Coil spring body (coil body)
31 Radiopaque material coil 32 Radiation transparent material coil 33 Inner coil spring body 4 Joining member 41 Middle front side joined portion 42 Middle rear side joined portion 43 Rear end joined portion 5 Lead plug 6 Resin coating 7 Hydrophilic coating 100 Microcatheter
110 Guiding catheter

Claims (4)

A medical wire in which a core wire made of a flexible elongated body and a coil spring body having the core wire inserted through the tip of the core wire are attached, and the core wire and the coil spring body are partially joined using a joining member. In the guide wire manufacturing method,
The core wire is made of a metal wire,
The metal strands, with re-melting material of the solid solution treated austenitic stainless steel wire, and a low-temperature heat treatment step after the drawing process and drawing process after repeating at least more than one set as one set, the final Provide a wire drawing process and a low-temperature heat treatment process after the final wire drawing process ,
The total area reduction until the final wire drawing step is 90% to 99.5%,
The low temperature heat treatment step after the wire drawing step and the low temperature heat treatment step after the final wire drawing step are performed at 300 ° C. to 495 ° C. for 10 minutes to 180 minutes, or the metal strand contains austenitic stainless steel wire containing Mo In the case of 300 to 525 ° C. for 10 to 180 minutes,
The total increase rate of the tensile breaking strength of the metal strand by the low-temperature heat treatment step after the wire drawing step until the final wire drawing step is 8% or more,
After the low-temperature heat treatment step after the final wire drawing step , the metal strand is subjected to a load load of 5% to 30% of the tensile breaking force of the metal strand before twisting at one end of the metal strand. In the added state, the other end is a twisting process of 100 times / m to 275 times / m,
Thereafter, the temperature of the metal strand is 300 ° C. to 495 ° C. for 30 seconds to 180 minutes, or when the metal strand is an austenitic stainless steel wire containing Mo, 300 ° C. to 525 ° C. for 30 seconds to 180 minutes. A low-temperature heat treatment step, the low-temperature heat treatment step after the twisting step,
When the tensile strength at break of the metal wire is Y (kgf / mm @ 2) and the total area reduction is X (%),
450 ≧ Y ≧ 2. 15 satisfy the relation of 0X + 70,
A medical guide wire manufacturing method comprising the core wire using the metal element wire. In the manufacturing method of the medical guide wire of Claim 1 ,
In a state where the front Symbol twisting processing step, was added 30% of the load weight from 5% of the tensile breaking force of the metal wire before twisting process to one end of the metal wire, the other end 100 turns / m To 200 times / m twisting process,
A medical guide wire manufacturing method comprising the core wire using the metal element wire. In the manufacturing method of the medical guide wire of Claim 1 or 2 ,
Before Symbol twisting processing step,
Twist the other end with load applied to one end of the metal strand,
The ratio of the load weight W (kgw) to the tensile breaking force P (kgf) before twisting of the metal wire is defined as a load weight ratio X (%), and the load weight ratio X (%) is W ÷ P × 100. In the case of the relationship, the number of twists N (times / m) is
-0.8X + 124 ≦ N ≦ −1.8X + 284 is satisfied,
A medical guide wire manufacturing method comprising the core wire using the metal element wire. In the manufacturing method of the medical guide wire of Claim 3 ,
The twisting process is to twist the other end with a load applied to one end of the metal wire,
The ratio of the load weight W (kgw) to the tensile breaking force P (kgf) before twisting of the metal element wire is defined as a load weight ratio X (%), and the load weight ratio X (%) is W ÷ P × 100. In the case of the relationship, the number of twists N (times / m) is
−0.8X + 124 ≦ N ≦ −2.8X + 264 is satisfied,
A medical guide wire manufacturing method comprising the core wire using the metal element wire.