JPH06319805A - Treatment of core wire of guide wire - Google Patents

Abstract

PURPOSE:To provide a simple, easy and inexpensive process for forming a plating layer with which an contrast effect by X-rays is recognized by plating the specific position at the front end of a core wire to a layer thickness of a specific value with an anode existing symmetrically with the core wire at a specific voltage by using plating liquid contg. a noble metal. CONSTITUTION:The front end of the core wire 1 of a guide wire consisting of a metallic wire as its main elastic material is immersed at 1 to 5mm into the plating liquid 3 contg. the noble metal and is energized with substantially the specific voltage, by which the plating layer having >=20mum thickness is formed. The core wire is plated with the same voltage for >=80% of the metal quantity of the plating layer and the electrodes to be used for the plating are arranged symmetrical with the core wire 1 as a center. Further, the metallic wire is formed of a stainless steel, superrelastic type titanium-nickel alloy, process hardening titanium-nickel alloy and the noble metal is formed of gold, platinum, iridium, rhenium and their alloys. As a result, the processes are made easier and simpler and the manpower for these processes is saved. There is substantially no need for manual labor after the guide wire is mounted in a core wire holder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a core wire for externally confirming the insertion position of a guide wire, which is mainly used by inserting it into a blood vessel in the body for medical purposes, from the outside. .

[0002]

2. Description of the Related Art With respect to guide wires and catheters used for similar purposes, many patents and utility models have been published as means for external confirmation by X-ray. These are roughly classified into the following four types. 1.
A core wire is made of a radiopaque material. 2. Add contrast material to the coating. 3. Encapsulating radiopaque spheres, sleeves, coils, tubes, and other moldings at the tip of the coating. 4. Whether to insert or crimp a radiopaque molded product at the tip of the core wire,
Or braze. And so on. The present invention relates to these prior art 4. It is positioned as an improvement of.
Regarding the method of attaching the X-ray opaque material to the core wire, brazing or soldering (Japanese Patent Application No. 50-149675, 58-
97750, 59-237406, 62-3281
9) As a base, molded products such as sleeves, coils, and tubes are prepared in advance and attached by soldering after plating or pressure fixing (Japanese Patent Application No. 63-334359).

[0003]

The above-mentioned conventional techniques have the following drawbacks. 1. There are many steps, and precision and skill are required. The material to be attached must be processed beforehand, but the tip of the core wire is 0.1 mm to 0.0
At 5 mm, it is necessary to attach a radiopaque material, especially in such cases. The molded product attached to this core wire is
Regardless of the method of brazing, soldering, or crimping and fixing, it is extremely fine, and any of the die processing, press processing, and rolling processing of precious metal materials requires precise and time-consuming processing. The same applies to brazing and soldering, and in some cases it is a precise and technical work performed under a magnifying glass. 2. Product variability and high cost Since the work process is complicated and precise, and inefficient manual work such as brazing is included, the product variability is inevitably large and the cost is high. 3. Negative effect on core material Both stainless steel and titanium-nickel alloy retain their characteristics by heat treatment during manufacturing.
In No. 4, the solution temperature is 1010 ° C, and the shape memory treatment temperature of the titanium-nickel alloy is 300 ° C to 500 ° C.
When the temperature exceeds this temperature, the properties change remarkably, but the melting point of silver wax is 620 ° to 900 ° C, and there is a sufficient possibility of exceeding this temperature by gas flame heating which is a general brazing method. In this case, the most important characteristic of the guide wire is the resilience to bending and the tenacity to repeated bending, which leads to breakage of the tip of the core wire and drop of the molded product. 4. Stress concentration due to the step between the molded product and the wire rod A step is created between the end of the molded product and the wire rod, and stress concentration occurs due to the bending stress applied during the use of the guide wire.
It may cause breakage and drop of molded products. If the molded product falls off during use of the guide wire, the thin tip of the core wire directly hits the coating of the guide wire, and there is a risk of breaking the coating and piercing the blood vessel. 5. Complexity of plating by controlling the current In conventional plating, the plating layer was homogenized by keeping the current per unit surface area of the object to be plated constant, but in plating the core wire, the surface area increases with the progress of plating. However, program control is required for this purpose.

According to the present invention, the tip of the core wire is vertically dipped in a plating solution containing a noble metal and a current is applied at a substantially constant voltage to form a plating layer of 20 μm or more in which an X-ray contrast effect is recognized, The purpose is to make the process simple, simple, and low cost, to make products uniform, to prevent defective products, and to prevent accidents due to products.

[0005]

In order to achieve the above object, the present invention does not use molded articles such as balls, sleeves, coils, tubes, etc., and plating 1 to 5 mm of the tip of the core wire to a thickness of 20 μm or more. .

The tip portion of the core wire of 1 to 5 mm is vertically dipped into a plating solution containing a noble metal for a predetermined length and connected to the negative side of a constant voltage power source. The longer the plating length is, the greater the contrast effect is, but if it is 5 mm or more, the flexibility of the distal end portion of the guide wire may be impaired. If it is 1 mm or less, the contrast property is insufficient.

The anodes are arranged symmetrically with respect to the core wire in order to avoid uneven thickness of the plating layer.

The metal to be plated may be any material that is opaque to X-rays, but gold, platinum, iridium and rhenium have a great effect and are suitable for plating.

For the plating, a constant voltage power source may be used to supply a constant voltage all the time. However, it is sufficient to control the voltage at 10% in each case even in consideration of improvement of deposition at the start of plating and finish at the end. .

[0010]

In the method of treating the core wire of the guide wire constructed as described above, the following effects can be considered. 1. Maintaining the homogeneity of the plating layer by plating at a constant voltage In normal plating, the thickness of the plating layer is kept constant by keeping the current per plating area constant, and the plating layer is homogenized. . However, in plating the core wire,
In order to secure the X-ray contrast effect, for example, plating may be performed to the same thickness as the core wire. At this time, the plated area is tripled at the start and end of plating. Therefore, the current must be increased proportionally. on the other hand,
Since the electric resistance between the core wire and the anode is almost inversely proportional to the surface area of the core wire, the current increases in proportion to the surface area when the voltage is constant. This can be expressed as a mathematical formula as follows.

[Equation 1] ... Equation 1 I is current, S is surface area, a is constant

[Equation 2] ・ ・ ・ Equation 2 R is electrical resistance, b is constant

[Equation 3] ・ ・ ・ Equation 3 V is the voltage If equations 1 and 2 are substituted into equation 3,

[Equation 4] ············································································································· If kept constant, the current per surface area is constant even if the surface area increases. In this way, by keeping the voltage constant, the plating layer became homogeneous, and it was possible to perform thick plating without peeling or cracking.

2. Prevention of uneven thickness by arranging the anode in a symmetrical position with respect to the core wire With one anode, the amount of metal deposited by plating tends to decrease in the part on the back side of the core wire when viewed from the anode,
Uneven thickness. Since the uneven thickness causes peeling and cracking, the anodes are placed at symmetrical positions on both sides of the core wire, and plating is performed from the front and back under the same conditions to prevent the uneven thickness from occurring.

3. Eliminating the step due to the surface tension of the plating solution and relaxing the stress concentration of bending stress When the core wire is suspended vertically in the plating solution, the core wire lifts the surrounding solution by the surface tension. FIG. 1A is an explanatory diagram of this. 12 is the plating liquid lifted by the surface tension. This part has a slower plating speed,
As a result, the core wire is plated in the state as shown in FIG. B1, and a gentle gradient 11 is formed between the plated portion 14 below the liquid surface and the non-plated portion 13 above the liquid surface. As a result, with respect to the bending stress 15 at the tip portion, the stress is concentrated in a narrow range when there is a step using the molded product 16 of FIG. 2A, but the bending stress of the core wire processed according to the present invention is as shown in FIG. 2B. Thus, the stress concentration is alleviated by being widely distributed in the gradient portion.

3. Water droplet type of core wire tip shape and protection effect on the coating of the tip portion By suspending the core wire vertically in the plating solution and energizing it, the plating shape of the tip portion becomes a water drop shape, and the tip of the core wire may damage the coating. , Prevent breaking through. The reason for such a shape is that the electric charge is collected at the tip and the current density is increased.

4. Retention of Metallic Physical Properties of Core Wire by Not Heating Since the core wire processing method according to the present invention does not heat like brazing and soldering, the physical properties of the core wire are maintained as they are at the time of manufacture.

5. Clear contrast property for X-rays According to the method for treating the core wire of the guide wire according to the present invention, it is possible to clearly trace the thickness of the plating layer from about 20 μ with the X-ray intensity normally used for the human body.
0.1mm element wire wound tightly wound coil and wall thickness 75μ
A contrast property comparable to that of the tube was obtained. This means that the plated layer is as dense as the molded product.

6. Types of noble metals and contrast properties Many metals have superior contrast properties to core wire materials, but the precious metals listed in claim 5 are particularly excellent in contrast properties and are relatively easy to obtain as plating materials, and adhere to core wires. It has good properties and is free from peeling even if it is thickly plated according to the present invention.

[0017]

【Example】

Example 1. An embodiment will be described with reference to the drawings,
FIG. 3 is a perspective sectional view of the plating apparatus of the embodiment of the core wire treatment according to the present invention. A plating solution 3 containing 8 g / l of platinum was placed in the plating tank 2, and 15 cm of the tip of a work hardening type titanium-nickel alloy wire having a diameter of 0.8 mm was tapered and corroded to a diameter of 0.1 mm at the tip. Core wire 1
Was fixed to the core wire holder 10 so that the tip 2 mm was vertically immersed in the plating solution 3. Numerals 4 and 4 ′ are anodes in which platinum is plated on the titanium surface, and are arranged at positions symmetrical with respect to the core wire. That is, A, A ′, B and B ′ are virtual lines drawn for the purpose of explanation, and A and A ′ are parallel to the plating liquid surface 7 from the tip 5 of the core wire 1 to the anodes 4 and 4 ′. B and B ′ are lines drawn so as to connect the tip 5 of the core wire to the deepest portions 6, 6 ′ of the anode. A and B and A '
And B ', and the included angles α and α'of A, B, A', B'are equal to each other. To the minus of the constant voltage power supply, the core wire holder 10
The cable 9 attached to the above was connected, and the cables 8 and 8'attached to the anode were connected to the plus, and electricity was applied for 9 hours at a voltage of 1.2V. The tip of the core wire 1 is platinum-plated so that the average diameter of the thickest part is 0.29 mm, and the uneven thickness is 0.03.
It was less than mm. Plating layer shear adhesion strength is 63kg
Every square centimeter or more. When this core wire was covered with urethane rubber to produce a guide wire, the X-ray contrast and flexibility were excellent.

Example 2. In the embodiment shown in FIG. 4, the core wire 1 is annularly arranged in a round plating tank, a round rod-shaped anode 4 ′ is arranged at the center, and the annular anode 4 is arranged symmetrically with respect to the core wire. FIG. 3 is a perspective sectional view of the plated device. Put the plating solution 3 in the plating tank 2 and wire diameter 0.1mm, winding diameter 2
A tightly coiled stainless steel core wire having a diameter of 5 mm was fixed to the core wire holder 10 such that the tip 5 mm was immersed in a plating solution containing 11 g / l of gold. 4, 4 ', A, A', B, B ', α,
The relationship between α ', 6, 6'is the same as in the first embodiment. The negative of the constant voltage power source was connected to the cable 9 and the positive was connected to 8, 8 ', and electricity was supplied for 8 hours at a voltage of 1.05V. The increase in coil diameter was 0.2 mm. When a guide wire was manufactured by coating the core wire with nylon, both X-ray contrast and flexibility were excellent.

Example 3. Using the plating apparatus shown in FIG. 3, a tapered superelastic titanium-nickel alloy core wire having a diameter of 0.5 mm and a tip diameter of 0.08 mm was subjected to iridium-rhenium alloy plating on the tip of 2 mm. A voltage of 1.25 V was applied for 11 hours to obtain a plated layer having a layer thickness of 90 μm. The adhesion strength of the plating layer was not less than the breaking strength of the core wire and was about 350 g. As a result of manufacturing a guide wire by coating the core wire with urethane rubber, the X-ray contrast and flexibility were excellent.

[0020]

Since the present invention is constructed as described above, it has the following effects.

1. The process is easy and simple, labor is saved, and little labor is required after mounting on the core wire holder.

2. There are no processes that require skill such as precision processing and brazing, the number of processes itself is small, and the product is automatically plated by energizing, so there is less variation in products, fewer defective products and less rework. . In Example 1, the cost was reduced by about 60%.

3. Since the proportion of manual work in the whole process is reduced, mass production effect can be expected. That is, the cost can be reduced by mass production.

4. There is no adverse effect on the core wire material due to heating, and there is almost no occurrence of in-process defects due to bending or bending of the tip of the core wire.

5. The adhesion strength of the plating was practically sufficient, and no precious metal part came off.

6. Since the step between the noble metal part and the core wire is gentle, the tip of the tip part is not broken due to bending stress.

7. Due to the above-mentioned multiple effects, the noble metal at the tip part is prevented from falling off, and the tip of the noble metal is rounded due to the characteristics of plating, so that the core wire does not break through the tip part coating during use. I was able to avoid the danger.

Since a commercially available constant voltage power source can be used, the equipment cost is lower than that of the current control, and unsupervised operation is possible.

[0029]

[Brief description of drawings]

FIG. 1 is an explanatory diagram in which an A core wire lifts a plating liquid surface by surface tension. It is explanatory drawing of the plating state of B core wire.

FIG. 2 is an explanatory diagram of distribution of bending stress when there is a step using a molded product at the tip of the A core wire. B is an explanatory diagram of distribution of bending stress when a core wire is processed according to the present invention.

FIG. 3 is a perspective sectional view of a plating apparatus according to an embodiment of core wire treatment.

FIG. 4 is a perspective cross-sectional view of a plating apparatus according to an embodiment of core wire treatment.

[Explanation of symbols]

 1 core wire 2 plating bath 3 plating solution 4, 4'anode 5 tip of core wire 6, 6'deepest part of anode 7 plating liquid level 8, 8'cable attached to anode 9 cable attached to cathode 10 core wire holder 11 loose Gradient 12 Plated liquid lifted by surface tension 13 Non-plated part on liquid surface of core wire 14 Plated part under liquid surface of core wire 16 Molded product

Claims (5)

[Claims] 1. A guide wire whose main elastic material is a metal wire, in which 1 to 5 mm of a tip end of a core wire is vertically immersed in a plating solution containing a noble metal, and a current is applied at a substantially constant voltage to obtain a thickness of 20.
A method of treating a core wire of a guide wire, characterized by forming a plating layer of μ or more 2. The method for treating a core wire according to claim 1, wherein 80% or more of the metal amount of the plating layer is plated at the same voltage. 3. The method for treating a core wire according to claim 1, wherein the anodes used for plating are arranged symmetrically with respect to the core wire. 4. The method for treating a core wire according to claim 3, wherein the metal wire according to claim 1 is stainless steel, a super elastic titanium-nickel alloy, or a work hardening titanium-nickel alloy. 5. The method for treating a core wire according to claim 4, wherein the noble metal according to claim 1 is gold, platinum, iridium, rhenium or an alloy thereof.