JP2015100664A - Fluorine coated wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorine coated wire which is used for a medical guide wire for guiding a catheter or the like, is manufactured by coating a thin metallic wire with a fluorine resin, and satisfies excellent sliding property, perceptibility and coil work resistance, and a method of manufacturing the fluorine coated wire.SOLUTION: A fluorine coated wire 1 has a metallic fine wire 2, a lower layer 3 coating the metallic fine wire 2, and a surface layer 4 coating the lower layer 3. The lower layer is constituted of a mixture which is obtained by dispersing 5 mass% or more of a pigment in a resin containing an engineering resin excellent in adhesion to a fluorine resin and a core wire as a main component. The surface layer is constituted of a resin containing polytetrafluoroethylene as a main component. There is also provided a method of manufacturing the fluorine coated wire 1. In the fluorine coated wire 1, the engineering resin is polyamide imide or polyether sulfone.

Description

  The present invention relates to a fluorine-coated wire that is used as a guide wire or the like for guiding a catheter to be inserted into a blood vessel, a trachea or the like, and is formed by coating a metal fine wire (core wire) with a fluororesin.

  When a catheter is inserted into a blood vessel, trachea, etc. for inspection or treatment, a wire (guide wire) made of a fine metal wire is first inserted to the target site in the tube, and the catheter is guided by the wire. The method of leading to the site is performed. In some cases, a wire such as that described above is inserted into a blood vessel, trachea, etc., and inspection or treatment is performed using the wire.

  Such a wire is desired to have low frictional resistance with the inner wall of the catheter or the like. Thus, for example, Patent Document 1 discloses a guide wire in which a fluororesin is coated on a wire serving as a core wire and frictional resistance with a catheter or the like is reduced. Patent Document 2 discloses a medical guide wire and a method for manufacturing the same, in which protrusions are formed on the outermost layer of the guide wire to reduce the frictional resistance between the catheter inner wall and the guide wire, and the contact area with the catheter inner wall is reduced. It is disclosed. And according to this medical guide wire, it is described that the frictional resistance with the catheter inner wall is reduced to half or less. Furthermore, Patent Document 3 discloses a guide wire in which a depression is formed in the outermost layer of the guide wire to reduce the contact area with the inner wall of the catheter and reduce the frictional resistance. The guide wire with protrusions described in Patent Document 2 is removed by sterilization treatment by electron beam or gamma ray irradiation, and the effect of reducing frictional resistance is lost. According to the guide wire of Patent Document 3, It is described that the effect of reducing frictional resistance is not lost even by sterilization.

  Such wires are also required to have moderate flexibility in order to facilitate entry. Therefore, in order to adjust the flexibility, adjustment of the wire diameter for covering the metal wire with urethane is generally performed. However, when this wire is coated with fluorine to reduce the frictional resistance with the inner wall of the catheter, the melting point of urethane is as low as 160 ° C., so that there is a problem that the urethane is deformed by the heat at the time of firing the fluororesin. Patent Document 4 describes a method of solving this problem by forming an intermediate layer made of a material having excellent heat resistance as a thermal buffer layer.

  Furthermore, Patent Document 5 discloses a medical device such as a guide wire that can secure the flexibility of the distal end portion and easily and reliably grasp the position of the portion in the living body. A first layer composed of a long linear body having flexibility, and at least a coating layer on the outer periphery on the front end side is composed of a material including a low-friction resin material such as fluororesin and a binder resin material; A second material formed on the first layer, comprising the low-friction resin material and a pigment, wherein the content of the binder resin material is less than or less than that of the first layer. There is disclosed a medical device comprising a layer and a third layer formed on the second layer and made of a material containing the low friction resin material.

  As a core wire of such a medical wire, a wire obtained by processing a metal thin wire such as stainless steel (SUS) into a coil shape is widely used in order to facilitate entry into a blood vessel, a trachea and the like. As a method of coating such a wire, for example, a coiled SUS wire, with a fluorine resin, a method of coating a fluorine paint by spray coating has been generally performed. However, in this method, since the paint loss is large and the uniformity of the film thickness is also inferior, it is desirable that the wire be coated with fluorine before being coiled and then coiled after the fluorine coating.

Japanese Patent Laid-Open No. 3-41966 Japanese Patent No. 3876243 JP 2010-234808 A JP 2006-68497 A WO2010 / 018762

  As described above, medical wires such as guide wires are required to have flexibility and low frictional resistance with the inner wall of the catheter (hereinafter referred to as “slidability”). Moreover, it is also required to have excellent visibility when used for treatment or the like. Therefore, when the wire is subjected to fluorine coating, the fluorine coating needs to be colored green or the like. Furthermore, the flexibility of the wire can be obtained by coiling the wire. However, if this coil processing is performed after fluorine coating, the fluorine coating will not be scraped or peeled off during coil processing (excellent coil workability) : That is, ease of manufacture by coil processing) is required.

  However, with conventional fluorine-coated wires, it has been difficult to satisfy excellent slipperiness, visibility and resistance to coil processing at the same time. That is, in order to obtain excellent visibility, it is necessary to add a large amount of pigment (particularly green pigment) to the fluororesin (usually 5% by mass or more), but in this case, the fluorine coat layer becomes brittle. Coil resistance is reduced, and fluorine coating is likely to be scraped or peeled off during coil processing. On the other hand, in order to satisfy both excellent visibility and coil workability at the same time, a method of blending a material with excellent toughness, strength, and adhesion into the fluorine coat layer can be considered, but in this case, slipperiness decreases, The frictional resistance with the inner wall of the catheter cannot be made sufficiently low.

  The present invention is a fluorine-coated wire that is used as a guide wire for guiding a catheter and is formed by coating a thin metal wire with a fluorine resin, and simultaneously satisfies excellent slipperiness, visibility, and resistance to coiling. An object of the present invention is to provide a fluorine-coated wire.

The first embodiment of the present invention comprises:
A metal thin wire, a lower layer covering the metal thin wire, and a surface layer covering the lower layer,
The lower layer is constituted by a mixture in which a pigment containing 5% by mass or more of the resin is dispersed in a resin containing, as a main component, an engineering plastic excellent in adhesiveness with a fluororesin and the fine metal wire,
The surface layer is a fluorine-coated wire made of a resin whose main component is polytetrafluoroethylene (PTFE).

The second embodiment of the present invention is:
The metal fine wire was immersed in a dispersion containing a fluorine resin and an engineering plastic excellent in adhesion to the metal fine wire as a main component and a dispersion in which 5% by mass or more of the pigment was dispersed or dissolved in a dispersion medium with respect to the resin. A lower layer forming step of performing post-drying to form a lower layer;
A surface layer forming step of forming a surface layer covering the lower layer by immersing the metal fine wire formed with the lower layer in a dispersion in which resin particles containing PTFE as a main component are dispersed in a dispersion medium, and then drying;
Fluorine coat having a step of firing after surface layer formation and fusing the resin particles containing the lower layer fluororesin and PTFE of the surface layer as main components, and a coiling step of processing the fired metal wire into a coil shape It is a manufacturing method of a wire.

  According to the first embodiment of the present invention, there is provided a fluorine-coated wire that can simultaneously satisfy excellent slipperiness, visibility, and resistance to coil work. Moreover, according to the second embodiment, a fluorine-coated wire having excellent slipperiness and visibility can be manufactured so that the fluorine coat is not scraped or peeled off during coil processing.

It is sectional drawing which shows typically the structure of the fluorine coat wire of one embodiment of this invention.

  As a result of intensive studies on the configuration of the fluorine coat of the medical fluorine coat wire, the present inventors have made the fluorine coat into a two-layer structure of a lower layer and a surface layer (outermost layer), and the lower layer has excellent adhesion to the core wire. When a predetermined amount of pigment is dispersed in a resin mainly composed of engineering plastic and fluororesin, and the surface layer is composed of a resin mainly composed of PTFE, excellent slipperiness, visibility and coil resistance The present inventors have found that a fluorine-coated wire that can simultaneously satisfy the properties can be obtained.

[First Embodiment]
The first embodiment of the present invention comprises:
A metal thin wire, a lower layer covering the metal thin wire, and a surface layer covering the lower layer,
The lower layer is constituted by a mixture in which a pigment containing 5% by mass or more of the resin is dispersed in a resin containing, as a main component, an engineering plastic excellent in adhesiveness with a fluororesin and the fine metal wire,
The surface layer is a fluorine-coated wire made of a resin whose main component is PTFE.

  Here, “main component” means that the material is contained in an amount of 50% by mass or more, preferably 80% by mass or more, but may contain other materials within a range not impairing the gist of the invention. In addition, the case of only the material is included in the meaning of “main component”.

  FIG. 1 is a cross-sectional view schematically showing the configuration of the fluorine-coated wire of the first embodiment. The fluorine-coated wire 1 includes a core wire (fine metal wire) 2, a lower layer 3 formed on the core wire 2 and covering the core wire 2, and a surface layer 4 formed on the lower layer 3 and covering the lower layer 3.

  The core wire 2 is a metal thin wire, and a stainless steel (SUS) wire or a piano wire having a diameter of about 0.02 to 1.00 mmφ, preferably 0.10 to 0.80 mmφ is used.

(About the lower layer)
The lower layer is a coating layer formed in close contact with the core wire. In the known technique, when the coating layer in close contact with the core wire contains a large amount of pigment, the coil process resistance is reduced, and the coating layer is easily peeled off or peeled off during coil processing. Because it is composed of a resin that contains engineering plastics that have excellent adhesion to fluororesin and fine metal wires (core wires) as its main component, even if it contains 5% by mass or more of pigment, it has excellent resistance to coiling and is prevented from being scraped or peeled off. A workable wire is obtained. Moreover, since the lower layer contains 5 mass% or more of pigments, sufficient visibility can be obtained.

(Ratio of fluororesin to engineering plastic)
The ratio of the fluororesin and the engineering plastic constituting the lower layer is preferably 1: 9 to 9: 1 by mass ratio, more preferably 3: 7 to 7: 3. That is, when the ratio of the fluororesin and the engineering plastic is within this range, it is preferable because strong adhesion between the fine metal wire and the surface layer can be achieved.

  Therefore, as a preferred aspect, there is provided the fluorine-coated wire according to the first embodiment in which the mass ratio of the fluororesin and engineering plastic constituting the lower layer is 1: 9 to 9: 1.

(Engineering plastic types)
As the engineering plastic constituting the lower layer, a resin having excellent strength and high heat resistance and excellent adhesion to the core wire (metal fine wire) is used. Specifically, polyamideimide (PAI), polyethersulfone (PES), polysulfone, polyimide, polyetheretherketone, polyaryleneketone, polyphenylenesulfide, polyarylenesulfide, polyetherimide, polyimidesulfone, polyallylsulfone , Polyallyl ether sulfone, polyester, epoxy resin, polyphenylene sulfide, polyester imide, polyamide, polyarylate, polycarbonate and the like. Among these, PAI and PES are preferably used because they are particularly excellent in compatibility with the fluororesin and adhesiveness with the core wire.

  Therefore, as a preferred aspect, there is provided the fluorine-coated wire according to the first embodiment, wherein the engineering plastic constituting the lower layer is PAI or PES.

(Fluorine resin types)
Examples of the fluororesin constituting the lower layer include PTFE, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), and tetrafluoroethylene-hexafluoropropylene copolymer. Examples include a polymer (FEP), polychlorotrifluoroethylene (PCTFE), and a tetrafluoroethylene-ethylene copolymer (ETFE).

  Among them, PTFE, PFA, which has excellent adhesion to the surface layer and has the same tetrafluoroethylene (TFE) unit as the surface layer material, has a high melting point, and has excellent heat deterioration resistance, excellent in adhesion with the surface layer. A fluororesin selected from the group consisting of FEP and mixtures thereof is preferred. Therefore, as a preferred embodiment, there is provided the fluorine-coated wire according to the first embodiment, in which the fluororesin constituting the lower layer is selected from the group consisting of PTFE, PFA, FEP and a mixture thereof.

(Pigment)
As the pigment, a green inorganic pigment is preferably used, and specifically, a pigment such as chromium oxide or cobalt green is preferably used. The visibility required when using as a guide wire etc. is acquired by making the ratio of a pigment into 5 mass% or more with respect to resin which comprises a lower layer as mentioned above. On the other hand, the ratio of the pigment is preferably 30% by mass or less based on the resin. When it exceeds 30 mass%, coil workability may become inadequate. More preferably, it is 10-20 mass% with respect to resin.

(Lower layer thickness)
Although the range of the thickness of a lower layer is not specifically limited, As a guide wire for catheters, 1-7 micrometers is usually preferable. If the thickness is less than 1 μm, sufficient adhesion between the metal and the surface layer may not be obtained, and if it exceeds 7 μm, the coil workability may be deteriorated.

(About the surface layer)
A surface layer is a layer which coat | covers the said lower layer, and is an outermost layer of a coating layer. Therefore, when used as a guide wire, it is a layer in contact with the inner wall of the catheter. In this embodiment, since the surface layer is made of a resin containing PTFE as a main component, a fluorine-coated wire excellent in slipperiness can be obtained, and the frictional resistance with the catheter inner wall or the like can be sufficiently lowered.

  The surface layer may be PTFE alone or may contain other components as long as it does not impair the spirit of the invention. Examples of other components include fluorine resins other than PTFE and engineering plastics.

  The surface layer preferably does not contain a large amount of pigment. When a pigment is included in the surface layer, a so-called “buzz” due to agglomerates of the pigment may occur on the surface. In this embodiment, by including the pigment only in the lower layer, a fluorine-coated wire having no appearance and excellent appearance can be obtained.

(Types of PTFE constituting the surface layer)
PTFE which is the main component of the resin constituting the surface layer is preferably PTFE having a low crystallinity. By using PTFE having a low crystallinity for the surface layer, the coil workability can be further improved.

  The PTFE having a low crystallinity is obtained by heating and baking PTFE to a melting point (327 ° C.) or higher, preferably 340 ° C. or higher, and then rapidly cooling, preferably 30 ° C./second or more, more preferably 60 ° C./second or more. It is obtained by cooling at a speed. The PTFE thus obtained has a sufficiently low degree of crystallinity, and by using this PTFE for forming the surface layer, it is possible to more reliably form a fluorine coat having excellent coil workability.

  Therefore, as a preferred embodiment, the fluorine-coated wire according to the first embodiment is provided in which the PTFE constituting the surface layer is PTFE having a low crystallinity. Furthermore, after the PTFE having a low crystallinity is heated and baked to 340 ° C. or higher and then cooled, the fluorine-coated wire is cooled at a rate of 30 ° C./second or higher.

(Surface thickness)
The range of the thickness of the surface layer is not particularly limited, but 1 to 7 μm is usually preferable as a guide wire for a catheter. If it is less than 1 μm, the slipperiness may be lowered, and if it exceeds 7 μm, the coil workability may be lowered.

[Second Embodiment]
The second embodiment of the present invention is:
A metal fine wire, a resin containing as a main component an engineering plastic excellent in adhesion to a fluororesin and a metal fine wire (core wire), and a dispersion in which a pigment of 5% by mass or more with respect to the resin is dispersed or dissolved in a dispersion medium A lower layer forming step of forming a lower layer by drying after dipping,
A surface layer forming step of forming a surface layer covering the lower layer by immersing the metal fine wire formed with the lower layer in a dispersion in which resin particles containing PTFE as a main component are dispersed in a dispersion medium, and then drying;
Fluorine coat having a step of firing after surface layer formation and fusing the resin particles containing the lower layer fluororesin and PTFE of the surface layer as main components, and a coiling step of processing the fired metal wire into a coil shape It is a manufacturing method of a wire.

  The fluorine coated wire of the first embodiment can be produced by the method of the second embodiment. Therefore, the fine metal wire (core wire), the fluororesin, the engineering plastic, the pigment and the like used in this manufacturing method are the same as those described in the first embodiment.

  In the method of the second embodiment, after applying a resin or the like constituting the lower layer on the core wire, drying is performed to form a lower layer covering the core wire. After forming the lower layer, a resin constituting the surface layer is applied on the lower layer and dried to form the surface layer, followed by firing and then coiling.

  The method of the second embodiment is characterized in that the resin or the like is applied in the lower layer and surface layer forming steps by using a resin dispersion and immersing and drying the core wire in the resin dispersion. The resin dispersion is obtained by dispersing resin fine particles such as PTFE in a dispersion medium. For example, commercially available products such as 31-JR (Mitsui / Dupont Fluoro Chemical Co., Ltd.) can be used. As the dispersion medium, water and organic solvents such as N-methyl-2-pyrrolidone, methyl isobutyl ketone, and xylene are usually used.

  Dispersions used in the lower layer forming step include engineering plastics, pigments, etc. in addition to fluororesin fine particles. This dispersion is obtained by dispersing and dissolving engineering plastics, pigments, etc. in a fluororesin dispersion. .

  The concentration of the dispersion is appropriately determined according to the coating conditions and the thickness of the lower layer and the surface layer to be formed. The dispersion is adjusted so that the components are sufficiently mixed and the constituent materials are uniformly dispersed.

  Drying is performed to remove the dispersion medium, and firing is performed to fuse resin fine particles such as PTFE. Therefore, the firing temperature is preferably equal to or higher than the melting point of the resin (327 ° C. in the case of PTFE).

  The wire on which the surface layer is formed is coiled using a coiling device such as a pin coiling device. The coiling conditions can be the same as those used in the production of conventional medical fluorine coated wires. The diameter and pitch of the coil are appropriately determined according to the application, but the coil diameter is generally 3.0 mmφ or less, and may be 2.0 mmφ or less in some cases.

  In this embodiment, the coating is formed by immersing the core wire in the mixture and resin dispersion constituting the lower layer and the surface layer, so that the coating can be formed without losing the mixture and the resin. Since the core wire before coiling is coated with fluorine, it can be coated with a more uniform film thickness.

  Firing in the surface layer forming step is performed at a temperature at which PTFE is sintered at 340 ° C. or higher, specifically at 380 to 400 ° C. for 10 to 30 minutes, and then cooled at 30 ° C./second or more, more preferably 60 ° C./second or more. It is preferable to quench at a speed. By performing such rapid cooling, the PTFE constituting the surface layer can have a low crystallinity, and the coil workability can be improved.

1. Preparation of fluorine-coated wire before coiling (1) Used raw material [resin]
PTFE dispersion: average particle size 0.2 μm, dispersion medium; mixed solvent of N-methyl-2-pyrrolidone, methyl isobutyl ketone and xylene
PAI: Torlon AI-10 (manufactured by Solvay Advanced Polymers)
PES: Sumika Excel 4100MP (Sumitomo Chemical Co., Ltd.)
[Pigment] Chromium oxide (green pigment)
[Metallic fine wire (core wire)]
A stainless steel wire made of SUS304 and having a diameter of 0.2 mmφ was used as a core wire (metal thin wire).

(2) Formation of lower layer (Experimental Examples 1-3)
Add and disperse and dissolve the pigment so that it becomes the blending amount described in PTFE, PAI or PES, and the pigment blending amount column so as to be the composition described in the lower layer column of Tables 1 and 2. A dispersion was prepared. The core wire was immersed in this lower layer dispersion, and then heated and dried at 90 ° C. for 10 minutes to form a lower layer having a thickness of 3 μm on the core wire.

  Subsequently, the core wire on which the lower layer was formed was immersed in a PTFE dispersion, heated and dried at 90 ° C. for 10 minutes, heated (fired) at 380 ° C. for 20 minutes, and further cooled according to Tables 1 and 2 It cooled at the speed | rate, the surface layer of thickness 3 micrometers was formed on the said lower layer, and the fluorine coat wire before coiling was produced. When the cooling rate is high, PTFE with a low crystallinity is formed, and when it is low, PTFE with a high crystallinity is considered to be formed. The same applies to Examples 4 to 6). The cooling at 350 ° C./second was specifically performed by a method of immersing in water after completion of firing and cooling in one second. Cooling at a cooling rate of 5 ° C./sec (300 ° C./min) was performed by a programmed operation in a thermostatic bath.

(Experimental example 4)
A fluorine-coated wire before coiling was prepared in the same manner as in Experimental Example 1, except that PAI and PES were not added, and only PTFE and a pigment were added to prepare a lower layer dispersion.

(Experimental example 5)
A fluorine-coated wire before coiling was produced in the same manner as in Experimental Example 4, except that PAI and pigment alone were added without adding PTFE to produce a dispersion for the lower layer.

(Experimental example 6)
Fluorine coating before coiling in the same manner as in Experimental Example 1, except that no pigment was added to the dispersion for the lower layer, and the pigment was added to the PTFE dispersion used for forming the surface layer so that the blending amount shown in Table 2 was obtained. A wire was made.

(Experimental example 7)
The surface layer was not formed, and only the lower layer was formed on the core wire in the same manner as in Experimental Example 1 to prepare a fluorine-coated wire before coiling having one layer of fluorine coating having a thickness of 6 μm.

2. Evaluation The evaluation shown below was performed using the fluorine-coated wire (wire sample) before coiling prepared in the above experimental examples 1-7. The results are shown in Tables 1 and 2.

(1) Evaluation method a. Resistance to coil processing Using a pin coiling device, wire samples were processed into a coil shape, the coil diameter was gradually narrowed, and the coil diameter was measured when the fluororesin coat on the outside of the coil began to scrape or peel off. It was shown in 2. The coil diameter of 3.0 mmφ was used as a reference value for pass / fail judgment, and the case where the measured value was 2 mmφ or less was excellent, the case of 2.0 to 3.0 mm was passed, and the case of exceeding 3.0 mmφ was rejected.

b. Sliding property A wire sample was inserted into a U-shaped polyethylene tube (bending radius = 70 mm) and slid to measure a dynamic friction coefficient (load: 200 g, sliding speed: 100 mm / min). A coefficient of dynamic friction of 0.10 was used as a reference value for acceptance / rejection determination.

c. Colorability The color tone of the wire sample was visually examined, and the case where green color could be confirmed was regarded as acceptable, and the case where it was not confirmed was regarded as unacceptable.
d. Appearance The appearance of the wire sample was examined with an optical microscope, and the case where no “buzz” occurred on the surface was accepted, and the case where it occurred was rejected.

  As shown in Table 1, the fluorine coat is composed of two layers of a lower layer 3 and a surface layer 4, the lower layer 3 is composed of PTFE + PAI, pigment 12%, or PTFE + PES, pigment 12%, and the surface layer 4 is composed of PTFE. 1 to 3 all passed the coil workability, slipperiness, colorability, and appearance. In particular, Examples 1 and 2 using PTFE having a low crystallinity for the surface layer 4 were found to be particularly preferable since the evaluation results of the coil work resistance were excellent.

  On the other hand, both Experimental Example 4 in which the lower layer 3 was made of PTFE and 12% of pigment and Experimental Example 5 made of PAI and 12% of the pigment were low in coil work resistance and were rejected. In Experimental Example 5, delamination occurred during coil processing.

  Further, in Experimental Example 6 in which the lower layer 3 is made of PTFE + PAI and the surface layer 4 is made of PTFE having a low crystallinity and 12% of the pigment, the coil work resistance, the slipping property, and the colorability are acceptable (or excellent). However, the surface was flawed and the appearance was rejected.

  Further, in Experimental Example 7 constituted by only one layer of PTFE + PAI and 12% of pigment, the slipperiness was insufficient, and the friction with the processing jig of the pin coiling device became tight.

  From the above, in order to provide a fluorine-coated wire that satisfies the required performance for all of coil resistance, slipperiness, colorability, and appearance, the lower layer formed of the mixture defined in the present invention, and the PTFE, It has been found that a two-layer structure including a surface layer formed of a resin having a main component as a main component may be used.

  In addition, this invention is not limited to said form. All modifications within the scope equivalent to the scope of the claims are included.

  The present invention can be applied to a guide wire or the like for guiding a catheter to be inserted into a blood vessel or trachea in the medical field, and has excellent slipperiness, visibility, and resistance to coiling that have not been realized so far. A fluorine-coated wire for medical use that can satisfy these requirements simultaneously is provided.

1 Fluorine coated wire 2 Core wire 3 Lower layer 4 Surface layer

Claims (7)

A metal thin wire, a lower layer covering the metal thin wire, and a surface layer covering the lower layer,
The lower layer is constituted by a mixture in which a pigment containing 5% by mass or more of the resin is dispersed in a resin containing, as a main component, an engineering plastic excellent in adhesiveness with a fluororesin and the fine metal wire,
A fluorine-coated wire, wherein the surface layer is made of a resin mainly composed of polytetrafluoroethylene.   2. The fluorine-coated wire according to claim 1, wherein a mass ratio of the fluororesin and the engineering plastic constituting the lower layer is 1: 9 to 9: 1.   The fluorine-coated wire according to claim 1 or 2, wherein the engineering plastic constituting the lower layer is polyamideimide or polyethersulfone.   The fluororesin constituting the lower layer is selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and mixtures thereof. The fluorine-coated wire according to claim 3.   The fluorine-coated wire according to any one of claims 1 to 4, wherein the polytetrafluoroethylene constituting the surface layer is polytetrafluoroethylene having a low crystallinity.   The fluorine-coated wire according to claim 5, wherein the polytetrafluoroethylene having a low crystallinity is heated to 340 ° C. or higher and baked, and then cooled at a rate of 30 ° C./second or higher. After immersing a metal fine wire in a resin containing as a main component an engineering plastic excellent in adhesion to a fluororesin and a metal fine wire, and a dispersion in which 5% by mass or more of the pigment is dispersed or dissolved in a dispersion medium with respect to the resin A lower layer forming step of drying and forming a lower layer;
Formation of a surface layer that forms a surface layer that covers the lower layer by immersing the thin metal wire formed with the lower layer in a dispersion in which resin particles containing polytetrafluoroethylene as a main component are dispersed in a dispersion medium. Process,
Firing after forming the surface layer, fusing the lower layer fluororesin and resin particles containing the polytetrafluoroethylene of the surface layer as a main component, and a coiling step of processing the fired metal wire into a coil shape The manufacturing method of the fluorine coat wire which has.

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