JP2011034906A - Manufacturing method of coaxial cable, and coaxial cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a coaxial cable which is simple, convenient, and less in environmental load, and the coaxial cable manufactured by the manufacturing method. <P>SOLUTION: The manufacturing method of the coaxial cable 1 includes; an insulating covered wire preparation process of preparing an insulating covered wire 2 having a conductor 10 and an insulating cover layer 20 formed on a surface of the conductor 10; a coating process of coating a paste in which metal particulates are dispersed on the surface of the insulating cover layer 20; and a firing process of forming a shield layer 30 in which the paste is made into a metal film by firing the paste, and of roughening the outer surface of the insulating cover layer 20 by heat generation when firing the metal particulate paste in making the metal film. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a coaxial cable and a coaxial cable. In particular, the present invention relates to a method for manufacturing a coaxial cable including a shield layer made of a sintered body of metal fine particles, and a coaxial cable.

  In recent years, ultrafine coaxial cables have been widely used for medical devices, mobile phones, and the like. For example, a probe for a medical device is configured by bundling several tens to several hundreds of ultra-fine coaxial cables, and next-generation products are required to improve the handleability and transmission characteristics of the cables. To improve the handleability of the cable, it is necessary to reduce the diameter and weight of the ultrafine coaxial cable used for the probe. In order to reduce the diameter and weight of the ultrafine coaxial cable, it is effective to reduce the thickness of the shield layer provided in the ultrafine coaxial cable.

  Conventionally, in an ultra-thin coaxial cable having an insulation coating layer and a shield layer on the outer periphery of the center conductor, a metal is formed on the surface of the insulation coating layer that is made of fluororesin and has a surface roughened layer formed by surface treatment on the surface layer A coaxial cable is known which is composed of a sintered nanoparticle and is provided with a shield layer having a layer thickness of less than 10 μm (see, for example, Patent Document 1). The coaxial cable described in Patent Document 1 can provide a coaxial cable having the above-described configuration and having a shield layer with a layer thickness of less than 10 μm and excellent bending characteristics, that is, winding property.

  Conventionally, as a method of manufacturing a coaxial cable including a method for improving the adhesion between an insulating coating layer made of a fluorine-based resin and a shield layer, an insulator coating process for coating an insulator on the outer periphery of a center conductor, and the insulation An activation treatment process is performed using a sputter etching treatment, excimer laser irradiation treatment, metal sodium-naphthalene complex solution immersion treatment, and the like, and an anchor metal layer is formed on the surface of the insulation that has been activated. A method of manufacturing a coaxial cable is known that includes an electroless plating step for performing an electroplating step and an electroplating step for forming a conductive metal layer on the outer periphery of the formed anchor metal layer (see, for example, Patent Document 2). Since the coaxial cable manufacturing method described in Patent Document 2 manufactures a coaxial cable through the above steps, a coaxial cable with improved flexibility can be obtained.

JP 2006-294528 A JP-A-6-187847

  However, although the coaxial cable described in Patent Document 2 is manufactured by, for example, performing an immersion treatment with a metal sodium-naphthalene complex solution, a large amount of waste liquid is discharged after the immersion treatment, and the load on the environment is large. In addition, in the coaxial cable described in Patent Document 1, it is necessary to subject the insulating coating layer to surface treatment in order to improve the adhesion of the shield layer. Therefore, the manufacturing cost increases with an increase in manufacturing steps, setup operations, and the like. May increase.

  Therefore, the objective of this invention is providing the coaxial cable manufactured by the manufacturing method of the coaxial cable with simple and little environmental impact, and the said manufacturing method.

  In order to achieve the above object, the present invention provides an insulating coated wire preparation step for preparing an insulating coated wire having a conductor and an insulating coating layer formed on the surface of the conductor, and metal fine particles are dispersed on the surface of the insulating coating layer. The coating process for applying the paste, and the paste is fired to form a shield layer in which the paste is turned into a metal film, and the outer surface of the insulating coating layer is roughened by the heat generated when the metal fine particle paste is fired in forming the metal film. A method for manufacturing a coaxial cable comprising a firing step is provided.

  Further, in the method for manufacturing the coaxial cable, in the firing step, a shield layer having a rough surface is formed on the insulating coating layer side, and an outer surface of the insulating coating layer is in contact with the rough surface, whereby the insulating coating layer is formed during firing. It is preferable that irregularities are formed on the outer surface.

  Further, in the method for manufacturing the coaxial cable, the application step can apply a paste containing metal fine particles having convex portions.

  In the method for manufacturing the coaxial cable, the coating step can be performed by applying a paste containing porous metal fine particles.

  The coaxial cable manufacturing method can further include a jacket layer forming step of forming a jacket layer on the surface of the shield layer.

  Moreover, the manufacturing method of the said coaxial cable can also form the shield layer which has a rough surface with a rough average surface roughness rather than the average surface roughness before baking of the outer surface of an insulation coating layer in a baking process.

  In order to achieve the above object, the present invention provides a conductor, an insulating coating layer provided on the surface of the conductor, a shield layer provided on the surface of the insulating coating layer, made of a sintered body of metal fine particles, and a shield layer. The shield layer has an inner surface roughened by a sintered body, and the insulating coating layer has irregularities corresponding to the roughened inner surface on the outer surface. A coaxial cable is provided.

  In the coaxial cable, the unevenness of the insulating coating layer is preferably formed by heat generation when the metal fine particle paste is fired.

  The coaxial cable may further include a mixed layer in which an insulating material constituting the insulating coating layer and a sintered body constituting the shielding layer are mixed at the boundary between the insulating coating layer and the shield layer.

  In the coaxial cable, the average surface roughness Ra of the outer surface of the insulating coating layer is preferably 0.05 μm or more and 2.0 μm or less.

  According to the method for manufacturing a coaxial cable and the coaxial cable according to the present invention, it is possible to provide a method for manufacturing a coaxial cable that is simple and has a low environmental load, and a coaxial cable manufactured by the manufacturing method.

It is sectional drawing of the coaxial cable which concerns on embodiment of this invention. It is a partial section enlarged view of a coaxial cable concerning an embodiment of the invention. It is a figure which shows a part of manufacturing process of the coaxial cable which concerns on embodiment of this invention. It is a fragmentary sectional view of the coaxial cable which concerns on the modification of embodiment of this invention. (A) is sectional drawing of the insulation coating wire which concerns on an Example, (b) is sectional drawing of the cable with a shield layer which concerns on an Example. (A) is a microscope picture of the surface of the insulation coating layer before shield layer formation, (b) is a microscope picture of the surface of the insulation coating layer after peeling off a shield layer after shield layer formation. It is a schematic diagram of the measuring method of adhesive force. It is a schematic diagram from the upper surface side of a use fixed film. It is a figure which shows the measurement result of the adhesive force with respect to the average surface roughness of the outer surface of an insulation coating layer.

[Summary of embodiment]
The manufacturing method of the coaxial cable 1 according to the embodiment is the manufacturing method of the coaxial cable 1 including the shield layer 30 formed by sintering metal fine particles, and the conductor 10 and the insulating coating layer 20 formed on the surface of the conductor 10. An insulating coated wire preparing step for preparing an insulating coated wire 2 having a coating, a coating step for applying a paste in which metal fine particles are dispersed on the surface of the insulating coating layer 20, and a shield in which the paste is baked to form a metal film And a firing step of roughening the outer surface of the insulating coating layer 20 by heat generation during firing of the metal fine particle paste in forming the metal film.

  In addition, the coaxial cable 1 according to the present embodiment includes a conductor 10 and an insulating coating layer 20 provided on the surface of the conductor 10 in the coaxial cable 1 including the shield layer 30 formed by sintering metal fine particles. The shield layer 30 is provided on the surface of the coating layer 20 and made of a sintered body of metal fine particles, and the jacket layer 40 is provided on the surface of the shield layer 30. The shield layer 30 is roughened by the sintered body. The insulating coating layer 20 has irregularities corresponding to the roughened inner surface on the outer surface.

[Embodiment]
FIG. 1 shows an outline of a cross section of a coaxial cable according to an embodiment of the present invention.

(Outline of coaxial cable 1)
The coaxial cable 1 according to the embodiment of the present invention includes a conductor 10, an insulating coating layer 20 provided on the surface of the conductor 10, and a shield layer provided on the surface of the insulating coating layer 20 and made of a sintered body of metal fine particles. 30 and a jacket layer 40 provided on the surface of the shield layer 30. Further, the shield layer 30 according to the present embodiment is formed to have an inner surface (that is, a surface on the insulating coating layer 20 side) roughened by the sintered body. Further, the insulating coating layer 20 is formed with irregularities corresponding to the inner surface of the roughened shield layer 30 on the outer surface (that is, the surface on the shield layer 30 side). In this embodiment, the rough surface of the inner surface of the shield layer 30 has unevenness caused by the unevenness of the sintered metal fine particles, and the unevenness is formed on the outer surface of the insulating coating layer 20 so as to correspond to the unevenness. (In other words, the unevenness on the inner surface of the shield layer 30 is transferred to the outer surface of the insulating coating layer 20 to form the unevenness).

(Conductor 10)
The conductor 10 is formed of a material capable of transmitting an electrical signal, and specifically, is formed of a metal fine wire having a diameter of about several tens of μm. For example, the conductor 10 is formed of a metal material such as copper or a copper alloy, a copper wire having a metal plating applied to its surface, or a copper alloy wire including copper and another metal. In addition, as plating, tin plating, silver plating, and other metal plating can be used. The coaxial cable 1 according to the present embodiment includes one or a plurality of conductors 10 near the center. When a plurality of conductors 10 are provided, the plurality of conductors 10 are preferably twisted together.

(Insulating coating layer 20)
The insulating coating layer 20 is formed of an insulating polymer material, for example, a fluorine resin, and covers the outer periphery of the conductor 10. The insulating coating layer 20 is formed of a material having a melting point higher than the firing temperature when forming the shield layer 30 described later. A rough surface (that is, an uneven surface) is formed on the outer surface of the insulating coating layer 20, that is, the surface in contact with the shield layer 30. This rough surface is caused by local heat generated when the metal fine particle paste constituting the shield layer 30 is fired to form a sintered body when the shield layer 30 is formed in the manufacturing process of the coaxial cable 1 described later. It is formed. Further, from the viewpoint of improving the adhesion between the insulating coating layer 20 and the shield layer 30, the average surface roughness Ra of the outer surface of the insulating coating layer 20 is preferably 0.05 μm or more and 2.0 μm or less.

<Shield layer 30>
The shield layer 30 is formed from a sintered body of metal fine particles. As the metal fine particles, for example, fine particles made of a highly conductive metal material such as silver fine particles, copper fine particles, and gold fine particles can be used. Further, fine particles of an alloy containing a metal material such as silver, copper, or gold can also be used. Furthermore, the shield layer 30 can also be formed from a sintered body obtained by mixing and sintering a plurality of types of metal fine particles (for example, silver fine particles and copper fine particles).

(Jacket layer 40)
The jacket layer 40 is provided on the surface of the shield layer 30. The jacket layer 40 can be formed from a thermoplastic resin such as polyethylene terephthalate, a fluorine resin such as tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), or the like.

(Details of boundary between insulating coating layer 20 and shield layer 30)
FIG. 2 shows an outline of an enlarged partial cross section of the coaxial cable according to the embodiment of the present invention.

  The insulation coating layer 20 included in the coaxial cable 1 has a rough surface 20 a on the outer surface, and the rough surface 20 a is formed including a plurality of concave portions 22 and convex portions 24. The concave portion 22 and the convex portion 24 are formed at positions corresponding to the concave and convex portions of the inner surface 30 a of the shield layer 30 made of the sintered body of the metal fine particles 32. That is, the rough surface 20a is formed to have the concave portion 22 and the convex portion 24 to which the concave and convex portions of the inner surface 30a are transferred.

(Method for manufacturing coaxial cable 1)
FIG. 3 shows an outline of a part of the manufacturing process of the coaxial cable according to the embodiment of the present invention.

  First, an insulation coated wire 2 having a conductor 10 and an insulation coating layer 20 (for example, a resin layer made of a fluororesin) formed on the surface of the conductor 10 is prepared (insulation coating wire preparation step). Next, the prepared insulated wire 2 is set in the delivery device 100. Then, the delivery device 100 continuously delivers the insulation-coated wire 2 toward the metal fine particle application die 110. In the method for manufacturing the coaxial cable 1 according to the present embodiment, the insulation-coated wire 2 is sent toward the metal fine particle coating die 110 in a state where the outer surface of the insulation coating layer 20 is not roughened.

  Subsequently, the metal fine particle application die 110 applies a paste in which the metal fine particles are dispersed on the surface of the insulating coating layer 2 (application process). In the coating step, spherical metal fine particles or non-spherical metal fine particles can be used. The non-spherical metal fine particles are metal fine particles having a convex portion. For example, flaky metal fine particles, needle-shaped metal fine particles, metal fine particles having irregularities on the surface, and the like can be used. Since the non-spherical metal fine particle has an acute-angled region (that is, a convex portion) on the surface thereof that does not have the spherical metal fine particle, the adhesion between the shield layer 30 and the insulating coating layer 20 is further enhanced by the anchor effect. be able to.

  Further, as the metal fine particles, porous metal fine particles can also be used. When the metal fine particles of the porous body are used, the material constituting the insulating coating layer 20 is melted by the heat generated when the metal fine particle paste is fired in the firing step described later, and the melted material enters the pores of the metal fine particles. Thereby, an anchor effect is exhibited and the adhesiveness between the shield layer 30 and the insulating coating layer 20 can be further enhanced.

  The insulating coated wire 2 to which the paste is applied is supplied to the tubular firing furnace 120. The tubular firing furnace 120 forms the shield layer 30 on the surface of the insulating coating layer 2 by firing the paste to form a metal film of the paste. Furthermore, in the present embodiment, along with the formation of the shield layer 30, the outer surface of the insulating coating layer 20 is roughened by local heat generation during the firing of the metal fine particle paste in forming the metal film (firing step).

  Here, the tubular firing furnace 120 can set the firing temperature for each predetermined distance along the longitudinal direction of the insulating coated wire 2. Therefore, the firing temperature in the tubular firing furnace 120 can be raised or lowered stepwise from the side closer to the metal fine particle coating die 110 to the side away from the die. For example, the firing temperature on the side farther from the metal fine particle application die 110 can be made higher than the firing temperature on the side closer to the metal fine particle application die 110 in the tubular firing furnace 120.

  Moreover, when baking the paste which used silver fine particles as metal fine particles, the baking temperature in the tubular baking furnace 120 is set to about 150 degreeC or more and 270 degrees C or less. In this case, when a resin layer made of a fluororesin is used as the insulating coating layer 20, the melting point of the insulating coating layer 20 is higher than the firing temperature. For example, when PFA is used as the fluororesin, the melting point of PFA is 310 ° C., which is higher than the firing temperature. Therefore, the outer surface of the insulating coating layer 20 is not generally roughened by firing in a temperature range of about 150 ° C. or higher and 270 ° C. or lower.

  However, in the present embodiment, the metal fine particles are fired in the temperature range. When the fine metal particles are sintered by this firing, local heat generation occurs between the outer surface of the insulating coating layer 20 and the paste layer containing the fine metal particles. When the temperature due to the heat generation becomes equal to or higher than the melting point of the material constituting the insulating coating layer 20, the outer surface of the insulating coating layer 20 can be locally heated and melted. Thereby, the unevenness | corrugation of the inner surface of the shield layer 30 is transcribe | transferred to the outer surface of the insulating coating layer 20, and the outer surface of the insulating coating layer 20 is roughened.

  That is, in the firing step, the shield layer 30 having a rough surface on the insulating coating layer 20 side is formed by sintering the metal fine particles by firing. When the rough surface is formed on the inner surface of the shield layer 30, the outer surface of the insulating coating layer 20 is in contact with the rough surface of the shield layer 30, so that the outer surface is roughened during firing. Thus, irregularities are formed on the outer surface of the insulating coating layer 20. In other words, in the firing step, the shield formed by forming the shield layer 30 having a rough surface with an average surface roughness that is coarser than the average surface roughness before firing of the outer surface of the insulating coating layer 20 by firing the paste. The rough surface of the layer 30 forms irregularities on the outer surface of the insulating coating layer 20.

  And the cable 3 with a shield layer provided with the shield layer 30 in which the paste is turned into a metal film is discharged from the tubular baking furnace 120 and wound around the winder 130 at a predetermined take-up speed. In addition, control of the take-up speed of the cable 3 with the shield layer and bobbin take-up are performed by the take-up machine 130 and a take-up machine (not shown). And the jacket layer 40 is formed in the surface of the shield layer 30 of this cable 3 with a shield layer (jacket layer formation process). Through the above steps, the coaxial cable 1 according to this embodiment is manufactured.

(Effect of embodiment)
In the method of manufacturing the coaxial cable 1 according to the embodiment of the present invention, the outer surface of the insulating coating layer 20 is roughened simultaneously with the formation of the shield layer 30 made of a sintered body of metal fine particles. It is possible to provide an ultrafine coaxial cable 1 in which the adhesion between the shield layer 30 and the shield layer 30 is improved by a simple method. That is, according to the manufacturing method of the coaxial cable 1 according to the present embodiment, in order to roughen the outer surface of the insulating coating layer 20, a process such as a wet etching process, a dry etching process, an atmospheric pressure plasma process, etc. , Roughening treatment) is not required on the outer surface of the insulating coating layer 20, so that the coaxial cable 1 can be easily manufactured and the environmental load can be reduced to manufacture the coaxial cable 1. As a result, it is possible to provide an ultrafine coaxial cable 1 having excellent bending resistance at a low manufacturing cost.

  Moreover, since the manufacturing method of the coaxial cable 1 which concerns on embodiment of this invention can form the manufacturing process from formation of the insulation coating layer 20 of insulation coating wire, formation of the shield layer 30, and formation of the jacket layer 40 to 1 line. The coaxial cable 1 can be manufactured with high efficiency and reduced manufacturing cost.

[Modification of Embodiment]
FIG. 4 shows an outline of a partial cross section of a coaxial cable according to a modification of the embodiment of the present invention.

  The coaxial cable according to the modification of the embodiment has substantially the same function and configuration as the coaxial cable 1 according to the embodiment except that the mixed layer 50 is formed at the boundary between the insulating coating layer 20 and the shield layer 30. Is provided. Therefore, a detailed description is omitted except for differences.

  In the coaxial cable according to the modification of the embodiment, the insulating material constituting the insulating coating layer 20 and the sintered body constituting the shielding layer 30 are mixed at the boundary between the insulating coating layer 20 and the shield layer 30. A mixed layer 50 is provided. The mixed layer 50 is formed as follows. That is, for example, by setting the firing temperature in the firing step to a temperature higher than the temperature described in the embodiment, for example, 270 ° C. or more, the material constituting the insulating coating layer 20 melted by firing is the sintered body. Flows into the interior. Note that the firing temperature is set to less than 300 ° C. in order to prevent not only the surface of the insulating coating layer 20 made of PFA but also the inside from being softened and the occurrence of cable deformation due to PFA expansion. Thereby, the mixed layer 50 is formed at the boundary between the insulating coating layer 20 and the shield layer 30. By forming the mixed layer 50, the adhesion between the insulating coating layer 20 and the shield layer 30 can be further improved.

  FIG. 5A (a) shows an outline of a cross section of an insulation-coated wire according to the example, and FIG. 5A (b) shows an outline of a cross section of the cable with a shield layer according to the example. 5B (a) shows a micrograph of the surface of the insulating coating layer before the shield layer is formed, and FIG. 5B (b) shows a microscope of the surface of the insulating coating layer after the shield layer is peeled off after the shield layer is formed. Show photos.

  The insulation coated wire 2 according to the example is composed of a central conductor obtained by twisting seven silver-plated copper core wires having an outer diameter φ of 16 μm, and an insulation coating layer 20 made of PFA covering the outer periphery of the central conductor. An insulation-coated wire 2 having D of about 120 μm was prepared. The surface 21 of the insulating coating layer 20 of the insulating coating wire 2 was very smooth as shown in FIG. 5B (a), and the average surface roughness Ra was less than 0.02 μm.

  A shield layer 30 was formed on the surface of the insulating coated wire 2 to manufacture a cable 3 with a shield layer. For forming the shield layer 30, a metal fine particle dispersion paste having a viscosity of 1 Pa · s was used, and silver fine particles were used as the metal fine particles. The average particle diameter of the silver fine particles is 1 μm, and the maximum particle diameter is 2 μm.

  Specifically, the shield layer 30 was formed as follows. First, in the metal fine particle application die 110, the metal fine particle dispersed paste was applied to the surface of the insulating coated wire 2. Then, the insulated coated wire 2 having a layer made of paste was supplied to the tubular firing furnace 120. Here, in the examples, a tubular firing furnace 120 having a length of 9 m and capable of setting a firing temperature every 1 m was used. As the firing temperature, the atmospheric temperature at a position 1 cm away from the central axis of the tubular firing furnace 120 is set to 0.5 m to 8 from the entrance portion where the insulation-coated wire 2 having the paste layer enters the tubular firing furnace 120. 9 points were measured every 1m up to 5m. Specifically, the distance from the entrance to 1 m was set to 150 ° C., and the remaining 8 m was set to 270 ° C.

  The insulation-coated wire 2 having a layer made of paste was supplied to such a tubular firing furnace 120, and the layer made of paste was fired to form the shield layer 30. The shield layer 30 thus obtained had a film thickness t of about 10 μm, a specific resistance of 5 μΩ · cm, and high adhesion to the insulating coating layer 20 made of PFA. And the cable 3 with a shield layer was wound up by the winder 130. In this example, the take-up speed of the cable 3 with the shield layer was set to 20 m / min.

  Here, for the purpose of investigating the cause of the improvement in the adhesion between the insulating coating layer 20 and the shield layer 30, the shield layer 30 of the manufactured cable 3 with the shield layer is peeled off to show the outer surface of the insulating coating layer 20. The surface 21 and the inner surface 30a of the shield layer 30 were observed. As a result, as shown in FIG. 5B (a), although the average surface roughness Ra of the surface 21 of the insulating coating layer 20 before forming the shield layer 30 was less than 0.02 μm and very smooth, First, the surface 21 of the insulating coating layer 20 after the formation of the shield layer 30 was roughened as shown in FIG. 5B (b). The average surface roughness Ra of the surface 21 of the insulating coating layer 20 after the shield layer 30 was formed was 0.25 μm, which was shown to be much larger than that before the shield layer 30 was formed. The average surface roughness Ra of the inner surface 30a of the shield layer 30 was 0.3 μm.

(About the preferable value of the average surface roughness Ra of the surface 21 of the insulating coating layer 20)
A silver-coated wire as a shielded cable 3 having a shield layer 30 formed from a paste containing silver fine particles having different average particle diameters is prototyped, and the adhesion between the insulating coating layer 20 made of PFA and the shield layer 30 Was measured. In the examples, attention was particularly paid to the dependency of the adhesion force on the average surface roughness of the surface of the insulating coating layer 20.

  FIG. 6A shows an outline of a method for measuring the adhesion force, and FIG. 6B shows an outline from the upper surface side of the used fixing film.

  The measurement of the adhesion force was performed by preparing the fixing base 200 and the sample fixing film 210 installed on the fixing base 200 and fixing the sample 1a on the sample fixing film 210. Specifically, 22 prototyped silver-coated wires were arranged and fixed on the sample fixing film 210 as a sample 1a. As shown in FIG. 6B, the region where the silver coated wires are arranged has a width W of about 3 mm and a length L2 of 5 cm. Then, as shown in FIG. 6A, a highly adhesive polyethylene tape (adhesive strength: 40 N / 25 cm) having a width of 3 mm was attached to the upper surface of the sample 1a over a length of 3 cm (see L1 in FIG. 6A).

  Next, the adhesive tape 220 is pulled in the direction of 90 degrees with respect to the surface of the sample 1a at a speed of 10 cm / min, and the width per width W (that is, 3 mm and the width corresponding to 22 silver-coated wires). The tensile load was measured as the adhesion force. When the measured adhesion is 0.6 N / 3 mm or more, it can be determined that the adhesion is sufficient in the coaxial cable manufacturing process. That is, after the shield layer 30 is formed, it can be determined that the shield layer 30 is not damaged when the cable 3 with the shield layer is covered with the material constituting the jacket layer 40 by extrusion.

  FIG. 7 shows the measurement results of the adhesion force with respect to the average surface roughness of the outer surface of the insulating coating layer.

  The horizontal axis represents the average surface roughness Ra of the outer surface of the insulating coating layer 20 made of PFA, and the vertical axis represents the adhesion between the insulating coating layer 20 and the shield layer 30. When the average surface roughness Ra of the outer surface of the insulating coating layer 20 was 0.02 μm or less, the adhesion was less than 0.6 N / 3 mm. However, when the average surface roughness Ra is in the range of 0.05 μm or more and 2.0 μm or less, it was shown that the adhesion strength is very high of 1 N / 3 mm or more. Note that when the average surface roughness Ra was 3.0 μm or more, the adhesion was less than 0.6 N / 3 mm. It was considered that this was caused by the unevenness on the outer surface of the insulating coating layer 20 becoming gentle and the anchor effect being reduced.

  From the above results, when the adhesion between the insulating coating layer 20 and the shield layer 30 is intended to be greater than or equal to a predetermined adhesion force, the average surface roughness Ra of the outer surface of the insulating coating layer 20 is 0.05 μm. It was shown that the thickness is preferably 2.0 μm or less.

  While the embodiments and examples of the present invention have been described above, the embodiments and examples described above do not limit the invention according to the claims. It should be noted that not all combinations of features described in the embodiments and examples are necessarily essential to the means for solving the problems of the invention.

DESCRIPTION OF SYMBOLS 1 Coaxial cable 1a Sample 2 Insulated coated wire 3 Cable with shield layer 10 Conductor 20 Insulated coating layer 20a Rough surface 21 Surface 22 Recessed portion 24 Convex portion 30 Shield layer 30a Inner surface 32 Metal fine particles 40 Jacket layer 50 Mixed layer 100 Sending device 110 Metal Fine particle coating die 120 Tubular firing furnace 130 Winder 200 Fixing base 210 Sample fixing film 220 Adhesive tape

Claims (10)

An insulation coated wire preparation step of preparing an insulation coated wire having a conductor and an insulation coating layer formed on the surface of the conductor;
An application step of applying a paste in which metal fine particles are dispersed on the surface of the insulating coating layer;
Firing the paste to form a shield layer in which the paste is turned into a metal film, and firing the outer surface of the insulating coating layer by heat generated during firing of the metal fine particle paste in forming the metal film; A method for manufacturing a coaxial cable.   In the firing step, the shield layer having a rough surface on the insulating coating layer side is formed, and the outer surface of the insulating coating layer is in contact with the rough surface, whereby the insulating coating layer of the insulating coating layer is in contact with the rough surface. The method for manufacturing a coaxial cable according to claim 1, wherein irregularities are formed on the outer surface.   The method of manufacturing a coaxial cable according to claim 2, wherein the applying step applies the paste containing metal fine particles having convex portions.   The method of manufacturing a coaxial cable according to claim 2, wherein in the applying step, the paste containing porous metal fine particles is applied.   The manufacturing method of the coaxial cable of any one of Claims 1-4 further equipped with the jacket layer formation process which forms a jacket layer in the surface of the said shield layer.   The coaxial cable manufacturing method according to claim 2, wherein the firing step forms the shield layer having the rough surface having an average surface roughness rougher than an average surface roughness before firing of the outer surface of the insulating coating layer. Conductors,
An insulating coating layer provided on the surface of the conductor;
A shield layer provided on the surface of the insulating coating layer and made of a sintered body of metal fine particles;
A jacket layer provided on the surface of the shield layer,
The shield layer has an inner surface roughened by the sintered body,
The said insulation coating layer is a coaxial cable which has the unevenness | corrugation corresponding to the said roughened inner surface on an outer surface.   The coaxial cable according to claim 7, wherein the unevenness of the insulating coating layer is formed by heat generation when the metal fine particle paste is fired. The boundary layer of the said insulating coating layer and the said shield layer is further equipped with the mixed layer in which the insulating material which comprises the said insulating coating layer, and the said sintered compact which comprises the said shield layer are mixed. coaxial cable.   The coaxial cable according to claim 9, wherein an average surface roughness Ra of the outer surface of the insulating coating layer is 0.05 μm or more and 2.0 μm or less.