JP5280055B2 - Shielded wire - Google Patents

Description

The present invention relates to a shielded wire, and more particularly to a coaxial cable used as a signal transmission line of a high-frequency component such as an information communication device, a communication terminal device, or a measuring device that requires excellent high-frequency characteristics.

In recent years, there is an increasing demand for reducing the diameter of a coaxial cable, particularly a coaxial cable. This is a requirement accompanying further downsizing of information communication devices and communication terminal devices. Therefore, as a shield layer disposed on the outer periphery of the insulating resin layer (a dielectric layer made of a fluororesin) of the cable, a metal plating layer that can be made thinner than a metal braided layer or a horizontal winding layer that has been conventionally used is used. The strategy to adopt is attracting attention.

However, the insulating resin layer originally has a problem that the metal plating layer hardly adheres. Therefore, the present applicant has previously proposed a measure for fixing the insulating resin layer and the metal plating layer (for example, see Patent Document 1). According to this proposal, an adhesive resin film such as low-melting modified nylon is first disposed on the outer peripheral surface of the insulating resin layer, and an electroless metal plating layer is further disposed on the outer peripheral surface of the resin film. An electrolytic metal plating layer is formed on the outer peripheral surface of the electroless metal plating layer. In this case, the adhesive resin film is employed to promote the deposition of electrolytic metal.

The above coaxial cable appears to have a stable structure. However, this coaxial cable cannot withstand the stress caused by repeated bending, and is liable to cause a peeling phenomenon between layers and a cracking phenomenon of an electrolytic plating layer. This is due to the limit of the adhesive ability of the adhesive resin film and the insufficient ability to deposit metal against plating. And such a peeling phenomenon leads to the quality problem of the coaxial cable that the conduction state is interrupted.

JP 2007-335124 A

Accordingly, an object of the present invention is to provide improved peel resistance to a shielded electric wire having a metal plating layer as a shield layer.

The present inventor can solve the above-mentioned problems at once by adopting, as an adhesive layer, a triazine dithiol derivative exhibiting bidirectional chemical adhesive ability instead of the nylon adhesive resin film in the above proposal. It came. Here, the bidirectional chemical adhesiveness means a property that the adhesive layer is chemically bonded to each of the insulating resin layer , the elastic body layer, and the metal plating layer.

According to the present invention, in a shielded electric wire in which an elastic body layer is provided on the outer periphery of an insulating resin layer covering a conductor, and a metal plating layer is disposed as a shield layer, a molecular adhesive having an alkoxy group and a triazine dithiol group (hereinafter referred to as “a”) , Simply abbreviated as “molecular adhesive”) as an adhesive layer having a first chemical bond between the insulating resin layer and the elastic layer, and further between the elastic layer and the electroless metal plating layer. A shielded electric wire is provided which is interposed as an adhesive layer having a second chemical bond.

The adhesive layer of the shielded electric wire of the present invention is composed of a molecular adhesive in which both the insulating resin layer and the elastic body layer, and both the elastic body layer and the electroless metal plating layer are chemically bonded to each other. This eliminates the problem of peeling off.

Hereinafter, the present invention will be described with reference to the accompanying drawings in the case of a coaxial cable.

FIG. 1 is a side view showing a reference embodiment of a coaxial cable according to the present invention. In the figure, (1) is the inner conductor, (2) is the insulating resin layer (dielectric layer) disposed on the outer peripheral surface of the inner conductor (1), and (3) is the outer peripheral surface of the insulating resin layer (2). (4) is an electroless metal plating layer formed on the outer peripheral surface of the adhesive layer (3), and (5) is a sheath layer disposed on the outer periphery of the electroless metal plating layer (4). It is.

A characteristic of this coaxial cable is that a molecular adhesive having an alkoxy group and a triazinedithiol group is applied between the fluororesin dielectric layer (2) and the electroless metal plating layer (4), In other words, an adhesive layer (3) chemically bonded to is interposed. By doing so, the insulating resin layer (2), the adhesive layer (3), and the electroless metal plating layer (4) are three-united and chemically bonded, eliminating the problem of peeling of the electroless metal plating layer against repeated bending. Is done.

The molecular adhesive used in the present invention is preferably the following general formula (1):

(In the formula, R ₁ represents H— or CH ₃ —, C ₂ H ₅ —, nC ₃ H ₇ —, CH ₂ ═CHCH ₂ —, n—C ₄ H ₉ —, C ₆ H ₅ —, C ₆ H ₁₁ -, _{R 2} is _{-CH 2 CH 2 -, - CH} 2 CH 2 CH 2 -, - CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 -, - CH 2 CH 2 CH 2 CH 2 CH 2 CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ —, —CH ₂ CH ₂ SCH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ SCH ₂ CH ₂ CH ₂ —, —CH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ — _{, - (CH 2 CH 2)} 2 NCH 2 CH 2 CH 2 -, - C 6 H 4 -, - C 6 H 4 C 6 H 4 -, - CH 2 C 6 H 4 CH 2 -, - CH 2 CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH _{2 -, - CH 2 CH 2 OCONHCH} 2 CH 2 CH 2 -, - CH 2 CH 2 NHCONHCH 2 CH 2 CH 2 -, - (CH 2 CH 2) 2 CHOCONHCH 2 CH 2 CH 2 -, X is H-, CH _{3 -, C 2 H 5 -} , n-C 3 H 7 -, i-C 3 H 7 -, n-C 4 H 9 -, i-C 4 H 9 -, t-C 4 H 9 -, Y is _{CH 3 O-, C 2 H 5} O-, n-C 3 H 7 O-, i-C 3 H 7 O-, n-C 4 H 9 O-, i-C 4 H 9 O-, t -C ₄ H ₉ O-, n is an integer of 1 to 3, M is represented by H or Li, Na, K, it is Ce.).

In the above general formula, examples of each compound in the case of n = 1 to 3 include the following.

For n = 3:
N-trimethoxysilylethylamino-1,3,5-triazine-2,4-dithiol, N-triethoxysilylpropylamino-1,3,5-triazine-2,4-dithiol, N-tripropoxyoxysilyl Propylamino-1,3,5-triazine-2,4-dithiol, and N-tributoxysilylpropylamino-1,3,5-triazine-2,4-dithiol.

For n = 2:
N-dimethoxymethylsilylethylamino-1,3,5-triazine-2,4-dithiol, N-diethoxyethylsilylpropylamino-1,3,5-triazine-2,4-dithiol, N-dipropioxy Propylsilylpropylamino-1,3,5-triazine-2,4-dithiol, and N-dibutoxybutylsilylpropylamino-1,3,5-triazine-2,4-dithiol.

When n = 1:
N-methoxydimethylsilylethylamino-1,3,5-triazine-2,4-dithiol, N-ethoxydiethylsilylpropylamino-1,3,5-triazine-2,4-dithiol, N-propoxydipropyl Silylpropylamino-1,3,5-triazine-2,4-dithiol, and N-butoxydibutylsilylpropylamino-1,3,5-triazine-2,4-dithiol.

FIG. 2 shows an adhesion model in the case of n = 3 (FIG. 2-a), n = 2 (FIG. 2-b), and n = 1 (FIG. 2-c). In the case of n = 3 (FIG. 2-a), the molecular adhesive has a three-dimensional structure while being ether-bonded to the insulating resin layer of the covered electric wire. In the case of n = 2 (FIG. 2-b), the molecular adhesive takes a dimer structure while being ether-bonded to the insulating resin layer of the covered electric wire. In the case of n = 1 (FIG. 2-c), the molecular adhesive is ether-bonded to the insulating resin layer of the covered electric wire. What is common to these drawings is that the SH group of the molecular adhesive is ionically bonded to the plating catalyst of the electroless metal plating layer.

Some of these compounds are described in Journal of the Adhesion Society of Japan, Vol. 43 No. 6 describes a molecular adhesive (nano thin film order) for bonding metal, plastic, and ceramic materials. However, this document does not show the concept of chemically bonding the insulating resin layer and the electroless metal plating layer by applying the polyfunctionality and selective reactivity of these compounds to a shielded wire.

Basic structure of the shielded wire of the present invention is formed through the following A~E steps.
A. Forming an insulating resin layer on the outer periphery of the conductor; A step of generating OH groups as a pretreatment on the surface of the insulating resin layer;
C. Reacting the generated OH group with the alkoxy group of the molecular adhesive;
D. A step of supporting an electroless metal plating catalyst on the surface of the molecular adhesive after the reaction;
And E.E. Depositing an electroless plating layer on the supported catalyst;

In Step A, the insulating resin layer (2) is extrusion coated on the outer periphery of the fine metal wire to be the conductor (1) to obtain the electric wire (a). As the metal thin wire at this time, a single wire or a stranded annealed copper wire or a copper-coated steel wire having a diameter of about 0.01 to 0.2 mm is used. Moreover, as resin which comprises an insulating resin layer (2), a fluororesin and silicone rubber are suitable. Examples of the former include tetrafluoroethylene / hexafluoropropylene (FEP) and tetrafluoroethylene / perfluoroalkoxyethylene copolymer (PFA). Examples of the latter include millable silicone rubber and liquid silicone rubber.

In step B, the outer surface of the insulating resin layer (2) is subjected to known corona discharge, tetraetch treatment or SA treatment to obtain an electric wire (b) having surface OH groups. Further, in step C, the surface OH group and the alkoxy group of the molecular adhesive are reacted. At this time, the alkoxy group is first hydrolyzed, and then an ether bond is formed by a dehydration condensation reaction with the surface OH group. For this purpose, the wire (b) may be immersed in a solution of molecular adhesive at 15 ° C. to 90 ° C. for about 1 second to 15 minutes. The electric wire (c) that has been subjected to the dehydration condensation treatment is taken out of the immersion liquid and further subjected to treatment at 40 ° C. to 250 ° C. for about 1 minute to 20 minutes. Thereafter, the unreacted molecular adhesive is washed and removed.

Here, the molecular adhesive solution is water, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate and ethyl benzoate, ethers such as dibutyl ether and anisole, or benzene. Or a mixture of aromatic hydrocarbons such as toluene or a single solvent. The concentration of the molecular adhesive at this time may be adjusted in the range of 0.01 wt% to 1 wt%.

In step D, an electroless metal plating catalyst is supported on the surface of the molecular adhesive chemically bonded to the insulating resin layer (2). For this purpose, the electric wire (c) may be immersed in an aqueous solution of a plating catalyst such as a palladium salt, a platinum salt, a silver salt, tin chloride, or an amine complex. These catalysts are used alone or in combination. The catalyst concentration varies somewhat depending on the type of the catalyst, but generally it may be in the range of 0.5 wt% to 5 wt%. The immersion conditions may be 15 ° C to 70 ° C for about 30 seconds to 60 minutes. During the dipping process, the plating catalyst is ionically bonded to the SH group of the molecular adhesive. Thereafter, the electric wire (d) carrying the catalyst is taken out of the immersion liquid and washed.

In step E, which is the final step, a shielded electric wire with an electroless metal plating layer is completed. That is, the electroless metal plating layer (4) as a shield layer is formed by immersing the electric wire (d) in an electroless plating bath and depositing a metal on the catalyst ionically bonded to the SH group. At this point, the molecular adhesive has been converted into an adhesive layer (3) in which the insulating resin layer (2) and the electroless metal plating layer (4) are chemically bonded. The electroless plating bath may be any bath commonly used in this field. In other words, the bath contains a metal salt and a reducing agent as main components and, as necessary, an auxiliary agent that extends the life of the electroless plating bath or increases the reduction efficiency. As the metal salt, a salt of gold, silver, copper, nickel, cobalt or the like is used. As the reducing agent, sodium dihydrogen phosphate, hydroxylamine, N, N ethylglycine or the like is used, and as the auxiliary agent, citrate, tartrate or EDTA is used. Each of these metal salts, reducing agents and auxiliaries is provided in a concentration range of 0.01 wt% to 2 wt%.

In order for the electroless metal plating layer (4) to have a shielding function, it is advantageous to adjust the plating film thickness within a range of 0.01 μm to 30 μm. As the electroless metal plating layer (4), a copper plating layer having a film thickness of 0.05 μm to 5 μm is particularly preferable. At this time, if a co-deposition phenomenon is utilized in the presence of a small amount of Ni ions in the electroless metal plating bath, a plating film with improved stress followability can be obtained.

The outer periphery of the electroless metal plating layer (4) is covered with a sheath layer or a protective layer (5) as necessary. The sheath layer (5) is preferably coated by melt extrusion molding of a thermoplastic resin, preferably a fluororesin such as tetrafluoroethylene / perfluoroalkoxyethylene copolymer (PFA).

Furthermore, in another aspect of the present invention, an electrolytic metal plating layer may be placed on the outer peripheral surface of the electroless metal plating layer (4) before the sheath layer (5) is applied. When this electrolytic metal plating layer is formed, a normal plating prescription such as copper sulfate electroplating or copper cyanide electroplating may be employed. The film thickness of the electrolytic metal plating layer at this time is determined in consideration of the shielding characteristics and the flexibility of the coaxial cable. In general, the inner electroless metal plating layer may be adjusted in a range of 0.01 to 5 μm, and the outer electroless metal plating layer may be adjusted in a range of 0.01 to 30 μm. In this case, with the copper sulfate electroplating formulation, a plated film having excellent spreadability and bending resistance can be obtained.

In the present invention, intended to further improve flexibility of the shielded wire, an elastic layer Ru provided between the insulating resin layer of the coated electric wire and (2) an electroless metal plating layer (4). As such an elastic layer, a three-dimensional elastic body having a glass transition point of room temperature or less, for example, silicone rubber or fluororubber is used.

FIG. 3 shows an adhesion model in this embodiment. Here, the interface between the insulating resin layer (2) and the adhesive layer (3) of the covered electric wire is chemically bonded by an ether bond as in the case of FIG. 2, and the interface between the adhesive layer (3) and the inside of the elastic layer. Reacts with the thiol group of the adhesive layer (3) and the carbon radicals generated during the crosslinking of the elastic layer, and a chemical bond is formed between the adhesive layer (3) and the elastic layer. An additional adhesive layer (3) is disposed on the outer periphery of the elastic layer. First, the outer surface of the elastic layer is subjected to well-known corona discharge, tetraetch treatment or SA treatment to generate surface OH groups. Further, the surface OH group is reacted with the alkoxy group of the molecular adhesive. At this time, the alkoxy group is first hydrolyzed, and then an ether bond is formed by a dehydration condensation reaction with the surface OH group. The interface between the additional adhesion layer (3) and the electroless metal plating layer (4) is chemically bonded by ionic bonding as in the case of FIG.

[ Reference Example 1]
First, an electric wire (a) composed of a conductor (1) and an insulating resin layer (2) was prepared. In this case, a thin metal wire having a twisted outer diameter of 0.075 mm obtained by twisting seven tin-plated copper alloy wires having a strand diameter of 0.025 mm is used as the inner conductor (1), and this outer peripheral surface is covered with PFA. Extrusion coating was performed at a thickness of 62.5 μm to obtain a fluororesin dielectric layer to be an insulating resin layer (2) (step A).

Subsequently, SA treatment was applied to each of the three electric wires (a) to obtain an electric wire (b) in which surface OH groups were generated (step B).

Furthermore, 0.1 g / L ethanol solution of molecular adhesive was made for the electric wire (b), and the electric wire (b) was immersed in each solution. The immersion conditions were 10 minutes at 25 ° C. Thereafter, heat treatment was applied at 200 ° C. for 10 minutes, and unreacted molecular adhesive was washed and removed from the heat-treated electric wire (c). The structure of the molecular adhesive used at this time is as follows: R ₁ = —H, R ₂ = —CH ₂ CH ₂ CH ₂ —, Y = C ₂ H ₅ O—, M = —H, and n = 3.

Next, an electroless metal plating catalyst was supported on the electric wire (c) (step D). As the catalyst treatment liquid, an electric wire (d) carrying the catalyst was obtained by immersing in a catalyst treatment liquid containing palladium chloride (PdCl ₂ ) at a concentration of 0.5 wt% to 5 wt% at 70 ° C. for 15 minutes. The electric wire (d) taken out from the immersion liquid was washed with a 1 wt% sulfuric acid aqueous solution.

Further, the wire (d) is immersed in an electroless plating bath (vessel temperature 32 ° C.) for 5 minutes, and then dried and solidified to form an electroless metal plating layer (4) having a film thickness of 0.1 μm. A cable (e) was obtained (Step E). At this point, the molecular adhesive has been converted into an adhesive layer (3) in which the insulating resin layer (2), which is a fluororesin dielectric layer, and the electroless metal plating layer (4) are chemically bonded. The electroless plating solution was prepared by adding a potassium sodium tartrate aqueous solution previously made alkaline to a copper sulfate aqueous solution to which a reducing agent was added. At this time, the copper ion concentration was 2 g / L, the reducing agent amount was 2 g / L, the sodium hydroxide concentration was 2 g / L, and the pH of the aqueous solution was 12.4. The plating conditions were a liquid temperature of 32 ° C. and an immersion time of 5 minutes.

[ Reference Example 2]
On the electroless metal plating layer (4) prepared in Reference Example 1, a metal plating layer having a thickness of 3 μm was further added to obtain a coaxial cable (f). The electrolytic solution at this time was a 4 wt% copper sulfate solution, the current density was 1.5 A / dm ² , and the energization time was 20 minutes.

[Comparative Example 1]
The Example of patent document 1 was reproduced. That is, “AQ nylon” (manufactured by Toray Industries, Inc.) is sprayed on the outer peripheral surface of the fluororesin dielectric layer (2) of the electric wire (a) used in the reference example as an adhesive resin having medium adhesive ability. An adhesive resin film having a film thickness of 0.1 μm was formed. The liquid temperature at this time was 20 ° C., and the drying conditions after coating were a drying temperature of 50 ° C. and a drying time of 5 minutes. Next, the electric wire provided with the adhesive resin film was dipped in an electroless plating tank (tank temperature 32 ° C.) for 5 minutes, dried and solidified, and an electroless plating layer (4) having a thickness of 0.1 μm. Formed. At this time, an electroless plating solution was prepared by adding a potassium sodium tartrate aqueous solution previously made alkaline to a copper sulfate aqueous solution to which a reducing agent was added. At this time, the copper ion concentration was 2 g / L, the reducing agent amount was 2 g / L, the sodium hydroxide concentration was 2 g / L, and the pH of the aqueous solution was 12.4. The plating conditions were a liquid temperature of 32 ° C. and an immersion time of 5 minutes. Further, an electrolytic metal plating layer having a thickness of 3 μm was applied to the electric wire provided with the electroless plating layer. The electrolytic solution at this time was a 4 wt% copper sulfate solution, the current density was 1.5 A / dm ² , and the energization time was 20 minutes.

Each coaxial cable thus obtained was bent at a self-diameter and a diameter of 6 mm to confirm the adhesion of the plating. 4-a (self diameter) and 4-b (diameter 6 mm) of the surface photograph after bending of Reference Example 1 and FIG. 5-a (self-diameter) of the surface photograph after bending of Comparative Example 1 are shown. FIG. 5-b (diameter 6 mm).

As can be seen from FIG. 4, in the reference example 1, peeling of the plating layer is not recognized, but, as can be seen from FIG. 5, in the comparative example 1, the plating layer is peeled off.

Next, in order to measure the adhesion of plating, the following sheet samples were prepared.

First, a PFA resin sheet having a length of 100 mm, a width of 50 mm, and a thickness of 10 mm was prepared, and each of the molecular adhesive of Reference Example 1, the adhesive of Comparative Example 1, and the nylon adhesive of Comparative Example 3 was applied on each sheet. Then, an electroless plating layer having a thickness of 0.1 μm was formed thereon, and an electrolytic plating layer having a thickness of 40 μm was further formed thereon, thereby preparing two types of four-layer sheets. The formulations at this time were in accordance with Reference Example 2 and Comparative Example 1, respectively.

Each sheet thus obtained was subjected to a peeling test based on JISZ0237 (180 degree peeling adhesion measurement) to confirm the degree of adhesion. The results are shown in Table 1.

As can be seen from Table 1, in Reference Example 1, compared to Reference Example 2, the adhesion was improved 10 times. This is because the molecular adhesive having an alkoxy group and a triazine dithiol group is interposed as an adhesive layer chemically bonded to the electroless metal plating layer and the insulating resin layer.

[ Reference Example 3]
A coaxial cable was obtained in the same manner as in Reference Example 1 using the molecular adhesive shown in Table 2. For each coaxial cable, the surface condition and adhesion of the plating were confirmed, and none of them was inferior to that of Reference Example 1.

Since the shielded electric wire of the present invention exhibits excellent high frequency characteristics and shield characteristics while being easily reduced in diameter, it is useful not only for information communication equipment, communication terminal equipment, and measuring equipment, but also for small electronic equipment.

The side view which shows the reference Example of the shielded electric wire which concerns on this invention. The adhesion model figure in the shield electric wire of FIG. Adhesive model diagram definitive in this onset Akira. The SEM photograph after the bending process of the shielded electric wire which concerns on the reference Example of this invention. SEM photograph after bending of conventional shielded wire.

Explanation of symbols

1 Conductor 2 Insulating resin layer 3 Adhesive layer chemically bonded to both insulating resin layer and electroless metal plating layer 4 Electroless metal plating layer 5 Sheath layer

Claims (9)

An elastic layer provided on the outer periphery of the insulating resin layer to cover the conductive, yet shielded cable arranged an electroless metal plating layer as a shielding layer, the molecular adhesive having a alkoxy group and a triazine thiol group, insulating resin layer and as an adhesive layer in which the first chemical bond between the elastic body layer, further as an adhesive layer in which the second chemical bond between the elastic body layer and the electroless metal plating layer, interposed respectively Shielded electric wire characterized by The molecular adhesive is represented by the general formula (1):
(In the formula, R ₁ represents H— or CH ₃ —, C ₂ H ₅ —, nC ₃ H ₇ —, CH ₂ ═CHCH ₂ —, n—C ₄ H ₉ —, C ₆ H ₅ —, C ₆ H ₁₁ -, _{R 2} is _{-CH 2 CH 2 -, - CH} 2 CH 2 CH 2 -, - CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 -, - CH 2 CH 2 CH 2 CH 2 CH 2 CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ —, —CH ₂ CH ₂ SCH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ SCH ₂ CH ₂ CH ₂ —, —CH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ — _{, - (CH 2 CH 2)} 2 NCH 2 CH 2 CH 2 -, - C 6 H 4 -, - C 6 H 4 C 6 H 4 -, - CH 2 C 6 H 4 CH 2 -, - CH 2 CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH _{2 -, - CH 2 CH 2 OCONHCH} 2 CH 2 CH 2 -, - CH 2 CH 2 NHCONHCH 2 CH 2 CH 2 -, - (CH 2 CH 2) 2 CHOCONHCH 2 CH 2 CH 2 -, X is H-, CH _{3 -, C 2 H 5 -} , n-C 3 H 7 -, i-C 3 H 7 -, n-C 4 H 9 -, i-C 4 H 9 -, t-C 4 H 9 -, Y is _{CH 3 O-, C 2 H 5} O-, n-C 3 H 7 O-, i-C 3 H 7 O-, n-C 4 H 9 O-, i-C 4 H 9 O-, t -C ₄ H ₉ O-, shielded wire according to claim 1 n is an integer of 1 to 3, M is the H or Li, Na, K, represented by a Ce.). The first is a chemical bond, bond by reaction with the SH group of a carbon radical and Formula (1) of the elastic layer, and the surface OH groups of the general formula of the insulating resin layer between the alkoxy groups of (1) The shielded electric wire according to claim 2, which is an ether bond. The second chemical bond is an ionic bond between the electroless metal plating catalyst and the SH group of the general formula (1), and between the surface OH group of the elastic layer and the alkoxy group of the general formula (1). The shielded electric wire according to claim 2 or 3, which is an ether bond. The shielded electric wire according to any one of claims 1 to 4, wherein the insulating resin layer is a fluororesin layer. The shielded electric wire according to any one of claims 1 to 4, wherein the insulating resin layer is a silicone rubber layer. The shielded electric wire according to any one of claims 1 to 6, wherein an electrolytic metal plating layer is placed on the electroless metal plating layer. The shielded electric wire according to any one of claims 1 to 7, wherein the elastic layer is made of a three-dimensional elastic body having a glass transition point of room temperature or lower. The shielded electric wire according to claim 8, wherein the three-dimensional elastic body is silicone rubber.