JP6291449B2 - Plating method - Google Patents

Description

The present invention relates to a plating method .

  Conventionally, it has been studied to apply metal plating to carbon fibers. However, the carbon fiber has a problem that the wettability with the plating solution is poor, and the metal plating attachment and adhesion are poor. Then, the method of adjusting the wettability of the carbon fiber surface by apply | coating alkali degreasing liquid to carbon fiber is proposed (for example, refer patent document 1).

JP 2007-186823 A

  However, the carbon fiber whose wettability is adjusted by the method described in Patent Document 1 improves the adhesion around the plating (plating precipitation property) and adhesion, but the mechanical strength is lowered by alkali. It was.

The present invention has been made to solve such conventional problems, and the object of the present invention is to provide a plating method capable of improving the plating precipitation and adhesion without reducing the mechanical strength. Is to provide.

  The plating method of the present invention is a plating method for performing metal plating on carbon fibers, and includes a first step in which carbon fibers are introduced into a treatment tank in which no organometallic complex is introduced, and carbon fibers in the first step. A second step of supplying carbon dioxide brought into a supercritical state to the treatment tank into which carbon dioxide has been charged; and the treatment of carbon fiber after a predetermined time has elapsed since the supply of carbon dioxide brought to the supercritical state in the second step And a fourth step of performing metal plating on the carbon fiber extracted in the third step by electroplating.

  The present inventor can change the surface oxygen content of carbon fiber by exposing the carbon fiber to carbon dioxide in a supercritical state, and the surface oxygen content can be 0.097 or more and 0.138 or less. I found. Therefore, according to the plating method of the present invention, carbon fibers having the surface oxygen amount as described above are manufactured in the first to third steps, and then electroplating is performed in the fourth step. It was found that metal plating can be applied. Therefore, it is possible to provide a plating method capable of performing appropriate metal plating by improving plating precipitation and adhesion without reducing mechanical strength.

ADVANTAGE OF THE INVENTION According to this invention, the plating method which can improve plating precipitation property and adhesiveness, without reducing mechanical strength can be provided.

It is a wire harness containing the carbon fiber which concerns on embodiment of this invention. It is sectional drawing which shows the detail of the carbon fiber which concerns on embodiment of this invention, (a) The cross section of carbon fiber is shown, (b) has shown the electric wire which uses plated fiber as a conductor part. It is the schematic for demonstrating the plating method which concerns on this embodiment. It is a graph which shows an Example and a comparative example.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. In addition, this invention is not limited to embodiment shown below, In the range which does not deviate from the meaning, it can change suitably.

  FIG. 1 is a wire harness including carbon fibers according to an embodiment of the present invention. As shown in FIG. 1, the wire harness WH is a bundle of a plurality of electric wires W, and at least one of the plurality of electric wires W is an electric wire 1 containing carbon fiber described in detail below. For example, as shown in FIG. 1, such a wire harness WH may be provided with connectors C at both ends of the electric wire W, or may be wound with a tape (not shown) to collect a plurality of electric wires W. Good. Moreover, the wire harness WH may be provided with exterior components (not shown), such as a corrugated tube.

  FIG. 2 is a cross-sectional view showing details of the carbon fiber according to the embodiment of the present invention, in which (a) shows a cross section of the carbon fiber, and (b) shows an electric wire having a plated fiber as a conductor portion.

  As shown in FIG. 2A, the carbon fiber 10 is a fiber made by carbonizing an acrylic fiber or pitch (by-products such as petroleum, coal, coal tar, etc.) at a high temperature. Since such carbon fiber 10 has electrical conductivity, it can be used for signal lines and the like. However, when the electrical conductivity is insufficient, metal plating 20 may be applied as shown in FIG. is there. Copper plating is preferable as the metal plating 20 for supplementing such conductivity. However, copper has poor wettability with the carbon fiber 10, and even if electroplating is performed, plating deposition and adhesion are poor.

Therefore, the carbon fiber 10 according to the present embodiment employs a carbon fiber exposed to supercritical carbon dioxide, and the surface oxygen content is different from that of the conventional carbon fiber. Here, the surface oxygen amount referred to in the present embodiment is a value obtained by interrupting the O _1S peak intensity measured by X-ray photoelectron spectroscopy with the C _1S peak intensity measured by the same spectroscopy (O _1S / C _1S ). . The more the surface of the carbon fiber 10 is oxidized, the higher the O _1S peak intensity measured by the X-ray photoelectron spectroscopy, and therefore the value of the surface oxygen amount tends to increase.

  Here, it is known that the number of surface oxygen atoms and the number of acidic functional groups increase at substantially the same rate. In addition, acidic functional groups are believed to contribute to interfacial adhesion. In the carbon fiber 10 according to the present embodiment, the surface oxygen amount is 0.097 or more and 0.138 or less. This is because if the surface oxygen content is less than 0.097, the adhesion to copper is extremely reduced. Further, if the surface oxygen amount exceeds 0.138, the surface oxygen of the carbon fiber 10 hinders contact with the power feeding portion when performing electroplating, and it becomes difficult for a current to flow to the carbon wire 10 and plating deposition is poor. It is to become.

  As shown in FIG. 2B, in the wire harness WH according to the present embodiment, the conductor portion 30 is configured by bundling a plurality of plated fibers obtained by applying metal plating 20 to the carbon fibers 10 as described above. The conductor portion 30 is covered with an insulator 40 to form the electric wire 1. In addition, in FIG.2 (b), although there are seven plated fibers, it is not restricted to seven in particular, For example, 100 or more may be bundled. Further, a plurality of the above-described carbon fibers 10 and the above-described carbon fibers 10 and the carbon fibers different from the above (that is, those having a surface oxygen content outside the above range) are added to the plated fibers obtained by applying the metal plating 20 to the carbon fibers 10 as described above. The conductor portion 30 may be configured by being bundled.

  Next, the plating method according to this embodiment will be described. FIG. 3 is a schematic view for explaining the plating method according to the present embodiment. In order to obtain the plating fiber used for the conductor part 30 in this embodiment, first, carbon fiber is thrown in in the processing tank B (1st process). Here, in the first step, it is assumed that the organometallic complex is not charged into the treatment tank B in the present embodiment. This is because even if the organometallic complex is not put into the treatment tank B, predetermined plating precipitation and adhesion can be obtained.

  Next, carbon dioxide in a supercritical state is supplied into the treatment tank B into which the carbon fiber has been charged (second step). And after the carbon dioxide made into the supercritical state is supplied, carbon fiber is taken out from the processing tank B after progress for a predetermined time (third step). Thereby, said carbon fiber 10 which makes surface oxygen amount 0.097 or more and 0.138 or less can be obtained.

  Thereafter, so-called electroplating is performed, and metal plating 20 (copper plating) is performed on the carbon fiber 10 (fourth step).

  Next, examples and comparative examples will be described. FIG. 4 is a chart showing examples and comparative examples. The carbon fiber used was a PAN-based fiber having a fiber diameter of 7 μm. For Example 1 shown in FIG. 4, the supercritical conditions for carbon dioxide were a pressure of 15 MPa, a temperature of 100 ° C., and a time of 60 minutes. Moreover, about Example 2, as supercritical conditions of carbon dioxide, the pressure was set to 15 MPa, the temperature was set to 130 ° C., and the time was set to 60 minutes. Further, in Example 3, as supercritical conditions of carbon dioxide, the pressure was 15 MPa, the temperature was 150 ° C., and the time was 60 minutes. For Example 4, as supercritical conditions for carbon dioxide, the pressure was 15 MPa, the temperature was 200 ° C., and the time was 60 minutes.

  Moreover, about Examples 1-4 which passed the said supercritical process, and the comparative example 1 which has not performed the supercritical process, it electroplated and copper-plated on carbon fiber.

  In FIG. 4, “◯” indicates the case where a favorable result is obtained without unevenness, and “X” indicates the case where an unfavorable result is obtained due to unevenness. Regarding the adhesion, “◯” indicates that the plating was not detached during the water washing after plating, and “X” represents that the plating was detached during the water washing after plating.

  First, the amount of surface oxygen was 0.138 for Example 1, 0.123 for Example 2, 0.103 for Example 3, and 0.097 for Example 4. In Examples 1 to 4 as described above, the plating depositability was “◯” and the adhesion was “◯”. On the other hand, the surface oxygen amount was 0.159 for the comparative example. In such Comparative Example 1, the plating depositability was “x”, and the adhesion was also “x”. In addition, as shown in FIG. 4, the voltage at the time of performing electroplating was 2.0 V in Examples 1 to 4 and Comparative Example 1. The current values were 0.57 A in Example 1, 0.65 A in Example 2, 0.60 A in Example 3, 0.52 A in Example 4, and 0.40 A in Comparative Example 1.

  From the above, carbon fibers having a surface oxygen content of 0.097 or more and 0.138 or less have favorable results when copper plating is performed by electroplating, and can improve plating precipitation and adhesion. I understood.

  Furthermore, as shown in FIG. 4, the carbon fibers according to Examples 1 to 4 and Comparative Example 1 were measured for strength (N / piece) and subjected to structural analysis by Raman spectroscopy. Here, about the intensity | strength, the result of having performed the tensile test of the single fiber based on JISR7606, and measuring the tensile strength at the time of a disconnection is shown. In Raman spectroscopy, in order to confirm the Raman spectrum of the carbon fiber, a laser having a wavelength of 532 nm is irradiated, and the G / D ratio, half-value width, and peak shift of the obtained Raman spectrum are measured. In addition, it shows that crystallinity is so high that a G / D ratio is high. The half width is a value indicating the completeness of the crystal, and the peak shift is a value indicating the distortion of the atomic arrangement.

  As shown in FIG. 4, the strength of the carbon fibers was 0.2 N / fiber for Examples 1 to 4 and Comparative Example 1. Thus, they showed the same value and no difference was found in the mechanical strength.

  Further, for Examples 1 to 4 and Comparative Example 1, the G / D ratio is 0.90 to 0.93, the half width is 110.3 to 111.5, and the peak shift is 1580 to 1584.7. there were. That is, there was no significant difference in these values.

  As described above, no structural change is observed in the carbon fiber depending on the presence or absence of the supercritical treatment (that is, regardless of whether the surface oxygen amount is 0.097 or more and 0.138 or less). There was no decrease in strength.

  Therefore, it turned out that the carbon fiber which concerns on Examples 1-4 can improve plating depositability and adhesiveness, without reducing mechanical strength.

Thus, in the carbon fiber 10 according to the present embodiment, when the surface oxygen amount is 0.097 or more and 0.138 or less, the present inventor improves wettability with respect to metal plating, plating precipitation, and adhesion. It was found that the performance can be improved. Therefore, according to the carbon fiber 10 which concerns on this embodiment, plating precipitation and adhesiveness can be improved by making surface oxygen amount into the said range. In addition , since it is sufficient that the surface oxygen amount is in the above range, it is not necessary to use an alkali, and a decrease in mechanical strength can be suppressed. Therefore, it is possible to provide the carbon fiber 10 that can improve the plating precipitation and the adhesion without reducing the mechanical strength.

  Moreover, according to the wire harness WH which concerns on this embodiment, the plating fiber which gave the metal plating 20 to the carbon fiber 10 described above is made into the conductor part 30, and the electric wire 1 which coat | covered the insulator 40 on this conductor part 30 is carried out. Therefore, it is possible to provide the wire harness WH having the electric wire 1 in which the metal plating 20 is appropriately applied and the plated fiber in which the decrease in the mechanical strength is suppressed is the conductor portion 30.

  Moreover, in the plating method according to the present embodiment, the present inventors can change the surface oxygen amount of the carbon fiber 10 by exposing the carbon fiber 10 to carbon dioxide in a supercritical state. It was found that it can be 0.097 or more and 0.138 or less. Therefore, according to the plating method concerning this embodiment, carbon fiber 10 which has the above surface oxygen amount is manufactured in the 1st-the 3rd process, and after that electroplating is performed in the 4th process, carbon fiber It was found that the metal plating 20 can be suitably applied to 10. Therefore, it is possible to provide a plating method capable of performing appropriate metal plating by improving plating precipitation and adhesion without reducing mechanical strength.

  As described above, the present invention has been described based on the embodiment, but the present invention is not limited to the above embodiment, and may be modified without departing from the gist of the present invention.

WH: Wire harness W: Electric wire 1: Electric wire 10: Carbon fiber 20: Metal plating 30: Conductor portion 40: Insulator

Claims (1)

A plating method for performing metal plating on carbon fiber,
A first step of introducing carbon fiber into a treatment tank in which no organometallic complex is charged;
A second step of supplying carbon dioxide in a supercritical state to the treatment tank into which carbon fibers have been charged in the first step;
A third step in which carbon fiber is taken out of the treatment tank after a predetermined time has elapsed since the carbon dioxide brought into a supercritical state in the second step is supplied;
A fourth step of performing metal plating on the carbon fiber taken out in the third step by electroplating;
A plating method comprising:

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