JPS62177281A - Surface electrolytic treatment of carbon fiber tow - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for surface treatment of carbon fibers.
In detail, it concerns a power supply method for uniformly electrolyzing the surface of carbon fibers.

(Conventional technology) Composite materials made of carbon fiber and various resin matrices are used for aerospace structural materials, automobiles, industrial machinery parts, and sporting goods due to their outstanding properties such as light weight, high strength, and high elasticity. I'm so happy to be done. However, when carbon fibers are used as composite materials, the strength of the carbon fibers themselves is important, but it is also important to improve their adhesion to matrices such as resins, and to improve the strength of the composite material and interlaminar shear strength. extremely important.

In order to improve this adhesion, methods such as vapor phase oxidation, liquid phase oxidation, or electrolytic oxidation of the carbon fiber surface have been proposed, among which anodic oxidation is considered to be useful. (Special Public Showa Riichiko 9t Dar).

By the way, when performing electrolytic oxidation of carbon fibers, it is necessary to supply current to the carbon fibers, and in order to perform a homogeneous electrolytic treatment, it is necessary to apply current evenly to each single yarn of the carbon fiber tow. This is the mold cost.

Therefore, as a power supply method, a non-contact method (in which carbon fiber is passed through an anode in the form of a groove or pipe filled with electrolyte) is proposed.
Special Public Shoq Cuco No. 99112).

A gas-phase roller power supply type in which carbon fibers are stretched between an anode roller provided in the gas phase outside the electrolytic bath and a guide roller provided in the electrolytic bath. ) and a fixed brush method in which the carbon fiber is brought into contact with the electrode brush.

(Problems to be Solved by the Invention) By the way, the non-contact type is effective in suppressing single yarn breakage and fuzz, but because the roller and carbon fiber are not in contact, the electrical resistance is large. needs to be made larger. Therefore, as the amount of power consumption increases, the risk of electric shock also increases. Furthermore, when processing multiple yarns, if the distance between the electrode and the yarn changes due to yarn wobbling or the like, it becomes difficult to uniformly supply power to each yarn.

Furthermore, in the fixed brush method, the carbon fibers come into contact with the fixed electrode and are rubbed, resulting in disadvantages such as single fiber breakage and reduced fuzz strength.

Furthermore, in the gas-phase roller power feeding type, there was a risk that the carbon fibers would fall on the anode roller surface and generate heat (Joule heat), leading to deterioration.

(Means for Solving the Problems) Therefore, the inventors of the present invention have developed a solution to the problems of the gas-phase roller or bar feeding system in order to adopt a roller or par feeding system that is less likely to cause single yarn breakage or decrease in fluff strength. As a result of various studies, we found that the heat generated by the carbon fibers on the roller surface is caused by the large electrical resistance of the contact surface between the four-layer and the fibers, and the non-uniformity of each single yarn. It was discovered that the liquid can be easily removed by interposing a liquid with low electrical resistance, for example, an electrolyte, and based on this knowledge, the present invention was completed.

That is, the present invention is a method in which a carbon fiber tow is immersed in an electrolyte solution, and the carbon fiber is used as an anode to perform surface treatment on the carbon fiber by electrolysis. The present invention resides in a method for surface electrolytic treatment of carbon fiber tow, characterized in that a current is supplied to the carbon fiber tow through the anode by stretching the tow and bringing the tow into contact with each other.

Next, the present invention will be explained based on the drawings.

FIG. 1 is a schematic sectional view of one example of the device used in the present invention, FIG. 2 is a schematic sectional view of another example, FIG. 3 is a schematic sectional view of yet another example, and FIG. 1 is a conventional device. FIG.

/ in the figure is electrolytic N.

- is a cathode plate, 3.3' is a liner, and 1 and 1' are anode rollers.

As shown in Figure 1, a nine-electrode M1 is provided at the bottom.
A power supply tank 3.3' is provided before and after /.

The power supply tanks 3, 3' are provided with anode rollers A, 4' inside the tank, and carbon fiber tow passages tr, r' on the tank wall. Power supply tank 3
．． 3' is filled with a highly electrically conductive liquid such as an electrolytic solution, water, or an alcohol such as methyl alcohol, ethyl alcohol, propylene alcohol, or ethylene glycol, so as to immerse at least a portion of the anode roll. It will be done. The liquid flowing out from the passages g and g' is circulated to the power supply tank 3°3' by using a pump so that the liquid level 7' remains constant. The electrolytic solution flowing out of the carbon fiber tow passages 9, 9' of the electrolytic cell is circulated to the electrolytic cell using a pump so that the liquid level 10 remains constant. In addition to the locations shown in the diagram, the electrolyte circulation locations are on the left and right sides of the shell.
can be on both sides.

Figure 1 shows the case where the power supply tanks J and J' are installed directly on the wall of the electrolytic cell. In this case, since there is no outflow of liquid, there is no particular need to provide a circulation pump, and the configuration other than the pump is the first one.
It can be exactly the same as the case shown in the figure.

FIG. 3 shows the case where the anode roller 6,6' is installed in the electrolytic cell. In this case, the power supply tanks J and 3' are separated, which simplifies the device, but there is a concern that current will leak from the anode roller to the cathode and reduce power efficiency, so it is better to install the power supply tank and the electrolytic tank separately. is preferred. The mode is illustrated in FIG. 1 and FIG. 1, but there are other ways to directly conduct a substantial amount of current between the anode roller and the cathode by vertically and/or horizontally three-dimensional positions or by appropriately shaped partition walls, etc. It is sufficient if the two can be isolated to such an extent that such a problem does not occur, and various embodiments can be adopted as such a specific method.

Furthermore, even when the feeding zone and the electrolytic zone are not in communication as shown in FIG. 1, it is convenient and preferable that the liquid in the feeding zone is the same as the electrolyte solution in the electrolytic zone, but it is not necessarily limited to this. The different electrolyte aqueous solutions and water sources may be liquids such as alcohol.

Carbon fiber tow S includes guide roller lI, anode roll, h
' and guide roller q' in this order and move to the right in FIG. Current is supplied to the carbon fibers through the anode rows 26 and A', so that the carbon fiber tow 5 between the anode rollers 6 and 6' is essentially an anode with respect to the cathode plate;
i! Undergoes deoxidation and oxidation.

8g41 illustrates a conventional processing apparatus for comparison with the present invention, in which an anode roller 6.6' is provided in the gas phase, and a guide roller 4.6' is provided in the gas phase. This device differs from the device used in the present invention in that Q' is provided at a position where it is immersed in the electrolyte.

The case where a roller is used as an anode has been described above, but a bar made of graphite can be used as an anode in addition to the roller.

Further, the carbon fiber tow used in the present invention is not particularly limited, and the pitch carbon fiber (b) may be a tow made by bundling known carbon fibers such as polyacrylonitrile carbon fiber. Bye. Note that the number of convergent fibers constituting the tow can be arbitrarily selected as appropriate.

(Effects of the Invention) As explained above, in the present invention, power is supplied by bringing the anode and the carbon fiber tow into contact during the 'tkL'M yarn bath sale, so there is no single yarn as the power is being supplied. ) Electric power is evenly supplied to each single yarn of the carbon fiber tow. Further, since the electrolyte solution is present in the contact area between the anode and the tow, the carbon fibers do not generate heat locally in the core, and therefore are not oxidized and deteriorated (strength reduced) by heating.

Furthermore, since the electrical resistance at the contact portion is small, there is also the advantage that the required voltage is low.

These advantages are further enhanced when the roller 8 is used as the positive roller.

Hereinafter, the present invention will be specifically explained with reference to Examples, but the gist and limitations of the present invention are not limited to the following Examples.

Example/ Yarn diameter obtained by firing pitch 1Rtr# at 00℃? , jμ of carbon steel, and 600 tows of ftp are used in the following row r drive using the device shown in Fig. 1 (Material of anode roll and cathode plate: graphite, length/shoulder) The surface was continuously treated with

', asi: wt% sulfuric acid aqueous solution supply'I! Hinoki solution: jwt% sulfuric acid aqueous solution Voltage: ! r,
tV current: 0. ! r A Yarn speed: sm 1 minute After the obtained carbon fiber tow was washed with water, the water was removed.

Immediately apply regular sizing agent and dry.

The strand strength and interlaminar shear strength of the nine carbon fibers obtained were measured according to Jxs-x-tbo/K, and the results were
Shown in the table.

Comparative Example/Exactly the same as Example/, except that the electrolytic cell in Example/ was changed to the device shown in FIG. Carbon fibers were surface treated in the same manner. The strand strength and interlaminar shear strength of the obtained carbon fibers were measured in the same manner as in Example 1,
The results are also listed in Table 1.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view of one example of the device used in the present invention, Fig. 1 is a schematic sectional view of another example, Fig. 3 is a schematic sectional view of still another example, and Fig. 4 is a conventional device. FIG. /: Electrolytic tank Koni cathode plate J: Power supply tank 6: Anode roller! = carbon fiber

Claims (3)

[Claims] (1) In a method in which a carbon fiber tow is immersed in an electrolyte solution and the surface of the carbon fiber is treated by electrolysis using the carbon fiber as an anode, the carbon fiber tow is stretched over an anode placed in the liquid. 1. A method for surface electrolytic treatment of carbon fiber tow, characterized in that a current is supplied to the carbon fiber tow through the anode by bringing the carbon fiber tow into contact with the carbon fiber tow. (2) The method according to claim 1, wherein the anode is a roller. (3) Separately providing a zone for supplying current to the carbon fiber tow via the anode and a zone for electrolyzing the carbon fiber tow and surface-treating each carbon fiber constituting the carbon fiber tow. A method according to claim 1, characterized in that: