JPS61124645A - Opening of carbonaceous fiber - 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 Field of Application) The invention relates to a method for defibrating carbon fiber tow, particularly carbon fiber tow.

(Prior art) Carbon fiber is used as a composite material with various matrices, for example, by impregnating it with a matrix resin such as epoxy resin, polyamide resin, or phenol resin (prepreg) and molding it using various molding methods. Fiber-reinforced plastics are used for leisure and sports purposes such as fishing rods, golf shafts, and ski boards, and as industrial materials such as leaf springs, springs, and gears.

Carbon fibers used in this way are made by heating synthetic fiber tow such as polyacrylonitrile fiber in an oxidizing atmosphere such as air to make it flame resistant, or by melt-spinning coal-based or petroleum-based pitch. The obtained pitch fiber tow is
7. Heat in an oxidizing atmosphere to make it infusible, such as air, 1:. Further heat it in a high-temperature inert gas atmosphere and subject it to carbon coating or graphitization. Manufactured □;”

However, fiber tow that has been made flameproof or infusible (hereinafter simply referred to as infusible fiber tow), and fiber tow that has been carbonized or graphitized (hereinafter referred to as single carbon fiber tow)
The fiber tow lacks flexibility due to the lubricant used in the previous process or the thermal alteration of the fiber itself in each process, or the fibers are fused together, resulting in uneven quality. Non-uniform dispersion of single filaments in the resin may impair the homogeneity of the composite material, so the process of making it flame resistant, infusible, carbonizing or graphitizing makes it flexible and fused. No state of busy defibration. Conventionally, methods for defibrating infusible fiber tow or carbon fiber tow include a method in which the fiber tow is subjected to turbulence treatment, a bending treatment method in which the fiber tow is passed through a guide button such as a bar, wire, or rotating bottle while being bent in a zigzag manner, and a convex shape A method of making contact with the curved surface of a roll having a curved surface (Japanese Patent Application Laid-Open No. 6701j) and a method of defibrating in a fluid (Japanese Patent Application Laid-open No. 2-9631) have been proposed.

(Problems to be solved by the invention) However, all conventional methods lack flexibility;
Alternatively, K is still insufficient for defibrating infusible fiber tow or carbon fiber tow in which fibers are fused together.

(Means for Solving the Problems) Therefore, the present inventors have discovered that the fiber tow lacks flexibility, or that the fibers are fused to each other and that the infusible fiber tow is in a virtual state.
As a result of extensive research into a method for defibrating carbon fiber tows into a pliable, MiII-free state with simple operations and without producing fluff, we developed a tapered roller with alternating fiber tows. It has been found that this purpose can be easily achieved by bringing the KiM into contact with the inclined M+ surface of the KiM, and based on this knowledge, the present invention has been completed.

That is, the gist of the present invention resides in a method for defibrating carbonaceous fibers, which is characterized in that the fibers are brought into contact with the slope of the toe of the carbonaceous transverse cord.

The present invention will be described in detail below, and the carbonaceous memory fiber tow used in the present invention includes polyacrylonitrile fibers, polyacrylonitrile fibers,
Flame-resistant, carbonized or graphitized fibers such as cellulose fibers and polyvinyl alcohol fibers;
Alternatively, it is a pitch-based fiber tow treated to be infusible, carbonized, or graphitized.

In particular, in the case of pitch-based fiber tow, as the heat treatment progresses from infusibility to carbonization to graphitization, the tow tends to lack flexibility, or the MS of the fibers tends to become stronger. It is also possible to once fibrillate at the stage of infusible fiber tow and further defibrate at the stage of carbon fiber tow.

The number of single yarns forming a tow is not particularly limited, but is usually 3.
00-3oo, ooo books, preferably j00-10,0
θ0 pieces are used.

The tapered roller used in the present invention is a roller having a tilted side surface, specifically a conical roller 2 as shown in FIG. The angle α with the roller center axis is 3 to 50
degrees, preferably! It has an inclined surface 6 of ~30 degrees. If the angle α is less than 3 degrees, defibration cannot be performed sufficiently, and if the angle α is less than 3 degrees,
If the degree is exceeded, the fiber tow may be biased towards the smaller diameter side or the tow may be excessively bent between the rollers, making it difficult to perform a smooth defibration operation. The size is appropriately selected depending on the number of carbon fiber tows, the number of tows to be defibrated, the degree of defibration, etc., but usually the diameter of the large diameter portion is dO,!
-j tel, length L/~! A secondary one is used, and as shown in FIG.
It is preferable for the defibration operation to be provided.

In the present invention, it is necessary to arrange the tapered rollers as described above so that the directions of inclination of the inclined surfaces of the rollers are substantially alternating. "To install a tapered roller" means to arrange the tapered roller so that the small diameter part and the large diameter part are located opposite to each other, but as long as it does not cause any inconvenience to the defibration operation, a large number of taper rollers can be installed. This also includes cases where the alternating regularity is partially disturbed, such as when some of the rollers are in the same direction or there is a neutral roller in the middle.

The size, number, and arrangement of the taper rollers are appropriately selected depending mainly on the degree of pliability of the carbon fiber tow and the degree of fusion of the fibers. The number of tapered rollers is usually 2 to 70 θ, preferably 2 to 70 θ, and more preferably 6 to 0, but tapered rollers of different sizes are used. It is also possible to use appropriate combinations of the molecules.

The roller placement is direct &! A shape, an S shape, a W shape, an arc shape, or a combination of these can be used.

The case of the linear type will be explained with reference to FIGS. 1 and 2.

FIG. 1 is a plan view of an example of the linear type, and FIG. 2 is a front view of the same. Tapered rollers are roller support frames! The inclined surfaces 6 are rotatably inserted into a central axis provided in a straight line.

In figure 0! i) Also, as shown in FIG. 2, the distance LFi between the center axes 9 of the rollers λ is usually set to θ, j−j (7), although it depends on the angle α of the roller surface and the size of the rollers. The carbon fiber tow 3 passes alternately over and below the inclined surface B of the adjacent tapered roller from the guide roller, and is stretched between the guide rollers on the opposite side.

Then, by rotating a winding bobbin (not shown), the carbon fiber tow 3 is pulled in the direction of the arrow, so that the inclined surfaces of which the inclined directions are alternate are brought into contact with each other, and the carbon fiber tow 3 is pulled in the direction of the arrow. A force that causes the carbon fiber tow to shift laterally with respect to the direction in which the tow travels is applied alternately. In other words, the fibers are subjected to a squeezing operation that separates the fusions between the fibers.

In the case of the S type, the tapered rollers are arranged in a figure 8 shape as shown in FIG.

The carbon fiber tow 3 is stretched so as to come into contact with the outside of a tapered roller arranged in an S-shape, and is pulled in the direction of the arrow ((a) in FIG. 5). In addition, as a method of stretching the carbonaceous W fiber tow, there is also a method of stretching the inside and outside of the tapered roller alternately ((b) in Figure 5), or a method of stretching the outside of the tapered roller twice and the inside. Various methods can be adopted, such as a method of stretching seven pieces in order ((c) in FIG. 5).

In the case of the W type, tapered rollers are arranged in two rows as shown in FIG. The carbon fiber tow is stretched between the taper rollers of the 3Fiλ rows in a W-shape and pulled in the direction of the arrow.

In the case of an arc type, taper roller/
are arranged in an arc shape, or as shown in the figure, a tapered loaf is arranged in an arc shape on a rotary plate. The carbon fiber tow 3 is stretched so as to contact the outside of a tapered roller arranged in an arc shape, and is pulled in the direction of the arrow (
(a) in Figure 7). In addition, in the case of the arc type, similar to the Japanese character type, the same method of stretching (for example, the 7th Shino (B), (C)) is applied.
may be done.

The defibration operation can also be carried out in the gas phase, but water or water-soluble substances such as surfactants consisting of anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants or mixtures thereof may be used. If the process is carried out in an aqueous solution such as alcohol, and/or after the carbon fiber tow is moistened with water or an aqueous solution of the above-mentioned easily water-soluble substance, there will be less fuzz and the defibration operation can be carried out smoothly. preferable. The concentration of the easily water-soluble substance varies depending on the substance, but in the case of surfactants, it is best to set it to 0°θ/~t wt%, and if the substance remains in the fiber after tIfIR, it is a problem. After defibration, the material may be removed by washing with water.

Furthermore, acids such as sulfuric acid and nitric acid,
Alkali such as caustic soda and caustic potash, or salts such as sodium chloride and sodium chloride can also be used.

Then, the carbon fiber tow defibrated using an aqueous solution of these substances can be subsequently subjected to surface treatment operations such as wet oxidation and electric M oxidation using an aqueous solution of these substances.

(Effects of the Invention) As detailed above, the present invention brings a carbon fiber tow into contact with the inclined surfaces of at least two tapered rollers arranged so that the inclined directions of the inclined surfaces are alternate. It is an extremely excellent method for defibrating carbonaceous fibers because it can easily defibrate partially fused fibers into a flexible state, even though they lack flexibility. .

(Examples) Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following 9 Examples as long as the gist thereof is not exceeded.

Example/ A device equipped with a large diameter ('')/, length μ) 2' on, inclination angle (α) 73 degrees, and distance between the roller center axes CL) 2' on is approximately 0./ It was placed in a water tank containing an aqueous solution of a wt.

A carbon fiber tow with a diameter of 10 μm and a number of 3θ00 single fibers obtained by melt-spinning, infusible, and carbonizing coal-based pitch was stretched as shown in FIG. The defibrated tow that came out was washed with water, wound up at a speed of about 2ff1/cm, and then dried.

□゛・ The thus obtained W1 tow is flexible and does not cause the fibers to fuse together, and is impregnated into the epoxy resin of the matrix, and after hardening, it can be applied in the longitudinal direction of the tow.
f, b-work, ya□6. . 5o air□□yo1,1
As shown in Fig. 2, the single yarn 10 is made of epoxy resin/
/ and showed excellent homogeneity.

On the contrary, the tow of the carbon-seed string before being woven lacks flexibility, and there is a lot of molten liquid among the fibers. is wrinkled and dispersed unevenly in the epoxy resin, resulting in a homogeneity of 9'1
It was on.

Example 1 The procedure of Example 1 was repeated except that the carbonaceous fiber tow was an infusible fiber tow to obtain a frozen tow, which was further carbonized to obtain a carbon fiber tow.

The tow is flexible and the fibers do not fuse together, and when the cross section is observed in the same manner as in Example, the single yarns are uniformly dispersed.
It was homogeneous.

[Brief explanation of the drawing]

Fig. s1 is a plan view of an example of the device used in the present invention, Fig. Mλ is a front view of the same, Figs. The figure is an explanatory view showing another example of the arrangement of the tapered roller, and the figures 1 to 2 are schematic views showing the state of dispersion of fibers in the epoxy resin. /: Tapered roller −: Guide roller 3: Carbon fiber tow 6: Tapered roller inclined surface Applicant: Mitsubishi Chemical Industries, Ltd. Agent Patent attorney For Hase − (and 7 others) Figure 1 Collection Figure 2 3f21 Figure 4 Figure 5 (W) (C)

Claims (7)

[Claims] (1) Carbonaceous fiber characterized in that the tow of the carbonaceous fiber is brought into contact with the inclined surfaces of at least two tapered rollers arranged so that the inclined directions of the inclined surfaces are substantially alternate. defibration method. (2) The method according to claim 1, characterized in that the carbon fiber tow is wetted with water and brought into contact with the inclined surface of the tapered roller. (3) The method according to claim 1, characterized in that the carbon fiber tow is brought into contact with the inclined surface of a tapered roller underwater. (4) The method according to any one of claims 1 to 3, wherein the angle of the inclined surface of the tapered roller is 3 to 50 degrees with respect to the central axis of the roller. (5) Claims 1 to 3, characterized in that the carbonaceous fibers are pitch-based fibers, polyacrylonitrile-based fibers, cellulose-based fibers, or polyvinyl alcohol-based fibers made infusible or flame-resistant. The method described in any of the paragraphs. (6) The carbonaceous fiber is characterized by being carbonized and/or graphitized after making pitch-based fiber, polyacrylonitrile-based fiber, cellulose-based fiber, or polyvinyl alcohol-based fiber infusible or flame-resistant. A method according to any one of claims 1 to 3. (7) The method according to claim 2 or 3, wherein the water contains a surfactant or an alcohol.