JPS62282025A - Production of pitch carbon yarn - Google Patents

Abstract

PURPOSE:To obtain high-quality tow stably without causing end breakage, wrapping, etc., by bundling pitch yarn spun from a great number of nozzles by two or more specific guide mechanisms. CONSTITUTION:In forming tow by bundling a pitch yarn group 3 spun from a great number of nozzles of a spinning head 1, the pitch yarn group after spinning is treated by using two or more guides. A fixed type guide which will not rotate is used as a first guide 7 and a rotary roller having low resistance is used a second guide 9.

Description

DETAILED DESCRIPTION OF THE INVENTION Detailed Description of the Invention The present invention relates to a method for producing carbon fiber using a pitch-based material.

Pitch-based carbonized fibers obtained by spinning, infusible, carbonizing, and/or graphitizing pitch-based materials are organic synthetic fibers such as polyacrylonitrile (, PA, N). Compared to carbon fiber that uses carbon fiber as a precursor, it is a cheaper and higher-performance material because the raw material is cheaper and the yield during carbonization is lower, so the manufacturing cost is lower, and it is easier to produce with a high modulus of elasticity. It is expected that this will become possible. However, one of the manufacturing problems with pitch-based and carbon fibers is that the precursor (pitch fiber) obtained from pitch-based materials is weaker than organic synthetic fibers such as PA and N. In the conventional method used for spinning organic synthetic fibers, when spinning and bundling H:Tutsi fibers, thread breakage that causes fuzz occurs, and winding around the ends and ends of the fibers occurs. It is difficult to stably and continuously spin pitch fibers with few defects due to their low aggregation properties.The carbon fibers obtained without fully solving these problems are ,
Naturally, quality stability is poor in terms of physical properties, fluffiness, etc., and the yield during spinning is poor, resulting in higher production costs.

Means for Solving the Problems As a result of extensive research in view of the current state of the prior art as described above, the present inventor has developed a method that uses at least two kite mechanisms in the process of converging pitch fibers and making tows. However, if the first guide mechanism is configured with a fixed kite or air sucker that does not rotate, and the second kite mechanism is configured with a rotating roller with low rotational resistance, the problems of the prior art can be greatly alleviated. I found out what I got. Furthermore, it has also been found that even better results are obtained if the pinched fibers are provided with a sizing agent before reaching the first kite mechanism. That is, the present invention provides the following method: ■ A method for producing carbon fiber by spinning a pinch material using a multi-hole nozzle, making it infusible, and carbonizing and/or graphitizing it. When converging pitch fibers to form a tow, two or more kite mechanisms are used, the first kite mechanism being a fixed kite or air sucker that does not rotate, and the second guide mechanism being configured with a rotational resistance. A method for producing pitch-based carbon fiber, characterized by comprising using small rotating rollers.

(2) The method for producing pitch-based carbon fibers according to (2) above, wherein a sizing agent is applied to the pinched fibers between the nozzle surface and the first kite mechanism.

The spinning pitch system vJiFl used in the present invention is preferably obtained by thermal polycondensation of a pitch-like substance while flowing an inert gas. The pitch-like substance may be any of petroleum-based pitch, coal-based pinch, and pyrolysis residue pitch from organic compounds.

Two or more guide mechanisms are required for use in the method of the present invention, except for traverse skies or air suckers for bobbin winding or can picking, and pitch fibers cannot be focused well with one guide mechanism.

The first of the two or more guide mechanisms for focusing the pitch fibers must be a fixed, non-rotating guide or air sucker. If the first guide mechanism is a rotating kite, such as a free roller with low rotational resistance, the pinched fibers will often break, causing the broken threads to wrap around the rotating rollers, making it difficult to continue spinning. It becomes impossible. The material and shape of the fixed guide are not particularly limited as long as they have a hard and smooth surface and low electrical resistance and contact resistance. Examples of the material include aluminum plated with hard chrome, and rigid resin that provides conductivity. As for the air sucker, it only needs to be able to send air evenly and have a smooth curved inner surface, and can be made of the same material as the fixed guide. The second guide mechanism must be constructed of a rotating roller with low rotational resistance. When the second guide mechanism is a fixed kite, thread breakage that causes fluff occurs frequently. The material of the rotating roller may be the same as that of the first guide mechanism.

Pitch fibers have lower elongation and strength than general organic synthetic fibers and are brittle, so it is better that pitch fibers do not come into contact with other mechanisms as much as possible during spinning and convergence. Therefore, if possible, it is preferable to use a spinning/focusing mechanism that is composed of the above-mentioned first and second guide mechanisms and a traverse guide or air sucker for bobbin winding or dancing.

If a sizing agent is used, it is necessary to apply at least a portion of it to the pinched fibers between the nozzle face and the first guide mechanism. If the sizing agent is applied only after the pitch m,* has passed through the first guide mechanism, no improvement in the effect of using the sizing agent can be observed.

When only a portion of the sizing agent is applied between the nozzle surface and the first guide mechanism, the remainder of the sizing agent is applied between the first and second guide mechanisms and between the second guide mechanism. It can be applied at any position, such as between the mechanism and the traverse guide or air sucker for bobbin winding or dancing.

As the sizing agent, known ones can be used, such as water, silicone oil, ethylene oxide adducts of higher alcohols, and aqueous dispersions of silicone oils, ethylene oxide adducts of higher alcohols, and the like.

FIG. 1 shows an outline of one embodiment of the method of the present invention.

The pitch fiber (3) obtained by the spinning device (1) equipped with a multi-hole nozzle passes through the spinning tube (5) and comes into contact with the fixed kite (7) as a first guide mechanism, and then passes through the second It comes into contact with a free roller (9) as a guide mechanism.

The pitch fibers are then redirected by a free roller (11) and wound onto a driven bobbin (15) through a traverse guide (13) or by using a godet roller instead of the bobbin (15). Dance is taken. If a sizing agent is used, at least a portion of it is distributed between the spinning device (1) and the fixed guide (7), preferably between the spinning device (1) and the spinning tube (5) to pinch the fibers (3). Spray on.

Effects of the Invention According to the present invention, when spinning and converging pitch fibers,
A pitch fiber tow with good cohesiveness can be obtained without causing thread breakage or winding around a roller, which causes fuzzing of the final carbon fiber, and carbon fiber with excellent quality stability can be efficiently produced.

EXAMPLES Below, Examples and Comparative Examples will be shown to further clarify the characteristics of the present invention.

Example 1 A mixed solution of 1 part by weight of coal tar pitch and 2 parts by weight of hydrogenated anthracene oil having a softening point of 110'C, a quinoline-soluble content of 0.18% by weight, and a benzene-insoluble content of 35% by weight was heated to 430' in an autoclave. After heating with stirring for 60 minutes at
The hydrogenated anthracene oil was removed at °C to obtain reduced pitch.

Put the reduced pitch 50KFI obtained above into a reactor equipped with a gas introduction pipe, a thermocouple, a stirrer and a distillate removal pipe,
Removal of low molecular weight components and thermal polycondensation were carried out at 410 to 480° C. for 4 hours while stirring and introducing nitrogen gas.

The physical properties of the obtained pitch were as follows: a softening point of 315°C (according to a softening point measuring device manufactured by Mettler, Switzerland), a quinoline solubility of 3
Using the obtained heat-treated pitch having an optically anisotropic component of 98° and 5% by volume, the filament was spun from a nozzle head with 300 nozzle holes at a spinning temperature of 340°C and a spinning speed of 350 m/min. Melt spinning was performed under conditions of a diameter of 11 μm. 300 filaments are sprayed with water before reaching the fixed guide as the first guide mechanism;
After converging by the first fixed cast and passing through a rotating roller type guide as a second guide mechanism, the fibers were subsequently passed through a guide roller and wound up to obtain a tow of pitch fibers. Note that water was also sprayed onto the first and second guide mechanisms. There was no yarn breakage at the guide portion during spinning, and stable continuous spinning was possible.

The pitch fiber obtained as described above was heated to 200 to 3
Infusibility treatment was carried out at 20'C for 30 minutes, and further in nitrogen gas for 12 minutes.
Carbon fibers were obtained by holding at 00'C for 3 minutes. The carbon fibers had a tensile strength of 275 K9/#2, and were continuous fibers with no fuzz and stable quality.

Comparative Examples 1 to 3 The first and second guide mechanisms were each of rotating roller type.
Pitch fiber tows were obtained in the same manner as in Example 1, except for using a rotating roller type (Comparative Example 1), a rotating roller type-fixed guide (Comparative Example 2), and a fixed guide-fixed kite (Comparative Example 3). . In either case, stable continuous spinning was difficult due to filament breakage and roller wrapping. Further, the carbon fiber obtained by infusibility and firing in the same manner as in Example 1 had a lot of fuzz and lacked quality stability.

[Brief explanation of the drawing]

FIG. 1 shows an example of an embodiment of the present invention. (1) ... spinning device, (3)...Pitch fiber, (5) ... spinning tube, (7)...Fixed guide, (9)...free roller, (here)...free roller, (13)...traverse skite, (15>... Drive bobbin. (that's all) 1st 11＼〜 Up ゝ＼－１ N5 ~3 ・　7 ・　9 ．． 11

Claims (2)

[Claims] (1) Spinning pitch-based material using a multi-hole nozzle,
In a method of producing carbon fiber by infusible carbonization and/or graphitization, two or more guide mechanisms are used and the first guide mechanism is rotated when converging spun pitch fibers to form a tow. 1. A method for producing pitch-based carbon fiber, characterized in that the second guide mechanism is a rotating roller with low rotational resistance. (2) The method for producing pitch-based carbon fibers according to claim 1, wherein a sizing agent is sprayed onto the pitch fibers between the nozzle surface and the first guide mechanism.