JP4459398B2 - Method for producing wound body of carbon fiber precursor fiber bundle - Google Patents

Description

【００２９】
比較例１では、前駆体繊維束に収束性を付与せずに、２本の繊維束を巻取体に巻き取っているため、耐炎化及び炭素化の際に引き揃えれられたときに、各繊維束の単繊維同士が絡み合ってしまい、炭素化後に元の各繊維束に分割する際に毛羽が発生してしまう。
【００３０】
また、比較例２では、前駆体繊維束に空気交絡処理により収束性を付与する際のエアー処理圧力が大きいため、この空気交絡処理により、前駆体繊維束に毛羽が発生してしまう。
【００３１】
更に、比較例３では、適度に収束性が付与されている２本の繊維束を、Ｖ型溝を通過させて１本の糸条に合糸してからボビンに巻き取っているため、その巻取時に単繊維同士が交絡し、以降、各繊維束に分割する際の分割性が悪く、分割時に毛羽が発生する。
【００３２】
以上、説明したように、本発明によれば、フィラメント数の少ない炭素繊維前駆体繊維束を焼成する際に、複数の前駆体繊維束を引き揃えることなく単一のボビンに巻き取られた巻取体を採用することにより、前記巻取体から引き出した複数の繊維束を１本に引き揃え、従来、単一の繊維束を走行させていた部位に安定して走行させ、焼成することができるため、焼成装置内での繊維密度が高まり、焼成工程での生産性を向上させ、フィラメント数の多い場合と同様の生産性を得ることが可能となる。
【００３３】
また、複数の前駆体繊維束を引き揃えることなく単一の巻取体に巻き取っているため、各繊維束の独立性が高く、同巻取体から複数の繊維束を同時に引き出して、一本の糸条として引き揃えて焼成工程を経た後に再度、前記糸条から複数の繊維束に分割する際にも、容易に分割される。そのため、毛羽の発生も少なく、高品質の炭素繊維束を得ることができる。
【００３４】
また、巻取体に巻き取る際に複数の繊維束を合糸するための工程が不要となるため、その設備も排除でき、更には、分割性が良好であるため、各繊維束を加撚する必要もなく、この加撚の設備とそれに伴う解撚の設備とを排除でき、設備費低減に寄与できる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a wound body of carbon fiber precursor fiber bundles. More specifically, the present invention relates to a method for producing a wound body of carbon fiber precursor fiber bundles suitable for efficiently producing a carbon fiber bundle having a small number of filaments.
[0002]
[Prior art]
Carbon fibers are widely used as a reinforcing fiber for composite materials in aerospace applications, sports applications, general industrial applications, and the like.
[0003]
Carbon fiber is converted to oxidized fiber by heating the precursor fiber in a spinning process of spinning polyacrylonitrile fiber, which is the precursor fiber, in an oxidizing atmosphere such as air and nitrogen oxide at 200-300 ° C. And a carbonization step of heating to 300 to 3000 ° C. in an inert atmosphere such as nitrogen, argon or helium.
[0004]
In general, in the firing process such as the flameproofing process and the carbonization process, the processing takes a long time, so the traveling speed of the fiber bundle is slower than that in the spinning process. Therefore, when manufacturing carbon fiber with high efficiency, among the above-described manufacturing steps, the firing step tends to be rate-limiting. Therefore, in order to efficiently produce a carbon fiber bundle having a small number of filaments, it is desirable to increase the ratio of the fiber bundle to the space in each processing apparatus in the firing process (hereinafter referred to as the fiber bundle density in the apparatus). . That is, it is necessary to increase the number of fiber bundles that can be run in one manufacturing facility.
[0005]
However, if an attempt is made to increase the number of fiber bundles to be run in a single production facility, it is necessary to increase the installation equipment in the firing process and the take-up equipment for the carbon fiber bundle as the number of fiber bundles increases. Yes, the capital investment cost increases.
[0006]
Therefore, in order to efficiently produce a carbon fiber bundle with a small number of filaments without adding additional equipment for the precursor fiber bundle firing step, conventionally, a plurality of fiber bundles are combined to form a thick yarn. In the conventional firing apparatus such as flameproofing or carbonization, a thick yarn obtained by joining a plurality of fiber bundles is made to run in a part where a single fiber bundle is made to run.
[0007]
These thick yarns are divided into original fiber bundles after becoming a carbon fiber through a firing step. For example, in the carbon fiber manufacturing method disclosed in Japanese Patent Application Laid-Open No. 9-273032, in order to facilitate subsequent division, each fiber bundle is provided with a V-shaped or U-shaped groove when spinning the precursor fiber bundle. After passing the guide, or twisting sweetly or applying gas entanglement treatment to give convergence, pass multiple fiber bundles with such convergence through V-shaped or U-shaped grooved guides After being combined, they are wound up.
[0008]
[Problems to be solved by the invention]
However, in the method described in the above publication, the splitting ability is improved, but more than one fiber bundle is wound on a single yarn and wound, so that the single fibers are wound together at the time of winding. After that, it is unavoidable that the splitting property at the time of splitting into each fiber bundle deteriorates, and fluff is generated at the time of splitting into each fiber bundle and the quality of the carbon fiber bundle is lowered.
[0009]
Therefore, in order to improve the splitting property from the yarn into a plurality of fiber bundles, twisting may be performed in the spinning process in order to improve the convergence of each fiber bundle. However, in that case, the fiber bundle must be untwisted in the firing step, which necessitates equipment costs and is not preferable.
[0010]
The present invention aims to eliminate the above-described conventional problems, and specifically, in the production of carbon fibers by firing a precursor fiber bundle, while suppressing new equipment investment, in the firing step A carbon fiber precursor fiber bundle wound body that can increase the density of the fiber bundle in the apparatus, produce a carbon fiber bundle with a small number of filaments with high efficiency, and obtain a high-quality carbon fiber bundle with extremely low fluff generation; It aims at providing the manufacturing method of the winding body.
[0011]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the invention according to claim 1 of the present invention does not align each fiber bundle after imparting convergence to each of at least two carbon fiber precursor fiber bundles by gas entanglement treatment. It is characterized by being wound on a single bobbin while traversing independently and synchronously .
[0013]
A plurality of fiber bundles are simultaneously drawn out from a wound body in which the single carbon fiber precursor fiber bundle is wound, and these are bundled together and introduced into a conventional flameproofing and carbonizing apparatus. Then, the part where the single fiber bundle was made to travel is made flameproof and carbonized. Thereby, the fiber bundle density in a flameproofing and carbonization apparatus increases, and the manufacturing efficiency of carbon fiber increases. Moreover, since an existing apparatus can be adopted as the apparatus, no new equipment cost is required.
[0014]
A plurality of fiber bundles that are aligned and carbonized are divided into original fiber bundles after carbonization. At this time, according to the present invention, it is not necessary to arrange a plurality of fiber bundles at the stage of the winding body, and individual independent fiber bundles are wound together on a single bobbin, so that flame resistance is achieved. In addition, since only a plurality of fiber bundles are aligned in one during carbonization, each fiber bundle can be divided very easily when dividing after carbonization. Therefore, generation | occurrence | production of fluff can also be prevented and the carbon fiber of the outstanding quality can be obtained.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be specifically described.
As the precursor fiber bundle in the present invention, an acrylic fiber bundle made of an acrylic polymer composed of 90% by weight or more of acrylonitrile can be used. If it is within 10% by weight, a monomer other than acrylonitrile may be included as a copolymerization component.
[0016]
Examples of the copolymerization monomer include acrylic acid, methacrylic acid, itaconic acid, or methyl ester, ethyl ester, propyl ester, butyl ester, alkali metal salt, ammonium salt, or allyl sulfonic acid, methallyl sulfonic acid, styrene sulfone. An acid or an alkali metal salt thereof, styrene, vinyl acetate, acrylamide or the like can be used.
[0017]
The precursor fiber bundle can be manufactured as follows. The acrylic polymer is polymerized using a polymerization method such as emulsion polymerization, bulk polymerization, solution polymerization and the like, and when producing acrylic fibers from these polymers, dimethylacetamide, dimethyl sulfoxide, dimethylformamide, nitric acid, rhodium soda aqueous solution Then, a polymer solution using a zinc chloride aqueous solution or the like as a solvent is used as a spinning stock solution to be fiberized by wet spinning or dry wet spinning.
[0018]
The spun fiber bundle is usually stretched in a bath. The stretching in the bath may be performed directly on the spun fiber bundle, or the spun fiber bundle may be washed once with water to remove the solvent and then stretched in the bath. In the stretching in the bath, the stretching is usually performed about 2 to 6 times in a stretching bath at 50 to 98 ° C. The fiber bundle after stretching in the bath is usually provided with an oil agent, dried and densified with a hot roller, etc., and then stretched about 2 to 6 times in steam to obtain an acrylic fiber bundle, thereby imparting convergence. Is done.
[0019]
Examples of means for imparting convergence include means for entanglement of single fibers constituting the fiber bundle such as gas entanglement treatment and needle punch treatment, and means by false twisting, etc., from the viewpoint of suppressing the occurrence of fluff. Is most preferably focused by gas entanglement.
[0020]
When the fiber bundle is converged by gas entanglement, the gas pressure supplied to the gas entanglement processing apparatus is preferably 80 to 650 kPa, more preferably 150 to 550 kPa. If the gas pressure is 80 kPa or less, sufficient convergence cannot be imparted by gas entanglement, and if it is 650 kPa or more, the gas pressure is too high and damages the fiber bundle, causing fluffing of the carbon fiber precursor fiber bundle.
[0021]
A plurality of fiber bundles imparted with convergence are wound around a single bobbin without being aligned by a winder or the like to obtain a wound body of carbon fiber precursor fiber bundles. From the viewpoint of ease of splitting into a plurality of fiber bundles later, and from the viewpoint of equipment restrictions, the number of filaments in the fiber bundle is preferably 500-12000 filaments, more preferably 1000-8000 filaments, The number of fiber bundles wound around the bobbin as a collecting body is preferably 2 to 10, more preferably 2 to 6.
[0022]
Hereinafter, the present invention will be described with reference to specific examples.
In the following examples, the number of fluff when the obtained carbon fiber bundle was divided into a plurality of fiber bundles was determined by observing the fiber bundle immediately after division in the running state with the naked eye for 1 hour. It was determined by measuring the number.
[0023]
Further, in the examples, the number of fluffs of the precursor fiber bundles was determined by observing the precursor fiber fiber bundles that were pulled out of the winding body in the firing apparatus and in the running state with the naked eye for 1 hour. It was determined by measuring the number.
[0024]
(Comparative Example 1)
A dimethylacetamide solution of an acrylic polymer was used as a spinning stock solution and discharged into a coagulation bath composed of dimethylacetamide and water using a 3000 hole die to obtain a coagulated fiber bundle. After the coagulated fiber bundle is washed with water, it is stretched 5 times in hot water to give an oil agent, followed by drying and densification, followed by drying through a pressure steam stretching process, and the single fiber fineness is 1. A drawn fiber bundle having a total fineness of 3000 d at 0 d was obtained.
The two drawn fiber bundles were wound around a single bobbin with a winder while being traversed independently and synchronously without being aligned, thereby producing a wound body of precursor fiber bundles.
Next, a plurality of fiber bundles were pulled out from the wound body at the same time and aligned into one, led to a firing step, subjected to flame resistance treatment, and subsequently carbonized. After the carbonization treatment, a plurality of fiber bundles aligned into one were divided into original fiber bundles to obtain carbon fiber bundles having 3000 filaments. Table 1 shows the number of fluffs and the number of fluffs of the precursor fiber bundle at the time of the division.
[0025]
Example 1
After converging the stretched fiber bundles using an air entanglement processor, the two fiber bundles are traversed independently and synchronously without being aligned, and a single bobbin is wound with a winder. Winded up.
Thereafter, as in Comparative Example 1, a plurality of fiber bundles are drawn from the winding body at the same time and aligned to one, subjected to flame resistance and carbonization treatment, and then aligned to one. Was divided into original fiber bundles to obtain a carbon fiber bundle having 3000 filaments. Table 1 shows the number of fluffs when the fiber bundles are divided and the number of fluffs of the precursor fiber bundles.
In addition, the entanglement process was performed with the air pressure of the air entanglement processing machine being 100, 200, 300, 500, 600 kPa.
[0026]
(Comparative Example 2)
A winder of the precursor fiber bundle was manufactured in the same manner as in Example 1 with the air pressure of the air entanglement processor used to impart convergence to the drawn fiber bundle being 700 kPa. Thereafter, in the same manner as in Example 1, a carbon fiber bundle having 3000 filaments was obtained. Table 1 shows the number of fluffs when the fiber bundles are divided and the number of fluffs of the precursor fiber bundles.
[0027]
(Comparative Example 3)
Two precursor fiber bundles, which are obtained by setting the air pressure of the air entanglement processing machine when imparting convergence to the drawn fiber bundle to 300 kPa, are passed through a V-shaped grooved guide, After being combined with the yarn, it was wound around a single bobbin to produce a wound body. Next, the yarn was pulled out from the wound body, subjected to flame resistance and carbonization treatment, and then divided into original fiber bundles to obtain a carbon fiber bundle having 3000 filaments. Table 1 shows the number of fluffs and the number of fluffs of the precursor fiber bundle in this division.
[0028]
[Table 1]

[0029]
In Comparative Example 1, since the two fiber bundles are wound around the winding body without imparting convergence to the precursor fiber bundle, each of the fiber bundles is aligned at the time of flame resistance and carbonization. Single fibers of the fiber bundle are entangled with each other, and fluff is generated when the fiber bundle is divided into original fiber bundles after carbonization.
[0030]
Further, in Comparative Example 2, since the air treatment pressure when the convergence property is imparted to the precursor fiber bundle by the air entanglement process, fluff is generated in the precursor fiber bundle due to the air entanglement process.
[0031]
Furthermore, in Comparative Example 3, since the two fiber bundles to which the convergence property is moderately imparted are passed through the V-shaped groove and combined with one yarn and wound around the bobbin, Single fibers are entangled at the time of winding, and after that, the splitability when splitting into each fiber bundle is poor, and fluff is generated during splitting.
[0032]
As described above, according to the present invention, when the carbon fiber precursor fiber bundle having a small number of filaments is fired, the winding wound around the single bobbin without aligning the plurality of precursor fiber bundles. By adopting a take-up body, a plurality of fiber bundles drawn from the take-up body are aligned to one, which can be stably run and fired in a portion where a single fiber bundle has been run conventionally. Therefore, the fiber density in the baking apparatus is increased, the productivity in the baking process is improved, and the same productivity as when the number of filaments is large can be obtained.
[0033]
In addition, since a plurality of precursor fiber bundles are wound around a single winding body without being aligned, each fiber bundle is highly independent, and a plurality of fiber bundles are simultaneously drawn out from the winding body. When the yarns are arranged as a book yarn and subjected to a firing process, the yarn is easily divided into a plurality of fiber bundles. Therefore, the generation of fluff is small and a high-quality carbon fiber bundle can be obtained.
[0034]
In addition, since a process for combining a plurality of fiber bundles when winding on a winding body becomes unnecessary, the equipment can be eliminated, and furthermore, the splitting property is good, so that each fiber bundle is twisted. Therefore, it is possible to eliminate the twisting equipment and the accompanying untwisting equipment, thereby contributing to a reduction in equipment costs.

Claims (1)

After imparting convergence by the gas entangling treatment to each of at least two carbon fiber precursor fiber bundle, each fiber bundle pulling align things ku independently and synchronously wound to a single bobbin while traversing A method for producing a carbon fiber precursor fiber bundle wound body.