JPS62156316A - Production of carbon fiber and graphite fiber - Google Patents

Abstract

PURPOSE:To efficiently obtain the titled fibers having good external appearance and high strength and elastic modulus without breaking of a fiber bundle in infusibilization, by doubling carbonaceous pitch fibers, applying a specific oiling agent and continuously infusibilizing the resultant fiber bundle in a linear state. CONSTITUTION:Carbonaceous pitch, preferably optically anisotropic pitch having 230-320 deg.C softening point is melt spun into pitch fibers, which are once wound onto, e.g. plural bobbins, and simultaneously unwound and doubled by winding onto one bobbin. In the process, an aqueous emulsion based heat-resistant oiling agent is applied to the doubled fibers at the same time. The resultant fiber bundle in a linear state is continuously passed through an oxidizing atmosphere, infusibilized and then carbonized or graphitized in an inert gas atmosphere to afford the aimed fibers. An oiling agent obtained by distilling a nonionic surfactant under reduced pressure and emulsifying an alkylphenylpolysiloxane having 100-1,000cst viscosity at 25 deg.C with the resultant distillate having <=600 deg.C boiling point as an emulsifying agent is preferably used as the above-mentioned oiling agent.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing carbon fibers and graphite fibers from carbonaceous pitch fibers. More specifically, the present invention relates to a pitch fiber firing method for obtaining long filament carbon fibers by spinning optically anisotropic carbonaceous pitch and subjecting it to infusibility, carbonization, and graphitization.

(Prior art) There has been a demand for the development of high-performance materials with properties such as light weight, high strength, and high modulus of elasticity in a wide range of technical fields related to automobiles, aircraft, and various other industrial fields. Carbon fiber or molded carbon materials are attracting attention. In particular, the method of manufacturing carbon fiber from carbonaceous pitch is regarded as important as a method that can manufacture carbon fiber with low cost and high performance.

However, with conventional techniques, pitch fibers have a low tensile strength of about 0.0 IGPa and are brittle, making them difficult to handle, making it difficult to obtain long filament fibers necessary for producing high-performance products. It was extremely difficult.

Conventionally, as a method for producing long filament carbon fibers from pitch fibers, the spun yarn is dropped into a wire mesh basket and deposited, the wire mesh is made infusible, and then the wire mesh is infusible.
After performing the first heat treatment at a temperature of 00°C or higher, the tensile stiffness of the yarn is Q, and the strength is 2GPa or higher.
A method has been proposed in which carbon fibers are obtained by carbonizing the fibers at a temperature of about 1500° C. after or while winding them up from the basket (Japanese Patent Publication No. 51-12740).

However, in this method, when the yarn is deposited,
It has a tendency to twist or twist, and is prone to paternal bending, which results in a yarn with extremely uneven appearance when made into carbon fiber, and the strength of the bent portion is significantly reduced, resulting in frequent yarn breakage and high The drawback was that the quality of the yarn was poor. These drawbacks cannot be essentially improved even if the curvature is increased when the threads are piled up.

On the other hand, special public service No. 53-4128? l [13, mesoface pitch is melt-spun, wound once on a bobbin,
Place some of the threads in a mesh tray and heat at 250℃ to 50℃.
Oxidizes in an oxidizing atmosphere at 0°C to increase the strength of the yarn,
A method for processing the yarn after making it easier to handle is disclosed. However, this method requires 400 to 500
The process is carried out in an oxidizing atmosphere at a temperature range of 30°F, and as the oxidation is carried out at too high a temperature, the sag of the final product, the carbon fiber thread, decreases. It has the disadvantage of poor production efficiency as it oxidizes.

JP-A-60-173121, JP-A-60-81320
No. 60-21911 discloses a method in which the bobbin winding is infusible and preliminary carbonization is performed in a non-oxidizing atmosphere at a certain temperature or lower. However, in these methods, when the thickness of the pitch fibers on the bobbin increases, fusion or agglutination between filaments tends to occur due to insufficient air permeability during infusibility or pre-carbonization, and after pre-carbonization, It is difficult to unwind (unwind) the thread on the bobbin, and during unwinding, the thread tends to become fluffy, which has the disadvantage of significantly reducing the commercial value of the thread when it is made into carbon fiber or graphite fiber.

Furthermore, due to insufficient air permeability, there is a large variation in the degree of infusibility, and when carbon fibers or graphite fibers are made, the strength variation is extremely large.

Japanese Unexamined Patent Publication No. 60-81320 discloses a method in which the pitch fibers are made infusible while wound on a bobbin, and then the infusible pitch fibers are unwound (unwound) from the bobbin to be carbonized and graphitized. This method is advantageous in that it can be unwound (unwound) at a stage where the degree of adhesion and fusion between fibers and fiber bundles is significantly lower than the method of infusibility and pre-carbonization while winding the bobbin. , the strength of the fibers is still weaker than that of pitch fibers, and during infusibility, the oil that binds the infusible fibers decomposes and deteriorates significantly.
The convergence of the fiber bundle is disturbed and the fiber bundle becomes extremely weak and brittle. For this reason, there was a drawback that unwinding (unwinding) after infusibility became extremely difficult. Furthermore, there is a drawback in that the yarn tends to become fluffy when unraveling. Also, due to insufficient ventilation,
There was a drawback that the degree of infusibility increased and the strength of carbon fibers or graphite fibers also greatly varied.

(Problems to be Solved by the Invention) Furthermore, in Japanese Patent Application Laid-open No. 55-128020, a yarn drawn by a godet roller after melt spinning is continuously passed through a hot air oven for infusibility at a yarn speed of 0.15 m/min. A method is disclosed in which carbon fibers are obtained by continuously passing the carbon fiber through a carbonization furnace. However, with this method, uniform infusibility can be achieved, so variations in physical properties are small, and when made into carbon fibers, yarns with good appearance can be obtained. The anionic water-soluble surfactant used as an oil agent decomposes and the focusing becomes disordered.
For this reason, there was a drawback that the fiber bundles were easily cut due to infusibility, making operation difficult.

This drawback can be solved by the method of emulsifying polysiloxane (silicone oil) with a surfactant and using it as a water emulsion type oil agent (Japanese Patent Publication No. 12739/1983), or by using other known surfactants or water emulsion type oil agents (Japanese Patent Publication No. 51/1989). -1274
No. 0, Japanese Patent Publication No. 53-10125, Japanese Patent Publication No. 1987-103
No. 313, etc.), the problem could not be solved. Therefore, during infusibility, the oil that binds the fibers decomposes and deteriorates, resulting in significant stickiness of the fibers, disordered bundles, and loss of flexibility of the fibers. For this reason, the conventional drawbacks that the fibers become tattered, the fiber bundles break, and yarn handling becomes difficult have not been solved.

On the other hand, a method of diluting polysiloxane with a solvent or the like may also be considered (JP-A-60-88124, JP-A-59
-223315, Japanese Patent Publication No. 51-12739, Japanese Patent Publication No. 47-36464), depending on the solubility of the solvent, etc.
It has the disadvantage that it is easily damaged, and this method also has the disadvantage that it is prone to adhesion and fuzzing. Furthermore, since a low-boiling point solvent or polysiloxane is used as a diluent, the diluent evaporates during work, which poses a major problem in terms of work and environmental protection, as well as high costs. Ta.

Furthermore, since the infusibility rate is slow, there is a drawback that the amount of product produced per hour is extremely small.

Therefore, there are no operational or environmental problems during operation, no cutting of fiber bundles during infusibility treatment (smooth operation, high product output per hour, and a good appearance of the yarn, which does not fuzz when handled). There has been a strong desire for a method to inexpensively and efficiently produce long filaments of pitch-based carbon fibers of high quality, with low carbon fiber resistance, high strength, high elasticity, and even yarn strength.

Therefore, an object of the present invention is to solve the above-mentioned drawbacks of the prior art and provide a method for producing pitch-based carbon fibers that are easy to handle and have high quality.

Another object of the present invention is to provide a method for efficiently producing high-quality pitch-based long filament carbon fibers that have a good appearance, high strength, and high elastic modulus.

(Means for Solving the Problems) This aspect of the present invention involves melt spinning pitch, doubling the spun pitch fibers, applying a water emulsion type heat-resistant oil, and then applying &ii fibers in an oxidizing atmosphere. This was achieved by a method for producing carbon fibers and graphite, which is characterized in that the bundle is passed continuously in a line to make it infusible, and then carbonized or graphitized in an inert gas atmosphere.

a) Carbonaceous pitch The carbonaceous pitch used in the present invention is not particularly limited, and includes coal tar pitch obtained by dry distilling coal;
Various pitches such as coal-based pitch such as coal liquefied products, naphtha cracked tar pitch, catalytic cracking tar pitch, petroleum-based pitch such as atmospheric distillation residue, vacuum distillation residue, synthetic pitch obtained by decomposing synthetic resin, etc. It is also possible to use pitch that has been hydrogenated with hydrogen or a hydrogen donor, or that has been modified by heat treatment, solvent extraction, etc.

The carbonaceous pitch of the present invention may be an optically isotropic pitch or an optically anisotropic pitch, and can also be applied to pitches called neomesoface and premesoface, but in particular, the following pitches may be used. The optically anisotropic pitch described in .

b- Optically anisotropic carbonaceous pitch The optically anisotropic carbonaceous pitch used in the present invention is obtained by polishing the cross section of a pitch lump solidified at room temperature and rotating crossed nicols using a reflective polarizing microscope. Pitches in which glitter is observed, that is, pitches in which the majority of pitches are substantially optically anisotropic, are used herein; pitches in which glitter is not observed and are optically isotropic are referred to herein as optically It is called isotropic carbonaceous pitch. Therefore, the optically anisotropic carbonaceous pitch in this specification includes not only a pure optically anisotropic carbonaceous pitch but also an optically isotropic phase in which the optically anisotropic phase is spherical or non-spherical. This also includes cases where it is contained in a fixed island shape.

Also, the case of substantially optical anisotropy means that optically anisotropic carbonaceous pitch and optically isotropic carbonaceous pitch coexist, but because the amount of optically isotropic pitch is small, This is a case where the optically isotropic phase (hereinafter referred to as IP) cannot be observed depending on the polarizing microscope described above, and only the optically anisotropic phase (hereinafter referred to as AP) is observed. Incidentally, in general, AP
A clear boundary is observed between IP and IP.

Present invention 1 [AP in Hf is considered to be the same as the so-called "meso phase," but the "meso phase" includes a component that is substantially insoluble in quinoline or pyridine, and a component that contains a large amount of components that are soluble in quinoline or pyridine. There are two types, and the AP referred to in the present invention 8I8 is mainly the latter "meso phase".

Since the AP phase and the IP phase are significantly different not only in optical properties but also in viscosity, it is generally not preferable to spin a pitch in which both are mixed, as this may cause yarn breakage or uneven thickness of the yarn. This means that even if the optically isotropic pitch does not contain foreign substances that are undesirable for spinning,
This means that particularly bad results occur if the IP phase is not homogeneously dispersed within the AP phase. Therefore, the optical anisotropic pitch used in the present invention is required to have substantial homogeneity. Such a homogeneous optically anisotropic pitch is I
The P content is 20% or less, solid particles with a particle size of 1 μm or more cannot be detected in the cross section of the pitch by reflection microscope observation, and there is substantially no foaming due to volatile matter at the melt spinning temperature.

In the present invention, AP and IP are quantified by observing under a polarizing microscope with crossed Nicols, taking a photograph, and measuring the area ratio occupied by the AP or IP portion. Represents %. However, the difference in specific gravity between AP and IP is about 0.05, which is small, so approximately vol%
and weight % can be treated as equal.

In the present invention, it is preferable that the softening point of the optically anisotropic pitch used is low. Here, the softening point of the pitch is the transition temperature between the solid phase and the liquid phase of the pitch, and the differential scanning calorific value It can be determined from the absorption or release peak temperature of latent heat during melting or solidification of pitch using a meter. The softening point measured by this method is ±
They agree within a range of 10°C.

Ordinary spinning techniques can be used for spinning in the present invention. Generally, the spinning temperature for melt spinning is 60°C to 100°C higher than the softening point of the material to be spun. On the other hand, the optical anisotropy pitch used in the present invention is 380
If the temperature is higher than 0.degree. C., thermal decomposition polycondensation may occur and decomposition gas may be generated or unmelted substances may be produced. Therefore, the softening point of the optically anisotropic pitch used in the present invention is preferably 320°C or lower, and the softening point of the optically anisotropic pitch used in the present invention is preferably 320°C or lower, and the
The temperature is preferably 30°C or higher.

b-2) Method for producing optically anisotropic pitch The optically anisotropic pitch used in the present invention may be produced using any production method, but heavy hydrocarbons, which are common raw materials for pitch production, may be used. Oil, tar, commercially available pitch, etc. are heated in a reaction tank at 380°C to 50°C.
A conventional method can be used in which the AP of the residual pitch is increased by thorough pyrolysis polycondensation with stirring at a temperature of 0° C. and bubbling with an inert gas. However, if a product with AP of 80% or more is manufactured using this method,
The thermal decomposition polycondensation reaction may proceed too much, and the quinoline dissolved content may increase to 70% by weight or more, and the softening point may reach 330°C or more. In addition, the IP may not be in a microspherical dispersed state, which is not necessarily preferable. I can't say it's a method.

Therefore, a preferred method for producing the optically anisotropic pitch used in the present invention is to terminate the pyrolysis polycondensation reaction halfway and maintain the polycondensate at a temperature in the range of 350°C to 400°C to substantially This is a method in which AP is allowed to stand still and deposited while growing and ripening in the lower layer, which has a high density, and is separated and taken out from the upper layer, which has a large amount of low-density IP. Details of this method are described in JP-A No. 57-119984. It is stated in the official gazette.

A more preferable method for producing the optically anisotropic pitch used in the present invention is a carbonaceous pitch that contains an appropriate amount of AP and is not yet excessively heavy, as described in JP-A-58-180585. In this method, the AP portion is rapidly precipitated by centrifuging it in a molten state. According to this method, the AP phase accumulates in the lower layer (layer in the direction of centrifugal force) while coalescing and growing, forming a continuous layer with about 80% or more of AP,
The lower layer has a pitch in which IP is slightly dispersed in the form of islands or minute spherical bodies, while the upper layer has mostly IP with AP dispersed therein in the form of minute spheres. pitch. In this case, the boundary between both layers is clear;
Only the lower layer can be separated and taken out from the upper layer, and optically anisotropic pitch that has a large AP content and is easy to spin can be easily produced. According to this method, carbonaceous pitch having an AP content of 95% or more and a softening point of 230°C to 320°C can be obtained economically in a short time. Such optically anisotropic carbonaceous pitch has excellent melt spinning processing properties, and due to its homogeneity and high orientation, the tensile strength and elastic modulus of carbon fibers and graphite fibers obtained by spinning it are excellent. will be extremely excellent.

c) Production of &gi fibers i) Spinning The above-mentioned pitch having a high AP content and a low softening point can be spun by a known method. In such a method, for example, pitch is placed in a metal spinning container having 1 to 1,000 spinnerets with a diameter of 0.1 mm to 0.5 mm below, and the pitch is heated at 280 to 280 mm in an inert gas atmosphere. Hold the pitch at a constant temperature between 370'C and keep it in the molten state with an inert gas pressure of several hundred m
The temperature is raised to mHg and the molten pitch is pushed out from the mouthpiece.
The pitch fibers are wound onto a bobbin that rotates at high speed while controlling the temperature and atmosphere.

In the present invention, uniform unwinding (
In order to perform (unwinding), the traverse during spinning is 2 to 100
It is wound with a large traverse such as mm/(per bobbin rotation), and the winding thickness is 1=lOOmm, preferably 5
It is effective to set the distance to 50 mm. The traverse is 5, considering the unwinding (unwinding) of the pitch fiber from the bobbin.
Approximately 20 mm/(one rotation of the bobbin) is preferable.

It is also possible to adopt a method in which pitch fibers spun from a spinneret are collected in a can-like manner in a lower collecting case while being collected by an air current.

In this case, continuous spinning is possible by supplying pitch to the spinning container by supplying pre-melted pitch under pressure using a gear pump or the like.

Furthermore, in the above method, it is also possible to use a method in which pitch fibers are drawn and taken up using gas that is controlled at a constant temperature near the die and descends at high speed, and long fibers are produced on a belt conveyor below.

Furthermore, a cylindrical spinning vessel having a spinneret on the peripheral wall is rotated at high speed, molten pitch is continuously supplied to the spinning vessel, the pitch is pushed out from the peripheral wall of the cylindrical spinner by centrifugal force, and the spinning vessel is drawn by the action of rotation. It is also possible to adopt a spinning method that accumulates pitch fibers.

In addition, in the present invention, even when spinning by any known method, optical fibers with a low softening point of 230°C to 320°C are used even though the AP content is as high as 95% or more. Since anisotropic carbonaceous pitch is used, 2
It is possible to spin at a lower temperature than conventional methods, such as 80°C to 370°C. When spinning at such temperatures, thermal decomposition and thermal polymerization can be suppressed to an extremely low level, so the pitch t after spinning is
The h-fibers can maintain almost the same chemical composition as the pitch before spinning. Therefore, it is convenient that the fibers after spinning can be remelted and spun again.

In the present invention, the melt-spun pitch fibers are bundled through an air sucker and then guided to an oiling roller where a sizing agent (oil agent) is applied and further bundled.

In this case, examples of the sizing agent include ethyl alcohol,
Alcohols such as isopropyl alcohol, n-propyl alcohol, butyl alcohol or viscosity 3-300c
St (25℃) dimethylpolysiloxane, methylphenylpolysiloxane, etc. diluted with a low boiling point silicone oil or paraffin oil or other solvent, or dispersed in water with an emulsifier added; Similarly, graphite or polyethylene glycol and hindered esters dispersed; surfactants diluted with water; and other oils used for ordinary fibers, such as polyester fibers, that do not harm pitch fibers. can.

In some cases, an antistatic agent may be added to these materials.

The amount of these oils attached to the fibers is 0.01 to 10% by weight, particularly preferably 0.05 to 5% by weight.

ii) Splicing of pitch fibers In the present invention, in order to increase the strength of the fiber bundle and to continuously and stably pass it through the infusibility furnace during infusibility, the pitch fibers are made into gold threads prior to infusibility.

The number of pitch fiber filaments that can be spun from 1311 melt spinning units (one spinneret) is limited due to melt spinning.
Usually 1 to 2,000, preferably 50 to 1,0
00 filament.

In the present invention, 2 to 2 pitch fiber bundles obtained by melt spinning are used.
using 0, 200 to so, ooo, preferably 500
Splice into ~5,000 filaments.

In the doubling process, the spun pitch fibers are wound around multiple bobbins and then simultaneously unwound, the fiber bundle is divided into 19 pieces, and 1
This is done by winding it onto a No. 9 bobbin.

Traverse during doubling is 5 to 100 m per bobbin rotation
It is preferable that it is m. In order to improve the unwinding property from the bobbin, it is better to make the traverse larger, but if it is too large, the thread is likely to be damaged, so it is not preferable.

Pitch fibers dropped into cans may be pulled up from a plurality of baskets or cases and combined.

Doubling can be performed not only by unwinding from a bobbin, but also by gathering and doubling pitch fibers spun simultaneously from a plurality of spinning machines or spinnerets.

Although 2 to 20 yarns may be doubled at a time, a method of doubling 2 to 10 yarns at the first time and then re-splicing 2 to 10 yarns is also used.

In order to improve the thread-pairing property and the cohesiveness during infusibility, twisting of 0.1 to 30 twists/m, preferably 1 to 5 twists/m is added as necessary during the thread-pairing stage.

In the present invention, in order to ensure stable thread passing through the infusibility furnace during infusibility, a special heat-resistant water emulsion-based oil agent is applied at the time of yarn doubling. As the oil agent, a water emulsion type is particularly preferable from the viewpoints of workability, environment, and manufacturing cost.

In the present invention, as a heat-resistant water emulsion oil agent, a distillate with a boiling point of 600°C or less (atmospheric pressure equivalent) obtained by distilling a nonionic surfactant under reduced pressure is used as an emulsifier, and 10
An emulsified alkyl phenyl polysiloxane having a viscosity of ~1000 cst is used.

As the nonionic surfactant, polyoxyethylene alkyl ether and polyoxyethylene alkyl ester are used.

The alkylphenyl polysiloxane preferably contains 5 to 80 mol% of phenyl groups as a component,
Particularly preferred is one containing 10 to 50 mol%.

Moreover, as the alkyl group, a methyl group, an ethyl group, and a propyl group are preferable. The same molecule may have two or more types of alkyl groups.

With this combination, a water emulsion type oil can be made, and the decomposition and deterioration of the oil during infusibility is significantly reduced.
The fiber bundles are well bundled, the fiber bundles are not cut during infusibility, and there is little fluff, and they can be passed through the infusibility furnace continuously in a linear form.

Nonionic surfactants are used as emulsifiers without distillation,
When an emulsified alkyl phenyl polysiloxane is used, the oil agent that binds the fiber bundles decomposes and deteriorates during infusibility, and the bundles become disordered, making it easy for the fiber bundles to break.
It becomes difficult to handle the thread.

Also, dimethyl polysiloxane (dimethyl silicone oil)
, fatty acid ester oil, mineral oil, etc. can be emulsified with ordinary surfactants, but compared to when alkylphenyl polysiloxane is used, the decomposition and deterioration of the oil agent and the sticking of fiber bundles occur during infusibility, making it even more difficult to handle the yarn. It becomes difficult.

On the other hand, even if an attempt is made to emulsify dimethylpolysiloxane (dimethylsilicone oil) with a distilled nonionic surfactant, emulsification is difficult and it cannot be used as a water emulsion type oil agent.

In order to further improve the heat resistance of the oil agent, antioxidants such as amines, organic selenium compounds, and phenols may be added to the oil agent.

As these antioxidants, phenyl-α-naphthylamine, dilaurylselenide, phenothiazine, iron octolate, etc. are used.

The oil may be applied by any method such as roller contact or spraying.

The amount of these oils attached to the fibers is 0.01 to 10% by weight,
Preferably it is 0.05 to 5% by weight.

The winding thickness after the yarn doubling can be set arbitrarily, but from the viewpoint of workability and operability, it is set to 10 to 100 mm.

The threads may be combined before being threaded through the infusibility furnace, or may be infusible while the threads are being combined.

iii) Infusibility of pitch fibers In the present invention, infusibility is achieved by continuously passing the fiber bundle through an oxidizing atmosphere.

In the present invention, the yarns are doubled so that continuous yarn threading can be smoothly carried out, and a heat-resistant oil is applied to prevent the fiber bundle from breaking during the infusibility treatment, so the pitch fibers are oxidized and the infusible carbon Various known combinations of temperature, oxidizing agent, and reaction time in the step of producing quality fibers can be used.

The temperature of the infusibility step in the present invention is 150°C to 400°C
The temperature is preferably increased stepwise or gradually in the range of 200° C. to 300° C., and the treatment is usually carried out for 30 minutes to 5 hours.

Infusibility can be performed using air, oxygen, a mixed gas of air and oxygen, or air and nitrogen, or the like.

In the present invention, even if the oxygen concentration is increased, there is no fear of combustion due to accumulation of reaction heat within the fiber bundle, so it can be used as a method for shortening reaction time.

In the present invention, halogen and N
Sufficient infusibility can be obtained by treatment for a short time in an atmosphere containing an oxidizing agent such as O2 or ozone, or at a temperature 30 to 50 degrees Celsius lower than the softening point of pitch, i.e., at a temperature of 150 to 240 degrees Celsius, in an oxygen gas atmosphere. It is preferable to hold the mixture for 10 minutes to 1 hour until the mixture is obtained, and then raise the temperature to about 300° C. if necessary to complete the infusibility, and the latter method is particularly preferred because it is easy and reliable.

For infusibility, it is preferable to circulate and replace fresh gas of the same type as the atmosphere at a rate of 0.1 to 3 times per minute to discharge old gas.

The atmosphere during the infusibility treatment is preferably forcibly stirred by a fan, and the wind speed is 0.1 to 10 m/sec, preferably 0.5 to 5 m/sec.

Such forced stirring promotes gas penetration into the fiber bundle, eliminates temperature distribution in the infusibility furnace, and has the effect of making firing uniform.

During the infusibility treatment, it can be done without applying tension, but in the infusibility furnace, the fiber bundles (threads) sag and rub against the bottom and walls of the furnace, resulting in drag scratches. Infusibility is performed while applying a tension of 0.001 to 0.2 g per filament in order to improve carbon fiber physical properties such as tensile strength and tensile modulus.

The fiber bundle that leaves the continuous infusibility furnace becomes weak and brittle due to decomposition, evaporation, deterioration, etc. of some of the oil in the furnace, so a heat-resistant oil is applied again and the fiber bundle is treated as yarn. It is more preferable to improve the properties.

1v)v3! Treatment Step Next, this infusible carbonaceous pitch fiber is heated for 10 minutes in an atmosphere of chemically inert argon or nitrogen gas.
Carbon fibers can be obtained by raising the temperature to a temperature in the range of 00 to 2000°C and carbonizing it, and when the temperature is raised to a temperature in the range of 2000 to 3000°C and proceeding to graphitization treatment, so-called graphite fibers are obtained. is obtained.

In the present invention, the details of the carbonization and riverboat conversion methods are not particularly limited, and generally known methods can be used.

(Effects of the Invention) The present invention increases the strength of the fiber bundle by doubling carbonaceous pitch fibers, and further applies a heat-resistant oil to the fiber bundle to continuously infusible it in a linear manner. There is no cutting of fiber bundles during melting, and production speed can be increased.

In particular, since a water emulsion-based oil is used, there is no risk of damage or fusion of the yarn.In addition, there are no major operational and environmental problems such as infusibility during yarn doubling, and carbonization and graphitization are also continuous. This makes it possible to use continuous equipment, and to obtain carbon fibers and graphite fibers with good appearance, uniform tensile strength, and high physical properties such as tensile modulus.

In particular, when optically anisotropic carbonaceous pitch fibers are used, the strength and elastic modulus are further improved.

As mentioned above, production efficiency is extremely high, efficient,
Carbon fibers and graphite fibers with high strength and high 311 elasticity can be obtained.

(Examples) Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 Contains about 55% optically anisotropic phase (AP), 16.1% by weight of soft insoluble matter, 0.26% by weight of natural matter, and has a viscosity at 370°C. showed 2.8 voices. Contents of this pitch [20j! melted in a melting tank of 3
Controlled at 70℃, the effective volume inside the rotor [200m7! Send it to the cylindrical continuous centrifugal paving port at a flow rate of 20 ml/min.
While controlling the rotor temperature at 370℃, the centrifugal force is
At 000G, a pitch with more optical anisotropy than the AP outlet (A pitch) and a pitch with more optical isotropy than the IP outlet (■ pitch) were successively extracted.

The optically anisotropic pitch obtained is 98 times the optically anisotropic phase.
%, the softening point was 265°C, and the quinoline solubility was 29.5% by weight.

Next, the obtained optically anisotropic pitch was melt-spun with a 500-sized spinning nozzle (nozzle hole diameter: 0.3 m in diameter).
m), extruded at 355°C with a nitrogen gas pressure of about 200 mmHg, and wound around a stainless steel wire mesh bobbin with a diameter of 210 mm and a width of 200 mm that rotates at high speed, installed at the bottom of the nozzle, and wound at a rate of about 500 m/min. Spun at speed for 10 minutes. The pitch of the traverse per revolution of the bobbin was 10 mm/rotation. There was no yarn breakage during spinning. At this time, the spun yarn is approximately converged by an air sucker and guided to an oiling roller, and is approximately 0.5% by weight based on the yarn.
The focusing oil was supplied at a ratio of .

As the oil agent, dimethylpolysiloxane having a viscosity of 14 cst at 25° C. was used.

Six bobbins wound with pitch fibers were combined at a traverse pitch of 20 mm/rotation, and 3,000 filaments were wound around a stainless steel bobbin.

At the time of yarn doubling, 4Qcst methylphenylpolysiloxane (25 mol% of phenyl) was distilled under reduced pressure from polyoxyethylene alkyl ether with a number average molecular weight of 1000, which is a nonionic surfactant, and the mixture was distilled under normal pressure. Conversion 6
A water emulsion type oil agent was used which was emulsified using a distillate up to 00°C as an emulsifier.

The water emulsion oil had a concentration of 0.5% by weight and was applied by roller contact. The amount applied was 0.2% by weight based on the yarn.

While unwinding (unwinding) the bobbin-wound pitch fiber obtained in this way from the bobbin, the furnace inlet temperature was 150°C, and the maximum temperature was 2.
The mixture was continuously introduced in a linear manner into a continuous infusibility furnace with forced hot air circulation equipped with a fan in an air atmosphere with a temperature gradient of 70°C. Temperature from 150℃ to 270℃ at 11/min, 270℃
It was held for 30 minutes.

Treatment time was 150 minutes. During this time, the atmosphere inside the furnace is reduced to 0.
．． Replacement was performed at a rate of 5 times/min. The wind speed at the time of infusibility is 0.7
m/sec, the tension applied to the fiber bundle is 0°007 g/1
It was per filament.

During this time, the pitch fibers were smoothly unwound from the bobbin.

After completion of infusibility, the same oil agent used for doubling was applied by roller contact.

This infusible pitch fiber was heated for 1 hour in an inert gas atmosphere.
The temperature was raised to 500°C to obtain carbon fibers.

The diameter of the carbon fiber is 9.9 μm, and the tensile strength is 2
．． 7 GPa, and the tensile modulus was 260 GPa.

In addition, this carbon fiber was heated to 250Q'c in an inert gas atmosphere.
The graphite fiber obtained by raising the temperature to 2.5 GPa had a thread diameter of 2.5 GPa and a tensile modulus of 710 GPa.

Example 1 except that polyoxyethylene alkyl ether, a nonionic surfactant, was used as it was without being distilled under reduced pressure.
processed in the same way. In this case, the oil agent decomposed, deteriorated, and stuck in the furnace during the unmelting process, causing the fibers to become tattered and the fiber bundles to be cut.

Comparative example 2゜ The process was carried out in the same manner as in Example 1, except that the yarns were not doubled.

In the thus obtained pitch fibers, the fiber bundles were cut in the furnace during infusibility, making it impossible to obtain long infusible fibers.

Comparative Example 3 The process was carried out in the same manner as in Example 1, except that the heat-resistant oil was omitted during doubling. In this case, the fiber bundles were frequently cut during the continuous infusibility furnace, making it impossible to obtain long fibers.

Comparative Example 4 The process was carried out in the same manner as in Example 1, except that methylpolysiloxane having a viscosity of 28 cst was emulsified with sodium lauroyl sulfonate, a surfactant, as the oil applied during yarn doubling. The amount of adhesion to the fibers was the same as in Example 1.

In this case, during infusibility, the oil agent decomposed and deteriorated in the furnace, the fibers were severely stuck together and crumbled, and the fiber bundles were cut.

Comparative Example 5 Carbon black 3.6 was added as an oil agent during doubling.
The treatment was carried out in the same manner as in Example 1, except that a material consisting of 0.8% by weight of ammonium persulfate and 0.4% by weight of ammonium laurate, which is a water-soluble surfactant, was used.

In this product, the oil agent decomposed and the fiber bundles were cut in the furnace during infusibility.

Patent Applicant Fuji Photo Film Co., Ltd. Agent Patent Attorney Kiyoshi Takita (and 1 other person) Mon-Dai Nailt Seisho (December 21, 1985) Indication of the case 1 horse (z) 1 for patent filed on December 26, 1985
[3. Relationship with the case of the person making the amendment Patent applicant address 1-1-1, Chiyoda-ku, Tokyo - Tsubashi Name Toa Fuel Industry + bc Company representative Akira Matsuyama 44LT 4 people Address 160 8th floor, Ueki Building, 2-41-8 Kabukicho, Shinjuku-ku, Tokyo? wJ (208) 8471 Name (8763) Bennatakita Ukeki Address 1-1 Tsuhashi, Chiyoda-ku, Tokyo
The process was carried out in the same manner as in Example 1, except that 9% of 11 rum was used.

In this product, the oil agent decomposed and the fiber bundles were cut in the furnace during infusibility.

Claims (1)

[Claims] 1) After melt-spinning carbonaceous pitch, doubling the spun pitch fibers, and applying a water emulsion-based heat-resistant oil, the fiber bundles are continuously linearized in an oxidizing atmosphere. A method for producing carbon fibers and graphite fibers, which is characterized in that carbonization or graphitization is performed in an inert gas atmosphere. 2) The number of filaments of the pitch fibers before being spun with a melt spinning machine is 50 to 1,000 filaments, and the number of filaments of the pitch fibers after being spun is 200 to 50,000 filaments.
The method for producing carbon fibers and graphite fibers according to claim 1, wherein the carbon fibers and graphite fibers are 0 filaments. 3) A patent characterized in that the spun pitch fibers having a predetermined number of filaments are obtained by winding the spun pitch fibers around a plurality of bobbins, and then unwinding and doubling the spun pitch fibers. A method for producing carbon fibers and graphite fibers according to claim 2. 4) Pounded pitch fibers having a predetermined number of filaments are obtained by collecting the spun pitch fibers using an air current after convergence, accumulating them in a can-like accumulation container, and then unraveling them and doubling them. The second claim characterized in that
The method for producing carbon fibers and graphite fibers as described in 2. 5) Pounded pitch fibers having a predetermined number of filaments are obtained by continuously doubling pitch fibers spun from spinnerets of a plurality of spinning machines while spinning. A method for producing carbon fibers and graphite fibers according to Scope 2. 6) According to claim 2, wherein the spun pitch fibers having a predetermined number of filaments are obtained by re-unwinding the once spun pitch fibers and performing re-splicing. The method for producing the carbon fiber and graphite fiber described above. 7) Traverse at the time of doubling 5 to 100 mm/(Bobbin 1
3. The method for producing carbon fibers and graphite fibers according to claim 2, wherein the method comprises: rotation). 8) The method for producing carbon fibers and graphite fibers according to claim 2, characterized in that the yarns are twisted 0.1 to 30 times per meter during doubling. 9) The water emulsion oil applied to the spliced pitch fibers has a boiling point of 6 obtained by distilling a nonionic surfactant under reduced pressure.
Using a distillate of 00°C or less (boiling point equivalent to atmospheric pressure) as an emulsifier,
The method for producing carbon fibers and graphite fibers according to claim 1, wherein the emulsified alkyl phenyl polysiloxane having a viscosity of 10 to 1000 cst at 25°C. 10) The method for producing carbon fibers and graphite fibers according to claim 9, wherein the alkylphenyl polysiloxane contains 5 mol% to 80 mol% of phenyl groups. 11) A patent claim characterized in that the alkyl group of the alkylphenylpolysiloxane has a methyl group, an ethyl group, a propyl group, or two or more same or different groups selected from these. A method for producing carbon fibers and graphite fibers according to Scope 9. 12) The method for producing carbon fibers and graphite fibers according to claim 9, wherein the nonionic surfactant is polyoxyethylene alkyl ether or polyoxyethylene alkyl ester. 13) In the heat-resistant oil agent, amines, organic selenium compounds,
The method for producing carbon fibers and graphite fibers according to claim 1, which contains an antioxidant such as phenols. 14) The antioxidant is phenyl-α-naphthylamine,
14. The method for producing carbon fibers and graphite fibers according to claim 13, wherein the fiber is one or a mixture of two or more selected from dilaurylselenide, phenothiazine, and iron octolate. 15) Infusibility treatment at a temperature range of 150°C to 400°C,
The method for producing carbon fibers and graphite fibers according to claim 1, wherein the method is carried out in an atmosphere of air, oxygen, or a mixed gas of air and oxygen or air and nitrogen. 16) The method for producing carbon fibers and graphite fibers according to claim 1, wherein the infusibility is carried out in an atmosphere containing an oxidizing gas such as halogen, NO_2, and ozone. 17) The method for producing carbon fibers and graphite fibers according to claim 1, characterized in that the infusible atmosphere gas is circulated and replaced at a rate of 0.1 to 5 times/minute. 18) The method for producing carbon fibers and graphite fibers according to claim 1, wherein the infusible atmosphere is forcibly stirred at a wind speed of 0.1 to 5 m/sec. 19) 0.001 to 0.00% per filament during infusibility.
The method for producing carbon fibers and graphite fibers according to claim 1, characterized in that a tension of 2 g is applied. 20) The carbonaceous pitch is an optically anisotropic pitch, the optically anisotropic carbonaceous pitch contains about 95% or more of an optically anisotropic phase, and has a softening point of about 230 to 320°C. The method for producing carbon fibers and graphite fibers according to claim 1, characterized in that: