JPS58196293A - Preparation of optical anisotropic pitch and raw material for preparing it - Google Patents

Abstract

PURPOSE:To obtain efficiently and inexpensively optical anisotropic pitch having a low softening point to prepare carbon products, by adding a specific hydrocarbon fraction(mixture) to residual oil of a catalytic cracking device, subjecting the blend to polycondensation through thermal decomposition. CONSTITUTION:(A) A residual oil of a catalytic cracking device is blended with (B) about 15-50wt% hydrocarbon fraction(mixture) having >=0.4 aromatic carbon fraction fa and about 200-400 deg.C boiling point to give a raw material, which is subjected to polycondensation through thermal decomposition, to give the desired optical anisotropic pitch. The raw material has preferably about 200 deg.C initial boiling point, 15-40% running point of about 400 deg.C and 90% running point of about <=540 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for efficiently producing optically anisotropic pitch having a low softening point for producing carbon products from catalytic cracker residual oil.

Catalytic cracking reactions have traditionally been commonly used in the petroleum and petrochemical industries to convert gas oil fractions containing aromatic, naphthi/paraffinic, and paraffinic hydrocarbons into lighter and more useful products. The method of using

Although various important light fractions can be obtained through this process, the residual oil produced as a by-product from the catalytic cracking unit is not fully utilized, and therefore, the value of the residual oil is limited. Ta. Taking note of the low cost of catalytic cracker residual oil, in recent years it has been used to produce various high-performance carbon products produced by thermal decomposition of organic materials, such as carbon fibers, carbon films, and carbon ribbons. Attempts have been made to use it as a raw material for materials such as carbon sheets.

In particular, high-performance carbon fiber, which has high strength and high modulus, is extremely excellent as a material for high-performance composite materials, and despite its high manufacturing cost, its demand continues to increase. It is important to develop inexpensive raw materials and manufacturing methods to reduce manufacturing costs. From this point of view, the production of carbon fibers from inexpensive carbonaceous pitch, which has been developed in recent years, has been attracting attention, and the present invention also belongs to this field.

Conventionally, many carbonaceous pitches and tars are converted into optically anisotropic phases through pyrolysis polycondensation reactions, resulting in liquid crystal substances, and carbon fibers manufactured from optically anisotropic pitches thus converted. It is known that carbon fiber has high modulus, high strength, and extremely high performance (US Pat. No. 4,005,183). Along with this, traditionally,
Many studies have been conducted on methods for producing optically anisotropic pitch, which is necessary for producing high-performance carbon fibers, and some methods have already been disclosed (for example, Japanese Patent Publication No. 49-86
No. 34, JP-A-56-89635, 50-1
18028 Publication, 54-55625 Publication, 56-1
No. 67788 Kokamo). In each case, these conventional methods produce homogeneous, low softening point, optically anisotropic pitch, suitable for producing high-performance carbon products, especially high-performance carbon fibers, at low cost and in large quantities. It had the disadvantage that it could not be provided in a stable manner.

The present inventor conducted various studies on the composition of optically anisotropic pitch in order to eliminate such drawbacks of the conventional technology. Pitch has good orientation, but in reality, a variety of pitches exist, and among them, those with a low softening point and suitable for producing homogeneous carbon fibers have a specific chemical structure and composition. I found it. That is, in the optically anisotropic pitch, the n-hebutane soluble component (hereinafter referred to as "o" component)
t), and n-hebutane-insoluble and benzene-soluble components (
It is important to note that not only the structure and molecular weight of the rAJ component (hereinafter referred to as rAJ component) but also their content are extremely important for the overall properties of the optically anisotropic pitch. is insoluble in benzene, but by identifying the quinoline-soluble component (hereinafter referred to as "B" component) and the quinoline-soluble component (hereinafter referred to as "C" component),
J[AJ rBJ rcJ It has been discovered that by balancing each component, it is possible to obtain a pitch that is substantially homogeneous and has extremely excellent properties as an optically anisotropic pitch for producing high-performance carbon materials ( Patent application 1977-1.62
No. 972). Furthermore, we conducted research on the relationship between the characteristics of optically anisotropic pitch and the characteristics of the raw material.9 As a result, we found that the presence of aromatic oil and resin content is important for a good raw material. It turned out (Special Application No. 11124/1982)
Based on these findings, in order to efficiently produce optically anisotropic pitch with excellent properties using the residual oil from a catalytic cracker as a raw material, it is necessary to incorporate a low molecular weight into the residual oil. The present invention was achieved by discovering that it is preferable to contain an appropriate amount of aromatic components.

Therefore, the first object of the present invention is to provide a raw material for efficiently producing optically anisotropic pitch having excellent properties necessary for producing high-performance carbon products such as carbon fibers at low cost. That's true. The second purpose of the present invention is to produce optically anisotropic pitch, which has excellent properties and is a precursor for producing high value-added carbon products with high efficiency, from catalytic cracker residue/oil. An object of the present invention is to provide a method for producing sudame. Furthermore, the third object of the present invention is to produce optically strong pitch having excellent properties as a precursor for producing high value-added carbon products with high efficiency using catalytic cracker residual oil. We proposed a method for continuous production (, l
It is to do L.

That is, the first aspect of the present invention is to provide ``catalytic cracker residual oil with an aromatic carbon fraction fa of 0.4 or more and a hydrocarbon fraction having a boiling point of about 2006C or more and about 400'C or less, or these fractions. The second invention is an original optically anisotropic pitch characterized by containing a mixture of An optical system characterized in that the residual oil of a catalytic cracking unit containing an aspect ratio hydrogen fraction having a boiling point of 4006C or more and about 4006C or less, or a mixture thereof, is used as a raw material and subjected to a pyrolysis polycondensation reaction. This is how the directional pitch is manufactured.

In the present invention, catalytic cracking refers to catalytic cracking of soluble oil fractions, gas oil fractions, and other heavy oil fractions, especially straight-run gas oils with boiling points between about 200'C and about 600'C, using a catalyst. Catalytic cracker residual oil refers to oil produced by catalytic cracking with a boiling point of about 400.
It refers to residual oil whose main component is hydrocarbon components with a temperature of ℃ or higher. Due to the conditions of the distillation operation after removal from the catalytic cracker, this catalytic cracker residue oil contains components with a lower boiling point than the original feedstock oil. In some cases, there are only components that have a boiling point. Generally, catalytic cracker residue oil contains only a small amount of components having a molecular weight of about 1,000 or more, but if it contains 50 or more by weight of such components, it is preferable to remove them. Furthermore,
Although the residual oil from the catalytic cracking apparatus contains fine powder of the cracking catalyst and a trace amount of solid matter, it is preferable to remove them to a level of 0.01 weight or less.

JP-A-56-167788 discloses a method for producing optically anisotropic pitch, which comprises removing a fraction having a boiling point of about 400'C or less from the catalytic cracker residual oil and then heat-treating it. Disclosed. That is, in this invention,
It is preferred that the fraction below about 400'C contained in the catalytic cracker residual oil is not present. However, in the catalytic cracker residual oil in the present invention, the presence of the above-mentioned fraction of 400'C or less is rather preferable, and the step of taking the trouble of distilling it off is completely unnecessary. Japanese Patent Publication No. 56-16778
The reason why there is such a remarkable difference between the invention disclosed in Publication No. 8 and the present invention is precisely because the present invention
This is because the invention was made based on the knowledge obtained in the inventions disclosed in No. 5-162972 and Japanese Patent Application No. 11124/1982. That is, JP-A-56-16
The method disclosed in Publication No. 7788 is based on a different idea, and the method of rOJ, rAJ, "B", and "C" components is obtained by removing as much of the low molecular weight substances as possible with one solvent extraction regardless of the lance. However, the present invention is suitable as a method for producing optically anisotropic pitch containing a large amount of relatively high molecular weight optically anisotropic pitch.
This is because there is a fundamental difference between the two inventions because the balance of each component "A", "B", and "C" is most important. Therefore, in the case of the method of JP-A-56-167788, the optically anisotropic pitch produced tends to contain components with high softening points, and a complicated process of removing them with a solvent is required. On the other hand, in the case of the present invention, such complicated steps are not required at all, and the entire manufacturing process is extremely simple.
゛It is abbreviated. In the present invention, the fraction having a boiling point of about 2006C or more and about 400C or less contains a large amount of low-molecular aromatic hydrocarbons, and their presence can be reduced to the above "0" by a short reaction. ,FA'',r,B J,rCJ
It has the function of reducing the softening point of the optically anisotropic pitch while maintaining the orientation and homogeneity of the optically anisotropic pitch. This is based on the fact that there is a causal force τ between the orientation, homogeneity (or compatibility), and softening point and the molecular structure of the pitch.

First, the orientation of the optically anisotropic pitch is related to the planar structure of the molecules and the fluidity of the liquid at a certain temperature. That is,
The planar structure of the pitch molecules is sufficiently large, and the liquid fluidity is sufficiently large to rearrange the =y plane of the molecules in the fiber axis direction during melt spinning; high orientation. This is a necessary condition for pitch damage. The planar structure of the molecule is determined by the size of the fused polycyclic aromatic, the number of naphthene rings, the number and length of side chains, etc. ．． It is possible to calculate the value of -tjf by fa, which is the ratio of total carbon atoms to total carbon atoms. faIl'1 in the present invention, infrared absorption spectrum tears 1) From the fixed result, Kato's method (Fuel Association Journal 55, 2
44 (1976)), but in general, fa
In general, the larger the fused ring aromatic group, the fewer the number of naphthene rings, the smaller the number of side chains; Specifically, f
Red with a large a means that the molecule has a large planar structure. This power is raw material.

It is understood that it is preferable that a large amount of aromatic hydrocarbons be contained, as this increases the planar structure of the optically anisotropic pitch molecule that is the product. If the planar structure of the molecule improves,
As the optical anisotropic pitch becomes larger, it becomes easier for molecules to align in the fiber axis direction during spinning, making it easier to produce high-performance carbon fibers. . Therefore, there is no need to increase the molecular weight of the optically anisotropic pitch molecules more than necessary due to excessive reaction to increase the content of the optically anisotropic phase and its orientation. That is, even if the molecular weight of the optically anisotropic pitch is lowered, the performance of the carbon fiber is not only sufficiently maintained, but also the benefits of ease of spinning become greater. This means that containing a large amount of relatively low molecular weight aromatic hydrocarbons in the raw material increases the planar structure of the optically anisotropic pitch molecules and at the same time reduces the average molecular weight, thereby increasing the optical anisotropy. This means "leading to the result of lowering the softening point of the optically anisotropic pitch," and therefore, it is also possible to sufficiently carry out the reaction and increase the homogeneity of the optically anisotropic pitch.

This is why, in the present invention, the catalytic cracker residual oil is actively made to contain a hydrocarbon fraction with an fa of 0.4 or more and a boiling point X of about 2000C or more and about 4006C or less. Even if there are too many fractions with boiling points above about 2006C and below about 400'C, "0", "A", "B", "C
It becomes difficult to take a lance of each component. Therefore, the fraction of about 2006C or more and about 4006C or less is about
13% by weight - about 50% by weight, preferably about 15% by weight
The content is preferably about 40% by weight. To adjust the content needle, these fractions are distilled from the catalytic cracker residual oil containing a large amount of these fractions, or these fractions are added to the catalytic cracker residual oil that contains a small amount of these fractions. This can be easily done by doing this. The fractions include cracked gas oil fractions from catalytic crackers, cracked gas oil fractions obtained from thermal crackers, such as naphtha and steam crackers, and cracked gas oils from coal liquefaction equipment.
can be used. In addition, the swelling hydrogen component having a small molecular weight and a low boiling point undergoes a slow thermal polycondensation reaction, reducing the final yield of pitch. Taking such phenomena into consideration comprehensively, the boiling point and fa of the hydrocarbon fraction to be used are specified in the implementation of the present invention.

In this way, embodiments of the prepared raw materials include:
fa is 0.4 or more, the initial boiling point force is about 200°C or more, the distillation point of 15% to 40% by weight is about 400'C, and the distillation point of 90% by weight is 75; 54'0°C or less. The reason why the 90% distillation point increases to more than about 540'C is because it contains a component with a significantly high molecular weight.
This is not preferable because it makes the softening point of the generated pitch abnormally high.

The predetermined raw material obtained in this way is ITI':
:p, 41t, the optically anisotropic pitch has a low softening point of about 230°C-1, although the optically anisotropic Pt phase content is as high as 90 to 100 volume parts. *
320°C, suitable for producing charcoal products.

In particular, when carbon fibers are produced by melt spinning, the spinning temperature can be lowered, and the spinning temperature is good, which is extremely convenient for producing high-performance carbon fibers.

When the raw materials of the present invention are used, optically anisotropic pinches produced by a production method such as "0", "A", etc.
, ``B'', and ``C'' components have good properties and a low softening point. For example, a method using a catalyst such as aluminum chloride may be used, or a pyrolysis polycondensation reaction without using a catalyst and, if necessary, a subsequent dissolved 1 extraction method may be used. If necessary, the mixture may be stirred and an inert gas may be added to the mixture, or the reaction may be carried out under increased pressure or reduced pressure. Here, the pyrolysis polycondensation reaction is a reaction in which the pyrolysis reaction of hydrocarbons in the raw material and the polycondensation reaction proceed in parallel as main reactions, producing an optical anisotropic pinch. This is thought to be mainly due to the development of a planar structure of polycyclic condensed aromatics due to paraffin chain scission, dehydrogenation, ring closure, and polycondensation.

The temperature of the pyrolytic polycondensation reaction to produce optically anisotropic pitch is about 3806C to about 460IC, preferably
About 400'C to about 440@C. If the temperature is too low, the reaction will take a long time, and if the temperature is too high, the softening point of the optically anisotropic pitch produced will become high, which is not preferable.

When using the raw material of the present invention, approximately 2 kg/cm2
A preferred method is to carry out pyrolysis polycondensation under a pressure of ~50 kg/cm 2 and then heat under an inert gas flow to remove low molecular weight substances.

As in the case of Japanese Patent Application No. 56-11124, it is possible to further connect the process of producing optically anisotropic pitch with the process of separating the produced optically anisotropic pitch by these methods. This is also extremely effective in the case of the present invention. In other words, this is a method of separating the optically anisotropic pitch produced during the process of pyrolysis polycondensation reaction. Since the raw material of the present invention has a large content of relatively low molecular weight aromatic components, it also contributes to preventing the optically different method pitch produced by the reaction from becoming larger than necessary; The method of separating the optically anisotropic pitch produced during the process of the above-mentioned pyrolysis polycondensation reaction means that the optically anisotropic pitch produced can be kept at a high temperature until the end of the process. In order to avoid this problem, it is possible to prevent the molecular weight from increasing more than necessary due to the optical anisotropy pinch polycondensation reaction proceeding more than necessary. It's even more convenient for getting a sexual pitch.

In order to separate the optically anisotropic pitch produced during the process of the pyrolytic polycondensation reaction, the pyrolytic polycondensation reaction must be carried out until the optically anisotropic pitch produced is about 20 volumes to about 80 volumes. When the temperature reaches 1, the reaction tank is stopped and the reaction tank is left virtually stationary, while the temperature is maintained at a temperature at which the thermal decomposition polycondensation reaction is difficult to occur and the fluidity of the pitch as a fluid is maintained sufficiently, that is, approximately 350'C to about 400'C, preferably about 360'C to
By maintaining the temperature at approximately 390'C, the optically anisotropic phase with a higher density in the lower layer is allowed to grow and mature as one continuous phase and is deposited, and this is combined with the isotropic pinch in the upper layer with a lower density. It is sufficient to separate the phase containing the most amount, but as disclosed in Japanese Patent Application No. 57-052731, by providing a reaction zone and a standing zone in one reaction tank, it can function as a reaction tank and at the same time as a sedimentation separation tank. By providing a single reaction tank with this function, both the pyrolysis polycondensation reaction step and the separation step of the produced optically anisotropic pitch can be continued continuously. That is, by making the upper part of the reaction tank a stirred reaction zone and the lower part of the reaction tank a substantially static area, if the raw material of the present invention is continuously injected from the top of the reaction tank, the raw material of the present invention can be continuously injected from the bottom of the reaction tank. Optically anisotropic pitch having a low softening point and excellent properties can be continuously extracted. Further, the pitch partially containing optically anisotropic pitch is subjected to a centrifugation operation in its molten state to efficiently and continuously separate the optically anisotropic pitch, which is a phase with a higher specific gravity. be able to. The centrifugation operation conditions are about 2606C to about 390"C, preferably about 3306"C.
at a temperature of from about 360'C to about 10,0009°C,
Preferably, a centrifugal acceleration of about 5 degrees to about 3 degrees can be employed. However, 7 here is the gravitational acceleration.

When the raw material of the present invention is used, JP-A-56-+67
Not only can the distillation operation under severe conditions as disclosed in Publication No. 788 be omitted, but since there are many low molecular weight aromatic hydrocarbon components, the viscosity of the reactant is relatively low, and the pipe transfer and stirring of the raw materials are easy. Not only is it sufficiently easy to carry out, solid matter can be easily removed, and the necessary reaction time for producing optically anisotropic pitch can be shortened compared to conventional methods. Furthermore, the optically anisotropic pinch produced using the raw material of the present invention contains an optically anisotropic phase of 90 to 100 volume, is substantially homogeneous, and has an extremely low softening point. Has excellent properties.

Therefore, complicated and costly steps such as high-temperature filtration of infusible materials, solvent extraction, and catalyst removal, which are required in conventional methods, are not required. Regarding melt-spinning of carbon fibers, the spinning temperature (the highest temperature that must be applied to the pitch during the second step of spinning) can be within the range of about 290'C to about 360'C, so that the cracked gas can be reduced. It is easy to control the temperature and is free from troubles such as occurrences.
Industrial aspects of the present invention include the fact that the yarn thickness is uniform, high performance yarn can be easily spun without yarn breakage, and there is little energy loss during heating. The effect from this is enormous.

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

Example 1 As a raw material of the present invention, an initial boiling point of 204°C 125% by weight
Distillation point is 400@C, 70% by weight distillation point is 450°C,
90]i amount*distillation point 510'C<? :-Rera temperature is the normal pressure equivalent value of the distillation temperature measured in vacuum distillation operation), and the aromatic carbon fraction fa of the distillate at 400'C is catalytic cracking with an aromatic carbon fraction fa of 0.43. The equipment residue oil was used without distillation.

Put 400:'/'4 of this raw material into a 500ml stainless steel reaction vessel! Thermal decomposition polycondensation reaction was carried out at 11.430'C for 2 hours. During the reaction, nitrogen gas was passed through the surface of the liquid phase at 2 no/min as an inert gas, and the mixture was thoroughly stirred with a stirring blade. The pitch remaining in the container after the reaction is hereinafter referred to as βRP, and among this pRP, those with an optically anisotropic phase content (hereinafter referred to as AP%) of 1O volume or more are 50
m/ was placed in a glass beaker and allowed to stand at about 380°C for 2 hours in a nitrogen gas atmosphere at about 380°C to separate the optically anisotropic phase, which was then cooled to room temperature and solidified. Next, the glass beaker was broken and separated into an upper layer containing a large amount of optically isotropic phase and a lower layer containing a large amount of optically anisotropic phase.

The AP% of the optically anisotropic phase in the lower layer is 100°C, the softening point is 268°C, and the contents of rob, rAJ, "B", and "C" are 11.7 times Jl-ch and 28 times, respectively. .6% by weight
, 25.2% by weight, and 34.5% by weight. The optically anisotropic pitch lO plum obtained in this way was filled into a small spinning machine, and heated to about 100 mm H with nitrogen gas.
g, extruded through a nozzle with a diameter of 0.3 mm, and wound up with a bobbin provided at the bottom at a linear speed of 600 m/min.

In the spinning temperature range of about 330'C to about 370'C, we searched for the temperature with the minimum yarn breakage frequency and evaluated the yarn breakage frequency at - that temperature.For comparison, a similar experiment was carried out using the present raw material. 40
The results were also compared for the cases in which the residual tar distilled to 0°C was used as the raw material and the case in which the residual tar distilled to 450'C was used as the raw material, and the winner was compared. However, in the comparative experiment, the time for the thermal decomposition polycondensation reaction was set to 2.5 hours for the former.

Tables 1 and 2 show the comparison results. As is clear from these tables, when the raw materials of the present invention are used, an optically anisotropic pitch with a low content of the C component, which is an insoluble component, can be obtained. The softening point of the pitch was low and the frequency of thread breakage was reduced, which was extremely good.

Example 2 As the raw material of the present invention, the initial boiling point is 204@C.

35 [1 distillation point is 400'C, 90% by weight distillation point is 53
4°C (these temperatures are normal pressure equivalent values as in Example 1), and the aromatic carbon fraction fa of the distillate at 400°C is 0.56. As shown in Table 4, the pitch obtained in the same manner as in Example 1 except that catalytic cracker residual oil was used had an optically anisotropic phase of 100 chi (AP in the table).
100) and a low softening point, and the spinning properties of the carbonaceous pitch were also extremely excellent.

Example 3 As a raw material of the present invention, an initial boiling point of 204 ° C 11B weight %
Distillation point is 400”C, 90% by weight distillation point is 52.7°C
(These temperatures are normal pressure equivalent values as in Example 1), and the aromatic carbon fraction fa of the distillate at 400'C is 0.57, a catalytic cracker residue. An optically anisotropic pitch was obtained in the same manner as in Example 1 except that oil was used.

Margin below (30) As is clear from the results in Table 6, the feedstock oil of the present invention containing a hydrocarbon fraction below 400°C has an optically anisotropic phase of 100% due to the thermal decomposition polycondensation reaction. It is possible to provide a carbonaceous pitch with a low softening point, and the spinning properties of the carbonaceous pitch are also significantly superior compared to the case of using feedstock oil from which hydrocarbon fractions below 400°C have been removed. It is something that

Applicant: Toa Fuel Industry Co., Ltd. Agent Patent Attorney: Kiyoshi Kiyoshi (33) Commissioner of the Patent Office Kazuo Wakasugi1, □Xiang 1981 4I Seiqin No. 078430 No. 2, Title of Invention Manufacturing method and manufacturing method [Maker No. 3, Relationship with the case of the person making the amendment Patent company Akebono, 91ge Hitopashi address Kujira 1 Tsukuda-ku - Shizaku 1-11-shi? ) tyljII? ff1-12 name
Toa Fuel Industry City μ Company 4, Agent 2) Column 4, ``Yield of optically anisotropic layer m'' is changed to [
The yield of the optically anisotropic phase in the lower layer is corrected.

Claims (1)

Scope of Claims (11) The residual oil from the catalytic cracking unit has an aromatic carbon fraction fa of Q, 4 or more, about 200@C or more, and about 400@C
Optically anisotropic pitch, characterized in that it contains a hydrocarbon fraction or a mixture thereof having a boiling point of:
Raw materials for manufacturing. (21 Raw material for producing optically anisotropic pitch according to claim (1), characterized in that the aromatic carbon fraction fa is 0.5 or more. (3) Contains The content of the hydrocarbon fraction is about 1
5% by weight - about 50% by weight of the raw material for producing optically anisotropic pitch according to claim 11 or Q) (4) The carbonization The initial boiling point of the residual oil feedstock of the catalytic cracking unit containing hydrogen fraction is approximately 200@C, 15 to 401 ffi, and the distillation point is approximately 40
0''C, 90% by weight distillation point is about 5400C or less (claims 11 to 0)
A raw material for producing the optically anisotropic pitch according to any one of the above. (5) the aromatic carbon fraction fa is 0.4 or more,
It is characterized by carrying out a thermal decomposition polycondensation reaction using the residual oil of the catalytic cracker 9 containing a hydrocarbon fraction having a boiling point of about 400"C or less at a temperature of about 200°C or higher and a mixture thereof as a raw material. (6) A method for producing an optically anisotropic pitch according to claim 1, wherein the aromatic carbon fraction fa is 0.5 or more. Manufacturing method. (7) The content of the hydrocarbon fraction to be contained is approximately 1
The method for producing optically anisotropic pitch according to claim 6) or claim (i), characterized in that the amount of the optically anisotropic pitch is from 5% by weight to about 50% by weight. (8) The initial distillation of the residual oil feedstock of the catalytic cracker containing the hydrocarbon fraction is about 200'C, 15-40 M I
t % distillation point is about 400'C and 90311% distillation point is about 540'C or less, according to any one of claims (5) to (7). , a method for producing optically anisotropic pitch. (9) The temperature of the thermal decomposition polycondensation reaction is about 380@C'?
'The method for producing an optically anisotropic pitch according to any one of claims β) to (8). (10 The temperature of the thermal decomposition polycondensation reaction is from about 3806C to about 46C.
The method for manufacturing an optically anisotropic pinch according to any one of claims 6) to S), characterized in that the temperature is in the range of 0°C. (11) The temperature of the thermal decomposition polycondensation reaction is about 410'C to about 4
A method for producing an optically anisotropic pitch according to claims (5) to (10), characterized in that the pitch is in the range of 40e'C. (12) The pyrolytic polycondensation reaction is carried out until the optically anisotropic pitch portion in the polycondensate produced by the pyrolytic polycondensation reaction reaches a content of about 20 body parts to about 80 volume parts. After that, the polycondensate is kept at about 400@C or less and allowed to stand still, thereby causing the optically anisotropic pitch to settle and accumulate in the lower layer of the reaction tank, and the non-optical pitch in the upper layer of the reaction tank. Claims (5) to (11) characterized in that the anisotropic phase is separated and taken out from the portion in which it occupies the majority.
) The method for producing an optically anisotropic pitch according to any one of the above items. (13) The optically anisotropic pitch according to claim (12), characterized in that the polycondensate is kept at a temperature range of about 3506 C to about 400 @ C and allowed to stand substantially still. manufacturing method. (14) The optical difference according to claim (12), characterized in that the polycondensate is kept at a temperature range of about 60° C. to about 390° C. and allowed to stand substantially still. Method of manufacturing directional pitch. (15) The upper part of the reaction tank is used as the reaction zone for the pyrolysis polycondensation reaction, and the lower part of the reaction tank is used as a substantial standing area for allowing the optically anisotropic pitch to settle and accumulate in the lower layer.From the top of the reaction tank The optical system according to any one of claims (5) to (8), characterized in that the raw material is continuously injected and the generated optically anisotropic pitch is continuously extracted from below. Method of manufacturing anisotropic pitch.