JPS6030365B2 - Method for producing high strength, high modulus carbon fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides high strength,
The present invention relates to a method for producing high modulus carbon fiber.

More specifically, highly aromatic coal or petroleum pitch is hydrogenated in a hydrocarbon solvent in the presence of a hydrogenation catalyst, and the hydrogenated pitch from which the catalyst, insoluble solids, and hydrocarbon solvent have been removed is heated at a high temperature. The mesophase-containing pitch (hereinafter referred to as mesophase pitch) obtained by heat treatment under reduced pressure for a short time is melt-spun, infusible in air, carbonized in an inert gas atmosphere, and further processed as necessary. The present invention relates to a method for producing high-strength, high-modulus carbon fiber, which is characterized by subjecting it to graphitization treatment. Carbon fiber has two advantages in terms of its mechanical strength:
It can be classified as carbon fiber.

GP carbon fiber has a strength and elastic modulus of 70 to 140 k9/h and 3 to 5 t, and is produced mainly from optically isotropic fibers. G.P.
The main uses of carbon fiber are abrasion materials, heat insulation materials, antistatic materials, filter materials, filters, and packing. These are materials that utilize the properties of carbon in the form of fibers.
Most cases do not require carbon fiber with high strength and modulus. On the other hand, HP carbon fiber is 200-35
It has high strength and elastic modulus of 0k9/m2 and 10-4/m2, and is mainly manufactured from polyacrylonitrile as raw material.

The main use of HP carbon fiber is as a composite material in combination with resin etc. This HP carbon fiber composite material has significantly superior strength and elastic modulus per unit weight compared to other industrial materials, so it is used in special materials such as rockets and aircraft, and leisure goods such as golf clubs, tennis rackets, and fishing rods. It is predicted that demand will increase significantly as a material for automobiles and general buildings. However, HP carbon fiber made from polyacrylonitrile is very expensive, so HP
Although carbon fiber composite materials have excellent mechanical strength, they are expensive and have rarely been used as general industrial materials.

Therefore, it is desired to develop a method for producing HP carbon fibers at low cost. One of the methods for producing inexpensive HP carbon fibers has been proposed using mesoface pitch obtained by heat-treating inexpensive pitches as a raw material.

(For example, Special Publication No. 49-8-4, Special Publication No. 753
(Refer to Japanese Patent Publication No. 3, Japanese Patent Publication No. 54-181, Samurai Seki No. 54-155625, and Japanese Patent Publication No. 1133/1999) According to these methods, the pitches are relatively low, around 400q○. After heat treatment at a heat treatment temperature for several hours to several tens of hours, the resulting mesoface pitch containing 40 to 10 t% of mesoface is melt-spun, and the raw material fiber with mesoface oriented in the fiber axis direction is infusible in air. , by carbonizing and graphitizing in an inert gas atmosphere, HP
It is said that carbon fiber can be obtained. However, in the conventional method described above, as a method for manufacturing mesoface pitch, a heat treatment method is adopted in which pitches are heat treated for several hours to several tens of hours to promote polycondensation of pitch, so that mesoface pitch is produced in the early stage of heat treatment. The degree of condensation of mesophases is higher than that of mesophases generated in the later stages of heat treatment, and as a result, there is a distribution in the degree of condensation of mesophases.
The uniform meltability of the mesoface pitch is reduced, and ultimately the spinnability of the mesoface pitch is reduced.

In addition, when the heat treatment temperature is 430 qC or more, the military condensation of mesophase generated at the beginning of the heat treatment is now significantly accelerated, and the degree of condensation reaches such a level that it can no longer be melted, so the mesophase pitch obtained is It is necessary to remove the above-mentioned mesophases that have become insoluble. Therefore, the conventional method for producing mesobase pitch is not the best method for producing HP carbon fiber raw material.

As a result of extensive research into the production method of mesoface pitch, which can be used as a raw material for HP carbon fiber, the present inventors have developed a new production method for mesoface pitch that has excellent paperability and can also produce HP carbon fiber. The present invention was completed.

That is, the present invention uses pitches with an aromatic index of 0.6 or more,
Hydrogenation in a hydrocarbon solvent in the presence of a hydrogenation catalyst,
After producing hydrogenated pitch, which has a hydrogen content 10% or more higher than that of the raw pitch and at least 9% of which is composed of components with a molecular weight in the range of 400 to 600, the catalyst, non-fallible solids, and solvent are extracted from the hydrogenated pitch. is removed and heat treated under reduced pressure to produce mesophase pitch containing mesophase of lwt% or more and less than 4wt%, which is then melt-spun, infusible in air, and further carbonized in an inert atmosphere. The present invention provides a method for producing high-strength, high-modulus carbon fiber, which is characterized in that it is graphitized if necessary. As described above, the present invention has major features in the method for producing mesophase pitch raw materials and the method for producing mesophase, and the mesophase content of mesophase pitch is significantly lower than in conventional methods.

Here, the mesophase content in the present invention is defined as JIS
- Refers to the quinoline-insoluble content of K-2425. In the present invention, the raw materials for mesoface pitch are coal depolymerized products,
Coal tar or a highly aromatic pitch such as coal tar pitch or ethylene bottom oil pitch is used. here,
The term "coal depolymerized product" refers to a pitch-like material obtained by depolymerizing coal in a hydrocarbon solvent under hydrogen pressure and removing undissolved residual bamboo and the solvent. These highly aromatic pitches are hydrogenated in a hydrocarbon solvent in the presence of a hydrogenation catalyst. In the case of the present invention, the pitch need not simply be subjected to hydrogenation treatment. That is, hydrogenation conditions and catalysts are selected that can improve the degree of hydrogenation of pitch and at the same time suppress its polycondensation. Moreover, the hydrogenation conditions can be selected so as to obtain hydrogenated pitch that has a hydrogen content 10% or more higher than that of the raw material pitch, and at least 9 t% of which is composed of components having a molecular weight of 400 to 600. is necessary. The catalyst, insoluble solids derived from raw materials, and hydrocarbon solvents are removed from the solution containing hydrogenated pitch obtained by the above hydrogenation treatment to produce hydrogenated pitch. In addition, insoluble solids in the raw material can also be removed by heat-melting sieving, centrifugation, solvent extraction, etc. prior to the above-mentioned hydrogenation treatment. The hydrogenated pitch thus obtained is then heated at a high temperature and under reduced pressure for a short period of time, e.g.
A mesoface pitch containing less than 1 wt % of mesoface is produced by heat treatment at a pressure of 30 or more and a pressure of 4 or less and less than 3 whiskers.

In the present invention, since mesophase is generated at high temperature, in a short time, and under reduced pressure, the time lag in mesophase generation can be reduced, and as a result, mesophase with a very uniform degree of condensation can be generated. Moreover, the optically isotropic components in the hydrogenated pitch, which are difficult to convert to mesophase and cannot be uniformly melted with mesophase, can be removed as distillate oil, so the mesophase pitch obtained is It can be melted uniformly and has excellent spinnability.

Furthermore, in the case of the present invention, the mesoface content in the mesoface pitch can be significantly lower than the 40 to 10 skin t% of the conventional method, which also greatly contributes to improving the gradeability of the mesoface pitch. The mesoface pitch obtained by the above treatment is melt-spun, infusible in air, and then
By carbonizing in an inert gas atmosphere and graphitizing as necessary, it has a strength of 200K9/1 or more and a strength of 1
It is possible to produce HP carbon fibers with an elastic modulus greater than or equal to . Therefore, by implementing the present invention, it is possible to
Moreover, mesoface pitch, which can be used as a raw material for high-strength, high-elasticity HP carbon fiber, can be produced from inexpensive pitches without using special solvents, chemicals, or methods.

Pitches with high aromaticity are used as raw materials for the present invention.

For example, coal-based coal depolymerized products, coal tar, coal tar pitch, and petroleum-based ethylene bottom oil pitch are preferred. In addition, aliphatic-rich petroleum car oil is heat treated at a temperature of 3.
50 to 45,000 and a heat treatment time of 156 to 1q to remove insoluble solids and increase the aromaticity of the pitch. Therefore, the aromatic index of pitch suitable for the raw material of the present invention is 0.6 or more. Here, the aromatic index is set by Takeya et al. (Journal of Japan Fuel Association, Vol. 46, 92
(Page 7, 1967) refers to the value according to the following formula. Aromatic index = CZH-HQ'x-Ho'yC/day, where C is the number of all carbons, day is the number of all hydrogens, HQ is the number of hydrogens at the Q position, and Ho is the number of hydrogens at the 8th position and above. means number.

Further, x=y=2. Pitch with an aromatic index of less than 0.6 results in a low yield of mesoface pitch and a decrease in uniform melting properties of mesoface pitch. HP, the final product
This is not preferable because it reduces the strength of the carbon fiber. A raw material having the above properties is hydrogenated in a hydrocarbon solvent in the presence of a hydrogenation catalyst. The hydrocarbon solvent used in the present invention is not particularly limited, and any solvent may be used as long as it can substantially dissolve the above-mentioned raw materials.

For example, coal-based military oil absorption oil, creosote oil,
Highly aromatic solvents such as tar oil, anthracene oil, the vertical fraction of ethylene bottom oil, which is a petroleum-based virgin oil, and the light fraction of FCC cracked oil, are preferred. However, aliphatic-rich solvents are not preferred because they cannot sufficiently dissolve the raw materials of the present invention and the subsequent hydrogenation treatment cannot be carried out smoothly. Further, the raw material/hydrocarbon solvent ratio (weight basis) is set to 1:2 or more, preferably 1:3 to 1:10.

When the raw material/solvent ratio is less than 1:2, a great deal of effort is required to separate and remove the catalyst and non-falling solids after the hydrogenation treatment.
Pitch dissolved in a highly aromatic hydrocarbon solvent is hydrogenated in the presence of a hydrogenation catalyst. In the present invention, the pitch need not simply be subjected to hydrogenation treatment. That is, the hydrogenation of the pitch is sufficiently promoted, the polycondensation of the pitch hardly progresses, and the hydrogen content of the obtained hydrogenated pitch is 10% lower than that of the raw material pitch.
above, preferably 15 to 50%, and at least 9 skin t% of the hydrogenated pitch produced is 400 to 6
The hydrogenation conditions and hydrogenation catalyst are selected to have a molecular weight in the range of 0.00. Here, the molecular weight of hydrogenated pitch means the molecular weight measured by gel permination chromatography using quinoline as a carrier dropper. Mesoface pitch obtained from hydrogenated pitch that does not satisfy all of the above properties by hydrogenation under conditions other than the above is difficult to melt uniformly, and not only does it have poor gradeability, but also has a high carbon content in the final product. Fiber strength decreases.

Of course, the raw material pitch can be hydrogenated. However, the mesoface pitch obtained by heat treatment according to the method of the present invention does not melt uniformly and has no gradeability at all. Therefore,
Hydrotreating is an essential element in the present invention.
The hydrogenation conditions in the present invention include a hydrogenation temperature of 400-
50,000 ℃, the holding time at that temperature is 240 minutes or less, the hydrogen pressure is 50 to 300 k9/G, preferably 430 to 480 qo, for 5 to 60 minutes, 70 to 2
Set to 00k9/earth/G. In the case of the present invention, hydrogenation conditions are preferably high temperature and short time, which improves the weavability of mesoface pitch, which will be described later. Hydrogenation temperature is 400q
If the hydrogen pressure is less than 50k9/G, the hydrogenation of the raw material pitch will not proceed sufficiently, making it difficult to obtain hydrogenated pitch with properties suitable for the raw material of the present invention. On the other hand, when the hydrogenation temperature exceeds 500°C and the holding time exceeds 24°C, the polycondensation reaction of the raw pitches progresses, making it impossible to obtain hydrogenated pitch with the properties required by the present invention. Furthermore, it is difficult to uniformly melt the mesophase pitch obtained using this as a raw material. Also, when the hydrogen pressure exceeds 300kg/c/G, the hydrogenated pitch obtained is less than 300kg/c/G.
It is not particularly good as a raw material for mesoface pitch. Further, the hydrogenation catalyst used in the present invention includes iron, cobalt, molybdenum, copper, tungsten, nickel, platinum,
At least one selected from the group of rhodium, oxides and sulfides of the metal is preferred.

The hydrogenation catalyst is added in an amount of 1 to 2 t%, preferably 2 to 1 t%, based on the raw material pitch.

If the amount of catalyst added is less than 1 wt%, the hydrogenation treatment will take a long time, and if the amount exceeds 2 t%, the effect of the catalyst will not be particularly large. A solution containing hydrogenated pitch that has been hydrogenated under the above conditions is filtered or centrifuged to remove the hydrogenation catalyst and insoluble solids inherent in the raw material, and then a hydrocarbon solvent is removed, for example. Removal by vacuum distillation yields hydrogenated pitch suitable for the present invention.

The solvent removal conditions are not particularly limited, and
Although it is not necessary to remove all of the hydrocarbon solvent used, in order to confirm that the resulting hydrogenated pitch has the properties described above, the distillation conditions were changed to a bottom temperature of 200%.
It can be set to ~300qo, 5 to 2 days a day. Next, the hydrogenated pitch is heat treated at high temperature for a short period of time under reduced pressure to reduce mesophase to 1 to 40 wt%, preferably 5 to 40 wt%.
A mesophespitz containing 3 skin t% is produced.

The heat treatment method at a high temperature, for a short time, and under reduced pressure is an essential element for the present invention, like the above-mentioned hydrogenation treatment, and it is no exaggeration to say that the present invention was completed by combining the above two steps. That is, since the heat treatment in the present invention is carried out at high temperature, for a short time, and under reduced pressure, mesophases are generated intensively in a very narrow time range, and as a result, the degree of condensation of mesophases is extremely uniform.

In addition, components in the hydrogenated pitch that are difficult to convert to mesophase and cannot be uniformly melted with mesophase can be removed as crabmeat oil. Therefore, the mesoface pitch produced by the method of the present invention melts uniformly and has excellent spinnability. On the other hand, the conventional manufacturing method for mesophase pitch, in which pitch is heat treated at a relatively low heat treatment temperature of about 400 qo for about 4 to 5 hours to slowly generate mesoface, employs a long heat treatment method. The degree of condensation of mesophase cannot be made uniform, and as a result, the uniform meltability of mesophase pitch has been impaired.

However, as a method to improve the drawbacks of the above conventional methods, there is a method of bubbling an inert gas into the pitch or reducing the pressure during heat treatment of the pitch (Hakama Kaisho 54-11
No. 33) has been proposed. The purpose of the bubbling method is to bubble an inert gas into the pitch during heat treatment to facilitate the removal of components in the pitch that are difficult to convert into mesophase.

However, the degree of removal of components that are difficult to convert into mesophase in pitch by this method is not sufficiently high, and it has not been possible to shorten the heat treatment time to the extent that the degree of condensation of the mesophase produced is uniform. Yes, no,
. On the other hand, the reduced-pressure heat treatment method is also used in the same way as the bubbling method, with the purpose of removing components in the pitch that are difficult to convert into mesophase.

According to this method, the pitch is heated at a heat treatment temperature of 500°C or less,
Holding time at that temperature is 5 minutes or less, 100 days ab
It is heat-treated at less than s and converted into mesophase pitch.
However, since this method requires a temperature increase process of 30° C./hour or less, the actual heat treatment time becomes significantly longer. In contrast, in the case of the present invention, only 1 to 2 minutes is required to raise the temperature to a predetermined heat treatment temperature, and the present invention is fundamentally different from the reduced pressure heat treatment method. Next, in the reduced pressure heat treatment method, mesoface pitch that is uniformly melted and has paperability cannot be obtained at a heat treatment temperature of more than 500°C. However, in the case of the present invention, which is made from hydrogenated pitch that has undergone hydrogenation treatment under special conditions and has special properties, it can be melted uniformly even when the heat treatment temperature exceeds 500°C, and maintains its fibrous properties. It is possible to manufacture a mesoface pitch with
The spinnability of mesoface pitch improves as the heat treatment temperature becomes higher and the heat treatment time becomes shorter. In addition, pitches without any treatment are 430 to 5000
In the case of heat treatment at a heat treatment temperature of 0, the formation of insoluble and infusible mesophase cannot be avoided, and the obtained mesophase pitch is formed by forming the above-mentioned insoluble and infusible mesophase before spinning. must be passed and removed. However, since the mesophase pitch obtained by the method of the present invention contains almost no unmelted or infusible mesophase, there is no need for sieving. From the above, it is easy to see that the present invention is fundamentally different from the reduced pressure heat treatment method and that the present invention is superior to the reduced pressure heat treatment method.

Therefore, it can be said that the mesophems generation method of the present invention is very superior to the subordinate method and is a novel method. The heat treatment conditions in the present invention are set so that the mesoface content of the mesoface pitch is 1 to 4%, but usually the heat treatment temperature is 480oC or higher and the holding time at that temperature is 3mm or less. The pressure is lower than 4 ft/day, preferably 500 to 550 qo and 2 to 18 qo, respectively.
Minutes, 3 to 2 ship days ABS should be set.

If the mesoface content is less than 1wt%, HP carbon fiber cannot be produced using the mesoface pitch as a raw material, and if it exceeds 4 fins%, the compatibility of the mesoface pitch is significantly reduced. In addition, if the heat treatment temperature is less than 10 mm, the holding time at that temperature exceeds 3 pieces, and the pressure exceeds 40 mm, the mesoface pitch can be melted uniformly and has excellent spinnability. This is not desirable because it is not possible to obtain The mesoface pitch obtained by the heat treatment as described above shows that 6 t% or more of it is optically anisotropic under an optical microscope.

A mesoface pitch containing 1 to 4 t% of mesoface is then melt-spun.

The mesophase pitch of the present invention can be spun in a temperature range of 320 to 40 mm, and its spinnability is excellent to the same degree as the optically isotropic pitch that is the raw material for GP carbon fiber. Furthermore, the uniformity of the obtained raw material fiber diameter in the fiber axial direction is very excellent, which shows how excellent the meltability of the mesoface pitch of the present invention is. Although less than 40% of the mesoface pitch of the present invention is optically isotropic, this mesoface pitch can be uniformly melted, and the mesoface is oriented in the fiber ball direction during spinning, and this orientation is Inherited by carbon fiber and graphite fiber.

The obtained raw material fiber has an infusibility temperature of 260 to 340 in air.
00, the infusibility time is 60 minutes or less, and the temperature increase rate is 3.3 qo/min or less, preferably 270 to 32, 0, 5 to 3 qo/min, and 0.5 to 2.0 qo/min, respectively.

If the infusibility temperature is less than 260° C., the infusibility of the raw material fibers will not proceed sufficiently, and during carbonization following infusibility, melting or fusion of the fibers will be observed, making it impossible to obtain HP carbon fibers. When the infusibility temperature exceeds the milk OQ and the infusibility time exceeds 60 minutes, the fiber is
The carbon fiber becomes prone, and the strength of the final carbon fiber decreases. The infusible fibers are heated in an inert gas atmosphere at a carbonization temperature of 800 oo or more and for a holding time of 5 minutes or more at that temperature.
The temperature increase rate is 7°C/min or less, preferably 1000 to 1
Carbonize at 500 qo, 10-30 minutes, 2-5°C/min.

If the carbonization temperature is 800 qo or less and the carbonization time is less than 5 minutes, the carbonization of the fibers will not proceed sufficiently, making it impossible to obtain carbon fibers with high strength. When the temperature increase rate exceeds 7° C./min, fusion is observed in some of the obtained carbon fibers, and the strength of the carbon fibers decreases. Furthermore, when improving the elastic modulus of carbon fibers, the fibers are heated to 2000 to 30% in an inert gas atmosphere.
Graphitize at 0pi0. The carbon fibers obtained by the above treatment (including fibers subjected to graphitization treatment) have a carbon fiber density of 20 to 3
The carbon fiber of the present invention has a strength and elastic modulus of 50k9/h and 10~4"/fence, and the carbon fiber of the present invention is inferior to polyacrylonitrile-based HP carbon fiber in both appearance and mechanical strength. do not have.

The present invention will be explained in more detail based on embodiments.

Hydrogenation catalysts such as iron oxide are used as IM% for pitches.
Above, preferably 2 to 1 skin t%, add at least twice the amount of hydrocarbon solvent, preferably 3 to 1 volume, and after thorough mixing and dissolution, raise the temperature to 400 to 500°C and hold at that temperature. 240 minutes or less, hydrogen pressure 50k9/g or more, preferably 430 to 480 minutes, 5 to 60 minutes, respectively.
Hydrogenate under the conditions of 70 to 200k9/Ga. The solution containing hydrogenated pitch and hydrogenation catalyst obtained after completion of hydrogenation is passed through a filter to remove solids derived from the catalyst and raw material pitch, and the solution is distilled under reduced pressure to remove hydrocarbons. Collect solvent. Bottom temperature of vacuum distillation is 200~
The solvent can be recovered by heating at 300qC for 5 to 2 days. The hydrogen content of the obtained hydrogenated pitch is 10% or more higher than the hydrogen content of the raw material pitch, and 9% or more of the hydrogenated pitch has a molecular weight in the range of 400 to 600. Pitches with the above properties are heat treated at a temperature of 48,000 or higher and held at that temperature for 3.
0 minutes or less, pressure 40 days ABS or less, preferably 500-550oC, 2-18 minutes, 3-2 days ABS
A mesoface pitch containing 1 to 4 w% of mesoface, preferably 5 to 3 t% of mesoface is produced by heat treatment under conditions of BS.

After the mesophase pitch is graded at 320 to 400 qo, it is heated in air at an infusibility temperature of 260 to 34,000, a holding time at that temperature of 6 min or less, and a heating rate of 3.3°C/min or less, preferably, 270~320oo each, 5~30 minutes,
It becomes infusible at a rate of 0.5 to 2.000/min.

The infusible fibers are heated to a carbonization temperature of 8 in an inert gas atmosphere.
00°C or higher, holding time at that temperature for 5 minutes or more, heating rate 7°C/min or less, preferably 1000 to 150°C, respectively.
Carbonize at 0q○, 10-30 minutes, 2-5℃/min, and
Graphitize at 2,000 to 300,000 in an inert gas atmosphere. The carbon fibers obtained by the above treatment (including fibers subjected to graphitization treatment) have a weight of 200 to 350 k9/
It has a high strength and elastic modulus of 10 to 4"/mm, and by carrying out the present invention, it can be easily obtained from pitches that are inexpensive and easily available, and can be easily obtained without using any special solvents or chemicals. HP carbon fibers can be produced without using any of the following methods.The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited thereto.

Example 1 Coal tar pitch ground to 112 mesh or less (chemical composition according to JIS-M Mottling 13, C: 91.
Insects Wt%, H: 4.6%, N: 0.97wt%, S
:1.09Wt%, 0:1.83%, aromaticity index 0
．． 95), 5 M% of iron oxide catalyst and 3 times the amount of absorption oil were added, and after thorough mixing, the hydrogenation temperature was set at 460°C.
Holding time at that temperature is 1 minute, hydrogen pressure is 100k9
After hydrogenation with 100% carbon dioxide gas, the immovable solids and catalyst from the coal tar pitch were removed with a filter, and the liquid was distilled with a bottom temperature of 250 oo for 1 day using a 100% abS to remove the hydrogenated pitch. Obtained.

The chemical composition of this hydrogenated pitch is C: 91.97wt%,
H: 5.61M%, N: 0. Spot Wt%, S: 0.41w
t%, 0:1.13%, and the hydrogen content was approximately 20% higher than that of the raw material coal tar pitch. In addition, as a result of measuring the molecular weight distribution by gel permeation chromatography using quinoline as a solvent, 91 wt% of hydrogenated pitch has a molecular weight of 400 to 600.
It was found that it exists in the range of Next, the hydrogenated pitch was immersed in a heated and molten salt solution to 510 q0, and then the pressure was immediately reduced and held for 10 minutes.

The pressure was set at 1 ft/day. The mesoface content of the obtained mesoface pitch was 27.6 wt%.
After melt-drawing this mesoface pitch at a spinning temperature of 350 qo and a winding speed of 800 m/min, the temperature was raised in air to 28 qo at a rate of 1.0 qo/min, and the temperature was maintained at that temperature for 5 minutes. It was retained and made infusible.

Infusible fibers can be heated up to 100,000 5 in an argon gas atmosphere.
The temperature was raised at a heating rate of 0.degree. C./min, and the temperature was maintained for each strip to produce carbon fibers. The yield of carbon fiber was 88.9 wt% based on the raw material fiber. The average diameter of carbon fiber is 12
．． 8. The strength was 235k9/fence, and the elastic modulus was 16.2/fence. Example 2 Example 1 except that the hydrogenated pitch obtained in Example 1 was heat treated at a temperature of 520°C and the holding time at that temperature was 5 minutes.
A mesoface pitch was produced by heat treatment in the same manner as above.

Mesoface content in Mesoface Pitch is 17.65
It was wt%. Mesoface pitch was made into paper yarn at a paper yarn temperature of 35 pi and a winding speed of 1000 m/min to obtain a raw material fiber. This raw material fiber was treated in the same manner as in Example 1 to produce carbon fiber. The yield of carbon fiber is based on the raw material fiber.
It was 2wt%. The average diameter of carbon fiber is 11.21,
Strength is 2 spots K9/fence, elastic modulus is 14. It was boiled.

Example 3 The hydrogenated pitch obtained in Example 1 was heat-treated at a temperature of 5300
0. Mesoface pitch was formed by heat treatment in the same manner as in Example 1 except that the holding time at that temperature was changed to 4 minutes.

The mesoface content of mesoface pitch is 11. Sakaki T
%Met. Mesoface pitch Yabu thread temperature I 5 o'clock ○,
The fibers were spun at a winding speed of 1400 m/min to obtain raw fibers. This raw material fiber was treated in the same manner as in Example 1 to produce carbon fiber. The yield of carbon fiber is 89.4w based on raw material fiber.
It was t%. The average diameter of carbon fiber is 10.1 threads, the strength is 310K9/fence, and the elastic modulus is 17. It was boiled.

In addition, from the comparison of Examples 1 to 3, it was found that by increasing the heat treatment temperature and shortening the heat treatment time of hydrogenated pitch under reduced pressure,
It can be seen that the spinnability of mesoface pitch and the strength of carbon fiber, which can be evaluated by fiber diameter, winding speed, etc., are improved.

Example 4 The carbon fiber obtained in Example 3 was heated in an argon gas atmosphere.
The temperature was increased to 280,000 at a temperature increase rate of 1000/min, maintained at that temperature for 5 minutes, and graphitized.

The yield of graphite fiber was 85.8 wt% based on the raw material fiber. The average diameter of graphite fiber is 9.8mm, the strength is 210k9
/No, the elastic modulus was 38.5t/boiled.

Example 5 Australian lignite crushed to 60 mesh or less was heated for 60 minutes at 410 qo in 3 times the amount of oil in tar under a hydrogen pressure of 50 k9/g, to fully dissolve the solvent-soluble portion of the coal. , remove undissolved Zenizumi with a filter,
Distilled under reduced pressure to produce a coal depolymerized product.

The distillation conditions were a bottom temperature of 350° C. and 10 days of abs. The properties of the coal depolymerized product are chemical composition C: 89.27w
t%, H: 514wt%, N: 0.98wt%, S
:0. Milk wt%, 0:4.2 fence [%, aromatic fat number 0.8
It was 0. To this coal depolymerized product, 2 wt % of cobalt-molybdenum catalyst and 3 times the amount of vertical crab content of ethylene bottom oil were added, and after thorough mixing, the hydrogenation temperature was 450°C.
Holding time at that temperature 10 minutes, hydrogen pressure 150k
After hydrogenation at 9/Su・G and solid-liquid separation using a filter, the transferred liquid was distilled at a bottom temperature of 200° C. at 10 Yanagi-Hitata A-Hiro to obtain hydrogenated pitch.

The chemical composition of hydrogenated pitch is C: 89.41wt%, H:
6.24wt%, N: 1.04wt%, S: 0.28W
t%, 0:3.039%, and it was found that the hydrogen content was increased by about 21% compared to the hydrogen content of the depolymerized raw material coal. In addition, as a result of measuring the molecular weight distribution by gel permeation chromatography using quinoline as a solvent, it was found that 91 wt% of hydrogenated pitch has a molecular weight of 400.
It was found that it exists in the range of ~600. Next, the hydrogenated pitch was immersed in heated and molten salt at 520:00, the pressure was immediately reduced, and the temperature was maintained for 5 minutes.

The pressure was 1 day Ta a wide. The mesoface content of the obtained mesoface pitch was 7.1 wt%. After spinning this mesoface pitch into paper yarn at a spinning temperature of 33,500 and a winding speed of 1,400 m/min, the temperature was raised to 300°C in air at a heating rate of 20 o/min, and the temperature was maintained for 5 minutes to infusible. did.

Infusible fibers are heated at 5℃/up to 1000qo in an argon atmosphere.
The temperature was raised at a heating rate of 15 minutes, and maintained at that temperature for 15 minutes to produce carbon fibers. The yield of carbon fiber is 8 based on the raw material fiber.
It was 7.4 wt%. The average diameter of carbon fiber is 10.0
The strength of the mountain was 262k9/pine, and the elastic modulus was 21.2/fence.

Example 6 Ethylene bottom oil pitch from which the vertical content was removed (chemically refined C
:94.26M%, H:5.53Wt%, N:0.00
Wt%, S: 0.07wt%, 0:0.14wt%, aromatic index 0.76), 7wt% iron oxide catalyst, 3
After adding twice the amount of anthracene oil and mixing thoroughly, hydrogenation was carried out at a hydrogenation temperature of 470°C, holding time at that temperature for 5 minutes, and a hydrogen pressure of 100k9/su・G, followed by removing the catalyst and insoluble solids with a filter. Then, the liquid was distilled at a bottom temperature of 30 psi at a temperature of 1 yen to obtain hydrogenated pitch.

The chemical composition of this hydrogenated pitch is C: 92.8 t%, H
:6.91W%, N:0.05wt%, S:0.03w
t%, 0:0.1 is t%, and its hydrogen content is approximately 2% compared to the hydrogen content of ethylene bottom oil from which vertebrates have been removed.
It was found that there was an increase of 5%.

Moreover, as a result of measuring the molecular weight distribution by gel permination chromatography using quinoline as a solvent, it was found that 96 wt % of the hydrogenated pitch existed in a molecular weight range of 400 to 600. Next, hydrogenated pitch was added to 530
Immerse it in salt bath heated and molten to q0, immediately reduce the pressure,
It was held for 4 minutes.

The pressure was 1 day ABS. The mesoface content of the mesoface pitch was 131 wt%. This mesoface pitch was set at a shark thread temperature of 34 pm and a winding speed of 12 pm.
After spinning at a speed of 0.00/min, carbon fibers were manufactured in the same manner as in Example 1. The yield of carbon fiber was 89.6 wt%. The average diameter of carbon fiber is 11.4r, the strength is 23
9k9/fence, the elastic modulus was 14.2/fence. In most cases, the mesomorphs of the present invention are optically 100%
% contains an optically isotropic structure rather than an anisotropic structure.

All of the mesoface pitches in Examples 1 to 6 contain a part of optically isotropic structure, but all of the mesoface pitches can be melted uniformly, and the mesoface pitches are arranged in the fiber axis direction when forming paper yarns. Similarly, this orientation is inherited by carbon fibers.

As an example, the mesoface pitch (first
(Fig. 2), an optical micrograph of the raw material fiber (Fig. 2), and a scanning electron micrograph of the carbon fiber (Fig. 3). The mesoface pitch shown in Figure 1 contains approximately 10 to 15% optically isotropic structure, but the raw material fiber obtained by spinning this mesoface pitch is as shown in Figure 2. ,
It is oriented in the fiber axis direction. Furthermore, from FIG. 3, it can be seen that the orientation of the raw material fibers is inherited by the carbon fibers. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an optical micrograph of a mesoface pitch, FIG. 2 is an optical micrograph of a raw material fiber, and FIG. 3 is a scanning electron micrograph of a carbon fiber.

Tagi sardine Tafuse Ta 312

Claims (1)

[Claims] 1. Pitches having an aromatic index of 0.6 or more are hydrogenated in a hydrocarbon solvent in the presence of a hydrogenation catalyst so that the hydrogen content is 10% or more higher than that of the raw material pitch, and After producing a hydrogenated pitch, at least 90 wt% of which consists of components with a molecular weight in the range of 400 to 600, the catalyst, insoluble solids and solvent are removed and heat treated under reduced pressure to produce 1 wt.
% or more and less than 40 wt% of mesophase pitch, which is then melt-spun and then infusible in air, further carbonized in an inert atmosphere, and optionally graphitized. A method for producing high strength, high modulus carbon fiber. 2. Claim 1, wherein the hydrogenation catalyst is at least one selected from iron, cobalt, molybdenum, copper, tungsten, nickel, platinum, rhodium, and oxides or sulfides of these metals. the method of. 3. The method according to claim 1 or 2, in which the hydrogenation catalyst is used in an amount of 1 to 20 wt% based on the raw material pitch. 4 Hydrogen pressure 50-300kg/cm^2G, temperature 40
The method according to claim 1, wherein the hydrogenation is carried out by holding the temperature at 0 to 500°C for not more than 240 minutes. 5 Temperature 480℃ at pressure 40mmHgabs or less
The method according to claim 1, wherein the heat treatment is carried out by holding the heat treatment for a period not exceeding 30 minutes.