KR102249296B1 - Method of feed stock for isotropic pitch - Google Patents

Abstract

The present invention is a manufacturing method of a raw material for isotropic pitch manufacturing, specifically, a manufacturing method that undergoes pretreatment and filtration using a raw material containing a specific physical property and a compound, and the manufactured raw material for manufacturing the isotropic pitch is a high strength, high elasticity carbon fiber. It can be used in the production of isotropic pitch having a high softening point for.

Description

Manufacturing method of raw material for isotropic pitch manufacturing {Method of feed stock for isotropic pitch}

The present invention is a method for producing a raw material for producing isotropic pitch, in which the content of a specific compound contained in the raw material and the ratio thereof satisfy very limiting conditions, and the raw material for producing the isotropic pitch prepared therefrom is suppressed to produce carbon sludge. It can be used to prepare an isotropic pitch having excellent physical properties and spinnability that is not easily converted into a mesophase state in high yield.

Petroleum-based heavy oil, residual oil, and coal coal tar have high carbonization yields and low prices, so they have been expected as raw materials for carbon materials. In particular, naphtha cracker bottom oil (NCB oil) has been attracted attention as a suitable material for carbon fiber due to its high degree of aromatization and low sulfur, nitrogen, metal impurities, and insoluble content. NCB oil may be manufactured with pitches of isotropic or anisotropic, depending on conditions during heat treatment, and carbon fibers produced from each pitch have different properties. In order to obtain high-strength carbon fiber, anisotropic pitch, which is mainly optically anisotropic, is used, and carbon fiber produced from amorphous isotropic pitch is relatively low in strength, so it is manufactured in the form of short filaments or staples. It is widely used for purposes such as carbon fiber, and has not been used for composite materials for structural materials.

Carbon fiber is light in weight compared to its relatively strong strength, so it can be used in various fields such as sports goods, aviation industry, and automobiles, so many studies are being conducted to obtain high strength and high elasticity carbon fiber. High-strength, high-elasticity carbon fibers are mainly manufactured by oxidation-stabilizing and carbonizing PAN-based copolymerized polymer fibers. In addition, although the pitch-based carbon fiber manufactured from anisotropic pitch has high strength and high elastic properties, the manufacturing process is cumbersome in order to obtain a desired strength or elasticity, and there is a problem in an increase in production cost accordingly. Accordingly, in recent years, studies on high strength and high elasticity isotropic pitch-based carbon fibers have been actively conducted.

In order to manufacture high-strength, highly elastic isotropic pitch-based carbon fibers, the composition of the isotropic pitch for carbon fiber production is very important. The fiber had a tensile strength of 1 GPa or less, so it could only be used as a general-purpose carbon fiber.

In addition, Japanese Patent No. 3695007 has an invention for producing an isotropic pitch using a catalyst or a range of a softening point that is too wide, and a description of the physical properties of the carbon fiber produced therefrom is not specific.

As described above, most of the conventional inventions use petroleum heavy oil, residual oil, coal tar or a mixture or oil thereof as a material for manufacturing isotropic pitch, and only pay attention to the manufacturing process.

Recognizing this problem, the present inventors analyzed the physical properties and composition from the initial raw material for the production of isotropic pitch for the production of isotropic pitch-based carbon fibers having high strength and high elasticity, and studied a suitable manufacturing method therefor. As a result, it has come to develop a method for manufacturing an isotropic pitch that is superior in physical properties and radioactivity than before.

Japanese Patent No. 33695007

An object of the present invention is to provide a method for producing a raw material for obtaining an isotropic pitch for producing an isotropic pitch-based carbon fiber excellent in physical properties. The above object can be achieved by the use of a raw material having a specific range of physical properties and a compound composition, and a production method suitable therefor.

The present invention relates to a method for preparing a raw material for producing isotropic pitch, and provides a method for preparing a raw material having specific physical properties and compound composition through pretreatment and filtration.

In the present invention, the pretreatment process includes heat treatment and fractionation of the raw material, and provides a manufacturing method for removing solid substances from the pretreated raw material through filtration.

In the present invention, for the production of a raw material for isotropic pitch production, a method using a raw material in which the atomic ratio of carbon and hydrogen, the degree of aromatization, the average molecular weight, the content of the compound contained, and the ratio thereof satisfy a specific range is provided.

The manufacturing method according to the present invention can provide a raw material for producing an isotropic pitch having characteristic physical properties and compound composition such as a specific range of molecular weight and degree of aromatization, and the isotropic pitch manufactured using this can provide a specific range of softening point, molecular weight, and excellent spinnability. It suppresses the generation of carbon sludge or mesophase, and maximizes the mechanical properties of the carbon fiber produced therefrom.

1 shows a composition of a raw material and a comparison of a representative composition of a raw material prepared therefrom.
FIG. 2 shows a comparison of the composition of a compound containing one aromatic ring among raw materials and a compound containing one aromatic ring among raw materials prepared therefrom.
3 shows a composition comparison of a compound including two aromatic rings among raw materials and a compound including two aromatic rings among raw materials prepared therefrom.

Terms that are not separately defined in the description of the present invention may be understood to be suitable for those of ordinary skill in the field to which the present invention belongs to understand the contents of the present invention, and will obscure the subject matter of the present invention in the description and the accompanying drawings. It may not be described separately for the contents of the notices that may be made.

In the present invention, a method of preparing a raw material for producing isotropic pitch is as follows.

(a) heat-treating and fractionating a raw material containing at least one of petroleum-based heavy oil, naphtha cracking residual oil, or coal tar fraction to pretreatment; And

(b) filtering the raw material pretreated in (a);

It is a method for producing a raw material for isotropic pitch production comprising a.

In the above manufacturing method, the raw material is Filtering after pretreatment of raw materials selected from petroleum heavy oil, residual oil, naphta cracking botto oil (NCBO), coal tar fraction, or a mixture thereof or to which an oil having a specific carbon number is added. It is a method for producing a raw material for producing isotropic pitch containing.

The raw material may include pyrolized fuel oil (PFO), which is a kind of naphtha cracking process residue. PFO is produced at the bottom of a naphtha cracking center (NCC) and can be used as a raw material of the present invention due to its high degree of aromatization and rich in resin content.

Pyrolysis fuel oil is produced at the bottom of the naphtha cracking process, and is a variety of aromatic hydrocarbons such as benzene, naphthalene, indene and biphenyl as well as saturated compounds. It may include. Specifically, ethylbenzene, 1-ethenyl-3-methyl benzene, indene, 1-ethyl-3-methylbenzene (1-ethyl-3-methyl) benzene),1-methylethylbenzene,2-ethyl-1,3-dimethyl benzene, propylbenzene, 1-methyl-4-( 2-propenyl)-benzene (1-methyl-4-(2-propenyl) benzene), 1,1a,6,6a-tetrahydro-cyclopropaneden (1,1a,6,6a-tetrahydro-cycloprop[ a]indene), 2-ethyl-1H-indene, 1-methyl-1H-indene, 4,7-dimethyl-1H-indene (4 ,7-dimethyl-1H-indene),1-methyl-9H-fluorene,1,7-dimethyl naphthalene, 2-methylindene ), 4,4'-dimethyl biphenyl, naphthalene, 4-methyl-1,1'-biphenyl, anthracene (Anthracene), 2-methylnaphthalene, 1-methylnaphthalene, and the like, and various substituents may further exist.

The raw material may be a raw material containing at least one of petroleum heavy oil, residue oil, naphtha cracking residue and a high boiling fraction, or at least one of petroleum heavy oil, naphtha cracking residue oil, or coal tar oil. The high-boiling fraction refers to a component having a high boiling point and a large number of carbon atoms among components obtained by fractional distillation of crude oil, and may mainly include a light or heavy aromatic naphtha having 5 or more carbon atoms, preferably 7 or more.

The main physical properties of raw materials include the atomic ratio of carbon and hydrogen, degree of aromatization, average molecular weight, and viscosity. Raw materials having a specific range of physical properties are important in the manufacturing method of raw materials for isotropic pitch production.

The atomic ratio (H/C) of the raw material may be 0.90 to 1.10. If the atomic ratio is less than 0.90 or exceeds 1.10, the yield of the raw material for producing isotropic pitch is lowered, and isotropic pitch having an appropriate softening point and average molecular weight may not be produced.

The atomic ratio (H/C) of the raw material may be 0.90 to 1.10. If the atomic ratio is less than 0.90 or exceeds 1.10, the yield of the raw material for producing the isotropic pitch decreases, and the isotropic pitch having an appropriate softening point and viscosity may not be produced.

The weight average molecular weight (Mw) of the raw material may have a distribution of 120 to 260, and preferably may have a distribution of 130 to 240. The proper molecular weight and range of the raw material allows the raw material for isotropic pitch production to be prepared with an appropriate molecular weight and range, and then affects the molecular weight and range of the isotropic pitch, so that the physical properties of the isotropic pitch-based carbon fiber are affected. . Carbon fibers manufactured from low molecular weight raw materials are easily broken, and high molecular weight raw materials affect the length and diameter of carbon fibers, and thus may not be suitable as a raw material for manufacturing high strength and high elastic carbon fibers.

The compounds included in the raw material of the present invention are saturated compounds, compounds containing one aromatic ring, compounds containing two aromatic rings, compounds containing three aromatic rings, four or more, depending on the number of aromatic rings. It may include a compound containing an aromatic ring. In the compound including one or more aromatic rings, the aromatic ring may be a compound including a condensed ring structure as well as a structure in which the aromatic ring is connected by single or multiple bonds, such as biphenyl. Specifically, compounds containing one or more aromatic rings include, but are not limited to, benzene, indenes, naphthalenes, and biphenyls, and compounds containing a wide variety of aromatic rings may exist.

The types of compounds containing aromatic rings in the raw material are very diverse, but among them, there are major compounds whose content needs to be adjusted in the raw material in order to produce an isotropic pitch having desired physical properties and radioactivity.

Among compounds containing one aromatic ring, it is particularly important to control the content of alkenyl benzene and indenes, and among compounds containing two aromatic rings, it is particularly important to control the content of biphenyls and naphthalenes. And, the content of the compound containing three aromatic rings and the compound containing four or more aromatic rings must be adjusted as a whole to prepare the target raw material in the present invention. Further, by using the above raw materials, an isotropic pitch having excellent physical properties and spinnability can be produced, and finally, carbon fibers having high elasticity and high strength properties can be produced. The reason is that in the pitch synthesis step, a mesophase is partially generated in an insoluble solid or synthesized pitch by compounds that do not participate in the reaction or are too reactive. These insoluble solids and mesophase portions become a major factor deteriorating the physical properties and spinnability of the pitch and the mechanical properties of the carbon fiber, so that the isotropic pitch for producing high-strength carbon fibers that is desired in the present invention cannot be obtained.

That is, in order to obtain an isotropic pitch for manufacturing high strength and high elastic carbon fibers, it is necessary to use a raw material having very limited conditions and a raw material prepared from a manufacturing method using the same.

The content of compounds contained in the raw material and their ratio are as follows .

First, in terms of the content of the compound contained in the raw material, the compound containing one aromatic ring is preferably 30.0 to 60.0% by weight based on the total amount of the raw material. Among them, indenes may be partially converted to naphthalenes during the pretreatment process, but since they are materials with strong reactivity, the physical properties and radioactivity of the isotropic pitch prepared from the raw material according to the present invention may adversely affect the properties, so the content needs to be adjusted. The content of indenes is 25.0 to 70.0% by weight, preferably 30.0 to 65.0% by weight, based on the total amount of the compound containing one aromatic ring, and 5.0% to 50.0% by weight, preferably 10.0 to 40.0, based on the total amount of the raw material. It is weight percent. In addition, alkenyl benzenes, which are olefins, also have very strong reactivity similar to indenes, but are mostly volatilized during the pretreatment process, so their content is not greatly limited, and preferably 3.0% by weight or less.

The compound containing two aromatic rings is 30.0% by weight or more, preferably 35.0 to 65.0% by weight, based on the total amount of the raw material. Among them, the content of naphthalenes should be 30.0% by weight or more, preferably 35.0% by weight or more, and 10.0% by weight or more, preferably 10.0 to 45.0% by weight, based on the total amount of the compound containing two aromatic rings. After that, it is possible to produce a raw material for producing isotropic pitch containing sufficient naphthalenes. Since biphenyls do not contribute significantly to the polymerization reaction, it is preferable that their content is small, but 15.0% by weight or less, preferably 10.0% by weight or less, and 10.0% by weight or less of the total amount of raw materials. , Preferably 5.0% by weight or less, more preferably a very small amount or not so that it cannot be measured.

Compounds containing three aromatic rings and compounds containing four or more aromatic rings do not participate in the polymerization reaction or condensed aromatics having an excessively large number of rings under the influence of olefins such as alkenyl benzene and leadene compounds such as indene. Cyclic compounds can be formed. That is, if the content of a compound containing three aromatic rings and a compound containing four or more aromatic rings is large, raw materials suitable for producing isotropic pitch having excellent physical properties and radioactivity may not be prepared. The compound containing three aromatic rings is preferably 8.0% or less, preferably 5.0% by weight or less, and more preferably in a very small amount so as not to be measurable, relative to the total amount of the raw material. It is preferable that the compound containing four or more aromatic rings is 3.0% by weight or less, or preferably contains or does not contain a very small amount to the extent that it cannot be measured.

Next, the content ratio of the compound contained in the raw material is as follows.

Each of the content ratio (by weight) of a compound containing an aromatic ring is in the _{Ar 1 / Ar 2 0.50 <Ar} 1 / Ar 2 <2.00, preferably _{0.55 <Ar 1 / Ar 2 <} 1.75. Next, in Ar ₁ /Ar ₃ , 5.00 <Ar ₁ /Ar ₃ <30.00, preferably 8.00 <Ar ₁ /Ar ₃ <25.00. And in Ar ₂ /Ar ₃ , 5.00<Ar ₂ /Ar ₃ <20.00, preferably 10.00<Ar ₂ /Ar ₃ <15.00 to be. In the above content ratio, Ar ₁ is the content of the compound containing one aromatic ring relative to the total amount of the raw material, Ar ₂ is the content of the compound containing two aromatic rings relative to the total amount of the raw material, and Ar ₃ is the content of the compound containing two aromatic rings relative to the total amount of the raw material. It indicates the content of the compound containing two aromatic rings. In addition, the content of the compound containing four or more aromatic rings relative to the total amount of the raw material can be expressed as _{Ar 4.}

The content ratio (weight ratio) of indenes and naphthalenes to the total amount of raw materials is 0.20<indenes weight/naphthalenes weight <4.00, preferably 0.25<indenes weight/naphthalenes weight<3.50.

The content ratio (weight ratio) of biphenyls and naphthalenes to the total amount of the compound containing two aromatic rings is biphenyls weight/naphthalenes weight <0.15, preferably biphenyls weight/naphthalenes weight <0.10.

In the production method of the present invention, it is most preferable to use a raw material that satisfies the compound contained in the raw material and the content ratio thereof. According to an embodiment of the present invention Ar ₁ , When the content of _{Ar 2 and Ar 1} /Ar ₂ are satisfied, raw materials for isotropic pitch can be prepared. Further, more specifically, the content and ratio of specific compounds such as indenes, naphthalenes, and biphenyls may be further adjusted to prepare a raw material for isotropic pitch production.

On the other hand, according to an embodiment of the present invention, when a raw material that partially satisfies the content and ratio of the compounds described above is used, the content and ratio of the raw material may not be appropriate. For example, indenes/naphthalenes are important in the content ratio (weight ratio), but if it is outside the above preferred range, the content and ratio of raw materials for isotropic pitch production may not be appropriate even if other conditions are satisfied.

The manufacturing method that satisfies the conditions of the raw material described above,

(a) pretreatment by heat treatment and fractionation of raw materials satisfying the following formulas (1) to (4) as petroleum-based heavys, naphtha decomposition residue oil, coal tar, or a mixture thereof; And

30.0 ≤ Ar ₁ ≤ 60.0% by weight --- (1)

35.0 ≤ Ar ₂ ≤ 65.0% by weight --- (2)

0.0 ≤ Ar ₃ ≤ 5.0% by weight --- (3)

0.55 <Ar ₁ /Ar ₂ <1.75 --- (4)

(b) filtering the raw material pretreated in (a);

It can be represented by a method of manufacturing a raw material for isotropic pitch production comprising a.

According to an embodiment of the present invention, a raw material capable of producing an isotropic pitch having a high carbonization yield while not causing single yarn during spinning or having an extremely low single yarn frequency when spinning must be satisfied with all of the above conditions is prepared, and further prepared from the isotropic pitch. The carbon fiber to be used may have a remarkably high strength of at least 1.5 GPa, and the elongation may be 2% or more.

In the raw material satisfying (1) to (4) of the above preparation method, the content of indenes relative to the total amount is 10.0 to 40.0% by weight, and the content of naphthalenes is preferably 10.0 to 45.0% by weight. According to an embodiment of the present invention, when any one or more of indenes or naphthalenes does not satisfy the above range, single yarn occurs during spinning or isotropic pitch having a low carbonization yield is produced, and further, carbon fibers produced from the isotropic pitch The strength of the material is rapidly decreased or the elongation rate is also decreased.

In the manufacturing method of the present invention, the pretreatment step may include heat treatment and fractionation, and in the pitch synthesis step, a low molecular weight substance that is unlikely to be polymerized by a polymerization reaction is removed. The contained compound is removed. The pretreatment step may be performed at normal pressure at a temperature of 150 to 250°C, preferably 190 to 220°C until no volatile matter is generated, or may be performed under pressure or reduced pressure. At this time, the pretreatment process can be performed at a lower temperature through reduced pressure, and when pressurized, the pretreatment process is performed at a higher temperature, but there is an advantage of being able to fractionate more precisely by supplementing the design of the device. The pretreatment process can freely control the pressure and temperature within a range that can obtain the same effect as normal pressure.

In the pretreatment step, some of the components constituting the raw material are chemically converted to become positive or negative components for the pitch synthesis reaction, and depending on conditions, some of the components acting as important reactants in the pitch synthesis step may be volatilized. Accordingly, the heating temperature in the pretreatment step may affect the composition ratio of the components included in the raw material for producing the isotropic pitch and the mechanical properties of the isotropic pitch and carbon fibers that can be produced therefrom.

The filtration process is a process of removing solid substances, and these solid substances are solid residues containing impurities such as metals, sulfur, and nitrogen, and may cause defects or cracks in the manufacture of carbon fibers, thereby reducing strength deterioration.

The filtration step may be performed in a manner commonly performed in the art, for example, filtration, centrifugation, sedimentation, adsorption, extraction, and the like.

The physical properties and the composition of the compound of the raw material for producing the isotropic pitch prepared according to the production method of the present invention can be used in the production of the isotropic pitch having excellent physical properties and spinnability.

The degree of aromatization of the prepared raw materials is 0.75 to 0.95, preferably 0.80 to 0.90, and the average molecular weight is 100 to 300, preferably 150 to 250. And, Ar' ₁ of the raw material is 20.0 to 40.0% by weight, Ar' ₂ is 55.0 to 70.0% by weight, their content ratio (weight ratio) is 0.30 <Ar' ₁ / Ar' ₂ <0.70, Ar' ₃ is 10.0% by weight or less, preferably 8.0% by weight or less, and more preferably, it is preferable that a very small amount is included or not so that it cannot be measured. In addition, _{it is preferable that Ar' 4} is 5.0% by weight or less, and preferably contains or does not contain a very small amount so that it cannot be measured.

More specifically, relative to the total amount of raw materials, indenes are 8.0 to 27.5% by weight, naphthalenes are 15.0 to 60.0% by weight, and their content ratio (weight ratio) is 0.15<indenes weight/naphthalenes weight <1.50, and the total amount of raw materials In contrast, biphenyls are preferably less than 8.0% by weight, and the content ratio (weight ratio) of biphenyls and naphthalenes is preferably less than 0.15.

Ar' ₁ is the content of a compound containing one aromatic ring relative to the total amount of the raw material, Ar' ₂ is the content of a compound containing two aromatic rings relative to _{the total amount of the raw material, Ar' 3} is three aromatics relative to the total amount of the raw material. The content of the compound containing a ring, Ar' ₄ is the content of the compound containing four or more aromatic rings relative to the total amount of the raw material.

The physical properties of the raw material and the composition of the compound satisfy very restrictive conditions for producing an isotropic pitch having excellent physical properties and spinnability.

The isotropic pitch may be prepared from the raw material for producing the isotropic pitch according to the present invention by a thermal polymerization method or a halogenation method, but is not limited thereto. According to an embodiment of the present invention, the isotropic pitch is manufactured by the thermal polymerization method, but the isotropic pitch manufactured by the halogenation method may have improved physical properties than the isotropic pitch manufactured by the thermal polymerization method.

The raw material for producing an isotropic pitch according to the present invention is suitable for producing an isotropic pitch having very good spinning properties. The isotropic pitch is capable of melt spinning and has excellent spinnability to the extent that long carbon fibers can be produced through it, and has excellent carbonization yield. It is possible to manufacture isotropic pitch-based carbon fibers having high strength and high elasticity. Specifically, the raw material for isotropic pitch according to the manufacturing method of the present invention is an isotropic pitch structure in which a continuous polymer structure in which condensation polymerization aromatic molecules are connected by an aliphatic chain is stacked, and the aliphatic chain is too short or the aliphatic side chain is minimized. The carbonization yield and the strength of the carbon fiber can be remarkably increased.

In addition, the generation of extremely fine insoluble solids, which are difficult to measure with the current analysis technology, or structures in which relatively short molecular chains are thickly stacked in the isotropic pitch structure are not removed in the filtration step, causing the problem of increasing the single yarn frequency during melt spinning. However, the raw material of the isotropic pitch prepared according to the present invention solves the above problem and is suitable for producing an isotropic pitch in which single yarns are extremely rare or do not occur during melt spinning.

The carbon fiber may be manufactured through a stabilization step and a carbonization step after melt spinning of an isotropic pitch, but is not limited thereto. In the carbon fiber manufacturing step, a binding agent for preventing adhesion between fibers may be used, and surface treatment and sizing steps may be added after the carbonization step to improve adhesion to the matrix resin when manufacturing the composite material. In addition, the spinning conditions can be freely changed depending on the number of holes in the spinning machine or the capacity of the manufacturing facility.

Hereinafter, the method for manufacturing an isotropic pitch according to the present invention will be described in more detail through examples. In the following examples, each of the examples and comparative examples corresponds to an example for preferably carrying out the present invention, and the present invention is not limited thereto.

How to measure physical properties

1. Carbon and hydrogen atomic ratio (H/C)

It was measured with a CHNS elemental analyzer.

2. Aromatization degree (fa)

^{Measured by 13} C NMR (ASTM D5292).

3. Average molecular weight (Mw)

Measured by TOF-MS.

4. Composition analysis

A liquid sample was collected, diluted with an appropriate amount of DCM (Dimethylchloride), and analyzed with 2D-GC.

5. Softening point (℃)

The softening point was measured by TMA (Thermo Mechanical Analyzer).

6. Yield

The yield was calculated by the weight of the final pitch obtained relative to the weight of the raw material input.

7. Carbonization yield

The carbonization yield was calculated by the weight of the finally obtained carbon fiber relative to the weight of the melt-spun isotropic pitch fiber.

8. Mechanical properties

In order to calculate the tensile strength (GPa) and elongation (%), the stress-strain curve was measured with a UTM (Universal Test Machine) equipped with a 2N load cell for a sample of carbon fiber, and the tensile strength was determined by the above measurement result and an electron microscope. It was calculated from the diameter of the fiber analyzed by.

<Examples and Comparative Examples>

Isotropic pitch Preparation of raw materials for manufacturing

Naphtha Cracker Bottom Oil (NCBO) was prepared as a raw material. The physical properties of NCBO and the composition of the compound used in Examples 1 to 3 and Comparative Examples 1 to 2 are shown in Tables 1 to 5.

Atomic ratio (H/C) Aromatization degree (fa) Average molecular weight (Mw) Comparative Example 1 1.12 0.60 120 Example 1 0.96 0.74 170 Example 2 1.10 0.65 140 Example 3 0.93 0.80 220 Comparative Example 2 0.92 0.85 260

Saturated carbide (% by weight) Aromatic ring
1 included
(Ar ₁ ) (% by weight) Includes 2 aromatic rings
(Ar ₂ ) (% by weight) Contains 3 aromatic rings
(Ar ₃ ) (% by weight) Aromatic ring
4 or more included
(Ar ₄ ) (% by weight) Total amount
(%) Comparative Example 1 2.3 62.4 33.2 2.1 0 100 Example 1 1.8 51.8 43.1 3.4 0 Example 2 1.7 59.8 35.7 2.8 0 Example 3 1.4 34.2 59.8 4.1 0.5 Comparative Example 2 1.5 29.6 56.3 8.4 4.2

Referring to Table 2, Ar ₁ in the example was 34.2 to 51.8 wt%, Ar ₂ was 35.7 to 59.8 wt%, Ar ₃ was 4.1 wt% or less, and Ar ₄ was 0.5 wt% or less. Among these content ratios, Ar ₁ /Ar ₂ belonged to 0.570 to 1.670, Ar ₃ /Ar ₂ to 0.068 to 0.078, and Ar ₁ /Ar ₃ to 8.340 to 21.350.

Compound containing one aromatic ring (% by weight) Total amount
(%) Alkyl benzene Alkenyl benzene Indan derivatives Indens Etc Comparative Example 1 6.1 4.6 3.4 66.0 19.9 100 Example 1 6.9 5.4 3.3 52.7 31.7 Example 2 5.2 4.0 3.2 65.0 22.7 Example 3 8.5 6.7 6.1 31.0 47.7 Comparative Example 2 10.8 8.4 8.1 29.0 43.6

Compound containing two aromatic rings (% by weight) Total amount (%) Biphenyls Naphthalene Etc Comparative Example 1 1.2 34.0 64.8 100 Example 1 0.5 62.1 37.4 Example 2 0.3 35.0 64.7 Example 3 6.5 68.9 24.6 Comparative Example 2 11.5 73.7 14.7

If the results from Table 2 to Table 4 are summarized and summarized, it can be expressed in the composition shown in Table 5.

Saturated carbide (% by weight) Aromatic ring
Includes 1 (% by weight) Aromatic ring
Includes 2 (% by weight) Aromatic ring
Three
Included (% by weight) Aromatic ring
4
Contains more than (% by weight) Total amount
(%) Alkylbenzene Alkenylbenzene Indanyu Indens Etc Biphenyls Naphthalene Etc Comparative Example 1 2.3 3.8 2.9 2.1 41.2 12.4 0.4 11.3 21.5 2.1 0 100 Example 1 1.8 3.6 2.8 1.7 27.3 16.4 0.2 26.7 16.1 3.4 0 100 Example 2 1.7 3.1 2.4 1.9 38.9 13.5 0.1 12.5 23.1 2.8 0 100 Example 3 1.4 2.9 2.3 2.1 10.6 16.3 3.9 40.2 15.7 4.1 0.5 100 Comparative Example 2 1.5 3.2 2.5 2.4 8.6 12.9 6.5 41.5 8.3 8.4 4.2 100

Referring to Table 5, in the examples, the content of indenes was 10.6 to 38.9% by weight, the content of naphthalenes was 12.5 to 40.2% by weight, and the content of biphenyls was 0.1 to 3.9% by weight. Among these content ratios, the weight of indenes/naphthalenes was 0.26 to 3.11, and the weight of biphenyls/naphthalenes was 0.007 to 0.094.

NCBO having the physical properties and compound composition as shown in Tables 1 to 5 were distilled under atmospheric pressure at a pretreatment temperature of 200° C. until no volatile matter was generated and filtered to prepare a raw material for isotropic pitch production. The physical properties of the raw materials for preparing the prepared isotropic pitch and the composition of the compound are shown in Tables 6 to 10.

Atomic ratio (H/C) Degree of aromatization
(fa) Average molecular weight
(Mw) Comparative Example 1 1.11 0.65 150 Example 1 0.94 0.84 220 Example 2 1.05 0.82 170 Example 3 0.93 0.86 250 Comparative Example 2 0.92 0.89 270

Saturated carbide (% by weight) Aromatic ring
1 included
(Ar' ₁ ) (% by weight) Aromatic ring
Includes 2
(Ar' ₂ ) (% by weight) Aromatic ring
Includes 3
(Ar' ₃ ) (% by weight) Aromatic ring
4 or more included
(Ar' ₄ ) (% by weight) Total amount
(%) Comparative Example 1 0.9 41.2 52.3 5.6 0 100 Example 1 1.3 30.0 61.4 7.3 0 Example 2 1.5 36.2 55.5 6.8 0 Example 3 1.2 22.5 66.6 7.4 2.3 Comparative Example 2 1.3 19.8 61.9 10.5 6.5

Referring to Table 7, Ar' ₁ of the example was 22.5 to 36.2 wt%, Ar' ₂ 55.5 to 66.6 wt%, Ar' ₃ 6.8 to 7.4 wt%, and Ar' ₄ belonged to 2.3 wt% or less. Among these content ratios (weight ratio), Ar' ₁ /Ar' ₂ was 0.33 to 0.65, Ar' ₃ /Ar' ₂ was 0.11 to 0.12, and Ar' ₁ /Ar' ₃ was 3.04 to 5.32.

Compound containing one aromatic ring (% by weight) Total amount
(%) Alkyl benzene Alkenyl benzene Indan derivatives Indens Etc Comparative Example 1 7.3 0 8.3 71.6 12.9 100 Example 1 8.3 0 13.3 56.7 21.6 Example 2 7.7 0 10.5 70.2 11.6 Example 3 13.8 0 20.9 40.4 24.9 Comparative Example 2 19.2 0 24.7 34.3 21.7

Compound containing two aromatic rings (% by weight) Total amount (%) Biphenyls Naphthalene Etc Comparative Example 1 8.0 27.3 64.6 100 Example 1 7.7 52.0 40.4 Example 2 6.8 39.1 54.1 Example 3 7.4 73.9 18.8 Comparative Example 2 12.6 76.0 11.4

Saturated carbide (% by weight) Aromatic ring
Includes 1 (% by weight) Aromatic ring
Includes 2 (% by weight) Aromatic ring
Three
Included (% by weight) Aromatic ring
4
More than
Included (% by weight) Total amount
(%) Alkylbenzene Alkenylbenzene Indanyu Indens Etc Biphenyls Naphthalene Etc Comparative Example 1 0.9 3.0 0.0 3.4 29.5 5.3 4.2 14.3 33.8 5.6 0.0 100 Example 1 1.3 2.5 0.0 4.0 17.0 6.5 4.7 31.9 24.8 7.3 0.0 100 Example 2 1.5 2.8 0.0 3.8 25.4 4.2 3.8 21.7 30.0 6.8 0.0 100 Example 3 1.2 3.1 0.0 4.7 9.1 5.6 4.9 49.2 12.5 7.4 2.3 100 Comparative Example 2 1.3 3.8 0.0 4.9 6.8 4.3 7.8 47.0 7.1 10.5 6.5 100

Table 10 shows that most of the alkenylbenzene was volatilized from the raw material through the pretreatment process of the naphtha decomposition residue, and the contents of alkylbenzene and phosphorus were reduced as a whole. On the other hand, compounds containing indans, biphenyls, and three or more aromatic rings increased slightly overall, and the content of naphthalenes increased significantly. In Examples, the content of indenes among the main compounds was 9.1 to 25.4% by weight, the content of naphthalenes was 21.7 to 49.2% by weight, and the content of biphenyls was 3.8 to 4.9% by weight. Among these content ratios (weight ratio), the weight of indenes/naphthalenes was 0.18 to 1.17, and the weight of biphenyls/naphthalenes was 0.11 to 0.12.

Isotropic Manufacture of pitch

100 parts by weight of a raw material for producing isotropic pitch was put into a metal container and heated at 370° C. for 0.5 hours. After the process was completed, an isotropic pitch was prepared by heating at 340° C. for 10 minutes in a vacuum atmosphere in a thin film evaporator.

The isotropic pitches prepared according to Examples 1,2 and 3 were melt spinning, and no single yarns occurred when spinning at 700 rpm for 20 minutes, and Comparative Examples 1 and 2 had 7 and 5 single yarns, respectively. The single yarn frequency is shown in Table 11.

Carbon fiber Produce

Carbon fibers were prepared with the prepared isotropic pitch. In the melt spinning, the isotropic precursor pitch was injected into a cylindrical container, and then spun by applying a pressure of ^{0.8 kgf/cm 2 in a nitrogen atmosphere.} At this time, the diameter of the take-up machine was 150 mm, and the take-up speed was 700 rpm. After melt-spinning, the pitch fibers after spinning were each charged into a tubular electric furnace, and air was supplied at a flow rate of 150 ml/min. In addition, the temperature was raised at a rate of 1°C/min, and after reaching 290°C, it was maintained for 1 hour to stabilize. In the carbonization step after the stabilization process, the pitch fiber was injected at a rate of 150 ml/min of nitrogen and heated at a rate of 5° C./min to reach 800° C. and maintained for 0.5 hours to prepare a carbon filament. The mechanical properties of the prepared carbon filaments were measured and described in Table 11.

Single yarn frequency Diameter(㎛) Tensile strength (Gpa) Elongation (%) Carbonization yield (%) Comparative Example 1 7 6.89 0.8 2.8 52 Example 1 0 7.34 1.7 2.3 72 Example 2 0 7.02 1.5 2.1 65 Example 3 0 8.21 1.6 2.2 79 Comparative Example 2 5 8.32 1.1 1.9 68 Single yarn frequency is measured as the frequency of interruption during continuous spinning for 20 minutes

Referring to Table 11, in Examples 1, 2, and 3, single yarns did not occur during continuous spinning for 20 minutes, but in Comparative Example 1, 7 times, and in Comparative Example 2, 5 single yarns occurred. In addition, Examples 1, 2 and 3 were able to prepare isotropic carbon fibers having an elongation of 2% or more while having an isotropic pitch having an appropriate softening point and a tensile strength of at least 1.5 GPa, and 65%, 72% and 79%, respectively, from raw materials. Carbon fibers having a high carbonization yield could be produced. On the other hand, in Comparative Examples 1 and 2, an isotropic pitch having a softening point and viscosity of too high or low was prepared, so that the physical properties of the carbon fiber according to the diameter were deteriorated, and the tensile strength of the carbon fiber was also 0.8 GPa and 1.1 GPa, which was significantly inferior to that of the Example.

Through this, raw materials satisfying very restrictive conditions as in Examples 1, 2, and 3 are used to produce isotropic pitch raw materials having excellent spinnability and physical properties, and isotropic pitch prepared using these raw materials has excellent physical properties and spinnability. Furthermore, it can be seen that high-strength and high-elasticity carbon fibers can be manufactured.

Claims (11)

(a) pretreatment by heat treatment and fractionation of raw materials satisfying the following formulas (1) to (4) as petroleum-based heavys, naphtha decomposition residue oil, coal tar, or a mixture thereof; And
30.0 ≤ Ar ₁ ≤ 60.0% by weight --- (1)
35.0 ≤ Ar ₂ ≤ 65.0% by weight --- (2)
0.0 ≤ Ar ₃ ≤ 5.0% by weight --- (3)
0.55 <Ar ₁ /Ar ₂ <1.75 --- (4)
(b) filtering the raw material pretreated in (a);
Method for producing a raw material for isotropic pitch production comprising a.
(The Ar ₁ is the content of the compound containing one aromatic ring relative to the total amount of the raw material, the Ar ₂ is the content of the compound containing two aromatic rings relative to the total amount of the raw material, and Ar ₃ is three aromatics relative to the total amount of the raw material. It is the content of the compound containing the ring.) The method of claim 1,
The raw material is a raw material that satisfies the total amount of 10.0% by weight ≤ indenes ≤ 40.0% by weight and 10.0% by weight ≤ naphthalene ≤ 45.0% by weight. The method of claim 2,
The raw material is a method of producing a raw material for isotropic pitch that satisfies 0.25 <weight of indenes / weight of naphthalenes <3.50. The method of claim 3, wherein the raw material is a raw material that satisfies biphenyls ≤ 5.0% by weight relative to the total amount. The method of claim 1,
The raw material is a method for producing a raw material for isotropic pitch production satisfying _{Ar 4 ≤3.0% by weight.}
(The Ar ₄ is the content of a compound containing four or more aromatic rings relative to the total amount of the raw material.) The method according to any one of claims 1 to 5,
The heat treatment is a method for producing a raw material for isotropic pitch production proceeds until no volatile matter is generated at 190 to 220°C. The method of claim 6,
The raw material is a method for producing a raw material for isotropic pitch production satisfying the following (1) to (4).
20.0 ≤ Ar' ₁ ≤ 40.0% by weight --- (1)
55.0 ≤ Ar' ₂ ≤ 70.0% by weight --- (2)
0.0 ≤ Ar' ₃ ≤ 8.0% by weight --- (3)
0.30 <Ar' ₁ /Ar' ₂ <0.70 --- (4)
(The Ar' ₁ is the content of a compound containing one aromatic ring relative to the total amount of raw materials, Ar' ₂ is the content of a compound containing two aromatic rings relative to the total amount of raw materials, and Ar' ₃ is three aromatics relative to the total amount of raw materials. It is the content of the compound containing the ring.) The method of claim 7,
The raw material is a method of producing a raw material for isotropic pitch that satisfies 8.0≤indenes≤27.5% by weight and 15.0≤naphthalenes≤60.0% by weight relative to the total amount. The method of claim 8,
The raw material is a method of manufacturing a raw material for isotropic pitch that satisfies 0.15 <weight of indenes/weight of naphthalenes <1.50. The method of claim 9,
The raw material is a method for producing a raw material for isotropic pitch that satisfies the total amount of biphenyls ≤ 6.0% by weight and the weight of biphenyls / weight of naphthalenes <0.15. The method of claim 6,
The raw material is Ar' _{4 A} method of producing a raw material for producing an isotropic pitch satisfying ≤5.0% by weight.
(The Ar' ₄ is the content of a compound containing four or more aromatic rings relative to the total amount of raw materials.)

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