JPH09263769A - Binder pitch for carbon material and method for assessing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a binder pitch which gives a carbon material having high mechanical strengths in a high carbonization yield and to provide a method for simply, conveniently, quickly, and accurately assessing the same. SOLUTION: The quinoline-sols. of this pitch has such a mol.wt.% (Mw) distribution by gel permeation chromatography that in the distribution fractions with an Mw of 150 or lower are not substantially existent; the amt. of fractions with an Mw of 2,000-4.000 is 5-10%; the rest is fractions with an Mw higher than 150 but lower than 2,000; and pref. there are only two peaks, one at an Mw of 230 and the other at an Mw of 8,000. The pitch is assessed by using the amt. of the fractions with an Mw of 150 or lower and the amt. of the fractions with an Mw of 2,000-4,000.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a graphite electrode for steelmaking,
Aluminum smelting electrode, graphite anode for electrolytic soda production,
The present invention relates to a binder pitch for carbon materials, which is a raw material for carbon products such as carbon for machines and chemical devices and carbon refractories (hereinafter referred to as carbon materials), and an evaluation method thereof.

[0002]

2. Description of the Related Art At present, carbon materials such as graphite electrodes for steelmaking and electrodes for smelting aluminum are generally manufactured by solidifying aggregate coke such as petroleum coke and pitch coke with a binder such as binder pitch and firing and graphitizing. Has been done.
Binder pitch, which is one of the raw materials of this carbon material, is produced from coal-based and petroleum-based raw material tar, and the residue obtained by distilling this raw material tar and distilling off low boiling point oil becomes binder pitch, which is currently used. Most of the binder pitches used are coal tar pitches.

The most preferred binder pitch is a coal tar pitch obtained by distilling high temperature dry-distilled coal tar. Although the pitch having the required properties as a binder pitch can be obtained, the quality is still unsatisfactory. It was enough and there was room for improvement. The binder pitch is required to have a low viscosity and a large fixed carbon content.

In the production of carbonaceous material, this is generally because after kneading aggregate coke and binder pitch and molding,
Further, it is calcined and graphitized to obtain a carbon material, but the lower the binder pitch viscosity, the easier the handling when kneading the aggregate coke and the binder pitch, and the more uniform the mixing state with the aggregate coke. Is. Further, the larger the fixed carbon content of the binder pitch, the larger the carbonization yield during firing, and as a result, the bulk specific gravity of the carbon material increases and the mechanical strength increases.

As a method of evaluating the binder pitch, it is general to measure the softening point and the amount of solvent insolubles such as the amount of toluene insolubles and the amount of quinoline insolubles in the pitch.
That is, for example, in JP-A-2-169692,
There is disclosed a method for forming a binder pitch by limiting the softening point, the amount of acetone-soluble matter, and the amount of quinoline-insoluble matter and preparing a pitch having a high softening point.

The most important required properties of the binder pitch are, as described above, a low viscosity and a large fixed carbon content. There is a softening point as an index showing the viscosity characteristics of the binder pitch, and further, there is a method of measuring the fixed carbon amount, but since the pitch is a mixture of extremely many kinds of polycyclic aromatic hydrocarbons, its It is difficult to accurately evaluate the properties and composition.

In addition to the measurement of the softening point and the fixed carbon content, conventional methods for evaluating the binder pitch include elemental analysis and solvent division using various organic solvents. Pretreatment such as adjustment of the particle size of the test sample is required, which requires a lot of time.

[0008]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and when used as a raw material for producing a carbon material, the obtained carbon material has a large mechanical strength and a large carbonization yield. It is an object of the present invention to provide a binder pitch for raw materials and a method capable of evaluating the performance as a binder pitch for carbon materials quickly and accurately by a simpler method.

[0009]

[Means for Solving the Problems] The first invention is the molecular weight of the quinoline-soluble component of the binder pitch for carbon material by gel permeation chromatography (hereinafter also referred to as GPC) using quinoline as a solvent. (M _W) and measuring the distribution, M _W is substantially free of 150 following ingredients, and M _W is 2000 or higher, 40,000 following ingredients containing 5-10%, balance M _W 150 exceeds, 2000
It is a binder pitch for carbon materials, which is characterized by containing less than the following components.

In the first aspect of the invention, in the measurement of the molecular weight (M _W ) distribution, the peak of the molecular weight distribution is
It is preferably composed of only two peaks of M _W = 230 and M _W = 8000, and further, it is preferable that the quinoline insoluble content of the binder pitch for carbon material is 5 to 15 wt%. In addition, M _W in the first invention is
The content of the component of 2000 or more and 40,000 or less indicates the area% in the peak area on the GPC chart (hereinafter referred to as area%).

A second aspect of the present invention, by gel permeation chromatography using quinoline as a solvent, the molecular weight of quinoline soluble matter of binder pitch for carbon materials (M _W) distribution was measured, M _W 150 following components Quantity and M _W is 2000
A method for evaluating a binder pitch for a carbon material, characterized in that the moldability when the pitch is used and the mechanical strength of the obtained carbon material are evaluated based on the component amounts of up to 40,000.

In the second invention, the amount of quinoline insoluble matter is 5
It is preferably applied as a method for evaluating the binder pitch for carbon material, which is ˜15 wt%.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The manufacturing process of a carbon material such as an artificial graphite electrode for steelmaking is roughly divided into the following three processes. (1): A step of kneading aggregate coke and binder pitch.

(2): A step of molding the kneaded product obtained in (1). (3): A step of firing and graphitizing (2000 ° C or higher) the molded product obtained in (2) at a temperature of 800 ° C or higher to obtain a baked product and a graphitized product. In the step (3), the binder pitch is carbonized and the particles of the aggregate coke are bonded to each other to form a tissue skeleton of the carbon material.

As a result of investigating the relationship between the characteristics of the binder pitch and the production process of the carbon material, the inventors of the present invention have found that the quinoline content in the binder pitch is in the molecular weight distribution of the binder pitch measured by GPC using quinoline as a solvent. Amount of component of molecular weight M _W of 150 or less and M _W of 2
It has been found that there is a close relationship between the amounts of components of 000 to 40,000 and the kneadability, moldability, carbonization and graphitization characteristics during the production of carbon materials.

In the above molecular weight distribution, M _W is 15
0 substantially free of the following ingredients, and M _W is 2000 to 4000
It has been found that a pitch containing 5 to 10 area% of a component of 0 is an excellent binder pitch for a carbon material which has a large mechanical strength and a large carbonization yield. The characteristics that the binder pitch must have are as follows for each step of the carbon material manufacturing process: (1) kneading, (2) molding, (3) firing, and graphitization.

(1): In order to have a softening point at which the coke with the mating aggregate coke is sufficiently mixed and to improve the wettability between the binder pitch and the aggregate coke, the binder pitch is appropriately selected. Contain a quantity and quality of oil and low molecular weight components. (2): The kneaded product that is kneaded into a paste has good moldability at the time of molding, has low fluidity in order to obtain a good molded product, and prevents deterioration of pitch due to heating during molding. In order to reduce its temperature sensitivity and to be thermally stable, the binder pitch contains an appropriate amount and quality of the polymeric component.

(3): In order to form a binder coke having good crystallinity and further to increase the carbonization yield, the polymer component is contained in an appropriate amount and quality. The present inventors have found an effective quality evaluation method for the properties of the binder pitch required in the above (1) to (3), particularly the composition of the low molecular component and the high molecular component, which are important properties.

Since the pitches are aggregates composed of an extremely large variety of polycyclic aromatic hydrocarbons as described above, the conventional methods for evaluating the pitches are analysis of softening point, solvent splitting, fixed carbon and the like. , Measurement is not enough. For this reason,
Instead of these characteristic values, a method capable of accurately and quickly evaluating the characteristics of the binder pitch is required.

In the kneading step of the carbon material manufacturing step, in order for the binder pitch and the aggregate coke to be sufficiently mixed, it is necessary that the pitch contains an appropriate amount and quality of a low molecular weight component. However, if the low-molecular weight component is excessively contained, a paste-like kneaded product having a uniform composition does not form, and there arises a problem that molding cannot be performed in the subsequent molding process.

Further, if the low-molecular component is excessively contained, these components become volatile components in the main kneading step, which is not preferable from the viewpoint of environment and workability. Further, also in the carbonization and graphitization steps, the low-molecular component is volatilized, causing defects such as pores in the carbon material, which is not preferable. That is, the presence of an excessively low molecular weight component adversely affects the kneading, molding, carbonization, and graphitization steps, so that the amount and quality of the low molecular weight component must be specified.

Further, as other required characteristics of the binder pitch, from the viewpoint of thermal stability in the molding, carbonization and graphitization steps and the carbonization yield defined by the fixed carbon content, the polymer component is contained in the binder pitch. Is preferably included. As mentioned above, the most preferred binder pitch is coal tar pitch obtained by distilling high temperature carbonized coal tar.

In the coal tar pitch, usually, solid particles called carbon containing carbon as a main component are present, and they are insoluble in any solvent. Quinoline is known as a solvent that has a strong dissolving power for tar and pitch, which are composed of an extremely large number of polycyclic aromatic hydrocarbons, and the components of coal tar pitch are roughly classified into those soluble in quinoline. It is divided into a component (hereinafter referred to as a quinoline-soluble component) and a component insoluble in quinoline (hereinafter referred to as a quinoline-insoluble component), and the above-mentioned free carbon is a quinoline-insoluble component.

The binder pitch usually contains 5 to 15 wt% of the quinoline insoluble matter. This quinoline insoluble matter is contained in the free carbon originally contained in the coal tar and in the production of the binder pitch. It is formed from both of the quinoline insoluble matter generated by heat treatment. This quinoline-insoluble matter has no caking property by itself,
It is a component necessary for increasing the bulk specific gravity of the carbon material and improving the mechanical strength.

The coal tar pitch is composed of about 5 to 15 wt% of the quinoline-insoluble matter and about 85 to 95 wt% of the quinoline-soluble matter. The molecular weight distribution of the constituents of this quinoline-soluble component is important. The present inventors have found a binder pitch having excellent properties, and measured the molecular weight distribution of the quinoline-soluble component of the pitch by the following method.

-Analytical method: GPC (gel permeation chromatography) -Measuring device: Waters (USA) pump: 6000A type detector: RI 401-Column: Shodex (Showa Denko KK) GPC AQ-803S × 2 (: column connected to two series) column temperature: 80 ° C., the solvent; quinoline Flow rate; 1 ml / min · normal sample; polyethylene glycol weight average molecular weight ^{_{(M W) = 10 5,}} 2 × 10 4, 7500, 3000, 1000, 300 As a result of measuring the molecular weight distribution of the quinoline-soluble component of the binder pitch having excellent properties using the above method, it was found that the binder pitch is a component having a molecular weight M _W of 150 or less for low molecular weight components. It was revealed that a pitch containing 5 to 10% by area of a component having a M _W of 2000 to 40,000 is preferable as a high molecular weight component.

Furthermore, the peak of the molecular weight distribution of this binder pitch is composed of two peaks of M _W = 230 and M _W = 8000, and the molecular weight distribution having a peak at M _W = 8000 is M _W = 2000-40000. Equivalent to. Among the binder pitches for carbon materials, pitches containing components with M _W of 150 or less are
This component becomes a volatile component during kneading, which poses a problem in terms of environment and workability, and further has an adverse effect on the fluidity of the paste in the molding process, and also tends to cause defects such as pores in the carbon material during firing. Therefore, it is not preferable.

When the content of the component within the range of M _W = 2000 to 40,000 is less than 5% by area, the fixed carbon amount necessary for the pitch is reduced, the carbonization yield and the mechanical strength are lowered,
Not only is it unfavorable, but the thermal stability during molding is also poor. Further, a problem occurs even if there are too many components within the range of M _W = 2000 to 40,000. That is, 10% by area of the component
A pitch exceeding the above means that the content of the low-molecular component becomes small, and the fluidity required as the binder pitch and the kneadability with the aggregate coke become insufficient.

Therefore, the pitch containing 5 to 10 area% of the component within the range of M _W = 2000 to 40,000 has characteristics satisfying as the binder pitch. Binder pitch of the present invention, M _W is 150 exceeds the component in the range of less than 2000, preferably contains a component of both the components in the range of M _W = 2000~40000.

This is because the component has the effect of improving the fluidity required for the binder pitch and the kneading property with aggregate coke. Further, the binder pitch in the present invention more preferably has a peak of the molecular weight distribution of 2 with M _W = 230 and M _W = 8000.
It is preferably composed of only one peak.

This is because, when M _W has a peak at 230, the oil component and the low-molecular component that compose the peak have the highest fluidity, wettability with aggregate coke and kneadability required for the binder pitch. This is to effectively improve. When M _W has a peak at 8000, the polymer component forming the peak has other properties required for the binder pitch, that is, moldability during molding, thermal stability, and binder coke crystals after firing. This is because the properties and the carbonization yield are most effectively improved.

In the binder pitch for carbon material of the present invention, the quinoline insoluble content of the pitch is preferably 5 to 15% by weight, more preferably 7 to 13% by weight. This is because when the content is less than 5 wt%, the quinoline insoluble content is small, so that the bulk specific gravity of the carbon material of the final product is small and sufficient mechanical strength cannot be obtained.
This is because if it exceeds 15 wt%, the binder pitch becomes insufficient in the caking property and molding becomes impossible.

From the above reason, as a method of evaluating the binder pitch, the molecular weight (M _W ) distribution of the quinoline-soluble component of the binder pitch for carbon material is measured by gel permeation chromatography using quinoline as a solvent. The moldability and workability in the kneading process are predicted and evaluated by the amount of the component having M _W of 150 or less, and the carbonization yield as the binder pitch is determined by the amount of the component having M _W of 2000 to 40,000. Further, it is preferable to predict and evaluate the mechanical strength of the obtained carbon material, the thermal stability during molding, and the like.

The binder pitch in the present invention described above can be obtained, for example, by the following method. Coal tar containing 3 to 8 wt% of quinoline insoluble matter was distilled to obtain a softening point.
A soft pitch of 50 to 70 ° C. is obtained, and this soft pitch is subsequently heat treated to form a binder pitch.

The quinoline-insoluble matter contained in the above-mentioned coal tar is called free carbon, and when coal is carbonized, coal tar is 1000 to 1000 in the coke oven.
It was generated by receiving a thermal history of 1300 ° C. Generally, the higher the operating conditions of the coke oven, that is, the higher the temperature of the coke oven, the greater the amount of this free carbon produced.

[0036] When a quinoline insoluble content of less than 3 wt%, distillation of coal tar, quinoline-soluble component of the binder pitch obtained by heat-treating, 5 area content of ingredients within the range of molecular weight M _W is 2000 to 40,000 and becomes less than%, contrary to the quinoline insoluble content cases exceeds 8 wt%, of quinoline soluble matter of the resultant binder pitch, the content of the component in the molecular weight range of M _W is 2000 to 40000 is more than 10% by area.

Coal tar containing 3 to 8 wt% of quinoline-insoluble matter is distilled at 250 to 320 ° C. to distill off low molecular components in the coal tar to obtain soft pitch having a softening point of 50 to 70 ° C. obtain. Next, the soft pitch was heat-treated at a temperature of 350 to 450 ° C., at the same time the molecular weight M _W is to produce a polymer component of from 2000 to 40,000, to obtain a binder pitch was evaporated to low molecular weight components in soft pitch .

This heat treatment is performed with a binder pitch of M
50mm to ensure that _W does not contain ingredients below 150
It is desirable to carry out under a reduced pressure of Hg (absolute pressure) or lower, or by using steam distillation using steam. Heat treatment temperature
If it is less than 350 ° C., the molecular weight M _W of the binder pitch 20
The content of the component within the range of 00 to 40,000 is less than 5 area%, and the component having M _W of 150 or less remains in the binder pitch.

When the heat treatment temperature is higher than 450 ° C., the content of the component having a binder pitch molecular weight M _W within the range of 2000 to 40,000 exceeds 10 area%.

[0040]

EXAMPLES The present invention will be specifically described below based on Examples and Comparative Examples. In the examples and comparative examples, the softening point of pitch, the quinoline insoluble content and the fixed carbon content were measured based on JIS K 2425, and the quinoline soluble content of the pitch was measured by the method described above. went.

The bending strength of the obtained electrode piece, which is a carbon material, was measured by the three-point bending test method based on JIS R-7202, and the specific resistance was measured by the voltage drop method based on JIS R-7202. Went by. Example 1 Coal tar containing 3 wt% of quinoline-insoluble matter was distilled under reduced pressure [= 150 mmHg (absolute pressure)] at 300 ° C. to obtain soft pitch having a softening point of 60 ° C. and quinoline-insoluble matter of 6 wt%. Obtained.

The soft pitch was heat-treated under reduced pressure [= 20 mmHg (absolute pressure)] at 380 ° C. for 10 hours using a 20-liter autograve, and low molecular components were distilled off to obtain a binder pitch. The characteristics of the obtained pitch were as follows: softening point = 90 ° C., quinoline insoluble matter = 10 wt%, fixed carbon amount = 57 wt%. next,
The molecular weight distribution of the quinoline soluble component of the obtained pitch was measured.

The measurement results are shown in FIG. As shown in FIG. 1, the obtained pitch has peaks at M _W = 230 and M _W = 8000, and the molecular weight distribution having a peak at M _W = 8000 is M
It was found that _W was in the range of 2000 to 40,000. Also,
The content of the component M _W is in the range of 2,000 to 40,000 was 6.5 area% of the total.

Further, this pitch did not contain a component having M _W of 150 or less. This binder pitch and acicular coke were mixed and kneaded at a mixing ratio of {acicular coke: binder pitch = 7: 3 (weight ratio)}, and molded into an electrode piece shape (40 mmφ × 120 mm) at 1000 ° C. Then, the electrode piece was prototyped, and the bending strength and the specific resistance were measured.

As a result, the obtained electrode piece was
Degree = 270kgf / cm^Two, Resistivity = 80 × 10 ^-FourΩcm is enough characteristics
Had. (Example 2) Coulter containing 4 wt% of quinoline insoluble matter
Steamed under reduced pressure [= 150 mmHg (absolute pressure)] at 300 ° C.
Then, softening point of softening point is 64 ℃ and quinoline insoluble matter is 7wt%.
I got Ji.

The soft pitch was heat-treated at 385 ° C. for 10 hours under reduced pressure [= 20 mmHg (absolute pressure)] using a 20 l autograve to distill away low molecular components to obtain a binder pitch. The characteristics of the obtained pitch were as follows: softening point = 108 ° C., quinoline insoluble matter = 12 wt%, fixed carbon amount = 60 wt%. Next, the molecular weight distribution of the quinoline-soluble component of the obtained pitch was measured.

As a result, the obtained pitch is M_W= 230
And M_WA peak is seen at = 8000, M _WPeak at 8000
The molecular weight distribution it has is M_W= Must be in the range of 2000-40000
I understood. Also, M_WIs in the range 2000 to 40000.
The content of min was 8.8 area% of the whole.

Further, in this pitch, M_WIs 150 or less
Was not included. This binder pitch
Was kneaded with needle-like coke in the same manner as in Example 1 to form a mixture.
Molded and baked at 1000 ℃, prototype electrode piece, bending strength
And the specific resistance was measured. As a result, the resulting electrode peak
Bending strength = 280kgf / cm^Two, Resistivity = 75 × 10 ^-FourΩcm
Had sufficient characteristics.

(Embodiment 3) Same as Embodiment 2, the softening point is 64.
C., soft pitch having a quinoline insoluble content of 7 wt% was heat-treated at 385.degree. C. for 10 hours under a steaming condition using a 20-liter autograve. Steaming steam supply is 350g / hr
And The characteristics of the obtained pitch were: softening point = 106 ° C., quinoline insoluble matter = 11 wt%, fixed carbon amount = 59.5 wt%.

As a result of measuring the molecular weight distribution of the quinoline soluble component of the obtained pitch, peaks were observed at M _W = 230 and M _W = 8000, and the molecular weight distribution having a peak at M _W = 8000 was M _W.
= 2000 to 40,000, and the content of the components in this range was 7 area% of the whole. Furthermore, M _W
No component with a value of 150 or less was contained. This binder pitch was kneaded and molded with needle coke in the same manner as in Example 1 and fired at 1000 ° C. to make an electrode piece, and the bending strength and the specific resistance were measured.

As a result, the obtained electrode piece was
Degree = 290kgf / cm^Two, Resistivity = 80 × 10 ^-FourΩcm is enough characteristics
Had. (Comparative Example 1) The same softening point as in Example 1 was 60 ° C and no quinoline was added.
Using a soft pitch of 6 wt% in the melt, using a 20l auto-grave
At 300 ℃ for 1 hour under reduced pressure [= 30 mmHg (absolute pressure)]
Heat treated, softening point = 88 ℃, quinoline insoluble matter = 9.5wt%,
A pitch having a fixed carbon amount of 49 wt% was obtained.

As a result of measuring the molecular weight distribution of the quinoline-soluble component of the obtained pitch, peaks were observed at M _W = 230 and M _W = 8000, but the content of components having M _W in the range of 2000 to 40,000 was found. The amount was 0.5 area% of the whole. Further, this pitch did not contain a component having M _W of 150 or less. This binder pitch was kneaded and molded with needle coke in the same manner as in Example 1 and fired at 1000 ° C. to make an electrode piece, and the bending strength and the specific resistance were measured.

As a result, the obtained electrode piece had a bending strength of 50 kgf / cm ² and a specific resistance of 200 × 10 ⁻⁴ Ωcm, which was low in strength and large in specific resistance, and was not sufficient as an electrode. (Comparative Example 2) A soft pitch having the same softening point of 60 ° C. and quinoline insoluble content of 6 wt% as in Example 1 was heat treated under normal pressure at 350 ° C. for 10 hours using a 20 l autoclave, and a softening point = 75.
A pitch having a quinoline insoluble content of 9 wt% and a fixed carbon amount of 48 wt% was obtained.

As a result of measuring the molecular weight distribution of the quinoline-soluble component of the obtained pitch, peaks were observed at M _W = 230 and M _W = 8000, and the content of the components having M _W in the range of 2000-40000 was The total area was 5.1 area%. Further, this pitch contained 6.8 area% of the whole of the components having M _W of 150 or less.

This pitch is set in the same manner as in the first embodiment.
As a result of kneading with needle-like coke and a molding test, a large amount of tar vapor was generated during kneading, the kneading was insufficient, and a large amount of tar vapor was generated during molding, and molding was impossible. (Comparative Example 3) Coal tar containing 1 wt% of quinoline insoluble matter was distilled under reduced pressure [= 150 mmHg (absolute pressure)] at 300 ° C to obtain a soft pitch having a softening point of 70 ° C and quinoline insoluble matter of 2 wt%. Obtained. This soft pitch was heat-treated under reduced pressure [= 20 mmHg (absolute pressure)] at 380 ° C. for 10 hours using a 20 l autograve to distill away low molecular components to obtain pitch. The characteristics of the obtained pitch are as follows: softening point = 92 ° C., quinoline insoluble matter = 4
wt%, fixed carbon amount = 49 wt%.

As a result of measuring the molecular weight distribution of the quinoline-soluble component of the obtained pitch, peaks were observed at M _W = 230 and M _W = 8000, but the content of components having M _W in the range of 2000 to 40,000 was found. The amount was 1 area% of the whole. Further, this pitch did not contain a component having M _W of 150 or less. In the same manner as in Example 1, this pitch was kneaded with needle-shaped coke, molded, and fired at 1000 ° C. to make an electrode piece, and the bending strength and specific resistance were measured.

The electrode piece obtained had a bending strength of 60 kgf /
cm ² , specific resistance = 250 × 10 ^-4 Ωcm, the strength was low and the specific resistance value was large, which was not sufficient as an electrode. (Comparative Example 4) Coal tar containing 10 wt% of quinoline insoluble matter was distilled under reduced pressure [= 150 mmHg (absolute pressure)] at 300 ° C to obtain a soft pitch having a softening point of 85 ° C and a quinoline insoluble matter of 17 wt%. Obtained. This soft pitch was heat-treated under reduced pressure [= 20 mmHg (absolute pressure)] at 380 ° C. for 8 hours using a 20-liter autograve to distill away low molecular components to obtain pitch. The characteristics of the obtained pitch are as follows: softening point = 102 ° C, quinoline insoluble content =
The amount was 20 wt% and the fixed carbon amount was 65 wt%.

As a result of measuring the molecular weight distribution of the quinoline-soluble component of this pitch, peaks were observed at M _W = 230 and M _W = 8000, but the content of the components in the range of M _W = 2000-40000 was , Was 15% by area of the whole. Further, this pitch did not contain a component having M _W of 150 or less.
This pitch was kneaded and molded with needle coke in the same manner as in Example 1, but could not be molded due to insufficient pitch caking property.

[0059]

According to the present invention, when used as a raw material for producing a carbon material, the obtained carbon material has a large mechanical strength,
It becomes possible to obtain a binder pitch for carbon materials, which has a low electrical resistivity value, a large carbonization yield, and excellent moldability. Furthermore, the binder pitch moldability in the carbon material manufacturing process, and the obtained carbon material It has become possible to evaluate mechanical strength, etc. quickly and accurately by a simpler method.

[Brief description of drawings]

FIG. 1 is a graph showing an example of a molecular weight distribution of binder pitch according to the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikio Kunitake 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Chiba Works (72) Inventor Hideaki Okada 1 Kawasaki-cho, Chuo-ku, Chiba Kawasaki Steel Co., Ltd.Chiba Works

Claims (4)

[Claims] 1. The molecular weight (M _W ) distribution of the quinoline-soluble component of the binder pitch for carbon materials is measured by gel permeation chromatography (GPC) using quinoline as a solvent, and components having M _W of 150 or less are substantially analyzed. Not included, and M _W
But more than 2000, 40000 of the following ingredients containing 5-10%, balance M _W 150 exceeds, binder pitch for carbon materials, which is a component of less than 2000. 2. In the measurement of the molecular weight (M _W ) distribution, the peaks of the molecular weight distribution are M _W = 230 and M _W = 80.
The binder pitch for carbon materials according to claim 1, which is composed of only two peaks of 00. 3. The binder pitch for a carbon material according to claim 1, wherein the amount of the quinoline insoluble matter in the binder pitch for the carbon material is 5 to 15 wt%. 4. The molecular weight (M _W ) distribution of the quinoline-soluble component of the binder pitch for carbon material is measured by gel permeation chromatography using quinoline as a solvent,
A binder pitch for a carbon material, characterized in that the moldability when the pitch is used and the mechanical strength of the obtained carbon material are evaluated by the amount of the component having M _W of 150 or less and the amount of the component having M _W of 2000 to 40,000. Evaluation methods.