DE1646658A1 - Process for the production of objects of distinct shape from coal - Google Patents

Description

G. Wilhelm Beichei

Frankfurt / Mcdn-l

5455

Kureha Kagaku Kogyo Kabushiki Kaisha, Tokyo-Ιο, Japan

Process for the production of objects of pronounced shape from charcoal

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The invention relates to a method for producing objects of pronounced shape from carbon, wherein the Graphitization properties of the objects in an area from easy to graphize to difficult Graphitizability can be selected and the structural conditions range from vitreous to porous.

This is in particular formed from coal or shaped articles whose Graphitierungseigenschaften and microstructures extend over wide areas, said modified pitch types serving as raw materials for producing the λ items.

It is already known to produce objects or structures of pronounced shape from different types of coal. For example, vitreous types of coal are known, such as the so-called cellulosic carbon, manufactured by G.E.C., Ltd., England, the so-called glass coal, manufactured by Tokai Denkyoku Company, Ltd., Japan, and coal products, manufactured by Shigen Gijutsu Shiken-Jo, Japan, to theirs Manufacture Acetone Purfurol Resins Used as Starting Material will. Perner are other different types of coal

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or carbon products known, including porous Objects and threads. While these charcoal products have excellent properties, they are after difficult and time-consuming processes or require very expensive starting materials.

The object of the invention is to provide a simpler and less complex manufacturing process for these To create charcoal or carbon formed objects. The graphitization properties should be in one area from a light to a difficult graphite! - can be selected and the structure should be from vitreous to porous state. Furthermore should the products be uniform and homogeneous, including as raw materials Types of pitch that have been modified with little effort.

This object is achieved by the method according to the invention in that a modified pitch with a hydrogen / carbon atomic ratio of 0.2 to 0.6 and with a softening point of at least 170 ^° C. is produced, and that modified pitch is used from this as the main starting material Pitch an object of pronounced shape is produced and that this object is subjected to a charring and / or graphitization treatment in an inert gas atmosphere or instead is firstly subjected to an oxidation treatment and then in an inert gas atmosphere to a charring and / or graphitization treatment .

The details of the invention and the scope of application are to be elaborated in the following on the basis of exemplary embodiments of the subject matter of the invention to be caught "

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By "modified pitch" or "modified pitch" is meant all types of pitch obtained by heat treatment, by treatment with a dehydrating agent, for example ozone, oxygen, air, halogens and sulfur, or by a solvent extraction treatment of coal tar pitch, petroleum asphalt and others Tar and pitch types, which arise as industrial by-products, are extracted. These modified types of pitch are also characterized in that the hydrogen / carbon atomic ratio in them is between 0.2 and 0.6 and the softening temperature is 170 ^° C. or higher.

The "softening temperature" or the "softening point" is to be understood as the temperature at which a sample in the form of a fine powder of the order of magnitude of about 0.1 mm in a closed tube assumes a perfectly spherical shape, for which purpose a micro-melting point meter is used . Numerous types of modified pitch with a hydrogen / carbon atomic ratio of the order of 0.60 to 0,4b show softening points in the range 170-300 ^0C

Take pitch types with a hydrogen / carbon atomic ratio of 0.46 to 0.40 when heated in powder form do not have a distinctly molten state, but in many cases swell when heated when they were molded or cast in an inert gas atmosphere under pressure, the swelling being caused by the formation of a semi-seismic state and through the creation of Gases is caused. Even if the pitch types with a hydrogen / carbon atomic ratio of 0.4 to 0.2 do not have any pronounced molten state when in

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Form of powder to be heated, or no semi-molten Condition when they are heated in the form of a pressed structure, these types of pitch are still sufficient good sintering properties.

The described relationship between the hydrogen / carbon Atomic ratio and the softening point changes to a certain extent, depending on whether functional groups with high thermal reactivity are present in the modified pitch.

Modified pitches can be made by a number of types of processes. The following are some of these procedures to be discribed.

A. When dry distillation is carried out in an inert gas atmosphere, the distillation residue can be ^; . a temperature of 3 · -0 to 500 ⁰ C can be used as modified pitch with the properties described above.

B. If the pitch is blown with air during dry distillation, then you can use the distillation residue in a Temperaturbere eh from 3 ^ 30 to 430 ⁰ C.

In the modified one made by this process Unfortunately, no enrichment of the oxygen content could be determined.

C. In a process other than that described under A and B for the production of modified pitch with the treatment with chlorine gas is carried out. For example, if coal tar pitch in a Cül-Tgasatinosphere beginning with room temperature gradually is heated, then a modified one is obtained

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Pech Rait e no softening point in the range 170-300 ⁰ C, namely at a treatment up to a temperature of 150-270 ⁰ G. This modified pitch contains 5 to 15 $ chlorine.

It is also possible to use a combination of the items A and C or B and C, or any other of the methods described, either alone or together to use with other procedures.

D. A process with an ozone treatment at room temperature and an immediately subsequent air oxidation treatment up to a temperature of about 250 ° C. is particularly suitable for increasing the softening point and lowering the hydrogen / carbon atomic ratio of the types of pitch used as starting materials. Furthermore, a functional group which has oxygen with a high thermal reactivity is introduced into a modified pitch which already has the aforementioned properties. In this way one can very easily introduce oxygen up to an amount of about 30 ^σ β> into the pitch.

A single modified pitch or a mixture of different types of pitch is used to shape the material grind to a desired particle size or combination of different particle sizes. By compression molding lei the ground particles are pressed into a shape under a pressure of 100 to 3,000 kg / cm. A feature of this procedure is that the incorporation of an aggregate such as coke particles or a binder such as pitch does not necessary is. Additives such as coke and graphite can be used be added, especially when the softening point of bad luck is small.

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The form according to the invention can be carried out by injection or pressing in a syringe, compression mold or hollow form. In both cases, good results are obtained by adding about 10 -p or less alcohol or any alcohol to the modified Peeh another suitable liquid is added.

In a modified pitch having a softening temperature of 300 ⁰ C or less, the molding of the pitch is first performed _r, the pitch dried and then placed in air gradually to a temperature of 200 to 300 C, wherein the Temperaturzunähme between 0.1 and 3 ⁰ C per minute. The. The rate of rise of the temperature can be increased and the maximum treatment temperature in air can be decreased when the modified pitch has a higher softening temperature and particularly when the modified pitch has a thermally reactive puncture group. For larger objects, lower temperature rise rates are preferable.

Even with modified Peeharten with a softening temperature of 300 C or more or a codified pitch that does not have a specific softening temperature, but its hydrogen / carbon atomic ratio is 0.4 or greater, the heat treatment is preferably carried out in Air carried out if the manufactured objects are to have high strength and durability. At a Modified pitch with a quantitatively large thermally reactive functional group is heat hardening only by "heating in an inert gas atmosphere a sufficiently low rate of temperature rise possible, whereby the heating in air can be omitted. at a modified pitch with a softening point, the

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can not be determined exactly, and a hydrogen / carbon atom ratio from 0.2 to 0.4 is a heating in not necessary «

The charring and graphitization of those molded Items that need such treatment will at a rate of temperature rise of about 5 G per minute in an inert gas atmosphere following the • Heat treatment carried out in air.

The following are some general properties of the ™

Coal products specified, according to the invention Process can be produced.

1. Depending on the softening point of the modified pitch and the molding pressure, objects with a porosity in the range from δ to 60 % can be produced *

2. These products or objects generally have a high degree of hardness. The Shore hardness of an object made of carbide with a porosity of about 30 $> or less is ÖO to 130. If the object were subjected to a graphitization treatment (at 2,600 ° G), then the λ öhore hardness is 50 to 90 with a porosity from about 30 ^C A *

3. The specific bulk density of these articles is 0.7 to 1, fv * ■■ .- .. ■ ""'■ ... "■ -.

4 ,. The mechanical strength of these objects depends on the porosity and the specific bulk density. In alj ^ emeinor the strength at carbonized articles is LiOCH ui.ei lower at graphitized articles "rlt -JF a porosity 8-15 ⁰ A have a

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Flexural strength of 800 to 1 100 kg / cm, articles having a porosity of 15 to 30 i »a flexural strength of 400 to 800 kg / cm and objects having a porosity vo over 30 $ a flexural strength of 100 to 400 kg / cm.

Objects with a porosity 8-15 $> which have undergone at 6OQ ⁰ C heat treatment, have a

ρ flexural strength of 100 to 200 kg / cm and a Shore hardness from 100 to 130. '

5. Among the measured physical properties of these molded articles, the graphitizing properties gave the most surprising result. A shaped object for which a modified pitch is used as the starting material, which is produced according to the described process A at a temperature of over 450 ^° C. and is then subjected to process D, shows, for example with respect to X-rays, properties which are the properties of a slightly graphitized carbon material, although the modified pitch used as the starting material has an oxygen content of $ 15-25. In contrast, shows a shaped article, for which a modified pitch is used as starting material by the method B at a temperature of about 380 ⁰ C, is prepared with respect to X-rays characteristic of carbon materials, which are very difficult to graphitize although no oxygen can be detected analytically in the starting material.

To further explain these characteristics, the relationship between the modification process of the raw materials types of pitch used and the graphitization properties of the investigated carbon materials produced. This showed the following: -

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1. Modified types of pitch, which are produced according to the described method A, and modified types of pitch, according to method A and then according to a method for introducing a thermally reactive functional group or another method, so the Procedure C and D, or any of the other above Processes produced produce easily graphitized Carbon materials and carbon materials with poor graphical properties. "

2. Modified pitches obtained by Method B, Method C, Method D or by any other method be prepared in which a dehydrating agent is added is, and modified pitch types that are created by a combination produced by these processes yield carbon materials that are difficult to graphitize carbon materials to carbon materials with medium graphic properties. ~;

It is therefore easy möglieh to produce shaped carbon materials, which cover a range of carbon materials that are easy to graphitize, and which are difficult to graphitize and Λ ia having a porosity of 8 to 60. For this purpose, modified as a starting material for the articles pronounced .-. Pech shape types are used, the modified according to the different methods described for preparing pitches were prepared, and a hydrogen / carbon Atömverhältnis from 0.20 to 0.60 and a softening point of 170 ⁰ C or have more.

In the carbonization process step, the linear Shrinkage coefficient from $ 5 to $ 20, being in most is between $ 10 and $ 15.

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As the physical properties of the invention Manufactured carbon or carbon objects cover a wide area, find the invention Products have a wide range of applications.

The articles made according to the invention are more pronounced Low porosity shapes can be used, for example, as electrodes, electrolytic plates, structures - materials, fire-resistant materials and aggregates are used. In their manufacturing process, repeated heat curing, impregnation and renewed Heat treatments avoided. The formed articles with high porosity can, for example, as Electrodes for fuel cells, filter elements and as heat insulating materials are used.

An important feature of the invention is that one after the process according to the invention the possibility has, in a simple manner, carbon materials in the vitreous To produce state that can be easily graphitized or have difficult graphitizing properties, and to produce porous carbon materials that are easily graphitizable or have difficult graphitization properties, i.e. carbon materials that, according to their structure range from a vitreous state to a highly porous state and at the same time have a basic structure, that from easily graphitizable to difficult to graphitize Properties ranges »This feature extends the scope of application, both glass-like and porous carbon materials.

Another advantage is that for manufacturing of the coal materials Peoharten are used, which are dated can be described as extremely economical raw materials from an industrial point of view.

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To fully describe the invention, and the To show a wide range of applications, specific exemplary embodiments of the invention are given below.

The invention, however, is by no means limited to the following examples limited.

Example 1.

™ tar pitch produced by a softening point of 85 ⁰ C, Kawasaki Seitetsu (Kawasaki Iron and Steel), Japan, 60 minutes dry distilled at 380 ⁰ C for. Then, 20 g of the extraction substances which remained when the η-hexane-soluble components were removed from the residue of the dry distillation were dissolved in chloroform. For oxidation, air with ozone was passed through the solution at room temperature. After removing the chloroform, the remaining substance was ground. The hydrogen / carbon atomic ratio of this substance was 0.43.

This pitch-like substance was produced at a pressure of g

400 kg / cm pressed into a Seheibe with a diameter of 20 mm and a thickness of 10 mm. The disk was heated in air to a temperature of 320 ^° C., the temperature increase being 2 ^° C. per minute.

Thereafter, the · object in a nitrogen atmosphere was placed and heated to 1 000 ⁰ G at a temperature rising rate of 5 ° C per minute.

The item heat-treated in this way was very uniform and was mirror-like after polishing Surface. The remaining properties were as follows:

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Shore hardness (Hs): 100 - 115

Porosity: 17 °

Shrinkage: 15 ^

Specific debris weight: 1, '4.

Carbonization yield: 87 i °

Flexural strength: 600 kg / cm

This object was graphit is iert by heating to a temperature of ^{2,800 0} C in an "inert gas. The resulting object has the following properties:

Shore hardness (Hs): 68.

Porosity: 16 ^

"- 2 flexural strength: 300 kg / cm

Specific resistance: 7.0 · 10 0hm »cm.

The Teränderungen the lattice distances that are by the heat treatment at temperatures of 4600 ⁰ C and more produced, were the same as easily graphitizable carbon materials and amounted to 3.365 α for an object that has been heat-treated at a temperature of 2800 ⁰ C.

Example 2

A polyvinyl chloride powder was heat-treated in Sfcickstoffgas at a temperature from 400 to 430 ⁰ G. The pitch-like substance produced had a softening point of 195 to 202 ^° C. This powdery substance, used as the starting material, was spread out as well as possible and heated ^{to 200 ° C. for oxidation in air at a rate of temperature increase of 2 to 3 °} C. per minute . A pitch with a hydrogen / carbon atomic ratio of 0.48 was obtained.

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This pitch was ground and then at a pressure of 450 kg / cm to a disc with a diameter of 20 mm and pressed to a thickness of 4 mm. This window became the same Subject to process steps that are already described in Example 1 before the graphitization step. Of the article formed in this way was uniform and could be polished to a mirror-like surface. The following properties were measured:

Shore hardness (Hs): 108 τ. 120 Porosity: 16 Io Shrinkage: 20 i » Specific bulk weight: 1.42 Flexural strength: 800 kg / cm Example 3

A coal pitch with a softening point of 85 ⁰ G, manufactured by Kawasaki Seitetsu (Kawasaki Iron and Steel), Japan was dry-distilled at 380 ⁰ C. The resulting powdery residue was exposed to ozone at room temperature and then heated up to. oxidized a temperature of 200 ⁰ G in air. A first pitch material was created in the process.

The chloroform-insoluble constituents of the coal pitch of Kawasaki Seitetsu were heated in powder form for oxidation in an atmosphere of air at 200 ⁰ C. A second material was created in the process.

The first and second materials were mixed in a weight ratio of 1: 3 and the mixture was ground, whereby a pitch mixture with an average hydrogen / carbon atomic ratio of 0.50 received. These

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Mixture was at a pressure of 400 kg / cm into one Brought an object of distinct form and then the same Subject to procedural steps that were already described in Example 1 are described prior to the graphitization step. The properties of this subject were the following!

Shore hardness (Hs): 115-125 Porosity: 15 1o Shrinkage: £ 10 Specific debris weight: 1.50 Carbonization yield: $ 89> B e ge strength s 950 kg / cm Example 4

Coal pitch of the same kind as in Examples 1 and 3 having a softening point of 85 ⁰ C was dry-distilled at 380 ⁰ G for 60 minutes. After adding 5 ^c ß> tetramethylthiuram disulfide, the ^{residue was heat-treated for one hour at 300 °} C. and then ground. A pitch with a hydrogen / carbon atomic ratio of 0.45 was obtained.

This pitch was at a pressure of 150 kg / cm in a Disc with a diameter of 20 mm and a thickness of Pressed 10 mm. This disc subsequently became the same Process steps are exposed that have already been carried out in example t. are described prior to the graphitization step. Who are formed disc was uniform and could be polished to a specular surface. The disc had the following properties:

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Shore hardness (Hs): 110-125 Porosity: 16 # Shrinkage: £ 20 Specific debris weight: 1.45 Flexural Strength: η 600 kg / cm Example 5

Coal pitch having a softening point of 85 ° C, manufactured by Kawasaki Se.itetsu, Japan, was dry distilled for 30 minutes at 380 ⁰ C, "The residue was ground and exposed to chlorine gas for 30 minutes at room temperature. The resulting pitch had a hydrogen / carbon atom ratio of 0.41.

"P

This pitch was pressed at a pressure of 300 kg / cm in the same manner and formed y as it was already described in connection with Example. 1 It was then subjected to the same process steps that are described in Example 1 before the graphitization step.

The article thus formed was uniform and had a reflective surface after polishing.The properties of the item were as follows:

Shore hardness (Hs): 105-120 Porosity: 20 i> Shrinkage: Specific debris weight: 1.40 Flexural strength: 350kg / cm ⁴

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-Example 6

The starting material used was a pitch which occurs as a by-product in the petroleum naphtha cracking process and has a softening point of 195 to 205 ^° C. and a hydrogen / carbon atomic ratio of 0.54. This pitch was ground and then pressed at a pressure of 300 kg / cm into a disc having a diameter of 20 mm and a thickness of 5 mm.

This disk was heated in air with a temperature increase of 1 to 2 ^° C. per minute to 330 ^° C. and then heat-treated in an inert gas atmosphere by heating to 1,000 ^° C. with a temperature increase of 5 ^° C. per minute.

The formed article showed good uniformity and had specular surfaces after polishing. His Features were the following:

Shore hardness (Hs): 98-112 Porosity: 15 1 ° Shrinkage: Ib <$> Specific bulk weight: 1.46 Flexural strength: 600 kg / cm

35 # graphite powder was added to this pitch material. This mixture was pressed at a pressure of 500 kg / cm into an object which was then ^{heated to 300 ° C. in air at a temperature increase of 0.5 °} C. per minute and then by heating up to was graphitized at a temperature of 2800 ⁰ C in nitrogen gas. This article had easily graphitizable properties as determined by X-rays and had the following properties:

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Shore hardness (Hs): Porosity: Flexural strength: Specific resistance:

Example 7

50
.16 <? O

290 kg / cm 6 x 10 ^-4 ohm.cm.

Coal pitch with a softening point of 65 ° C from Kawasaki Seitetsu, Japan, was ground to a fine powder and heated in this form to 250 ° in a chlorine gas atmosphere.

The resulting material had a hydrogen / carbon atomic ratio of 0.38 and up to a temperature of 360 ^° C. no softening point could be found.

This material was then ground into a fine powder, which was then subjected to a pressure of 400 kg / cm the same object was pressed as in Example 4.

With a temperature increase of 2 to 3 ^° C. per minute, ^{this object was heated to 500 °} C. in nitrogen gas and then heat-treated by being treated with a tempera

increase of 5 was brought.

0 per minute to a higher temperature

The resulting item had the same external appearance like the corresponding items in the previous examples and had the following properties:

Shore hardness (Hs): 75-85

Porosity: $ 20>

Shrinkage: 18 #

Specific debris weight: 1 _f 35

Carbonization yield: $ 70

Flexural strength:

400 kg / cm '

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Example 8

The chloroform-insoluble component of the coal pitch of Kawasaki Seitetsu, Japan, was used as the starting material.

This material was well spread in powder form, so that it came into contact with air and oxidized by heating to 220 ⁰ C. A pitch with a hydrogen / carbon atomic ratio of 0.50 was obtained.

This pitch was ground into a fine powder which, at a pressure of 450 kg / cm, formed a disk with a diameter of 20 mm and a thickness of 7 mm was pressed. The disc was heat treated under the same conditions as it is given in Example 5. The resulting article had an external appearance similar to that of the corresponding articles of the previous examples and had the following properties:

Shore hardness (Hs): 115-128 Porosity: 13 # Shrinkage: 9 * Specific bulk weight: 1.50 Carbonization yield: 88 i » Flexural strength: 850 kg / cm ² Example 9

500 g of coal tar pitch having a softening point of 85 ⁰ C, 90 minutes Dry distilled at 400 ⁰ C, was blown .wobei the pitch with air. A modified pitch with a softening point of 238 to 245 ^° C. and a hydrogen / carbon atomic ratio of 0.46 was obtained. This pitch was ground and at a pressure of

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400 kg / cm molded into an object. The article was heated in air at a temperature increase of 0.3 ° C per minute to 300 ⁰ C. This was followed by further heating to 2 800 ⁰ C with a temperature rise of 5 ° C per minute. A disc-shaped object with a Durehmesser of 40 mm and a thickness of 10 mm had a Shore hardness of 95, a porosity of 12 ° / o and a flexural strength of 600 kg / cm ^2.

The grid spacing was 3.39 ft, to determine which the X-ray 002 diffraction line was used. The specific one Resistance was 3 x 10 ohm cm. The end product was a carbon material that was difficult to graphize.

Example 10

Petroleum asphalt was dry-distilled at 390 ⁰ C with quenching air. The resulting material was ground and heat treated in a chlorine gas atmosphere at a temperature up to 250 ^{° C.} The modified pitch thus obtained had an hydrogen / carbon atomic ratio of 0.42 and a softening point which could not be accurately determined.

This pitch was pressed at a pressure of 300 kg / cm pronounced in an object form, which was then heated in air at a temperature increase of 1 ⁰ C per minute to 300 ⁰ O and in nitrogen to 2 800 ⁰ C. The carbon or carbon material obtained in this way had a Shore hardness of 68, a porosity of 48 ^c / o _t, a flexural strength of 78 kg / cm and a specific resistance of 13 · 10 ohm · cm. Furthermore, it was found with X-rays that the material had difficult to graphitize properties.

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Claims (3)

Claims 1. A method for producing objects of pronounced shape from carbon, in which the graphitization properties of the objects can be selected in a range from easy graphitizability to difficult graphitizability and the structural states range from vitreous to porous, characterized in that a modified pitch with a hydrogen / carbon atomic ratio of 0.2 to 0.6 and with a softening point of at least 170 ^° C., that an object of pronounced shape is formed from this modified pitch, which is used as the main starting material, and that this object is in an inert gas atmosphere is exposed to a carbonization and / or graphitization treatment or instead is first exposed to an oxidation treatment and then in an inert gas atmosphere to a carbonization and / or graphitization treatment. 2. The method according to claim 1, characterized in that the modified pitch in the powdery state is molded or pressed into the article of pronounced shape. 3. The method according to claim 1 or 2, characterized in that the modified pitch by at least one treatment, such as heat treatment, solvent extraction or treatment with oxygen, Ozone, a halogen or sulfur from coal tar pitch, petroleum anphalt, or any other than industrial By-product occurring pitch or tar is produced. 209818/0803