Micronized modified granular carbon material and method for producing same

Abstract

The present invention relates to a finely divided particulate carbon material, a method for producing the same and uses thereof.

Description

[Technical Field]

[0001] This invention relates to micronized modified granular carbon materials, methods for producing them, and uses thereof. [Background technology]

[0002] Micronized and modified granular carbon materials are used in many application fields. These range from use as black colorants to use as fillers in polymers, such as elastomers, thermoplastics, or thermoplastic elastomers. Such carbon-based materials may be, for example, carbon black, i.e., materials with a relatively high proportion of carbon. Other granular carbon materials are obtained by regenerating raw materials. Compared to carbon black, such granular carbon materials have a somewhat lower proportion of carbon but exhibit interesting properties due to their high degree of functionalization. Starting materials of particular interest for the production of granular carbon materials based on regenerated raw materials are starting materials that can be dissolved completely or partially, such as sugars, starches, or lignins. Such completely or partially soluble starting materials based on regenerated raw materials can be converted into granular carbon materials by a precipitation process. Precipitation processes for the production of dissolved granular carbon materials are well known to those skilled in the art.

[0003] For example, lignin-based granular carbon materials can be obtained, for instance, from lignin dissolved in liquid sodium hydroxide by precipitation by introducing an acidic gas such as CO2 or H2S, or by adding an acid such as H2SO4. Examples of this prior art are cited in International Publication Nos. 2006031175, 2006038863, or 2009104995.

[0004] Furthermore, lignin-based granular carbon materials can be obtained by precipitation, accompanied by simultaneous stabilization, from lignin dissolved in a base, such as liquid sodium hydroxide, by raising the temperature, for example, to hydrothermal carbonization conditions. Examples of this prior art are described in International Publication No. 2016 / 020383 or International Publication No. 2017 / 085278. Methods for precipitation by introducing acidic gas, adding acid, or raising the temperature can be further combined.

[0005] In the production of granular carbon materials, adjusting certain process parameters can broaden the possibilities for influencing the resulting particle size (i.e., the size of the resulting aggregate, which can be constructed from primary particles) or particle size distribution, as well as surface parameters, particularly the specific surface area (which is also used as a measure of primary particle size).

[0006] Particle size or particle size distribution can be quantified, for example, by sieve analysis or laser diffraction. For example, sieve analysis of dry granular carbon material may be performed according to DIN 66165. Laser diffraction may be performed, for example, for granular carbon material dispersed in water, according to ISO 13320.

[0007] The primary particle size may be quantified by methods for measuring specific surface area, such as BET measurement or STSA measurement. Here, BET measurement calculates the sum of the outer and inner surface areas, while STSA measurement calculates only the outer surface area. Appropriate measurement methods are given, for example, in ASTM D 6556-14. When selecting the degassing temperature, it should be noted that it should be set to a value of approximately 150°C for the inspection of granular carbon materials.

[0008] It is well known that the average size or specific surface area of ​​primary particles affects the properties of materials manufactured using granular carbon materials, such as rubber products manufactured by compounding granular carbon materials with elastomers accompanied by subsequent crosslinking. For example, the wear characteristics of rubber products differ depending on whether granular carbon materials with a larger or smaller BET surface area are used. The situation is similar for mechanical properties such as tensile strength. A larger BET surface area correlates with a larger tensile strength and lower wear. Here, when granular carbon materials are used, at least 5m 2 / g, preferably at least 8m 2 / g, more preferably at least 10m 2 / g, more preferably at least 15m 2 A specific surface area value of 1 / g or higher is often required to obtain high-quality rubber products.

[0009] However, a drawback of known granular carbon materials obtained by precipitation of raw materials based on the regeneration length of lignin-based granular carbon materials, in which the raw material, particularly all or part of it, is the unpleasant odor emanating from the granular carbon material itself, released during processing of the granular carbon material, and / or from materials containing the granular carbon material. This severely limits the possible applications of granular carbon materials, but it is in itself very interesting.

[0010] Unpleasant odors in lignocellulosic materials are particularly caused by the thermal or chemical decomposition processes of lignin, hemicellulose, and cellulose, as well as other wood components (e.g., resins), which are formed during wood processing.

[0011] Compounds that produce an unpleasant odor include sulfur-containing substances such as dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, or dimethyl tetrasulfide, or phenolic substances such as phenol, guaiacol, or ethylguaiacol.

[0012] Furthermore, various volatile organic compounds are released. Volatile organic compounds, also known as VOCs, include volatile organic substances that easily evaporate or are already present as gases at low temperatures such as room temperature. Volatile organic compounds VOCs are already present in wood materials and are released from them during processing, or, according to current knowledge, they are formed by the decomposition of fatty acids, either becoming the decomposition products of wood. Typical conversion products that occur during processing are, for example, higher aldehydes or also organic acids. In particular, organic acids result as decomposition products of the cellulose, hemicellulose and lignin of the wood components, and most alkanoic acids or aromatic acids such as acetic acid, propionic acid, hexanoic acid, etc. are formed. Aldehydes are formed from the basic building blocks of cellulose or hemicellulose during hydrolysis processing. Thus, for example, aldehyde furfural is formed from the monosaccharides and disaccharides of cellulose and hemicellulose respectively, while aromatic aldehydes can be released during the digestion of the partial hydrolysis of lignin. Other aldehydes released are, inter alia, higher aldehydes, hexanal, pentanal or octanal.

[0013] Methods for the odor reduction of lignin-based granular carbon materials are known in the prior art. On the one hand, these depend, for example, on the preliminary purification of lignin by an extraction process (International Publication No. WO 2013 / 101397), an enzymatic catalytic reaction (German Patent Application Publication No. DE 10 2006 057566), a treatment using an oxidizing component including subsequent washing (German Patent Application Publication No. DE 10 1013 001678), on the other hand, for example, on the treatment of black liquor by an evaporation process, a treatment using a reducing agent or an oxidizing agent or also a chlorination reaction and a high-temperature treatment. However, such methods require the treatment of relatively large amounts of material or they involve the use of chemicals, which is disadvantageous from the perspective of both equipment and financial costs.

[0014] A method for treating lignin carbonized with hot water at high temperatures is known, for example, from European Patent No. 3053929. In European Patent No. 3053929, the lignin carbonized with hot water is stabilized, for example in activation, preferably under an inert gas, for the purpose of final treatment. Hydrothermal carbonization is carried out at a temperature between 150°C and 300°C, preferably between 150°C and 250°C. Stabilization is carried out at a suitable temperature, which is at least 30°C higher than the hydrothermal carbonization temperature. The stabilization temperature is between 200°C and 700°C, preferably between 300°C and 600°C, ideally between 500°C and 600°C. Thus, the lowest stabilization temperature of 330°C is the resulting hydrothermal carbonization temperature of 300°C, and the stabilization temperature of 280°C is the resulting hydrothermal carbonization temperature of 250°C. Here, the heating rate is between 0.1 and 20°C / min. During the process, gases (primarily oxygen and hydrogen) are removed from the material, preferably under reduced pressure during processing. The purpose of this heat treatment is to stabilize the carbonized lignin with hot water so that it is prepared for final processing, preferably activation, in order to produce activated carbon.

[0015] A method for reducing wood odor at high temperatures is known, for example, from European Patent No. 3170635. In this process, long wood chips having a length between 150 and 200 mm, a width between 15 and 20 mm, and a thickness between 0.5 and 2 mm are roasted at a temperature between 150°C and 300°C in an oxygen-poor or oxygen-free atmosphere for a duration of 1 to 5 hours. The mass loss is between 10 and 30%.

[0016] Therefore, it would be desirable to provide a method that enables the reduction of odors emitted from the granular carbon material itself, emitted during the processing of the granular carbon material, and / or emitted from materials containing the granular carbon material, preferably by treating the already obtained granular carbon material without using additional processing chemicals. In this way, costs and burdens can be reduced from the perspective of equipment, while at the same time the amount of material to be processed is decreased. However, another requirement of such a process is that the desirable properties of the granular carbon material, such as particle size or particle size distribution, or primary particle size or specific surface area, must not be lost during the odor reduction treatment.

[0017] However, another disadvantage of known granular carbon materials, especially lignin-based granular carbon materials, obtained by precipitation of completely or partially dissolved starting materials, for example based on the regeneration of raw materials, is their high polarity. This severely limits the possible applications of granular carbon materials, which are otherwise very interesting in themselves, especially when used as additives, reagents or fillers in materials with significantly different polarities.

[0018] Therefore, it would also be desirable to provide a method by which the polarity of the granular carbon material can be selectively adjusted, preferably by treating the already obtained granular carbon material. In this way, costs and burdens can be reduced from the perspective of equipment, while at the same time the amount of material to be processed is decreased. However, another requirement of such a method is that the desirable properties of the granular carbon material, such as particle size or particle size distribution, or primary particle size or specific surface area, must not be lost during the treatment for adjusting the polarity.

[0019] Also, since the granular carbon material is already a valuable product, the loss of material must not be excessive.

Prior Art Documents

Patent Documents

[0020]

Patent Document 1

[0021] [Non-Patent Document 1] Determination of surface- accessible acidic hydroxyls and surface area of ​​lignin by cationic dye adsorption; Bioresource Technology, 2014, 169: pages 80-87 [Overview of the Initiative] [Problems that the invention aims to solve]

[0022] Therefore, the present invention aims to provide a corresponding granular carbon material, as well as a method for producing the granular carbon material described above. [Means for solving the problem]

[0023] This objective is achieved by the subject matter defined in the claims. Preferred and further embodiments of the present invention derive from the embodiments given in the further claims and the following detailed description.

[0024] More specifically, the first subject matter of the present invention is, It is above 0.20 Bq / g carbon, but lower than 0.45 Bq / g carbon. 14 C content, D50 with a particle size distribution of less than 500 μm and greater than 0.5 μm, OH group density of at least 0.05 mmol / g and at most 0.4 mmol / g A granular carbon material having, The solubility of granular carbon material in alkaline liquids is less than 25%. It is a granular carbon material.

[0025] Another subject of the present invention is a method for producing granular carbon material according to the present invention, comprising at least two process steps, wherein a different granular carbon material pCM is prepared, which corresponds to a precursor of the granular carbon material according to the present invention, and which is subsequently modified in a second process step by heating under a gaseous atmosphere, thereby obtaining the granular carbon material according to the present invention, which is preferably odor-reduced.

[0026] Another subject of the present invention is the use of granular carbon material as an additive in polymer mixtures, particularly rubber mixtures such as elastomer mixtures.

[0027] Another subject of the present invention is a vulcanizable rubber composition comprising at least one type of rubber and at least one type of filler component, wherein the filler component comprises at least granular carbon material according to the present invention.

[0028] Another subject of the present invention is a vulcanizable rubber composition that can be obtained by vulcanization of a vulcanizable rubber composition and has a swelling of less than 25% after 7 days in an alkaline liquid. [Modes for carrying out the invention]

[0029] The method of the present invention enables the production of finely granular carbon material produced from starting materials based on the regeneration length of the raw materials, with reduced odor and / or reduced OH groups (i.e., reduced polarity). As mentioned above, such granular carbon material is another subject of the present invention.

[0030] A distinctive feature of the method according to the present invention is that, for example, in the first process step, finely milled granular carbon material (hereinafter referred to as pCM) is preferably obtained, and its odor is reduced in the second process step, thereby obtaining odor-reduced pCM.

[0031] A characteristic feature of the method according to the present invention is that, for example, in the first process step, a finely granulated carbon material (hereinafter referred to as pCM) is obtained, and in the second process step, its OH group density (particularly on the surface of the material) is reduced, preferably adjusted, thereby obtaining pCM with reduced OH groups.

[0032] The method according to the present invention also makes it possible to obtain pCM with reduced odor and reduced OH group density, preferably with adjusted OH group density. In this regard, the second process step can be combined with odor reduction and reduction, preferably adjustment, of OH group density. Hereinafter, modified pCM should be understood as odor-reduced pCM or pCM with reduced OH groups, or pCM with reduced odor and reduced OH groups. Modified pCM or refined modified pCM thus corresponds to the granular carbon material according to the present invention and is obtained after the second process step. Refined pCM or pCM (both unmodified) thus corresponds to the precursor of the granular carbon material of the present invention and is obtained after the first process step and used in the second process step.

[0033] According to the present invention, the refined pCM is obtained in a first process step, preferably in the presence of a liquid, particularly preferably in the presence of water, and converted to modified pCM in a second process step, preferably in a gaseous atmosphere. According to the present invention, the separation of the liquid from the refined pCM is preferably performed between the first and second process steps.

[0034] Both the granular carbon material (modified pCM) and its precursor (pCM) according to the present invention are, in the context of the present invention, preferably also referred to as “refined.” The term “refined” is hereafter defined as a function of the BET surface area, STSA surface area, and D50 of the particle size distribution, respectively. Particularly preferably, “refined” in the sense of the present invention means that each granular carbon material has a D50 (D50 value) of a particle size distribution of less than 500 μm and greater than 0.5 μm. This refinement is also referred to as PSD refinement, as will be defined hereafter.

[0035] As already mentioned above, the granular carbon material according to the present invention is also preferably referred to as “modified” granular carbon material or modified pCM in the context of the present invention. In this sense, the term “modified” means that the carbon material is obtained from a finely milled granular carbon material pCM used as a different starting material from the granular carbon material according to the present invention. The granular carbon material according to the present invention differs from the finely milled granular carbon material pCM used as a starting material pCM in that it can be obtained by heating the starting material in a gaseous atmosphere. By heating, the modification mentioned above is achieved. In the context of the present invention, the granular carbon material according to the present invention is also preferably referred to as finely milled modified granular carbon material. The above statements apply cumulatively in this respect.

[0036] According to the present invention, the morphology of the micronized pCM changes only slightly in the second process step. Thus also, it is characteristic of the method and of the granular carbon material according to the invention that the micronization of the modified pCM has already substantially been achieved after the first process step. Thus, the second process step of the present invention is configured such that the micronization of the pCM changes hardly at all, and substantially only the odor of the micronized pCM is reduced and / or the OH group density of the micronized pCM is reduced or adjusted.

[0037] The micronized pCM after the first process step has at least 5 m 2 / g, preferably at least 8 m 2 / g, more preferably at least 10 m 2 / g, even more preferably at least 15 m 2 / g, particularly preferably at least 20 m 2 / g, even more preferably at least 30 m 2 / g, particularly at least 35 m 2 / g or more BET surface area has been shown to be advantageous. Advantageously, the BET surface area is at most in the order of 200 m 2 / g, preferably at most 180 m 2 / g, more preferably at most 150 m 2 / g, particularly preferably at most 120 m 2 / g. In the following, the micronization described in terms of BET surface area is referred to as BET micronization.

[0038] Advantageously, the BET surface area of the micronized pCM differs from its STSA surface area by at most only 20%, preferably at most 15%, more preferably at most 10%. Thus, the pCM preferably has only a low porosity. As an alternative method for measuring the BET surface area, the STSA surface area may also be used. In the following, the micronization described in terms of STSA surface area is referred to as STSA micronization.

[0039] Furthermore, it has been shown to be advantageous if the refined pCM has a particle size distribution D50 of less than 500 μm, preferably less than 250 μm, more preferably less than 100 μm, and particularly preferably 50 μm after the first process step. Advantageously, the particle size distribution D50 of the refined pCM is greater than 0.5 μm, more preferably greater than 1 μm, particularly preferably greater than 5 μm, and even more preferably greater than 10 μm. D50 means that 50% of the particles are smaller than the indicated value. Hereinafter, refinement described in terms of PSD will be referred to as PSD refinement.

[0040] Therefore, the miniaturization of miniaturized pCM and modified pCM may be described by their PSD miniaturization and / or BET miniaturization and / or STSA miniaturization.

[0041] One configuration of the method according to the present invention is characterized by the following: - In the first process step, the refined pCM is obtained in the presence of a liquid. - It is converted to reformed pCM in a gas atmosphere in the second process step, - Between the first and second process steps, the liquid is separated from the refined pCM. - The refinement of the modified pCM after the second process step is up to 5 times smaller than the refinement of the refined pCM before the second process step, and / or - Compared to the odor of the refined pCM before the second process step, the odor of the modified pCM after the second process step is reduced, and / or - The OH group density of the modified pCM after the second process step is reduced compared to the OH group density of the refined pCM before the second process step.

[0042] The refinement of pCM decreases by up to 5 times, preferably up to 4 times, 3 times, 2.5 times, 2 times, 1.75 times, 1.5 times, 1.4 times, 1.3 times, 1.2 times, and 1.1 times, during the second process step.

[0043] A decrease in miniaturization means the following: - The D50 particle size distribution of the modified pCM is up to 5 times, preferably up to 4 times, 3 times, 2.5 times, 2 times, 1.75 times, 1.5 times, 1.4 times, 1.3 times, 1.2 times, 1.1 times greater than the D50 particle size distribution of the refined pCM, and / or - The BET surface area of ​​the modified pCM is up to 100%, preferably up to 5 times, preferably up to 4 times, 3 times, 2.5 times, 2 times, 1.75 times, 1.5 times, 1.4 times, 1.3 times, 1.2 times, 1.1 times, smaller than the BET surface area of ​​the refined pCM, and / or - The STSA surface area of ​​modified pCM is up to 100%, preferably up to 5 times, preferably up to 4 times, 3 times, 2.5 times, 2 times, 1.75 times, 1.5 times, 1.4 times, 1.3 times, 1.2 times, 1.1 times, and is smaller than the STSA surface area of ​​refined pCM.

[0044] Preferably, the coefficient by which the BET surface area or STSA surface area decreases in the second process step is smaller than the coefficient by which the D50 of the particle size distribution increases in the second process step.

[0045] Furthermore, it was shown to be advantageous when the refined pCM after the first process step has an ash content of less than 15% by mass, preferably less than 12% by mass, 10% by mass, 8% by mass, 6% by mass, 5% by mass, 4% by mass, 3% by mass, or 2% by mass. Advantageously, the ash content of the refined pCM is greater than 0.25% by mass, preferably greater than 0.5% by mass, and more preferably greater than 0.75% by mass.

[0046] Furthermore, the finely milled pCM preferably exhibits a carbon content of 40 to 80% by mass (mass%), more preferably 50 to 80% by mass, and more preferably 60 to less than 80% by mass (relative to the ash-free dry material (content of the ash-free dry material)).

[0047] The finely milled pCM further exhibits an OH group density of preferably at least 0.1 mmol / g, preferably at least 0.15 mmol / g, particularly preferably at least 0.2 mmol / g, and up to 0.6 mmol / g, preferably up to 0.55 mmol / g, and particularly preferably up to 0.5 mmol / g.

[0048] The refined pCM is more preferably at least 1 OH / nm 2 BET surface area, preferably at least 1.5 OH / nm 2 BET surface area, particularly preferably at least 1.75 OH / nm 2 BET surface area, and a maximum of 15 OH / nm 2 BET surface area, preferably up to 12 OH / nm 2 BET surface area, particularly preferably up to 10 OH / nm 2 This shows the OH group density of the BET surface area. OH group density of the material surface (OH / nm) 2 In addition, measurements (in both mmol / g) were performed by Sipponen et al. (Determination of surface-accessible acidic hydroxyls and surface area of ​​lignin by cationic dye adsorption; Bioresource Technology, 2014, 169: pp. 80-87).

[0049] A preferred embodiment of a first process step for obtaining a miniaturized pCM is described below. In the context of the present invention, it is not important whether this first process step is performed immediately before the second process step, or whether this first step is performed significantly earlier than the second in terms of time (for example, so that the pCM from the first step is manufactured separately and then stored or transported before being subjected to the second step).

[0050] Preferably, the refined pCM is obtained in the first process step by precipitation of the starting material, which is whole or partially dissolved in a liquid.

[0051] For this purpose, the starting materials are preferably dissolved in whole or in part in a liquid, preferably in water, before the first process step. More preferably, the dissolved starting materials before the first process step consist of more than 50%, preferably more than 60%, 70%, 75%, 80%, or 85% sugars (carbohydrates), starch, or lignin.

[0052] The sugar content will be measured according to the TAPPI T 249cm-00 guidelines.

[0053] The measurement of starch content will be carried out in accordance with the TAPPI T 419 guidelines.

[0054] The measurement of Klason lignin content will be carried out according to the TAPPI T222 ohm-02 guidelines. The measurement of acid-soluble lignin content will be carried out according to the TAPPI T250 UM 250 guidelines. In the following, the sum of Klason lignin and acid-soluble lignin will be referred to as the lignin content.

[0055] Lignocellulose-containing liquids suitable as, for example, starting materials, consequently result in waste in the pulp industry, where large quantities of wood are processed. Depending on the wood processing method, it is produced in large quantities as hydrolyzed lignin, usually as Kraft lignin dissolved in black liquor, or as lignin sulfonate. Depending on the pH value in each processing method, the hydrogen atoms in the hydroxyl groups typical of lignin may be replaced in proportion to the metal cations. Strictly speaking, lignin sulfonate is already a chemical derivative of lignin, as it exhibits additional sulfonate groups introduced during processing.

[0056] Therefore, in one embodiment of this method, black liquor is used as a lignocellulose-containing liquid used as a starting material. Black liquor is a lignin-containing liquid obtained as a wastewater result in the alkaline fragmentation process of biomass, for example, in the KRAFT process or the hydroxide process. The pH value of black liquor is usually in the alkaline range, with a pH of 12-14. In addition to lignin, black liquor may further contain organic or inorganic components. A characteristic of black liquor is that the proportion of lignin in the organic dry material exceeds 50%, particularly exceeds 60%, or even exceeds 70%, and is therefore significantly higher than the proportion of lignin present in woody biomass, which is 15%-35%.

[0057] When the starting material consists of more than 50% lignin, the refined pCM is preferably obtained by precipitation of lignin, either whole or partially, dissolved in a liquid, by introduction of an acidic gas and / or by addition of an acid and / or precipitation. Such methods are generally known to those skilled in the art and are described in International Publication No. 2006031175, International Publication No. 2006038863, or International Publication No. 2009104995. Advantageously, these methods are controlled so that, after the first process step, refined pCM having the particle size distribution, BET surface area, and / or STSA surface area described above are present.

[0058] Alternatively, when the starting material consists of more than 50% lignin, refined pCM is preferably obtained by precipitation and co-stabilization under hydrothermal carbonization (HTC) conditions. Such processes are known in principle to those skilled in the art and are described in International Publication No. 2016 / 020383 or International Publication No. 2017 / 085278 (Precipitation and Co-stabilization). Advantageously, these methods are controlled so that after the first process step, refined pCM is present characterized by the particle size distribution, BET surface area and / or STSA surface area described above.

[0059] Alternatively, finely milled pCM is preferably obtained by hydrolysis of a solid starting material, preferably wood or straw, in a first process step. In the process, the solid starting material is ground to the same extent as it would be present as finely milled pCM characterized by the particle size distribution, BET surface area, and / or STSA surface area described above, before and / or during hydrolysis and after the first process step. Since the carbohydrates contained in the starting material pass through the solution during hydrolysis, the finely milled pCM has an increased lignin content compared to the starting material. Such finely milled pCM obtained by hydrolysis advantageously has a lignin content of more than 60% by mass, preferably more than 65% by mass, and particularly preferably more than 70% by mass. Advantageously, these methods are controlled so that after the first process step, finely milled pCM is present, characterized by the particle size distribution, BET surface area, and / or STSA surface area described above.

[0060] A preferred embodiment of the second process step is described below. As mentioned above, the refined pCM obtained after the first process step can be converted to refined modified pCM according to the present invention by the second process step.

[0061] According to the present invention, pCM is converted to reformed pCM in a gaseous atmosphere in a second process step.

[0062] Advantageously, the second process step is carried out under a process atmosphere rather than in the open air. The process atmosphere is understood to mean, for example, the following: - Air rich in an inert gas having an oxygen content of less than 15 vol%, preferably less than 10 vol%, more preferably less than 5 vol%, and especially preferably less than 3 vol%; the absolute pressure of the air rich in an inert gas can be selected as needed, preferably up to 2000 mbar, more preferably up to 1500 mbar, preferably at least 100 mbar, more preferably at least 200 mbar, 250 mbar, 500 mbar, or 750 mbar. - Inert gas; the absolute pressure of the inert gas may be selected as needed, preferably up to 2000 mbar, more preferably up to 1500 mbar, preferably at least 100 mbar, and more preferably at least 200 mbar, 250 mbar, 500 mbar, or 750 mbar. - Reduced pressure air having a pressure of less than 750 mbar, preferably less than 500 mbar, more preferably less than 250 mbar, and in some cases less than 100 mbar.

[0063] Advantageously, the oxygen content of the process atmosphere, which consists of air rich in an inert gas, is at least 0.1 volume%, preferably at least 0.5 volume%, and particularly preferably at least 1 volume%.

[0064] Suitable inert gases in the sense of the present invention are, in particular, nitrogen, carbon dioxide, superheated steam, or gas released from the pCM during the second process step. Gases released from the pCM during the second process step also include, for example, carbon monoxide, hydrogen, methane, or hydrogen sulfide, but are referred to as inert gases in this document. When using air rich in inert gas, or when using an inert gas as the process atmosphere, the pressure may be selected according to the respective possibilities or requirements, as already shown above. The simplest method from an equipment standpoint is to run the process at atmospheric pressure, or simply at a slight negative or positive pressure, for example, ±50, preferably ±25 mbar, and particularly preferably ±10 mbar.

[0065] The second process step is preferably controlled (by, for example, the selection of temperature profile, maximum temperature, process atmosphere, and possibly pressure) so that the mass loss of pCM in the second process step is less than 20%, preferably less than 15%, more preferably 10%, 9%, 8%, 7%, 6%, 5%, less than 4%, and 3% or less. A certain mass loss is required during the second process step of the method according to the present invention to reduce the content of odorants and / or reduce, preferably adjust, the OH group density. This mass loss is usually at least 1%, preferably at least 2%, and in some cases 5% or more. This ensures that too much material is lost, while at the same time achieving the desired odor reduction and / or OH group density reduction. In this way, the suitability of modified pCM used as a filler in elastomers, for example, can also be ensured.

[0066] Regardless of the selection of the process atmosphere for the second process step, the process temperature for the second process step should be above the minimum temperature and not above the maximum temperature. The maximum temperature is 300°C, preferably 250°C or less, more preferably 240°C, particularly preferably 235°C or less, even more preferably 230°C or less, particularly preferably 225°C, 220°C in some preferred cases, even more preferably 210°C, and in rare cases even further below 200°C. The minimum temperature is 80°C, preferably 100°C, preferably 120°C, preferably 130°C or higher, even more preferably 150°C or higher, particularly preferably 160°C or higher, especially preferably 170°C or higher, and in some cases 180°C or higher. The residence time for which pCM is held in the process atmosphere at the process temperature in the second process step may be selected over a wide range. A suitable value is between 1 second and 5 hours. Preferably, the residence time is 60 minutes or less, more preferably 30 minutes or less, particularly preferably 15 minutes or less, and in some cases less than 10 minutes. With respect to the continuous operation of the second process step, the residence time should be understood as the average residence time.

[0067] Preferably, the OH group density of the refined pCM is adjusted during a second process step. Advantageously, this adjustment is achieved by selecting a process temperature, preferably in combination with a process atmosphere, and particularly preferably by adjusting the oxygen content of the process atmosphere.

[0068] For example, by combining a low process temperature, preferably below 250°C, more preferably below 240°C, particularly preferably below 235°C, even more preferably below 230°C, particularly preferably below 225°C, below 220°C in some preferred cases, even more preferably below 210°C, and even less than 200°C in rare cases, with the adjustment of the oxygen content, the OH group density can be adjusted as intended without exposing the material to high thermal stress. This preserves the micronization as much as possible, reduces odor as much as possible, and adjusts the OH group density.

[0069] It was found that it is advantageous not only for pCM to be processed under the process atmosphere during the residence time in the second process step, but also for heating and cooling to be carried out under the process atmosphere.

[0070] When pCM is obtained from softwood lignin in the first process step, for example by precipitation using combined stabilization under hydrothermal carbonization conditions, the mass loss is only 10% or less, and at a maximum processing temperature of 250°C or less, it is approximately 5 m 2 This can be achieved with simultaneous losses of a BET surface area of ​​less than / g (i.e., pCM is 40m) 2 If the BET surface area is / g, this is up to 35m 2 (equivalent to / g). Simultaneously, odor tests show a significant reduction in the generation of unpleasant odors. This reduction was observed not only for the odor-reducing pCM itself, but also for rubber products manufactured using odor-reducing pCM as a filler, in addition to the rubber products themselves, compared to other products using pCM that had not undergone the second process step.

[0071] The method according to the present invention can thus achieve a good balance between desirable odor minimization and / or reduction of OH group density, while simultaneously preserving the most desired material properties and minimizing mass loss. This does not require the use of process chemicals or complex procedures. Furthermore, the maximum temperature of the treatment according to the present invention is in a relatively low range, which is advantageous in terms of both cost and process control.

[0072] Preferably, the second process step is carried out in a moving bed, fluidized bed, or co-flow. More preferably, the second process step may be combined with liquid separation. Advantageously, the liquid separation is carried out by evaporation, at least in part. Advantageously, the evaporation of the liquid is carried out to a dry material content of >80%, preferably >85%, such that the atomized pCM reaches a temperature of at least 35°C, preferably at least 40°C, during evaporation.

[0073] Advantageously, the evaporation of the liquid is carried out to a dry material content of >80%, preferably >85%, such that the granulated pCM reaches a temperature of up to 130°C, preferably up to 125°C, more preferably up to 120°C, particularly preferably up to 115°C, even more preferably up to 95°C, and particularly preferably up to 90°C during evaporation. Advantageously, the granulated pCM is raised to the process temperature of the second process step only if it has a dry material content of more than 85%, more preferably more than 90%, and particularly preferably more than 95% by mass.

[0074] As already described above, modified pCM obtained according to the present invention, preferably based on lignin, preferably by precipitation or precipitation using stabilization combined under conditions such as hydrothermal carbonization, is also proposed for use in rubber mixtures.

[0075] In the context of the present invention, it has also been shown that modified pCM produced according to the present invention is also modified to be polar or hydrophobic and is suitable for use in elastomer compounds that are more hydrophobic or less polar than pCM produced according to the prior art. Preferably, the elastomer compound containing the modified pCM swells only in alkaline liquids, under certain conditions. Preferably, the mass increase of the elastomer compound containing the modified pCM after 7 days in the medium is less than 25%, preferably less than 15%, and more preferably less than 10%.

[0076] As mentioned above, the first subject of the present invention is the modified pCM provided by the method according to the present invention, namely, It is above 0.20 Bq / g carbon, but lower than 0.45 Bq / g carbon. 14 C content, D50 with a particle size distribution of less than 500 μm and greater than 0.5 μm. Having an OH group density of at least 0.05 mmol / g and a maximum of 0.4 mmol / g, This is a granular carbon material whose solubility in alkaline liquids is less than 25%.

[0077] Preferably, the granular carbon material according to the present invention is - Greater than 0.23 Bq / g carbon, but preferably lower than 0.45 Bq / g carbon. 14 Having a C content, and / or - Having a carbon content between 60% and 80% by mass relative to the dry material without ash, and / or - There is no measurable glass transition temperature according to DIN 53765-1994, and / or - Having a volatile component content of more than 30% by mass as measured at 950°C according to DIN 53552, and / or - It has a volatile component content of less than 5% by mass, as measured at 200°C according to DIN 53552.

[0078] Advantageously, the BET surface area of ​​the modified pCM is at least 5m². 2 / g, at least 8m 2 / g, more preferably at least 10m 2 / g, more preferably at least 15m 2 / g, particularly preferably at least 20m 2 / g, more preferably at least 30m 2 / g, especially at least 35m 2 It is 1 / g or more. Advantageously, the BET surface area of ​​the modified pCM is a maximum of 200m². 2 / g, preferably up to 180m 2 / g, more preferably up to 150m 2 / g, particularly preferably up to 120m 2 It is / g.

[0079] Advantageously, the BET surface area of ​​the modified pCM differs from its STSA surface area by at most 20%, preferably at most 15%, and more preferably at most 10%. Therefore, the modified pCM preferably has a low porosity.

[0080] The D50 particle size distribution of the modified pCM is less than 500 μm, preferably less than 250 μm, more preferably less than 100 μm, and most preferably less than 50 μm. Advantageously, the D50 particle size distribution of the modified pCM is greater than 0.5 μm, preferably greater than 1 μm, most preferably greater than 5 μm, and even more preferably greater than 10 μm. Particularly preferable, the D50 particle size distribution of the modified pCM is greater than 5 μm, and even more preferably greater than 10 μm.

[0081] Advantageously, the modified pCM has an ash content of less than 15% by mass, preferably less than 12% by mass, 10% by mass, 8% by mass, 6% by mass, 5% by mass, 4% by mass, 3% by mass, or 2% by mass or less. Advantageously, the ash content of the modified pCM is greater than 0.25% by mass, preferably greater than 0.5% by mass, and more preferably greater than 0.75% by mass. Particularly preferable, the modified pCM has an ash content of 4% by mass, less than 3% by mass, 2% by mass or less, and greater than 0.25% by mass, preferably greater than 0.5% by mass, and more preferably greater than 0.75% by mass.

[0082] Furthermore, the modified pCM exhibits an OH group density of at least 0.05 mmol / g, preferably at least 0.075 mmol / g, and particularly preferably at least 0.1 mmol / g. The modified pCM exhibits an OH group density of up to 0.4 mmol / g, preferably up to 0.35 mmol / g, particularly preferably up to 0.3 mmol / g, and in some cases less than 0.25 mmol / g, and in rare cases less than 0.2 mmol / g.

[0083] Modified pCM is conditionally soluble only in alkaline liquids. The solubility of modified pCM is less than 25%, preferably less than 15%, and particularly preferably less than 10%. The soluble percentage is determined according to the method described below. Preferably, the alkaline liquid represents an aqueous solution of NaOH, particularly preferably an aqueous solution with a concentration of 0.1 mol / l.

[0084] Modified pCM preferably has reduced odor. Therefore, the emission rate of phenolic substances, particularly sulfur, is reduced. However, the emission of some VOCs, such as acetic acid, can also be reduced. One method for measuring the amount of emission is described below.

[0085] Preferably, the modified pCM contains dimethyl sulfide in a proportion of up to 1 mg / kg, preferably up to 0.5 mg / kg, more preferably less than 0.1 mg / kg, even more preferably less than 0.05 mg / kg, and especially less than 0.01 mg / kg.

[0086] Preferably, the modified pCM contains guaiacol and methylguaiacol (creosol) in amounts of guaiacol and methylguaiacol (creosol), respectively, at a maximum of 1 mg / kg, preferably at a maximum of 0.5 mg / kg, more preferably less than 0.1 mg / kg, even more preferably less than 0.05 mg / kg, and particularly less than 0.01 mg / kg.

[0087] Preferably, the modified pCM has a naphthalene content of less than 5 mg / kg (DIN EN 16181:2017-11 / draft). Preferably, the total of the 18 EPA-PAHs (DIN EN 16181:2017-11 / draft) that do not contain BG is less than 5 mg / kg. Preferably, the content of benzo[a]anthracene, chrysene, benzo[b]fluorantene, benzo[k]fluorantene, benzo[a]pyrene, indenol[1,2,3-cd]pyrene, dibenzo[a,h]anthracene, benzo[ghi]perylene, benzo(e)pyrene, and benzo[j]fluorantene is undetectable in the modified pCM (<0.1 mg / kg) (DIN EN 16181:2017-11 / draft).

[0088] Preferably, the modified pCM is determined by thermal desorption analysis according to VDA 278 (05 / 2016) to identify the individual degassable components. - 2-methoxyphenol - Phenolic acid - Guaiacol - 4-Methoxy-3-methylphenol - 4-Propanolguaiacol - 2-Methoxy-4-methylphenol - 2-Methoxy-4-ethylphenol - 4-Propylguaiacol - Methanol, The modified pCM content is less than 50 μg / g, preferably 25 μg / g, particularly preferably less than 15 μg / g, even more preferably less than 10 μg / g, particularly preferably less than 5 μg / g, and in some cases less than 1 μg / g.

[0089] Preferably, the OAN of the modified pCM is greater than 150 ml / 100g, more preferably greater than 151 ml / 100g, and particularly greater than 151 ml / 100g.

[0090] Preferably, the OAN of the modified pCM is less than 200 ml / 100 g, particularly preferably less than 180 ml / 100 g, and especially less than 170 ml / 100 g.

[0091] Preferably, the electrical resistance of an SBR polymer mixture crosslinked with sulfur and filled with 120 phr modified pCM is greater than 1.0E10 Ohm·cm.

[0092] Preferably, the modified pCM can be obtained by a method comprising at least two process steps, wherein a granular carbon material pCM corresponding to and different from the precursor of the granular carbon material according to the present invention is prepared in the first process step, which is then modified in the second process step by heating under a gas atmosphere, thereby obtaining the granular carbon material according to the present invention, which is preferably odor-reduced.

[0093] Preferably, the granular carbon material pCM that can be obtained according to the first process step had a D50 with a particle size distribution of less than 500 μm and greater than 0.5 μm before heating in a gas atmosphere.

[0094] Preferably, the OH group density of the granular carbon material pCM used is reduced or adjusted by heating in a gas atmosphere according to a second process step, thereby obtaining a modified pCM having the OH group density as defined above.

[0095] Preferably, the second process step is not carried out under atmospheric conditions, but under a process atmosphere consisting of air rich in an inert gas having an oxygen content of less than 15 vol%, preferably less than 10 vol%, more preferably less than 5 vol%, and most preferably less than 3 vol%, where the oxygen content is preferably at least 0.1 vol%, particularly preferably at least 0.5 vol%, and especially preferably at least 1 vol%.

[0096] Preferably, the granular carbon material pCM prepared in the first process step is obtained by precipitation of a starting material, preferably a lignin-based starting material, which is dissolved in whole or in part in a liquid.

[0097] Preferably, the process temperature of the second process step is at most 50°C lower and at most 50°C higher than the temperature of subsequent processing and / or use, and the process temperature does not exceed the maximum temperature and does not fall below the minimum temperature.

[0098] Preferably, the D50 particle size distribution of the modified granular carbon material that can be obtained after the second process step is greater than the D50 particle size distribution of the granular carbon material pCM prepared in the first process step by up to 5 times, preferably up to 4 times, 3 times, 2.5 times, 2 times, 1.75 times, 1.5 times, 1.4 times, 1.3 times, 1.2 times, or 1.1 times.

[0099] Another subject of the present invention is a method for producing granular carbon material according to the present invention, comprising at least two process steps, wherein a different granular carbon material pCM is prepared, which corresponds to a precursor of the granular carbon material according to the present invention, and which is subsequently modified in a second process step by heating under a gaseous atmosphere, thereby obtaining the granular carbon material according to the present invention, which is preferably odor-reduced.

[0100] Another subject of the present invention is the use of the granular carbon material according to the present invention as an additive in polymer mixtures, particularly rubber mixtures such as elastomer mixtures.

[0101] Another subject of the present invention is a vulcanizable rubber composition comprising at least one type of rubber and at least one filler component comprising at least granular carbon material according to the present invention.

[0102] The rubber composition may further include at least one vulcanization system comprising at least one crosslinking agent. Examples of such crosslinking agents are sulfur and / or peroxides. Examples of usable rubbers are natural rubber (NR) and halobutyl rubber, second most preferably chlorobutyl rubber (CIIR; chloroisobutene-isoprene rubber) and bromobutyl rubber (BIIR; bromoisobutene-isoprene rubber), butyl rubber or isobutylene-isoprene rubber (HR; isobutene-isoprene rubber), styrene-butadiene rubber (SBR), second most preferably SSBR (solution-polymerized SBR) and / or ESBR (emulsion-polymerized SBR), polybutadiene (BR, butadiene rubber), acrylonitrile-butadiene rubber (NBR, nitrile rubber) and / or HNBR (hydrated NBR), chloroprene (CR), polyisoprene (IR), ethylene-propylene-diene rubber (EPDM), and mixtures thereof, selected from the group.

[0103] Another subject of the present invention is a vulcanizable rubber composition that can be obtained by vulcanization and has a swelling of less than 25% after 7 days in an alkaline liquid. The swelling is determined in 0.1 mol of NaOH according to DIN ISO 1817:2015.

[0104] Measurement method 1. 14 Measurement of C content 14 The measurement of the carbon content (biologically based carbon content) is performed by the radiocarbon method in accordance with DIN EN 16640:2017-08.

[0105] 2. Measurement of particle size distribution The particle size distribution can be determined by laser diffraction of a material dispersed in water (1% by mass in water) according to ISO 13320:2009. The volume fraction is defined, for example, as D50 in μm (the diameter of particles representing 50% of the sample volume is less than this value).

[0106] 3. Measurement of carbon content The carbon content is determined by elemental analysis according to DIN 51732: 2014-7.

[0107] 4. Measurement of dry substance content The dry substance content of the samples was determined as follows, in accordance with the guidelines of DIN 51718:2002-06. For this purpose, the samples were heated to a drying temperature of 105°C using a Sartorius MA100 moisture balance. If the dry sample was not already in powder form, it was ground into a powder using a mortar and pestle or by grinding. Approximately 2 g of the sample to be measured was weighed into a suitable aluminum pan on the moisture balance, and then the measurement was started. As soon as the mass of the sample did not change by more than 1 mg in 30 seconds, the mass was considered constant, and the measurement was terminated. The dry substance content then corresponds to the stated content in percent of the sample mass. At least one duplicate measurement was performed for each sample. A weighted average value was reported.

[0108] 5. Measurement of Ash Content The water-free ash content of the samples was determined by thermogravimetric analysis according to DIN 51719 standard, as follows: Before weighing, the samples were crushed or mortared. Before ash measurement, the dry material content in the weighed material was determined. The sample material was weighed to the nearest 0.1 mg in a crucible. The furnace containing the samples was heated to a target temperature of 815°C at a heating rate of 9°K / min, and then held at this temperature for 2 hours. The furnace was then cooled to 300°C, after which the samples were removed. The samples were cooled to room temperature in a desiccator and weighed again. The remaining ash was related to the initial mass, and thus the mass percentage of ash was determined. Three measurements were performed for each sample, and the average value was reported.

[0109] 6. Measurement of BET and STSA surface area of ​​organic fillers The specific surface area was determined by nitrogen adsorption according to the ASTM D 6556 (2019-01-01) standard provided for industrial carbon black. According to this standard, the BET surface area (total specific surface area according to Brunauer, Emmett, and Teller) and external surface area (STSA surface area; Statistical Thickness Surface Area) were determined as follows:

[0110] The samples to be analyzed were dried at 105°C to a dry material content >97.5% by mass before measurement. Furthermore, the measuring cell was dried in a drying oven at 105°C for several hours before weighing the sample. The sample was then filled into the measuring cell using a funnel. If contamination was present on the top of the measuring cell shaft during filling, it was cleaned using a suitable brush or pipe cleaner. If (statically charged) material was released, glass wool was further weighed into the sample. The glass wool was used to contain material that could be released during the firing process and contaminate the equipment.

[0111] The samples to be analyzed were calcined at 150°C for 2 hours, and the Al2O3 standard was calcined at 350°C for 1 hour. The following N2 doses were used for the measurements, depending on the pressure range: p / p0 = 0 - 0.01:N2 dose: 5ml / g p / p0 = 0.01 - 0.5:N2 dose: 4ml / g.

[0112] To determine BET, extrapolation was performed in the range of p / p0 = 0.05 to 0.3, including at least 6 measurement points. To determine STSA, extrapolation was performed in the range of adsorbed N2 layer thickness from t = 0.4 to 0.63 nm (corresponding to p / p0 = 0.2 to 0.5), including at least 7 measurement points.

[0113] 7. Measurement of solubility in alkaline media The measurement of alkaline solubility is performed according to the following method: 1. To determine the solubility of a solid sample, it must exist in the form of a dry, fine powder (dry substance content > 98%). Otherwise, the dry sample must be pulverized or thoroughly ground in a mortar before determining its solubility. 2. Solubility is determined by repeating the process three times. For this purpose, 2.0 g of each dry sample is weighed into 20 g of 0.1 M NaOH. However, if the pH value of the sample is <10, the sample is discarded, and instead, 2.0 g of the dry packing material is weighed into 20 g of 0.2 M NaOH. In other words, depending on the pH value (<10 or >10), 0.1 M NaOH is used (pH > 10) or 0.2 M NaOH (pH < 10). 3. The alkaline suspension is shaken at a shaker speed of 200 bpm at room temperature for 2 hours. If the liquid comes into contact with the lid during the process, the shaker speed must be reduced to prevent this from happening. 4. Next, the alkaline suspension is centrifuged at 6000 xg. 5. The supernatant from the centrifugation is filtered using a Por 4 frit filter. 6. The solid after centrifugation is washed twice with distilled water by repeating steps 4 through 6. 7. The solid is dried in a dehydrator at 105°C for at least 24 hours until its mass is constant. 8. Alkali solubility is calculated as follows: Alkaline solubility of the sample [%] = Mass of the undissolved portion after centrifugation, filtration, and drying [g × 100 / Mass of the dried product obtained in item 2 [g]

[0114] 8. Measurement of pH value As described below, pH was determined in accordance with the guidelines of ASTM D 1512 standard. If the dried sample was not already in powder form, it was ground into a powder using a mortar and pestle or by grinding. In each case, 5 g of the sample and 50 g of completely deionized water were weighed into a glass beaker. The suspension was heated to a temperature of 60°C with constant stirring using a magnetic stirrer equipped with a heating function and a stirring bar, and the temperature was maintained at 60°C for 30 minutes. Subsequently, the heating function of the stirrer was stopped to allow the mixture to cool during stirring. After cooling, the evaporated water was replenished by adding completely deionized water again, and the mixture was stirred again for 5 minutes. The pH value of the suspension was determined using a calibrated measuring instrument. The temperature of the suspension should be 23°C (±0.5°C). A duplicate measurement was performed for each sample, and the average value was reported.

[0115] 9. Measurement of glass transition temperature The glass transition temperature is measured according to DIN 53765-1994.

[0116] 10. Measurement of emissions The content of degassable organic compounds (emissions) is determined by thermal desorption analysis according to VDA 278 (05 / 2016). The total degassable organic exhaust gas is given as the sum of measurements from VOCs and FOG cycles. The concentrations of individual components are determined by assigning signal peaks based on mass spectra and retention indices.

[0117] 11. Measurement of OH group density The measurement of available acidic hydroxyl groups (OH group density) on surfaces containing phenolic OH groups and phenolate groups was performed qualitatively and quantitatively by colorimetric measurements according to Sipponen. Sipponen's method, based on the adsorption of the alkaline dye azur B onto the acidic hydroxyl groups available on the filler surface, is described in detail in the paper "Determination of surface-accessible acidic hydroxyls and surface area of ​​lignin by cation dye adsorption" (Bioresource Technology 169 (2014), pp. 80-87). The amount of available acidic hydroxyl groups on the surface is given in mmol / g (filler).

[0118] The present invention will be described in more detail with reference to the embodiments illustrated herein, but should not be construed as limiting. [Examples]

[0119] In the first step, finely granular carbon material was produced from lignin by hydrothermal treatment in water.

[0120] The material used in the first step was lignin UPM BioPiva 190 (commercially available). The material used had a solubility of 68.5% in 0.1M NaOH.

[0121] Lignin was mixed with water while stirring, thus diluting it to an 11% dry material content (DM content). Next, 7.5 g of sodium hydroxide was added per 100 g of dry material. The mixture was heated to 80°C while stirring, and after 1 hour, a lignin solution with a pH of 10.1 was obtained.

[0122] Next, the lignin solution was heated to 220°C and subjected to hot water treatment at 220°C for 480 minutes. Subsequently, the resulting suspension was cooled to room temperature.

[0123] This resulted in a pH of 8.8.

[0124] The suspension sample was centrifuged at 12,000 rpm, and the resulting residue was dried. The dried residue was analyzed for BET and STSA. 39.4 m 2 BET of / g and 37.2m 2 STSA levels were measured at multiple points in g.

[0125] Next, the resulting lignin suspension was dehydrated and pressed using a filter press to mechanically dehydrate it to a DM content of 39.4%. In this way, a filter cake was obtained.

[0126] The D50 particle size distribution of the sample of suspended solid material in the filter cake was 5 μm.

[0127] The filter cake sample was dried. The dried filter cake was analyzed for BET and STSA. 38.3m 2 BET of / g and 36.1m 2 STSA levels were measured at multiple points in g.

[0128] The resulting filter cake represents granular carbon material pCM that has been refined and further processed (modified) in the second step.

[0129] In the second step, the finely modified granular carbon material (as per the present invention) was recovered from the finely modified granular carbon material pCM by heating in a gas atmosphere.

[0130] Samples were taken from the finely granular carbon material pCM obtained after the first step and treated under different conditions in the second step (Samples 1-5), or they were not treated in the second step but were only dried in air (Reference Sample REF).

[0131] Each sample was individually fed into a rotary fire-tube furnace that was continuously purged with nitrogen. The samples were first dried at 80°C, then heated to the process temperatures shown in Table 1 below, held for the indicated time, and set to the indicated gas composition. The samples were then cooled again to room temperature.

[0132] [Table 1]

[0133] Next, the obtained finely granular carbon materials were analyzed. The parameters given in Table 2 below were measured:

[0134] [Table 2]

[0135] Samples 1-5 and reference REF were mixed into an EPDM matrix as fillers. After vulcanization, the test specimens were swollen in aqueous NaOH (0.1M). The swelling after 7 days is shown in Table 3 below. Swelling was determined according to DIN ISO 1817:2015:

[0136] [Table 3]

[0137] The lower the solubility of each sample in 0.1% NaOH (see Table 2), the lower the swelling of the vulcanized product containing each sample as a filler in aqueous NaOH.

[0138] The compound mixture and vulcanized product were prepared according to the formulation in Table 4 and by the following process:

[0139] [Table 4]

[0140] The mixture was prepared according to the following method: The mixture was prepared using a W & P Type GK1,5E mixer (with interlocking rotor geometry) at a filling ratio of 70%, a mixing temperature of 40°C, and a mixing speed of 40 rpm.

[0141] Vulcanization was performed by firing at 160°C according to the optimal t90 time determined using a rheometer.

Claims

1. A granular carbon material, More than 0.20 Bq / g carbon but less than 0.45 Bq / g carbon １４ C content rate, A particle size distribution D50 of less than 500 μm and greater than 0.5 μm, and an OH group density of at least 0.05 mmol / g and at most 0.4 mmol / g; 1. A granular carbon material having: the solubility of the granular carbon material in the alkaline liquid is less than 25%; The alkaline liquid is an aqueous solution of 0.1M or 0.2M NaOH. A granular carbon material characterized by:

2. 2. Granular carbon material according to claim 1, characterized in that it has an ash content of less than 15% by weight and more than 0.25% by weight.

3. 3. Granular carbonaceous material according to claim 1 or 2, characterized in that it has an ash content of less than 4% by weight and more than 0.5% by weight.

4. 4. A granular carbon material according to any one of claims 1 to 3, characterized in that it has a particle size distribution D50 of less than 250 μm and greater than 1 μm.

5. 5. A granular carbon material according to any one of claims 1 to 4, characterized in that it has a particle size distribution D50 of greater than 5 μm.

6. 6. A granular carbonaceous material according to any one of claims 1 to 5, characterized in that its solubility in alkaline liquids is less than 15%.

7. The granular carbon material according to claim 1, wherein the solubility is determined as follows:

1. To determine the solubility of a solid sample, it must be in the form of a dry, fine powder with a dry matter content >98%. Otherwise, the dry sample must be ground or thoroughly mortared before determining the solubility.

2. Solubility is determined in triplicate. For this purpose, 2.0 g of each dry sample is weighed into 20 g of 0.1 M NaOH, respectively. However, if the determined pH value of the sample is <10, the sample is discarded and 2.0 g of dry filler is instead weighed into 20 g of 0.2 M NaOH. In other words, depending on whether the pH value is <10 or >10, 0.1 M NaOH is used when the pH is >10, and 0.2 M NaOH is used when the pH is <10.

3. The alkaline suspension is shaken at room temperature for 2 hours at a shaker speed of 200 per minute. If the liquid comes into contact with the lid during the process, the shaker speed must be reduced to prevent this from happening.

4. The alkaline suspension is then centrifuged at 6000 x g.

5. The centrifugation supernatant is filtered through a Por 4 frit.

6. After centrifugation, the solid is washed twice with distilled water by repeating steps 4 to 6.

7. The solid is oven dried at 105°C for at least 24 hours to a constant weight.

8. Alkali solubility is calculated as follows: Alkali solubility of sample [%] = mass [g] of insoluble fraction after centrifugation, filtration and drying × 100 / mass [g] of dried product obtained in item 2.

8. 8. A granular carbon material according to any one of claims 1 to 7, characterized in that it has an OH group density of at least 0.075 mmol / g and at most 0.35 mmol / g.

9. More than 0.23 Bq / g carbon but less than 0.45 Bq / g carbon １４ and / or no measurable glass transition temperature according to DIN 53765-1994, and / or having a carbon content of between 60% and 80% by weight based on ash-free dry matter, and / or have a content of volatile components of more than 30% by weight, measured at 950°C according to DIN 53552, and / or has a content of volatile constituents of less than 5% by weight, measured at 200°C according to DIN 53552 9. The granular carbon material according to claim 1, wherein the granular carbon material is a granular carbon material.

10. At least 5m ２ 10. A granular carbon material according to any one of claims 1 to 9, characterized in that it has a BET surface area of ​​200 m2 / g and at most 200 m2 / g.

11. 11. Granular carbonaceous material according to any one of claims 1 to 10, characterized in that the contents of dimethyl sulfide, guaiacol and methylguaiacol (creosol) are each less than 1 mg / kg.

12. A method for producing a granular carbon material as defined in any one of claims 1 to 11, comprising at least two process steps, in a first process step a granular carbon material pCM corresponding to but different from a precursor of the granular carbon material as defined in any one of claims 1 to 11 is prepared, which is subsequently modified in a second process step by heating under a gas atmosphere, thereby obtaining the granular carbon material as defined in any one of claims 1 to 11.

13. 13. The method according to claim 12, characterized in that, before heating in a gas atmosphere, the granular carbon material obtainable according to the first process step had a particle size distribution D50 of less than 500 μm and greater than 0.5 μm.

14. 14. A method according to claim 12 or 13, characterized in that the OH group density of the granular carbon material pCM used is reduced or adjusted by heating in a gas atmosphere in a second process step, thereby obtaining a granular carbon material according to any one of claims 1 to 11 having an OH group density as defined in claim 1 or 8.

15. 15. The method according to any one of claims 12 to 14, characterized in that the second process step is carried out not under atmospheric pressure but under a process atmosphere consisting of air enriched with an inert gas having an oxygen content of less than 15% by volume and at least 0.1% by volume.

16. 16. A method according to any one of claims 12 to 15, characterized in that the granular carbon material pCM provided in the first process step is obtained by precipitation of starting materials dissolved in whole or in part in a liquid.

17. 17. The method according to any one of claims 12 to 16, characterized in that the process temperature of the second process step is at most 50°C lower and at most 50°C higher than the temperature of further processing and / or use, such that the process temperature does not exceed the maximum temperature and does not drop below the minimum temperature.

18. 18. The method according to any one of claims 12 to 17, characterized in that the D50 of the particle size distribution of the modified granular carbon material obtainable after the second process step is up to 5 times larger than the D50 of the particle size distribution of the granular carbon material pCM provided in the first process step.

19. Use of a granular carbon material according to any one of claims 1 to 11 as an additive in polymer mixtures, including rubber mixtures.

20. 12. A vulcanizable rubber composition comprising at least one rubber and at least one filler component, wherein the filler component comprises at least the particulate carbon material of any one of claims 1 to 11.

21. 21. A vulcanized rubber composition obtainable by vulcanization of the vulcanizable rubber composition according to claim 20, characterized in that it exhibits a swelling of less than 25% in an alkaline liquid after 7 days.