DE1151894B - Process for the preparation of binary mixtures of carbon black and a dispersing agent - Google Patents

Description

Process # for production, -binätet mixed weight! Carbon black and a dispersant The invention relates to a process between conti, natural production of binary mixtures with pre- Herbestünrater composition, the previous, later Processing-. to printing inks, paints, and in , Kauti5 # chukmarkeeit intended; # sirrd # - This Mixtures - consist - - - of - - a solid phase # due to incomplete '.Vdrhrnung''ein: es - Kohl-eii # soot particles containing hydrogen and a continuous. Phase aifg # - zeineni non-aqueous, niece » volatile, liquidr or iii'der, heat easily- Vera: liquidable substance, namely-> äinem - Bihdeniittel for. Ailstrioh inks, printing inks or -a 'soft4 inncher, for Kgutschuk-. These substances should, besides in -, # liquid state: * fill in the soot particles - to # can cover.- -. #, --le; 'z ; - - -. # The coal soot, which by incomplete text: bfnung or by 'Zeisetzuhg of liquid or wasted gaseous hydrocarbons in facilities ver # chiedendr, -Art, eräalten. * w.er'de "n- able, possessed numerous industrial uses. :; One uses- # gie-ingbesöftdeie Ms-Füllgtöff # 'odet Pigments in production; vöyf printing ink, Colors, - objects # laüs - rubber- t or - plastic- .. Materials, - r, '-: - 1 d gl. - 1-. * -. - -. . . Regardless of the type of production, d6t forms Carbon black extremely fine & particle (with Durblünessern between 50 and 5000 ailgström). This-distribution # degree gives the Cologne soot its main look Properties, but also has heavy ones Disadvantages result, such as # e.g. - e.g. the formation of a very pervasive, and filthy dust, a very large volume as a result of the mentioned Di , ch-te, 'what, difficulties with the -hand .: conditionally, the tendency for the particles to agglomerate under certain. ' ! Feuc'hti'gkeits-, or eleI # tri- see conditions, great difficulty converting the soot into a liquid or to disperse viscous phases, since the. did .notential total tob. surface, of the soot particles not easily wetted. can be. It is formed -therefore agglomerates, their destruction. note7- Liche mechanical forces required. The invention eliminates those enumerated above Disadvantages by now using simple mechanical niche means and with little energy expenditure a soot dispersion is obtained in which the soot particles are available individually; the binary mixtures obtained facilitate the subsequent-; Processing and heights under otherwise the same as-the usual conditions - the quality: of the desired; - breed products; namely the printer colors - # of paints and Kautschuknüschungen.

We already know various methods of practice;. For the dispersion of- Pigments in a liquid phase with the achievement of a paste-like mixture.

# Such methods - however, concern pigments other than carbon black and - because of the special # properties of carbon black - cannot be applied to them; it is especially its extreme delicacy and its tendency to agglomerate. - # '- In this Verfahren- eini-en used to Wassei as Dispe # sionsiffitteli water, however, is for: -vorliegendö # Erfindüng ausgeschlosseii not da.eg in -the erfindungsgemäß- erhaltenen- end products (printer inks, oil paints, rubber compounds) finds ..,: - The use-of a wetting agent # to facilitate the -.Use, - such dispersion not- - & of pigments, in the context - is known. Substances entering the desired end product are likewise excluded according to the invention; the only condition that is placed on the continuous dispersion phase is that this phase must envelop each individual soot particle. - Also is the manufacture of. Pearls or cookies based on carbon black are known to the. To reduce dust formation that occurs when using carbon black. If these pearls are obtained by dry processes, they can only be dispersed poorly in a liquid phase and form agglomerates. The same applies if the production of such pearls or biscuits is carried out by binding the carbon black with an oil . To overcome this disadvantage, it has been proposed to disperse the carbon black in a mixture of oil, water and a surface-active agent. However, substances must be added to the soot, which then again, z. B. must be separated by heating. Such substances can also change the properties of the carbon black and make its subsequent use in compositions incompatible with a wetting agent impossible. Moreover, because of the preceding agglomeration and in view of the extremely difficult production of carbon black dispersions, subsequent redispersion is only possible with difficulty, since the agglomerates cannot be comminuted again into microscopically fine particles. Processes are also known in which the carbon black particles are mechanically ground in a suitable amount of binder.

However, these grinding methods require a very heavy material and consume a lot of power. The method according to the invention enables the introduction of soot into the desired end products without any intermediate crushing.

Incidentally, grinding a mixture of soot particles and a liquid binder does not result in a dispersion of elementary soot particles, but only of larger particle groups, since soot particles with a diameter of 0.7 microns still, for example, more than 10,000 soot particles with a diameter of 25 Millimicrons included.

One must bear in mind that the quality of the mixture obtained as the end product (the intensity of the color for a paint or printing ink, the abrasion resistance for a rubber mixture), the greater the smaller the dispersed carbon black particles. are.

In some cases it has been suggested to use the liquid phase volatile substance, e.g. B. benzene, add to facilitate dispersion. the However, experience has shown that the evaporation of this substance reduces the quality of the Dispersion is adversely affected by this additional process step Can form agglomerates.

The dispersants used according to the invention are non-volatile.

There have also been processes for the continuous production of binary Proposed mixtures that can be used as printing inks and from a direct Consists of dispersion of soot in a non-volatile liquid.

In this process, the soot particles are immediately after their Formation dispersed in an excess of liquid and then by centrifugation separated again; the liquid recovered in this way can then be circulated will.

However, these processes, the concept of which is already old, cannot be applied on an industrial scale. Namely, in these processes, the soot is obtained by decomposing a hydrocarbon by means of an electric arc generated within this hydrocarbon. Taking into account the temperature of the electric arc (about 1500 C), so a partial cracking of the hydrocarbon is inevitable d. That is, the formed carbon black is dispersed in an already decomposed medium, which makes it impossible to use the dispersion obtained for applications in which the continuous phase is to have a certain quality.

A major disadvantage in the production of carbon black by means of the electric arc is that the particles obtained are different are, since the conditions prevailing when they arise differ from one place to the other of the electric arc as well as with time according to the Change the decomposition of the liquid.

Now, however, those are in the technology of the properties The conditions imposed by soot are extremely numerous and precisely defined (at least nine conditions must be met each), and the respective properties of the carbon black narrowly limit its use. When these properties are indefinite, such a product cannot find technical use nowadays.

In contrast to the procedure of the citations one uses according to the invention, a carbon black with precisely defined and constant values as the starting material Properties that are based on a currently recognized and technically proven process will be produced. These soot particles obtained in a known manner are then used in accordance with the invention in a liquid phase with also precisely defined and unchanging Properties dispersed, the conditions being chosen during the dispersing that the properties of both carbon black as. also of dispersion medium, no can be changed and that above all none during the dispersion Agglomeration of the soot particles can occur.

The method according to the invention for the continuous dispersion of soot in a coherent phase is characterized in principle by the fact that the soot particles produced in conventional soot furnaces, enveloped in the combustion gases, are cooled and, without intermediate storage of these gases, are taken from the soot production facility and introduced in parallel into several dispersion stages , which contain mechanical centrifugal dispersants and are continuously flowed through by the liquid dispersion medium one after the other, this progressively accumulating in soot and wherein the liquid throughput in each stage in relation to the soot throughput, based on the weight, is clearly greater and to avoid agglomerate formation Ratio between 25 and 100 parts of liquid to 1 part of carbon black, whereupon the binary mixture formed by mechanical separation of the excess liquid, e.g. B. by centrifugation, squeezing, but not enriched in soot by drying and the separated liquid is returned to the cycle.

Experience has surprisingly shown that agglomerate formation of the soot particles in the dispersion stages is completely avoided if the soot is discharged from the soot furnace continuously and without intermediate storage in the presence of the combustion gases. On the basis of current knowledge, this can be explained by the fact that the properties of the carbon black do not only depend on its dimensions, but are also a function of the chemically bonded oxygen and hydrogen quantities. H. In other words, the properties depend on the volatile substances on the carbon black surface. In addition, the activity of the surface can also have an influence on the properties of the carbon black.

The new process ensures for the first time that the soot particles surrounding gas atmosphere remains unchanged until the soot particles as a result their dispersion in the liquid phase are withdrawn from the action of the gases. This peculiarity is the reason for the excellent results achieved.

The invention thus enables the preparation of a dispersion of a soot produced in a known, currently customary manner with very precise and constant Properties in a liquid with also constant, precisely defined properties, whereby the soot particles have not changed since the moment they were formed to have. The binary mixtures obtained therefore have exactly those intended for one Purpose of use desired properties.

However, also the other marked peculiarities of the method according to the invention are important.

The dispersion of the carbon black in a medium that completely removes the carbon black particles envelop and can still be contained in the end product is how in practice follows fulfilled: So one disperses z. B. carbon black to produce a printing ink in a petroleum oil, which is the usual binder for such printing inks. If the carbon black is to be incorporated into rubber mixtures, the desired one is used Plasticizers (e.g. stearic acid, pine tar, etc.). If the plasticizer consists of a mixture of several substances, one puts in each case separate dispersions each of the individual substances.

By doing this, any chemical reaction between the dispersion medium is eliminated and the end product avoided, and moreover, the binary mixture can be in a uniform liquid phase can be diluted very easily.

The parallel dispersion stages fed with the soot particles the dispersion liquid is fed one after the other, namely to the first stage the pure dispersant and the following the progressively accumulating in soot binary mix; the dispersion liquid is in a closed circuit guided.

Thanks to this arrangement you can if the circulation speed the liquid is high compared to the soot throughput, with a relatively low one absolute liquid volume a desired volumetric ratio of soot to get liquid.

One should consider the formation of agglomerates in one of the dispersion stages determine, this can easily be remedied by reducing the soot throughput or increases the liquid throughput.

The excess liquid provided according to the invention results from the invention. Condition that the carbon black is completely without the formation of agglomerates Must be dispersed, each individual soot particle from a liquid film is surrounded. The determination of the theoretical soot surface provides an indication for the approximate amount of fluid required.

Since the excess liquid mechanically with the exclusion of therinischer means, z. B a heat evaporation is removed, also the wrapping of the individual carbon black particles during the concentration of the dispersion can not be destroyed.

Experience has shown that when the individual soot particles brought into dispersion and thus removed from the action of the atmosphere, they are not more tend to agglomerate. You can then use the liquid phase very largely separate mechanically, which increases the volume of the soot to be stored is reduced without the risk of subsequent renewed dilution the dispersion is thereby disturbed. This enables a great improvement the color strength in the case of paints and inks and the mechanical resistance when used in rubber compounds.

The method according to the invention is particularly suitable for the current ones technical carbon black production process and allows the dispersion to be considerable Amounts of soot produced per unit of time.

The drawing shows a schematic representation of an inventive Device for continuous soot dispersion.

In the drawing, 21 denotes a conventional oven for manufacturing, a technical carbon black, specifically for the production of furnace black, sewer black and thermal Soot.

The furnace 21 is fed with air and hydrocarbons through the lines 22 and 23, respectively. The latter experience incomplete combustion in the furnace 21. The soot produced in the process is carried along by the combustion gases into a cooler 24, a separator 25 and cyclones 26.

The cooled soot particles then pass through a line 27 in parallel into several homogenizers 31, which are connected to one another in a cascade manner. The first homogenizer is fed with the dispersion liquid through a line 32.

The homogenizers are of a known type and contain coaxial, rotating organs moving in opposite directions around the same Rotate axis; the soot particles and the homogenizers are carried out at the same time the liquid, both of which enter along the axis of rotation. The soot particles are intimately dispersed in the liquid by centrifugal forces.

The type of dispersion liquid is determined, as already said, by the later use of the soot, as this liquid is part of the The end product.

So one uses z. B. as a binder for a dye vat a petroleum oil. Suitable plasticizers for rubber as dispersants for carbon black are pine tar, unsaturated aromatic hydrocarbons, stearic acid (liquefied by hot water) and esters, e.g. B. butyl phthalate.

In the example described, the dispersion medium is a plasticizer for rubber, e.g. B. a petroleum oil, which consists of a mixture of unsaturated hydrocarbons consists. The plasticizer is expediently heated in order to make it more fluid.

The Ho.-inogenisatoren31 give off the liquid phase, one to the other, with carbon black being added in each stage through the appropriately branched line 27.

The plasticizer thus gradually accumulates in soot. The addition of carbon black and plasticizer into the homogenizers 31 takes place continuously, as does the discharge of the binary mixture formed through the line 40.

The weight ratio of liquid to carbon black in each homogenization stage depends on the fineness of the carbon black and the coating capacity of the plasticizer. As already said, the ratio in the end is between 25 and 100.

The maximum obtainable soot concentration is in each case experimental determined within certain limits on the basis of the appearance of the first agglomerates.

In all cases the relative proportions are more prevalent Liquid to soot in such a way that the soot concentration of the liquid phase at the outlet from the dispersion stages is significantly less than it is in the end product it is asked for.

The facility is located opposite the atmosphere under überluck. In order to avoid the escape of soot particles (as a result of the dust formed by them), a completely tight connection must be provided between the soot production furnace 21 and the dispersion stages 31. Since the soot is accompanied by the combustion gases and the rotating elements of the homogenizers exert a suction effect, the soot particles are removed from the combustion gases until they enter the homogenizers. accompanied and enveloped by these, db, the use of the homogenizers ensures a particularly good compliance with the main condition of the method according to the invention.

The line 40 ends in a spinner 35, in which the mixture of carbon black and plasticizer is spun off. The plasticizer is then returned to the dispersing stages through line 36 (preferably by passing through a regeneration stage, not shown).

The remainder emerging from the centrifuge 35 consists of a paste which, for. B. contains 50 percent by weight plasticizer and 50 1 / o carbon black; this paste is sent through line 37 to automatic hydraulic presses 38 which squeeze out a further part of the plasticizer to obtain practically solid blocks.

The excess plasticizer is also fed back into the circuit through line 36. Example An hourly accumulation of 150 kg furnace soot (type HAF) is dispersed in a petroleum oil passing through the first homogenizer at a rate of 67501 per hour.

After the excess liquid has been spun off, a mixture of 150 kg of carbon black and 150 kg of petroleum oil is obtained. This mixture is concentrated even further in the press so that 150 kg of carbon black, dispersed in 75 kg of petroleum oil, is obtained per hour.

The use of the binary products obtained according to the invention in the carbon black processing industry is very simple and particularly adaptable. So you can z. B. to produce a printing ink containing 511 / o carbon black and 950.10 petroleum oil, it is advisable to dilute the paste emerging from the centrifuge 35 to the desired concentration. It is only important that the oil used for dilution is the same as that in which the carbon black was dispersed, or that it is compatible with it.

If the printing ink consists of a mixture of 2.511 / o furnace soot and 2.511 / o canal black with 9011 / o binder, a mixture of pastes is made in which once the sewer soot and once the furnace soot were dispersed. Since all. Soot particles in the pastes according to the invention are encased by the dispersant, is no further comminution for all subsequent mixing or dilution processes and no great expenditure of energy is required.

The same applies to the blocks emerging from the filter press 38. These blocks are particularly suitable for the production of black rubber for tires, shoe soles, straps, belts, etc. In this case the binary mixtures contain a very high proportion of carbon black, which can be 40 to 100 parts with 5 to 15 parts of plasticizer per 100 parts of rubber. So z. B. a composition used for the running track of tires have the following carbon black and plasticizer contents: 45 parts carbon black, 2 parts spruce tar, 3 parts stearic acid. To facilitate the processing of such mixtures, the invention also provides for the use of blocks with different compositions but with standard contents.

So in the above example you can get the desired composition obtained by adding a certain amount of a dispersed in spruce tar Carbon black and a block consisting of carbon black dispersed in stearic acid.

In general, the carbon black blocks are incorporated into the rubber in the production of mixtures according to common methods used in the rubber industry Methods and with the usual tools.

If the composition of the final mix calls for more plasticizer, than it is contained in the soot blocks, or another plasticizer is required the addition of an additional amount of plasticizer does not cause any trouble. In all cases that is necessary to achieve an agglomerate-free mixture Energy significantly reduced.

Claims (2)

PATENT CLAIMS: 1. Process for the continuous production of binary mixtures intended for the production of printing inks, paints and rubber mixtures with a predetermined composition, containing a solid phase consisting of soot particles obtained by incomplete combustion of a hydrocarbon and a phase consisting of a non-aqueous, non-volatile, liquid or A coherent phase that is easily liquefied by heat, namely a binding agent. for paints, printing inks or a plasticizer for rubber, which in the liquid state can individually envelop the soot particles. B. by centrifugation, partially separated again and returned to the cycle, characterized in that the soot particles produced in conventional soot furnaces, encased in the combustion gases, cooled and continuously and without intermediate storage of these gases from the soot production facility and in parallel in several Dispersion stages are introduced which contain mechanical centrifugal dispersants and are continuously flowed through by the liquid dispersion medium one after the other, this progressively enriching in soot and wherein the liquid throughput in each stage in relation to the soot throughput, based on the weight, is clearly greater and to avoid it agglomerate formation corresponds to an approximately 25 to 100-fold excess of liquid, whereupon in a manner known per se in the binary mixture formed by mechanical separation of the excess liquid, e.g. B. centrifugation, squeezing, but not by drying, the soot concentration is increased and the separated liquid is returned to the cycle. 2. The method according spoke 1, characterized in that homogenizers are used as mechanical centrifugal dispersants. Considered publications: German Patent Nos. 710 093, 716 238, 804 447; French Patent Nos. 803 516, 1070 663; U.S. Patent Nos. 1597 277, 1673 245; Deutsche FarbenZeitschrift, 1954, p. 358.