SK2522001A3 - Carbon black, method for producing carbon black and use of the same - Google Patents

Abstract

The inventive carbon black is characterised by an STSA surface of between 20 and 180 m<2>/g, a 24M4-DBP-absorption of between 40 and 140 ml/100g, a specific BET surface of between 20 and 250 m<2>/g, in that it contains 0.01 to 20 wt % silicon in relation to its total weight and in that it has a ratio of tan delta 0/tan delta 60 greater than 3.37-0.0068•STSA. The inventive carbon black is produced by adding silicon-containing compounds are added and mixed with the of carbon black raw material during the oxidative pyrolysis of the same and optionally, using carbon black oil as the fuel. The inventive carbon black can be used as a filler in rubber mixtures, preferably for tyres.

Description

Carbon black, process for their preparation and use

Technical field

The present invention relates to carbon black, to a process for the preparation of such carbon blacks and to their use, in particular as reinforcing carbon blacks in rubber compositions.

BACKGROUND OF THE INVENTION

Carbon blacks are known from Ullman's Encyclopedia Enzyklopädie der technischen Chemie, 4th ed. (1977) Vol. 14, p. 633 648.

The most important methods of preparing carbon black are based on the oxidative pyrolysis of carbon-containing carbon black feedstocks. The carbon black raw materials are incomplete combustion in the presence of oxygen at high temperatures. These methods of preparation include, for example, retort, gas or lamp black. Multicore aromatic soot oils are predominantly used as the feedstock on carbon black.

Carbon black is used as a filler and as a reinforcing agent in the preparation of rubber compounds in the tire industry. Typical rubber compositions contain carbon black, mineral oil and other excipients such as sulfur as a vulcanizing agent in addition to natural and / or synthetic rubber.

The carbon black affects the abrasion resistance, the rolling resistance as well as the slip behavior of the tires made of these rubber compounds. Rubber compositions which serve as a raceway surface, the so-called raceway surface mixtures, require high abrasion resistance while at the same time having low rolling resistance and good wet slip behavior.

Low rolling resistance leads to low fuel consumption of the vehicle.

The rolling resistance and wet slip properties are influenced by the viscoelastic behavior of the running surface mixture. During periodic deformation, the viscoelastic behavior can be described by the mechanical loss factor tand5 and in the case of expansion or contraction by the dynamic modulus of elasticity / E7. Both variables strongly depend on temperature.

The wet slip behavior of the mixture surface is correlated with a loss factor tand at 0 ^e C and a rolling resistance with a loss factor tan at 60 ° C. The higher the loss factor at low temperature, the better the tire compound typically has a wet slip behavior. On the other hand, a small loss factor at high temperature is required to reduce the rolling resistance.

Abrasion resistance and viscoelastic properties, thus also the loss factor of mixtures for running surfaces, are mainly determined by the properties of the reinforcing carbon blacks used.

An important characteristic of the rubber-active fraction of the carbon black surface is the specific surface, in particular the CTAB surface and the STSA surface, respectively. As the CTAB surface area and the STSA surface area increase, the rolling resistance and the tan.

Another important parameter of the carbon black is DBP-absorption as a measure of the initial structure and 24M DB DBP-absorption as a measure according to the mechanical requirement of the carbon black still remaining.

Carbon blacks having a CTAB surface area of between 80 and 180 rrfrg and a 24M4-DBP absorption value of between 80 and 140 ml / 100g are suitable for mixtures of impurities.

It is known that ASTM carbon black cannot influence the temperature dependence of the loss factor so that the runway mixtures exhibit less rolling resistance with the same or better wet slip behavior. The desired reduction in rolling resistance is directly associated with a deterioration of the wet slip behavior in a known manner. Carbon blacks that exhibit low rolling resistance are referred to as so-called "low hysteresis, carbon blacks."

It is further known that the rolling resistance of tires can be reduced by substituting soot for silicic acid (EP 0 447 066 A1). Coupling silane reagents are used to bind the silicic acid to the building blocks of the rubber polymers. Rubber mixtures containing silica have a loss factor tan £ _<a reduced by 50%.

It is an object of the present invention to provide carbon blacks that lend rubber compounds of rubber or natural rubber or mixtures thereof with reduced rolling resistance while improving or equal wet slip behavior and abrasion resistance.

SUMMARY OF THE INVENTION

The present invention relates to carbon black having a STSA surface of between 20 and 180 µg, a 24M4-DBP absorption of between 40 and 140 ml / 100g, a BET surface area of between 20 and 250 µg and a silicon content of 0.01 to 20% by weight. to their total weight, characterized in that they have a tan / tan _{ratio of} greater than 3.37-0.0068.STSA in rubber blends.

In one embodiment of the invention, in addition to silicon, the carbon black may contain from 0.01 to 1 wt. nitrogen.

Silicon is introduced into the soot aggregates in the preparation process. For this purpose, for example, silicon-containing compounds may be incorporated into the carbon black feedstock. Suitable silicon-containing compounds may be organosilicon compounds such as organosilanes, organochlorosilanes, siloxanes and silazanes. In particular, silicone oils, silicon tetrachloride, siloxanes and silazanes may be used. Preferably, silanes and silicone oils may be used.

The starting compound has little effect on the binding of silicon atoms to the soot aggregates. By means of X-ray photoelectron spectrometry (XPS) and secondary ion mass spectrometry (SIMS) it is possible to show that the silicon atoms are bound by oxidation and are divided into soot aggregates. The oxygen bond consists predominantly of silica. Another proportion is the silanol groups. While the silanol groups are mainly found on the surface of the carbon black aggregates, the silica is uniformly distributed across the cross-section of the aggregate.

r r

In one embodiment of the invention, the silicon may be enriched in areas close to the surfaces of the carbon black aggregates.

The silicon-containing groups on the surface of the carbon black aggregates affect the interaction of the filler with the polymeric rubber components when incorporated into the rubber compositions. Bifunctional silanes, such as Si69® (bis (3-triethoxysilylpropyl) -tetrasulfan) from Degussa, as a silane coupling agent, can be admixed to the rubber mixtures to covalently bind the silanol groups of the carbon blacks to the blended polymers.

The mixtures prepared at the bearing surfaces of the carbon black containing silica of the invention show without the addition of a coupling agent increased the value of tan <f and impairment _of dances ^ ₀ compared to known carbon black of the same surface area and structure. These values correspond to a significantly improved wet slip behavior with a significantly reduced rolling resistance of the running surface. By adding bifunctional silanes, the rolling resistance of the rubber mixtures can be further improved, i.e. further reduced.

The carbon black according to the invention can be prepared by the retort carbon black method according to DE 195 21 565 A1.

The retorting soot method is used to oxidize pyrolysis of a carbon black feedstock in a reactor lined with highly non-combustible material. In such a reactor, three zones can be distinguished, which run one after the other along the reactor axis and gradually flow through the reaction medium.

The first zone, the so-called combustion zone, mainly comprises the reactor combustion chamber. Here, a hot process gas is produced in which the fuel, typically hydrocarbons, is combusted with an excess of preheated combustion air or other oxygen-containing gases. Natural gas may be used as fuel. Liquid hydrocarbons such as light and heavy fuel oil can also be used.

In one particularly preferred embodiment of the invention, a carbon black feedstock (carbon black oil) may also be used as a fuel.

The combustion of fuel is usually carried out in excess of oxygen. The excess air requires a complete conversion of the fuel and serves to control the soot quality. The fuel is introduced into the combustion chamber usually by means of one or more fuel pipes conveying the fuel to the combustion chamber.

In the second zone of the carbon black reactor, the so-called reaction or pyrolytic zone, soot formation occurs. Therefore, a soot feedstock, usually a so-called soot oil, is injected and mixed into the hot process gas stream. Based on the incompletely reacted amount of oxygen in the combustion zone, a plurality of hydrocarbons are fed in the reaction zone in excess. Therefore, soot formation normally occurs here.

If the soot oil is also used as a fuel, soot formation can already occur in the combustion zone. Additional soot particles can then be fed to the soot particles formed in the combustion chamber in the reaction zone.

The soot oil can be injected into the reactor in various ways. For example, an axial oil injection tube or one or more radial oil tubes, which are located in a plane perpendicular to the direction of flow on the r r of the reactor perimeter, is suitable. The reactor may have multiple planes with radial oil tubes along the flow direction. At the head of the oil pipe there are spray or spray nozzles through which the soot oil is mixed into the process gas stream.

By using soot oil and gaseous hydrocarbons such as methane as the soot feedstock, gaseous hydrocarbons can be injected separately from the soot oil by a custom set of gas tubes into the hot waste gas stream.

In the third zone of the soot reactor, the so-called quench zone, the formation of soot is interrupted by the rapid cooling of the soot-containing process gas. This prevents unwanted subsequent reactions. The interruption of the reaction is usually achieved by sprinkling water with suitable spray nozzles. Typically, the soot reactor has more sites along the water injection reactor, or "quenching", respectively, so that the soot delay time in the reaction zone can be varied. In the downstream heat exchanger, the residual heat of the process gas is used to preheat the combustion air and soot oil.

While the known retort carbon black methods aim to achieve complete combustion of the fuel in the combustion chamber or combustion zone, respectively, the method according to the invention is based on the preparation of carbon black in that incomplete combustion of fuel in the combustion zone generates carbon embryos. of the off-gas into the reaction zone, and there is the formation of soot-induced soot with the feedstock soot. However, the desirable incomplete combustion of fuel does not mean that the fuel is combusted in the absence of oxygen.

r r r ^ ^

The process according to the invention is also based on the excess of air or oxygen-containing gases in the combustion chamber. Here, K-factors between 0.3 and 1.2 can be applied as at conventional rates. Preferably, however, K-factors between 0.6 and 0.7 are used.

Different routes can be used to produce soot germs regardless of excess air. In one preferred variant of the process according to the invention, starting from liquid hydrocarbons as fuel, the fuel is combusted instead of natural gas in the reactor combustion chamber in an excess of air or oxygen-containing gases. Liquid hydrocarbons burn more slowly than gaseous because they are first converted into a gaseous form, that is, they must be converted into vapors. Thus, despite the excess oxygen, liquid hydrocarbons can also produce carbonaceous germs which, as long as sufficient time and a sufficiently high temperature are available, can also be further burned or, if cooled rapidly, can lead to an increase in larger carbon black particles. The formation of soot induced by the germs consists in bringing the germs formed immediately into contact with the carbon black oil during the combustion of the liquid hydrocarbons at an excess of oxygen, and thus starting the growth of the germs.

Another variant of the process according to the invention uses natural gas as fuel. The formation of the germs is achieved by selecting a gas flow rate from the fuel pipe or fuel pipes, respectively, so low as to deliberately achieve a poor mixing of natural gas into the hot combustion air stream. The formation of soot germs in poorly mixed flames is known, and luminous flames are also referred to because of the particles formed. In this process, it is also important, as with the combustion of liquid hydrocarbons, that the germs formed are brought into contact with the carbon black oil immediately after formation. If a larger combustion chamber or combustion zone is provided so that the germs in excess of existing oxygen can react in the combustion zone, and if full combustion is allowed in the combustion zone of the carbon black reactor, no germ-induced soot formation occurs.

The carbon black of the invention can be prepared by mixing the silicon-containing compounds described above into the carbon black feedstock and separately injecting them into the combustion chamber or pyrolysis zone of the reactor. The admixture of silicon oil containing compounds from the carbon black oil may be carried out in the form of a solution if the compounds are soluble in the carbon black oil or as an emulsion. These measures achieve the incorporation of the silicon atom into the primary carbon black particles. One or more oil pipes normally used for injection may be used to separately inject the silicon-containing compounds into the pyrolysis zone of the carbon black reactor.

The retort carbon black method is modified to prepare inverse carbon black. While the conventional retort carbon black method aims to completely burn fuel in the combustion chamber or combustion zone, respectively, the method according to DE 195 21 565 for preparing inverse carbon black consists in the formation of carbonaceous germs by incomplete combustion of the fuel in the combustion zone. they are transported by the hot off-gas into the reaction zone and there is the formation of soot induced by the germs with the soot feed. However, the desirable incomplete combustion of the fuel does not mean that the fuel is burned in the absence of oxygen. The process according to the invention is also much more based on an excess of air or oxygen-containing gases in the combustion chamber. In this case, K-factors between 0.3 and 0.9 can be used as with conventional soot rates.

Different routes according to DE 195 21 565 can be used to produce carbon blacks regardless of the excess air. In the preferred process variants, liquid hydrocarbons are used as fuels which are combusted instead of natural gas in the combustion chamber of the reactor with excess air or gases containing oxygen.

Liquid hydrocarbons burn more slowly than gaseous because they are first converted into a gaseous form, so they must be converted to steam when hot. Thus, in spite of the excess oxygen, liquid hydrocarbons can also produce carbonaceous germs which, as long as sufficient time and a sufficiently high temperature are available, can also be further burned or otherwise lead to an increase in the larger soot particles when rapidly cooled. The formation of carbon black induced by germs consists in bringing the germs formed immediately into contact with the carbon black oil during the combustion of the liquid hydrocarbons with an excess of oxygen, and thus the formation of the germs.

Another variant of the method according to DE 195 21 565 uses natural gas as a fuel. The formation of the germs is achieved by selecting a gas flow rate from the fuel pipe or fuel pipes, respectively, so low as to deliberately achieve a poor mixing of natural gas into the hot combustion air stream. The formation of soot germs in poorly mixed flames is known. particles also speaks of luminous flames. In this process, it is also important, as in the combustion of liquid hydrocarbons, that the germs formed are brought into contact with the carbon black oil immediately after formation. If a larger combustion chamber or combustion zone is set up so that the germs in excess oxygen can react in the combustion zone, complete combustion in the combustion zone of the soot reactor is allowed, so that germ-induced soot formation does not occur.

The two variants described can also be combined together. In this case, liquid hydrocarbons and natural gas or other gaseous fuels are fed in appropriate proportions simultaneously to the combustion zone. As liquid hydrocarbons, preferably oils, for example carbon black oil per se, may be used.

The process according to DE 195 21 565 therefore consists in using liquid and / or gaseous hydrocarbons as fuels in a combustion zone in which the oxygen is in excess relative to the hydrocarbons used, and is arranged, for example, to prevent the liquid hydrocarbon delay time or Insufficient mixing of gaseous hydrocarbons with combustion air produced soot germs, which are immediately contacted in the reaction zone with a carbon black feedstock, which is used in excess of oxygen; the resulting gas-carbon black reaction mixture is then cooled with jet water in the quenching zone and the carbon black thus formed is further processed in a conventional manner.

According to DE 195 21 565 the fuel contributes decisively to the formation of carbon black and is therefore referred to as the primary carbon black raw material in the following. The carbon black feedstock admixed to the reaction zone is thus referred to as a secondary carbon black feedstock and contributes in quantity to the largest portion of the carbon black formed.

The inverse carbon black according to DE 195 21 565 imparts a reduced rolling resistance and a comparable wet grip compared to the corresponding conventional carbon black. Furthermore, an AFM study (Atomic Force Microscopy) found that inverse carbon black exhibited a significantly rougher surface than the corresponding standard ASTM carbon black, thereby allowing improved bonding of the rubber polymer to the carbon black particles (see W. Gronski et al. "NMR Relaxation - A Method Relevant for Technical Properties of Carbon Black Filled Rubbers; International Rubber Conference 1997, Numberg, p. 107). Improved bonding of the rubber polymer leads to a decrease in rolling resistance.

Studies of abrasion of rubber compounds using inverse carbon blacks have shown that these carbon blacks provide improved rolling resistance under low loads. These rubber compounds exhibit increased abrasion under the high loads occurring on truck tires.

In one embodiment of the invention, improved inverse carbon blacks may be used which are characterized by particularly reduced wear under high loads.

Thus, retort carbon black with CTAB values of between 20 and 190 m ¹ / g and 24M4-DBP absorption between 40 and 140 ml / 100g with a tan / _c / tan ratio which can be incorporated into the SSBR / BR rubber mixture can be used.

tan y tan>> 2.76-6.7 x 10 * x CTAB, the tan je value being constantly lower than that of the ASTM carbon black with the same CTAB surface area and 24M4-DBP absorption.

These carbon blacks are characterized in that the distribution curve of the particle diameter of the carbon black aggregates exhibits an absolute skew coefficient of less than 400,000 nm.

These carbon blacks used according to the invention meet the same requirements as the known inverse carbon blacks in terms of the tand ₀ / tantalizing ratio and therefore lend a reduced rolling resistance when incorporated into rubber compounds prepared therefrom. However, they are characterized by a narrower particle size distribution of the aggregates compared to the known inverse carbon blacks. For the description of the particle size distribution of aggregates, the known rate of 'absolute skew coefficient (see: Lothar Sachs:' Statistische

Auswertungsmethoden, Springer-Verlag Berlin, 3rd ed., P.81 83). It represents a more appropriate description of the present problem of the aggregate size distribution curve shape as a limitation of the aggregate size by maximum and minimum values.

The term "absolute skew" refers to a deviation from the symmetrical size distribution of the aggregates. The oblique distribution curve is when one of the two descending branches of the distribution curve is elongated. If the left part of the curve is elongated, it is referred to as negative skew, that is, determining the absolute skew gives values below zero. If the right stretch of the curve is extended, there is a positive skew with values greater than zero. The known ASTM carbon black as well as the inverse carbon black and the carbon black according to the invention exhibit a positive skew of various molding.

Surprisingly, it has been found that the concept accepted by the prior art, the widespread size distribution of solidified carbon black aggregates lending rubber compositions with reduced rolling resistance, has no general validity. The improvement in the rolling resistance of the rubber compositions observed at inverse carbon blacks not r r is obviously dependent on the width of the aggregate distribution, but is mainly due to a greater roughening of the surface of the inverse carbon black and the associated bonding of the rubber polymer to the carbon black surface.

In contrast to the known inverse carbon blacks with their relatively wide aggregate size distribution, this abrasion resistance can now be improved according to the invention by limiting the width of the aggregate distribution. In particular, the proportion of carbon black aggregates with large particle diameters must be reduced if the carbon black is to lend, at the same time, an improved abrasion resistance in addition to the reduced rolling resistance. This is then the case where the absolute slant coefficient of the aggregate size distribution is less than 400,000 nm *, preferably less than 200,000 nm. The coefficient of absolute inclination of the inverse carbon black known from DE 195 21 565 lies above 400 000 nm ', while the coefficient of absolute inclination of standard carbon blacks is below 100 000 nm *

The coefficient of absolute inclination of the soot aggregate size distribution can be mediated by means of a disk centrifuge and a corresponding evaluation of the measured values. The soot samples to be investigated are dispersed in aqueous solution and are distributed according to the particle size of the disk centrifuge: the larger the particles, the greater their mass, the faster the soot particles move outwards due to centrifugal force in the aqueous solution. In doing so, they pass through a light shutter, by means of which the extinction is recorded as a function of time. From these data, the aggregate size distribution is calculated, i.e. the abundance as a function of the particle diameter. From this, the absolute skew factor AS is calculated as follows:

*, - ^ 15

Hi P)

AS = ___________ k

Σ H <i · /

Here, H 1 denotes the frequency with which the particle diameter x ₆ occurs. x is the diameter of those particles whose mass corresponds to the average particle weight of the carbon black aggregates, x is also calculated by the aggregate size distribution. The summations in the above formula must be made in the range from 1 nm to 3000 nm at equidistant intervals of one nanometer each. Any missing measured values are calculated by linear interpolation.

Inverse carbon black according to the invention can be prepared by the generation method described in DE 195 21 565. According to this method, inverse carbon black is prepared in a soot reactor comprising a combustion zone, a reaction zone and a quench zone along the reactor axis. In the combustion zone, primary soot feedstocks are produced in the oxygen-containing gases by a stream of hot waste gases. This hot gas stream is passed from the combustion zone through the reaction zone to the quench zone. In the reaction zone, the secondary carbon black feedstock is mixed into the hot waste gas. The formation of soot is stopped in the quench zone by spraying water. The primary carbon black feedstock used is oil, an oil / natural gas mixture or natural gas itself. The combustion of the primary carbon black in the combustion zone is carried out so as to form germs of soot with which the secondary carbon black can be brought directly into contact.

In order to obtain the carbon black according to the invention, this method must be carried out in such a way that the carbon black formed exhibits an aggregate size distribution with an absolute coefficient - / IC -.

This is achieved, for example, by increasing the supply of combustion air, primary or secondary raw material.

The process described is not limited by the particular geometry of the reactor. It can in turn be adapted to different types of reactors and reactor sizes. The desired formation of germs in the combustion zone can be set by the skilled person by various measures. Possible variables affecting the optimization of seed formation when using oil as a fuel are the combustion air / oil ratio, the type of fuel atomizer used and the size of the oil droplets to be sprayed. As fuel atomizers, pressure atomizers (single-atomizers) can also be used, as well as two-component atomizers with internal or external mixing, and the atomizing medium used can be compressed air, water vapor, hydrogen, inert gas or also hydrocarbon gas. The above-described combination of liquid fuel and gaseous fuel can also be realized by using gaseous fuel as a liquid fuel atomizing medium.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail by way of an example of embodiment shown in the drawing, in which:

Fig. 1 shows a longitudinal section through a reactor used for preparing carbon black according to the invention, FIG. 2 The ratio tan / tand versus STSA surface where b is ASTM carbon black; * means inverse carbon black; A is Si-carbon black; o is inverse Si-carbon black; and

... means the boundary line of inverse Si-carbon black.

Examples of the invention

The carbon black according to the invention has been prepared in the reactor shown in Figure 1. This soot reactor 1 consists of a combustion plant in which hot soot oil pyrolysis 13 is produced; the excess air flow is fed through the axial combustion can to the waste gas chambers by combustion of oxygen oil. Fuel Fuel Pipeline 3 germ chamber 2 to optimize in the axial direction.

pipe 3

The inflow is carried out by combustion penetration takes place

2, on and off the formation of soot-induced combustion air with a conical aperture tapered at the front wall

Combustion chamber 2 tapered

Second

After 5, the reaction mixture expands into the reaction chamber 6.A, various injection positions

B and C designate soot oil into the hot process gas by means of oil tubes 2. Oil tubes T have suitable spray nozzles on their heads. At each injection position, four injectors are disposed around the perimeter of reactor 2.

For the process according to the invention, the important zones are the combustion zone, the reaction zone and the quench zone

- are characterized in figure 1 by the Roman numerals I to III. They cannot be sharply separated. Their axial expansion always depends on the position of the fuel pipe 3, the oil pipes 7 and the quench water pipes 15.

r «

The dimensions of reactor 1 used are k

available from the following overview: the biggest average combustion chamber 530 mm length of combustion chamber to the tapered pLACE: 1525 mm length conical part combustion chamber: 1160 mm average constricted places: 140 mm length constricted places: 230 mm average reaction chamber: 240 mm position oil tubes (Tubes)

A: + 110mm

B: - 150mm

C: - 410mm

Pipe position Collating waters (Quench) and 1: 1355mm

2: 2900 mm u measured before entering the restricted area (+: after entering, before entering).

All the carbon black prepared in the described reactor was pearled prior to characterization and incorporation in a known manner.

Natural gas and carbon black oil 13 with a carbon content of 91.4% by weight were used as fuel 9 for the preparation of the carbon black according to the invention. and hydrogen content

6.1 wt.

The reaction parameters for the preparation of the carbon black according to the invention are shown in the carbon black table R 1, R 2 and R 3 as well as

1. Comparative carbon black was prepared

A4496. In preparation, silicone oil 14 was added to the carbon black as a silicon-containing compound.

On the carbon black according to the dosage of the present invention R. to be done so

R3 was carbon black containing 5.6 wt. silicon

Table T.

Parameters of the carbon black reactor

Reactor parameters WITH A4496 adze R.í R _p ri parameter unit Combusted air NRN / h 3000 2700 2700 Temperature of combustion air ° C 560 450 450 Fuel (natural gas) Nm / h 237 - Fuel oil kg / h 200 200 Carbon black oil kg / h 640 360 365 Temperature of the soot oil ° C 131 127 127 Silicone oil 1 / h 36 36 location 4 x A 4 x A 4 x A

soot oil injector

Additive concentration g / 1 1 1 1 number 1 / h 2 14 11.5 quencher mm 1355 1355 1355 position

Measured before entering the restricted area. Carbon black R ₇ , R _z and A4496 are additionally beaded. Carbon black R is dry beaded.

The analytical characteristics of the carbon black on the prepared carbon black were determined according to the following standards and are shown in Table 2:

STSA surface area: ASTM D-5816 DBP absorption: ASTM D-2414 24M4-DBP absorption: ASTM D-3493 BET surface: ASTM D-4820 CTAB surface area: ASTM D-3765

Table 2:

Analytical characteristics of carbon black

DBP 24M-DBP Si STSA

Carbon black fml / 100g] [ml / 100g] [wt%] [rn / g]

CTAB [rrf / h]

N220 114 98 0 107 110 A4496 112 96 0 108 110 ^R 1 103 94 5.6 110 121 102 96 5.6 112 122 R _s 118 91 5.6 103 113

Example of use

R Carbon black _from R ₃ and the comparative carbon black N220 and A4496 were used in the preparation of rubber compositions. The viscoelastic properties of rubber compounds were determined.

The viscoelastic properties of the rubber compounds reinforced with these carbon blacks were determined according to DIN 53513. In particular, the loss factors tanS at 0 ° C and at 60 ° C were determined.

Table 3:

Test formula SSBR / BR

Mixture component Contents [Phr] SSBR 96.0 BR 30.0 blacks 80.0 ZnO RS 3.0 stearic acid 2.0 aromatic oil 10 6 PPD 1.5 wax 1.1 CBS 1.5 DPG 2.0 TMTD 0.2 sulfur 1.5

silane coupling agent Si 69 optional

The SSBR rubber component is a polymerized SBR copolymer solution having a styrene content of 25 wt. and a butadiene content of 75 wt. The vinyl content of butadiene is 67%. The copolymer contains

37.5 phr of oil and sold under the trade name Buna VSL 5025-1 by Bayer AG. Its Mooney viscosity (ML 1 + 4/100 ° C) is about 50.

The BR rubber component is cis 1,4 polybutadiene (Neodymtype) having a cis content of at least 96% by weight, a trans content of 1.42% by weight, a content of 1.21% by weight. and Mooney viscosity 44 + 5. This component is sold under the trade name Buna CB 24 by Bayer AG.

The aromatic oil used is Naftolen (R) ZD, Chemmetall. The PPD content of the test formulation is Vulkanox (R) 4020 and the CBS content is Vulkacit (R). all from Bayer AG. The wax used is a G35 protector from HB-Fuller GmbH. ZnO RS is zinc oxide manufactured by Carl Ansperger GmbH and Co. KG.

The incorporation of the carbon black into the rubber mixture is carried out in three stages as in the following tabular overview.

Stage 1

incorporation

mixing aggregate friction Werner & Pfleiderer GK 1.5 N 1: 1, 11 speed of punch pressure 70 min * 5,5 bar empty volume filling degree flow temperature 1.6 I 0.73 80 C

Stirring procedure up to 1 min to 3 min to 4 min min

Buna VSL 5025-1 + Buna CB 24% carbon black + ZnO RS + stearic acid + Naftolen ® ZD + Si 69® carbon black, Vulcan 4020 + protector G35 cleaning up to 6 min.

batch temperature storage 150 -16 ° C 24 h at room temperature

Stage 2

Incorporation Mixing unit Filling level Flow temperature Stirring procedure 0 to 2 min 2 to 5 min min as for stage 1 up to

0.71 ° C interrupt batch stages 1 maintain batch temperature 160 ° C by varying the speed of the exit batch temperature 160 ° C storage 4 h / RT

degree Incorporation Mixing unit Filling level Flow temperature Number of rotations Mixing procedure 0 to 2 min how to grade 1 up to 0.69 50'C 40 batch stages 2 + Vulkacit® CZ + Vulkacit®® and Vulkacit® Thiuram + sulfur 1 min discharging and forming a laboratory rolling mixer. For homogenization then: Separate 3x left and 3x right and flip as well 8 x for narrow cylinder slot (1 mm) and 3 x For a wide roll gap (3.5 mm), slide down and finally pull out the layer.

Attached determination of rubber technological properties, ie Shore hardness, voltage values M100 and M300, rebound at 0 and 60 ° C as well as the loss factor tan at 0 * 0 and at 60 ° C and the dynamic modulus of expansion / E * / at 0 ° C are carried out according to the above standards. The measurement conditions for viscoelastic properties are summarized in Table 4.

r t r · r e ·

Table 4:

Determination of viscoelastic properties according to DIN 53513 vulcanization of test specimens vulcanization temperature

Vulcanization time

Form test pieces shape length diameter number

Testing machine

Type / manufacturer

Type of load

Mean force amplitude Dynamic force amplitude Test frequency Test run

165 [deg.] C

T + 5 min (T: DIN 53529) «fd cylindrical mm mm

830 / MTS stretching

N + 25 N

Hz min, then dynamic load at 16 Hz for 2 min and subsequent measurement

The median value was always used on five test pieces.

The results of the rubber technology examinations are shown in Table 5. Compared to the comparative carbon blacks, the carbon blacks of the present invention lend a reduced loss factor at 60 ° C and an increased loss factor at 0 ° C without a binder to the rubber blend. Addition of Si69® can further reduce the loss factor at 60 ° C. Thus, tires prepared from rubber compounds of this kind are expected to have improved wet slip behavior while reducing rolling resistance.

Dry carbon black R leads to a further decrease in tan at 60 ° C compared to wet carbon black R.

The preferred behavior of the carbon black according to the invention is shown in Figure 2.

Figure 2 shows these carbon blacks refused their relationship Tania ₀ / dances £ _o versus STSA - surface. Both carbon blacks according to the invention show a significantly higher tan ratio, i.e. a steeper temperature profile of the loss factor, for the same STSA surface.

The soot area according to the invention can be clearly distinguished from conventional soot. It lies in Figure 2 above the cut-off line, which is given by the calculation tanJ / tan / = 3.37 - 0.0068.STSA.

Claims (5)

PATENT CLAIMS Carbon black, having an STSA surface area determined by ASTM D-5816 of between 20 and 180 m / g, a 24M4DBP absorption by ASTM D3493 of between 40 and 140 ml / 100 g and a specific BET surface area determined by ASTM D -4820 between 20 and 250 m * / g, a silicon content of 0.01 to 20 wt.%, based on the total weight, characterized in that the rubber mixtures have a ratio of Tanji / TANJ ^- ^ greater than 3.37 to 0, 0068.STSA. Second soot according to claim 1 v y z n acing by that except silicon contain still 0.01 % to 1 wt. nitrogen. Third process preparation carbon black according to of claim 1 by oxidative pyrolysis of carbon-containing carbon black feedstocks, characterized in that the fuel is a carbon black oil, an oil, an oil / natural gas mixture or a natural gas as such and the combustion of the fuel takes place to form germs and the carbon black is immediately brought into contact with such carbon black germs and that silicon-containing compounds are admixed with the carbon-containing carbon black raw materials. A process for preparing carbon black according to claim 3 by oxidative pyrolysis of carbon-containing carbon black feedstocks, characterized in that the silicon-containing compounds are injected into the combustion chamber or reaction chamber of the carbon black reactor. with Process according to either of Claims 3 and 4, characterized in that organosilicon compounds such as organosilanes, organochlorosilanes, silicic acid esters, siloxanes or silazans are used as silicon-containing compounds. Method according to any one of claims 3 to 5, characterized in that the distribution of the silicon in the carbon black is influenced by the variation in the mixing of the silicon-containing compounds into the carbon black oil. Use of the carbon black according to claim 1 as reinforcing carbon black in rubber compounds, in particular for tires with reduced rolling resistance and improved wet slip behavior.