AND METHOD OF PRODUCTION THEREOF

FIELD OF INVENTION

The invention relates to rubber industry, in particular to rubber compounds, namely to processing additives for rubber compounds and a method of producing these processing additives.

The invention may be used in manufacturing automotive tires and various rubber goods items.

Processing additives are used for targeted adjustment of processing properties of rubber compounds, including decrease in viscosity and increase in filler dispersion degree, which allows improving treatment of the rubber compounds and decreasing temperature, time and energy consumption during production thereof, and also provides activation and structuration of components for some compositions of rubber compounds, while maintaining and even improving operational characteristics of the rubber.

BACKGROUND OF THE INVENTION

Processing additives for rubber compounds based on salts of carboxylic acids are the most known and commonly used ones.

Patent document US2016024280 published on January 28, 2016, IPC C08C19/42, C08K5/101 , C08K9/025, describes a processing additive containing salts of metals (sodium, potassium, calcium, magnesium, barium, zinc, cadmium, ferric, chromium, cobalt) and carboxylic acids like higher fatty acids, e.g., double aluminum salts of fatty acids.

The described additive possesses all target properties, namely, it provides decreasing viscosity of rubber compounds, increasing filler dispersion degree, as well as activating and structuring effect on components of rubber compounds. Addition of this processing additive to a rubber compound for tire treads based on diene rubbers provides tire treads having improved tensile strength properties and good traction characteristics on a wet road, while maintaining a comparable rolling resistance level. However, obtaining this additive involves a complicated technology and causes sufficient economical load, as the target product is obtained in liquid phase of a multi-stage process that includes preparation of an alkali salt of a fatty acid at one stage, preparation of a metal salt in a solution, e.g., aluminum sulphate in alkaline solution at another stage, then combining these two solutions during vigorous agitation and heating and obtaining the required product as a result of chemical reaction between the reactants with further multiple rinsing and extended drying.

Patent document LIS2015274939 published on October 1 , 2015, IPC C08K13/02, C08K3/36, C08K5/098, C08K5/5415, describes a processing additive that may be obtained by a process having a less number of stages. However, this process is also technologically complicated and involves multilevel control. This processing additive is selected as a closest prior art and it contains at least one metal carboxylate represented by formula (RCOO) _P M ^(p+n)+ (OH) _n , where:

R is a hydrocarbon group having 1 to 25 carbon atoms;

M is selected from a group including aluminum, barium, cadmium, calcium, cobalt, iron, lithium, magnesium, sodium, tin, zinc and zirconium; p + n is equal to valence of M and each of n and p is an independently selected integer in range of 0 to (p + n).

This additive possesses all above-mentioned target properties and provides decreasing Mooney viscosity of rubber compounds, streamlines treatment thereof, increases elasticity modulus of the rubber compounds and assures activation and structuration effect on components of the rubber compounds.

Such a processing additive, e.g., in form of aluminum tri-(n-octanoate) is obtained under conditions of liquid-phase chemical interaction (where a Dean-Stark distiller is used) between aluminum isopropoxide and a fatty acid (that is octane acid) in toluene solution at 140-150°C followed by vacuum removal of residual solvent, which disposal is a great problem for chemical plants, as this solvent is not environment-friendly. Thus, the solution of LIS2015274939 requires implementation of a number of environmental safety actions and deteriorates economical characteristics of the target product. As it can be understood from the above-stated, the known chemical processes for manufacturing such additives for rubber compounds are based on liquid-phase processes. However, high fluidity of these phases causes problems, as leaktight integrity of reactors shall be maintained, release of reaction products shall be controlled and waste shall be properly handled. All these factors are negative in view of recent tendency of keeping environment intact.

SUMMARY OF THE INVENTION

The claimed invention relates to task of obtaining a processing additive that is based on such reactants and under such conditions of chemical interaction, which are able to provide target properties of the product using an environmentally safer production method.

The technical effect attained by the invention is obtaining the processing additive by a simpler and less time-consuming process with no use of environmentally undesirable solvents. The additive possesses all target properties, including decrease in viscosity of rubber compounds during treatment, improves distribution of components of rubber compounds, and facilitates improvement of traction between wet road surface! and tires manufactured of rubber compounds with the additive.

This task is solved by providing the processing additive for rubber compounds, which contains metal salts of carboxylic acids and represents a two-component product of mechanical and chemical activation of at least one natural mineral containing compounds of metals from a group including aluminum, calcium, iron, zinc, sodium, potassium and magnesium, and at least one carboxylic acid selected from a group including fatty acids and resin acids having 10 to 28 carbon atoms, where the first component contains salts of at least one of the mentioned acids and metals of at least one of the mentioned minerals, and the second component contains at least one of the mentioned minerals disintegrated to ultra-fine particles during the mentioned mechanical and chemical activation.

According to the claimed invention, the developed processing additive improves target properties including increase in filler dispersion degree for a rubber compound and distribution of other components owing to decreasing viscosity of tire rubber compounds containing the claimed additive, and provides improvement of endurance and hysteresis characteristics of the rubber.

An embodiment of the claimed invention involves the first component additionally containing at least one of the mentioned acids, where weight ratio between the mentioned salts and the additional acids is 10:90 to 90:10, correspondingly, which facilitates improving degree of treatment of rubber compounds and decreasing power consumption during production thereof, while maintaining all target properties of the proposed processing additive.

An embodiment of the claimed invention involves the additive containing 40%wt to 70%wt of the mentioned first component and 30%wt to 60%wt of the mentioned second component, which assures maintaining structural stability of the target product and its ability to improve traction between tires and wet road surface, while maintaining all target properties of the proposed processing additive.

An embodiment of the claimed invention involves the second component mainly containing 15%wt to 35%wt of SiC>2, 3%wt to 12%wt of AI2O3, 3%wt to 20%wt of CaO, Fe(ll) and Fe(lll) corresponding to 0.05%wt to 10.0%wt of Fe2Os, 0.0001 %wt to 10.0%wt of ZnO, 0.1 %wt to 5.0%wt of Na2O and K2O, 1 %wt to 5%wt of MgO, according to X-ray fluorescence data (metal contents are calculated based on oxides thereof in relation to total weight of the proposed processing additive). This approach provides obtaining all target properties of the proposed processing additive.

In addition, the task in hand is solved by providing the method of obtaining the processing additive for rubber compounds, the method involving chemical interaction between a carboxylic acid and a metal-containing agent until a corresponding salt is formed. According to the invention, the chemical interaction is performed using at least one acid selected from a group including fatty acids and resin acids having 10 to 28 carbon atoms, used as the carboxylic acid, during contiguous mechanical and chemical activation of the acids and at least one natural mineral based on metal compounds of aluminum, calcium, iron, zinc, sodium, potassium and magnesium, used as a metal-containing agent, in order to obtain a two-component product, where the first component contains corresponding formed salts, and the second component contains a natural mineral disintegrated to ultra-fine particles during the mentioned mechanical and chemical activation.

The developed method allows obtaining the processing additive possessive of all above-mentioned target properties and providing environmental safety by avoiding use of environmentally undesirable solvents during simpler and less time-consuming process.

To provide a product of stable structure and high level of target properties, chemical interaction, according to the invention, is expedient to be held at weight ratio of the mentioned acid and the mentioned natural minerals in range of (0.5 to 1.5) : (0.5 to 2.0), correspondingly.

To provide consistently high parameters of the processing additive related to improving traction between tires and wet road surface and to assure all target properties of the proposed processing additive, it is useful, according to the invention, to use the following minerals selected separately or in combination as the mentioned natural minerals: zeolite, porcellanite, muscovite, gibbsite, calcite, dolomite, feldspar, basalt, montmorillonite, bentonite, which mainly have the following composition calculated based on oxides: 30%wt to 70%wt of SiC>2, 5%wt to 24%wt of AI2O3, 7%wt to 36%wt of CaO, Fe(ll) and Fe(lll) corresponding to 2%wt to 15%wt of Fe2Os, 0.00001 %wt to 5.0%wt of ZnO, 1 %wt to 10%wt of Na2O and K2O, 1 %wt to 10%wt of MgO.

To provide strength and dynamics characteristics of rubber mix items and to assure all target properties of the proposed processing additive, it is useful, according to the invention, to perform the mentioned chemical interaction during production of the processing additive for rubber compounds in presence of at least one additional compound selected from a group including oxides and hydroxides of calcium, aluminum, zinc, sodium, iron, magnesium, amounting to 3%wt to 15%wt of the used natural mineral.

According to the invention, it is desirable that size of particles of the used natural minerals exposed to mechanical and chemical activation is to be not larger than 3.0 millimeters, which facilitates formation of the disintegrated mineral with more uniform dispersion within a shorter period of time, along with assuring all target properties of the proposed processing additive.

According to the invention, it is economically expedient to perform the mechanical and chemical activation until size of at least half of amount of the particles does not exceed 1.5 micrometers, which indicates that the process is complete and the target product is obtained with assuring all target properties of the proposed processing additive, as well as that energy-consuming equipment may be switched off.

Other targets and advantages of the claimed invention shall be clear form the following detailed description of the claimed processing additive for rubber compounds, the method of obtaining thereof, and particular examples of implementation of the method.

DETAILED DESCRIPTION

According to the invention, the claimed processing additive for rubber compounds is a two-component product of the following solid initial reactants: at least one natural mineral containing compounds of metals from a group including aluminum, calcium, iron, zinc, sodium, potassium and magnesium, and at least one acid selected from a group including solid fatty acids and resin acids having 10 to 28 carbon atoms. According to the invention, the mentioned initial reactants are modified by mutual mechanical and chemical activation thereof.

The first component of the two-component product corresponds to solid salts based on an acid selected from a group including fatty acids and resin acids having 10 to 28 carbon atoms and a natural mineral containing compounds of metals from a group including aluminum, calcium, iron, zinc, sodium, potassium and magnesium. In other words, content of the first component corresponds to salts of metals of the mentioned natural mineral and the at least one mentioned acid. There is a possible implementation option of the first component, where it additionally contains at least one of the mentioned acids and weight ratio between the salts and the additional acids is 10:90 to 90:10, correspondingly. Providing the first component in various options of its content allows adjusting effectiveness of the claimed processing additive that effects degree of treatment of rubber compounds and power consumption during production of rubber compounds, as well as wet road traction properties of tires made of rubber compounds with such additive.

As for fatty acids and resin acids having 10 to 28 carbon atoms, the following acids are meant, as an example: mid fractions of fatty acids like lauric acid and tridecilyc acid, higher fatty acids like myristic acid, palmitic acid, stearic acid and cerotis acid, mixtures of different fractions of fatty acids or mixtures of fatty acids with oxyethylated C15-C22 fatty acid fractions, mixtures of vegetable and/or synthetic fatty acids and fatty acids of tall oil with content of resin acids not less than 30% at ratio in range of 90:10 to 50:50.

The second component of the two-component product corresponds to powdered product of the at least one mentioned natural mineral disintegrated to ultra-fine particles (in this case, at least half of them have size not larger than 1 .5 micrometers) during mechanical and chemical activation of the mentioned reactants. As an example, the following composition of the second component may be implemented: 15%wt to 35%wt of SiC>2, 3%wt to 12%wt of AI2O3, 3%wt to 20%wt of CaO, Fe(ll) and Fe(lll) corresponding to 0.05%wt to 10.0%wt of Fe2Os, 0.0001 %wt to 10.0%wt of ZnO, 0.1 %wt to 5.0%wt of Na2O and K2O, 1 %wt to 5%wt of MgO, according to X-ray fluorescence data (calculated based on oxides in relation to total weight of the additive).

Preferably, the two-component product according to the invention contains 40%wt to 70%wt of the first mentioned component and 30%wt to 60%wt of the second mentioned component.

According to X-ray diffraction analysis data, the claimed processing additive in form of the two-component product as described above structurally consists of amorphous phase that is the first component, and crystal phase that is the second component.

On parameter of the claimed processing additive is softening temperature that is in range of 70°C to 130°C.

As for mechanical and chemical activation, it means a process of transition of a solid substance into reactive state due to application of mechanical energy during disintegration, in this case to ultra-fine particles having multiple defects induced in crystal lattice of the natural minerals. The lattice defects in the natural minerals cause and activate their reaction ability and facilitate further reactions with an active agent, in this case with a solid fatty acid or a resin acid, until salts of the first component are formed.

As for ultra-fine particles, size of these particles is smaller than 40 micrometers and larger than approximately 0.75-0.1 micrometers. In this case, the product is characterized by that size of at least half of amount of the particles is smaller than 1 .5 micrometers.

The claimed processing additive possesses all the above-mentioned target properties, which are necessary for targeted adjustment of processing properties of the rubber compounds, including decrease in Mooney viscosity of the rubber compounds down to approximately 7%, increase in filler dispersion degree, and improvement of distribution of components in the rubber compounds. The additive assures activating and structuring effect on components of the rubber compounds.

Moreover, owing to content between 30%wt and 60%wt of the natural minerals in form of ultra-fine particles, the additive provides improvement of traction between tire rubber and wet road surface and increase in strength and hysteresis characteristics of the rubber produced using the claimed additive.

The proposed processing additive for rubber compounds may be obtained by the method comprising chemical interaction between at least one carboxylic acid selected from a group including fatty acids and resin acids having 10 to 28 carbon atoms, and a metal-containing agent, until a corresponding salt is formed. There is a possible implementation option for the method, where the chemical interaction of the mentioned reactants is performed in presence of at least one additional oxide/hydroxide of calcium, aluminum, zinc, sodium, iron or magnesium, amounting to 3%wt to 15%wt of the used natural mineral. Use of this method implementation option provides more effective adjustment of processing properties of the rubber compounds and facilitates increasing strength and dynamics characteristics of rubber articles to be made of rubber compounds with this additive. According to the invention, natural minerals based on compounds of aluminum, calcium, iron, zinc, sodium, potassium and magnesium, e.g., zeolite, porcellanite, muscovite, gibbsite, calcite, dolomite, feldspar, basalt, montmorillonite and bentonite are used as the metal-containing agent. When used separately or in combination, the mentioned natural minerals may provide the following content of the metals, if calculated based on oxides: 30%wt to 70%wt of S iC>2, 5%wt to 24%wt of AI2O3, 7%wt to 36%wt of CaO, Fe(ll) and Fe(lll) corresponding to 2%wt to 15%wt of Fe2Os, 0.00001 %wt to 5.0%wt of ZnO, 1 %wt to 10%wt of Na2O and K2O, 1 %wt to 10%wt of MgO.

According to the invention, the mentioned chemical interaction is performed during contiguous mechanical and chemical activation of initial reactants, while providing ultra-fine grinding the mentioned natural minerals. The mechanical action applied to solid particles of the natural minerals causes dispersing and emerging defects in lattice thereof.

The dispersed solid natural minerals have greater surface and accumulate defects in lattice of the solid natural minerals, which increase their reaction ability and cause further reactions with solid fatty acids and/or resin acids with formation of corresponding salts.

It was also found that, according to the invention, the chemical interaction between natural minerals and carboxylic acids during the mechanical and chemical activation occurs mainly on surface of the mineral particles, where various functional groups, mainly oxygen-containing reaction centers are formed. Based on the formed functional groups and oxygen-containing reaction centers in the minerals, interaction with activated solid acids also occurs. Thus, surface modification of the grinded natural mineral particles and solid acids takes place during the described mechanical and chemical activation. This modification is accompanied by increase in reaction ability thereof. The attained increase in reaction ability facilitates speeding up rate of formation of the target product. The natural minerals after ultra-fine grinding obtain form of particles smaller than 40 micrometers and larger than approximately 0.75-0.1 micrometers. The claimed method is economically expedient, if the grinding is finished, when size of at least half of amount of the dispersed mineral particles is smaller than 1 .5 micrometers.

To implement the described chemical interaction under described conditions during the mechanical and chemical activation, known equipment may be used like planetary mills, flow mills, ball mills, disintegrators, jet mills, as well as VMX series vertical ultrafine grinders and impact mills, which provide the mechanical and chemical activation of the mentioned natural minerals in presence of acids as described above. Effectiveness of mechanical impact for the natural minerals depends on selected equipment and affects speed and duration of the mechanical and chemical activation process. Therefore, depending on the selected equipment type, duration of the process may vary between 0.2 and 2 hours.

Natural minerals mainly with particle size not exceeding 3.0 millimeters are fed into the reaction zone and exposed to the mechanical and chemical activation. The mechanical and chemical activation is performed until not more than 5%wt of particles having size over 0.12 millimeters is contained in the disintegrated product. At the same time, size of at least half of amount of the particles does not exceed 1 .5 micrometers.

The chemical interaction under described conditions during the mechanical and chemical activation results in obtaining a two-component product. The first component of the obtained product mainly corresponds to formed salts of metals contained in the natural mineral selected as an initial reactant and modified during the mechanical and chemical activation, and to at least one acid also selected as an initial reactant and modified during the mechanical and chemical activation. The second component represents a powdered product of the natural mineral selected as an initial reactant that was disintegrated to ultra-fine particles and modified during the mechanical and chemical activation.

In some cases, the first component additionally contains an additional acid presented in the initial reaction mass and weight ratio between the formed salts and the acids is usually 10:90 to 90:10, correspondingly. According to the invention, the mentioned chemical interaction may be performed at weight ratio of the mentioned acid and the mentioned natural minerals in range of (0.5 to 1.5) : (0.5 to 2.0), correspondingly. Proportions selected in the mentioned range depend on chemical composition and physical properties of the natural mineral and quantitative content of metals therein, and these proportions affect speed and duration of the process. Mainly, the mechanical and chemical activation process and the chemical interaction are performed until at least half of amount of the second component particles being smaller than 1.5 micrometers are formed. As it was found during studies, performing the process within the mentioned weight ratio of the reactants yields reaction mass containing 40%wt to 70%wt of the first mentioned component and 30%wt to 60%wt of the second mentioned component, when the mentioned dispersity is reached.

The obtained two-component product may have the following total composition of metal compounds calculated based on oxides: 15%wt to 35%wt of SiC>2, 3%wt to 12%wt of AI2O3, 3%wt to 20%wt of CaO, Fe(ll) and Fe(lll) corresponding to 0.05%wt to 10.0%wt of Fe2Os, 0.0001 %wt to 10.0%wt of ZnO, 0.1 %wt to 5.0%wt of Na2O and K2O, 1 %wt to 5%wt of MgO, according to X-ray fluorescence data.

It shall be noted that implementation of the chemical interaction during the mechanical and chemical activation provides a number of advantages over standard thermal methods of liquid media reactions, which currently are widely used in production of processing additives, including technologies described in the above-mentioned patent documents. Main advantages of the proposed method are relatively simple implementation of the process that is held in solid phases, thus excluding environmentally dangerous solvents, and less duration of the overall process.

When used as a processing additive for rubber compounds, the obtained product provides targeted adjustment of processing properties of the rubber compounds, including decrease in viscosity of rubber compounds, increase in filler dispersion degree, improvement of distribution of components of rubber compounds, and activation and structuration effect on components of rubber compounds. Moreover, the obtained product provides improvement of traction between tire rubber and wet road surface, while increasing or maintaining strength and hysteresis characteristics of the rubber produced using this product. Application of mechanical and chemical methods during production of this product allows providing technology at a new level of environmental safety.

Example 1

A natural mineral named porcellanite had chemical composition represented mainly by silica and calcium-containing compounds, and a natural mineral named zeolite had the following chemical composition: mainly 71.5% of SiC>2, 13.1 % of AI2O3, 0.9% of FesO ₄ , 2.1 % of CaO, 1 .07% of MnO, 0.2% of TiO ₂ , 5.03% of K2O + Na ₂ O.

Porcellanite and zeolite minerals with particle size not exceeding 2 millimeters amounting to 11 grams and 5 grams, correspondingly, and stearic acid amounting to 11 grams were carefully mixed and loaded into a grinding cylinder having volume of 40 cm ³ of Fritsch Pulverisette 7 planetary mill (Germany). The following grinding mode was used: planetary disk rate of 600 s ^-1 , grinding time, including cooling, of 60 minutes, use of 145 balls having diameter of 5 millimeters.

The obtained product was studied using laser analyzer of particle size ANALYSETTE 22 NANOTEC (FRITSCH). Size of particles D50 was 1.4 micrometers (i.e., size of 50% of particles did not exceed 1 .4 micrometers).

Softening temperature for the obtained product determined by “ring and ball” method was 87°C.

Example 2

A natural mineral named basalt had the following chemical composition: mainly 45- 52% of SiO ₂ , 15-18% of AI2O3, 8-15% of Fe ₃ O ₄ , 6-12% of CaO, 5-7% of MgO. A natural mineral named zeolite had the following chemical composition: mainly 71.5% of SiO ₂ , 13.1 % of AI2O3, 0.9% Fe ₃ O ₄ , 2.1 % of CaO, 1.07% of MnO, 0.2% of TiO ₂ , 5.03% of K2O + Na ₂ O.

Basalt and zeolite minerals with particle size not exceeding 2 millimeters amounting to 11 grams and 4 grams, correspondingly, and stearic acid amounting to 11 grams were carefully mixed and loaded into a grinding cylinder having volume of 40 cm ³ of Fritsch Pulverisette 7 planetary mill with air cooling (Germany). The following grinding mode was used: planetary disk rate of 600 s ^-1 , grinding time, including cooling, of 80 minutes, use of 145 balls having diameter of 5 millimeters.

The obtained product was studied using laser analyzer of particle size ANALYSETTE 22 NANOTEC (FRITSCH). Size of particles D50 was 1.3 micrometers (i.e., size of 50% of particles did not exceed 1 .3 micrometers).

Softening temperature for the obtained product determined by “ring and ball” method was 96°C.

Example 3

A natural mineral named zeolite that had the following chemical composition: mainly 71.5% of SiO ₂ , 13.1 % of AI2O3, 0.9% Fe ₃ O ₄ , 2.1 % of CaO, 1.07% of MnO, 0.2% of TiO ₂ , 5.03% of K ₂ O + Na ₂ O and particle size not exceeding 3 millimeters and zinc oxide amounting to 38.0 grams and 4.2 grams, correspondingly, as well as stearic acid amounting to 30.2 grams were carefully mixed and loaded into a grinding cylinder having volume of 250 cm ³ of Aktivator planetary mill with water cooling (Novosibirsk). The following grinding mode was used: planetary disk rate of 700 s ^-1 , grinding time of 20 minutes, use of 160 balls having diameter of 10 millimeters.

The obtained product was studied using laser analyzer of particle size ANALYSETTE 22 NANOTEC (FRITSCH). Size of particles D50 was 1.1 micrometers (i.e., size of 50% of particles did not exceed 1.1 micrometers).

Softening temperature for the obtained product determined by “ring and ball” method was 84°C.

In addition, this sample was studied by IR spectroscopy (see the spectrum in Fig. 1 ). The data shows that the spectrum had reflexes at 1540 cm ^-1 and 1580 cm ^-1 corresponding to stearic acid (oscillations of COOH group) and stearates of metals (oscillations of COOMe group). Comparison of peak areas indicates that ratio of stearates and stearic acid in the system was 10 : 90. Example 4

A mineral named basalt that had the following chemical composition: mainly 45-52% of SiO ₂ , 15-18% of AI2O3, 8-15% of Fe ₃ O4, 6-12% of CaO, 5-7% of MgO and grinded to particles of size not exceeding 3 millimeters and zinc oxide amounting to 30.5 grams and 2.6 grams, correspondingly, as well as stearic acid amounting to 18.9 grams were carefully mixed and loaded into a grinding cylinder having volume of 250 cm ³ of Aktivator planetary mill with water cooling (Novosibirsk). The following grinding mode was used: planetary disk rate of 700 s ^-1 , grinding time of 20 minutes, use of 160 balls having diameter of 10 millimeters.

The obtained product was studied using laser analyzer of particle size ANALYSETTE 22 NANOTEC (FRITSCH). Size of particles D50 was 1.2 micrometers (i.e., size of 50% of particles did not exceed 1 .2 micrometers). Softening temperature for the obtained product determined by “ring and ball” method was 103°C.

Example 5

The processing additives obtained under conditions similar to Examples 1 to 4 were introduced into rubber compounds. Test results for the obtained rubber compounds related to plastoelastic and viscoelastic properties thereof are presented in Table 1 .

A processing additive known under trade name “Aktiplast” (manufactured by Rhein Chemie) was used as a reference.

Table 1

The presented data shows that introduction of the reference sample of processing additive and the experimental samples caused noticeable decrease in Mooney viscosity (by approximately 7%), which proves enough effectiveness of the experimental samples. Safety level of treatment of compounds with additives described in Examples 1 to 4 was somewhat higher, particularly with additive described in Example 2, which is proved by prevulcanization resistance parameters Ts and T35 at 103°C.

Evaluation of viscoelastic properties of rubber compounds shows advantage of the additive described in Example 1. When it was used, value of elasticity modulus G’ at 1 % deformation and value of Payne effect that characterizes distribution of filler in polymer matrix were improved by 4% and 7%, correspondingly, compared to the reference sample. Parameter tgb at 60°C and 10% deformation, which is correlated with heat generation in rubber under dynamic load, for compounds with additives obtained in Examples 1 to 4 was equal to that of the reference sample.

Test results for the obtained rubber compounds related to vulcanization kinetics of rubber compounds are presented in Table 2.

Table 2

Minimum torque that characterizes viscosity level of rubber compounds under particular test conditions (temperature of 155°C and corresponding shear stress) was equal for all additives. Maximum torque and parameter (MH - ML) of all additives obtained under conditions similar to described in Examples 1 to 4 were equal to that of the reference sample, except for higher level for the rubber compounds with additives obtained in Examples 1 and 3. The rubber compounds with additives of Examples 2 had 9% less vulcanization rate in comparison with the reference sample.

Test results for rubbers based on the above-mentioned rubber compounds, related to physical and mechanical tests are presented in Table 3.

Table 3

Main parameters related to stress-strain properties, namely, modulus at 100% elongation that characterizes density of vulcanization network, modulus at 300% elongation that additionally characterizes rubber-carbon interaction, tensile strength, relative elongation and tear strength were equal for rubbers with reference and experimental additives. Wear resistance of rubbers with processing additives of Examples 1 and 2 was higher by 3% and 6%, correspondingly, than that of rubbers with the reference additive. Multiple flexing crack growth resistance of rubbers with additives of Examples 1 , 3 and 4 was equal to that of the reference. Rubber with additive of Example 2 showed substantially lower crack growth resistance.

Test results for rubbers based on the above-mentioned rubber compounds related to elastic-hysteresis properties are presented in Table 4.

Table 4

The obtained data shows that rubbers with additives described in Examples 1 to 4 were technically equivalent to rubber with reference additive in relation to traction with icy road surface (tgb at -20°C) and to hysteresis loss (tgb at +60°C) that characterizes heat generation in rubbers or tire rolling loss. Wet road traction level evaluated by loss angle tangent at 0°C of rubber with additive of Example 1 was technically equivalent to that of the reference, while rubber with additive of Example 2 substantially (by 13- 15%) outperformed the reference.

INDUSTRIAL APPLICABILITY

The invention is applicable in production of automotive tires and other rubber goods items.