ADDITIVE FOR RUBBER COMPOUNDS AND METHOD FOR PRODUCING SAME

Abstract

The invention relates to additives for enhancing the electrical conductivity and physical and mechanical properties of rubber compounds, including, inter alia, the elastic modulus, tensile strength, tear resistance and abrasion resistance of composite elastomer-based materials (rubbers), and to composite elastomer-based materials (rubbers). The invention proposes an additive containing from 1 to 20 wt % carbon nanotubes, from 3 to 90 wt % high-viscosity organic rubber, and from 8 to 95 wt % low-molecular-weight organic dispersion medium. The present invention also proposes a method for producing the additive.

Claims

1. An additive to rubber compounds for enhancing electrical conductivity and physical and mechanical properties of rubber, the additive comprising: 1 to 20 wt % carbon nanotubes; 3 to 90 wt % high-viscosity organic rubber; and 8 to 95 wt % low-molecular-weight organic dispersion medium capable of dissolving the high-viscosity organic rubber (R) and selected from the group consisting of (a) oil with flash point of more than 200 C. and kinematic viscosity of less than 1 St at 100 C., (b) a polar solvent with relative dielectric permittivity of more than 5 at 25 C., and (c) an ester or a mixture of more than one esters of aliphatic alcohols with acids selected from the group consisting of (1) phthalic acid, (2) terephthalic acid, (3) sebacic acid, (4) adipic acid, and (5) cyclohexanedicarboxylic acid.

2. The additive of claim 1, wherein the high-viscosity organic rubber is selected from the group consisting of: natural rubber, synthetic isoprene rubbers, styrene butadiene rubber, nitrile butadiene rubber, hydrogenated nitrile butadiene rubber, butadiene rubber or butyl rubber, halobutyl rubber, ethylene propylene rubber, ethylene propylene diene rubber containing ethylene norbornene or dicyclopentadiene as the third monomer, propylene oxide rubber, acrylate rubber, carboxylate rubber, chloroprene rubber, fluoroelastomer, and a mixture of two or more of these rubbers.

3. The additive of claim 1, wherein the high-viscosity organic rubber has a viscosity ML.sub.(1+4) of more than 20 Mooney units at 100 C.

4. The additive of claim 3, wherein the high-viscosity organic rubber has a viscosity ML.sub.(1+4) of more than 40 Mooney units at 100 C.

5. The additive of claim 4, wherein the high-viscosity organic rubber has a viscosity ML.sub.(1+4) of more than 60 Mooney units at 100 C.

6. The additive of claim 1, wherein the dispersion medium is a polar solvent with a relative dielectric permittivity of more than 40 at 25 C.

7. The additive of claim 6, wherein the dispersion medium comprises at least 10 wt % propylene carbonate.

8. The additive of claim 6, wherein the dispersion medium comprises at least 10 wt % 1,2-butylene carbonate, or 2,3-butylene carbonate, or a mixture thereof.

9. The additive of claim 1, wherein more than 25 wt % carbon nanotubes are single-walled or double-walled carbon nanotubes.

10. The additive of claim 1, wherein the carbon nanotubes have a ratio of intensities of the G/D bands of more than 10 in Raman spectrum at 532 nm.

11. The additive of claim 10, wherein the carbon nanotubes have a ratio of intensities of the G/D bands of more than 40 in Raman spectrum at 532 nm.

12. The additive of claim 10, wherein the carbon nanotubes have a ratio of intensities of the G/D bands of more than 60 in Raman spectrum at 532 nm.

13. The additive of claim 1, wherein a ratio of a mass fraction of the carbon nanotubes to a mass fraction of rubber bound to the carbon nanotubes is less than 4.

14. The additive of claim 1, wherein at least some of the carbon nanotubes are bundled.

15. The additive of claim 14, wherein a thickness of at least a part of the carbon nanotube bundles is more than 300 nm.

16. The additive of claim 1, further comprising particles of one or more metals from groups 8-11 or their alloys.

17. The additive of claim 1, wherein the additive has a volume resistivity of not more than 2 Ohm.Math.m at a temperature of 25 C.

18. The additive of claim 1, wherein the additive has a viscosity of more than 5 and less than 90 Mooney units at a temperature of 100 C.

19. The additive of claim 1, wherein a viscosity of the additive is characterized by a needle penetration depth of less than 15 mm at a temperature of 25 C. over 5 s at a defined load of 100 g.

20. A method for producing the additive according to claim 1, wherein the method comprises the following sequential stages: (1) dissolving the high-viscosity rubber (R) in the dispersion medium, and (II) dispersing carbon nanotubes in the solution of stage (I).

21. The method of claim 20, further comprising an additional stage of preliminary wetting and mixing of carbon nanotubes in the dispersion medium or one of the components of the dispersion medium, or in the solution of rubber (R) in the dispersion medium, between stages (I) and (II).

22. The method of claim 21, wherein, after stage (II), the method further comprises stage (III) of mixing a resultant slurry of carbon nanotubes, a dispersion medium, and a high-viscosity organic rubber (R), with a high-viscosity organic rubber (R2), and wherein a ratio of a weight of rubber (R2) to a weight of the slurry after stage (II) is less than or equal to 5.

23. A method for producing rubber, wherein the method comprises adding an additive according to claim 1 to the rubber.

24. The method of claim 23, wherein the adding further comprises adding a filler, and/or a plasticizer, and/or an antioxidant, and/or a silane coupling agent, and/or a curing agent, and/or a cure accelerator, and/or a cure retarder, and/or a stabilizer, and/or a dye, and/or a pigment into the rubber.

25. The method of claim 23, wherein the adding is performed using an internal mixer.

26. The method of claim 23, wherein the adding is performed using two roll rubber mill.

27. A rubber with enhanced electrical conductivity and physical and mechanical properties, the rubber comprising 0.01 to 1 wt % carbon nanotubes and wherein the rubber is produced by the method of claim 23.

Description

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0077] Reference will now be made in detail to the preferred embodiments of the present invention

EXAMPLES

[0078] In the Examples and Tables given below, the numerical values of physical and chemical properties were determined experimentally according to the methods described in the following standards: Russian GOST R 54552-2011 Rubbers and Rubber Compounds. Standard Test Methods for Viscosity, Stress Relaxation, and Pre-Vulcanization Characteristics by Mooney Viscometer (also ASTM D 1646-2015); Russian GOST R 54547-2011. Rubber Compounds. Standard Test Method for Property-Vulcanization Using Rotorless Cure Meters (also ASTM D 5289-2012); Russian GOST R 54553-2011 Vulcanized Rubber and Thermoplastic Elastomers. Standard Test Method for Tensile Stress-Strain Properties (also ASTM D 412); Russian GOST 262-79. Rubber. Standard Test Method of Tear Strength (also ASTM D 624); Russian GOST R ISO 7619-1-2009 Rubber, Vulcanized or Thermoplastic. Determination of Indentation Hardness. Part 1. Durometer Method (Shore Hardness) (also ISO 7619-1:2004); ASTM D 991Standard Test Method for Rubber PropertyVolume Resistivity Of Electrically Conductive and Antistatic Products; Russian GOST-11501-78 Petroleum Bitumens. Standard Test Method for Determination of Depth of Needle Penetration (also DIN EN1426:2015, ASTM D 5).

[0079] The following symbols and abbreviations are used in the Tables below: NPDneedle penetration depth (according to Russian GOST-11501-78), expressed in penetration units equal to 0.1 mm, .sub.vvolume resistivity, .sub.ssurface resistivity, M50stress at a given elongation 50%, M100stress at a given elongation 100%, M200stress at a given elongation 200%, M300stress at a given elongation 300%, TSmaximum tear stress, EBmaximum elongation at break, CrTearcrescent-shaped sample tear resistance, AnTearangle-shaped sample tear resistance, Hhardness, thermal conductivity.

Examples 1-34

[0080] Examples 1-4 illustrate comparative examples according to the prototype, i.e., additives comprising single-walled carbon nanotubes and a dispersion medium that is a low-molecular-weight solvent with average molecular weight of less than 1000 Dalton (aromatic oil TDAE Norman 346: hydrogenated extract of aromatic hydrocarbons of petrol origin with viscosity of about 0.02 Pas at 100 C., flash point 220 C.) or a liquid rubber oligomer (butadiene Kuraray LBR-352 with MW=9000 Da: liquid with viscosity of 6 Pas at 38 C., nitrile butadiene Nipol 1312 (Zeon Chemicals): liquid with viscosity of 20-30 Pas, or styrene butadiene with MW=8500 g/molKuraray LSBR-820: liquid with viscosity of 350 Pas at 38 C.). The compositions of these additives, the properties of TUBALL single-walled carbon nanotubes (SWCNT) used for their production, as well as the properties of the dispersion medium (or liquid rubber oligomer) are given in Table 1.

[0081] Examples 5-34 illustrate the Additives of the present invention for enhancing electrical conductivity and physical and mechanical properties of rubber comprising carbon nanotubes, wherein the additives comprise 1 to 20 wt % carbon nanotubes, 3 to 90% high-viscosity organic rubber (R), and 8 to 95 wt % low-molecular-weight organic dispersion medium capable of dissolving the high-viscosity organic rubber (R). In each of the provided Examples, the additive comprises TUBALL single-walled carbon nanotubes with an average diameter (d) of more than 1.4 and less than 1.8 nm, specific surface area (S) of more than 300 and less than 600 m.sup.2/g, and the ratio of intensities of the G/D bands in Raman spectrum of more than 40 at 532 nm. TUBALL single-walled carbon nanotubes contain iron impurities in the form of nanoparticles of iron, iron carbide, and a small amount of iron oxides.

[0082] The content of iron impurities in TUBALL (m.sub.Fe) is less than 15 wt %. Exceptions are Examples 15 and 24, which use TUBALL single-walled carbon nanotubes subjected to additional purification from iron impurities down to the content of 0.65 wt %. These single-walled carbon nanotubes are characterized by a larger specific surface area of 1230 m.sup.2/g, which is due to opening internal channels in carbon nanotubes in the course of purification. The actual values of parameters of TUBALL single-walled carbon nanotubes in the additives are given in Table 1. In each of the provided Examples, the additive comprises a low-molecular-weight dispersion medium and a high-viscosity organic rubber. The chemical composition, viscosity (), and flash point of the dispersion medium (t.sub.fl) are given in Table 1. The Table uses the following abbreviations: TDAEtreated distillate aromatic extract, an aromatic oil produced by hydrogenation of petrol distillates, Norman 346 oil was used (JSC Orgkhim), P460paraffin oil type Petronas Process Oil P 460 (Petronas), DBPdibutyl phthalate, PCpropylene carbonate, BCbutylene carbonate, DOAdioctyl adipate, DOSdioctyl sebacate, DINPdiisononyl phthalate.

[0083] The chemical composition, trademark, and viscosity of the high-viscosity organic rubber used in each additive (ML.sub.(1+4)) expressed in Mooney units, are given in Table 1. The Table uses the following abbreviations: NRnatural rubber, NBRnitrile butadiene rubber, EPDMethylene propylene diene monomer rubber. Table 1 also gives the wt % ratio of the weight of TUBALL to the weight of the additive (m.sub.CNT), the wt % ratio of the weight of high-viscosity organic rubber (R) to the weight of rubber (R) solution in dispersion medium (m.sub.R), and the ratio of the weight of SWCNT to the weight of rubber bound to them as determined by extraction in a solvent (m.sub.CNT/BdR).

[0084] The additives of Examples 5-34 were produced by sequentially performing stage (I) of dissolving the high-viscosity organic rubber (R) in the dispersion medium and stage (II) of subsequently dispersing single-walled carbon nanotubes in the solution of stage (I). To prevent dust formation in the working area during dispersion, single-walled carbon nanotubes were preliminary wetted between stages (I) and (II): by a dispersion medium (oil P460) in Examples 5-14, and by a rubber solution in the dispersion medium in Examples 15-34.

[0085] The dispersion medium in the additives of Examples 5-16 comprises mineral petrol oils with a flash point of more than 200 C. and a viscosity of less than 1 St at 100 C. (21 cSt for TDAE Normal 346 and 36 cSt for Petronas P460). The dispersion medium in the additives of Examples 18-31 comprises nitrile butadiene rubber and a polar solvent with relative dielectric permittivity of more than 5 at 25 C. (DBP: 6.4; butylene carbonate: 56; propylene carbonate: 64). In Example 30, the dispersion medium is solution 1 of propylene carbonate and butylene carbonate with a 9:1 weight ratio (isomeric composition of the butylene carbonate is not known). In Example 31, the dispersion medium is solution 2 of propylene carbonate and butylene carbonate (isomeric composition of the butylene carbonate is not known) with a 1:9 weight ratio. The dispersion medium in the additives of Examples 32-34 comprises a polar solvent with a lower relative dielectric permittivity (DOS: 4.0; DINP: 4.6).

[0086] Table 2 gives data on viscosity and electrical conductivity at a temperature of 25 C. of the additives of Examples 1-34.

Examples 35-41

[0087] The additives of Examples 35-38 were produced similar to the additive of Example 9, and the additives of Examples 39-41 were produced similarly to Example 26, but with different carbon nanotubes with the properties given in Table 3. Examples 35 and 39 use carbon nanotubes comprising mostly double-walled carbon nanotubes, which is confirmed by high resolution transmission electron microscopy, the mass fraction of single-walled carbon nanotubes is about 30 wt %. Examples 36, 37 and 40 used multi-walled carbon nanotubes, but, in Example 37, they were preliminary mixed with TUBALL single-walled carbon nanotubes in a weight ratio of 3:1. Examples 38 and 41 used the so-called few-walled carbon nanotubes, i.e., multi-walled carbon nanotubes with the number of graphene layers in the wall between 2 and 5, the carbon nanotubes mostly comprised 3 to 4 graphene layers.

Examples 42-45

[0088] The additives were produced similar to the additives of Examples 9, 17 and 26, but, after stage (II), a further stage of mixing the obtained slurry, comprising carbon nanotubes, a dispersion medium, and a high-viscosity organic rubber (R), with a high-viscosity organic rubber (R2) was performed, with the ratio of the weight of rubber (R2) to the weight of the slurry after stage (II) of less than or equal to 5. The composition and type of the rubber (R2) used, the weight ratio of the weight of rubber (R2) to the weight of the slurry after stage (II), as well as the final composition of the additive and the weight ratio of carbon nanotubes to the bound rubber are given in Table 4.

Example 46

[0089] This Example illustrates producing rubber mixtures and rubbers based on EPDM rubber without carbon black using the additives of Examples 5-14. The additive of Comparative Example 2 is used for comparison with the prototype. The rubber was mixed in two stages using an internal mixer WSM SKI3.5 L and post-mixing homogenization on two roll rubber mills 200/400 with a diameter of 200 mm, a length of 400 mm, and a friction coefficient of 1:1.2. At the first stage, rubber, oil P460, PEG 4000, CaCO.sub.3, white carbon (SiO.sub.2), kaolin, TiO.sub.2, and ZnO are mixed for 5 minutes at the maximum mixture temperature of 150 C. At the second stage, the curing agents of triallylisocyanurate (TAIC) and bis(tert-butylperoxyisopropyl)benzene (BIPB40GR), as well as the additive comprising carbon nanotubes, were introduced into the rubber compound over 2 minutes at the maximum mixture temperature of 90 C. Rubber mixing comprises a stage of adding an additive comprising carbon nanotubes into the rubber compound, wherein adding of this additive into the rubber compound is combined with adding curing agents to the rubber compound.

[0090] The formulation of the rubber mixtures and the results of testing cured rubber samples for electrical conductivity and physical and mechanical properties are given in Tables 5 and 6. These data show that the additives of Examples 5-14 provide the technical result, i.e., significantly enhanced electrical conductivity and mechanical properties (moduli M50-M200 and tear resistance), while the effect of the additive of Comparative Example 2 on electrical conductivity and tear resistance is much lower, and it is actually negative on M50-M200.

[0091] The effect of the amount of additive introduced is illustrated by Table 7 which gives data for varying amounts of the additive of Example 9. Varying the concentration of carbon nanotubes in rubber from 0.04 to 1% achieves the technical result: significantly enhanced electrical conductivity and mechanical properties (moduli M50-M200 and tear resistance), some rubber samples also show significantly increased tensile strength and maximum elongation at break.

Example 47

[0092] This Example illustrates producing rubber mixtures and rubbers based on EPDM rubber without carbon black using the additives of Examples 35-38. The additive of Comparative Example 2 is used for comparison with the prototype. The rubber was mixed similarly to Example 48, in two stages using an internal mixer WSM SKI3.5 L and post-mixing homogenization on two roll rubber mills Zamak LM 200/400 with a diameter of 200 mm, a length of 400 mm, and a friction coefficient of 1:1.2.

[0093] The formulation of the rubber mixtures and the results of testing cured rubber samples for electrical conductivity and physical and mechanical properties are given in Table 8. These data show that the additives of Examples 35-38 provide the technical result, i.e., enhanced electrical conductivity and mechanical properties (moduli M50-M200 and tear resistance), however, the largest effect is achieved when using single-walled and/or double-walled carbon nanotubes (the additives of Examples 9 and 35). Thus, additives comprising single-walled and/or double-walled carbon nanotubes are preferable.

Example 48

[0094] This Example illustrates producing rubber mixtures and rubbers based on EPDM rubber with carbon black N550, an electrically conductive filler, or electrically conductive carbon powder Vulcan XC-72, using the additive of Example 9. The additive of Comparative Example 2 is used for comparison with the prototype. The rubber was mixed in two stages: the first stage used an internal mixer WSM SKI3.5 L, the second stage was performed on two roll rubber mills Zamak 200/400 with a diameter of 200 mm, a length of 400 mm, and a friction coefficient of 1:1.2, over 2 minutes at the maximum temperature of 90 C. The additive comprising carbon nanotubes was introduced on two roll rubber mills, combining the adding of this additive into the rubber compound with the adding of curing agents (2-mercaptobenzothiazole (MBT), tetramethylthiuram disulfide (TMTD), and sulfur) into the rubber compound.

[0095] The formulation of the rubber mixtures and the results of testing cured rubber samples for electrical conductivity and physical and mechanical properties are given in Table 9. These data show that the additive of Example 9 provides the technical result, i.e., significantly enhanced mechanical properties (moduli M50-M200 and tear resistance), as well as a very significant increase in electrical conductivity, even despite the fact that the rubber was already electrically conductive without the additive. At the same time, the effect of the additive of Comparative Example 2 on physical and mechanical properties is significantly lower and is within the measurement uncertainty, while the electrical conductivity of the rubber with this additive actually decreases.

Example 49

[0096] This example illustrates that an additional technical result can be achieved using the additive of this invention, i.e., producing colored (non-black) electrically conductive rubber mixtures and rubbers based on EPDM rubber. Rubber formulation is given in Table 10. An organic dye, phthalocyanine blue pigment, was added to the rubber mixture for coloring. Titanium dioxide content was increased to whiten the rubber. This Example also illustrates the possibility of adding carbon nanotubes into the rubber mixture as part of an additive comprising a high concentration of the high-viscosity organic rubber according to Example 42. The base rubber without the additive was mixed in two stages: at the first stage, which was performed using an internal mixer WSM SKI3.5 L, all components, except the curing system (TAIC and peroxide), were added to the rubber; the second stage, which comprises adding the curing agents, was performed using two roll rubber mills Zamak 200/400 with a diameter of 200 mm, a length of 400 mm, and a friction coefficient of 1:1.2, over 2 minutes at the maximum temperature of 90 C. The additive comprising carbon nanotubes was introduced into the rubber using an internal mixer before adding other components of the rubber mixture into it. The resultant rubber has a rich blue color along with electrical conductivity properties sufficient to dissipate static charge. The data of Table 10 demonstrate that adding the additive of both Example 9 and Example 42 resulted in enhanced physical and mechanical properties of the rubber.

Example 50

[0097] This Example illustrates producing rubber compounds and rubbers based on a mixture of rubbers, i.e., natural rubber (SMR10 rubber was used) and butadiene rubber (BR-22 rubber was used), using the additive of any of Examples 9, 15-17 and 43-44. The additive of Comparative Example 1 is used for comparison with the prototype. The composition of rubber mixtures is given in Table 11. This composition emulates the composition of rubber mixtures in treads of agricultural and truck tires. The rubber without the additive was mixed in two stages using an internal mixer WSM SKI3.5 L and post-mixing homogenization on two roll rubber mills Zamak 200/400 with a friction coefficient of 1:1.2. At the first stage, the rubbers, oil Nytex 4700, carbon black N234, stearic acid, ZnO, and N-(1,3-dimethyl)-N-phenyl-1,4-phenyldiamine (6PPD) antioxidant were mixed for 5 minutes at the maximum mixture temperature of 130 C. At the second stage, the curing agents of 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ); N-cyclohexyl-2-benzothiazole sulfenamide (Sulceneamide C) (CBS); diphenyl guanidine (DPG), pre-vulcanization inhibitor (PVI), and sulfur were introduced into the rubber compound over 2 minutes at the maximum mixture temperature of 100 C. The stage of adding the additive comprising carbon nanotubes was performed using two roll rubber mills Zamak 200/400 with a friction coefficient of 1:1.2, between the first and second stages of mixing the base rubber mixture. The volume resistivity of rubber samples after curing and its physical and mechanical properties are given in Table 11, pre-cut crescent-shaped samples were used for testing tear resistance. These data show that adding the additives of Examples 15-17, 43, 9 and 42 into the rubber compound significantly decreases rubber volume resistivity, increases the values of stress at a given elongation of 100-300%, tensile strength, and tear resistance, while not having a detrimental effect on the maximum elongation at break. At the same time, adding of the additive of Comparative Example 1 given herein for comparison with the Prototype does not result in any significant improvement of rubber properties.

Example 51

[0098] This Example illustrates producing rubber mixtures and rubbers based on a mixture of rubbers, i.e., natural rubber (SVR-3 L rubber was used) and butadiene rubber (Buna CB 24 rubber was used), without a plasticizer oil using the additive of any of Examples 16, 17 and 25. The additive of Comparative Example 1 is used for comparison with the prototype. The composition of rubber mixtures is given in Table 12. The rubber without the additive was mixed in two stages using an internal mixer WSM SKI3.5 L and post-mixing homogenization on two roll rubber mills Zamak 200/400 with a friction coefficient of 1:1.2. At the first stage, the rubbers, carbon black N330, stearic acid, ZnO, and N-(isopropyl)-N-phenyl-1,4-phenyldiamine (iPPD) antioxidant were mixed for 5 minutes at the maximum mixture temperature 130 C. At the second stage, the curing agents of benzothiazole sulfenamide (CBS); diphenyl guanidine (DPG), and sulfur, as well as the additive were introduced into the rubber compound over 2 minutes at the maximum temperature of 100 C. The stage of adding the additive comprising carbon nanotubes is thus combined with the stage of adding the curing system.

[0099] The volume resistivity of rubber samples after curing and its physical and mechanical properties are given in Table 12, pre-cut crescent-shaped samples were used for testing tear resistance. Adding the additives of Examples 16, 17, and 25 into the rubber compound significantly decreases rubber volume resistivity, increases the values of stress at a given elongation of 100-300%, as well as tear resistance, while not having a significant detrimental effect on the maximum elongation at break and tensile strength. Adding the additives of Examples 16, 17, and 25 into the rubber compound also increases rubber hardness. At the same time, adding of the additive of Comparative Example 1 given herein for comparison with the Prototype does not result in any significant improvement of rubber properties.

Example 52

[0100] This Example illustrates producing rubber mixtures and rubbers based on nitrile butadiene rubber filled with carbon black using the additive of Examples 18-20, 25-26, and 44. To compare with the prototype, the additive of Comparative Example 3 was used (dispersion of single-walled carbon nanotubes in liquid nitrile butyl rubber oligomer Nipol 1213). The rubber was mixed in two stages using an internal mixer WSM SKI3.5 L and post-mixing homogenization on two roll rubber mills 200/400 with a diameter of 200 mm, a length of 400 mm, and a friction coefficient of 1:1.2. At the first stage, the rubber, carbon black, ZnO, stearic acid, dibutyl phthalate (DBP), and N-(isopropyl)-N-phenyl-1,4-phenyldiamine (iPPD) antioxidant were mixed for 5 minutes at the maximum mixture temperature of 120 C. At the second stage, the curing agents of N-cyclohexyl-2-benzothiazole sulfenamide (CZ) and sulfur, over 2 minutes at the maximum mixture temperature of 90 C. The stage of adding the additive comprising carbon nanotubes was performed using an internal mixer, wherein adding this additive into the rubber compound is combined with adding curing agents into the rubber compound.

[0101] The formulation of the rubber mixtures and the results of testing cured rubber samples for electrical conductivity and physical and mechanical properties are given in Table 13. These data show that the additives of Examples 18-20, 25-26, and 46 provide the technical result, i.e., enhanced mechanical properties (moduli M50-M200 and tear resistance), as well as enhanced electrical conductivity, while the effect of the additive of Comparative Example 3 on the electrical conductivity is significantly lower, and there is no effect on physical and mechanical properties.

Example 53

[0102] This Example illustrates producing rubber mixtures and rubbers based on nitrile butadiene rubber filled with silicon dioxide using the additive of Examples 21-23, 25, 29, 31-34, and 39-41. To compare with the prototype, the additive of Comparative Example 3 was used (dispersion of single-walled carbon nanotubes in liquid nitrile butyl rubber oligomer Nipol 1213). The rubber was mixed in two stages using an internal mixer WSM SKI3.5 L and post-mixing homogenization on two roll rubber mills 200/400 with a diameter of 200 mm, a length of 400 mm, and a friction coefficient of 1:1.2.

[0103] At the first stage, the rubber, carbon black, ZnO, stearic acid, silicon dioxide, silane coupling agent TESPT (Si-69), titanium dioxide and N-(isopropyl)-N-phenyl-1,4-phenyldiamine (iPPD) antioxidant were mixed for 5 minutes at the maximum mixture temperature of 150 C. At the second stage, the curing agents of mercaptobenzothiazole disulfide (MBTS), tetramethylthiuram disulfide (TMTD), and sulfur were introduced into the rubber compound over 2 minutes at the maximum temperature of 90 C. The stage of adding the additive comprising carbon nanotubes was performed using an internal mixer, wherein adding this additive into the rubber compound is combined with adding curing agents into the rubber compound.

[0104] The formulation of the rubber mixtures and the results of testing cured rubber samples for electrical conductivity and physical and mechanical properties are given in Tables 14 and 15. These data show that the additives of Examples 21-23, 25, 29, 31-34, and 39-41 provide the technical result, i.e., enhanced mechanical properties (moduli M50-M200 and tear resistance) and electrical conductivity of rubber sufficient to dissipate static charge, although achieving the technical result requires a larger amount of Additives 40-41 (comprising multi-walled carbon nanotubes), while the effect of the additive of Comparative Example 3 on electrical conductivity and tear resistance is insignificant.

Example 54

[0105] This Example illustrates producing rubber mixtures and rubbers based on a mixture of rubbers, i.e., styrene butadiene rubber (solution SBR Buna VSL 4526-2HM expanded with TDAE oil) and butadiene rubber (Buna CB 24 rubber was used), using the additive of any of Examples 9, 22, 24-28, and 45. To compare with the prototype, the additive of Comparative Example 4 was used, in which single-walled carbon nanotubes were dispersed in liquid oligomer of styrene butadiene rubber Kuraray LSBR-820. The composition of rubber mixtures is given in Tables 16 and 17. This composition emulates the composition of the rubber mixtures for treads of car tires. It should be noted that the rubber mixtures do not comprise carbon black or any other electrically conductive fillers apart from the Additive comprising carbon nanotubes. The rubber without the Additive was mixed in three stages using an internal mixer WSM SKI3.5 L and post-mixing homogenization on two roll rubber mills Zamak 200/400 with a friction coefficient of 1:1.2.

[0106] At the first stage, the rubbers, oil TDAE Normal 346, silicon dioxide, silane coupling agent bis(triethoxysilylpropyl)tetrasulfide (Si-69), and stearic acid were mixed for 5 minutes at the maximum mixture temperature of 150 C. The amount of the plasticizer (TDAE oil) was reduced by the amount of low-molecular-weight dispersion medium introduced with the Additive. At the second stage, mixture homogenization was performed, and zinc oxide and N-(1,3-dimethyl)-N-phenyl-1,4-phenyldiamine (iPPD) antioxidant were added over 2 minutes at the maximum mixture temperature of 110 C. At the third stage, the curing agents of sulfur, N-tert-butyl-2-benzothiazole sulfenamide (TBBS) and diphenyl guanidine (DPG) were introduced into the rubber compound over 2 minutes at the maximum mixture temperature of 110 C. The additive was introduced at the second stage, while combining the stage of adding the Additive with mixture homogenization and addition of zinc oxide and antioxidant. An exception is addition of the Additive of Example 45 into styrene butadiene rubber at a separate stage on two roll rubber mills prior to stage 1. The volume resistivity of rubber samples after curing and its physical and mechanical properties are given in Tables 16 and 17, pre-cut crescent-shaped samples were used for testing tear resistance.

[0107] This data shows that adding the Additives of Examples 9, 22, 24-28, and 45 into the rubber compound significantly decreases volume resistivity and surface resistance of rubber, while providing an electrically conductive rubber even in the absence of any other electrically conductive fillers, increases the values of stress at a given elongation of 100-300% and tensile strength, as well as tear resistance, while not having a detrimental effect on the maximum elongation at break. At the same time, adding of the additive of Comparative Example 4 given herein for comparison with the Prototype does not result in any significant improvement of rubber properties.

[0108] As Table 17 demonstrates, adding the additive of Examples 24-25 and 45 significantly increases loss tangent in dynamical mechanical tests (tan(S)) at 0 C., which characterizes the friction coefficient and traction of tire tread. Thus, adding the additive in the rubber mixture for production of tire tread can significantly improve tire quality. It should be noted that this addition of the additive has only a very insignificant effect on (tan(6)) at elevated temperatures (such as at 60 C.), i.e., it does not increase rolling resistance of the tire.

[0109] It should also be noted that this Example further illustrates achieving an additional technical effect, i.e., increased thermal conductivity of the cured rubber by 10% upon adding 0.38 wt % carbon nanotubes. Thermal conductivity data is given in Table 17.

TABLE-US-00001 TABLE 1 m.sub.CNT, d.sub.CNT, S.sub.CNT, m.sub.Fe, Dispers. t.sub.fl, High-viscosity m.sub.R, ML.sub.(1+4), m.sub.CNT/ Example wt % nm m.sup.2/g G/D wt % medium , Pa .Math. s C. rubber, R wt % MU m.sub.BdR 1 (comp) 10 1.6 480 60 14.1 TDAE 0.02 220 None oil (100 C.) 2 (comp) 5 1.6 480 60 14.1 LBR-352 6 None >100 (38 C.) 3 (comp) 5 1.6 480 60 14.1 Nipol- 22 None >100 1312 (25 C.) 4 (comp) 10 1.6 480 60 14.1 L-SBR- 350 None >100 820 (38 C.) 5 10 1.6 480 60 14.1 P460 oil 0.03 270 EPDM 10 46 2.1 (100 C.) Keltan 4450 (125 C.) 6 10 1.6 480 60 14.1 P460 oil 0.03 270 EPDM 10 25 1.9 (100 C.) Keltan 2650 (125 C.) 7 10 1.6 480 60 14.1 P460 oil 0.03 270 EPDM 10 60 1.6 (100 C.) Vistalon7001 (125 C.) 8 10 1.6 480 60 14.1 P460 oil 0.03 270 EPDM 10 25 2 (100 C.) Vistalon2502 (125 C.) 9 5 1.54 520 72 12.2 P460 oil 0.03 270 EPDM 10 25 1.2 (100 C.) Vistalon2502 (125 C.) 10 5 1.54 520 72 12.2 P460 oil 0.03 270 EPDM 4 25 2.6 (100 C.) Vistalon2502 (125 C.) 11 5 1.54 520 72 12.2 P460 oil 0.03 270 EPDM 7 25 1.9 (100 C.) Vistalon2502 (125 C.) 12 5 1.54 520 72 12.2 P460 oil 0.03 270 EPDM 15 25 1.1 (100 C.) Vistalon2502 (125 C.) 13 5 1.54 520 72 12.2 P460 oil 0.03 270 EPDM 20 25 0.95 (100 C.) Vistalon2502 (125 C.) 14 5 1.54 520 72 12.2 P460 oil 0.03 270 EPDM 40 25 0.89 (100 C.) Vistalon2502 (125 C.) 15 1 1.59 1230 71 0.64 TDAE 0.02 220 NR SVR 3L 10 75 0.4 oil (100 C.) (100 C.) 16 5 1.65 470 54 9.8 TDAE 0.02 220 NR SVR 3L 18 75 0.55 oil (100 C.) (100 C.) 17 10 1.65 470 54 9.8 TDAE 0.02 220 NR SVR 3L 25 75 0.62 oil (100 C.) (100 C.) 18 5 1.7 460 84 14.3 DBP 0.016 157 NBR 20 30 0.48 (25 C.) Perbunan2831 (100 C.) 19 5 1.7 460 84 14.3 DBP 0.016 157 NBR Krynac 20 30 0.52 (25 C.) 3330F (100 C.) 20 5 1.7 460 84 14.3 DBP 0.016 157 NBR 20 120 0.51 (25 C.) Krynac28120F (100 C.) 21 5 1.7 460 84 14.3 DBP 0.016 157 NBR 15 65 0.83 (25 C.) Perbunan 3965 (100 C.) 22 5 1.7 460 84 14.3 DBP 0.016 157 NBR 25 65 0.75 (25 C.) Perbunan 3965 (100 C.) 23 5 1.7 460 84 14.3 DBP 0.016 157 NBR 40 45 0.53 (25 C.) Perbunan 3945 (100 C.) 24 5 1.59 1230 71 0.64 PC 0.002 132 NBR 15 65 0.70 (25 C.) Perbunan 3965 (100 C.) 25 5 1.65 470 54 9.8 PC 0.002 132 NBR 23 65 0.6 (25 C.) Perbunan 3965 (100 C.) 26 10 1.65 470 54 9.8 PC 0.002 132 NBR 25 65 0.65 (25 C.) Perbunan 3965 (100 C.) 27 15 1.65 470 54 9.8 PC 0.002 132 NBR 25 65 0.76 (25 C.) Perbunan 3965 (100 C.) 28 20 1.65 470 54 9.8 PC 0.002 132 NBR 25 45 1.05 (25 C.) Perbunan 3945 (100 C.) 29 5 1.65 470 54 9.8 BC 0.002 130 NBR 25 65 0.73 (25 C.) Perbunan 3965 (100 C.) 30 5 1.65 470 54 9.8 Solution 0.002 130 NBR 25 65 0.71 1 (25 C.) Perbunan 3965 (100 C.) 31 5 1.65 470 54 9.8 Solution 0.002 130 NBR 25 65 0.75 2 (25 C.) Perbunan 3965 (100 C.) 32 5 1.7 460 84 14 DOA 0.015 194 NBR 18 65 3.6 (20 C.) Perbunan 3965 (100 C.) 33 5 1.7 460 84 14 DOS 0.02 215 NBR 18 65 3.4 (20 C.) Perbunan 3965 (100 C.) 34 5 1.7 460 84 14 DINP 0.08 200 NBR 18 65 2.9 (20 C.) Perbunan 3965 (100 C.)

TABLE-US-00002 TABLE 2 m.sub.CNT, Dispersion High-viscosity m.sub.R, ML.sub.(1+4) NPD, v, Example wt % medium rubber, R wt % 25 C., MU 0.1 mm Ohm .Math. m 1 (Comp.) 10 TDAE oil None 27 <20 0.05 2 (Comp.) 5 LBR-352 None 12 76 0.18 3 (Comp.) 5 Nipol-1312 None 14 63 0.15 4 (Comp.) 10 L-SBR-820 None 86 <20 0.25 5 10 P460 oil Keltan 4450 10 37 <20 0.015 6 10 P460 oil Keltan 2650 10 30 <20 0.06 7 10 P460 oil Vistalon 7001 10 40 <20 0.04 8 10 P460 oil Vistalon 2502 10 35 <20 0.04 9 5 P460 oil Vistalon 2502 10 14 57 0.7 10 5 P460 oil Vistalon 2502 4 10 105 0.4 11 5 P460 oil Vistalon 2502 7 15 51 0.7 12 5 P460 oil Vistalon 2502 15 21 <20 0.8 13 5 P460 oil Vistalon 2502 20 28 <20 0.8 14 5 P460 oil Vistalon 2502 40 30 <20 0.9 15 1 TDAE oil SVR 3L 10 5 166 890 16 5 TDAE oil SVR 3L 10 8 83 2.0 17 10 TDAE oil SVR 3L 25 32 <20 0.15 18 5 DBP Perbunan 2831F 20 12 90 4.2 19 5 DBP Krynac 3330F 20 10 102 6.1 20 5 DBP Krynac 28120F 20 25 <20 2.3 21 5 DBP Perbunan 3965 15 9 114 0.15 22 5 DBP Perbunan 3965 25 13 80 1.2 23 5 DBP Perbunan 3945 40 18 26 2.2 24 5 PC Perbunan 3965 15 8 125 0.7 25 5 PC Perbunan 3965 23 9 112 0.5 26 10 PC Perbunan 3965 25 34 <20 0.12 27 15 PC Perbunan 3965 25 55 <20 0.03 28 20 PC Perbunan 3965 25 71 <20 0.008 29 5 BC Perbunan 3965 25 12 89 0.8 30 5 Solution 1 Perbunan 3965 25 9 102 0.6 31 5 Solution 2 Perbunan 3965 25 10 98 0.4 32 5 DOA Perbunan 3965 20 14 59 1.8 33 5 DOS Perbunan 3965 20 16 40 1.4 34 5 DINP Perbunan 3965 20 13 73 1.9

TABLE-US-00003 TABLE 3 CNT in Example additive d, nm G/D S, m.sub.2/g Comment 35 and DWCNT and 1.3-3.2 46 420 SWCNT fraction 39 SWCNT about 30 wt % 36 and MWCNT 9-14 0.8 230 6-10 graphene 40 layers in MWCNT wall 37 MWCNT and 1.3-14 14 300 3:1 mixture SWCNT with TUBALL 38 and MWCNT 3-7 6.2 410 2-5 graphene 41 layers in MWCNT wall

TABLE-US-00004 TABLE 4 Rubber R2 Additive composition, wt % Slurry of Composition R2: Dispersion m.sub.CNT/ Example Example and type slurry medium R + R2 CNT m.sub.BdR 42 9 EPDM 4 15.6 83.4 1 0.95 43 17 NR SVR 3L 4 13.5 84.5 2 0.61 44 26 NBR Perbunan 5 11.2 87.1 1.67 0.65 3965 45 26 SBR Buna VSL 5 11.2 87.1 1.67 0.63 4526 2HM

TABLE-US-00005 TABLE 5 Comparative examples Invention examples Additive None 2 5 6 7 8 9 of Example Additive 0 6 3 3 3 3 6 concentration, wt % CNT concentration 0 0.3 0.3 0.3 0.3 0.3 0.3 in rubber, wt % Composition of rubber mixture, parts (w/w) EPDM rubber 100 100 100 100 100 100 100 Keltan 4450 Additive None 12.1 5.85 5.85 5.85 5.85 12.1 P460 oil 5.0 5.0 5.0 5.0 5.0 5.0 5.0 PEG 4000 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Chalk 10.0 10.0 10.0 10.0 10.0 10.0 10.0 White carbon 43.0 43.0 43.0 43.0 43.0 43.0 43.0 Kaolin 10.0 10.0 10.0 10.0 10.0 10.0 10.0 TiO.sub.2 5.0 5.0 5.0 5.0 5.0 5.0 5.0 ZnO 3.0 3.0 3.0 3.0 3.0 3.0 3.0 TAIC 8.0 8.0 8.0 8.0 8.0 8.0 8.0 BIPB-40-GR 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Test results for cured rubber .sub.V, Ohm .Math. m 1.0E+11 6.3E+06 7.8E+04 1.0E+03 3.3E+05 1.2E+03 2.7E+01 .sub.S, Ohm/ 1.0E+12 5.2E+10 4.6E+08 1.5E+07 2.8E+09 1.4E+07 3.4E+05 M50, MPa 2.7 1.8 2.6 3.2 2.9 3.2 3.4 M100, MPa 4.3 4 4.3 5.1 4.5 5.1 5.6 M200, MPa 7.8 7.4 7.7 8.2 8.0 8.4 8.9 TS, MPa 11.8 11.9 11.2 11.9 11.8 12.1 12.4 EB, % 290 183 265 310 296 314 324 AnTear, kN/m 13.2 15.3 20.1 21.3 19.4 19.4 25.8

TABLE-US-00006 TABLE 6 Comp. examples Invention examples Additive None 2 10 11 12 13 14 of Example Additive 0 6 6 6 6 6 6 concentration, wt % CNT concentration 0 0.3 0.3 0.3 0.3 0.3 0.3 in rubber, wt % Composition of rubber mixture, parts (w/w) EPDM rubber 100 100 100 100 100 100 100 Keltan 4450 Additive None 12.1 12.1 12.1 12.1 12.1 12.1 P460 oil 5.0 5.0 5.0 5.0 5.0 5.0 5.0 PEG 4000 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Chalk 10.0 10.0 10.0 10.0 10.0 10.0 10.0 White carbon 43.0 43.0 43.0 43.0 43.0 43.0 43.0 Kaolin 10.0 10.0 10.0 10.0 10.0 10.0 10.0 TiO.sub.2 5.0 5.0 5.0 5.0 5.0 5.0 5.0 ZnO 3.0 3.0 3.0 3.0 3.0 3.0 3.0 TAIC 8.0 8.0 8.0 8.0 8.0 8.0 8.0 BIPB-40-GR 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Test results for cured rubber .sub.V, Ohm .Math. m 1.0E+11 6.3E+06 4.7E+05 3.1E+04 2.5E+04 6.8E+04 1.3E+06 .sub.S, Ohm/ 1.0E+12 5.2E+10 3.5E+07 2.6E+06 9.4E+05 3.4E+07 8.6E+08 M50, MPa 2.7 1.8 2.8 3.2 3.3 3.3 2.9 M100, MPa 4.3 4.0 5.0 5.1 5.7 5.6 4.8 M200, MPa 7.8 7.4 7.9 8.2 9.0 8.6 7.9 TS, MPa 11.8 11.9 12.0 12.1 12.1 12.1 11.9 EB, % 290 183 289 310 310 317 286 AnTear, kN/m 13.2 15.3 19.1 22.6 25.4 22.8 17.8

TABLE-US-00007 TABLE 7 w/o add. Amount of introduced additive of Example 9 Additive 0.8 2 4 6 10 20 concentration, wt % CNT 0 0.04 0.1 0.2 0.3 0.5 1 concentration in rubber, wt % Composition of rubber mixture, parts (w/w) EPDM rubber 100 100 100 100 100 100 100 Keltan 4450 Additive 1.5 3.9 7.9 12.1 21.0 25.8 P460 oil 5.0 5.0 5.0 5.0 5.0 5.0 5.0 PEG 4000 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Chalk 10.0 10.0 10.0 10.0 10.0 10.0 10.0 White carbon 43.0 43.0 43.0 43.0 43.0 43.0 43.0 Kaolin 10.0 10.0 10.0 10.0 10.0 10.0 10.0 TiO.sub.2 5.0 5.0 5.0 5.0 5.0 5.0 5.0 ZnO 3.0 3.0 3.0 3.0 3.0 3.0 3.0 TAIC 8.0 8.0 8.0 8.0 8.0 8.0 8.0 BIPB-40-GR 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Test results for cured rubber .sub.V, Ohm .Math. m 1E+11 4.7E+08 1.3E+06 8.0E+04 220 450 11 .sub.S, Ohm/ 1E+12 6.7E+12 7.8E+10 1.0E+08 1.0E+05 1.0E+04 1.0E+03 M50, MPa 2.7 2.9 3.0 3.3 3.6 3.6 5.8 M100, MPa 4.3 4.6 4.7 4.6 4.9 5.8 6.9 M200, MPa 7.8 8.1 8.4 7.9 7.8 8.1 7.6 TS, MPa 11.8 12.0 12.3 13.3 14.0 14.2 12.4 EB, % 290 289 275 335 351 322 330 AnTear, kN/m 13.2 15.2 16.2 18.2 24.5 29.9 44.6

TABLE-US-00008 TABLE 8 Comp. examples Invention examples Additive of 2 9 35 36 37 38 Example No. Additive, wt % 6 6 6 10 10 10 CNT 0.3 0.3 0.3 0.5 0.5 0.5 concentration in rubber, wt % Composition of rubber mixture, parts (w/w) EPDM rubber 100 100 100 100 100 100 100 Keltan 4450 Additive 12.1 12.1 12.1 21.0 21.0 21.0 P460 oil 5.0 5.0 5.0 5.0 5.0 5.0 5.0 PEG 4000 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Chalk 10.0 10.0 10.0 10.0 10.0 10.0 10.0 White carbon 43.0 43.0 43.0 43.0 43.0 43.0 43.0 Kaolin 10.0 10.0 10.0 10.0 10.0 10.0 10.0 TiO.sub.2 5.0 5.0 5.0 5.0 5.0 5.0 5.0 ZnO 3.0 3.0 3.0 3.0 3.0 3.0 3.0 TAIC 8.0 8.0 8.0 8.0 8.0 8.0 8.0 BIPB-40-GR 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Test results for cured rubber .sub.V, Ohm .Math. m 1E+11 6.3E+06 2.7E+01 3.4E+02 7.4E+08 1.8E+05 2.9E+06 .sub.S, Ohm/ 1E+12 5.2E+10 3.4E+05 7.2E+05 6.2E+11 7.8E+07 3.4E+10 M50, MPa 2.7 1.8 3.4 3.3 2.9 3.3 3.0 M100, MPa 4.3 4.0 5.6 5.2 4.5 4.9 4.7 M200, MPa 7.8 7.4 8.9 8.4 7.9 8.0 8.1 TS, MPa 11.8 11.9 12.4 12.2 12.0 12.8 12.1 EB, % 290 183 324 318 292 320 278 AnTear, kN/m 13.2 15.3 25.8 23.8 15.5 18.1 16.7

TABLE-US-00009 TABLE 9 Comparative examples Invention examples Additive of 2 9 9 9 9 Example Additive 6 4 6 4 6 concentration, wt % CNT 0 0 0.3 0.2 0.3 0.2 0.3 concentration in rubber, wt % Composition of rubber mixture, parts (w/w) EPDM rubber 100 100 100 100 100 100 100 Keltan 4450 Additive 11.11 7.25 11.11 6.55 9.80 CB N550 50 50 50 50 Vulcan XC-72 30 30 30 ZnO 5 5 5 5 5 5 5 Stearic acid 1 1 1 1 1 1 1 TiO.sub.2 5 5 5 5 5 5 5 P460 oil 5 5 5 5 5 5 5 MBT 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TMTD 1 1 1 1 1 1 1 Sulfur 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Test results for cured rubber .sub.V, Ohm .Math. m 120 11 190 38 0.1 0.23 0.01 .sub.S, Ohm/ 2.3E+03 4.2E+02 5.0E+03 7.7E+02 1.1E+01 1.4E+01 1.1E+01 M50, MPa 2.9 3.1 3.0 3.4 4.2 3.3 4.2 M100, MPa 5.4 5.9 5.6 6.0 6.2 5.6 6.2 M200, MPa 10.1 11.3 10.9 12.4 13.9 12.3 13.0 TS, MPa 15.8 17.4 16.2 18.7 19.7 18 18.7 EB, % 286 339 280 310 294 278 287 AnTear, kN/m 18.6 21.5 19.1 20.7 26.1 21.3 24.1

TABLE-US-00010 TABLE 10 Additive of Example None 9 9 42 42 Additive concentration, 4 6 20 30 wt % CNT concentration in 0.2 0.3 0.2 0.3 rubber, wt % Composition of rubber mixture, parts (w/w) EPDM Keltan 4450 100 100 100 67.8 39.2 Additive 8.3 12.7 41.5 63.5 Plasticizer 5.0 5.0 5.0 5.0 5.0 PEG 4000 2.0 2.0 2.0 2.0 2.0 Chalk 10.0 10.0 10.0 10.0 10.0 White carbon 43.0 43.0 43.0 43.0 43.0 Kaolin 10.0 10.0 10.0 10.0 10.0 TiO2 10.0 10.0 10.0 10.0 10.0 Phthalocyanine blue 5.0 5.0 5.0 5.0 5.0 pigment ZnO 3.0 3.0 3.0 3.0 3.0 TAIC 8.0 8.0 8.0 8.0 8.0 Peroxide (BIPB-40-GR) 3.0 3.0 3.0 3.0 3.0 Test results for cured rubber v, Ohm .Math. m 1.0E+12 7.5E+04 2.0E+03 5.3E+04 1.2E+03 s, Ohm/ 1.0E+12 1.0E+09 5.5E+05 8.2E+08 2.1E+05 M50, MPa 2.7 2.9 3.0 3.1 3.3 M100, MPa 4.3 4.6 4.7 5.0 5.2 M200, MPa 7.8 8.1 8.4 8.4 8.5 TS, MPa 11.8 12.0 12.3 12.4 12.6 EB, % 290 289 275 284 279 AngTear, kN/m 12.5 15.2 16.2 17.8 18.8

TABLE-US-00011 TABLE 11 Comparative example Invention examples Additive of 1 15 16 17 43 9 42 Example No. Additive, wt % 2 10 4 2 10 4 20 CNT 0.2 0.1 0.2 0.2 0.2 0.2 0.2 concentration in rubber, wt % Composition of rubber mixture, parts (w/w) NR SMR-10 80 80 80 80 80 66 80 51 BR22 20 20 20 20 20 20 20 20 CB N234 60 60 60 60 60 60 60 60 Nytex 4700 4 0.8 1.4 1.4 ZnO 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 Stearic acid 2 2 2 2 2 2 2 2 6PPD 1 1 1 1 1 1 1 1 TMQ 1 1 1 1 1 1 1 1 Additive 3.5 19 7.2 3.5 17.5 7.2 36 CBS 1 1 1 1 1 1 1 1 PVI 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 DPG 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Sulfur 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 Test results for cured rubber .sub.V, Ohm .Math. m 0.28 0.10 0.096 0.048 0.053 0.082 0.047 0.06 M100, MPa 3.2 3.6 3.7 4.3 4.4 4.0 4.2 3.7 M200, MPa 9.0 9.0 9.4 9.9 10.3 9.5 10.1 9.3 M300, MPa 16.1 16.1 16.5 17.1 17.2 16.5 17.1 16.4 TS, MPa 27.9 26.5 28.1 28.4 28.7 28.2 28.4 28.0 EB, % 483 463 478 474 483 476 475 480 CrTear, kN/m 107 109 112 122 129 118 125 127

TABLE-US-00012 TABLE 12 Comparative example Invention examples Additive of 1 16 17 17 25 25 Example No. Additive 2 4 2 3.8 4 7.6 concentration, wt % CNT concentration 0.2 0.2 0.2 0.38 0.2 0.38 in rubber, wt % Composition of rubber mixture, parts (w/w) NR SVR-3L 80 80 80 80 80 80 80 BR CB-24 20 20 20 20 20 20 20 CB N330 50 50 50 50 50 50 50 ZnO 3.5 3.5 3.5 3.5 3.5 3.5 3.5 Stearic acid 2 2 2 2 2 2 2 iPPD 1 1 1 1 1 1 1 Additive 3.3 6.7 3.3 6.3 6.7 13.1 CBS 1 1 1 1 1 1 1 DPG 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Sulfur 1.8 1.8 1.8 1.8 1.8 1.8 1.8 Test results for cured rubber .sub.V, Ohm .Math. m 2.8 1.2 0.27 0.20 0.074 0.057 0.027 .sub.S, Ohm/ 6.3E+4 6.1E+4 4.5E+4 1.3E+4 1.1E+4 4.2E+4 1.1E+4 M100, MPa 3.1 3.2 3.6 3.9 4.2 4.3 5.5 M200, MPa 8.2 8.2 8.5 9.1 8.9 9.2 10.2 M300, MPa 14.5 14.4 14.5 15.4 14.9 15.4 15.9 TS, MPa 27.4 26.0 27.1 26.8 25.4 27.4 27.3 EB, % 494 471 498 473 461 476 472 CrTear, kN/m 77 73 75 113 103 84 92 H, Shore A 64 64 66 66 68 68 73

TABLE-US-00013 TABLE 13 Comparative examples Invention examples Additive of 3 18 19 20 25 26 44 Example No. Additive, wt % 3 3 3 3 3 1.5 9 CNT 0.15 0.15 0.15 0.15 0.15 0.15 0.15 concentration in rubber, wt % Composition of rubber mixture, parts (w/w) NBR 100 100 100 100 100 100 100 86.7 Additive 5.4 5.4 5.4 5.4 5.4 2.66 16 CB N550 60 60 60 60 60 60 60 60 ZnO 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 Stearic acid 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 DBP 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 iPPD 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 CZ 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Sulfur 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Test results for cured rubber .sub.V, Ohm .Math. m 79 7.8 0.34 0.38 2.1 0.29 0.42 0.8 .sub.S, Ohm/ 1E+5 8.7E+4 1E+4 1E+4 7E+4 7E+3 2E+4 4E+4 M50, MPa 3.3 3.5 3.7 3.7 4.6 4.1 4.0 3.9 M100, MPa 6.5 6.5 6.8 6.7 7.8 7.4 7.2 7.1 M200, MPa 13.2 13.1 14.0 14.2 15.5 14.8 14.5 14.4 M300, MPa 19.0 18.8 19.5 19.9 21.3 21.1 21.0 19.8 TS, MPa 21.1 20.1 20.2 22.4 23.2 22.8 22.8 22.6 EB, % 354 359 326 359 346 343 330 356 AnTear, kN/m 23.3 22.4 26.9 27.9 30.5 31 29 27.4

TABLE-US-00014 TABLE 14 Comparative examples Invention examples Additive of 3 21 22 23 25 29 31 Example No. Additive, wt % 3 3 3 3 3 3 3 CNT 0.15 0.15 0.15 0.15 0.15 0.15 0.15 concentration in rubber, wt % Composition of rubber mixture, parts (w/w) NBR Perbunan 100 100 100 100 100 100 100 100 3945 Additive 5.76 5.76 5.76 5.76 5.76 5.76 5.76 SiO.sub.2 55 55 55 55 55 55 55 55 ZnO 10 10 10 10 10 10 10 10 Stearic acid 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Silane, Si69 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 TiO.sub.2 10 10 10 10 10 10 10 10 iPPD 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Sulfur 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 MBTS 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 TMTD 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Test results for cured rubber .sub.V, Ohm .Math. m 7E+8 2.5E+7 5.5E+6 1.1E+4 9.7E+3 510 2.4E+3 7.5E+3 .sub.S, Ohm/ 7E+11 7E+10 7.9E+9 2.0E+9 5.0E+9 1.6E+6 2.4E+7 4.1E+7 M50, MPa 1.8 2.1 2.9 2.9 2.9 3.2 2.9 2.7 M100, MPa 3.0 3.1 4.6 4.5 4.6 5.0 4.5 4.7 M200, MPa 6.9 7.2 9.3 9.0 9.3 10.1 10.0 9.8 M300, MPa 12.5 12.9 15.7 15.0 15.7 16.7 16.4 16.1 TS, MPa 21.1 22.2 23.5 24.2 23.2 24.1 25.9 23.9 EB, % 502 513 407 427 403 398 430 408 AnTear, kN/m 20.0 23.7 27.9 27.2 30.5 31.3 30.2 26.9

TABLE-US-00015 TABLE 15 Comparative examples Invention examples Additive of 3 32 33 34 39 40 41 Example No. Additive, wt % 6 6 6 6 3 10 10 CNT 0.3 0.3 0.3 0.3 0.3 1 1 concentration in rubber, wt % Composition of rubber mixture, parts (w/w) NBR Perbunan 100 100 100 100 100 100 100 100 3945 Additive 11.9 11.9 11.9 11.9 5.76 20.7 20.7 SiO.sub.2 55 55 55 55 55 55 55 55 ZnO 10 10 10 10 10 10 10 10 Stearic acid 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Silane, Si69 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 TiO.sub.2 10 10 10 10 10 10 10 10 iPPD 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Sulfur 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 MBTS 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 TMTD 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Test results for cured rubber .sub.V, Ohm .Math. m 6.6E+8 2.6E+3 56 59 74 46 2.1E+4 1.6E+3 .sub.S, Ohm/ 7E+11 5.6E+7 1.6E+4 3E+4 5.2E+4 1.2E+4 1.6E+7 7E+6 M50, MPa 1.8 2.2 3.2 3.0 3.1 3.4 2.4 2.8 M100, MPa 3.0 3.4 4.8 4.3 4.6 4.9 3.9 4.2 M200, MPa 6.9 7.0 8.9 8.5 8.6 9.8 7.1 8.8 M300, MPa 12.5 11.8 14.3 13.9 14.0 15.8 12.9 13.7 TS, MPa 21.1 20.8 25.4 24.1 24.2 25.6 24.5 23.8 EB, % 502 520 407 452 470 446 513 490 AnTear, kN/m 20.0 23.6 27.9 27.5 28.2 34.2 28.6 29.5

TABLE-US-00016 TABLE 16 Comp. examples Invention examples Additive of 4 9 22 26 27 28 Example No. Additive, wt % 3.7 7.5 7.5 3.7 2.5 1.9 CNT 0.37 0.38 0.38 0.37 0.38 0.38 concentration in rubber, wt % Composition of rubber mixture, parts (w/w) BR CB-24 27 27 27 27 27 27 27 SBR 100 100 100 100 100 100 100 Additive 9.2 19 19 9.2 6.2 4.7 SiO.sub.2 85 85 85 85 85 85 85 Silane TESPT 6.8 6.8 6.8 6.8 6.8 6.8 6.8 Stearic acid 2 2 2 2 2 2 2 TDAE oil 13 5 5 9 11 ZnO 2.4 2.4 2.4 2.4 2.4 2.4 2.4 iPPD 3.5 3.5 3.5 3.5 3.5 3.5 3.5 TBBS 3 3 3 3 3 3 3 Sulfur 1 1 1 1 1 1 1 DPG 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Test results for cured rubber .sub.V, Ohm .Math. m 1E+11 1E+11 80 140 140 120 240 .sub.S, Ohm/ 1E+12 1E+11 2E+06 7E+06 3E+7 3E+7 6E+7 M50, MPa 1.4 1.6 2.6 2.4 2.3 2.4 2.2 M100, MPa 2.6 2.9 3.8 3.7 3.9 3.6 3.4 M200, MPa 7.0 7.1 7.5 8.5 8.6 8.3 8.1 M300, MPa 13.3 13.2 13.4 14.6 14.9 14.0 13.8 TS, MPa 19.2 17.5 19.2 19.6 19.6 19.5 19.2 EB, % 389 365 387 378 370 392 371 CrTear, kN/m 30.5 32.7 36.7 52.5 46.1 44.5 42.0 H, Shore A 58.8 65.2 65.7 72 73.8 74.0 69.5

TABLE-US-00017 TABLE 17 Comp. examples Invention examples Additive of 4 24 25 25 25 45 Example No. Additive, wt % 3.7 7.5 3.0 5.0 7.5 22.2 CNT in rubber, 0.37 0.38 0.15 0.25 0.38 0.38 wt % Composition of rubber mixture, parts (w/w) BR CB-24 27 27 27 27 27 27 27 SBR 100 100 100 100 100 100 54 Additive 9.2 19 7.5 12.6 19 55.2 SiO.sub.2 85 85 85 85 85 85 85 Silane TESPT 6.8 6.8 6.8 6.8 6.8 6.8 6.8 Stearic acid 2 2 2 2 2 2 2 TDAE oil 13 5 7 3 5 ZnO 2.4 2.4 2.4 2.4 2.4 2.4 2.4 iPPD 3.5 3.5 3.5 3.5 3.5 3.5 3.5 TBBS 3 3 3 3 3 3 3 Sulfur 1 1 1 1 1 1 1 DPG 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Test results for cured rubber .sub.V, Ohm .Math. m 1E+11 1E+11 120 N/D 1E+5 8.0 2E+4 .sub.S, Ohm/ 1E+12 .sup.1E+11 3.0E+6 2.0E+11 9E+9 1.2E+6 3.0E+8 M50, MPa 1.4 1.6 2.8 2.1 2.6 2.7 2.5 M100, MPa 2.6 2.9 4.1 3.4 4.1 4.3 3.9 M200, MPa 7.0 7.1 7.7 7.8 8.8 8.9 8.3 M300, MPa 13.3 13.2 13.1 14.1 15.5 15.1 14.4 TS, MPa 19.2 17.5 21.4 19.5 21.2 22.0 19.8 EB, % 389 365 449 382 388 409 389 CrTear, kN/m 30.5 32.7 77.0 45.2 68.4 68.9 53.7 , W/(m .Math. K) 0.181 0.180 0.196 0.190 0.192 0.198 0.194 tan(), 0 C. 0.145 0.15 0.205 0.18 0.20 0.22 0.21

INDUSTRIAL APPLICATION

[0110] The present invention can be used in production of rubber compounds and provides rubber with enhanced electrical conductivity and physical and mechanical properties.

[0111] Having thus described a preferred embodiment, it should be apparent to those skilled in the art that certain advantages of the described method and apparatus have been achieved.

[0112] It should also be appreciated that various modifications, adaptations, and alternative embodiments thereof may be made within the scope and spirit of the present invention. The invention is further defined by the following claims.

PATENT LITERATURE

[0113] Patent literature 1: Patent RU 2731635 C [0114] Patent literature 2: Patent EP 2436720 B1 [0115] Patent literature 3: Patent RU 2619782 C2 [0116] Patent literature 4: Patent RU 2654959 C2 [0117] Patent literature 5: Patent RU 2607407 B1