RU2431641C2 - Method of producing modified rubber mixtures - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: rubber mixture containing tyre reclaim and plasticiser is mixed with a regeneration product obtained by bringing rubber crumbs into contact with nitrous oxide (N₂O) at 120-350°C and nitrous oxide pressure from 3 to 140 atm. The rubber mixture is modified by replacing 25-99.5 wt % of the tyre reclaim in the rubber mixture with a regeneration product obtained using nitrous oxide.

EFFECT: invention improves processing characteristics of rubber mixtures and improves strength properties of rubber obtained by vulcanising rubber mixtures, in particular, modification of the disclosed coating rubber mixtures significantly increases the strength of the bond between the coating rubber and tyre cord.

10 cl, 9 tbl, 10 ex

Description

The invention relates to a method for producing modified rubber compounds containing tire regenerate using regeneration products (tire regenerates) obtained by treating rubber waste with nitrous oxide (N ₂ O), namely tire rubbers and used car tires. More specifically, the invention describes a method for producing modified rubber compounds, which is carried out by introducing into the rubber mixture a tire regenerate obtained by contacting a rubber tire crumb with nitrous oxide.

In recent years, many countries have devoted considerable attention to the problem of the disposal of rubber waste. The most large-capacity waste of this type are obsolete car tires. So, according to [Pat. Appl. US No. 2007/0004812, C08J 11/04, B01D 11/02, B29B 17/02, 01/04/2007] in the world annually accumulate about 15 million tons of tires (about 1 billion units). Therefore, the processing and recycling of such waste are especially relevant.

The most rational way of rubber processing is its regeneration - processing into products (regenerates), which can be reused to replace rubbers in the composition of elastomeric compositions and rubber preparation. Regeneration is based on the devulcanization (degradation of the vulcanization network) of rubber, which can be carried out by chemical, thermomechanical and other methods [Kirk-Othmer Encyclopedia of Chemical Technology, 4th Ed., Vol.21 1997, John Wiley & Sons, NY, 12-21].

For example, rubber devulcanization can be carried out by chemical methods under the action of organic [Pat. US 4,544,675, C08F 11/28, C08J 11/00, 10/10/1985, J. Anderson; US Pat. Apl. 2004/0132841, C08J 11/00, 8.7.2004, D.A. Benko et al.] Or inorganic [Pat. US 5602186, C08J 11/16, 02/11/1997, R. D. Myers et al.] Devulcanizing agents at elevated temperature and pressure.

Devulcanization can also be carried out by thermomechanical methods using high-speed extruders in the presence of regenerating agents [US Pat. Apl. 2005/0203197, C08F 11/04, C09K 3/00, 09/15/2005, Y. Tang] or without their addition [Pat. US 2653349, B29B 17/00, 09/29/1953, J. C. Elgin et al.].

In addition, methods of devulcanization based on the use of microwave radiation are known [Pat. US 4104205, C08J 11/00, C08F 2/46, 1.08.1978, D.S. Novotny et al.] Or ultrasound [Pat. US 5284625, C08J 11/00, C08F 2/40, 02/08/1994, A. Isayev et al.].

It should be noted that the regeneration products (bus regenerates) obtained by these methods, as a rule, are not of high enough quality for their widespread use [Kirk-Othmer Encyclopedia of Chemical Technology, 4th Ed., Vol. 21 1997, John Wiley & Sons, NY, 12-21].

Some patents show the possibility of using rubber regeneration products (tire regenerate) as a component of rubber compositions [US Pat. Apl. 2004/0132841, C08J 11/16, 8.7.2004, D. A. Benko et al., US Pat. Apl. 2005/0203197, C08J 11/04, 09/15/2005, Y. Tang]. However, vulcanizates obtained using such products, as a rule, have insufficiently high strength characteristics.

The invention solves the problem of improving the technological characteristics of rubber mixtures containing tire regenerate, as well as improving the strength characteristics of rubber obtained by vulcanization of such mixtures.

The present invention describes a new method for producing modified rubber compounds containing tire regenerate.

A method for producing modified rubber compounds containing a tire regenerate and a plasticizer is proposed, in which a tire regenerate is obtained that is obtained by contacting rubber crumb with nitrous oxide (N ₂ O) at a temperature of 120-350 ° C and a nitrous oxide pressure of 3 to 140 atm.

A method for producing modified rubber compounds containing a tire regenerate is proposed, in which a tire regenerate obtained by contacting rubber crumb with nitrous oxide (N ₂ O) at a temperature of 120-350 ° C and a nitrous oxide pressure of 3 to 140 atm is introduced into the rubber mixture and the rubber mixture is prepared without the addition of a plasticizer.

To obtain a modified rubber composition from 25 to 100 wt.% Tire regenerate in the rubber composition is replaced by a tire regenerate obtained with nitrous oxide.

To obtain a modified rubber composition, a tire regenerate is used containing from 0.5 to 3.0 wt.% Oxygen introduced from nitrous oxide.

Modified rubber compounds are subjected to vulcanization to obtain rubber.

Tire regenerate obtained with nitrous oxide is used to prepare modified lining rubber compounds in order to increase the bond strength of lining rubber with steel cord.

According to the proposed method, the production of modified rubber compounds is carried out by introducing into the rubber mixture the regeneration products (regenerates) obtained by the patent [RU 2362795, C10G 1/10, C08J 11/04, 07/27/09, Dubkov K.A. et al.] by treatment with nitrous oxide (N ₂ O) of rubber-containing waste, namely tire rubbers and used car tires. According to the patent [RU 2362795] the processing of rubber waste, for example tire rubber crumb, nitrous oxide or N ₂ O-containing gas is carried out at a temperature of 120-350 ° C and a pressure of N ₂ O from 3 to 140 atm.

Depending on the conditions and the intensity of the process, the regeneration products (tire regenerates) obtained by this method can have a different consistency: from viscous to liquid. In addition, varying the processing conditions allows one to obtain regeneration products with a controlled oxygen content introduced from N ₂ O into the rubber component of rubber in the form of polar carbonyl groups [S.V. Semikolenov, K.A. Dubkov, D.P. Ivanov, V. D.Voronchikhin, G.I. Panov // A new method for processing used tires using nitrous oxide // XIV International Conference “Rubber Industry. Raw materials. Materials ”, Moscow May 19-23, 2008, p.207-209]. This gives important advantages for regulating the properties of rubber compounds and rubbers modified with such products according to the proposed method.

Used in the proposed method, the regeneration products (bus regenerates) have a set of important characteristics. Due to the presence of polar oxygen-containing groups in their composition, they have high adhesion to various materials. Due to the relatively low viscosity, they can be mixed with various ingredients and fillers in the rubber compositions, and also play the role of a plasticizer. Therefore, their introduction into the composition of rubber compounds allows to obtain polymer compositions with improved technological and operational characteristics, in particular with increased ductility, improved adhesive and strength properties. Such properties are especially important in the case of rubber-cord systems where a high bond strength of the lining rubbers with the cord is required.

In addition to carbonyl groups, these regeneration products contain double carbon-carbon bonds [S.V.Semikolenov, K.A.Dubkov, D.P. Ivanov, V.D. Voronchikhin, G.I. Panov // New method for processing used tires with using nitrous oxide // XIV international conference “Rubber industry. Raw materials. Materials. ”, Moscow May 19-23, 2008, p.207-209]. Therefore, they have good compatibility with various types of high molecular weight rubbers, and are also easily vulcanized in rubber compositions.

According to the proposed method, regeneration products (tire regenerates), which can be used to obtain modified rubber compounds and their vulcanizates, may contain from 0.5 to 3 wt.% Oxygen. Depending on the oxygen content, they are plastic or viscous products.

In accordance with this invention, the production of modified rubber compounds containing tire regenerate is carried out by replacing from 25 to 100 wt.% Tire regenerate in the rubber composition with a tire regenerate obtained by treating crumb rubber with nitrous oxide.

According to the proposed method, the production of modified rubber compounds can be carried out without the addition of a plasticizer, since the tire regenerate obtained with nitrous oxide has a relatively low viscosity.

To rubber compounds and rubbers that can be obtained by the proposed method include rubber compounds and rubbers containing tire regenerate. Such rubber compounds and rubbers may additionally contain high molecular weight rubbers of various types, for example natural rubber.

According to this invention, a modified rubber composition can be prepared by simultaneously or sequentially mixing all the necessary components (rubbers, tire regenerate, regeneration product (tire regenerate) obtained by treating rubber crumb with nitrous oxide, fillers, vulcanizing agents, plasticizers, etc. .).

Modified rubber composition can also be prepared by adding tire regenerate obtained using N ₂ O in the finished rubber composition with their subsequent mixing. The mixing of the components at all stages of the manufacture of the modified rubber composition is carried out on standard mixing equipment, such as rollers, rotary or screw mixers.

In the General case, the receipt of modified rubber compounds is as follows. All components of the mixture are pre-dosed. The regeneration product obtained with N ₂ O is mixed with high molecular weight rubber and tire regenerate. Then, fillers, plasticizers, stabilizers, vulcanizing additives and other necessary components are added to the mixture. The resulting rubber mixture is molded and subjected to isothermal vulcanization to obtain rubber (vulcanizate).

In accordance with this invention, the introduction into the rubber composition of a tire regenerate obtained by treating rubber crumb with nitrous oxide reduces the viscosity of rubber compounds based on high molecular weight carbochain polymers. This improves the technological properties of rubber compounds and facilitates their processing at the stage of mixing the components and molding of various products. In addition, the proposed method simultaneously provides an increase in the strength characteristics of rubbers obtained by vulcanization of modified rubber compounds. In particular, obtaining modified lining rubber mixtures according to the proposed method can significantly increase the bond strength of lining rubber with a metal cord.

The invention is illustrated by the following examples.

Example 1

This example demonstrates the production of a modified rubber compound and rubber based on industrial tire regenerate (symbol RSh-1, Chekhov Regenerate Plant OJSC, Chekhovo, Moscow Region). To obtain a modified rubber composition according to the proposed method, a tire regenerate R-1 is used - the regeneration product obtained according to the patent [RU 2362795, K. Dubkov. et al.] by processing tire rubber crumbs using nitrous oxide. For its preparation, rubber crumb with a particle size of 2-3 mm, obtained by mechanical grinding of used truck tires (Avtosnab company, Novosibirsk) is used. The rubber crumb (160 g) is treated with nitrous oxide (2 mol) in the presence of a solvent (toluene, 1000 cm) in a reactor with a volume of 2000 cm ³ (Parr) at 230 ° C for 1 h and a pressure of N ₂ O 40 atm.

After the reaction is completed, a plastic regenerate P-1 containing 0.3 wt.% Oxygen introduced from N ₂ O is isolated from the toluene solution.

The compositions of the standard rubber compound (TU 38.108053-89) and the modified mixture are shown in table 1. The modified rubber mixture according to the proposed method is obtained by completely replacing (100 wt.%) Tire regenerate RSh-1 in the composition of the standard rubber mixture with regenerate R-1 ( Table 1). The total mixing time is 20 minutes The measurement of the vulcanization-kinetic characteristics of the mixtures is carried out at a temperature of 143 ° C.

Table 1 The composition of the rubber mixture containing tire regenerate (TU 38.108053-89) Component The composition of the rubber mixture (wt. Parts) Standard mix Modified mixture with the replacement of 100% RSh-1 by P-1 (example 1) RSh-1 one hundred - R-1 - one hundred Thiazole 2MBS (Altax) 0.9 0.9 Zinc white 2.5 2.5 Sulfur technical 1.5 1.5

Table 2 shows that the introduction of the regenerate R-1 according to the proposed method improves the performance of the rubber composition, as it results in a modified mixture with a lower viscosity compared to the standard mixture, which is reflected in a decrease in the minimum torque. In addition, the modified mixture has a higher vulcanization rate.

table 2 Vulcanization-kinetic characteristics of rubber compounds Indicators Standard mix Modified mixture replacement of 100% RSh-1 with P-1 (example 1) replacement of 100% RSh-1 with P-2 (example 2) replacement of 25% RSh-1 with P-3 (example 3) Minimum Torque (Nm) 0.21 0.07 0.07 0.12 The rate of vulcanization (% / min) 27.3 30.8 38.9 32.6

Table 3 shows the characteristics of the rubber obtained by vulcanization of raw rubber compounds at a temperature of 143 ° C. It is seen that the modified rubber obtained from the mixture modified by the proposed method has several advantages compared to standard rubber based on industrial regenerate RSh-1.

Table 3 Physico-mechanical characteristics of vulcanizates containing tire regenerate Indicators Standard rubber Modified rubber replacement of 100% RSh-1 with P-1 (example 1) replacement of 100% RSh-1 with P-2 (example 2) replacement of 25% RSh-1 with P-3 (example 3) Tensile Strength (MPa) 7.3 8.0 8.2 7.5 Elongation at break (%) 227 285 295 240 Shore A hardness (conventional units, n.o.) 62 64 64 63 Conv. strength after 24 hours of aging (MPa) 6.3 7.9 7.8 7.2

The proposed method leads to rubber with a higher elongation at break (285%), higher tensile strength at break (8 MPa) and hardness (64 conventional units). In addition, the modified rubber has a higher resistance to thermal aging.

Example 2

This example is similar to example 1 with the difference that to obtain a modified rubber mixture and rubber, P-2 tire regenerate is used, obtained by treating rubber crumb with nitrous oxide (1 mol) at 230 ° C for 6 h and a pressure of N ₂ O 20 atm . Regenerate P-2 is a plastic product containing 0.9 wt.% Oxygen introduced from N ₂ O.

Table 2 shows that the introduction of P-2 regenerate improves the performance of the rubber composition, resulting in a modified mixture with a lower viscosity compared to the standard mixture, which translates into a reduction in minimum torque. At the same time, the modified mixture has a higher vulcanization rate.

Table 3 shows that the proposed method simultaneously provides a modified rubber with higher elongation at break (295%), higher tensile strength at break (8.2 MPa) and hardness (64 conventional units), as well as with higher resistance thermal aging compared to standard rubber.

Example 3

This example is similar to example 1 with the difference that to obtain a modified rubber mixture and rubber, P-3 tire regenerate is used, obtained by treating rubber crumb with nitrous oxide (3 mol) at 230 ° C for 6 h and a pressure of N ₂ O 60 atm . Regenerate P-3 is a viscous product containing 2.9 wt.% Oxygen introduced from N ₂ O. The modified rubber composition according to the proposed method is obtained by replacing 25 wt.% Tire regenerate RSh-1 in a standard rubber composition with regenerate P-3 .

Table 2 shows that the modified rubber composition containing P-3 regenerate also has a lower viscosity (minimum torque) and a higher vulcanization rate compared to the standard mixture.

Table 3 shows that the proposed method simultaneously provides a modified rubber with higher elongation at break (240%), higher tensile strength at break (7.5 MPa) and hardness (63 srvc. Units), as well as with higher resistance thermal aging compared to standard rubber.

Example 4

This example is similar to example 1 with the difference that the tire regenerate R-1, containing 0.3 wt.% Oxygen, is used to obtain a modified rubber composition and rubber for insulating the side ring wire of large tires. The composition of the standard mixture (table 4) includes natural rubber, rubber SKMS-30ARM-15 and industrial tire regenerate RSh-1. The modified rubber mixture according to the proposed method is obtained by completely replacing (100 wt.%) Tire regenerate RSh-1 as part of a standard rubber mixture with regenerate R-1 (table 4).

Table 4 The composition of the rubber composition containing the tire regenerate for insulation of the side ring wire of large tires Component The composition of the rubber mixture (wt. Parts) Standard mix Modified mixture with the replacement of 100% RSh-1 by P-1 (example 4) Natural rubber fifty fifty SKMS-30ARM-15 fifty fifty Regenerate RS one hundred - Regenerate R-1 - one hundred Rhombic sulfur 7.5 7.5 Thiazole 2MBS one one Zinc White four four Burnt magnesia one one Stearin one one Oleic acid one one Pine Rosin 5 5 Oil bitumen 40 40 Carbon black P514 125 125

From table 5 it is seen that the proposed method improves the performance of the rubber compound. The introduction of P-1 regenerate lowers the viscosity of the mixture, which is reflected in a decrease in minimum torque, and also increases the plasticity of the mixture. The rate of vulcanization increases slightly compared to a mixture of standard composition.

Table 5 Rheological and vulcanization-kinetic characteristics (143 ° С) of rubber compounds containing tire regenerate Indicators Standard mix Modified mixture replacement of 100% RSh-1 with P-1 (example 4) replacement of 50% RSh-1 with P-2 (example 5) replacement of 25% RSh-1 with P-3 (example 6) Plasticity (conventional units) 0.15 0.19 0.21 0.32 Minimum Torque (Nm) 0.48 0.34 0.31 0.29 The rate of vulcanization (% / min) 10.0 12.1 10.5 11.7

The characteristics of the rubbers obtained by vulcanization of crude rubber mixtures at a temperature of 143 ° C are shown in table 6. It can be seen that the proposed method leads to a modified rubber, which has several advantages compared to the elastomeric composition of a standard composition. The introduction of R-1 regenerate leads to an increase in the conditional strength at break from 20.1 to 22.2 MPa and elongation from 285 to 295%. The hardness of the vulcanizate is practically unchanged. The most important positive effect of the proposed method is a significant increase in the bond strength of rubber with wire (from 164 to 243 N).

Table 6 Physico-mechanical characteristics of vulcanizates containing tire regenerate Indicators Standard rubber Modified rubber replacement of 100% RSh-1 with P-1 (example 4) replacement of 50% RSh-1 with P-2 (example 5) replacement of 25% RSh-1 with P-3 (example 6) Tensile Strength (MPa) 20.1 22.2 20.5 21.0 Elongation at break (%) 285 295 290 300 Shore A hardness (conventional units, n.o.) 81 82 82 81 The bond strength of rubber with wire 1 l (N) 164 243 230 190

Example 5

This example is similar to example 4 with the difference that the modified rubber mixture according to the proposed method is obtained by replacing 50 wt.% Tire regenerate RSh-1 in the composition of a standard rubber mixture with regenerate R-2 (example 2) containing 0.9 wt.% Oxygen.

From table 5 it is seen that the proposed method increases the ductility of the rubber compound and lowers the minimum torque, that is, the viscosity of the mixture. The strength characteristics of the modified rubber (conditional tensile strength, elongation, hardness) are increased compared to standard rubber (table 6). At the same time, the bond strength of the modified rubber with the wire increases significantly, reaching 230 N.

Example 6

This example is similar to example 4 with the difference that the modified rubber mixture according to the proposed method is obtained by replacing 25 wt.% Industrial tire regenerate RSh-1 as part of a standard rubber mixture with regenerate P-3 (example 3) containing 2.9 wt.% Oxygen .

From table 5 it is seen that the proposed method increases the ductility of the rubber compound and lowers the minimum torque, that is, the viscosity of the mixture. Modified rubber obtained by vulcanization of the modified mixture has a higher conditional strength and elongation at break, as well as a higher bond strength with wire compared to standard rubber (table 6).

Example 7

This example is similar to example 1 with the difference that to obtain a modified rubber compound and rubber using a standard rubber mixture (table 7), which contains industrial tire regenerate RSh-2 (LLC Templar Center, Chernogorsk, Republic of Khakassia), rubber SKMS-30ARM-15 and is intended for the manufacture of molded products. As a plasticizer, this mixture contains Netoxol oil. The modified rubber mixture according to the proposed method is obtained by completely replacing (100 wt.%) Tire regenerate RSh-2 as part of a standard rubber mixture with regenerate R-3 (example 3) containing 2.9 wt.% Oxygen.

Table 7 The composition of the rubber composition for molded products containing tire regenerate Component The composition of the rubber mixture (parts by weight) Standard mix Modified mixture with the replacement of 100% RSh-2 by P-3 (example 7) SKMS-30ARM-15 62.5 62.5 RSh-2 12.5 - R-3 - 12.5 Ground sulfur 0.31 0.31 Thiazole 2MBS 0.63 0.63 Acetononil P 1.25 1.25 Zinc white 0.94 0.94 Kaolin 31.25 31.25 Carbon black P 701 37.5 37.5 Wax ЗВ-1 3.125 3.125 Stearin 1.25 1.25 Tiuram D 1.13 1.13 Kaolin 1.13 1.13 Netoxol Oil 8 8

Table 8 shows that the proposed method improves the characteristics of the rubber compound, as it increases its ductility and lowers the minimum torque, that is, the viscosity of the mixture. The vulcanization rate of the modified rubber composition is reduced compared to a standard composition.

Table 8 Rheological and vulcanization-kinetic characteristics (155 ° С) of rubber compounds containing tire regenerate Indicators Standard mix Modified mixture replacement of 100% RSh-2 with P-3 (example 7) replacement of 50% RSh-2 with P-3 (example 8) replacement of 100% RSh-2 with R-3, without oil (example 9) replacement of 100% RSh-2 with R-1, without oil (example 10) Plasticity (conventional units) 0.57 0.65 0.63 0.61 0.6 Minimum Torque (Nm) 0.12 0.09 0.1 0.11 0.11 The rate of vulcanization (% / min) 36.4 22.0 24.7 29.4 33.3

Table 9 Physico-mechanical characteristics of vulcanizates containing tire regenerate Indicators Standard rubber Modified rubber replacement of 100% RSh-2 with P-3 (example 7) replacement of 50% RSh-2 with P-3 (example 8) replacement of 100% RSh-2 with R-3, without oil (example 9) replacement of 100% RSh-2 with R-1, without oil (example 10) Tensile Strength (MPa) 5.1 6.0 5.7 5.8 5.4 Elongation at break (%) 688 760 743 700 695 Resistance
tear (kN / m) 22.6 30.7 28.2 35.6 31.4 Abrasion
(m ³ / MJ) 4.2 4.0 3.9 2.3 3.7 Shore A hardness (conventional units, n.o.) 45 48 47 54 55

The characteristics of the rubber obtained by vulcanization of raw rubber compounds at a temperature of 155 ° C are shown in table 9. It can be seen that the proposed method leads to a significant improvement in the strength characteristics of the vulcanizate compared to standard rubber. The introduction of P-3 regenerate leads to an increase in the conditional tensile strength at break from 5.1 to 6 MPa, elongation from 688 to 760%, tensile strength from 22.6 to 30.7 kN / m, hardness from 45 to 48 conv. units At the same time, the proposed method reduces the abrasion of rubber.

Example 8

This example is similar to example 7 with the difference that the modified rubber mixture according to the proposed method is obtained by replacing 50 wt.% Tire regenerate RSh-2 in the composition of a standard rubber mixture to regenerate R-3.

Tables 8 and 9 show that the proposed method improves the performance of the rubber compound, increasing its ductility and lowering viscosity (minimum torque), and also leads to a significant improvement in the strength characteristics of the vulcanizate (conditional tensile strength, elongation, tensile strength, hardness and abrasion ) compared to standard rubber.

Example 9

This example is similar to example 7 with the difference that a modified rubber mixture containing P-3 regenerate is prepared without the addition of a plasticizer (Netoxol oil).

Tables 8 and 9 show that the proposed method improves the performance of the rubber compound, increasing its ductility and lowering viscosity (minimum torque), and also leads to a significant improvement in the strength characteristics of vulcanizate compared to standard rubber.

Example 10

This example is similar to example 9 with the difference that the modified rubber mixture according to the proposed method is obtained by completely replacing (100 wt.%) Tire regenerate RSh-2 in the composition of the rubber mixture with regenerate P-1 (example 1) containing 0.3 wt.% oxygen. The modified mixture is also prepared without the addition of a plasticizer (Netoxol oil).

Table 8 shows that the proposed method also increases ductility and lowers the viscosity (minimum torque) of the rubber compound. From table 9 it is seen that the proposed method simultaneously leads to an improvement in the strength characteristics of the vulcanizate in comparison with standard rubber.

Claims (10)

1. A method of producing modified rubber compounds containing a tire regenerate and a plasticizer, characterized in that the regeneration product obtained by contacting the rubber crumb with nitrous oxide (N ₂ O) at a temperature of 120-350 ° C and nitrous oxide pressure from 3 to 140 atm. 2. The method according to claim 1, characterized in that to obtain a modified rubber composition from 25 to 99.5 wt.% Tire regenerate in the rubber composition is replaced by a regeneration product obtained with nitrous oxide. 3. The method according to claim 1, characterized in that to obtain a modified rubber compound, a regeneration product is used containing from 0.5 to 3.0 wt.% Oxygen introduced from nitrous oxide. 4. The method according to claim 1, characterized in that the modified rubber composition is subjected to vulcanization to obtain rubber. 5. The method according to claim 1, characterized in that the regeneration product obtained using nitrous oxide is used to prepare modified lining rubber mixtures in order to increase the bond strength of lining rubber with metal cord. 6. A method of producing modified rubber compounds containing a tire regenerate, characterized in that a regeneration product is introduced into the rubber mixture obtained by contacting the rubber crumb with nitrous oxide (N ₂ O) at a temperature of 120-350 ° C and a nitrous oxide pressure of 3 to 140 atm, and the rubber mixture is prepared without the addition of a plasticizer. 7. The method according to claim 6, characterized in that to obtain a modified rubber composition from 25 to 99.5 wt.% Tire regenerate in the rubber composition is replaced by a regeneration product obtained with nitrous oxide. 8. The method according to claim 6, characterized in that to obtain a modified rubber compound, a regeneration product is used containing from 0.5 to 3.0 wt.% Oxygen introduced from nitrous oxide. 9. The method according to claim 6, characterized in that the modified rubber composition is subjected to vulcanization to obtain rubber. 10. The method according to claim 6, characterized in that the regeneration product obtained with nitrous oxide is used to prepare modified lining rubber mixtures in order to increase the bond strength of lining rubber with metal cord.