THE PRODUCED MODIFIED POLYDIENES

Technical field

The invention relates to the industry of synthetic rubbers used in the manufacture of tires, industrial rubber goods, in the electrical engineering and other fields. In particular, the present invention relates to a method for producing modified polydienes in an organic solvent on a catalyst system comprising a lanthanide compound, an organoaluminum compound, and a halogen-containing component, followed by terminal modification of the produced "pseudo-living" polymer with at least one compound selected from the group of heterocyclic nitrogen-containing compounds. The present invention also relates to modified polydienes produced by this method. In addition, the invention relates to rubber mixtures based on the produced polydienes .

The produced modified polydiene is characterized by a high modification degree (less than 90%) , a high content of 1 , -cis-units , and a narrow molecular-weight distribution, and an improved processability at the step of rubber mixing; rubbers based on the polymer according to the invention have an increased wear-resistance and improved physical and mechanical properties, as well as improved elastic-hysteresis properties (rolling resistance, wet-tire traction) .

Background

The main field of application of conjugated diene- based polymers is the tire industry. One of the requirements to the modern tires is wear-resistance, tire traction on wet and icy roads, and low rolling resistance that leads to a reduction in fuel consumption. One of the solutions to the above problems is the introduction of functional groups in a rubber molecule, i.e. modification. The presence of functional groups in the structure of a polymer can reduce the number of free polymer chain ends, an improved interaction with fillers, prevents agglomeration of their particles, and, as a consequence, increases the wear-resistance of tread rubbers and reduces hysteresis loss (Kuperman F.E., Novye kauchuki dlya shin. Prioritetnye trebovaniya. Mrtody otsenki. [New rubbers for tires. Priority requirements. Methods for estimation.] Nauchno-Tekh. Tsentr "NHShP" , Moscow, 2005, p.329) .

The most common method for producing modified polymers is post-polymerization treatment of reactive polymers - terminal modification. This approach is commonly used in the industry and is disclosed in detail in scientific literature and in Russian and foreign patents.

Patent RU2425845 discloses a modified polymer produced by polymerization of a conjugated diene in the presence of a catalyst comprising a lanthanide rare-earth element compound in an organic solvent, followed by modification of the produced polymer comprising an active organic metal site, with a modifier that comprises a functional group capable of entering into substitution or addition reactions with the active organic metal site of the polymer. The used modifier has at least one functional group selected from the group consisting of an azacyclopropane group, ketone groups, carboxyl groups, thiocarboxyl groups, carbonates, carboxylic anhydrides, carboxylic acid metal salts, acid halides, urea groups, thiourea groups, amido groups, thioamido groups, isocyanate groups, thioisocyanate groups, haloisocyano groups, epoxy groups, thioepoxy groups, imino groups, and a M-Z bond (where M is Sn, Si, Ge, or P, and Z is a halogen atom) , and contains neither active proton nor onium salt that deactivates the active organic metal site.

A disadvantage of the method is its high-energy consumption. In particular, it is proposed to carry out polymerization at (-78) to 25°C, but since the method is exothermic, the polymerization in this temperature range requires removal of heat. In addition, aluminoxanes proposed as an alkylating agent increase the ash content in the rubber and makes the final product expensive.

Patent US7642322 discloses a method for preparing functionalized 1 , 4 -cis-polybutadienes . The method comprises the following steps: 1) preparing a pseudo-living polymer by polymerizing conjugated diene monomer with a lanthanide- based catalyst; and 2) reacting the pseudo- living polymer with at least one functionalizing agent defined by the formula :

A-F^-Z,

where R ¹ is a divalent bond or divalent organic group comprising from 0 to about 20 carbon atoms, A is a substituent that will undergo an addition reaction with a pseudo- living polymer, and Z is a substituent that will react with silica or carbon black reinforcing fillers, with the proviso that A, R ¹ , and Z are substituents that will not protonate a pseudo- living polymer. Said substituent A in the above formula is a compound selected from the group of ketones, aldehydes, amides, esters, and imidazolidines , as well isocyanates and isothiocyanates . These groups include amide isocyanurate groups.

However, according to this patent, the catalyst system comprises aluminoxanes or a mixture of aluminoxane with trialkylaluminum or dialkylaluminum hydride . The use of this catalyst system makes the product very expensive. Another disadvantage of the method is a high dose of the functionalizing agent, which also leads to a high cost of the product. In industrial production, an excess of the functionalizing agent may accumulate in the circulating solvent, and the reuse of this solvent will inhibit the polymerization process.

Patent RU2486209 discloses a method for preparing functionalized polymers, in particular, describes variants of the method for preparing a functionalized polymer, comprising the following steps: (a) polymerizing a conjugated diene monomer optionally together with monomers copolymerizable with conjugated diene, in the presence of a coordination catalyst to form a polymer; (b) inhibiting said polymerization step with a Lewis base; and (c) reacting the polymer with a functionalizing agent different from the Lewis base used at step (b) .

The technical result of the method is to inhibit the polymerization without deleteriously impacting the ability of the reactive polymer to react with a functionalizing agent, to reduce a risk of uncontrolled polymerization, and to reduce the fouling of equipment.

However, this method is effective only in polymerization in oil when the conversion of monomers (and, molecular weight, respectively) is hardly controllable. Since temperature control can be very difficult, local hot spots may occur in the polymerization mixture, which may lead to gel formation. In solution polymerization, it is important to reach the maximum conversion efficiency to reduce the costs for processing the recycled solvent and residual monomer; therefore, slowing-down or inhibition of the polymerization is undesirable, except the interaction with the functionalizing agent.

When selecting a modifying agent, consideration should be given to the mechanism of interaction of functional additives with a pseudo- living polymer, and the selected additives should react with the active sites at the ends of polymer chains. Thus, patent RU249 114 provides modifying agents selected from heterocyclic nitrile compounds; in patent US8268933, the modification is carried out with polyimine compounds; in patent RU2516519, polymers are modified with imide compounds; and in application US 2015329655, there is used a protected oxyme containing cyano groups. However, different modifying agents have different effects on the properties of a polymer, and not each functional group introduced in a polymer reduces hysteresis loss.

Patent US8207275 discloses functionalized polymers and vulcanizates prepared therefrom. According to this patent, the produced functionalized polymers correspond to the formula -R ¹ -a, where π is a polymer chain, R ¹ is a bond or a divalent organic group, and a is a sulfur-containing heterocycle selected from ethylene sulfide, propylene sulfide, tetrahydrothiophene, thiazoline, dihydrothiophene , thiadiazine, thioxanthene, thianthrene, phenoxyethanol , dihydroisothiazole , and thienofuran groups or substituted forms thereof .

A disadvantage of the method is that the use of the above-indicated compounds is characteristic of anionic polymerization. As for polybutadiene rubbers, the method has a number of disadvantages, in particular, a low content of 1, 4-cis-units, resulting in impaired viscoelastic properties, gel formation, low consumer properties (elastic hysteresis properties) .

Application US2014187711 discloses a method for preparing a functionalized polymer, comprising the steps of: (I) polymerizing monomer to form a reactive polymer, and (II) reacting the reactive polymer with an unsaturated heterocycle containing an azolinyl group. The technical result is to reduce hysteresis loss.

However, the use of aluminoxanes as an alkylating agent increases the cost of the final product. In addition, the method provides the use of aluminoxane in toluene, which is totally unacceptable in the case of using aliphatic solvents due to polymer chain transfer to toluene. Toluene accumulates in the aliphatic solvent. The catalyst system according to the invention is unstable and could be used immediately after preparation since its reactivity is inversely proportional to the storage time. This aspect is an essential disadvantage since it leads to instability of the process as a whole.

The method for producing a functionalized polymer from a conjugated diene, disclosed in patent US5844050 is closest in view of the technical essence and the achieved result. According to this method, the polymer resulted from polymerization of a conjugated diene in an organic solvent in the presence of a catalyst system based on lanthanide rare-earth elements is modified using at least one functionalized compound selected from the group consisting of N-substituted aminoketones , N- substituted aminothioketones , N-substituted aminoaldehydes, N- substituted aminothioaldehydes , and compounds having a C(=M)-N< bond in the molecules, wherein M is an oxygen atom or a sulfur atom. The resulting polymer has at least 50% terminal modification, a molecular weight (Mn) of 1.3 to 5, a weight average molecular weight (Mw) of 100,000 to 1,000,000, and a cis- 1,4 -bond content of at least 70%.

However, this method has a number of disadvantages: an increased consumption of an organoaluminum compound in the catalyst complex, resulting in an increased ash content in the polymer; the preparation of the complex takes a long time due to the use of preferably linear carboxylic acids; instability of the catalyst complex and, as a consequence, a necessity to use thereof immediately after the preparation; a low monomer conversion; an increased consumption of the modifying agent, including due to a large amount of the organoaluminum compound. In addition, an increased consumption of several components of the method increases the cost of the final product.

Thus, there is a need to develop a more efficient method for producing modified polydienes that exhibit an improved interaction with fillers during the preparation of rubber mixtures and improved elastic-hysteresis properties.

Disclosure of the invention

The object of the present invention is to reduce the economic cost of the process of producing modified polydienes, to improve polymer- filler interaction in the production of rubber mixtures, and to increase elastic hysteresis properties of polydienes.

The object has been addressed by a developed method for producing modified polydienes by polymerization of a conjugated diene in an organic solvent in the presence of a catalyst system comprising (A) a lanthanide rare-earth element, (B) an organoaluminum compound, (C) a conjugated diene, and (D) a halogen-containing component in a molar ratio of (A) : (B) : (C) : (D) equal to 1: (8-30) : (5-30) : (1.5- 3.0), up to at least 95% conversion of the conjugated diene to produce a living polymer, followed by modification of the terminal groups of the living polymer with at least one modifying agent selected from the group of nitrogen- containing heterocycles .

To control the molecular weight of the polymer, an organoaluminum compound comprising at least one hydrogen atom may be additionally added to the charge, which is a mixture of a conjugated diene monomer and an organic solvent, at a molar ratio of (A) : (B) equal to 1: (3.0-6.0). The sum amount of the total organoaluminum compound used in the synthesis process does not exceed the above-indicated molar ratio of (A) : (B) , i.e. 1: (8-30) .

According to the method of the present invention, the produced modified polydiene has the modification degree of not less than 90% and is characterized by an improved processability at the step of rubber mixing. The rubbers produced from the polymer according to the invention are characterized by increased wear resistance and improved physical and chemical properties, as well as by improved elastic hysteresis properties (rolling resistance, wet-tire traction) .

Lanthanide-based catalyst systems including organoaluminum compounds are commonly used catalysts for polymerization of conjugated dienes (Toube R. Metalorganic Catalyst for Synthesis and Polymerization. Ed. By Kaminsky . Berlin; Heidelberg, New Jork: Springer, Verlag, 1999, p. 531) . Stereospecific polymerization of dienes under the action of the catalyst system based on rare-earth element carboxylates and organoaluminum compounds allows the production of polymers with a high content of 1,4-cis units .

Coordination catalysts initiate polymerization of a monomer according to the mechanism that comprises, before the introduction of the monomer in a growing polymer chain, coordination or complexing of the monomer on the metal - containing active site. One of the most advantageous features of coordination catalysts is their ability to provide a stereochemical control of the polymerization reaction and, thus, the production of stereoregular polymers. Coordination catalysts can be one-, two-, three-, or multicomponent systems. Coordination catalysts can be produced by various methods .

The components of a catalyst are pre-mixed outside the polymerization system in the absence or in the presence of a small amount of a monomer. The resulting catalyst system may be optionally subjected to maturation and after that added to the monomer. These catalyst systems provide the production of 1 , 4 -cis-polydienes that, before deactivation of the active sites, have reactive terminal groups and may be considered as pseudo- living polymers.

In carrying out the invention, the catalyst system may include a lanthanide compound, an alkylating agent, and a halogen-containing compound that comprises one or more labile halogen atoms. The alkylating agent may include one or more organoaluminum compounds that are introduced in the catalyst complex simultaneously or separately. In addition, organoaluminum compounds may be used as regulators of the degree of polymerization in chain transfer to alkylaluminum . Such chains are in a rest state and are not able to attach to a monomer. Chains containing a neodymium atom are active. Chain transfer to a monomer molecule is also possible, and, in such a case, the molecule becomes incapable of further growth and modification.

The ability of the modifying agent to interact with polymer produced on a coordination catalyst system is often unobvious. The reactivity of the polymer depends on some factors: on the number of active sites, competing reactions running in a polymerization mixture, for example, monomer polymerization reactions. In addition, the rate of the reaction between the modifying agent and polymer produced on the coordination catalyst system may be very low, and the modifying agent is not completely reacted with the polymer chain. In experiments it has been found that the use of at least one compound selected from the group of nitrogen- containing heterocycles, as a modifying agent in the catalyst system used in the method according to the invention provides a high rate of modification (within a half hour) and a polydiene with a high degree of modification (not less than 90%) .

The method according to the present invention is carried out in the presence of a catalyst system comprising (A) a lanthanide rare-earth element, (B) an organoaluminum compound, (C) a conjugated diene, and (D) a halogen- containing component in a molar ratio of (A) : (B) : (C) : (D) equal to 1: (8-30): (5-30) .-(1.5-3.0).

The lanthanide rare-earth element is a compound that comprises at least one atom of lanthanum, neodymium, cerium, praseodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, or lutetium. The compounds comprising lanthanide atoms may have various oxidation degrees: 0, +2, +3, and +4.

Trivalent lanthanides with an oxidation degree of +3 are preferred. It is preferable to use neodymium compounds.

Compounds comprising lanthanides include, but are not limited to, carboxylates , organophosphates , organophosphonates , organophosphinates , carbamates, dithiocarbamates , lanthanide xanthogenates , β-diketones, halides, oxyhalides, and alcoholates.

Neodymium carboxylates include neodymium formate, neodymium acetate, neodymium acrylate, neodymium methacrylate, neodymium valerate, neodymium gluconate, neodymium citrate, neodymium fumarate, neodymium lactate, neodymium maleate, neodymium oxalate, neodymium 2- ethylhexanoate , neodymium neodecanoate (brand name neodymium versatate) , neodymium naphthenate , neodymium stearate, neodymium oleate, neodymium benzoate, neodymium picolinate, neodymium dibutyl phosphate, neodymium diphenyl phosphate, neodymium dihexyl phosphate, neodymium diheptyl phosphate, neodymium dioctyl phosphate, neodymium bis- (1- methylheptyl) phosphate, neodymium bis- (2-ethyhexyl) phosphate , neodymium didecyl phosphate , neodymium dodecyl phosphate, neodymium dioctadecyl phosphate, neodymium bis- (n-nonylphenyl) phosphate, neodymium butyl- (2-ethylhexyl) phosphate, neodymium (1-methylphenyl) (2-ethylhexyl) phosphate, and neodymium (2-ethylhexyl) (n-nonylphenyl) phosphate .

Neodymium organophosphonates include neodymium butylphosphonate , neodymium pentylphosphonate , neodymium hexylphosphonate , neodymium heptylphosphonate, neodymium octylphosphonate, neodymium (l-methylheptyl)phosphonate, neodymium (2-ethylhexyl) phosphonate, neodymium decylphosphonate, neodymium dodecylphosphonate, neodymium octadecylphosphonate, neodymium oleylphosphonate , neodymium phenylphosphonate , neodymium (n-nonylphenyl) phosphonate , neodymium butyl (butylphosphonate) , neodymium pentyl (pentylphosphonate) , neodymium hexyl (hexylphosphonate) , neodymium heptyl (heptylphosphonate) , neodymium octyl (octylphosphonate) , neodymium (1-methylheptyl) ( (1- methylheptyl) phosphonate) , neodymium (2-ethylhexyl) ( (2 - ethylhexyl) phosphonate) , neodymium decyl (decylphosphonate) , neodymium dodecyl (dodecylphosphanate) , neodymium octadecyl (octadecylphosphonate) , neodymium oleyl (oleylphosphonate) , neodymium phenyl (phenylphosphonate) , neodymium (n-nonylphenyl) ( (n- nonylphenyl) phosphonate) , neodymium butyl ((2 - ethylhexyl) phosponate) , neodymium (2-ethylhexyl) (butyl phosphonate) , neodymium (1-methylheptyl) ( (2- ethylhexyDphosphonate) , neodymium (2-ethylhexyl) ( (1- methylheptyl) phosphonate) , (2-ethylhexyl) ( (n- nonylphenyl) phosphonate) , and (n-nonylphenyl) ( (2- ethylhexyl) phosphonate) .

Neodymium organophosphinates include neodymium butylphosphinate , neodymium pentylphosphinate , neodymium hexylphosphinate, neodymium heptylphosphinate, neodymium octylphosphinate, neodymium (1-methylheptyl) phosphinate, neodymium (2-ethylhexyl) phosphinate, neodymium decylphosphinate , neodymium dodecylphosphinate , neodymium octadecylphosphinate, neodymium oleylphosphinate, neodymium phenylphosphinate , neodymium (n-nonylphenyl) phosphinate, neodymium dibutylphosphinate , neodymium dipentylphosphinate, neodymium dihexylphosphinate, neodymium diheptylphosphinate, neodymium dioctylphosphinate, neodymium bis- (1- methylheptyl) phosphinate , neodymium bis- (2- ethylhexyl) phosphinate, neodymium didecylphosphinate, neodymium didodecylphosphinate , neodymium dioctadecylphosphinate ; neodymium dioleylphosphinate, neodymium diphenylphosphinate, neodymium bis- (n- nonylphenyl) phosphinate, neodymium butyl (2 - ethylhexyl) phosphinate, neodymium (1-methylheptyl) (2- ethylhexyl) phosphinate, and neodymium (2-ethylhexyl) (n- nonylphenyl ) phosphinate .

Carboxylates of neo-acids are preferred. Neo acids comprise a moiety of trialkylcarboxylic acid (branched a, a' -carboxylic acid). Derivatives of neo acids more soluble in hydrocarbon solvents are alkylated more quickly and more completely to form more active catalyst compounds.

Neodymium carboxylates are preferred, and neodymium neodecanoate is most preferred. The organoaluminum compound used in the catalyst system is selected from trialkylaluminum, triphenylaluminum, or dialkylaluminum hydrids .

Alkylaluminum dihydride is selected from the group including trimethylaluminum, triethylaluminum, tri-n- propylaluminum, tri- iso-propylaluminum, tri-n- butylaluminum, tri-iso-butylaluminum, tri-tert- butylaluminum, triphenylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum, diethylaluminum hydride, di-n-propylaluminum hydride, di-n-butylaluminum hydride, di-iso-butylaluminum hydride, dihexylaluminum hydride, di-iso-hexylaluminum hydride, dioctylaluminum hydride, di-iso-octylaluminum hydride, phenylethylaluminum hydride, phenyl -n-propylaluminum hydride, phenyl -iso- propylaluminum hydride, phenyl -n-butylaluminum hydride, phenyl- iso-butylaluminum hydride, benzylethylaluminum hydride, benzyl -n-butylaluminum hydride, benzyl -iso- butylaluminum hydride, benzyl-iso-propylaluminum hydride, and other similar compounds.

Alkylaluminum or alkylaluminum hydride, or a mixture thereof is preferred.

Triethylaluminum, tri-isobutylaluminum, di- isobutylaluminum hydride, or a mixture thereof is most preferred.

The conjugated dienes used in the catalyst system include 1 , 3 -butadiene , isoprene, 2, 3 -dimethyl -1, 3- butadiene, piperylene, 2 -methyl -3 -ethyl -1, 3 -butadiene, 3- methyl-1, 3-pentadiene, 2 -methyl- 3 -ethyl -1, 3-pentadiene, 3- methyl-1 , 3-pentadiene, 1 , 3 -hexadiene , 2 -methyl- 1 , 3 - hexadiene, 1, 3 -heptadiene , 3 -methyl- 1, 3 -heptadiene , 1,3- octadiene, 3 -butyl -1, 3-octadiene, 3 , 4 -dimethyl- 1, 3- hexadiene, 4 , 5-diethyl-l, 3-octadiene, phenyl- 1 , 3 -butadiene , 2 , 3 -diethyl- 1, 3-butadiene, 2 , 3-di-n-propyl-l, 3-butadiene, and 2 -methyl - 3 - isopropyl -1,3 -butadiene .

1 , 3 -Butadiene and isoprene are most preferred as a conjugated diene.

The halogen- containing compound used in the catalyst system is dimethylaluminum chloride, diethylaluminum chloride, di-iso-butylaluminum chloride, dimethylaluminum bromide, diethylaluminum bromide, di-iso-butylaluminum bromide, dimethylaluminum fluoride, diethylaluminum fluoride, di-iso-butylaluminum fluoride, dimethylaluminum iodide, diethylaluminum iodide, di-iso-butylaluminum iodide, methylaluminum dichloride, ethylaluminum dichloride, methylaluminum dibromide, ethylaluminum dibromide, methylaluminum difluoride, ethylaluminum difluoride, methylaluminum sesquichloride, ethylaluminum sesquichloride, iso-butylaluminum sesquichloride, or trimethyltin chloride, trimethyltin bromide, triethyltin chloride, triethyltin bromide, di- tert-butyltin dichloride, di- tert-butyltin dibromide, dibutyltin dichloride, dibutyltin dibromide, tributyltin chloride, tributyltin bromide, or the like.

Ethylaluminum sesquichloride, ethylaluminum dichloride, or diethylaluminum chloride is preferred as a halogen- containing compound.

According to the invention, the polymerization process is carried out in the presence of the catalyst system in which the molar ratio of components (A) : (B) : (C) : (D) is 1: (8-30) : (5-30) : (1.5-3.0) .

The molar ratio of the components of the catalyst system of (A) : (B) : (C) : (D) = 1: (8-20) : (5-20) : (1.8-2.8) is preferred. The molar ratio of the components of the catalyst system Of (A) : (B) : (C) : (D) = 1 : ( 10 - 15 ) : ( 10 - 15 ) : (2.1-2.5 ) is most preferred.

In one embodiment of the present invention, to control the molecular weight of polymer, an organoaluminum compound comprising at least one hydrogen atom is additionally added to the charge, which is a mixture of a conjugated diene monomer and an organic solvent, at a molar ratio of (A) : (B) equal to 1: (3.0-6.0). In this embodiment of the invention, the sum amount of the total organoaluminum compound used in the synthesis, i.e. the amount of the organoaluminum compound used both in the charge and in the catalyst system, does not exceed a molar ratio of (A) : (B) equal to 1: (8:30) .

The amount of the additionally added organoaluminum compound is 3.5 to 5.0 mol based on the component (A) of the catalyst system.

It is more preferable to feed 4.0 to 4.5 mol of the organoaluminum compound based on component (A) of the catalyst system.

According to the present invention, the living polymer resulted from the polymerization of a conjugated diene is modified in the terminal groups with at least one modifying agent selected from the group of nitrogen-containing heterocycles .

Such heterocycles include N-substituted aminothioaldehydes , N-substituted aminothioketones , N- substituted aminothioaldehydes;

N-substituted aminoketones such as 4-N,N- dimethylaminoacetophenone , 4-N,N-diethylaminoacetophenone,

1, 3 -bis- (diphenylamino) -2-propanone, 1, 7-bis-

(methylethylamino) -4 -heptanone , 4-N,N- dimethylaminobenzophenone , 4 -N, -di-tert- butylaminobenzophenone , 4 -N, N-diphenylaminobenzophenone , 4,4' -bis- (dimethylamino) benzophenone, 4,4' -bis-

(diethylamino) benzophenone, and 4,4 ' -bis- (diphenylamino) - benzophenone; N-substituted aminoaldehydes , for example, 4- N, N-dimethylaminobenzaldehyde , 4-N,N- diphenylaminobenzaldehyde, and 4-N,N- divinylaminobenzaldehyde ; N-substituted lactams, such as N- phenyl β-propiolactam, N-methyl β-propiolactam, N-methyl-2- pyrrolidone, N-phenyl -2 -pyrrolidone, N-tert-butyl-2- pyrrolidone, N-phenyl -5 -methyl-2 -pyrrolidone, N-methyl-2- pyrrolidone, N-phenyl- 2 -piperidine, N-methyl ε -caprolactam, N-phenyl ε -caprolactam, N-methyl ω- laurylolactam, and N- vinyl ω- laurylolactam; and corresponding N-substituted thiolactams and N-substituted cyclic tioureas, such as 1,3- dimethylethylene urea, 1 , 3 -divinylethylene urea, 1,3- diethyl - 2 - imidazolidinone , 1 -methyl - 3 -ethyl- 2 - imidazolidinone, and 1 , 3 -dimethyl -2 - imidazolidinone ; and corresponding N-substituted cyclic thioureas; functionalizing agents that include a thiazoline group, such as 2-methylthio-2-thiazoline, 2-ethylthio-2- thiazoline, 2 -propylthio- 2 -thiazoline, 2-butylthio-2- thiazoline, 2-pentylthio-2-thiazoline, 2-hexylthio-2- thiazoline, 2-heptylthio-2-thiazoline, 2-dodecythio-2- thiazoline, 2-phenylthio-2-thiazoline, 2-benzylthio-2- thiazoline, 2-chloro-2-thiazoline, 2-bromo-2-thiazoline, 2- iodo-2-thiazoline, 2-dimethylamino-2-thiazoline, 2- diethylamino-2-thiazoline, 2-methoxy-2-thiazoline, 2- ethoxy-2-thiazoline, 2- (N- methyl-N-3- trimethoxysilylpropyl) -thiazoline or a mixture thereof; dithiocarbamate compounds, such as diethyldithiocarbamic acid 2-benzothiazole ester, piperidinium pentamethylene dithiocarbamate, pipecoline dithiocarbamate, and the like, preferably 2 -benzothiazolyl - diethyl -dithiocarbamate, or a mixture thereof.

The preferred compounds as a modifying agent of the method according to the invention include N-Methyl-2- pyrrolidone, N-phenyl-2-pyrrolidone, N-tert-butyl-2- pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, 1 , 3 -diethyl-2 imidazolidone, 1, 3-di-n-propyl-2-imidazolidone, 1,3-di-iso- propyl-2-imidazolidone, 2-methyl-2-thiazoline, 2-ethyl-2- thiazoline, 2-n-propyl-2-thiazoline, and 2 -benzothiazolyl - diethyl -dithiocarbamate, or a mixture thereof.

1, 3 -Dimethyl- 2 -imidazolidone, 2-ethyl-2-thiazoline, and 2 -benzothiazolyl -diethyl -dithiocarbamate or mixtures thereof are most preferred as a modifying agent.

The amount of the modifying agent used for the production of a modified polydiene in the method according to the invention may vary from 0.1 to 15 mol per 1 mol of rare-earth element, preferably from 0.25 to 10 mol, and most preferably from 0.5 to 5 mol. An excess of the modifying agent does not enter into reaction with the active site of a polymer chain and remains free in the polymerizate, which leads to extra expenses for purification of the polymer and solvent and, thus, to a higher cost of rubber. Thus, the use of more than 15 mol of the modifying agent per 1 mol of rare-earth element is not expedient.

The method for producing a modified polydiene is carried out in a batch or continuous mode in a hydrocarbon solvent by feeding hydrocarbon charge to a reactor/autoclave, wherein the hydrocarbon charge is a mixture of a conjugated diene monomer and the hydrocarbon solvent pre-mixed with the solvent of a catalyst system consisting of a rare-earth element compound, an organoaluminum compound, the conjugated diene, and a halogen-containing organic compound. The concentration of the monomer in the solvent is as a rule 7 to 12 wt.%, preferably 9 to 10%. The concentration of lower than 7% leads to a reduction in the energy efficiency of the process, and the concentration of more than 12% leads to an increase in the polymerizate viscosity and, as a consequence, to an increased energy consumption for isolation and drying processes.

The conjugated dienes used in the production of modified polydienes include 1, 3 -butadiene, isoprene, 2,3- dimethyl-1, 3 -butadiene, piperylene, 2 -methyl-3 -ethyl-1, 3- butadiene, 3 -methyl- 1, 3 -pentadiene , 2 -methyl-3 -ethyl-1, 3- pentadiene, 3 -methyl-1, 3-pentadiene, 1 , 3 -hexadiene , 2- methyl-1, 3-hexadiene, 1 , 3 -heptadiene, 3 -methyl-1, 3- heptadiene, 1 , 3 -octadiene , 3 -butyl- 1, 3-octadiene, 3,4- dimethy1-1, 3-hexadiene, 4, 5-diethyl-l, 3-octadiene, phenyl- 1, 3 -butadiene, 2 , 3 -diethyl- 1 , 3 -butadiene , 2 , 3 -di-n-propyl- 1, 3 -butadiene, and 2 -methyl-3 -isopropyl-1, 3 -butadiene.

1 , 3 -Butadiene and isoprene are most preferred as a conjugated diene.

The solvent for polymerization is an inert organic solvent that may be an individual compound or a mixture of aliphatic hydrocarbons, in particular, such as butane, pentane, hexane, heptane; alicyclic hydrocarbons, in particular, cyclopentane, cyclohexane ; mono-olefins , such as 1-butene, 2-butene, or a mixture thereof; aromatic hydrocarbons, in particular, such as benzene, toluene, xylene; and halogenated hydrocarbons, in particular, such as methylene chloride, chloroform, carbon tetrachloride, trichloroethylene, perchloroethylene , 1 , 2 -dichloroethane .

The hydrocarbon solvent, which is a mixture of cyclohexane : hexane or cyclohexane : nefras (commercial hexane-heptane fraction of paraffin hydrocarbons of dearomatized gasolines from catalytic reforming with a boiling point of 65 to 75°C) in a ratio of (30-55) ÷ (70-45) , is most preferred as a solvent in the method according to the invention.

The catalyst system (CS) is prepared by adding an organoaluminum compound and a rare-earth element compound to a solution of a conjugated diene in an aliphatic solvent, keeping the prepared mixture for from 2 to 20 hours at temperature of 23±2°C, followed by the addition of a halogen-containing compound at a molar rate of the components of the catalyst complex: (A) a lanthanide rare earth element, (B) an organoaluminum compound, (C) a conjugated diene, and (D) a halogen-containing component, (A) : (B) : (C) : (D) equal to 1: (8-30) : (5-30) : (1.5-3.0) .

The charge and the solution of the catalyst complex are fed to a reactor/autoclave equipped with a mixer and a thermal control system.

In a specific embodiment, an organoaluminum compound comprising at least one hydrogen atom is additionally added to the charge, i.e. to the conjugated diene in an organic solvent, at an amount of 3.0 to 6.0 mol based on 1 mol of rare-earth element, to control the molecular weight of the polymer. The sum amount of the total organoaluminum compound used in the process of synthesis of the organoaluminum compound does not exceed the above-indicated ratio of from 8 to 30 mol.

The preferred molar ratio of (A) : (B) is 1: (3.5-5.0), the ratio of 1: (4.0-4.5) is most preferred.

Polymerization of conjugated dienes is performed until the conversion of dienes reaches 95-99% for from 1.5 to 2 hours. When the above conversion has been reached, a solution of a modifier is added to the polymerizate at a molar ratio of 0.1 to 15 mol of the modifier per 1 mol of rare-earth element. Interaction between the modifier and polymerizate occurs under stirring for from 30 min to 2 hours at a temperature of 62 to 80 °C. The modification is performed at the temperature to which the reaction mixture is heated during the polymerization. There is no need for special heating or cooling of the polymerizate in order to carry out the modification process.

Then, the polymerizate is stopped by softened water or ethyl or isopropyl alcohol and is stabilized with a solution of an antioxidant taken in an amount of 0.2 to 0.4% based on polymer.

The modified polydiene (rubber) produced by the claimed method has a Mooney viscosity value of 37 to 45 Mooney relative units (RU) before the modification and of 41 to 50 Mooney RU after the modification; the polydispersity index of the produced polydienes corresponds to the range of 2.49 to 2.63; and the content of 1,4-cis- units is more than 96 wt . % .

The modified polymers produced by the present method are used in the manufacture of rubber mixtures. Rubber mixtures are prepared according to standard formulations that may comprise, along with polymers, other optional additives well known to a skilled person, for example, such as fillers, activators, vulcanization accelerators, vulcanizing agents, various plastisizers, and other processing additives.

Suitable fillers include, for example, carbon black, oxides of silicon, titanium, zinc, and the like.

Activators and vulcanization accelerators may include, for example, oxides of lead, zinc, and magnesium, acetanilide, stearic acid, sulfenamides , diphenylguanidine , and the like. The vulcanizing agents include, for example, sulfur, organic peroxides, polyhalogen derivatives, alkylphenol- formaldehyde resins, oligoether acrylates, and other unsaturated compounds .

Plastisizers and processing additives include, for example, naphthene oils, stearic and oleic acids, paraffins, rosins, and the others.

The produced rubber mixture is characterized by an increased processability at the step of rubber mixing, an increased wear resistance and improved physical and vechanical properties, as well as by improved elastic hysteresis properties (rolling resistance, wet- tire traction) .

Further, there are disclosed embodiments of the present invention. It will be obvious to a skilled person that the present invention is not limited to only the provided examples, and that the same effect is provided by other embodiments that do not go beyond the essence of the claimed invention.

Embodiments of the invention

Test methods used for estimation of the properties of the polymer produced by the claimed method:

1. The microstructure of polymer chains was determined by IR spectroscopy developed in-house using a multiple frustrated total internal reflection (MFTIR) device with a ZnSe crystal; the IR- spectrum of a sample was registered within a range of 4000 to 600 cm ^"1 with a resolution of 4 cm ^"1 , and a scan-number of 32. The IR- spectrometer was calibrated using industrial reference samples of the microctructure of polydiene, in which the fraction of isomeric units was determined by ¹ H and ¹³ C NMR spectra.

2. The molecular weight characteristics of rubbers were measured by gel -permeation chromatography developed in-house on a Breeze gel-chromatograph (Waters) equipped with a refractometric detector. Samples of the produced polymer (rubber) were dissolved in freshly prepared tetrahydrofuran at a weight concentration of the polymer in the solution of 2 mg/ml; universal calibration was made based on polystyrene references. The calculation was performed by using the Mark-Kuhn-Houwink constant for polydienes (K = 0.000457, a = 0.693). Conditions of determination :

- a system of 4 high resolution columns (300 mm length, 7.8 mm diameter) filled with styragel, HR3 , HR4 , HR5, HR6, allowing the analysis of polymers with a molecular weight of between 500 and 1*10 ⁷ amu;

- solvent: tetrahydrofuran; flow rate: 1 cm ³ /min;

- temperature of the column thermostat and refractometer : 300°C.

3. The content of a residual modifier in polymer was determined by pre-extraction of the modifier with ethyl alcohol, followed by analysis on a chromatograph with a flame ionization detector. The residual modifier was calculated by an in-house reference method.

4. The modification degree of polymer was calculated according to the equation:

X, % = (m _f , g - m _r , g) *100%/m _f , g, wherein

X is a modification degree;

m _f is the weight of a fed modifying agent;

m _r is the weight of a residual modifying agent.

5. Plasto-elastic properties of rubbers (plasticity, elastic recovery, cold flow) were determined according to GOST 19920.17 and GOST 19920.18 on a GT7060SA compression plastometer with a thermostat.

6. The Mooney viscosity was measured according to ASTM D 1646. 7. Vulcanization characteristics of rubber mixtures were determined by using a MDR 2000 device (T = 160 °C, vibration amplitude: 0,50°, vibration frequency: 1.7 Hz, time: 30 min) according to ASTM D 5289.

8. Physical and mechanical properties (PMP) of vulcanizates were measured on a Zwick/Roell z005 tensile testing machine according to ASTM D 412-98.

9. The elastic component of the complex dynamic modulus G' (KPa) to determine the distribution of the filler in rubber mixtures and silanization of the filler was measured on an RPA-2000 rubber process analyzer (Alpha Technologies) at 0.1 Hz and 100°C in a deformation range of from 1 to 450%.

10. Heat build-up and residual deformation after compression of rubber mixtures were measured according to

GOST 20418. The heat build-up was determined by an increase in the temperature of a sample after multiple compressions under certain conditions on an RH-2000 dynamic flexometer. Test conditions: statistical deformation: 10%; dynamic deformation: 25%; dynamic deformation frequency: 30 Hz.

11. Volume loss of rubber mixtures in the Shopper- Schlobach abrasion test, determined by the volume loss of a sample due to the friction between the sample and an abrasive surface, was measured according to GOST 23509 on a device for testing rubber resistance to abrasion-wearing of GIBITRE INSTRUMENTS SRL company.

12. Hysteresis properties of rubber mixtures were analyzed on a NETZSCH DMA 242 E Artemis device. Test conditions: dual cantilever bending: 2x5; sample dimensions: 10.00x6.40x1.60 mm; amplitude: 40 μιτι, frequency: 10 Hz; load: 7 N; range of test temperature: - 40°C to 60°C; rate of temperature rise: 2.50°C/min. The hysteresis properties were also measured on the RPA-2000 evice in the mode of shear deformation at a frequency of 0 Hz, 60° C, and a deformation of 1%.

Abbreviations used in the examples are:

REE - rare-earth element

OAC - organoaluminium compound

NdOct3 - neodymium octanoate

NdVer3 - neodymium versatate

Nd (2-EHex) - neodymium 3-2-ethylhexanoate

NdNp3 - neodymium naphthenate

NdP3 - neodymium tris- [bis- (2 -ethylhexylphosphate) ]

DIBAH - di-iso-butylaluminum hydride

IBAH - iso-butylaluminum hydride

DEAH - diethylaluminum hydride

TIBA - tri- iso-butylaluminum

TEA - tri-ethylaluminum

TMA - tri-methylaluminum

THA - tri-n-hexylaluminum

TOA - tri-n-octylaluminum

EASC - ethylaluminum sesquichloride

DEAC - diethylaluminum chloride

MADC - methylaluminum dichloride

DMAC - dimethylaluminum chloride

IBADC - iso-butylaluminum dichloride

DEAI - dimethylaluminum iodide

TCS - tetrachlorosilane

N-MP - methylpyrrolidone

1,3-DMI - 1 , 3 -dimethylimidozalidinone

2-MT - 2-methylthiazolin

BTDEDTC - 2-benzothiazolyl-diethyl-dithiocarbamate

Example according to the prototype

A catalyst complex (CC) was prepared by adding 1.67 g f 8.6% solution of neodymium versatate in an aliphatic olvent and 40 mL of 0.93 mol/L di-iso-butylaluminum hydride (DIBAH) to a butadiene solution and stirring for 15 minutes. Then, a solution of tri-butylphosphine (TBP) (10 mL, 0.5 mol/L) was added to the CC and stirred for 10 min. A 20L autoclave was filled with 1008 g of butadiene dissolved in 13 L of a cyclohexane/nefras mixture, the prepared solution of the CC, and ethylaluminum sesquichloride (EASC) (3.8 mL, 0.65 mol/L), and heated to 60 °C. The molar ratio of neodymium versatate : TBP : DIBAH : EASC was 1:5:37:2.5. Polymerization was carried out for 3 hours at 60 to 65 °C, and the conversion of butadiene was 84%. 2 kg of the polymerizate was sampled from the apparatus to use them for the analytical control of the molecular weight and plasto-elastic properties of the polymer before modification.

(Diethylamino) benzophenone (DEAB) (8.5 g, 32 mol) dissolved in toluene was fed to the remaining polymerizate. The reaction mixture was kept for 30 min at 65 °C, then the polymerizate was cooled to 25 °C, stabilized with a solution of Irganox 1520L antioxidant, and the polymer was isolated by water- steam degassing and dried on drying rolls at

110°C.

The resulting polymer had a Mooney viscosity value of 37, a polydispersity index of 2.6, and a 1,4 -unit content of 96.4%.

Comparative example. Production of non-modified polybutadiene

A catalyst complex was prepared by mixing a 1.4 mmol solution of Nd versatate in cyclohexane, a 14 mmol solution of TIBA in hexane, and a 14 mmol solution of butadiene in cyclohexane in a cyclohexane/nefras solvent, the resulting mixture was kept for 10 hours at 25°C. Then, a 2.8 mmol solution of DIBAH in hexane and a 3.36 mmol solution of EASC in hexane were added to the complex. The molar ratio of the components :

neodymium versatate: butadiene :TIBA:DIBAH: EASC was 1:10:10:2:2.4.

A 20L autoclave under nitrogen was filed with 13 L of a cyclohexane/nefras solvent, 1002 g of butadiene, and the prepared catalyst complex. A solution of DIBAH was additionally added to the charge before the addition of the catalyst complex, at a molar ratio of DIBAH/Nd versatate of 3.2 : 1 to control the molecular weight of the polymer.

Polymerization was carried out at 60 °C for 2 hours. The conversion of monomer was 96%. Upon the completion of modification, an Irganox 1520L antioxidant was added to the polymerizate, and the polymer was isolated by water- steam degassing and dried on rollers at 110 °C.

The polymer produced using this catalyst system had a Mooney viscosity value of 44, a polydispersity index of 2.6, and a 1,4 -unit content of 96.4%.

Example 1 (according to the invention)

A catalyst complex was prepared by mixing a 1.4 mmol solution of Nd versatate in cyclohexane, a 14 mmol solution of TIBA in hexane, and a 14 mmol solution of butadiene in cyclohexane in a cyclohexane/nefras solvent, the resulting mixture was kept for 10 hours at 25 °C. Then, a 2.8 mmol solution of DIBAH in hexane and a 3.36 mmol solution of EASC in hexane were added to the complex. The molar ratio of the components in the prepared catalyst system:

neodymium versatate: butadiene :TIBA: DIBAH: EASC was 1 : 12 : 10 : 2 : 2.4.

A 20L autoclave under nitrogen was filed with 13 L of a cyclohexane/nefras solvent, 1002 g of butadiene, and the prepared catalyst system. A solution of DIBAH was additionally added to the charge before the addition of the catalyst complex, at a molar ratio of DIBAH/Nd versatate of 3.5:1 to control the molecular weight of the polymer.

Polymerization was carried out at 60°C for 2 hours. The conversion of monomer was 96%. Then, a modifying agent, which was a solution of N-methylpyrrolidone (N-MP) in cyclohexane, was added to the prepared polymerizate at a molar ratio of N-MP/Nd of 0.5. Modification was carried out under continuous stirring at 75 °C for 30 min. Upon the completion of modification, an Irganox 1520L antioxidant was added to the polymerizate, the polymer was isolated by water- steam degassing and dried on drying rolls at 110 °C.

The produced modified polymer had a Mooney viscosity value of 49, a 1,4 -unit content of 96.6%, Mw/Mn of 2.6, and a modification degree of 100%.

Example 2

A catalyst system was prepared according to Example 1, except the use of diethylaluminum chloride (DEAC) instead of EASC, and isoprene instead of butadiene. The molar ratio of the components:

neodymium versatate : isoprene : TIBA: DIBAH : DEAC was

1:13:5:2:2.5. A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 6.0:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, and the molar ratio of N-MP/Nd was 1. The produced modified polymer had a Mooney viscosity value of 46, a 1,4 -unit content of 96.7%, Mw/Mn of 2.7, and a modification degree of 100%.

Example 3

A catalyst system was prepared according to Example 1, except the use of ethylaluminum dichloride (EADC) instead of EASC, and piperylene instead of butadiene. The molar ratio of the components of the catalyst system: neodymium versatate:piperylene:TIBA:DIBAH:EADC was 1:10:8:2:2.1.

A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 5:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, and the molar ratio of N-MP/Nd was 3.3. The produced modified polymer had a Mooney viscosity value of 49, a 1,4- unit content of 96.3%, Mw/Mn of 2.6, and the modification degree of 100%.

Example 4

A catalyst system was prepared by adding neodymium versatate in an aliphatic solvent and di-iso-butylaluminum hydride (DIBAH) to a solution of butadiene and stirring the mixture for 60 min. Then, a solution of EASC was added to the CC and stirred for 10 min. The molar ratio of the components of the catalyst system:

neodymium versatate: butadiene: DIBAH: EASC was

1:6:10:2.4.

Modification was carried out according to Example 1, and the molar ratio of N-MP/Nd was 5. The produced modified polymer had a Mooney viscosity value of 49, a 1,4 -unit content of 96.3%, Mw/Mn of 2.6, and a modification degree of 90%.

Example 5

A catalyst system was prepared according to Example 1, except the use of neodymium 2 -ethylhexanoate instead of neodymium versatate, and dimethylaluminum chloride (DMAC) instead of EASC. The molar ratio of the components:

neodymium 2 -ethylhexanoate : butadiene : TIBA: DIBAH : DMAC was 1:15:5.2:2:2.2. A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 6:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, using 1 , 3 -dimethylimidazolidone (1,3-DMI) instead of N- methylpyrrolidone at a molar ratio of 1,3-DMI/Nd of 0.5. The produced modified polymer had a Mooney viscosity value of 40, a 1,4 -unit content of 96.1%, Mw/Mn of 2.7, and a modification degree of 100%.

Example 6

A catalyst system was prepared according to Example 1, except the use of diethylaluminum chloride (DEAC) instead of EASC, and isoprene instead of butadiene. The molar ratio of the components:

neodymium versatate : isoprene : TIBA: DIBAH : DEAC was

1:10:6:2:2.4.

A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 5.5:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, using 1 , 3 -dimethylimidazolidone (1,3-DMI) instead of N- methylpyrrolidone at a molar ratio of 1,3-DMI/Nd of 1. The produced modified polymer had a Mooney viscosity value of 47, a 1,4 -unit content of 96.6%, Mw/Mn of 2.5, and a modification degree of 100%.

Example 7

A catalyst system was prepared according to Example 1, except the use of ethylaluminum dichloride (EADC) instead of EASC. The molar ratio of the components:

neodymium versatate : butadiene : TIBA: DIBAH : EADC was

1:15:7.5:2:2.2. A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 6:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, using 1 , 3 -dimethylimidazolidone (1,3-DMI) instead of N- methylpyrrolidone at a molar ratio of 1,3-DMI/Nd of 5. The produced modified polymer had a Mooney viscosity value of 40, a 1,4 -unit content of 96.3%, Mw/Mn of 2.6, and a modification degree of 92%.

Example 8

A catalyst system was prepared according to Example 1, except the use of tri-ethylaluminum (TEA) instead of TIBA and diethylaluminum chloride (DEAC) instead of EASC. The molar ratio of the components:

neodymium versatate: butadiene: TEA: DIBAH: DEAC was

1:13:6:2:2.5.

A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 6:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, using 2 -methylthiozoline (2-MT) instead of N- methylpyrrolidone at a molar ratio of 2-MT/Nd of 0.1. The produced modified polymer had a Mooney viscosity value of 48, a 1,4-unit content of 96.6%, Mw/Mn of 2.8, and a modification degree of 100%.

Example 9

A catalyst system was prepared according to Example 1, except the use of tri-ethylaluminum (TEA) instead of TIBA, diethylaluminum chloride (DEAC) instead of EASC, and 1,3- hexadiene instead of butadiene. The molar ratio of the components :

neodymium versatate : 1 , 3 -hexadiene : TEA: DIBAH : DEAC was 1.3:30:8:2:2.3. A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 4.5:1, to control the molecular weight of the polymer.

Modification was carried out according to Example 1, using 2 -methylthiozoline (2-MT) instead of N- methylpyrrolidone at a molar ratio of 2-MT/Nd of 0.25. The produced modified polymer had a Mooney viscosity value of 43, a 1,4-unit content of 96.4%, Mw/Mn of 2.6, and a modification degree of 100%.

Example 10

A catalyst system was prepared according to Example 1, except the use of neodymium naphthenate instead of neodymium versatate, silicon tetrachloride (STC) instead of EASC, and piperylene instead of butadiene. The molar ratio of the components:

neodymium naphthenate: piperylene :TIBA: DIBAH: STC was 1:10:9:2:3.0.

A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 3.9:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, using 2 -methylthiozoline (2-MT) instead of N- methylpyrrolidone at a molar ratio of 2-MT/Nd of 1. The produced modified polymer had a Mooney viscosity value of 47, a 1,4-unit content of 97.4%, Mw/Mn of 2.8, and a modification degree of 100%.

Example 11

A catalyst system was prepared according to Example 4, except the use of neodymium tris- [bis- (2- ethylhexyl) phosphate] instead of neodymium versatate, DEAC instead of EASC, and isoprene instead of butadiene. The molar ratio of the components: neodymium tris- [bis- (2- ethylhexyl ) hosphate] : isoprene: DIBAH :DEAC was 1:15:12:1.6.

Modification was carried out according to Example 1, using 2-benzothiazolyl-diethyl-dithiocarbamate (BTDEDTC) instead of N-methylpyrrolidone at a molar ratio of BTDEDTC/Nd of 0.1. The produced modified polymer had a Mooney viscosity value of 45, a 1,4 -unit content of 97.1%, Mw/Mn of 2.7, and a modification degree of 100%.

Example 12

A catalyst system was prepared according to Example 1, except the use of isobutylaluminum dihydride (IBADH) instead of DIBAH. The molar ratio of the components:

neodymium versatate : butadiene : TIBA: IBADH : EASC was 1:7:10:2:2.4.

A 20L autoclave under nitrogen was filed with 13 L of a cyclohexane/nefras solvent, 951 g of butadiene, 50 g of isoprene, and the prepared catalyst complex. A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 4.5:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, using 2 -benzothiazolyl-diethyl-dithiocarbamate (BTDEDTC) instead of N-methylpyrrolidone at a molar ratio of BTDEDTC/Nd of 0.25. The produced modified polymer had a Mooney viscosity value of 45, a 1,4-unit content of 96.4%, Mw/Mn of 2.6, and a modification degree of 100%.

Example 13

A catalyst system was prepared according to Example 1. The molar ratio of the components :

neodymium versatate : butadiene : TIBA: DIBAH : EADC was

1 : 10 : 10 : 2 : 2.4. A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 3.7:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, using 2-benzothiazolyl-diethyl-dithiocarbamate (BTDEDTC) instead of N-methylpyrrolidone at a molar ratio of BTDEDTC/Nd of 1. The produced modified polymer had a Mooney viscosity value of 48, a 1,4-unit content of 96.7%, Mw/Mn of 2.8, and a modification degree of 100%.

Example 14

A catalyst system was prepared according to Example 1, except the use of diethylaluminum chloride (DEAC) instead of EASC and diethylaluminum hydride (DEAH) instead of DIBAH. The molar ratio of the components:

neodymium versatate : butadiene : TIBA: DIBAH : DEAC was

1:12:8:2:2.5.

A solution of DEAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 5:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1 at a molar ratio of N-MP/Nd of 10. The produced modified polymer had a Mooney viscosity value of 46, a 1,4-unit content of 96.9%, Mw/Mn of 2.6, and a modification degree of 95%.

Example 15

A catalyst system was prepared according to Example 4, except the use of dimethylaluminum chloride (DMAC) instead of EASC and piperylene instead of butadiene. The molar ratio of the components :

neodymium versatate : piperylene : DIBAH : DMAC was

1 : 12 : 15 : 3.

Modification was carried out according to Example 1 at a molar ratio of N-MP/Nd of 16. The produced modified polymer had a Mooney viscosity value of 47, a 1,4 -unit content of 96.7%, Mw/Mn of 2.7, and a modification degree of 88%.

With increasing the molar ratio of MA (modifying agent) /Nd to more than 15, the modification degree decreased to lower than 90%.

Example 16

A catalyst system was prepared according to Example 1, except the use of isobutylaluminum dichloride (IBADC) instead of EASC. The molar ratio of the components:

neodymium versatate : butadiene : TIBA: DIBAH : IBADC was 1:25:6:2:2.6.

A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 6:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, using 2-methylthiozoline (2-MT) instead of N- methylpyrrolidone at a molar ratio of 2-MT/Nd of 8. The produced modified polymer had a Mooney viscosity value of 47, a 1,4 -unit content of 97.1%, Mw/Mn of 2.6, and a modification degree of 93%.

Example 17

A catalyst system was prepared according to Example 1, except the use of diethylaluminum iodide (DEAI) instead of EASC. The molar ratio of the components:

neodymium versatate : butadiene : TIBA: DIBAH : DEAI was 1:10:9:2:1.9.

A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 4:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, using 2-methylthiozoline (2-MT) instead of N- methylpyrrolidone at a molar ratio of 2-MT/Nd of 12. The produced modified polymer had a Mooney viscosity value of 48, a 1,4 -unit content of 96.9%, Mw/Mn of 2.6, and a modification degree of 95%.

Example 18

A catalyst system was prepared according to Example 1, except the use of trimethylylaluminum (TMA) instead of TIBA. The molar ratio of the components:

neodymium versatate: butadiene: TMA :DIBAH:EASC was 1:12:10:2:2.4.

A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 3.7:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, using 1, 3-dimethylimidazolidone (1,3-DMI) instead of N- methylpyrrolidone at a molar ratio of 1,3-DMI/Nd of 8. The produced modified polymer had a Mooney viscosity value of 45, a 1,4 -unit content of 96.6%, Mw/Mn of 2.7, and a modification degree of 90%.

Example 19

A catalyst system was prepared according to Example 1, except the use of trihexylaluminum (THA) instead of TIBA. The molar ratio of the components:

neodymium versatate: butadiene: THA: DIBAH :EASC was 1:10:12:2:2.4.

A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 4.5:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, using 1, 3-dimethylimidazolidone (1,3-DMI) instead of N- methylpyrrolidone at a molar ratio of 1,3-DMI/Nd of 15. The produced modified polymer had a Mooney viscosity value of 47, a 1,4 -unit content of 97.0%, Mw/Mn of 2.7, and a modification degree of 92%. Example 20

A catalyst system was prepared according to Example 1, except the use of trioctylaluminum (TOA) instead of TIBA. The molar ratio of the components:

neodymium versatate: butadiene: TOA :DIBAH:EASC was

1:9:15:2:2.4.

A solution of DIBAH was additionally added to the charge at a molar ratio of DIBAH/Nd versatate of 4.5:1 to control the molecular weight of the polymer.

Modification was carried out according to Example 1, using 2 -benzothiazolyl -diethyl -dithiocarbamate (BTDEDTC) instead of N-methylpyrrolidone at a molar ratio of BTDEDTC/Nd of 5. The produced modified polymer had a Mooney viscosity value of 49, a 1,4-unit content of 96.9%, Mw/Mn of 2.7, and a modification degree of 96%.

Preparation of rubber mixtures

Rubber mixtures are prepared by vulcanization of polymer-based compositions. The choice of a polymer and a composition of a rubber mixture is determined by the purpose, working conditions and technical specification of an article, technology of production, and other parameters.

The technology of rubber production comprises mixing raw rubber with ingredients in specific mixers or roll mills, cutting and tailoring a rubber half -finished product (shape and size depend on further planned use of the produced rubber, in particular, on a planned test method) , and vulcanizing the produced half -finished products in special apparatuses (press machines, autoclaves, shaper- vulcanizers, and the like) .

In the present invention, rubber mixtures were prepared according to modes and formulations set forth in standard ASTM D 3189 (Table 2) . Rubber mixing was carried out in two steps in an internal rubber mixer.

The initial mixing step in the internal mixer was carried out at a temperature allowing reaching discharge conditions and at an angular velocity of 8.0 rad/s. The mixer was charged with half of polymer, the whole zinc oxide, carbon black, oil, and stearic acid, and then with the remaining polymer. The mixture was stirred until a temperature of 170 °C or for the total mixing time of 6 min, whichever was sooner. Then the mixture was discharged and passed over a roll mill at a temperature of 40±5°C and a gap between rolls of 6.0 mm. Then, the mixture was kept for 1-24 hours at room temperature.

The final mixing step in the internal rubber mixer was carried out at a temperature of 40±5°C, disconnecting the steam supply and including the cooling water supply to the rotors, at a velocity of 8.0 rad/s. The whole sulfur and sulfenamide was wrapped to half of a masterbatch (the mixture resulting from the initial mixing step) and loaded to the rubber mixer, and then the remainder of the masterbatch was added.

The mixture was stirred until a temperature of 110±5°C or for the total mixing time of 3 min, whichever was sooner. The mixture was discharged and then passed as a roll over rolls perpendicularly to the surface of the rolls at a gap between rolls of 0.8 mm and a temperature of the surface of the rolls of 40±5°C. After that, the gap was set so as to obtain the thick of the mixture of not less than 6 mm, and the mixture was passed over the rolls, each time folding it double.

Samples, which were sufficient to determine the viscosity of the mixture, its processability according to GOST P 54552, and vulcanization characteristics according to GOST P 54547, were cut from the prepared rubber mixture. To determine stress-strain behavior under tension, test sheets were prepared and vulcanized according to GOST P 54554. The recommended standard vulcanization time for mixtures prepared by methods A, B, and C is 25, 35, and 50 minutes at 145°C. The recommended standard vulcanization time for the mixture prepared in an internal mixer is 35 minutes at 145°C. The vulcanized sheets were conditioned for 16-96 hours at 23±2°C.

Table 1. Process conditions and properties of the produced polydxenes

Table 1. Continuation

Table 2. Composition of rubber mixtures based on the produced modified polydienes

As can be seen from the examples, the modified polydienes produced by the method according to the invention are characterized by a degree of modification of at least 90%, a reduced value of the Payne effect, and, as a consequence, by an improved distribution of filler particles in the rubber matrix.

The rubbers produced from the obtained polydiens are characterized by an increased wear resistance index and reduced elastic-hysteresis values compared to non-modified polydiene. Thus, the use of polymers prepared by the method according to the invention in the manufacture of tires has a positive impact on their performance properties and fuel efficiency .