CN114981316A

CN114981316A - Process for producing branched polydienes

Info

Publication number: CN114981316A
Application number: CN201980103030.6A
Authority: CN
Inventors: 乔治·维克托罗维奇·贾巴罗夫; 阿列克塞伊·弗拉基米罗维奇·特卡乔夫; 塔蒂亚娜·亚历山德罗娃·亚特谢瓦; 斯韦特兰娜·阿莱斯纳·拉格诺娃
Original assignee: Sibur Holding PJSC
Current assignee: Sibur Holding PJSC
Priority date: 2019-12-20
Filing date: 2019-12-20
Publication date: 2022-08-30
Anticipated expiration: 2039-12-20
Also published as: EP4077406A1; KR20220119673A; CN114981316B; WO2021126002A1; EP4077406A4

Abstract

The present invention relates to the production of synthetic rubbers used in the manufacture of tires and tire components, rubber products, golf balls, and other similar products. In particular, the present invention relates to a process for producing a branched polydiene by: polymerizing a conjugated diene in a hydrocarbon solvent medium in the presence of a catalyst system comprising a lanthanide compound, an organosilicon compound, a conjugated diene, and a halogen-containing component; at the end of the polymerization a branching agent is introduced, said branching agent being selected from the group of chlorine-containing compounds or compounds containing at least two maleic acid segments, and the hydrocarbon solvent being furthermore a mixture of an aliphatic solvent (A) and a low-boiling hydrocarbon C5 to C6(B) in percentages by weight (A) to (50 to 90) to (10 to 50). The technical result of the present invention is an increase in the productivity of the polydiene production process, a reduction in the dynamic viscosity of the polymerization solution, an improvement in recyclability, an increase in the branching coefficient of the polymer (characterized by a reduction in the mechanical loss tangent tg δ (1200%), a reduction in cold flow, and an improvement in the plastoelastic properties.

Description

Process for producing branched polydienes

Technical Field

The present invention relates to the production of synthetic rubbers for the manufacture of tires and tire components, rubber products, golf balls and the like. In particular, the present invention relates to a process for producing a branched polydiene by: polymerizing a conjugated diene in a hydrocarbon solvent in the presence of a catalyst system comprising a lanthanide compound, an organoaluminum compound, a conjugated diene, and a halogen-containing component; and introducing a branching agent at the end of the polymerization, the branching agent being selected from chlorine-containing compounds or compounds containing at least two maleic acid segments, wherein the hydrocarbon solvent used in the step of polymerizing the diene is a mixture of an aliphatic solvent (a) and a low-boiling hydrocarbon C5 to C6(B) in weight percent (a): 50 to 90): 10 to 50). Furthermore, the invention relates to a rubber composition comprising the obtained branched polydiene, which is particularly useful for the manufacture of tires and rubber products.

Background

Generally, aromatic hydrocarbons or mixtures thereof with aliphatic hydrocarbons are used as solvents for the polymerization of butadiene. The industry uses mainly benzene, toluene or mixtures thereof with cyclohexane or hexane (Bashkatov T.V., Zhigalin Y.L. synthetic rubber technology: Textbook for technical tools (Russian), 2 nd edition, revision L.: Chemistry, page 1987.360, page 170, [1 ]).

It is known that, in order to ensure a high rate of polymerization of butadiene with The aid of titanium catalyst systems containing iodine, and The production of polybutadiene having The necessary microstructure and molecular parameters, The process must be carried out in an aromatic solvent or a mixture of an aromatic solvent with a small amount of an aliphatic hydrocarbon (Murachev V.B., Aksenov V.I. et al The impact of The composition of a mixed solvent (cellulose-hexane) on The sensitivity of a polybutadienee and activity of a titanium catalyst system (Russian)// M.: TsNIITENEFTEKhim, rukop. Dep. 12 p. -1987.-87RZHH 10S470, [2 ]). An increase in the proportion of aliphatic components leads to a decrease in the yield of the polymer and a deterioration in many other properties of the final product.

Meanwhile, the use of a mixture of an aromatic solvent and an aliphatic solvent helps to reduce the viscosity of the polymerization product, as compared with the viscosity of the polymerization product obtained under the same conditions only in the aromatic solvent.

It is known to prepare ethylene-alpha-olefin copolymers (CN103880999, UNIV ZHEJIANG,06/15/2016, [3]) by solution polymerization method A. According to the known process, the polymerization is carried out using mixed organic solvents, which reduces the viscosity of the polymer system, thus facilitating the separation and purification of the solvent, and therefore the known process is characterized by reduced energy consumption.

In patent RU2523799(CHINA polyethylene & CHEMICAL corp. inc. (CN), BEIJING unity OF CHEMICAL TECHNOLOGY (CN),07.27.2014, [4]), complex additives are used to reduce the viscosity OF the polymer solution. The complex additive consists of a higher carboxylic acid, an alcohol (C1 to C10 alcohol), an ammonium/alkali metal or alkaline earth metal salt (carboxylate, sulfate, sulfonate or phosphate), and in some cases water. The additive is introduced into the polymer solution after polymerization in an amount of 0.7 to 6.0% by weight, based on the total weight of the polymer.

The interaction time of the additive with the polymer solution at 100 ℃ to 110 ℃ is from 0.5 minutes to 30 minutes. The use of this additive reduces the viscosity of the polymer solution by 31% to 85%, depending on the composition of the additive and the type of rubber obtained.

However, the multi-component nature of the additives complicates the hardware design of the process.

In the process described in patent US6177603B1(BRIDGESTONE CORP (US), 23.1.2001, [5]), the viscosity of the polymerization product is reduced by introducing diethylzinc into the reaction mass in the polymerization stage at a molar ratio Zn/Nd of 3.8 to 20. The polymerization is carried out in the presence of a catalyst system comprising neodymium versatate (neodymium neodecanoate) or neodymium tris (2-ethylhexyl) phosphate and dibutylmagnesium. The inventors [5] have shown that the use of diethylzinc as an additive can prevent gel formation and significantly reduce the viscosity of the polymerization product.

However, when diethylzinc is used at a Zn/Nd molar ratio of 3.8 to 20, the yield of polydiene does not exceed 72%.

According to patents RU2510402(LANXESS AG (DE),03/27/2014, [6]) and RU2622648(SAUDI araian OIL COMPANY (SAUDI aranco), 06/19/2017, [7]), processes for polymerization in mixed aliphatic hydrocarbon solvents comprising components having a boiling point below 45 ℃ at a pressure equal to 1013hPa and components having a boiling point in the range of 45 ℃ to 80 ℃, in particular isopentane and cyclopentane, at a pressure equal to 1013hPa, are known. According to the data presented, the viscosity of the polymerization product of the butyl rubber solution is thus reduced and, in addition, the use of these additives can increase the solids content in the solution to 16 to 18% by weight.

In all prior processes, an aromatic solvent is present in the reaction mass, which solvent occupies vacant coordination sites in the complex when polymerized over a lanthanide catalyst system, thereby inhibiting polymerization. Furthermore, in these patents, there is no mention of any change/improvement in the characteristics of the polymer itself in relation to the use of viscosity-reducing additives.

The closest prior art in terms of technical nature and achieved results is the method disclosed in patent US5397851(LANXESS INC. (CA),03/14/1995, [8]) for producing rubber, chosen as the prototype of the invention. According to the data provided in [8], butadiene is polymerized in a mixed hydrocarbon solvent medium comprising hexane, butene-1 and/or benzene over a catalyst system comprising cobalt dioctoate, tributylaluminum and diethylaluminum chloride. The samples obtained are characterized by a high content of 1, 4-cis units (at least 97.4 wt%).

However, in this prior art document, no indication is given of the influence of the composition of the solvent on the viscosity of the polymer solution and the properties of the resulting rubber.

Disclosure of Invention

The invention solves the technical problems of improving the productivity, reducing the viscosity of the polymer solution and reducing the energy consumption when producing the polydiene rubber.

The technical result of the invention is an increased productivity of the polydiene production process, a reduced dynamic viscosity of the polymer solution and consumption rate of branching agent, improved processability, an increased rubber branching coefficient (characterized by a reduction in the mechanical loss tangent tg δ (1200%), and a reduction in the cold flow and an improvement in plasto-elastic properties.

The technical result is realized by carrying out the following method: polymerizing a conjugated diene in a hydrocarbon solvent in the presence of a catalyst system comprising a lanthanide compound, an organoaluminum compound, the conjugated diene, and a halogen-containing component, and introducing a branching agent at the end of the polymerization, said branching agent being selected from the group of chlorine-containing compounds or compounds comprising at least two maleic acid segments, wherein said hydrocarbon solvent is a mixture of an aliphatic solvent (A) and a low boiling hydrocarbon C5 to C6(B) in a weight-wise ratio (A): (50 to 90): (10 to 50).

Detailed Description

The present invention relates to a process for producing a branched polydiene by: polymerizing a conjugated diene in a hydrocarbon solvent in the presence of a catalyst system comprising a lanthanide compound, an organoaluminum compound, the conjugated diene, and a halogen-containing component, introducing a branching agent at the end of the polymerization, the branching agent being selected from the group of chlorine-containing compounds or compounds comprising at least two maleic acid segments, wherein the hydrocarbon solvent is a mixture of an aliphatic solvent (A) and a low boiling hydrocarbon C5 to C6(B) in the weight ratio (A): (B): from 50 to 90): from 10 to 50.

In order to improve the technical characteristics of the rubber based on the polymer obtained, various Branching Agents (BA) are used, thus obtaining the formation of branched polymer molecules. This factor influences properties such as the stacking order of the chain segments relative to each other, the plastoelastic properties, the melt viscosity, etc., which makes it possible to obtain new materials with improved properties.

In the present invention, various chlorine-containing compounds are used as branching agents, such as tin tetrachloride, methyltin trichloride, dimethyltin dichloride, ethyltin trichloride, diethyltin dichloride, n-butyltin trichloride, di-n-butyltin chloride, phenyltin trichloride, tris-tetrachloro (tri-tetrachlororide), diphenyl trichloride 2,4, 6-tris (phenoxy) -1,3, 5-triaza-2, 4, 6-triphosphazene (2,4, 6-tris (phenoxy) -1,3, 5-triaza-2, 4, 6-triphosphazene), hexachlorocyclotriphosphazene (hexachlorocyclotriphosphazene), or mixtures thereof.

Preference is given to using tin tetrachloride, silicon tetrachloride or hexachlorocyclotriphosphazene. Tin tetrachloride is most preferred.

The branching agents are used in the form of 1 to 20% by weight solutions in aliphatic solvents. Solutions of the branching agent are prepared in advance or just prior to use.

The molar ratio of the chlorine-containing branching agent BA to the lanthanides used according to the invention is 0.1:1 to 4: 1. This ratio provides for the production of polydienes having optimum plastoelastic properties with a high content of not less than 97% by weight of units having a mechanical loss tangent tg δ (1200%) not greater than 6.5, 1, 4-cis.

Preferred molar ratios of chlorine-containing BA to lanthanide are in the range of 0.2:1 to 3: 1.

The most preferred molar ratio of chlorine-containing BA to lanthanide is from 1:1 to 2.5: 1.

In another embodiment of the invention, compounds comprising at least two maleic acid segments are used as branching agents. One maleic acid segment gives a lower degree of branching and therefore poorer processability of the rubber composition is noted compared to polymers modified with two or more maleic acid segments. As compounds containing maleic acid segments, maleated polydienes are widely distributed and commercially available, particularly maleated polybutadiene rubber and maleated polyisoprene rubber, and in one embodiment maleated polybutadiene low molecular weight rubber and maleated polyisoprene low molecular weight rubber.

The molar ratio of branching agent comprising at least two maleic acid segments to neodymium used according to the invention is from 0.1:1 to 5: 1. Said ratio allows to obtain polydienes having optimum plastoelastic properties with a high content of units of not more than 6.5, 1, 4-cis and not less than 97% by weight of mechanical loss tangent tg δ (1200%).

The preferred molar ratio of maleated BA to neodymium is from 0.5:1 to 2: 1.

Most preferably, the molar ratio of maleated BA to neodymium is from 0.8:1 to 1.0: 1.

Increasing the molar amount of branching agent above the ranges provided results in a significant difference in mooney viscosities, which adversely affects the plastoelastic properties, with problems with the selection of the polymer and its processing. It is not effective to reduce the molar amount of branching agent below the specified range.

According to the claimed process for the polymerization of conjugated dienes, the calculated fraction of the aliphatic solvent (a) is replaced by low boiling hydrocarbons C5 to C6(B) having boiling points in the range of 25 ℃ to 65 ℃, preferably 35 ℃ to 60 ℃, most preferably 40 ℃ to 50 ℃ at atmospheric pressure. As such hydrocarbons (B), aliphatic hydrocarbons are used, alone or in mixtures with one another, such as, in particular, pentane, isopentane, hexane, 2-methylpentane (isohexane), 3-methylpentane, 2-dimethylbutane (neohexane), 2, 3-dimethylbutane; and/or an alicyclic hydrocarbon selected from cyclopentane, methylcyclobutane, ethylcyclopropane.

Preferably, isopentane, cyclopentane, hexane are used as the low boiling hydrocarbon (B), most preferably cyclopentane, hexane or a mixture thereof.

The authors of the present invention found that the use of hydrocarbons with boiling points below 25 ℃ is undesirable, since higher pressures would have to be used to keep the system in the liquid state. The use of hydrocarbons with boiling points above 65 c will result in reduced manufacturability of the rubber separation during the degassing stage.

According to the invention, the proportion of the low-boiling hydrocarbons (B) is from 7 to 50% by weight, preferably from 9 to 20% by weight, most preferably from 10 to 15% by weight, based on the total weight of the solvent. The authors of the present invention found that when the content of low boiling hydrocarbons is less than 7% by weight, the viscosity drop of the polymer solution will be too slight and the presence of low boiling C5 to C6 hydrocarbons will not affect the properties of the final rubber. The content of the low-boiling hydrocarbons C5 to C6 of more than 50% by weight in the total solvent volume leads to a drastic increase in the pressure in the reactor owing to the low boiling points of these hydrocarbons and, in addition, to an accelerated formation of high molecular weight polymer deposits on the inner surfaces of the apparatus.

The aliphatic solvent (a) used for the polymerization is an inert organic solvent, which is selected, for example, from: heptane, nefras; and cycloaliphatic solvents, such as cyclohexane, cycloheptane, or mixtures thereof, among others.

In the context of the present invention nefras is a hexane-heptane fraction of the paraffins of the dearomatised catalytically reformed gasoline having a boiling point of from 65 ℃ to 75 ℃.

Preferably, cyclohexane or a mixture of cyclohexane and nefras is used as aliphatic solvent.

Most preferably, a mixture of cyclohexane and nefras in a weight ratio of 65:35 to 70:30, respectively, is used as aliphatic solvent.

The authors of the present invention have found that the use of low boiling hydrocarbons as additives reduces the final viscosity of polydiene solutions by 16% to 51% due to the lower viscosity of the low boiling hydrocarbons C5 to C6 compared to the viscosity of other aliphatic solvents, which in turn increases the monomer content in the reaction mixture, thereby increasing the productivity of the polymer production process. Furthermore, it was surprisingly found that the presence of low boiling C5 to C6 hydrocarbons in the polymerization solvent significantly improved the efficiency of using the Branching Agent (BA) and also reduced the mechanical loss tangent tg δ (1200%) by 3% to 25%, indicating that the use of less branching agent produced more branched polymers characterized by good processability and plastoelastic properties.

Since the branching degree of the polydiene rubber increases with decreasing mechanical loss tangent tg δ (1200%) and increasing low boiling hydrocarbon content, the most preferable component weight ratio in the mixed solvent of the aliphatic solvent (a) and the low boiling hydrocarbon (B) is 90:10 in order to achieve the best polymer characteristics and the best processability for production thereof.

The process for producing diene copolymers according to the invention comprises several steps, in particular: preparing a catalyst system, polymerizing a diene using the above system, introducing a branching agent after a conversion of the diene of not less than 96%, modifying the polymer, terminating, degassing, separating and drying.

According to the invention, a catalyst system is used comprising a lanthanide compound, an organoaluminum compound, and a halogen-containing component. As the lanthanide compound, a compound containing at least one lanthanide atom selected from the group consisting of: neodymium, lanthanum, cerium, praseodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Neodymium compounds are preferably used.

Compounds containing a lanthanide element include, but are not limited to, compounds such as the following: carboxylates, organophosphates (especially alkyl phosphates and aryl phosphates), organophosphonates (especially alkyl phosphonates and aryl phosphonates), organophosphinates (especially alkyl phosphinates and aryl phosphinates), carbamates, dithiocarbamates, lanthanide dithiocarbonates, beta-diketonates, halides, oxyhalides, and alcoholates.

Neodymium carboxylates include neodymium formate, neodymium acetate, neodymium acrylate, neodymium methacrylate, neodymium valerate, neodymium gluconate, neodymium citrate, neodymium fumarate, neodymium maleate, neodymium oxalate, neodymium 2-ethylhexanoate, neodymium neodecanoate, neodymium naphthenate, neodymium stearate, neodymium oleate, neodymium benzoate, and neodymium picolinate.

Neodymium organophosphates include neodymium dibutyl phosphate, neodymium diphenyl phosphate, neodymium dihexyl phosphate, neodymium diheptyl phosphate, neodymium dioctyl phosphate, neodymium bis- (1-methylheptyl) phosphate, neodymium bis- (2-ethylhexyl) phosphate, neodymium didecyl phosphate, neodymium didodecyl 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 organophosphates include neodymium butylphosphonate, neodymium pentylphosphonate, neodymium hexylphosphonate, neodymium heptylphosphonate, neodymium octylphosphonate, neodymium (1-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 (dodecylphosphonate), neodymium octadecyl (octadecylphosphonate), neodymium oleylphosphonate (oleylphosphonate), Neodymium phenyl (phenylphosphonate), neodymium n-nonylphenyl (n-nonylphenyl) phosphonate, neodymium butyl ((2-ethylhexyl) phosphonate), neodymium 2-ethylhexyl (butylphosphonate), neodymium 1-methylheptyl) ((2-ethylhexyl) phosphonate), neodymium 2-ethylhexyl) ((1-methylheptyl) phosphonate), neodymium 2-ethylhexyl) ((n-nonylphenyl) phosphonate), and neodymium (p-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 decyphosphinate, neodymium dodecylphosphinate, neodymium octadecylphosphinate, neodymium oleylphosphinate, neodymium phenylphosphinate, (neodymium n-nonylphenyl) phosphinate, neodymium dibutylphosphinate, neodymium dipentyphosphinate, neodymium dihexylphosphinate, neodymium diheptylphosphinate, neodymium dioctylphosphinate, neodymium bis- (1-methylheptyl) phosphinate, neodymium bis- (2-ethylhexyl) phosphinate, neodymium tris- [ bis- (2-ethylhexyl) phosphinate ] neodymium, 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.

Most preferred is the use of carboxylic acid salts of neo acids (neo acids) because their alkylation is faster and more complete, which makes the catalyst compounds more active.

Most preferably neodymium neodecanoate, neodymium tris- [ bis- (2-ethylhexyl) phosphate ] or mixtures thereof are used.

According to the present invention, as the organoaluminum compound, the following compounds can be used: trialkylaluminum, triphenylaluminum or dialkylaluminum hydride, alkylaluminum hydrides, particularly trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-tert-butylaluminum (tritetbutilalum), triphenylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum, diethylaluminum hydride, di-n-propylaluminum hydride, di-n-butylaluminum hydride, diisobutylaluminum hydride, dihexylaluminum hydride, diisohexylaluminum hydride, dioctylaluminum hydride, diisooctylaluminum hydride (diisoakylluminum hydride), phenylethylaluminum hydride, phenyl-n-propylaluminum hydride, phenylisopropylaluminum hydride, phenyl-n-butylaluminum hydride, phenylisobutylaluminum hydride, benzylethylaluminum hydride, benzyl-n-butylaluminum hydride, benzylisobutylaluminum hydride, benzylisopropylaluminum hydride, and the like.

Preference is given to using aluminum alkyls or aluminum alkyl hydrides or mixtures thereof. Most preferably, triethylaluminum, triisobutylaluminum, diisobutylaluminum hydride or mixtures thereof are used.

As the conjugated diene in the process according to the invention, 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, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, isoprene, butadiene, 4, 5-diethyl-1, 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.

Most preferably, 1, 3-butadiene and isoprene are used as conjugated dienes.

As the halogen-containing component, an organohaloaluminum compound (organohalogen aluminum compound) may be used, and specifically, for example, dimethylaluminum chloride, diethylaluminum chloride, diisobutylaluminum chloride, dimethylaluminum bromide, diethylaluminum bromide, diisobutylaluminum bromide, dimethylaluminum fluoride, diethylaluminum fluoride, diisobutylaluminum fluoride, dimethylaluminum iodide, diethylaluminum iodide, diisobutylaluminum iodide, methylaluminum dichloride, ethylaluminum dichloride, methylaluminum dibromide, ethylaluminum dibromide, methylaluminum difluoride, ethylaluminum difluoride, methylaluminum sesquichloride, ethylaluminum sesquichloride, isobutylaluminum sesquichloride, or a mixture thereof.

Preferably, ethyl aluminum sesquichloride is used as the halogen-containing component.

According to the invention, for carrying out the polymerization, a catalyst system is used which comprises: (i) a lanthanide compound, (ii) a conjugated diene, (iii) an organoaluminum compound, and (iv) a halogen-containing component in a molar ratio of (i) to (ii) to (iii) to (iv) equal to 1 (5 to 30) to (8 to 30) to (1.5 to 4.5).

Preferred molar ratios of the catalyst system components (i): (ii): (iii): iv): 1, (5 to 20): (8 to 20): 1.8 to 4.0.

The most preferred molar ratios of the catalyst system components (i): (ii): (iii): iv) ═ 1 (10 to 15): (2.1 to 3.5).

According to one embodiment of the invention, the above catalyst system is used to produce branched polydienes by polymerizing conjugated dienes in a mixed hydrocarbon solvent medium.

According to the present invention, a mixed solvent for polymerization is prepared by: predetermined amounts of an aliphatic solvent and a low boiling point hydrocarbon are mixed at room temperature in air or under a nitrogen atmosphere, and then nitrogen is bubbled through the resulting solvent for at least 30 minutes. Mixed solvents can be used both in the polymerization stage and in the preparation of the catalyst system.

The diene copolymer is prepared in a batch or continuous manner in a hydrocarbon solvent medium by charging the prepared solvent to a polymerization vessel (reactor or autoclave), wherein the solvent comprises a low boiling hydrocarbon monomer, and a catalyst system consisting of a lanthanide compound, a conjugated diene, an organoaluminum compound, and a halogen-containing organic component, premixed with the solvent. The concentration of the monomer in the solvent is usually 7 to 15% by weight, preferably 11 to 13% by weight. Concentrations below 7% by weight lead to a reduction in the energy efficiency of the process, and concentrations above 13% by weight lead to an increase in the viscosity of the polymerization product and, consequently, an increase in the energy consumption during the isolation and drying of the rubber.

The catalyst system was prepared by: in the following molar ratios of the components of the catalyst system: (i) a lanthanide compound, (ii) a conjugated diene (iii) an organoaluminum compound and (iv) a halogen-containing component (i), (ii), (iii), (iv) equal to 1 (5 to 30), (8 to 30), (1,5 to 3,0), introducing the organoaluminum compound (most preferably triisobutylaluminum, triethylaluminum, diisobutylaluminum hydride or a mixture thereof), the lanthanide compound (most preferably a carboxylate of neodymium, particularly neodecanoate) into a solution of the conjugated diene (most preferably 1, 3-butadiene) in an aliphatic solvent (most preferably in a mixture of nefras/cyclohexane or in a mixture of cyclohexane/n-hexane), holding the resulting mixture at a temperature of 23 + -2 ℃ for 2 to 20 hours, and then adding the halogen-containing component (most preferably ethylaluminum sesquichloride, ethylaluminum dichloride), Diethyl aluminum chloride or mixtures thereof).

The duration of the polymerization is from 0.5 to 3 hours. The monomer conversion rate reaches 96 to 99 percent.

Upon reaching the above conversion, a branching agent is introduced into the polymer. Further, the resulting mixture is thoroughly mixed at a temperature of 60 ℃ to 90 ℃ for 15 minutes to 6 hours. The mixing time and thus the modification time is preferably from 15 minutes to 5 hours, most preferably from 20 minutes to 2 hours. At temperatures below 60 ℃, the viscosity of the polymer will increase, which is undesirable because of difficulties in the isolation of the polymer and its processing. At the same time, the end groups of the polymer chain tend to lose their activity at temperatures above 90 ℃, resulting in a reduced degree of modification of the polymer.

At the end of the modification process, the polymer product is terminated with demineralized water or ethanol or isopropanol and stabilized with an antioxidant solution in an amount of 0.2 to 0.6% by weight. Furthermore, the separation of the rubber is carried out by known methods, such as water-vapor degassing and drying on a roll.

The branched polydiene obtained by the above method has a mooney viscosity index after modification of 39 to 52 mooney regular units, the polydispersity index of the obtained diene copolymer corresponds to a range of 2.4 to 2.8, the content of 1, 4-cis units is more than 97% by weight, the mechanical loss tangent tg δ (1200%) is in a range of 6.41 to 2.87, the plasticity is 0.41 to 0.56, the cold flow is 17.4 mm/hr to 35.8 mm/hr, and the elastic recovery is 0.99mm to 2.17 mm.

The invention also relates to rubber compositions based on the polydienes obtained by this process, and such compositions for the manufacture of tires and rubber products. The mixture of the components of the rubber composition is determined by the purpose of the product, the operating conditions and technical requirements, the production technology and other aspects.

The process of rubber production comprises mixing the rubber with the raw materials in a special mixer or on a mill, cutting and trimming the semifinished product from the rubber (shape and dimensions depending on the planned further use of the obtained rubber, in particular depending on the planned test method) and vulcanizing the obtained semifinished product in a special apparatus (press, autoclave, setting vulcanizer, etc.).

The rubber composition is based on the polydiene obtained, which is prepared according to standard formulations (e.g. according to ASTM 3189).

Examples of the practice of the invention

Examples of the practice of the invention are described below. It should be clear that the invention is not limited to the examples provided and that the same effects can be achieved in other embodiments without exceeding the essence of the claimed invention.

A test method for evaluating the properties of the polymers obtained by the claimed method is described.

1. The conversion was determined by precipitating the polymer from the polymerization product with ethanol and drying the isolated polymer.

2. Microstructure of polymer chains using a removable device with Multiple Attenuated Total Internal Reflection (MATIR) of diamond crystals or using a front portion of single Attenuated Total Internal Reflection (ATIR) with ZnSe crystals(prefix) was determined by IR spectroscopy according to ISO 12965 at 4000cm ^-1 To 400cm ^-1 Recording the IR spectrum of the sample in a range of 2cm resolution ^-1 The number of scans was 32.

3. The molecular weight properties of the rubber were determined by gel permeation chromatography using the internal technique of the gel chromatography system "Breeze" of the company "Waters" with a refraction detector. Rubber samples were dissolved in freshly distilled tetrahydrofuran at a polymer weight concentration of 2mg/ml in solution and calculated using the universal calibration for polystyrene standards and Mark-Kuhn-Hauwink constants for polybutadiene (K. 0.000457, α. 0.693). Determining conditions:

a group of 4 high resolution columns (300mm long, 7.8mm diameter) packed with styrogel HR3, HR4, HR5, HR6, allowing analysis of molecular weights from 500AU to 1 x 10 ⁷ A polymer of AU;

solvent tetrahydrofuran, flow 1cm ³ Per minute;

the temperature of the thermostatic column and refractometer was 30 ℃.

4. Determination of the mechanical loss tangent (tg δ (1200%)) was performed on the device RPA-2000 of the company "Alpha Technologies" with variable shear amplitude: amplitude ranged from 0 to 1200%, frequency 0.1Hz, temperature 100 ℃.

5. The viscosity of the polymerization product solution was determined according to GOST 25271-93 using a Brookfield DV2T viscometer.

6. The determination of the elastoplastic properties (plasticity, cold flow) of the rubber is carried out according to the national standards GOST 19920.17 and GOST 19920.18 on a compression plastometer model GT7060SA with a thermostat.

7. The mooney viscosity index was determined by ASTM D1646.

8. Allows the estimation of the filler distribution in the rubber blend and the elastic component of the silanized complex dynamic shear modulus G' (kPa) of the filler to be determined on an RPA-2000 rubber recyclability analyzer of "Alpha Technologies" at 0.1Hz and 100 ℃ in the deformation range of 1% to 450%. The difference in the cumulative modulus at the deformation amplitudes of 1% and 50% — ag ' (G ' 1% -G ' 43%) — payne effect.

9. The wear resistance when sliding on a recoverable surface was evaluated according to GOST 23509 (method B) on a wear test "gibere Instruments".

Example 1 (according to the closest prior art)

A mixture of diethyl aluminum chloride and tributyl aluminum was prepared by mixing a 1 molar hexane solution of diethyl aluminum chloride (80ml, 0.08mol) with 25 wt% tributyl amine in heptane (15,87g, 0.02mol) under a nitrogen atmosphere.

For polymerization in a glass reactor, which is a 1 liter bottle, 150.0g of cyclohexane, 84.0g of 1-butene, 0.24ml (1.22mmol) of water, 4.0ml of 1.5-octadiene and 72.0g (1.33mol) of 1, 3-butadiene (butadiene content 23% by weight based on the total weight of the solution) were loaded, and the mixture was stirred by shaking in a water bath at 20 ℃ for 10 minutes. Thereafter, a mixture of diethylaluminum chloride and tributylaluminum (3.5mmol) was added to the solution, and the resulting solution was stirred in a water bath at 20 ℃ for 10 minutes. Then, 0.22ml (0.0067mol) of a 0.87% by weight cobalt dioctoate solution in hexane was added. The polymerization was carried out at 20 ℃ for 30 minutes, after which a mixture of water and methanol was added to deactivate the catalyst and precipitate the polybutadiene. Next, the polymer was dried in a vacuum oven at 60 ℃ for 24 hours.

The characteristics of the resulting polymer are presented in table 1.

Example 2 (comparative)

In the first stage, a catalyst system of neodymium neodecanoate-Butadiene (BD) -diisobutylaluminum hydride (DIBAH) -ethylaluminum sesquichloride (EASC) was obtained in a molar ratio of 1:10:13:2.5 (by mass). The curing (ageing) time of the system was 22 hours at a temperature of 23 ℃.

In a 150ml Schlenk vessel, 0.87g (0.522mmol) of neodymium neodecanoate in the form of a 8.7% strength solution in hexane, 40ml of an aliphatic solvent were placed and stirred on a magnetic stirrer at a temperature of 23 ℃ for 10 minutes. Then 0.28g of Butadiene (BD), corresponding to 5.2mmol of butadiene, was introduced into the vessel in the form of a solution having a concentration of 17.8% by weight. The molar ratio of butadiene/Nd was 10.

After stirring the contents at 23 ℃ for 15 minutes, 6.3ml of a 1.07mol/l DIBAH solution were added and the mixture was stirred for 30 minutes. The DIBAH/Nd molar ratio is equal to 13. In addition, 2.0ml of an EASC solution having a concentration of 0.66mol/l, with a Cl/Nd-2.5 molar ratio, was added to the mixture. The solvent was then introduced into the system to a volume of 100ml solution, stirred for 10 minutes and left at 20 ℃ to 23 ℃ for 22 hours to form.

The polymerization was carried out in a 5L reactor equipped with a stirring device and a jacket for heat removal. As medium, a solvent (A) was used which was a mixture of cyclohexane/nefras in a weight ratio of 73: 27. The monomer content in the reaction mass was 11.5 wt.%. The polymerization temperature was 90 ℃. The duration of the process was 2 hours.

The branching agent tin tetrachloride in solution at a concentration of 0.91mol/l was then added to the reactor at a ratio of 2.5mol to 1mol Nd. Stirring was continued for 30 minutes at a temperature of 75 ℃ to carry out the modification process, after which the antioxidant was introduced (weight fraction from 0.2% to 0.4%). The resulting polymer was degassed and dried on a mill and the physical and mechanical parameters as well as the molecular weight characteristics were determined (see table No. 1).

The characteristics of the resulting polymer are shown in table 1. The samples were also tested according to the formulation ASTM 3189 (table 2) for the rubber compositions and the test results are presented in table 3.

Example 3 (according to the invention)

In the first stage, a catalyst system of neodymium neodecanoate-Butadiene (BD) -diisobutylaluminum hydride (DIBAH) -Ethyl Aluminum Sesquichloride (EASC) in a molar ratio of 1:10:13:2.5 (by mass) was obtained. The compound was aged at 23 ℃ for 22 hours.

The reaction was carried out in a 150ml Schlenk vessel, 0.87g (0.522mmol) of neodymium neodecanoate in solution in hexane, having a concentration of 8.7%, were placed in the vessel, a further 40ml of solvent (A) were added and stirring was carried out on a magnetic stirrer at a temperature of 23 ℃ for 10 minutes. 0.28g of Butadiene (BD) corresponding to 5.2mmol of butadiene was then introduced into the vessel as a 17.8% strength by weight solution. The molar ratio of butadiene/Nd was 10.

After stirring the mixture at 23 ℃ for 15 minutes, 6.3ml of a 1.07mol/l DIBAH solution were added and the mixture was stirred for 30 minutes. DIBAH/Nd molar ratio is 13. In addition, 2.0ml of EASC solution with a concentration of 0.66mol/l, molar ratio Cl/Nd 2.5 was administered. The solvent was then introduced into the system to a volume of 100ml solution, stirred for 10 minutes and left at 20 ℃ to 23 ℃ for 22 hours to form.

The polymerization was carried out in a 5L reactor equipped with a stirring device and a jacket for heat removal. As a medium, a mixed solvent obtained by mixing 1702g of the solvent (a), which is a mixture of cyclohexane/nefras in a weight ratio of 73:27, with 434g of the solvent (B), which is isopentane, was used, and thus the solvent (B) in the polymerization solvent was 10% by weight. The monomer content in the reaction mass was 11% by weight. The polymerization temperature was 90 ℃. The duration of the process was 1 hour.

The branching agent tin tetrachloride was then introduced into the reactor in an amount of 2.5mol relative to Nd, in the form of a solution in hexane having a concentration of 0.93 mol/l. Stirring was continued for 30 minutes at a temperature of 75 ℃ to carry out the modification process, after which the antioxidant (weight fraction 0.2% to 0.4%) was introduced. The resulting polymer was degassed and dried on a mill, and the physical and mechanical parameters as well as the molecular weight characteristics were determined.

The characteristics of the resulting polymer are presented in table 1.

Example 4

Similar to example 3, except that the solvent content (B) in the polymerization solvent was 20% by weight.

The characteristics of the resulting polymer are presented in table 1. The samples were also tested according to the formulation ASTM 3189 (table 2) for the rubber compositions and the test results are presented in table 3.

Example 5

Similar to example 3, except that isoprene was used as the monomer, its content in the reaction mass was 13.0 wt.%, and SnCl ₄ The molar ratio with Nd was 0.2.

The characteristics of the resulting polymer are shown in table 1.

Example 6

Similar to example 5, except that the content of the solvent (B) in the polymerization solvent was 20% by weight.

Example 7

Similar to example 3, except that cyclopentane was used as solvent (B).

The characteristics of the resulting polymer are shown in table 1.

Example 8

Similar to example 7, except that the content of the solvent (B) in the polymerization solvent was 20% by weight, and SnCl ₄ The molar ratio to Nd was 0.1.

The characteristics of the resulting polymer are shown in table 1.

Example 9

Similar to example 7, except that the content of the solvent (B) in the polymerization solvent was 15% by weight.

The characteristics of the resulting polymer are shown in table 1.

Example 10

Analogously to example 7, except that isoprene was used as monomer and SiCl was used in the form of a solution in hexane having a concentration of 0.83mol/l in an amount of 2.5mol relative to Nd ₄ As a branching agent.

The characteristics of the resulting polymer are shown in table 1. The samples were also tested according to the rubber composition formulation ASTM 3189 (table 2) and the test results are presented in table 3.

Example 11

Analogously to example 10, except that 2,2,4,4,6, 6-hexachloro-1, 3, 5-triaza-2, 4, 6-triphosphatene was used as branching agent in an amount of 1.5mol relative to Nd, in a solution in toluene at a concentration of 0.5 mol/l.

The characteristics of the resulting polymer are shown in table 1. The samples were also tested according to the rubber compound formulation ASTM 3189 (table 2) and the test results are presented in table 3.

Example 12

Analogously to example 7, except that as branching agent a Maleinised Polybutadiene (MPB) having a maleic anhydride content of 8% and a molecular weight of 2700g/mol was used. The molar ratio of maleic acid groups to neodymium was 0.8.

The characteristics of the resulting polymer are shown in table 1.

Example 13

Similar to example 10, except that as the lanthanide-containing compound, tris- [ bis- (2-ethylhexyl) phosphoric acid was used]Neodymium Isopentane was chosen as solvent, the content of low-boiling hydrocarbons in solvent (B) was 20%, and SnCl was used as branching agent as a solution in hexane with a concentration of 0.9mol/l in a molar amount of 2.0% with respect to Nd ₄ 。

Example 14

Analogously to example 7, with the difference that as compound comprising a lanthanide, neodymium tris- [ bis- (2-ethylhexyl) phosphate ] is used.

The characteristics of the resulting polymer are shown in table 1.

Example 15

Similar to example 3, except that cyclohexane was used as the solvent (A) and n-hexane was used as the solvent (B), the content of n-hexane in the total volume of the polymerization solvents was 20% by weight.

Example 16

Similar to example 15, except that the content of the solvent (B) in the polymerization solvent was 30% by weight.

The characteristics of the resulting polymer are shown in table 1.

Example 17

Similar to example 15, except that the content of the solvent (B) in the polymerization solvent was 50% by weight, the content of the monomer was 11.6% by weight.

The characteristics of the resulting polymer are shown in table 1.

Example 18

Similar to example 15, except that the content of the solvent (B) in the polymerization solvent was 50% by weight, the content of the monomer was 13% by weight.

The characteristics of the resulting polymer are shown in table 1.

Example 19

Similar to example 14, except that cyclohexane was used as the solvent (A) and n-hexane was used as the solvent (B), the weight percentage of (A) to (B) was 80: 20. As branching agent, 2,4, 6-trichloro-2, 4, 6-triphenoxycyclotriphosphazene was used as a solution in nefras at a concentration of 0.5mol/l, the amount used being 1.0mol relative to Nd.

The characteristics of the resulting polymer are shown in table 1.

Example 20

Similar to example 3, except gadolinium versatate (GdV) ₃ ) As lanthanide compound, isoprene was used as monomer, and 2,4, 6-trichloro-2, 4, 6-triphenoxycyclotriphosphazene was used as branching agent in the form of a solution in nefras at a concentration of 0.5 mol/l. The molar ratio of branching agent to Gd is equal to 1.5.

The characteristics of the resulting polymer are shown in table 1.

Example 21

Analogously to example 19, the procedure was followed, characterized in that tin tetrachloride was used as the branching agent in an amount of 3.0mol relative to Nd, in the form of a solution with a concentration of 0.91 mol/l. The monomer content was 13% by weight.

The characteristics of the resulting polymer are shown in table 1.

Example 22

Similar to example 15, except that GdV was used ₃ The lanthanide compound had a molar ratio of tin tetrachloride to Gd of 4.0.

The characteristics of the resulting polymer are shown in table 1.

Example 23

Analogously to example 12, except that as branching agent a Maleated Polyisoprene (MPI) having a maleic anhydride content of 10% and a molecular weight of 30000g/mol was used. The molar ratio of maleic acid groups to neodymium was 0.1.

The characteristics of the resulting polymer are shown in table 1.

Example 24

Similar to example 12, except that the molar ratio of maleic acid groups to neodymium was equal to 5.

The characteristics of the resulting polymer are shown in table 1.

The rubber samples obtained in examples 4,6, 13, 10, 11, 15 were tested with the formulation ASTM 3189 for the rubber compositions (see Table 2). The test results are shown in table 3.

TABLE 1

Preparation and characterization of the copolymers

TABLE 1 continuation

TABLE 1 continuation

TABLE 1 continuation

List of abbreviations in table 1:

a BA-branching agent;

BD-butadiene;

NdP 3-Neodymium tris- [ bis- (2-ethylhexyl) phosphate ]

NDV 3-Neodymium Neodecanoate

GdV3 gadolinium versatate

HCF-2, 2,4,4,6, 6-hexachloro-1, 3, 5-triaza-2, 4, 6-triphosphazene;

THF-2, 4, 6-trichloro-2, 4, 6-triphenoxy cyclotriphosphazene;

MPB-maleated polybutadiene

MPI-maleated polyisoprenes

TABLE 2

Formulation of rubber Compounds (ASTM 3189)

Name of raw materials	Parts by weight
		Butadiene rubber	100.0
Carbon Black N330	60.0
		White zinc	3.0
Stearic acid	2.0
		Naphthenic oil	15.0
Gaseous sulfur	1.5
		Sulfenamide T	0.9
In total:	182.40

TABLE 3

Characteristics of the rubber Compound

As can be seen from Table 1, when the aliphatic solvent (A) and the low boiling hydrocarbon C are used ₅ To C ₆ (B) When mixtures of different percentages are taken as solvent, the branching coefficient of the polydienes increases (as evidenced by the low value of the mechanical loss tangent tg δ (1200%), and the viscosity and cold flow of the polymer solution decreases. Compared to the prototype, a significant improvement in polydispersity was noted in all samples obtained according to the proposed invention.

The test results (table 3) of the rubber compositions based on the samples obtained according to the invention illustrate the improvement of the processability of the rubber compositions, expressed by a lower mooney viscosity, improving the interaction of the filler with the polymer matrix, leading to a reduction of the payne effect and an improvement (increase) of the tear resistance.

Claims

1. A process for producing a branched polydiene, the process comprising the steps of:

preparing a catalyst system comprising: (i) a lanthanide compound, (ii) an organoaluminum compound, (iii) a conjugated diene, and (iv) a halogen-containing component;

polymerizing a conjugated diene in a hydrocarbon solvent in the presence of the catalyst system;

introducing a branching agent;

modifying, terminating, degassing, separating and drying the polymer,

characterized in that a branching agent is introduced at a point of conversion of the conjugated diene of at least 96%, said branching agent being selected from the group of chlorine-containing compounds or compounds containing at least two maleic acid segments, wherein the hydrocarbon solvent is a mixture of an aliphatic solvent (A) and a low-boiling hydrocarbon C5 to C6(B) in a weight ratio (A): 50 to 90): 10 to 50).

2. The method according to claim 1, characterized in that the lanthanide compound is selected from the group of neodymium, lanthanum, cerium, praseodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium oxide, holmium, erbium, thulium, ytterbium and lutetium.

3. A method according to claim 2, characterized in that neodymium is used as the lanthanide compound.

4. Method according to claim 1, characterized in that as branching agent, it is selected from the group of chlorinated compounds such as: tin tetrachloride, methyltin trichloride, dimethyltin dichloride, ethyltin trichloride, diethyltin dichloride, n-butyltin trichloride, di-n-butyltin dichloride, phenyltin trichloride, diphenyltin dichloride, silicon tetrachloride, 2,4, 6-trichloro-2, 4, 6-tris (phenoxy) -1,3, 5-triaza-2, 4, 6-triphosphazene, hexachlorocyclotriphosphazene or mixtures thereof.

5. Process according to claim 4, characterized in that the branching agent is chosen from the group of chlorine-containing compounds, preferably from tin tetrachloride, silicon tetrachloride or hexachlorocyclotriphosphazene.

6. A method according to claim 5, characterized in that as chlorine-containing branching agent, tin tetrachloride is most preferred.

7. Process according to claim 1, characterized in that the chlorine-containing branching agent is used in the form of a 1 to 20% by weight solution in an aliphatic solvent.

8. The process according to claim 1, characterized in that the molar ratio of the chlorine-containing branching agent to the lanthanide is from 0.1:1 to 4: 1.

9. Method according to claim 8, characterized in that the preferred molar ratio of the chlorine-containing branching agent to the lanthanide is from 0.2:1 to 3: 1.

10. Process according to claim 9, characterized in that the most preferred molar ratio of the chlorine-containing branching agent to the lanthanide is from 1:1 to 2.5: 1.

11. The process according to claim 1, characterized in that as branching agent comprising at least two maleic acid segments, maleated polydienes, in particular maleated polybutadiene rubber and maleated polyisoprene rubber, are used.

12. The process according to claim 1, characterized in that the molar ratio of the Branching Agent (BA) comprising at least two maleic acid segments to the lanthanide is from 0.1:1 to 5: 1.

13. The process according to claim 12, characterized in that the preferred molar ratio of maleated branching agent to lanthanide is from 0.5:1 to 2: 1.

14. The process according to claim 13, characterized in that the most preferred molar ratio of maleated branching agent to lanthanide is from 0.8:1 to 1: 1.

15. The process according to claim 1, characterized in that the low-boiling hydrocarbon (solvent (B)) is chosen from aliphatic hydrocarbons such as pentane, isopentane, hexane, 2-methylpentane (isohexane), 3-methylpentane, 2-dimethylbutane (neohexane), 2, 3-dimethylbutane, or cycloaliphatic hydrocarbons such as the specific cyclopentanes, methylcyclobutanes, ethylcyclopropanes, used alone or in mixtures with each other.

16. Process according to claim 15, characterized in that as solvent (B) isopentane, cyclopentane, hexane or mixtures thereof are used.

17. Process according to claim 16, characterized in that the solvent (B) is most preferably cyclopentane, hexane or a mixture thereof.

18. Process according to claim 15, characterized in that the proportion of solvent (B) is from 7 to 50% by weight, based on the total weight of the solvent.

19. The process according to claim 18, characterized in that the proportion of solvent (B) in the mixture is preferably from 9 to 20% by weight.

20. The process according to claim 1, characterized in that the proportion of solvent (B) is most preferably from 10 to 15% by weight, based on the total weight of the solvent.

21. The process according to claim 1, characterized in that the aliphatic solvent (A) used for the polymerization is an inert organic solvent selected from: heptane, a hexane-heptane fraction (nefras) of the paraffins of the dearomatized catalytically reformed gasoline having a boiling point temperature limit of 65 ℃ to 75 ℃, and an alicyclic solvent selected from cyclohexane, cycloheptane, or mixtures thereof.

22. Process according to claim 21, characterized in that the solvent (a) is preferably cyclohexane or a mixture of cyclohexane and nefras.

23. The process according to claim 22, characterized in that the solvent (a) is most preferably a mixture of cyclohexane and nefras in a weight ratio of 65:35 to 70:30, respectively.

24. A branched polydiene obtained by the process of any one of claims 1 to 23.

25. A branched polydiene, characterized by a mooney viscosity index after modification of 39 to 52 mooney units, a polydispersity obtained in the range of 2.4 to 2.8, a content of 1.4-cis units of greater than 97 wt.%, a mechanical loss tangent tg δ (1200%) corresponding to the range of 6.41 to 2.87, a plasticity of 0.41 to 0.56, a cold flow of 17.4 to 35.8 mm/hr, and an elastic recovery of 0.99 to 2.17 mm.

26. A rubber composition for tires and rubber products based on the polydiene according to any one of claims 24 to 25.