Process for preparing 1,3-butadiene copolymers

Abstract

The present invention provides a method for preparing copolymers based on at least 1,3-butadiene as monomers and at least one hydrocarbon other than 1,3-butadiene and containing at least one olefinic double bond by solution polymerization utilizing one or more lithium organic compounds as initiators, wherein the polymerization is carried out at a temperature of the reaction mixture between 0°C and 50°C and a pressure of 0.2 to 0.6 MPa, and 55 to 65 wt. % of 1,3-butadiene, based on the total mass of the monomers, is added to the reaction mixture, and the copolymers are prepared by polymerization of at least one hydrocarbon, different from 1,3-butadiene, containing at least one olefinic double bond, as monomers, by solution polymerization utilizing one or more lithium organic compounds as initiators, wherein the polymerization is carried out at a temperature of the reaction mixture between 0°C and 50°C and a pressure of 0.2 to 0.6 MPa, and 55 to 65 wt. % of 1,3-butadiene, based on the total mass of the monomers, is added to the reaction mixture, and the copolymers are prepared by polymerization of at least one hydrocarbon containing at least one olefinic double bond and at least one olefinic double bond, as monomers, by solution polymerization utilizing one or more lithium organic compounds as initiators. and units derived from at least one hydrocarbon other than 1,3-butadiene containing a double bond, the copolymer comprises monomer units derived from 1,3-butadiene of formulas (A), (B), and (C), the proportion of (A) in all monomer units derived from 1,3-butadiene present in the copolymer is at least 80 mol % and the sum of the proportions of (B) and (C) in all monomer units derived from 1,3-butadiene present in the polybutadiene is 20 mol % or less, the number average molecular weight Mn of the copolymer is 2,000 to 5,400 g / mol, and the glass transition temperature T G The temperature is between -15°C and 5°C, and the method relates to the use of the copolymer according to the present invention as a reactive crosslinking agent.

Description

[Technical Field]

[0001] The present invention provides a method for preparing copolymers based on at least 1,3-butadiene as monomers and at least one hydrocarbon that is different from 1,3-butadiene and contains at least one olefinic double bond by solution polymerization utilizing one or more lithium organic compounds as initiators, wherein the polymerization is carried out at a temperature of the reaction mixture between 0°C and 50°C and a pressure of 0.2 to 0.6 MPa, and 55 to 65 wt. % of 1,3-butadiene, based on the total mass of the monomers, is added to the reaction mixture, and the copolymers are prepared by polymerization of at least one hydrocarbon, different from 1,3-butadiene, that contains at least one olefinic double bond, as monomers, by solution polymerization utilizing one or more lithium organic compounds as initiators, wherein the polymerization is carried out at a temperature of the reaction mixture between 0°C and 50°C and a pressure of 0.2 to 0.6 MPa, and 55 to 65 wt. % of 1,3-butadiene, based on the total mass of the monomers, is added to the reaction mixture, and the copolymers are prepared by polymerization of at least one hydrocarbon that is different from 1,3-butadiene and contains at least one olefinic double bond. and units derived from at least one hydrocarbon other than 1,3-butadiene containing a bond, the copolymer comprising monomer units derived from 1,3-butadiene of formulas (A), (B), and (C), wherein the proportion of (A) in all monomer units derived from 1,3-butadiene present in the copolymer is at least 80 mol % and the sum of the proportions of (B) and (C) in all monomer units derived from 1,3-butadiene present in the polybutadiene is 20 mol % or less, the number average molecular weight Mn of the copolymer is 2,000 to 5,400 g / mol, and the glass transition temperature T G The temperature is between -15°C and 5°C, and the method relates to the use of the copolymer according to the present invention as a reactive crosslinking agent. [Background technology]

[0002] Copolymers based on at least 1,3-butadiene and styrene as monomers are well known in the rubber industry. The production of these copolymers (styrene-butadiene rubber) is usually carried out by anionic initiated polymerization.

[0003] US Patent Application Publication No. 2010 / 0206443 describes a method for preparing solution-polymerized styrene butadiene rubber (s-SBR) having a number average molecular weight in the range of about 100,000 to about 475,000 g / mol.

[0004] Chinese Patent No. 100596300C describes a method of anionic initiated polymerization to prepare butadiene-styrene random copolymers that are substantially free of styrene microblocks and have a number average molecular weight Mn of 50,000-600,000 g / mol.

[0005] Chinese Patent No. 109749010A describes random copolymers, their application to tire tread rubber, and their preparation by anionic polymerization. The resulting random copolymers have a number-average molecular weight (Mn) of 70,000 to 220,000 g / mol and a molecular weight distribution index (Mw / Mn) of 1.03 to 1.1, preferably 1.05 to 1.07. The polymerization temperature used is in the range of 50 to 95°C.

[0006] U.S. Patent No. 4,367,325 describes a method for synthesizing high vinyl content (80% or more) rubbers by anionic polymerization. The reaction must be carried out at a low initial temperature of 0°C, followed by a maximum polymerization temperature of 80°C. The document does not disclose the molecular weight of the copolymers produced.

[0007] U.S. Patent No. 4,139,690 describes a method for producing a conjugated diene polymer by polymerizing at least one selected from a group of conjugated diene compounds or copolymerizing a conjugated diene compound with an alkenyl aromatic compound. The polymerization temperature is usually between -80°C and 150°C. This document does not describe the molecular weight of the produced copolymer. The copolymer exhibits a vinyl content of less than 50%. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] US Patent Application Publication No. 2010 / 0206443 [Patent Document 2] Chinese Patent No. 100596300C [Patent Document 3] Chinese Patent No. 109749010A [Patent Document 4] U.S. Patent No. 4,367,325 [Patent Document 5] U.S. Patent No. 4,139,690 Summary of the Invention [Problem to be solved by the invention]

[0009] Against this background, it was an object of the present invention to provide a method for preparing copolymers having a low molecular weight and low dispersity, while at the same time having a high vinyl content.

[0010] Surprisingly, it has been found that these and further objects can be achieved by the subject matter of the present patent application, in particular by the subject matter of the attached independent claims, as well as by the embodiments specified in the dependent claims. [Means for solving the problem]

[0011] Accordingly, the present invention provides a method for preparing copolymers based on at least 1,3-butadiene as monomers and at least one hydrocarbon that, unlike 1,3-butadiene, contains at least one olefinic double bond, by solution polymerization utilizing one or more lithium organic compounds as initiators, the polymerization being carried out at a reaction mixture temperature of 0°C to 50°C and a pressure of 0.2 to 0.6 MPa, and in which 55 to 65 wt. % of 1,3-butadiene, based on the total mass of the monomers, is added to the reaction mixture.

[0012] The present invention further provides a copolymer comprising, as monomers, units derived from 1,3-butadiene and units derived from at least one hydrocarbon other than 1,3-butadiene containing at least one olefinic double bond, the copolymer comprising 1,3-butadiene-derived monomer units of formulae (A), (B), and (C), wherein the proportion of (A) in all the 1,3-butadiene-derived monomer units present in the copolymer is at least 60 mol % and the sum of the proportions of (B) and (C) in all the 1,3-butadiene-derived monomer units present in the polybutadiene is 40 mol % or less, the copolymer has a number average molecular weight Mn of 2,000 to 5,400 g / mol, and a glass transition temperature T G The temperature is between -15℃ and 5℃.

[0013] The present invention also relates to the use of the copolymers according to the invention as reactive crosslinkers.

[0014] The process according to the invention has the advantage that the reaction has a low exothermic reaction potential and can therefore be carried out in a much safer manner.

[0015] The process of the present invention has the additional advantage of being able to prepare copolymers based on at least 1,3-butadiene and at least one hydrocarbon other than 1,3-butadiene that contains at least one olefinic double bond, most preferably styrene, and having lower molecular weights and lower dispersities compared to copolymers known in the art.

[0016] The copolymer according to the present invention has a large number of vinyl groups and therefore has excellent properties when used as a crosslinking agent.

[0017] The copolymers according to the invention can be used as raw materials for addition reactions, making available copolymers with different functionalization. DETAILED DESCRIPTION OF THE INVENTION

[0018] The methods, products, and uses according to the present invention are described below by way of example, without intending that the present invention be limited to these exemplary embodiments. When ranges, general formulas, or classes of compounds are specified below, these are intended to encompass not only the corresponding ranges or groups of compounds explicitly mentioned, but also all subranges and subgroups of compounds that can be obtained by extracting the individual values ​​(ranges) or compounds. When documents are cited in the context of this specification, their contents, with respect to the matters specifically mentioned, fully form part of the disclosure of the present invention. When figures are expressed hereinafter as percentages, they are weight percentages unless otherwise specified. When average values, such as molar mass average values, are specified hereinafter, they are weight averages unless otherwise specified. When material properties, such as viscosity, are mentioned hereinafter, they are material properties at 20°C unless otherwise specified. When chemical (empirical) formulas are used in the present invention, the given indices can be either absolute numbers or average values. In the case of polymeric compounds, the indices preferably represent average values.

[0019] The process according to the invention for preparing copolymers based as monomers on at least 1,3-butadiene and on at least one hydrocarbon which, unlike 1,3-butadiene, contains at least one olefinic double bond, by solution polymerization utilizing one or more lithium organic compounds as initiators, is carried out at a temperature of the reaction mixture between 0°C and 50°C, preferably between 5°C and 45°C.

[0020] The preferred hydrocarbon containing at least one olefinic double bond other than 1,3-butadiene is preferably selected from the group consisting of styrene, divinylbenzene, ethyl-vinylbenzene, diisopropenylbenzene, and isoprene. More preferably, styrene, divinylbenzene, or a mixture thereof is used as the hydrocarbon other than 1,3-butadiene. Most preferably, styrene is used as the hydrocarbon other than 1,3-butadiene.

[0021] Preferably, the starting temperature is in the temperature range of 0 to 20° C. At this starting temperature, preferably at least one of the lithium organic compound and the monomer is added to the reaction mixture, which preferably already contains a solvent.

[0022] In the process according to the present invention, any solvent inert to other compounds present in the reaction mixture can be used as the solvent.Preferred solvents are hydrocarbons, more preferably pentane, isooctane, n-octane, cyclohexane, n-hexane, benzene, toluene, xylene and ethylbenzene, used alone or in mixture.Most preferably, cyclohexane, n-octane or toluene is used as the solvent.Even more preferably, cyclohexane is used as the solvent.

[0023] In the method according to the present invention, any suitable organolithium can be used as an initiator. Typical examples of organolithium initiators useful in the practice of the present invention include alkyllithium, such as ethyllithium, propyllithium, n-butyllithium, sec-butyllithium, or tert-butyllithium; aryllithium, such as phenyllithium or tolyllithium; alkenyllithium, such as vinyllithium or propenyllithium; alkylenedilithium, such as tetramethylenedilithium, pentamethylenedilithium, hexamethylenedilithium, decamethylenedilithium; arylenedilithium, such as 1,3-dilithiobenzene or 1,4-dilithiobenzene; and 1,3,5-tirithiocyclohexane, 1,2,5-trilithionaphthalene, 1,3,5,8-tetralithiodecane, and 1,2,3,5-tetralithio-4-hexylanthracene. Among these initiators, n-butyllithium, sec-butyllithium, tert-butyllithium, and tetramethylenedilithium are preferred, with n-butyllithium being the most preferred initiator.

[0024] The amount of organolithium initiator used depends on the rate of polymerization and the molecular weight of the desired product polymer. Satisfactory results are usually obtained with lithium atoms in the range of 0.2 to 25 grams, preferably 0.5 to 15 grams, per 1000 grams of total monomers used.

[0025] In the process according to the present invention, the polymerization is carried out at a pressure of 0.2 to 0.6 MPa. The pressure can be adjusted using an inert gas. Preferred inert gases used are noble gases, such as helium or argon, or nitrogen. Most preferably, nitrogen is used as the inert gas.

[0026] The process according to the invention can be carried out as a discontinuous (batch) or continuous process. Preferably, the process is carried out as a discontinuous (batch) process.

[0027] In the process according to the present invention, it may be advantageous to first add at least one hydrocarbon different from 1,3-butadiene containing at least one olefinic double bond, preferably styrene, to the reaction mixture, and then add 1,3-butadiene and optional monomers to the reaction mixture after the addition of at least one hydrocarbon different from 1,3-butadiene containing at least one olefinic double bond, preferably styrene. Preferably, styrene is added to the reaction mixture first, and 1,3-butadiene and optional monomers are added to the reaction mixture only after the addition of styrene is complete. When producing a block copolymer, the addition of 1,3-butadiene and optional monomers should begin only after the polymerization of the monomers added first is complete.

[0028] As suggested in U.S. Pat. No. 2,975,160, it may be advantageous to add a Lewis base to the reaction mixture as a randomizing agent. Typical Lewis bases include ethers, tertiary amines, phosphines, and sulfides. Suitable Lewis bases include, for example, diethyl ether, di-n-propyl ether, di-isopropyl ether, di-n-butyl ether, ethyl butyl ether, ethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, tetrahydrofuran, α-methoxytetrahydrofuran, α-methyltetrahydrofuran, dioxane, and 1,2-dimethoxybenzene. Useful tertiary amines include trimethylamine, triethylamine, N,N,N',N'-tetramethylethylenediamine, N-methylmorpholine, N-ethylmorpholine, and N-phenylmorpholine. Suitable sulfide compounds include dialkyl sulfides and diallyl sulfides. Additionally, certain phosphorus compounds, such as hexamethylphosphoric acid triamide, may be used.

[0029] Among the above Lewis bases, diethyl ether, di-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, tetrahydrofuran, dioxane, triethylamine, and N,N,N',N'-tetramethylethylenediamine are preferred. Ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and tetrahydrofuran are more preferred. Tetrahydrofuran is most preferred as the Lewis base.

[0030] According to the present invention, the Lewis base is preferably used in an amount of 0.02 to 100 mol, preferably 0.05 to 30 mol, per mol of lithium atom.

[0031] The process according to the invention can be carried out in any suitable vessel. Preferably, the process is carried out in a stainless steel autoclave as a reactor. The vessel is preferably made of stainless steel. The vessel preferably exhibits a pressure rating of 0.01 to 4.0 MPa.

[0032] The process according to the invention can be used to prepare the copolymers according to the invention.

[0033] The copolymer according to the present invention comprises, as monomers, units derived from 1,3-butadiene and units derived from at least one hydrocarbon other than 1,3-butadiene containing at least one olefinic double bond, and the copolymer contains at least one monomer unit derived from 1,3-butadiene.

[0034] [ka]

[0035] (often referred to in the literature as vinyl units),

[0036] [ka]

[0037] (often called trans units in the literature) and

[0038] [ka]

[0039] (often called cis units in the literature) Including, The proportion of (A) in the total monomer units derived from 1,3-butadiene present in the copolymer is at least 80 mol %, the sum of the proportions of (B) and (C) in the total monomer units derived from 1,3-butadiene present in the polybutadiene is 20 mol % or less, the number average molecular weight Mn of the copolymer is 2,000 to 5,400 g / mol, and the glass transition temperature T G The temperature is -15℃ to 5℃. The ratio of units (A), (B) and (C), T G and a method for determining number average molecular weight is described in the Examples section below.

[0040] The copolymers according to the present invention preferably have a polydispersity, measured as described in the Examples section below, of from 1.0 to 2.6, more preferably from 1.05 to 1.4.

[0041] The copolymers according to the present invention preferably have a glass transition temperature T of between −15° C. and 0° C., measured by the method described in the Examples section below. G It has.

[0042] The copolymers according to the invention are preferably liquid at room temperature (23° C.) Preferably, the copolymers according to the invention have a viscosity of at least 50 Pa*s at 20° C., measured by the method described in the Examples section.

[0043] The copolymer according to the present invention may comprise one or more units derived from styrene, divinylbenzene, ethyl-vinylbenzene, diisopropenylbenzene, and / or isoprene, used as the at least one hydrocarbon different from 1,3-butadiene containing at least one olefinic double bond as a (co)monomer. Preferably, the copolymer comprises one or more units derived from styrene and divinylbenzene as monomers, and more preferably, the copolymer comprises only one or more units derived from styrene as a (co)monomer.

[0044] The copolymer according to the present invention is preferably a random copolymer or a block copolymer, more preferably a random copolymer.

[0045] The copolymers according to the invention can be prepared by any known suitable method. Preferably, the copolymers according to the invention are prepared by the method according to the invention.

[0046] The copolymers according to the invention can be used as reactive crosslinkers, preferably in the preparation of casting compounds.

[0047] The present invention is further illustrated by the following non-limiting examples that illustrate additional features, embodiments, aspects and advantages of the present invention. [Example]

[0048] Raw materials used: Table 1 below provides an overview of the materials used.

[0049] [Table 1]

[0050] Test Method: a) Glass transition temperature T G Decision: Glass transition temperatures were measured by differential scanning calorimetry (DSC). A TA Instruments DSC Q2000 was used for the differential scanning calorimetry. 5-10 mg samples were placed in aluminum pans (Tzero) and heated from -100 to 200 °C at a rate of 10 K / min. Reported values ​​were measured using a TA Universal Analysis from the third heating cycle.

[0051] b) Measurement of molecular weight and dispersity: In the context of the present invention, the number-average and weight-average molecular weights (Mn and Mw, respectively) of polymers are determined by gel permeation chromatography in accordance with DIN 55672-1 using tetrahydrofuran as the eluent and polystyrene as the calibration standard. Measurements were performed in tetrahydrofuran (THF) at a concentration of 5 g / l and a flow rate of 0.3 ml / min at 40°C. Chromatographic separation was achieved using a PSS SDV Micro 5μ / 4.6 x 30 mm precolumn and a PSS SDV Micro linear S 5μ / 4.6 x 300 mm (2x) separation column. Detection was performed using an RI detector. Calibration was performed using polybutadiene standards (PSS-Kit polybutadiene-1,4, Mp 831-106000, product number: PSS-bdfkit, Mn: 1830 / 4330 / 9300 / 18000 / 33500). Dispersion degree D=Mw / Mn.

[0052] c) Viscosity measurement: The viscosity of the copolymers produced was determined in Pa.s in accordance with DIN EN ISO 3219 using a rotational viscometer at the temperature specified in each case.

[0053] d) Determination of the molar ratio of monomer units The molar ratio of the monomer units according to formulas (A), (B), and (C) is determined by IR spectroscopy relative to a polybutadiene standard. For this purpose, the sample (approximately 80-250 mg) is dissolved in 10 ml of carbon disulfide (CS2). If the vinyl content is high, a lower concentration is used, and if the cis content is high, a higher concentration is used. The measurements are carried out in an IR cuvette with a NaCl window and a path length of 0.5 mm. The solvent is subtracted and the spectrum is evaluated in the range 1100-600 cm. -1 For absorbances above 1, repeat the measurement at a lower concentration. Determine the absorbance above baseline for the following signals:

[0054] Trans-1,4-polybutadiene: 968 cm -1 1,2-Polybutadiene: 911 cm -1 cis-1,4-polybutadiene: 730 cm -1 The molar ratio of the monomer components is given by:

[0055] %comp(i)=Ext(i)*100% / (E(i)*c*d*) where: Ext(i) = absorbance above baseline E(i) = extinction coefficient (substance specific, determined by calibration) [E] = L / (g*cm) d = cuvette path length (cm) c = concentration of sample (g / L). [Example 1] 2128 g of dry cyclohexane was first placed in a passivated, pressure-resistant 5 L stainless steel autoclave (Model 4; stainless steel: 1.4571; pressure rating: -0.1 to 4.0 MPa) manufactured by Buchi and cooled to 10 °C. Then, 47.5 g of THF and 2 M n-butyllithium (82.4 ml) were added while maintaining the reaction mixture temperature at 10 °C. 225.4 g of styrene was then added continuously at 0.1 MPa within 15 minutes, ensuring that the reaction mixture temperature did not exceed 15 °C. The pressure in the reactor was then increased to 0.35 MPa using nitrogen, and 351.2 g of 1,3-butadiene was added continuously within 30 minutes while maintaining the temperature at 25 °C. The pressure in the reactor rose to 0.4 MPa. After the addition of 1,3-butadiene was completed, the reaction mixture was stirred at 30 °C for 30 minutes. The reaction mixture was then cooled to 20 °C. 26.4 g of methanol was added at atmospheric pressure and the reaction mixture was stirred for an additional 30 minutes.

[0056] 50 g of TONSIL® filter aid sold by Clariant was then added, and the reaction mixture was then filtered using a Seitz-Pall K800 filter. From the resulting filtrate, one or more solvents were removed using a rotary evaporator, reducing the atmospheric pressure to 10 mbar. 550 g of a clear, viscous liquid was obtained, corresponding to a yield of approximately 95%. The product was analyzed, and the results are shown in Table 2 below. [Example 2] 715 g of dry cyclohexane was first placed in a passivated, pressure-resistant 5 L stainless steel autoclave (Model 4; stainless steel: 1.4571; pressure rating: -0.1 to 4.0 MPa) manufactured by Buchi and cooled to 7 °C. Then, 358 g of THF and 2 M n-butyllithium (229.8 ml) were added while maintaining the reaction mixture temperature at 10 °C. Then, 338.9 g of styrene was added continuously at 0.1 MPa pressure within 25 minutes, ensuring that the reaction mixture temperature did not exceed 15 °C. The pressure in the reactor was then increased to 0.35 MPa using nitrogen, and 920.1 g of 1,3-butadiene was added continuously within 65 minutes while maintaining the temperature at 25 °C. The pressure in the reactor rose to 0.4 MPa. After the addition of 1,3-butadiene was completed, the reaction mixture was stirred at 40 °C for 30 minutes. The reaction mixture was then cooled to 20 °C. At atmospheric pressure, 51.3 g of methanol was added and the reaction mixture was stirred for an additional 30 minutes.

[0057] 30 g of TONSIL® filter aid sold by Clariant was then added, and the reaction mixture was then filtered using a Seitz-Pall K800 filter. The filtrate was then removed from the resulting stock solution using a rotary evaporator, reducing the atmospheric pressure to 10 mbar to remove one or more solvents. 1230 g of a clear, viscous liquid was obtained, corresponding to a yield of approximately 94%. The product was analyzed, and the results are shown in Table 2 below. [Example 3] 2180 g of dry cyclohexane was first placed in a passivated, pressure-resistant 5 L stainless steel autoclave (Model 4; stainless steel: 1.4571; pressure rating: -0.1 to 4.0 MPa) manufactured by Buchi and cooled to 10 °C. Then, 41.8 g of THF and 2 M n-butyllithium (119 ml) were added while maintaining the reaction mixture temperature at 10 °C. 296.7 g of styrene was then added continuously at 0.1 MPa within 30 min, ensuring that the reaction mixture temperature did not exceed 15 °C. The pressure in the reactor was then increased to 0.35 MPa using nitrogen, and 290 g of 1,3-butadiene was added continuously within 45 min while maintaining the temperature at 20 °C. The pressure in the reactor rose to 0.4 MPa. After the addition of 1,3-butadiene was completed, the reaction mixture was stirred at 40 °C for 60 min. The reaction mixture was then cooled to 20 °C. 38.2 g of methanol was added at atmospheric pressure and the reaction mixture was stirred for an additional 30 minutes at a temperature of 23°C.

[0058] 80 g of TONSIL® filter aid sold by Clariant was then added, and the reaction mixture was then filtered using a Seitz-Pall K800 filter. The filtrate was obtained as a stock solution, and one or more solvents were removed from the stock solution using a rotary evaporator, reducing the atmospheric pressure to 10 mbar. 580 g of a clear, viscous liquid was obtained, corresponding to a yield of approximately 99%. The product was analyzed, and the results are shown in Table 2 below. [Example 4] 2170 g of dry cyclohexane was first placed in a passivated, pressure-resistant 5 L stainless steel autoclave (Model 4; stainless steel: 1.4571; pressure rating: -0.1 to 4.0 MPa) manufactured by Buchi and cooled to 10 °C. Then, 25.1 g of THF and 2 M n-butyllithium (62 ml) were added while maintaining the reaction mixture temperature at 10 °C. 225.9 g of styrene was then added continuously at 0.1 MPa within 30 min, ensuring that the reaction mixture temperature did not exceed 15 °C. The pressure in the reactor was then increased to 0.35 MPa using nitrogen, and 353 g of 1,3-butadiene was added continuously within 45 min while maintaining the temperature at 20 °C. The pressure in the reactor rose to 0.4 MPa. After the addition of 1,3-butadiene was completed, the reaction mixture was stirred at 30 °C for 20 min. The reaction mixture was then cooled to 20 °C. 20 g of methanol was added at atmospheric pressure and the reaction mixture was stirred for a further 30 minutes at a temperature of 23°C.

[0059] 20 g of TONSIL® filter aid sold by Clariant was then added, and the reaction mixture was then filtered using a Seitz-Pall K800 filter. From the resulting filtrate, one or more solvents were removed using a rotary evaporator, reducing the atmospheric pressure to 10 mbar. 551 g of a clear, viscous liquid was obtained, corresponding to a yield of approximately 95%. The product was analyzed, and the results are shown in Table 2 below. [Example 5] 1378 g of dry n-octane was first placed in a passivated, pressure-resistant 5 L stainless steel autoclave (Model 4; stainless steel: 1.4571; pressure rating: -0.1 to 4.0 MPa) manufactured by Buchi and cooled to 10 °C. Subsequently, 84.8 g of THF and 2 M n-butyllithium (147 ml) were added while maintaining the reaction mixture temperature at 10 °C. 400.6 g of styrene was then added continuously at 0.1 MPa within 60 minutes, ensuring that the reaction mixture temperature did not exceed 18 °C. The pressure in the reactor was then increased to 0.35 MPa using nitrogen, and 623 g of 1,3-butadiene was added continuously within 65 minutes while maintaining the temperature at 28 °C. The pressure in the reactor rose to 0.4 MPa. After the addition of 1,3-butadiene was completed, the reaction mixture was stirred at 35 °C for 20 minutes. The reaction mixture was then cooled to 20 °C. 47 g of methanol was added at atmospheric pressure and the reaction mixture was stirred for a further 30 minutes at a temperature of 23°C.

[0060] 80 g of TONSIL® filter aid sold by Clariant was then added, and the reaction mixture was then filtered using a Seitz-Pall K800 filter. The filtrate was obtained as a stock solution, and one or more solvents were removed from the stock solution using a rotary evaporator, reducing the atmospheric pressure to 10 mbar. 998 g of a clear, viscous liquid was obtained, corresponding to a yield of approximately 97%. The product was analyzed, and the results are shown in Table 2 below. Example 6: Block copolymer 1255 g of dry cyclohexane was first placed in a passivated, pressure-resistant 5 L stainless steel autoclave (Model 4; stainless steel: 1.4571; pressure rating: -0.1 to 4.0 MPa) manufactured by Buchi and cooled to 10 °C. Subsequently, 55 g of THF and 2 M n-butyllithium (190 ml) were added while maintaining the reaction mixture temperature at 10 °C. 260 g of styrene was then added continuously at 0.1 MPa within 30 min, ensuring that the reaction mixture temperature did not exceed 15 °C. The pressure in the reactor was then increased to 0.35 MPa using nitrogen, and 811 g of 1,3-butadiene was added continuously within 45 min while maintaining the temperature at 20 °C. The pressure in the reactor rose to 0.4 MPa. After the addition of 1,3-butadiene was completed, the reaction mixture was stirred at 30 °C for 30 min. Subsequently, a second portion of 260 g of styrene was added continuously within 20 minutes at 30° C. The pressure was released to atmospheric pressure, 61 g of methanol was added and the reaction mixture was stirred for a further 30 minutes at a temperature of 23° C.

[0061] 30 g of TONSIL® filter aid sold by Clariant was then added, and the reaction mixture was then filtered using a Seitz-Pall K800 filter. The filtrate was then evaporated using a rotary evaporator at atmospheric pressure of 10 mbar to remove one or more solvents. 1224 g of a clear, viscous liquid was obtained, corresponding to a yield of approximately 92%. The product was analyzed, and the results are shown in Table 2 below. Example 7: Terpolymer 1403 g of dry toluene was first placed in a passivated, pressure-resistant 5 L stainless steel autoclave (Model 4; stainless steel: 1.4571; pressure rating: -0.1 to 4.0 MPa) manufactured by Buchi and cooled to 9 °C. Then, 55 g of THF and 2 M n-butyllithium (185 ml) were added while maintaining the reaction mixture temperature at 10 °C. 459 g of styrene was then added continuously at 0.1 MPa pressure within 30 min, ensuring that the reaction mixture temperature did not exceed 15 °C. The pressure in the reactor was then increased to 0.35 MPa using nitrogen, and 811 g of 1,3-butadiene was added continuously within 45 min while maintaining the temperature at 20 °C. The pressure in the reactor rose to 0.4 MPa. Next, 127 g of divinylbenzene was added at 20 °C, and the mixture was stirred for an additional 20 min at 0.4 MPa pressure and 20 °C. 61 g of methanol was added at atmospheric pressure and the reaction mixture was stirred for a further 30 minutes at a temperature of 23°C.

[0062] 30 g of TONSIL® filter aid sold by Clariant was then added, and the reaction mixture was then filtered using a Seitz-Pall K800 filter. From the resulting filtrate, one or more solvents were removed using a rotary evaporator, reducing the atmospheric pressure to 10 mbar. 1270 g of a clear, viscous liquid was obtained, corresponding to a yield of approximately 91%. The product was analyzed, and the results are shown in Table 2 below. [Example 8] 695 g of dry cyclohexane was first placed in a passivated, pressure-resistant 5 L stainless steel autoclave (Model 4; stainless steel: 1.4571; pressure rating: -0.1 to 4.0 MPa) manufactured by Buchi and cooled to 10 °C. Subsequently, 885 g of THF and 2 M n-butyllithium (260 ml) were added while maintaining the reaction mixture temperature at 15 °C. 424 g of styrene was then added continuously at 0.1 MPa within 30 minutes, ensuring that the reaction mixture temperature did not exceed 15 °C. The pressure in the reactor was then increased to 0.35 MPa using nitrogen, and 293 g of 1,3-butadiene was added continuously within 30 minutes while maintaining the temperature at 20 °C. The pressure in the reactor rose to 0.4 MPa. After the addition of 1,3-butadiene was completed, the reaction mixture was stirred at 30 °C for 20 minutes. The reaction mixture was then cooled to 20 °C. 85 g of methanol was added at atmospheric pressure and the reaction mixture was stirred for a further 30 minutes at a temperature of 23°C.

[0063] 30 g of TONSIL® filter aid sold by Clariant was then added, and the reaction mixture was then filtered using a Seitz-Pall K800 filter. From the resulting filtrate, one or more solvents were removed using a rotary evaporator, reducing the atmospheric pressure to 10 mbar. 667 g of a clear, viscous liquid was obtained, corresponding to a yield of approximately 93%. The product was analyzed, and the results are shown in Table 2 below.

[0064] [Table 2]

[0065] Vinyl content (%) = Proportion (mol%) of (A) in all 1,3-butadiene-derived monomer units present in the copolymer From Table 2 it can be seen that the process according to the invention makes it possible to obtain copolymers and terpolymers based on at least 1,3-butadiene and styrene as monomers, having relatively low number-average molecular weights Mn of 1,350 to 5,400 g / mol and dispersities D of 1.0 to 1.25.

Claims

1. 1. A process for preparing copolymers based on at least 1,3-butadiene and at least one hydrocarbon, different from 1,3-butadiene, as monomers, which contain at least one olefinic double bond, by solution polymerization utilizing one or more lithium organic compounds as initiators, characterized in that the polymerization is carried out at a temperature of the reaction mixture between 0°C and 50°C, preferably between 5°C and 45°C, and at a pressure of 0.2 to 0.6 MPa, and in that 55 to 65% by weight of 1,3-butadiene, based on the total mass of the monomers, is added to the reaction mixture.

2. 2. The process according to claim 1, characterized in that pentane, isooctane, n-octane, cyclohexane, n-hexane, benzene, toluene, xylene and ethylbenzene are used alone or in admixture as solvents.

3. 3. The process according to claim 1, wherein n-butyllithium is used as the initiator.

4. 4. The method according to claim 1, wherein the method is carried out as a discontinuous method.

5. 5. The method according to claim 1, wherein first at least one hydrocarbon different from 1,3-butadiene which contains at least one olefinic double bond is added to the reaction mixture, and after the addition of the at least one hydrocarbon different from 1,3-butadiene which contains at least one olefinic double bond, the 1,3-butadiene and optional monomers are added to the reaction mixture.

6. A copolymer comprising units derived from 1,3-butadiene as monomers and units derived from at least one hydrocarbon other than 1,3-butadiene containing at least one olefinic double bond, wherein the copolymer comprises the monomer units (A), (B), and (C) derived from 1,3-butadiene. 【Chemistry 1】 【Chemistry 2】 and 【Transformation 3】 Including, the proportion of (A) in the total monomer units derived from 1,3-butadiene present in the copolymer is at least 80 mol %, the sum of the proportions of (B) and (C) in the total monomer units derived from 1,3-butadiene present in the polybutadiene is 20 mol % or less, the copolymer has a number average molecular weight Mn of 2,000 to 5,400 g / mol, and a glass transition temperature T measured by the method described herein Ｇ is -15°C to 5°C, Copolymer.

7. 7. The copolymer of claim 6, having a polydispersity, measured as described herein, of from 1.0 to 2.6, more preferably from 1.05 to 1.

4.

8. The glass transition temperature T measured by the method described herein Ｇ 8. The copolymer according to claim 6, wherein the temperature is between -15°C and 0°C.

9. Copolymer according to any one of claims 6 to 8, characterized in that it comprises, as monomers, one or more units derived from styrene, divinylbenzene, ethyl-vinylbenzene, diisopropenylbenzene or isoprene.

10. 10. Copolymer according to claim 9, characterized in that it comprises one or more units derived from styrene and divinylbenzene as monomers, more preferably one or more units derived exclusively from styrene as monomer.

11. Copolymer according to any one of claims 6 to 10, characterized in that the copolymer is a random or block copolymer, more preferably a random copolymer.

12. A copolymer according to any one of claims 6 to 11, obtainable by the process according to any one of claims 1 to 5.

13. Use of a copolymer according to any one of claims 6 to 12 as a reactive crosslinking agent, preferably for the preparation of a casting compound.

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