Polar additive for the synthesis of copolymers of vinyl aromatic monomers and conjugated diene monomers with high vinyl aromaticity and low vinyl content

Abstract

To provide a copolymer of a vinyl aromatic monomer and a conjugated diene monomer, the copolymer having a high vinyl aromatic content, a low vinyl content, and a low blockiness. The present invention relates to the use of N,N',N''-substituted hexahydro-1,3,5-triazines in the anionic polymerization of conjugated diene monomers and vinyl aromatic monomers. The use of these polar additives allows for the production of copolymers with both high vinyl aromaticity and low vinyl content, while allowing for tunable blockiness of the vinyl aromatic units.

Description

[Technical field]

[0001] The present invention relates to the use of certain polar additives for the preparation of copolymers of vinyl aromatic monomers and conjugated diene monomers with high vinyl aromaticity and low vinyl content by anionic polymerization. The polar additives result in copolymers with particularly high vinyl aromatic content and distinct blockiness of the vinyl aromatics in the copolymer. The copolymers of the present invention have the following characteristics: (a) a vinyl aromatic content of about 30 to about 80 weight percent, based on the total weight of the polymer; (b) a content of vinyl aromatic blocks with more than 4 repeat units of about 0.01 to about 32 weight percent, based on the total vinyl aromatic content; and (c) a vinyl content of more than 8 to about 45 weight percent, based on the total conjugated diene polymerization fraction. [Background technology]

[0002] The preparation of copolymers of conjugated diene monomers (e.g., 1,3-butadiene) with randomized high vinyl aromatic content (e.g., 30-50 weight percent styrene based on the total weight of the polymer) or partially blocked ultra-high styrene content (55-78 weight percent styrene based on the total weight of the polymer) is not possible with standard randomizing agents such as N,N,N',N'-tetramethylethylenediamine (TMEDA) if one wishes to obtain copolymers with low vinyl content (45% or less). This is because these types of agents strongly promote the 1,2-addition of diene monomers, i.e., it results in copolymers with high vinyl content. Moreover, the content of vinyl aromatic monomers and the block length of vinyl aromatic repeat units tend to decrease with increasing amounts of polar additives.

[0003] Patent Document 1 describes a block styrene content of greater than 4 consecutive units of about 40 to about 70 weight percent based on the total styrene content in the polymer, b) a vinyl content of about 25 to about 80 weight percent based on the total amount of polymerized 1,3-butadiene, c) a styrene content of about 20 to about 75 weight percent based on the total weight of the polymer, and d) a molecular weight distribution (M) of 1.5 or less. w / M n ) teaches the preparation of a polymer having a styrene content of about 40 to about 70 weight percent, and a vinyl content of about 30 to about 80 weight percent, based on the polymerized 1,3-butadiene. The process involves polymerization in the presence of i) an initiator, ii) a potassium alcoholate, and iii) a polar agent which is ditetrahydrofurylpropane (more specifically, 2,2-di(2-oxolanyl)propane). Similarly, US Pat. No. 5,399,633 teaches a polymerization process which requires two polar agents. The first polar agent is a bis-amino alkylene such as tetramethylethylenediamine. The second polar agent is ditetrahydrofurylpropane (more specifically, 2,2-di(2-oxolanyl)propane). The resulting polymer has a styrene content of about 40 to about 70 weight percent, and b) a vinyl content of about 30 to about 80 weight percent, based on the polymerized 1,3-butadiene. The content of block styrene consisting of more than 6 consecutive styrene units shown in the examples is 6 to 17%.

[0004] Patent document 3 teaches block copolymers comprising at least two hard blocks S1 and S2 made from vinyl aromatic monomers and, between them, at least one random soft block B / S made from vinyl aromatic monomers and diene monomers, where the proportion of hard blocks is greater than 40% by weight, based on the total block copolymer. Patent document 4 teaches, for example, the preparation of styrene-butadiene copolymers with a content of styrene sequences with 4 to 20 styrene units of 40 to 65% by weight of the total styrene content.

[0005] Patent Document 5 describes a block styrene content of greater than 6 consecutive units of about 15 to about 35 weight percent based on the total styrene content in the polymer, b) a vinyl content of about 25 to about 80 weight percent based on the total amount of 1,3-butadiene polymerized, c) a styrene content of about 35 to about 75 weight percent based on the total weight of the polymer, and d) a molecular weight distribution (M) of 1.5 or less. w / M n ), which teaches the preparation of a polymer having the following structure: The process involves polymerization in the presence of an initiator, a potassium alcoholate, and a polar agent which is a dialkyl ether. The block styrene content of more than four consecutive units may be 60 to 80 weight percent based on the total styrene content.

[0006] Non-Patent Document 1 teaches that the application of polar additives (modifiers) promotes the randomization of styrene in styrene-butadiene copolymers and increases the content of vinyl groups. The homopolymerization rate constant of styrene is higher than that of 1,3-butadiene. However, when styrene and butadiene are mixed, the reactivity is reversed and 1,3-butadiene tends to polymerize faster than styrene. This phenomenon is observed because, compared to styrene, 1,3-butadiene tends to form more stable π bonds with living centers, and therefore 1,3-butadiene polymerization is favored. When the concentration of butadiene in a styrene / butadiene mixture is very low, styrene begins to polymerize and a tapered or block copolymer is obtained (Patent Document 6). This document also teaches that copolymers of styrene and butadiene with very low blockiness can be obtained by carrying out the reaction at high temperatures. The copolymers have a low styrene content, typically 25% or less. Furthermore, the addition of a Lewis base, a Lewis acid (Patent Document 7), a mixture of a Lewis base and an acid, or a π-donor group to the polymerization system makes the reactivities of styrene and butadiene equal, which makes it possible to obtain random styrene-butadiene copolymers.

[0007] US Pat. No. 5,399,633 discloses, for example, that metal salts of cyclic alcohols (such as sodium dodecylbenzenesulfonate, SDBS) can be used in the lithium-initiated solution polymerization of diene monomers (styrene, isoprene) in the absence of polar additives such as Lewis acids, thus obtaining rubbers with low vinyl content.

[0008] US Patent No. 5,399,663 discloses that a polar additive system consisting of two Lewis bases, ditetrahydrofurylpropane (DOP) and tetramethylethylenediamine (TMEDA), results in high styrene, high vinyl SBR with narrow molecular weight distribution, high monomer conversion, short reaction times and improved polymer chain life compared to the use of TMEDA alone. Furthermore, US Patent No. 5,399,663 and US Patent No. 5,399,663 teach that the use of ditetrahydrofurylpropane in a batch, semi-batch or continuous process can give low or high vinyl styrene-butadiene polymers (depending on the reaction conditions and the concentration of the polar additive applied) that vary widely, where the styrene content can vary from 10 to 70 weight percent, based on the weight of the polymer, the block styrene can be less than 8 weight percent or between 27 to 50 weight percent, and the vinyl content can be 12 to 40 or 30 to 80 weight percent (per butadiene fraction).

[0009] It is also possible to randomize styrene along the polymer chain by copolymerizing styrene and butadiene with different monomer (styrene, butadiene) charge ratios and running the process under styrene-rich conditions (US Pat. No. 5,399,433). The polymerization is carried out in two polymerization zones, resulting in a living styrene-butadiene rubber cement with a vinyl content of less than 10%, where less than 5% of the total amount of repeat units derived from styrene in the polymer chain are in blocks containing 5 or more styrene repeat units. However, to obtain a low vinyl polymer with low blockiness, the conversion in the second reactor must be kept below 95%, preferably below 93%, resulting in a product from which a significant amount of residual monomer must be removed. The polymers usually have a low styrene content of 10 to 30 weight percent.

[0010] US Patent No. 5,399,633 teaches that triazines can be used as randomizers in the copolymerization of butadiene and styrene in the presence of n-butyllithium as a catalyst. The triazine randomizers provide vinyl contents ranging from 13.5 to 33.2 weight percent based on the diene polymerized fraction in a low styrene copolymer (i.e., 25 weight percent styrene, 75 weight percent 1,3-butadiene).

[0011] Thus, there is a need in the art for a process that provides copolymers of vinyl aromatic monomers and conjugated diene monomers, where the copolymers have 1) high vinyl aromatic content, 2) low vinyl content, and 3) low blockiness. This should be a simple and effective process, i.e., it should not necessarily require that the polymerization be carried out in two stages or at low conversion.

[0012] As described in US Pat. No. 5,999,136, the use of randomizers can result in high vinyl SSBRs with low block styrene content (greater than 6 consecutive units of styrene) of less than 10%. Long block styrenes can worsen hysteresis, as reported, for example, by S. Futamura and G. Day, who observed an approximately 18% deterioration in tan delta at 60°C when increasing the block styrene content from 2 to about 7% in a carbon black-filled compound (Non-Patent Document 2). In contrast, the incorporation of small styrene blocks can improve wear and tensile strength, especially in silica compounds, as reported by Non-Patent Document 3. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] U.S. Patent No. 8927644B2 [Patent Document 2] US Patent Application Publication No. 2013 / 0345379A1 [Patent Document 3] U.S. Patent No. 6,521,712 B1 [Patent Document 4] European Patent Application Publication No. 0798339A2 [Patent Document 5] U.S. Patent No. 8927645B2 [Patent Document 6] U.S. Pat. No. 3,558,575 [Patent Document 7] U.S. Pat. No. 3,787,377 [Patent Document 8] U.S. Patent No. 6,583,244 B1 [Patent Document 9] U.S. Patent No. 9000109B2 [Patent Document 10] International Publication No. WO2011 / 157742A1 [Patent Document 11] U.S. Patent No. 8981000B2 [Patent Document 12] U.S. Patent No. 6,372,863 [Patent Document 13] U.S. Patent No. 3,498,960B [Non-patent literature]

[0014] [Non-Patent Document 1] Antkowiak et al., J. Polym. Sci., Part A-1, 1972, 10, 1319 [Non-Patent Document 2] S. Futamura and G. Day, Kautschuk Gummi Kunststoffe, 1987, 40, No. 1, 39-43 [Non-Patent Document 3] I. Hattori et al., 143rd Meeting of the Rubber Division of the ACS, Spring 1993, Paper 22 Summary of the Invention [Problem to be solved by the invention]

[0015] It is an object of the present invention to provide copolymers of vinyl aromatic monomers and conjugated diene monomers which have high vinyl aromatic content, low vinyl content and low blockiness. [Means for solving the problem]

[0016] Surprisingly, it has been discovered that high styrene, low vinyl vinyl aromatic (e.g., styrene)-conjugated diene (e.g., butadiene) rubbers can be obtained by anionic polymerization of vinyl aromatic and conjugated diene monomers in the presence of an organometallic initiator and a specific polar modifier. The polar modifier (additive) has the following formula (I):

[0017] [ka]

[0018] [In the formula, R 1 , R 3 , and R 5 each is independently an alkyl, alkenyl, cycloalkyl, cycloalkenyl, or aryl group, or a combination thereof; R 1 , R 3 , and R 5 each having 1 to 20 carbon atoms; And R 2 , R 4 , and R 6 is independently H, an alkyl, alkenyl, cycloalkyl, cycloalkenyl, or aryl group, or a combination thereof; 2 , R 4 , and R 6 may each have up to 20 carbon atoms. and N,N',N''-substituted hexahydro-1,3,5-triazine having the formula:

[0019] Hexahydro-1,3,5-triazines according to formula (I) act as polar modifiers, despite being Lewis bases, and do not strongly affect the vinyl content while providing excellent randomization. Depending on the total styrene content, the desired block styrene content, the desired vinyl content and the polymerization temperature, the hexahydro-1,3,5-triazines according to the invention are typically used in an amount such that the molar ratio of polar modifier to initiator is in the range of 0.01 to 50:1.

[0020] The copolymers of the present invention produced by anionic polymerization with hexahydro-1,3,5-triazines according to formula (I) are rubbery copolymers of vinyl aromatic monomers and conjugated diene monomers and are characterized by a vinyl aromatic monomer content of from about 30 to about 80 weight percent.

[0021] According to a first aspect, the present invention relates to the use of a hexahydro-1,3,5-triazine according to formula (I) as defined above, in the preparation of an elastomeric copolymer. According to a second aspect, the present invention relates to a method for producing an elastomeric copolymer.

[0022] According to a third aspect, the present invention relates to an elastomeric copolymer having: a) a vinyl aromatic monomer content of from about 30 to about 80 weight percent, based on the total weight of the polymer; b) a vinyl aromatic monomer block content having more than 4 repeat units of from about 0.01 to about 32 weight percent, based on the total vinyl aromatic monomer content; and c) a vinyl content of from greater than 8 to about 45 weight percent, based on the total conjugated diene polymerized fraction.

[0023] According to a fourth aspect, the present invention relates to a process for preparing a rubber comprising vulcanizing an elastomeric copolymer according to the third aspect in the presence of one or more vulcanizing agents. According to a fifth aspect, the present invention relates to a rubber obtainable according to the process of the fourth aspect.

[0024] According to a sixth aspect, the present invention relates to a rubber composition comprising a rubber component comprising a rubber according to the fifth aspect. According to a seventh aspect, the present invention relates to a tire component comprising a rubber composition according to the sixth aspect.

[0025] Finally, according to an eighth aspect, the present invention relates to a tyre comprising a tyre component according to the seventh aspect. The present invention is based on the surprising discovery that the use of the hexahydro-1,3,5-triazine additive of formula (I) makes it possible to easily prepare copolymers having a vinyl aromatic monomer content of about 30 to about 80% by weight without the need for a complex two-stage process (compared to US Pat. No. 5,399,323) or the need to carry out the polymerization at low conversion.

[0026] The copolymers of vinyl aromatic monomers (especially styrene) and conjugated diene monomers (especially 1,3-butadiene) can be classified as high styrene, low vinyl styrene butadiene rubbers (HS-LV-SBR, total styrene content in the range of 30-50 wt%) and ultra-high styrene, low vinyl styrene butadiene rubbers (UHS-LV-SBR, total styrene content in the range of 50-80 wt%). For both HS-LV-SBR and UHS-LV-SBR obtained according to the present invention, the total vinyl content is greater than 8 weight percent and ranges up to about 45 weight percent, based on the total conjugated diene polymerization fraction. Thus, under the following typical polymerization conditions, i.e., weight percent content of styrene of 30-80%, hexahydro-1,3,5-triazine / initiator molar ratio in the range of 0.01-50:1, and polymerization temperature below 100°C, HS-LV-SBR and UHS-LV-SBR with controllable styrene block content can be easily obtained. Effect of the Invention

[0027] According to the present invention, it has been possible to provide copolymers of vinyl aromatic monomers and conjugated diene monomers, the copolymers having high vinyl aromatic content, low vinyl content and low blockiness. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hexahydro-1,3,5-triazine of formula (I) According to a first aspect, the present invention provides a compound of formula (I):

[0029] [ka]

[0030] [In the formula, R 1 , R 3 , and R 5 each is independently an alkyl, alkenyl, cycloalkyl, cycloalkenyl, or aryl group, or a combination thereof; R 1 , R3 , and R 5 each having 1 to 20 carbon atoms; And R 2 , R 4 , and R 6 is independently H, an alkyl, alkenyl, cycloalkyl, cycloalkenyl, or aryl group, or a combination thereof; 2 , R 4 , and R 6 may each have up to 20 carbon atoms. in the preparation of copolymers of one or more conjugated diene monomers and one or more vinyl aromatic monomers, said preparation being by anionic polymerization in the presence of one or more anionic initiators, and said copolymers having a vinyl aromatic monomer content of about 30 to about 80 weight percent, based on the total weight of the copolymer.

[0031] Preferably, R 1 , R 3 , and R 5 are the same and are selected from alkyl, alkenyl, cycloalkyl, cycloalkenyl and aryl groups. More preferably, R 1 , R 3 , and R 5 are the same and are alkyl groups having 1 to 20 carbon atoms, more preferably 1 to 6 carbon atoms. Most preferably, R 1 , R 3 , and R 5 are each methyl.

[0032] Also, R 2 , R 4 , and R 6 are preferably the same and are selected from H, alkyl, alkenyl, cycloalkyl, cycloalkenyl and aryl groups. Most preferably, R 2 , R 4 , and R 6 are H, respectively.

[0033] Thus, for compounds of formula (I), R 1 , R 3 , and R 5 are each methyl, and R 2 , R 4 , and R 6 Most preferably, each is H (hexahydro-N,N',N''-trimethyltriazine).

[0034] Preferably, the molar ratio of hexahydro-1,3,5-triazine of formula (I) to anionic initiator is in the range of from 0.01 to 50, more preferably in the range of from 0.1 to 30 (if more than one hexahydro-1,3,5-triazine of formula (I) is used, the amount of hexahydro-1,3,5-triazine for calculating this ratio is the total amount of hexahydro-1,3,5-triazine of formula (I) as presented).

[0035] Preferred anionic initiators are organolithium compounds. Organolithium Compounds As the organolithium compound, those having a hydrocarbon group having 1 to 20 carbon atoms are preferred. Examples are methyllithium, ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert-octyllithium, n-decyllithium, phenyllithium, 2-naphthyllithium, 2-butylphenyllithium, 4-phenylbutyllithium, cyclohexyllithium, cyclopentyllithium, and the reaction product of diisopropenylbenzene and butyllithium. Of these compounds, n-butyllithium and sec-butyllithium are preferred.

[0036] Lithium Amide Examples of the lithium amide compound are lithium hexamethyleneimide, lithium pyrrolidide, lithium piperidide, lithium heptamethyleneimide, lithium dodecamethyleneimide, lithium dimethylamide, lithium diethylamide, lithium dibutylamide, lithium dipropylamide, lithium diheptylamide, lithium dihexylamide, lithium dioctylamide, lithium di-2-ethylhexylamide, lithium didecylamide, lithium N-methyl-piperazide, lithium ethylpropylamide, lithium ethylbutylamide, lithium ethylbenzylamide and lithium methylphenethylamide. Among these compounds, from the viewpoint of polymerization initiation ability, cyclic lithium amides such as lithium hexamethyleneimide, lithium pyrrolidide, lithium piperidide, lithium heptamethyleneimide and lithium dodecamethyleneimide are preferred, and lithium hexamethyleneimide, lithium pyrrolidide and lithium piperidide are particularly preferred.

[0037] Also, when two or more anionic initiators are used, the total molar amounts are used in calculating the molar ratios referred to herein. The preparation of the copolymer of the present invention is possible by using the hexahydro-1,3,5-triazine of formula (I) as the sole polar modifier or by applying the combination of the hexahydro-1,3,5-triazine of formula (I) with an additional polar modifier (such as Lewis base and / or Lewis acid) that also promotes the formation of vinyl groups. It is preferred that one or more additional polar modifiers are used in anionic polymerization together with the hexahydro-1,3,5-triazine of formula (I). Preferably, the additional polar modifier is selected from one or more of Lewis bases and Lewis acids. More preferably, the additional polar modifier is selected from ditetrahydrofurylpropane, tetramethylethylenediamine, sodium mentholate, and tetrahydrofuran.

[0038] Thus, the polymerization process of the present invention is typically carried out in the presence of a polar modifier such as a tertiary amine, an alcoholate or an alkyl tetrahydrofurfuryl ether. Some representative examples of specific polar modifiers that can be used include methyl tetrahydrofurfuryl ether, ethyl tetrahydrofurfuryl ether, propyl tetrahydrofurfuryl ether, butyl tetrahydrofurfuryl ether, hexyl tetrahydrofurfuryl ether, octyl tetrahydrofurfuryl ether, dodecyl tetrahydrofurfuryl ether, diethyl ether, di-n-propyl ether, diisopropyl ether, di-n-butyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, trimethylamine, triethylamine, N,N,N',N'-tetramethylethylenediamine, N-methylmorpholine, N-ethylmorpholine, and N-phenylmorpholine.

[0039] The potassium or sodium compound may be added together with the polymerization initiator when it is intended to increase the reactivity of the polymerization initiator, when it is intended to randomly arrange the aromatic vinyl compound in the resulting polymer, or when it is intended to enable the aromatic vinyl compound to be contained as a single chain in the resulting polymer. As the potassium or sodium added together with the polymerization initiator, for example, the following can be used: alkoxides and phenoxides represented by isopropoxide, tert-butoxide, tert-amyl oxide, n-heptoxide, benzyl oxide, and phenoxide; potassium or sodium salts of organic sulfonic acids such as dodecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, hexadecylbenzenesulfonic acid, and octadecylbenzenesulfonic acid.

[0040] Preferably, the molar ratio of the additional polar modifier to the anionic initiator is in the range of about 0.01 to about 50, more preferably in the range of about 0.1 to about 10. When two or more additional polar modifiers are used, the total molar amount of the additional polar modifiers is used to calculate the molar ratios referred to herein.

[0041] The conjugated diene monomer used according to the present invention is preferably selected from 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 2,3-dimethyl-1,3-pentadiene, 2-phenyl-1,3-butadiene and 4,5-diethyl-1,3-octadiene. More preferably, the conjugated diene monomer is selected from 1,3-butadiene and isoprene. In particular, the conjugated diene monomer used according to the present invention is 1,3-butadiene.

[0042] Also, the vinyl aromatic monomer used according to the present invention is preferably selected from styrene, 1-vinylnaphthalene, 3-methylstyrene, 3,5-diethylstyrene, 4-propylstyrene, 2,4,6-trimethylstyrene, 4-dodecylstyrene, 3-methyl-5-n-hexylstyrene, 4-phenylstyrene, 2-ethyl-4-benzylstyrene, 3,5-diphenylstyrene, 2,3,4,5-tetraethylstyrene, 3-ethyl-1-vinylnaphthalene, 6-isopropyl-1-vinylnaphthalene, 6-cyclohexyl-1-vinylnaphthalene, 7-dodecyl-2-vinylnaphthalene and α-methylstyrene.More preferably, the vinyl aromatic monomer is selected from styrene, 3-methylstyrene and α-methylstyrene.In particular, the vinyl aromatic monomer used according to the present invention is styrene.

[0043] In a second aspect, the present invention relates to a method for the preparation of a copolymer of a conjugated diene monomer and a vinyl aromatic monomer, the method comprising the steps of: (1) to initiate anionic copolymerization, a monomer component comprising (i) one or more conjugated diene monomers and (ii) one or more vinyl aromatic monomers, a) an initiator component comprising one or more alkali metal salt derivatives and b) an initiator component having the following formula (I):

[0044] [ka]

[0045] [In the formula, R 1 , R 3 , and R 5 each is independently an alkyl, alkenyl, cycloalkyl, cycloalkenyl, or aryl group, or a combination thereof; R 1 , R 3 , and R 5 each having 1 to 20 carbon atoms, And R 2 , R 4 , and R 6 is independently H, an alkyl, alkenyl, cycloalkyl, cycloalkenyl, or aryl group, or a combination thereof; 2 , R 4 , and R 6 may each have up to 20 carbon atoms. and b) optionally with one or more further polar additives selected from the group of Lewis bases and Lewis acids; (2) continuously carrying out the copolymerization; (3) optionally coupling; Includes.

[0046] Further details of methods for the preparation of copolymers of conjugated diene monomers and vinyl aromatic monomers are provided in US Pat. No. 8,927,644 B2, the disclosure of which is incorporated herein by reference.

[0047] Preferably, the coupling agent is a tin halide coupling agent or a silicon halide coupling agent. More preferably, the silicon halide coupling agent is silicon tetrachloride, silicon tetrabromide, silicon tetrafluoride, silicon tetraiodide, hexachlorodisilane, hexabromodisilane, hexafluorodisilane, hexaiododisilane, octachlorotrisilane, octabromotrisilane, octafluorotrisilane, octaiodotrisilane, hexachlorodisiloxane, 2,2,4,4,6,6-hexachloro-2,4,6-trisilaheptane, 1,2,3,4,5,6-hexakis[2-(methyldichlorosilyl)ethyl]benzene, and a compound represented by the general formula (III): R 7 n -Si-X 4-n (III) [In the formula, R 7 is a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, n is an integer from 0 to 2, and X is a chlorine, bromine, fluorine, or iodine atom. The alkyl silicon halides are selected from the group consisting of:

[0048] The proportion of units having a star structure is from 0% by weight to 75% by weight of the copolymer of the present invention. According to a third aspect, the present invention relates to a copolymer based on a conjugated diene monomer and a vinyl aromatic monomer, the copolymer comprising (a) a vinyl aromatic monomer content of about 30 to about 80 weight percent, based on the total weight of the polymer; (b) a content of vinyl aromatic monomer blocks having more than 4 repeat units of about 0.01 to about 32 weight percent, based on the total vinyl aromatic monomer content; and (c) a vinyl content of greater than 8 to about 45 weight percent, based on the total conjugated diene polymerization fraction; has.

[0049] The copolymer preferably has a vinyl aromatic monomer content of from about 35 to about 65 weight percent, preferably from about 40 to about 55 weight percent, based on the total weight of (a) the polymer.

[0050] The copolymers preferably have a content of (b) vinyl aromatic monomer blocks having more than 4 repeat units of about 0.05 to about 18 weight percent, more preferably about 0.1 to about 12 weight percent, especially about 0.1 to about 6 weight percent, for example, about 0.1 to about 3 weight percent, or about 0.1 to about 2.5 weight percent, each based on the total vinyl aromatic monomer content.

[0051] Further, the copolymers of the present invention preferably have (c) a vinyl content of from about 10 to about 35 weight percent, preferably from about 14 to about 30 weight percent, and especially from about 18 to about 27 weight percent, each based on the total conjugated diene polymerized fraction.

[0052] The copolymers of the present invention also preferably have a ratio Mw / Mn of the uncoupled products in the range of about 1.01 to about 3.0, preferably in the range of about 1.01 to about 1.2. According to a fourth aspect, the present invention relates to a method for preparing a rubber comprising vulcanizing an elastomeric copolymer according to the third aspect in the presence of one or more vulcanizing agents, in which auxiliaries for crosslinking of the elastomeric copolymer (crosslinking agent) may be present, or auxiliaries for binding the rubber with fillers, or for better dispersion of the fillers, or for improving the chemical and / or physical properties of the rubber made from the elastomeric copolymer may be present. The particular crosslinking agents used are sulfur and sulfur donor compounds.

[0053] Furthermore, according to a fifth aspect, the present invention relates to a rubber obtainable according to the process of the fourth aspect. According to a sixth aspect, the present invention also relates to a rubber composition comprising a rubber component x) comprising a rubber according to the fifth aspect.

[0054] The rubber composition preferably further comprises y) one or more fillers, more preferably the fillers are selected from the group consisting of silica and carbon black, and most preferably the filler component y) comprises both silica and carbon black. The rubber composition can be used to produce highly reinforced rubber molded articles, mainly for the production of tires. The rubber composition of the present invention may further comprise other auxiliaries such as known accelerators, heat stabilizers, light stabilizers, antiozonants, antioxidants, processing aids, plasticizers, tackifiers, foaming agents, dyes, pigments, waxes, extenders, organic acids, retarders, metal oxides, and activators.

[0055] The fillers that can be used in the rubber composition include all known fillers used in the rubber industry. These include active fillers as well as inactive fillers. Examples are, for example, 10 to 1000 m 2 / g (BET and CTAB surface area), preferably 30 to 400 m 2 It is a particulate silica produced via precipitation from solutions of silicates or via flame hydrolysis of silicon halides, with a specific surface area of ​​1000 nm / g and a primary particle size of 10-1000 nm. Silica is, where relevant, a mixed oxide with other metal oxides, such as oxides of Al, Mg, Ca, Ba, Zn, Ti, or Zr; BET surface area is 20-400 m 2 synthetic silicates such as aluminum silicate or alkaline earth metal silicates (e.g. magnesium silicate or calcium silicate) having a particle size of 10 to 1000 nm / g and a primary particle size of 10 to 1000 nm; natural silicates such as kaolin and other naturally occurring forms of silica; metal oxides such as calcium oxide, zinc oxide, magnesium oxide, aluminum oxide; metal carbonates such as magnesium carbonate, calcium carbonate, zinc carbonate; metal hydroxides such as aluminum hydroxide or magnesium hydroxide; carbon blacks prepared by the flame black process, channel black process, furnace black process, gas black process, thermal black process, acetylene black process, or arc process, and having a BET surface area of ​​10 to 250 m2 / g, for example: conductive furnace (CF), superconducting furnace (SCF), super abrasion furnace (SAF), intermediate super abrasion furnace (ISAF), intermediate super abrasion furnace low structure (lSAF-LS), intermediate super abrasion furnace high modulus (ISAF-HM), intermediate super abrasion furnace low modulus (lSAF-LM), intermediate super abrasion furnace high structure (lSAF-HS), high abrasion furnace (HAF), high abrasion furnace low structure (HAP-LS), high abrasion furnace high structure (HAP-HS), fine furnace high structure (FF-HS), semi reinforced furnace (SRF), conductive furnace (extra conductive) furnace)(XCF), high speed extrusion furnace (FEE), high speed extrusion furnace low structure (FEE-LS), high speed extrusion furnace high structure (FEE-HS), general purpose furnace (GPF), general purpose furnace high structure (GPF-HS), all-purpose furnace (APP), semi-reinforced furnace low structure (SRF-LS), semi-reinforced furnace low modulus (SRF-LM), semi-reinforced furnace high structure (SRF-HS), semi-reinforced furnace high modulus (SRF-H Carbon blacks may also take the form of medium heat (MT) and medium heat (MT) carbon blacks, or the following types according to the ASTM classification: N110, N219, N220, N231, N234, N242, N294, N326, N327, N330, N332, N339, N347, N351, N356, N358, N375, N472, N539, N550, N568, N650, N660, N754, N762, N765, N774, N787, and N990 carbon blacks.

[0056] The above fillers can be used alone or as a mixture. In a particularly preferred embodiment, the rubber comprises as further filler component a mixture of a light-coloured filler such as particulate silica and carbon black, where the mixing ratio (by weight) of the light-coloured filler to the carbon black is 0.05:1 to 25:1, preferably 0.1:1 to 22:1. The amount of filler typically ranges from 10 to 500 parts by weight, based on 100 parts by weight of the rubber component x). It is preferred to use 10 to 200 parts by weight.

[0057] Preferably, the rubber composition according to the sixth embodiment has an amount of filler component y) in the range of 10 to 150 parts by mass (phr) per 100 parts by mass of rubber component x), more preferably the amount of component y) is 20 to 140 phr, and most preferably the amount of component y) is 30 to 130 phr.

[0058] It is also preferred that the rubber composition according to the sixth embodiment has a rubber component x) comprising one or more further rubbery polymers, more preferably the further rubbery polymer is selected from the group consisting of natural rubber, synthetic isoprene rubber, butadiene rubber, ethylene-α-olefin copolymer rubber, ethylene-α-olefin diene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber and halogenated butyl rubber.

[0059] The additional rubbery polymer may be a natural rubber or some synthetic rubber other than the rubber according to the fifth embodiment. The amount of the additional rubbery polymer usually ranges from 0.5 to 90% by weight, preferably from 10 to 70% by weight, based on the total amount of rubber in the rubber mixture. The amount of the additional rubbery polymer depends on the respective intended use of the rubber composition.

[0060] Further examples of rubbery polymers are natural rubber and synthetic rubber. Synthetic rubbers known from the literature are presented as examples. They are BR-polybutadiene, ABR-butadiene-C 1-4- alkyl acrylate copolymers, CR - polychloroprene, IR - polyisoprene, SBR - styrene-butadiene copolymers with a styrene content of 1 to 60% by weight, preferably 10 to 50% by weight, IIR - isobutylene-isoprene copolymers, NBR - butadiene-acrylonitrile copolymers with an acrylonitrile content of 3 to 60% by weight, preferably 15 to 40% by weight, HNBR - partially or fully hydrogenated NBR rubber, EPDM - ethylene-propylene-diene terpolymers, and mixtures of these further rubbery polymers. Materials of interest for the manufacture of automobile tires are more specifically natural rubber, emulsion SBR and solution SBR with a glass transition temperature above -100 ° C, polybutadiene rubber with a high cis content (> 90%) produced with catalysts based on Ni, Co, Ti or Nd, and polybutadiene rubber with a vinyl content of up to 85%, as well as mixtures of these.

[0061] According to a seventh aspect of the invention, a tire component comprises a rubber composition according to the sixth aspect. Preferably, the tire component is a tire tread. Finally, and according to an eighth aspect, a tire comprises the tire component of the seventh aspect.

[0062] In particular, the present invention relates to diene rubbers with a high styrene content and their use for the manufacture of rubber vulcanizates, which are useful in particular for the manufacture of highly reinforced rubber moldings, particularly preferably for the manufacture of tires, which have a particularly high wet skid resistance, a low rolling resistance when functionalized, and very good handling properties. The very high styrene content in the rubber of the present invention gives the rubber composition very good tensile properties as well as high tear resistance. Furthermore, the low content of styrene blocks avoids the creation of styrene domains in the rubber matrix.

[0063] The advantages of the present invention are particularly apparent from the following examples. EXAMPLES

[0064] Copolymer characterization Vinyl content (%) 600MHz based on BS ISO 21561:2005 1 H-NMR was used to measure.

[0065] Bound Styrene Content (%) 600MHz based on BS ISO 21561:2005 1 H-NMR was used to measure.

[0066] Block styrene content (%): 600MHz 1 H-NMR was used to measure. The content of block styrene consisting of six or more consecutive styrene units was determined according to the method reported by Y. Tanaka et al., Rubber Chemistry and Technology, 1981, 54, No. 4, 685-691, using the relative intensity of the ortho Ph-proton signal resonating above 6.7 ppm.

[0067] The content of block styrene consisting of four or more consecutive styrene units was determined using the relative intensity of the ortho Ph-proton signal resonating in the range 6.94-6 ppm according to the method described in DE 69712962.

[0068] The content of block styrene consisting of 4 to 6 consecutive units was calculated from the difference between both of the above block styrene contents. Molecular weight determination Gel permeation chromatography was performed using THF as eluent through a PSS Polymer Standards Service multicolumn (with guard column) for sample preparation. Multi-angle laser light scattering measurements were performed using a Wyatt Technologies Dawn® Heleos® II light scattering detector, a DAD (PDA) Agilent 1260 Infinity UV-VIS detector, and an Agilent 1260 Infinity refractive index detector.

[0069] Glass transition temperature (℃) Measured based on PN-EN ISO 11357-1:2009. Mooney Viscosity (ML 1+4, 100℃) Measurements were performed using an L rotor under the following conditions: preheating for 1 minute, rotor operation time for 4 minutes, and temperature at 100° C., based on ASTM D 1646-07.

[0070] Working Example All experiments were carried out with the same preparation method, but different reaction conditions were applied. polymerization Inactivation Step Cyclohexane (10 kg) was added to a nitrogen-purged 22 L reactor and treated with 2 g of a 1.6 M solution of n-butyllithium in cyclohexane. The solution was heated under reflux conditions (80-82 °C) and stirred vigorously for 10 minutes to clean and inertize the reactor. The solvent was then removed through the drain valve and purged again with nitrogen.

[0071] General Polymerization Procedure Cyclohexane was charged to the inerted reactor, followed by the addition of styrene and butadiene monomers, where the mass ratio of styrene to butadiene (ST / BD) depended on the desired styrene content (30-80 wt%). Next, 1,3,5-trimethylhexahydro-1,3,5-triazine (TMT) was introduced into the reactor to provide the desired content of styrene blocks (blockiness), where the molar ratio of TMT to initiator ranged from 0.01 to 50:1 depending on the total styrene content. The amounts of solvent, monomer, and additives were based on the scale of the reaction and are shown in Tables 1 and 2.

[0072] The solution in the reactor was heated and stirred continuously during the entire process. The temperature of the reaction mixture was kept between 60 and 90°C, where the exact temperature determined the content of vinyl units and partially influenced the blockiness of styrene units. Next, n-butyl lithium (BuLi) was added to start the polymerization process, where the exact amount of n-BuLi determined the molecular weight of the polymer. The reaction was carried out as an isothermal process for up to 120 minutes. The reaction solution was quenched using 2x molar amount of nitrogen purged isopropyl alcohol compared to n-butyl lithium and was quickly stabilized by the addition of 2-methyl-4,6-bis(octylsulfanylmethyl)phenol (at 1.0 phr polymer).

[0073] The polymer solution was transferred to a stripper. The reactor was flushed with a portion of fresh cyclohexane, the contents of which were also transferred to the stripper. Distilled water was added to the polymer solution in an amount twice the total mass of the polymer solution, and then the contents of the stripper were treated with steam. Steam stripping was carried out until the entire amount of cyclohexane was removed, yielding rubber crumbs. The rubber crumbs were then removed from the stripper, cooled to room temperature, crushed, and dried in a stream of hot air.

[0074] Details of the reaction conditions, recipes used, and properties of the resulting polymers are given in Tables 1 and 2. Examples 1-8 in Table 1 show the effect of increasing the content of TMT / n-BuLi, expressed as a molar ratio, on the formation of vinyl groups and styrene blockiness in HS-LV-SBR containing about 40% styrene. Examples 9-15 in Table 1 show the effect of a constant molar ratio of TMT / n-BuLi (about 5 / 1) on the styrene blockiness in UHS-LV-SBR containing 45% to 80% styrene.

[0075] Examples 16-21 in Table 2 show the effect of using a mixture of TMT and TMEDA on vinyl group formation and styrene blockiness in HS-LV-SBR containing about 40% styrene.

[0076] [Table 1]

[0077] [Table 2] The technical ideas that can be understood from the above-described embodiment will be described below as supplementary notes. [Appendix 1] The following formula (I): [ka] [In the formula, R 1 、R 3 , and R 5 each is independently an alkyl, alkenyl, cycloalkyl, cycloalkenyl, or aryl group, or a combination thereof; R 1 、R 3 , and R 5 each having 1 to 20 carbon atoms; And R 2 、R 4 , and R 6 is independently H, an alkyl, alkenyl, cycloalkyl, cycloalkenyl, or aryl group, or a combination thereof; 2 、R4 , and R 6 may each have up to 20 carbon atoms. 1. Use of an N,N',N''-substituted hexahydro-1,3,5-triazine having the formula: in the preparation of a copolymer of one or more conjugated diene monomers and one or more vinyl aromatic monomers, said preparation being by anionic polymerization in the presence of one or more anionic initiators, and said copolymer having a vinyl aromatic monomer content of about 35 to about 55 weight percent based on the total weight of the copolymer. [Appendix 2] the molar ratio of the hexahydro-1,3,5-triazine of formula (I) to the anionic initiator is in the range of 0.01 to 50; The use according to Appendix 1, wherein the ratio is more preferably in the range of 0.1 to 30. [Appendix 3] In the anionic polymerization, one or more additional polar modifiers are used, Preferably, the further polar modifier is selected from one or more of a Lewis base and a Lewis acid. [Appendix 4] the molar ratio of the additional polar modifier to the anionic initiator ranges from about 0.01 to about 50; The use according to appendix 3, wherein the ratio is preferably in the range of about 0.1 to about 10. [Appendix 5] the conjugated diene monomer is selected from 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 2,3-dimethyl-1,3-pentadiene, 2-phenyl-1,3-butadiene and 4,5-diethyl-1,3-octadiene; Preferably, the conjugated diene monomer is selected from 1,3-butadiene and isoprene; 5. The use according to any one of claims 1 to 4, in particular, wherein the conjugated diene monomer is 1,3-butadiene. [Appendix 6] the vinyl aromatic monomer is selected from styrene, 1-vinylnaphthalene, 3-methylstyrene, 3,5-diethylstyrene, 4-propylstyrene, 2,4,6-trimethylstyrene, 4-dodecylstyrene, 3-methyl-5-n-hexylstyrene, 4-phenylstyrene, 2-ethyl-4-benzylstyrene, 3,5-diphenylstyrene, 2,3,4,5-tetraethylstyrene, 3-ethyl-1-vinylnaphthalene, 6-isopropyl-1-vinylnaphthalene, 6-cyclohexyl-1-vinylnaphthalene, 7-dodecyl-2-vinylnaphthalene, and α-methylstyrene; Preferably, the vinyl aromatic monomer is selected from styrene, 3-methylstyrene, and α-methylstyrene; 6. The use according to any one of claims 1 to 5, in particular wherein the vinyl aromatic monomer is styrene. [Appendix 7] A process for the preparation of a copolymer of a conjugated diene monomer and a vinyl aromatic monomer, said process comprising the following steps to obtain said copolymer: (1) combining a monomer component comprising (i) one or more conjugated diene monomers and (ii) one or more vinyl aromatic monomers to initiate anionic copolymerization; a) an initiator component comprising one or more alkali metal salt derivatives, and b) an initiator component having the following formula (I):

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Claims

1. A copolymer based on a conjugated diene monomer and a vinyl aromatic monomer, said copolymer comprising: (a) a vinyl aromatic monomer content of 35 to 55 weight percent, based on the total weight of the polymer; (b) a content of vinyl aromatic monomer blocks having more than 4 repeat units of 0.01 to 12 weight percent, based on the total vinyl aromatic monomer content; and (c) having a vinyl content of greater than 8 to 35 weight percent, based on the total conjugated diene polymerization fraction; the vinyl aromatic monomer is selected from styrene, 1-vinylnaphthalene, 3-methylstyrene, 3,5-diethylstyrene, 4-propylstyrene, 2,4,6-trimethylstyrene, 4-dodecylstyrene, 3-methyl-5-n-hexylstyrene, 4-phenylstyrene, 2-ethyl-4-benzylstyrene, 3,5-diphenylstyrene, 2,3,4,5-tetraethylstyrene, 3-ethyl-1-vinylnaphthalene, 6-isopropyl-1-vinylnaphthalene, 6-cyclohexyl-1-vinylnaphthalene, 7-dodecyl-2-vinylnaphthalene, and α-methylstyrene; The content of the vinyl aromatic monomer block having more than 4 repeat units of (b) is 0.1 to 12 weight percent based on the total vinyl aromatic monomer content; and The vinyl content of said (c) is from 18 to 27 weight percent, based on the total conjugated diene polymerized fraction.

2. 10. The copolymer of claim 1, wherein the (a) vinyl aromatic monomer content is from 40 to 55 weight percent, based on the total weight of the polymer.

3. 2. The copolymer of claim 1, wherein the content of (b) vinyl aromatic monomer blocks having more than 4 repeat units is 0.1 to 6 weight percent based on the total vinyl aromatic monomer content.

4. 4. The copolymer of claim 3, wherein the content of (b) vinyl aromatic monomer blocks having more than 4 repeat units is 0.1 to 3 weight percent based on the total vinyl aromatic monomer content.

5. 5. The copolymer of claim 4, wherein the content of (b) vinyl aromatic monomer blocks having more than 4 repeat units is 0.1 to 2.5 weight percent based on the total vinyl aromatic monomer content.

6. A process for preparing a rubber comprising vulcanizing an elastomeric copolymer according to any one of claims 1 to 5 in the presence of one or more vulcanizing agents.

7. A rubber obtainable according to the process of claim 6.

8. A rubber composition comprising a rubber component x) containing the rubber according to claim 7.

9. The rubber composition of claim 8, further comprising y) one or more fillers.

10. 10. The rubber composition of claim 9, wherein said filler is selected from the group consisting of silica and carbon black.

11. 10. The rubber composition of claim 9, wherein said filler component comprises y) both silica and carbon black.

12. The rubber composition of any one of claims 9 to 11, wherein the amount of filler component y) is 10 to 150 parts by weight per 100 parts by weight of rubber component x) (phr).

13. The rubber composition of claim 12, wherein the amount of component y) is 20 to 140 phr per 100 parts by weight of rubber component x).

14. The rubber composition of claim 13, wherein the amount of component y) is 30 to 130 phr per 100 parts by weight of rubber component x).

15. The rubber composition according to any one of claims 8 to 14, wherein said rubber component x) also comprises one or more further rubbery polymers.

16. 16. The rubber composition of claim 15, wherein the additional rubbery polymer is selected from the group consisting of natural rubber, synthetic isoprene rubber, butadiene rubber, ethylene-α-olefin copolymer rubber, ethylene-α-olefin diene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, and halogenated butyl rubber.

17. A tire component comprising the rubber composition according to any one of claims 8 to 16.

18. 20. The tire component of claim 17, wherein the tire component is a tire tread.

19. A tire comprising a tire component according to claim 17 or claim 18.

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