Catalyst composition, polymer production method, polymer, rubber composition, and tire

Abstract

To provide a catalyst composition which has high selectivity for the 1,4 bond in polymerization using at least a conjugated diene compound as a monomer.SOLUTION: The catalyst composition comprises: a metal compound having a metal element M selected from among transition elements belonging to groups 4-12 in the periodic table and rare-earth elements, or a metal-containing compound that is a reaction product of the metal compound and a Lewis base; and a coordinating compound represented by the general formula (1) in the figure, where R1 is a heteroaromatic group having a hydroxy group, and R2 is an optionally substituted aromatic hydrocarbon group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a catalyst composition, a method for producing a polymer, a polymer, a rubber composition, and a tire. [Background technology]

[0002] Numerous proposals have been made for polymerization catalysts for conjugated diene compounds. Among them, polymerization catalysts capable of producing conjugated diene polymers with a high cis-1,4 bond content are particularly desired from the viewpoint of the durability of the resulting rubber products, and such catalysts have been studied.

[0003] For example, composite catalyst systems containing transition metal compounds such as nickel, cobalt, and titanium as the main component are known, and some of these have already been widely used industrially as polymerization catalysts for butadiene, isoprene, etc. (Patent Document 1, etc.) In order to achieve an even higher cis-1,4 bond content, composite catalyst systems consisting of rare earth element compounds and Group 1 to 3 organometallic compounds have been researched and developed, and highly stereospecific polymerization has been studied. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 37-8198 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, from the viewpoint of further improving the functionality and versatility of rubber products, the development of polymerization catalysts with high selectivity for 1,4 bonds (cis-1,4 bonds and trans-1,4 bonds) of conjugated diene compounds has also become important in recent years.

[0006] Therefore, an object of the present invention is to provide a catalyst composition that has high selectivity for 1,4 bonds when polymerizing at least a conjugated diene compound as a monomer. Another object of the present invention is to provide a method for producing a polymer, which can produce a polymer having a high amount of 1,4 bonds in units derived from a conjugated diene compound. Furthermore, the present invention has an object to provide a polymer produced by the method for producing a polymer, a rubber composition containing the polymer, and a tire using the rubber composition. [Means for solving the problem]

[0007] The gist and configuration of the present invention to solve the above problems is as follows.

[0008] The first catalyst composition of the present invention comprises a metal compound having a metal element M selected from rare earth elements and transition elements belonging to Groups 4 to 12 of the periodic table, or a metal-containing compound which is a reaction product of the metal compound with a Lewis base; The following general formula (1): [ka] [In the formula, R 1 is a heteroaromatic group having a hydroxyl group, and R 2 is an aromatic hydrocarbon group which may have a substituent; The present invention is characterized by comprising: The first catalyst composition of the present invention has high selectivity for 1,4 bonds when polymerizing at least a conjugated diene compound as a monomer.

[0009] The second catalyst composition of the present invention is a catalyst represented by the following general formula (2): [ka] wherein E is a heteroatom other than carbon and hydrogen, the ring containing E is a heteroaromatic ring, and R 2 is an aromatic hydrocarbon group which may have a substituent, M is a metal element selected from rare earth elements and transition elements belonging to groups 4 to 12 of the periodic table, and Q 1 and Q 2are each independently a functional group having an element selected from nitrogen, oxygen, sulfur, boron, and halogen. The second catalyst composition of the present invention has high selectivity for 1,4 bonds when polymerizing at least a conjugated diene compound as a monomer.

[0010] The catalyst composition is represented by the following general formula (3): YR 3 a R 4 b R 5 c ···(3) [wherein Y is a metal element belonging to Group 1, 2, 12 or 13 of the periodic table; R 3 and R 4 is a hydrogen atom or a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, or an aryloxy group, and R 5 is a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, or an aryloxy group, and R 3 , R 4 and R 5 may be the same or different, and a, b, and c are each independently 0 or 1; provided that when Y is a metal element selected from Group 1, a is 1 and b and c are 0; when Y is a metal element selected from Groups 2 and 12, a and b are 1 and c is 0; and when Y is a metal element selected from Group 13, a, b, and c are 1. In this case, the polymerization activity is further enhanced.

[0011] The catalyst composition preferably further contains an aluminoxane, in which case the polymerization active species can be efficiently generated.

[0012] The catalyst composition preferably further contains at least one of an ionic compound and a halogen compound, which can reduce the proportion of impurities contained in the produced polymer.

[0013] In the catalyst composition, the metal element M is preferably neodymium, which further improves the polymerization activity.

[0014] In the above catalyst composition (first catalyst composition), R in general formula (1) 1 The heteroaromatic group constituting the formula (I) is preferably a furyl group, a thienyl group, a pyridyl group, a benzofuryl group, a benzothienyl group, a quinolyl group, a pyrrolyl group, or an indolyl group, in which case the selectivity for 1,4 bonds can be further improved.

[0015] In the above catalyst composition (second catalyst composition), it is preferred that E in general formula (2) is nitrogen, oxygen, or sulfur, and the heteroaromatic ring is a 5- or 6-membered ring, or a condensed ring of the 5- or 6-membered ring with a benzene ring, in which case the selectivity for 1,4 bonds can be further improved.

[0016] In the catalyst composition, R in the general formula (1) or the general formula (2) 2 is preferably a phenyl group, naphthyl group or anthracenyl group which may have a substituent, in which case the selectivity for 1,4 bonds can be further improved.

[0017] The method for producing a polymer of the present invention is characterized by comprising a step of polymerizing at least a conjugated diene compound as a monomer in the presence of the above catalyst composition to obtain a polymer. According to the method for producing a polymer of the present invention, it is possible to obtain a polymer (conjugated diene polymer) having a high content of 1,4 bonds in units derived from a conjugated diene compound.

[0018] The polymer of the present invention is characterized by being produced by the above-mentioned method for producing a polymer. Such a polymer of the present invention has a high amount of 1,4 bonds.

[0019] The rubber composition of the present invention is characterized by containing the above polymer. The rubber composition of the present invention has excellent durability.

[0020] The tire of the present invention is characterized by using the above rubber composition. The tire of the present invention is excellent in durability. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a catalyst composition that has high selectivity for 1,4 bonds when polymerizing at least a conjugated diene compound as a monomer. Furthermore, according to the present invention, it is possible to provide a method for producing a polymer, which is capable of obtaining a polymer having a high amount of 1,4 bonds in units derived from a conjugated diene compound. Furthermore, according to the present invention, it is possible to provide a polymer produced by the method for producing a polymer, a rubber composition containing the polymer, and a tire using the rubber composition. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described. However, these descriptions are for the purpose of illustrating the present invention and are not intended to limit the present invention in any way.

[0023] (First catalyst composition) The first catalyst composition of the present invention comprises a metal compound having a metal element M selected from rare earth elements and transition elements belonging to Groups 4 to 12 of the periodic table, or a metal-containing compound which is a reaction product of the metal compound with a Lewis base; The following general formula (1): [ka] [In the formula, R 1 is a heteroaromatic group having a hydroxyl group, and R 2 is an aromatic hydrocarbon group which may have a substituent; The present invention is characterized by comprising:

[0024] The reason why the catalyst composition has high 1,4 bond selectivity is that in the catalyst composition, the nitrogen atom in the coordination compound and R 1 The heteroatom in the compound is bidentately coordinated to the metal atom of the metal-containing compound to form a complex. This provides the electronic state of the metal atom and a specific steric environment that is believed to favor high 1,4 bond selection.

[0025] <Metal-containing compounds> The metal-containing compound contained in the first catalyst composition is a metal compound having a metal element M selected from rare earth elements and transition elements belonging to Groups 4 to 12 of the periodic table, or a reaction product of the metal compound with a Lewis base. The metal-containing compound may be one type alone or a combination of two or more types.

[0026] Specific examples of the metal element M include lanthanoids (elements with atomic numbers 57 to 71), scandium (Sc), yttrium (Y), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and cadmium (Cd). Among these, from the viewpoint of further improving polymerization activity, yttrium (Y), neodymium (Nd), and gadolinium (Gd) are preferred as the metal element M, and neodymium (Nb) is more preferred. In this specification, the term "transition elements" includes elements belonging to Group 12 of the periodic table (zinc (Zn), cadmium (Cd), and mercury (Hg)).

[0027] Specific examples of metal compounds having a metal element M include compounds represented by the following general formula (4): M-(Q 1 )(Q 2 )(Q 3 ) ···(4) (wherein M is a metal element selected from rare earth elements and transition elements belonging to groups 4 to 12 of the periodic table; Q1 , Q 2 and Q 3 and each independently represent a functional group having an element selected from nitrogen, oxygen, sulfur, boron, and halogen. 1 , Q 2 and Q 3 are all bonded to a metal element M. The metal compound having the metal element M may be one type alone or a combination of two or more types.

[0028] In the above general formula (4), Q 1 , Q 2 or Q 3 When is a nitrogen-containing functional group, examples of the functional group include an amide group. Examples of the amide group include aliphatic amide groups such as a dimethylamide group, a diethylamide group, and a diisopropylamide group; aryl amide groups such as a phenylamide group, a 2,6-di-tert-butylphenylamide group, a 2,6-diisopropylphenylamide group, a 2,6-dineobentylphenylamide group, a 2-tert-butyl-6-isopropylphenylamide group, a 2-tert-butyl-6-neobentylphenylamide group, a 2-isopropyl-6-neobentylphenylamide group, and a 2,4,6-tert-butylphenylamide group; and bistrialkylsilylamide groups such as a bistrimethylsilylamide group. In particular, a bistrimethylsilylamide group is preferred from the viewpoint of solubility in aliphatic hydrocarbons. The above functional groups may be used alone or in combination of two or more.

[0029] In the above general formula (4), Q 1 , Q 2 or Q 3When is a functional group having oxygen, examples of the functional group include an alkoxy group, an acyloxy group, and an alkoxycarboxyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, and an isopropoxy group. Examples of the acyloxy group include an acetoxy group, a valeroyl group, and a pivaloxy group. The above functional groups may be used alone or in combination of two or more.

[0030] In the above general formula (4), Q 1 , Q 2 or Q 3 When is a functional group having sulfur, examples of the functional group include an alkylthio group, an alkylsulfonyl group, and an arylsulfonyl group. Examples of the alkylthio group include a methylthio group and an isopropylthio group. Examples of the alkylsulfonyl group include an isopropanesulfonyl group and a hexanesulfonyl group. Examples of the arylsulfonyl group include a phenylsulfonyl group. The above functional groups may be used alone or in combination of two or more.

[0031] In the above general formula (4), Q 1 , Q 2 or Q 3 When is a functional group having a halogen, examples of the functional group include a halogen group.

[0032] Examples of Lewis bases that can react with the metal compounds include tetrahydrofuran, diethyl ether, dimethylaniline, trimethylphosphine, lithium chloride, neutral olefins, neutral diolefins, etc. The Lewis bases may be used alone or in combination of two or more.

[0033] <Coordination compounds> The coordinating compound contained in the first catalyst composition is represented by the following general formula (1): [ka] [In the formula, R 1is a heteroaromatic group having a hydroxyl group, and R 2 is an aromatic hydrocarbon group which may have a substituent. As described above, the coordinating compound has a carbon-nitrogen double bond (imine skeleton). The heteroaromatic group refers to a group having a heteroaromatic ring.

[0034] R in general formula (1) 1 Examples of heteroatoms contained in include nitrogen (N), oxygen (O), and sulfur (S).

[0035] R in general formula (1) 1 The heteroaromatic ring constituting the formula (I) may be, for example, a 4-, 5-, 6- or 7-membered monocyclic ring, or may be a condensed ring of such a monocyclic ring with a benzene ring.

[0036] R in general formula (1) 1 From the viewpoint of further improving the selectivity of the 1,4 bond, the heteroaromatic group constituting the formula (I) is preferably a furyl group (heteroatom: O, 5-membered ring (monocyclic)), a thienyl group (heteroatom: S, 5-membered ring (monocyclic)), a pyridyl group (heteroatom: N, 6-membered ring (monocyclic)), a benzofuryl group (heteroatom: O, fused ring of a 5-membered ring and a benzene ring), a benzothienyl group (heteroatom: S, fused ring of a 5-membered ring and a benzene ring), a quinolyl group (heteroatom: N, fused ring of a 6-membered ring and a benzene ring), a pyrrolyl group (heteroatom: N, 5-membered ring (monocyclic)), or an indolyl group (heteroatom: N, fused ring of a 5-membered ring and a benzene ring). Among these, a pyridyl group or a quinolyl group is particularly preferred.

[0037] In addition, R in general formula (1) 1 The heteroaromatic group as has one or more hydroxyl groups (OH groups). In particular, the number of hydroxyl groups in the heteroaromatic group is preferably one, from the viewpoint of further improving the polymerization activity. In addition, from the viewpoint of further improving the selectivity of 1,4 bonds, R 1In the heteroaromatic group as defined above, it is preferred that a hydroxyl group be bonded to the carbon atom adjacent to the heteroatom (nitrogen, oxygen, sulfur, etc.).

[0038] R in general formula (1) 2 From the viewpoint of further improving the selectivity for 1,4 bonds, the aromatic hydrocarbon group constituting the formula (I) is preferably a phenyl group, a naphthyl group, or an anthracenyl group which may have a substituent, and among these, a phenyl group is particularly preferred.

[0039] R in general formula (1) 2 is preferably an aromatic hydrocarbon group having a substituent, from the viewpoint of further improving the selectivity of the 1,4 bond. Examples of the substituent include aliphatic hydrocarbon groups having 1 to 6 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, and a tert-butyl group. Furthermore, from the viewpoint of further improving the selectivity of the 1,4 bond, the number of substituents in the aromatic hydrocarbon group is preferably two or more, and more preferably three. Furthermore, the positions of the substituents in the aromatic hydrocarbon group are preferably ortho-positions (two positions in total) based on the bonding position with nitrogen shown in general formula (1), and more preferably ortho-positions and para-positions (three positions in total).

[0040] The amount of the metal-containing compound and the amount of the coordinating compound in the first catalyst composition are not particularly limited as long as they are effective amounts capable of exerting catalytic action, and can be adjusted appropriately.

[0041] (Second catalyst composition) The second catalyst composition of the present invention is a compound represented by the following general formula (2): [ka] wherein E is a heteroatom other than carbon and hydrogen, the ring containing E is a heteroaromatic ring, and R 2 is an aromatic hydrocarbon group which may have a substituent, M is a metal element selected from rare earth elements and transition elements belonging to groups 4 to 12 of the periodic table, and Q 1and Q 2 are each independently a functional group having an element selected from nitrogen, oxygen, sulfur, boron, and halogen. The complex compound may be a single type or a combination of two or more types.

[0042] The complex compound typically corresponds to the product obtained by reacting the metal-containing compound and the coordinating compound in the first catalyst composition. Therefore, the action and effect of the second catalyst composition are the same as those of the first catalyst composition. In addition, in general formula (2), the N atom and the heteroatom E in the heteroaromatic ring are coordinated to M.

[0043] The heteroatom E in general formula (2) is preferably nitrogen (N), oxygen (O), or sulfur (S) from the viewpoint of further improving the selectivity of the 1,4 bond. In addition, the heteroaromatic ring in general formula (2) is preferably a 5- or 6-membered ring, or a condensed ring of such a ring with a benzene ring from the viewpoint of further improving the selectivity of the 1,4 bond.

[0044] Suitable examples of the metal element M in the complex compound are the same as those described above for the metal-containing compound in the first catalyst composition. 1 and functional group Q 2 Preferred examples of the heteroaromatic ring having a hydroxyl group in the complex compound are the same as those described above for the metal compound represented by general formula (4) in the first catalyst composition. 1 The same applies as described above with respect to the heteroaromatic group having a hydroxyl group as the aromatic hydrocarbon group R 2 Suitable examples of the coordinating compound are the same as those described above for the first catalyst composition.

[0045] The amount of the complex compound in the second catalyst composition is not particularly limited as long as it is an effective amount for exerting catalytic activity, and can be adjusted appropriately.

[0046] (cocatalyst) The catalyst compositions (first and second catalyst compositions) may further contain a promoter, as desired. Examples of promoters include compounds represented by the general formula (3) described below, aluminoxanes, ionic compounds, and halogen compounds. The promoters may be used singly or in combination of two or more.

[0047] The catalyst composition is represented by the following general formula (3): YR 3 a R 4 b R 5 c ···(3) [wherein Y is a metal element belonging to Group 1, 2, 12 or 13 of the periodic table; R 3 and R 4 is a hydrogen atom or a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, or an aryloxy group, and R 5 is a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, or an aryloxy group, and R 3 , R 4 and R 5 may be the same or different, and a, b, and c are each independently 0 or 1; provided that when Y is a metal element selected from Group 1, a is 1 and b and c are 0; when Y is a metal element selected from Groups 2 and 12, a and b are 1 and c is 0; and when Y is a metal element selected from Group 13, a, b, and c are 1. It is preferable that the polymerization composition further contains a compound represented by the following formula (3). In this case, polymerization activity is further enhanced. The compound represented by formula (3) may be used alone or in combination of two or more.

[0048] In one embodiment, Y in general formula (3) is a metal element belonging to Group 13, particularly boron (B) or aluminum (Al). In another embodiment, Y in general formula (3) is a metal element belonging to Group 1, particularly lithium (Li).

[0049] R in general formula (3) 3 , R 4 and R 5 Examples of the hydrocarbon group include a methyl group, an ethyl group, a tert-butyl group, and a phenyl group.

[0050] R in general formula (3) 3 , R 4 and R 5 The hydrocarbon group, alkoxy group, or aryloxy group may be substituted with a substituent, such as a linear or branched alkyl group (e.g., methyl group, tert-butyl group), or a halogen atom (e.g., fluorine).

[0051] Specific examples of the compound represented by general formula (3) include tris(pentafluorophenyl)borane, trimethylaluminum, triethylaluminum, triisobutylaluminum, lithium 2,6-di-tert-butyl-4-methylphenoxide, bis(2,6-di-tert-butyl-4-methylphenoxy)methylaluminum, diisobutylaluminum hydride, etc. Among these, tris(pentafluorophenyl)borane, trimethylaluminum, triisobutylaluminum, lithium 2,6-di-tert-butyl-4-methylphenoxide, bis(2,6-di-tert-butyl-4-methylphenoxy)methylaluminum, and diisobutylaluminum hydride are preferred.

[0052] When the catalyst composition contains a compound represented by general formula (3), the molar ratio of the compound represented by general formula (3) to the metal element M in the metal-containing compound or complex compound (compound of general formula (3) / M) is, in a preferred embodiment, 2 or more, 5 or more, 10 or more, or 20 or more, and 10,000 or less, 5,000 or less, 1,000 or less, 300 or less, 250 or less, 100 or less, or 50 or less.

[0053] The catalyst composition preferably further contains an aluminoxane. This allows efficient generation of polymerization active species. The aluminoxane may be used alone or in combination of two or more.

[0054] Aluminoxanes are compounds obtained by contacting an organoaluminum compound with a condensing agent such as water. Examples of aluminoxanes include linear or cyclic aluminoxanes having a repeating unit represented by the general formula (-Al(R')O-). In the general formula, R' represents a hydrocarbon group having 1 to 10 carbon atoms, some of which may be substituted with halogen atoms and / or alkoxy groups. The degree of polymerization of the repeating unit is 5 or more in one embodiment and 10 or more in another embodiment.

[0055] Examples of R' include methyl, ethyl, propyl, isobutyl, etc. In one embodiment, R' is a methyl group.

[0056] Examples of organoaluminum compounds used as raw materials for aluminoxane include trialkylaluminums such as trimethylaluminum, triethylaluminum, and triisobutylaluminum, and mixtures thereof. In one embodiment, the organoaluminum compound is trimethylaluminum.

[0057] Commercially available aluminoxanes may also be used, such as MMAO and TMAO manufactured by Tosoh Finechem Corporation.

[0058] When the catalyst composition contains an aluminoxane, the molar ratio (Al / M) of Al in the aluminoxane to the metal element M in the metal-containing compound or complex compound is, for example, 1 to 10,000, preferably 10 or more, more preferably 20 or more, even more preferably 50 or more, and particularly preferably 80 or more; and preferably 5,000 or less, more preferably 1,000 or less, and even more preferably 500 or less.

[0059] The catalyst composition preferably further contains at least one of an ionic compound and a halogen compound, which can reduce the proportion of impurities contained in the produced polymer.

[0060] Examples of the ionic compound include N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate and trityl tetrakis(pentafluorophenyl)borate, which are described in JP 2014-019729 A. The ionic compound may be used alone or in combination of two or more.

[0061] When the catalyst composition contains an ionic compound, the molar ratio of the ionic compound to the metal element M in the metal-containing compound or complex compound (ionic compound / M) is, in a preferred embodiment, 0.1 or more, 0.5 or more, 1 or more, or 5 or more, and 10,000 or less, 5,000 or less, 1,000 or less, 100 or less, or 50 or less.

[0062] Examples of the halogen compound include organometallic halogen compounds such as ethylaluminum dichloride, ethylmagnesium chloride, butylmagnesium chloride, dimethylaluminum chloride, diethylaluminum chloride, sesquiethylaluminum chloride, etc. The halogen compounds may be used alone or in combination of two or more.

[0063] When the catalyst composition contains a halogen compound, the molar ratio of the halogen compound to the metal element M in the metal-containing compound or complex compound (halogen compound / M) is, in a preferred embodiment, 0.1 or more, 0.5 or more, 1 or more, 10 or more, or 20 or more, and 10,000 or less, 5,000 or less, 1,000 or less, 500 or less, 300 or less, or 100 or less.

[0064] (Polymer manufacturing method) The method for producing a polymer of the present invention is a method for producing a polymer using any of the above-mentioned catalyst compositions, and is characterized by including a step of polymerizing at least a conjugated diene compound as a monomer in the presence of the catalyst composition to obtain a polymer (hereinafter, this may be simply referred to as a polymerization step). According to such a method for producing a polymer of the present invention, a polymer (conjugated diene polymer) having a high 1,4 bond content in units derived from the conjugated diene compound can be obtained.

[0065] The monomer used in the method for producing a polymer of the present invention may be a conjugated diene compound alone, or a combination of a conjugated diene compound and another monomer. Examples of the other monomer include a compound having an ethylenically unsaturated double bond. The other monomer may be used alone or in combination of two or more.

[0066] Examples of conjugated diene compounds include 1,3-butadiene (butadiene), isoprene, 1,3-pentadiene, and 2,3-dimethylbutadiene. The conjugated diene compounds may be substituted or unsubstituted. In one embodiment, the conjugated diene compounds have 4 to 8 carbon atoms. The conjugated diene compounds may be used singly or in combination of two or more.

[0067] In one embodiment, the conjugated diene compound is at least one of 1,3-butadiene and isoprene, hi another embodiment, the conjugated diene compound is solely isoprene.

[0068] Examples of the compound having an ethylenically unsaturated double bond include a non-conjugated olefin compound and an aromatic vinyl compound. The compound having an ethylenically unsaturated double bond may be substituted or unsubstituted. The compound having an ethylenically unsaturated double bond may be used alone or in combination of two or more.

[0069] Examples of non-conjugated olefin compounds include acyclic non-conjugated olefin compounds such as ethylene, propylene, 1-butene, isobutene, 1-pentene, 1-hexene, 1-heptene, and 1-octene; and cyclic non-conjugated olefin compounds such as norbornene, 5-norbornene-2-methanol, and 5-norbornene-2-methyl acetate. In one embodiment, the non-conjugated olefin compound has 2 to 10 carbon atoms. One type of non-conjugated olefin may be used alone, or two or more types may be used in combination.

[0070] In one embodiment, the non-conjugated olefin compound is at least one selected from acyclic non-conjugated olefin compounds (i.e., linear non-conjugated olefin compounds and branched non-conjugated olefin compounds) and cyclic non-conjugated olefins. In another embodiment, the non-conjugated olefin compound is an α-olefin. Since an α-olefin has a double bond at the α-position of the olefin, it can be efficiently copolymerized with a conjugated diene compound.

[0071] In one embodiment, the non-conjugated olefin compound is one or more selected from the group consisting of ethylene, propylene, 1-butene, and norbornene. In another embodiment, the non-conjugated olefin compound is exclusively ethylene. In another embodiment, the non-conjugated olefin compound is exclusively norbornene.

[0072] Examples of aromatic vinyl compounds include styrene, alkylstyrene, halogenated alkylstyrene, etc. The aromatic vinyl compounds may be used alone or in combination of two or more.

[0073] The number of carbon atoms in the alkyl group of the alkylstyrene is, for example, 1 to 5. Examples of alkylstyrene include 4-methylstyrene, 3-methylstyrene, and p-tert-butylstyrene.

[0074] The number of carbon atoms in the alkyl group of the halogenated alkylstyrene is, for example, 1 to 5. Examples of the halogen in the halogenated alkylstyrene include fluorine, chlorine, bromine, and iodine. Examples of the halogenated alkylstyrene include 4-chloromethylstyrene and 3-chloromethylstyrene.

[0075] In one embodiment, the compound having an ethylenically unsaturated double bond is one or more selected from the group consisting of ethylene, norbornene, and 5-norbornene-2-methanol.

[0076] In the method for producing a polymer of the present invention, it is preferable to use only isoprene as a monomer. Also, in the method for producing a polymer of the present invention, it is preferable to use isoprene and ethylene as monomers. Even in the polymerization of such compounds, the polymerization activity is high and it is easy to produce a polymer.

[0077] In the polymerization step, the molar ratio (monomer / M) of the monomer to the metal element M in the metal-containing compound or complex compound may be adjusted as appropriate. From the viewpoints of increasing the activity, the molecular weight of the polymer, and the polydispersity (Mw / Mn), the molar ratio is, for example, preferably 100 or more, more preferably 200 or more, and even more preferably 300 or more.

[0078] The polymerization method is not particularly limited, and for example, coordination polymerization, solution polymerization (anionic polymerization), etc. Polymerization may be carried out by any conventionally known method, such as continuous polymerization, semi-continuous polymerization, or batch polymerization.

[0079] In the polymerization step, in addition to the monomer and catalyst composition, a polymerization solvent, a polymerization initiator, a polymerization terminator, a stabilizer, an extender oil, a modifier, etc. may be used within the scope of the present invention. Examples of the polymerization solvent include, but are not limited to, hydrocarbon solvents such as benzene, toluene, cyclohexane, hexane, and butene.

[0080] The polymerization temperature is not particularly limited and may be appropriately set depending on the type of monomer, the type of catalyst, the desired amount of 1,4 bonds, the number average molecular weight, the polydispersity index, the Mooney viscosity, etc. In one embodiment, the polymerization temperature may be, for example, −100 to 150° C.

[0081] The polymerization step may be carried out under an inert gas atmosphere such as nitrogen gas or argon gas.

[0082] In the method for producing a polymer of the present invention, in addition to the above-mentioned polymerization step, any of the steps conventionally known in the production of diene polymers and the like, such as a step of purifying raw materials and solvents; a step of recovering solvents and unreacted monomers; a step of dehydrating the polymer after polymerization; a drying step, and a packaging step, may be carried out.

[0083] (polymer) The polymer of the present invention is a polymer (which may be a copolymer) produced by the above-mentioned method for producing a polymer. The polymer of the present invention is produced by the above-mentioned method for producing a polymer and has a high amount of 1,4 bonds.

[0084] The molecular weight of the polymer is not particularly limited and can be adjusted appropriately. For example, the number average molecular weight (Mn) of the polymer is 10,000 to 100,000.

[0085] In one embodiment, the polymer is one or more selected from the group consisting of polybutadiene, synthetic polyisoprene, styrene-butadiene copolymer, ethylene-butadiene copolymer, ethylene-isoprene copolymer, butadiene-norbornene copolymer, isoprene-norbornene copolymer, butadiene-5-norbornene-2-methanol copolymer, and butadiene-5-norbornene-2-methyl acetate copolymer.

[0086] In the polymer of the present invention, the 1,4 bond content (the total of the cis-1,4 bond content and the trans-1,4 bond content) in the units derived from a conjugated diene compound (i.e., conjugated diene units) is, for example, 87% or more, 88% or more, 90% or more, 91% or more, or 92% or more.

[0087] (Rubber composition) The rubber composition of the present invention is characterized by containing the above polymer. The rubber composition of the present invention has excellent durability because it contains the above polymer. The polymer may be used alone or in combination of two or more.

[0088] The rubber composition of the present invention may or may not contain other rubber components in addition to the above polymer. Examples of other rubber components include natural rubber, synthetic isoprene rubber, butadiene rubber, styrene-butadiene rubber, butyl rubber, bromide of a copolymer of isobutylene and p-methylstyrene, halogenated butyl rubber, acrylonitrile butadiene rubber, chloroprene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, styrene-isoprene rubber, styrene-isoprene-butadiene rubber, isoprene-butadiene rubber, chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, polysulfide rubber, silicone rubber, fluororubber, and urethane rubber. The other rubber components may be used alone or in combination of two or more.

[0089] In addition to the polymer, the rubber composition of the present invention may contain, as appropriate, known additives that are compounded into rubber compositions. Examples of such additives include fillers such as carbon black and silica, vulcanizing agents, crosslinking agents, vulcanization accelerators, antioxidants, reinforcing agents, softeners, vulcanization aids, colorants, flame retardants, lubricants, foaming agents, plasticizers, processing aids, antioxidants, scorch inhibitors, ultraviolet inhibitors, antistatic agents, color inhibitors, and oils. These may be used alone or in combination of two or more.

[0090] The method for preparing the rubber composition of the present invention is not particularly limited, and known methods can be used. For example, the rubber composition can be obtained by kneading each component including the polymer using a kneading machine such as a Banbury mixer, a roll, or an internal mixer. Alternatively, the rubber composition can be prepared by mixing components other than the vulcanizing agent and vulcanization accelerator in a non-production (non-pro) stage, and then compounding and mixing the vulcanizing agent and vulcanization accelerator into the mixture in a production (pro) stage.

[0091] Rubber products obtainable using the rubber composition of the present invention are not particularly limited, but examples thereof include tires, conveyor belts, vibration-proof rubber, seismic isolation rubber, rubber crawlers, hoses, and foams.

[0092] The method for obtaining a rubber product using the rubber composition of the present invention is not particularly limited, and known methods can be used. The conditions for crosslinking or vulcanizing the rubber composition can be appropriately adjusted, for example, a temperature of 120 to 200°C and a heating time of 1 to 900 minutes.

[0093] (tire) The tire of the present invention is characterized by using the above rubber composition. The tire of the present invention has excellent durability because it uses the above rubber composition. The application portion of the rubber composition of the present invention in a tire is not particularly limited, but examples thereof include tread rubber, base tread rubber, sidewall rubber, side reinforcing rubber, and bead filler.

[0094] The method for manufacturing the tire is not particularly limited, and any known method can be used. [Example]

[0095] The present invention will be described in more detail below by way of examples, but these examples are intended to illustrate the present invention and are not intended to limit the present invention in any way.

[0096] Details of the materials used in the examples are as follows: ·Metal-containing compound (M1): General formula (4): M-(Q 1 )(Q 2 )(Q 3 ) ···(4) In the formula, M is neodymium (Nd), A is nitrogen, and Q 1 , Q 2 and Q 3 All of these are bistrimethylsilylamide groups ((TMS)2N-), a compound called Nd[N(TMS)2]3. Coordination compound (C1): A compound represented by the following formula (C1): (((2,6-diisopropylphenyl)imino)methyl-2-hydroxy-6pyridyne) [ka] Coordination compound (C2): A compound represented by the following formula (C2). (((2,4,6-trimethylphenyl)imino)methyl-2-hydroxy-6pyridyne) [ka]

[0097] (Preparation of catalyst composition) The metal-containing compound (M1) (0.01 mmol) was placed in an argon-purged Schlenk tube, and toluene (2 mL) was added to dissolve it. The mixture was heated to 40°C, and the coordinating compound (0.01 mmol) shown in Table 1, triisobutylaluminum (1 M hexane solution, 0.10 mL, 0.10 mmol, 10 eq) as a co-catalyst (compound represented by general formula (3)), and trityl tetrakis(pentafluorophenyl)borate (9.2 mg, 0.01 mmol) as a co-catalyst (ionic compound) were reacted for 30 minutes to obtain a catalyst composition.

[0098] (polymer production) Isoprene (4.0 mL, 4.00 mmol, 400 eq) was added as a monomer to the catalyst composition, and a polymerization reaction was carried out for the time shown in Table 1. After the reaction, the produced polymer (polyisoprene) was recovered by reprecipitation using hydrochloric acid, 2,6-di-tert-butyl-4-methylphenol (butylhydroxytoluene, BHT), and a methanol solution.

[0099] The yield and the yield of the polymer in each example were measured based on the methanol-insoluble portion. The 1,4 bond content and the 3,4 bond content of the obtained polyisoprene were measured. 1 H-NMR spectrum and 13 The results were calculated from the integral ratio of the C-NMR spectrum, etc. The results are shown in Table 1.

[0100] [Table 1]

[0101] Table 1 shows that in Examples 1 and 2, which used catalyst compositions containing a predetermined metal-containing compound and a coordinating compound, the amount of 1,4 bonds in the resulting polymers was higher than that in Comparative Example 1. In other words, by using a predetermined metal-containing compound and a coordinating compound in combination as catalyst components (or by using a product obtained by the reaction of these), it is possible to improve the selectivity of 1,4 bonds when polymerizing a conjugated diene compound as a monomer. [Industrial Applicability]

[0102] According to the present invention, it is possible to provide a catalyst composition that has high selectivity for 1,4 bonds when polymerizing at least a conjugated diene compound as a monomer. Furthermore, according to the present invention, it is possible to provide a method for producing a polymer, which is capable of obtaining a polymer having a high amount of 1,4 bonds in units derived from a conjugated diene compound. Furthermore, according to the present invention, it is possible to provide a polymer produced by the method for producing a polymer, a rubber composition containing the polymer, and a tire using the rubber composition.

Claims

1. A metal-containing compound which is a metal compound having a metal element M selected from lanthanoids (elements with atomic numbers 57 to 71), scandium (Sc), yttrium (Y), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), and mercury (Hg), or a reaction product of the metal compound with a Lewis base; The following general formula (1): 【Chemical 1】 [In the formula, R １ is a heteroaromatic group having a hydroxyl group, the heteroaromatic group being a furyl group, a thienyl group, a pyridyl group, a benzofuryl group, a benzothienyl group, a quinolyl group, a pyrrolyl group or an indolyl group, R ２ is a phenyl group, a naphthyl group, or an anthracenyl group which may have a substituent; A catalyst composition comprising:

2. The following general formula (2): 【Chemistry 2】 wherein E is a heteroatom other than carbon and hydrogen, the ring containing E is a heteroaromatic ring, and the heteroaromatic ring is a furyl group, a thienyl group, a pyridyl group, a benzofuryl group, a benzothienyl group, a quinolyl group, a pyrrolyl group, or an indolyl group; R ２ is a phenyl group, naphthyl group, or anthracenyl group which may have a substituent; M is a metal element selected from lanthanoids (elements with atomic numbers of 57 to 71), scandium (Sc), yttrium (Y), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), and mercury (Hg); Q １ and Q ２ are each independently a functional group having an element selected from nitrogen, oxygen, sulfur, boron, and halogen.

3. The following general formula (3): YR ３ ａ R ４ ｂ R ５ ｃ ・・・(3) [wherein Y is a metal element belonging to Group 1, 2, 12 or 13 of the periodic table; R ３ and R ４ is a hydrogen atom or a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, or an aryloxy group, and R ５ is a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, or an aryloxy group, and R ３ , R ４ and R ５ may be the same or different, and a, b, and c are each independently 0 or 1; provided that when Y is a metal element selected from said Group 1, a is 1 and b and c are 0; when Y is a metal element selected from said Groups 2 and 12, a and b are 1 and c is 0; and when Y is a metal element selected from said Group 13, a, b, and c are 1.

4. The catalyst composition according to any one of claims 1 to 3, further comprising an aluminoxane.

5. The catalyst composition according to any one of claims 1 to 4, further comprising at least one of an ionic compound and a halogen compound.

6. The catalyst composition according to claim 1, wherein the metal element M is yttrium, neodymium, or gadolinium.

7. 7. The catalyst composition according to claim 6, wherein the metal element M is neodymium.

8. R in general formula (1) １ The catalyst composition according to any one of claims 1 and 3 to 7, wherein the heteroaromatic group constituting the formula (I) is a pyridyl group or a quinolyl group.

9. 8. The catalyst composition according to claim 2, wherein E in general formula (2) is nitrogen, oxygen, or sulfur, and the heteroaromatic ring is a 5-membered ring or 6-membered ring, or a condensed ring of such a ring with a benzene ring.

10. R in the general formula (1) or the general formula (2) ２ The catalyst composition according to any one of claims 1 to 9, wherein is a phenyl group.

11. A method for producing a polymer, comprising a step of polymerizing at least a conjugated diene compound as a monomer in the presence of the catalyst composition according to any one of claims 1 to 10 to obtain a polymer.

12. A polymer produced by the method for producing a polymer according to claim 11.

13. A rubber composition comprising the polymer according to claim 12.

14. A tire comprising the rubber composition according to claim 13.

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