Method for producing cyclic olefin copolymer

Abstract

To provide a method for producing a cyclic olefin copolymer which can efficiently produce a cyclic olefin copolymer by copolymerization of a norbornene monomer and a monomer containing ethylene while suppressing generation of polyethylene-like impurities.SOLUTION: A norbornene monomer and a monomer containing ethylene are polymerized in the presence of a metal-containing catalyst having a specific structure. As the metal-containing catalyst, a compound having a bond represented by M-A-Z is used. M is an atom of a Group 4 transition metal in the periodic table. A is an oxygen atom, a sulfur atom, a selenium atom or a tellurium atom. Z is a phenyl group having a substituent. In the phenyl group as Z, a hydrocarbon group which may contain a silicon atom or a germanium atom is bonded at the para position relative to the position where A is bonded.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a cyclic olefin copolymer containing structural units derived from a norbornene monomer and structural units derived from ethylene. [Background technology]

[0002] Cyclic olefin homopolymers and cyclic olefin copolymers have low moisture absorption and high transparency and are used in a variety of applications including optical materials such as optical disk substrates, optical films, and optical fibers. A typical cyclic olefin copolymer is a copolymer of cyclic olefin and ethylene, which is widely used as a transparent resin. The glass transition temperature (Tg) of the copolymer of cyclic olefin and ethylene can be changed depending on the copolymerization composition of the cyclic olefin and ethylene, and therefore it is possible to produce a copolymer with an adjustable glass transition temperature over a wide temperature range (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Incoronata, Tritto et al., Coordination Chemistry Reviews, 2006, Vol. 250, pp. 212-241 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a problem that a copolymer of a cyclic olefin and ethylene cannot be produced in high yield by the method described in Non-Patent Document 1. One possible solution to this problem is to carry out polymerization using a highly active catalyst. However, when polymerization is performed using a highly active catalyst in order to increase the production efficiency of cyclic olefin copolymers, polyethylene-like impurities may be easily produced. If polyethylene-like impurities are present in cyclic olefin copolymers, turbidity occurs when the cyclic olefin copolymer is dissolved in a solvent. As can be understood from this phenomenon, the presence of polyethylene-like impurities in cyclic olefin copolymers raises concerns about a decrease in the transparency of the cyclic olefin copolymer. Furthermore, if polyethylene-like impurities are produced, a process of filtering and removing the insoluble polyethylene-like impurities is required in the general production process for cyclic olefin copolymers, which increases production costs.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for producing a cyclic olefin copolymer, which can efficiently produce a cyclic olefin copolymer by copolymerizing a norbornene monomer and a monomer containing ethylene while suppressing the production of polyethylene-like impurities. [Means for solving the problem]

[0006] The present inventors have found that the above-mentioned problems can be solved by polymerizing a monomer containing a norbornene monomer and ethylene in the presence of a metal-containing catalyst having a specific structure, and have thus completed the present invention. More specifically, the present invention provides the following.

[0007] (1) A method for producing a cyclic olefin copolymer containing a structural unit derived from a norbornene monomer and a structural unit derived from ethylene, comprising the steps of: charging at least norbornene monomer and ethylene as monomers into a polymerization vessel; polymerizing the monomers in the polymerization vessel in the presence of a metal-containing catalyst; The metal-containing catalyst has a bond represented by MAZ, M is an atom of a transition metal of Group 4 of the periodic table; A is an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom; Z is a phenyl group having a substituent; A production method in which a hydrocarbon group which may contain a silicon atom or a germanium atom is bonded to the phenyl group at the para position relative to the position to which A is bonded.

[0008] (2) The metal-containing catalyst is represented by the following formula (a1): [ka] In formula (a1), M is Ti, Zr, or Hf, X is an organic substituent having 1 to 20 carbon atoms which may contain a heteroatom, or a halogen atom, and L 1 is the following formula (a1a): [ka] is a group represented by L 2 is expressed by the following formula (a1b): [ka] is a group represented by In formula (a1a), R a1 ~R a5 are each independently the same or different and are an organic or inorganic substituent having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom; R a1 ~R a5 two adjacent groups on the five-membered ring may be bonded to each other to form a ring; In formula (a1b), R a6 , and R a7 are each independently the same or different and are an organic or inorganic substituent having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom; R a8 is a hydrocarbon group which may contain a silicon atom or a germanium atom. A method for producing a cyclic olefin copolymer, wherein the metal-containing compound is represented by the formula:

[0009] (3)R a1 ~R a5(2) The method for producing a cyclic olefin copolymer according to (2), wherein at least one of the above is an organic substituent having 3 to 20 carbon atoms.

[0010] (4)R a1 ~R a5 is an organic substituent having 3 to 20 carbon atoms, and R a1 ~R a5 (3) The method for producing a cyclic olefin copolymer according to (3), wherein four of the groups are hydrogen atoms.

[0011] (5) The method for producing a cyclic olefin copolymer according to (4), wherein the organic substituent is a branched group.

[0012] (6) The method for producing a cyclic olefin copolymer according to any one of (1) to (5), wherein M is Ti.

[0013] (7) The method for producing a cyclic olefin copolymer according to any one of (1) to (6), wherein the total number of carbon atoms, silicon atoms, and germanium atoms contained in the hydrocarbon group which may contain a silicon atom or a germanium atom is 3 or more.

[0014] (8) The method for producing a cyclic olefin copolymer according to (7), wherein the hydrocarbon group which may contain a silicon atom or a germanium atom has a branch.

[0015] (9) The method for producing a cyclic olefin copolymer according to (8), wherein the hydrocarbon group which may contain a silicon atom or a germanium atom is a branched alkyl group, a dialkylsilyl group, or a trialkylsilyl group.

[0016] (10) A method for producing a cyclic olefin copolymer according to any one of (1) to (9), wherein the monomer is polymerized in the presence of a metal-containing catalyst and at least one of an aluminoxane and a borate compound.

[0017] (11) The method for producing a cyclic olefin copolymer according to any one of (1) to (10), wherein a DSC curve obtained by measuring a sample of the cyclic olefin copolymer using a differential scanning calorimeter under a nitrogen atmosphere at a heating rate of 20°C / min according to the method described in JIS K7121 does not show a melting point peak derived from polyethylene-like impurities within the range of 90°C to 140°C. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a method for producing a cyclic olefin copolymer, which can efficiently produce a cyclic olefin copolymer by copolymerizing a norbornene monomer and a monomer containing ethylene while suppressing the production of polyethylene-like impurities. DETAILED DESCRIPTION OF THE INVENTION

[0019] <Method for producing cyclic olefin copolymer> In the method for producing a cyclic olefin copolymer, a cyclic olefin copolymer containing structural units derived from a norbornene monomer and structural units derived from ethylene is produced. The manufacturing method includes: charging at least norbornene monomer and ethylene as monomers into a polymerization vessel; and polymerizing the monomers in a polymerization vessel in the presence of a metal-containing catalyst. Hereinafter, charging norbornene monomer and ethylene as monomers into a polymerization vessel is also referred to as a charging step, and polymerizing the monomers in the polymerization vessel in the presence of a metal-containing catalyst is also referred to as a polymerization step.

[0020] The monomers in the polymerization vessel are polymerized in the presence of a metal-containing catalyst having a predetermined structure, which will be described later. By using the metal-containing catalyst having a predetermined structure, which will be described later, in the copolymerization of norbornene monomer and ethylene, the yield of the cyclic olefin copolymer per unit weight of the catalyst can be increased.

[0021] Generally, when ethylene and norbornene monomers are copolymerized in the presence of a highly active catalyst, polymerization of ethylene units tends to proceed, and polyethylene-like impurities tend to be produced.

[0022] However, when a metal-containing catalyst having a specific structure, which will be described later, is used in polymerizing ethylene and norbornene monomer, it becomes easy to produce a cyclic olefin copolymer in a good yield while suppressing the formation of polyethylene-like impurities.

[0023] <Preparation process> In the charging step, norbornene monomer and ethylene are charged as monomers into a polymerization vessel. The polymerization vessel may also contain other monomers besides norbornene monomer and ethylene, as long as the object of the present invention is not impaired. In the cyclic olefin copolymer, the sum of the ratio of the constituent units derived from norbornene monomer and the ratio of the constituent units derived from ethylene is typically preferably 80% by mass or more, more preferably 95% by mass or more, and even more preferably 98% by mass or more, based on the total constituent units.

[0024] The monomer other than norbornene monomer and ethylene is not particularly limited as long as it is copolymerizable with norbornene monomer and ethylene. A typical example of such other monomer is an α-olefin. The α-olefin may be substituted with at least one substituent such as a halogen atom.

[0025] The α-olefin is preferably a C3 to C12 α-olefin. The C3 to C12 α-olefin is not particularly limited, but examples thereof include propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, and 1-dodecene. Of these, 1-hexene, 1-octene, and 1-decene are preferred.

[0026] The method of feeding ethylene into the polymerization solution is not particularly limited as long as the desired amount of ethylene can be charged into the polymerization vessel. Typically, ethylene is preferably charged into the polymerization vessel so that the ethylene charging pressure in the polymerization vessel is 0.5 MPa or higher. The ethylene charging pressure is more preferably 0.55 MPa or higher, and even more preferably 0.6 MPa or higher. Increasing the ethylene charging pressure can reduce the amount of catalyst used per polymer produced. The upper limit of the ethylene charging pressure is, for example, preferably 10 MPa or lower, more preferably 5 MPa or lower, and even more preferably 3 MPa or lower.

[0027] A solvent may be charged into the polymerization vessel together with the norbornene monomer and ethylene. The solvent is not particularly limited as long as it does not inhibit the polymerization reaction. Preferred solvents include, for example, hydrocarbon solvents such as aliphatic hydrocarbon solvents and aromatic hydrocarbon solvents, and halogenated hydrocarbon solvents. Hydrocarbon solvents are preferred because of their ease of handling, thermal stability, and chemical stability, and aliphatic hydrocarbon solvents are more preferred. Specific examples of preferred solvents include aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, isooctane, isododecane, mineral oil, cyclohexane, methylcyclohexane, and decahydronaphthalene (decalin); aromatic hydrocarbon solvents such as benzene, toluene, and xylene; and halogenated hydrocarbon solvents such as chloroform, methylene chloride, dichloromethane, dichloroethane, and chlorobenzene.

[0028] When the norbornene monomer is charged into the solvent, the concentration of the norbornene monomer is preferably, for example, 0.5% by mass or more as the lower limit, more preferably 10% by mass or more as the upper limit, and is preferably, for example, 50% by mass or less, more preferably 35% by mass or less as the upper limit.

[0029] The norbornene monomer will be described below.

[0030] [Norbornene monomer] Examples of norbornene monomers include norbornene and substituted norbornenes, and norbornene is preferred. The norbornene monomers can be used singly or in combination of two or more.

[0031] The substituted norbornene is not particularly limited, and examples of the substituents on the substituted norbornene include halogen atoms and monovalent or divalent hydrocarbon groups. Specific examples of the substituted norbornene include compounds represented by the following general formula (I):

[0032] [ka] (In the formula, R 1 ~R 12 may be the same or different and are selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group, R 9 and R 10 , R 11 and R 12 may combine together to form a divalent hydrocarbon group, R 9 or R 10 and R 11 or R 12 may form a ring together. Furthermore, n represents 0 or a positive integer, If n is 2 or more, R 5 ~R 8 may be the same or different in each repeating unit. However, if n=0, R 1 ~R 4 and R 9 ~R 12 At least one of the is not a hydrogen atom.)

[0033] The substituted norbornene represented by general formula (I) will be explained. R in general formula (I) 1 ~R 12 may be the same or different and are selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group.

[0034] R 1 ~R 8 Specific examples of include a hydrogen atom; a halogen atom such as fluorine, chlorine, or bromine; and an alkyl group having 1 to 20 carbon atoms, which may be different from each other, may be partially different, or may be the same as one another.

[0035] Also, R 9 ~R 12 Specific examples of the group include a hydrogen atom; a halogen atom such as fluorine, chlorine, or bromine; an alkyl group having 1 to 20 carbon atoms; a cycloalkyl group such as a cyclohexyl group; a substituted or unsubstituted aromatic hydrocarbon group such as a phenyl group, a tolyl group, an ethylphenyl group, an isopropylphenyl group, a naphthyl group, or an anthryl group; and an aralkyl group in which an aryl group is substituted on an alkyl group, such as a benzyl group or a phenethyl group. These may be different from each other, may be partially different, or may be the same as one another.

[0036] R 9 and R 10 , or R 11 and R 12 Specific examples of the divalent hydrocarbon group formed by combining with each other include alkylidene groups such as an ethylidene group, a propylidene group, and an isopropylidene group.

[0037] R 9 or R 10 and R 11 or R 12 When these rings form a ring, the ring formed may be a monocyclic ring or a polycyclic ring, a polycyclic ring having a bridge, a ring having a double bond, or a ring formed by a combination of these rings. In addition, these rings may have a substituent such as a methyl group.

[0038] Specific examples of the substituted norbornene represented by the general formula (I) include 5-methyl-bicyclo[2.2.1]hept-2-ene, 5,5-dimethyl-bicyclo[2.2.1]hept-2-ene, 5-ethyl-bicyclo[2.2.1]hept-2-ene, 5-butyl-bicyclo[2.2.1]hept-2-ene, 5-ethylidene-bicyclo[2.2.1]hept-2-ene, 5-hexyl- bicyclic olefins such as bicyclo[2.2.1]hept-2-ene, 5-octyl-bicyclo[2.2.1]hept-2-ene, 5-octadecyl-bicyclo[2.2.1]hept-2-ene, 5-methylidene-bicyclo[2.2.1]hept-2-ene, 5-vinyl-bicyclo[2.2.1]hept-2-ene, and 5-propenyl-bicyclo[2.2.1]hept-2-ene; Tricyclo[4.3.0.1 2,5 ]Deca-3,7-diene (common name: dicyclopentadiene), tricyclo[4.3.0.1 2,5 ]dec-3-ene; tricyclo[4.4.0.1 2,5 ]undeca-3,7-diene or tricyclo[4.4.0.1 2,5 ]undeca-3,8-diene or partially hydrogenated products thereof (or adducts of cyclopentadiene and cyclohexene), tricyclo[4.4.0.1 2,5 ]undec-3-ene; three-ring cyclic olefins such as 5-cyclopentyl-bicyclo[2.2.1]hept-2-ene, 5-cyclohexyl-bicyclo[2.2.1]hept-2-ene, 5-cyclohexenylbicyclo[2.2.1]hept-2-ene, and 5-phenyl-bicyclo[2.2.1]hept-2-ene; Tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodec-3-ene (also simply called tetracyclododecene), 8-methyltetracyclo[4.4.0.1 2,5 .1 7,10 ]dodec-3-ene, 8-ethyltetracyclo[4.4.0.1 2,5 .1 7,10 ]dodec-3-ene, 8-methylidenetetracyclo[4.4.0.1 2,5 .1 7,10]dodec-3-ene, 8-ethylidenetetracyclo[4.4.0.1 2,5 .1 7,10 ]dodec-3-ene, 8-vinyltetracyclo[4,4.0.1 2,5 .1 7,10 ]dodec-3-ene, 8-propenyl-tetracyclo[4.4.0.1 2,5 .1 7,10 ] 4-ring cyclic olefins such as dodec-3-ene; 8-Cyclopentyl-tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodec-3-ene, 8-cyclohexyl-tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodec-3-ene, 8-cyclohexenyl-tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodec-3-ene, 8-phenyl-cyclopentyl-tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodec-3-ene; tetracyclo[7.4.1 3,6 .0 1,9 .0 2,7 ]tetradeca-4,9,11,13-tetraene (also known as 1,4-methano-1,4,4a,9a-tetrahydrofluorene), tetracyclo[8.4.1 4,7 .0 1,10 .0 3,8 ]pentadeca-5,10,12,14-tetraene (also known as 1,4-methano-1,4,4a,5,10,10a-hexahydroanthracene); pentacyclo[6.6.1.1 3,6 .0 2,7 .0 9,14 ]-4-Hexadecene, Pentacyclo[6.5.1.1 3,6 .0 2,7 .0 9,13 ]-4-pentadecene, pentacyclo[7.4.0.0 2,7 .1 3,6 .1 10,13 ]-4-pentadecene;Heptacyclo[8.7.0.1 2,9 .1 4,7 .1 11,17 .0 3,8 .0 12,16]-5-eicosene, heptacyclo[8.7.0.1 2,9 .0 3,8 .1 4,7 .0 12,17 .1 13,l6 ]-14-eicosene; and polycyclic olefins such as a tetramer of cyclopentadiene.

[0039] Among these, alkyl-substituted norbornenes (e.g., bicyclo[2.2.1]hept-2-ene substituted with one or more alkyl groups) and alkylidene-substituted norbornenes (e.g., bicyclo[2.2.1]hept-2-ene substituted with one or more alkylidene groups) are preferred, and 5-ethylidene-bicyclo[2.2.1]hept-2-ene (trivial name: 5-ethylidene-2-norbornene, or simply ethylidenenorbornene) is particularly preferred.

[0040] <Polymerization process> In the polymerization step, the monomers in a polymerization vessel are polymerized in the presence of the metal-containing catalyst described below. The temperature during polymerization is not particularly limited. In order to obtain a good yield of the cyclic olefin copolymer, the temperature during polymerization is preferably 20°C or higher, more preferably 30°C or higher, even more preferably 50°C or higher, even more preferably 60°C or higher, and particularly preferably 70°C or higher. The temperature during polymerization may be 80°C or higher. The upper limit of the temperature during polymerization is not particularly limited, and the upper limit of the temperature during polymerization may be, for example, 200°C or lower, 140°C or lower, or 120°C or lower.

[0041] As the metal-containing catalyst, a metal-containing compound having a bond represented by MAZ is used. M is an atom of a transition metal of Group 4 of the periodic table. A is an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom. Z is a phenyl group having a substituent. In the phenyl group, a hydrocarbon group which may contain a silicon atom or a germanium atom is bonded at the para position relative to the position to which A is bonded.

[0042] As the atom of a transition metal of Group 4 of the periodic table represented by M, Ti, Zr, and Hf are preferred, and Ti and Zr are more preferred.

[0043] A is an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom. Among these, A is preferably an oxygen atom or a sulfur atom, and more preferably an oxygen atom.

[0044] Z is a phenyl group having a substituent. In the phenyl group represented by Z, a hydrocarbon group which may contain a silicon atom or a germanium atom is bonded at the para position relative to the position to which A is bonded. Such a hydrocarbon group may contain two or more atoms selected from silicon atoms and germanium atoms, and the number of atoms selected from silicon atoms and germanium atoms in such a hydrocarbon group is preferably 0 to 2, more preferably 0 or 1.

[0045] The total number of carbon atoms, silicon atoms, and germanium atoms contained in the hydrocarbon group that may contain a silicon atom or a germanium atom is not particularly limited as long as the desired effect is not impaired. The total number of carbon atoms, silicon atoms, and germanium atoms contained in the hydrocarbon group which may contain a silicon atom or a germanium atom is preferably 3 or more, more preferably 3 or more and 20 or less, even more preferably 3 or more and 12 or less, and particularly preferably 3 or more and 8 or less.

[0046] The hydrocarbon group which may contain a silicon atom or a germanium atom, in which the total number of carbon atoms, silicon atoms, and germanium atoms contained in the hydrocarbon group which may contain a silicon atom or a germanium atom is 3 or more, preferably has a branched chain. Suitable examples of the branched hydrocarbon group which may contain a silicon atom or a germanium atom include a branched alkyl group, a dialkylsilyl group, a trialkylsilyl group, a diarylsilyl group, a triarylsilyl group, a dialkylgermyl group, a trialkylgermyl group, a diarylgermyl group, and a triarylgermyl group. Among these, branched alkyl groups, dialkylsilyl groups, trialkylsilyl groups, diarylsilyl groups, and triarylsilyl groups are preferred.

[0047] Preferred examples of branched alkyl groups include isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, sec-pentyl, and tert-pentyl groups. Specific examples of the dialkylsilyl group include a dimethylsilyl group, a diethylsilyl group, a methylethylsilyl group, a di-n-propylsilyl group, and a diisopropylsilyl group. Specific examples of the trialkylsilyl group include a trimethylsilyl group, a triethylsilyl group, a methyldiethylsilyl group, and a dimethylethylsilyl group. A specific example of the diarylsilyl group is a diphenylsilyl group. A specific example of the triarylsilyl group is a triphenylsilyl group.

[0048] The phenyl group represented by Z preferably has substituents at the 2- and 6-positions when the position to which A is bonded is the 1-position. There are no particular limitations on the substituents bonded to positions 2 and 6. As the substituents bonded to positions 2 and 6, organic substituents having 1 to 20 carbon atoms are preferred. When the organic substituent having 1 to 20 carbon atoms contains a heteroatom, the type of the heteroatom is not particularly limited as long as it does not impair the object of the present invention. Specific examples of the heteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a silicon atom, a selenium atom, and a halogen atom.

[0049] Examples of the organic substituent include alkyl groups having 1 to 20 carbon atoms; alkoxy groups having 1 to 20 carbon atoms; cycloalkyl groups having 3 to 20 carbon atoms; aliphatic acyl groups having 2 to 20 carbon atoms; benzoyl groups; α-naphthylcarbonyl groups; β-naphthylcarbonyl groups; aromatic hydrocarbon groups having 6 to 20 carbon atoms; aralkyl groups having 7 to 20 carbon atoms; monoalkylsilyl groups, dialkylsilyl groups, and trialkylsilyl groups having 1 to 20 carbon atoms; mono-substituted amino groups substituted with a hydrocarbon group having 1 to 20 carbon atoms; and di-substituted amino groups substituted with a hydrocarbon group having 1 to 20 carbon atoms.

[0050] Among these organic substituents, alkyl groups having 1 to 20 carbon atoms are preferred, alkyl groups having 3 to 12 carbon atoms are more preferred, and alkyl groups having 3 to 8 carbon atoms are even more preferred. The organic substituents bonded to the 2- and 6-positions of the phenyl group as Z are preferably branched chain alkyl groups having 3 to 20 carbon atoms, more preferably branched chain alkyl groups having 3 to 12 carbon atoms, and even more preferably branched chain alkyl groups having 3 to 8 carbon atoms. As the substituents bonded to the 2- and 6-positions as Z, an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a sec-pentyl group, and a tert-pentyl group are preferred, and an isopropyl group and a tert-butyl group are more preferred.

[0051] Specific examples of the phenyl group having a substituent as Z include 4-substituted phenyl groups such as a 4-methylphenyl group, a 4-ethylphenyl group, a 4-n-propylphenyl group, a 4-isopropylphenyl group, a 4-n-butylphenyl group, a 4-isobutylphenyl group, a 4-sec-butylphenyl group, a 4-tert-butylphenyl group, a 4-n-pentylphenyl group, a 4-isopentylphenyl group, a 4-neopentylphenyl group, a 4-sec-pentylphenyl group, a tert-pentylphenyl group, a 4-trimethylsilylphenyl group, and a 4-triethylsilylphenyl group; a 2,6-diisopropyl-4-methylphenyl group, a 2,6-diisopropyl-4-ethylphenyl group, a 2,6-diisopropyl-4-n-dipropylphenyl group, a 2,4,6-trimethylsilylphenyl group, and a 4-triethylsilylphenyl group; 2,6-diisopropyl-4-substituted phenyl groups such as a 2,6-diisopropyl-4-n-butylphenyl group, a 2,6-diisopropyl-4-isobutylphenyl group, a 2,6-diisopropyl-4-sec-butylphenyl group, a 2,6-diisopropyl-4-tert-butylphenyl group, a 2,6-diisopropyl-4-n-pentylphenyl group, a 2,6-diisopropyl-4-isopentylphenyl group, a 2,6-diisopropyl-4-neopentylphenyl group, a 2,6-diisopropyl-4-sec-pentylphenyl group, a 2,6-diisopropyl-tert-pentylphenyl group, a 2,6-diisopropyl-4-trimethylsilylphenyl group, and a 2,6-diisopropyl-4-triethylsilylphenyl group;2,6-di-tett-butyl-4-methylphenyl group, 2,6-di-tett-butyl-4-ethylphenyl group, 2,6-di-tett-butyl-4-n-propylphenyl group, 2,6-di-tett-butyl-4-isopropylphenyl group, 2,6-di-tett-butyl-4-n-butylphenyl group, 2,6-di-tett-butyl-4-isobutylphenyl group, 2,6-di-tett-butyl-4-sec-butylphenyl group, 2,4,6-tri-tett-butylphenyl group, ...isopropylphenyl group, 2,6-di-tert-butyl-4-substituted phenyl groups such as 2,6-di-tett-butyl-4-n-pentylphenyl group, 2,6-di-tett-butyl-4-isopentylphenyl group, 2,6-di-tett-butyl-4-neopentylphenyl group, 2,6-di-tett-butyl-4-sec-pentylphenyl group, 2,6-di-tett-butyl-tert-pentylphenyl group, 2,6-di-tett-butyl-4-trimethylsilylphenyl group, and 2,6-di-tett-butyl-4-triethylsilylphenyl group;

[0052] The metal-containing catalyst is preferably a compound represented by the following formula (a1). [ka] In formula (a1), M is Ti, Zr, or Hf, X is an organic substituent having 1 to 20 carbon atoms which may contain a heteroatom, or a halogen atom, and L 1 is the following formula (a1a): [ka] is a group represented by L 2 is expressed by the following formula (a1b): [ka] is a group represented by In formula (a1a), R a1 ~R a5R may be the same or different and are independently an organic or inorganic substituent having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom. a1 ~R a5 two adjacent groups on the five-membered ring may be bonded to each other to form a ring; In formula (a1b), R a6 , and R a7 R may be the same or different and are independently an organic or inorganic substituent having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom. a8 is a hydrocarbon group which may contain a silicon atom or a germanium atom.

[0053] In formula (a1), M is Ti, Zr, or Hf, with Ti being particularly preferred in terms of the availability and ease of production of metal-containing catalysts, catalytic activity, and the like.

[0054] In formula (a1), X is an organic substituent having 1 to 20 carbon atoms which may contain a heteroatom, or a halogen atom. Regarding the organic substituent having 1 to 20 carbon atoms which may contain a heteroatom, when the organic substituent contains a heteroatom, the type of the heteroatom is not particularly limited as long as it does not impair the object of the present invention. Specific examples of the heteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a silicon atom, a selenium atom, and a halogen atom.

[0055] The organic substituent is not particularly limited as long as it does not inhibit the reaction for producing the metal-containing compound represented by the above formula (a1). Examples include an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aliphatic acyl group having 2 to 20 carbon atoms, a benzoyl group, an α-naphthylcarbonyl group, a β-naphthylcarbonyl group, an aromatic hydrocarbon group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a monoarylsilyl group, a diarylsilyl group, and a triarylsilyl group having 6 to 20 carbon atoms, a monoalkylsilyl group, a dialkylsilyl group, and a trialkylsilyl group having 1 to 20 carbon atoms, a mono-substituted amino group substituted with a hydrocarbon group having 1 to 20 carbon atoms, and a di-substituted amino group substituted with a hydrocarbon group having 1 to 20 carbon atoms.

[0056] Among these organic substituents, alkyl groups having 1 to 6 carbon atoms; alkoxy groups having 1 to 6 carbon atoms; cycloalkyl groups having 3 to 8 carbon atoms; aliphatic acyl groups having 2 to 6 carbon atoms; benzoyl groups; phenyl groups; benzyl groups; phenethyl groups; monoarylsilyl groups, diarylsilyl groups, and triarylsilyl groups having 6 to 20 carbon atoms; and monoalkylsilyl groups, dialkylsilyl groups, and trialkylsilyl groups having 1 to 20 carbon atoms are preferred.

[0057] Among the organic substituents, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, an isobutyloxy group, a sec-butyloxy group, a tert-butyloxy group, an acetyl group, a propionyl group, a butanoyl group, a phenyl group, a triphenylsilyl group, a trimethylsilyl group, a triethylsilyl group, and a tert-butyldimethylsilyl group are more preferred.

[0058] X is preferably a halogen atom, more preferably a chlorine atom or a bromine atom, and particularly preferably a chlorine atom.

[0059] In formula (a1a), Ra1 ~R a5 are each independently the same or different and are an organic or inorganic substituent having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom. a1 ~R a5 Two adjacent groups on the five-membered ring may be bonded to each other to form a ring. In formula (a1a), R a1 ~R a5 At least one of them is preferably an organic substituent having 3 to 20 carbon atoms. Also, R a1 ~R a5 is an organic substituent having 3 to 20 carbon atoms, and R a1 ~R a5 It is more preferred that four of the atoms are hydrogen atoms. R a1 ~R a5 The organic substituent as is preferably a branched group.

[0060] R a1 ~R a5 Specific examples and preferred examples of the organic substituent having 1 to 20 carbon atoms which may contain a heteroatom as X are the same as the specific examples and preferred examples of the organic substituent having 1 to 20 carbon atoms which may contain a heteroatom as X. R a1 ~R a5 Among the organic substituents as , an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a trimethylsilyl group, and a triethylsilyl group are preferred, and an isopropyl group, a tert-butyl group, a trimethylsilyl group, and a triethylsilyl group are more preferred.

[0061] The inorganic substituent is not particularly limited as long as it does not inhibit the reaction for producing the metal-containing compound represented by the above formula (a1). Specific examples of the inorganic substituent include a halogen atom, a nitro group, an unsubstituted amino group, and a cyano group.

[0062] In formula (a1b), R a6, and R a7 may be the same or different and independently represent an organic or inorganic substituent having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom. R in formula (a1b) a6 , and R a7 Specific examples and preferred examples of the organic substituent as Z are the same as the specific examples and preferred examples of the organic substituent bonded to the 2-position and 6-position of the phenyl group as Z, respectively. R in formula (a1b) a6 , and R a7 Specific and preferred examples of inorganic substituents as R a1 ~R a5 Specific examples and preferred examples of the inorganic substituent as the substituent are the same as those of the inorganic substituent as the ... inorganic substituent.

[0063] In formula (a1b), R a8 R is a hydrocarbon group which may contain a silicon atom or a germanium atom. a8 The hydrocarbon group as Z, which may contain a silicon atom or a germanium atom, is the same as the hydrocarbon group as Z, which may contain a silicon atom or a germanium atom, in the phenyl group as described above.

[0064] Preferred examples of the group represented by formula (a1b) include 4-substituted phenoxy groups such as 4-methylphenoxy group, 4-ethylphenoxy group, 4-n-propylphenoxy group, 4-isopropylphenoxy group, 4-n-butylphenoxy group, 4-isobutylphenoxy group, 4-sec-butylphenoxy group, 4-tert-butylphenoxy group, 4-n-pentylphenoxy group, 4-isopentylphenoxy group, 4-neopentylphenoxy group, 4-sec-pentylphenoxy group, tert-pentylphenoxy group, 4-trimethylsilylphenoxy group, and 4-triethylsilylphenoxy group; 2,6-diisopropyl-4-methylphenoxy group, 2,6-diisopropyl-4-ethylphenoxy group, 2,6-diisopropyl-4-n-dipropylphenoxy group, 2,4,6- 2,6-diisopropyl-4-substituted phenoxy groups such as a triisopropylphenoxy group, a 2,6-diisopropyl-4-n-butylphenoxy group, a 2,6-diisopropyl-4-isobutylphenoxy group, a 2,6-diisopropyl-4-sec-butylphenoxy group, a 2,6-diisopropyl-4-tert-butylphenoxy group, a 2,6-diisopropyl-4-n-pentylphenoxy group, a 2,6-diisopropyl-4-isopentylphenoxy group, a 2,6-diisopropyl-4-neopentylphenoxy group, a 2,6-diisopropyl-4-sec-pentylphenoxy group, a 2,6-diisopropyl-tert-pentylphenoxy group, a 2,6-diisopropyl-4-trimethylsilylphenoxy group, and a 2,6-diisopropyl-4-triethylsilylphenoxy group;2,6-di-tett-butyl-4-methylphenoxy group, 2,6-di-tett-butyl-4-ethylphenoxy group, 2,6-di-tett-butyl-4-n-propylphenoxy group, 2,6-di-tett-butyl-4-isopropylphenoxy group, 2,6-di-tett-butyl-4-n-butylphenoxy group, 2,6-di-tett-butyl-4-isobutylphenoxy group, 2,6-di-tett-butyl-4-sec-butylphenoxy group, 2,4,6-tri-tett-butylphenoxy group, 2,6-di-tett-butyl 2,6-di-tert-butyl-4-substituted phenoxy groups such as 2,6-di-tett-butyl-4-n-pentylphenoxy group, 2,6-di-tett-butyl-4-isopentylphenoxy group, 2,6-di-tett-butyl-4-neopentylphenoxy group, 2,6-di-tett-butyl-4-sec-pentylphenoxy group, 2,6-di-tett-butyl-tert-pentylphenoxy group, 2,6-di-tett-butyl-4-trimethylsilylphenoxy group, and 2,6-di-tett-butyl-4-triethylsilylphenoxy group;

[0065] Preferred specific examples of the metal-containing compound represented by formula (a1) explained above include the following metal-containing compounds. Note that M in the following formulas is the same as M in formula (a1). In addition, in the following formulas, Si(Me)3 is a trimethylsilyl group, Si(Et)3 is a triethylsilyl group, i-Pr is an isopropyl group, n-Bu is an n-butyl group, and t-Bu is a tert-butyl group.

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] The polymerization of the monomer is preferably carried out in the presence of the metal-containing catalyst and a co-catalyst. The co-catalyst may be any compound generally used as a co-catalyst in olefin polymerization, without any particular limitation. Suitable examples of the co-catalyst include aluminoxanes and ionic compounds. In terms of favorable progress of the polymerization reaction, the polymerization of the monomer is preferably carried out using at least one of aluminoxanes and borate compounds as ionic compounds as the co-catalyst, and more preferably using aluminoxanes as the co-catalyst.

[0070] That is, it is preferable to polymerize the monomer in the presence of a metal-containing catalyst and at least one of an aluminoxane and a borate compound, and it is more preferable to polymerize the monomer in the presence of a metal-containing catalyst and an aluminoxane.

[0071] The above metal-containing catalyst is preferably mixed with an aluminoxane and / or an ionic compound to form a catalyst composition. Here, the ionic compound is a compound that generates a cationic transition metal compound by reaction with a metal-containing catalyst.

[0072] The catalyst composition is preferably prepared using a solution of a metal-containing catalyst. The solvent contained in the solution of the metal-containing catalyst is not particularly limited. Preferred solvents include aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, isooctane, isododecane, mineral oil, cyclohexane, methylcyclohexane, decahydronaphthalene (decalin), and mineral oil; aromatic hydrocarbon solvents such as benzene, toluene, and xylene; and halogenated hydrocarbon solvents such as chloroform, methylene chloride, dichloromethane, dichloroethane, and chlorobenzene.

[0073] The amount of solvent used is not particularly limited as long as a catalyst composition with desired performance can be produced. Typically, the solvent is used in an amount such that the concentration of the metal-containing catalyst, aluminoxane, and ionic compound is preferably 0.00000001 to 100 mol / L, more preferably 0.00000005 to 50 mol / L, and particularly preferably 0.0000001 to 20 mol / L.

[0074] When mixing the liquid containing the raw materials for the catalyst composition, the number of moles of the transition metal element in the metal-containing catalyst is M a and the number of moles of aluminum in the aluminoxane is M b1 The number of moles of the ionic compound is M b2 In this case, (M b1 +M b2 ) / M a It is preferable that the liquid containing the raw materials for the catalyst composition is mixed so that the value of is preferably 1 to 200,000, more preferably 5 to 100,000, and particularly preferably 10 to 80,000.

[0075] The temperature at which the liquid containing the raw materials for the catalyst composition is mixed is not particularly limited, but is preferably from -100 to 100°C, more preferably from -50 to 50°C.

[0076] The mixing of the metal-containing catalyst solution with the aluminoxane and / or ionic compound to prepare the catalyst composition may be carried out in an apparatus separate from the polymerization vessel before polymerization, or may be carried out in the polymerization vessel before or during polymerization.

[0077] The materials used in the preparation of the catalyst composition and the preparation conditions for the catalyst composition will be described below.

[0078] [Aluminoxane] As the aluminoxane, various aluminoxanes that have been conventionally used as cocatalysts in the polymerization of various olefins can be used without any particular limitation. Typically, the aluminoxane is an organic aluminoxane. In producing the catalyst composition, one aluminoxane may be used alone, or two or more aluminoxanes may be used in combination.

[0079] As the aluminoxane, alkylaluminoxanes are preferably used. Examples of alkylaluminoxanes include compounds represented by the following formula (b1-1) or (b1-2). The alkylaluminoxanes represented by the following formula (b1-1) or (b1-2) are products obtained by reacting trialkylaluminum with water.

[0080] [ka] (In formula (b1-1) and formula (b1-2), R represents an alkyl group having 1 to 4 carbon atoms, and n represents an integer of 0 to 40, preferably 2 to 30.)

[0081] Examples of alkylaluminoxanes include methylaluminoxane and modified methylaluminoxanes in which some of the methyl groups in methylaluminoxane have been replaced with other alkyl groups. For example, modified methylaluminoxanes having an alkyl group with 2 to 4 carbon atoms, such as an ethyl group, a propyl group, an isopropyl group, a butyl group, or an isobutyl group, as the alkyl group after substitution are preferred, and modified methylaluminoxanes in which some of the methyl groups have been replaced with isobutyl groups are particularly preferred. Specific examples of alkylaluminoxanes include methylaluminoxane, ethylaluminoxane, propylaluminoxane, butylaluminoxane, isobutylaluminoxane, methylethylaluminoxane, methylbutylaluminoxane, and methylisobutylaluminoxane, with methylaluminoxane and methylisobutylaluminoxane being preferred.

[0082] The alkylaluminoxane can be prepared by a known method. Alternatively, commercially available alkylaluminoxanes may be used. Examples of commercially available alkylaluminoxanes include MMAO-3A, ​​TMAO-200 series, TMAO-340 series, solid MAO (all manufactured by Tosoh Finechem Corporation), and methylaluminoxane solution (manufactured by Albemarle Corporation). It is more preferable to use alkylaluminoxanes other than solid MAO, as this can easily suppress the formation of polyethylene-like impurities.

[0083] [Ionic compounds] An ionic compound is a compound that produces a cationic transition metal compound upon reaction with a metal-containing catalyst. Such ionic compounds include the anion of tetrakis(pentafluorophenyl)borate, the dimethylphenylammonium cation ((CH3)2N(C6H5)H + ), amine cations with active protons such as (C6H5)3C + Ionic compounds containing ions such as trisubstituted carbonium cations, carborane cations, metal carborane cations, and ferrocenium cations containing a transition metal can be used.

[0084] A preferred example of the ionic compound is a borate. Specific preferred examples of the borate include tetrakis(pentafluorophenyl)trityl borate, dimethylphenylammonium tetrakis(pentafluorophenyl)borate, and N-methyldialkylammonium tetrakis(pentafluorophenyl)borate such as N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate and N-methyldin-normal-decylammonium tetrakis(pentafluorophenyl)borate.

[0085] Furthermore, in terms of facilitating the production of a cyclic olefin copolymer in a good yield, it is preferable to have one or more members selected from aluminoxane, aromatic compounds having one or more phenolic hydroxyl groups and one or more halogen atoms on the aromatic ring, and hindered phenols present in the polymerization vessel before the metal-containing catalyst or the catalyst composition containing the metal-containing catalyst is added. In the above aromatic compounds having a phenolic hydroxyl group and a halogen atom, the phenolic hydroxyl group and the halogen atom are bonded to the same aromatic ring, which may be a single ring or a condensed ring. Hindered phenols are phenols having a bulky substituent at at least one of the two adjacent positions to the phenolic hydroxyl group, such as alkyl groups other than methyl groups (e.g., isopropyl, isobutyl, sec-butyl, and tert-butyl), alkenyl groups, alkynyl groups, aryl groups, heterocyclic groups, alkoxy groups, aryloxy groups, substituted amino groups, alkylthio groups, and arylthio groups.

[0086] Specific examples of hindered phenols include 2,6-di-tert-butyl-p-cresol (BHT), 2,6-di-tert-butylphenol, 2-tert-butylphenol, 2-tert-butyl-p-cresol, 3,3',5,5'-tetra-tert-butyl-4,4'-dihydroxybiphenyl, 3,3',5,5'-tetra-tert-butyl-2,2'-dihydroxybiphenyl, 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 2,2'-methylenebis(6-tert-butyl-4-methylphenol), 4,4',4"-(1-methylpropanyl-3-ylidene)tris(6-tert-butyl-m-cresol), and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylmethyl)2,4,6-trimethylbenzene. Among these, 2,6-di-tert-butyl-p-cresol (BHT) and 2,6-di-tert-butylphenol are preferred because they have a small molecular weight and the desired effect of using a hindered phenol can be easily obtained by using a small amount. The hindered phenol reacts with the alkylaluminum compound in the polymerization system, thereby contributing to an increase in the yield of the cyclic olefin copolymer. For this reason, the hindered phenol is preferably used together with the alkylaluminum. The hindered phenol may also be mixed with the alkylaluminum in the polymerization reactor before use. The mixture obtained by mixing the alkylaluminum and the hindered phenol before polymerization may also be introduced into the polymerization reactor.

[0087] The aluminoxane is as explained in the method for producing the catalyst composition.

[0088] When the aluminoxane is added to the polymerization vessel before adding the metal-containing catalyst or the catalyst composition containing the metal-containing catalyst, the amount used is preferably 1 to 1,000,000 mol, more preferably 10 to 100,000 mol, in terms of the number of moles of aluminum in the aluminoxane per 1 mol of the metal-containing catalyst.

[0089] The polymerization is also preferably carried out in the presence of a metal-containing catalyst, an aluminoxane, and a hindered phenol, or in the presence of a metal-containing catalyst, an ionic compound, and a hindered phenol.

[0090] It is also preferred that the monomers in the polymerization vessel are polymerized in the presence of a metal-containing catalyst and an alkyl metal compound. The alkylmetal compound is not particularly limited as long as it is a compound that has been conventionally used in the polymerization reaction of olefins such as cyclic olefins. Suitable alkylmetal compounds include alkylaluminum compounds having at least one alkyl group bonded to an Al atom and alkylzinc compounds having at least one alkyl group bonded to a Zn atom. When the above-mentioned metal-containing catalyst and an alkyl metal compound are used in combination, it is particularly easy to efficiently produce a cyclic olefin copolymer by copolymerizing a norbornene monomer and a monomer containing ethylene while suppressing the production of polyethylene-like impurities.

[0091] The alkyl metal compounds may be used singly or in combination of two or more.

[0092] The alkylaluminum compound may be any compound conventionally used for the polymerization of olefins, etc., and includes, for example, compounds represented by the following general formula (II): (R 01 ) z1 AlX 3-z1 (II) (In formula (II), R 01 is an alkyl group having 1 to 15 carbon atoms, X is a halogen atom or a hydrogen atom, and z1 is an integer of 1 to 3.

[0093] R 01 The number of carbon atoms in the alkyl group as the alkyl group is 1 to 15, and from the viewpoint of easily achieving the desired effect, it is more preferably 1 to 8, and even more preferably 2 to 8. Specific preferred examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group.

[0094] Specific examples of alkylaluminum compounds include trialkylaluminums such as trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-sec-butylaluminum, tri-n-pentylaluminum, tri-n-hexylaluminum, tri-n-heptylaluminum, and tri-n-octylaluminum; dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, and diisobutylaluminum chloride; dialkylaluminum hydrides such as dimethylaluminum hydride, diethylaluminum hydride, di-n-propyldimethylaluminum hydride, diisopropyldimethylaluminum hydride, di-n-butylaluminum hydride, diisobutylaluminum hydride, di-sec-butylaluminum hydride, di-n-pentylaluminum hydride, di-n-hexylaluminum hydride, di-n-heptylaluminum hydride, and di-n-octylaluminum hydride; and dialkylaluminum alkoxides such as dimethylaluminum methoxide.

[0095] The alkylzinc compound may be any compound conventionally used for the polymerization of olefins, etc., and includes, for example, compounds represented by the following general formula (III): (R 02 ) z2 ZnX 2-z2 (III) (In formula (II), R 02 is an alkyl group having 1 to 15, preferably 1 to 8, carbon atoms, X is a halogen atom or a hydrogen atom, and z2 is an integer of 1 to 3.

[0096] R 02The number of carbon atoms in the alkyl group as the alkyl group is 1 to 15, and from the viewpoint of easily achieving the desired effect, it is more preferably 1 to 8, and even more preferably 2 to 8. Specific preferred examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group.

[0097] Specific examples of the alkylzinc compound include dialkylzincs such as dimethylzinc, diethylzinc, di-n-propylzinc, diisopropylzinc, di-n-butylzinc, diisobutylzinc, di-sec-butylzinc, di-n-pentylzinc, di-n-hexylzinc, di-n-heptylzinc, and di-n-octylzinc; alkylzinc halides such as methylzinc chloride, ethylzinc chloride, and isobutylzinc chloride; and alkylzinc hydrides such as methylzinc hydride, ethylzinc hydride, and isobutylzinc hydride.

[0098] Among the alkyl metal compounds, one or more compounds selected from the group consisting of trialkylaluminum, dialkylaluminum hydride, and dialkylzinc are preferred, and trialkylaluminum and / or dialkylaluminum hydride are more preferred.

[0099] The amount of alkyl metal compound used together with the metal-containing catalyst is preferably 1 to 500,000 moles, more preferably 10 to 50,000 moles, in terms of the number of moles of alkyl metal compound per mole of the metal-containing catalyst.

[0100] The polymerization conditions are not particularly limited as long as they allow a cyclic olefin copolymer having desired physical properties to be obtained, and known conditions can be used. The amount of the catalyst composition used is derived from the amount of the metal-containing compound used in its preparation. The amount of the catalyst composition used is preferably 0.000000001 to 0.005 mol, more preferably 0.00000001 to 0.0005 mol, in terms of the mass of the metal-containing compound used in its preparation, per 1 mol of norbornene monomer.

[0101] The polymerization time is not particularly limited, and the polymerization is carried out until a desired yield is achieved or the molecular weight of the polymer increases to a desired level. The polymerization time varies depending on the temperature, catalyst composition, and monomer composition, but is typically 0.01 to 120 hours, preferably 0.1 to 80 hours, and more preferably 0.2 to 10 hours.

[0102] It is preferred that at least a portion, and preferably all, of the catalyst composition be added continuously to the polymerization vessel. By continuously adding the catalyst composition, the cyclic olefin copolymer can be continuously produced, and the production cost of the cyclic olefin copolymer can be reduced.

[0103] According to the method described above, a norbornene monomer and a monomer containing ethylene are copolymerized to efficiently produce a cyclic olefin copolymer while suppressing the production of polyethylene-like impurities. The suppression of the formation of polyethylene-like impurities can be confirmed, for example, by visually observing a solution prepared by dissolving 0.1 g of a cyclic olefin copolymer sample in 10 g of toluene. If no turbidity is observed when the toluene solution is visually observed, the formation of polyethylene-like impurities has been suppressed. The glass transition temperature of the resulting cyclic olefin copolymer is not particularly limited, but from the viewpoint of processability, it is, for example, preferably 185°C or less, more preferably 160°C or less, even more preferably 130°C or less, even more preferably 120°C or less, and particularly preferably 100°C or less. Typically, when a sample of a cyclic olefin copolymer is measured using a differential scanning calorimeter under conditions of a nitrogen atmosphere and a heating rate of 20°C / min according to the method described in JIS K7121, a glass transition temperature derived from the cyclic olefin copolymer is observed in the range of 50°C to 250°C in the obtained DSC curve. Furthermore, when a sample of the cyclic olefin copolymer produced by the above method is measured by a differential scanning calorimeter (DSC) under a nitrogen atmosphere at a heating rate of 20°C / min according to the method described in JIS K7121, it is preferable that the obtained DSC curve does not have a peak of the melting point (melting enthalpy) due to polyethylene-like impurities. This means that the polyethylene-like impurities in the cyclic olefin copolymer are absent or extremely small. Note that when polyethylene-like impurities are contained in the cyclic olefin copolymer, the melting point peak due to the polyethylene-like impurities on the DSC curve is generally detected within the range of 90°C to 140°C.

[0104] The cyclic olefin copolymer produced by the above method has a low content of polyethylene-like impurities and is excellent in transparency, and is therefore particularly suitable for use in optical films or sheets, packaging films or sheets, and other applications where high transparency is required from the standpoints of optical functionality and aesthetics. [Example]

[0105] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0106] [Examples 1 to 16 and Comparative Examples 1 to 4] In producing the cyclic olefin resin composition, the following Cat. 1 to Cat. 9 metal-containing catalysts were used in the examples and comparative examples.

[0107] [ka]

[0108] In the examples and comparative examples, the following CC1 and CC2 were used as co-catalysts. CC1: N-methyldialkylammonium tetrakis(pentafluorophenyl)borate (alkyl: C14-C18 (average: C17.5) (Tosoh Finechem Co., Ltd.) CC2: 6.5 mass% (as Al atom content) MMAO-3A toluene solution ([(CH3) 0.7 (iso-C4H9) 0.3 AlO] n (Tosoh Finechem Co., Ltd., containing 6 mol% trimethylaluminum based on the total aluminum)

[0109] (Examples 1 to 8, Examples 10 to 16, and Comparative Examples 1 to 4 Decalin as a polymerization solvent and the amount of 2-norbornene listed in Table 1 were placed in a well-dried 150 mL stainless steel autoclave equipped with a stir bar. After heating the autoclave to a polymerization temperature of 90°C, a metal-containing catalyst solution was added so that the amount of metal-containing catalyst was 0.5 μmol. The metal-containing catalyst solution was prepared using decalin. Next, 0.93 μmol of cocatalyst CC1 was added. Next, ethylene pressure of 0.9 MPa was applied, and the polymerization initiation point was determined as 30 seconds after that. The total amount of the monomer solution immediately before the application of ethylene pressure was 80 mL. Fifteen minutes after the start of polymerization, the ethylene supply was stopped, and the pressure was carefully returned to normal pressure. The reaction was then terminated by adding isopropyl alcohol to the reaction solution. The polymerization solution was then poured into a mixed solvent of 300 mL of acetone, 200 mL of methanol or isopropyl alcohol, and 5 mL of hydrochloric acid to precipitate the copolymer. The copolymer was recovered by suction filtration, washed with acetone and methanol, and then vacuum-dried at 110°C for 12 hours to obtain a norbornene-ethylene copolymer. Table 1 shows the copolymer yield (kg) per 1 g of catalyst, calculated from the amount of catalyst used and the amount of copolymer obtained.

[0110] Example 9 To a well-dried 150 mL stainless steel autoclave equipped with a stirrer, decalin as a polymerization solvent and the amount of 2-norbornene shown in Table 1 were added. Then, 5000 μmol of the cocatalyst CC2 was added. After heating the autoclave to a polymerization temperature of 90°C, a metal-containing catalyst solution was added so that the amount of the metal-containing catalyst was 0.5 μmol. The metal-containing catalyst solution was prepared using decalin. Next, ethylene pressure of 0.9 MPa was applied, and the polymerization initiation time was 30 seconds. The total amount of the monomer solution immediately before the application of ethylene pressure was 80 mL. Fifteen minutes after the start of polymerization, the ethylene supply was stopped, and the pressure was carefully returned to normal pressure. The reaction was then terminated by adding isopropyl alcohol to the reaction solution. The polymerization solution was then poured into a mixed solvent of 300 mL of acetone, 200 mL of methanol or isopropyl alcohol, and 5 mL of hydrochloric acid to precipitate the copolymer. The copolymer was recovered by suction filtration, washed with acetone and methanol, and then vacuum-dried at 110°C for 12 hours to obtain a norbornene-ethylene copolymer. Table 1 shows the copolymer yield (kg) per 1 g of catalyst, calculated from the amount of catalyst used and the amount of copolymer obtained.

[0111] The glass transition temperature was measured and a turbidity test was carried out according to the following methods. The results of the glass transition temperature measurement and the turbidity test are shown in Table 1.

[0112] <Glass transition temperature (Tg)> The Tg of the cyclic olefin copolymer was measured by the DSC method (the method described in JIS K7121). DSC device: differential scanning calorimeter (PerkinElmer, DSC-8500) Measurement atmosphere: Nitrogen Measurement temperature range: 50-250℃ Temperature rise condition: 20°C / min In Table 1, ND indicates that no peak of the glass transition temperature derived from the cyclic olefin copolymer is detected on the DSC curve within the above measurement temperature range.

[0113] <Impurity thermal analysis> In the DSC curve obtained by measuring the glass transition temperature, the calorific value (mJ / mg) was calculated from the peak area of ​​the melting point due to polyethylene-like impurities observed in the range of 90°C to 140°C. The larger the calculated calorific value, the higher the content of polyethylene-like impurities. In Table 1, ND indicates that no melting point peak due to polyethylene-like impurities was detected on the DSC curve.

[0114] <Turbidity test> 0.1 g of the obtained cyclic olefin copolymer was dissolved in 10 g of toluene, and the presence or absence of turbidity in the solution was observed. If turbidity was observed, the cyclic olefin copolymer contained polyethylene-like impurities. If no turbidity was observed, the cyclic olefin copolymer did not contain polyethylene-like impurities. The presence or absence of turbidity is shown in Table 1.

[0115] [Table 1]

[0116] According to Examples 1 to 16, it is clear that by polymerizing norbornene monomer and ethylene in the presence of a metal-containing catalyst having a predetermined structure, it is possible to efficiently obtain a copolymer of norbornene and ethylene while suppressing the production of polyethylene-like impurities. On the other hand, Comparative Examples 1 to 4 show that when a metal-containing catalyst having a structure other than the predetermined structure is used, it is difficult to efficiently obtain a copolymer of norbornene and ethylene, and furthermore, ethylene-like impurities are likely to be produced. In Examples 1 to 16, no peak corresponding to the melting point was observed on the DSC curve obtained when Tg was measured, whereas in Comparative Examples 1 to 4, a peak corresponding to the melting point of the polyethylene-like impurity was observed on the DSC curve obtained when Tg was measured.

Claims

1. A method for producing a cyclic olefin copolymer containing a structural unit derived from a norbornene monomer and a structural unit derived from ethylene, comprising: charging at least the norbornene monomer and ethylene as monomers into a polymerization vessel; polymerizing the monomer in the polymerization vessel in the presence of a metal-containing catalyst; the metal-containing catalyst has a bond represented by M-A-Z, M is an atom of a transition metal of Group 4 of the periodic table, A is an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom, and Z is a phenyl group having a substituent; A production method in which a hydrocarbon group which may contain a silicon atom or a germanium atom is bonded to the phenyl group at a para position relative to the position to which A is bonded.

2. The metal-containing catalyst is represented by the following formula (a1): 【Chemistry 1】 In formula (a1), M is Ti, Zr, or Hf, X is an organic substituent having 1 to 20 carbon atoms which may contain a heteroatom, or a halogen atom, and L １ is the following formula (a1a): 【Chemistry 2】 is a group represented by L ２ is represented by the following formula (a1b): 【Transformation 3】 is a group represented by In formula (a1a), R ａ１ ~R ａ５ are each independently the same or different and are an organic or inorganic substituent having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom; R ａ１ ~R ａ５ two adjacent groups on the five-membered ring may be bonded to each other to form a ring; In formula (a1b), R ａ６ , and R ａ７ are each independently the same or different and are an organic or inorganic substituent having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom; R ａ８ is a hydrocarbon group which may contain a silicon atom or a germanium atom. The method for producing a cyclic olefin copolymer according to claim 1, wherein the metal-containing compound is represented by the formula:

3. The R ａ１ ~R ａ５ The method for producing a cyclic olefin copolymer according to claim 2, wherein at least one of the above is an organic substituent having 3 to 20 carbon atoms.

4. The R ａ１ ~R ａ５ is an organic substituent having 3 to 20 carbon atoms, ａ１ ~R ａ５ The method for producing a cyclic olefin copolymer according to claim 3, wherein four of the groups are hydrogen atoms.

5. The method for producing a cyclic olefin copolymer according to claim 4 , wherein the organic substituent is a branched group.

6. The method for producing a cyclic olefin copolymer according to any one of claims 1 to 5, wherein M is Ti.

7. The method for producing a cyclic olefin copolymer according to any one of claims 1 to 5, wherein the total number of carbon atoms, silicon atoms, and germanium atoms contained in the hydrocarbon group which may contain a silicon atom or a germanium atom is 3 or more.

8. The method for producing a cyclic olefin copolymer according to claim 7 , wherein the hydrocarbon group which may contain a silicon atom or a germanium atom has a branch.

9. 9. The method for producing a cyclic olefin copolymer according to claim 8, wherein the hydrocarbon group which may contain a silicon atom or a germanium atom is a branched alkyl group, a dialkylsilyl group, or a trialkylsilyl group.

10. The method for producing a cyclic olefin copolymer according to any one of claims 1 to 5, wherein the monomer is polymerized in the presence of the metal-containing catalyst and at least one of an aluminoxane and a borate compound.

11. The method for producing a cyclic olefin copolymer according to any one of claims 1 to 5, wherein a DSC curve obtained by measuring a sample of the cyclic olefin copolymer using a differential scanning calorimeter in a nitrogen atmosphere at a heating rate of 20°C / min according to the method described in JIS K7121 does not have a melting point peak derived from polyethylene-like impurities within a range of 90°C to 140°C.

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