Method for producing cyclic olefin copolymer

Abstract

The present invention provides a method for producing a cyclic olefin copolymer, the method making it possible to produce a cyclic olefin copolymer that has a low glass transition temperature and contains a structural unit derived from a norbornene monomer and a structural unit derived from an olefin selected from ethylene and α-olefins. A metal-containing catalyst that satisfies specific parameters and has a structure in which one or more ligands are coordinated to a central metal is used when producing a norbornene copolymer by polymerizing monomers including a norbornene monomer and an olefin selected from ethylene and α-olefins while the norbornene monomer is in a molten state.

Description

Method for producing cyclic olefin copolymer

[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 an olefin selected from ethylene and an α-olefin.

[0002] 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 representative cyclic olefin copolymer is a copolymer of a cyclic olefin and ethylene, which is widely used as a transparent resin. The glass transition temperature (Tg) of a cyclic olefin and ethylene copolymer can be varied depending on the copolymerization composition of the cyclic olefin and ethylene, allowing the production of copolymers with glass transition temperatures adjusted over a wide temperature range (see, for example, Non-Patent Document 1).

[0003] In recent years, various industries, particularly the manufacturing industry, have been increasingly demanding sustainability. As a method for producing the above-mentioned cyclic olefin copolymer that can meet the demand for sustainability, a method for producing the cyclic olefin copolymer by polymerization using a molten cyclic olefin monomer as a solvent has been proposed (see, for example, Patent Document 1). Cyclic olefin copolymers are generally produced by polymerization in an organic solvent. However, the method described in Patent Document 1 does not require energy for recycling the organic solvent by a method such as distillation, and can reduce the amount of organic solvent to be discarded.

[0004] JP 04-268312

[0005] Incoronatta, Tritto et al., Coordination Chemistry Reviews, 2006, Vol. 250, pp. 212-241

[0006] However, as described in Patent Document 1, when a cyclic olefin copolymer is produced by carrying out polymerization in a molten cyclic olefin, it is difficult to obtain a cyclic olefin copolymer having a low glass transition temperature.

[0007] 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 produce a cyclic olefin copolymer containing structural units derived from a norbornene monomer and structural units derived from an olefin selected from ethylene and an α-olefin, and having a low glass transition temperature.

[0008] The present inventors have found that the above-mentioned problems can be solved by using a metal-containing catalyst having a structure in which one or more ligands are coordinated to a central metal and satisfying specific parameters when producing a norbornene copolymer by polymerizing a norbornene monomer and an olefin selected from ethylene and an α-olefin while the norbornene monomer is in a molten state, and have thus completed the present invention. More specifically, the present invention provides the following.

[0009] (1) A method for producing a cyclic olefin copolymer containing a structural unit derived from a norbornene monomer and a structural unit derived from an olefin selected from ethylene and an α-olefin, the method comprising: charging at least a norbornene monomer and an olefin as monomers into a polymerization vessel; and polymerizing the monomers in the polymerization vessel in a molten state of the norbornene monomer in the presence of a metal-containing catalyst having a structure in which one or more ligands are coordinated to a central metal, wherein the ratio of the mass of the norbornene monomer to the mass of the polymerization solution in the polymerization vessel at the start of polymerization is 80 mass% or more; and the monomer reactivity ratio r of the metal-containing catalyst at 1 atmosphere and a reaction temperature of 363.15 K is 0.05 mass% or more. Ｎ The value is 1.0 x 10 －４ is less than or equal to r Ｎ The value of k is the insertion rate constant of norbornene into norbornene bound to a metal-containing catalyst. ＮＮ and the insertion rate constant k of ethylene into norbornene bound to a metal-containing catalyst. ＮＥ Relative to k ＮＮ / k ＮＥ The value of r Ｎ is expressed by the following formula (r1): Ｎ =exp(-(G ‡ ＮＮ -G ‡ ＮＥ) / RT) ... (r1) (In formula (r1), G ‡ ＮＮ is the Gibbs free energy of activation of the insertion reaction of norbornene into norbornene bound to a metal-containing catalyst, and G ‡ ＮＥ is the Gibbs free energy of activation of the insertion reaction of ethylene into norbornene bound to a metal-containing catalyst, R is the gas constant, and T is the reaction temperature of 363.15 K. ‡ ＮＮ , and G ‡ ＮＥ is calculated by a density functional method based on the DFT theory M06-2X and the basis set cc-pVDZ-(PP), and the metal-containing catalyst contains Ti, Zr, Hf, Ni, Pd, or Pt as a central metal.

[0010] (2) The method for producing a cyclic olefin copolymer according to (1), wherein the polymerization solution in the polymerization vessel does not contain an organic solvent at the start of polymerization.

[0011] (3) The method for producing a cyclic olefin copolymer according to (1) or (2), wherein the polymerization pressure is 1 to 25 atmospheres as a gauge pressure when the metal-containing catalyst is added to the polymerization vessel.

[0012] (4) The method for producing a cyclic olefin copolymer according to any one of (1) to (3), wherein the polymerization of the monomers is carried out at 50 to 150°C.

[0013] (5) The method for producing a cyclic olefin copolymer according to any one of (1) to (4), wherein the polymerization of the monomers is carried out in the presence of one or more co-catalysts selected from aluminoxanes, alkyl metal compounds, borate compounds, and organic phosphine compounds.

[0014] (6) The method for producing a cyclic olefin copolymer according to any one of (1) to (5), wherein the polymerization of the monomers is carried out in the presence of a chain transfer agent.

[0015] (7) The method for producing a cyclic olefin copolymer according to (6), wherein the chain transfer agent is hydrogen or an amine.

[0016] According to the present invention, there can be provided a method for producing a cyclic olefin copolymer, which can produce a cyclic olefin copolymer containing structural units derived from a norbornene monomer and structural units derived from an olefin selected from ethylene and an α-olefin, and which has a low glass transition temperature.

[0017] <<Method for Producing Cyclic Olefin Copolymer>> The method for producing a cyclic olefin copolymer is a method for producing a cyclic olefin copolymer containing structural units derived from a norbornene monomer and structural units derived from an olefin selected from ethylene and an α-olefin.

[0018] The method for producing a cyclic olefin copolymer includes charging at least a norbornene monomer and an olefin as monomers into a polymerization vessel, and polymerizing the monomers in the polymerization vessel in a molten state of the norbornene monomer in the presence of a metal-containing catalyst having a structure in which one or more ligands are coordinated to a central metal.

[0019] At the start of polymerization, the ratio of the mass of the norbornene monomer to the mass of the polymerization solution in the polymerization vessel is 80 mass % or more.

[0020] <Metal-containing catalyst> Monomer reactivity ratio r of a metal-containing catalyst at 1 atmosphere and a reaction temperature of 363.15 K Ｎ The value is 1.0 x 10 －４ The following is true: Ｎ The value of k is the insertion rate constant of norbornene into norbornene bound to a metal-containing catalyst. ＮＮ and the insertion rate constant k of ethylene into norbornene bound to a metal-containing catalyst. ＮＥ Relative to k ＮＮ / k ＮＥ The value of r Ｎ is expressed by the following formula (r1): Ｎ =exp(-(G ‡ ＮＮ -G ‡ ＮＥ ) / RT) ... (r1) (In formula (r1), G ‡ ＮＮ is the Gibbs free energy of activation of the insertion reaction of norbornene into norbornene bound to a metal-containing catalyst, and G ‡ＮＥ is the Gibbs free energy of activation of the insertion reaction of ethylene into norbornene bound to a metal-containing catalyst, R is the gas constant, and T is the reaction temperature 363.15 K (90°C). ‡ ＮＮ , and G ‡ ＮＥ is calculated by density functional theory based on DFT theory M06-2X and basis set cc-pVDZ-(PP). The metal-containing catalyst contains Ti, Zr, Hf, Ni, Pd, or Pt as a central metal.

[0021] According to the above production method, a cyclic olefin copolymer having a low glass transition temperature can be produced. Specifically, the glass transition temperature of the resulting cyclic olefin copolymer is preferably 130°C or lower, more preferably 120°C or lower, and even more preferably 100°C or lower.

[0022] In the above production method, as described above, the monomer reactivity ratio r Ｎ The value of is 1.0 × 10 －４ A metal-containing catalyst is used which is: Ｎ The value of k is the insertion rate constant of norbornene into norbornene bound to a metal-containing catalyst. ＮＮ and the insertion rate constant k of ethylene into norbornene bound to a metal-containing catalyst. ＮＥ Relative to k ＮＮ / k ＮＥ The value of the monomer reactivity ratio r Ｎ The value of is 1.0 × 10 －４ By satisfying the above condition, continuous bonding of structural units derived from norbornene monomers during polymerization is suppressed, and a cyclic olefin copolymer having a low glass transition temperature can be produced.

[0023] The metal-containing catalyst may be selected from the group consisting of the above-mentioned r Ｎ By calculating (Cp)(ZR), the catalyst is selected from various metal-containing catalysts having a structure in which one or more ligands are coordinated to a central metal. The metal-containing catalyst is preferably selected from the group of metallocene catalysts represented by the following formula (C): ０１ ｍ )ｎ (A) ｒ ML ｐ (C)

[0024] In formula (C), (ZR ０１ ｎ１ ) ｎ２ is a divalent group that bonds Cp and A. Z is C, Si, Ge, N, or P. R ０１ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cycloalkenyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group having 7 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. Cp is a cyclopentadienyl group which may have a substituent and which may be condensed with an aromatic ring. A is -O-, -S-, -N(R ０２ )- or the aforementioned Cp. ０２ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cycloalkenyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group having 7 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. M is Ti, Zr, or Hf. L is a halogen atom, -OR ０３ , anionic sigma ligands selected from the group consisting of alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 1 to 20 carbon atoms, cycloalkyl groups having 3 to 20 carbon atoms, cycloalkenyl groups having 3 to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms, alkylaryl groups having 7 to 20 carbon atoms, and aralkyl groups having 7 to 20 carbon atoms. The anionic sigma ligand represented by L may contain one or more Si or Ge atoms. R ０３is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cycloalkenyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group having 7 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. n1 is 1 or 2. However, when Z is N or P, n1 is 1. When Z is C, Si, or Ge, n1 is 2. n2 is an integer from 0 to 4. r is 0 or 1. When r is 0, n2 is 0. p is an integer from 2 to 3. When r is 1, p is equal to (oxidation state of metal M - 2). When r is 0, p is equal to (oxidation state of metal M - 1).

[0025] is a divalent bridging group (ZR ０１ ｎ１ ) ｎ２ Suitable examples of -C(R ０１ ) ２ -, -(C(R ０１ ) ２ ) ２ -, -(C(R ０１ ) ２ ) ３ -, -Si(R ０１ ) ２ -, -Ge(R ０１ ) ２ -, -NR ０１ - and -PR ０１ - are some examples.

[0026] is a divalent bridging group (ZR ０１ ｎ１ ) ｎ２ Preferred examples of the group include —Si(CH ３ ) ２ -, -Si(Ph) ２ -, -CH ２ -, -CH ２ CH ２ -, -CH ２ CH ２ CH ２ -, and -C(CH ３ ) ２ - are some examples.

[0027] Preferred examples of the ligand Cp that is π-bonded to the metal M include a cyclopentadienyl group, a methylcyclopentadienyl group, a dimethylcyclopentadienyl group, a trimethylcyclopentadienyl group, and a tetramethylcyclopentadienyl group; a 4-tert-butylcyclopentadienyl group; a 4-adamantylcyclopentadienyl group; an indenyl group, a monomethylindenyl group, a dimethylindenyl group, a trimethylindenyl group, and a tetramethylindenyl group; a 4,5,6,7-tetrahydroindenyl group; a fluorenyl group; a 5,10-dihydroindeno[1,2-b]indol-10-yl group; an N-methyl-5,10-dihydroindeno[ 1,2-b]indol-10-yl group, and N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl group; 5,6-dihydroindeno[2,1-b]indol-6-yl group; N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl group, and N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl group; azapentalen-4-yl group; thiapentalen-4-yl group; azapentalen-6-yl group; thiapentalen-6-yl group; monomethylazapentalen-4-yl group, dimethylazapentalen-4-yl group, and trimethylazapentalen-4-yl group. A is preferably the above-mentioned Cp.

[0028] For example, in a metal-containing catalyst, the presence of a bulky group near the central metal increases the r Ｎ Furthermore, when Cp has a substituent on the cyclopentadiene ring or the condensed ring containing the cyclopentadiene ring, the value of r tends to be smaller than when Cp does not have a substituent on the cyclopentadiene ring or the condensed ring containing the cyclopentadiene ring. Ｎ Furthermore, when Cp has a substituent on the cyclopentadiene ring or a condensed ring containing a cyclopentadiene ring, the value of r tends to be small when the number of substituents is large. Ｎ The value tends to be small.

[0029] It has a structure corresponding to the structure of formula (C) above, and r Ｎ The value of is 1.0 × 10 －４Specific examples of the metal-containing catalyst include C1 and C2 below. On the other hand, there are catalysts having a structure corresponding to the structure of the above formula (C), but Ｎ The value of is 1.0 × 10 －４ Specific examples of the metal-containing catalyst having a r > 1 include the following C'1 and C'2. Note that the following C2 and the following C'1 have similar structures. However, the r Ｎ The values ​​of α and β are significantly different. This is thought to be due to the electron-rich Zr in C2, which is due to the electron-donating isopropyl group (iPr) attached to the cyclopentadiene ring. In C2, which has electron-rich Zr, norbornene is weakly coordinated, and it is presumed that the insertion reaction following coordination is unlikely to occur.

[0030] (C1:r Ｎ = 2.8 x 10 －７ ) (C2:r Ｎ = 6.4 x 10 －５ )

[0031] (C'1:r Ｎ = 3.3 x 10 －４ ) (C'2:r Ｎ = 3.3 x 10 －２ )

[0032] <Monomer> In the method for producing the cyclic olefin copolymer, a monomer containing a norbornene monomer and an olefin selected from ethylene and an α-olefin is used.

[0033] [Norbornene Monomer] The norbornene monomer will be described below.

[0034] Examples of the norbornene monomer include norbornene and substituted norbornene, and norbornene is preferred. The norbornene monomers may be used singly or in combination of two or more.

[0035] 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):

[0036] (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 and may form a ring together. n represents 0 or a positive integer, and when n is 2 or more, R ５ ~R ８ may be the same or different in each repeating unit. However, when n=0, R １ ~R ４ and R ９ ~R １２ At least one of the is not a hydrogen atom.

[0037] The substituted norbornene represented by general formula (I) will be explained. 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.

[0038] 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, and these may be different from each other, may be partially different, or may be the same as one another.

[0039] Also, R ９ ~R １２Specific examples of 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; a benzyl group, a phenethyl group, or another aralkyl group in which an aryl group is substituted on an alkyl group; and the like. These may be different from each other, may be partially different, or may be the same as each other.

[0040] 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.

[0041] 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.

[0042] 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[4.3.0.1２，５ ]deca-3,7-diene (trivial 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 a partially hydrogenated product thereof (or an adduct 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 ]dodec-3-ene, a tetracyclic olefin; 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 called 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.

[0043] Among these, alkyl-substituted norbornenes (for example, bicyclo[2.2.1]hept-2-ene substituted with one or more alkyl groups) and alkylidene-substituted norbornenes (for example, 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.

[0044] [Olefin] The olefin is selected from ethylene and α-olefins. Ethylene and α-olefins will be described below. As the α-olefin, any known α-olefin can be used without any particular limitation. The α-olefin may be substituted with at least one substituent such as a halogen atom.

[0045] The α-olefin is preferably a C3 to C12 α-olefin. The C3 to C12 α-olefin is not particularly limited, but examples 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.

[0046] As the cyclic olefin copolymers obtainable by polymerizing the monomers described above, norbornene monomer / ethylene copolymers, norbornene monomer / α-olefin copolymers, and norbornene monomer / ethylene / α-olefin copolymers are preferred, and norbornene monomer / ethylene copolymers and norbornene monomer / α-olefin copolymers are more preferred. As the norbornene monomer / ethylene / α-olefin copolymers, copolymers of a diene-type norbornene monomer such as 5-ethylidene-2-norbornene, ethylene, and propylene are preferred. 5-ethylidene-2-norbornene / ethylene / propylene copolymers are known as EPDM.

[0047] The polymerization reaction is carried out without using a solvent or with a small amount of solvent. Specifically, the polymerization is carried out under the condition that the ratio of the mass of the norbornene monomer to the mass of the polymerization solution in the polymerization vessel at the start of the polymerization is 80% by mass or more. The ratio of the mass of the norbornene monomer to the mass of the polymerization solution in the polymerization vessel at the start of the polymerization may be 85% by mass or more, or may be 90% by mass or more.

[0048] The polymerization pressure is preferably 1 to 25 atmospheres as a gauge pressure when the metal-containing catalyst is added to the polymerization vessel. In particular, when the olefin is in a gaseous state under the charging conditions, the charging pressure of the olefin into the polymerization vessel is preferably 1 to 25 atmospheres as a pressure when the catalyst is added to the polymerization vessel. The charging pressure is a gauge pressure.

[0049] The temperature at which the monomers in the polymerization vessel are polymerized is preferably 50 to 150°C, more preferably 50 to 130°C. The polymerization time is not particularly limited, and polymerization is carried out until a desired yield is achieved or until the molecular weight of the cyclic olefin copolymer has increased to a desired level. The polymerization time varies depending on the polymerization 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.

[0050] Generally, when ethylene charged at high pressure and norbornene monomer are copolymerized at high temperatures, such as 50°C or higher, in the presence of a highly active catalyst, polymerization of ethylene with itself tends to proceed, resulting in the production of polyethylene-like impurities. If a cyclic olefin copolymer contains polyethylene-like impurities, the cyclic olefin copolymer becomes turbid when dissolved in a solvent. Therefore, whether a cyclic olefin copolymer contains polyethylene-like impurities can be confirmed by visually observing a solution in which the cyclic olefin copolymer is dissolved in toluene at a concentration of 1% by mass. If the solution becomes turbid, it can be said that the cyclic olefin copolymer contains polyethylene-like impurities. As can be understood from this phenomenon, the presence of polyethylene-like impurities in a cyclic olefin copolymer raises concerns about a decrease in the transparency of the cyclic olefin copolymer. Therefore, if polyethylene-like impurities are generated during the production of a cyclic olefin copolymer, a process is required to filter and remove the unnecessary polyethylene-like impurities, which increases production costs. However, when ethylene is used as the olefin, the production of polyethylene-like impurities can be suppressed by copolymerizing norbornene monomer and ethylene using the above method.

[0051] The presence of polyethylene-like impurities can also be confirmed by measuring the cyclic olefin copolymer using a differential scanning calorimeter (DSC). Specifically, the cyclic olefin copolymer is measured by DSC in a nitrogen atmosphere at a heating rate of 20°C / min according to the method described in JIS K7121 to obtain a DSC curve. Next, the presence or absence of a melting point (melting enthalpy) peak attributable to the polyethylene-like impurities is confirmed in the obtained DSC curve. When the cyclic olefin copolymer contains polyethylene-like impurities, the melting point peak attributable to the polyethylene-like impurities on the DSC curve is generally detected within the range of 100°C to 140°C.

[0052] A solvent may be charged into the polymerization vessel together with the norbornene monomer and the olefin, as long as the desired effect is not impaired. The solvent is not particularly limited as long as it does not inhibit the polymerization reaction. Examples of the solvent include hydrocarbon solvents such as pentane, hexane, heptane, octane, cyclohexane, mineral oil, benzene, toluene, and xylene, and halogenated hydrocarbon solvents such as chloroform, methylene chloride, dichloroethane, and chlorobenzene.

[0053] The polymerization of the monomers is preferably carried out in the presence of one or more cocatalysts selected from aluminoxanes, alkyl metal compounds, borate compounds, and organic phosphine compounds.

[0054] [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. When producing the catalyst composition, one aluminoxane may be used alone, or two or more aluminoxanes may be used in combination.

[0055] 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.

[0056] (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.)

[0057] 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.

[0058] 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, and TMAO-340 series (all manufactured by Tosoh Finechem Corporation), and methylaluminoxane solution (manufactured by Albemarle Corporation).

[0059] The amount of aluminoxane used together with the metal-containing catalyst is preferably 10 to 100,000 moles, more preferably 100 to 10,000 moles, in terms of the number of moles of aluminum atoms per mole of the metal-containing catalyst.

[0060] [Alkyl Metal Compound] As the alkyl metal compound, various alkyl metal compounds conventionally used as cocatalysts in the polymerization of various olefins can be used without particular limitation. As the alkyl metal compound, it is preferable to use at least one of an alkyl aluminum compound having at least one alkyl group bonded to an Al atom and an alkyl zinc compound having at least one alkyl group bonded to a Zn atom. One type of alkyl metal compound may be used alone, or two or more types may be used in combination.

[0061] As the alkylaluminum compound, any compound conventionally used for the polymerization of olefins or the like can be used without any particular limitation. Examples of the alkylaluminum compound include compounds represented by the following general formula (II): (R １１ ) ｚ１ AlX ３－ｚ１ (II) (In formula (II), R １１ 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.

[0062] R １１ 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, 1 to 8 is more preferable, and 2 to 8 is even more preferable. 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.

[0063] Specific examples of the alkylaluminum compound 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-propylaluminum hydride, diisopropylaluminum 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.

[0064] As the alkylzinc compound, any compound conventionally used for the polymerization of olefins can be used without any particular limitation. Examples of the alkylzinc compound include compounds represented by the following general formula (III): (R １２ ) ｚ２ ZnX ２－ｚ２ (III) (In formula (III), R １２ 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.

[0065] R １２The 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, 1 to 8 is more preferable, and 2 to 8 is even more preferable. 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.

[0066] Specific examples of the alkyl zinc compound include dialkyl zincs such as dimethyl zinc, diethyl zinc, di-n-propyl zinc, diisopropyl zinc, di-n-butyl zinc, diisobutyl zinc, di-sec-butyl zinc, di-n-pentyl zinc, di-n-hexyl zinc, di-n-heptyl zinc, and di-n-octyl zinc; alkyl zinc halides such as methyl zinc chloride, ethyl zinc chloride, and isobutyl zinc chloride; and alkyl zinc hydrides such as methyl zinc hydride, ethyl zinc hydride, and isobutyl zinc hydride.

[0067] 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.

[0068] The amount of alkyl metal compound used together with the metal-containing catalyst is preferably 10 to 100,000 moles, more preferably 100 to 10,000 moles, in terms of the number of moles of metal contained in the alkyl metal compound per mole of the metal-containing catalyst.

[0069] [Borate Compound] As the borate compound, various borate compounds that have conventionally been used as co-catalysts or the like in the polymerization of various olefins can be used without particular limitation. Specific preferred examples of the borate compound include tetrakis(pentafluorophenyl)trityl borate, dimethylphenylammonium tetrakis(pentafluorophenyl)borate, and N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate. The amount of the borate compound used together with the metal-containing catalyst is preferably 1 to 3 mol, more preferably 1 to 2 mol, per 1 mol of the metal-containing catalyst.

[0070] The polymerization of the monomers is also preferably carried out in the presence of a chain transfer agent. Examples of chain transfer agents include alcohols, thiols, ketones, aldehydes, amines, and hydrogen. Among these, amines and hydrogen are preferred as chain transfer agents.

[0071] Specific examples of chain transfer agents include alcohols such as methanol, ethanol, propanol, isopropanol, butanol, and pentanol; thiols such as ethanethiol, n-propanethiol, 2-propanethiol, n-butanethiol, 1,1-dimethylethanethiol, 2-butanethiol, 2-methyl-2-propanethiol, n-pentanethiol, 2-pentanethiol, 3-pentanethiol, 2-methyl-2-butanethiol, 3-methyl-2-butanethiol, and n-hexanethiol; ketones such as acetone, methyl ethyl ketone, diethyl ketone, and diamyl ketone; aldehydes such as acetaldehyde, propionaldehyde, butanal, and pentanal; ethylamine, diethylamine, triethylamine, propylamine, tripropylamine, dipropylamine, butylamine, dibutylamine, and tributylamine; and hydrogen.

[0072] The amount of the chain transfer agent used is preferably 1 to 100,000 mol, and more preferably 10 to 10,000 mol, per mol of the metal-containing catalyst. When the chain transfer agent is hydrogen, the amount of hydrogen used is preferably 0.0001 to 1 atmosphere, and more preferably 0.001 to 0.1 atmosphere, in terms of the partial pressure of hydrogen in the polymerization vessel at the time of adding the catalyst.

[0073] <Cyclic Olefin Copolymer> The cyclic olefin copolymer obtained by the above production method contains a structural unit derived from a norbornene monomer and a structural unit derived from an olefin selected from ethylene and an α-olefin. Hereinafter, the cyclic olefin copolymer obtained by the above production method will be simply referred to as a "cyclic olefin copolymer." A structural unit derived from a norbornene monomer will be referred to as "N" and will also be referred to as a "structural unit N derived from a norbornene monomer" or "structural unit N." A structural unit derived from an olefin will be referred to as "O" and will also be referred to as an "olefin-derived structural unit O" or "structural unit O." The cyclic olefin copolymer may or may not contain a diadjoint moiety in which two structural units N derived from a norbornene monomer are bonded. The diadjoint moiety is a meso-type diadjoint moiety and / or a racemo-type diadjoint moiety. The cyclic olefin copolymer may or may not contain a triad moiety in which three structural units N derived from a norbornene monomer are bonded. The ratio of the number of moles of the structural unit N constituting the diad moiety to the number of moles of all structural units of the cyclic olefin copolymer is preferably 10 mol% or less. When the cyclic olefin copolymer contains a diad moiety, the ratio Mm / Mr of the number of moles of the racemo-type diad moiety Mr to the number of moles of the meso-type diad moiety Mm is preferably 0.01 to 30. The ratio of the number of moles of the structural unit N constituting the triad to the number of moles of all structural units of the cyclic olefin copolymer is preferably 1.0 mol% or less.

[0074] When the norbornene monomer is norbornene, the meso-type dyad structure is represented by the following formula (A), and the racemo-type dyad structure is represented by the following formula (B).

[0075] The cyclic olefin copolymer contains little or no diad moieties in which two structural units N derived from norbornene monomers are bonded. The cyclic olefin copolymer contains little or no triad moieties in which three structural units N derived from norbornene monomers are bonded. In other words, in the molecular chain of the cyclic olefin copolymer, there are few moieties in which structural units N derived from norbornene monomers are present consecutively, or there are no consecutive structural units N. For this reason, the cyclic olefin copolymer has few or no norbornene monomer blocks in which structural units N are present consecutively, and therefore has a smaller free volume than conventional cyclic olefin copolymers containing a large amount of norbornene monomer blocks. As a result, the cyclic olefin copolymer exhibits excellent water vapor barrier properties.

[0076] Furthermore, norbornene monomer blocks having successive structural units N adversely affect the impact resistance of the cyclic olefin copolymer, and therefore, when the cyclic olefin copolymer contains little or no norbornene monomer blocks having successive structural units N, the cyclic olefin copolymer exhibits excellent impact resistance.

[0077] Furthermore, the cyclic olefin copolymer is less likely to discolor or crack when exposed to high temperatures for a long period of time.

[0078] The ratio of the number of moles of the structural unit N constituting the diadult moiety to the number of moles of all structural units of the cyclic olefin copolymer is preferably 10 mol% or less, more preferably 7 mol% or less, even more preferably 5 mol% or less, and particularly preferably 3 mol% or less. The lower limit of the ratio of the number of moles of the structural unit N constituting the diadult moiety to the number of moles of all structural units of the cyclic olefin copolymer is not particularly limited as long as the desired effect is not impaired. The lower limit of the ratio of the number of moles of the structural unit N constituting the diadult moiety to the number of moles of all structural units of the cyclic olefin copolymer may be, for example, 0 mol% or more, 0.1 mol% or more, 0.3 mol% or more, or 0.5 mol% or more. Therefore, for example, the ratio of the number of moles of the structural units N constituting the diad moiety to the number of moles of all structural units of the cyclic olefin copolymer may be 0 to 10 mol%, 0.1 to 10 mol%, 0.3 to 10 mol%, 0.5 to 10 mol%, 0 to 7 mol%, 0.1 to 7 mol%, 0.3 to 7 mol%, 0.5 to 7 mol%, 0 to 5 mol%, 0.1 to 5 mol%, 0.3 to 5 mol%, 0.5 to 5 mol%, 0 to 3 mol%, 0.1 to 3 mol%, 0.3 to 3 mol%, or 0.5 to 3 mol%.

[0079] The ratio of the number of moles of the structural unit N constituting the triad moiety to the number of moles of all structural units of the cyclic olefin copolymer is preferably 1.0 mol% or less, more preferably 0.5 mol% or less, even more preferably 0.3 mol% or less, particularly preferably 0.1 mol% or less, and most preferably 0 mol%. The lower limit of the ratio of the number of moles of the structural unit N constituting the triad moiety to the number of moles of all structural units of the cyclic olefin copolymer is not particularly limited as long as the desired effect is not impaired. The lower limit of the ratio of the number of moles of the structural unit N constituting the triad moiety to the number of moles of all structural units of the cyclic olefin copolymer may be, for example, 0 mol% or more, 0.01 mol% or more, 0.03 mol% or more, or 0.05 mol% or more. Therefore, the ratio of the number of moles of the structural units N constituting the triad moiety to the number of moles of all structural units of the cyclic olefin copolymer may be 0 to 1.0 mol%, 0.01 to 1.0 mol%, 0.03 to 1.0 mol%, 0.05 to 1.0 mol%, 0 to 0.5 mol%, 0.01 to 0.5 mol%, 0.03 to 0.5 mol%, 0.05 to 0.5 mol%, 0 to 0.3 mol%, 0.01 to 0.3 mol%, 0.03 to 0.3 mol%, 0.05 to 0.3 mol%, 0 to 0.1 mol%, 0.01 to 0.1 mol%, 0.03 to 0.1 mol%, or 0.05 to 0.1 mol%.

[0080] In the cyclic olefin copolymer, the ratio Mm / Mr of the number of moles Mr of racemo-type diadjoint moieties to the number of moles Mm of meso-type diadjoint moieties is preferably 0.01 to 30, more preferably 0.1 to 27, and even more preferably 0.5 to 25. When the ratio Mm / Mr is 0.01 to 30, the cyclic olefin copolymer has excellent water vapor barrier properties.

[0081] The cyclic olefin copolymer may contain other structural units in addition to the structural unit N derived from a norbornene monomer and the structural unit O derived from an olefin selected from ethylene and an α-olefin. The monomer that provides the other structural units is not particularly limited as long as it is a monomer that is copolymerizable with a norbornene monomer, ethylene, and an α-olefin. The content of the other structural units in the cyclic olefin copolymer is not particularly limited as long as the desired effects are not impaired, but is preferably 10 mol % or less, more preferably 5 mol % or less, even more preferably 3 mol % or less, particularly preferably 1 mol % or less, and most preferably 0 mol %, based on the number of moles of all structural units of the cyclic olefin copolymer.

[0082] The content of the structural unit N derived from a norbornene monomer in the cyclic olefin copolymer is not particularly limited as long as the desired effect is not impaired. The content of the structural unit N is preferably 50 mol% or less, more preferably 20 to 50 mol%, even more preferably 25 to 50 mol%, and particularly preferably 30 to 50 mol%, based on the number of moles of all structural units in the cyclic olefin copolymer. If the content of the structural unit N is 50 mol% or less based on the number of moles of all structural units in the cyclic olefin copolymer, the cyclic olefin copolymer tends to exhibit a low glass transition temperature, which is preferable.

[0083] The content of the structural unit O derived from an olefin selected from ethylene and an α-olefin in the cyclic olefin copolymer is not particularly limited as long as the desired effect is not impaired. The content of the structural unit O is preferably 50 mol % or more, more preferably 50 to 80 mol %, even more preferably 50 to 75 mol %, and particularly preferably 50 to 70 mol %, based on the number of moles of all structural units in the cyclic olefin copolymer.

[0084] The cyclic olefin copolymer produced by the above method has a low glass transition temperature and is therefore excellent in processability. Furthermore, the cyclic olefin copolymer produced by the above method has excellent water vapor barrier properties and transparency. Therefore, the cyclic olefin copolymer produced by the above method is particularly preferably used as a material for optical films or optical sheets, packaging films or sheets, and the like, which require high water vapor barrier properties and high transparency.

[0085] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0086] [Examples 1 to 9, Comparative Examples 1 and 2] In producing cyclic olefin copolymers, the following metal-containing catalysts C1 and C2 were used in the examples, and the following metal-containing catalysts C'1 and C'2 were used in the comparative examples.

[0087] (C1:r Ｎ = 2.8 x 10 －７ ) (C2:r Ｎ = 6.4 x 10 －５ )

[0088] (C'1:r Ｎ = 3.3 x 10 －４ ) (C'2:r Ｎ = 3.3 x 10 －２ )

[0089] In the examples and comparative examples, the following co-catalysts CC1 to CC4 were used: CC1: N-methyldialkylammonium tetrakis(pentafluorophenyl)borate (alkyl: C14 to C18 (average: C17.5) (manufactured by Tosoh Finechem Co., Ltd.) CC2: Triisobutylaluminum (manufactured by Tosoh Finechem Co., Ltd.) CC3: TMAO-211 toluene solution (methylaluminoxane solution, manufactured by Tosoh Finechem Co., Ltd.) CC4: 40.6 mass% (as Al atom content) solid MAO toluene solution (average particle size d(0.5) 5.6 μm (measurement dispersion medium: toluene), slurry concentration 12.2 wt%, manufactured by Tosoh Finechem Co., Ltd.)

[0090] All operations were carried out under an inert gas atmosphere. Two thoroughly dried 20 mL Schlenk flasks were prepared. To one Schlenk flask, a metal-containing catalyst and triisobutylaluminum listed in Table 1 were added in a mass ratio of 1:1000. To the other Schlenk flask, a cocatalyst listed in Table 1 was added. Toluene was added to each Schlenk flask to obtain a metal-containing catalyst solution and a cocatalyst solution. A thoroughly dried 150 mL stainless steel autoclave containing a stirrer was heated to the polymerization temperature listed in Table 1 (60-90°C), and 20 mL of norbornene melt at 80°C was added using a pre-heated syringe. The norbornene in the autoclave was stirred for 5 minutes, and then a metal-containing catalyst solution containing 0.1 μmol of the metal-containing catalyst was added to the autoclave. The cocatalyst solution prepared by the above method was then added to the autoclave so that the molar ratio of the cocatalyst to the metal-containing catalyst was the molar ratio listed in Table 1. Next, polymerization was initiated by applying ethylene pressure to the autoclave to a gauge pressure of 0.9 MPa. The polymerization initiation point was 30 seconds after applying pressure. The total volume of the monomer solution immediately before applying ethylene pressure was 21 mL. 15 minutes after the start of polymerization, the ethylene supply was stopped, and the pressure was carefully returned to normal pressure. The polymerization solution was then immediately poured into a mixed solvent consisting of 50 mL of acetone, 50 mL of methanol, and 1.5 mL of hydrochloric acid to precipitate the resulting cyclic olefin copolymer. The resulting precipitate was collected by suction filtration. The collected precipitate was washed with acetone and methanol, and then vacuum-dried at 110°C for 12 hours to obtain a norbornene-ethylene copolymer as the cyclic olefin copolymer. The copolymer yield (g) per 1 μg of catalyst, calculated from the amount of catalyst used and the amount of cyclic olefin copolymer obtained, is shown in Table 1. In Example 4, 200 moles of triethylamine were used as a chain transfer agent per mole of the metal-containing catalyst. In Example 5, 500 moles of triethylamine was used as a chain transfer agent relative to 1 mole of the metal-containing catalyst. In Examples 7 and 9, hydrogen gas equivalent to a partial pressure of 0.01 atmospheres was added to the polymerization vessel as a chain transfer agent.

[0091] The obtained cyclic olefin copolymers of each Example and Comparative Example were subjected to the following methods: measurement of glass transition temperature, molecular weight measurement by gel permeation chromatography, thermal analysis of impurities, and turbidity test. The measurement results and test results are shown in Table 1.

[0092] <Glass Transition Temperature (Tg)> The Tg of the cyclic olefin copolymer was measured by a DSC method (the method described in JIS K7121). DSC device: differential scanning calorimeter (DSC-Q1000 manufactured by TA Instruments) Measurement atmosphere: nitrogen Heating condition: 20°C / min

[0093] <Thermal analysis of impurities> In the DSC curve obtained by measuring the glass transition temperature, the calorific value (mJ / mg) was calculated from the area of ​​the peak at the melting point derived from polyethylene-like impurities observed within the range of 100°C to 140°C. The larger the calculated calorific value, the higher the content of polyethylene-like impurities. Note that ND in Table 1 indicates that no peak derived from polyethylene-like impurities was detected on the DSC curve.

[0094] <Turbidity test> 0.5 g of the obtained cyclic olefin copolymer was dissolved in 45 g of toluene, and the presence or absence of turbidity in the solution was observed. When turbidity was observed, it was judged as ×, and when no turbidity was observed, it was judged as ○.

[0095] *Cyclic olefin copolymer yield (g) per 1 μg of catalyst

[0096] It can be seen from Table 1 that the cyclic olefin copolymers of the examples produced by the above-mentioned predetermined methods have low glass transition temperatures (Tg) and excellent processability.

[0097] Furthermore, for the cyclic olefin copolymers obtained in Example 1, Example 6, Comparative Example 1, and Comparative Example 2, the ratio of the structural unit N derived from norbornene monomer, the ratio of the structural unit N constituting a diad moiety formed by bonding two structural units N, and the ratio of the structural unit N constituting a triad moiety formed by bonding three structural units N, and the meso / racemo ratio for the diad moiety were measured according to the following methods: １３It was calculated from the integral value of the spectrum observed by C-NMR.

[0098] The primary structures of the polymers identified by the respective spectra are described in "Macromol. Chem. Phs. 1999, Vol. 200, Page 1340", "Macromolecules 2004, Vol. 37, Page 9681", "Macromolecules 2000, Vol. 33, Page 8931", etc.

[0099] A specific method for calculating parameters when the norbornene monomer is norbornene and the olefin is ethylene will be described below.

[0100] First, the calculation of the composition will be described. １３ The integral value observed at chemical shift values ​​of 44.5-56.0 ppm in the spectrum chart obtained by C-NMR: I Ｃ２，Ｃ３ (originating from the 2nd and 3rd positions of the norbornene ring), integral value observed at chemical shift values ​​of 37.0-44.0 ppm: I Ｃ１，Ｃ４ (derived from the carbon atoms at the 1st and 4th positions of the norbornene ring), the integral value observed at the chemical shift value of 36.5-33.0 ppm: I Ｃ７ (derived from the carbon at position 7 of the norbornene ring), integral observed at chemical shift values ​​of 44.5-56.0 ppm: I Ｃ５，Ｃ６ +I Ｅ (derived from the carbon atoms at the 5th and 6th positions of the norbornene ring and the carbon atom of the ethylene moiety), the composition of the structural unit N (mol %) is calculated by the following formula: Ｃ２，Ｃ３ +I Ｃ１，Ｃ４ +2×I Ｃ７ ) ÷ (I Ｃ５，Ｃ６ +I Ｅ ) × 100. In addition, the proportion of the structural unit O derived from the olefin can be calculated by subtracting the composition of the structural unit N from 100%.

[0101] The ratio of the amount of diad moiety (NN dyad) and triad moiety (NN triad) can be calculated by determining the distribution of the six triads (EEE, EEN, NEN, NNN, NNE, ENE) described in "Maclomol. Chem. Phs. 1999, Vol. 200, Page 1340" and using the following formula. N represents a structural unit derived from a norbornene monomer, and E represents a structural unit derived from ethylene. The ratio of the amount of diad moiety (NN dyad) is the ratio of the number of structural units N derived from a norbornene monomer constituting the diad moiety to the total structural units of the cyclic olefin copolymer. The ratio of the amount of triad moiety (NN triad) is the ratio of the number of structural units N derived from a norbornene monomer constituting the triad moiety to the total structural units of the cyclic olefin copolymer. NN dyad (mol%) = (2 x NNN + ENN) ÷ (2 x ENN + 2 x ENE + 2 x NNN) x 100 NN triad (mol%) = NNN ÷ (ENN + ENE + NNN) x 100

[0102] The mole fraction of the meso form of the NN dyad is calculated from the average value of the integral of the C5 ENNE-meso peak (28.0-28.5 ppm) and the C6 ENNE-meso peak (31.5-31.8 ppm) divided by the peak of the C5, C6, and ethylene moieties (29.4-32.5 ppm), and the integral of the C7 ENNE-meso peak (33.1-33.2 ppm) divided by the composition of the structural unit N derived from norbornene monomer and the integral of the C7 region (32.6-39 ppm).

[0103] Similarly, the mole fraction of the racemoisomer of the NN dyad is calculated from the average of the integral of the C5 ENNE-racemoisomer peak (28.0-28.5 ppm) and the C6 ENNE-racemoisomer peak (31.2-31.4 ppm) divided by the peak of the C5, C6, and ethylene moieties (28-32.5 ppm), and the integral of the C7 ENNE-racemoisomer peak (33.4-33.8 ppm) divided by the norbornene composition and the integral of the C7 region (32.6-39 ppm).

[0104] An example of sample preparation conditions and measurement conditions is as follows: Solvent: 1,1,2,2-tetrachloroethane-d2 (containing 10% by volume of hexamethyldisilane) Concentration: 70 mg / mL Apparatus: Bruker AVANCE600 (resonance frequency of hydrogen atoms: 600 MHz) Sample tube diameter: 10 mm Measurement method: power gate type Pulse width: 15 μsec Delay time: 2.089 sec Data acquisition time: 0.911 sec Observation frequency width: 35971.22 Hz Decoupling: complete decoupling Number of accumulations: 18,000 Chemical shift reference: the hexamethyldisilane peak is set to −2.43 ppm.

[0105] The ratio of the structural units N derived from norbornene monomers to all structural units of the cyclic olefin copolymer, the ratio Mr of the structural units N constituting the racemo-type diadult moiety, the ratio Mm of the structural units N constituting the meso-type diadult moiety, and Mm / Mr, all determined by the above measurements, are shown in Table 2.

[0106] Furthermore, the cyclic olefin copolymers obtained in Example 1, Example 6, Comparative Example 1, and Comparative Example 2 were subjected to an impact resistance test and a water vapor barrier property test according to the following methods.

[0107] <Impact Resistance Test> The obtained cyclic olefin copolymer was melted. The molten cyclic olefin copolymer was formed into a film on a glass substrate and then cooled to prepare a film sample with a thickness of 50 μm. Using a specimen cut out from the obtained film sample, impact resistance was evaluated using a film impact tester in accordance with ASTM-D3420. The results are shown in Table 2. When the measured value of impact resistance was 0.35 J or less, it was rated as ×, and when the measured value of impact resistance was more than 0.35 J, it was rated as ○.

[0108] <Water Vapor Barrier Property Test> The obtained cyclic olefin copolymer was melted. The molten cyclic olefin copolymer was formed into a film on a glass substrate and then cooled to prepare a film sample with a thickness of 100 μm. The water vapor barrier property of the obtained film sample was evaluated under conditions of 40° C. and 90% RH according to the method of JIS Z0208. The water vapor barrier property was measured in g / m ２The water vapor barrier property was evaluated in units of 4 g / m / 24 h. ２ / 24h or less was evaluated as "Good" and the measured value of water vapor barrier property was 4g / m ２ The results are shown in Table 2.

[0109]

[0110]

[0046] Table 2 shows that the cyclic olefin copolymers obtained in Examples 1 and 6, which were produced by the above-described method and had small amounts of diads formed from the structural unit N derived from a norbornene monomer and small amounts of triads formed from the structural unit N derived from a norbornene monomer, not only had excellent water vapor barrier properties but also excellent impact resistance. On the other hand, the cyclic olefin copolymers obtained in Comparative Examples 1 and 2, which had large amounts of diads formed from the structural unit N derived from a norbornene monomer and large amounts of triads formed from the structural unit N derived from a norbornene monomer, were poor in water vapor barrier properties and impact resistance.

[0111] Furthermore, Tables 1 and 2 show that the cyclic olefin copolymers obtained in Examples 1 and 6, in which the amount of diads formed from the structural unit N derived from a norbornene monomer and the amount of triads formed from the structural unit N derived from a norbornene monomer are small, have a low glass transition temperature (Tg) and excellent processability.

Claims

1. A method for producing a cyclic olefin copolymer containing a constituent unit derived from a norbornene monomer and a constituent unit derived from an olefin selected from ethylene and an α-olefin, comprising: charging at least the norbornene monomer and the olefin as monomers into a polymerization vessel; and polymerizing the monomer in the polymerization vessel in a molten state of the norbornene monomer in the presence of a metal-containing catalyst having a structure in which one or more ligands are coordinated to a central metal; wherein the ratio of the mass of the norbornene monomer to the mass of the polymerization solution in the polymerization vessel at the start of polymerization is 80 mass% or more; and the monomer reactivity ratio r of the metal-containing catalyst at 1 atmospheric pressure and a reaction temperature of 363.15 K is 0.05 to 0.5 mass%. Ｎ The value is 1.0 x 10 －４ is equal to or less than r Ｎ The value of k is the insertion rate constant of norbornene into norbornene bound to the metal-containing catalyst. ＮＮ and the insertion rate constant k of ethylene into norbornene bound to the metal-containing catalyst. ＮＥ Relative to k ＮＮ / k ＮＥ The value of r Ｎ is represented by the following formula (r1): Ｎ =exp(-(G ‡ ＮＮ -G ‡ ＮＥ ) / RT) ... (r1) (In formula (r1), G ‡ ＮＮ is the Gibbs free energy of activation of the insertion reaction of norbornene into norbornene bound to the metal catalyst, and G ‡ ＮＥ is the Gibbs free energy of activation of the insertion reaction of ethylene into the norbornene bound to the metal catalyst, R is the gas constant, and T is the reaction temperature of 363.15 K. ‡ ＮＮ , and the G ‡ ＮＥ is calculated by a density functional method based on the DFT theory M06-2X and the basis set cc-pVDZ-(PP), and the metal-containing catalyst contains Ti, Zr, Hf, Ni, Pd, or Pt as the central metal.

2. The method for producing a cyclic olefin copolymer according to claim 1, wherein the polymerization solution in the polymerization vessel at the start of polymerization does not contain an organic solvent.

3. The method for producing a cyclic olefin copolymer according to claim 1 or 2, wherein the polymerization pressure is 1 to 25 atm as a gauge pressure when the metal-containing catalyst is added into the polymerization vessel.

4. The method for producing a cyclic olefin copolymer according to claim 1 or 2, wherein the polymerization of the monomers is carried out at 50 to 150°C.

5. The method for producing a cyclic olefin copolymer according to claim 1 or 2, wherein the polymerization of the monomers is carried out in the presence of one or more cocatalysts selected from aluminoxanes, alkyl metal compounds, borate compounds, and organic phosphine compounds.

6. The method for producing a cyclic olefin copolymer according to claim 1 or 2, wherein the polymerization of the monomers is carried out in the presence of a chain transfer agent.

7. The method for producing a cyclic olefin copolymer according to claim 6, wherein the chain transfer agent is hydrogen or an amine.

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