Cyclic olefin copolymer production method

Abstract

Provided is a cyclic olefin copolymer production method that can produce, with high efficiency, a cyclic olefin copolymer that is a copolymer of a cyclic olefin monomer and an α-olefin monomer having 3-20 carbon atoms and that has excellent toughness.　According to the present invention, a copolymer of a cyclic olefin monomer and an α-olefin monomer having 3-20 carbon atoms is produced using a method comprising: a first polymerization for polymerizing monomers including the cyclic olefin monomer and the α-olefin monomer in a polymerization vessel in the presence of a titanocene catalyst, an alkyl aluminum compound, and a borate compound; addition of an alkyl aluminum compound solely to the polymerization vessel after the first polymerization; and a second polymerization for further adding the monomers into the polymerization vessel after the addition of the alkyl aluminum compound, and continuously polymerizing the monomers.

Description

Method for producing cyclic olefin copolymer

[0001] The present invention relates to a method for producing a cyclic olefin copolymer.

[0002] Cyclic olefin polymers and cyclic olefin copolymers (also referred to as "COP" and "COC," respectively) have low moisture absorption and high transparency. For this reason, COPs and COCs are used in a variety of applications, including optical materials such as optical disk substrates, optical films, and optical fibers. A typical COC is a copolymer of a cyclic olefin and ethylene. The glass transition temperature (Tg) of such a copolymer can be changed by the copolymerization composition of the cyclic olefin and ethylene. Therefore, a copolymer of a cyclic olefin and ethylene can be produced as a copolymer with a higher Tg than COPs, and it is even possible to achieve a Tg of over 200°C, which is difficult to achieve with COPs. However, such copolymers are hard and brittle. Therefore, such copolymers have problems such as low mechanical strength and poor handleability and processability.

[0003] One method for improving the mechanical strength of high TgCOC is to copolymerize a cyclic olefin with an α-olefin other than ethylene (hereinafter referred to as a "specific α-olefin"). Various studies have been conducted on the copolymerization of a cyclic olefin with a specific α-olefin.

[0004] Copolymerization of a cyclic olefin with a specific α-olefin is significantly different from copolymerization of a cyclic olefin with ethylene. Under conditions under which a high molecular weight product can be obtained by copolymerization of a cyclic olefin with ethylene, a chain transfer reaction caused by the specific α-olefin occurs in the copolymerization of a cyclic olefin with a specific α-olefin, making it difficult to obtain a high molecular weight product. Therefore, copolymers of a cyclic olefin with a specific α-olefin have been considered unsuitable for use as molding materials (see, for example, Non-Patent Document 1).

[0005] For this reason, various studies have been conducted to improve the moldability of copolymers of cyclic olefins and specific α-olefins. For example, as a method for producing a copolymer of cyclic olefins and specific α-olefins that has a relatively high molecular weight and can be molded into a film, a method has been proposed in which a cyclic olefin and a specific α-olefin are copolymerized in the presence of a titanocene catalyst having a specific structure and triphenylmethylium tetrakis(pentafluorophenyl)borate (see Patent Document 1).

[0006] JP 2016-56275 A

[0007] Jung, H. Y. et al., Polyhedron, 2005, Vol. 24, pp. 1269-1273

[0008] However, even with the method described in Patent Document 1, it is difficult to efficiently produce a copolymer of a cyclic olefin and a specific α-olefin as a cyclic olefin copolymer having excellent toughness.

[0009] The present invention has been made in view of the above circumstances, 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 which is a copolymer of a cyclic olefin monomer and an α-olefin monomer having 3 to 20 carbon atoms and has excellent toughness.

[0010] The present inventors have found that the above-mentioned problems can be solved by producing a copolymer of a cyclic olefin monomer and an α-olefin monomer having 3 to 20 carbon atoms by a method comprising: a first polymerization step in which monomers including the cyclic olefin monomer and the α-olefin monomer are polymerized in a polymerization vessel in the presence of a titanocene catalyst, an alkylaluminum compound, and a borate compound; adding the alkylaluminum compound alone to the polymerization vessel after the first polymerization step; and a second polymerization step in which, after the addition of the alkylaluminum compound, additional monomers are added to the polymerization vessel and the monomers are subsequently polymerized. Based on this discovery, the present invention provides the following.

[0011] (I) A method for producing a cyclic olefin copolymer having units derived from a cyclic olefin monomer and units derived from an α-olefin monomer having 3 to 20 carbon atoms, the method comprising: a first polymerization step of polymerizing monomers including the cyclic olefin monomer and the α-olefin monomer in a polymerization vessel in the presence of a titanocene catalyst, an alkylaluminum compound, and a borate compound; adding the alkylaluminum compound alone to the polymerization vessel after the first polymerization step; and a second polymerization step of adding monomers to the polymerization vessel after the addition of the alkylaluminum compound and subsequently polymerizing the monomers, wherein the polymerization of the monomers in the first polymerization step is carried out until the reaction rate of the cyclic olefin monomer becomes 80 mol % or more relative to the total number of moles of the cyclic olefin monomer added to the polymerization vessel at the start of the first polymerization and during the first polymerization step, and the reaction rate of the α-olefin monomer becomes 80 mol % or more relative to the total number of moles of the α-olefin monomer added to the polymerization vessel at the start of the first polymerization and during the first polymerization step.

[0012] (II) The method for producing a cyclic olefin copolymer according to (I), wherein the polymerization reaction is terminated after the second polymerization is carried out.

[0013] (III) The method for producing a cyclic olefin copolymer according to (I), wherein, after a first second polymerization, the addition of an alkylaluminum compound and the second polymerization are repeated until the number of times the alkylaluminum compound has been added reaches n, n being an integer of 2 or greater, and the pth addition of the alkylaluminum compound among the 2nd to nth additions is carried out after the (p-1)th second polymerization, the reaction rate of the cyclic olefin monomer has reached 80 mol % or more relative to the sum of the number of moles of the cyclic olefin monomer in the polymerization vessel at the start of the (p-1)th second polymerization and the number of moles of the cyclic olefin monomer added to the polymerization vessel during the (p-1)th second polymerization, and the reaction rate of the α-olefin monomer has reached 80 mol % or more relative to the sum of the number of moles of the α-olefin monomer in the polymerization vessel at the start of the (p-1)th second polymerization and the number of moles of the α-olefin monomer added to the polymerization vessel during the (p-1)th second polymerization, and p is an integer of 2 to n, and the polymerization reaction is terminated after the nth second polymerization.

[0014] (IV) The method for producing a cyclic olefin copolymer according to (II), wherein in the first polymerization and / or the second polymerization, the monomers are added to the polymerization vessel in two or more divided portions.

[0015] (V) The method for producing a cyclic olefin copolymer according to (IV), wherein in the first polymerization and / or the second polymerization, the monomers are added to the polymerization vessel in two separate batches.

[0016] (VI) The method for producing a cyclic olefin copolymer according to (V), wherein in the first polymerization and the second polymerization, the monomers are added to the polymerization vessel in two separate batches.

[0017] (VII) The method for producing a cyclic olefin copolymer according to (III), wherein in the first polymerization and / or at least one of the n second polymerizations, the monomer is divided into two or more portions and added to the polymerization vessel in portions.

[0018] (VIII) The method for producing a cyclic olefin copolymer according to (VII), wherein in the first polymerization and / or at least one of the n second polymerizations, the monomer is divided into two portions and added to the polymerization vessel in separate portions.

[0019] (IX) The method for producing a cyclic olefin copolymer according to (VIII), wherein in all of the first polymerization and the n second polymerizations, the monomers are added to the polymerization vessel in two separate batches.

[0020] (X) The method for producing a cyclic olefin copolymer according to any one of (I) to (IX), wherein the alkylaluminum compound used in the first polymerization is a long-chain alkylaluminum compound having only alkyl groups having 6 or more carbon atoms, and the alkylaluminum compound added to the polymerization vessel after the first polymerization is a short-chain alkylaluminum compound having only alkyl groups having 5 or less carbon atoms.

[0021] (XI) The method for producing a cyclic olefin copolymer according to any one of (I) to (IX), wherein both alkylaluminum compound I and alkylaluminum compound II different from alkylaluminum compound I are used as alkylaluminum compounds from the start of the first polymerization to the end of the second polymerization, wherein alkylaluminum compound I has at least one alkyl group having 6 or more carbon atoms, and alkylaluminum compound II has at least one alkyl group having 5 or less carbon atoms.

[0022] (XII) The method for producing a cyclic olefin copolymer according to (X), wherein the alkyl aluminum compound is at least one selected from the group consisting of trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, and tri-n-octylaluminum.

[0023] (XIII) The method for producing a cyclic olefin copolymer according to (XI), wherein the alkyl aluminum compound I is tri-n-octylaluminum, and the alkyl aluminum compound II is trimethylaluminum, triethylaluminum, or triisobutylaluminum.

[0024] (XIV) The method for producing a cyclic olefin copolymer according to any one of (X) to (XIII), wherein the amount of the obtained cyclic olefin copolymer is 200 g or more per 1 g of titanocene catalyst, and the number average molecular weight of the obtained cyclic olefin copolymer is 10,000 to 100,000.

[0025] (XV) The titanocene catalyst is represented by the following formula (1): (In formula (1), R １ ~R ３ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and R ４ and R ５ are each independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom; R ６ ~R １３ and each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a silyl group which may have, as a substituent, a monovalent hydrocarbon group having 1 to 12 carbon atoms.

[0026] (XVI) The method for producing a cyclic olefin copolymer according to any one of (I) to (XV), wherein the cyclic olefin copolymer has two or more glass transition temperatures within the range of 0 to 300°C.

[0027] According to the present invention, there can be provided a method for producing a cyclic olefin copolymer, which can efficiently produce a cyclic olefin copolymer which is a copolymer of a cyclic olefin monomer and an α-olefin monomer having 3 to 20 carbon atoms and has excellent toughness.

[0028] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

[0029] <Cyclic Olefin Copolymer> The cyclic olefin copolymer produced by the production method described below is an addition polymer of a cyclic olefin monomer and an α-olefin monomer having 3 to 20 carbon atoms. The above cyclic olefin copolymer has excellent toughness. In the specification of the present application, "toughness (of the cyclic olefin copolymer)" refers to a property evaluated by the number of times (folding endurance) a film can be bent until it breaks, as determined by a folding endurance test (MIT test). The higher the folding endurance number, the higher the toughness of the cyclic olefin copolymer (including molded articles thereof). The folding endurance test is performed by the method shown in the examples.

[0030] The ratio of the number of moles of structural units derived from α-olefin monomers to the number of moles of all structural units in the cyclic olefin copolymer is not particularly limited, and is preferably 10 to 50 mol%, more preferably 20 to 40 mol%, and even more preferably 20 to 30 mol%. When the cyclic olefin copolymer has structural units derived from α-olefin monomers in the above ratio, the cyclic olefin copolymer has high tensile strength and tensile modulus, a high glass transition temperature, and excellent heat resistance. The ratio of the number of moles of structural units derived from α-olefin monomers is １３ It can be calculated by measuring the C-NMR spectrum.

[0031] The cyclic olefin copolymer may contain structural units other than the structural units derived from the cyclic olefin monomer and the structural units derived from the α-olefin monomer having 3 to 20 carbon atoms, as long as the object of the present invention is not impaired. As the other structural units, structural units derived from compounds copolymerizable with the cyclic olefin monomer and the α-olefin monomer having 3 to 20 carbon atoms and having a carbon-carbon unsaturated double bond can be used. Typically, structural units derived from ethylene are preferred as the other structural units.

[0032] In the cyclic olefin copolymer, the sum of the ratio of the number of moles of structural units derived from cyclic olefin monomers and the ratio of the number of moles of structural units derived from α-olefin monomers relative to the number of moles of all structural units is preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and most preferably 100 mol%.

[0033] The cyclic olefin copolymer preferably has two or more glass transition temperatures within a range of 0 to 300°C. The glass transition temperature can be measured by observing the viscoelastic behavior of a 50 μm-thick film-shaped molded product at −100 to 300°C using a solid rheometer. Specifically, in the temperature range of 150°C to 300°C, the glass transition temperature is the peak-top temperature in the tan δ chart obtained by the above-mentioned measurement. In the temperature range of 0°C to less than 150°C, the point at which the value in the chart obtained by differentiating the loss modulus value obtained by the measurement with respect to temperature changes from positive to negative with increasing temperature, i.e., the maximum point of the loss modulus, is considered to be the peak, and the temperature at which the peak occurs is considered to be the glass transition temperature. In the present application, when a chart of values ​​obtained by differentiating loss modulus values ​​with respect to temperature in the temperature range of 0°C or higher and lower than 150°C does not have a point where the values ​​change from positive to negative as the temperature increases, that is, when the chart of loss modulus does not substantially have a maximum point, it is deemed that the material does not have a glass transition temperature in that temperature range.

[0034] Because the mechanical properties measured by a tensile test are good, the cyclic olefin copolymer preferably has at least one glass transition temperature in the range of 0 to 100°C and in the range of 160 to 300°C. In particular, because the breaking strain measured by a tensile test is large and the toughness is excellent, the cyclic olefin copolymer preferably has at least one glass transition temperature in the range below 0°C, the range of 0 to 100°C, and the range of 160 to 300°C. Within the above range of 0 to 100°C, the range of 30 to 80°C is preferred, and the range of 50 to 80°C is more preferred. Within the above range of 160 to 300°C, 170 to 280°C is preferred, and 170 to 260°C is more preferred. Within the above range of less than 0°C, -50 to 0°C is preferred, and -40 to -10°C is more preferred.

[0035] Typically, the cyclic olefin copolymer has one glass transition temperature in the range of 0 to 100°C and one glass transition temperature in the range of 160 to 300°C, or preferably has one glass transition temperature in the range below 0°C, one glass transition temperature in the range of 0 to 100°C, and one glass transition temperature in the range of 160 to 300°C.

[0036] The molecular weight of the cyclic olefin copolymer is not particularly limited. The weight average molecular weight (Mw) of the cyclic olefin copolymer, as measured by gel permeation chromatography (GPC) in terms of polystyrene, is preferably 5,000 to 200,000, more preferably 10,000 to 100,000. The number average molecular weight (Mn) of the cyclic olefin copolymer, as measured by gel permeation chromatography (GPC) in terms of polystyrene, is preferably 5,000 to 200,000, more preferably 10,000 to 100,000. Since the toughness of the cyclic olefin copolymer is excellent, it is preferable that the polydispersity ratio (Mw / Mn) is not excessively high. Specifically, the polydispersity ratio (Mw / Mn) is preferably 1.85 or less, more preferably 1.75 or less, and even more preferably 1.70 or less. The lower limit of the polydispersity ratio (Mw / Mn) is not particularly limited. The dispersion ratio (Mw / Mn) may be, for example, 1.1 or more.

[0037] <Cyclic Olefin Monomer> The cyclic olefin monomer is not particularly limited as long as it does not impair the object of the present invention. Typically, norbornene and substituted norbornene are preferably used as the cyclic olefin monomer. As the cyclic olefin monomer, norbornene is particularly preferred in terms of a good balance between cost, polymerizability, and the physical properties of the resulting cyclic olefin copolymer. The cyclic olefin monomer may be used alone or in combination of two or more.

[0038] The substituted norbornene is not particularly limited. Examples of the substituent on the substituted norbornene include a halogen atom and a monovalent or divalent hydrocarbon group. Specific examples of the substituted norbornene include a compound represented by the following formula (I):

[0039]

[0040] In formula (I), R ａ１ ~R ａ１２ R may be the same or different and are atoms or groups selected from the group consisting of hydrogen atoms, halogen atoms, and hydrocarbon groups. ａ９ and R ａ１０ , R ａ１１ and R ａ１２ may combine together to form a divalent hydrocarbon group. ａ９ or R ａ１０ And, R ａ１１ or R ａ１２ may be bonded to each other to form a ring. n is 0 or a positive integer. When n is 2 or more, R ａ５ ~R ａ８ may be the same or different in each repeating unit. However, when n is 0, R ａ１ ~R ａ４ and R ａ９ ~R ａ１２ At least one of is not a hydrogen atom.

[0041] R ａ１ ~R ａ８ Specific examples of R include a hydrogen atom; a halogen atom such as fluorine, chlorine, and bromine; and an alkyl group having 1 to 20 carbon atoms. ａ１ ~Rａ８ may all consist of different atoms or groups. ａ１ ~R ａ８ Some or all of these may be the same atom or group.

[0042] R ａ９ ~R ａ１２ Specific examples of R include a hydrogen atom; a halogen atom such as fluorine, chlorine, and 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, and an anthryl group; and an aralkyl group such as a benzyl group and a phenethyl group. ａ９ ~R ａ１２ may all consist of different atoms or groups. ａ９ ~R ａ１２ Some or all of these may be the same atom or group.

[0043] R ａ９ and R ａ１０ , or R ａ１１ and R ａ１２ Specific examples of divalent hydrocarbon groups that can be formed by combining these groups include alkylidene groups such as an ethylidene group, a propylidene group, and an isopropylidene group.

[0044] R ａ９ or R ａ１０ And, R ａ１１ or R ａ１２ When these bond to each other to form a ring, the ring formed may be a monocyclic or polycyclic ring. The ring formed may be a polycyclic ring having a bridge. The ring formed may have a double bond. The ring formed may have a substituent such as a methyl group.

[0045] Specific examples of the substituted norbornene represented by 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-bicyclo[2.2.1]hept-2-ene, 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-hexyl-bicyclo[2.2.1]hept-2-ene, 5-methyl ... Bicyclic olefins such as cyclo[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 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 .1７，１０ ] 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 .0１２，１７ .1 １３，ｌ６ ]-14-eicosene; polycyclic olefins such as a tetramer of cyclopentadiene.

[0046] Among these, alkyl-substituted norbornenes such as bicyclo[2.2.1]hept-2-ene substituted with one or more alkyl groups, and alkylidene-substituted norbornenes such as bicyclo[2.2.1]hept-2-ene substituted with one or more alkylidene groups are preferred, with 5-ethylidene-bicyclo[2.2.1]hept-2-ene (common name: 5-ethylidene-2-norbornene, or simply ethylidenenorbornene) being particularly preferred.

[0047] <α-Olefin Monomer> The α-olefin monomer is an α-olefin monomer having 3 to 20 carbon atoms. As such an α-olefin monomer, not only unsubstituted α-olefin monomers but also substituted α-olefin monomers having a substituent such as a halogen atom can be used. The number of carbon atoms in the α-olefin monomer is 3 to 20, preferably 4 to 12, and more preferably 6 to 10.

[0048] Specific examples of the α-olefin monomer having 3 to 12 carbon atoms 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. Among these, 1-hexene, 1-octene, and 1-decene are preferred, and 1-hexene and 1-octene are more preferred.

[0049] The above-mentioned cyclic olefin copolymer may be mixed with various additives as needed, and then molded into, for example, a film, a sheet, etc., and used in a wide variety of applications such as packaging, optical applications, etc. Examples of additives that can be added to the cyclic olefin copolymer include antioxidants, weather stabilizers, ultraviolet absorbers, antibacterial agents, flame retardants, colorants, etc. These additives are added to the cyclic olefin copolymer in amounts taking into account the typical amounts used depending on the type of additive.

[0050] <<Method for Producing Cyclic Olefin Copolymer>> Hereinafter, a method for producing a cyclic olefin copolymer will be described.

[0051] In the method for producing a cyclic olefin copolymer described below, a cyclic olefin copolymer having units derived from a cyclic olefin monomer and units derived from an α-olefin monomer having 3 to 20 carbon atoms is produced. The cyclic olefin copolymer is as described above.

[0052] The above production method includes: a first polymerization in which monomers including a cyclic olefin monomer and an α-olefin monomer are polymerized in a polymerization vessel in the presence of a titanocene catalyst, an alkylaluminum compound, and a borate compound; adding the alkylaluminum compound alone to the polymerization vessel after the first polymerization; and a second polymerization in which, after the addition of the alkylaluminum compound, additional monomers are added to the polymerization vessel and the monomers are subsequently polymerized. In the first polymerization, polymerization of the monomers is carried out until the reaction rate of the cyclic olefin monomer becomes 80 mol % or more based on the total number of moles of the cyclic olefin monomer added to the polymerization vessel at the start of the first polymerization and during the first polymerization, and the reaction rate of the α-olefin monomer becomes 80 mol % or more based on the total number of moles of the α-olefin monomer added to the polymerization vessel at the start of the first polymerization and during the first polymerization.

[0053] The above method can efficiently produce a cyclic olefin copolymer, which is a copolymer of a cyclic olefin monomer and an α-olefin monomer having 3 to 20 carbon atoms and has excellent toughness. Specifically, the amount of the cyclic olefin copolymer obtained can be 200 g or more, preferably 230 g or more, and more preferably 250 g or more per gram of titanocene catalyst.

[0054] The first polymerization, the addition of the alkylaluminum compound, and the second polymerization will be described below.

[0055] <First Polymerization> In the first polymerization, monomers including a cyclic olefin monomer and an α-olefin monomer are polymerized in a polymerization vessel in the presence of a titanocene catalyst, an alkylaluminum compound, and a borate compound. In the first polymerization, polymerization of the monomers is carried out until the reaction rate of the cyclic olefin monomer reaches 80 mol% or more relative to the total number of moles of the cyclic olefin monomer added to the polymerization vessel at the start of the first polymerization and during the first polymerization, and the reaction rate of the α-olefin monomer reaches 80 mol% or more relative to the total number of moles of the α-olefin monomer added to the polymerization vessel at the start of the first polymerization and during the first polymerization. In this case, a cyclic olefin copolymer having at least one glass transition temperature each in the range of less than 0°C, 0 to 100°C, and 160 to 300°C and having excellent toughness is easily obtained.

[0056] The monomers including the cyclic olefin monomer and the α-olefin monomer are as described above. As will be described later, in producing the cyclic olefin copolymer, monomers are added to a polymerization vessel in both the first polymerization and the second polymerization. The total amount of monomers added to the polymerization vessel in the first polymerization is preferably 20 to 80 mol %, more preferably 30 to 70 mol %, and even more preferably 40 to 60 mol %, based on the total number of moles of monomers used in producing the cyclic olefin copolymer.

[0057] During the first polymerization, the monomer may be added to the polymerization vessel in multiple portions. The number of times the monomer is added during the first polymerization is not particularly limited, but is preferably 1 to 5 times, more preferably 1 to 3 times, and even more preferably 1 or 2 times. When the monomer is added in portions during the first polymerization, the amount of the monomer added per portion is preferably TA / N×0.5 to TA / N×1.5, more preferably TA / N×0.7 to TA / N×1.3, and even more preferably TA / N×0.9 to TA / N×1.1, where TA is the total number of moles of the monomer added in the first polymerization and N is the number of portions.

[0058] When the monomers are added in portions during the first polymerization, only the cyclic olefin monomer or only the α-olefin monomer may be added in the second or subsequent additions. However, when the first polymerization is started, both the cyclic olefin monomer and the α-olefin monomer are always present in the polymerization vessel.

[0059] In the case where the monomer is added in portions during the first polymerization, the time from the time when the monomer is added in any one of a plurality of portions to the time when the next monomer is added is preferably TT / N×0.5 to TT / N×1.5, more preferably TT / N×0.7 to TT / N×1.3, and still more preferably TT / N×0.9 to TT / N×1.1, where TT is the total time of the first polymerization and N is the number of portions.

[0060] [Titanocene Catalyst] The titanocene catalyst is not particularly limited as long as it is a titanocene catalyst that can copolymerize a cyclic olefin monomer and an α-olefin monomer having 3 to 20 carbon atoms. Typically, the titanocene catalyst is appropriately selected from known titanocene catalysts that can copolymerize a cyclic olefin monomer and an α-olefin monomer having 3 to 20 carbon atoms. As the titanocene catalyst, one type may be used alone, or two or more types may be used in combination.

[0061] A preferred titanocene catalyst is a titanocene catalyst represented by the following formula (1): (In formula (1), R １ ~R ３are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and R ４ and R ５ are each independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom; R ６ ~R １３ are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a silyl group which may have a monovalent hydrocarbon group having 1 to 12 carbon atoms as a substituent.

[0062] In formula (1), R １ ~R ３ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms. Specific examples thereof include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, a hexyl group, a cyclopentyl group, and a cyclohexyl group; and aryl groups such as a phenyl group, a biphenyl group, a phenyl group or a biphenyl group having the above alkyl group as a substituent, a naphthyl group, and a naphthyl group having the above alkyl group as a substituent.

[0063] R ４ and R ５ are each independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, and specific examples thereof include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom; a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a cyclopentyl group, a cyclohexyl group, or any of these alkyl groups having the above-mentioned halogen atom as a substituent; a phenyl group, a biphenyl group, a naphthyl group, or any of these aryl groups having the above-mentioned halogen atom or alkyl group as a substituent.

[0064] R ６ ~R １３are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a silyl group which may have a monovalent hydrocarbon group having 1 to 12 carbon atoms as a substituent. Specific examples of the alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a cyclopentyl group, and a cyclohexyl group. Specific examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a biphenyl group, a naphthyl group, and any of these aryl groups having the above alkyl group as a substituent. Furthermore, specific examples of the silyl group having a monovalent hydrocarbon group having 1 to 12 carbon atoms as a substituent include silyl groups having an alkyl group having 1 to 12 carbon atoms as a substituent, such as a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, cyclopentyl group, and cyclohexyl group.

[0065] Specific examples of the titanocene catalyst represented by the general formula (1) include (isopropylamido)dimethyl-9-fluorenylsilanetitanium dimethyl, (isobutylamido)dimethyl-9-fluorenylsilanetitanium dimethyl, (t-butylamido)dimethyl-9-fluorenylsilanetitanium dimethyl, (isopropylamido)dimethyl-9-fluorenylsilanetitanium dichloride, (isobutylamido)dimethyl-9-(3,6-dimethylfluorenyl)silanetitanium dichloride, (t-butylamido)dimethyl-9-fluorenylsilanetitanium dichloride, ( (isopropylamido)dimethyl-9-(3,6-dimethylfluorenyl)silanetitanium dichloride, (isobutylamido)dimethyl-9-(3,6-dimethylfluorenyl)silanetitanium dichloride, (t-butylamido)dimethyl-9-(3,6-dimethylfluorenyl)silanetitanium dimethyl, (isopropylamido)dimethyl-9-[3,6-di(i-propyl)fluorenyl]silanetitanium dichloride, (isobutylamido)dimethyl-9-[3,6-di(i-propyl)fluorenyl]silanetitanium dichloride, (t-butylamido)dimethyl t-butylamido)dimethyl-9-[3,6-di(t-butyl)fluorenyl]silanetitanium dimethyl, (isopropylamido)dimethyl-9-[3,6-di(t-butyl)fluorenyl]silanetitanium dichloride, (isobutylamido)dimethyl-9-[3,6-di(t-butyl)fluorenyl]silanetitanium dichloride, (t-butylamido)dimethyl-9-[3,6-di(t-butyl)fluorenyl]silanetitanium dimethyl, (isopropylamido)dimethyl-9-[2,7-di(t-butyl)fluorenyl]silanetitanium dichloride, (isobutylamido)dimethyl

[0033] Examples of the silane titanium dichloride include (t-butylamido)dimethyl-9-[2,7-di(t-butyl)fluorenyl]silanetitanium dichloride, (t-butylamido)dimethyl-9-[2,7-di(t-butyl)fluorenyl]silanetitanium dimethyl, (isopropylamido)dimethyl-9-(2,3,6,7-tetramethylfluorenyl)silanetitanium dichloride, (isobutylamido)dimethyl-9-(2,3,6,7-tetramethylfluorenyl)silanetitanium dichloride, (t-butylamido)dimethyl-9-(2,3,6,7-tetramethylfluorenyl)silanetitanium dimethyl, and the like.Preferably, (t-butylamido)dimethyl-9-fluorenylsilanetitanium dimethyl ((t-BuNSiMe. ２ Flu)TiMe ２ ) (t-BuNSiMe ２ Flu)TiMe ２ is a titanium complex represented by the following formula (2), and can be easily synthesized, for example, based on the description in "Macromolecules, Vol. 31, p. 3184, 1998."

[0066] (In the formula, Me represents a methyl group, and t-Bu represents a tert-butyl group.)

[0067] The amount of the titanocene catalyst used is not particularly limited as long as the addition polymerization reaction proceeds smoothly. The amount of the titanocene catalyst used is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, and even more preferably 0.1 to 1 part by mass, per 100 parts by mass of the total amount of the cyclic olefin monomer and the α-olefin monomer.

[0068] The titanocene catalyst may be added to the polymerization vessel after the initiation of the first polymerization, other than at the initiation of the first polymerization. However, it is preferred that the entire amount of the titanocene catalyst used for producing the cyclic olefin copolymer is charged into the polymerization vessel at the initiation of the first polymerization.

[0069] [Alkyl aluminum compound] The first polymerization is carried out in the presence of a titanocene catalyst, an alkyl aluminum compound, and a borate compound. In the first polymerization, the alkyl aluminum compound charged into a polymerization vessel at the start of polymerization acts as a scavenger that captures water, oxygen, and other impurities.

[0070] In the first polymerization, the alkylaluminum compound charged into the polymerization vessel at the start of polymerization can be any alkylaluminum compound that has been conventionally used in the homopolymerization or copolymerization of cyclic olefin monomers, without any particular limitation. In the first polymerization, the alkylaluminum compound may be used alone or in combination of two or more.

[0071] In the first polymerization, suitable examples of the alkylaluminum compound to be charged into the polymerization vessel at the start of polymerization include trialkylaluminum, dialkylaluminum halide, dialkylaluminum hydride, dialkylaluminum alkoxide, etc. Among these, trialkylaluminum is preferred.

[0072] Specific preferred examples of trialkylaluminum include trimethylaluminum, triethylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-sec-butylaluminum, tri-n-octylaluminum, etc. Among these, triisobutylaluminum and tri-n-octylaluminum are preferred.

[0073] Specific examples of suitable dialkylaluminum halides include dimethylaluminum chloride and diisobutylaluminum chloride.

[0074] A specific example of a suitable dialkylaluminum hydride is diisobutylaluminum hydride.

[0075] A specific example of a suitable dialkylaluminum alkoxide is dimethylaluminum methoxide.

[0076] In the first polymerization, the alkylaluminum compound charged into the polymerization vessel at the start of the polymerization is preferably a long-chain alkylaluminum compound having only alkyl groups having 6 or more carbon atoms. The long-chain alkylaluminum compound acts well as a scavenger.

[0077] The amount of the alkylaluminum compound used in the first polymerization is preferably 10 to 5,000 parts by mass, more preferably 100 to 1,000 parts by mass, per 100 parts by mass of the total amount of the titanocene catalyst used in the first polymerization.

[0078] During the first polymerization, the alkylaluminum compound may be added to the polymerization vessel in multiple portions. However, when the alkylaluminum compound is added during the first polymerization, the alkylaluminum compound is added to the polymerization vessel together with other materials. Typically, when the alkylaluminum compound is added during the first polymerization, the alkylaluminum compound is added to the polymerization vessel together with the monomer. The number of times the alkylaluminum compound is added during the first polymerization is not particularly limited, but is preferably 1 to 5 times, more preferably 1 to 3 times, and even more preferably 1 or 2 times. When the alkylaluminum compound is added in portions during the first polymerization, the amount of the alkylaluminum compound added per portion is preferably TA / N x 0.5 to TA / N x 1.5, more preferably TA / N x 0.7 to TA / N x 1.3, and even more preferably TA / N x 0.9 to TA / N x 1.1, where TA is the total number of moles of the alkylaluminum compound added in the first polymerization and N is the number of portions. When the alkylaluminum compound is added in portions during the first polymerization, the timing of addition of the alkylaluminum compound may be the same as or different from the timing of addition of the monomers, and is preferably the same.

[0079] [Borate Compound] The first polymerization is carried out in the presence of a titanocene catalyst, an alkylaluminum compound, and a borate compound. As the borate compound, any borate compound that has been conventionally used as a co-catalyst in the homopolymerization or copolymerization of a cyclic olefin monomer can be used without any particular limitation. In the first polymerization, one borate compound may be used alone, or two or more borate compounds may be used in combination.

[0080] Specific preferred examples of the borate compound include triphenylmethylium tetrakis(pentafluorophenyl)borate, dimethylphenylammonium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, and N-methyldin-normal-decylammonium tetrakis(pentafluorophenyl)borate.

[0081] The amount of the borate compound used in the first polymerization is not particularly limited as long as the addition polymerization reaction proceeds smoothly and a cyclic olefin copolymer having desired properties is obtained. The amount of the borate compound used is preferably 250 to 750 parts by mass, and more preferably 350 to 500 parts by mass, per 100 parts by mass of the total amount of the titanocene catalyst used in the production of the cyclic olefin copolymer.

[0082] The borate compound may be added to the polymerization vessel after the initiation of the first polymerization, other than at the initiation of the first polymerization. However, it is preferred that the entire amount of the borate compound used in the production of the cyclic olefin copolymer is charged into the polymerization vessel at the initiation of the first polymerization.

[0083] [Other Components] In the first polymerization, the polymerization of the aforementioned monomers may be carried out in the presence of other components besides the alkylaluminum compound and the borate compound, as long as the object of the present invention is not impaired. A suitable example of such other component is a hindered phenol. As the hindered phenol, any hindered phenol that has conventionally been used as a co-catalyst in the homopolymerization or copolymerization of cyclic olefin monomers can be used without particular limitation. Here, the hindered phenol refers to a phenol having a bulky substituent on at least one of the two adjacent positions to the phenolic hydroxyl group. Examples of the bulky substituent include alkyl groups other than methyl groups, such as isopropyl, isobutyl, sec-butyl, and tert-butyl groups, alkenyl groups, alkynyl groups, aryl groups, heterocyclic groups, alkoxy groups, aryloxy groups, substituted amino groups, alkylthio groups, and arylthio groups.

[0084] Specific examples of hindered phenols include 2,6-di-tert-butyl-4-hydroxytoluene (BHT), 2,6-di-tert-butylphenol, 2-tert-butylphenol, 2-tert-butyl-p-cresol, 3,3',5,5'-tetra-tert-butyl-4,4'-dihydroxybiphenyl, and 3,3',5,5'-tetra-tert-butyl-2,2'-dihydroxybiphenyl. Examples of suitable hindered phenols include 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-4-hydroxytoluene (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 of them.

[0085] The amount of hindered phenol used in the first polymerization is not particularly limited, as long as the addition polymerization reaction proceeds smoothly and a cyclic olefin copolymer with the desired properties is obtained. The amount of hindered phenol used is preferably 1 to 1,000 parts by mass, more preferably 10 to 500 parts by mass, and even more preferably 100 to 200 parts by mass, relative to 100 parts by mass of the total amount of titanocene catalyst used in the production of the cyclic olefin copolymer. The relationship between the amount of hindered phenol used and the amount of alkylaluminum compound used is not particularly limited, as long as the desired effect is not impaired. The amount of hindered phenol used is preferably such that the amount of phenolic hydroxyl groups in the hindered phenol is 1.5 mol or less per mole of alkylaluminum compound. The amount of phenolic hydroxyl groups in the hindered phenol per mole of alkylaluminum compound is more preferably 1.4 mol or less, even more preferably 1.3 mol or less, and particularly preferably 1.2 mol or less. When the amount of hindered phenol used relative to the alkylaluminum compound is within the above range, the chain transfer reaction of the alkylaluminum compound is less likely to be inhibited.

[0086] <Solvent> The first polymerization may be carried out in the presence of a solvent. The first polymerization is typically carried out in the presence of a solvent. The solvent is not particularly limited as long as it does not inhibit the polymerization reaction. Preferred solvents include, for example, hydrocarbon solvents and halogenated hydrocarbon solvents, and hydrocarbon solvents are preferred because of their excellent handleability, thermal stability, and chemical stability. Specific examples of preferred solvents include hydrocarbon solvents such as pentane, hexane, heptane, octane, isooctane, isododecane, mineral oil, cyclohexane, methylcyclohexane, decahydronaphthalene (decalin), benzene, toluene, and xylene, and halogenated hydrocarbon solvents such as chloroform, methylene chloride, dichloromethane, dichloroethane, and chlorobenzene.

[0087] The solvent may be charged into the polymerization vessel alone, or may be charged into the polymerization vessel in the form of a monomer solution, a catalyst solution, or a cocatalyst solution.

[0088] When a solvent is used, the amount thereof is not particularly limited and is preferably 100 to 100,000 parts by mass, more preferably 500 to 10,000 parts by mass, and even more preferably 1,000 parts by mass or more and 5,000 parts by mass or less, relative to 100 parts by mass of the total amount of the monomers used in the first polymerization.

[0089] <Reaction Conditions> The polymerization temperature in the first polymerization is not particularly limited. The polymerization temperature is, for example, preferably −20 to 40°C, more preferably −10 to 20°C, and even more preferably −5 to 10°C. The time for the first polymerization is not particularly limited, as long as the polymerization proceeds until a predetermined amount of monomer is consumed. In the first polymerization, the monomers are polymerized until the reaction rate of the cyclic olefin monomer becomes 80 mol% or more relative to the total number of moles of the cyclic olefin monomer added to the polymerization vessel at the start of the first polymerization and during the first polymerization, and the reaction rate of the α-olefin monomer becomes 80 mol% or more relative to the total number of moles of the α-olefin monomer added to the polymerization vessel at the start of the first polymerization and during the first polymerization. Typically, the time for the first polymerization is, for example, preferably 8 to 30 minutes, more preferably 10 to 25 minutes, and even more preferably 15 to 20 minutes. The monomer may be added to the polymerization vessel in multiple batches. In this case, in the first polymerization, as long as the reactivity of the cyclic olefin monomer and the reactivity of the α-olefin monomer are each 80 mol% or more relative to the total number of moles of cyclic olefin monomer or the total number of moles of α-olefin monomer added into the polymerization vessel at the start of the first polymerization and during the first polymerization, the reactivity of the cyclic olefin monomer and the reactivity of the α-olefin monomer from the start of the first polymerization until before the second monomer addition in the first polymerization, the reactivity of the cyclic olefin monomer and the reactivity of the α-olefin monomer from the mth monomer addition to the (m+1)th monomer addition, and the reactivity of the cyclic olefin monomer and the reactivity of the α-olefin monomer from the final monomer addition to the end of the first polymerization are not particularly limited, and are preferably 80 mol% or more. Here, m is any integer of 1 or more. When the number of monomer additions during the first polymerization is one, the (m+1)th monomer addition is not performed, and the mth monomer addition is the final monomer addition.In the first polymerization, the reactivity of the cycloolefin monomer or the reactivity of the α-olefin monomer relative to the total number of moles of the cycloolefin monomer or the total number of moles of the α-olefin monomer added into the polymerization vessel at the start of the first polymerization and during the first polymerization can be calculated by measuring the amount of the cycloolefin monomer or the amount of the α-olefin monomer remaining in the polymerization vessel at the end of the first polymerization, respectively. The reactivity of the cycloolefin monomer and the reactivity of the α-olefin monomer from the start of the first polymerization until the second monomer addition in the first polymerization is determined based on the number of moles of the cycloolefin monomer charged into the polymerization vessel before the start of the first polymerization, or the number of moles of the cycloolefin monomer charged into the polymerization vessel before the start of the first polymerization. The reactivity of the cycloolefin monomer and the reactivity of the α-olefin monomer from the mth monomer addition to the (m+1)th monomer addition is determined based on the number of moles of the cycloolefin monomer or the number of moles of the α-olefin monomer in the polymerization vessel immediately after the mth monomer addition. The number of moles of cyclic olefin monomer or the number of moles of α-olefin monomer in the polymerization vessel immediately after the mth monomer addition is the sum of the number of moles of cyclic olefin monomer or the number of moles of α-olefin monomer in the polymerization vessel immediately before the mth monomer addition and the number of moles of cyclic olefin monomer or the number of moles of α-olefin monomer added to the polymerization vessel by the mth monomer addition. The reaction rate of cyclic olefin monomer or α-olefin monomer from the addition of the last monomer to the end of the first polymerization is determined based on the number of moles of cyclic olefin monomer or the number of moles of α-olefin monomer in the polymerization vessel immediately after the last monomer addition. The number of moles of cyclic olefin monomer or the number of moles of α-olefin monomer in the polymerization vessel immediately after the last monomer addition is the sum of the number of moles of cyclic olefin monomer or the number of moles of α-olefin monomer in the polymerization vessel immediately before the last monomer addition and the number of moles of cyclic olefin monomer or the number of moles of α-olefin monomer added to the polymerization vessel by the last monomer addition.

[0090] The atmosphere in which the first polymerization reaction is carried out is not particularly limited, but an inert gas atmosphere is preferred, and examples of the inert gas that can be used include nitrogen gas and helium gas.

[0091] As described above, in the first polymerization, the titanocene catalyst, the alkylaluminum compound, the borate compound, the other components, and the monomers may each be added to the polymerization vessel in two or more divided portions, provided that in the first polymerization, polymerization of the monomers is always initiated in the presence of the titanocene catalyst, the alkylaluminum compound, and the borate compound.

[0092] <Addition of alkylaluminum compound> After the first polymerization, the alkylaluminum compound is added alone to the polymerization vessel. However, it is permissible to add a component inactive to the polymerization reaction, such as an organic solvent, together with the alkylaluminum compound after the first polymerization step. In other words, the addition of the alkylaluminum compound together with a component active in the polymerization reaction, such as a monomer, catalyst, or cocatalyst, does not fall under the category of adding the alkylaluminum compound alone after the first polymerization. The alkylaluminum compound added to the polymerization vessel after the first polymerization acts as a chain transfer agent. By carrying out the second polymerization described below in the presence of an alkylaluminum compound acting as a chain transfer agent, the yield of the cyclic olefin copolymer per unit weight of the titanocene catalyst can be increased without excessively increasing the dispersity ratio of the molecular weight of the resulting cyclic olefin copolymer.

[0093] The alkylaluminum compound added to the polymerization vessel after the first polymerization can be the same as the alkylaluminum compound used in the first polymerization. The alkylaluminum compound added to the polymerization vessel after the first polymerization may be the same as or different from the alkylaluminum compound used in the first polymerization. The alkylaluminum compounds added to the polymerization vessel after the first polymerization may be used alone or in combination of two or more.

[0094] Specific preferred examples of the trialkylaluminum to be added to the polymerization vessel after the first polymerization include trimethylaluminum, triethylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-sec-butylaluminum, tri-n-octylaluminum, etc. Among these, trimethylaluminum and triethylaluminum are preferred.

[0095] The alkylaluminum compound added to the polymerization vessel after the first polymerization is preferably a short-chain alkylaluminum compound having only alkyl groups having 5 or less carbon atoms. Short-chain alkylaluminum compounds function well as chain transfer agents. Therefore, when a short-chain alkylaluminum compound is used as the alkylaluminum compound added to the polymerization vessel after the first polymerization, a cyclic olefin copolymer having particularly excellent heat resistance and toughness is easily obtained, and the yield of the cyclic olefin copolymer per unit weight of the titanocene catalyst is easily increased.

[0096] As described above, the purpose of use of the alkylaluminum compound charged into the polymerization vessel at the start of the first polymerization differs from the purpose of use of the alkylaluminum compound added into the polymerization vessel after the first polymerization. For these reasons, it is preferable to use both alkylaluminum compound I and alkylaluminum compound II, which is different from alkylaluminum compound I, from the start of the first polymerization to the end of the second polymerization. As described below, the second polymerization may be repeated multiple times. When the second polymerization is repeated multiple times, the "end of the second polymerization" in the above "from the start of the first polymerization to the end of the second polymerization" refers to the end of the last second polymerization. The alkylaluminum compound I and the alkylaluminum compound II may each be added to the polymerization vessel at any time between the start of the first polymerization and the end of the last second polymerization. The alkylaluminum compound I has at least one alkyl group having 6 or more carbon atoms. The alkylaluminum compound II has at least one alkyl group having 5 or fewer carbon atoms. For example, the alkylaluminum compound I may be added to the polymerization vessel at the start of the first polymerization, and the alkylaluminum compound II may be added to the polymerization vessel at any time after the first polymerization. Alternatively, alkylaluminum compound II may be added to the polymerization vessel at the start of the first polymerization, and alkylaluminum compound I may be added to the polymerization vessel at any time after the first polymerization. Furthermore, alkylaluminum compound I and alkylaluminum compound II may be added simultaneously to the polymerization vessel at the start of the first polymerization, or a mixture of alkylaluminum compound I and alkylaluminum compound II may be added to the polymerization vessel. In this case, any alkylaluminum compound may be added to the polymerization vessel at any time after the first polymerization, and alkylaluminum compound II is preferably added to the polymerization vessel at any time after the first polymerization. The alkylaluminum compound I has at least one alkyl group having 6 or more carbon atoms. The alkylaluminum compound II has at least one alkyl group having 5 or fewer carbon atoms.

[0097] Alkyl aluminum compound I preferably has two or three alkyl groups having 6 or more carbon atoms, and more preferably has three alkyl groups having 6 or more carbon atoms. Alkyl aluminum compound II preferably has two or three alkyl groups having 5 or less carbon atoms, and more preferably has three alkyl groups having 5 or less carbon atoms. Alkyl aluminum compound I and alkyl aluminum compound II may each be a dialkyl aluminum halide, dialkyl aluminum hydride, or dialkyl aluminum alkoxide.

[0098] In the first polymerization and the second polymerization, when two types of alkylaluminum compounds, one having an alkyl group with 6 or more carbon atoms and the other having 5 or less carbon atoms, are used as the alkylaluminum compound, either of the alkylaluminum compounds may be alkylaluminum compound I, and either of the alkylaluminum compounds may be alkylaluminum compound II.

[0099] When both the alkylaluminum compound I and the alkylaluminum compound II are used as alkylaluminum compounds in the first and second polymerizations, the molar ratio of alkylaluminum compound I to alkylaluminum compound II is preferably 2:8 to 8:2, more preferably 3:7 to 7:3, and even more preferably 4:6 to 6:4.

[0100] As will be described in detail later, the addition of the alkylaluminum compound after the first polymerization and the second polymerization may be repeated, i.e., the alkylaluminum compound may be added to the polymerization vessel multiple times after the first polymerization.

[0101] The total amount of alkylaluminum compound added to the polymerization vessel after the first polymerization is preferably 1 to 1,000 parts by mass, and more preferably 10 to 100 parts by mass, relative to 100 parts by mass of the total amount of the titanocene catalyst used in the production of the cyclic olefin copolymer. When alkylaluminum compound is added multiple times after the first polymerization, the amount of alkylaluminum compound added per addition is preferably TA / N x 0.5 to TA / N x 1.5, more preferably TA / N x 0.7 to TA / N x 1.3, and even more preferably TA / N x 0.9 to TA / N x 1.1, where TA is the total number of moles of alkylaluminum compound added after the first polymerization and N is the number of divisions.

[0102] <Second Polymerization> After the first polymerization, an alkylaluminum compound is added, and then monomers are added to the polymerization vessel, followed by the second polymerization, in which the monomers are subsequently polymerized. In the second polymerization, the composition of the monomers added to the polymerization vessel may be the same as or different from the composition of the monomers in the first polymerization, but is preferably the same. In the second polymerization, only cyclic olefin monomers or only α-olefin monomers may be added as monomers, but it is preferred to add monomers containing cyclic olefin monomers and α-olefin monomers.

[0103] As will be described in detail later, the addition of the alkylaluminum compound and the second polymerization carried out after the first polymerization may be carried out repeatedly, i.e., the second polymerization may be carried out multiple times after the first polymerization.

[0104] The total amount of the monomers added to the polymerization vessel in the second polymerization is preferably 20 to 80 mol %, more preferably 30 to 70 mol %, and even more preferably 40 to 60 mol %, based on the total number of moles of the monomers used in the production of the cyclic olefin copolymer.

[0105] The monomer may be added in multiple divided portions in the second polymerization when the second polymerization is carried out only once, or in at least one of the multiple second polymerizations when the second polymerization is carried out multiple times. When the monomer is added in divided portions in the second polymerization, the amount of the monomer added per division is preferably TA / N×0.5 to TA / N×1.5, more preferably TA / N×0.7 to TA / N×1.3, and still more preferably TA / N×0.9 to TA / N×1.1, where TA is the total number of moles of the monomer added in one second polymerization and N is the number of divisions.

[0106] In the second polymerization, it is also preferable to add an alkylaluminum compound together with the monomers. In this case, it is believed that the alkylaluminum compound acts as a scavenger that captures water, oxygen, and other impurities in the monomers. The amount of the alkylaluminum compound added together with the monomers is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 1 part by mass, per 100 parts by mass of the total amount of the monomers used in the second polymerization.

[0107] Regarding the reaction conditions in the second polymerization, the reaction temperature is the same as in the first polymerization. The reaction time is not particularly limited. The second polymerization may be continued until a desired amount of a cyclic olefin copolymer having desired physical properties is produced. Typically, the time for the second polymerization is, for example, preferably 5 to 300 minutes, more preferably 8 to 120 minutes, and even more preferably 10 to 60 minutes. When the second polymerization is repeatedly carried out multiple times, the polymerization time for the second polymerization is the total polymerization time for the multiple second polymerizations. When the second polymerization is repeatedly carried out multiple times, the polymerization time for each of the multiple second polymerizations is not particularly limited. When the second polymerization is carried out multiple times after the first polymerization, the time for each second polymerization is preferably TT / N×0.5 to TT / N×1.5, more preferably TT / N×0.7 to TT / N×1.3, and still more preferably TT / N×0.9 to TT / N×1.1, where TT is the total time for the multiple second polymerizations and N is the number of times the second polymerization is carried out.

[0108] In the method described above, the polymerization reaction may be terminated after the first polymerization, the addition of the alkylaluminum compound after the first polymerization, and the second polymerization. In this case, the number of steps is reduced, and the cyclic olefin copolymer can be easily produced.

[0109] When the polymerization reaction is terminated after the first polymerization, the addition of an alkylaluminum compound after the first polymerization, and the second polymerization, as described above, the monomer may be added in two or more divided portions in the first polymerization and / or the second polymerization. It is more preferable to add the monomer in two divided portions in the first polymerization and / or the second polymerization. It is preferable to add the monomer in two divided portions in both the first polymerization and the second polymerization. When the second polymerization is carried out only once, the reaction rates of the cyclic olefin monomer and the α-olefin monomer in the second polymerization are not particularly limited, but are preferably 80 mol% or more relative to the total number of moles of the cyclic olefin monomer added to the polymerization vessel at the start of the second polymerization and during the second polymerization, or the total number of moles of the α-olefin monomer added to the polymerization vessel at the start of the second polymerization and during the second polymerization. In this case, a cyclic olefin copolymer having excellent toughness and at least one glass transition temperature in the range of less than 0°C, 0 to 100°C, and 160 to 300°C is easily obtained. As described above, the monomer may be added to the polymerization vessel in multiple additions. In this case, the reactivity of the cycloolefin monomer and the α-olefin monomer from the start of the second polymerization until the second monomer addition in the second polymerization, the reactivity of the cycloolefin monomer and the α-olefin monomer from the mth monomer addition to the (m+1)th monomer addition, and the reactivity of the cycloolefin monomer and the α-olefin monomer from the last monomer addition to the end of the second polymerization are not particularly limited, and are preferably 80 mol% or more. Here, m is an arbitrary integer of 1 or more. When the number of monomer additions during the second polymerization is one, the (m+1)th monomer addition is not performed, and the mth monomer addition is the last monomer addition. The reactivity of the cycloolefin monomer and the α-olefin monomer from the start of the second polymerization until the second monomer addition in the second polymerization, or the reactivity of the α-olefin monomer, is determined based on the number of moles of the cycloolefin monomer or the number of moles of the α-olefin monomer present in the polymerization vessel at the start of the second polymerization.The number of moles of cyclic olefin monomer or the number of moles of α-olefin monomer present in the polymerization vessel at the start of the second polymerization is the sum of the number of moles of cyclic olefin monomer or the number of moles of α-olefin monomer remaining in the polymerization vessel after the first polymerization and the number of moles of cyclic olefin monomer or the number of moles of α-olefin monomer added to the polymerization vessel after the addition of the alkylaluminum compound and before the start of the second polymerization. The reaction rate of cyclic olefin monomer or the reaction rate of α-olefin monomer from the mth monomer addition to the (m+1)th monomer addition is determined based on the number of moles of cyclic olefin monomer in the polymerization vessel immediately after the mth monomer addition. The number of moles of cyclic olefin monomer in the polymerization vessel immediately after the mth monomer addition is the sum of the number of moles of cyclic olefin monomer in the polymerization vessel immediately before the mth monomer addition and the number of moles of cyclic olefin monomer added to the polymerization vessel by the mth monomer addition. The reaction rate of cyclic olefin monomer from the last monomer addition to the end of the second polymerization is determined based on the number of moles of cyclic olefin monomer in the polymerization vessel immediately after the last monomer addition. The number of moles of cyclic olefin monomer in the polymerization vessel immediately after the final monomer addition is the sum of the number of moles of cyclic olefin monomer in the polymerization vessel immediately before the final monomer addition and the number of moles of cyclic olefin monomer added to the polymerization vessel by the final monomer addition.

[0110] Furthermore, after the first second polymerization, the addition of the alkylaluminum compound and the second polymerization may be repeated until the number of alkylaluminum compound additions reaches n. The pth addition of the alkylaluminum compound among the 2nd to nth additions is carried out after the (p-1)th second polymerization. Here, n is an integer of 2 or more, and p is an integer of 2 or more and n or less. The pth addition of the alkylaluminum compound is carried out in the (p-1)th second polymerization after the reaction rate of the cycloolefin monomer in the polymerization vessel at the start of the (p-1)th second polymerization and the number of moles of the cycloolefin monomer added to the polymerization vessel during the (p-1)th second polymerization has reached 80 mol % or more, and the reaction rate of the α-olefin monomer has reached 80 mol % or more, based on the total number of moles of the α-olefin monomer in the polymerization vessel at the start of the (p-1)th second polymerization and the number of moles of the α-olefin monomer added to the polymerization vessel during the (p-1)th second polymerization. As described below, in at least one of the n second polymerizations, the monomer may be added to the polymerization vessel in two or more installments. For this reason, a cyclic olefin monomer and / or an α-olefin monomer may be added to the polymerization vessel during the second polymerization. The number of moles of cyclic olefin monomer or α-olefin monomer in the polymerization vessel at the start of the (p-1)th second polymerization is the sum of the number of moles of cyclic olefin monomer or α-olefin monomer remaining in the polymerization vessel at the end of the (p-2)th second polymerization and the number of moles of cyclic olefin monomer or α-olefin monomer added to the polymerization vessel immediately before the start of the (p-1)th second polymerization. The reaction rates of the cyclic olefin monomer and α-olefin monomer in the final second polymerization (the nth second polymerization) do not have to be 80 mol% or more relative to the total amount of cyclic olefin monomer or α-olefin monomer added to the polymerization vessel at the start of the final second polymerization and during the final second polymerization, respectively. In this method, the polymerization reaction is terminated after the nth second polymerization.

[0111] In this case, the monomer may be divided into two or more portions and added in portions to the polymerization vessel in at least one of the first polymerization and / or n number of second polymerizations, and it is preferred that the monomer be divided into two portions and added in portions to the polymerization vessel in at least one of the first polymerization and / or n number of second polymerizations. It is preferred that the monomer be divided into two portions and added in portions to the polymerization vessel in all of the first polymerization and n number of second polymerizations.

[0112] In the above-described method for producing a cyclic olefin copolymer, it is preferable that the amount of the cyclic olefin copolymer obtained is 200 g or more per 1 g of titanocene catalyst, and that the number average molecular weight of the cyclic olefin copolymer obtained is 10,000 to 100,000.

[0113] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0114] In the following examples and comparative examples, a titanocene catalyst having the following structure was used: In the following formula, Me is a methyl group, and t-Bu is a tert-butyl group.

[0115] Example 1 In Example 1, 2-norbornene (Nb) and 1-octene (Oct) were used in the ratios shown in Table 1, such that the total amount of 2-norbornene and 1-octene was 17.28 mmol.

[0116] (First Polymerization) 2-norbornene, ¼ of the amount of 1-octene, and 0.160 mmol of tri-n-octylaluminum were added to a 50 mL Schlenk flask purged with nitrogen. The contents of the flask were then diluted to a volume of 21.9 mL using decalin. The contents of the flask were then cooled to 0°C. After cooling, a toluene solution containing a titanocene catalyst at a concentration of 0.16 mmol / mL was added to the reaction solution so that the amount of titanocene catalyst was 0.016 mmol. Next, a toluene solution containing a borate compound at a concentration of 0.008 mmol / L was added to the reaction solution so that the amount of borate compound was 0.016 mmol. Triphenylmethylium tetrakis(pentafluorophenyl)borate was used as the borate compound. After initiating addition polymerization by adding the titanocene catalyst and the borate compound, the reaction was carried out at 0°C for 10 minutes while stirring the reaction solution with a magnetic stirrer. The reaction rate of 2-norbornene was 99 mol% relative to the number of moles of 2-norbornene at the start of polymerization, and the reaction rate of 1-octene was 95 mol% relative to the number of moles of 1-octene at the start of polymerization. After 10 minutes of reaction, 1 / 4 of the amounts of 2-norbornene and 1-octene, and 0.016 mmol of tri-n-octylaluminum were added to the Schlenk flask. The addition polymerization reaction was then continued for 10 minutes. After 10 minutes of reaction following the addition of the monomers, the reaction rate of 2-norbornene was 98 mol% relative to the number of moles of 2-norbornene at the time of addition of the monomers, and the reaction rate of 1-octene was 94 mol% relative to the number of moles of 1-octene at the start of polymerization.

[0117] (Addition of alkylaluminum compound) After 20 minutes of reaction, a toluene solution of triethylaluminum with a concentration of 0.1 mol / L was added to the Schlenk flask so that the amount of triethylaluminum was 0.032 mmol, thereby initiating a chain transfer reaction.

[0118] (Second Polymerization) After the initiation of the chain transfer reaction, 2-norbornene, ¼ of the amount of 1-octene, and 0.016 mmol of tri-n-octylaluminum were added to the Schlenk flask. The addition polymerization reaction was then continued for 25 minutes. The reaction rate of 2-norbornene at the end of the 25-minute reaction was 95 mol % relative to the number of moles of 2-norbornene at the initiation of the second polymerization, and the reaction rate of 1-octene was 93 mol % relative to the number of moles of 1-octene at the initiation of the polymerization.

[0119] After 25 minutes of reaction, 2-norbornene, ¼ of the amount of 1-octene, and 0.016 mmol of tri-n-octylaluminum were added to the Schlenk flask. The addition polymerization reaction was then continued for 25 minutes. The reaction rate of 2-norbornene after 25 minutes of reaction after the addition of the monomers was 90 mol % relative to the number of moles of 2-norbornene at the time of monomer addition, and the reaction rate of 1-octene was 85 mol % relative to the number of moles of 1-octene at the start of polymerization.

[0120] After a total of 70 minutes of reaction, a small amount of 2-propanol was added to the reaction solution to terminate the addition polymerization reaction. Hydrochloric acid was added to the reaction solution and stirred for 10 minutes, and then the organic layer was washed with ion-exchanged water. Washing with ion-exchanged water was repeated until the aqueous layer became neutral, and the washed organic layer was recovered. The recovered organic layer was added dropwise to a large amount of acetone to precipitate the produced cyclic olefin copolymer. The precipitated copolymer was recovered by filtration, and then washed twice or more with methanol and acetone. The washed copolymer was dried under reduced pressure at 110°C for 16 hours or more to obtain a dried cyclic olefin copolymer.

[0121] Example 2 A cyclic olefin copolymer was obtained in the same manner as in Example 1, except that tri-n-octylaluminum used in the first and second polymerizations was changed to triisobutylaluminum. The charging ratios of norbornene and 1-octene are as shown in Table 1. Table 2 shows the reaction rates of the monomers from the start of polymerization to the addition of the monomers, and the reaction rate of 2-norbornene from the addition of the monomers to the end of polymerization, in the first and second polymerizations.

[0122] After a total of 70 minutes of reaction, a cyclic olefin copolymer was obtained in the same manner as in Example 1.

[0123] [Examples 3 and 4] Cyclic olefin copolymers were obtained in the same manner as in Examples 1 and 2, respectively, except that 1-octene was replaced with 1-hexene (Hex). That is, the conditions in Example 3 were the same as those in Example 1, except for the type of monomer. Similarly, the conditions in Example 4 were the same as those in Example 2, except for the type of monomer.

[0124] A cyclic olefin copolymer was obtained in the same manner as in Example 1, except that in the first polymerization, the reaction solution was stirred with a magnetic stirrer for 5 minutes, and in the second polymerization, the reaction solution was stirred with a magnetic stirrer for 15 minutes. The charging ratios of norbornene and 1-octene were as shown in Table 1.

[0125] [Comparative Example 2] A cyclic olefin copolymer was obtained in the same manner as in Comparative Example 1, except that 1-octene was replaced with 1-hexene (Hex). Note that in Comparative Example 2, the reaction rates of the monomers in the first polymerization from the start of polymerization to the addition of the monomers were low. For this reason, Comparative Example 2 does not satisfy the requirement that the reaction rates of the cyclic olefin monomer and the α-olefin monomer in the first polymerization are both 80 mol% or more relative to the total number of moles of the cyclic olefin monomer or the total number of moles of the α-olefin monomer added to the polymerization vessel at the start of the first polymerization and during the first polymerization.

[0126] Comparative Example 3 A cyclic olefin copolymer was obtained in the same manner as in Example 1, except that the second polymerization was not carried out.

[0127] Comparative Example 4 A cyclic olefin copolymer was obtained in the same manner as in Comparative Example 3, except that 1-octene was replaced with 1-hexene (Hex).

[0128] Comparative Example 5 2-norbornene (Nb) and 1-octene (Oct) were used in the ratios shown in Table 1, in amounts such that the total amount of 2-norbornene and 1-octene was 118.8 mmol. 2-norbornene, 1-octene, 0.97 mmol of CC1 below, and 0.68 mmol of CC2 below were added to a 500 mL eggplant-shaped flask purged with nitrogen. The contents of the flask were then diluted with toluene to a volume of 258 mL. The contents of the flask were then heated to 40°C. After heating, a toluene solution containing a titanocene catalyst at a concentration of 0.04 mmol / L was added to the reaction solution so that the amount of titanocene catalyst was 0.22 mmol. After initiating addition polymerization by adding the titanocene catalyst, the reaction solution was stirred with a magnetic stirrer while the reaction was carried out at 40°C for 4 hours. After the 4-hour reaction, a cyclic olefin copolymer was obtained in the same manner as in Example 1.

[0129] CC1: 6.5 mass% (as Al atom content) MMAO-3A toluene solution ([(CH ３ ) ０．７ (iso-C ４ H ９ ) ０．３ AlO] ｎ CC1: a 9.0 mass% (as Al atom content) TMAO-211 toluene solution (a methylaluminoxane solution, manufactured by Tosoh Finechem Co., Ltd., containing 26 mol% trimethylaluminum based on the total Al). CC2: a 9.0 mass% (as Al atom content) TMAO-211 toluene solution (a methylaluminoxane solution, manufactured by Tosoh Finechem Co., Ltd., containing 26 mol% trimethylaluminum based on the total Al).

[0130] Comparative Example 6 A cyclic olefin copolymer was obtained in the same manner as in Comparative Example 5, except that 1-octene was changed to 1-hexene (Hex).

[0131] The polymerization conditions in each Example and Comparative Example are shown in Tables 1 and 2 below. The reaction rates of the cyclic olefin monomer (2-norbornene) and the α-olefin monomer at each stage of the polymerization process in each Example and Comparative Example are shown in Table 2. Since the monomers were not added in portions in Comparative Examples 5 and 6, the values ​​for Comparative Examples 5 and 6 are not shown in Table 2.

[0132] <Evaluation> In each example, the monomer reaction rate, molecular weight, glass transition temperature, toughness, and polymerization efficiency of the resulting copolymer were measured by the following methods. The measurement results are shown in Tables 2 and 3.

[0133] The method for measuring the glass transition temperature from the results of viscoelastic behavior observation is as follows. In the temperature range of 150°C or higher and 300°C or lower, the glass transition temperature was determined as the peak-top temperature of the tan δ chart obtained by measurement. In the temperature range of 0°C or higher and lower than 150°C, the point at which the value in the chart obtained by differentiating the loss modulus value obtained by measurement with respect to temperature changes from positive to negative with increasing temperature, i.e., the maximum point of the loss modulus, was considered to be the peak, and the temperature at which this peak occurred was determined to be the glass transition temperature. In addition, in this example, if the chart obtained by differentiating the loss modulus value with respect to temperature in the temperature range of 0°C or higher and lower than 150°C does not have a point at which the value changes from positive to negative with increasing temperature, i.e., if the loss modulus chart does not substantially have a maximum point, it was determined that there was no glass transition temperature in that temperature range. However, measurements were performed in the range of -100 to 350°C, and Table 3 lists the glass transition temperatures obtained in the range of 0 to 300°C.

[0134] The films used as samples in measuring the glass transition temperature and evaluating the toughness were prepared by the following method. A mold with a depth of 50 μm was prepared using "Kapton (registered trademark) film" (size: length 100 mm x width 100 mm x thickness 50 μm). Next, the mold was filled with a cyclic olefin copolymer, and then the cyclic olefin copolymer was vacuum-pressed using a thermal vacuum press under conditions of a pressure of 15 MPa, a temperature of 320 to 340°C, and a time of 15 minutes. After pressing, the pressed cyclic olefin copolymer was rapidly cooled by sandwiching it between metal plates at room temperature. After cooling, the metal plates were removed, and a cyclic olefin copolymer film with a thickness of approximately 50 μm was obtained.

[0135] <Monomer Reaction Rate> Using a sample taken directly from the polymerization vessel (Schlenk flask) in dry glassware, the amount of residual monomer was measured using a headspace gas chromatograph (HS-GC) equipped with a flame ionization detector (FID). The monomer reaction rate was calculated based on the measured amount of residual monomer. The measurement conditions were as follows. (HS-GC Measurement) Apparatus: SHIMADZU GC-2010 Plus Oven temperature: 180°C Needle temperature: 200°C Transfer temperature: 200°C HS carrier gas pressure: 190 kPa HS-SPL temperature: 250°C HS-SPL pressure: 155.8 kPa Flow rate: 11.4 ml / min Purge flow rate: 3.0 ml / min Column temperature: 50°C

[0136] <Molecular Weight> The number average molecular weight (Mn) and weight average molecular weight (Mw) were measured by gel permeation chromatography under the following measurement conditions: Apparatus: Viscotek TDA302 detector + Pump autosampler manufactured by Malvern, Detector: RI, Solvent: Toluene, Column: TSKgel GMHHR-M (300 mm x 7.8 mmφ) manufactured by Tosoh Corporation, Flow rate: 1 mL / min, Temperature: 75°C, Sample concentration: 2.5 mg / mL, Injection volume: 100 μL, Standard sample: Monodisperse polystyrene

[0137] <Glass transition temperature> Using the film (thickness: 50 μm) produced by the above method, the glass transition temperature was measured by observing the viscoelastic behavior with a solid rheometer at temperatures from −100° C. to 300° C. Specifically, the peak top temperature in the tan δ chart obtained by the above measurement was taken as the glass transition temperature.

[0138] <Toughness> A folding endurance test (MIT test) in accordance with JIS P 8115 was conducted to evaluate the toughness of each copolymer. Specifically, first, a test piece of a predetermined size (100 mm length x 15 mm width x 50 μm thickness) was cut out from the film prepared by the above-mentioned method. Using the obtained test piece, an MIT test was conducted using an MIT folding endurance fatigue tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the number of times the film could be bent until it broke (folding endurance number) was measured. A higher number of folding endurance numbers means higher toughness of the film. The detailed conditions of the MIT test are as follows: Loading method: Spring load Load: 1 kgf Bending angle: 135° Bending speed: 175 cpm

[0139] <Polymerization Efficiency> The polymerization efficiency was calculated from the amount of catalyst used and the amount of copolymer obtained. The polymerization efficiency is the copolymer yield (g) per 1 g of catalyst.

[0140]

[0141]

[0142]

[0143] Tables 1 and 3 show that when a cyclic olefin copolymer having units derived from a cyclic olefin monomer and units derived from an α-olefin having 3 to 20 carbon atoms is produced by the method of the Examples corresponding to the above-mentioned specified method, a cyclic olefin copolymer having excellent toughness can be efficiently produced. On the other hand, in Comparative Examples 1 and 2 in which the reaction rate of the monomer in the first polymerization was low, and in Comparative Examples 3 to 6 in which the above-mentioned specified first polymerization and second polymerization were not carried out in combination, it was not possible to achieve both the toughness of the resulting cyclic olefin copolymer and good production efficiency of the cyclic olefin copolymer.

Claims

1. A method for producing a cyclic olefin copolymer having units derived from a cyclic olefin monomer and units derived from an α-olefin monomer having 3 to 20 carbon atoms, the method comprising: a first polymerization in which monomers including the cyclic olefin monomer and the α-olefin monomer are polymerized in a polymerization vessel in the presence of a titanocene catalyst, an alkylaluminum compound, and a borate compound; adding the alkylaluminum compound alone to the polymerization vessel after the first polymerization; and a second polymerization in which, after the addition of the alkylaluminum compound, additional monomers are added to the polymerization vessel and the monomers are subsequently polymerized, wherein in the first polymerization, polymerization of the monomers is carried out until the reaction rate of the cyclic olefin monomer is 80 mol % or more relative to the total number of moles of the cyclic olefin monomer added to the polymerization vessel at the start of and during the first polymerization, and the reaction rate of the α-olefin monomer is 80 mol % or more relative to the total number of moles of the α-olefin monomer added to the polymerization vessel at the start of and during the first polymerization.

2. The method for producing a cyclic olefin copolymer according to claim 1, wherein the polymerization reaction is terminated after the second polymerization is carried out.

3. The method for producing a cyclic olefin copolymer according to claim 1, wherein, after a first round of the second polymerization, the addition of the alkyl aluminum compound and the second polymerization are repeated until the alkyl aluminum compound has been added an nth time, wherein n is an integer of 2 or greater, and the pth addition of the alkyl aluminum compound among the 2nd to nth additions is carried out after the (p-1)th round of the second polymerization, the reaction rate of the cyclic olefin monomer has reached 80 mol % or more relative to the sum of the number of moles of the cyclic olefin monomer in the polymerization vessel at the start of the (p-1)th round of the second polymerization and the number of moles of the cyclic olefin monomer added to the polymerization vessel during the (p-1)th round of the second polymerization, and the reaction rate of the α-olefin monomer has reached 80 mol % or more relative to the sum of the number of moles of the α-olefin monomer in the polymerization vessel at the start of the (p-1)th round of the second polymerization and the number of moles of the α-olefin monomer added to the polymerization vessel during the (p-1)th round of the second polymerization, and wherein p is an integer of 2 or greater and n or less, and the polymerization reaction is terminated after the nth round of the second polymerization.

4. The method for producing a cyclic olefin copolymer according to claim 2, wherein in the first polymerization and / or the second polymerization, the monomer is added to the polymerization vessel in two or more divided portions.

5. The method for producing a cyclic olefin copolymer according to claim 4, wherein in the first polymerization and / or the second polymerization, the monomer is added to the polymerization vessel in two separate batches.

6. The method for producing a cyclic olefin copolymer according to claim 5, wherein in the first polymerization and the second polymerization, the monomer is added to the polymerization vessel in two separate batches.

7. The method for producing a cyclic olefin copolymer according to claim 3, wherein in the first polymerization and / or at least one of the n second polymerizations, the monomer is added in two or more portions to the polymerization vessel.

8. The method for producing a cyclic olefin copolymer according to claim 7, wherein in the first polymerization and / or at least one of the n second polymerizations, the monomer is added to the polymerization vessel in two separate batches.

9. The method for producing a cyclic olefin copolymer according to claim 8, wherein in the first polymerization and all of the n number of second polymerizations, the monomer is added to the polymerization vessel in two separate batches.

10. A method for producing a cyclic olefin copolymer according to any one of claims 1 to 9, wherein the alkylaluminum compound used in the first polymerization is a long-chain alkylaluminum compound having only alkyl groups with 6 or more carbon atoms, and the alkylaluminum compound added to the polymerization vessel after the first polymerization is a short-chain alkylaluminum compound having only alkyl groups with 5 or less carbon atoms.

11. The method for producing a cyclic olefin copolymer according to any one of claims 1 to 9, wherein the alkyl aluminum compound is a mixture of alkyl aluminum compound I and alkyl aluminum compound II different from alkyl aluminum compound I, wherein alkyl aluminum compound I has at least one alkyl group having 6 or more carbon atoms, and alkyl aluminum compound II has at least one alkyl group having 5 or less carbon atoms.

12. The method for producing a cyclic olefin copolymer according to claim 10, wherein the alkyl aluminum compound is at least one selected from the group consisting of trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, and tri-n-octylaluminum.

13. The method for producing a cyclic olefin copolymer according to claim 11, wherein the alkyl aluminum compound I is tri-n-octylaluminum, and the alkyl aluminum compound II is trimethylaluminum, triethylaluminum, or triisobutylaluminum.

14. The method for producing a cyclic olefin copolymer according to any one of claims 1 to 9, wherein the amount of the cyclic olefin copolymer obtained is 200 g or more per 1 g of the titanocene catalyst, and the number average molecular weight of the cyclic olefin copolymer obtained is 10,000 to 100,000.

15. The titanocene catalyst is represented by the following formula (1): (In formula (1), R １ ~R ３ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and R ４ and R ５ are each independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom; R ６ ~R １３ and each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a silyl group which may have, as a substituent, a monovalent hydrocarbon group having 1 to 12 carbon atoms.

16. A method for producing a cyclic olefin copolymer according to any one of claims 1 to 9, wherein the cyclic olefin copolymer has two or more glass transition temperatures within the range of 0 to 300°C.