Method for producing cyclic olefin copolymers

Abstract

The present invention provides a method for producing a cyclic olefin copolymer which makes it possible to efficiently produce a cyclic olefin copolymer that is a copolymer of a cyclic olefin monomer and a C3-20 α-olefin, and that has excellent toughness.　A copolymer of a cyclic olefin monomer and a C3-20 α-olefin is produced by a method comprising: a first polymerization in which a cyclic olefin monomer and a monomer including an α-olefin are polymerized in a polymerization container and in the presence of a titanocene catalyst, an alkylaluminum compound, and a borate compound; addition of the monomer and the alkylaluminum compound to the polymerization container after the first polymerization; and a second polymerization in which, after the addition of the monomer and the alkylaluminum compound, polymerization of the monomer is continued.

Description

[Technical Field]

[0001] This invention relates to a method for producing cyclic olefin copolymers. [Background technology]

[0002] Cyclic olefin polymers and cyclic olefin copolymers (also known as "COP" and "COC," respectively) possess low hygroscopicity and high transparency. Therefore, COP and COC are used in a variety of applications, including optical materials such as optical disc substrates, optical films, and optical fibers. A typical COC is a copolymer of cyclic olefin and ethylene. The glass transition temperature (Tg) of such copolymers can be varied by changing the copolymerization composition of the cyclic olefin and ethylene. Therefore, copolymers of cyclic olefin and ethylene can be produced with a higher Tg than COP, and it is possible to achieve Tgs exceeding 200°C, which is difficult with COP. However, such copolymers are hard and brittle. Therefore, these copolymers have problems such as low mechanical strength and poor handling and processability.

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

[0004] Copolymerization of cyclic olefins and specific α-olefins differs significantly from copolymerization of cyclic olefins and ethylene. Under conditions where high molecular weight materials can be obtained through copolymerization of cyclic olefins and ethylene, chain transfer reactions originating from the specific α-olefin occur in copolymerization of cyclic olefins and specific α-olefins, making it difficult to obtain high molecular weight materials until now. Therefore, copolymers of cyclic olefins and specific α-olefins were considered unsuitable for 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 copolymers of cyclic olefins and specific α-olefins that have a relatively high molecular weight and can be molded into films, a method has been proposed in which cyclic olefins and specific α-olefins are copolymerized in the presence of a titanocene catalyst of a specific structure and triphenylmethylium tetrakis(pentafluorophenyl) borate (see Patent Document 1). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2016-56275 [Non-patent literature]

[0007] [Non-Patent Document 1] Jung, HY et al., Polyhedron, 2005, Vol. 24, pp. 1269-1273. [Overview of the Initiative] [Problems that the invention aims to solve]

[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 with excellent toughness.

[0009] The present invention has been made in view of the above circumstances, and aims to provide a method for efficiently producing a cyclic olefin copolymer, which is a copolymer of a cyclic olefin monomer and an α-olefin having 3 to 20 carbon atoms, and which exhibits excellent toughness. [Means for solving the problem]

[0010] The present inventors have found that the above problems can be solved by producing a copolymer of a cyclic olefin monomer and an α-olefin having 3 to 20 carbon atoms in a polymerization vessel by a method comprising: a first polymerization in which a monomer containing the cyclic olefin monomer and the α-olefin is polymerized in the presence of a titanocene catalyst, an alkylaluminum compound, and a borate compound; the addition of the monomer and the alkylaluminum compound to the polymerization vessel after the first polymerization; and a second polymerization in which the monomer is further polymerized after the addition of the monomer and the alkylaluminum compound. Based on this discovery, the present invention has been completed. More specifically, 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 having 3 to 20 carbon atoms, The above manufacturing method, In a polymerization vessel, a first polymerization is carried out in which a monomer containing a cyclic olefin monomer and an α-olefin is polymerized in the presence of a titanocene catalyst, an alkylaluminum compound, and a borate compound. Addition of monomers and alkylaluminum compounds to the polymerization vessel after the first polymerization, The process includes a monomer and an alkylaluminum compound, followed by a second polymerization in which the monomer is further polymerized. In the first polymerization, the monomer polymerization is carried out until the reaction rate of the cyclic olefin monomer reaches 80 mol% or more relative to the number of moles of the cyclic olefin monomer added to the polymerization vessel at the start of the first polymerization. A method for producing a cyclic olefin copolymer, wherein the amount of hindered phenol used in the first polymerization is such that the amount of phenolic hydroxyl groups in the hindered phenol is 1.5 moles or less per mole of alkylaluminum compound.

[0012] (II) A method for producing a cyclic olefin copolymer as described in (I), wherein the polymerization reaction is terminated after the second polymerization is carried out.

[0013] (III) After the first second polymerization, the addition of monomers and alkylaluminum compounds, and the second polymerization, are repeated until the number of additions of monomers and alkylaluminum compounds reaches n. n is an integer greater than or equal to 2, The p-th monomer out of the 2nd to nth regenerations, and alkylaluminum compound The addition is performed in the (p-1)th second polymerization after the reaction rate of the cyclic olefin monomer has reached 80 mol% or more relative to the number of moles of cyclic olefin monomer in the polymerization vessel at the start of the (p-1)th second polymerization. p is an integer between 2 and n. A method for producing a cyclic olefin copolymer as described in (I), wherein the polymerization reaction is terminated after the nth second polymerization.

[0014] (IV) A method for producing a cyclic olefin copolymer according to any one of (I) to (III), 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 fewer carbon atoms.

[0015] (V) From the start of the first polymerization to the end of the second polymerization, both alkylaluminum compound I and alkylaluminum compound II, which is different from alkylaluminum compound I, are used as alkylaluminum compounds. Alkylaluminum compound I has at least one alkyl group with 6 or more carbon atoms, Alkylaluminum compound II is a method for producing a cyclic olefin copolymer according to any one of (I) to (IV), wherein the alkylaluminum compound II has at least one alkyl group having 5 or fewer carbon atoms.

[0016] (VI) Alkyl aluminium compounds include trimethylaluminum, triethylaluminum, triisobutylaluminum, and tri -n-A method for producing the cyclic olefin copolymer according to (IV), wherein the copolymer is at least one selected from the group consisting of octylaluminum.

[0017] (VII) Alkylaluminum compound I is -n- It is octyl aluminum, A method for producing a cyclic olefin copolymer according to (V), wherein alkylaluminum compound II is trimethylaluminum, triethylaluminum, or triisobutylaluminum.

[0018] (VIII) A method for producing a cyclic olefin copolymer according to any one of (I) to (VII), wherein the number-average molecular weight of the resulting cyclic olefin copolymer is 10,000 to 100,000.

[0019] (IX) The titanocene catalyst is given by the following formula (1): [ka] (In formula (1), R 1 ~R 3 Each of these is independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, R 4 and R 5 Each of these is independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, and R 6 ~R 13 Each of these is a silyl group that may independently have a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms or less, or a monovalent hydrocarbon group having 1 to 12 carbon atoms as a substituent. A method for producing a cyclic olefin copolymer according to any one of (I) to (VIII), which is a compound represented by .

[0020] (X) A method for producing a cyclic olefin copolymer according to any one of (I) to (IX), wherein the cyclic olefin copolymer has two or more glass transition temperatures in the range of 0 to 300°C. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a method for efficiently producing a cyclic olefin copolymer, which is a copolymer of a cyclic olefin monomer and an α-olefin having 3 to 20 carbon atoms, and which exhibits excellent toughness. [Modes for carrying out the invention]

[0022] The embodiments of the present invention will be described in detail below. However, the present invention is not limited to the embodiments described below.

[0023] ≪Cyclic olefin copolymer≫ The cyclic olefin copolymer produced by the manufacturing method described later is an addition polymer of a cyclic olefin monomer and an α-olefin having 3 to 20 or fewer carbon atoms.

[0024] The ratio of moles of structural units derived from α-olefins to moles of total structural units in a cyclic olefin copolymer is not particularly limited, but is preferably 10 to 50 mol%, more preferably 20 to 40 mol%, and even more preferably 20 to 30 mol%. When a cyclic olefin copolymer has structural units derived from α-olefins 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 moles of structural units derived from α-olefins is, 13 This can be calculated by measuring the 1C-NMR spectrum.

[0025] The cyclic olefin copolymer may contain structural units other than those derived from cyclic olefin monomers and α-olefins having 3 to 20 carbon atoms, to the extent that they do not hinder the objectives of the present invention. Other structural units may include those derived from compounds copolymerizable with cyclic olefin monomers and α-olefins having 3 to 20 carbon atoms and having carbon-carbon unsaturated double bonds. Typically, structural units derived from ethylene are preferred as other structural units.

[0026] In a cyclic olefin copolymer, the sum of the ratio of moles of structural units derived from cyclic olefin monomers to the total number of moles of structural units derived from α-olefins, to the total number of moles of 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%.

[0027] It is preferable that the cyclic olefin copolymer has two or more glass transition temperatures within the range of 0 to 300°C. The glass transition temperature can be measured by observing the viscoelastic behavior of a 50 μm thick film-like molded product using a solid-state rheometer from -100 to 300°C. Specifically, the temperature at the top of the peak in the tan δ chart obtained from the aforementioned measurement is defined as the glass transition temperature.

[0028] Because the mechanical properties measured by tensile testing are good, it is preferable that the cyclic olefin copolymer has at least one glass transition temperature in the range of 0 to 100°C and at least one in the range of 160 to 300°C. In particular, because the fracture strain measured by tensile testing is large and the toughness is excellent, it is preferable that the cyclic olefin copolymer has at least one glass transition temperature in the range of less than 0°C, in the range of 0 to 100°C, and in 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 range below 0°C mentioned above, -50 to 0°C is preferred, and -40 to -10°C is more preferred.

[0029] Typically, it is preferable that the cyclic olefin copolymer has one glass transition temperature each in the range of 0 to 100°C and the range of 160 to 300°C, or one glass transition temperature each in the range of less than 0°C, the range of 0 to 100°C, and the range of 160 to 300°C.

[0030] The molecular weight of the cyclic olefin copolymer is not particularly limited. The weight-average molecular weight (Mw) of the cyclic olefin copolymer is preferably 5,000 to 200,000, and more preferably 10,000 to 100,000, as measured by gel permeation chromatography (GPC) in terms of polystyrene. The number-average molecular weight (Mn) of the cyclic olefin copolymer is preferably 5,000 to 200,000, and more preferably 10,000 to 100,000, as measured by gel permeation chromatography (GPC) in terms of polystyrene equivalent. Because cyclic olefin copolymers exhibit excellent toughness, it is preferable that the dispersion ratio (Mw / Mn) is not excessively high. Specifically, the dispersion ratio (Mw / Mn) is preferably 1.75 or less, more preferably 1.70 or less, and even more preferably 1.60 or less. The lower limit of the variance ratio (Mw / Mn) is not particularly limited. The variance ratio (Mw / Mn) may be, for example, 1.1 or greater.

[0031] <Cyclic Olefin Monomers> The cyclic olefin monomer is not particularly limited as long as it does not hinder the objectives of the present invention. Typically, norbornene and substituted norbornene are preferably used as cyclic olefin monomers. Among the cyclic olefin monomers, norbornene is particularly preferred due to its good balance of cost, polymerizability, and the physical properties of the resulting cyclic olefin copolymer. The cyclic olefin monomers can be used individually or in combination of two or more.

[0032] The substituted norbornene is not particularly limited. Examples of the substituent that the substituted norbornene has include a halogen atom and a monovalent or divalent hydrocarbon group. Specific examples of the substituted norbornene include the compound represented by the following formula (I).

[0033]

Chemical formula

[0034] In formula (I), R a1 ~R a12 may be the same or different from each other, and is an atom or group selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group. R a9 and R a10 , R a11 and R a12 may integrally form a divalent hydrocarbon group. R 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 from each other in each repeating unit. However, when n is 0, at least one of R a1 ~R a4 and R a9 ~R a12 is not a hydrogen atom.

[0035] Examples of R a1 ~R a8 include, for example, a hydrogen atom; a halogen atom such as fluorine, chlorine, and bromine; an alkyl group having 1 to 20 carbon atoms, and the like. R a1 ~R a8 may all consist of different atoms or groups. Part or all of R a1 ~R a8 may be the same atom or group.

[0036] R a9 ~R a12 Specific examples include, for instance, hydrogen atoms; halogen atoms such as fluorine, chlorine, and bromine; alkyl groups having 1 to 20 carbon atoms; cycloalkyl groups such as cyclohexyl groups; substituted or unsubstituted aromatic hydrocarbon groups such as phenyl, tolyl, ethylphenyl, isopropylphenyl, naphthyl, and anthryl groups; and aralkyl groups such as benzyl and phenethyl groups. a9 ~R a12 It may consist entirely of different atoms or groups. a9 ~R a12 Some or all of these may be the same atom or group.

[0037] R a9 and R a10 , or R a11 and R a12 Specific examples of divalent hydrocarbon groups that can be formed by the integration of these include alkylidene groups such as ethylidene, propyridene, and isopropylidene.

[0038] R a9 or R a10 And, R a11 or R a12 When these elements bond to each other to form a ring, the formed ring may be monocyclic or polycyclic. The formed ring may be polycyclic with bridges. The formed ring may have double bonds. The formed ring may have substituents such as methyl groups.

[0039] Specific examples of substituted norbornenes represented by formula (I) include 5-methyl-bicyclo[2.2.1]hepta-2-ene, 5,5-dimethyl-bicyclo[2.2.1]hepta-2-ene, 5-ethyl-bicyclo[2.2.1]hepta-2-ene, 5-butyl-bicyclo[2.2.1]hepta-2-ene, 5-ethylidene-bicyclo[2.2.1]hepta-2-ene, and 5-hexyl-bi Bicyclic olefins such as cyclo[2.2.1]hepta-2-ene, 5-octyl-bicyclo[2.2.1]hepta-2-ene, 5-octadecyl-bicyclo[2.2.1]hepta-2-ene, 5-methylidene-bicyclo[2.2.1]hepta-2-ene, 5-vinyl-bicyclo[2.2.1]hepta-2-ene, and 5-propenyl-bicyclo[2.2.1]hepta-2-ene; Tricyclo[4.3.0.1 2,5 Deca-3,7-diene (common name: dicyclopentadiene), tricyclo[4.3.0.1 2,5 Deca-3-en; Tricyclo[4.4.0.1 2,5 ]Undeca-3,7-diene or tricyclo[4.4.0.1 2,5 ] Tricyclo[4.4.0.1 2,5 ]undeca-3-ene; 5-cyclopentyl-bicyclo[2.2.1]hepta-2-ene, 5-cyclohexyl-bicyclo[2.2.1]hepta-2-ene, 5-cyclohexenylbicyclo[2.2.1]hepta-2-ene, 5-phenyl-bicyclo[2.2.1]hepta-2-ene, and other tricyclic olefins; Tetracyclo[4.4.0.1 2,5 .1 7,10 ] Dodeca-3-ene (also simply called tetracyclododecene), 8-methyltetracyclo[4.4.0.1 2,5 .1 7,10 ] Dodeca-3-ene, 8-ethyltetracyclo[4.4.0.1 2,5 .1 7,10 ] Dodeca-3-ene, 8-methylidenetetracyclo[4.4.0.1 2,5 .1 7,10Dodeca-3-ene, 8-ethylidene-tetracyclo[4.4.0.1 2,5 .1 7,10 Dodeca-3-ene, 8-vinyl-tetracyclo[4,4.0.1 2,5 .1 7,10 Dodeca-3-ene, 8-prophenyl-tetracyclo[4.4.0.1 2,5 .1 7,10 4-ring cyclic olefins such as dodeca-3-ene; 8-cyclopentyl-tetracyclo[4.4.0.1 2,5 .1 7,10 Dodeca-3-ene, 8-cyclohexyl-tetracyclo[4.4.0.1 2,5 .1 7,10 Dodeca-3-ene, 8-cyclohexenyl-tetracyclo[4.4.0.1 2,5 .1 7,10 Dodeca-3-ene, 8-phenyl-cyclopentyl-tetracyclo[4.4.0.1 2,5 .1 7,10 Dodeca-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 called 1,4-methano-4,4a,5,10,10a-hexahydroanthracene); Pentacyclo[6.6.1.1 3,6 .0 2,7 .0 9,14 -4-hexadecene, Pentacyclo[6.5.1.1 3,6 .0 2,7 .0 9,13 -4-pentadecene, Pentacyclo[7.4.0.0 2,7 .1 3,6 .1 10,13 -4-pentadecene; Heptacyclo[8.7.0.1 2,9 .1 4,7 .1 11,17 .0 3,8 .0 12,16]-5-eicosene, heptacyclo[8.7.0.1 2,9 .0 3,8 .1 4,7 .0 12,17 .1 13,l6 Examples include polycyclic cyclic olefins such as tetramers of ]-14-eicosene and cyclopentadiene.

[0040] Among these, alkyl-substituted norbornenes such as bicyclo[2.2.1]hepta-2-ene substituted with one or more alkyl groups, and alkylidene-substituted norbornenes such as bicyclo[2.2.1]hepta-2-ene substituted with one or more alkylidene groups are preferred. 5-Ethylidene-bicyclo[2.2.1]hepta-2-ene (common name: 5-ethylidene-2-norbornene, or simply ethylidene norbornene) is particularly preferred.

[0041] <α-olefin> Alpha-olefins are alpha-olefins with 3 to 20 carbon atoms. As such α-olefins, not only unsubstituted α-olefins but also substituted α-olefins having substituents such as halogen atoms can be used. The number of carbon atoms in the α-olefin is 3 to 20, preferably 4 to 12, and more preferably 6 to 10.

[0042] Specific examples of α-olefins 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.

[0043] The above-mentioned cyclic olefin copolymer can be mixed with various additives as needed, and then molded into films, sheets, etc., for use in a wide range of applications such as packaging and optical applications. Additives that can be added to the cyclic olefin copolymer include antioxidants, weather stabilizers, UV absorbers, antibacterial agents, flame retardants, and colorants. These additives are added to the cyclic olefin copolymer in amounts that take into account the typical usage amounts for each type of additive.

[0044] ≪Method for producing cyclic olefin copolymers≫ The following describes a method for producing cyclic olefin copolymers.

[0045] The method for producing cyclic olefin copolymers described below produces cyclic olefin copolymers having units derived from cyclic olefin monomers and units derived from α-olefins with 3 to 20 carbon atoms. The cyclic olefin copolymer is as described above.

[0046] The above manufacturing method is In a polymerization vessel, a first polymerization is carried out in which a monomer containing a cyclic olefin monomer and an α-olefin is polymerized in the presence of a titanocene catalyst, an alkylaluminum compound, and a borate compound. Addition of monomers and alkylaluminum compounds to the polymerization vessel after the first polymerization, The process includes a monomer and an alkylaluminum compound, followed by a second polymerization in which the monomer is further polymerized. In the first polymerization, the reaction rate of the cyclic olefin monomer is determined by the start of the first polymerization. Sometimes Cyclic olefin monomer added to polymerization vessel no mo Polymerization of monomers continues until the monomer content reaches 80 mol or more relative to the number of units.

[0047] By the above method, a cyclic olefin copolymer with excellent toughness, which is a copolymer of a cyclic olefin monomer and an α-olefin having 3 to 20 carbon atoms, can be efficiently produced. Specifically, the amount of cyclic olefin copolymer obtained can be 200 g or more per gram of titanocene catalyst.

[0048] The following describes the first polymerization, the addition of monomers and alkylaluminum compounds, and the second polymerization.

[0049] <First polymerization> In the first polymerization, a cyclic olefin monomer and a monomer containing an α-olefin are polymerized in a polymerization vessel in the presence of a titanocene catalyst, an alkylaluminum compound, and a borate compound. In the first polymerization, the reaction rate of the cyclic olefin monomer is determined by the start of the first polymerization. Sometimes Cyclic olefin monomer added to polymerization vessel no mo Polymerization of monomers continues until the monomer content reaches 80 mol or more relative to the number of units. In this case, it is easy to obtain a cyclic olefin copolymer with excellent toughness, having at least one glass transition temperature in the range below 0°C, in the range of 0 to 100°C, and in the range of 160 to 300°C.

[0050] The cyclic olefin monomers and monomers containing α-olefins are as described above. As will be described later, when producing a cyclic olefin copolymer, monomers are added to the polymerization vessel both at the start of the first polymerization and after the first polymerization. In the first polymerization, the total amount of monomer added to the polymerization vessel is preferably 20 to 80 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%, relative to the total number of moles of monomer used in the production of the cyclic olefin copolymer.

[0051] [Titanocene catalyst] The titanocene catalyst is not particularly limited as long as it is a titanocene catalyst capable of copolymerizing a cyclic olefin monomer with an α-olefin having 3 to 20 carbon atoms. Typically, the titanocene catalyst is appropriately selected from known titanocene catalysts capable of copolymerizing a cyclic olefin monomer with an α-olefin having 3 to 20 carbon atoms. As the titanocene catalyst, one kind may be used alone or two or more kinds may be used in combination.

[0052] Preferred titanocene catalysts include titanocene catalysts represented by the following formula (1).

Chemical formula

[0053] 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 methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, cyclopentyl group, cyclohexyl group; phenyl group, biphenyl group, phenyl group or biphenyl group having the above alkyl group as a substituent, naphthyl group, naphthyl group having the above alkyl group as a substituent, and other aryl groups.

[0054] R 4 and R 5Each of these is independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom. Specifically, examples include halogen atoms such as fluorine, chlorine, bromine, and iodine; methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, heptyl, octyl, cyclopentyl, and cyclohexyl groups, and these alkyl groups having the above halogen atoms as substituents; and phenyl, biphenyl, and naphthyl groups, and these aryl groups having the above halogen atoms or alkyl groups as substituents.

[0055] R 6 ~R 13 Each of these is independently a silyl group which may have a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a monovalent hydrocarbon group having 1 to 12 carbon atoms as a substituent. Specific examples of alkyl groups having 1 to 12 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, heptyl, octyl, cyclopentyl, and cyclohexyl groups. Specific examples of aryl groups having 6 to 12 carbon atoms include phenyl, biphenyl, naphthyl, and these aryl groups having the above alkyl groups as substituents. Furthermore, specific examples of silyl groups having a monovalent hydrocarbon group with 1 to 12 carbon atoms as a substituent include silyl groups having alkyl groups with 1 to 12 carbon atoms as substituents, such as 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.

[0056] Specific examples of titanocene catalysts represented by general formula (1) include (isopropylamide)dimethyl-9-fluorenylsilanthandimethyl, (isobutylamide)dimethyl-9-fluorenylsilanthandimethyl, (t-butylamide)dimethyl-9-fluorenylsilanthandimethyl, (isopropylamide)dimethyl-9-fluorenylsilanthan dichloride, (isobutylamide)dimethyl-9-(3,6-dimethylfluorenyl)silanthan dichloride, (t-butylamide)dimethyl-9-fluorenylsilanthan dichloride, ( (Isopropylamide)dimethyl-9-(3,6-dimethylfluorenyl)silantitane dichloride, (Isobutylamide)dimethyl-9-(3,6-dimethylfluorenyl)silantitane dichloride, (t-Butylamide)dimethyl-9-(3,6-dimethylfluorenyl)silantitane dimethyl, (Isopropylamide)dimethyl-9-[3,6-di(i-propyl)fluorenyl]silantitane dichloride, (Isobutylamide)dimethyl-9-[3,6-di(i-propyl)fluorenyl]silantitane dichloride, (t-Butylamide)dimethyl Dimethyl-9-[3,6-di(i-propyl)fluorenyl]silantitane dimethyl, (isopropylamide)dimethyl-9-[3,6-di(t-butyl)fluorenyl]silantitane dichloride, (isobutylamide)dimethyl-9-[3,6-di(t-butyl)fluorenyl]silantitane dichloride, (t-butylamide)dimethyl-9-[3,6-di(t-butyl)fluorenyl]silantitane dimethyl, (isopropylamide)dimethyl-9-[2,7-di(t-butyl)fluorenyl]silantitane dichloride, (isobutylamide)dimeth Examples include ru-9-[2,7-di(t-butyl)fluorenyl]silantitane dichloride, (t-butylamide)dimethyl-9-[2,7-di(t-butyl)fluorenyl]silantitane dimethyl, (isopropylamide)dimethyl-9-(2,3,6,7-tetramethylfluorenyl)silantitane dichloride, (isobutylamide)dimethyl-9-(2,3,6,7-tetramethylfluorenyl)silantitane dichloride, and (t-butylamide)dimethyl-9-(2,3,6,7-tetramethylfluorenyl)silantitane dimethyl.Preferably, it is (t-butylamide)dimethyl-9-fluorenylsilanthandimethyl ((t-BuNSiMe2Flu)TiMe2). (t-BuNSiMe2Flu)TiMe2 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".

[0057] [ka] (In the formula, Me represents a methyl group, and t-Bu represents a tert-butyl group.)

[0058] The amount of titanocene catalyst used is not particularly limited as long as the addition polymerization reaction proceeds smoothly. The amount of 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 cyclic olefin monomer and α-olefin.

[0059] The titanocene catalyst may be added to the polymerization vessel after the start of the first polymerization, in addition to at the start of the first polymerization. However, it is preferable that the entire amount of titanocene catalyst used in the production of the cyclic olefin copolymer is charged into the polymerization vessel at the start of the first polymerization.

[0060] [Alkylaluminum compounds] The first polymerization is carried out in the presence of a titanocene catalyst, an alkylaluminum compound, and a borate compound. In the first polymerization stage, the alkylaluminum compound introduced into the polymerization vessel at the start of polymerization acts as a scavenger, capturing water, oxygen, and other impurities.

[0061] In the first polymerization, the alkylaluminum compound that is placed in 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 limitations. In the first polymerization, one alkylaluminum compound may be used alone, or two or more may be used in combination.

[0062] In the first polymerization, preferred examples of alkylaluminum compounds to be placed in the polymerization vessel at the start of polymerization include trialkylaluminum, dialkylaluminum halide, dialkylaluminum hydride, and dialkylaluminum alkoxide. Among these, trialkylaluminum is preferred.

[0063] Suitable examples of trialkylaluminum include trimethylaluminum, triethylaluminum, triisopropylaluminum, and tri - n-butylaluminum, triisobutylaluminum, tri - sec-butylaluminum, and tri - Examples include n-octyl aluminum. Among these, triisobutylaluminum and tri -n- Octyl aluminum is preferred.

[0064] Suitable examples of dialkylaluminum halides include dimethylaluminum chloride and diisobutylaluminum chloride.

[0065] Preferred specific examples of dialkylaluminum hydrides include diisobutylaluminum hydride.

[0066] A suitable example of a dialkylaluminum alkoxide is dimethylaluminum methoxide.

[0067] In the first polymerization, the alkylaluminum compound placed in the polymerization vessel at the start of polymerization is preferably a long-chain alkylaluminum compound having only alkyl groups with 6 or more carbon atoms. Long-chain alkylaluminum compounds act well as scavengers.

[0068] The amount of alkylaluminum compound used in the first polymerization is preferably 0.1 to 200 parts by mass, more preferably 1 to 100 parts by mass, and even more preferably 10 to 50 parts by mass, based on 100 parts by mass of the total amount of titanocene catalyst used in the production of the cyclic olefin copolymer.

[0069] [Borate compounds] 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 cyclic olefin monomers can be used without particular limitation. In the first polymerization, one borate compound may be used alone, or two or more may be used in combination.

[0070] Preferred examples of borate compounds include triphenylmethylium tetrakis(pentafluorophenyl) borate, dimethylphenylammonium tetrakis(pentafluorophenyl) borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl) borate, and N-methyldinormaldecylammonium tetrakis(pentafluorophenyl) borate.

[0071] The amount of borate compound used in the first polymerization is not particularly limited, as long as the addition polymerization reaction proceeds well and a cyclic olefin copolymer with the desired properties is obtained. The amount of borate compound used is preferably 250 to 750 parts by mass, and more preferably 300 to 500 parts by mass, per 100 parts by mass of the total amount of titanocene catalyst used in the production of the cyclic olefin copolymer.

[0072] The borate compound may be added to the polymerization vessel after the start of the first polymerization, in addition to at the start of the first polymerization. However, it is preferable that the entire amount of the borate compound used in the production of the cyclic olefin copolymer is added to the polymerization vessel at the start of the first polymerization.

[0073] [Other ingredients] In the first polymerization, the polymerization of the monomers described above may be carried out in the presence of other components other than the alkylaluminum compound and the borate compound, to the extent that it does not hinder the objective of the present invention. Other suitable examples of components include hindered phenols. The hindered phenol can be any hindered phenol that has been conventionally used as a co-catalyst in the homopolymerization or copolymerization of cyclic olefin monomers, without any particular limitations. ru . Here, hindered phenols are phenols having a bulky substituent on at least one of the two adjacent positions of a phenolic hydroxyl group. Examples of bulky substituents include isopropyl, isobutyl, sec-butyl, and tert-butyl groups. basis Examples include alkyl groups other than methyl groups, alkenyl groups, alkynyl groups, aryl groups, heterocyclic groups, alkoxy groups, aryloxy groups, substituted amino groups, alkylthio groups, and arylthio groups.

[0074] Specific examples of hindered phenols include, for example, 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, 3,3',5,5'-tetra-tert-butyl-2,2'-dihydroxybiphenyl, 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 2,2'-methylenebis(6-tert-butyl-4-methylphenol), 4,4',4”-(1-methylpropanyl-3-ylidene)tris(6-tert-butyl-m-cresol), and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylmethyl)2,4,6-trimethylbenzene. Among these, 2,6-di-tert-butyl-4-hydroxytoluene (BHT) and 2,6-di-tert-butylphenol are preferred because they have a small molecular weight and make it easy to obtain the desired effect of using hindered phenols with small amounts.

[0075] The amount of hindered phenol used in the first polymerization is not particularly limited, as long as the addition polymerization reaction proceeds well and a cyclic olefin copolymer with the desired properties is obtained. The amount of hindered phenol used is preferably 1 to 1000 parts by mass, more preferably 10 to 500 parts by mass, and even more preferably 100 to 200 parts by mass, based on 100 parts by mass of the total amount of titanocene catalyst used in the production of the cyclic olefin copolymer. However, the amount of hindered phenol used is such that the amount of phenolic hydroxyl groups in the hindered phenol is 1.5 moles or less per mole of alkylaluminum compound. The amount of phenolic hydroxyl groups in the hindered phenol per mole of alkylaluminum compound is preferably 1.4 moles or less, more preferably 1.3 moles or less, and even more preferably 1.2 moles or less. compoundWhen the amount of hindered phenol used is within the above range, the chain transfer reaction of alkylaluminum compounds is less likely to be inhibited.

[0076] <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 they have excellent handling properties, 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.

[0077] The solvent may be placed in the polymerization vessel alone, or it may be placed in the polymerization vessel in the form of a monomer solution, a catalyst solution, or a co-catalyst solution.

[0078] When a solvent is used, the amount used is not particularly limited. The amount of solvent used is preferably 100 to 100,000 parts by mass, more preferably 500 to 10,000 parts by mass, and even more preferably 1,000 to 5,000 parts by mass, per 100 parts by mass of the total amount of monomers used in the first polymerization.

[0079] <Reaction conditions> The polymerization temperature in the first polymerization is not particularly limited. The polymerization temperature is preferably -20 to 200°C, more preferably -10 to 10°C, and even more preferably -5 to 5°C. The duration of the first polymerization is not particularly limited, as long as polymerization proceeds until a predetermined amount of monomer is consumed. In the first polymerization, monomer polymerization is carried out until the reaction rate of the cyclic olefin monomer reaches 80 mol% or more relative to the number of moles of cyclic olefin monomer added to the polymerization vessel at the start of the first polymerization. Typically, the time for the first polymerization is preferably 5 to 30 minutes, more preferably 8 to 20 minutes, and even more preferably 10 to 15 minutes.

[0080] The atmosphere in which the above-described first polymerization reaction takes place is not particularly limited, but an inert gas atmosphere is preferred. Nitrogen gas or helium gas can be used as the inert gas.

[0081] <Addition of monomers and alkylaluminum compounds> After the first polymerization, monomers and alkylaluminum compounds are added to the polymerization vessel. The alkylaluminum compounds added to the polymerization vessel after the first polymerization act as chain transfer agents. By performing the second polymerization, described later, in the presence of the alkylaluminum compounds acting as chain transfer agents, the yield of cyclic olefin copolymers per unit weight of titanocene catalyst can be increased without excessively increasing the dispersion ratio of the molecular weight of the resulting cyclic olefin copolymers. Furthermore, if the monomer and the alkylaluminum compound are added to the polymerization vessel as a mixture after the first polymerization, the alkylaluminum compound is thought to act as a scavenger, capturing water, oxygen, and other impurities from the monomer.

[0082] As the alkylaluminum compound added to the polymerization vessel after the first polymerization, the same compound as the alkylaluminum compound used in the first polymerization can be used. 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 compound added to the polymerization vessel after the first polymerization may be used alone or in combination of two or more compounds.

[0083] Suitable examples of trialkylaluminum added to the polymerization vessel after the first polymerization include trimethylaluminum, triethylaluminum, triisopropylaluminum, and tri - n-butylaluminum, triisobutylaluminum, tri - sec-butylaluminum, and tri - Examples include n-octylaluminum. Among these, trimethylaluminum and triethylaluminum are preferred.

[0084] The alkylaluminum compound added to the polymerization vessel after the first polymerization is preferably a short-chain alkylaluminum compound having only alkyl groups with 5 or fewer carbon atoms. Short-chain alkylaluminum compounds act well as chain transfer agents. Therefore, using short-chain alkylaluminum compounds as the alkylaluminum compounds added to the polymerization vessel after the first polymerization makes it easier to obtain cyclic olefin copolymers with particularly excellent heat resistance and toughness, and also makes it easier to increase the yield of cyclic olefin copolymers per unit weight of titanocene catalyst.

[0085] As described above, the purpose of the alkylaluminum compound added to the polymerization vessel at the start of the first polymerization is different from the purpose of the alkylaluminum compound added to the polymerization vessel after the first polymerization. From the above points, both alkylaluminum compound I and alkylaluminum compound II, which is different from alkylaluminum compound I, are used from the start of the first polymerization to the end of the second polymerization. re It is preferable to do so. Alkylaluminum compound I and alkylaluminum compound II may be added to the polymerization vessel at any point between the start of the first polymerization and the end of the second polymerization. Alkylaluminum compound I has at least one alkyl group having 6 or more carbon atoms. Alkylaluminum compound II has at least one alkyl group having 5 or fewer carbon atoms. For example, alkylaluminum compound I may be added to the polymerization vessel at the start of the first polymerization, and alkylaluminum compound II may be added to the polymerization vessel at some point 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 some point after the first polymerization. Furthermore, at the start of the first polymerization, alkylal Mi The nium compound I and the alkylaluminum compound II may be added to the polymerization vessel simultaneously, or a mixture of the alkylaluminum compound I and the alkylaluminum compound II may be added to the polymerization vessel. In this case, any alkylaluminum compound can be added to the polymerization vessel at any time after the first polymerization, and it is preferable to add the alkylaluminum compound II to the polymerization vessel at any time after the first polymerization.

[0086] Alkylaluminum 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. Alkylaluminum compound II preferably has two or three alkyl groups having 5 or fewer carbon atoms, and more preferably has three alkyl groups having 5 or fewer carbon atoms. Alkylaluminum compound I and alkylaluminum compound II may be dialkylaluminum halide, dialkylaluminum hydride, or dialkylaluminum alkoxide, respectively.

[0087] In the first polymerization and the second polymerization, if two alkylaluminum compounds are used as alkylaluminum compounds, one having an alkyl group with 6 or more carbon atoms and the other having an alkyl group with 5 or fewer carbon atoms, either alkylaluminum compound may be alkylaluminum compound I, or either alkylaluminum compound may be alkylaluminum compound II.

[0088] In the first polymerization and the second polymerization, when both alkylaluminum compound I and alkylaluminum compound II are used as alkylaluminum compounds, the ratio of alkylaluminum compound I to alkylaluminum compound II is preferably 2:8 to 8:2 as a molar ratio, more preferably 3:7 to 7:3, and even more preferably 4:6 to 6:4.

[0089] As will be explained in more detail later, the addition of monomers and alkylaluminum compounds after the first polymerization and the second polymerization may be repeated. In other words, monomers and alkylaluminum compounds may be added to the polymerization vessel multiple times after the first polymerization.

[0090] After the first polymerization, the total amount of alkylaluminum compound added to the polymerization vessel is preferably 0.1 to 200 parts by mass, more preferably 1 to 100 parts by mass, and even more preferably 10 to 50 parts by mass, based on 100 parts by mass of the total amount of titanocene catalyst used in the production of the cyclic olefin copolymer. If alkylaluminum compounds are added multiple times after the first polymerization, the amount of alkylaluminum compound added each time 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 alkylaluminum compounds added after the first polymerization and N is the number of divisions.

[0091] After the first polymerization, monomers are added to the polymerization vessel along with the alkylaluminum compound. The composition of the monomers added to the polymerization vessel after the first polymerization may be the same as or different from the composition of the monomers in the first polymerization, but it is preferable that they be the same. After the first polymerization, only cyclic olefin monomers or only α-olefins may be added as monomers, but it is preferable to add monomers containing both cyclic olefin monomers and α-olefins.

[0092] As mentioned above, monomers may be added to the polymerization vessel multiple times after the first polymerization.

[0093] After the first polymerization, the total amount of monomers added to the polymerization vessel is preferably 20 to 80 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%, relative to the total number of moles of monomers used in the production of the cyclic olefin copolymer.

[0094] If monomers are added multiple times after the first polymerization, the amount of monomer added each time 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 monomers added after the first polymerization and N is the number of divisions.

[0095] <Second polymerization> After the first polymerization, monomers and alkylaluminum compounds are added to the polymerization vessel, and then a second polymerization is carried out in which the monomers are further polymerized. In the second polymerization, the composition of the monomer added to the polymerization vessel may be the same as or different from the composition of the monomer in the first polymerization, but it is preferable that it be the same. In the second polymerization, only cyclic olefin monomers or only α-olefins may be added as monomers, but it is preferable to add monomers containing both cyclic olefin monomers and α-olefins.

[0096] As will be explained in more detail later, the addition of the alkylaluminum compound after the first polymerization and the second polymerization may be repeated. In other words, the second polymerization may be performed multiple times after the first polymerization.

[0097] Regarding the reaction conditions for the second polymerization, the reaction temperature is the same as for the first polymerization. The reaction time is not particularly limited. The second polymerization should be continued until the desired amount of cyclic olefin copolymer having the desired physical properties is produced. Typically, the time for the second polymerization is preferably, for example, 5 to 300 minutes, more preferably 8 to 120 minutes, and even more preferably 10 to 60 minutes. If the second polymerization is repeated multiple times, the polymerization time for the second polymerization is the sum of the polymerization times for all multiple second polymerization steps. When the second polymerization is repeated multiple times, the polymerization time for each of the multiple second polymerization steps is not particularly limited. When multiple second polymerizations are performed 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 even more preferably TT / N × 0.9 to TT / N × 1.1, where TT / N × 0.7 to TT / N × 1.3 is the total time for multiple second polymerizations and N is the number of times the second polymerization is performed.

[0098] In the method described above, the polymerization reaction may be terminated after the first polymerization, the addition of the monomer and alkylaluminum compound, and the second polymerization. In this case, the number of steps is reduced, and the production of cyclic olefin copolymers is facilitated.

[0099] When the second polymerization is performed only once, the reaction rate of the cyclic olefin monomer in the second polymerization is not particularly limited, but it is preferably 80 mol% or more relative to the number of moles of cyclic olefin monomer in the polymerization vessel at the start of the second polymerization. In this case, it is easy to obtain a cyclic olefin copolymer with excellent toughness, having at least one glass transition temperature in the range below 0°C, in the range of 0 to 100°C, and in the range of 160 to 300°C. The number of moles of cyclic olefin monomer in the polymerization vessel at the start of the second polymerization is the sum of the number of moles of cyclic olefin monomer remaining in the polymerization vessel after the first polymerization and the number of moles of cyclic olefin monomer added to the polymerization vessel after the first polymerization.

[0100] Furthermore, after the first second polymerization, the addition of the monomer and alkylaluminum compound, followed by the second polymerization, may be repeated until the number of additions of the monomer and alkylaluminum compound reaches n. The monomer and alkylaluminum compound are added in the p-th polymerization out of the 2nd to nth polymerizations. compound The addition of is performed after the (p-1)th second polymerization, where n is an integer greater than or equal to 2. p-th monomer and alkylaluminum compound The addition is performed in the (p-1)th second polymerization after the reaction rate of the cyclic olefin monomer has reached 80 mol% or more relative to the number of moles of cyclic olefin monomer in the polymerization vessel at the start of the (p-1)th second polymerization. In this case, it is easy to obtain a cyclic olefin copolymer with excellent toughness, having at least one glass transition temperature in the range below 0°C, in the range of 0 to 100°C, and in the range of 160 to 300°C. The number of moles of cyclic 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 remaining in the polymerization vessel at the end of the (p-2)th second polymerization and the number of moles of cyclic olefin monomer added to the polymerization vessel immediately before the start of the (p-1)th second polymerization. In this method, the polymerization reaction is terminated after the nth second polymerization step.

[0101] In the method for producing cyclic olefin copolymers described above, it is preferable that the amount of cyclic olefin copolymer obtained is 200 g or more per 1 g of titanocene catalyst, and that the number-average molecular weight of the obtained cyclic olefin copolymer is 10,000 to 100,000. [Examples]

[0102] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0103] In the following examples and comparative examples, a titanocene catalyst with the following structure was used. In the following formula, Me is a methyl group and t-Bu is a tert-butyl group. [ka]

[0104] [Example 1] (First polymerization) In Example 1, 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 17.28 mmol. In a 50 mL Schlenk flask, under a nitrogen atmosphere, 2-norbornene, 1 / 4 of 1-octene, and 0.016 mmol of trimethylaluminum were added. The contents of the flask were then diluted with decalin to a volume of 21.9 mL. Next, the contents of the flask were cooled to 0°C. After cooling, a toluene solution of titanocene catalyst at a concentration of 0.16 mmol / mL was added to the reaction mixture to arrive at a total titanocene catalyst amount of 0.016 mmol. Then, a toluene solution of borate compound at a concentration of 0.008 mmol / L was added to the reaction mixture to arrive at a total borate compound amount of 0.016 mmol. Triphenylmethylium tetrakis(pentafluorophenyl)borate was used as the borate compound. After initiating addition polymerization by adding the titanocene catalyst and borate compound, the reaction was carried out at 0°C for 10 minutes while stirring the reaction mixture with a magnetic stirrer. The reaction rate of 2-norbornene was 87 mol% relative to the number of moles of 2-norbornene at the start of polymerization.

[0105] (Addition of monomer and alkylaluminum compound in the first step) After 10 minutes of reaction, 2-norbornene, 1 / 4 of 1-octene, and 0.016 mmol of trimethylaluminum were added to the Schlenk flask.

[0106] (First polymerization) The addition polymerization reaction was then continued for 10 minutes. The reaction rate of 2-norbornene after a 10-minute reaction in the second polymerization was 99 mol% relative to the number of moles of 2-norbornene at the start of the first second polymerization.

[0107] (Addition of the second monomer and alkylaluminum compound) After 10 minutes of reaction, 2-norbornene, 1 / 4 of 1-octene, and 0.016 mmol of trimethylaluminum were added to the Schlenk flask.

[0108] (Second polymerization) The addition polymerization reaction was then continued for 10 minutes. The reaction rate of 2-norbornene after a total reaction time of 20 minutes in the second polymerization was 96 mol% relative to the number of moles of 2-norbornene at the start of the second polymerization.

[0109] (Third addition of monomer and alkylaluminum compound) After 10 minutes of reaction, 2-norbornene, 1 / 4 of 1-octene, and 0.016 mmol of trimethylaluminum were added to the Schlenk flask.

[0110] (Third polymerization) The addition polymerization reaction was then continued for 10 minutes. The reaction rate of 2-norbornene after a total reaction time of 30 minutes in the second polymerization was 82 mol% relative to the number of moles of 2-norbornene at the start of the third second polymerization.

[0111] After a total reaction time of 40 minutes, a small amount of 2-propanol was added to the reaction mixture to stop the addition polymerization reaction. Hydrochloric acid was added to the reaction mixture and stirred for 10 minutes, after which the organic layer was washed with deionized water. Washing with deionized water was repeated until the aqueous layer became neutral, and then the washed organic layer was collected. The collected organic layer was added dropwise to a large amount of acetone to precipitate the resulting cyclic olefin copolymer. The precipitated copolymer was collected by filtration, and then washed with methanol and acetone at least twice. The washed copolymer was dried under reduced pressure at 110°C for at least 16 hours to obtain a dried cyclic olefin copolymer.

[0112] [Example 2] A cyclic olefin copolymer was obtained in the same manner as in Example 1, except that trimethylaluminum was replaced with an equimolar mixture of tri-n-octylaluminum and trimethylaluminum. The charging ratios of norbornene and 1-octene are as shown in Table 1. Furthermore, for each polymerization step in Example 2, the reaction rate of 2-norbornene at the end of each polymerization step relative to the number of moles of 2-norbornene at the start of each polymerization step is shown in Table 2.

[0113] After a total reaction time of 40 minutes, a cyclic olefin copolymer was obtained in the same manner as in Example 1.

[0114] [Example 3] A cyclic olefin copolymer was obtained in the same manner as in Example 1, except that trimethylaluminum was replaced with an equimolar mixture of triisobutylaluminum and trimethylaluminum. The charging ratios of norbornene and 1-octene are as shown in Table 1. Furthermore, for each polymerization step in Example 3, the reaction rate of 2-norbornene at the end of each polymerization step relative to the number of moles of 2-norbornene at the start of each polymerization step is shown in Table 2.

[0115] After a total reaction time of 40 minutes, a cyclic olefin copolymer was obtained in the same manner as in Example 1.

[0116] [Examples 4-6] In Examples 4 to 6, cyclic olefin copolymers were obtained in the same manner as in Examples 1 to 3, except that 1-octene was replaced with 1-hexene (Hex). In other words, the conditions of Example 1 and Example 4 are the same except for the type of monomer. Similarly, the conditions of Example 2 and Example 5, and the conditions of Example 3 and Example 6 are the same except for the type of monomer.

[0117] [Comparative Example 1] 2-norbornene (Nb) and 1-octene (Oct) were used in the proportions listed in Table 1, in amounts such that the total amount of 2-norbornene and 1-octene was 118.8 mmol. (First polymerization) In a 500 mL round-bottom flask, under a nitrogen atmosphere, half the amount of 2-norbornene and 1-octene, along with 0.198 mmol of tri-n-octylaluminum and 0.396 mmol of 2,6-di-tert-butyl-4-hydroxytoluene were added. In other words, in the first polymerization of Comparative Example 1, twice the molar amount of 2,6-di-tert-butyl-4-hydroxytoluene was used relative to the moles of tri-n-octylaluminum. Next, the contents of the flask were diluted with decalin to a volume of 258 mL. Then, the contents of the flask were cooled to 0°C. After cooling, a toluene solution of titanocene catalyst with a concentration of 0.04 mmol / L was added to the reaction mixture so that the amount of titanocene catalyst was 0.22 mmol. Then, a toluene solution of borate compound with a concentration of 0.008 mmol / L was added to the reaction mixture so that the amount of borate compound was 0.22 mmol. Triphenylmethylium tetrakis(pentafluorophenyl) borate was used as the borate compound. After adding the titanocene catalyst and borate compound to initiate addition polymerization, the reaction mixture was stirred with a magnetic stirrer and carried out at 0°C for 10 minutes. The reaction rate of 2-norbornene was 99 mol% relative to the number of moles of 2-norbornene at the start of polymerization.

[0118] (Second polymerization) After 10 minutes of reaction, half of the 2-norbornene and 1-octene, along with 0.022 mmol of tri-n-octylaluminum and 0.044 mmol of 2,6-di-tert-butyl-4-hydroxytoluene, were added to a round-bottom flask. The addition polymerization reaction was then continued for 15 minutes. The reaction rate of 2-norbornene after the second polymerization was 99 mol% relative to the number of moles of 2-norbornene at the start of the second polymerization.

[0119] After a total reaction time of 25 minutes, a cyclic olefin copolymer was obtained in the same manner as in Example 1.

[0120] [Comparative Example 2] 2-norbornene (Nb) and 1-octene (Oct) were used in the proportions listed in Table 1, in quantities such that the total amount of 2-norbornene and 1-octene was 118.8 mmol. In a 500 mL round-bottom flask, under a nitrogen atmosphere, 2-norbornene, 1-octene, 0.97 mmol of CC1 (listed below), and 0.68 mmol of CC2 (listed below) were added. The contents of the flask were then diluted with toluene to a volume of 258 mL. Next, the contents of the flask were heated to 40°C. After heating, a toluene solution of titanocene catalyst with a concentration of 0.04 mmol / L was added to the reaction mixture so that the amount of titanocene catalyst was 0.22 mmol. After adding the titanocene catalyst to initiate addition polymerization, the reaction was carried out at 40°C for 4 hours while stirring the reaction mixture with a magnetic stirrer.

[0121] After 4 hours of reaction, a small amount of 2-propanol was added to the reaction mixture to stop the addition polymerization reaction. Hydrochloric acid was added to the reaction mixture and stirred for 10 minutes, after which the organic layer was washed with deionized water. Washing with deionized water was repeated until the aqueous layer became neutral, and then the washed organic layer was collected. The collected organic layer was added dropwise to a large amount of acetone to precipitate the resulting cyclic olefin copolymer. The precipitated copolymer was collected by filtration, and then washed with methanol and acetone at least twice. The washed copolymer was dried under reduced pressure at 110°C for at least 16 hours to obtain a dried cyclic olefin copolymer. CC1: 6.5% by mass (as Al atom content) MMAO-3A toluene solution ([(CH3) 0.7 (iso-C4H9) 0.3 AlO] n A solution of methylisobutylaluminoxane represented by [formula], manufactured by Tosoh Finechem Co., Ltd. (Note: It contains 6 mol% trimethylaluminum relative to total Al.) CC2: 9.0% by mass (as Al atom content) TMAO-211 toluene solution (methylaluminoxane solution, manufactured by Tosoh Finechem Co., Ltd., containing 26 mol% trimethylaluminum relative to total Al)

[0122] [Comparative Example 3] A cyclic olefin copolymer was obtained in the same manner as in Example 1, except that the reaction times for the first polymerization and the second polymerization were changed to the reaction times shown in Table 1, respectively.

[0123] For the cyclic olefin copolymers obtained in Examples 1-6 and Comparative Examples 1-3, the molecular weight was measured by gel permeation chromatography, and the glass transition temperature was measured by the method described above. The results of these measurements are shown in Table 3. A cyclic olefin copolymer can be said to have excellent toughness if it has at least one glass transition temperature in the range of below 0°C, in the range of 0 to 100°C, and in the range of 160 to 300°C. Furthermore, the examples in Japanese Patent Application Publication No. 2022-030194 show that having at least one glass transition temperature in the range of less than 0°C, the range of 0 to 100°C, and the range of 160 to 300°C results in excellent toughness.

[0124] The film used as a sample in the measurement of the glass transition temperature was prepared by the following method. A mold with a depth of 50 μm was prepared using a Kapton® film measuring 10 cm × 10 cm × 50 μm. After filling the mold with the obtained cyclic olefin copolymer, the cyclic olefin copolymer filled in the mold was vacuum pressed using a hot vacuum press under the conditions of a pressure of 15 MPa, a temperature of 320-340°C, and a time of 15 minutes. After pressing, the pressed cyclic olefin copolymer was heated to room temperature in a metal board The material was rapidly cooled by sandwiching it between two metal plates. After cooling, the metal plates were removed to obtain a cyclic olefin copolymer film with a thickness of approximately 50 μm.

[0125] [Table 1]

[0126] [Table 2]

[0127] [Table 3]

[0128] Tables 1 to 3 show that by producing a cyclic olefin copolymer having units derived from a cyclic olefin monomer and units derived from an α-olefin with 3 to 20 carbon atoms using the predetermined method described above, a cyclic olefin copolymer with excellent toughness can be efficiently produced. On the other hand, even when both first and second polymerization were performed, in Comparative Example 1, where a large amount of hindered phenol was used relative to the alkylaluminum compound in the first polymerization, in Comparative Example 2, where polymerization was performed in one step, and in Comparative Example 3, where the reaction rate of the cyclic olefin monomer in the first polymerization was less than 80 mol%, it was not possible to achieve both good 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 having 6 to 10 carbon atoms, The aforementioned manufacturing method A first polymerization is carried out in a polymerization vessel in the presence of a titanocene catalyst, an alkylaluminum compound, and a borate compound, in which the cyclic olefin monomer and the monomer containing the α-olefin are polymerized. Adding the monomer and the alkylaluminum compound to the polymerization vessel after the first polymerization, The process includes a second polymerization in which the monomer is further polymerized after the addition of the monomer and the alkylaluminum compound. In the first polymerization, polymerization of the monomer is carried out until the reaction rate of the cyclic olefin monomer reaches 80 mol% or more relative to the number of moles of the cyclic olefin monomer added to the polymerization vessel at the start of the first polymerization. A method for producing a cyclic olefin copolymer, wherein the amount of hindered phenol used in the first polymerization is such that the amount of phenolic hydroxyl groups in the hindered phenol is 1.5 moles or less per mole of the alkylaluminum compound, The cyclic olefin monomers are 2-norbornene, 5-methyl-bicyclo[2.2.1]hepta-2-ene, 5,5-dimethyl-bicyclo[2.2.1]hepta-2-ene, 5-ethyl-bicyclo[2.2.1]hepta-2-ene, 5-butyl-bicyclo[2.2.1]hepta-2-ene, 5-ethylidene-bicyclo[2.2.1]hepta-2-ene, and 5-hexy Rubicyclo[2.2.1]hepta-2-ene, 5-octyl-bicyclo[2.2.1]hepta-2-ene, 5-octadecyl-bicyclo[2.2.1]hepta-2-ene, 5-methylidene-bicyclo[2.2.1]hepta-2-ene, 5-vinyl-bicyclo[2.2.1]hepta-2-ene, or 5-propenyl-bicyclo[2.2.1]hepta-2-ene, A method for producing a cyclic olefin copolymer, wherein the α-olefin is 1-hexene, 1-heptene, 1-octene, 1-nonene, or 1-decene.

2. A 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. After the first second polymerization, the addition of the monomer and the alkylaluminum compound, and the second polymerization are repeated until the number of additions of the monomer and the alkylaluminum compound reaches n. Un is an integer greater than or equal to 2, The addition of the monomer and the alkylaluminum compound for the 2nd to nth times is performed after the reaction rate of the cyclic olefin monomer in the (p-1)th second polymerization has reached 80 mol% or more relative to the number of moles of the cyclic olefin monomer in the polymerization vessel at the start of the (p-1)th second polymerization. The aforementioned p is an integer between 2 and n, A method for producing a cyclic olefin copolymer according to claim 1, wherein the polymerization reaction is terminated after the nth second polymerization.

4. A method for producing a cyclic olefin copolymer according to any one of claims 1 to 3, 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 fewer carbon atoms.

5. From the start of the first polymerization to the end of the second polymerization, both alkylaluminum compound I and alkylaluminum compound II, which is different from alkylaluminum compound I, are used as the alkylaluminum compound. The alkylaluminum compound I has at least one alkyl group having 6 or more carbon atoms, The method for producing a cyclic olefin copolymer according to any one of claims 1 to 3, wherein the alkylaluminum compound II has at least one alkyl group having 5 or fewer carbon atoms.

6. The method for producing a cyclic olefin copolymer according to claim 4, wherein the alkylaluminum compound is at least one selected from the group consisting of trimethylaluminum, triethylaluminum, triisobutylaluminum, and tri-n-octylaluminum.

7. The alkylaluminum compound I is tri-n-octylaluminum, The method for producing a cyclic olefin copolymer according to claim 5, wherein the alkylaluminum compound II is trimethylaluminum, triethylaluminum, or triisobutylaluminum.

8. A method for producing a cyclic olefin copolymer according to any one of claims 1 to 3, wherein the amount of cyclic olefin copolymer obtained 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.

9. The titanocene catalyst is defined by the following formula (1): (In formula (1), R １ ~R ３ Each of these is independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, R ４ and R ５ Each of these is 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 Each of these is a silyl group that may independently have a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a monovalent hydrocarbon group having 1 to 12 carbon atoms as a substituent. A method for producing a cyclic olefin copolymer according to any one of claims 1 to 3, wherein the compound is represented by [the formula shown].

10. The method for producing a cyclic olefin copolymer according to any one of claims 1 to 3, wherein the cyclic olefin copolymer has two or more glass transition temperatures in the range of 0 to 300°C.

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