Cyclic olefin copolymer, solution, film, and method for producing cyclic olefin copolymer

Abstract

The problems addressed by the present invention are to provide a cyclic olefin copolymer having a plurality of glass transition temperatures and good toughness, and a method for producing the same.　The present invention provides a cyclic olefin copolymer which is an addition-type polymer of a norbornene monomer and a C3-20 alpha-olefin, wherein the ratio of the number of mol of structural units derived from the alpha-olefin to the number of mol of all structural units in the cyclic olefin copolymer is 10-90 mol%, the number average molecular weight of the cyclic olefin copolymer is from more than 20,000 to 500,000, and the cyclic olefin copolymer has two or more glass transition temperatures by viscoelasticity measurement within the range of 0-350° C.

Description

Cyclic olefin copolymer, solution, film, and method for producing cyclic olefin copolymer

[0001] The present invention relates to a cyclic olefin copolymer, a solution, a film, and a method for producing the cyclic olefin copolymer.

[0002] Cyclic olefin copolymers are resins that have high transparency and are used in a wide range of fields, such as optical materials.

[0003] On the other hand, attempts have been made to impart even more excellent properties to cyclic olefin copolymers. For example, Patent Document 1 proposes improving durability against bending by combining multiple cyclic olefin copolymers having glass transition temperatures within a predetermined range.

[0004] Japanese Patent Application Laid-Open No. 2023-112594

[0005] On the other hand, cyclic olefin copolymers having multiple glass transition temperatures tend to have poor toughness, and this tendency becomes more pronounced as the glass transition temperature becomes higher.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cyclic olefin copolymer having multiple glass transition temperatures and good toughness, a solution, a film, and a method for producing the cyclic olefin copolymer.

[0007] The present inventors have found that the above-mentioned problems can be solved by adjusting the number average molecular weight and the ratio of the constituent monomers of a cyclic olefin copolymer having multiple glass transition temperatures, and have completed the present invention. More specifically, the present invention provides the following.

[0008] <1> A cyclic olefin copolymer which is an addition polymer of a norbornene monomer and an α-olefin having 3 to 20 carbon atoms, wherein the ratio of the number of moles of structural units derived from the α-olefin to the number of moles of all structural units in the cyclic olefin copolymer is 10 to 90 mol %, the number average molecular weight of the cyclic olefin copolymer is more than 200,000 to 500,000, and the cyclic olefin copolymer has two or more glass transition temperatures within a range of 0 to 350°C as determined by viscoelasticity measurement.

[0009] <2> The cyclic olefin copolymer according to <1>, wherein the α-olefin has 4 to 8 carbon atoms.

[0010] <3> The cyclic olefin copolymer according to <1> or <2>, wherein the cyclic olefin copolymer has at least one glass transition temperature determined by viscoelasticity measurement in the range of 130 to 350°C.

[0011] <4> A solution containing the cyclic olefin copolymer according to any one of <1> to <3> and a solvent.

[0012] <5> A film made from the solution according to <4>.

[0013] <6> A method for producing the cyclic olefin copolymer according to any one of <1> to <3>, comprising addition-polymerizing the norbornene monomer and the α-olefin in the presence of a titanocene catalyst represented by the following formula (1) and a co-catalyst, wherein the co-catalyst contains a borate compound and a hindered phenol, and the total amount of the norbornene monomer and the α-olefin is 1,200 to 1,600 parts by mass per part by mass of the titanocene catalyst: (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 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.

[0014] According to the present invention, there are provided a cyclic olefin copolymer having a plurality of glass transition temperatures and good toughness, a solution, a film, and a method for producing the cyclic olefin copolymer.

[0015] Hereinafter, the cyclic olefin copolymer, the solution, the film, and the method for producing the cyclic olefin copolymer will be described. However, the cyclic olefin copolymer, the solution, the film, and the method for producing the cyclic olefin copolymer are not limited to the specific embodiments described below, and may be appropriately modified as long as the desired effects are not impaired.

[0016] <Cyclic Olefin Copolymer> The cyclic olefin copolymer satisfies the following requirements. - It is an addition polymer of norbornene monomer and an α-olefin having 3 to 20 carbon atoms. - The ratio of the number of moles of structural units derived from α-olefin to the number of moles of all structural units in the cyclic olefin copolymer is 10 to 90 mol %. - The number average molecular weight of the cyclic olefin copolymer is more than 200,000 to 500,000. - The cyclic olefin copolymer has two or more glass transition temperatures within the range of 0 to 350°C as determined by viscoelasticity measurement.

[0017] Conventionally, cyclic olefin copolymers having multiple glass transition temperatures may be prone to poor toughness. This tendency is particularly pronounced when the copolymer has a high glass transition temperature. However, cyclic olefin copolymers that satisfy the above requirements can stably exhibit good toughness despite having multiple glass transition temperatures. The reason for this is unclear, but it is thought that one factor is that a high number average molecular weight, in particular, creates a strong molecular structure, improving strength.

[0018] The "toughness" in the specification of the present application can be evaluated by specifying the number of folding times in a folding endurance test (MIT test) in accordance with JIS P 8115. A higher number of folding times means that the toughness of the cyclic olefin copolymer (or a molded article thereof) is higher.

[0019] The structure of the cyclic olefin copolymer will be described in detail below.

[0020] (1) Addition Polymer The cyclic olefin copolymer is an addition polymer of a monomer containing a norbornene monomer and an α-olefin having 3 to 20 carbon atoms. In the addition polymer, the ratio of the number of moles of structural units derived from the α-olefin to the number of moles of all structural units is 10 to 90 mol %.

[0021] As a result of investigations by the present inventors, it has been found that when preparing an addition polymer having multiple glass transition temperatures, a high number average molecular weight can be easily achieved by adjusting the amount of catalyst, etc., as described below, and as a result, high toughness can also be achieved. In particular, addition polymers having high glass transition temperatures may tend to have poor toughness, but such problems can be solved by using a cyclic olefin copolymer that satisfies the above requirements.

[0022] The above-mentioned cyclic olefin copolymer includes copolymers containing structural units derived from monomers other than the above-mentioned monomers. That is, the cyclic olefin copolymer may have structural units other than the structural units derived from norbornene monomers and the structural units derived from α-olefins having 3 to 20 carbon atoms. However, from the viewpoint of stably achieving high toughness, it is preferable that the cyclic olefin copolymer consists only of structural units derived from norbornene monomers and structural units derived from α-olefins having 3 to 20 carbon atoms.

[0023] (1-1) Norbornene Monomer Norbornene (CAS Registration Number: 498-66-8, Chemical Formula: C ７ H １０ ) is a type of cyclic olefin monomer. Norbornene monomers also include substituted norbornenes, which are norbornenes having a substituent. The norbornene monomers may be used alone or in combination of two or more.

[0024] 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):

[0025]

[0026] 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.

[0027] 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 ~R ａ８ may all consist of different atoms or groups. ａ１ ~R ａ８ Some or all of these may be the same atom or group.

[0028] R ａ９ ~R ａ１２Specific 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.

[0029] R ａ９ and R ａ１０ , or R ａ１１ and R ａ１２ Specific examples of divalent hydrocarbon groups that can be formed by combining the above groups include alkylidene groups such as an ethylidene group, a propylidene group, and an isopropylidene group.

[0030] 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.

[0031] 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 (trivial name: dicyclopentadiene), tricyclo[4.3.0.1 ２，５ ]dec-3-ene; tricyclo[4.4.0.1 ２，５ ]undeca-3,7-diene or tricyclo[4.4.0.1 ２，５ ]undeca-3,8-diene or a partially hydrogenated product thereof (or an adduct of cyclopentadiene and cyclohexene), tricyclo[4.4.0.1 ２，５ ]undec-3-ene; three-ring cyclic olefins such as 5-cyclopentyl-bicyclo[2.2.1]hept-2-ene, 5-cyclohexyl-bicyclo[2.2.1]hept-2-ene, 5-cyclohexenylbicyclo[2.2.1]hept-2-ene, and 5-phenyl-bicyclo[2.2.1]hept-2-ene; tetracyclo[4.4.0.1 ２，５ .1 ７，１０ ] dodec-3-ene (also simply called tetracyclododecene), 8-methyltetracyclo[4.4.0.1 ２，５ .1 ７，１０ ] dodec-3-ene, 8-ethyltetracyclo[4.4.0.1 ２，５ .1 ７，１０ ] dodec-3-ene, 8-methylidenetetracyclo[4.4.0.1 ２，５ .1 ７，１０ ] dodec-3-ene, 8-ethylidenetetracyclo[4.4.0.1 ２，５ .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.

[0032] 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 substituted with one or more alkylidene groups such as bicyclo[2.2.1]hept-2-ene are preferred, with 5-ethylidene-bicyclo[2.2.1]hept-2-ene (common name: 5-ethylidene-2-norbornene, or simply ethylidenenorbornene) being particularly preferred.

[0033] (1-2) α-Olefin The α-olefin is an α-olefin having 3 to 20 carbon atoms. The α-olefin may be used alone or in combination of two or more. From the viewpoint of easily obtaining the desired effect, it is preferable to use one type of α-olefin alone.

[0034] The α-olefin may be either an unsubstituted α-olefin or an α-olefin having a substituent (such as a halogen atom). From the viewpoint of easily achieving the desired effect, an unsubstituted α-olefin is preferred.

[0035] The α-olefin has 3 to 20 carbon atoms, preferably 4 to 12 carbon atoms, more preferably 4 to 10 carbon atoms, even more preferably 4 to 8 carbon atoms, and most preferably 6 to 8 carbon atoms.

[0036] Examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, and 1-dodecene. Of these, 1-hexene, 1-octene, and 1-decene are preferred. Of these, 1-hexene and 1-octene are more preferred, and 1-octene is particularly preferred, from the viewpoint that the desired effects can be easily obtained.

[0037] (1-3) Ratio of Constituent Monomers In the cyclic olefin copolymer, the ratio of the number of moles of structural units derived from α-olefin to the number of moles of all structural units is preferably 10 to 90 mol%, more preferably 10 to 70 mol%, even more preferably 10 to 50 mol%, still more preferably 20 to 40 mol%, and most preferably 20 to 30 mol%. When the ratio of constituent monomers satisfies the above requirement, a cyclic olefin copolymer having the glass transition temperature described below is easily obtained.

[0038] In the cyclic olefin copolymer, the ratio of the number of moles of structural units derived from norbornene monomers to the number of moles of all structural units is not particularly limited, but is preferably 10 to 90 mol%, more preferably 30 to 90 mol%, and even more preferably 50 to 90 mol%.

[0039] The ratio of the number of moles of structural units derived from α-olefin or norbornene monomer to the number of moles of all structural units is １３ It is calculated by measuring the C-NMR spectrum.

[0040] (2) Number Average Molecular Weight and Weight Average Molecular Weight The number average molecular weight of the cyclic olefin copolymer is more than 200,000 to 500,000, preferably 210,000 to 470,000, more preferably 220,000 to 450,000, even more preferably 230,000 to 430,000, and still more preferably 240,000 to 400,000.

[0041] The weight average molecular weight of the cyclic olefin copolymer is not particularly limited, but is preferably 300,000 to 750,000, more preferably 350,000 to 600,000, and even more preferably 400,000 to 550,000.

[0042] The number average molecular weight and the weight average molecular weight are each specified as a polystyrene equivalent value measured by gel permeation chromatography (GPC).

[0043] (3) Glass Transition Temperature The cyclic olefin copolymer has two or more glass transition temperatures (also referred to as "Tg") within the range of 0 to 350°C, preferably 130 to 350°C, and more preferably 200 to 300°C.

[0044] In a preferred embodiment of the present invention, the cyclic olefin copolymer may have two or more glass transition temperatures within the range of 0 to 350°C and one glass transition temperature below 0°C.

[0045] It has been known that, in cyclic olefin copolymers having multiple glass transition temperatures, the higher the glass transition temperature, the more likely the toughness is to decrease. However, it has been found that, by adjusting the number average molecular weight and the proportions of its constituent monomers as described above, good toughness can be achieved even when the glass transition temperature is high. Therefore, in cyclic olefin copolymers satisfying the above requirements, good toughness can be achieved, for example, even in the following embodiments: - An embodiment in which the cyclic olefin copolymer has at least one (e.g., one or two) glass transition temperature preferably between 130 and 350°C. - An embodiment in which the cyclic olefin copolymer has at least one (e.g., one or two) glass transition temperature preferably between 200 and 300°C. - An embodiment in which the cyclic olefin copolymer has one glass transition temperature preferably between 130 and 350°C and one glass transition temperature preferably between 0 and less than 130°C. An embodiment in which the cyclic olefin copolymer has one glass transition temperature preferably between 130 and 350° C., one preferably between 0 and less than 130° C., and one preferably between −50 and less than 0° C. An embodiment in which the cyclic olefin copolymer has one glass transition temperature preferably between 130 and 350° C., one preferably between 40 and 100° C., and one preferably between −50 and −10° C.

[0046] In the specification and claims of the present application, the "glass transition temperature (of a cyclic olefin copolymer)" refers to a value determined by viscoelasticity measurement. Specifically, as shown in the examples, the glass transition temperature is measured by observing the viscoelastic behavior of a 50 μm-thick film obtained from the cyclic olefin copolymer at temperatures from −100 to 300° C. using a solid-state rheometer. The glass transition temperature is determined by the peak top temperature in the tan δ chart obtained by the measurement.

[0047] (4) Uses of the Cyclic Olefin Copolymer The cyclic olefin copolymer can be used for any purpose. For example, by blending the above-mentioned cyclic olefin copolymer in place of or together with a conventional cyclic olefin copolymer as a raw material, good toughness can be imparted to the resulting resin molded article.

[0048] In one embodiment of the present invention, the cyclic olefin copolymer may be formed into a film by any molding method (melt extrusion, vacuum pressing (heat vacuum pressing, etc.), etc.). The present invention also encompasses molded articles obtained by such methods.

[0049] (5) Solution One aspect of the present invention encompasses a solution containing a cyclic olefin copolymer and a solvent.

[0050] The solution can be prepared by blending the above-mentioned cyclic olefin copolymer with any solvent. The method for producing the solution is not particularly limited. Typically, the solution is obtained by uniformly dissolving or dispersing the desired types and amounts of each component of the solution. If the cyclic olefin copolymer is difficult to dissolve in the solvent, the solvent containing the cyclic olefin copolymer may be heated as necessary.

[0051] Such a solution can be used in a variety of applications, including the following: Raw material for films (described later) Raw material for paints Varnish used to coat metal wiring, etc. Spinning to produce cyclic olefin copolymer fibers

[0052] The solvent for the solution is not particularly limited as long as it can dissolve the cyclic olefin copolymer, and examples thereof include aliphatic hydrocarbon solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, p-menthane, and decahydronaphthalene; aromatic hydrocarbon solvents such as toluene and xylene; and halogenated hydrocarbon solvents such as dichloromethane, chloroform, and carbon tetrachloride. Of these, cyclohexane, methylcyclohexane, dimethylcyclohexane, p-menthane, toluene, and xylene are preferred. The solvents can be used alone or in combination of two or more.

[0053] The amount of solvent used in the solution can be appropriately set taking into consideration the use of the solution, the concentration of components other than the solvent, etc. Typically, the amount of solvent used is preferably such that the concentration of components other than the solvent in the solution is 1.0 to 50.0 mass %, more preferably 5.0 to 40.0 mass %. When the concentration of components other than the solvent in the solution is within the above range, it is easy to form a film of the desired thickness from the solution.

[0054] Any components other than the solvent in the solution can be used as long as they do not impair the object of the present invention. Examples of such components include known additives and solvent-soluble resins (other than cyclic olefin copolymers).

[0055] Additives include, but are not limited to, fillers, reinforcing agents, surface treatment agents, antioxidants, UV absorbers, flame retardants, colorants, adhesion enhancers, etc. As fillers and reinforcing agents, particulate fillers, scaly fillers, and whiskers (short fibers) are preferred in terms of film-forming properties of the solution. Specific examples of fillers and reinforcing agents include silica, alumina, talc, aluminum hydroxide, magnesium hydroxide, titanium oxide, mica, aluminum borate, potassium titanate, barium sulfate, boron nitride, forsterite, zinc oxide, magnesium oxide, and calcium carbonate. Furthermore, hollow particles such as hollow silica, glass balloons, and various hollow resin particles can be used as fillers to improve dielectric properties in the high-frequency band. The fillers and reinforcing agents may be surface-treated with a surface treatment agent having a polymerizable unsaturated bond. Examples of the polymerizable unsaturated bond include a vinyl group, an allyl group, a metallic group, a styryl group, an acryloyl group, a methacryloyl group, and a maleimide group. Examples of the surface treatment agent include a silane coupling agent having a polymerizable unsaturated bond.

[0056] The solvent-soluble resin is not particularly limited, but from the viewpoint of not impairing the effects of the present invention, a polymer having a relatively low polarity is preferred. Examples of the polymer having a relatively low polarity include an aliphatic polyimide resin, a polyphenylene ether resin, and a modified polyphenylene ether resin.

[0057] When the solution contains the additives described above, the ratio of the mass of the other additives to the total mass of the cyclic olefin copolymer and the mass of the other additives can be adjusted appropriately depending on the effect to be obtained.

[0058] (6) Film One aspect of the present invention includes a film made from the above-described solution. Such a film can be produced by applying the solution to a substrate or the like by a solution casting method or the like and removing the solvent from the solution, and can be called a cast film.

[0059] The method for producing a cast film is not particularly limited. For example, a cast film can be produced by the following method. First, a solution is applied to a support composed of a resin film, metal foil, or the like. The coating method is not particularly limited. Examples of known coating methods that can be used include dip coating, roll coating, curtain coating, die coating, slit coating, microgravure coating, comma coating, and spin coating. The thickness of the cast film can be adjusted by adjusting the amount of solution applied. Therefore, the amount of application is determined appropriately taking into account the intended use of the cast film, etc. Next, the solvent is removed from the coating film on the support composed of the solution to obtain a cast film. The solvent can be removed by heating the coating film, placing the coating film in a reduced pressure atmosphere, or a combination of heating the coating film and placing the coating film in a reduced pressure atmosphere.

[0060] The film obtained in this manner has excellent toughness and excellent folding resistance, and is therefore suitable for use in optical applications, medical applications, packaging applications, and electrical and electronic component applications.

[0061] <Method for Producing Cyclic Olefin Copolymer> The cyclic olefin copolymer can be stably produced by, for example, a production method that satisfies the following requirements. However, the method for producing the cyclic olefin copolymer is not limited to the method described below. - It includes addition polymerization of a norbornene monomer and an α-olefin in the presence of a titanocene catalyst represented by formula (1) described below and a co-catalyst. - The co-catalyst contains a borate compound and a hindered phenol. - The total amount of the norbornene monomer and the α-olefin per part by mass of the titanocene catalyst is 1,200 to 1,600 parts by mass.

[0062] (1) Components Used in Addition Polymerization Addition polymerization is carried out using raw material monomers including norbornene monomer and α-olefin in the presence of a predetermined titanocene catalyst and co-catalyst.

[0063] (1-1) Titanocene Catalyst As the titanocene catalyst, a titanocene compound represented by the following formula (1) is used.

[0064]

[0065] (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 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.

[0066] As the titanocene catalyst, from the viewpoint of easily obtaining a copolymer satisfying the above-mentioned predetermined requirements, a titanium complex represented by the following formula (2) "(t-BuNSiMe ２ Flu)TiMe ２ " is preferred.

[0067]

[0068] (In the formula, Me represents a methyl group, and t-Bu represents a tert-butyl group.)

[0069] The main technical feature of the method for producing a cyclic olefin copolymer is that the amount of raw material monomers charged (the total amount of norbornene monomer and α-olefin per part by mass of titanocene catalyst) is 1,200 to 1,600 parts by mass. This amount is higher than conventionally charged (i.e., the relative amount of catalyst used is smaller than conventionally). In such a case, according to conventional knowledge, a decrease in reaction activity (yield) would be predicted. However, surprisingly, no such decrease was observed, and it was possible to achieve a copolymer with a high molecular weight.

[0070] The amount of the titanocene catalyst in the addition polymerization is not particularly limited as long as the addition polymerization reaction proceeds smoothly. The amount of the titanocene catalyst in the addition polymerization may be, for example, 0.0030 to 0.0040 mmol.

[0071] The amount of monomers charged (total amount of norbornene monomer and α-olefin per part by mass of titanocene catalyst) is 1,200 to 1,600 parts by mass, preferably 1,300 to 1,500 parts by mass.

[0072] (1-2) Promoter The promoter contains at least a borate compound and a hindered phenol, and preferably contains a borate compound and a hindered phenol.

[0073] (1-2-1) Borate Compounds As the borate compounds, any compounds that are used as co-catalysts in the copolymerization of cyclic olefin monomers can be used.

[0074] 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. Of these, triphenylmethylium tetrakis(pentafluorophenyl)borate is preferred from the viewpoint of facilitating the production of a copolymer that satisfies the above-mentioned specific requirements.

[0075] The amount of the borate compound used is not particularly limited as long as the addition polymerization reaction proceeds smoothly and the desired cyclic olefin copolymer is obtained. For example, the amount of the borate compound used is preferably 0.01 to 100 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of the total amount of the norbornene monomer and the α-olefin.

[0076] (1-2-2) Hindered Phenols As the hindered phenol, any of those used as a co-catalyst in the copolymerization of cyclic olefin monomers can be used.

[0077] In the specification and claims of this application, a "hindered phenol" refers to a phenol having a bulky substituent at at least one of the two adjacent positions to the phenolic hydroxyl group. In the specification of this application, the term "bulky substituent" includes alkyl groups other than methyl groups (such as isopropyl, isobutyl, sec-butyl, and tert-butyl), alkenyl groups, alkynyl groups, aryl groups, heterocyclic groups, alkoxy groups, aryloxy groups, substituted amino groups, alkylthio groups, and arylthio groups.

[0078] 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, 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 is preferred from the viewpoint that a copolymer satisfying the above-mentioned predetermined requirements can be easily obtained.

[0079] The amount of the hindered phenol used is not particularly limited as long as the addition polymerization reaction proceeds smoothly and the desired cyclic olefin copolymer is obtained. For example, the amount of the hindered phenol used is preferably 0.001 to 100 parts by mass, more preferably 0.01 to 10 parts by mass, and even more preferably 0.1 to 1 part by mass, relative to 100 parts by mass of the total amount of the norbornene monomer and the α-olefin.

[0080] (2) Addition Polymerization Conditions Other addition polymerization conditions are not particularly limited as long as the addition polymerization reaction proceeds smoothly and the desired cyclic olefin copolymer is obtained.

[0081] In the addition polymerization, the components to be subjected to the reaction (norbornene monomer, α-olefin, etc.) may be added to a reaction vessel simultaneously or separately.

[0082] The addition polymerization may be 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. When a solvent is used, the amount used is not particularly limited and is appropriately determined depending on the amount of monomer, etc.

[0083] The temperature of the addition polymerization is not particularly limited and may be, for example, from −20 to 200° C.

[0084] The time for addition polymerization is not particularly limited, and may be, for example, 0.25 to 2 hours.

[0085] The atmosphere in which the addition polymerization reaction is carried out is not particularly limited as long as the reaction is not inhibited, and the atmosphere in which the addition polymerization reaction is carried out is preferably an inert gas atmosphere (nitrogen gas, helium gas, etc.).

[0086] After the addition polymerization is completed, the cyclic olefin copolymer can be recovered from the reaction vessel in a conventional manner.

[0087] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0088] <Preparation of Cyclic Olefin Copolymer> Cyclic olefin copolymers according to Examples and Comparative Examples were prepared by the following method.

[0089] The terms used in this test have the following meanings. "Nb": 2-norbornene "Oct": 1-octene "Hex": 1-hexene "BHT": 2,6-di-tert-butyl-4-hydroxytoluene (corresponding to hindered phenol) "Charged amount": total amount of charged monomers relative to 1 part by mass of catalyst "Copolymer (g) / Catalyst (g)": amount of the obtained cyclic olefin copolymer relative to the amount of catalyst "α-olefin ratio": ratio of the number of moles of structural units derived from 1-octene or 1-hexene to the number of moles of all structural units in the obtained cyclic olefin copolymer (the type of α-olefin used is shown in parentheses in the table) "Mw": weight average molecular weight "Mn": number average molecular weight "Tg": glass transition temperature "CC1": 6.5% by mass (as the content of Al atoms) MMAO-3A toluene solution ([ (CH ３ ) ０．７ (iso-C ４ H ９ ) ０．３ AlO] ｎ(manufactured by Tosoh Finechem Corporation, containing 6 mol% trimethylaluminum based on the total Al). "CC2": 9.0 mass% (as Al atom content) TMAO-211 toluene solution (a solution of methylaluminoxane, manufactured by Tosoh Finechem Corporation, containing 26 mol% trimethylaluminum based on the total Al).

[0090] In all of these test examples, a titanium complex represented by the following formula (2) "(t-BuNSiMe ２ Flu)TiMe ２ " was used.

[0091]

[0092] (In the formula, Me represents a methyl group, and t-Bu represents a tert-butyl group.)

[0093] (1) Example 1 2-Norbornene and 1-octene 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. To a 50 mL Schlenk flask purged with nitrogen, the total amount of 2-norbornene and 1-octene, 0.0032 mmol of tri-t-butyl ether, and 0.0064 mmol of 2,6-di-tert-butyl-4-hydroxytoluene were added. The resulting mixture was diluted with decalin to a volume of 18.6 mL. The contents of the flask were then cooled to 0°C. After cooling, a toluene solution of titanocene catalyst at a concentration of 0.032 mmol / mL was added to the reaction solution to adjust the amount of titanocene catalyst to 0.0032 mmol. Next, a toluene solution of borate compound with a concentration of 0.008 mmol / L was added to the reaction solution so that the amount of borate compound was 0.0032 mmol. Triphenylmethylium tetrakis(pentafluorophenyl)borate was used as the borate compound. After initiating addition polymerization by adding a titanocene catalyst and a borate compound, the reaction solution was stirred with a magnetic stirrer while the addition polymerization reaction continued at 0°C for 30 minutes. After 30 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, after which the organic layer was washed with ion-exchanged water. The aqueous layer was repeatedly washed with ion-exchanged water until it 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 resulting 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, and the dried product was recovered as the cyclic olefin copolymer according to Example 1.

[0094] (2) Example 2 A cyclic olefin copolymer according to Example 2 was obtained by synthesis in the same manner as in Example 1, except that the total amount of monomers charged relative to the catalyst was changed to 1,780 parts by mass.

[0095] (3) Example 3 A cyclic olefin copolymer according to Example 3 was obtained by synthesis in the same manner as in Example 1, except that decalin was changed to toluene.

[0096] (4) Examples 4 to 6 Cyclic olefin polymers according to Examples 4 to 6 were obtained by synthesizing in the same manner as in Example 1, except that the type of α-olefin and / or the ratio of the charged monomers was changed to those shown in the table.

[0097] (5) Comparative Examples 1-1 to 1-3: 2-Norbornene and 1-octene were used in the ratios shown in Table 2, with the total amount of 2-norbornene and 1-octene being 118.8 mmol. Half of the 2-norbornene and 1-octene, 0.198 mmol of tri-n-octylaluminum, and 0.396 mmol of 2,6-di-tert-butyl-4-hydroxytoluene were added to a 500 mL eggplant-shaped flask purged with nitrogen. The resulting mixture was diluted with decalin to a volume of 258 mL. The contents of the flask were then cooled to 0°C. After cooling, a toluene solution of titanocene catalyst at a concentration of 0.04 mmol / L was added to the reaction solution to adjust the amount of titanocene catalyst to 0.22 mmol. Next, a toluene solution containing a borate compound at a concentration of 0.008 mmol / L was added to the reaction solution to adjust the amount of borate compound to 0.22 mmol. Triphenylmethylium tetrakis(pentafluorophenyl)borate was used as the borate compound. After initiating addition polymerization by adding a titanocene catalyst and a borate compound, the reaction solution was stirred with a magnetic stirrer while the addition polymerization reaction was continued for 10 minutes at 0°C. After 10 minutes of reaction, the remaining half of the monomers (2-norbornene and 1-octene), 0.022 mmol of tri-n-octylaluminum, and 0.044 mmol of 2,6-di-tert-butyl-4-hydroxytoluene were added to the eggplant-shaped flask. The addition polymerization reaction was then continued for 15 minutes. After a total of 25 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, after which the organic layer was washed with ion-exchanged water. The mixture was repeatedly washed with ion-exchanged water until the aqueous layer became neutral, and then the washed organic layer was recovered. The recovered organic layer was added dropwise to a large amount of acetone to precipitate the resulting 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, and the dried product was recovered as the cyclic olefin copolymer according to Comparative Example 1-1 to Comparative Example 1-3.

[0098] (6) Comparative Examples 2-1 to 2-3: 2-Norbornene and 1-octene were used in the ratios shown in Table 2, in amounts such that the total amount of 2-norbornene and 1-octene was 118.8 mmol. The total amount of 2-norbornene and 1-octene, 0.198 mmol of tri-n-octylaluminum, and 0.396 mmol of 2,6-di-tert-butyl-4-hydroxytoluene were added to a 500 mL eggplant-shaped flask purged with nitrogen. The resulting mixture was diluted with decalin to a volume of 258 mL. The contents of the flask were then cooled to 25°C. After cooling, a toluene solution of titanocene catalyst at a concentration of 0.04 mmol / L was added to the reaction solution to adjust the amount of titanocene catalyst to 0.22 mmol. Next, a toluene solution of a borate compound with a concentration of 0.008 mmol / L was added to the reaction solution so that the amount of borate compound was 0.22 mmol. Triphenylmethylium tetrakis(pentafluorophenyl)borate was used as the borate compound. After initiating addition polymerization by adding a titanocene catalyst and a borate compound, the reaction solution was stirred with a magnetic stirrer while the addition polymerization reaction was carried out at 25°C for 15 minutes. After 15 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, after which the organic layer was washed with ion-exchanged water. The aqueous layer was repeatedly washed with ion-exchanged water until it 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 resulting 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, and the dried product was collected as the cyclic olefin copolymer according to Comparative Example 2-1 to Comparative Example 2-3.

[0099] (7) Comparative Examples 3-1 to 3-3 2-Norbornene and 1-octene were used in the ratios shown in Table 2, 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, and 0.68 mmol of CC2 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 was carried out at 40°C for 4 hours while stirring the reaction solution with a magnetic stirrer. After 4 hours 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, and the dried product was recovered as the cyclic olefin copolymer according to Comparative Example 3-1 to Comparative Example 3-3.

[0100] (8) Evaluation The molecular weight, glass transition temperature, and toughness of each of the copolymers obtained were determined by the following methods. The results are shown in Tables 1 and 2.

[0101] The glass transition temperature and toughness were evaluated using films of each copolymer prepared according to the following method. A mold with a depth of 50 μm was prepared using Kapton (registered trademark) film (size: 10 cm × 10 cm × 50 μm). Each copolymer was filled into the mold and vacuum-pressed using a thermal vacuum press. The vacuum pressing conditions were set to a pressure of 15 MPa, a temperature of 320 to 340°C, and a time of 15 minutes. After pressing, each pressed copolymer was rapidly cooled by sandwiching it between metal plates at room temperature. After cooling, the metal plates were removed to obtain films of each copolymer (film thickness approximately 50 μm).

[0102] (8-1) 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 device 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

[0103] (8-2) Glass Transition Temperature The glass transition temperature was measured by observing the viscoelastic behavior of a film (thickness: 50 μm) prepared from each copolymer 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-mentioned measurement was taken as the glass transition temperature.

[0104] (8-3) Toughness A folding endurance test (MIT test) in accordance with JIS P 8115 was conducted to evaluate the toughness of each copolymer. Specifically, using a film prepared from each copolymer, the MIT test was conducted using an MIT folding endurance fatigue tester (manufactured by Toyo Seiki Seisakusho, 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.

[0105] The detailed conditions of the MIT test are as follows: Loading method: spring load Load: 1 kgf Bending angle: 135° Bending speed: 175 cpm

[0106] (8-4) Preparation of Resin Film (Cast Film) Each polymer (10 g) of Examples 1 to 6 was dissolved in toluene (90 g) to prepare a 10% by mass toluene solution. The resulting solution was applied to a PET film using a film applicator (manufactured by Tester Sangyo Co., Ltd., "SA202 Doctor Blade", gap thickness 250 μm), dried at 90°C for 8 minutes, and then further dried at 100°C for 12 hours in a vacuum dryer to obtain a cast film. The film thickness was set to 25 μm. It was confirmed that cast films could be successfully formed for all of the polymers of Examples 1 to 6.

[0107]

[0108]

[0109] As shown in "Example 1" to "Example 6," cyclic olefin copolymers satisfying the requirements of the present invention were obtained. The copolymers had high Tg and high toughness.

[0110] It has been known that copolymers having multiple Tg's tend to have low toughness, particularly those having a high Tg (e.g., above 200°C) like the copolymer of "Example 1." However, the cyclic olefin copolymer satisfying the above-mentioned specific requirements was able to unexpectedly achieve both a high Tg and high toughness.

[0111] Furthermore, in "Example 1" to "Example 6," the charged amount is high (i.e., the relative amount of catalyst used is small compared to "Comparative Example 1-1," etc.). In such cases, according to conventional knowledge, it is predicted that the reaction activity (yield) will decrease. However, surprisingly, no such decrease was observed, and it was possible to achieve a copolymer with a high molecular weight.

[0112] In contrast, as shown in "Comparative Example 1-1" to "Comparative Example 1-3" and "Comparative Example 2-1" to "Comparative Example 2-3," these copolymers had low number average molecular weights and could not be made into high molecular weights. In particular, in "Comparative Example 1-1," both the number average molecular weight and toughness were low even though the charged monomer conditions were the same as in "Example 1."

[0113] In "Comparative Example 3-2" and "Comparative Example 3-3," the copolymers were able to have a high molecular weight, but the toughness was extremely low.

Claims

1. A cyclic olefin copolymer which is an addition polymer of a norbornene monomer and an α-olefin having 3 to 20 carbon atoms, wherein the ratio of the number of moles of structural units derived from the α-olefin to the number of moles of all structural units in the cyclic olefin copolymer is 10 to 90 mol %, the number average molecular weight of the cyclic olefin copolymer is more than 200,000 to 500,000, and the cyclic olefin copolymer has two or more glass transition temperatures within the range of 0 to 350°C as determined by viscoelasticity measurement.

2. The cyclic olefin copolymer according to claim 1, wherein the α-olefin has 4 to 8 carbon atoms.

3. The cyclic olefin copolymer according to claim 1, which has at least one glass transition temperature determined by viscoelasticity measurement in the range of 130 to 350°C.

4. A solution comprising the cyclic olefin copolymer according to any one of claims 1 to 3 and a solvent.

5. A film made from the solution according to claim 4.

6. A method for producing the cyclic olefin copolymer according to any one of claims 1 to 3, comprising addition polymerizing the norbornene monomer and the α-olefin in the presence of a titanocene catalyst represented by the following formula (1) and a co-catalyst, wherein the co-catalyst comprises a borate compound and a hindered phenol, and the total amount of the norbornene monomer and the α-olefin per part by mass of the titanocene catalyst is 1,200 to 1,600 parts by mass. (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; 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.

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