Purification method, monomer composition, polymer composition, resin composition, resin molding, and method for producing resin molding

Abstract

To provide a purification method for a treatment object containing a norbornene imide monomer, or a cyclic olefin ring-opening polymer containing a structural unit derived from a norbornene imide monomer, and a monomer composition containing a norbornene imide monomer in which coloring is sufficiently suppressed, and a polymer composition containing a cyclic olefin ring-opening polymer in which coloring is sufficiently suppressed.SOLUTION: A purification method includes the steps of: preparing a treatment object containing a norbornene imide monomer, or a cyclic olefin ring-opening polymer containing a structural unit derived from a norbornene imide monomer; and purifying the treatment object using an adsorbent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a purification method, a monomer composition, a polymer composition, a resin composition, a resin molded article, and a method for producing a resin molded article. [Background technology]

[0002] Hydrogenated cyclic olefin ring-opening polymers obtained by hydrogenating cyclic olefin ring-opening polymers obtained by ring-opening polymerization of cyclic olefin monomers are widely used as molding materials for optical elements such as optical lenses because they have excellent transparency, low moisture absorption, heat resistance, insulating properties, chemical resistance, etc. In recent years, among cyclic olefin ring-opening polymers, development has focused on cyclic olefin ring-opening polymers obtained by ring-opening polymerization of norbornene compounds as cyclic olefin monomers.

[0003] For example, Patent Document 1 discloses an alicyclic structure polymer obtained by ring-opening polymerization of a specific norbornene imide as a cyclic olefin ring-opening polymer, and Patent Document 1 describes that the alicyclic structure polymer has excellent low birefringence. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-052326 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the inventors have found that cyclic olefin ring-opening polymers produced using norbornene imide monomers are sometimes colored and are therefore unsuitable for applications requiring transparency. Furthermore, the inventors have also found that the raw material norbornene imide monomer is colored. Therefore, it was necessary to suppress the coloration of the norbornene imide monomer and the cyclic olefin ring-opening polymers.

[0006] Therefore, an object of the present invention is to provide a method for purifying a treatment target containing a norbornene imide monomer or a cyclic olefin ring-opening polymer containing a structural unit derived from a norbornene imide monomer. Another object of the present invention is to provide a monomer composition containing a norbornene imide monomer in which coloration is sufficiently suppressed, and a polymer composition containing a cyclic olefin ring-opening polymer in which coloration is sufficiently suppressed. A further object of the present invention is to provide a resin composition that can be advantageously used as a material for various molded articles such as optical elements, a resin molded article formed using the resin composition, and a method for producing the resin molded article. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above problems, and have newly discovered that norbornene imide monomers having a predetermined structure are colored, and that the coloration can be reduced by removing impurities that cause the coloration using an adsorbent, thereby completing the present invention.

[0008] That is, an object of the present invention is to advantageously solve the above-mentioned problems, and the present invention provides a method for producing a norbornene imide monomer represented by the following formula (1) or a cyclic olefin ring-opening polymer containing a structural unit derived from the norbornene imide monomer represented by the following formula (1), comprising the steps of: [1] preparing a processing object containing a norbornene imide monomer represented by the following formula (1) or a cyclic olefin ring-opening polymer containing a structural unit derived from the norbornene imide monomer represented by the following formula (1); and purifying the object to be treated using an adsorbent. [ka] (In formula (1), R1 to R5 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted alkenyl group, an optionally substituted alkynyl group, an optionally substituted alkoxy group, an optionally substituted aromatic hydrocarbon ring group, or an optionally substituted aromatic heterocyclic group, and two or more of R1 to R5 may be bonded to form a ring, with the proviso that none of R1 to R5 is a hydrogen atom.)

[0009] [2] The purification method according to [1] above preferably further comprises a step of purifying the object to be treated by recrystallization before carrying out purification using the adsorbent.

[0010] [3] The purification method according to [2] above preferably further comprises a step of purifying the object to be treated, which has been purified using the adsorbent, by recrystallization.

[0011] [4] In any of the purification methods [1] to [3] above, the adsorbent is preferably at least one selected from the group consisting of activated clay, silica gel, activated alumina, and activated carbon.

[0012] Another object of the present invention is to advantageously solve the above-mentioned problems, and the present invention relates to [5] a monomer composition containing a norbornene imide monomer represented by the following formula (1), which has a transmittance of 90% or more for light having a wavelength of 550 nm: [ka] (In formula (1), R1 to R5 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted alkenyl group, an optionally substituted alkynyl group, an optionally substituted alkoxy group, an optionally substituted aromatic hydrocarbon ring group, or an optionally substituted aromatic heterocyclic group, and two or more of R1 to R5 may be bonded to form a ring, with the proviso that none of R1 to R5 is a hydrogen atom.) In the present invention, the "transmittance to light with a wavelength of 550 nm" can be measured by the method described in the examples.

[0013] Another object of the present invention is to advantageously solve the above-mentioned problems, and the present invention relates to [6] a polymer composition comprising a cyclic olefin ring-opening polymer having a structural unit derived from a norbornene imide monomer represented by the following formula (1), wherein the polymer composition has a transmittance of 90% or more for light having a wavelength of 550 nm: [ka] (In formula (1), R1 to R5 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted alkenyl group, an optionally substituted alkynyl group, an optionally substituted alkoxy group, an optionally substituted aromatic hydrocarbon ring group, or an optionally substituted aromatic heterocyclic group, and two or more of R1 to R5 may be bonded to form a ring, with the proviso that none of R1 to R5 is a hydrogen atom.)

[0014] Another object of the present invention is to advantageously solve the above-mentioned problems, and the present invention relates to [7] a resin composition containing the monomer composition of [5] above.

[0015] Another object of the present invention is to advantageously solve the above-mentioned problems, and the present invention relates to [8] a resin composition containing the polymer composition described in [6] above.

[0016] Another object of the present invention is to advantageously solve the above-mentioned problems, and the present invention is [9] a resin molded body obtained by molding the resin composition described in [8] above.

[0017] Another object of the present invention is to advantageously solve the above-mentioned problems, and the present invention relates to

[10] a method for producing a resin molded product, comprising a step of molding a resin composition containing a cyclic olefin ring-opening polymer, wherein the cyclic olefin ring-opening polymer contains structural units derived from the norbornene imide monomer represented by formula (1) obtained by any of the purification methods [1] to [4] above.

[0018] Another object of the present invention is to advantageously solve the above-mentioned problems, and the present invention is a method for producing a resin molded product, comprising the step of molding a resin composition containing a cyclic olefin ring-opening polymer, wherein the cyclic olefin ring-opening polymer is a cyclic olefin ring-opening polymer obtained by any one of the purification methods [1] to [4] above. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a method for purifying a treatment target containing a norbornene imide monomer or a cyclic olefin ring-opening polymer containing a structural unit derived from a norbornene imide monomer. Furthermore, according to the present invention, it is possible to provide a monomer composition containing the norbornene imide monomer in which coloration is sufficiently suppressed, and a polymer composition containing the cyclic olefin ring-opening polymer in which coloration is sufficiently suppressed. Another object of the present invention is to provide a resin composition that can be advantageously used as a material for various molded articles such as optical elements, a resin molded article formed using the resin composition, and a method for producing the resin molded article. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described in detail. The purification method of the present invention can be suitably used, for example, in preparing the monomer composition and polymer composition of the present invention. Furthermore, the monomer composition of the present invention can be suitably used, for example, in preparing the polymer composition of the present invention. Furthermore, the polymer composition of the present invention can be suitably used, for example, in preparing the resin composition of the present invention. Furthermore, the resin composition of the present invention can be suitably used, for example, as a material for producing the resin molded article of the present invention. The resin molded article of the present invention can be suitably used, for example, as an optical element such as an optical film, a lens for a photographing device such as a camera, or a lens for a mobile terminal such as a mobile phone or a smartphone. Furthermore, the method for producing a resin molded article of the present invention can be suitably used, for example, in producing the resin molded article of the present invention.

[0021] (purification method) The purification method of the present invention includes a step (preparation step) of preparing a treatment object containing a norbornene imide monomer represented by the following formula (1) or a cyclic olefin ring-opening polymer containing a structural unit derived from the norbornene imide monomer represented by the following formula (1) (hereinafter, also simply referred to as a "cyclic olefin ring-opening polymer"), and a step (purification step) of purifying the treatment object using an adsorbent, and optionally further includes other steps such as a recrystallization step. [ka] (In formula (1), R1 to R5 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted alkenyl group, an optionally substituted alkynyl group, an optionally substituted alkoxy group, an optionally substituted aromatic hydrocarbon ring group, or an optionally substituted aromatic heterocyclic group, and two or more of R1 to R5 may be bonded to form a ring, with the proviso that none of R1 to R5 is a hydrogen atom.)

[0022] <Preparation process> In the preparation step, a treatment object is prepared that contains a norbornene imide monomer represented by formula (1) or a cyclic olefin ring-opening polymer that contains a structural unit derived from the norbornene imide monomer represented by formula (1). Here, the norbornene imide monomer and the cyclic olefin ring-opening polymer may be synthesized or commercially available.

[0023] <<Objects to be processed>> The object to be treated includes the norbornene imide monomer or cyclic olefin ring-opening polymer and may further include, optionally, components such as a solvent and reagents used in the synthesis. The solvent is not particularly limited and may be, for example, a solvent used in the synthesis or hydrogenation (described below) or a solvent used in the purification step or recrystallization step (described below). Specifically, for example, the reaction solution containing the norbornene imide monomer or cyclic olefin ring-opening polymer synthesized in the preparation step may be used as the object to be treated as is. Alternatively, the norbornene imide monomer or cyclic olefin ring-opening polymer may be isolated from the reaction solution, dried, and then dissolved in a solvent. Alternatively, the object to be treated may be a commercially available norbornene imide monomer or cyclic olefin ring-opening polymer dissolved in a solvent.

[0024] <<Norbornene imide monomer>> The norbornene imide monomer used in the present invention is a compound represented by the following formula (1). [ka] (In formula (1), R1 to R5 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted alkenyl group, an optionally substituted alkynyl group, an optionally substituted alkoxy group, an optionally substituted aromatic hydrocarbon ring group, or an optionally substituted aromatic heterocyclic group, and two or more of R1 to R5 may be bonded to form a ring, with the proviso that none of R1 to R5 is a hydrogen atom.)

[0025] Here, the halogen atoms that can constitute R1 to R5 are not particularly limited, and examples thereof include a chlorine atom, a fluorine atom, a bromine atom, and an iodine atom.

[0026] The alkyl group which may have a substituent and which may constitute R1 to R5 is not particularly limited, and examples thereof include alkyl groups having 1 to 10 carbon atoms which may have a substituent. The alkyl group having 1 to 10 carbon atoms in the "alkyl group having 1 to 10 carbon atoms which may have a substituent" may be either linear or branched, and examples thereof include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, neopentyl group, hexyl group, octyl group, nonyl group, and decyl group. Of these, a methyl group is preferred. Specific examples of the substituent of the "alkyl group having from 1 to 10 carbon atoms which may have a substituent" include, for example, a halogen atom such as a chlorine atom, a fluorine atom, a bromine atom, or an iodine atom; a cyano group; a nitro group; an unsubstituted alkyl group having from 1 to 10 carbon atoms such as a methyl group, an ethyl group, or a propyl group; an unsubstituted alkenyl group having from 2 to 6 carbon atoms such as a vinyl group or an allyl group; an alkyl group having from 1 to 10 carbon atoms in which one or more hydrogen atoms are substituted with a halogen atom such as a fluorine atom, such as a trifluoromethyl group; and an alkoxy group having from 1 to 10 carbon atoms such as a methoxy group, an ethoxy group, or an isopropoxy group. The number of substituents may be one or more. When multiple substituents are present, they may be the same or different.

[0027] The cycloalkyl group which may have a substituent and which may constitute R1 to R5 is not particularly limited, and examples thereof include a cycloalkyl group having from 3 to 12 carbon atoms which may have a substituent. Examples of the cycloalkyl group having from 3 to 12 carbon atoms in the "cycloalkyl group having from 3 to 12 carbon atoms which may have a substituent" include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. Specific examples of the substituent of the "cycloalkyl group having from 3 to 12 carbon atoms, which may have a substituent" include the same as the substituent that may be possessed by the above-mentioned "alkyl group having from 1 to 10 carbon atoms, which may have a substituent." The number of substituents may be one or more. When multiple substituents are possessed, they may be the same as or different from each other.

[0028] The alkenyl group which may have a substituent and which can constitute R1 to R5 is not particularly limited, and examples thereof include alkenyl groups having from 2 to 10 carbon atoms which may have a substituent. The alkenyl group having from 2 to 10 carbon atoms in the "alkenyl group having from 2 to 10 carbon atoms which may have a substituent" may be either linear or branched, and examples thereof include a vinyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, and a decenyl group. Specific examples of the substituent of the "alkenyl group having from 2 to 10 carbon atoms, which may have a substituent," include the same substituents as those that may be possessed by the above-mentioned "alkyl group having from 1 to 10 carbon atoms, which may have a substituent." The number of substituents may be one or more. When multiple substituents are possessed, they may be the same as or different from each other.

[0029] The alkynyl group which may have a substituent and which may constitute R1 to R5 is not particularly limited, and examples thereof include an alkynyl group having from 2 to 10 carbon atoms which may have a substituent. The alkynyl group having from 2 to 10 carbon atoms in the "alkynyl group having from 2 to 10 carbon atoms which may have a substituent" may be either linear or branched, and examples thereof include an ethynyl group, a propynyl group, a 2-propynyl group (propargyl group), a butynyl group, a 2-butynyl group, a 3-butynyl group, a pentynyl group, a 2-pentynyl group, a hexynyl group, a 5-hexynyl group, a heptynyl group, an octynyl group, a 2-octynyl group, a nonanyl group, a decanyl group, and a 7-decanyl group. Specific examples of the substituent of the "alkynyl group having from 2 to 10 carbon atoms, which may have a substituent" include the same as the substituent that may be possessed by the above-mentioned "alkyl group having from 1 to 10 carbon atoms, which may have a substituent." The number of substituents may be one or more. When multiple substituents are possessed, they may be the same as or different from each other.

[0030] The alkoxy group which may have a substituent and which can constitute R1 to R5 is not particularly limited, and examples thereof include an alkoxy group having from 1 to 10 carbon atoms which may have a substituent. The alkoxy group having from 1 to 10 carbon atoms in the "alkoxy group having from 1 to 10 carbon atoms which may have a substituent" may be either linear or branched, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, and an octoxy group. Specific examples of the substituent of the "alkoxy group having from 1 to 10 carbon atoms, which may have a substituent" include the same as the substituent that may be possessed by the above-mentioned "alkyl group having from 1 to 10 carbon atoms, which may have a substituent." The number of substituents may be one or more. When multiple substituents are possessed, they may be the same as or different from each other.

[0031] The aromatic hydrocarbon ring group which may have a substituent and which can constitute R1 to R5 is not particularly limited, and examples thereof include aromatic hydrocarbon ring groups having from 6 to 30 carbon atoms which may have a substituent. Examples of the aromatic hydrocarbon ring group having from 6 to 30 carbon atoms which is an "aromatic hydrocarbon ring group having from 6 to 30 carbon atoms which may have a substituent" include a phenyl group, a naphthyl group, an anthracenyl group, etc. Specific examples of the substituent of the "optionally substituted aromatic hydrocarbon ring group having from 6 to 30 carbon atoms" include the same as the substituents that may be possessed by the above-mentioned "optionally substituted alkyl group having from 1 to 10 carbon atoms." The number of substituents may be one or more. When multiple substituents are possessed, they may be the same or different.

[0032] The aromatic heterocyclic group which may have a substituent and which can constitute R1 to R5 is not particularly limited, and examples thereof include aromatic heterocyclic groups having from 6 to 30 carbon atoms which may have a substituent. Examples of the aromatic hydrocarbon ring group having from 6 to 30 carbon atoms in the "aromatic heterocyclic group which may have a substituent" include a furanyl group, a 1-benzofuranyl group, a 2-benzofuranyl group, a pyrrolyl group, an indolyl group, a thienyl group, a benzo[c]thienyl group, a benzo[b]thienyl group, a pyridyl group, a pyrazinyl group, a pyrimidinyl group, a triazolyl group, a triazinyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, a benzothiazolyl group, an oxazolyl group, and a benzoxazolyl group. Specific examples of the substituent of the "aromatic heterocyclic group having from 6 to 30 carbon atoms, which may have a substituent," include the same as the substituent that may be possessed by the above-mentioned "alkyl group having from 1 to 10 carbon atoms, which may have a substituent." The number of substituents may be one or more. When multiple substituents are possessed, they may be the same as or different from each other.

[0033] The ring formed by combining two or more of R1 to R5 may be a monocyclic ring or a polycyclic ring. The ring formed by combining two or more of R1 to R5 is not particularly limited, and examples thereof include an aromatic hydrocarbon ring, an aromatic heterocyclic ring, a non-aromatic hydrocarbon ring, and a polycyclic fused ring formed by condensing two or more of these rings. Specific examples of the aromatic hydrocarbon ring include, but are not limited to, aromatic hydrocarbon rings having 6 to 30 carbon atoms such as a benzene ring, a naphthalene ring, an anthracene ring, etc. Of these, a benzene ring is preferred. Furthermore, the aromatic heterocycle is not particularly limited, and examples thereof include aromatic heterocycles having 2 to 30 carbon atoms such as a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, an imidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, and a benzoxazole ring. Specific examples of non-aromatic hydrocarbon rings include cycloalkyl rings having 3 to 12 carbon atoms, such as a cyclopropyl ring, a cyclobutyl ring, a cyclopentyl ring, a cyclohexyl ring, and a cyclooctyl ring.

[0034] Among these, from the viewpoint of further reducing the birefringence while imparting an appropriate Abbe number to the resulting hydrogenated cyclic olefin ring-opening polymer, the norbornene imide monomer represented by formula (1) is preferably a compound in which one or more of R1 to R5 in formula (1) are "an alkyl group having from 1 to 10 carbon atoms which may have a substituent" and the remainder are hydrogen atoms, and more preferably a compound in which two of R1 to R5 are "an alkyl group having from 1 to 10 carbon atoms which may have a substituent" and the remainder are hydrogen atoms. From the viewpoint of further reducing the birefringence while imparting an appropriate Abbe number to the resulting hydrogenated cyclic olefin ring-opening polymer, the norbornene imide monomer represented by formula (1) is preferably a compound in which at least one of R1 to R5 in formula (1) is a methyl group or an isopropyl group, and the remainder is a hydrogen atom, and more preferably a compound in which two of R1 to R5 in formula (1) are methyl groups or isopropyl groups, and the remainder is a hydrogen atom. Among these, compounds in which at least one of R1 and R5 in formula (1) is a methyl group or an isopropyl group, and the remainder is a hydrogen atom (N-2-methylphenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, N-2-isopropylphenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide) are preferred, and compounds in which R1 and R5 in formula (1) are methyl groups or isopropyl groups, and the remainder is a hydrogen atom (i.e., N N-2,6-dimethylphenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, N-2,6-diisopropylphenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide) are more preferred, and a compound in which R and R in formula (1) are isopropyl groups and the remainder are hydrogen atoms (i.e., N-2,6-diisopropylphenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide) is even more preferred.

[0035] As described above, in formula (1), none of R1 to R5 is a hydrogen atom. While norbornene imide monomers other than the norbornene imide monomer represented by formula (1), such as "N-phenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide," a compound in which all of R1 to R5 in formula (1) are hydrogen atoms, do not suffer from coloration problems, norbornene imide monomers represented by formula (1) in which none of R1 to R5 is a hydrogen atom will color and therefore require purification.

[0036] [Manufacturing method] The norbornene imide monomer represented by formula (1) is not particularly limited, and can be produced, for example, by reacting 5-norbornene-2,3-dicarboxylic anhydride represented by the following formula (1-1) with a substituted aniline represented by the following formula (1-2). [ka] [ka] (In formula (1-2), the definitions of R1 to R5 are the same as those in formula (1).)

[0037] The reaction time is not particularly limited and can usually be 3 hours or more and 48 hours or less, and the reaction temperature is not particularly limited and can usually be 90°C or more and 160°C or less.

[0038] <<Cyclic olefin ring-opening polymer>> A cyclic olefin ring-opening polymer can be obtained, for example, by ring-opening polymerization of a monomer composition containing a cyclic olefin compound (monomer) including a norbornene imide monomer in the presence of a polymerization catalyst, and optionally hydrogenating the resulting cyclic olefin ring-opening polymer. In the present invention, the term "cyclic olefin ring-opening polymer" encompasses both a cyclic olefin ring-opening polymer (unhydrogenated cyclic olefin ring-opening polymer) obtained by ring-opening polymerization of a monomer composition containing a cyclic olefin compound, and a hydrogenated cyclic olefin ring-opening polymer obtained by hydrogenating the cyclic olefin ring-opening polymer. In the present invention, a cyclic olefin ring-opening polymer obtained by hydrogenating an unhydrogenated cyclic olefin ring-opening polymer may also be referred to as a "hydrogenated cyclic olefin ring-opening polymer." The cyclic olefin ring-opening polymer contains structural units derived from norbornene imide monomers, and optionally further contains other structural units.

[0039] [Structural units derived from norbornene imide monomers] The structural unit derived from the norbornene imide monomer contained in the cyclic olefin ring-opening polymer is a structural unit obtained by polymerizing the norbornene imide monomer represented by formula (1) described above in the section "Norbornene Imide Monomer" (a structural unit (unhydrogenated structural unit) obtained by ring-opening polymerization of the norbornene imide monomer, or a structural unit obtained by hydrogenating the structural unit). From the viewpoint of further reducing the birefringence while imparting an appropriate Abbe number to the cyclic olefin ring-opening polymer, the norbornene imide monomer represented by formula (1) is preferably a compound in which one or more of R1 to R5 in formula (1) are "optionally substituted alkyl groups having 1 to 10 carbon atoms" and the remainder are hydrogen atoms, and more preferably a compound in which two of R1 to R5 are "optionally substituted alkyl groups having 1 to 10 carbon atoms" and the remainder are hydrogen atoms. From the viewpoint of further reducing the birefringence while imparting an appropriate Abbe number to the cyclic olefin ring-opening polymer, the norbornene imide monomer represented by formula (1) is preferably a compound in which at least one of R1 to R5 in formula (1) is a methyl group or an isopropyl group, and the remaining is a hydrogen atom, and more preferably a compound in which two of R1 to R5 in formula (1) are methyl groups or isopropyl groups, and the remaining is a hydrogen atom. Among these, compounds in which at least one of R1 and R5 in formula (1) is not a hydrogen atom, and compounds in which at least one of R1 and R5 in formula (1) is a methyl group or an isopropyl group, and the remaining is a hydrogen atom (i.e., N-2-methylphenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, N-2-isopropylphenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide) are preferred, and compounds in which R1 and R5 in formula (1) are methyl groups or isopropyl groups, and the remaining is a hydrogen atom are more preferred. Compounds in which R and R in formula (1) are hydrogen atoms (i.e., N-2,6-dimethylphenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, N-2,6-diisopropylphenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide) are more preferred, and compounds in which R and R in formula (1) are isopropyl groups and the remainder are hydrogen atoms (i.e., N-2,6-diisopropylphenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide) are even more preferred.

[0040] -Content ratio- The content of the structural unit derived from the norbornene imide monomer represented by formula (1) (the total content of the structural unit obtained by ring-opening polymerization of the norbornene imide monomer and the structural unit obtained by hydrogenating the structural unit; the same applies hereinafter) is preferably 10% by mass or more, more preferably 25% by mass or more, even more preferably 40% by mass or more, particularly preferably 50% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less, when the content of all repeating units contained in the cyclic olefin ring-opening polymer is taken as 100% by mass. If the content of the structural unit derived from the norbornene imide monomer represented by formula (1) is within the above-mentioned specified range, the birefringence can be further reduced while maintaining an appropriate Abbe number of the cyclic olefin ring-opening polymer.

[0041] Other structural units The other structural units in the cyclic olefin ring-opening polymer are structural units obtained by polymerizing a cyclic olefin compound capable of forming the other structural units (structural units (unhydrogenated structural units) obtained by ring-opening polymerization of a cyclic olefin compound capable of forming the other structural units, or structural units obtained by hydrogenating such structural units). The structural units obtained by polymerizing a cyclic olefin compound capable of forming the other structural units are not particularly limited as long as they are not structural units obtained by polymerizing a norbornene imide monomer represented by the above-mentioned formula (1), and examples thereof include structural units obtained by polymerizing a cyclic olefin monomer not having a polar group. The "cyclic olefin monomer that does not have polar group" that can form the structural unit that is polymerized with the cyclic olefin monomer that does not have polar group is not particularly limited, as long as it has one or more ethylenic unsaturated bonds that can be ring-opening polymerized and does not have polar group, for example, can be enumerated as the norbornene compound that does not have polar group and the non-norbornene compound that does not have polar group.These can be used in combination, but from the viewpoint of further reducing birefringence while giving cyclic olefin ring-opening polymer a moderate Abbe number, the "cyclic olefin monomer that does not have polar group" that can form the structural unit that is polymerized with the cyclic olefin monomer that does not have polar group is preferably the norbornene compound that does not have polar group.

[0042] -Norbornene compounds without polar groups- The norbornene compound having no polar group is not particularly limited as long as it is a non-polar compound having one or more norbornene rings, and examples thereof include: Bicyclic norbornene compounds such as bicyclo[2.2.1]hept-2-ene (trivial name: norbornene), 5-ethylidene-2-norbornene (trivial name: ethylidenenorbornene) and their derivatives; Tricyclo[4.3.0.1 2,5 ] Tricyclic norbornene compounds such as deca-3,7-diene (common name: dicyclopentadiene) and its derivatives; 7,8-benzotricyclo[4.3.0.1 2,5 ]dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo[4.4.0.1 2,5 .1 7,10 ] Tetracyclic norbornene compounds such as dodec-3-ene (trivial name: tetracyclododecene), 2-ethylidene-1,2,3,4,4a,5,8,8a-octahydro-1,4:5,8-dimethanonaphthalene (trivial name: ethylidenetetracyclododecene) and their derivatives; 7,8-benzotricyclo[4.3.0.1 2,5 ]dec-3-ene (common name: methanotetrahydrofluorene, tetracyclo[7.4.0.0 2,7 .1 10,13]trideca-2,4,6,11-tetraene), tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodec-3-ene (common name: tetracyclododecene), 8-ethylidenetetracyclo[4.4.0.1 2,5 .1 7,10 tetracyclic norbornene compounds such as ]-3-dodecene and derivatives thereof; and Norbornene compounds with five or more rings, such as pentacyclo[6.5.1.13,6.02,7.09,13]pentadeca-4,10-diene, pentacyclo[9.2.1.14,7.02,10.03,8]pentadeca-5,12-diene, hexacyclo[6.6.1.13,6.110,13.02,7.09,14]heptadeca-4-ene, 1,2,3,3a,4,6a-hexahydro-1,2,4-methenopentalene (common name: deltacyclene) and derivatives thereof; Here, the derivative refers to a compound having a substituent in a ring structure. The substituent that can be contained in the ring structure is not particularly limited as long as it is not a polar group, and examples thereof include hydrocarbon groups such as alkyl groups, alkylene groups, alkylidene groups, aryl groups, and vinyl groups. The ring structure of the derivative may have one or more of these substituents.

[0043] Among these, from the viewpoint of further reducing the birefringence while imparting an appropriate Abbe number to the cyclic olefin ring-opening polymer, ethylidenetetracyclododecene or deltacyclene is preferred as the norbornene compound having no polar group, and deltacyclene is more preferred. In other words, the structural unit derived from a cyclic olefin monomer having no polar group preferably includes a structural unit derived from ethylidenetetracyclododecene or deltacyclene, more preferably includes a structural unit derived from deltacyclene, and even more preferably is a structural unit derived from deltacyclene. Deltacyclene is a compound represented by the following formula (2). [ka]

[0044] These norbornene compounds having no polar group may be used alone or in combination of two or more.

[0045] -Non-norbornene compounds without polar groups- The non-norbornene compound having no polar group is not particularly limited as long as it does not have a polar group or a norbornene ring, and examples thereof include monocyclic cycloalkenes such as cyclobutene, cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2-(2-methylbutyl)-1-cyclohexene, cyclooctene, 3a,5,6,7a-tetrahydro-4,7-methano-1H-indene, and cycloheptene, and derivatives thereof. Here, the derivative refers to a compound having a substituent in a ring structure. The substituent that can be contained in the ring structure is not particularly limited as long as it is not a polar group, and the same substituents as those described above in the section "Norbornene Compounds Having No Polar Groups" can be used. The ring structure of the derivative may have one or more of these substituents.

[0046] The non-norbornene compounds having no polar group described above may be used singly or in combination of two or more.

[0047] -Content ratio- The content of other structural units (the total content of structural units (unhydrogenated structural units) obtained by ring-opening polymerization of cyclic olefin compounds capable of forming such structural units and structural units obtained by hydrogenating such structural units; the same applies hereinafter) is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, and is preferably 90% by mass or less, more preferably 75% by mass or less, and even more preferably 60% by mass or less, when the content of all repeating units contained in the cyclic olefin ring-opening polymer is taken as 100% by mass. When the content of other structural units is equal to or greater than the above-mentioned lower limit, precipitation of the cyclic olefin ring-opening polymer after synthesis can be suppressed. Furthermore, when the content of other structural units is equal to or greater than the above-mentioned lower limit, the glass transition temperature of the cyclic olefin ring-opening polymer can be suppressed from becoming too high. Note that when the content of other structural units is equal to or less than the above-mentioned upper limit, precipitation of the cyclic olefin ring-opening polymer after synthesis and thermal deformation of a molded product due to a low glass transition temperature of the cyclic olefin ring-opening polymer can be suppressed.

[0048] -Method of manufacturing a cyclic olefin ring-opening polymer- The cyclic olefin ring-opening polymer can be obtained by ring-opening polymerization of a monomer composition (mixture) containing the various monomers described above in the section "Cyclic olefin ring-opening polymer," and optionally hydrogenating the resulting cyclic olefin ring-opening polymer. Specifically, for example, the cyclic olefin ring-opening polymer can be prepared by ring-opening polymerization of the above-mentioned monomer composition using a known ring-opening polymerization method such as ring-opening polymerization using a metathesis polymerization catalyst, and optionally hydrogenating the resulting cyclic olefin ring-opening polymer. By carrying out ring-opening polymerization, the number of rings possessed by each of the above-mentioned monomers is reduced by at least one.

[0049] The metathesis polymerization catalyst is not particularly limited, and known catalysts can be used. Specifically, for example, a catalyst system consisting of a halide, nitrate, or acetylacetone compound of a metal selected from ruthenium, rhodium, palladium, osmium, iridium, and platinum, and a reducing agent; a catalyst system consisting of a halide or acetylacetone compound of a metal selected from titanium, vanadium, zirconium, tungsten, and molybdenum, and an organoaluminum compound as a co-catalyst; or known Schrock-type or Grubbs-type living ring-opening metathesis catalysts, as disclosed in JP-A-7-179575, J. Am. Chem. Soc., 1986, 108, 733, J. Am. Chem. Soc., 1993, 115, 9858, and J. Am. Chem. Soc., 1996, 118, 100, etc., can be used. These catalysts can be used alone or in combination of two or more. The amount of the catalyst used may be appropriately selected depending on the polymerization conditions and the like.

[0050] A polar compound can be further added to the catalyst system to enhance polymerization activity and ring-opening polymerization selectivity. Examples of polar compounds include molecular oxygen, alcohols, ethers, peroxides, carboxylic acids, acid anhydrides, acid chlorides, esters, ketones, nitrogen-containing compounds, sulfur-containing compounds, halogen-containing compounds, molecular iodine, and other Lewis acids. Preferred nitrogen-containing compounds are aliphatic or aromatic tertiary amines, and specific examples include triethylamine, dimethylaniline, tri-n-butylamine, pyridine, and α-picoline. These polar compounds can be used alone or in combination of two or more. The amount of polar compound used can be appropriately selected, but the ratio to the metal in the catalyst, i.e., the polar compound / metal ratio (molar ratio), is typically in the range of 1 to 100,000, preferably 5 to 10,000.

[0051] The polymerization reaction may be carried out by bulk polymerization without using a solvent, or may be carried out in a solvent such as an organic solvent. The solvent is not particularly limited as long as it is inert to the polymerization reaction, and examples thereof include aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as n-pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclohexane; halogenated hydrocarbons such as styrene dichloride, dichloroethane, dichloroethylene, tetrachloroethane, chlorobenzene, dichlorobenzene, and trichlorobenzene; nitrogen-containing hydrocarbons such as nitromethane, nitrobenzene, acetonitrile, and benzonitrile; and ether solvents such as tetrahydrofuran and ethylene glycol dimethyl ether.

[0052] The polymerization conditions such as polymerization temperature, polymerization pressure, and polymerization time can be adjusted appropriately.

[0053] --Hydrogenation-- The hydrogenation of a cyclic olefin ring-opening polymer obtained by ring-opening polymerization of a monomer composition containing the norbornene imide monomer represented by the above formula (1) can be carried out using hydrogen and a hydrogenation catalyst. The hydrogenation of a cyclic olefin ring-opening polymer can be carried out using any hydrogenation catalyst and hydrogenation conditions as long as the non-aromatic carbon-carbon unsaturated bonds, such as olefinic double bonds, present in the cyclic olefin ring-opening polymer can be hydrogenated.

[0054] The hydrogenation of a cyclic olefin ring-opening polymer is carried out so that the hydrogenation rate of non-aromatic carbon-carbon unsaturated bonds such as olefinic double bonds present in the cyclic olefin ring-opening polymer (the proportion of hydrogenated non-aromatic carbon-carbon unsaturated bonds in the cyclic olefin ring-opening polymer) is typically 90% or more, preferably 95% or more, and more preferably 99% or more. If the hydrogenation rate of non-aromatic carbon-carbon unsaturated bonds such as olefinic double bonds contained in the cyclic olefin ring-opening polymer is equal to or higher than the above-mentioned lower limit, yellowing due to oxidative degradation of the resin during molding, etc. can be suppressed.

[0055] The carbon-carbon unsaturated bonds (aromatic carbon-carbon unsaturated bonds) of the aromatic ring structures (aromatic rings and / or aromatic heterocycles) present in the hydrogenated cyclic olefin ring-opening polymer may be hydrogenated, but from the viewpoint of further reducing the birefringence while maintaining an appropriate Abbe number, it is preferable that they are not hydrogenated. Specifically, the hydrogenation rate of the aromatic carbon-carbon unsaturated bonds in the hydrogenated cyclic olefin ring-opening polymer (the proportion of hydrogenated aromatic carbon-carbon unsaturated bonds in the cyclic olefin ring-opening polymer) is preferably 20% or less, more preferably 10% or less, and particularly preferably 0% (i.e., not hydrogenated). In the present invention, the hydrogenation rates of non-aromatic carbon-carbon unsaturated bonds and aromatic carbon-carbon unsaturated bonds can be measured by the method described in the Examples. Furthermore, the hydrogenation rates of non-aromatic carbon-carbon unsaturated bonds and aromatic carbon-carbon unsaturated bonds can be adjusted by, for example, changing the type and amount of the hydrogenation catalyst and / or the conditions of the hydrogenation reaction (such as the reaction temperature).

[0056] Examples of usable hydrogenation catalysts include hydrogenation catalysts composed of dicyclopentadienyl titanium halide, organic nickel carboxylate, organic cobalt carboxylate, or the like, and an organometallic compound of Groups 1 to 3 of the periodic table; metal catalysts such as nickel, platinum, palladium, ruthenium, rhenium, or rhodium supported on carbon, silica, diatomaceous earth, or the like, and cobalt, nickel, rhodium, or ruthenium complexes; and hydrogenated compounds such as lithium aluminum hydride and p-toluenesulfonyl hydrazide. Among these, ruthenium compounds are preferred as hydrogenation catalysts, from the viewpoint of obtaining the target product in good yield without isomerization.

[0057] Examples of ruthenium compounds include RuHCl(CO)(PPh3)3, RuHCl(CO)[P(p-Me-Ph)3]3, RuHCl(CO)(PCy3)2, RuHCl(CO)[P(n-Bu)3]3, RuHCl(CO)[P(i-Pr)3]2, RuH2(CO)(PPh3)3, RuH2(CO)[P(p-Me-Ph)3]3, RuH2(CO)(PCy3)3, RuH2(CO)[P(n-Bu)3]3, RuH(OCOCH3)(CO)(PPh3)2, RuH(OCOPh)(CO)(PPh3)2, RuH(OCOPh-CH3)(CO)(PPh3)2, RuH(OCOPh-OCH3)(CO)(PPh3)2, RuH(OCOPh)(CO)(PCy3)2, and the like.

[0058] The hydrogenation reaction of the cyclic olefin ring-opening polymer can usually be carried out in an inert organic solvent, such as aromatic hydrocarbon solvents such as benzene, toluene, and xylene; aliphatic hydrocarbon solvents such as pentane and hexane; alicyclic hydrocarbon solvents such as cyclohexane and decahydronaphthalene; and ether solvents such as tetrahydrofuran and ethylene glycol dimethyl ether.

[0059] The reaction temperature when hydrogen is added to a system containing a cyclic olefin ring-opening polymer and a hydrogenation catalyst to hydrogenate the cyclic olefin ring-opening polymer varies depending on the hydrogenation catalyst used, but is usually −20° C. to 250° C., preferably −10° C. to 220° C., and more preferably 0° C. to 200° C. If the reaction temperature is too low, the hydrogenation rate may be too slow, and if the reaction temperature is too high, side reactions may occur. The hydrogen pressure is usually 0.01 to 20 MPa, preferably 0.05 to 15 MPa, and more preferably 0.1 to 10 MPa. If the hydrogen pressure is too low, the hydrogenation rate may be too slow, whereas if it is too high, a high-pressure reactor is required, which imposes restrictions on the apparatus. Furthermore, the reaction time varies depending on the reaction scale, but is usually 0.1 to 10 hours.

[0060] <Purification process> In the purification step, the treatment target material containing the norbornene imide monomer represented by formula (1) or a cyclic olefin ring-opening polymer containing a structural unit derived from the norbornene imide monomer represented by formula (1), obtained in the above-mentioned preparation step, is purified using an adsorbent.

[0061] The purification using an adsorbent is not particularly limited, and examples thereof include purification by column chromatography using an adsorbent in a column, purification by filtration using an adsorbent, etc. Among these, purification by filtration using an adsorbent is preferred from the viewpoint of effectively removing impurities that cause coloration and suppressing coloration. Here, in purification by filtration using an adsorbent, an adsorbent and, optionally, a solvent are added to the material to be treated, and the resulting solution is filtered. Among these, it is preferred to add an adsorbent and a solvent to the material to be treated and then filter the resulting solution.

[0062] The adsorbent is not particularly limited, and examples thereof include activated clay, silica gel, activated alumina, and activated carbon. These adsorbents may be used alone or in combination of two or more. Among them, at least one selected from the group consisting of silica gel, activated alumina, and activated carbon is preferred. The amount of adsorbent used is not particularly limited, but is preferably 20% by mass or more, more preferably 25% by mass or more, and preferably 30% by mass or less, based on the norbornene imide monomer or cyclic olefin ring-opening polymer represented by formula (1).

[0063] The solvent used for purification is not particularly limited, and organic solvents such as hydrocarbons such as heptane and toluene, ethers such as methyl tert-butyl ether, nitriles such as acetonitrile, ketones such as acetone and methyl ethyl ketone, and esters such as ethyl acetate can be used. Two or more of these solvents can be used in combination. Among them, toluene and methyl ethyl ketone are preferred as the solvent, and a mixed solvent of toluene and heptane, or a mixed solvent of methyl ethyl ketone and heptane is more preferred. The concentration of the solvent in the object to be treated is not particularly limited, but is more preferably 5% by mass or more, more preferably 10% by mass or more, and is preferably 15% by mass or less.

[0064] The purification temperature is not particularly limited, but it is preferable to perform the purification at room temperature. The purification time (time of contact with the adsorbent) is not particularly limited, but it is preferably 3 hours or more.

[0065] According to the investigations of the present inventors, the impurities that cause coloration cannot be removed by other purification methods such as recrystallization that do not use an adsorbent, but can be removed well by purification that uses an adsorbent.

[0066] <Other processes> The other steps are not particularly limited, and examples thereof include a recrystallization step and a drying step. In particular, the purification method of the present invention preferably includes a recrystallization step. The recrystallization step may be performed on the treatment object before the purification step or on the treatment object after the purification step, but from the viewpoints of suppressing a decrease in the lifespan of the adsorbent by removing impurities other than those that cause coloration and efficiently removing impurities that cause coloration in the adsorbent, the recrystallization step is preferably performed at least before the purification step, and is preferably performed both before and after the purification step.

[0067] <<Recrystallization process>> In the recrystallization step, the object to be treated is purified by recrystallization. The recrystallization method is not particularly limited and can be performed by a conventionally known method. Specifically, recrystallization can be performed, for example, by heating the object to be treated (solution) containing the norbornene imide monomer represented by formula (1) or the cyclic olefin ring-opening polymer and a solvent to 70°C to dissolve the solution, and then cooling it to 0°C to precipitate crystals of the norbornene imide monomer represented by formula (1) or the cyclic olefin ring-opening polymer, and then separating the resulting crystals. The solvent used for recrystallization is not particularly limited, and for example, the solvents mentioned above in the "purification step" section can be used.

[0068] <<Drying process>> In the drying step, the treated object is dried to remove the solvent. The drying method is not particularly limited, and a conventionally known method can be used. Drying may be carried out after the purification step, after the recrystallization step, or after both the purification step and the recrystallization step.

[0069] The treated material obtained through such a purification step and any other steps can be used as it is as the monomer composition or polymer composition of the present invention.

[0070] (Monomer Composition) The monomer composition of the present invention contains the norbornene imide monomer represented by the above formula (1), and optionally further contains a solvent. The monomer composition of the present invention is characterized by having a transmittance of 90% or more for light having a wavelength of 550 nm. Therefore, the monomer composition of the present invention has a small amount of impurities and is sufficiently suppressed from coloring. Therefore, the monomer composition of the present invention can be suitably used for producing polymer compositions and resin compositions useful as materials for various molded articles such as optical elements. The monomer composition of the present invention preferably has a transmittance of 95% or more, more preferably 98% or more, to light with a wavelength of 550 nm.

[0071] <Solvent> The solvent optionally contained in the monomer composition of the present invention is not particularly limited, and water or the same organic solvent as described above in the section "Purification method of the present invention" can be used.

[0072] <Norbornene imide monomer content> The content of the norbornene imide monomer represented by formula (1) in the monomer composition of the present invention is preferably 50% by mass or more, more preferably 70% by mass or more.

[0073] The monomer composition of the present invention can be suitably obtained by purifying a treatment target containing a norbornene imide monomer represented by formula (1) using the above-mentioned purification method of the present invention.

[0074] (Polymer composition) The polymer composition of the present invention contains a cyclic olefin ring-opening polymer containing structural units derived from a norbornene imide monomer represented by the above formula (1), and optionally further contains a solvent. The polymer composition of the present invention is characterized by having a transmittance of 90% or more for light with a wavelength of 550 nm. Therefore, the polymer composition of the present invention contains few impurities and is sufficiently suppressed from being discolored. Therefore, the polymer composition of the present invention can be suitably used for producing a resin composition useful as a material for various molded articles such as optical elements. The polymer composition of the present invention preferably has a transmittance of 95% or more, more preferably 98% or more, to light with a wavelength of 550 nm.

[0075] <Solvent> The solvent optionally contained in the polymer composition of the present invention is not particularly limited, and water or the same organic solvent as described above in the section "Purification method of the present invention" can be used.

[0076] <Content of cyclic olefin ring-opening polymer> The content of the cyclic olefin ring-opening polymer in the polymer composition of the present invention is preferably 50% by mass or more, more preferably 70% by mass or more.

[0077] <Weight-average molecular weight of cyclic olefin ring-opening polymer> The cyclic olefin ring-opening polymer preferably has a weight-average molecular weight of 10,000 or more, more preferably 15,000 or more, and even more preferably 20,000 or more, and preferably 100,000 or less, more preferably 80,000 or less, and even more preferably 60,000 or less. When the weight-average molecular weight of the cyclic olefin ring-opening polymer is equal to or greater than the above-mentioned lower limit, a decrease in strength of a resin molded article obtained using the cyclic olefin ring-opening polymer can be suppressed. Furthermore, when the weight-average molecular weight of the cyclic olefin ring-opening polymer is equal to or less than the above-mentioned upper limit, molding defects caused by poor flowability during molding of the cyclic olefin ring-opening polymer can be suppressed. In the present invention, the "weight average molecular weight" can be measured by the method described in the Examples. The weight average molecular weight of the cyclic olefin ring-opening polymer can be adjusted, for example, by changing the type and / or amount of the monomer used in preparing the cyclic olefin ring-opening polymer, or the type and / or amount of the molecular weight regulator (chain transfer agent).

[0078] <Glass transition temperature of cyclic olefin ring-opening polymer> The cyclic olefin ring-opening polymer preferably has a glass transition temperature of 120°C or higher, more preferably 125°C or higher, and even more preferably 130°C or higher, and preferably 200°C or lower, more preferably 190°C or lower, and even more preferably 180°C or lower. When the glass transition temperature of the cyclic olefin ring-opening polymer is equal to or higher than the above-mentioned lower limit, deterioration of heat resistance and deterioration of optical properties due to thermal deformation or the like can be suppressed. Furthermore, when the glass transition temperature of the cyclic olefin ring-opening polymer is equal to or lower than the above-mentioned upper limit, oxidative degradation of the cyclic olefin ring-opening polymer caused by excessively high processing temperatures when molding the cyclic olefin ring-opening polymer can be suppressed. In the present invention, the "glass transition temperature" can be measured by the method described in the examples. The glass transition temperature of the cyclic olefin ring-opening polymer can be adjusted, for example, by changing the type and / or amount of the monomer used in preparing the cyclic olefin ring-opening polymer.

[0079] <Abbe number of cyclic olefin ring-opening polymer> The cyclic olefin ring-opening polymer preferably has an Abbe number (vd) of less than 50, more preferably 46 or less, and even more preferably 42 or less. When the Abbe number of the cyclic olefin ring-opening polymer is less than the above upper limit, the cyclic olefin ring-opening polymer can be suitably used for applications other than optical elements with high Abbe numbers. The lower limit of the Abbe number is not particularly limited, but is usually about 20. In the present invention, the "Abbe number" can be measured by the method described in the examples.

[0080] <Birefringence of cyclic olefin ring-opening polymer> The birefringence of the cyclic olefin ring-opening polymer is preferably 300 or less, more preferably 200 or less, and even more preferably 100 or less. When the birefringence of the cyclic olefin ring-opening polymer water is the above upper limit or less, the optical properties of the resulting resin molded article as an optical element can be improved. In the present invention, the "birefringence" can be measured by the method described in the examples.

[0081] <Refractive index of cyclic olefin ring-opening polymer> The refractive index of the cyclic olefin ring-opening polymer water is preferably 1.5 or more, more preferably 1.52 or more, and even more preferably 1.54 or more. When the refractive index of the cyclic olefin ring-opening polymer is equal to or more than the above lower limit, the degree of freedom in designing the resulting resin molded article as an optical element can be increased. In the present invention, the "refractive index" can be measured by the method described in the examples.

[0082] <Manufacturing method> The polymer composition of the present invention can be suitably obtained by purifying a treatment target containing a cyclic olefin ring-opening polymer using the above-mentioned purification method of the present invention. Also, the polymer composition of the present invention can be suitably obtained by polymerizing the above-mentioned monomer composition of the present invention, or by polymerizing the above-mentioned monomer composition of the present invention with a cyclic olefin compound capable of forming the above-mentioned other structural unit.

[0083] (Resin composition) The resin composition of the present invention contains the above-mentioned monomer composition or polymer composition of the present invention, and optionally further contains polymeric materials other than the monomer composition and polymer composition of the present invention and / or various additives.

[0084] The polymeric materials and additives that can be contained in the resin composition are not particularly limited, and examples thereof include the polymeric materials and additives described in JP-A-10-139865.

[0085] Among these, it is preferable that the resin composition contains an antioxidant such as a phenol-based antioxidant, a phosphorus-based antioxidant, or a sulfur-based antioxidant.

[0086] The polymeric material and additives can be mixed with the monomer composition or polymer composition by any method without particular limitation as long as they can be sufficiently dispersed in the monomer composition or polymer composition. Specifically, the polymeric material and additives may be added at any stage during the preparation of the monomer composition or polymer composition, may be kneaded with the monomer composition or polymer composition using a kneader, or may be mixed with the monomer composition or polymer composition in a molding device. The amounts of polymeric materials and additives to be blended are not particularly limited as long as the effects of the present invention are not impaired, but can be, for example, 0.01 parts by mass or more and 2.0 parts by mass or less per 100 parts by mass of the cyclic olefin ring-opening polymer. The amount of antioxidant to be added is not particularly limited as long as the effects of the present invention are not impaired, but can be, for example, 0.01 parts by mass or more and 2.0 parts by mass or less per 100 parts by mass of the cyclic olefin ring-opening polymer.

[0087] (Resin molded body) The resin molded article of the present invention is obtained by molding the resin composition of the present invention containing the above-mentioned polymer composition into any shape. Since the resin molded article of the present invention contains the above-mentioned polymer composition of the present invention, it can exhibit excellent transparency.

[0088] The molding method is not particularly limited as long as it can mold the resin composition, and examples that can be used include injection molding, extrusion blow molding, injection blow molding, two-stage blow molding, multi-layer blow molding, connection blow molding, stretch blow molding, rotational molding, vacuum molding, extrusion molding, calendar molding, solution casting, hot press molding, and inflation molding. Of these, extrusion molding is preferred.

[0089] The resin molded article of the present invention is preferably an optical element, more preferably a lens. The lens is not particularly limited, and can be obtained, for example, by uniformly heating and melting the resin composition of the present invention to form a preform, then pouring the preform into a mold, and then cooling it.

[0090] (Method of manufacturing resin molded body) The method for producing a resin molded article of the present invention includes a step of molding a resin composition containing a cyclic olefin ring-opening polymer, wherein the cyclic olefin ring-opening polymer contains structural units derived from a norbornene imide monomer represented by formula (1) obtained by the above-described purification method of the present invention, or is a cyclic olefin ring-opening polymer obtained by the above-described purification method of the present invention. According to the method for producing a resin molded article of the present invention, a resin molded article having excellent transparency can be produced.

[0091] The molding method used in the molding step is not particularly limited as long as it can mold the resin composition, and the methods described above in the section "Resin Molded Product" can be used. [Example]

[0092] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. In the following description, the terms "%" and "parts" representing amounts are based on mass unless otherwise specified. Furthermore, in a polymer produced by copolymerizing multiple types of monomers, the proportion of a structural unit formed by polymerizing a certain monomer in the polymer usually coincides with the ratio (feed ratio) of that certain monomer to all monomers used in the polymerization of the polymer, unless otherwise specified.

[0093] <Light transmittance> 0.2 g of the norbornene imide monomer prepared in the Examples and Comparative Examples was dissolved in 1.8 g of a solvent (methyl ethyl ketone) to obtain a sample with a concentration of 10% by mass. The transmittance of the obtained sample to light of 550 nm was measured using a spectrophotometer. The higher the light transmittance, the more coloration was suppressed. <Polymerization conversion rate> After the polymerization reaction was completed, the amount of the remaining monomer in the reaction solution was measured by gas chromatography, and the amount was calculated from the measured value. <Hydrogen conversion rate> 1 The number of moles of hydrogenated carbon-carbon double bonds was measured by H-NMR spectroscopy, and the ratio to the number of moles of carbon-carbon double bonds before hydrogenation was calculated to determine the hydrogenation rate of non-aromatic carbon-carbon unsaturated bonds and the hydrogenation rate of aromatic carbon-carbon unsaturated bonds in the hydrogenated cyclic olefin ring-opening polymer. <Weight average molecular weight> The weight-average molecular weight (Mw) of the cyclic olefin ring-opening polymer was calculated in polystyrene equivalent terms using gel permeation chromatography (Tosoh Corporation, "HLC-8020" using a combination of three columns: TSKgel SuperH2000, TSKgel SuperH4000, and TSKgel SuperH5000). Tetrahydrofuran (THF) was used as the developing solvent. <Glass transition temperature> The glass transition temperature (Tg) of the cyclic olefin ring-opening polymer was measured using a differential scanning calorimeter (manufactured by SII Nano Technology, "DSC6220") at a temperature rise rate of 10°C / min according to JIS K7121. <Birefringence> The obtained dried resin pellets were injection molded using an injection molding machine (FANUC Corporation, product number α-100B) under the following conditions: resin temperature: 20°C lower than the glass transition temperature of the hydrogenated cyclic olefin ring-opening polymer (= Tg - 20°C); mold temperature: 130°C lower than the glass transition temperature of the hydrogenated cyclic olefin ring-opening polymer (= Tg - 130°C); and cycle time: 1 minute, to obtain a flat resin molded product measuring 80 mm x 10 mm x 4 mm. The retardation values ​​of the obtained resin molding in the direction perpendicular to the resin flow direction at a point 10 mm from the gate of the resin molding were measured using a birefringence meter (Photonic Lattice, product name: WPA-200(-L)) under light with a wavelength of 543 nm. The maximum value among the measured values ​​was taken as the birefringence index. <Refractive index> A 5 mm thick sheet-like resin molding was obtained in the same manner as the resin molding obtained in the measurement of birefringence, except that the obtained resin composition was changed from 80 mm × 10 mm × 4 mm to 50 mm × 50 mm × 5 mm. The obtained 5 mm thick sheet-like resin molding was left for 20 hours in an atmosphere at a temperature 15°C lower than the glass transition temperature of the hydrogenated cyclic olefin ring-opening polymer (= Tg - 15°C), and this was used as a measurement sample. The refractive index (n d , n C , n F ) was measured. In Table 1, the refractive index (n d ) is shown. <Abbe number> The refractive index (n d , n C , n F ) to calculate the Abbe number (ν d ) was calculated.

number

[0094] (Example 1-1) A 30 ml three-neck flask was charged with 11.1 g of 5-norbornene-2,3-dicarboxylic anhydride and 8 ml of 2-methylaniline and heated in an oil bath. After 19 hours of reaction, the disappearance of the raw materials was confirmed by GC (gas chromatography) or TLC (thin layer chromatography), and the reaction solution was cooled. The reaction solution and 50 ml of toluene were added to a recovery flask and heated. 100 ml of heptane was added, and the mixture was allowed to cool and recrystallized (first recrystallization step). The resulting solid was filtered and dried, yielding 15.1 g of a pale purple solid as crude crystals. Toluene and ethyl acetate were added to the resulting crude crystals, which were then dissolved by heating and purified by column chromatography (silica gel) (purification step). The target fraction was concentrated to a certain extent, heptane was added, the mixture was allowed to cool, and recrystallization was carried out (second recrystallization step). The resulting solid was filtered and dried to obtain 13.7 g of a white solid (N-2-methylphenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide (hereinafter sometimes abbreviated as "NBTI") as a norbornene imide monomer represented by formula (1)) (yield: 80%). The transmittance of light with a wavelength of 550 nm was then measured. The results are shown in Table 1.

[0095] (Example 1-2) A 30 ml three-neck flask was charged with 12.1 g of 5-norbornene-2,3-dicarboxylic anhydride and 10 ml of 2,6-dimethylaniline, and heated in an oil bath. The same procedure as in Example 1-1 was otherwise performed to obtain 16.0 g of a white solid (N-2,6-dimethylphenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide (hereinafter sometimes abbreviated as "NBXI") as the norbornene imide monomer represented by formula (1)). (Yield: 81%) The transmittance of light with a wavelength of 550 nm was then measured. The results are shown in Table 1.

[0096] (Examples 1-3) A 30 ml three-neck flask was charged with 10.3 g of 5-norbornene-2,3-dicarboxylic anhydride and 13 ml of 2,6-diisopropylaniline and heated in an oil bath. The same procedure as in Example 1-1 was otherwise performed to obtain 14.0 g of a white solid (N-2,6-diisopropylphenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide (hereinafter sometimes abbreviated as "NBDII") as a norbornene imide monomer represented by formula (1)) (yield: 69%). The transmittance of light with a wavelength of 550 nm was then measured. The results are shown in Table 1.

[0097] (Examples 1-4) In Example 1-2, the adsorbent was changed from silica gel to activated clay, and instead of purification by column chromatography, a slurry containing the crude crystals, the adsorbent, and a solvent (methyl ethyl ketone) was filtered, and the filtrate obtained was used for recrystallization in the second recrystallization step. Except for this, a white solid (NBXI) was obtained (yield: 81%) in the same manner as in Example 1-2. The transmittance of light with a wavelength of 550 nm was then measured. The results are shown in Table 1.

[0098] (Examples 1-5) In Example 1-2, the adsorbent was changed from silica gel to activated alumina. Otherwise, the same procedure as in Example 1-2 was carried out to obtain a white solid (NBXI) (yield: 81%). The transmittance of light with a wavelength of 550 nm was then measured. The results are shown in Table 1.

[0099] (Examples 1 to 6) In Example 1-2, the adsorbent was changed from silica gel to activated carbon. Otherwise, the same procedure as in Example 1-2 was carried out to obtain a white solid (NBXI) (yield: 81%). The transmittance of light with a wavelength of 550 nm was then measured. The results are shown in Table 1.

[0100] (Comparative Example 1-1) A 30 ml three-neck flask was charged with 9.8 g of 5-norbornene-2,3-dicarboxylic anhydride and 6 ml of aniline and heated in an oil bath. After 19 hours of reaction, the disappearance of the raw materials was confirmed by gas chromatography or thin-layer chromatography (TLC), and the reaction solution was cooled. The reaction solution and 50 ml of toluene were added to a recovery flask and heated. 100 ml of heptane was added, and the mixture was allowed to cool and recrystallize. The resulting solid was filtered and dried to obtain 14.6 g of a white solid (N-phenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide (hereinafter sometimes abbreviated as "NBPI")) (yield: 90%). The transmittance of light with a wavelength of 550 nm was then measured, and the results are shown in Table 1. Note that NBPI is a norbornene imide monomer that does not color, and therefore has good transmittance of light with a wavelength of 550 nm.

[0101] (Comparative Example 1-2) A 30 ml three-neck flask was charged with 11.1 g of 5-norbornene-2,3-dicarboxylic anhydride and 8 ml of 2-methylaniline, and heated in an oil bath. The same procedure as in Comparative Example 1-1 was otherwise performed, yielding 15.1 g of a pale purple solid (NBTI) (yield: 88%). The transmittance of light with a wavelength of 550 nm was then measured. The results are shown in Table 1.

[0102] (Comparative Examples 1-3) 21 g of 5-norbornene-2,3-dicarboxylic anhydride and 17.1 g of 2,6-dimethylaniline were placed in a 300 ml three-neck flask and heated in an oil bath. The same procedure as in Comparative Example 1-1 was otherwise performed to obtain 30.4 g of a pale purple solid (NBXI) (yield: 89%). The transmittance of light with a wavelength of 550 nm was then measured. The results are shown in Table 1.

[0103] (Comparative Examples 1-4) 10.3 g of 5-norbornene-2,3-dicarboxylic anhydride and 13 ml of 2,6-diisopropylaniline were placed in a 30 ml three-neck flask and heated in an oil bath. The same procedure as in Comparative Example 1-1 was otherwise performed to obtain 15.7 g of a deep purple solid (NBDII) (yield: 77%). The transmittance of light with a wavelength of 550 nm was then measured. The results are shown in Table 1. [Table 1]

[0104] The results shown in Table 1 show that the norbornene imide monomers represented by formula (1) of Examples 1-1 to 1-6 purified using the purification method of the present invention have high light transmittance and are suppressed from coloring.

[0105] Example 2-1 60 parts of NBDII prepared in Example 1-3, 40 parts of deltacyclene (hereinafter sometimes abbreviated as "DCL") as a polar group-free cyclic olefin monomer, 2.5 parts of 1-hexene as a chain transfer agent, 0.025 parts of 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene[2-(isopropoxy)-5-(N,N-dimethylaminosulfonyl)phenyl]methyleneruthenium(II) dichloride as a polymerization catalyst, and 1000 parts of tetrahydrofuran as a solvent were charged into a nitrogen-purged glass pressure-resistant reactor, and the entire contents were stirred at 65 °C for 3 hours to carry out ring-opening polymerization. The polymerization conversion of the resulting ring-opened polymer was 96%, and the weight-average molecular weight of the resulting cyclic olefin ring-opened polymer was 21,100. The resulting polymerization reaction solution was then placed in an autoclave and stirred at 150°C under a hydrogen pressure of 4.5 MPa for 6 hours to carry out a hydrogenation reaction. The solution was filtered through a radiolite-precoated funnel to obtain a hydrogenated cyclic olefin ring-opening polymer. The hydrogenation rate of non-aromatic carbon-carbon unsaturated bonds in the obtained hydrogenated cyclic olefin ring-opening polymer was 90.0% or more, and the hydrogenation rate of aromatic carbon-carbon unsaturated bonds in the obtained hydrogenated cyclic olefin ring-opening polymer was 0%. The color of the resulting cyclic olefin ring-opening polymer was evaluated, and the results are shown in Table 2. Next, 100 parts of the obtained hydrogenated cyclic olefin ring-opening polymer was mixed with 1 part of an antioxidant (tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane; "Irganox (registered trademark) 1010" manufactured by BASF Japan Ltd.) to obtain a resin composition containing the hydrogenated cyclic olefin ring-opening polymer. The resulting resin composition was then fed into a twin-screw extruder (Toshiba Machine Co., Ltd., "TEM-37B") equipped with four die holes with an inner diameter of 3 mm. The resin composition was then hot-melt extruded using the twin-screw extruder to form a strand-shaped molded body. This molded body was shredded with a strand cutter to obtain dried resin pellets. The operating conditions for the twin-screw extruder were as follows: Barrel temperature setting: 270℃~280℃ Die temperature setting: 250℃ Screw rotation speed: 145 rpm Feeder rotation speed: 50 rpm Various measurements and evaluations were then carried out, and the results are shown in Table 2.

[0106] (Example 2-2) In Example 2-1, 70 parts of NBXI produced in Example 1-2 were used instead of 60 parts of NBDII, and the amount of DCL was changed from 40 parts to 30 parts, except that in Example 2-1, a cyclic olefin ring-opening polymer, a resin composition, and resin pellets were produced in the same manner as in Example 2-1. Various measurements and evaluations were then carried out. The results are shown in Table 2.

[0107] (Example 2-3) In Example 2-1, except that the amount of NBDII was changed from 60 parts to 90 parts and the amount of DCL was changed from 40 parts to 10 parts, a cyclic olefin ring-opening polymer, a resin composition, and resin pellets were produced in the same manner as in Example 2-1. Various measurements and evaluations were then carried out. The results are shown in Table 2.

[0108] (Examples 2-4) In Example 2-2, the amount of NBXI was changed from 70 parts to 50 parts, and the amount of DCL was changed from 30 parts to 50 parts. A cyclic olefin ring-opening polymer, a resin composition, and resin pellets were produced in the same manner as in Example 2-2. Various measurements and evaluations were then carried out. The results are shown in Table 2.

[0109] (Examples 2-5) In Example 2-1, 60 parts of NBDII were replaced with 60 parts of NBTI produced in Example 1-1, the amount of DCL was changed from 40 parts to 20 parts, and 20 parts of 2-ethylidene-1,2,3,4,4a,5,8,8a-octahydro-1,4:5,8-dimethanonaphthalene (hereinafter sometimes abbreviated as "ETD") was further used as the cyclic olefin monomer without a polar group in addition to DCL. A cyclic olefin ring-opening polymer, a resin composition, and resin pellets were produced in the same manner as in Example 2-1. Various measurements and evaluations were then performed. The results are shown in Table 2.

[0110] (Examples 2-6) In Example 2-5, the amount of NBTI was changed from 60 parts to 75 parts, the amount of ETD was changed from 20 parts to 25 parts, the amount of 1-hexene was changed from 2.5 parts to 1.0 part, and no DCL was used. A cyclic olefin ring-opening polymer, a resin composition, and resin pellets were produced in the same manner as in Example 2-5. Various measurements and evaluations were then performed. The results are shown in Table 2.

[0111] (Comparative Example 2-1) In Example 2-6, 75 parts of NBPI produced in Comparative Example 1-1 were used instead of 60 parts of NBDII, and the amount of 1-hexene added was changed from 1.0 part to 0.75 part. A cyclic olefin ring-opening polymer, a resin composition, and resin pellets were produced in the same manner as in Example 2-6. Various measurements and evaluations were then performed. The results are shown in Table 2. Note that, because NBPI is a norbornene imide monomer that does not color, the color of the cyclic olefin ring-opening polymer was good.

[0112] (Comparative Example 2-2) In Example 2-1, a cyclic olefin ring-opening polymer, a resin composition, and resin pellets were produced in the same manner as in Example 2-1, except that the NBDII produced in Comparative Example 1-4 was used. Various measurements and evaluations were then carried out. The results are shown in Table 2.

[0113] (Comparative Example 2-3) In Example 2-2, a cyclic olefin ring-opening polymer, a resin composition, and resin pellets were produced in the same manner as in Example 2-2, except that the NBXI produced in Comparative Example 1-3 was used. Various measurements and evaluations were then carried out. The results are shown in Table 2.

[0114] (Comparative Example 2-4) In Example 2-3, a cyclic olefin ring-opening polymer, a resin composition, and resin pellets were produced in the same manner as in Example 2-3, except that the NBDII produced in Comparative Example 1-4 was used. Various measurements and evaluations were then carried out. The results are shown in Table 2.

[0115] (Comparative Example 2-5) In Example 2-4, a cyclic olefin ring-opening polymer, a resin composition, and resin pellets were produced in the same manner as in Example 2-4, except that the NBXI produced in Comparative Example 1-3 was used. Various measurements and evaluations were then carried out. The results are shown in Table 2.

[0116] (Comparative Example 2-6) In Example 2-5, a cyclic olefin ring-opening polymer, a resin composition, and resin pellets were produced in the same manner as in Example 2-5, except that the NBTI produced in Comparative Example 1-2 was used. Various measurements and evaluations were then carried out. The results are shown in Table 2.

[0117] (Comparative Example 2-7) In Example 2-6, a cyclic olefin ring-opening polymer, a resin composition, and resin pellets were produced in the same manner as in Example 2-6, except that the NBTI produced in Comparative Example 1-2 was used. Various measurements and evaluations were then carried out. The results are shown in Table 2. [Table 2]

[0118] The results shown in Table 2 show that the cyclic olefin ring-opening polymers of Examples 2-1 to 2-6, which were produced using the norbornene imide monomer represented by formula (1) purified using the purification method of the present invention, had good color and were inhibited from discoloring. [Industrial Applicability]

[0119] According to the present invention, it is possible to provide a method for purifying a treatment target containing a norbornene imide monomer or a cyclic olefin ring-opening polymer containing a structural unit derived from a norbornene imide monomer. Furthermore, according to the present invention, it is possible to provide a monomer composition containing a norbornene imide monomer in which coloration is sufficiently suppressed, and a polymer composition containing a cyclic olefin ring-opening polymer in which coloration is sufficiently suppressed. Another object of the present invention is to provide a resin composition that can be advantageously used as a material for various molded articles such as optical elements, a resin molded article formed using the resin composition, and a method for producing the resin molded article.

Claims

1. A process for preparing a treatment object containing a norbornene imide monomer represented by the following formula (1) or a cyclic olefin ring-opening polymer containing a structural unit derived from the norbornene imide monomer represented by the following formula (1); and purifying the object to be treated using an adsorbent. 【Chemical 1】 (In formula (1), R １ ~R ５ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted alkenyl group, an optionally substituted alkynyl group, an optionally substituted alkoxy group, an optionally substituted aromatic hydrocarbon ring group, or an optionally substituted aromatic heterocyclic group; R １ ~R ５ Two or more of them may be bonded to form a ring. １ ~R ５ Neither of these is a hydrogen atom.)

2. The purification method according to claim 1 , further comprising a step of purifying the material to be treated by recrystallization before carrying out purification using the adsorbent.

3. The purification method according to claim 2 , further comprising a step of purifying the object to be treated, which has been purified using the adsorbent, by recrystallization.

4. 4. The purification method according to claim 1, wherein the adsorbent is at least one selected from the group consisting of activated clay, silica gel, activated alumina, and activated carbon.

5. The norbornene imide monomer is represented by the following formula (1): A monomer composition having a transmittance of 90% or more for light having a wavelength of 550 nm. 【Chemistry 2】 (In formula (1), R １ ~R ５ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted alkenyl group, an optionally substituted alkynyl group, an optionally substituted alkoxy group, an optionally substituted aromatic hydrocarbon ring group, or an optionally substituted aromatic heterocyclic group; R １ ~R ５ Two or more of them may be bonded to form a ring. １ ~R ５ Neither of these is a hydrogen atom.)

6. The polymer contains a cyclic olefin ring-opening polymer containing a structural unit derived from a norbornene imide monomer represented by the following formula (1): A polymer composition having a transmittance of 90% or more for light with a wavelength of 550 nm. 【Chemistry 3】 (In formula (1), R １ ~R ５ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted alkenyl group, an optionally substituted alkynyl group, an optionally substituted alkoxy group, an optionally substituted aromatic hydrocarbon ring group, or an optionally substituted aromatic heterocyclic group; R １ ~R ５ Two or more of them may be bonded to form a ring. １ ~R ５ Neither of these is a hydrogen atom.)

7. A resin composition comprising the monomer composition according to claim 5 .

8. A resin composition comprising the polymer composition according to claim 6.

9. A resin molded article obtained by molding the resin composition according to claim 8.

10. The method includes a step of molding a resin composition containing a cyclic olefin ring-opening polymer, A method for producing a resin molded article, wherein the cyclic olefin ring-opening polymer contains structural units derived from the norbornene imide monomer represented by formula (1) obtained by the purification method according to claim 1.

11. The method includes a step of molding a resin composition containing a cyclic olefin ring-opening polymer, The method for producing a resin molded article, wherein the cyclic olefin ring-opening polymer is a cyclic olefin ring-opening polymer obtained by the purification method according to claim 1.

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