JPWO1998018838A1 - Modified thermoplastic norbornene polymer and method for producing same - Google Patents

Abstract

(57) [Abstract] A modified thermoplastic norbornene-based polymer having a graft modification rate of at least 10 mol% and a number-average molecular weight (Mn) of 500 to 500,000, obtained by graft-modifying a thermoplastic norbornene-based polymer selected from ring-opening polymers of norbornene-based monomers and hydrogenated products thereof with at least one unsaturated compound selected from the group consisting of unsaturated epoxy compounds and unsaturated carboxylic acid compounds; a method for producing the modified thermoplastic norbornene-based polymer; and a crosslinkable polymer composition containing the modified thermoplastic norbornene-based polymer and a crosslinking agent.

Description

[Detailed Description of the Invention] Modified Thermoplastic Norbornene-Based Polymers and Their Production Methods <Technical Field> The present invention relates to modified thermoplastic norbornene-based polymers obtained by graft-modifying a ring-opening polymer or its hydrogenated product of a norbornene-based monomer with an unsaturated epoxy compound or an unsaturated carboxylic acid compound, and to a production method thereof. More specifically, the present invention relates to modified thermoplastic norbornene-based polymers that exhibit excellent electrical properties such as dielectric constant, adhesion to other materials such as metals (metal foils, metal wiring, etc.) and silicon wafers, heat resistance, and moisture resistance, and that can be prepared into highly concentrated solutions and exhibit excellent uniform dispersion of various compounding agents in the solution, and to a production method thereof.

Taking advantage of these properties, the modified thermoplastic norbornene polymer of the present invention can be suitably used in the field of electrical and electronic equipment, for example, as an impregnation resin for prepregs, sheets, interlayer insulating films, etc.

<Background Art> In recent years, the rapid development of an information-driven society has led to a strong demand in the electronics industry for faster information processing and smaller equipment. To achieve higher speeds and smaller sizes in the high-frequency range, insulating materials with sufficiently low dielectric constants are required for electronic components used in electrical and electronic equipment, such as semiconductors, ICs, hybrid ICs, printed wiring boards, display elements, and display components. Furthermore, to ensure high reliability over the long term, insulating materials with excellent heat resistance, including solder heat resistance, and moisture resistance are also required. Furthermore, in the field of information processing equipment, such as computers and communications devices, the need for faster information processing speeds is growing, while miniaturization and weight reduction for portability are also becoming increasingly important. Consequently, the circuits installed in these devices require higher performance, such as multi-layered circuit boards, higher precision, and finer design.

In recent years, multi-chip modules (MCMs) for flip-chip packaging have been developed, enabling miniaturization and high-density packaging. In addition to the required characteristics described above, the insulating materials used in these MCM interlayer insulation films must also have sufficient adhesion to the silicon wafer or other substrate and conductive layers (e.g., metal foil or vapor-deposited metal layer) to ensure long-term reliability. Furthermore, MCMs require smaller via diameters due to shorter wiring pitches, so the insulating materials must be photosensitive to enable microfabrication.

Photosensitive polyimide resins and epoxy resins have been investigated as insulating materials for MCMs. However, conventional photosensitive polyimide resins have drawbacks, such as insufficient electrical properties, such as dielectric constant, at high frequencies, and insufficient moisture resistance, making it difficult to achieve high long-term reliability. Attempts have been made to introduce photosensitive groups, such as allyl groups, into epoxy resins to impart photosensitivity, but these methods have drawbacks, such as a significant decrease in electrical properties, such as dielectric constant, and insufficient thermal stability.

On the other hand, circuit boards are manufactured by impregnating a reinforcing substrate such as glass cloth with a resin varnish and drying it to form a semi-cured sheet (prepreg). Next, copper foil or a copper-clad sheet for an outer layer, the prepreg, and a copper-clad sheet for an inner layer are sequentially laid between mirror-finished sheets, and then the resulting assembly is pressurized and heated to fully cure the resin. Conventional resin materials used for this purpose include phenolic resin, epoxy resin, polyimide resin, fluororesin, and polybutadiene resin.

However, thermosetting resins such as phenolic resin, epoxy resin, and polyimide resin generally have a high dielectric constant of 4.0 or higher and insufficient electrical properties, making it difficult to increase the speed and reliability of computational processing when using circuit boards made with these thermosetting resins. Meanwhile, circuit boards made with thermoplastic resins such as fluororesin and polybutadiene resin have poor heat resistance, resulting in cracking and peeling during soldering, and also have poor dimensional stability, making multi-layer construction difficult.

Therefore, in recent years, the use of thermoplastic norbornene resins as insulating materials has been proposed.

For example, Japanese Patent Laid-Open Publication No. 62-34924 discloses a method in which a norbornene-based resin having an intrinsic viscosity [η] of 1.15 to 2.22 measured in decalin at 135°C is synthesized by addition polymerization of a norbornene-based cyclic olefin and ethylene, and the norbornene-based resin is kneaded with a crosslinking aid, pulverized, impregnated with an organic peroxide solution, the solution is removed, and the resulting mixture is press-molded to crosslink.

However, this method suffers from complex process steps, difficulty in preparing a highly concentrated solution of norbornene-based resins, and difficulty in uniformly dispersing organic peroxides and other compounding agents. Therefore, to fabricate prepregs using resin solutions obtained by this method, low-concentration solutions are required. However, impregnating a reinforcing substrate with a low-concentration solution requires a long drying time at room temperature to eliminate tack, during which the substrate must be left to stand to prevent deformation, resulting in poor productivity. Furthermore, various compounding agents must be added depending on the application. However, the high viscosity of the solution not only prevents uniform dispersion, but also leads to two-phase separation between the resin solution and the compounding agents, depending on the type and amount of compounding agent. Immersing a reinforcing substrate in a two-phase solution fails to produce a prepreg with uniform impregnation of each component. Furthermore, when copper foil is laminated onto the resulting prepreg or other molded product, the peel strength is insufficient, resulting in durability issues.

Japanese Patent Laid-Open Publication No. 6-248164 discloses a method for producing sheets, prepregs, and the like by dispersing a thermoplastic hydrogenated ring-opened norbornene resin, an organic peroxide, a crosslinking aid, and a flame retardant such as a brominated bisphenol in a solvent, casting the resulting solution or impregnating a reinforcing substrate, then removing the solvent and thermally crosslinking the resulting solution. However, when using the norbornene resin specifically disclosed in this publication, it is difficult to achieve a sufficiently high solids concentration, resulting in insufficient productivity during the drying process. Furthermore, this method has limitations on the types and amounts of compounding ingredients that can be uniformly dispersed, and the peel strength from the copper foil is insufficient, making it inapplicable to some applications.

Japanese Patent Application Laid-Open No. 62-27412 proposes a modified cyclic olefin copolymer in which an unsaturated epoxy compound such as allyl glycidyl ether is grafted onto an addition copolymer of ethylene and a norbornene-based monomer. Japanese Patent Application Laid-Open No. 8-20692 proposes a resin composition containing a cyclic olefin resin having a carboxylic acid derivative residue and a thermal crosslinking agent and/or a photocrosslinking agent. Japanese Patent Application Laid-Open No. 8-259784 proposes a resin composition containing a cyclic olefin resin having an epoxy group and a crosslinking agent. All of these resin materials have been reported to have excellent electrical properties, heat resistance, adhesion, etc.

However, the modified polymers specifically disclosed in these prior art documents all have insufficient graft modification rates, resulting in insufficient adhesion to other materials such as metals and silicon wafers. Furthermore, they also have insufficient heat resistance, making them susceptible to deformation and cracking during solder reflow and sputtering processes.

<Disclosure of the Invention> The object of the present invention is to provide a modified thermoplastic norbornene-based polymer that exhibits excellent electrical properties, such as dielectric constant in the high frequency range, heat resistance, moisture resistance, and thermal stability, as well as excellent adhesion to other materials such as metals and silicon wafers, and a method for producing the same.

Another object of the present invention is to provide a crosslinkable polymer composition containing an epoxy group-containing norbornene polymer, which has excellent electrical properties such as dielectric constant in the high frequency range, heat resistance, moisture resistance, and thermal stability, and also has excellent adhesion to other materials such as metals and silicon wafers, and is suitable for incorporation with a crosslinking agent.

Another object of the present invention is to provide a modified thermoplastic norbornene-based polymer that is excellent in heat resistance, electrical properties such as dielectric constant, and peel strength from metal foil, can be prepared into a highly concentrated solution, and exhibits excellent uniform dispersion of compounding ingredients in the solution; a method for producing the same; and a crosslinkable polymer composition containing the modified thermoplastic norbornene-based polymer and a crosslinking agent.

The present inventors conducted extensive research to overcome the problems of the prior art as described above, and as a result, discovered that the above-mentioned objectives can be achieved by graft-modifying, at a high modification rate, a ring-opening polymer of a norbornene-based monomer or a hydrogenated product thereof having a molecular weight within a specific range with at least one unsaturated compound selected from the group consisting of unsaturated epoxy compounds and unsaturated carboxylic acid compounds.

Among the modified thermoplastic norbornene polymers of the present invention, polymers with a graft modification rate of 10 mol % or more and a relatively low molecular weight of 500 to 20,000 number-average molecular weight (Mn) can be prepared into highly concentrated solutions, and various compounding ingredients can be uniformly dispersed in the solutions even at high concentrations. Furthermore, these solutions exhibit excellent impregnation properties for reinforcing substrates and good film-forming properties, allowing prepregs and sheets to be prepared using crosslinkable polymer compositions containing the modified thermoplastic norbornene polymer and a crosslinking agent. Furthermore, laminates prepared from the prepregs and sheets exhibit excellent heat resistance and dielectric constant, and when used in metal-clad laminates, they exhibit excellent peel strength from the metal layer.

Among the modified thermoplastic norbornene polymers of the present invention, relatively high molecular weight polymers having a graft modification rate of 10 mol % or more and a number average molecular weight (Mn) exceeding 20,000 exhibit excellent electrical properties such as dielectric constant in the high frequency range, heat resistance, moisture resistance, and thermal stability. In addition, they also exhibit excellent adhesion to other materials such as metals and silicon wafers, making them particularly suitable for use as overcoat films, interlayer insulating films, and the like.

Furthermore, the modified thermoplastic norbornene-based polymer of the present invention can be crosslinked by various methods such as thermal crosslinking and photocrosslinking by selecting the type of crosslinking agent.

The present invention has been completed based on these findings.

Thus, according to the present invention, a thermoplastic norbornene-based polymer selected from ring-opening polymers of norbornene-based monomers and hydrogenated products thereof is graft-modified with at least one unsaturated compound selected from the group consisting of unsaturated epoxy compounds and unsaturated carboxylic acid compounds, thereby providing a modified thermoplastic norbornene-based polymer having a graft modification rate of at least 10 mol % and a number-average molecular weight (Mn) of 500 to 500,000.

The present invention also provides a method for producing a modified thermoplastic norbornene polymer having a number average molecular weight (Mn) of 500 to 500,000 and a graft modification rate of at least 10 mol %, which comprises reacting a thermoplastic norbornene polymer having a number average molecular weight (Mn) of 500 to 500,000, the number average molecular weight (Mn) being selected from ring-opening polymers of norbornene monomers and hydrogenated products thereof, with at least one unsaturated compound selected from the group consisting of unsaturated epoxy compounds and unsaturated carboxylic acid compounds, in the presence of an organic peroxide.

Furthermore, according to the present invention, there is provided a crosslinkable polymer composition containing a modified thermoplastic norbornene-based polymer having a number average molecular weight (Mn) of 500 to 500,000 and a graft modification rate of at least 10 mol %, the modified thermoplastic norbornene-based polymer being selected from ring-opening polymers of norbornene-based monomers and hydrogenated products thereof, and a crosslinking agent. The modified thermoplastic norbornene-based polymer is obtained by graft-modifying the thermoplastic norbornene-based polymer with at least one unsaturated compound selected from the group consisting of unsaturated epoxy compounds and unsaturated carboxylic acid compounds.

BEST MODE FOR CARRYING OUT THE INVENTION Modified Thermoplastic Norbornene Polymer The modified thermoplastic norbornene polymer used in the present invention is a thermoplastic norbornene polymer having a number average molecular weight (Mn) of 500 to 500,000, which is graft-modified with at least one unsaturated compound selected from the group consisting of unsaturated epoxy compounds and unsaturated carboxylic acid compounds.

As the thermoplastic norbornene-based polymer, a ring-opening polymer of a norbornene-based monomer or a hydrogenated product thereof is used. From the viewpoints of heat resistance, durability, and electrical properties such as dielectric constant, a hydrogenated ring-opening polymer of a norbornene-based monomer is particularly preferred.

(1) Norbornene-Based Monomers The norbornene-based monomers, ring-opening polymers of norbornene-based monomers, and hydrogenated products thereof used in the present invention are not particularly limited, and known products such as those disclosed in Japanese Patent Application Laid-Open Nos. 3-14882 and 3-122137 can be used.

Norbornene-based monomers are known monomers disclosed in the above-mentioned publications, JP-A-2-227424, JP-A-2-276842, and the like, and examples thereof include polycyclic hydrocarbons having a norbornene structure; their alkyl-, alkenyl-, alkylidene-, or aromatic-substituted derivatives; polar group-substituted derivatives such as halogen, hydroxyl group, ester group, alkoxy group, cyano group, amide group, imide group, or silyl group; and alkyl-, alkenyl-, alkylidene-, or aromatic-substituted derivatives having these polar groups. Among these, polycyclic hydrocarbons having a norbornene structure and their alkyl-, alkenyl-, alkylidene-, or aromatic-substituted derivatives are preferred due to their excellent chemical resistance and moisture resistance.

Typical norbornene-based monomers for use in the present invention are represented by the formula (a): [In the formula, ^R1 to ^R8 are each independently a hydrogen atom, a hydrocarbon group, a halogen atom, an alkoxy group, an ester group, a cyano group, an amide group, an imide group, a silyl group, or a hydrocarbon group substituted with a polar group (i.e., a halogen atom, an alkoxy group, an ester group, a cyano group, an amide group, an imide group, or a silyl group). However, two or more of ^R5 to ^R8 may be bonded to each other to form a monocycle or polycycle, and this monocycle or polycycle may have a carbon-carbon double bond or form an aromatic ring. ^R5 and ^R6 , or ^R7 and ^R8 may be combined to form an alkylidene group.]

Examples of halogen atoms in formula (a) include fluorine, chlorine, bromine, and iodine atoms. Examples of hydrocarbon groups include alkyl groups having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms; alkenyl groups having 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms; cycloalkyl groups having 3 to 15 carbon atoms, preferably 3 to 8 carbon atoms; and aryl groups having 6 to 12 carbon atoms, preferably 6 to 8 carbon atoms. Examples of hydrocarbon groups substituted with polar groups include halogenated alkyl groups having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms. Alkylidene groups that are not substituted with polar groups are preferred for their high moisture resistance, and typically have 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms.

Specific examples of alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, n-amyl, n-hexyl, and decyl groups. Specific examples of alkenyl groups include vinyl, propenyl, butenyl, pentenyl, and hexenyl groups. Specific examples of aryl groups include phenyl, tolyl, xylyl, biphenyl, and naphthyl groups. Specific examples of alkylidene groups include methylidene, ethylidene, propylidene, and isopropylidene groups. Specific examples of ester groups include alkyl ester groups.

In formula (a), ^R1 to ^R4 are preferably hydrogen atoms or hydrocarbon groups when high moisture resistance is required. Two or more of ^R5 to ^R8 may be bonded to each other to form a monocycle or polycycle, and this monocycle or polycycle may have a carbon-carbon double bond or form an aromatic ring. In this case, the monocycle or polycycle may have a substituent (hydrocarbon group, polar group, or hydrocarbon group substituted with a polar group) as described above. However, in this case, when high moisture resistance is required, it is preferable that the monocycle or polycycle does not have a polar group.

Preferred examples of the norbornene-based monomer represented by the formula (a) include those represented by the formula (a1): Examples of the compound include compounds represented by the following formula:

In formula (a1), ^R9 to ^R20 are each independently a hydrogen atom, a hydrocarbon group, a halogen atom, an alkoxy group, an ester group (e.g., an alkyl ester group), a cyano group, an amide group, an imide group, a silyl group, or a hydrocarbon group substituted with a polar group (i.e., a halogen atom, an alkoxy group, an ester group, a cyano group, an amide group, an imide group, or a silyl group), and when high moisture resistance is required, a hydrogen atom or a hydrocarbon group is used. However, two or more of ^R17 to ^R20 may be bonded to each other to form a monocyclic or polycyclic ring, and this monocyclic or polycyclic ring may have a carbon-carbon double bond or form an aromatic ring. ^R17 and ^R18 , or ^R19 and ^R20 , may together form an alkylidene group. Of course, these monocyclic, polycyclic, or aromatic rings may have the above-mentioned substituents (hydrocarbon groups, polar groups, or hydrocarbon groups substituted with polar groups). However, in this case, if a high degree of moisture resistance is required, it is preferable that the compound does not have a polar group. Specific examples of these substituents are the same as those described above.

Other preferred examples of the norbornene-based monomer represented by the formula (a) include those represented by the formula (a2): Examples of the compound include compounds represented by the following formula:

In formula (a2), m is 0, 1, or 2, and when m is 0, a cyclopentane ring is formed. ^R21 to ^R32 are each independently a hydrogen atom, a hydrocarbon group, a halogen atom, an alkoxy group, an ester group (e.g., an alkyl ester group), a cyano group, an amide group, an imide group, a silyl group, or a hydrocarbon group substituted with a polar group (i.e., a halogen atom, an alkoxy group, an ester group, a cyano group, an amide group, an imide group, or a silyl group), and when high moisture resistance is required, a hydrogen atom or a hydrocarbon group is used. However, two or more of ^R29 to ^R32 may be bonded to each other to form a monocyclic or polycyclic ring, and this monocyclic or polycyclic ring may have a carbon-carbon double bond or form an aromatic ring. ^R29 and ^R30 , or ^R31 and ^R32 , may together form an alkylidene group. Furthermore, ^R30 and ^R31 may be bonded to form a double bond between the two carbon atoms to which ^R30 and ^R31 are bonded, respectively. Of course, these monocyclic, polycyclic, or aromatic rings may have the above-mentioned substituents (hydrocarbon groups, polar groups, or hydrocarbon groups substituted with polar groups). However, in this case, if high moisture resistance is required, those having no polar groups are preferred.

Specific examples of these substituents are the same as those mentioned above.

Specific examples of norbornene-based monomers include bicyclo[2.2.1]hept-2-ene derivatives and tetracyclo[4.4.0.1]hept-2-ene derivatives.^2,5．１^7,10]-3- Dodecene derivatives, hexacyclo[6.6.1.1^3,6．１^10,13．0^2,7．0^9,14 ]-4-heptadecene derivative, octacyclo[8.8.0.1^2,9．１^4,7．１^{11 ,18} . 1^13,16．0^3,8．0^12,17]-5-docosene derivatives, pentacyclo[6.6 . 1.1^3,6．0^2,7．0^9,14]-4-hexadecene derivatives, heptacyclo-5- eicosene derivatives, heptacyclo-5-heneicosene derivatives, tricyclo[4 . 3.0.1^2,5]-3-decene derivatives, tricyclo[4.4.0.1^2,5]-3-undecene derivatives, pentacyclo[6.5.1.1^3,6．0^2,7．0^9,13]-4 -pentadecene derivatives, pentacyclopentadecadiene derivatives, pentacyclo[ 7.4.0.1^2,5．１^9,12．0^8,13]-3-pentadecene derivatives, heptacyclo[8.7.0.1^3,6．１^10,17．１^12,15．0^2,7．0^11,16]-4-eicosene derivatives, nonacyclo[10.9.1.1^4,7．１^13,20．１^15,18．0^3,8．0^2,10．0^{12,2 1} . 0^14,19]-5-pentacosene derivatives, pentacyclo[8.4.0.1^2,5． １^9,12．0^8,13]-3-hexadecene derivatives, heptacyclo[8.8.0.1^{4, 7} . 1^11,18．１^13,16．0^3,8．0^12,17]-5-heneicosene derivatives, nonacyclo[10.10.1.1^5,8．１^14,21．１^16,19．0^2,11．0^4,9．0^13,22． 0^15,201,4-methano-1,4,4a,9a-tetrahydrofluorene derivatives, 1,4-methano-1,4,4a,5,10,10a-hexahydroanthracene derivatives, and cyclopentadiene-acenaphthylene adducts.

More specifically, for example, bicyclo[2.2.1]hept-2-ene derivatives such as bicyclo[2.2.1]hept-2-ene, 6-methylbicyclo[2.2.1]hept-2-ene, 5,6-dimethylbicyclo[2.2.1]hept-2-ene, 1-methylbicyclo[2.2.1]hept-2-ene, 6-ethylbicyclo[2.2.1]hept-2-ene, 6-n-butylbicyclo[2.2.1]hept-2-ene, 6-isobutylbicyclo[2.2.1]hept-2-ene, and 7-methylbicyclo[2.2.1]hept-2-ene; tetracyclo[4.4.0.1]hept-2-ene;^2,5．１^7,10]-3-dodecene, 8-methyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-ethyltetracyclo[4.4.0.1^2,5 . 1^7,10]-3-dodecene, 8-propyltetracyclo[4.4.0.1^2,5． １^7,10]-3-dodecene, 8-butyltertracyclo[4.4.0.1^2,5．１^{7,1 0} ]-3-dodecene, 8-isobutyltetracyclo[4.4.0.1^2,5．１^7,10 ]-3-dodecene, 8-hexyltetracyclo[4.4.0.1^2,5．１^7,10] -3-Dodecene, 8-Cyclohexyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-stearyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 5,10-dimethyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 2,10-dimethyl tetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8,9-dimethyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-ethyl- 9-methyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 11,12-dimethyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene , 2,7,9-trimethyltetracyclo[4.4.0.1^2,51^7,10]-3-dodecene, 9-ethyl-2,7-dimethyltetracyclo[4.4.0.1^2,5．１^{7 ,10} ]-3-dodecene, 9-isobutyl-2,7-dimethyltetracyclo[4. 4.0.1^2,5．１^7,10]-3-dodecene, 9,11,12-trimethyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 9-ethyl-11,1 2-dimethyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 9-isobutyl-11,12-dimethyltetracyclo[4.4.0.1^2,5．１^{7,1 0} ]-3-dodecene, 5,8,9,10-tetramethyltetracyclo[4.4. 0.1^2,5．１^7,10]-3-dodecene, 8-ethylidene-9-methyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-ethylidene-9-ethyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-ethylidene-9-isopropyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-ethylidene-9-butyltetracyclo[4.4.0.1^2,5．１^7,10 ]-3-dodecene, 8-n-propylidenetetracyclo[4.4.0.1^2,5． １^7,10]-3-dodecene, 8-n-propylidene-9-methyltetracyclo[4 . 4.0.1^2,5．１^7,10]-3-dodecene, 8-n-propylidene-9-ethyltetracyclo[4.4.0.1^2,5． １^7,10]-3-dodecene, 8-n-propylidene-9-isopropyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-n-propylidene-9-butyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-isopropylidenetetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-isopropylidene-9-methyltetracyclo[4.4.0.1^2,5．１^7,10 ]-3-dodecene, 8-isopropylidene-9-ethyltetracyclo[4.4. 0.1^2,5．１^7,10]-3-dodecene, 8-isopropylidene-9-isopropyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-isopropylidene-9-butyltetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-chlorotetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene , 8-bromotetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-fluorotetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8,9-dichlorotetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, and other tetracyclo[4.4.0.1]-3-dodecene.^2,5．１^7,10]-3-dodecene derivatives; hexacyclo[6.6.1.1^3,6．１^10,13．0^2,7．0^9,14]-4-heptadecene , 12-methylhexacyclo[6.6.1.1^3,6．１^10,13．0^2,7．0^9,14] -4-Heptadecene, 12-ethylhexacyclo[6.6.1.1^3,6．１^10,13 . 0^2,7．0^9,14]-4-heptadecene, 12-isobutylhexacyclo[6.6.1.1^3,6．１^10,13．0^2,7．0^9,14]-4-heptadecene, 1,6,10-trimethyl-12-isobutylhexacyclo[6.6.1.1^3,6．１^10,13． 0^2,7．0^9,14]-4-heptadecene, and other hexacyclo[6.6.1.1^3,6 . 1^10,13．0^2,7．0^9,14"-4-heptadecene derivative; octacyclo[8.8.0.1^2,9．１^4,7．１^11,18． １^13,16．0^3,8．0^12,17]-5-docosene, 15-methyloctacyclo[8.^2,9．１^4,7．１^11,18．１^13,16．0^3,8．0^12,17]-5-docosene, 15-ethyloctacyclo[8.8.0.1^2,9．１^4,7．１^11,18．１^13,16．0^3,8 . 0^12,17octacyclo[8.8.0.1]-5-docosene,^2,9．１^{4 ,7} . 1^11,18．１^13,16．0^3,8．0^12,17]-5-docosene derivative; pentacyclo [6.6.1.1^3,6．0^2,7．0^9,14]-4-Hexadecene, 1,3-dimethyl pentacyclo[6.6.1.1^3,6．0^2,7．0^9,14]-4-hexadecene, 1,6-dimethylpentacyclo[6.6.1.1^3,6．0^2,7．0^9,14]-4-hexadecene, 15,16-dimethylpentacyclo[6.6.1.1^3,6．0^2,7．0^{9, 14} ]-4-hexadecene, etc.^3,6．0^2,7．0^9,14 ]-4-Hexadecene derivative; Heptacyclo[8.7.0.1^2,9．１^4,7． １^11,17．0^3,8．0^12,16]-5-eicosene, heptacyclo[8.8.0.1^{2 ,9} . 1^4,7．１^11,18．0^3,8．0^12,17]-5-heneicosene, heptacyclo-5-eicosene derivatives or heptacyclo-5-heneicosene derivatives ; tricyclo[4.3.0.1^2,5]-3-decene, 2-methyltricyclo[4 . 3.0.1^2,5]-3-decene, 5-methyltricyclo[4.3.0.1^2,5] Tricyclo[4.3.0.1]-3-decene, etc.^2,5]-3-decene derivatives; Tricyclo[4.4.0.1^2,5]-3-undecene, 10-methyltricyclo [4.4.0.1^2,5]-3-undecene, and other tricyclo[4.4.0.1]-3-undecene.^{2 ,5} ]-3-undecene derivatives; pentacyclo[6.5.1.1^3,6．0^2,7．0^{9, 13} ]-4-pentadecene, 1,3-dimethylpentacyclo[6.5.1.1^3,6 . 0^2,7．0^9,13]-4-pentadecene, 1,6-dimethylpentacyclo[6.5.1.1^3,6．0^2,7．0^9,13]- 4-pentadecene, 14,15-dimethylpentacyclo[6.5.1.1^3,6． 0^2,7．0^9,13]-4-pentadecene, such as pentacyclo[6.5.1.1]-4-pentadecene,^3,6 . 0^2,7．0^9,13]-4-pentadecene derivatives; pentacyclo[6.5.1.1^{3 ,6} . 0^2,7．0^9,13]-4,10-pentadecadiene;^2,5．１^9,12．0^8,13]-3-pentadecene, methyl-substituted pentacyclo[7.4.0.1^2,5．１^9,12．0^8,13pentacyclo[7.4.0.1]-3-pentadecene,^2,5．１^9,12．0^8,13]-3-pentadecene derivatives; heptacyclo[8.7.0.1^3,6．１^10,17．１^12,15．0^2,7． 0^11,16]-4-eicosene, dimethyl-substituted heptacyclo[8.7.0.1^3,6． １^10,17．１^12,15．0^2,7．0^11,16]-4-eicosene, etc., heptacyclo[ 8.7.0.1^3,6．１^10,17．１^12,15．0^2,7．0^11,16-4-eicosene derivatives; nonacyclo[10.9.1.1^4,7．１^13,20．１^15,18．0^3,8．0^2,10． 0^12,21．0^14,9]-5-Pentacosene, trimethyl-substituted nonacyclo[10.9 . 1.1^4,7．１^13,20．１^15,18．0^3,8．0^2,10．0^12,21．0^14,19]-5-pentacosene, and other nonacyclo[10.9.1.1]-5-pentacosene^4,7．１^13,20．１^15,18．0^{3 ,8} . 0^2,10．0^12,21．0^14,19]-5-pentacosene derivative; pentacyclo[8 . 4.0.1^2,5．１^9,12．0^8,13]-3-hexadecene, 11-methylpentacyclo[8.4.0.1^2,5．１^9,12．0^8,13]-3-hexadecene, 11-ethyl-pentacyclo[8.4.0.1^2,5．１^9,12．0^8,13]-3-hexadecene, 10,11-dimethyl-pentacyclo[8.4.0.1^2,5．１^9,12．0^{8,1 3} ]-5-hexadecene, etc.^2,5．１^9,12．0^8,13 ]-3-hexadecene derivative; heptacyclo[8.8.0.1^4,7．１^11,18．１^13,16．0^3,8．0^12,17]-5-heneicosene, 15-methyl-heptacyclo[8.8.0.1^4,7．１^11,18 . 1^13,16．0^3,8．0^12,17"-5-heneicosene, trimethyl-heptacyclo[8.8.0.1^4,7．１^11,18．１^13,16．0^3,8．0^12,17]-5-hene Heptacyclo[8.8.0.1]e, etc.^4,7．１^11,18．１^13,16．0^3,8． 0^12,17]-5-heneicosene derivatives; nonacyclo[10.10.1.1^5,8． １^14,21．１^16,19．0^2,11．0^4,9．0^13,22．0^15,20]-6-, hexacosene , etc.^5,8．１^14,21．１^16,19．0^2,11．0^{4 ,9} . 0^13,22．0^15,20]-6-hexacosene derivatives; pentacyclo[6.5.1 .1^3,6．0^2,7．0^9,13]-4,11-pentadecadiene, methyl-substituted pentacyclo[6.5.1.1^3,6．0^2,7．0^9,13]-4,11-pentadecadiene, trimethyl-substituted pentacyclo[4.7.0.1^2,5．0^8,13．１^9,12]-3-pentadecene, pentacyclo[4.7.0.1^2,5．0^8,13．１^9,12]-3,10- Pentadecadiene, methyl-substituted pentacyclo[4.7.0.1^2,5．0^8,13．１^{9 ,12}]-3,10-Pentadecadiene, methyl-substituted heptacyclo[7.8.0. 1^3,6．0^2,7．１^10,17．0^11,16．１^12,15]-4-eicosene, trimethyl-substituted heptacyclo[7.8.0.1^3,6．0^2,7．１^10,17．0^11,16．１^12,15]- 4-Eicosene, tetramethyl-substituted heptacyclo[7.8.0.1^3,6．0^2,7． １^10,17．0^11,16．１^12,15]-4-eicosene, tricyclo[4.3.0.1^{2 ,5}]-3,7-decadiene (i.e., dicyclopentadiene), 2,3-dihydrodicyclopentadiene, 5-phenyl-bicyclo[2.2.1]hept-2-ene (i.e., 5-phenyl-2-norbornene), 5-methyl-5-phenyl-bicyclo[2.2.1]hept-2-ene, 5-benzyl-bicyclo[2.2.1]hept-2-ene, 5-tolyl-bicyclo[2.2.1]hept-2-ene, 5-(ethylphenyl)-bicyclo[2.2.1]hept-2-ene, 5-(isopropylphenyl)-bicyclo[2.2.1]hept-2-ene, 8-phenyl-tetracyclo[4.4.0.1^2,5 . 1^7,10]-3-dodecene, 8-methyl-8-phenyl-tetracyclo[4 . 4.0.1^2,5．１^7,10]-3-dodecene, 8-benzyl-tetracyclo[4 . 4.0.1^2,5．１^7,10]-3-dodecene, 8-tolyl-tetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-(ethylphenyl)-tetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-(isopropylphenyl)-tetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8,9-diphenyl-tetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-(biphenyl)-tetracyclo[4.4.0.1^2,5．１^7,10]-3-dodecene, 8-(β-naphthyl)-tetracyclo[4.4.0.1^2,5．１^7,10]- 3-dodecene, 8-(α-naphthyl)-tetracyclo[4.4.0.1^2,5．１^{7 ,10} ]-3-dodecene, 8-(anthracenyl)-tetracyclo[4.4.0. 1^2,5．１^7,10]-3-dodecene, 11-phenyl-hexacyclo[6.6.1 . 1^3,6．0^2,7．0^9,14]-4-heptadecene, 6-(α-naphthyl)-bicyclo[2.2.1]-hept-2-ene, 5-(anthracenyl)-bicyclo[2.2.1]-hept-2-ene, 5-(biphenyl)-bicyclo[2.2.1]-hept-2-ene, 5-(β-naphthyl)-bicyclo[2.2.1]-hept-2-ene, 5,6-diphenyl-bicyclo[2.2.1]-hept-2-ene, 9-(2-norbornene-5-yl)-carbazole, 1,4-methano-1,4,4a,4b,5,8,8a,9a-octadecane Hydrofluorenes: 1,4-methano-1,4,4a,9a such as 1,4-methano-1,4,4a,9a-tetrahydrofluorene, 1,4-methano-8-methyl-1,4,4a,9a-tetrahydrofluorene, 1,4-methano-8-chloro-1,4,4a,9a-tetrahydrofluorene, and 1,4-methano-8-bromo-1,4,4a,9a-tetrahydrofluorene. 1,4-methano-1,4,4a,9a-tetrahydrofluorenes; 1,4-methano-1,4,4a,9a-tetrahydrodibenzofurans; 1,4-methano-1,4,4a,9a-tetrahydrocarbazoles such as 1,4-methano-1,4,4a,9a-tetrahydrocarbazole and 1,4-methano-9-phenyl-1,4,4a,9a-tetrahydrocarbazole; 1,4-methano-1,4,4a 1,4-methano-1,4,4a,5,10,10a-hexahydroanthracene; 7,10-methano-6b,7,10,10a-tetrahydrofluoranes; compounds in which cyclopentadiene is further added to a cyclopentadiene-acenaphthylene adduct, such as 11,12-benzo-pentacyclo[6.5.1.1]a, ...^{3, 6} . 0^2,7．0^9,13]-4-pentadecene, 11,12-benzo-pentacyclo[ 6.6.1.1^3,6．0^2,7．0^9,14]-4-hexadecene, 14,15-benzo-heptacyclo[8.7.0.1^2,9．１^4,7．１^11,17．0^3,8．0^12,16]-5-eicosene, cyclopentadiene-acenaphthylene adduct, etc.

These norbornene-based monomers can be used alone or in combination of two or more.

As the molecular weight modifier, for example, α-olefins such as 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, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene; non-conjugated diolefins such as 1,4-hexadiene; and the like can be used in amounts up to about 10 mol %.

(2) Ring-Opening Polymerization A ring-opening polymer of a norbornene-based monomer can be obtained by ring-opening polymerizing at least one norbornene-based monomer using, as a ring-opening polymerization catalyst, a catalyst system consisting of a halide, nitrate, or acetylacetone compound of a metal such as ruthenium, rhodium, palladium, osmium, iridium, or platinum, and a reducing agent; or a catalyst system consisting of a halide or acetylacetone compound of a metal such as titanium, vanadium, zirconium, tungsten, or molybdenum, and an organoaluminum compound; in a solvent or without a solvent, usually at a polymerization temperature of −50° C. to 100° C. and a polymerization pressure of 0 to 50 kg/cm ² .

The addition of a third component to the catalyst system, such as molecular oxygen, alcohols, ethers, peroxides, carboxylic acids, acid anhydrides, acid chlorides, esters, ketones, nitrogen-containing compounds, sulfur-containing compounds, halogen-containing compounds, molecular iodine, or other Lewis acids, can enhance the polymerization activity and selectivity of ring-opening polymerization.

(3) Hydrogenation The hydrogenated ring-opening polymer of a norbornene-based monomer can be obtained by hydrogenating the ring-opening polymer with hydrogen in the presence of a hydrogenation catalyst according to conventional methods.

Examples of the hydrogenation catalyst include catalysts comprising a combination of a transition metal compound and an alkyl metal compound, such as combinations of cobalt acetate/triethylaluminum, nickel acetylacetonate/triisobutylaluminum, titanocene dichloride/n-butyllithium, zirconocene dichloride/sec-butyllithium, and tetrabutoxytitanate/dimethylmagnesium.

The hydrogenation reaction is typically carried out in an inert organic solvent. As the organic solvent, hydrocarbon solvents are preferred due to their excellent solubility in the hydrogenated product, and cyclic hydrocarbon solvents are more preferred. Examples of such hydrocarbon solvents include aromatic hydrocarbons such as benzene and toluene; aliphatic hydrocarbons such as n-pentane and hexane; alicyclic hydrocarbons such as cyclohexane and decalin; and ethers such as tetrahydrofuran and ethylene glycol dimethyl ether. Mixtures of two or more of these solvents can also be used. Typically, the same solvent as the polymerization reaction solvent is sufficient; the hydrogenation catalyst can be added directly to the polymerization reaction mixture and the reaction can be carried out.

The thermoplastic norbornene polymer used in the present invention preferably has high weather resistance and light degradation resistance, and therefore, it is preferable that the ring-opening polymer has unsaturated bonds in the main chain structure saturated at 95% or more, preferably 98% or more, and more preferably 99% or more. The aromatic ring structure may be hydrogenated, but from the viewpoint of heat resistance, it is desirable that 20% or more, preferably 30% or more, and preferably 40% or more remain. The unsaturated bonds in the main chain structure and the unsaturated bonds in the aromatic ring structure can be distinguished and recognized by ^1H -NMR analysis.

To mainly hydrogenate the unsaturated bonds in the main chain structure, it is desirable to carry out the hydrogenation reaction at a temperature of -20 to 120°C, preferably 0 to 100°C, more preferably 20 to 80°C, and under a hydrogen pressure of 0.1 to 50 kg/ ^cm2 , preferably 0.5 to 30 kg/ ^cm2 , more preferably 1 to 20 kg/ ^cm2 .

(4) Thermoplastic Norbornene-Based Polymers The thermoplastic norbornene-based polymers used in the present invention are ring-opening polymers of norbornene-based monomers or hydrogenated products thereof. Such thermoplastic norbornene-based polymers can typically be obtained by ring-opening polymerization of norbornene-based monomers represented by formula (a) above, followed by hydrogenation, if necessary.

Specifically, the formula (A) Examples of suitable polymers include those having repeating units represented by the following formula: In formula (A), R ¹ to R ⁸ are the same as those in formula (a). However, when the carbon-carbon double bond in the main chain is hydrogenated by hydrogenation, if there is a non-conjugated double bond in the side chain, the non-conjugated double bond is also hydrogenated. When there is an aromatic ring in the side chain, it is preferable from the viewpoint of heat resistance that some or all of the conjugated double bonds in the aromatic ring remain even after hydrogenation.

In formula (A), the symbol ... represents a single bond or a double bond. When the hydrogenation rate is high, at 99% or more, the carbon-carbon double bonds in the main chain are almost all single bonds. When hydrogenation is partial, single and double bonds coexist in the main chain.

When the norbornene-based monomer represented by the formula (a1) is subjected to ring-opening polymerization and, if necessary, hydrogenated, a compound represented by the formula (A1) A polymer having a repeating unit represented by the formula:

In formula (A1), ^R9 to ^R20 are the same as in formula (a1). However, when the carbon-carbon double bond in the main chain is hydrogenated by hydrogenation, if there is a non-conjugated double bond in the side chain, the non-conjugated double bond is also hydrogenated. When there is an aromatic ring in the side chain, it is preferable from the viewpoint of heat resistance that some or all of the conjugated double bond in the aromatic ring remain even after hydrogenation. In formula (A1), ... represents a single bond or a double bond.

When the norbornene-based monomer represented by the formula (a2) is subjected to ring-opening polymerization and, if necessary, hydrogenated, a compound represented by the formula (A2) A polymer having a repeating unit represented by the formula:

In formula (A2), m and ^R21 to ^R32 are the same as in formula (a2). However, when the carbon-carbon double bond in the main chain is hydrogenated by hydrogenation, if there is a non-conjugated double bond in the side chain, the non-conjugated double bond is also hydrogenated. When there is an aromatic ring in the side chain, it is preferable from the viewpoint of heat resistance that some or all of the conjugated double bond in the aromatic ring remain even after hydrogenation. In formula (A2), ... represents a single bond or a double bond.

The molecular weight of the thermoplastic norbornene polymer used is 500 to 500,000, preferably 3,000 to 300,000, and more preferably 5,000 to 250,000, as measured by gel permeation chromatography (GPC) using toluene as a solvent, in terms of polystyrene, or, if the norbornene polymer is insoluble in toluene, by GPC using cyclohexane as a solvent, in terms of polyisoprene.

If the number average molecular weight (Mn) of the norbornene polymer is too small, the mechanical strength will be poor. Conversely, if the number average molecular weight (Mn) is too large, the graft modification rate of the unsaturated compound selected from the group consisting of unsaturated epoxy compounds and unsaturated carboxylic acid compounds will not be increased sufficiently, and processability will also be reduced.

The molecular weight distribution of the thermoplastic norbornene polymer is not particularly limited, but when the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw/Mn) as calculated as polystyrene by GPC using toluene as a solvent is generally 4.0 or less, preferably 3.0 or less, and more preferably 2.5 or less, the mechanical strength is highly improved, and therefore it is preferred.

The glass transition temperature (Tg) of a thermoplastic norbornene-based polymer may be selected appropriately depending on the intended use, but is typically about 50 to 200°C as measured by a differential scanning calorimeter (DSC). A thermoplastic norbornene-based polymer with a high glass transition temperature is preferred because it minimizes the decrease in mechanical strength, particularly at high temperatures such as those used for mounting electronic components and reliability testing, and also provides excellent viscosity characteristics. However, even if the glass transition temperature is relatively low, the heat resistance can be sufficiently improved by using a modified polymer in combination with a crosslinking agent to form a crosslinked polymer.

(5) Graft Modification The graft monomer used in the present invention is an unsaturated compound selected from the group consisting of unsaturated epoxy compounds and unsaturated carboxylic acid compounds.

Examples of unsaturated epoxy compounds include glycidyl esters of unsaturated carboxylic acids such as glycidyl acrylate, glycidyl methacrylate, and glycidyl p-styrylcarboxylate; monoglycidyl esters or polyglycidyl esters of unsaturated polycarboxylic acids such as endo-cis-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic acid and endo-cis-bicyclo[2,2,1]hept-5-ene-2-methyl-2,3-dicarboxylic acid; unsaturated glycidyl ethers such as allyl glycidyl ether, 2-methylallyl glycidyl ether, glycidyl ether of o-allylphenol, glycidyl ether of m-allylphenol, and glycidyl ether of p-allylphenol; 2-(o-vinyl phenol) Examples of epoxy groups include 2-(o-allylphenyl)ethylene oxide, 2-(o-vinylphenyl)ethylene oxide, 2-(o-allylphenyl)ethylene oxide, 2-(o-vinylphenyl)propylene oxide, 2-(o-allylphenyl)propylene oxide, 2-(o-allylphenyl)propylene oxide, p-glycidylstyrene, 3,4-epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene, 3,4-epoxy-1-pentene, 3,4-epoxy-3-methyl-1-pentene, 5,6-epoxy-1-hexene, vinylcyclohexene monoxide, and allyl-2,3-epoxycyclopentyl ether. Among these, allyl glycidyl esters and allyl glycidyl ethers are preferred, and allyl glycidyl ethers are particularly preferred.

The unsaturated carboxylic acid compound may be an unsaturated carboxylic acid or a derivative thereof. Examples of such unsaturated carboxylic acids include acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, and nadic acid (endo-cis-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid). Derivatives of the above unsaturated carboxylic acids include unsaturated carboxylic acid anhydrides, unsaturated carboxylic acid halides, unsaturated carboxylic acid amides, unsaturated carboxylic acid imides, and ester compounds of unsaturated carboxylic acids. Specific examples of such derivatives include malenyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, and glycidyl maleate. Among these, unsaturated dicarboxylic acids or their anhydrides are preferred, with maleic acid, nadic acid, and their anhydrides being particularly preferred.

These grafting monomers can be used alone or in combination of two or more.

The modified thermoplastic norbornene polymer of the present invention can be produced by graft-modifying the above-described graft monomer and thermoplastic norbornene polymer using various conventional methods. For example, (1) a method of melting a thermoplastic norbornene polymer and adding a graft monomer to the polymer to perform graft polymerization, or (2) a method of dissolving a thermoplastic norbornene polymer in a solvent and then adding a graft monomer to the polymer to perform graft copolymerization, can be used. Furthermore, methods for producing modified thermoplastic norbornene polymers include a method of modifying an unmodified thermoplastic norbornene polymer by blending a graft monomer to the polymer to achieve a desired graft modification rate, and a method of preparing a graft-modified thermoplastic norbornene polymer with a high graft modification rate and then diluting the modified thermoplastic norbornene polymer with the unmodified thermoplastic norbornene polymer to produce a graft-modified thermoplastic norbornene polymer with a desired modification rate. Either of these production methods can be used in the present invention.

In order to efficiently graft copolymerize the graft monomer, it is usually preferable to carry out the reaction in the presence of a radical initiator.

As the radical initiator, for example, organic peroxides, organic peresters, etc. are preferably used. Specific examples of such radical initiators include benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(peroxidebenzoate)hexyne-3, 1,4-bis(tert-butylperoxyisopropyl)benzene, lauroyl peroxide, tert-butyl peracetate, 2,5-dimethyl-2,5-di(t Examples of suitable perfluorooctyl alcohols include 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl perbenzoate, tert-butyl perphenyl acetate, tert-butyl perisobutyrate, tert-butyl per-sec-octoate, tert-butyl perpiperate, cumyl perpiperate, and tert-butyl perdiethyl acetate.

Furthermore, in the present invention, an azo compound can also be used as a radical initiator. Specific examples of the azo compound include azobisisobutyronitrile and dimethylazoisobutyrate.

Among these, dialkyl peroxides such as benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxide)hexyne-3, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and 1,4-bis(tert-butylperoxyisopropyl)benzene are preferably used as radical initiators.

These radical initiators may be used alone or in combination of two or more. The amount of the radical initiator used is usually 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight, and more preferably 0.1 to 2.5 parts by weight, per 100 parts by weight of the unmodified thermoplastic norbornene polymer.

The graft modification reaction can be carried out according to a conventional method without any particular limitations. The reaction temperature is usually 0 to 400°C, preferably 60 to 350°C, and the reaction time is usually 1 minute to 24 hours, preferably 30 minutes to 10 hours.

(6) Modified Thermoplastic Norbornene Polymer The molecular weight of the modified thermoplastic norbornene polymer is, in terms of polystyrene, a number average molecular weight (Mn) measured by gel permeation chromatography (GPC) using toluene as a solvent. Alternatively, if the modified thermoplastic norbornene polymer is insoluble in toluene, the number average molecular weight (Mn) measured by GPC using cyclohexane as a solvent is, in terms of polyisoprene, in the range of 500 to 500,000, preferably 3,000 to 300,000, and more preferably 5,000 to 250,000.

For applications in which the modified thermoplastic norbornene polymer is prepared as a highly concentrated solution, a large amount of compounding ingredients is added, or the polymer is impregnated into a reinforcing substrate, the number average molecular weight (Mn) is typically in the range of 500 to 20,000, preferably 3,000 to 20,000, and more preferably 5,000 to 19,500.

On the other hand, when the modified thermoplastic norbornene polymer is used in applications such as an interlayer insulating film, the number average molecular weight (Mn) is usually more than 20,000, with the upper limit being 500,000 or less, preferably 300,000 or less, and more preferably 250,000 or less.

If the number-average molecular weight (Mn) of the modified thermoplastic norbornene polymer is too small, the mechanical strength will be poor. Conversely, if it is too large, the viscosity will increase when dissolved in a solvent, making it difficult to increase the solids concentration, including the compounding ingredients, and reducing processability. Neither of these is desirable.

The molecular weight distribution of the modified thermoplastic norbornene polymer may be appropriately selected depending on the intended use. However, the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw/Mn), as measured by GPC under the above conditions, is typically 4.0 or less, preferably 3.5 or less, and more preferably 2.5 or less, which is suitable for achieving particularly high mechanical strength. In most cases, Mw/Mn is 2.0 or less.

The graft modification ratio of the modified thermoplastic norbornene polymer used in the present invention is selected appropriately depending on the intended use, but is typically in the range of 10 to 100 mol%, preferably 15 to 50 mol%, and more preferably 15 to 35 mol%, based on the total number of monomer units in the polymer. When the graft modification ratio of the modified thermoplastic norbornene polymer is within this range, a high level of balance is achieved in electrical properties such as dielectric constant, adhesion to metals and silicon wafers, and uniform dispersion of compounding ingredients, which is preferable. If the graft modification ratio is too low, adhesion to other materials such as metal layers and silicon wafers will decrease, which will in turn decrease heat resistance and durability.

The graft modification rate is expressed by the following formula (1).

Graft modification rate (mol %) = (X/Y) x 100 (1) X: total number of moles of modifying groups in the polymer due to the grafted unsaturated compounds Y: total number of monomer units of the polymer (= weight average molecular weight of polymer/average molecular weight of monomers) X can be said to be the total number of moles of modified residues due to graft monomers, and can be measured by ¹ H-NMR. Y is equal to the weight average molecular weight (Mw) of the polymer/molecular weight of the monomer. In the case of copolymerization, the molecular weight of the monomer is the average molecular weight of the monomer.

The modified thermoplastic norbornene polymer of the present invention is a graft-modified polymer in which an unsaturated compound is grafted onto a thermoplastic norbornene polymer trunk polymer. The repeating unit of the grafted portion is determined by the type of graft monomer (unsaturated compound).

The modified thermoplastic norbornene polymer of the present invention has the following characteristics: (1) sufficiently excellent heat resistance and electrical properties such as dielectric constant, (2) the solution concentration can be sufficiently increased, (3) even high concentrations of compounding agents can be uniformly dispersed in the solution, and the number of compounding agents that can be uniformly dispersed can be increased, and (4) due to a high graft modification rate, prepregs, laminates, interlayer insulating films, overcoat films, etc. using the modified thermoplastic norbornene polymer have sufficiently excellent adhesion (peel strength) to other materials such as metals (metal foils, metal vapor-deposited films, metal wiring, etc.) and silicon wafers. Crosslinkable Polymer Composition The crosslinkable polymer composition of the present invention is characterized by containing at least the modified thermoplastic norbornene polymer and a crosslinking agent as essential components.

The crosslinking method for the crosslinkable polymer composition of the present invention is not particularly limited and can be carried out using, for example, heat, light, radiation, etc., and the type of crosslinking agent is appropriately selected depending on the crosslinking method. The use of the modified norbornene polymer provides good dispersibility for various crosslinking agents. In addition to the crosslinking agent, the crosslinkable polymer composition of the present invention can optionally contain a crosslinking aid, a flame retardant, other compounding agents, a solvent, etc.

(1) Crosslinking Agent The modified thermoplastic norbornene polymer of the present invention can be crosslinked, for example, by irradiation with radiation. However, a crosslinking method using a crosslinking agent is typically employed. Examples of crosslinking agents include, but are not limited to, organic peroxides, heat-activated crosslinking agents, and light-activated crosslinking agents.

Organic Peroxides Examples of organic peroxides include ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; peroxyketals such as 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane and 2,2-bis(t-butylperoxy)butane; hydroperoxides such as t-butyl hydroperoxide and 2,5-dimethylhexane-2,5-dihydroperoxide; dialkyl peroxides such as dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, and α,α'-bis(t-butylperoxy-m-isopropyl)benzene; diacyl peroxides such as octanoyl peroxide and isobutyryl peroxide; and peroxyesters such as peroxydicarbonate. Among these, dialkyl peroxides are preferred in terms of the performance of the resin after crosslinking, and the type of alkyl group may be varied depending on the molding temperature.

The organic peroxides can be used alone or in combination of two or more. The amount of organic peroxide to be added is usually 0.001 to 30 parts by weight, preferably 0.01 to 25 parts by weight, and more preferably 1 to 20 parts by weight, per 100 parts by weight of the modified thermoplastic norbornene polymer. When the amount of organic peroxide is within this range, a high level of balance is achieved in the crosslinkability and the electrical properties, chemical resistance, water resistance, and other properties of the crosslinked product, and this is preferred.

Crosslinking Agents That Produce an Effect When Produced by Heat The crosslinking agent that produces an effect when produced by heat is not particularly limited as long as it can undergo a crosslinking reaction when heated, and examples thereof include diamines, triamines, or higher aliphatic polyamines, alicyclic polyamines, aromatic polyamine bisazides, acid anhydrides, dicarboxylic acids, polyhydric phenols, and polyamides. Specific examples include aliphatic polyamines such as hexamethylenediamine, triethylenetetramine, diethylenetriamine, and tetraethylenepentamine; alicyclic polyamines such as diaminocyclohexane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0 ^2,6 ]decane; 1,3-(diaminomethyl)cyclohexane, menthenediamine, isophoronediamine, N-aminoethylpiperazine, bis(4-amino-3-methylcyclohexyl)methane, and bis(4-aminocyclohexyl)methane; 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, α,α′-bis(4- aromatic polyamines such as 4,4-bis(4-aminophenyl)-1,3-diisopropylbenzene, α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, 4,4'-diaminodiphenylsulfone, and metaphenylenediamine; Bisazides such as 4'-azidobenzal-4-methyl-cyclohexanone, 4,4'-diazidodiphenylsulfone, 4,4'-diazidodiphenylmethane, and 2,2'-diazidostilbene; acid anhydrides such as phthalic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, nadic anhydride, 1,2-cyclohexanedicarboxylic acid, and maleic anhydride-modified polypropylene; dicarboxylic acids such as fumaric acid, phthalic acid, maleic acid, trimellitic acid, and himic acid; phenol novolac resins, cresol novolac polyhydric phenols such as acrylic resins; polyhydric alcohols such as tricyclodecanediol, diphenylsilanediol, ethylene glycol and its derivatives, diethylene glycol and its derivatives, and triethylene glycol and its derivatives; and polyamides such as nylon-6, nylon-66, nylon-610, nylon-11, nylon-612, nylon-12, nylon-46, methoxymethylated polyamide, polyhexamethylenediamine terephthalamide, and polyhexamethylene isophthalamide.

These may be used alone or in combination. Among these, aromatic polyamines, acid anhydrides, polyhydric phenols, and polyhydric alcohols are preferred because they provide excellent heat resistance, mechanical strength, adhesion, and dielectric properties (low dielectric constant, low dielectric dissipation factor) to the crosslinked product. Of these, 4,4-diaminodiphenylmethane (aromatic polyamines) and polyhydric phenols are particularly preferred.

The amount of the crosslinking agent is not particularly limited, but is typically in the range of 0.001 to 30 parts by weight, preferably 0.01 to 25 parts by weight, and more preferably 1 to 20 parts by weight, per 100 parts by weight of the modified thermoplastic norbornene polymer, from the viewpoints of efficient crosslinking, improved physical properties of the resulting crosslinked product, and economic efficiency. If the amount of crosslinking agent is too small, crosslinking will be difficult to achieve, and sufficient heat resistance and solvent resistance will not be obtained. If the amount of crosslinking agent is too large, the crosslinked resin will have reduced properties such as water absorption and dielectric properties, which is undesirable. Therefore, when the amount is within the above range, these properties are well balanced, making this an ideal range.

If necessary, a crosslinking accelerator (curing accelerator) can be added to increase the efficiency of the crosslinking reaction.

Examples of curing accelerators include amines such as pyridine, benzyldimethylamine, triethanolamine, triethylamine, and imidazoles. These are added to adjust the crosslinking rate and improve the efficiency of the crosslinking reaction. The amount of the curing accelerator is not particularly limited, but is typically used in the range of 0.1 to 30 parts by weight, preferably 1 to 20 parts by weight, per 100 parts by weight of the thermoplastic norbornene polymer. When the amount of the curing accelerator is within this range, a high level of balance is achieved between the crosslink density, the dielectric properties, and the water absorption rate, making this preferable. Imidazoles are particularly preferable due to their excellent dielectric properties.

Photo-activated crosslinking agents (curing agents) are photoreactive substances that react with modified thermoplastic norbornene polymers to form crosslinked compounds upon exposure to actinic rays such as g-rays, h-rays, and i-rays, ultraviolet rays, far ultraviolet rays, x-rays, and electron beams. Examples include aromatic bisazide compounds, photoamine generators, and photoacid generators.

Specific examples of aromatic bisazide compounds include 4,4'-diazidochalcone, 2,6-bis(4'-azidobenzal)cyclohexanone, 2,6-bis(4'-azidobenzal)4-methylcyclohexanone, 4,4'-diazidodiphenyl sulfone, 4,4'-diazidobenzophenone, 4,4'-diazidodiphenyl, 2,7-diazidofluorene, and 4,4'-diazidophenylmethane. These compounds may be used alone or in combination.

Specific examples of photoamine generators include o-nitrobenzyloxycarbonylcarbamate, 2,6-dinitrobenzyloxycarbonylcarbamate, and α,α-dimethyl-3,5-dimethoxybenzyloxycarbonylcarbamate derivatives of aromatic or aliphatic amines. More specific examples include o-nitrobenzyloxycarbonylcarbamate derivatives of aniline, cyclohexylamine, piperidine, hexamethylenediamine, triethylenetetraamine, 1,3-(diaminomethyl)cyclohexane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, phenylenediamine, and the like. These may be used alone or in combination.

The photoacid generator is a substance that generates a Bronsted acid or a Lewis acid upon irradiation with actinic rays, and examples thereof include onium salts, halogenated organic compounds, quinone diazide compounds, α,α-bis(sulfonyl)diazomethane compounds, α-carbonyl-α-sulfonyl-diazomethane compounds, sulfone compounds, organic acid ester compounds, organic acid amide compounds, and organic acid imide compounds. These compounds that can be cleaved to generate an acid upon irradiation with actinic rays may be used alone or in combination of two or more.

Other photocrosslinking agents include, for example, benzoin alkyl ether compounds such as benzoin ethyl ether and benzoin isobutyl ether; benzophenone compounds such as benzophenone, methyl orthobenzoyl benzoate, and 4,4'-dichlorobenzophenone; benzyl compounds such as dibenzyl and benzyl methyl ketal; 2,2-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, 1,1-dichloroacetophenone, 2,2-diethoxyacetophenone, and 4'-phenoxyacetophenone. Examples of suitable organic compounds include acetophenone compounds such as 2-2,2-dichloroacetophenone; thioxanthone compounds such as 2-chlorothioxanthone, 2-methylthioxanthone, and 2-isopropylthioxanthone; anthraquinone compounds such as 2-ethylanthraquinone, 2-chloroanthraquinone, and naphthoquinone; propiophenone compounds such as 2-hydroxy-2-methylpropiophenone and 4'-dodecyl-2-hydroxy-2-methylpropiophenone; and organic acid metal salts such as cobalt octenate, cobalt naphthenate, manganese octenate, and manganese naphthenate.

The amount of these photoreactive compounds to be added is not particularly limited, but is typically in the range of 0.001 to 30 parts by weight, preferably 0.01 to 25 parts by weight, and more preferably 1 to 20 parts by weight, per 100 parts by weight of the polymer, from the viewpoints of efficient reaction with the modified thermoplastic norbornene polymer, not impairing the physical properties of the resulting crosslinked resin, and economy. If the amount of photoreactive substance added is too small, crosslinking is difficult to occur, and sufficient heat resistance and solvent resistance cannot be obtained. If the amount is too large, the water absorption and dielectric properties of the crosslinked resin are reduced, which is undesirable. Therefore, when the amount is within the above range, these properties are well balanced, making this preferable.

(2) Crosslinking Auxiliary Agent In the present invention, the use of a crosslinking auxiliary agent is preferred because it can further enhance crosslinking and the dispersibility of compounding ingredients.

The crosslinking aid used in the present invention is not particularly limited, and may be a known one disclosed in, for example, JP-A-62-34924. Examples include oxime/nitroso-based crosslinking aids such as quinone dioxime, benzoquinone dioxime, and p-nitrosophenol; maleimide-based crosslinking aids such as N,N-m-phenylene bismaleimide; allyl-based crosslinking aids such as diallyl phthalate, triallyl cyanurate, and triallyl isocyanurate; methacrylate-based crosslinking aids such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; and vinyl-based crosslinking aids such as vinyltoluene, ethylvinylbenzene, and divinylbenzene. Among these, allyl-based crosslinking aids and methacrylate-based crosslinking aids are preferred because they are easily dispersed uniformly.

The amount of crosslinking aid added is selected appropriately depending on the type of crosslinking agent, but is typically 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, per 1 part by weight of crosslinking agent. If the amount of crosslinking aid added is too small, crosslinking will be difficult to occur. Conversely, if the amount added is too large, the electrical properties, water resistance, moisture resistance, etc. of the crosslinked resin may be reduced.

(3) Flame Retardant Although a flame retardant is not a required component, its addition is preferred when using the modified thermoplastic norbornene polymer composition for electronic components. There are no particular restrictions on the flame retardant, but it is preferable that it does not decompose, denature, or deteriorate when exposed to the crosslinking agent (curing agent).

Various chlorine- and bromine-based flame retardants can be used as halogen-based flame retardants. However, from the perspectives of flame retardancy, heat resistance during molding, dispersibility in resin, and effect on the physical properties of the resin, hexabromobenzene, pentabromoethylbenzene, hexabromobiphenyl, decabromodiphenyl, hexabromodiphenyl oxide, octabromodiphenyl oxide, decabromodiphenyl oxide, pentabromocyclohexane, tetrabromobisphenol A and its derivatives [e.g., tetrabromobisphenol A-bis(hydroxyethyl ether), tetrabromobisphenol A-bis(2,3-dibromopropyl ether), tetrabromobisphenol A-bis(bromoethyl ether), tetrabromobisphenol A-bis(allyl ether)], tetrabromobisphenol S and its derivatives [e.g., tetrabromobisphenol S-bis(hydroxyethyl ether), tetrabromobisphenol S-bis(allyl ether)], etc. 2,3-dibromopropyl ether, etc.), tetrabromophthalic anhydride, phthalic acid and its derivatives [e.g., tetrabromophthalimide, ethylene bis(tetrabromophthalimide, etc.)], ethylene bis(5,6-dibromonorbornene)-2,3-dicarboximide, tris-(2,3-dibromopropyl-1)-isocyanurate, Diels-Alder adducts of hexachlorocyclopentadiene, tribromophenyl glycidyl ether, tribromophenyl acrylate Preferably, brominated polyethersulfones, such as ethylene bis(tribromophenyl)ether, ethylene bis(pentabromophenyl)ether, tetradecabromodiphenoxybenzene, brominated polystyrene, brominated polyphenylene oxide, brominated epoxy resin, brominated polycarbonate, polypentabromobenzyl acrylate, octabromonaphthalene, hexabromocyclododecane, bis(tribromophenyl)fumaramide, and N-methylhexabromodiphenylamine are used.

These flame retardants can be used alone or in combination of two or more. The amount of the flame retardant added is usually 3 to 150 parts by weight, preferably 10 to 140 parts by weight, and particularly preferably 15 to 120 parts by weight, per 100 parts by weight of the modified thermoplastic norbornene polymer.

To more effectively utilize the flame retardant effect of the flame retardant, antimony-based flame retardant aids such as antimony trioxide, antimony pentoxide, sodium antimonate, and antimony trichloride can be used. These flame retardant aids are typically used in a ratio of 1 to 30 parts by weight, and preferably 2 to 20 parts by weight, per 100 parts by weight of the flame retardant.

(4) Filler The crosslinkable polymer composition of the present invention may contain a filler, particularly for the purposes of improving mechanical strength (toughness) and reducing the linear expansion coefficient. Examples of fillers include inorganic and organic fillers.

Inorganic fillers are not particularly limited, but examples include calcium carbonate (light calcium carbonate, heavy or micronized calcium, special calcium-based fillers), clay (aluminum silicate; nepheline syenite micropowder, calcined clay, silane-modified clay), talc, silica, alumina, diatomaceous earth, silica sand, pumice powder, pumice balloons, slate powder, mica powder, asbestos, alumina colloid (alumina sol), alumina white, aluminum sulfate, barium sulfate, lithopone, calcium sulfate, molybdenum disulfide, and graphite. ), glass fiber, glass beads, glass flakes, foam glass beads, fly ash spheres, hollow volcanic glass bodies, synthetic inorganic hollow bodies, single crystal potassium titanate, carbon fiber, hollow carbon spheres, anthracite powder, artificial cryolite, titanium oxide, magnesium oxide, basic magnesium carbonate, dolomite, potassium titanate, calcium sulfite, mica, asbestos, calcium silicate, montmorillonite, bentonite, graphite, aluminum powder, molybdenum sulfide, boron fiber, silicon carbide fiber, etc.

Examples of organic fillers include polyethylene fibers, polypropylene fibers, polyester fibers, polyamide fibers, fluorine fibers, ebonite powder, thermosetting resin hollow spheres, saran hollow spheres, shellac, wood flour, cork powder, polyvinyl alcohol fibers, cellulose powder, and wood pulp.

(5) Other Compounding Agents Other compounding agents, such as heat stabilizers, weather stabilizers, leveling agents, antistatic agents, slip agents, antiblocking agents, antifogging agents, lubricants, dyes, pigments, natural oils, synthetic oils, and waxes, can be added to the crosslinkable polymer composition of the present invention in appropriate amounts, as needed.

Specific examples include phenolic antioxidants such as tetrakis[methylene-3(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane, β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid alkyl ester, and 2,2'-oxamidobis[ethyl-3(3,5-di-t-butyl-4-hydroxyphenyl)propionate]; phosphorus-based stabilizers such as trisnonylphenyl phosphite, tris(2,4-di-t-butylphenyl)phosphite, and tris(2,4-di-t-butylphenyl)phosphite; and fat stabilizers such as zinc stearate, calcium stearate, and calcium 12-hydroxystearate. Examples of suitable additives include fatty acid metal salts; polyhydric alcohol fatty acid esters such as glycerin monostearate, glycerin monolaurate, glycerin distearate, pentaerythritol monostearate, pentaerythritol distearate, and pentaerythritol tristearate; synthetic hydrotalcite; amine-based antistatic agents; paint leveling agents such as fluorine-based nonionic surfactants, special acrylic resin leveling agents, and silicone leveling agents; coupling agents such as silane coupling agents, titanate coupling agents, aluminum coupling agents, and zircoaluminate coupling agents; plasticizers; and colorants such as pigments and dyes.

These ingredients can be used alone or in combination of two or more. The mixing ratio can be determined appropriately depending on the function and purpose of each ingredient.

To adjust the mechanical properties and flexibility, different thermoplastic resins such as polycarbonate, polystyrene, polyphenylene sulfide, polyetherimide, polyester, polyamide, polyarylate, and polysulfone; elastomers, rubbery polymers, and the like may be blended.

(6) Solvent In the present invention, the modified thermoplastic norbornene polymer can be dissolved in a solvent to prepare an impregnation solution for a prepreg, to produce a sheet (film) by solution casting, or to form a coating by coating.

When a solvent is used to dissolve the modified thermoplastic norbornene polymer, examples of the solvent include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; aliphatic hydrocarbons such as n-pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclohexane; and halogenated hydrocarbons such as chlorobenzene, dichlorobenzene, and trichlorobenzene.

The solvent is used in an amount sufficient to uniformly dissolve or disperse the modified thermoplastic norbornene polymer and the other components blended as necessary. The crosslinkable polymer composition of the present invention , such as a molded article, prepreg, laminate, or interlayer insulating film , can be molded into a desired shape and then crosslinked to form a crosslinkable molded article. The crosslinkable polymer composition can be molded by dissolving it in a solvent and molding it, or by melting it at a temperature that does not cause crosslinking or at a sufficiently slow crosslinking rate, so as to prevent deterioration of moldability due to crosslinking during molding. Specifically, the norbornene polymer composition dissolved in a solvent is cast and the solvent is removed, and the composition is molded into a sheet, or by impregnating a substrate and molding it.

The crosslinkable polymer composition of the present invention can be molded into various molded parts by various molding methods, such as a method of processing the composition in a thermoplastic resin state into a molded product by injection molding, press molding, compression molding, etc., a method of dissolving the composition in an organic solvent, forming a molded product by potting or molded molding while removing the solvent, and then curing the molded product, or a method of forming a thermosetting molded product by transfer molding, etc.

Furthermore, the crosslinkable polymer composition of the present invention can form a film by a coating method.

(1) Prepreg Prepreg, a specific example of a crosslinked molded article, is produced by uniformly dissolving or dispersing a modified thermoplastic norbornene polymer, a crosslinking agent, and various compounding ingredients in a solvent such as toluene, cyclohexane, or xylene. The resulting mixture is then impregnated with a reinforcing substrate and dried to remove the solvent. Generally, prepreg thicknesses of approximately 50 to 500 μm are preferred.

The amount of solvent used is adjusted so that the solids concentration is generally 1 to 90% by weight, preferably 5 to 85% by weight, and more preferably 10 to 80% by weight.

Examples of reinforcing substrates that can be used include paper substrates (linter paper, kraft paper, etc.), glass substrates (glass cloth, glass mat, glass paper, quartz fiber, etc.), and synthetic resin fiber substrates (polyester fiber, aramid fiber, etc.). These reinforcing substrates may be surface-treated with a treatment agent such as a silane coupling agent. These reinforcing substrates can be used alone or in combination of two or more.

The amount of the modified thermoplastic norbornene polymer composition relative to the reinforcing substrate is appropriately selected depending on the intended use, but is typically in the range of 1 to 90% by weight, preferably 10 to 60% by weight, relative to the reinforcing substrate.

(2) Sheets The method for producing sheets is not particularly limited, but a casting method is typically used. For example, the crosslinkable polymer composition of the present invention is dissolved or dispersed in a solvent such as toluene, xylene, or cyclohexane to a solids concentration of approximately 5 to 50% by weight, then cast or coated onto a smooth surface. The solvent is removed by drying or other methods, and the sheet is then peeled off from the smooth surface to obtain a sheet. When removing the solvent by drying, it is preferable to select a method that does not cause foaming due to rapid drying. For example, the solvent can be evaporated to a certain extent at a low temperature, and then the temperature can be raised to fully evaporate the solvent.

The smooth surface can be a mirror-finished metal plate or a resin carrier film. When using a resin carrier film, the solvent and drying conditions should be determined taking into account the solvent resistance and heat resistance of the carrier film material.

Sheets obtained by the casting method generally have a thickness of about 10 μm to 1 mm. These sheets can be crosslinked to be used as interlayer insulating films, moisture-proof films, etc. They can also be used to produce the laminates described below.

(3) Laminates: A laminate is formed by stacking multiple sheets of the prepreg and/or uncrosslinked sheet described above, and then heat-compressing and crosslinking them to a required thickness. When the laminate is used as a circuit board, a circuit is formed by, for example, laminating a conductive wiring layer made of metal foil or the like, or by surface etching or the like. The conductive wiring layer may be laminated not only on the outer surface of the finished laminate, but also inside the laminate depending on the purpose. To prevent warping during secondary processing such as etching, it is preferable to laminate the layers symmetrically. For example, the surfaces of the stacked prepregs and/or sheets are heated to a heat-fusion temperature or higher depending on the modified thermoplastic norbornene polymer used, typically about 150 to 300°C, and pressurized at about 30 to 80 kgf/ ^cm2 to crosslink and heat-fuse the layers to obtain a laminate.

Other methods for applying metals to these insulating layers or substrates include evaporation, electroplating, sputtering, ion plating, spraying, and layering. Commonly used metals include copper, nickel, tin, silver, gold, aluminum, platinum, titanium, zinc, and chromium. Copper is most frequently used in wiring boards.

(4) Crosslinking In the present invention, the molded article is crosslinked, either singly or in layers, to obtain a crosslinked molded article. Crosslinking can be achieved by conventional methods, including irradiation, heating above a certain temperature when an organic peroxide is added, and irradiation with ultraviolet or other light when a photocrosslinking agent is added. Among these, the crosslinking method involving the addition of an organic peroxide and heating is preferred because it is easy to perform.

The temperature at which the crosslinking reaction occurs is determined primarily by the combination of organic peroxide and crosslinking coagent, but crosslinking is typically achieved by heating to a temperature of 80 to 350°C, preferably 120 to 300°C, and more preferably 150 to 250°C. The crosslinking time is preferably approximately four times the half-life of the organic peroxide, typically 5 to 120 minutes, preferably 10 to 90 minutes, and more preferably 20 to 60 minutes. When a thermally activated crosslinking agent (curing agent) is used as the crosslinking agent, crosslinking is achieved by heating. When a photocrosslinking agent is used as the crosslinking agent, crosslinking can be achieved by light irradiation. When crosslinkable molded articles are laminated and crosslinked, heat fusion and crosslinking occur between the layers, resulting in an integrated crosslinked molded article.

(5) Crosslinked Molded Products Examples of the crosslinked molded products of the present invention include laminates, circuit boards, interlayer insulating films, and moisture-proof coating films. The crosslinked molded products of the present invention typically have a water absorption rate of 0.03% or less, a dielectric constant and a dielectric dissipation factor at 1 MHz of 2.0 to 4.0 and 0.005 to 0.0005, respectively, and are superior in moisture resistance and electrical properties to conventional thermosetting resin molded products. The heat resistance of the crosslinked molded products of the present invention is equivalent to that of conventional thermosetting resin molded products. Even when a copper foil-laminated laminate is contacted with solder at 260°C for 30 seconds or with solder at 300°C for ¹ minute, no abnormalities such as peeling or blisters of the metal layer, such as copper foil, are observed. Furthermore, the crosslinked molded products of the present invention typically have an excellent peel strength from copper foil of approximately 1.4 to 2.7 kg/cm², which is significantly improved compared to conventional thermoplastic norbornene resins. For these reasons, the crosslinked molded products of the present invention are preferred as circuit boards.

Molded articles obtained by molding the crosslinkable polymer composition of the present invention as a thermoplastic resin are useful for electronic components such as connectors, relays, and capacitors; injection-molded sealing parts for semiconductor elements such as transistors, ICs, and LSIs; and optical lens barrels, polygon mirrors, and Fθ mirrors.

When the crosslinkable polymer composition of the present invention is used in a dissolved state in an organic solvent, it is effective for applications such as potting for semiconductor devices and as a sealing material for medium-sized devices.

When the crosslinkable polymer composition of the present invention is used as a transfer molding material, it is effective as a packaging (sealing) material for semiconductor devices, etc.

The crosslinkable polymer composition of the present invention can be used in the form of a film or membrane. When used as a film, the crosslinkable polymer composition may be dissolved in an organic solvent and then pre-formed into a film by a casting method or the like, or the crosslinkable polymer composition may be coated with the solution and then the solvent removed to form an overcoat film. Specifically, the crosslinkable polymer composition is useful as, for example, an insulating sheet for laminates, an interlayer insulating film, a liquid encapsulating material for semiconductor elements, an overcoat material, and the like.

<Examples> The present invention will be explained in detail below using examples and comparative examples. The physical properties were measured as follows:

(1) The glass transition temperature was measured by differential scanning calorimetry (DSC).

(2) Unless otherwise specified, molecular weights were measured as polystyrene equivalents by gel permeation chromatography (GPC) using toluene as a solvent.

(3) The hydrogenation rates of the main chain and side chain were measured by ¹ H-NMR.

(4) The total number of moles of modified residues of the unsaturated epoxy compound and unsaturated carboxylic acid compound was measured by ¹ H-NMR, and the graft modification rate was calculated according to the above formula.

(5) Flame retardancy was measured according to the US UL-94 test standard.

(6) The dielectric constant and dielectric loss tangent were measured at 1 MHz in accordance with JIS K6911.

(7) The copper foil peel strength was measured by taking a test piece 20 mm wide and 100 mm long from the resin laminate, making a 10 mm-wide parallel notch on the copper foil surface, and then using a tensile tester, continuously peeling the copper foil in a direction perpendicular to the surface at a rate of 50 mm/min. The minimum stress was recorded.

(8) Adhesion was evaluated by a cross-hatch peel strength test in accordance with JIS K5400.

(9) Durability was evaluated by leaving the product at 90°C and 95% relative humidity for 1,000 hours and observing any abnormalities in appearance such as blisters, corrosion of copper, discoloration, etc.

(10) Heat resistance was evaluated by inspecting the appearance after contact with 300°C solder for 1 minute and judging according to the following criteria:

Good: No peeling or swelling, Bad: Peeling or swelling is observed.

Example 1: 5 g of 8-ethyltetracyclo[ ^{4.4.0.12,5.17,10} ]-3-dodecene (i.e., 6-ethyl-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene; hereinafter abbreviated as ETD) and 120 g of toluene were added to a 1-L flask purged with nitrogen. 0.287 mmol of triisobutylaluminum and 0.287 mmol of isobutyl alcohol were added as polymerization catalysts, and ^3.83 mmol of 1-hexene was added as a molecular weight modifier. 0.057 mmol of tungsten hexachloride was added to the flask, and the mixture was stirred at 40°C for 5 minutes. Subsequently, 45 g of ETD and 0.086 mmol of tungsten hexachloride were continuously added dropwise to the system over approximately 30 minutes. After the completion of the dropwise addition, the mixture was stirred for an additional 30 minutes to complete the polymerization.

The polymerization reaction mixture was transferred to a 1-liter autoclave, and 160 g of toluene was added. A mixture of 0.5 g of nickel acetylacetonate and 5.15 g of a 30 wt % toluene solution of triisobutylaluminum was then added. The reactor was purged with hydrogen and then heated to 80°C with stirring. Once the temperature stabilized, the hydrogen pressure was increased to 30 kg/ ^cm2 , and the reaction was continued for 3 hours while replenishment of hydrogen consumed during the reaction was continued. Next, 4.2 g of water and 2.5 g of activated alumina (surface area 320 ^cm2 /g, pore volume 0.8 ^cm3 /g, average particle size 15 μm, Neobead D powder, manufactured by Mizusawa Chemical Industries, Ltd.) were added, and the mixture was stirred at 80°C for 1 hour. After filtering to remove the solids, the hydrogenation reaction mixture was poured into 3 liters of isopropyl alcohol to precipitate the resin, which was then filtered and recovered. The recovered resin was dried at 100°C and 1 Torr or less for 48 hours.

50 parts by weight of the resulting polymer were mixed with 30 parts by weight of allyl glycidyl ether, 3.0 parts by weight of dicumyl peroxide, and 120 parts by weight of tert-butylbenzene, and the mixture was reacted in an autoclave at 150°C for 3 hours. The reaction solution was then coagulated and dried in the same manner as above to obtain epoxy-modified polymer (A). The synthesis results are shown in Table 1.

[Example 2] Epoxy-modified polymer (B) was obtained in the same manner as in Example 1, except that 3.83 mmol of 1-hexene was replaced with 5.75 mmol. The synthesis results are shown in Table 1.

[Example 3] A maleic anhydride-modified polymer (C) was obtained in the same manner as in Example 1, except that allyl glycidyl ether was replaced with maleic anhydride. The synthesis results are shown in Table 1.

Example 4 A maleic anhydride-modified polymer (D) was obtained in the same manner as in Example 1, except that 3.83 mmol of 1-hexene was replaced with 5.75 mmol, and allyl glycidyl ether was replaced with maleic anhydride. The synthesis results are shown in Table 1.

[Example 5] An epoxy-modified polymer (E) was obtained in the same manner as in Example 1, except that ETD was replaced with tricyclo[4.3.2.12,5] ^-3,7 -decadiene (i.e., dicyclopentadiene; hereinafter abbreviated as DCP), 30 parts by weight of allyl glycidyl ether was replaced with 100 parts by weight, and 3.0 parts by weight of dicumyl peroxide was replaced with 10 parts by weight. The synthesis results are shown in Table 1.

Example 6 Epoxy-modified polymer (F) was obtained in the same manner as in Example 1, except that the amount of 1-hexene was changed from 3.83 mmol to 5.75 mmol, ETD was changed to DCP, allyl glycidyl ether was changed from 30 parts by weight to 100 parts by weight, and dicumyl peroxide was changed from 3.0 parts by weight to 10 parts by weight. The synthesis results are shown in Table 1.

Example 7 A maleic anhydride-modified polymer (G) was obtained in the same manner as in Example 1, except that ETD was replaced with DCP, 30 parts by weight of allyl glycidyl ether was replaced with 100 parts by weight of maleic anhydride, and 3.0 parts by weight of dicumyl peroxide was replaced with 10 parts by weight. The synthesis results are shown in Table 1.

Example 8 A maleic anhydride-modified polymer (H) was obtained in the same manner as in Example 1, except that 3.83 mmol of 1-hexene was replaced with 5.75 mmol, ETD was replaced with DCP, 30 parts by weight of allyl glycidyl ether was replaced with 100 parts by weight of maleic anhydride, and 3.0 parts by weight of dicumyl peroxide was replaced with 10 parts by weight. The synthesis results are shown in Table 1.

Example 9 Epoxy-modified polymer (I) was obtained in the same manner as in Example 1, except that ETD was replaced with 1,4-methano-1,4,4a,9a-tetrahydrofluorene (hereinafter abbreviated as MTF) and 30 parts by weight of allyl glycidyl ether was replaced with 50 parts by weight. The synthesis results are shown in Table 1.

[Example 10] Epoxy-modified polymer (J) was obtained in the same manner as in Example 1, except that 3.83 mmol of 1-hexene was replaced with 5.75 mmol, ETD was replaced with MTF, and 30 parts by weight of allyl glycidyl ether was replaced with 50 parts by weight. The synthesis results are shown in Table 1.

[Example 11] A maleic anhydride-modified polymer (K) was obtained in the same manner as in Example 1, except that ETD was replaced with MTF and 30 parts by weight of allyl glycidyl ether was replaced with 50 parts by weight of maleic anhydride. The synthesis results are shown in Table 1.

Example 12 A maleic anhydride-modified polymer (L) was obtained in the same manner as in Example 1, except that 3.83 mmol of 1-hexene was replaced with 5.75 mmol, ETD was replaced with MTF, and 30 parts by weight of allyl glycidyl ether was replaced with 50 parts by weight of maleic anhydride. The synthesis results are shown in Table 1.

Comparative Example 1 An unmodified hydrogenated polymer was synthesized in the same manner as in Example 1 to give a polymer (M).

The synthesis results are shown in Table 2.

Comparative Example 2 Epoxy-modified polymer (N) was obtained in the same manner as in Example 1, except that the amount of allyl glycidyl ether was changed from 30 parts by weight to 3 parts by weight. The synthesis results are shown in Table 2.

Comparative Example 3 A maleic anhydride-modified polymer (O) was obtained in the same manner as in Example 1, except that 30 parts by weight of allyl glycidyl ether was replaced with 3 parts by weight of maleic anhydride. The synthesis results are shown in Table 2.

[Comparative Example 4] An unmodified hydrogenated product was synthesized in the same manner as in Example 5, and designated as polymer (P).

The synthesis results are shown in Table 2.

Comparative Example 5 Epoxy-modified polymer (Q) was obtained in the same manner as in Example 5, except that 100 parts by weight of allyl glycidyl ether was replaced with 15 parts by weight and 10 parts by weight of dicumyl peroxide was replaced with 1.0 part by weight. The synthesis results are shown in Table 2.

Comparative Example 6 A maleic anhydride-modified polymer (R) was obtained in the same manner as in Example 7, except that 100 parts by weight of maleic anhydride was replaced with 15 parts by weight and 10 parts by weight of dicumyl peroxide was replaced with 1.0 part by weight. The synthesis results are shown in Table 2.

[Comparative Example 7] An unmodified hydrogenated polymer was synthesized in the same manner as in Example 9, and designated as Polymer (S). The synthesis results are shown in Table 2.

Comparative Example 8 Epoxy-modified polymer (T) was obtained in the same manner as in Example 9, except that 50 parts by weight of allyl glycidyl ether was replaced with 10 parts by weight and 3.0 parts by weight of dicumyl peroxide was replaced with 1.0 part by weight. The synthesis results are shown in Table 2.

Comparative Example 9 A maleic anhydride-modified polymer (U) was obtained in the same manner as in Example 11, except that 50 parts by weight of maleic anhydride was replaced with 10 parts by weight and 3.0 parts by weight of dicumyl peroxide was replaced with 1.0 part by weight. The synthesis results are shown in Table 2.

Comparative Example 10 An unmodified hydrogenated polymer (V) was synthesized in the same manner as in Example 1, except that 3.83 mmol of 1-hexene was replaced with 2.30 mmol. The synthesis results are shown in Table 2.

[Examples 13 to 24] Each of the modified polymers obtained in Examples 1 to 12 was blended with various components according to the compositions shown in Table 3, and each was dissolved in toluene to give a solids concentration of 50 to 60 wt % to prepare a varnish. After leaving these solutions to stand for 30 minutes, the uniformity of the solutions was evaluated visually and rated according to the following criteria: Solution uniformity : ○: completely uniform, ×: phase separation occurred.

E-glass cloth measuring 10 cm in width, 10 cm in length, and approximately 0.5 mm in thickness was immersed in these solutions for 10 seconds, then slowly removed and left to stand for 1 minute. The solid content of the resulting resin-impregnated glass cloth was again dissolved in toluene and poured into a large amount of isopropyl acetate. The modified polymer was coagulated and recovered by filtration. Meanwhile, the filtered liquid was poured into a large amount of methanol, and the flame retardant was recovered in the same manner as above.

These were dried at 70°C x 1 Torr for 48 hours, and the weights of each were measured. Based on the difference between the weight ratio of the two components at this time and the weight ratio of the two components in the varnish state, the uniformity of impregnation was evaluated according to the following criteria: Uniformity of impregnation : ◎: Difference in weight ratio is less than 2%, ○: Difference in weight ratio is 2% or more but less than 5%, △: Difference in weight ratio is 5% or more but less than 10%, ×: Difference in weight ratio is 10% or more.

Furthermore, E-glass cloth was immersed in each of the solutions to impregnate the material, and then dried in an air oven to prepare a curable composite material (prepreg). The weight of the substrate in the prepreg was 40% of the prepreg weight. Multiple sheets of the prepreg were stacked as needed to achieve a molded thickness of 0.8 mm. 35 μm-thick copper foil was placed on both sides of the stack, and the resulting laminate was molded and cured using a hot press molding machine to obtain a resin laminate.

When the physical properties of the resin laminates thus obtained were measured, all of the resin laminates exhibited good dielectric constants, copper foil peel strength, and flame retardancy of V-0.

(Footnotes) Peroxide: a = 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3 Crosslinking aid: TAIC = triallyl isocyanurate Flame retardant: b = brominated bisphenol A epoxy resin (AER 8010; Br content = 5 wt %) manufactured by Asahi Chiba Corporation Curing agent: imidazole = 2-ethyl-4-methylimidazole Table 3 shows that in the examples of the present invention (Examples 13 to 24), even when the solid content was 50 to 60 wt %, the compounding ingredients such as the crosslinking agent, crosslinking aid, flame retardant, and curing agent were able to be uniformly dispersed, and the obtained molded articles were excellent in dielectric constant and in peel strength from the copper foil.

Comparative Examples 11-20 The same procedures as in Examples 13-24 were repeated, except that the modified or unmodified polymers obtained in Comparative Examples 1-10 were used instead of the modified polymers obtained in Examples 1-12. The results are shown in Table 4.

The results in Table 4 show that the unmodified polymer and the modified polymer with a small degree of modification have insufficient peel strength from the copper foil.

[Example 25] Epoxy-modified polymer (a) was obtained in the same manner as in Example 1, except that 1-hexene was replaced with 1.86 mmol instead of 3.83 mmol. The synthesis results are shown in Table 5.

Example 26 A maleic anhydride-modified polymer (b) was obtained in the same manner as in Example 25, except that 30 parts by weight of allyl glycidyl ether was replaced with 30 parts by weight of maleic anhydride.

The synthesis results are shown in Table 5.

[Example 27] Epoxy-modified polymer (c) was obtained in the same manner as in Example 25, except that ETD was replaced with DCP, 30 parts by weight of allyl glycidyl ether was replaced with 100 parts by weight, and 3.0 parts by weight of dicumyl peroxide was replaced with 10 parts by weight. The synthesis results are shown in Table 5.

Example 28 Maleic anhydride-modified polymer (d) was obtained in the same manner as in Example 27, except that allyl glycidyl ether was replaced with maleic anhydride. The synthesis results are shown in Table 5.

Example 29 Epoxy-modified polymer (e) was obtained in the same manner as in Example 25, except that ETD was replaced with MTF and 30 parts by weight of allyl glycidyl ether was replaced with 50 parts by weight. The synthesis results are shown in Table 5.

[Example 30] A maleic anhydride-modified polymer (f) was obtained in the same manner as in Example 29, except that allyl glycidyl ether was replaced with maleic anhydride. The synthesis results are shown in Table 5.

[Comparative Example 21] An unmodified hydrogenated polymer was synthesized in the same manner as in Example 25, and designated as polymer (g). The synthesis results are shown in Table 5.

Comparative Example 22 Epoxy-modified polymer (h) was obtained in the same manner as in Example 25, except that the 30 parts by weight of allyl glycidyl ether was changed to 3.0 parts by weight. The synthesis results are shown in Table 5.

[Comparative Example 23] Maleic anhydride-modified polymer (i) was obtained in the same manner as in Example 26, except that 30 parts by weight of maleic anhydride was replaced with 3.0 parts by weight. The synthesis results are shown in Table 5.

[Comparative Example 24] An unmodified hydrogenated polymer was synthesized in the same manner as in Example 27, and designated as Polymer (j). The synthesis results are shown in Table 5.

Comparative Example 25 Epoxy-modified polymer (k) was obtained in the same manner as in Example 27, except that 100 parts by weight of allyl glycidyl ether was replaced with 15 parts by weight. The synthesis results are shown in Table 5.

[Comparative Example 26] A maleic anhydride-modified polymer (l) was obtained in the same manner as in Example 28, except that 100 parts by weight of maleic anhydride was replaced with 15 parts by weight. The synthesis results are shown in Table 5.

[Comparative Example 27] An unmodified hydrogenated polymer was synthesized in the same manner as in Example 29, and designated as polymer (m). The synthesis results are shown in Table 5.

Comparative Example 28 Epoxy-modified polymer (n) was obtained in the same manner as in Example 29, except that 50 parts by weight of allyl glycidyl ether was replaced with 10 parts by weight. The synthesis results are shown in Table 5.

Comparative Example 29 A maleic anhydride-modified polymer (o) was obtained in the same manner as in Example 30, except that 50 parts by weight of maleic anhydride was replaced with 10 parts by weight. The synthesis results are shown in Table 5.

[Examples 31 to 36] 30 parts by weight of each of the modified polymers obtained in Examples 25 to 30 and 1.2 parts by weight of 4,4'-bisazidobenzal(4-methyl)cyclohexanone were dissolved in 100 parts by weight of xylene. Each solution became homogeneous without forming any precipitate.

Next, this homogeneous solution was spin-coated onto a silicon wafer with aluminum wiring formed on a 4000 angstrom-thick _SiO2 film, and pre-baked at 90°C for 60 seconds to form a 3.3 μm-thick coating on the aluminum wiring. Each sample thus obtained was cured at 250°C for 3 hours under nitrogen to form a 3 μm-thick overcoat film, and the dielectric constant, adhesion, solder heat resistance, and durability (heat resistance and moisture resistance) were evaluated. The results are shown in Table 6.

Comparative Examples 30-38 Examples 31-36 were repeated, except that the modified or unmodified polymers obtained in Comparative Examples 21-29 were used instead of the modified polymers obtained in Examples 25-30. The results are shown in Table 6.

The results in Table 6 show that by using the modified polymer of the present invention, an overcoat film (or interlayer insulating film) excellent in solder heat resistance, adhesion, durability, electrical properties, etc. can be obtained.

<Industrial Applications> The present invention provides a modified thermoplastic norbornene-based polymer that exhibits excellent electrical properties, such as dielectric constant and dielectric dissipation factor, and excellent adhesion to other materials, such as metals and silicon wafers. It also provides a method for producing the same, a crosslinkable polymer composition containing the modified thermoplastic norbornene-based polymer and a crosslinking agent, a molded product thereof, and sheets, prepregs, laminates, and other products made from the composition. The modified thermoplastic norbornene-based polymer and compositions containing the polymer of the present invention can be used in a wide range of applications, including circuit boards, interlayer insulating films, semiconductor devices, and electronic components for precision equipment such as electronic computers and communications devices.

─────────────────────────────────────────────────────── Continued from the front page (51) Int.Cl. ⁷ Identification symbol FI // C08G 61/08 (Note) This publication is based on the gazette published internationally by the International Bureau (WIPO). The effect of the international publication of the Japanese language patent application (Japanese language utility model registration application) related to this publication arises pursuant to Article 184-10, Paragraph 1 of the Patent Act (Article 48-13, Paragraph 2 of the Utility Model Act), and is unrelated to this publication.

Claims (15)

[Claims] 1. A modified thermoplastic norbornene polymer, obtained by graft-modifying a thermoplastic norbornene polymer selected from ring-opening polymers of norbornene monomers and their hydrogenated products with at least one unsaturated compound selected from the group consisting of unsaturated epoxy compounds and unsaturated carboxylic acid compounds, having a graft modification rate of at least 10 mol% and a number-average molecular weight (Mn) of 500 to 500,000. 2. The thermoplastic norbornene-based polymer is represented by the formula (A): (wherein ^R1 to ^R8 each independently represent a hydrogen atom, a hydrocarbon group, a halogen atom, an alkoxy group, an ester group, a cyano group, an amide group, an imide group, a silyl group, or a hydrocarbon group substituted with a polar group (i.e., a halogen atom, an alkoxy group, an ester group, a cyano group, an amide group, an imide group, or a silyl group). However, two or more of ^R5 to ^R8 may bond together to form a monocycle or a polycycle, and this monocycle or polycycle may have a carbon-carbon double bond or form an aromatic ring. ^R5 and ^R6 , or ^R7 and ^R8 may together form an alkylidene group. ... represents a single bond or a double bond.) 3. The modified thermoplastic norbornene ring-opening polymer according to claim 1 or 2, wherein the graft modification rate is 10 to 100 mol %. 4. The modified thermoplastic norbornene ring-opening polymer according to claim 1 or 2, wherein the graft modification rate is 15 to 50 mol %. 5. The modified thermoplastic norbornene ring-opening polymer according to any one of claims 1 to 4, having a number average molecular weight (Mn) in the range of 500 to 20,000. 6. The modified thermoplastic norbornene ring-opening polymer according to any one of claims 1 to 4, having a number average molecular weight (Mn) in the range of more than 20,000 and not more than 500,000. 7. A method for producing a modified thermoplastic norbornene-based polymer having a number-average molecular weight (Mn) of 500 to 500,000 and a graft modification rate of at least 10 mol %, the method comprising reacting a thermoplastic norbornene-based polymer having a number-average molecular weight (Mn) of 500 to 500,000 selected from ring-opening polymers of norbornene-based monomers and hydrogenated products thereof with at least one unsaturated compound selected from the group consisting of unsaturated epoxy compounds and unsaturated carboxylic acid compounds in the presence of an organic peroxide. 8. A crosslinkable polymer composition comprising a modified thermoplastic norbornene-based polymer selected from ring-opening polymers of norbornene-based monomers and their hydrogenated products, graft-modified with at least one unsaturated compound selected from the group consisting of unsaturated epoxy compounds and unsaturated carboxylic acid compounds, resulting in a graft-modification rate of at least 10 mol % and a number-average molecular weight (Mn) of 500 to 500,000, and a crosslinking agent. 9. The crosslinkable polymer composition according to claim 8, wherein the crosslinking agent is selected from the group consisting of organic peroxides, crosslinking agents activated by heat, and crosslinking agents activated by light. 10. The crosslinkable polymer composition according to claim 8 or 9, containing 0.001 to 30 parts by weight of a crosslinking agent per 100 parts by weight of the modified thermoplastic norbornene-based polymer. 11. The crosslinkable polymer composition according to any one of claims 8 to 10, further comprising a crosslinking aid. 12. The crosslinkable polymer composition according to any one of claims 8 to 11, further comprising a flame retardant. 13. A molded article obtained by molding the crosslinkable polymer composition according to any one of claims 8 to 12. 14. A laminate having a structure in which a layer made of the crosslinkable polymer composition according to any one of claims 8 to 12 and a metal layer are laminated together. 15. A prepreg obtained by impregnating a reinforcement substrate with the crosslinkable polymer composition according to any one of claims 8 to 12.