Polymerizable composition and resin-impregnated superconducting coil

Abstract

Provided is a polymerizable composition that is for a resin-impregnated superconducting coil and that has excellent impregnation ability and can be used for manufacturing a resin-impregnated superconducting coil having excellent durability in a high-dose environment (in a high-dose environment in which the radiation dose per 100,000 hours is at least 1 MGy). Provided is a polymerizable composition for a resin-impregnated superconducting coil used in a high-dose environment in which the radiation dose per 100,000 hours is at least 1 MGy, the polymerizable composition comprising a norbornene-based monomer, rare-earth element-containing particles, and a metathesis polymerization catalyst.

Description

Polymerizable composition and resin-impregnated superconducting coil

[0001] The present invention relates to a polymerizable composition for a resin-impregnated superconducting coil used in a high-dose environment where the radiation exposure dose per 100,000 hours is 1 MGy or more, and a resin-impregnated superconducting coil obtained using such a polymerizable composition.

[0002] Superconducting coils for generating magnetic fields in particle accelerators are usually used in high-dose environments where the radiation exposure per 100,000 hours or over the entire operation period is 1 MGy or more. Therefore, when a resin-impregnated superconducting coil obtained by impregnating a superconducting coil with resin is used in such a high-dose environment, the resin in the resin-impregnated superconducting coil is required to have durability in the high-dose environment.

[0003] On the other hand, it is known that resins deteriorate due to decomposition reactions and the like caused by radiation exposure, and therefore, measures to suppress the deterioration of resins due to radiation are being studied.

[0004] For example, Non-Patent Document 1 discloses the results of investigating the fluctuations of additives, polymers and additive decomposition products, monomers, etc., as well as changes in tensile strength, color tone, odor, etc., due to gamma ray irradiation using films or sheets made of polyethylene, polypropylene, and polystyrene to which a specific antioxidant has been added. Specifically, when a polymer to which no antioxidant has been added was irradiated with gamma rays at a maximum of 50 kGy, volatile substances thought to be polymer decomposition products were detected, and the tensile strength, color tone, odor, etc. were deteriorated, whereas the production of polymer decomposition products such as acetic acid, propionic acid, 2-butanone, and 2,4-pentanedione was suppressed by the addition of an antioxidant, and the decrease in tensile strength of polypropylene was also improved by the addition of a specific antioxidant.

[0005] Furthermore, Non-Patent Document 2 discloses the results of irradiating polymer blends obtained by mixing polypropylene (PP) and polyethylene (LDPE) samples at different weight ratios with radiation of up to 100 kGy, and concludes that the polymer blends may have improved physical and thermal properties of the polymers that make up the polymer blend, and may have properties that make them usable in applications involving radiation.

[0006] However, Non-Patent Document 1 only discloses the results of irradiation with gamma rays up to 50 kGy, and Non-Patent Document 2 only discloses the results of irradiation with gamma rays up to 100 kGy, and the durability under a high-dose environment where the material is exposed to radiation irradiation on the order of MGy is not evaluated.

[0007] Yoko Kawamura and two others, "Effect of gamma irradiation on antioxidant-containing polyethylene, polypropylene, and polystyrene," Food Irradiation, Japan Food Irradiation Research Council, September 30, 2003, Vol. 38, No. 1, 2 (2003), pp. 11-22; Mehtap Sirin and two others, "Effect of gamma irradiation on the thermal and mechanical behavior of polypropylene and polyethylene blends," Radiation Physics and Chemistry, 2022, 194 (2022) 110034, pp. 1-11

[0008] The present invention has been made in view of the above circumstances, and has an object to provide a polymerizable composition for a resin-impregnated superconducting coil, which can be used to produce a resin-impregnated superconducting coil that has excellent impregnation properties and durability in a high-dose environment (a high-dose environment in which the radiation exposure dose per 100,000 hours is 1 MGy or more).

[0009] As a result of investigations conducted by the present inventors to achieve the above-mentioned object, they found that the above-mentioned object can be achieved by a polymerizable composition comprising a norbornene-based monomer and a metathesis polymerization catalyst, and rare earth element-containing particles, and thus completed the present invention.

[0010] That is, according to the present invention, the following polymerizable composition and resin-impregnated superconducting coil are provided. [1] A polymerizable composition for a resin-impregnated superconducting coil used in a high-dose environment where the radiation exposure per 100,000 hours is 1 MGy or more, the polymerizable composition comprising a norbornene-based monomer, rare-earth element-containing particles, and a metathesis polymerization catalyst. [2] The polymerizable composition according to [1], wherein the rare-earth element-containing particles contain at least one rare-earth element selected from cerium, praseodymium, gadolinium, dysprosium, holmium, and erbium. [3] The polymerizable composition according to [1] or [2], wherein the content of the rare-earth element-containing particles is 4 to 90 mass %. [4] The polymerizable composition according to any one of [1] to [3], wherein the norbornene-based monomer contains 50 mass % or more of dicyclopentadiene. [5] The polymerizable composition according to any one of [1] to [4], wherein the norbornene-based monomer contains a tricyclic ring and a pentacyclic ring. [6] The polymerizable composition according to any one of claims [1] to [5], further comprising a silane coupling agent. [7] The polymerizable composition according to any one of [1] to [6], comprising two or more pre-mixed liquids that do not undergo polymerization reaction alone, and which can form the polymerizable composition by combining the pre-mixed liquids. [8] The polymerizable composition according to any one of [1] to [7], wherein the resin-impregnated superconducting coil is a superconducting coil for generating a magnetic field for a particle accelerator. [9] A resin-impregnated superconducting coil used in a high-dose environment where the radiation exposure per 100,000 hours is 1 MGy or more, the resin-impregnated superconducting coil being impregnated with a norbornene-based resin obtained by bulk polymerization of the polymerizable composition according to any one of [1] to [8].

[10] The resin-impregnated superconducting coil according to [9], wherein the norbornene-based resin has a specific heat capacity of 3.0 J / K / kg or more at a temperature of 4 K.

[0011] According to the present invention, it is possible to provide a polymerizable composition for a resin-impregnated superconducting coil, which can be used to produce a resin-impregnated superconducting coil that has excellent impregnation properties and durability in a high-dose environment (a high-dose environment in which the radiation exposure dose per 100,000 hours is 1 MGy or more).

[0012] FIG. 1A is a schematic perspective view of a resin-impregnated superconducting coil according to one embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view of the resin-impregnated superconducting coil according to one embodiment of the present invention.

[0013] <Polymerizable Composition> The polymerizable composition of the present invention is a polymerizable composition for a resin-impregnated superconducting coil used in a high-dose environment where the radiation exposure dose per 100,000 hours is 1 MGy or more, and contains a norbornene-based monomer, rare-earth element-containing particles, and a metathesis polymerization catalyst.

[0014] Superconducting coils for generating magnetic fields in particle accelerators are typically used in high-dose environments where the radiation exposure per 100,000 hours is 1 MGy or more. Specifically, the radiation exposure per 100,000 hours for superconducting coils for generating magnetic fields in particle accelerators is typically thought to be about 2 to 5 MGy. For example, when a superconducting coil for generating magnetic fields in a particle accelerator operates for 100,000 hours, the average radiation exposure per unit time for the superconducting coil is typically 10 Gy / h or more, but is estimated to be about 20 to 50 Gy / h in high-dose environments.

[0015] In contrast, the polymerizable composition of the present invention can provide a norbornene-based resin that is excellent in durability in a high-dose environment where the radiation exposure dose per 100,000 hours falls within the above-mentioned range. Therefore, by using the polymerizable composition of the present invention, it is possible to produce a resin-impregnated superconducting coil that can be used stably for a long period of time even in such a high-dose environment.

[0016] The resin-impregnated superconducting coil obtained using the polymerizable composition of the present invention can be suitably used in an environment where the radiation exposure dose per 100,000 hours is 1 MGy or more. The lower limit of the radiation exposure dose per 100,000 hours for the resin-impregnated superconducting coil obtained using the polymerizable composition of the present invention is more preferably 2 MGy or more, and even more preferably 3 MGy or more. The upper limit of the radiation exposure dose per 100,000 hours is preferably 30 MGy or less, more preferably 25 MGy or less, and even more preferably 20 MGy or less. The upper limit of the radiation exposure dose per 100,000 hours may be 15 MGy or less, 10 MGy or less, 8 MGy or less, or 6 MGy or less.

[0017] Furthermore, a resin-impregnated superconducting coil obtained using the polymerizable composition of the present invention can be suitably used in an environment where the total cumulative radiation exposure dose is 1 MGy or more. The lower limit of the total cumulative radiation exposure dose for a resin-impregnated superconducting coil obtained using the polymerizable composition of the present invention is more preferably 2 MGy or more, and even more preferably 3 MGy or more. The upper limit of the total cumulative radiation exposure dose is preferably 30 MGy or less, more preferably 25 MGy or less, and even more preferably 20 MGy or less. The upper limit of the total cumulative radiation exposure dose may be 15 MGy or less, 10 MGy or less, 8 MGy or less, or 6 MGy or less. For example, the radiation exposure dose per 100,000 hours may be within the above range.

[0018] Furthermore, since the polymerizable composition of the present invention contains a norbornene-based monomer, it has low viscosity, and therefore, when applied to a superconducting coil, the polymerizable composition of the present invention exhibits sufficient impregnation properties for the superconducting coil, and therefore the polymerizable composition of the present invention can be suitably used for producing a resin-impregnated superconducting coil.

[0019] In addition, the norbornene-based resin obtained using the polymerizable composition of the present invention has excellent mechanical properties even at extremely low temperatures, while having a relatively low adhesive strength with the superconducting wire that constitutes the superconducting coil. Therefore, even if the norbornene-based resin undergoes thermal contraction during cooling, the destruction of the superconducting coil due to tensile stress caused by the thermal contraction can be suppressed, thereby effectively suppressing the occurrence of quenching, which is the cause of the destruction of the superconducting coil.

[0020] The norbornene-based monomer may be any compound having a norbornene ring structure, and is not particularly limited. Examples include bicyclic compounds such as norbornene and norbornadiene; tricyclic compounds such as dicyclopentadiene; tetracyclic compounds such as tetracyclododecene; pentacyclic compounds such as tricyclopentadiene; heptacyclic compounds such as tetracyclopentadiene; and derivatives thereof having an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkylidene group having 1 to 10 carbon atoms, an epoxy group, or a (meth)acrylic group. The norbornene-based monomer may be used alone or in combination of two or more. From the viewpoint of further enhancing the effects of the present invention, the tricyclic compounds are preferred as the norbornene-based monomer, and dicyclopentadiene is particularly preferred. The norbornene-based monomer used preferably contains 50% by mass or more of the tricyclic compounds, particularly dicyclopentadiene. It is also preferable to use the tricyclic compound and the pentacyclic compound in combination as the norbornene-based monomer. In this case, the mass ratio of "tricyclic compound:pentacyclic compound" is preferably 60:40 to 97:3, and more preferably 80:20 to 95:5.

[0021] The content of the norbornene-based monomer in the polymerizable composition of the present invention is not particularly limited, but is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on 100% by mass of all polymerizable monomers contained in the polymerizable composition. By setting the content of the norbornene-based monomer within the above range, the norbornene-based resin obtained using the polymerizable composition of the present invention can be made to have even better durability in high-dose environments. Furthermore, by setting the content of the norbornene-based monomer within the above range, the mechanical properties at cryogenic temperatures can be further improved while the adhesive strength to the superconducting wire constituting the superconducting coil is sufficiently reduced.

[0022] In the present invention, a monocyclic cycloolefin may further be used as a polymerizable monomer contained in the polymerizable composition.

[0023] The monocyclic cycloolefin is not particularly limited, but examples thereof include cyclobutene, cyclopentene, cyclohexene, cyclooctene, cyclododecene, cyclopentadiene, 1,4-cyclohexadiene, 1,5-cyclooctadiene, and derivatives thereof having an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkylidene group having 1 to 10 carbon atoms, an epoxy group, or a (meth)acrylic group. The monocyclic cycloolefin may be used alone or in combination of two or more types.

[0024] The polymerizable composition of the present invention may contain, in addition to the norbornene-based monomer and the monocyclic cycloolefin, other polymerizable monomers polymerizable with them, such as other cycloolefin monomers.

[0025] The content of polymerizable monomers other than norbornene-based monomers in the polymerizable composition of the present invention is not particularly limited, but is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, relative to 100% by mass of the total polymerizable monomers contained in the polymerizable composition, and may be 0% by mass.

[0026] The total content of polymerizable monomers including norbornene-based monomers in the polymerizable composition of the present invention is preferably 10 to 95 mass%, more preferably 12 to 90 mass%, and even more preferably 15 to 50 mass%, relative to 100 mass% of the total polymerizable composition.

[0027] The polymerizable composition of the present invention contains rare earth element-containing particles, which allows the polymerizable composition of the present invention to have excellent durability in a high-dose environment (a high-dose environment in which the radiation exposure dose per 100,000 hours is 1 MGy or more).

[0028] The rare earth element-containing particles used in the present invention are not particularly limited as long as they contain a rare earth element, but are preferably those containing at least one rare earth element selected from cerium, praseodymium, gadolinium, dysprosium, holmium and erbium, and more preferably those containing at least one rare earth element selected from gadolinium and holmium. Furthermore, as rare earth element-containing particles, from the viewpoint of high specific heat and excellent heat storage property, CeCu ６ , CeAl ２ , HoCu ２ , Er ３ Ni, PrB ６ , PrCu ２ , DyCu ２ , GdCu ２ , Gd ２ O ３ , and Gd ２ O ２ Preferably, the compound contains at least one rare earth compound selected from the group consisting of HoCu and S. ２ , Gd ２ O ３ , and Gd ２ O ２ More preferably, the compound contains at least one rare earth compound selected from S, and Gd ２ O ３ and Gd ２ O ２ More preferably, the compound contains at least one rare earth compound selected from S, and Gd ２ O ３ Particularly preferred are those containing:

[0029] Furthermore, the rare earth element-containing particles used in the present invention may further include silver oxide (Ag ２ O) and copper oxide (Cu ２ The material may further contain metal oxides such as bismuth (Bi) and lead (Pb).

[0030] The particle size of the rare earth element-containing particles used in the present invention is not particularly limited, but the mode diameter on a number basis is preferably 0.05 μm or more and less than 1.5 μm, more preferably 0.07 to 1.3 μm, even more preferably 0.1 to 1.2 μm, and particularly preferably 0.7 to 1.1 μm. When the mode diameter on a number basis of the rare earth element-containing particles is within the above range, the rare earth element-containing particles have excellent heat storage properties and also excellent heat dissipation properties, so that a resin-impregnated superconducting coil produced using the polymerizable composition of the present invention can be cooled in a shorter time than conventional coils.

[0031] The number-based mode diameter is the particle diameter with the highest probability of existence on a number basis, and the particle diameter showing the maximum value on a particle size distribution curve obtained by plotting the frequency of existence of individual particle diameters against the logarithm of particle diameter on a number basis can be taken as the number-based mode diameter. The number-based mode diameter of rare earth element-containing particles can be calculated, for example, by determining the particle size distribution converted into a number basis from the particle size distribution measured by a light scattering method (laser diffraction / scattering method).

[0032] The shape of the rare earth element-containing particles is not particularly limited, but examples thereof include spherical, bale-shaped, spheroidal, cylindrical, fibrous, and irregular shapes, and the particles may be a mixture of particles of a plurality of these shapes. For example, spherical rare earth element-containing particles and cylindrical rare earth element-containing particles may be combined. Furthermore, the rare earth element-containing particles may be a mixture of two or more types of particles having different compositions.

[0033] The rare earth element-containing particles may also be particles of a rare earth element compound containing a rare earth element, on the surface of which a coating layer is formed of a metal having high electrical and thermal conductivity, such as silver, gold, nickel, or copper.

[0034] The rare earth element-containing particles used in the present invention may have their surfaces hydrophobized. Using hydrophobized rare earth element-containing particles can prevent aggregation and sedimentation of the particles in the polymerizable composition and ensure uniform dispersion of the particles in the norbornene-based resin obtained by bulk polymerization of the polymerizable composition. Examples of treating agents used for hydrophobization include silane coupling agents, titanate coupling agents, aluminum coupling agents, fatty acids such as stearic acid, oils and fats, surfactants, and waxes. The treating agent can also be simply blended with the rare earth element-containing particles in the polymerizable composition.

[0035] As the treating agent, a silane coupling agent having at least one hydrocarbon group with a norbornene structure is preferably used because, even when rare earth element-containing particles are incorporated into the polymerizable composition, the viscosity is low and thixotropy (viscosity at rest) is unlikely to increase. While such silane coupling agents can also function as monomers, they are treated as silane coupling agents in the present invention. Specific examples of such silane coupling agents include bicycloheptenyltrimethoxysilane, bicycloheptenyltriethoxysilane, bicycloheptenylethyltrimethoxysilane, and bicycloheptenylethyltriethoxysilane. Other silane coupling agents, such as vinyltrimethoxysilane, that do not have a norbornene structure can also be used as the treating agent. The treating agents can be used alone or in combination of two or more. The content of the treating agent in the polymerizable composition of the present invention is preferably 0.1 to 5% by mass, more preferably 0.3 to 2% by mass, and even more preferably 0.5 to 1% by mass.

[0036] The content of the rare earth element-containing particles in the polymerizable composition of the present invention is preferably 4 to 90 mass %, more preferably 10 to 88 mass %, even more preferably 20 to 87 mass %, still more preferably 70 to 86 mass %, and particularly preferably 75 to 85 mass %, based on 100 mass % of the total polymerizable composition. By setting the content of the rare earth element-containing particles within this range, it is possible to ensure that the fluidity of the uncured polymerizable composition is sufficiently high while also ensuring sufficient protection performance for the superconducting wire.

[0037] The metathesis polymerization catalyst used in the present invention is not particularly limited as long as it can ring-opening polymerize norbornene-based monomers, and known metathesis polymerization catalysts can be used.

[0038] The metathesis polymerization catalyst used in the present invention is a complex formed by bonding a plurality of ions, atoms, polyatomic ions, and / or compounds to a transition metal atom as a central atom. The transition metal atom is an atom of Groups 5, 6, and 8 (long-form periodic table, the same applies hereinafter). The atom of each group is not particularly limited, but examples of Group 5 atoms include tantalum, examples of Group 6 atoms include molybdenum and tungsten, and examples of Group 8 atoms include ruthenium and osmium. Among these transition metal atoms, ruthenium and osmium of Group 8 are preferred. That is, the metathesis polymerization catalyst used in the present invention is preferably a complex having ruthenium or osmium as a central atom, and more preferably a complex having ruthenium as a central atom. As a complex having ruthenium as a central atom, a ruthenium-carbene complex in which a carbene compound is coordinated to ruthenium is preferred. Here, "carbene compound" is a general term for compounds having a methylene free radical, and refers to a compound having an uncharged divalent carbon atom (carbene carbon) represented by (>C:). Ruthenium carbene complexes have excellent catalytic activity during bulk ring-opening polymerization, so the resulting polymer has little odor due to unreacted monomers, and high-quality polymers can be obtained with good productivity. In addition, they are relatively stable against oxygen and moisture in the air and are not easily deactivated, so they can be used in the atmosphere. The metathesis polymerization catalyst may be used alone or in combination of multiple types.

[0039] Examples of the ruthenium carbene complex include those represented by the following general formula (1) or (2).

[0040] In the above general formulas (1) and (2), R １ and R ２ are each independently a hydrogen atom; a halogen atom; or an organic group having 1 to 20 carbon atoms which may contain a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or a silicon atom; and these groups may have a substituent, and may be bonded to each other to form a ring. １ and R ２ Examples of groups bonded to each other to form a ring include an indenylidene group which may have a substituent, such as a phenylindenylidene group.

[0041] Specific examples of the organic group having 1 to 20 carbon atoms which may contain a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom or a silicon atom include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkenyloxy group having 2 to 20 carbon atoms, an alkynyloxy group having 2 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aryloxy group having 1 to 8 carbon atoms, an alkyl group having 1 to 20 carbon atoms, an alkyl group having 2 to 20 carbon atoms, an alkynyloxy group having 2 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an alkyl group having 1 to 8 ... alkyl group having 2 to 20 carbon atoms, an alkyl group having 2 to 20 carbon atoms, an alkyl group having 2 to 20 carbon atoms, an alkyl group having 2 to 20 carbon atoms, an alkyl group having 2 to 20 carbon atoms, an alkyl group having 2 to Examples of the organic group include alkylthio groups, carbonyloxy groups, alkoxycarbonyl groups having 1 to 20 carbon atoms, alkylsulfonyl groups having 1 to 20 carbon atoms, alkylsulfinyl groups having 1 to 20 carbon atoms, alkylsulfonic acid groups having 1 to 20 carbon atoms, arylsulfonic acid groups having 6 to 20 carbon atoms, phosphonic acid groups, arylphosphonic acid groups having 6 to 20 carbon atoms, alkylammonium groups having 1 to 20 carbon atoms, and arylammonium groups having 6 to 20 carbon atoms. These organic groups having 1 to 20 carbon atoms, which may contain a halogen atom, oxygen atom, nitrogen atom, sulfur atom, phosphorus atom, or silicon atom, may have a substituent. Examples of the substituent include alkyl groups having 1 to 10 carbon atoms, alkoxy groups having 1 to 10 carbon atoms, and aryl groups having 6 to 10 carbon atoms.

[0042] X １ and X ２each independently represents an anionic ligand. The anionic ligand is a ligand that has a negative charge when separated from the central metal atom, and examples thereof include a halogen atom, a diketonate group, a substituted cyclopentadienyl group, an alkoxyl group, an aryloxy group, and a carboxyl group.

[0043] L １ and L ２ represents a heteroatom-containing carbene compound or a neutral electron donor compound other than a heteroatom-containing carbene compound. Heteroatom-containing carbene compounds and neutral electron donor compounds other than a heteroatom-containing carbene compound are compounds that have a neutral charge when separated from a central metal. From the viewpoint of improving catalytic activity, heteroatom-containing carbene compounds are preferred. The heteroatom refers to an atom of Groups 15 and 16 of the periodic table, and specific examples include a nitrogen atom, an oxygen atom, a phosphorus atom, a sulfur atom, an arsenic atom, and a selenium atom. Among these, from the viewpoint of obtaining a stable carbene compound, a nitrogen atom, an oxygen atom, a phosphorus atom, and a sulfur atom are preferred, and a nitrogen atom is more preferred.

[0044] The heteroatom-containing carbene compound is preferably a compound represented by the following general formula (3) or (4), and from the viewpoint of improving catalytic activity, a compound represented by the following general formula (3) is more preferred.

[0045] In the above general formulas (3) and (4), R ３ , R ４ , R ５ and R ６ each independently represents a hydrogen atom; a halogen atom; or an organic group having 1 to 20 carbon atoms which may contain a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or a silicon atom. Specific examples of the organic group having 1 to 20 carbon atoms which may contain a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or a silicon atom are the same as those in the general formulas (1) and (2) above. ３ , R ４ , R ５ and R ６ may be bonded to each other in any combination to form a ring.

[0046] In addition, since the effect of the present invention becomes more remarkable, R ５ and R ６ is preferably a hydrogen atom. ３ and R ４ is preferably an aryl group which may have a substituent, more preferably a phenyl group having an alkyl group of 1 to 10 carbon atoms as a substituent, and even more preferably a mesityl group.

[0047] Examples of the neutral electron donor compound include oxygen atoms, water, carbonyls, ethers, nitriles, esters, phosphines, phosphinites, phosphites, sulfoxides, thioethers, amides, imines, aromatic compounds, cyclic diolefins, olefins, isocyanides, and thiocyanates.

[0048] In the above general formulas (1) and (2), R １ , R ２ , X １ , X ２ , L １ and L ２ may be linked together alone and / or in any combination to form multidentate chelating ligands.

[0049] Furthermore, as the ruthenium carbene complex used in the present invention, among the compounds represented by the above general formula (1) or (2), the compound represented by the above general formula (1) is preferred in that the effects of the present invention are more pronounced, and among these, the compound represented by the following general formula (5) or general formula (6) is more preferred.

[0050] General formula (5) is shown below.

[0051] In the general formula (5), Z is an oxygen atom, a sulfur atom, a selenium atom, or NR １２ , P.R. １２ or AsR １２ and R １２represents a hydrogen atom; a halogen atom; or an organic group having 1 to 20 carbon atoms which may contain a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or a silicon atom; however, an oxygen atom is preferred as Z because the effects of the present invention will be more pronounced.

[0052] In addition, R １ , R ２ , X １ and L １ are the same as those in the above general formulas (1) and (2), and may be bonded to each other alone or in any combination to form a multidentate chelating ligand, but X １ and L １ does not form a multidentate chelating ligand, and R １ and R ２ are preferably bonded to each other to form a ring, are more preferably an indenylidene group which may have a substituent, and are even more preferably a phenylindenylidene group. Specific examples of the organic group having 1 to 20 carbon atoms which may contain a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or a silicon atom are the same as those in the general formulae (1) and (2) above.

[0053] In the above general formula (5), R ７ and R ８ are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or a heteroaryl group having 6 to 20 carbon atoms, and these groups may have a substituent or may be bonded to each other to form a ring. Examples of the substituent include an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms, and when a ring is formed, the ring may be any of an aromatic ring, an alicyclic ring, and a heterocyclic ring, but it is preferable to form an aromatic ring, more preferably an aromatic ring having 6 to 20 carbon atoms, and even more preferably an aromatic ring having 6 to 10 carbon atoms.

[0054] In the above general formula (5), R ９ , R １０ and R １１are each independently a hydrogen atom, a halogen atom, or an organic group having 1 to 20 carbon atoms which may contain a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or a silicon atom, and these groups may have a substituent or may be bonded to each other to form a ring. Specific examples of the organic group having 1 to 20 carbon atoms which may contain a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or a silicon atom are the same as those in the above general formulas (1) and (2).

[0055] R ９ , R １０ and R １１ is preferably a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

[0056] Specific examples of the compound represented by the general formula (5) and the method for producing the same are described in, for example, WO 03 / 062253 (JP 2005-515260 A).

[0057] General formula (6) is shown below.

[0058] In the above general formula (6), m is 0 or 1. m is preferably 1, in which case Q is an oxygen atom, a nitrogen atom, a sulfur atom, a methylene group, an ethylene group or a carbonyl group, and preferably a methylene group.

[0059] In the above general formula (6), is a single bond or a double bond, preferably a single bond.

[0060] R １ , X １ , X ２ and L １ are the same as those in the above general formulas (1) and (2), and may be bonded to each other alone or in any combination to form a multidentate chelating ligand, but X １ , X ２ and L １ does not form a multidentate chelating ligand, and R １ is preferably a hydrogen atom.

[0061] R１３ ~R ２１ represents a hydrogen atom, a halogen atom, or an organic group having 1 to 20 carbon atoms which may contain a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or a silicon atom; these groups may have a substituent and may be bonded to each other to form a ring. Specific examples of the organic group having 1 to 20 carbon atoms which may contain a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or a silicon atom are the same as those in the above general formulas (1) and (2).

[0062] R １３ is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and R １４ ~R １７ is preferably a hydrogen atom, and R １８ ~R ２１ is preferably a hydrogen atom or a halogen atom.

[0063] Specific examples of the compound represented by the general formula (6) and its production method include those described in International Publication No. 11 / 079799 (JP 2013-516392).

[0064] The content of the metathesis polymerization catalyst is preferably 0.005 mmol or more, more preferably 0.01 to 50 mmol, and even more preferably 0.015 to 20 mmol, per mole of the total amount of polymerizable monomers used in the reaction.

[0065] Furthermore, the polymerizable composition of the present invention may contain a radical generator, a diisocyanate compound, a polyfunctional (meth)acrylate compound, and other optional components, if desired.

[0066] The radical generator generates radicals upon heating, thereby inducing a crosslinking reaction in the norbornene-based resin formed by bulk polymerization. The sites at which the radical generator induces the crosslinking reaction are mainly carbon-carbon double bonds contained in the norbornene-based resin, but crosslinking may also occur in saturated bond moieties. Examples of radical generators include organic peroxides, diazo compounds, and non-polar radical generators.

[0067] The amount of the radical generator in the polymerizable composition of the present invention is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the total amount of polymerizable monomers used in the reaction.

[0068] Examples of diisocyanate compounds include 4,4'-methylenediphenyl diisocyanate (MDI), toluene-2,4-diisocyanate, 4-methoxy-1,3-phenylene diisocyanate, 4-isopropyl-1,3-phenylene diisocyanate, 4-chloro-1,3-phenylene diisocyanate, 4-butoxy-1,3-phenylene diisocyanate, 2,4-diisocyanate diphenyl ether, 1,4-phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate (XDI), 1,5-naphthalene diisocyanate, benzidine diisocyanate, o-nitrobenzidine diisocyanate, and 4,4'-diisocyanate dibenzidine. Examples of suitable diisocyanate compounds include aromatic diisocyanate compounds such as benzyl; aliphatic diisocyanate compounds such as methylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, and 1,10-decamethylene diisocyanate; alicyclic diisocyanate compounds such as 4-cyclohexylene diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,5-tetrahydronaphthalene diisocyanate, isophorone diisocyanate, hydrogenated MDI, and hydrogenated XDI, as well as polyurethane prepolymers obtained by reacting these diisocyanate compounds with low-molecular-weight polyols or polyamines so as to form isocyanate groups at the terminals. Furthermore, conventionally known compounds having a polyfunctional isocyanate group, such as isocyanurates, biurets, adducts, or polymers of these compounds, can be used without particular limitation. Examples of such compounds include a dimer of 2,4-toluylene diisocyanate, triphenylmethane triisocyanate, tris-(p-isocyanatophenyl)thiophosphite, polyfunctional aromatic isocyanate compounds, polyfunctional aromatic aliphatic isocyanate compounds, polyfunctional aliphatic isocyanate compounds, fatty acid-modified polyfunctional aliphatic isocyanate compounds, polyfunctional blocked isocyanate compounds such as blocked polyfunctional aliphatic isocyanate compounds, and polyisocyanate prepolymers.Among these, polyfunctional unblocked isocyanate compounds, such as aromatic diisocyanate compounds, aliphatic diisocyanate compounds, and alicyclic diisocyanate compounds, are preferably used because of their easy availability and ease of handling. These compounds can be used alone or in combination of two or more.

[0069] A polyfunctional blocked isocyanate compound is one in which at least two isocyanate groups in the molecule are reacted with an active hydrogen-containing compound to render the compound inactive at room temperature. The isocyanate compound generally has a structure in which the isocyanate groups are masked with a blocking agent such as an alcohol, a phenol, ε-caprolactam, an oxime, or an active methylene compound. Polyfunctional blocked isocyanate compounds generally do not react at room temperature and therefore have excellent storage stability. However, heating at temperatures typically between 140 and 200°C regenerates the isocyanate groups, allowing the compound to exhibit excellent reactivity.

[0070] The diisocyanate compounds may be used alone or in combination of two or more. The amount of the diisocyanate compound in the polymerizable composition of the present invention is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 10 parts by mass, per 100 parts by mass of the total amount of the polymerizable monomers used in the reaction.

[0071]

[0033] Furthermore, from the viewpoint of further improving the mechanical properties at cryogenic temperatures of the norbornene-based resin obtained using the polymerizable composition of the present invention, a polyfunctional (meth)acrylate compound may be used. By using the polyfunctional (meth)acrylate compound together with a diisocyanate compound, the active hydrogen-reactive group of the diisocyanate compound forms a chemical bond with the hydroxyl group present in the polyfunctional (meth)acrylate compound, thereby further improving the mechanical properties at cryogenic temperatures of the norbornene-based resin. Preferred examples of the polyfunctional (meth)acrylate compound include ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and neopentyl glycol dimethacrylate.

[0072] The polyfunctional (meth)acrylate compounds may be used alone or in combination of two or more. The amount of the polyfunctional (meth)acrylate compound in the polymerizable composition of the present invention is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 10 parts by mass, per 100 parts by mass of the total amount of polymerizable monomers used in the reaction.

[0073] Other optional components include activators, activity regulators, elastomers, antioxidants (antiaging agents), dispersants, and the like.

[0074] The activator is a compound that acts as a cocatalyst for the metathesis polymerization catalyst described above and improves the polymerization activity of the catalyst. Examples of the activator include alkylaluminum halides such as ethylaluminum dichloride and diethylaluminum chloride; alkoxyalkylaluminum halides in which a portion of the alkyl groups in these alkylaluminum halides is substituted with an alkoxy group; and organotin compounds. The amount of the activator used is not particularly limited, but is preferably 0.1 to 100 mol, and more preferably 1 to 10 mol, per mol of the total metathesis polymerization catalysts used in the polymerizable composition.

[0075] The activity regulator is used to prevent polymerization from starting during the injection process when a polymerizable composition is prepared by mixing two or more reaction stock solutions as described below and then injected into a mold to initiate polymerization.

[0076] When a compound of a transition metal of Group 5 or 6 of the periodic table is used as the metathesis polymerization catalyst, examples of the activity modifier include compounds that have the effect of reducing the metathesis polymerization catalyst, such as alcohols, haloalcohols, esters, ethers, nitriles, etc. Among these, alcohols and haloalcohols are preferred, and haloalcohols are more preferred.

[0077] Specific examples of alcohols include n-propanol, n-butanol, n-hexanol, 2-butanol, isobutyl alcohol, isopropyl alcohol, t-butyl alcohol, etc. Specific examples of haloalcohols include 1,3-dichloro-2-propanol, 2-chloroethanol, 1-chlorobutanol, etc.

[0078] Examples of activity modifiers, particularly when a ruthenium carbene complex is used as the metathesis polymerization catalyst, include Lewis base compounds. Examples of Lewis base compounds include phosphorus-containing Lewis base compounds such as tricyclopentylphosphine, tricyclohexylphosphine, triphenylphosphine, triphenylphosphite, and n-butylphosphine; and nitrogen-containing Lewis base compounds such as n-butylamine, pyridine, 4-vinylpyridine, acetonitrile, ethylenediamine, N-benzylidenemethylamine, pyrazine, piperidine, and imidazole. Furthermore, norbornenes substituted with alkenyl groups, such as vinylnorbornene, propenylnorbornene, and isopropenylnorbornene, function not only as polymerizable monomers but also as activity modifiers. The amount of these activity modifiers used can be adjusted appropriately depending on the compound used.

[0079] Examples of elastomers include natural rubber, polybutadiene, polyisoprene, styrene-butadiene copolymer (SBR), styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), ethylene-propylene-diene terpolymer (EPDM), ethylene-vinyl acetate copolymer (EVA), and hydrogenated versions of these. Dissolving an elastomer in the polymerizable composition allows for adjustment of its viscosity. Furthermore, adding an elastomer can improve the impact resistance of the norbornene-based resin formed by bulk polymerization of the composition. The amount of elastomer used is preferably 0.5 to 20 parts by mass, more preferably 2 to 10 parts by mass, per 100 parts by mass of the total amount of polymerizable monomers in the polymerizable composition.

[0080] Examples of antioxidants (antiaging agents) include various antioxidants for plastics and rubbers, such as phenolic, phosphorus-based, and amine-based antioxidants. As dispersants, anionic surfactants, cationic surfactants, and nonionic surfactants can be used as desired, with nonionic surfactants being preferred.

[0081] The polymerizable composition of the present invention is prepared by appropriately mixing the above-mentioned components according to a known method. The polymerizable composition of the present invention may also be prepared by preparing two or more premixed liquids and mixing the two or more premixed liquids using a mixing device or the like immediately before bulk polymerization to produce a norbornene-based resin. Each premixed liquid will not undergo bulk polymerization on its own, but the above-mentioned components are prepared by dividing them into two or more liquids so that mixing all the liquids results in a polymerizable composition containing each component in a predetermined ratio (the total content of each component is 100% by mass). That is, the polymerizable composition of the present invention may be a polymerizable composition consisting of two or more premixed liquids that do not undergo polymerization reaction alone and can be formed by combining these premixed liquids. The combination of two or more reactant liquids can be exemplified by the following two methods (a) and (b), depending on the type of metathesis polymerization catalyst used.

[0082] (a): The metathesis polymerization catalyst may be one that does not have polymerization activity by itself but exhibits polymerization activity when used in combination with an activator. In this case, a premixed liquid (liquid A) containing a polymerizable monomer containing a norbornene-based monomer and an activator and a premixed liquid (liquid B) containing a polymerizable monomer containing a norbornene-based monomer and a metathesis polymerization catalyst are used and mixed to obtain a polymerizable composition. Furthermore, a premixed liquid (liquid C) containing a polymerizable monomer containing a norbornene-based monomer but not containing a metathesis polymerization catalyst or an activator may also be used in combination.

[0083] (b): When a metathesis polymerization catalyst having polymerization activity by itself is used, a polymerizable composition can be obtained by mixing a premixed liquid (i) containing a polymerizable monomer including a norbornene-based monomer with a premixed liquid (ii) containing the metathesis polymerization catalyst. In this case, the premixed liquid (ii) is typically prepared by dissolving or dispersing the metathesis polymerization catalyst in a small amount of an inert solvent. Examples of such solvents include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and trimethylbenzene; ketones such as methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and 4-hydroxy-4-methyl-2-pentanone; cyclic ethers such as tetrahydrofuran; diethyl ether, dichloromethane, dimethyl sulfoxide, and ethyl acetate.

[0084] Optional components such as a radical generator, a diisocyanate compound, and a polyfunctional (meth)acrylate compound may be contained in any of the pre-mixed liquids, or may be added in the form of a mixed liquid other than the pre-mixed liquid.

[0085] Examples of the mixing device used to mix the pre-mixed liquid include an impingement mixer that is generally used in reaction injection molding, as well as low-pressure mixers such as a dynamic mixer and a static mixer.

[0086] <Resin-impregnated superconducting coil> The resin-impregnated superconducting coil of the present invention is a resin-impregnated superconducting coil used in a high-dose environment where the radiation exposure dose per 100,000 hours is 1 MGy or more, and is formed by impregnating a superconducting coil with a norbornene-based resin obtained by bulk polymerizing the polymerizable composition of the present invention described above. That is, the resin-impregnated superconducting coil of the present invention is a superconducting coil impregnated with a norbornene-based resin obtained by bulk polymerizing the polymerizable composition of the present invention.

[0087] Here, Fig. 1(A) is a schematic perspective view of a resin-impregnated superconducting coil 10 according to one embodiment of the present invention, and Fig. 1(B) is a schematic cross-sectional view of the resin-impregnated superconducting coil 10 according to one embodiment of the present invention. In the following, the resin-impregnated superconducting coil of the present invention will be explained using the resin-impregnated superconducting coil 10 according to one embodiment of the present invention shown in Figs. 1(A) and 1(B) as an example, but the present invention is not limited to the aspects shown in Figs. 1(A) and 1(B).

[0088] As shown in Fig. 1(A), the resin-impregnated superconducting coil 10 according to this embodiment includes a bobbin 20 and a winding body 30 formed around the bobbin 20. Fig. 1(B) is a cross-sectional view of the resin-impregnated superconducting coil 10 taken along line Ib-Ib in Fig. 1(A). As shown in Fig. 1(B), the winding body 30 includes a superconducting wire 32 and a wire protective layer 34.

[0089] The reel 20 is formed of, for example, a glass fiber reinforced composite material, a high-strength polyethylene fiber reinforced composite material, stainless steel, aluminum, or the like, and the superconducting wire 32 is concentrically wound around the reel 20. The wire protective layer 34 is a protective layer for protecting the superconducting wire 32, and in this embodiment, the wire protective layer 34 is made of a norbornene-based resin obtained by bulk polymerization of the above-described polymerizable composition of the present invention.

[0090] The resin-impregnated superconducting coil 10 may have an insulating plate on the upper and / or lower surface of the winding body 30 .

[0091] The resin-impregnated superconducting coil 10 of this embodiment can be manufactured by, for example, a first manufacturing method or a second manufacturing method described below.

[0092] That is, in the first manufacturing method, the superconducting wire 32 is wound around the reel 20 while being coated with the above-described polymerizable composition of the present invention, and then the polymerizable composition is polymerized and cured to manufacture the resin-impregnated superconducting coil 10.

[0093] The superconducting wire 32 may be made of, for example, a niobium-titanium alloy, an A15-type intermetallic compound (such as niobium-3-tin, niobium-3-aluminum, or vanadium-3-gallium), magnesium diboride, or yttrium-barium copper oxide (YBa ２ Cu ３ O ７ : YBCO) or gadolinium barium copper oxide (GdBa ２ Cu ３ O ７ Rare earth barium copper oxide (REBa: GdBCO) ２ Cu ３ O ７ :REBCO), bismuth strontium copper oxide (Bi ２ Sr ２ CaCuO X :Bi2212, Bi ２ Sr ２ Ca ２ Cu ３ O X Examples of the shape of the superconducting wire 32 include a round wire, a rectangular wire, a twisted wire, and a tape-shaped wire. Fig. 1(B) shows an example in which the superconducting wire 32 is a tape-shaped wire.

[0094] In addition, the superconducting wire 32 may have a multi-layer structure, for example, a configuration having a first stabilization layer, a substrate, an intermediate layer, a superconducting layer, a protective layer, and a second stabilization layer in this order.

[0095] The first stabilization layer can be made of a metal with a high specific heat, such as copper or aluminum, and the substrate can be made of a high-strength metal, such as a nickel-based alloy, stainless steel, or copper. The intermediate layer can have a laminated structure of multiple oxides, and the superconducting layer can be made of the above-mentioned superconducting material. The protective layer can be made of, for example, silver, gold, or platinum and can have the function of suppressing oxygen diffusion from the superconducting layer. The second stabilization layer can be made of a metal with a high specific heat, such as copper or aluminum.

[0096] The polymerizable composition can be applied to the superconducting wire 32, for example, by continuously conveying the superconducting wire 32 from a delivery means using rollers and passing the superconducting wire 32 through the polymerizable composition. The conveying speed of the superconducting wire 32 may be appropriately adjusted so that the polymerizable composition sufficiently adheres to the surface of the superconducting wire 32.

[0097] The polymerizable composition can be prepared by separately introducing the two or more premixed liquids into an impingement mixer, bringing them into contact with each other, and mixing them. Examples of the mixer that can be used include an impingement mixer for reaction injection molding (RIM), and low-pressure mixers such as a dynamic mixer or a static mixer. The prepared polymerizable composition can be stored in a suitable tank or the like for use in passing the superconducting wire 32 through the polymerizable composition. Although the polymerizable composition may gradually thicken, from the viewpoint of uniformly applying the polymerizable composition to the superconducting wire 32, it is desirable to pass the superconducting wire 32 through the polymerizable composition within a time period shorter than the usable time of the polymerizable composition (the time from the time the polymerizable composition is obtained until the polymerizable composition changes from a liquid state to a pudding-like state and no longer flows, also referred to as the pot life).

[0098] The superconducting wire 32 that has passed through the polymerizable composition is then wound up on a reel 20, and the polymerizable composition is then polymerized and cured by bulk polymerization, thereby obtaining a resin-impregnated superconducting coil 10.

[0099] If the superconducting wire 32 does not have an insulating layer on its surface, it is preferable to ensure circumferential insulation between the superconducting wires 32 by wrapping insulating tape around the superconducting wire 32 in advance, or to ensure circumferential insulation between the superconducting wires 32 by inserting insulating sheets between the superconducting wires 32 when winding the superconducting wire 32 around the reel 20. Examples of materials for the insulating tape or insulating sheet include polyimide and aramid fiber paper. Alternatively, paraffin, wax, grease, or the like may be applied to the surface of the superconducting wire 32 in advance.

[0100] The polymerizable composition that has been wound together with the superconducting wire 32 and that has impregnated or adhered between or on the surface of the superconducting wire 32 can be polymerized and cured by, for example, placing the composition in a mold formed of a male mold and a female mold and heating it, after optionally drying it. The heating temperature is preferably 10 to 150°C, more preferably 30 to 120°C, and even more preferably 50 to 100°C, and the heating time is preferably 20 seconds to 20 minutes, more preferably 20 seconds to 5 minutes. During heating, if desired, nitrogen gas may be sealed in the mold, and a pressure of preferably 0.1 to 1 MPa may be applied. After heating is complete, the mold is opened and demolded to obtain the resin-impregnated superconducting coil 10.

[0101] Alternatively, the following method can be employed as the second manufacturing method: In the second manufacturing method, superconducting wire 32 is wound around reel 20 without being impregnated with the polymerizable composition, and while superconducting wire 32 is wound around reel 20, the polymerizable composition is impregnated into superconducting wire 32, and the polymerizable composition is then polymerized and cured to manufacture resin-impregnated superconducting coil 10.

[0102] The superconducting wire 32 wound around the reel 20 can be impregnated with the polymerizable composition by various methods. For example, as in the first manufacturing method described above, the obtained polymerizable composition can be stored in a tank or the like, and the superconducting wire 32 wound around the reel 20 can be immersed therein and maintained for a certain period of time. In this case, the impregnation with the polymerizable composition can be performed while removing air and the like by drawing a vacuum and degassing under reduced pressure when the superconducting wire 32 is immersed. Alternatively, the impregnation can be performed under pressure by sealing in nitrogen gas. Alternatively, the superconducting wire 32 wound around the reel 20 can be placed in a mold formed by a male mold and a female mold, and the polymerizable composition can be injected into the mold while removing air and the like by drawing a vacuum and degassing under reduced pressure. Alternatively, after the injection of the polymerizable composition, the impregnation can be performed under pressure by sealing in nitrogen gas. The pressure at which the polymerizable composition is impregnated into the superconducting wire 32 wound around the bobbin 20 is preferably 0.1 to 1 MPa.

[0103] The polymerization and hardening of the polymerizable composition impregnated into the superconducting wire 32 wound around the reel 20 can be carried out in the same manner as in the first manufacturing method described above. In the second manufacturing method as well, after heating is completed, the mold is opened and demolded to obtain the resin-impregnated superconducting coil 10.

[0104] As described above, the resin-impregnated superconducting coil 10 can be obtained by the first manufacturing method or the second manufacturing method. Alternatively, the resin-impregnated superconducting coil 10 of this embodiment can also be manufactured by, for example, impregnating an insulating tape or an insulating sheet to be used when winding the superconducting wire 32 with the polymerizable composition of the present invention in advance to form a prepreg, and then winding this prepreg around the superconducting wire 32 in advance, or by inserting the prepreg between the superconducting wires 32 when winding the superconducting wire 32 around the reel 20, and then heating the prepreg to polymerize and harden the polymerizable composition after winding the superconducting wire 32.

[0105] The specifications of the resin-impregnated superconducting coil 10 of this embodiment are not particularly limited, but may be, for example, an inner diameter of 30 to 400 mm, an outer diameter of 100 to 1000 mm, and the number of turns in the range of 100 to 5000.

[0106] The resin-impregnated superconducting coil 10 of this embodiment includes a norbornene-based resin obtained by bulk polymerization of the above-described polymerizable composition of the present invention. The norbornene-based resin obtained using the polymerizable composition of the present invention has excellent durability in the above-described high-dose environment. Therefore, the resin-impregnated superconducting coil manufactured using the polymerizable composition of the present invention can be used stably for a long period of time in a high-dose environment.

[0107] Furthermore, the norbornene-based resin obtained using the polymerizable composition of the present invention has excellent mechanical properties even at extremely low temperatures, but has a property of relatively weak adhesive strength with the superconducting wire 32 that constitutes the resin-impregnated superconducting coil 10. Therefore, even if thermal shrinkage of the norbornene-based resin occurs during cooling, the resin-impregnated superconducting coil 10 can be prevented from being broken by tensile stress caused by the thermal shrinkage, and as a result, the occurrence of quenching can be effectively suppressed.

[0108] Furthermore, norbornene-based resins obtained using the polymerizable composition of the present invention contain rare-earth element-containing particles. Because rare-earth element-containing particles have excellent heat storage properties, norbornene-based resins obtained using the polymerizable composition of the present invention can exhibit high specific heat at extremely low temperatures, thereby effectively suppressing quenching. Additionally, the rare-earth element-containing particles can absorb generated heat and mitigate temperature rise, thereby effectively suppressing thermal runaway in resin-impregnated superconducting coils. Specifically, norbornene-based resins obtained using the polymerizable composition of the present invention can exhibit high specific heat at a temperature of 4 K, preferably 3.0 J / K / kg or more, more preferably 5.0 J / K / kg or more, even more preferably 10.0 J / K / kg or more, and particularly preferably 15.0 J / K / kg or more. The upper limit of the specific heat of norbornene-based resins at a temperature of 4 K is not particularly limited, but is, for example, 100 J / K / kg or less.

[0109] Taking advantage of these characteristics, the resin-impregnated superconducting coil 10 of this embodiment can be suitably used as a resin-impregnated superconducting coil used in a high-dose environment where the radiation exposure amount per 100,000 hours falls within the above-mentioned range. Specifically, the resin-impregnated superconducting coil 10 of this embodiment can be suitably used as a superconducting coil for generating a magnetic field in a particle accelerator such as SuperKEKB.

[0110] The present invention will be described below based on examples, but the present invention is not limited to these examples. Note that "parts" and "%" are by mass unless otherwise specified.

[0111] <Flexural Strength> Flexural strength of the norbornene-based resin was measured at 23° C. in accordance with JIS K7017 before and after gamma-ray irradiation.

[0112] Example 1: 100 parts of RIM monomer (manufactured by Zeon Corporation), Gd ２ O ３A preliminary blend solution (i) was obtained by mixing 500 parts of the particles, 1.5 parts of coupling agent 1 (vinyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts of coupling agent 2 (bicycloheptenylethyltriethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.), and 3 parts of a dispersant (product name "Rheodol SP-030V", isopropyl tristearoyl titanate, manufactured by Kao Corporation). The RIM monomer contains 90 parts of dicyclopentadiene and 10 parts of tricyclopentadiene as norbornene-based monomers.

[0113] A pre-blended solution (ii) was obtained by dissolving 0.3 parts of a ruthenium catalyst represented by formula (7) as a metathesis polymerization catalyst, 30 parts of 2,6-di-t-butyl-p-cresol (BHT, antioxidant), and 30 parts of triphenylphosphine in 39.7 parts of cyclopentanone. (In the formula, Mes represents a mesityl group.)

[0114] The mold used was a flat-plate reaction injection mold consisting of two stainless steel plates with an internal space of 245 mm length x 210 mm width x 4 mm thickness. This reaction injection mold had a structure in which a reaction liquid injection hole was provided at the bottom of one of the stainless steel plates.

[0115] The pre-mixture liquids (i) and (ii) prepared above were mixed in a ratio of (i):(ii) = 600:1 (mass ratio), degassed in a vacuum, and then injected into a reaction injection mold through the reaction liquid injection port. The mixture was heated in an oven heated to 40°C for 30 minutes, and then heated at 120°C for 60 minutes to obtain a polymerized and cured norbornene-based resin. The bending strength of the obtained norbornene-based resin (before gamma-ray irradiation) was measured according to the method described above. The results are shown in Table 1.

[0116] Similarly, two norbornene-based resins were obtained. Then, using gamma-ray irradiation equipment (the Takasaki Institute of Quantum and Radiological Science and Technology Cobalt-60 Irradiation Facility, with a radiation exposure dose of 1 MGy or more per 100,000 hours), one of the obtained norbornene-based resins was irradiated with gamma rays at approximately 3 to 4 MGy, and the other was irradiated with gamma rays at approximately 5 MGy, to obtain a norbornene-based resin after gamma-ray irradiation. The specific gamma-ray exposure dose is shown in Table 1. The bending strength of the gamma-ray-irradiated norbornene-based resin was measured according to the method described above. The results are shown in Table 1.

[0117] Example 2: Gd ２ O ３ Instead of particles, Gd ２ O ２ Except for using S particles, a norbornene-based resin was obtained in the same manner as in Example 1, and tests were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0118] Example 3: Gd ２ O ３ Instead of particles, HoCu particles having a mode diameter of 1.1 μm on a number basis measured by a light scattering method (laser diffraction / scattering method) were used. ２ Except for using particles, a norbornene-based resin was obtained in the same manner as in Example 1, and tests were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0119] The polymerizable compositions obtained in Examples 1 to 3 had low viscosity, and when applied to a superconducting coil, exhibited sufficient impregnation properties for the superconducting coil, and therefore could be suitably used for producing a resin-impregnated superconducting coil.

[0120]

[0121] As is clear from Table 1, the polymerizable compositions of Examples 1 to 3 were able to provide norbornene-based resins having sufficient bending strength both when irradiated with gamma rays at approximately 3 to 4 MGy and when irradiated with gamma rays at approximately 5 MGy. Therefore, it was confirmed that a polymerizable composition containing a norbornene-based monomer, rare earth element-containing particles, and a metathesis polymerization catalyst can be used to produce a resin-impregnated superconducting coil having excellent durability in a high-dose environment (a high-dose environment in which the radiation exposure per 100,000 hours is 1 MGy or more).

[0122] Furthermore, the resulting norbornene-based resin has excellent mechanical properties even at extremely low temperatures, and also has the property of having a relatively low adhesive strength to the material constituting the windings of the superconducting coil. Therefore, even if the norbornene-based resin undergoes thermal contraction during cooling of the superconducting coil, the occurrence of damage to the superconducting coil due to tensile stress caused by the thermal contraction can be suppressed, and the occurrence of quenching can be effectively suppressed.

[0123] Additionally, the specific heat of the norbornene-based resin of Example 1 was measured at a temperature of 4 K using a physical property evaluation system (product name "PPMS," manufactured by Nippon Quantum Design Co., Ltd.) as a measuring device. As a result, the norbornene-based resin of Example 1 had a high specific heat of 20 J / K / kg at a temperature of 4 K. Therefore, when applied to a superconducting coil, the norbornene-based resin of Example 1 can effectively suppress the occurrence of quenching due to its excellent heat storage properties. Furthermore, it absorbs generated heat to mitigate temperature rise, and as a result, can effectively suppress the occurrence of thermal runaway, thereby obtaining a resin-impregnated superconducting coil with high current stability and excellent reliability. Furthermore, the norbornene-based resin of Example 1 also has excellent heat dissipation properties, and the resulting resin-impregnated superconducting coil can be cooled in a short time.

[0124] REFERENCE SIGNS LIST 10...resin-impregnated superconducting coil 20...winding frame 30...winding body 32...superconducting wire 34...wire protection layer

Claims

1. A polymerizable composition for resin-impregnated superconducting coils used in high-dose environments where the radiation exposure dose per 100,000 hours is 1 MGy or more, A polymerizable composition comprising norbornene monomers, rare earth element-containing particles, and a metathesis polymerization catalyst.

2. The polymerizable composition according to claim 1, wherein the rare earth element-containing particles contain at least one rare earth element selected from cerium, praseodymium, gadolinium, dysprosium, holmium, and erbium.

3. The polymerizable composition according to claim 1 or 2, wherein the content of the rare earth element-containing particles is 4 to 90% by mass.

4. The polymerizable composition according to claim 1 or 2, wherein the norbornene monomer contains 50% by mass or more of dicyclopentadiene.

5. The polymerizable composition according to claim 1 or 2, wherein the norbornene monomer comprises a tricyclic and a pentacyclic compound.

6. The polymerizable composition according to claim 1 or 2, further comprising a silane coupling agent.

7. A polymerizable composition according to claim 1 or 2, A polymerizable composition comprising two or more pre-compound solutions that do not undergo polymerization reactions individually, and which can form the polymerizable composition when the pre-compound solutions are combined.

8. The polymerizable composition according to claim 1 or 2, wherein the resin-impregnated superconducting coil is a superconducting coil for generating a magnetic field in a particle accelerator.

9. A resin-impregnated superconducting coil used in a high-dose environment where the radiation exposure dose per 100,000 hours is 1 MGy or more, A resin-impregnated superconducting coil is obtained by impregnating a superconducting coil with a norbornene-based resin obtained by bulk polymerizing the polymerizable composition according to claim 1 or 2.

10. The resin-impregnated superconducting coil according to claim 9, wherein the specific heat of the norbornene-based resin at a temperature of 4K is 3.0 J / K / kg or more.