Polymerizable composition and resin-impregnated superconducting coil

Abstract

Provided is a polymerizable composition comprising: a norbornene-based monomer; rare-earth element-containing particles having a number-based mode diameter of 0.05-1.5 μm (exclusive of 1.5); and a metathesis polymerization catalyst.

Description

[Technical Field]

[0001] The present invention relates to a polymerizable composition suitable for use in the manufacture of resin-impregnated superconducting coils that are highly reliable and can be cooled in a shorter time compared to conventional methods, and to a resin-impregnated superconducting coil obtained using such a polymerizable composition. [Background technology]

[0002] Superconducting coils are used in the superconducting equipment of nuclear magnetic resonance (NMR) devices, magnetic resonance imaging (MRI) devices, heavy ion beam therapy devices, and superconducting magnetic levitation railway vehicles, because they need to generate strong magnetic fields, and they are generally operated at extremely low temperatures of 20K (-253℃) or below.

[0003] Superconducting coils achieve a superconducting state by maintaining a temperature of around 4K (-269°C) using liquid helium as a coolant or conduction cooling with a refrigerator, allowing large currents to pass through with zero resistance and thereby generating a strong magnetic field. However, at temperatures around 4K, the specific heat of many materials decreases, making it easier for heat to enter from the outside. This thermal disturbance causes a localized rise in the temperature of the superconducting coil, initiating the formation of normal conduction spurts. While the superconducting coil can maintain its superconducting state once the normal conduction spurts are recooled back to around 4K, the propagation of normal conduction initiates a quench (a transition from superconductivity to normal conduction). The Joule heating generated in the quenched region instantaneously produces a large amount of heat, potentially leading to thermal runaway. When thermal runaway occurs, the superconducting coil can burn out, or the liquid helium coolant can vaporize significantly.

[0004] For example, Patent Document 1 describes a wire protection layer for protecting the superconducting wire constituting a superconducting coil, which is subjected to a temperature of 0.2 J / cm² in at least a portion of the temperature range between 4K and 40K. 3A technique is disclosed which is formed by a composition for a wire protection layer containing particles having a specific heat of K or more and a polymer material surrounding the particles. In this Patent Document 1, examples of the polymer material constituting the composition for the wire protection layer include epoxy resin, polyimide resin, phenol resin, urea resin, melamine resin, and the like.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the technique of Patent Document 1 above, the composition for forming the wire protection layer for protecting the superconducting wire has a high viscosity. Therefore, the impregnation into the superconducting coil may be incomplete, or peeling of the wire protection layer may occur due to the thermal shrinkage of the polymer material during cooling of the superconducting coil. As a result, suppression of the occurrence of thermal runaway may be insufficient, the current-carrying stability may not be ensured, and there may be a problem with the reliability of the superconducting coil. Further, in the technique of Patent Document 1 above, particles having a specific specific heat are used, but the specific heat is relatively high, so there is also a problem that heat tends to be trapped and it takes time to cool the superconducting coil. The present invention has been made in view of such a situation, and an object thereof is to provide a polymerizable composition suitably used for manufacturing a resin-impregnated superconducting coil having excellent reliability and capable of being cooled in a shorter time as compared with the conventional ones, and a resin-impregnated superconducting coil obtained by using such a polymerizable composition.

Means for Solving the Problems

[0007] The inventors conducted studies to achieve the above objective and found that the objective can be achieved by including rare earth element-containing particles having a predetermined particle size in a polymerizable composition containing norbornene monomers and a metathesis polymerization catalyst, thereby completing the present invention.

[0008] In other words, the present invention provides a polymerizable composition comprising a norbornene monomer, rare earth element-containing particles with a mode diameter of 0.05 μm or more and less than 1.5 μm on a number basis, and a metathesis polymerization catalyst.

[0009] In the polymerizable composition of the present invention, it is preferable that the rare earth element-containing particles contain at least one rare earth element selected from cerium, praseodymium, gadolinium, dysprosium, holmium, and erbium. In the polymerizable composition of the present invention, the content of the rare earth element-containing particles is preferably 4 to 90% by mass. When the content of the particles is within the above range, the resulting resin-impregnated superconducting coil has sufficient protective performance against the superconducting wire at a temperature of around 4K, and the composition has high fluidity when uncured, making it easy to impregnate the superconducting coil with resin, which is preferable. Preferably, the polymerizable composition of the present invention consists of two or more pre-compound solutions that do not undergo a polymerization reaction individually, and the polymerizable composition can be formed by combining the pre-compound solutions.

[0010] Furthermore, according to the present invention, a resin-impregnated superconducting coil is provided, which is obtained by impregnating a superconducting coil with a norbornene-based resin obtained by bulk polymerization of the above polymerizable composition. In the resin-impregnated superconducting coil of the present invention, it is preferable that the specific heat of the norbornene-based resin at a temperature of 4K is 3.0 J / K / kg or more. In the resin-impregnated superconducting coil of the present invention, it is preferable that the superconducting coil is a superconducting coil for generating a magnetic field in a nuclear magnetic resonance (NMR) apparatus, a magnetic resonance imaging (MRI) apparatus, or a heavy ion beam therapy device. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a polymerizable composition suitable for use in the manufacture of resin-impregnated superconducting coils that are highly reliable and can be cooled in a shorter time compared to conventional methods, and a resin-impregnated superconducting coil obtained using such a polymerizable composition. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1(A) is a schematic perspective view of a resin-impregnated superconducting coil according to one embodiment of the present invention, and Figure 1(B) is a schematic cross-sectional view of a resin-impregnated superconducting coil according to one embodiment of the present invention. [Modes for carrying out the invention]

[0013] <Polymerizable composition> The polymerizable composition of the present invention contains norbornene monomers, rare earth element-containing particles with a mode diameter of 0.05 μm or more and less than 1.5 μm on a number basis, and a metathesis polymerization catalyst.

[0014] The polymerizable composition of the present invention contains norbornene monomers and therefore has low viscosity. As a result, when the polymerizable composition of the present invention is applied to a superconducting coil, it exhibits sufficient impregnation properties for the superconducting coil. Therefore, the polymerizable composition of the present invention can be suitably used in the manufacture of resin-impregnated superconducting coils. Furthermore, the norbornene-based resin obtained using the polymerizable composition of the present invention has excellent mechanical properties even at extremely low temperatures, while also having relatively low adhesive strength to the superconducting wires constituting the superconducting coil. Therefore, even if thermal shrinkage of the norbornene-based resin occurs during cooling, the occurrence of failure of the superconducting coil due to tensile stress caused by thermal shrinkage can be suppressed, thereby effectively suppressing the occurrence of quenching caused by the failure of the superconducting coil. In addition, the polymerizable composition of the present invention contains rare earth element-containing particles with a mode diameter of 0.05 μm or more and less than 1.5 μm on a number basis. Since such rare earth element-containing particles have excellent heat storage properties, the norbornene-based resin obtained using the polymerizable composition of the present invention can exhibit high specific heat at cryogenic temperatures. This effectively suppresses the occurrence of quenching, and furthermore, the heat generated is absorbed and the temperature rise is mitigated by the action of such rare earth element-containing particles. In particular, the occurrence of thermal runaway can be effectively suppressed at cryogenic temperatures below 20K (-253°C), where the specific heat is low. Moreover, the rare earth element-containing particles used are extremely fine and have a large specific surface area. Due to their excellent heat dissipation effect, the resulting resin-impregnated superconducting coil can be cooled in a shorter time compared to conventional methods.

[0015] The norbornene monomer can be any compound having a norbornene ring structure and is not particularly limited, but examples include dicyclic monomers such as norbornene and norbornadiene; tricyclic monomers such as dicyclopentadiene; tetracyclic monomers such as tetracyclododecene; pentacyclic monomers such as tricyclopentadiene; heptacyclic monomers such as tetracyclopentadiene; and derivatives thereof having an alkenyl group with 2 to 10 carbon atoms, an alkynyl group with 2 to 10 carbon atoms, an alkylidene group with 1 to 10 carbon atoms, an epoxy group, or a (meth)acrylic group. The norbornene monomer can be used alone or in combination of two or more. From the viewpoint of further enhancing the effects of the present invention, the tricyclic monomer is preferred, and dicyclopentadiene is particularly preferred. The norbornene monomer used preferably contains 50% by mass or more of the tricyclic monomer, and among them dicyclopentadiene. Furthermore, it is also preferable to use both the tricyclic and pentacyclic monomers as norbornene monomers, in which case the mass ratio of "tricyclic:pentacyclic" is preferably 60:40 to 97:3, and more preferably 80:20 to 95:5.

[0016] The content of norbornene 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, even more preferably 70% by mass or more, and may be 100% by mass, based on 100% by mass of the total polymerizable monomer contained in the polymerizable composition. By setting the content of norbornene monomer within the above range, the norbornene resin obtained using the polymerizable composition of the present invention can have its adhesive strength to the superconducting wire constituting the superconducting coil sufficiently reduced while further improving its mechanical properties at cryogenic temperatures.

[0017] Furthermore, in the present invention, monocyclic cycloolefins may be used as polymerizable monomers to be contained in the polymerizable composition.

[0018] Monocyclic cycloolefins are not particularly limited, but include cyclobutene, cyclopentene, cyclohexene, cyclooctene, cyclododecene, cyclopentadiene, 1,4-cyclohexadiene, 1,5-cyclooctadiene, and derivatives thereof having a C2-C10 alkenyl group, a C2-C10 alkynyl group, a C1-C10 alkylidene group, an epoxy group, or a (meth)acrylic group. Monocyclic cycloolefins can be used individually or in combination of two or more.

[0019] Furthermore, the polymerizable composition of the present invention may contain, in addition to norbornene monomers and monocyclic cycloolefins, other polymerizable monomers that can polymerize with them. Examples of such other polymerizable monomers include other cycloolefin monomers.

[0020] The content of polymerizable monomers other than norbornene 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, out of 100% by mass of the total polymerizable monomers contained in the polymerizable composition, and may be 0% by mass.

[0021] Furthermore, the total content of polymerizable monomers, including norbornene monomers, in the polymerizable composition of the present invention is preferably 10 to 95% by mass, more preferably 15 to 93% by mass, and even more preferably 20 to 90% by mass, of 100% by mass of the entire polymerizable composition.

[0022] The rare earth element-containing particles used in this invention have a mode diameter in the range of 0.05 μm or more and less than 1.5 μm, based on the number of particles.

[0023] 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 it is preferable that they contain at least one rare earth element selected from cerium, praseodymium, gadolinium, dysprosium, holmium, and erbium. From the viewpoint of having a high specific heat and excellent heat storage properties, it is preferable that they contain at least one rare earth compound selected from CeCu6, CeAl2, HoCu2, Er3Ni, PrB6, PrCu2, DyCu2, GdCu2, Gd2O3, and Gd2O2S, and it is more preferable that they contain Gd2O3.

[0024] Furthermore, the rare earth element-containing particles used in the present invention may also further contain metal oxides such as silver oxide (Ag2O) and copper oxide (Cu2O), or metals such as bismuth (Bi) and lead (Pb).

[0025] The rare earth element-containing particles used in this invention have a number-based mode diameter in the range of 0.05 μm to less than 1.5 μm. The number-based mode diameter is the particle diameter with the highest probability of existence based on the number of particles. In a particle diameter distribution curve plotted on a number basis, where the frequency of existence of individual particle diameters is plotted against the logarithm of the particle diameters, the particle diameter showing the maximum value can be defined as the number-based mode diameter. By using rare earth element-containing particles with a number-based mode diameter in the range of 0.05 μm to less than 1.5 μm, such rare earth element-containing particles exhibit heat storage properties while being extremely fine, having a large specific surface area, and excellent heat dissipation properties. Therefore, when the polymerizable composition of this invention is applied to a superconducting coil, the resulting resin-impregnated superconducting coil can be cooled in a shorter time compared to conventional methods. The mode diameter of the rare earth element-containing particles used in this invention is preferably 0.07 to 1.3 μm, more preferably 0.1 to 1.2 μm, and even more preferably 0.7 to 1.1 μm. The mode diameter of the rare earth element-containing particles can be calculated, for example, by determining the particle size distribution converted to a number basis from the particle size distribution measured by the light scattering method (laser diffraction / scattering method).

[0026] The shape of the rare earth element-containing particles is not particularly limited, but examples include spherical, barrel-shaped, ellipsoidal, cylindrical, fibrous, and irregularly shaped particles, and a mixture of particles of multiple shapes may be used. For example, a combination of spherical and cylindrical rare earth element-containing particles may be used. Furthermore, the rare earth element-containing particles may be a mixture of two or more particles having different compositions.

[0027] Furthermore, the rare earth element-containing particles may be those in which a coating layer of a metal with high electrical and thermal conductivity is formed on the surface of particles of a rare earth element compound containing rare earth elements. Examples of such metals with high electrical and thermal conductivity include silver, gold, nickel, or copper.

[0028] The rare earth element-containing particles used in this invention may have their surfaces hydrophobic. By using hydrophobically treated rare earth element-containing particles, aggregation and sedimentation of the particles can be prevented in the polymerizable composition, and the dispersion of the particles can be made uniform in the norbornene-based resin obtained by bulk polymerization of the polymerizable composition. Examples of treatment agents used for hydrophobic treatment include silane coupling agents, titanate coupling agents, aluminum coupling agents, fatty acids such as stearic acid, oils and fats, surfactants, waxes, etc. These treatment agents can also be simply blended together with the rare earth element-containing particles in the polymerizable composition.

[0029] As the aforementioned processing agent, it is preferable to use a silane coupling agent having at least one hydrocarbon group having a norbornene structure, since even when rare earth element-containing particles are blended into the polymerizable composition, the viscosity remains low and the thixotropy (viscosity at rest) does not easily increase. Although this silane coupling agent can also function as a monomer, in the present invention it is treated as a silane coupling agent. Specific examples of such silane coupling agents include bicycloheptenyltrimethoxysilane, bicycloheptenyltriethoxysilane, bicycloheptenylethyltrimethoxysilane, and bicycloheptenylethyltriethoxysilane. Each of the aforementioned treatment agents can be used individually or in combination of two or more. The content of the treatment 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.

[0030] The content of rare earth element-containing particles in the polymerizable composition of the present invention is preferably 4 to 90% by mass, more preferably 7 to 85% by mass, even more preferably 10 to 84% by mass, even more preferably 70 to 83% by mass, and particularly preferably 75 to 82% by mass, based on 100% by mass of the entire polymerizable composition. By setting the content of rare earth element-containing particles within the above range, it is possible to achieve sufficient protection performance for superconducting wires while maintaining sufficiently high fluidity of the polymerizable composition in its uncured state.

[0031] The metathesis polymerization catalyst used in this invention is not particularly limited as long as it can perform ring-opening polymerization of norbornene monomers, and known catalysts can be used.

[0032] The metathesis polymerization catalyst used in the present invention is a complex formed by bonding a transition metal atom as the central atom with multiple ions, atoms, polyatomic ions, and / or compounds. As the transition metal atom, atoms from groups 5, 6, and 8 (long-period periodic table, the same applies hereinafter) are used. The atoms of each group are not particularly limited, but as a group 5 atom, for example, tantalum is used; as a group 6 atom, for example, molybdenum and tungsten are used; and as a group 8 atom, for example, ruthenium and osmium are used. Among these transition metal atoms, ruthenium and osmium from group 8 are preferred. That is, as the metathesis polymerization catalyst used in the present invention, a complex with ruthenium or osmium as the central atom is preferred, and a complex with ruthenium as the central atom is more preferred. As a complex with ruthenium as the central atom, a ruthenium carbene complex formed by coordinating a carbene compound to ruthenium is preferred. Here, "carbene compound" is a general term for compounds containing a methylene free radical, and refers to compounds with a divalent carbon atom (carbene carbon) that is uncharged, represented as (>C:). Ruthenium carbene complexes exhibit excellent catalytic activity during bulk ring-opening polymerization, resulting in polymers with less odor from unreacted monomers, leading to high productivity and the acquisition of high-quality polymers. Furthermore, they are relatively stable to oxygen and moisture in the air and are not easily deactivated, so they can be used in the atmosphere. Metathesis polymerization catalysts may be used individually or in combination of multiple types.

[0033] Examples of ruthenium carbene complexes include those represented by the following general formula (1) or general formula (2). [ka]

[0034] In the above general formulas (1) and (2), R 1and R 2 Each of these is independently a hydrogen atom; a halogen atom; or a C1-C20 organic group 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 substituents or may be bonded to each other to form a ring. 1 and R 2 Examples of groups that bond to each other to form a ring include indenylidene groups, such as phenylindenylidene groups, which may have substituents.

[0035] Specific examples of C1-C20 organic groups that may contain halogen atoms, oxygen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, or silicon atoms include C1-C20 alkyl groups, C2-C20 alkenyl groups, C2-C20 alkynyl groups, C6-C20 aryl groups, C1-C20 alkoxy groups, C2-C20 alkenyloxy groups, C2-C20 alkynyloxy groups, C6-C20 aryloxy groups, and C1-C8 Examples of C1-C20 organic groups include alkylthio groups, carbonyloxy groups, alkoxycarbonyl groups with 1 to 20 carbon atoms, alkylsulfonyl groups with 1 to 20 carbon atoms, alkylsulfonyl groups with 1 to 20 carbon atoms, alkylsulfonic acid groups with 1 to 20 carbon atoms, arylsulfonic acid groups with 6 to 20 carbon atoms, phosphonic acid groups, arylphosphonic acid groups with 6 to 20 carbon atoms, alkylammonium groups with 1 to 20 carbon atoms, and arylammonium groups with 6 to 20 carbon atoms. These C1-C20 organic groups, which may contain halogen atoms, oxygen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, or silicon atoms, may have substituents. Examples of substituents include C1-C10 alkyl groups, C1-C10 alkoxy groups, and C6-C10 aryl groups.

[0036] X 1 and X 2Each independently represents an arbitrary anionic ligand. An 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, a carboxyl group, and the like.

[0037] L 1 and L 2 represent a heteroatom-containing carbene compound or a neutral electron-donating compound other than the heteroatom-containing carbene compound. The heteroatom-containing carbene compound and the neutral electron-donating compound other than the heteroatom-containing carbene compound are compounds that have a neutral charge when separated from the central metal. From the viewpoint of improving catalytic activity, a heteroatom-containing carbene compound is preferred. A heteroatom means an atom of Group 15 and Group 16 of the periodic table, and specific examples thereof 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.

[0038] As the heteroatom-containing carbene compound, a compound represented by the following general formula (3) or (4) is preferred, and from the viewpoint of improving catalytic activity, a compound represented by the following general formula (3) is more preferred.

Chemical formula

[0039] 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 above general formulas (1) and (2). Also, R3 , R 4 , R 5 and R 6 These elements may be joined to each other in any combination to form a ring.

[0040] Furthermore, since the effects of the present invention become even more pronounced, R 5 and R 6 It is preferable that R is a hydrogen atom. 3 and R 4 The aryl group may have substituents, a phenyl group having an alkyl group with 1 to 10 carbon atoms as a substituent is more preferred, and a mesityl group is even more preferred.

[0041] Examples of the neutral electron-donating compounds include oxygen atoms, water, carbonyls, ethers, nitriles, esters, phosphines, phosphinites, phosphites, sulfoxides, thioethers, amides, imines, aromatics, cyclic diolefins, olefins, isocyanides, and thiocyanates.

[0042] In the above general formulas (1) and (2), R 1 , R 2 , X 1 , X 2 , L 1 and L 2 These elements may be used individually and / or combined with each other in any combination to form polydentate chelate ligands.

[0043] Furthermore, among the compounds represented by the above general formula (1) or (2), the ruthenium carbene complex used in the present invention is preferably the compound represented by the above general formula (1) in that the effects of the present invention are more pronounced, and more preferably the compound represented by the following general formula (5) or general formula (6).

[0044] The general formula (5) is shown below. [ka]

[0045] In the above general formula (5), Z is an oxygen atom, a sulfur atom, a selenium atom, NR 12 PR 12 Or AsR 12 And R 12 Z is 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 for Z because the effects of the present invention become even more pronounced.

[0046] Note, R 1 , R 2 , X 1 and L 1 The same applies as in the cases of general formulas (1) and (2) above, and each may form a polydentate chelate ligand individually and / or by combining with each other in any combination, but X 1 and L 1 It does not form a polydentate chelate ligand, and R 1 and R 2 It is preferable that these groups are bonded to each other to form a ring, more preferably they are indenylidene groups which may have substituents, and even more preferably they are phenylindenylidene groups. Furthermore, specific examples of organic groups having 1 to 20 carbon atoms that may contain halogen atoms, oxygen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, or silicon atoms are the same as in the cases of general formulas (1) and (2) above.

[0047] In the above general formula (5), R 7 and R 8Each of these groups is independently a hydrogen atom, a C1-C20 alkyl group, a C2-C20 alkenyl group, or a C6-C20 heteroaryl group. These groups may have substituents or may be bonded to each other to form a ring. Examples of substituents include a C1-C10 alkyl group, a C1-C10 alkoxy group, or a C6-C10 aryl group. When a ring is formed, it may be an aromatic ring, an alicyclic ring, or a heterocyclic ring. However, it is preferable to form an aromatic ring, more preferably an aromatic ring with C6-C20 atoms, and even more preferably an aromatic ring with C6-C10 atoms.

[0048] In the above general formula (5), R 9 , R 10 and R 11 Each of these is independently a hydrogen atom; a halogen atom; or a C1-C20 organic group 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 substituents and may be bonded to each other to form a ring. Specific examples of C1-C20 organic groups 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 in the cases of general formulas (1) and (2) above.

[0049] R 9 , R 10 and R 11 It 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.

[0050] Specific examples of compounds represented by the above general formula (5) and methods for producing them include, for example, those described in International Publication No. 03 / 062253 (JP 2005-515260).

[0051] The general formula (6) is shown below. [ka]

[0052] 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 is preferably a methylene group.

[0053] In the above general formula (6), [ka] The bond is either a single bond or a double bond, preferably a single bond.

[0054] R 1 , X 1 , X 2 and L 1 The same applies as in the cases of general formulas (1) and (2) above, and each may form a polydentate chelate ligand individually and / or by combining with each other in any combination, but X 1 , X 2 and L 1 It does not form a polydentate chelate ligand, and R 1 It is preferable that it is a hydrogen atom.

[0055] R 13 ~R 21 This is a hydrogen atom; a halogen atom; or a C1-C20 organic group 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 substituents and may be bonded to each other to form a ring. Specific examples of a C1-C20 organic group 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 in the cases of general formulas (1) and (2) above.

[0056] R 13 R is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. 14 ~R 17 is preferably a hydrogen atom, and R 18 ~R 21 This is preferably a hydrogen atom or a halogen atom.

[0057] Specific examples of compounds represented by the above general formula (6) and methods for producing them include, for example, those described in International Publication No. 11 / 079799 (JP 2013-516392).

[0058] The amount of 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, based on 1 mole of the total amount of polymerizable monomer used in the reaction.

[0059] Furthermore, the polymerizable composition of the present invention may optionally contain a radical generator, a diisocyanate compound, a polyfunctional (meth)acrylate compound, and other optional components.

[0060] Radical generators generate radicals upon heating, thereby inducing crosslinking reactions in norbornene-based resins formed by bulk polymerization. The sites where radical generators induce crosslinking reactions are mainly carbon-carbon double bonds contained in norbornene-based resins, but crosslinking may also occur at saturated bond sites. Examples of radical generators include organic peroxides, diazo compounds, and nonpolar radical generators.

[0061] The amount of 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 monomer used in the reaction.

[0062] Examples of diisocyanate compounds include 4,4'-methylenediphenyl diisocyanate (MDI), toluene-2,4-diisocyanate, 4-methoxy-1,3-phenylenediisocyanate, 4-isopropyl-1,3-phenylenediisocyanate, 4-chlor-1,3-phenylenediisocyanate, 4-butoxy-1,3-phenylenediisocyanate, 2,4-diisocyanate diphenyl ether, 1,4-phenylenediisocyanate, tolylenediisocyanate, xylylenediisocyanate (XDI), 1,5-naphthalenediisocyanate, benzidine diisocyanate, o-nitrobenzidine diisocyanate, and 4,4'-diisocyanate diphenyl ether. Examples include aromatic diisocyanate compounds such as oenzyl; 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; and polyurethane prepolymers obtained by reacting these diisocyanate compounds with low molecular weight polyols or polyamines such that the terminal ends are isocyanates. Furthermore, conventionally used and known polyfunctional isocyanate groups obtained by using these compounds as isocyanurates, biuret forms, adduct forms, or polymeric forms can be used without particular limitation. Examples of such compounds include 2,4-toluylene diisocyanate dimers, triphenylmethane triisocyanate, tris-(p-isocyanatephenyl)thiophosphite, polyfunctional aromatic isocyanate compounds, polyfunctional aromatic aliphatic isocyanate compounds, polyfunctional aliphatic isocyanate compounds, fatty acid-modified polyfunctional aliphatic isocyanate compounds, polyfunctional blocked polyfunctional aliphatic isocyanate compounds, polyfunctional blocked polyfunctional aliphatic isocyanate compounds, and polyisocyanate prepolymers.Among these, aromatic diisocyanate compounds, aliphatic diisocyanate compounds, and alicyclic diisocyanate compounds, which are polyfunctional non-blocking isocyanate compounds, are preferably used due to their excellent availability and ease of handling. These compounds can be used individually or in combination of two or more.

[0063] Polyfunctional blocked isocyanate compounds are those in which at least two isocyanate groups in the molecule are reacted with an active hydrogen-containing compound to make them inert at room temperature. These isocyanate compounds generally have a structure in which the isocyanate groups are masked by blocking agents such as alcohols, phenols, ε-caprolactam, oximes, and active methylene compounds. Polyfunctional blocked isocyanate compounds generally do not react at room temperature and therefore have excellent storage stability, but the isocyanate groups can be regenerated by heating to 140-200°C, allowing them to exhibit excellent reactivity.

[0064] The diisocyanate compounds may be used individually or in combination of two or more. The amount of 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, based on 100 parts by mass of the total amount of polymerizable monomer used in the reaction.

[0065] Furthermore, from the viewpoint of further improving the mechanical properties of norbornene-based resins obtained using the polymerizable composition of the present invention at cryogenic temperatures, polyfunctional (meth)acrylate compounds may be used. By using a polyfunctional (meth)acrylate compound together with a diisocyanate compound, the active hydrogen-reactive groups of the diisocyanate compound form chemical bonds with the hydroxyl groups present in the polyfunctional (meth)acrylate compound, thereby further enhancing the mechanical properties of norbornene-based resins at cryogenic temperatures. Preferred examples of polyfunctional (meth)acrylate compounds include ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and neopentyl glycol dimethacrylate.

[0066] The polyfunctional (meth)acrylate compounds may be used individually or in combination of two or more. The amount of 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, based on 100 parts by mass of the total amount of polymerizable monomer used in the reaction.

[0067] Other optional ingredients include surfactants, activity regulators, elastomers, antioxidants (anti-aging agents), and dispersants.

[0068] The activator is a compound that acts as a co-catalyst for the metathesis polymerization catalyst described above, thereby improving the polymerization activity of the catalyst. Examples of activators include alkylaluminum halides such as ethylaluminum dichloride and diethylaluminum chloride; alkoxyalkylaluminum halides obtained by substituting some of the alkyl groups of these alkylaluminum halides with alkoxy groups; and organotin compounds. The amount of activator used is not particularly limited, but is preferably 0.1 to 100 moles, and more preferably 1 to 10 moles, per mole of the total metathesis polymerization catalyst used in the polymerizable composition.

[0069] The activity regulator is used to prevent polymerization from starting prematurely when a polymerizable composition is prepared by mixing two or more reaction stocks, as described later, and then injected into a mold to initiate polymerization.

[0070] When using a transition metal compound from Group 5 or Group 6 of the periodic table as a metathesis polymerization catalyst, suitable activity regulators include compounds that reduce the metathesis polymerization catalyst, such as alcohols, haloalcohols, esters, ethers, and nitriles. Among these, alcohols and haloalcohols are preferred, with haloalcohols being more preferred.

[0071] Specific examples of alcohols include n-propanol, n-butanol, n-hexanol, 2-butanol, isobutyl alcohol, isopropyl alcohol, and t-butyl alcohol. Specific examples of haloalcohols include 1,3-dichloro-2-propanol, 2-chloroethanol, and 1-chlorobutanol.

[0072] Lewis base compounds are particularly suitable as activity regulators when using ruthenium carbene complexes as metathesis polymerization catalysts. Examples of Lewis base compounds include those containing phosphorus atoms, such as tricyclopentylphosphine, tricyclohexylphosphine, triphenylphosphine, triphenylphosphine, and n-butylphosphine; and those containing nitrogen atoms, such as n-butylamine, pyridine, 4-vinylpyridine, acetonitrile, ethylenediamine, N-benzylidenemethylamine, pyrazine, piperidine, and imidazole. Furthermore, norbornene substituted with alkenyl groups, such as vinylnorbornene, propenylnorbornene, and isopropenylnorbornene, are polymerizable monomers and also act as activity regulators. The amount of these activity regulators used should be appropriately adjusted depending on the compound being used.

[0073] 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 polymer (EPDM), ethylene-vinyl acetate copolymer (EVA), and their hydrides. The viscosity can be adjusted by dissolving the elastomer in the polymerizable composition. Furthermore, the impact resistance of the norbornene-based resin formed by the bulk polymerization of the composition can be improved by adding the elastomer. 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 monomer in the polymerizable composition.

[0074] Examples of antioxidants (anti-aging agents) include various antioxidants for plastics and rubbers, such as phenolic, phosphorus-based, and amine-based antioxidants. As a dispersant, anionic surfactants, cationic surfactants, and nonionic surfactants can be used as desired, but nonionic surfactants are preferred.

[0075] The polymerizable composition of the present invention is prepared by appropriately mixing the above components according to known methods. The polymerizable composition of the present invention may also be prepared by preparing two or more pre-compound solutions and mixing the two or more pre-compound solutions using a mixing device or the like immediately before bulk polymerization to obtain a norbornene-based resin. The pre-compound solutions are prepared by dividing the above components into two or more solutions so that bulk polymerization does not occur with just one solution, but when all solutions are mixed, a polymerizable composition containing each component in a predetermined proportion (total content of each component 100% by mass) is obtained. Two combinations of such two or more reaction stock solutions are given below, (a) and (b), depending on the type of metathesis polymerization catalyst used.

[0076] (a): As the metathesis polymerization catalyst, one can be used that does not have polymerization reaction activity on its own but exhibits polymerization reaction activity when used in combination with an activator. In this case, a polymerizable composition can be obtained by mixing a pre-compound solution (Solution A) containing a polymerizable monomer containing a norbornene monomer and an activator, and a pre-compound solution (Solution B) containing a polymerizable monomer containing a norbornene monomer and a metathesis polymerization catalyst. Furthermore, a pre-compound solution (Solution C) containing a polymerizable monomer containing a norbornene monomer, but not containing either a metathesis polymerization catalyst or an activator, may also be used in combination.

[0077] (b): When a metathesis polymerization catalyst that has polymerization reaction activity on its own is used, a polymerizable composition can be obtained by mixing a pre-compound solution (i) containing a polymerizable monomer including a norbornene monomer with a pre-compound solution (ii) containing a metathesis polymerization catalyst. In this case, the pre-compound solution (ii) is usually a solution in which the metathesis polymerization catalyst is dissolved or dispersed in a small amount of 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; and diethyl ether, dichloromethane, dimethyl sulfoxide, and ethyl acetate.

[0078] Any optional components such as radical generators, diisocyanate compounds, and polyfunctional (meth)acrylate compounds may be included in any of the aforementioned pre-compound solutions, or added in the form of a mixture other than the aforementioned pre-compound solutions.

[0079] Mixing equipment used for mixing the above-mentioned pre-mixed liquids includes, for example, impact mixing equipment commonly used in reaction injection molding, as well as low-pressure mixers such as dynamic mixers and static mixers.

[0080] <Resin-impregnated superconducting coil> The resin-impregnated superconducting coil of the present invention 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. In other words, 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.

[0081] Here, Figure 1(A) is a schematic perspective view of a resin-impregnated superconducting coil 10 according to one embodiment of the present invention, and Figure 1(B) is a schematic cross-sectional view of a 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 described using the resin-impregnated superconducting coil 10 according to one embodiment of the present invention shown in Figures 1(A) and 1(B) as an example, but the present invention is not limited in any way to the embodiments shown in Figures 1(A) and 1(B).

[0082] As shown in Figure 1(A), the resin-impregnated superconducting coil 10 according to this embodiment comprises a winding frame 20 and a winding body 30 formed around the winding frame 20. Figure 1(B) is a cross-sectional view of the resin-impregnated superconducting coil 10 along the Ib-Ib line in Figure 1(A). As shown in Figure 1(B), the winding body 30 comprises a superconducting wire 32 and a wire protection layer 34.

[0083] The reel frame 20 is formed from, for example, glass fiber reinforced composite material, high-strength polyethylene fiber reinforced composite material, stainless steel, or aluminum, and the superconducting wire 32 is wound concentrically around this reel frame 20. The wire protection layer 34 is a protective layer for protecting the superconducting wire 32, and in this embodiment, the wire protection layer 34 is made of a norbornene-based resin obtained by bulk polymerization of the polymerizable composition of the present invention described above.

[0084] Furthermore, the resin-impregnated superconducting coil 10 may be configured to have insulating plates on the upper and / or lower surfaces of the winding body 30.

[0085] The resin-impregnated superconducting coil 10 of this embodiment can be manufactured, for example, by the first manufacturing method or the second manufacturing method described below.

[0086] In other words, in the first manufacturing method, the superconducting wire 32 is wound on a winding frame 20 while the polymerizable composition of the present invention described above is applied to it, and then the polymerizable composition is polymerized and cured to produce a resin-impregnated superconducting coil 10.

[0087] As for the superconducting wire 32, for example, as a superconducting material, niobium titanium alloy, A15 type intermetallic compounds (niobium-tin, niobium-aluminum, vanadium-gallium, etc.), magnesium diboride, rare earth barium copper oxide (REBa2Cu3O7:REBCO) including yttrium barium copper oxide (YBa2Cu3O7:YBCO) or gadolinium barium copper oxide (GdBa2Cu3O7:GdBCO), bismuth strontium copper oxide (Bi2Sr2CaCu2O X :Bi2212,Bi2Sr2Ca2Cu3O X Examples include wires containing :Bi2223, etc. Furthermore, examples of the shape of the superconducting wire 32 include round wires, rectangular wires, stranded wires, and tape-shaped wires. Figure 1(B) shows an example where the superconducting wire 32 is a tape-shaped wire.

[0088] Furthermore, the superconducting wire 32 may have a multilayer structure, for example, a configuration in which the layers of a first stabilizing layer, a substrate, an intermediate layer, a superconducting layer, a protective layer, and a second stabilizing layer are arranged in this order.

[0089] The first stabilizing 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 nickel-based alloy, stainless steel, or a high-strength metal such as copper. The intermediate layer can be a laminated structure of multiple oxides, and the superconducting layer can be made of the superconducting material described above. Furthermore, the protective layer can be made of, for example, silver, gold, or platinum, and can have the function of suppressing the diffusion of oxygen from the superconducting layer, and the second stabilizing layer can be made of a metal with a high specific heat, such as copper or aluminum.

[0090] The polymerizable composition can be applied to the superconducting wire 32, for example, by continuously conveying the superconducting wire 32 from a feeding means using rollers and passing it through the polymerizable composition. The conveying speed of the superconducting wire 32 can be adjusted as appropriate so that the polymerizable composition adheres sufficiently to the surface of the superconducting wire 32.

[0091] The polymerizable composition can be prepared by separately introducing and contacting the two or more pre-mixing solutions described above into an impact mixing device and mixing them. As the mixing device, for example, an impact mixing device for reaction injection molding (RIM), or a low-pressure mixing device such as a dynamic mixer or static mixer can be used. The prepared polymerizable composition can be stored in any tank as appropriate for use in passing the superconducting wire 32. While the polymerizable composition may gradually thicken, from the viewpoint of uniformly coating the superconducting wire 32 with the polymerizable composition, it is desirable that the passage of the superconducting wire 32 through the polymerizable composition be less than the pot life (the time from the time the polymerizable composition is obtained until it changes from a liquid state to a pudding-like state and stops flowing; also called the pot life).

[0092] Then, the superconducting wire 32 that has passed through the polymerizable composition is wound up on the winding frame 20, and the polymerizable composition is polymerized and cured by bulk polymerization to obtain the resin-impregnated superconducting coil 10.

[0093] Furthermore, 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 pre-wrapping insulating tape around the superconducting wire 32, or to ensure circumferential insulation between the superconducting wires 32 by inserting an insulating sheet between the superconducting wires 32 when winding them on the winding frame 20. Examples of materials for the insulating tape or insulating sheet include polyimide and aramid fiber paper. Alternatively, paraffin, wax, or grease may be applied to the surface of the superconducting wire 32 in advance.

[0094] Polymerization and curing of the polymerizable composition, which is wound together with the superconducting wire 32 and impregnated and attached between the superconducting wires 32 or to the surface of the superconducting wires 32, can be carried out by drying as desired, then, for example, by placing it in a mold formed by a male and female mold and heating it. The heating temperature at this time 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. Furthermore, during heating, nitrogen gas may be sealed in the mold and pressurized to preferably 0.1 to 1 MPa may be applied as desired. After heating is complete, the mold can be opened and demolded to obtain the resin-impregnated superconducting coil 10.

[0095] Alternatively, the following method can be adopted as a second manufacturing method. In this second manufacturing method, the superconducting wire 32 is wound onto a reel 20 without being impregnated in the polymerizable composition, the polymerizable composition is impregnated into the superconducting wire 32 while it is wound onto the reel 20, and then the polymerizable composition is polymerized and cured to produce a resin-impregnated superconducting coil 10.

[0096] Impregnation of the polymerizable composition into the superconducting wire 32 wound on the reel 20 can be carried out by various methods. For example, as in the first manufacturing method described above, the obtained polymerizable composition can be stored in any tank, and the superconducting wire 32, wound on the reel 20, can be immersed in it and maintained for a certain period of time. In this case, the impregnation of the polymerizable composition may be carried out under reduced pressure by removing air, etc., when immersing the superconducting wire 32, or it may be carried out under pressure by sealing in nitrogen gas. Alternatively, the superconducting wire 32 wound on the reel 20 can be placed in a mold formed by a male and female mold, air, etc. can be removed under reduced pressure by vacuuming, and the polymerizable composition can be injected into the mold while degassing under reduced pressure, or it may be carried out under pressure by sealing in nitrogen gas after the injection of the polymerizable composition. The pressure used to impregnate the polymerizable composition into the superconducting wire 32 wound on the reel frame 20 is preferably 0.1 to 1 MPa.

[0097] Polymerization and curing of the polymerizable composition impregnated into the superconducting wire 32 wound on the reel 20 can be carried out in the same manner as the first manufacturing method described above. In the second manufacturing method as well, after heating is complete, the resin-impregnated superconducting coil 10 can be obtained by opening the mold and demolding.

[0098] As described above, a resin-impregnated superconducting coil 10 can be obtained by the first or second manufacturing method. However, in addition, for example, an insulating tape or insulating sheet used when winding the superconducting wire 32 can be pre-impregnated with the polymerizable composition of the present invention to form a prepreg, which can then be pre-wound onto the superconducting wire 32, or inserted between the superconducting wires 32 when winding the superconducting wires 32 on the winding frame 20, and after winding the superconducting wires 32, the polymerizable composition can be polymerized and cured by heating, thereby manufacturing the resin-impregnated superconducting coil 10 of this embodiment.

[0099] The specifications of the resin-impregnated superconducting coil 10 in this embodiment are not particularly limited, but for example, the inner diameter can be in the range of 30 to 400 mm, the outer diameter in the range of 100 to 1000 mm, and the number of turns in the range of 100 to 5000.

[0100] The resin-impregnated superconducting coil 10 of this embodiment comprises a norbornene-based resin obtained by bulk polymerization of the polymerizable composition of the present invention described above. The norbornene-based resin obtained using the polymerizable composition of the present invention has excellent mechanical properties even at extremely low temperatures, but has the characteristic of having relatively weak adhesive strength with the superconducting wire 32 constituting the resin-impregnated superconducting coil 10. Therefore, even if thermal shrinkage of the norbornene-based resin occurs during cooling, the occurrence of fracture of the resin-impregnated superconducting coil 10 due to tensile stress caused by thermal shrinkage can be suppressed, thereby effectively suppressing the occurrence of quenching. In addition, the polymerizable composition of the present invention has rare earth element-containing particles with a mode diameter of 0.05 μm or more and less than 1.5 μm on a number basis. Since such rare earth element-containing particles have excellent heat storage properties, the norbornene-based resin obtained using the polymerizable composition of the present invention can exhibit a high specific heat at extremely low temperatures. This effectively suppresses the occurrence of quenching, and furthermore, the heat generated is absorbed and the temperature rise is mitigated by the action of such rare earth element-containing particles, thereby effectively suppressing the occurrence of thermal runaway in the resin-impregnated superconducting coil 10. Specifically, the specific heat of the norbornene-based resin obtained using the polymerizable composition of the present invention at a temperature of 4K can be made to be 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 4K is not particularly limited, but for example, it is 100 J / K / kg or less. Furthermore, the rare earth element-containing particles contained in the polymerizable composition of the present invention are extremely fine and have a large specific surface area. Due to their excellent heat dissipation effect, the resin-impregnated superconducting coil 10 of this embodiment can be cooled in a short time.

[0101] Furthermore, the resin-impregnated superconducting coil 10 of this embodiment can be suitably used as a superconducting coil for generating magnetic fields in superconducting equipment of nuclear magnetic resonance (NMR) devices, magnetic resonance imaging (MRI) devices, heavy ion beam therapy devices, or superconducting magnetic levitation railway vehicles, taking advantage of these characteristics. [Examples]

[0102] The present invention will be described below based on examples, but the present invention is not limited in any way by these examples. Unless otherwise specified, "parts" and "%" are based on mass.

[0103] <Example 1> Preliminary formulation (i) was obtained by mixing 100 parts of RIM monomer (manufactured by Nippon Zeon Co., Ltd.), 500 parts of Gd2O3 particles with a mode diameter of 0.9 μm based on the number of particles measured by light scattering (laser diffraction / scattering method), 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 dispersant (product name "Leodol SP-030V", isopropyltrisstearoyl titanate, manufactured by Kao Corporation). The above RIM monomer contains 90 parts of dicyclopentadiene and 10 parts of tricyclopentadiene as norbornene monomers.

[0104] As a metathesis polymerization catalyst, 0.3 parts of the ruthenium catalyst shown in formula (7), 30 parts of 2,6-di-t-butyl-p-cresol (BHT, an antioxidant), and 30 parts of triphenylphosphine were dissolved in 39.7 parts of cyclopentanone to obtain a preliminary formulation (ii). [ka] (In the formula, Mes represents the mesityl group.)

[0105] The molding die used was a reaction injection molding die for flat plate molded products, consisting of two stainless steel plates with an internal space measuring 245 mm (length) x 210 mm (width) x 4 mm (thickness). This reaction injection molding die has a reaction liquid injection hole at the bottom of one of the stainless steel plates.

[0106] Then, the preliminary formulations (i) and (ii) prepared above were mixed in a ratio of (i):(ii)=600:1 (mass ratio), degassed under vacuum, and injected into a reaction injection mold through the reaction solution injection hole. The mixture was then heated in an oven preheated to 40°C for 30 minutes, followed by heating at 120°C for 60 minutes to obtain a polymerized and cured norbornene-based resin.

[0107] The specific heat of the obtained norbornene-based resin at a temperature of 4K was measured using a physical properties evaluation system (product name "PPMS", manufactured by Nippon Quantum Design Co., Ltd.) as the 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 4K. 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, and furthermore, it can absorb the generated heat and mitigate the temperature rise, thereby effectively suppressing the occurrence of thermal runaway. As a result, a highly reliable resin-impregnated superconducting coil with high current-conducting stability can be obtained. In addition, 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.

[0108] Furthermore, the polymerizable composition obtained in Example 1 has low viscosity and exhibits sufficient impregnation properties when applied to a superconducting coil, making it suitable for use in the manufacture of resin-impregnated superconducting coils. The obtained norbornene-based resin has excellent mechanical properties even at cryogenic temperatures, and also has relatively low adhesive strength to the materials constituting the windings of the superconducting coil. Even if thermal shrinkage of the norbornene-based resin occurs during cooling, it can suppress the occurrence of superconducting coil failure due to tensile stress caused by thermal shrinkage. These factors also contribute to effectively suppressing quenching caused by superconducting coil failure. [Explanation of Symbols]

[0109] 10…Resin-impregnated superconducting coil 20... Volume frame 30... Winding 32…Superconducting wires 34...Wire protective layer

Claims

1. A polymerizable composition comprising norbornene monomers, rare earth element-containing particles with a mode diameter of 0.05 μm or more and less than 1.5 μm on a number basis, 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. A resin-impregnated superconducting coil is obtained by impregnating a superconducting coil with a norbornene-based resin obtained by bulk polymerization of a polymerizable composition according to any one of claims 1 to 3.

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

6. The resin-impregnated superconducting coil according to claim 4 or 5, wherein the superconducting coil is a superconducting coil for generating a magnetic field in a nuclear magnetic resonance apparatus (NMR), a magnetic resonance imaging apparatus (MRI), or a heavy ion beam therapy device.

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