Resin-coated superconducting wire, superconducting coil, and shield coil

Abstract

To provide a resin coated superconducting wire that is light in weight, highly flexible, and inexpensive as compared to conventional ones.SOLUTION: A resin coated superconducting wire includes a matrix resin comprising a synthetic resin material, and a superconducting wire extending in the matrix resin, wherein, in a transverse cross section of the resin coated superconducting wire, a cross-sectional area of the matrix resin is equal to or larger than a cross-sectional area of the superconducting wire.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a resin-coated superconducting wire, a superconducting coil, and a shield coil. [Background technology]

[0002] Superconducting materials have traditionally been used as shielding coils in devices such as nuclear magnetic resonance (NMR) devices and magnetic resonance imaging (MRI) examination devices to block magnetic fields from the outside to the inside to obtain appropriate analysis results, and to block magnetic fields from the inside to the outside to suppress their effects on the human body, electronic devices, etc.

[0003] As an example of such a superconducting material, as shown in Fig. 6, there is a resin-coated superconducting wire 2 in which a superconducting wire 22 such as an NbTi wire is coated with stabilizing copper 21 called a copper channel, and the periphery of the copper channel is further coated with a braid of resin such as polyester 23. In such a resin-coated superconducting wire 2, by coating the periphery of the superconducting wire 22 with stabilizing copper 21, heat generated from the superconducting wire 22 is dissipated to the outside, and the temperature rise is suppressed by cooling the wire by, for example, immersing it in liquid helium.

[0004] Furthermore, in order to increase the heat generation efficiency of superconducting materials, Patent Document 1 proposes a superconducting wire in which multiple superconducting wires are embedded in stabilizing copper, coated with resin, and further embedded in stabilizing copper. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2017-533579 Summary of the Invention [Problem to be solved by the invention]

[0006] However, all of the conventional superconducting materials mentioned above use a high-purity metal such as stabilized copper around the superconducting wire, which makes them relatively expensive and heavy, and they are also difficult to handle because they tend to bend easily.

[0007] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a resin-coated superconducting wire that is lighter, more flexible, and less expensive than conventional wires. [Means for solving the problem]

[0008] [1] A resin-coated superconducting wire having a matrix resin made of a synthetic resin material and a superconducting wire extending into the matrix resin, characterized in that, when viewed in cross section of the resin-coated superconducting wire, the cross-sectional area of ​​the matrix resin is equal to or greater than the cross-sectional area of ​​the superconducting wire. [2] The resin-coated superconducting wire according to [1] above, characterized in that the superconducting wire is made of one or more materials selected from the group consisting of metal / niobium titanium, metal / niobium tritin, metal / magnesium diboride, rare earth-based and bismuth-based superconducting materials. [3] The resin-coated superconducting wire according to [1] or [2] above, characterized in that the synthetic resin material is a thermoplastic resin. [4] The resin-coated superconducting wire according to [3] above, characterized in that the melting point of the thermoplastic resin is 290°C or lower. [5] The resin-coated superconducting wire according to [3] or [4] above, characterized in that the melting point of the thermoplastic resin is 210°C or lower. [6] The resin-coated superconducting wire according to any one of the above [1] to [5], wherein the synthetic resin material is polyamide or polyolefin. [7] The resin-coated superconducting wire according to [6] above, characterized in that the polyamide is nylon. [8] The resin-coated superconducting wire according to any one of the above [1] to [7], characterized in that the synthetic resin material is nylon 11, nylon 12 or polyethylene. [9] The resin-coated superconducting wire according to any one of the above [1] to [5], wherein the synthetic resin material is an amorphous resin having a glass transition point of 250° C. or lower.

[10] The resin-coated superconducting wire according to any one of the above [1] to [9], characterized in that the resin-coated superconducting wire is a multi-layer coated wire, in which the matrix resin is composed of two or more matrix resin layers, each of which is composed of an inner matrix resin layer covering the outer periphery of the superconducting wire and one or more outer matrix resin layers covering the outside of the inner matrix resin layer.

[11] The resin-coated superconducting wire according to

[10] above, characterized in that the inner matrix resin layer is an olefin-based resin containing at least one functional group selected from the group consisting of an epoxy group, an oxazolyl group, an amino group, and a maleic anhydride residue, or a copolymer thereof.

[12] The resin-coated superconducting wire according to

[10] above, wherein the inner matrix resin layer is an olefin-based copolymer containing a metal salt of a carboxylic acid.

[13] The resin-coated superconducting wire according to any one of the above [1] to

[12] , wherein the superconducting wire is a single wire.

[14] The resin-coated superconducting wire according to any one of the above [1] to

[12] , wherein the superconducting wire is a stranded wire.

[15] The resin-coated superconducting wire according to any one of the above [1] to

[14] , wherein the resin-coated superconducting wire has a rectangular cross-sectional shape.

[16] The resin-coated superconducting wire according to any one of the above [1] to

[14] , wherein the resin-coated superconducting wire has a circular cross-sectional shape.

[17] A resin-coated superconducting wire according to any one of the above [1] to

[16] , characterized in that the resin-coated superconducting wire has a dimensional precision of width and thickness of ±0.10 mm or less.

[18] A resin-coated superconducting wire according to any one of the above [1] to

[17] , characterized in that the dimensional precision of the width and thickness of the resin-coated superconducting wire is ±0.05 mm or less.

[19] A superconducting coil using the resin-coated superconducting wire according to any one of the above [1] to

[18] .

[20] A shield coil using the resin-coated superconducting wire according to any one of [1] to

[18] above. Effect of the Invention

[0009] According to the present disclosure, it is possible to provide a resin-coated superconducting wire that is lighter, more flexible, and less expensive than conventional wires. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view of a resin-coated superconducting wire (rectangular shape) according to one embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of a resin-coated superconducting wire (circular shape) according to one embodiment. [Diagram 3] FIG. 3 is a cross-sectional view of a resin-coated superconducting wire (rectangular shape) according to one embodiment. [Figure 4] FIG. 4 is a cross-sectional view of a resin-coated superconducting wire (circular shape) according to one embodiment. [Diagram 5] 5(a) to 5(f) are cross-sectional views showing various modified examples of resin-coated superconducting wires (rectangular shape). [Figure 6] FIG. 6 is a cross-sectional view of a conventional resin-coated superconducting wire. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Preferred embodiments of the present disclosure will be described in detail below, but the present disclosure is not limited to the following embodiments.

[0012] The present inventors have discovered that a resin-coated superconducting wire has a matrix resin made of a synthetic resin material and a superconducting wire extending into the matrix resin, and when viewed in cross section of the resin-coated superconducting wire, the cross-sectional area of ​​the matrix resin is equal to or greater than the cross-sectional area of ​​the superconducting wire, thereby making it possible to provide a resin-coated superconducting wire that is lighter, more flexible, and less expensive than conventional wires, and have thus completed the present disclosure.

[0013] 1. Resin-coated superconducting wire The resin-coated superconducting wire according to the present disclosure includes a matrix resin made of a synthetic resin material and a superconducting wire extending in the matrix resin, and in the resin-coated superconducting wire, the cross-sectional area of ​​the matrix resin is equal to or larger than the cross-sectional area of ​​the superconducting wire when viewed in a cross section of the resin-coated superconducting wire.

[0014] FIG. 1 is a cross-sectional view of a resin-coated superconducting wire of an embodiment, and FIG. 2 is a cross-sectional view of a resin-coated superconducting wire of an embodiment. As shown in FIGS. 1 and 2, a resin-coated superconducting wire 1 has a matrix resin 11 made of a synthetic resin material and a superconducting wire 12 extending in the matrix resin 11. In this embodiment, the cross-sectional area of ​​the matrix resin 11 is equal to or larger than the cross-sectional area of ​​the superconducting wire 12 when viewed in the cross section of the resin-coated superconducting wire 1. Note that FIG. 1 shows the resin-coated superconducting wire 1 having a rectangular cross-sectional shape, and FIG. 2 shows the resin-coated superconducting wire 1 having a circular cross-sectional shape. The resin-coated superconducting wire 1 shown in FIGS. 1 and 2 is a single-layer coated wire in which the matrix resin 11 composed of a single matrix resin layer covers the outer periphery of the superconducting wire 12.

[0015] In the application of the shield coil, the current flowing inside the superconducting wire 12 constituting the resin-coated superconducting wire 1 is relatively small. Therefore, the superconducting wire 12 used for such an application is unlikely to quench, and even if it does quench, the current is small, so there is no need to compound a large amount of stabilizing copper. On the other hand, in order to ensure the magnetic field blocking properties of the shield coil, it is necessary to arrange adjacent superconducting wires 12, 12 at a certain distance from each other when the resin-coated superconducting wire 1 is wound as a coil. Therefore, the superconducting wire 12 is extended (preferably embedded) in a matrix resin 11 having a cross-sectional area equal to or larger than that of the superconducting wire 12. As a result, in the resin-coated superconducting wire, the matrix resin 11 plays the role of a so-called spacer, and adjacent superconducting wires 12, 12 can be arranged at a certain distance from each other.

[0016] [Matrix resin] The matrix resin 11 is made of a synthetic resin material. The matrix resin 11 ensures insulation between the superconducting wires 12 and also plays the role of a so-called spacer as described above, arranging the adjacent superconducting wires 12 at a certain distance from each other. The matrix resin is in a solid form, and does not include those made of braided threads.

[0017] The matrix resin 11 is preferably a thermoplastic resin that can be extruded, which is an effective method for forming a thick coating so that the cross-sectional area of ​​the matrix resin 11 is equal to or greater than the cross-sectional area of ​​the superconducting wire 12, as viewed in the cross section of the resin-coated superconducting wire 1, and is more preferably a polyamide or polyolefin. The polyamide is preferably nylon. Examples of the above-mentioned thermoplastic resin include polyethylene, polypropylene, polystyrene, nylon 11, nylon 12, nylon 6, nylon 66, nylon 610, nylon MXD6 (a polycondensate of metaxylylenediamine and adipic acid), polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP), tetrafluoroethylene-ethylene copolymer resin (ETFE), polycarbonate, polyphenylene ether, polyetherimide, polyethersulfone, and the like, and these resins may be a single resin or a mixture of two or more types of resins.

[0018] The synthetic resin material constituting the matrix resin 11 includes not only those consisting of synthetic resins but also resin compositions mainly consisting of synthetic resins. The resin compositions may contain various additives contained in normal resin compositions, such as various fillers and antioxidants that improve mechanical or chemical durability. For example, by adding a filler to the matrix resin 11, the thermal shrinkage rate of the matrix resin 11 can be reduced to approach the thermal shrinkage rate of the superconducting wire 12, and the heat cycle properties of the resin-coated superconducting wire 1 can be improved.

[0019] Furthermore, when matrix resin 11 is a crystalline resin, the melting point of matrix resin 11 is, for example, preferably 290° C. or less, more preferably 280° C. or less, and even more preferably 270° C. or less. When matrix resin 11 is manufactured by hot molding the raw material, the lower the melting point of the raw resin is, the lower the molding temperature can be, and therefore the more likely it is that the performance degradation of superconducting wire 12 caused by heating during molding can be suppressed.

[0020] Suitable examples of the crystalline resin constituting the matrix resin 11 include polyethylene, polypropylene, nylon 11, nylon 12, nylon 6, nylon 66, nylon 610, nylon MXD6, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP), tetrafluoroethylene-ethylene copolymer resin (ETFE), and the like.

[0021] From the viewpoint of further suppressing the performance deterioration of superconducting wire 12 due to heating during molding as described above, the melting point of matrix resin 11 is preferably 210° C. or less, more preferably 200° C. or less, and even more preferably 190° C. or less. Among the above crystalline resins constituting matrix resin 11, polyethylene, polypropylene, nylon 11, and nylon 12 are preferred.

[0022] The matrix resin 11 is preferably nylon or polyolefin, and among these, nylon 11, nylon 12, nylon 6, nylon 66, nylon 610, nylon MXD6, polyethylene, and polypropylene are more preferable, and nylon 11, nylon 12, polyethylene, and polypropylene are even more preferable because they have particularly low melting points, low heat shrinkage rates, excellent water absorption resistance (low water absorption rate), flexibility, and mechanical properties.

[0023] Furthermore, when matrix resin 11 is an amorphous resin, the glass transition point of the synthetic resin material constituting matrix resin 11 is, for example, preferably 250° C. or lower, more preferably 240° C. or lower, and even more preferably 230° C. or lower. For example, when matrix resin 11 is manufactured by hot molding the raw material, the lower the glass transition point of the raw material, the lower the temperature at which resin coating molding can be performed, and therefore the more the performance change of superconducting wire 12 caused by heating during molding can be suppressed.

[0024] The amorphous resin constituting the matrix resin 11 is preferably, for example, polycarbonate, polyphenylene ether, polyetherimide, polyethersulfone, or the like.

[0025] Fig. 3 is a cross-sectional view of another example of a resin-coated superconducting wire (rectangular shape), and Fig. 4 is a cross-sectional view of another example of a resin-coated superconducting wire (circular shape). The resin-coated superconducting wire 1 shown in Figs. 3-4 is a multi-layer coated wire in which a matrix resin 11 composed of multiple matrix resin layers covers the outer periphery of a superconducting wire 12. Specifically, unlike Figs. 1-2, the matrix resin 11 in Figs. 3-4 is composed of an annular inner matrix resin layer 11a that covers the outer periphery of the superconducting wire 12, and one or more outer matrix resin layers 11b that cover the inner matrix resin layer 11a from the outside. Note that Figs. 3-4 show a two-layer structure in which the matrix resin 11 is composed of the inner matrix resin layer 11a and one outer matrix resin layer 11b.

[0026] As shown in Figures 3 and 4, the resin-coated superconducting wire 1 is preferably a multi-layer coated wire having two or more matrix resin layers, such as an inner matrix resin layer 11a and an outer matrix resin layer 11b, and more preferably a multi-layer coated wire having two to four matrix resin layers. By forming the resin-coated superconducting wire 1 into a multi-layer coated wire, the amount of resin used in one extrusion coating can be reduced, and it is expected that the dimensional accuracy of the extrusion coated wire can be improved. Furthermore, by using different resins for each matrix resin layer, the functionality of the resin-coated superconducting wire 1 can be further improved.

[0027] Specifically, in the case of polyolefin resins such as polyethylene and polypropylene that have low adhesion to the superconducting wire 12, the adhesion between the superconducting wire 12 and the outer polyolefin resin 11b can be improved by forming a multi-layered covered wire in which the inner matrix resin layer 11a, which is the first layer on the conductor side, is an olefin-based resin containing at least one functional group selected from the group consisting of an epoxy group, an oxazolyl group, an amino group, and a maleic anhydride residue, or a copolymer thereof (also referred to as copolymer (A)). Also, a similar improvement in adhesion can be expected by forming a multi-layered covered wire in which the inner matrix resin layer 11a is an olefin-based copolymer (also referred to as olefin-based copolymer (B)) containing a metal salt of a carboxylic acid.

[0028] Suitable olefin components constituting the copolymer (A) include ethylene, propylene, butene-1, pentene-1, 4-methylpentene-1, isobutylene, hexene-1, decene-1, octene-1, 1,4-hexadiene, dicyclopentadiene, etc., and among these, preferred are ethylene, propylene, and butene-1. These components may be used alone or in combination of two or more.

[0029] The copolymer component other than the olefin constituting the copolymer (A) may be at least one of an acrylic component and a vinyl component.

[0030] As the acrylic component, acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, etc. are suitable. As the vinyl component, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl chloride, vinyl alcohol, styrene, etc. are suitable. Among them, methyl acrylate and methyl methacrylate are more preferable. These components may be used alone or in combination of two or more. Representative suitable examples of the copolymer (A) include polyethylene or polypropylene grafted with maleic anhydride, and ethylene / glycidyl methacrylate copolymer, etc. As commercially available resins, there are Admer (trade name, manufactured by Mitsui Chemicals), Bondfast (trade name, manufactured by Sumitomo Chemical Co., Ltd.), Rotader (trade name, manufactured by Atofina).

[0031] As the carboxylic acid constituting the olefin copolymer (B), preferably, unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and phthalic acid can be mentioned. As the metal salts thereof, salts of Zn, Na, K, Mg, etc. can be mentioned. As such an olefin copolymer (B), preferably, a part of the carboxylic acid of an ethylene-methacrylic acid copolymer is made into a metal salt, and a resin generally called an ionomer (for example, Himilan; trade name, manufactured by Mitsui Polychemicals Co., Ltd.) can be mentioned.

[0032] As the matrix resin 11, the heat shrinkage rate calculated by the following method is preferably 5% or less, more preferably 2% or less, and even more preferably 1% or less. Thereby, when the matrix resin 11 is immersed in a refrigerant such as liquid helium, damage and deterioration of the matrix resin 11 can be suppressed.

[0033] (Method for calculating the heat shrinkage rate) 0.2 g of resin-coated superconducting wire 1 cut in the longitudinal direction of resin-coated superconducting wire 1 is immersed in 500 mL of liquid helium for several minutes, the dimensions of resin-coated superconducting wire 1 are measured, and the thermal shrinkage rate is calculated by the following formula (1). Thermal shrinkage rate (%) = {(dimension of resin-coated superconducting wire before immersion - dimension of resin-coated superconducting wire after immersion) / dimension of resin-coated superconducting wire before immersion} × 100 Formula (1)

[0034] The water absorption rate of the matrix resin 11 calculated by the following method is preferably 1.0% or less, and more preferably 0.7% or less. The lower the water absorption rate, the less the surface of the matrix resin 11 expands. This makes it possible to suppress damage and deterioration of the matrix resin 11 due to water absorption, and reduction in mechanical strength due to alteration and cracks caused by water absorption of the matrix resin 11. The calculation method shown below is one of the methods for determining the water absorption rate of plastics specified in JIS K7209.

[0035] (Calculation method of water absorption rate) 1.0 g of resin-coated superconducting wire 1 cut out in the longitudinal direction of the resin-coated superconducting wire 1 is immersed in 500 mL of water at 23°C for 24 hours, the water on the surface is then wiped off, the mass of the resin-coated superconducting wire 1 is measured, and the water absorption is calculated by the following formula (2). Water absorption rate (%) = {(mass of resin-coated superconducting wire before immersion - mass of resin-coated superconducting wire after immersion) / mass of resin-coated superconducting wire before immersion} × 100 Equation (2)

[0036] [Superconducting wire] The superconducting wire 12 is a wire extending in the above-mentioned matrix resin 11 and has superconductivity.

[0037] The size of the cross section of superconducting wire 12, for example, if it is circular, is preferably 0.05 to 2.00 mmφ, more preferably 0.07 to 1.50 mmφ, and even more preferably 0.1 to 1.0 mmφ. If the cross section of superconducting wire 12 is rectangular, the long side is preferably 0.8 mm to 2.5 mm, and more preferably 1.5 mm to 2.0 mm, and the short side is preferably 0.5 mm to 1.5 mm, and more preferably 0.9 mm to 1.2 mm.

[0038] The superconducting wire 12 is preferably made of one or more superconducting materials selected from the group consisting of, for example, metal / niobium titanium, metal / niobium tritin, metal / magnesium diboride, rare earth-based and bismuth-based superconducting materials. Note that "metal / niobium titanium", "metal / niobium tritin" and "metal / magnesium diboride" refer to a composite material formed by coating niobium titanium, niobium tritin or magnesium diboride with a metal such as copper or iron.

[0039] Specifically, the rare earth material is YBa 2 Cu 3 O 7-δ , GdBa 2 Cu 3 O 7-δ Bismuth-based materials include Bi 2 Sr 2 Ca 2 Cu 3 O 10+δ , Bi 2 Sr 2 CaCu 2 O 8+δ etc.

[0040] The superconducting wire 12 may be either a single wire or a stranded wire in which a plurality of wires are stranded together.

[0041] [Relationship between matrix resin and superconducting wire] As described above, in the resin-coated superconducting wire 1, the cross-sectional area of ​​the matrix resin 11 is equal to or larger than the cross-sectional area of ​​the superconducting wire 12 when viewed in cross section.

[0042] Also, in the cross section of the resin-coated superconducting wire 1, the ratio of the cross-sectional area of ​​the matrix resin 11 to the cross-sectional area of ​​the superconducting wire 12 (ratio of cross-sectional area of ​​matrix resin 11 / cross-sectional area of ​​superconducting wire 12) is preferably 2 or more, more preferably 5 or more, even more preferably 10 or more, particularly preferably 20 or more, and most preferably 40 or more. The upper limit of the cross-sectional area ratio is preferably 1000 from the practical viewpoint of suitability as a coil material and ease of handling during winding work, for example.

[0043] 1 and 2 show the case where the superconducting wire 12 is located at the center (center of gravity) of the matrix resin 11 when the resin-coated superconducting wire 1 is viewed in cross section, but the superconducting wire 12 may be located at any position in the matrix resin 11 as long as it is not exposed from the surface of the resin-coated superconducting wire 1 (as long as even a small amount of the resin component of the matrix resin 11 is present on the surface of the resin-coated superconducting wire). For example, Figures 5(a) to (f) show modified cross sections of resin-coated superconducting wires 1A to 1F having rectangular cross sections in which superconducting wires 12A to 12F are arranged at different cross-sectional positions of the matrix resins 11A to 11F, respectively.

[0044] In the resin-coated superconducting wire, one superconducting wire 12 is arranged as a single wire or a stranded wire for one matrix resin 11 .

[0045] The cross-sectional shape of the resin-coated superconducting wire may be any shape, such as a circle including an ellipse, a triangle, a square, or a rectangular shape, but a rectangular shape is preferable in terms of ease of forming a coil. When the cross-sectional shape of the resin-coated superconducting wire is a rectangular shape, the cross-sectional shape of the resin-coated superconducting wire also includes those having an R value of 1 mm or less at the corners.

[0046] When the resin-coated superconducting wire has a rectangular shape, the long side of the cross section of the resin-coated superconducting wire is, for example, preferably 0.5 mm to 10 mm, more preferably 1 mm to 7 mm, and the short side of the cross section of the resin-coated superconducting wire is, for example, preferably 0.1 mm to 5 mm, more preferably 0.5 mm to 3 mm.

[0047] The dimensional accuracy of the width and thickness of the resin-coated superconducting wire is preferably ±0.10 mm or less, and more preferably ±0.05 mm or less. Here, "dimensional accuracy" refers to the range of difference between the maximum and minimum dimensions of one resin-coated superconducting wire. By having such dimensional accuracy, the resin-coated superconducting wire can achieve higher electromagnetic shielding performance. To achieve such dimensional accuracy, a method of grinding the outer surface after resin extrusion processing can be used. Another method is to further coat the surface of the above-mentioned matrix resin with, for example, a UV-curable resin material.

[0048] The above-described resin-coated superconducting wire can be applied to superconducting coils, particularly shield coils used in NMR devices, MRI examination devices, and the like.

[0049] The voltage that can be applied to the above-mentioned resin-coated superconducting wire is not particularly limited, but is preferably 0 to 50V, more preferably 0 to 20V, and even more preferably 0 to 10V, for example.

[0050] Furthermore, resin-coated superconducting wires are lighter and less expensive than conventional superconducting wires that contain stabilized copper, and furthermore, they are less likely to develop bending quirks, have improved flexibility, and are also excellent in terms of flexibility, making them easy to handle and wind into coils.

[0051] 2. Manufacturing method of resin-coated superconducting wire The resin-coated superconducting wire of the above embodiment can be manufactured, for example, by inserting a superconducting wire into the synthetic resin raw material constituting the matrix resin and extruding it in the same manner as in the manufacturing method of an extrusion molded body of a normal resin material. The heating temperature, extrusion speed, etc. may be appropriately adjusted depending on the type of synthetic resin raw material, the size and shape of the molded body to be molded, etc.

[0052] In addition, in the conventional technology, a two-step process was carried out in which the superconducting wire, which is a strand, was first resin-coated and then embedded in a copper channel, whereas in the resin-coated superconducting wire of the embodiment, the matrix resin can be molded into the same shape as the copper channel, so the conventional two-step process can be completed in a single process. EXAMPLES

[0053] Next, in order to further clarify the effects of the present disclosure, examples will be described, but the present disclosure is not limited to these examples.

[0054] (Examples 1 to 40) As the raw material of the synthetic resin material, nylon 11 (ARKEMA, BESN Noir TL), nylon 12 (Ube Industries, UBESTA3030LUX), nylon 6 (Ube Industries, UBESTA1024JI), nylon 66 (Asahi Kasei, Leona (registered trademark) 1300S), and high density polyethylene (Asahi Kasei, Suntech (registered trademark)-HD B891) were used, and a copper / niobium titanium superconducting wire of 0.3 mmφ was inserted into the raw material of the synthetic resin material, and extrusion processing was performed under a temperature condition of melting point +20°C or more and melting point +80°C or less using a die having a rectangular shape (Examples 1 to 20) or a round shape (Examples 21 to 40) and the dimensions shown in Tables 2 and 3 below. The superconducting wire was arranged so as to be in the center of the synthetic resin material, as shown in Figures 1 and 2. In Examples 1 to 20, a resin-coated superconducting wire having a rectangular cross-sectional shape was manufactured. In Examples 21 to 40, resin-coated superconducting wires having a circular cross section were produced.

[0055] (Example 41) High density polyethylene (Suntec (registered trademark)-HD B891, manufactured by Asahi Kasei) was used as the raw material for the synthetic resin material, and a 0.3 mmφ copper / niobium titanium superconducting wire coated with a 20 μm-thick layer of modified low density polyethylene graft-copolymerized with maleic anhydride (Admer NB508, manufactured by Mitsui Chemicals) was inserted into the raw synthetic resin material, and extrusion was performed under temperature conditions ranging from the melting point of each resin material +20°C to the melting point +80°C using a rectangular die having the dimensions shown in Table 4 below. The superconducting wire was positioned so that it was in the center of the synthetic resin material, as shown in Figure 3.

[0056] (Example 42) A resin-coated superconducting wire was obtained in the same manner as in Example 41, except that a 0.3 mmφ copper / niobium titanium superconducting wire coated with a 20 μm-thick ethylene-methacrylic acid copolymer (Himilan 1855, manufactured by Mitsui Polychemical) in which some of the carboxylic acid was converted into a metal salt was used.

[0057] (Example 43) High density polyethylene (Suntec (registered trademark)-HD B891, manufactured by Asahi Kasei) was used as the raw material for the synthetic resin material, and a 0.3 mmφ copper / niobium titanium superconducting wire coated with a 20 μm-thick layer of modified low density polyethylene graft-copolymerized with maleic anhydride (Admer NB508, manufactured by Mitsui Chemicals) was inserted into the raw material for the synthetic resin material, and extrusion was performed under temperature conditions ranging from the melting point of each resin material +20°C to the melting point +80°C using a round mold with the dimensions shown in Table 5 below. The superconducting wire was positioned so that it was in the center of the synthetic resin material, as shown in FIG. 4.

[0058] The cross-sectional area of ​​the matrix resin was calculated by determining the cross-sectional area of ​​the outer shape from the outer dimensions of the resin-coated superconducting wire when viewed in cross section of the resin-coated superconducting wire, and calculating the difference between this cross-sectional area and the cross-sectional area of ​​the superconducting wire. From this cross-sectional area of ​​the matrix resin, the mass and cost of the resin per 1000 m of the resin-coated superconducting wire length, as well as their copper equivalents, were calculated. The results are shown in Tables 2 to 5 below. In Tables 2 to 5, the figures in parentheses indicate the copper equivalents for the same volume.

[0059] The melting point, glass transition point, heat shrinkage rate and water absorption rate of each of the synthetic resin materials used in Examples 1 to 43 are shown in Table 1. The heat shrinkage rate and water absorption rate were determined by the method described above.

[0060] [Table 1]

[0061] [Table 2]

[0062] [Table 3]

[0063] [Table 4]

[0064] [Table 5]

[0065] It was confirmed that the resin-coated superconducting wires of Examples 1 to 43 were obtained with dimensions equivalent to those of superconducting wires using conventional copper channels, and thus achieved magnetic shielding characteristics equivalent to those of superconducting wires using conventional copper channels.

[0066] Furthermore, as shown in Tables 2 to 5 above, it was found that the resin-coated superconducting wires of Examples 1 to 43 were able to achieve a significant reduction in mass and raw material costs compared to the copper-coated superconducting wire. [Explanation of symbols]

[0067] 1,1A,1B,1C,1D,1E,1F,2 Resin-coated superconducting wire 11, 11A, 11B, 11C, 11D, 11E, 11F Matrix resin 11a Inner matrix resin layer 11b Outer matrix resin layer 12,12A,12B,12C,12D,12E,12F,22 Superconducting wire 21 Stabilized Copper

Claims

1. a matrix resin made of a synthetic resin material; a superconducting wire extending in the matrix resin; A resin-coated superconducting wire having the matrix resin constitutes the outermost surface of the resin-coated superconducting wire, the superconducting wire is one, A resin-coated superconducting wire, characterized in that the cross-sectional area of ​​the matrix resin is equal to or greater than the cross-sectional area of ​​the superconducting wire when viewed in cross section of the resin-coated superconducting wire.

2. A resin-coated superconducting wire as described in claim 1, characterized in that the superconducting wire is made of one or more materials selected from the group consisting of metal / niobium titanium, metal / niobium tritin, metal / magnesium diboride, rare earth-based and bismuth-based superconducting materials.

3. A resin-coated superconducting wire as described in claim 1 or 2, characterized in that the synthetic resin material is a thermoplastic resin.

4. A resin-coated superconducting wire as described in claim 3, characterized in that the melting point of the thermoplastic resin is 290°C or less.

5. A resin-coated superconducting wire as described in claim 3 or 4, characterized in that the melting point of the thermoplastic resin is 210°C or less.

6. A resin-coated superconducting wire described in any one of claims 1 to 5, characterized in that the synthetic resin material is polyamide or polyolefin.

7. A resin-coated superconducting wire as described in claim 6, characterized in that the polyamide is nylon.

8. A resin-coated superconducting wire described in any one of claims 1 to 7, characterized in that the synthetic resin material is nylon 11, nylon 12 or polyethylene.

9. A resin-coated superconducting wire described in any one of claims 1 to 5, characterized in that the synthetic resin material is an amorphous resin having a glass transition point of 250°C or less.

10. A resin-coated superconducting wire according to any one of claims 1 to 9, characterized in that the resin-coated superconducting wire is a multi-layer coated wire composed of two or more matrix resin layers, each of which is composed of an inner matrix resin layer covering the outer periphery of the superconducting wire and one or more outer matrix resin layers covering the outside of the inner matrix resin layer.

11. A resin-coated superconducting wire as described in claim 10, characterized in that the inner matrix resin layer is an olefin-based resin or a copolymer thereof containing at least one functional group selected from the group consisting of an epoxy group, an oxazolyl group, an amino group, and a maleic anhydride residue.

12. A resin-coated superconducting wire as described in claim 10, characterized in that the inner matrix resin layer is an olefin-based copolymer containing a metal salt of a carboxylic acid.

13. A resin-coated superconducting wire according to any one of claims 1 to 12, characterized in that the superconducting wire is a single wire.

14. A resin-coated superconducting wire according to any one of claims 1 to 12, characterized in that the superconducting wire is a twisted wire.

15. A resin-coated superconducting wire described in any one of claims 1 to 14, characterized in that the cross-sectional shape of the resin-coated superconducting wire is a rectangular shape.

16. A resin-coated superconducting wire described in any one of claims 1 to 14, characterized in that the cross-sectional shape of the resin-coated superconducting wire is circular.

17. A resin-coated superconducting wire described in any one of claims 1 to 16, characterized in that the dimensional accuracy of the width and thickness of the resin-coated superconducting wire is ±0.10 mm or less.

18. A resin-coated superconducting wire described in any one of claims 1 to 17, characterized in that the dimensional accuracy of the width and thickness of the resin-coated superconducting wire is ±0.05 mm or less.

19. A resin-coated superconducting wire according to any one of claims 1 to 18, used in a shield coil.

20. A superconducting coil using a resin-coated superconducting wire described in any one of claims 1 to 18.

21. A shielded coil using a resin-coated superconducting wire described in any one of claims 1 to 19.

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