HK1200591B - Insulated wire and electrical/electronic device - Google Patents

Abstract

The present invention relates to insulated wires and electrical/electronic devices using insulated wires as winding wires and/or leads for transformers installed in electrical/electronic equipment,The insulated wire has two or more layers of insulation covering the conductor,The innermost insulation layer of a multi-layer insulation layer is formed by a crystalline thermoplastic resin with a storage modulus of 10 MPa or more at 300 ℃,The outer insulation layer outside the innermost insulation layer includes an insulation layer formed of a crystalline thermoplastic resin with a melting point of 260 ℃ or higher and a storage modulus of 1000MPa or higher at 25 ℃,The adjacent insulation layers are in the following relationship: the storage modulus of the thermoplastic resin in the outer insulation layer at 25 ℃ is equal to or less than the storage modulus of the thermoplastic resin in the inner insulation layer at 25 ℃.

Description

Insulated wire and electric/electronic device

Technical Field

The present invention relates to an insulated wire and an electric/electronic device, and more particularly, to an insulated wire having excellent physical properties such as heat resistance and useful as a winding wire and/or a lead wire of a transformer to be mounted in an electric/electronic device or the like, and an electric/electronic device such as a transformer using the insulated wire.

Background

The structure of the transformer is defined by IEC standard (International Electrotechnical commission standard) publications 950, 65, 335, 601 and the like. Namely, these standards specify: 1) the enamel coating film of the coated conductor in the winding wire is not considered as an insulating layer, and at least 3 insulating layers including auxiliary insulation are formed between the primary winding wire and the secondary winding wire; or 2) the insulating layer has a thickness of 0.4mm or more, and for example, the creepage distance between the primary winding wire and the secondary winding wire differs depending on the applied voltage, but is 5mm or more; 3) furthermore, the primary side and the secondary side can bear more than 1 minute when 3000V is applied; and so on.

Therefore, a cross-sectional structure as shown in fig. 3 has been adopted in mainstream transformers so far. Namely the following structure: the flanged winding bobbin 2 is inserted into the ferrite core 1, the primary winding wire 4 coated with enamel is wound in a state where the insulation barriers 3 for securing a creepage distance are arranged at both peripheral end sides of the winding bobbin 2, then at least 3 layers of the insulation tapes 5 are wound on the primary winding wire 4, and further the insulation barriers 3 for securing a creepage distance are arranged on the insulation tapes 5, and then the secondary winding wire 6 coated with enamel is similarly wound.

However, in recent years, transformers having a structure without the insulating barrier 3 and the insulating tape layer 5 shown in fig. 2 have begun to appear instead of the transformers having the cross-sectional structure shown in fig. 3. This transformer has advantages that the whole can be made smaller and the winding work of the insulating tape 5 can be omitted, as compared with the transformer shown in fig. 3.

In manufacturing the transformer shown in fig. 2, IEC standards require that 3 insulating layers 4b, 4c, and 4d or 6b, 6c, and 6d be formed on the outer periphery of the conductor 4a or 6a of either or both of the primary winding wire 4 and the secondary winding wire 6 to be used. In addition, according to the IEC standard, it is also required that the primary winding wire 4 and the secondary winding wire 6 can be mutually laminated between the insulating layers.

As such a winding wire, the following winding wires are known: an insulating tape is wound around the outer periphery of the conductor to form a 1 st insulating layer, and an insulating tape is wound around the 1 st insulating layer to form a 2 nd insulating layer and a 3 rd insulating layer in this order, thereby forming 3-layer insulating layers in which the number of insulating layers between layers can be confirmed. Further, the following winding wire is also known: a fluororesin is sequentially extrusion-coated on the outer periphery of a polyurethane enamel-coated conductor, and the entire extrusion-coated layer having a 3-layer structure is used as an insulating layer (see, for example, patent document 1).

As an insulated wire having a plurality of insulating layers, for example, a multilayer insulated wire having a conductor and 3 or more extruded insulating layers covering the conductor is proposed, in which an innermost layer (B) of the insulating layers is formed of an extruded coating layer containing a resin obtained by impregnating a thermoplastic linear polyester resin having an elongation in a specific range in a solder bath at 150 ℃ for 2 seconds and an ethylene copolymer or an epoxy group-containing resin (patent document 2).

Further, "a multilayer insulated wire having 2 or more insulating layers on a conductor, wherein the outermost layer of the insulating layer is composed of an extruded coating layer of a polyamide resin and the other layer is composed of an extruded coating layer of polyethersulfone" (patent document 3).

Documents of the prior art

Patent document

Patent document 1: japanese Kokai publication Hei-3-56113

Patent document 2: japanese patent No. 4579989

Patent document 3: japanese laid-open patent publication No. 10-134642

Disclosure of Invention

Problems to be solved by the invention

However, recently, there has been a high demand for downsizing transformers, and there has been a problem that the heat generation amount of transformers increases due to downsizing, and there has been a large demand that cannot be met by the class B heat resistance (heat resistance index 130 ℃) of the above-mentioned 3-layer insulated wire. In order to meet such a demand, it is necessary to develop a heat-resistant insulated wire having a heat resistance class F (heat resistance index 155 ℃) by further improving the heat resistance.

In addition, the insulated wire is required to have excellent scratch resistance and strong deformation resistance so as to be able to withstand an impact at the time of coil molding, in addition to the insulating layer being tightly adhered and not easily peeled off.

Furthermore, insulated wires are also used for electric/electronic devices that generate heat, such as motors; or an electric/electronic device disposed in a use environment where the ambient temperature rises and falls. Therefore, the insulated wire, particularly the insulated wire used in the electric/electronic equipment or the use environment, is also required to have "flexibility before and after heating" which maintains the flexibility originally possessed even when repeatedly heated.

The invention provides an insulated wire having at least two insulating layers, which satisfies the requirement of improving heat resistance and has the necessary characteristics such as heat shock resistance, flexibility before and after heating, and scratch resistance required by coil application.

Further, another object of the present invention is to provide an electric/electronic device such as a transformer, which is obtained by winding an insulated wire having the above-described required characteristics, and which has high reliability such that the insulation property is maintained even under severe processing conditions and use environments.

Means for solving the problems

The above object of the present invention is achieved by an insulated wire and a transformer using the insulated wire described below.

(1) An insulated wire having two or more insulating layers covering a conductor, wherein an innermost insulating layer of the insulating layers is an insulating layer made of a crystalline thermoplastic resin having a storage modulus at 300 ℃ of 10MPa or more, and outer insulating layers other than the innermost insulating layer include insulating layers made of a crystalline thermoplastic resin having a melting point of 260 ℃ or more and a storage modulus at 25 ℃ of 1000MPa or more, and adjacent insulating layers are in the following relationship: the storage modulus at 25 ℃ of the thermoplastic resin of the insulating layer located on the outer side is equal to or smaller than the storage modulus at 25 ℃ of the thermoplastic resin of the insulating layer located on the inner side.

(2) The insulated wire according to the item (1), wherein the innermost insulating layer is an insulating layer formed of at least one thermoplastic resin selected from the group consisting of a polyether ether ketone resin, a modified polyether ether ketone resin, and a thermoplastic polyimide resin.

(3) The insulated wire according to (1) or (2), wherein at least one of the outermost insulating layers of the plurality of insulating layers is an insulating layer made of a polyamide resin.

(4) The insulated wire according to any one of (1) to (3), wherein the innermost insulating layer is an insulating layer made of a polyether ether ketone resin or a modified polyether ether ketone resin, and at least one of the outermost insulating layers is an insulating layer made of polyamide 66.

(5) An electric/electronic device characterized by using the insulated electric wire of any one of (1) to (4) as a winding wire and/or a lead wire of a transformer mounted in the electric/electronic device.

In the present invention, the number of layers of the multilayer insulating layer is determined based on the interlayer interface when the cross section of the insulated wire is observed with a microscope.

The above features and advantages and other features and advantages of the present invention are readily apparent from the following description when taken in connection with the accompanying drawings.

Effects of the invention

The insulated wire of the present invention is excellent in thermal shock resistance, flexibility before and after heating, and scratch resistance required for coil applications, in addition to sufficiently satisfying the heat resistance level. Therefore, according to the present invention, an insulated wire having excellent thermal shock resistance, flexibility before and after heating, and scratch resistance while maintaining heat resistance of class F or higher can be provided. Further, the electric/electronic equipment such as a transformer using the insulated wire of the present invention having the above-described characteristics maintains insulation even under severe processing conditions and use environments, and exhibits high reliability.

Drawings

Fig. 1(a) is a sectional view showing one example of an insulated electric wire of the present invention, and fig. 1(b) is a sectional view showing another example of an insulated electric wire of the present invention.

Fig. 2 is a sectional view showing an example of a transformer having a structure in which 3-layer insulated electric wires are used as winding wires.

Fig. 3 is a sectional view showing an example of a transformer of a conventional structure.

Detailed Description

The present invention is an insulated wire having two or more insulating layers covering a conductor, wherein an innermost insulating layer of the insulating layers is an insulating layer formed of a crystalline thermoplastic resin having a storage modulus at 300 ℃ of 10MPa or more, an outer insulating layer other than the innermost insulating layer includes an insulating layer formed of a crystalline thermoplastic resin having a melting point of 260 ℃ or more and a storage modulus at 25 ℃ of 1000MPa or more, and adjacent two insulating layers are in the following relationship: the storage modulus at 25 ℃ of the thermoplastic resin of the insulating layer located on the outer side is equal to or smaller than the storage modulus at 25 ℃ of the thermoplastic resin of the insulating layer located on the inner side.

The storage modulus of the thermoplastic resin forming each insulating layer of the insulated wire of the present invention is a value measured using a viscoelasticity analyzer (manufactured by Seiko Instruments: DMS200 (trade name)). Specifically, using a test piece having a thickness of 0.2mm made of a thermoplastic resin forming each insulation layer of the insulated wire, the values of the storage modulus at 25 ℃ and 300 ℃ were recorded under the conditions of a temperature rise rate of 2 ℃/min and a frequency of 10Hz, and the recorded values were taken as the storage modulus of the thermoplastic resin at 25 ℃ or 300 ℃.

The melting point of the thermoplastic resin can be measured by Differential Scanning Calorimetry (DSC), for example. Specifically, the melting point was determined by reading the peak temperature of the heat due to melting observed in a region exceeding 250 ℃ when the temperature of 10mg of the sample was raised at a rate of 5 ℃/min using a thermal analyzer "DSC-60" (manufactured by Shimadzu corporation). When there are two or more peak temperatures, the melting point is defined as the peak temperature higher in temperature.

The insulated wire of the present invention includes two or more layers of insulating layers as insulating layers for covering a conductor. In the present invention, the insulating layers constituting the multilayer insulating layer are at least two layers, and particularly preferably three layers. In the present invention, among the plurality of insulating layers, the insulating layer which is close to the conductor and covers the conductor is referred to as an innermost insulating layer, the insulating layers other than the innermost insulating layer are referred to as outer insulating layers, and the outermost insulating layer from the conductor among the outer insulating layers is referred to as an outermost insulating layer.

The structure of a preferred embodiment of the insulated wire of the present invention will be described.

As one embodiment, an insulated wire 10 having 2 insulating layers shown in fig. 1(a) can be given. As shown in fig. 1(a), this insulated wire 10 has a conductor 11, an innermost insulating layer 12 covering the conductor 11, and an outermost insulating layer 13 covering the innermost insulating layer 12. In this insulated wire 10, the outermost insulation layer 13 is also an outer insulation layer.

In another embodiment, an insulated wire 20 having 3 insulating layers as shown in fig. 1(b) is exemplified. As shown in fig. 1(b), this insulated wire 20 has a conductor 21, an innermost insulating layer 22 covering the conductor 21, an intermediate insulating layer 23 covering the innermost insulating layer 22, and an outermost insulating layer 24 covering the intermediate insulating layer 23. In this insulated wire 20, the intermediate insulating layer 23 and the outermost insulating layer 24 form an outer insulating layer.

The scope of the present invention is not limited to these embodiments, and various modifications can be made within the scope not impairing the spirit of the present invention. For example, the innermost insulating layer 12 or 22 may be directly covered with the conductor 11 or 21 as shown in fig. 1, or may be covered with another layer interposed therebetween.

As the conductor 11, a bare metal wire (single wire), a multi-core stranded wire obtained by stranding two or more bare metal wires, or the like can be used. The number of strands of these strands can be selected at will according to the high frequency application. In addition, when the number of the bare metal wires is large, the bare metal wires may not be stranded wires. When the metal wires are not stranded wires, for example, only two or more metal bare wires may be bundled in parallel, or the metal bare wires may be stranded at a very large pitch after bundling. In either case, it is preferred that the conductor 11 be substantially circular in cross-section. The metal forming the conductor 11 is not particularly limited, and examples thereof include copper and copper alloys.

The innermost insulating layer 12 or 22 of the multilayer insulating layers is a coating layer formed of a crystalline thermoplastic resin. When the innermost insulating layer 12 or 22 is formed of a crystalline thermoplastic resin, the insulated wire exhibits high heat resistance. The innermost insulating layer 12 or 22 is a coating layer made of a thermoplastic resin having a storage modulus at 300 ℃ of 10MPa or more. If the storage modulus is less than 10MPa, the heat resistance required for the insulated wire cannot be obtained, and therefore, the innermost insulating layer 12 or 22 is not suitable. The storage modulus of the thermoplastic resin forming the innermost insulating layer 12 or 22 is preferably 50MPa or more. The upper limit of the storage modulus is not particularly limited, but is practically 500MPa, preferably 200 MPa.

The thermoplastic resin forming the innermost insulating layer 12 or 22 is not particularly limited as long as the storage modulus at 300 ℃ is within the above range. For example, the storage modulus of the thermoplastic resin at 25 ℃ is not particularly limited, and may be 1500 to 6000MPa, and further 1800 to 4000MPa, as an example of the storage modulus. The melting point of the thermoplastic resin forming the innermost insulating layer 12 or 22 is not particularly limited, and may be 310 to 400 ℃, and further may be 340 to 390 ℃, taking as an example the melting point. When the storage modulus and the melting point of the thermoplastic resin at 25 ℃ are within the above ranges, the insulated wire exhibits high heat resistance.

The thermoplastic resin forming the innermost insulating layer 12 or 22 may be a crystalline thermoplastic resin having a storage modulus at 300 ℃ of 10MPa or more, and is appropriately selected in consideration of the storage modulus and crystallinity at 300 ℃. Examples of such thermoplastic resins include polyether ether ketone resins (hereinafter referred to as PEEK), modified polyether ether ketone resins (hereinafter referred to as modified PEEK), and thermoplastic polyimide resins (hereinafter referred to as thermoplastic PI). In the invention, the thermoplastic resin is preferably at least one thermoplastic resin selected from the group consisting of a PEEK resin, a modified PEEK resin, and a thermoplastic PI resin. Among crystalline thermoplastic resins having a storage modulus of 10MPa or more at 300 ℃, PEEK, modified PEEK, and thermoplastic polyimide are particularly excellent in heat aging resistance. Among them, a PEEK resin and a modified PEEK resin are more preferable. These resins are excellent in heat aging resistance and also in scratch resistance because they have a high storage modulus at room temperature.

Examples of the thermoplastic polyimide resin include aromatic thermoplastic polyimides and aliphatic thermoplastic polyimides. These thermoplastic polyimides are obtained by reacting an acid component with a diamine component or a diisocyanate component.

Examples of the acid component of the thermoplastic polyimide resin include pyromellitic dianhydride, 3,3',4,4' -benzophenonetetracarboxylic dianhydride, 2,3,3',4' -benzophenonetetracarboxylic dianhydride, 2',3,3' -benzophenonetetracarboxylic dianhydride, 3,3',4,4' -biphenyltetracarboxylic dianhydride, 2',3,3' -biphenyltetracarboxylic dianhydride, 2-bis (2, 3-dicarboxyphenyl) propane dianhydride, bis (3, 4-dicarboxyphenyl) ether dianhydride, bis (3, 4-dicarboxyphenyl) sulfone dianhydride, 1-bis (2, 3-dicarboxyphenyl) ethane dianhydride, bis (2, 3-dicarboxyphenyl) methane dianhydride, bis (3, 4-dicarboxyphenyl) methane dianhydride, 2,2 '-bis (3, 4-dicarboxyphenyl) -1,1,1,3,3, 3-hexafluoropropane dianhydride, 1, 4-difluoropyromellitic acid, 1, 4-bis (trifluoromethyl) pyromellitic acid, 1, 4-bis (3, 4-dicarboxytrifluorophenoxy) tetrafluorobenzene dianhydride, 2' -bis [4- (3, 4-dicarboxyphenoxy) benzene ] -1,1,1,3,3, 3-hexafluoropropane dianhydride, 2,3,6, 7-naphthalenetetracarboxylic dianhydride, 1,4,5, 8-naphthalenetetracarboxylic dianhydride, 1,2,5, 6-naphthalenetetracarboxylic dianhydride, 1,2,3, 4-benzenetetracarboxylic dianhydride, 3,4,9, 10-perylenetetracarboxylic dianhydride, 2,3,6, 7-anthracenetetracarboxylic dianhydride, 1,2,7, 8-phenanthrene tetracarboxylic dianhydride, 1,2,3, 4-butanetetracarboxylic dianhydride, 1,2,3, 4-cyclobutanetetracarboxylic dianhydride, and the like, and further, there may be mentioned various components such as a hydrolysis ring-opened product obtained by opening at least a part of these by hydrolysis.

Examples of the diamine component or diisocyanate component of the polyimide resin include 4,4 '-bis (3-aminophenoxy) biphenyl, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 4' -diaminodiphenyl ether, 3 '-diaminodiphenyl ether, 3,4' -diaminodiphenyl ether, bis (3-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, (3-aminophenyl) (4-aminophenyl) sulfide, bis (3-aminophenyl) sulfoxide, bis (4-aminophenyl) sulfoxide, (3-aminophenyl) (4-aminophenyl) sulfoxide, bis (3-aminophenyl) sulfone, bis (4-aminophenyl) sulfone, (3-aminophenyl) (4-aminophenyl) sulfone, bis (3-aminophenyl) sulfone, and mixtures thereof, 3,3' -diaminobenzophenone, 4' -diaminobenzophenone, 3' -diaminodiphenylmethane, 4' -diaminodiphenylmethane, 3,4' -diaminodiphenylmethane, bis [4- (3-aminophenoxy) phenyl ] methane, bis [4- (4-aminophenoxy) phenyl ] methane, 1-bis [4- (3-aminophenoxy) phenyl ] ethane, 1, 2-bis [4- (3-aminophenoxy) phenyl ] ethane, 1-bis [4- (4-aminophenoxy) phenyl ] ethane, 1, 2-bis [4- (4-aminophenoxy) phenyl ] ethane, 2-bis [4- (3-aminophenoxy) phenyl ] propane, 2, 4' -diaminobenzophenone, 3,4' -diaminodiphenylmethane, 4' -diaminodiphenylmethane, 3,4' -diaminodiphenylmethane, 1, 2-bis [4- (3-aminophenoxy) phenyl ] ethane, 1, 2-bis [4, 2, 2-bis [4- (4-aminophenoxy) phenyl ] propane, 2-bis [4- (3-aminophenoxy) phenyl ] butane, 2-bis [3- (3-aminophenoxy) phenyl ] -1,1,1,3,3, 3-hexafluoropropane, 2-bis [4- (4-aminophenoxy) phenyl ] -1,1,1,3,3, 3-hexafluoropropane, 1, 3-bis (3-aminophenoxy) benzene, 1, 3-bis (4-aminophenoxy) benzene, 1, 4-bis (3-aminophenoxy) benzene, 1, 4-bis (4-aminophenoxy) benzene, 4' -bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl ] one, a salt thereof, a crystalline solid, or a crystalline solid, Bis [4- (4-aminophenoxy) phenyl ] ketone, bis [4- (3-aminophenoxy) phenyl ] sulfide, bis [4- (4-aminophenoxy) phenyl ] sulfide, bis [4- (3-aminophenoxy) phenyl ] sulfoxide, bis [4- (4-aminophenoxy) phenyl ] sulfoxide, bis [4- (3-aminophenoxy) phenyl ] sulfone, bis [4- (4-aminophenoxy) phenyl ] sulfone, bis [4- (3-aminophenoxy) phenyl ] ether, bis [4- (4-aminophenoxy) phenyl ] ether, 1, 4-bis [4- (3-aminophenoxy) benzoyl ] benzene, 1, 3-bis [4- (3-aminophenoxy) benzoyl ] benzene, bis [4- (3-aminophenoxy) phenyl ] sulfoxide, bis [4- (4-aminophenoxy) phenyl ] sulfone, bis, 4,4 '-bis [3- (4-aminophenoxy) benzoyl ] diphenyl ether, 4' -bis [3- (3-aminophenoxy) benzoyl ] diphenyl ether, 4 '-bis [4- (4-amino- α, α -dimethylbenzyl) phenoxy ] benzophenone, 4' -bis [4- (4-amino- α, α -dimethylbenzyl) phenoxy ] diphenylsulfone, bis [4- {4- (4-aminophenoxy) phenoxy } phenyl ] sulfone, 1, 4-bis [4- (4-aminophenoxy) phenoxy- α, α -dimethylbenzyl ] benzene, 1, 3-bis [4- (4-aminophenoxy) phenoxy- α, alpha-dimethylbenzyl benzene, 1, 3-bis [4- (4-amino-6-trifluoromethylphenoxy) -alpha, alpha-dimethylbenzyl ] benzene, 1, 3-bis [4- (4-amino-6-fluorophenoxy) -alpha, alpha-dimethylbenzyl ] benzene, 1, 3-bis [4- (4-amino-6-methylphenoxy) -alpha, alpha-dimethylbenzyl ] benzene, 1, 3-bis [4- (4-amino-6-cyanophenoxy) -alpha, alpha-dimethylbenzyl ] benzene, 3 '-diamino-4, 4' -diphenoxybenzophenone, 4 '-diamino-5, 5' -diphenoxybenzophenone, alpha-dimethylbenzyl, 3,4 '-diamino-4, 5' -diphenoxybenzophenone, 3 '-diamino-4-phenoxybenzophenone, 4' -diamino-5-phenoxybenzophenone, 3,4 '-diamino-4-phenoxybenzophenone, 3,4' -diamino-5 '-phenoxybenzophenone, 3' -diamino-4, 4 '-phenoxybenzophenone, 4' -diamino-5, 5 '-phenoxybenzophenone, 3,4' -diamino-4, 5 '-diphenoxybenzophenone, 3' -diamino-4, 5 '-phenoxybenzophenone, 3' -diamino-4-phenoxybenzophenone, 4 '-diamino-5-benzoxybenzophenone, 3,4' -diamino-5-phenoxybenzophenone, mixtures thereof, and mixtures thereof, 3,4' -diamino-4-diphenoxybenzophenone, 3,4' -diamino-5 ' -diphenoxybenzophenone, 1, 3-bis (3-amino-4-phenoxybenzoyl) benzene, 1, 4-bis (3-amino-4-phenoxybenzoyl) benzene, 1, 3-bis (4-amino-5-phenoxybenzoyl) benzene, 1, 4-bis (4-amino-5-phenoxybenzoyl) benzene, 1, 3-bis (3-amino-4-diphenoxybenzoyl) benzene, 1, 4-bis (3-amino-4-diphenoxybenzoyl) benzene, 1, 3-bis (4-amino-5-diphenoxybenzoyl) benzene, 1, 4-bis (4-amino-5-diphenoxybenzoyl) benzene, 2, 6-bis [4- (4-amino- α, α -dimethylbenzyl) phenoxy ] benzonitrile, 6 '-bis (2-aminophenoxy) -3,3,3',3 '-tetramethyl-1, 1' -spirobiindan, 6 '-bis (3-aminophenoxy) -3,3,3',3 '-tetramethyl-1, 1' -spirobiindan, and the like, and diisocyanates having an isocyanate group in place of the amino group in them.

The innermost insulating layer 12 or 22 is preferably formed by extrusion molding of the conductor 11 or 21 together with the thermoplastic resin. The innermost insulating layer 12 or 22 may be formed by extrusion molding of a resin composition in which various additives are mixed with these thermoplastic resins. The various additives to be mixed at this time include, but are not particularly limited to, additives that are generally added to thermoplastic resin compositions.

The outer insulating layer other than the innermost insulating layer 12 or 22 is a coating layer made of a crystalline thermoplastic resin. When the outer insulating layer is formed of a crystalline thermoplastic resin, the insulated wire exhibits high heat resistance. The outermost insulating layer 13 of the insulated wire 10, which is the outer insulating layer, and the intermediate insulating layer 23 and the outermost insulating layer 24 of the insulated wire 20 are both coating layers formed of a thermoplastic resin having a melting point of 260 ℃ or higher and a storage modulus of 1000MPa or higher at 25 ℃. When the melting point of the thermoplastic resin is less than 260 ℃, the thermoplastic resin is not suitable as an outer insulating layer because heat resistance required for an insulated wire cannot be obtained or the flexibility of the insulated wire is further reduced by melting of the insulating layer. The melting point of the thermoplastic resin is preferably 270 ℃ or higher. Although not particularly limited, the melting point is preferably 390 ℃ or lower in practical use, more preferably equal to or lower than the melting point of the thermoplastic resin forming the innermost insulating layer 12 or 22, and for example, preferably 350 ℃ or lower.

When the storage modulus of the thermoplastic resin is less than 1000MPa, the heat resistance and scratch resistance required for the insulated wire cannot be obtained, and therefore, the thermoplastic resin is not suitable as an outer insulating layer. The storage modulus of the thermoplastic resin is preferably 1500MPa or more in order to make the insulated wire exhibit higher scratch resistance. The storage modulus is not particularly limited, and practically 5000MPa or less, preferably 4000MPa or less.

Here, it is preferable that the thermoplastic resin forming the outermost insulating layer does not contain the thermoplastic resin forming the innermost insulating layer, and the outermost insulating layer and the innermost insulating layer are each formed of a thermoplastic resin having a different storage modulus at 25 ℃. As for the other layers constituting the multi-layer insulating layer, the insulating layer located on the outer side may be formed using a thermoplastic resin having a storage modulus equal to or smaller than that of the other layers.

The insulated wire of the invention is in the following relationship between adjacent insulation layers including the innermost insulation layer: the storage modulus at 25 ℃ of the thermoplastic resin of the insulating layer located on the outer side is equal to or smaller than the storage modulus at 25 ℃ of the thermoplastic resin of the insulating layer located on the inner side.

In the insulated electric wires 10 and 20, the outer insulating layer is formed of a thermoplastic resin having a storage modulus at 25 ℃ of a value smaller than that of the thermoplastic resin forming the innermost insulating layer 12 or 22. In this way, when the outer insulating layer is formed of a thermoplastic resin having a storage modulus smaller than that of the innermost insulating layer 12 or 22, an insulated wire having high interlayer adhesiveness, being difficult to peel, and having excellent flexibility before and after heating can be obtained. The difference between the storage modulus of the innermost insulating layer 12 or 22 and the storage modulus of the outer insulating layer when the storage modulus is different is not particularly limited, and may be, for example, 500 to 5000 MPa.

In the insulated wire 20, the storage modulus also has the same relationship between the intermediate insulating layer 23 and the outermost insulating layer 24. That is, the two adjacent intermediate insulating layers 23 and outermost insulating layers 24 are in the following relationship: the storage modulus at 25 ℃ of the thermoplastic resin of the outermost insulation layer 24 is equal to or smaller than the storage modulus at 25 ℃ of the intermediate insulation layer 23. When the above relationship is established between two adjacent outer insulating layers, an insulated wire having high interlayer adhesiveness, being difficult to peel, and excellent flexibility before and after heating can be obtained. Thus, the insulated wire of the present invention has high interlayer adhesiveness, is difficult to peel, and has excellent flexibility before and after heating. This interlayer adhesiveness also affects the resistance to damage of the electric wire. The difference in storage modulus between the thermoplastic resins forming the two outer insulating layers adjacent to each other inside and outside is not particularly limited, and may be, for example, 0 to 2000 MPa.

As such, the insulated electric wire 10 and the insulated electric wire 20 as the preferred embodiment of the present invention, the adjacent two layers of insulation including the innermost insulation layers 12 and 22 are in the following relationship: the storage modulus at 25 ℃ of the thermoplastic resin of the insulating layer located on the outer side is equal to or smaller than the storage modulus at 25 ℃ of the thermoplastic resin of the insulating layer located on the inner side. In addition, the innermost insulating layers 12 and 22 and the outermost insulating layers 13 and 24 are in the following relationship: the storage modulus at 25 ℃ of the outermost insulating layers 13 and 24 is smaller than that at 25 ℃ of the thermoplastic resin of the innermost insulating layers 12 and 22.

By satisfying such a relationship with respect to the storage modulus at 25 ℃, the thermal shock resistance, flexibility before and after heating, and scratch resistance are exerted in a well-balanced manner at a higher level.

The thermoplastic resin forming the outer insulating layers 13, 23, and 24 may be any crystalline thermoplastic resin having a melting point of 260 ℃ or higher and a storage modulus at 25 ℃ of 1000MPa or higher. Such a thermoplastic resin may be appropriately selected in consideration of a melting point, a storage modulus at 25 ℃, crystallinity, and the like. Examples of such thermoplastic resins include PEEK resins, modified PEEK resins, thermoplastic PI resins, polyphenylene sulfide resins (hereinafter, referred to as PPS), syndiotactic polystyrene resins (hereinafter, referred to as SPS), and polyamide resins (hereinafter, referred to as PA). The thermoplastic polyimide resin is as described above. Examples of PA include polyamide 66, polyamide 46, polyamide 6T, polyamide 9T, and polyphthalamide. The thermoplastic resin is preferably at least 1 selected from the group consisting of PPS, SPS, and PA, more preferably PA, and particularly preferably polyamide 66 (also referred to as PA 66).

The thermoplastic resin forming the innermost insulating layers 12 and 22 and the outer insulating layers 13, 23 and 24 may also be a commercially available resin. Examples thereof include PEEK450G (trade name, storage modulus at 25 ℃ C.: 3840MPa, storage modulus at 300 ℃ C.: 187MPa, melting point: 345 ℃ C.) manufactured by Victrex Japan as PEEK, AvaScripte AV-650 (trade name, storage modulus at 25 ℃ C.: 3700MPa, storage modulus at 300 ℃ C.: 144MPa, melting point: 340 ℃ C.) manufactured by Solvay as modified PEEK, or AV-651 (trade name, storage modulus at 25 ℃ C.: 3500MPa, storage modulus at 300 ℃ C.: 130MPa, melting point: 345 ℃ C.) manufactured by Sanjing chemical as thermoplastic PI, AURUM PL450C (trade name, storage modulus at 25 ℃ C.: 1880MPa, storage modulus at 300 ℃ C.: 18.9MPa, melting point: 388 ℃ C.), FORTN 0220A9 (PPS, storage modulus at 25 ℃ C.: 2800MPa, storage modulus at 300 ℃ C.: 10MPa, storage modulus at 2100 ℃ C.: 278 ℃ C.) manufactured by Polyplastic corporation as PPS, or FRTN 0220A9 (PPS), storage modulus at 25 ℃: 1600MPa, storage modulus at 300 ℃: < 10MPa, melting point: 275 c), XAREC S105 manufactured by mitsunken corporation as SPS (trade name, storage modulus at 25 c: 2200MPa, melting point: 280 c), polyamide 66FDK-1 manufactured by Unitika corporation as PA (trade name, storage modulus at 25 c: 1200MPa, storage modulus at 300 ℃: < 10MPa, melting point: 265 deg.c), polyamide 46F-5000 (trade name, storage modulus at 25 deg.c: 1100MPa, melting point: 292 deg.c), polyamide 6T ARLEN AE-420 (trade name, storage modulus at 25 deg.c: 2400MPa, melting point: 320 c), polyamide 9T GENESTAR N1006D manufactured by Kuraray corporation (trade name, storage modulus at 25 c: 1400MPa, melting point: 262 ℃ C.), and the like.

The outer insulating layers 13, 23, and 24 are preferably formed by extrusion molding the thermoplastic resin together with the conductor 11 or 21 having the innermost insulating layer 11 or 21 formed thereon, respectively. The outer insulating layers 13, 23, and 24 may be formed by extrusion molding of a resin composition in which various additives are mixed with a thermoplastic resin. The various additives mixed at this time are as described above.

Note that, as long as the multilayer insulating layer has the innermost insulating layers 12 and 22 and the outer insulating layers 13, 23, and 24, it may also have insulating layers that do not belong to these layers, that is, insulating layers formed of a thermoplastic resin other than the thermoplastic resin forming the innermost insulating layers 12 and 22 and the outer insulating layers 13, 23, and 24. The melting point of the thermoplastic resin forming the insulating layer is preferably 250 ℃ or higher.

The insulated wire of the present invention is manufactured by extrusion-coating a 1 st insulating layer (i.e., an innermost insulating layer) having a desired thickness on the outer periphery of a conductor by a conventional method, then extrusion-coating a 2 nd layer having a desired thickness on the outer periphery of the 1 st insulating layer, further extrusion-coating a 3 rd layer having a desired thickness on the outer periphery of the 2 nd insulating layer as needed, and then sequentially extrusion-coating the insulating-coated layers by repeating the extrusion-coating process. The multilayer insulating layer formed in this way preferably has an overall thickness in the range of 50 to 180 μm in terms of the total layers. If the overall thickness of the multilayer insulating layer is too thin, the electrical characteristics of the resulting insulated wire may be greatly degraded, making it unsuitable for practical use, whereas if it is too thick, it may be unsuitable for miniaturization, making coil processing difficult, and the like. A more preferable range of the thickness of the entire multilayer insulating layer is 60 to 150 μm. In this case, the thickness of each insulating layer constituting the multi-layer insulating layer is preferably selected from the range of 20 to 60 μm so that the thickness of the entire layer falls within the above range.

Regarding the thickness of the multilayer insulating layer, when importance is attached to flexibility of the insulated wire, the thickness of the innermost insulating layer is preferably within the above range and thinner than the thickness of the outer insulating layer.

The insulated wire of the present invention exhibits high heat resistance of class F or higher, which has not been achieved in the past, and is excellent in thermal shock resistance, scratch resistance, and flexibility before and after heating. The insulated wire of the present invention having the above characteristics can be used not only for conventional applications but also for electric/electronic devices that generate heat or electric/electronic devices installed in an environment where the ambient temperature rises and falls, and is particularly useful for coil applications, particularly coil applications requiring heat resistance of class F (heat resistance index 155 ℃).

As one embodiment of a preferred transformer using the insulated wires of the present invention, for example, the insulated wires 10 and 20 shown in fig. 1, a transformer shown in fig. 2 can be exemplified. The transformer is a small-sized transformer, and specifically, an insulation barrier or an insulation tape layer is not assembled in the winding bobbin 2 inserted into the ferrite core 1, but the insulated electric wire of the present invention is wound as the primary winding wire 4 and the secondary winding wire 6. The transformer has excellent electrical characteristics because of the use of the insulated wire of the present invention, and exhibits high reliability while maintaining insulation under conventional processing conditions and use environments, and also exhibits high reliability while maintaining insulation under severe processing conditions and use environments. The insulated wire according to the present invention can be used for other types of transformers, for example, a transformer having a conventional structure shown in fig. 3. Therefore, the transformer of the present invention includes the transformer of the conventional structure shown in fig. 3 in addition to the preferred transformer shown in fig. 2.

[ examples ]

The following examples are provided to explain the present invention more specifically, but the scope of the present invention is not limited by the examples.

Examples 1 to 10 and comparative examples 1 to 6

Insulated wires 10 shown in fig. 1(a) were produced in examples 1 and 2 and comparative example 1, and insulated wires 20 shown in fig. 1(b) were produced in examples 3 to 10 and comparative examples 2 to 6. In these examples and comparative examples, "layer 1" in table 1 corresponds to the "innermost insulating layer" of the insulated electric wire. In addition, "layer 2" in table 1 corresponds to "outermost insulating layer" in examples 1 and 2 and comparative example 1, and corresponds to "intermediate insulating layer" in examples 3 to 10 and comparative examples 2 to 6. The "layer 3" in Table 1 corresponds to the "outermost insulating layer" in examples 3 to 10 and comparative examples 2 to 6.

A annealed copper wire having a wire diameter of 1.0mm was prepared as a conductor. Each of the thermoplastic resins shown in table 1 was extruded in sequence onto the conductor so as to have a film thickness shown in table 1, respectively, to coat the conductor, thereby producing an insulated wire 10 or 20 having a conductor 11 or 21, an innermost insulating layer 12 or 22, an intermediate insulating layer 23, and an outermost insulating layer 13 or 24 as required.

With respect to the produced insulated electric wire, various characteristics shown below were tested.

The thermoplastic resins used in examples 1 to 10 and comparative examples 1 to 6 are shown below, and their melting points, storage moduli at 25 ℃ and storage moduli at 300 ℃ are shown in table 1. The thermoplastic resins used are all crystalline.

PEEK: PEEK450G (trade name, manufactured by Victrex corporation)

Modified PEEK: AvaPicre AV-650 (trade name, manufactured by Solvay Co., Ltd.)

Thermoplastic PI: AURUM PL450C (trade name, manufactured by Mitsui chemical Co., Ltd.)

PPS: DIC-PPS FZ-2100 (trade name, manufactured by DIC Co., Ltd.)

SPS: XAREC S105 (trade name, manufactured by shingling Co., Ltd.)

PA 66: FDK-1 (trade name, manufactured by Unitika Co., Ltd.)

PBN: TQB-KT (trade name, manufactured by Di chemical company)

ETFE: fluon ETFE C-55AP (trade name, manufactured by Asahi glass Co., Ltd.)

(A) Thermal shock (Annex3.0kV) test

The respective insulated electric wires manufactured in examples and comparative examples were evaluated for thermal shock properties by a test method in accordance with IEC standard 60950. That is, 10 turns of an insulated wire were wound around a mandrel having a diameter of 10mm while applying a load of 9.4kg, and heated at 250 ℃ for 1 hour, further heated at 175 ℃ for 21 hours and at 225 ℃ for 3 hours in a cycle, and further kept in an environment having a humidity of 95% at 30 ℃ for 48 hours. After that, a voltage of 3000V was applied for 1 minute, and it was judged as passed unless short-circuited. After that, pressurization was performed until the pressure was destroyed, and as a result, the case where the destruction voltage was 4000V or more was expressed as "excellent", and the case where the destruction voltage was 4000V or less was expressed as "o". For the determination, 5 samples (n is 5) were evaluated, and as long as 1 short circuit occurred, it was regarded as a failure and indicated by an "x". In the thermal shock test, if the result is "pass (evaluation is" o "or more)", the thermal shock resistance required for coil applications is satisfied. Further, it is easy to know the heat resistance that can satisfy the heat resistance class F (heat resistance index 155 ℃ C.) required for insulated electric wires in recent years.

(B) Flexibility test

The flexibility of the resulting insulated wire after heating was evaluated. The insulated wire was heated at 250 ℃ for 30 minutes, cooled, and tightly wound on a mandrel bar having a diameter of 10mm for 10 turns in such a manner that the wire is in contact with the wire, and observed by a microscope at a magnification of 50. It was judged as acceptable if no abnormality such as cracking or film bulging was observed in the insulating layer of the insulated electric wire, and it is indicated by ". smallcircle" in Table 1. The insulated wire was judged to be defective when abnormality such as cracking or film bulging was observed in the insulating layer of the insulated wire, and is indicated by an "x" in table 1. In the insulated wire, since the flexibility test after heating is an accelerated test (test under severe conditions), if the flexibility test after heating at 250 ℃ for 30 minutes is "acceptable", it is needless to say that the flexibility test before heating at 250 ℃ for 30 minutes is also "acceptable".

(C) Damage resistance (reciprocating wear test)

The scratch resistance was evaluated by a reciprocating abrasion test using a reciprocating abrasion tester. The reciprocating abrasion tester scratches the surface of the insulated wire with a constant load applied by a needle, and measures the number of times the conductor is exposed on the surface of the coating film, thereby making it possible to evaluate the strength of the coating film. The scratch resistance was evaluated by determining whether the number of reciprocating abrasion times reached 50 times with a load of 500 g. The number of times of the reciprocating wear was 50 or more was regarded as "good" and indicated by ". smallcircle" in Table 1. The case where the number of times was 70 or more was regarded as particularly excellent in scratch resistance, and is represented by ". circleincircle" in table 1. The case where the number of reciprocating abrasion was less than 50 times was regarded as a failure and indicated by "X" in Table 1.

As shown in table 1, the insulated wires of examples 1 to 10 in which the thermoplastic resins forming the innermost insulating layer and the outer insulating layer satisfy the conditions of the present invention were acceptable in any of the electrical heat resistance test, the flexibility test after heating, and the reciprocating abrasion test, regardless of whether the insulated wires were two-layer insulated wires or three-layer insulated wires. It is understood that according to examples 1 to 10, insulated wires satisfying the requirement for improvement in heat resistance and having the necessary characteristics such as thermal shock resistance, flexibility before and after heating, and scratch resistance required for coil applications can be manufactured.

In particular, when a polyamide resin is used for the outermost insulating layer, the result is more excellent in scratch resistance. Therefore, it is understood that the configurations using the PEEK resin or the modified PEEK resin for the innermost insulating layer and the polyamide resin for the outermost insulating layer as shown in examples 3, 5,6, 8, and 10 can most obtain the necessary characteristics such as flexibility before and after heating and scratch resistance.

In addition, compared to the insulated wires having two insulating layers of examples 1 and 2, the insulated wires having three insulating layers of examples 3 to 10 have a smaller difference in storage modulus between the insulating layers, and can form the innermost insulating layer 12 having a high storage modulus as thin as necessary, and thus the flexibility before and after heating is further improved. Therefore, if the purpose is to further improve the flexibility of the insulated wire, it is preferable to have a three-layer structure of the multilayer insulating layer.

Thus, the insulated wire of the present invention has both the necessary characteristics, and therefore, an electric/electronic device including the insulated wire of the present invention exhibits high reliability in maintaining insulation even under severe processing conditions and use environments.

On the other hand, the innermost insulating layers of the insulated wires of comparative examples 1 and 2 were not formed of a resin having sufficient heat resistance, and thus the thermal shock test, i.e., electrical heat resistance, was poor. In addition, since the outer insulating layer of the insulated wire of comparative example 2 is formed of a thermoplastic resin having a storage modulus larger than that of the innermost insulating layer, swelling of the coating film was observed in the flexibility test, and the interlayer adhesion force was low.

The outermost insulating layer of the insulated wire of comparative example 3 is formed of a thermoplastic resin having a storage modulus larger than that of the intermediate insulating layer, and the intermediate insulating layer of the insulated wire of comparative example 4 is formed of a thermoplastic resin having a storage modulus larger than that of the innermost insulating layer, and thus the interlayer adhesion force is low as in comparative example 2. In addition, due to the effect of the rise of the coating film, the scratch resistance was lower than those of examples 1 and 5, although a thermoplastic resin having a high storage modulus was used for the outermost insulating layer.

The intermediate insulating layer and the outermost insulating layer of the insulated wire of comparative example 5 are resins having a melting point of 260 ℃ or less, and the coating film is melted by heating, and therefore, the flexibility after heating is poor.

The outermost insulating layer of the insulated wire of comparative example 6 is formed of a thermoplastic resin having a storage modulus (25 ℃) of less than 1000MPa, and thus the scratch resistance is poor.

The present invention has been described above together with embodiments thereof, but it is not intended that the inventors be limited to any details for the purpose of describing the invention, unless otherwise specified in the application, and that they be interpreted as having the widest scope without departing from the spirit and scope of the invention as set forth in the appended claims.

The present invention claims priority of Japanese patent application laid-open in Japanese application No. 2012-263748 based on the year 2012, 11, 30, and the present application refers to the content of the above patent application and the content thereof is incorporated into the present specification as a part of the description of the present specification.

Description of the symbols

1: ferrite magnetic core

2: winding bobbin

3: insulation barrier

4: primary winding wire

4 a: conductor

4b, 4c, 4 d: insulating layer

5: insulating adhesive tape

6: secondary winding wire

6 a: conductor

6b, 6c, 6 d: insulating layer

10. 20: insulated wire

11. 21: conductor

12. 22: innermost insulating layer

13. 24: outermost insulating layer

23: intermediate insulating layer

Claims (4)

1. An insulated wire having 3 insulating layers covered with a conductor,

the innermost insulating layer of the 3 insulating layers is an insulating layer formed of at least one thermoplastic resin having a storage modulus at 300 ℃ of 10MPa or more and selected from the group consisting of a polyether ether ketone resin, a modified polyether ether ketone resin, and a thermoplastic polyimide resin,

the outer insulating layer other than the innermost insulating layer includes an insulating layer formed of polyamide 66 which is a crystalline thermoplastic resin having a melting point of 260 ℃ or higher and a storage modulus at 25 ℃ of 1000MPa or higher,

the adjacent insulating layers are in the following relationship: the storage modulus at 25 ℃ of the thermoplastic resin of the insulating layer located on the outer side is smaller than the storage modulus at 25 ℃ of the thermoplastic resin of the insulating layer located on the inner side.

2. The insulated wire according to claim 1, wherein the outermost layer of the 3-layer insulation layer is polyamide 66.

3. The insulated wire according to claim 1, wherein the intermediate layer of the 3-layer insulation layer comprises a thermoplastic resin having a melting point of 250 ℃ or higher.

4. An electric/electronic device characterized by using the insulated electric wire according to any one of claims 1 to 3 as a winding wire and/or a lead wire of a transformer mounted in the electric/electronic device.