Multi-layer soft magnetic alloy ribbon and method of manufacturing the same, and laminated core and method of manufacturing the same

Abstract

To provide a multi-layer soft magnetic alloy ribbon that is compatible with a low cost and in which peel strength of a soft magnetic alloy is high.SOLUTION: In a multi-layer soft magnetic alloy ribbon, two or more soft magnetic alloy ribbons with a thickness of 10-50 μm are stacked and joined to each other. A resin layer for jointing is provided between the soft magnetic alloy ribbons. A resin of the resin layer has a melting point Tm of 80-170°C and a thermal decomposition start temperature of 360°C or higher. In addition, preferably, peel strength of the soft magnetic alloy ribbon at one end in the lamination direction of the soft magnetic alloy ribbon is 0.01 N / mm or more, in the multi-layer soft magnetic alloy ribbon.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a multilayer soft magnetic alloy ribbon and a manufacturing method thereof, and a laminated core and a manufacturing method thereof. [Background technology]

[0002] Soft magnetic alloy ribbons made of soft magnetic alloy materials, such as Fe-based amorphous alloys and Fe-based nanocrystalline alloys, are manufactured by rapidly cooling and solidifying a molten alloy. A typical manufacturing method involves discharging the molten alloy onto a rotating chill roll, rapidly cooling it, and solidifying it to obtain a thin soft magnetic alloy ribbon. The Fe-based amorphous alloy ribbons and Fe-based nanocrystalline alloy ribbons obtained by this method are only thin, with thicknesses of about 10 to 50 μm. These soft magnetic alloy ribbons (such as Fe-based amorphous alloy ribbons and Fe-based nanocrystalline alloy ribbons) have excellent magnetic properties (for example, low iron loss and high saturation magnetic flux density) and are used as various core materials.

[0003] When manufacturing a core from a soft magnetic alloy ribbon, there are two methods: winding it to make a circular core, or cutting or punching it to make individual pieces and then laminating them to make a laminated core. Demand for laminated cores is increasing due to the flexibility of the core shape.

[0004] When manufacturing a laminated core, if a thin (about 10 to 50 μm) soft magnetic alloy ribbon is used, problems arise such as poor handling of the thin soft magnetic alloy ribbon and the labor required for manufacturing each piece and laminating them. Therefore, a method has also been used in which a multilayer soft magnetic alloy ribbon is manufactured by laminating a plurality of soft magnetic alloy ribbons, and the multilayer soft magnetic alloy ribbon is used to manufacture a core.

[0005] For example, Patent Publication No. 2021-002553 discloses a magnetic material comprising a soft magnetic amorphous alloy ribbon and a resin layer disposed on at least one of a pair of opposing main surfaces of the soft magnetic amorphous alloy ribbon, in which the resin used for the resin layer is a polyamide-imide resin having a linear expansion coefficient of 40 ppm / °C or less. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-002553 Summary of the Invention [Problem to be solved by the invention]

[0007] When soft magnetic alloy ribbons are laminated or processed, stress is applied, which tends to deteriorate their magnetic properties. One method for restoring these deteriorated magnetic properties is to perform heat treatment. For example, heat treatment can be performed at temperatures of 300 degrees or higher.

[0008] Multilayer soft magnetic alloy ribbons are often bonded via a resin layer, and heat-resistant resins have been used in consideration of the heat treatment described above. For example, Japanese Patent Application Laid-Open No. 2021-002553 discloses that polyamide-imide resins preferably have a glass transition temperature of 250°C or higher. Furthermore, polyamide-imide resins require the thermocompression bonding state to be maintained for several minutes, which requires a batch bonding method when stacking and bonding multilayer soft magnetic alloy ribbons. This has posed a problem in productivity.

[0009] Soft magnetic alloy ribbons are laminated or wound and used in cores of transformers, motors, etc., and these products are required to be low-cost. Therefore, multilayer soft magnetic alloy ribbons are also required to be low-cost. Furthermore, multilayer soft magnetic alloy ribbons are often processed to form cores, and the soft magnetic alloy ribbons of the multilayer soft magnetic alloy ribbons are required to have high peel strength so that they do not peel off during processing. An object of the present disclosure is to provide a multilayer soft magnetic alloy ribbon that is low in cost and has high peel strength. [Means for solving the problem]

[0010] A multilayer soft magnetic alloy ribbon according to a first aspect of the present disclosure is a multilayer soft magnetic alloy ribbon in which two or more soft magnetic alloy ribbons having a thickness of 10 to 50 μm are stacked and bonded to each other, and a resin layer for bonding is provided between the soft magnetic alloy ribbons, and the resin of the resin layer has a melting point Tm of 80°C or more and 170°C or less and a thermal decomposition starting temperature of 360°C or more.

[0011] A method for manufacturing a multilayer soft magnetic alloy ribbon according to a second aspect of the present disclosure includes preparing a plurality of soft magnetic alloy ribbons, forming a resin layer on at least one surface of the soft magnetic alloy ribbons, stacking the soft magnetic alloy ribbons so that the resin layer is disposed between the soft magnetic alloy ribbons, pressurizing and heating the soft magnetic alloy ribbons, and manufacturing a multilayer soft magnetic alloy ribbon bonded to each other, wherein a resin having a melting point Tm of 80°C or more and 170°C or less and a thermal decomposition onset temperature of 360°C or more is used for the resin layer.

[0012] A laminated core according to a third aspect of the present disclosure is a laminated core formed by stacking a plurality of multilayer core pieces, wherein the multilayer core pieces are formed by stacking two or more layers of soft magnetic alloy ribbons having a thickness of 10 to 50 μm and bonding them together, and a resin layer for bonding is provided between the soft magnetic alloy ribbons, and the resin in the resin layer has a melting point Tm of 80°C or more and 170°C or less and a thermal decomposition starting temperature of 360°C or more.

[0013] In a method for manufacturing a laminated core according to a fourth aspect of the present disclosure, the multilayer soft magnetic alloy ribbon according to the first aspect is processed to prepare multilayer core laminations, and the multilayer core laminations are laminated. [Effects of the Invention]

[0014] According to the present disclosure, a relatively inexpensive resin can be used, thereby enabling low costs to be achieved. Furthermore, according to the present disclosure, a multilayer soft magnetic alloy ribbon having high peel strength can be provided. Furthermore, according to the present disclosure, a method for manufacturing the multilayer soft magnetic alloy ribbon can be provided. Furthermore, according to the present disclosure, a laminated core using the multilayer soft magnetic alloy ribbon can be provided. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a plan view of a split core according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a perspective view of a laminated core according to one embodiment of the present disclosure. [Figure 3] FIG. 1 is a diagram showing core loss before and after heat treatment of an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0016] [Multilayer soft magnetic alloy ribbon] A multilayer soft magnetic alloy ribbon according to an embodiment of the present disclosure is a multilayer soft magnetic alloy ribbon in which two or more soft magnetic alloy ribbons having a thickness of 10 to 50 μm are stacked and bonded to each other, and a bonding resin layer is provided between the soft magnetic alloy ribbons, and the resin in the resin layer has a melting point Tm of 80°C or higher and 170°C or lower and a thermal decomposition starting temperature of 360°C or higher.

[0017] The resin in the present disclosure has a melting point Tm of 80°C or higher and 170°C or lower, and the heat treatment temperature of the soft magnetic alloy ribbon (for example, 300°C to 350°C) exceeds the melting point Tm of the resin. However, the resin has a thermal decomposition starting temperature of 360°C or higher, and the resin does not disappear even if the heat treatment is performed at, for example, 350°C. Therefore, when the temperature returns to room temperature after the heat treatment, the resin layer using this resin functions as an adhesive layer, enabling bonding between the soft magnetic alloy ribbons. Furthermore, the resin in the present disclosure preferably has a 5% weight loss temperature around 400°C or higher. Furthermore, the resin in the present disclosure preferably has a glass transition temperature Tg of 0°C or lower.

[0018] Therefore, the resin in the present disclosure is a resin that can be heat-treated. Moreover, a resin that can be reduced in cost can be used instead of a heat-resistant resin. Examples of such resins include polyethylene resin and polypropylene resin. Olefin-based polymer compounds, such as polyethylene resin and polypropylene resin, are called polyolefins.

[0019] In the multilayer soft magnetic alloy ribbon according to the present disclosure, the peel strength of the soft magnetic alloy ribbon at one end in the lamination direction of the soft magnetic alloy ribbon is preferably 0.01 N / mm or more. More preferably, it is 0.03 N / mm or more. When the peel strength is 0.01 N / mm or more, peeling of the soft magnetic alloy ribbon can be suppressed when the multilayer soft magnetic alloy ribbon is processed. For example, when the multilayer soft magnetic alloy ribbon is punched, peeling of the soft magnetic alloy ribbon at the end of each punched piece can be suppressed. Furthermore, when the peel strength is 0.03 N / mm or more, the effect of suppressing peeling of the soft magnetic alloy ribbon can be further enhanced.

[0020] For example, a multilayer soft magnetic alloy ribbon having a width of 30 mm is prepared, and a peel test is performed on the soft magnetic alloy ribbon on the outermost surface to measure the force (N) at the time of peeling. When the force value is X (N), this peel strength is expressed as XN / 30 mm. This value is divided by the width of the soft magnetic alloy ribbon, 30 mm, to obtain (X / 30) N / mm. In the case of a multilayer soft magnetic alloy ribbon having a width other than 30 mm, a similar test can be performed and the value can be divided by the width.

[0021] The resin layer using the resin in the present disclosure preferably has a thickness of 2 μm or less. More preferably, it is 1 μm or less. Furthermore, it is preferably 0.9 μm or less, and more preferably 0.8 μm or less. By thinning the resin layer, the space factor of the laminated core formed using the multilayer soft magnetic alloy ribbon can be increased. Furthermore, the resin layer using the resin in the present disclosure can be formed into a resin layer with high peel strength even though it is thin. For example, the resin layer can have a thickness of 1 μm or less and a peel strength of 0.01 N / mm or more. Furthermore, the thickness of the resin layer is preferably 0.2 μm or more, more preferably 0.3 μm or more, and even more preferably 0.4 μm or more. Here, the thickness of the resin layer is calculated from the difference in thickness between a desired number N of soft magnetic alloy ribbons without a resin layer stacked on top of each other and a multilayer soft magnetic alloy ribbon with N layers having a resin layer. Specifically, the thickness of the resin layer is calculated by dividing (the thickness of the multilayer soft magnetic alloy ribbon with the number N of resin layers) - (the thickness of the soft magnetic alloy ribbon without a resin layer stacked on top of each other by N-1).

[0022] Furthermore, polyolefin is made from carbon (C) and hydrogen (H), so even if it is burned it turns into water (H2O) and carbon dioxide (CO2), making it an environmentally friendly resin. Furthermore, the development of bioplastics made from raw materials such as sugarcane is also progressing. By using bioethylene and biopolypropylene, it is possible to create more environmentally friendly multilayer soft magnetic alloy ribbons.

[0023] The soft magnetic alloy ribbon in the present disclosure is preferably made of an amorphous alloy or a nanocrystalline alloy. The amorphous alloy ribbon made of an amorphous alloy is preferably an Fe-based amorphous alloy ribbon. Furthermore, the nanocrystalline alloy ribbon made of a nanocrystalline alloy is preferably an Fe-based nanocrystalline alloy ribbon. The soft magnetic alloy ribbon in the present disclosure may be an amorphous alloy ribbon or a nanocrystalline alloy ribbon.

[0024] [Method for manufacturing multilayer soft magnetic alloy ribbon] A method for producing a multilayer soft magnetic alloy ribbon according to an embodiment of the present disclosure will be described. First, a plurality of soft magnetic alloy ribbons are prepared. Here, it is preferable to prepare a wound body in which the soft magnetic alloy ribbons are wound in a coil shape. Then, a resin layer for bonding is formed on at least one surface of each soft magnetic alloy ribbon. The soft magnetic alloy ribbon is flat and has two opposing main surfaces. The resin layer may be formed on only one of the main surfaces, or on both of the main surfaces. Note that forming a resin layer on only one of the main surfaces is advantageous in terms of improving the space factor. In the case of a wound body in which a soft magnetic alloy ribbon is wound in a coil shape, the soft magnetic alloy ribbon is unwound from the wound body, and a resin layer can be formed on one or both surfaces of the unwound body. For example, the resin layer can be formed using a gravure coater.

[0025] The resin used for the resin layer has a melting point Tm of 80° C. or more and 170° C. or less, and a thermal decomposition starting temperature of 360° C. or more. For example, a polyethylene resin or a polypropylene resin can be used. The resin layer can be formed using an aqueous dispersion obtained by mixing the polyolefin granules with a dispersant such as water.

[0026] A plurality of soft magnetic alloy ribbons on which resin layers have been formed are stacked one on top of the other. For example, a multilayer soft magnetic alloy ribbon can be constructed by stacking soft magnetic alloy ribbons having a resin layer formed on one surface in the order of alloy ribbon, resin layer, alloy ribbon, and resin layer, and then stacking a soft magnetic alloy ribbon without a resin layer on top of the multilayer body having a resin layer formed on the top surface. Then, the multi-layered soft magnetic alloy ribbons are bonded together by applying pressure and heat, thereby obtaining a multi-layered soft magnetic alloy ribbon in which the soft magnetic alloy ribbons are bonded together.

[0027] For example, a wound body of a plurality of soft magnetic alloy ribbons is prepared, and the resin layer can be formed while the soft magnetic alloy ribbons are unwound from the wound body and transported. Furthermore, the soft magnetic alloy ribbons on which the resin layers have been formed can be stacked and bonded while being transported. That is, the process can be carried out continuously while the soft magnetic alloy ribbon is being transported. The resin of the present disclosure can bond soft magnetic alloy ribbons by applying pressure and heat for a short period of time, and by continuously transporting soft magnetic alloy ribbons stacked in multiple layers via resin layers while applying pressure and heat, a bonded multilayer soft magnetic alloy ribbon can be obtained. For example, stacked soft magnetic alloy ribbons can be passed between a pair of heated rolls to form a multi-layered soft magnetic alloy ribbon bonded to each other. Moreover, by sandwiching the ribbon between heated plates, a bonded multilayer soft magnetic alloy ribbon can also be obtained. At this time, the temperature of the roll or the heated plate is preferably set to a temperature of not less than the melting point Tm of the resin and not more than 350°C.

[0028] Alternatively, the multilayer soft magnetic alloy ribbon can be wound around a roll to obtain a wound body of the multilayer soft magnetic alloy ribbon. Furthermore, according to the present disclosure, it is also possible to manufacture multilayer soft magnetic alloy ribbons in an integrated line called roll-to-roll, which is suitable for mass production.

[0029] The number of layers of the soft magnetic alloy ribbons in the multilayer soft magnetic alloy ribbon can be determined depending on the purpose. When winding the multilayer soft magnetic alloy ribbon, if the number of layers is too large, winding may become difficult. Therefore, the number of layers is preferably 25 or less, more preferably 20 or less, more preferably 15 or less, and more preferably 10 or less. Also, the number of layers is preferably 2 or more, more preferably 3 or more, more preferably 4 or more, and more preferably 5 or more.

[0030] The multilayer soft magnetic alloy ribbon is processed into pieces of a predetermined shape by cutting, punching, or the like. The pieces are then laminated to form a laminated core. The laminated core is used as a core for various transformers and coils, and also as a motor core.

[0031] The magnetic properties of soft magnetic alloy ribbons may be deteriorated due to stress. In particular, the deterioration of the magnetic properties may occur after processing. The multilayer soft magnetic alloy ribbon of the present disclosure can be heat-treated, and can be subjected to heat treatment to recover the magnetic properties deteriorated due to stress such as processing.

[0032] Example 1 An Fe-based amorphous alloy ribbon (HB1M manufactured by Hitachi Metals, Ltd.) was used as the soft magnetic alloy ribbon. Five wound bodies were prepared, each consisting of a 30 mm wide, 25 μm thick Fe-based amorphous alloy ribbon wound into a coil. An aqueous dispersion of polyethylene resin was applied to one side of the Fe-based amorphous alloy ribbon unwound from four of the wound bodies using a gravure coater to a thickness of 1 to 1.5 μm to form a resin layer. This polyethylene resin had a melting point (Tm) of approximately 100°C and a thermal decomposition onset temperature of approximately 400°C. The thermal decomposition onset temperature was defined as the temperature at which the TG curve lost linearity and began to decline, and the DTA curve lost linearity or began to decline, as measured under inert gas using a differential thermal analyzer.

[0033] In this example, the Fe-based amorphous alloy ribbons formed with resin layers were wound into four wound bodies. Next, from the four wound bodies of the Fe-based amorphous alloy ribbons formed with resin layers, the Fe-based amorphous alloy ribbons were unwound and transported, and were stacked in the following order: alloy ribbon, resin layer, alloy ribbon, resin layer, alloy ribbon, resin layer, alloy ribbon, resin layer. An Fe-based amorphous alloy ribbon without a resin layer (the Fe-based amorphous alloy ribbon unwound from the fifth wound body) was stacked on the upper resin layer to form a five-layer Fe-based amorphous alloy ribbon. Here, the five-layer Fe-based amorphous alloy ribbon was produced in the transported state. Then, the five-layer Fe-based amorphous alloy ribbon was passed between a pair of rolls whose roll temperatures were set to 80°C to 200°C, and pressurized and heated to produce a five-layer Fe-based amorphous alloy ribbon in which the Fe-based amorphous alloy ribbons were bonded to each other. The five-layer Fe-based amorphous alloy ribbon was wound around a roll, and the conveying speed of the Fe-based amorphous alloy ribbon when passing between the pair of rolls was set to 3.5 m / min.

[0034] In Example 1, the relationship between the roll temperature and the peel strength and the resin layer thickness is shown in Table 1. The resin layer thickness was measured by measuring the thickness of a five-layered Fe-based amorphous alloy ribbon. Five layers of Fe-based amorphous alloy ribbons without a resin layer were also stacked, and the thicknesses were measured. The difference in thickness was divided by 4 to obtain the resin layer thickness. The thickness was measured using a micrometer, and the average value was calculated from measurements at 10 locations. The peel strength was measured by manually rolling up a small portion of the outermost Fe-based amorphous alloy ribbon of a five-layer Fe-based amorphous alloy ribbon. Then, a hole was made in the rolled-up portion with a hand punch. The sensor part of the autograph or an attached hook was then hooked into the hole. The sensor was then moved at a constant speed to read the force (N) applied when peeled. The read value was taken as the peel strength in units of N / 30 mm, and the value obtained by dividing the read value by the width of 30 mm was taken as the peel strength in units of N / mm. The peel strength values ​​in N / 30 mm and N / mm are shown in Table 1.

[0035] It can be seen that increasing the roll temperature increases the peel strength. The roll temperature can be set according to the required peel strength. In particular, when the roll temperature was 100°C, the peel strength was 0.01 N / mm or more, which was sufficient. Furthermore, when the roll temperature was 120°C or higher, a peel strength of 0.03 N / mm or more was obtained, which was even more sufficient. Furthermore, the resin layer thickness was 1.0 μm or less in all cases, which allowed for a sufficiently thin resin layer, and the effect of increasing the space factor could be expected. In particular, Samples 2 to 5 had a thin resin layer thickness of 0.75 μm, and a sufficient peel strength was obtained, and multilayer soft magnetic alloy ribbons with thin resin layers and high peel strength could be obtained.

[0036] [Table 1]

[0037] Example 2 Using the sample of Example 1, a laminated core for a motor was produced. The multilayer soft magnetic alloy ribbon (five-layer Fe-based amorphous alloy ribbon) of Sample 5 in Example 1 was used to punch out divided core pieces 1 having the shape shown in Fig. 1. The divided core pieces (multilayer core pieces) 1 consisted of five layers of Fe-based amorphous alloy ribbon. The divided core pieces 1 were punched out using a punch machined into the shape of a core piece and a die having a hole into which the punch could be inserted.

[0038] 360 of these split core pieces 1 were stacked to produce the split core (laminated core) 2 shown in Figure 2. This split core 2 is made up of 1,800 laminated Fe-based amorphous alloy ribbons. The split core pieces 1 were bonded together using a one-component thermosetting acrylic adhesive with a viscosity of 50 mPa·s. The bonding was carried out at 170°C for 2 hours. Six of these split cores 2 were fabricated and combined to fabricate a cylindrical laminated core for a motor with an outer diameter of 50 mm and an inner diameter of 26 mm, which can be used as a stator for a motor.

[0039] It was found that the multilayer soft magnetic alloy ribbon of the present disclosure can be punched into multilayer core pieces, and that even when the punched multilayer core pieces are stacked to produce a laminated core, no shape defects occur and the laminated core can be used. Furthermore, no peeling of the soft magnetic alloy ribbon occurs after punching. The multilayer soft magnetic alloy ribbon of the present disclosure can be formed into multilayer core pieces by using a processing method such as cutting or punching, and the multilayer core pieces can be stacked to produce a laminated core, which can be used for various applications such as the motor described above, as well as transformers and choke coils. The laminated core can be fixed to a housing by known means such as bonding or potting.

[0040] [Confirmation of heat processability of the resin of the present disclosure] An Fe-based amorphous alloy ribbon (HB1M manufactured by Hitachi Metals, Ltd.) was used as the soft magnetic alloy ribbon. A wound body was prepared in which an Fe-based amorphous alloy ribbon with a width of 50 mm and a thickness of 25 μm was wound into a coil. An aqueous dispersion of polyethylene resin was applied to one surface of the Fe-based amorphous alloy ribbon unwound from the wound body using a gravure coater to a thickness of 1 to 1.5 μm to form a resin layer. After drying, the resin layer was punched into a ring shape with an outer diameter of 43 mm and an inner diameter of 25 mm. In addition, the same Fe-based amorphous alloy ribbon was punched out into a ring shape with an outer diameter of 43 mm and an inner diameter of 25 mm without forming a resin layer.

[0041] Experimental Example 1 Thirty ring-shaped samples without a resin layer were stacked together, and a ring-shaped core sample was prepared without bonding the stacked samples together. Experimental Example 2 Thirty ring-shaped samples each having a resin layer formed thereon were stacked together, and then heated to 150°C under a pressure of 0.1 MPa to prepare a ring-shaped core sample in which each Fe-based amorphous alloy ribbon was bonded. Experimental Example 3 The ring-shaped core sample of Experimental Example 2 was heat-treated in a nitrogen atmosphere at 330° C. After the heat treatment, the Fe-based amorphous alloy ribbons were bonded together, and the shape before the heat treatment was maintained.

[0042] Using the core samples of Experimental Examples 1, 2, and 3, core loss was measured at 1 kHz and 1 T. The measuring instrument used was an Iwatsu SY-8232, and the primary and secondary windings were 30 turns. The results are shown in Table 2 and Figure 3. As shown in Table 2 and Figure 3, the core loss worsened in the core sample (Experimental Example 2) in which the multilayer soft magnetic alloy ribbon was bonded. This is thought to be due to the influence of the stress caused by the formation of the resin layer and bonding. However, as shown in Experimental Example 3, the core loss was almost completely recovered by performing heat treatment to relieve stress. It can be seen that the resin of the present disclosure allows for heat treatment for stress relief.

[0043] [Table 2]

Claims

1. A multilayer soft magnetic alloy ribbon in which two or more layers of soft magnetic alloy ribbons having a thickness of 10 to 50 μm are laminated and joined to each other, a resin layer for bonding is provided between the soft magnetic alloy ribbons, The resin of the resin layer has a melting point Tm of 80° C. or higher and 170° C. or lower, and a thermal decomposition starting temperature of 360° C. or higher.

2. 2. The multi-layered, soft magnetic alloy ribbon according to claim 1, wherein a peel strength of the soft magnetic alloy ribbon at one end in the lamination direction of the soft magnetic alloy ribbon is 0.01 N / mm or more.

3. 3. The multilayered soft magnetic alloy ribbon according to claim 1, wherein the soft magnetic alloy ribbon is made of an amorphous alloy or a nanocrystalline alloy.

4. A method for manufacturing a multilayer soft magnetic alloy ribbon bonded to one another by preparing a plurality of soft magnetic alloy ribbons, forming a resin layer on at least one surface of the soft magnetic alloy ribbons, stacking the plurality of soft magnetic alloy ribbons so that the resin layer is disposed between the soft magnetic alloy ribbons, and applying pressure and heat thereto, A method for producing a multilayer soft magnetic alloy ribbon, wherein the resin layer uses a resin having a melting point Tm of 80°C or higher and 170°C or lower, and a thermal decomposition starting temperature of 360°C or higher.

5. 5. The method for producing a multilayer soft magnetic alloy ribbon according to claim 4, wherein a multilayer soft magnetic alloy ribbon formed by stacking a plurality of soft magnetic alloy ribbons is passed between a pair of heated rolls so that the resin layer is disposed between the soft magnetic alloy ribbons, thereby obtaining multilayer soft magnetic alloy ribbons joined to each other.

6. The method for producing a multilayer soft magnetic alloy ribbon according to claim 5, wherein the temperature of the pair of heated rolls is equal to or higher than the melting point Tm and equal to or lower than 350°C.

7. A laminated core formed by laminating a plurality of multilayer core pieces, The multilayer core piece is a laminated core in which two or more layers of soft magnetic alloy ribbons having a thickness of 10 to 50 μm are laminated and bonded to each other, and a resin layer for bonding is provided between the soft magnetic alloy ribbons, and the resin in the resin layer has a melting point Tm of 80°C or higher and 170°C or lower and a thermal decomposition starting temperature of 360°C or higher.

8. The multilayer soft magnetic alloy ribbon according to claim 1 is processed to prepare a multilayer core piece, A method for manufacturing a laminated core by stacking the multilayer core pieces.

9. The method for manufacturing a laminated core according to claim 8, wherein the multilayer soft magnetic alloy ribbon is processed by cutting or punching.

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