JP2011254066A - Fe-BASED NANO CRYSTAL ALLOY THIN BAND LAMINATE, MAGNETIC CORE FOR ANTENNA AND ANTENNA - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Fe-based nano crystal alloy thin band laminate capable of being integrally treated due to large adhesive force between alloy thin bands after heat treatment, for solving problems that the alloy thin bands detach from each other and adhesive strength is low after the heat treatment at 500°C or higher of a conventional amorphous alloy thin band laminate for the Fe-based nano crystal alloy thin band laminate treated by application of polyimide resin on its surface and thermocompression thereof.SOLUTION: An Fe-based nano crystal alloy thin band laminate is a laminate in which a plurality of Fe-based nano crystal alloy thin bands are laminated. The neighboring Fe-based nano crystal alloy thin bands are adhered to each other with a polyimide resin having a structure of biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PPD). An average of resin thickness of the polyimide resin is equal to or greater than 2 μm and equal to or less than 16 μm, and three-point flexural strength is equal to or greater than 0.3 Pa.

Description

  The present invention relates to a laminated body in which Fe-based nanocrystalline alloy ribbons are laminated, and particularly to a laminated body that can be heat-treated at 500 ° C. or higher.

An amorphous magnetic ribbon is an excellent magnetic material. The amorphous alloy ribbon is produced by rapidly solidifying a molten alloy material by a single roll method or the like. Next, heat treatment at 300 to 500 ° C. is performed in order to bring out the original excellent magnetic properties after forming the desired toroidal shape or laminate shape for use as a magnetic core. Since the alloy ribbon becomes brittle after the heat treatment, the processing to the toroidal shape or the laminate shape needs to be performed before the heat treatment.
Conventionally, ferrite has been used as a magnetic core for an antenna. However, since it is a ceramic, when it is thinned, the mechanical strength is lowered, and there is a problem of breakage or cracking. Therefore, a laminate of a Co-based amorphous alloy ribbon that is superior in mechanical strength to ferrite is used as a magnetic core for an antenna for a radio wave wristwatch or a keyless entry of an automobile.

There are the following two production methods as a production method of a laminated body of amorphous alloy ribbons.
(A) Epoxy resin impregnation method After heat-treating the slit and cut alloy ribbons to the desired size, set the desired number of pieces in a laminating jig that can be easily disassembled, and put the epoxy resin between the alloy ribbons After impregnation and curing, the jig is disassembled and the laminate is taken out.
(B) Thermocompression bonding method of heat-resistant resin coated alloy ribbon After applying heat-resistant resin such as polyimide resin or polyamide-imide resin to the surface of amorphous alloy ribbon in advance, slitting and cutting to the desired size, multiple alloys After laminating the ribbon, it is integrated by thermocompression bonding to the laminating method to obtain a laminated body, and finally a heat treatment is performed.
In the method (A), since the ribbon is bonded and fixed with an epoxy resin after the heat treatment, it is not necessary to consider the temperature of the heat treatment. However, several hours are required for resin impregnation and curing, and man-hours for setting to and removing from a jig are required, resulting in a problem that productivity is very low. Moreover, since it is difficult to manage the amount of epoxy resin between the alloy ribbons, there is a drawback that the characteristic variation is large.
On the other hand, in the method (B), since the heat treatment is performed in the final step, the heat treatment temperature is restricted to be equal to or lower than the heat resistant temperature of the heat resistant resin, but the resin can be applied continuously and the productivity is high. Also, a few minutes is sufficient for the thermocompression bonding time. Since it is easy to obtain a constant resin thickness by a continuous coating apparatus, there is an advantage that the characteristic variation in the laminate is small.

The Fe-based nanocrystalline alloy ribbon is made of an amorphous alloy ribbon for an Fe-based nanocrystalline alloy that becomes a Fe-based nanocrystalline structure by heat treatment. Obtained by heat treatment at 500 ° C. or higher.
Even the polyimide resin having the most excellent heat resistance is difficult to withstand heat treatment at 500 ° C. or higher, so that it is difficult to apply the method (B), and the method (A) is adopted.

Patent Document 1 describes a laminated magnetic core in which a heat resistant resin such as a polyimide resin or a polyamideimide resin is applied to an amorphous alloy ribbon or an Fe-based nanocrystalline alloy ribbon and laminated.
In Patent Document 2, an Fe-based nanocrystalline alloy ribbon with the composition Fe _73.5 Cu ₁ Nb ₃ Si _14.5 B _6.5 (atomic%) is coated with an epoxy resin on the surface of the ribbon and laminated. An antenna using a body is described.
Patent Documents 3 and 4 describe a laminate in which a polyimide resin is applied on a Fe-based nanocrystalline alloy ribbon, laminated, and heat-treated.

JP 2002-164224 A JP 07-278763 A International Publication No. 2005/031767 JP-A-2005-81732

  Although the heat treatment temperature of the Fe-based nanocrystalline alloy ribbon is as high as 500 ° C. or higher, it is very difficult to apply the method (B) even with the polyimide resin having the highest heat resistance temperature. Patent Documents 1, 3, and 4 describe a laminate in which a polyimide resin is applied on a Fe-based nanocrystalline alloy ribbon, laminated, and heat-treated. Therefore, based on the contents described in paragraph (0045) of Patent Document 3 and paragraphs (0042) to (0045) of Patent Document 4, 3,3′-diaminodiphenyl ether (also known as 3,3′-oxydi) is used. A laminate was prepared using a polyimide resin composed of aniline (MODA)) and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA), and heat-treated at 550 ° C. As a result, there was almost no adhesive force between the alloy ribbons, and there was a problem that each alloy ribbon was easily peeled off. Although an attempt was made to lower the heat treatment temperature to 500 ° C., there was almost no adhesion between the alloy ribbons, and there was a problem that each alloy ribbon was easily peeled off.

  Therefore, in view of the above problems, the inventor applied an amorphous alloy ribbon for Fe-based nanocrystalline alloy ribbon coated with polyimide resin on the surface and heat-treated at 500 ° C. or higher even if the alloy thin film was heat-treated. An object of the present invention is to provide a Fe-based nanocrystalline alloy ribbon laminate having a large adhesive force between the strips and capable of being handled integrally.

  The inventor examined the combination of a diamine and an acid anhydride constituting a polyimide structure, and was applied to an amorphous alloy ribbon for an Fe-based nanocrystalline alloy ribbon, and then obtained by thermocompression bonding of the alloy ribbons. In the Fe-based nanocrystalline alloy ribbon laminate in which the laminate is heat-treated at 500 ° C. or higher, a polyimide resin having a large adhesive force between the alloy ribbons has been found.

That is, the present invention is a laminate in which a plurality of Fe-based nanocrystalline alloy ribbons are laminated, and the adjacent Fe-based nanocrystalline alloy ribbons are biphenyltetracarboxylic dianhydride (BPDA) and p-phenylene. It is bonded by a polyimide resin having a diamine (PPD) structure, the average resin thickness of the polyimide resin is 2 μm or more and 16 μm or less, and the three-point bending strength is 0.3 Pa or more. It is a Fe-based nanocrystalline alloy ribbon laminate.
The present invention also provides an antenna magnetic core comprising the Fe-based nanocrystalline alloy ribbon laminate.
In addition, the present invention is an antenna using the antenna magnetic core.

According to the present invention, a polyimide resin is previously applied to the surface of an amorphous alloy ribbon for an Fe-based nanocrystalline alloy ribbon, which has been very difficult in the past, and then slit and cut to a desired size to obtain a plurality of alloys. After laminating the ribbon, after obtaining the laminate by thermocompression bonding in the laminating direction, even the laminate subjected to heat treatment at 500 ° C. or more has high adhesive strength between the alloy ribbons, Can be handled. In addition, a stable quality laminate having small variations in magnetic properties and mechanical strength can be obtained by the above-described steps.
By applying the Fe-based nanocrystalline alloy ribbon laminate to the antenna, the saturation flux density is higher than that of the Co-based amorphous alloy ribbon laminate, and the magnetic permeability and the lower are lower than those of the Fe-based amorphous alloy ribbon laminate. An antenna magnetic core having a loss can be obtained, and an antenna magnetic core excellent for transmission, and further an antenna can be obtained.

Laminate cross-sectional schematic of one embodiment of the present invention The perspective view of the laminated body of one Example of this invention The perspective view of the antenna of one Example of this invention Structural formula of polyimide resin described in Example 1 of the present invention

The inventor of the present invention has obtained a Fe-based nanocrystalline alloy ribbon obtained by heat-treating a laminate of an amorphous alloy ribbon for Fe-based nanocrystalline alloy ribbon coated with a polyimide resin (polyamic acid resin) at 500 ° C. or higher. In the laminate, a combination of an acid anhydride and a diamine constituting a polyimide resin capable of obtaining sufficient mechanical strength is examined.
Polyimide resin has been developed with a design philosophy that raises the decomposition temperature and improves thermal stability and heat resistance by increasing the binding energy of atoms constituting the molecule and increasing the resonance energy between aromatics. Polymer resin. Polyimide resins are inherently rigid polymers due to their molecular structure, but various polyimide resins can be prepared by combining acid anhydrides and diamines.
After applying and drying the polyamic acid solution which is a precursor of the polyimide resin, a dehydration condensation reaction (imidization reaction) occurs by heat treatment at 200 ° C. or higher to become a polyimide resin.

Acid anhydrides and diamines, both of which are composed of a single phenyl group and bonded at the para position of the phenyl group, such as acid anhydrides pyromellitic anhydride (PMDA) and p-phenylenediamine (PPD) (comparison) In Example 1), there are few sites that can rotate in the molecule, and the molecule is very linear and rigid, so that it has high heat resistance, but has a characteristic that it hardly shows flexibility even at high temperatures.
On the other hand, acid anhydrides and diamines both have two phenyl groups and have a structure with oxygen between the phenyl groups, and the two phenyl groups of the acid anhydride are bonded at the meta position, for example, benzophenone tetracarboxylic Since acid dianhydride (BTDA) and 4,4′-oxydianiline (ODA) (Comparative Example 10) are easy to rotate within the molecule, they are sufficiently flexible at high temperatures, and the resin films Easy to thermocompression. However, the heat resistance is inferior to the combination of pyromellitic anhydride (PMDA) and p-phenylenediamine (PPD).

The composition of the Fe-based nanocrystalline alloy ribbon is represented by the general formula: (Fe _1-a M _a ) _100-xyz-α A _x Si _y B _z M ′ _α (atomic%), M is at least one element selected from Co and Ni, A is at least one element selected from Cu and Au, and M ′ is selected from Nb, W, Ta, Zr, Hf, Ti, V and Mo A, x, y, z, and α are 0 ≦ a ≦ 0.5, 0.1 ≦ x ≦ 3, 0 ≦ y ≦ 30, 0 ≦ z ≦ 25, respectively. 5 ≦ y + z ≦ 30 and 0.1 ≦ α ≦ 30. After the heat treatment at 500 ° C. or higher, a microcrystalline structure having an average crystal grain size of 100 nm or less is formed.
The heat treatment temperature is set according to the composition of the alloy ribbon and the desired magnetic properties, but the preferred heat treatment temperature is 500 ° C. or higher and 560 ° C. or lower.

The Fe-based nanocrystalline alloy ribbon is obtained by heat-treating the Fe-based amorphous alloy ribbon produced by rapidly solidifying a molten Fe-based alloy material by a single roll method or the like by the heat treatment at 500 ° C. or more. Later, in order to stably obtain an amorphous state, the thickness of the ribbon is preferably 50 μm or less. On the other hand, the thickness of the ribbon is preferably 10 μm or more in order to ensure the strength when handling the ribbon.
The number of layers of the laminate is determined by the desired magnetic properties, but it is preferable that the number of layers that can be expected as the laminate is 5 or more, more preferably 10 or more. As will be described later, the laminate is produced by thermocompression bonding, but 100 layers or less are preferable, and 60 layers or less are more preferable in order to ensure the uniformity and stability of pressure application to each layer.

As the solvent, N-methylpyrrolidone (NMP) alone may be used, or N, N-dimethylacetamide (DMAc) may be used. NMP and DMAc have good wettability with the alloy ribbon surface, can form a coating film with good adhesion, and no defects.
As the apparatus for applying the polyamic acid solution, a system using a bar coater that can simultaneously apply to a plurality of amorphous alloy ribbons and can relatively increase the coating thickness is preferable.

The thickness of the resin after coating and drying can be obtained by adjusting the mixing ratio of the resin and the solvent, that is, by adjusting the solid content ratio of the resin. Further, by selecting the number of bars used in the bar coater, the thickness can be changed by changing the scraping amount of the resin solution.
Moreover, it is preferable that the thickness of the resin after coating and drying is equal to or greater than the thickness at which the alloy ribbons can be stably thermocompression bonded. If the resin thickness after coating and drying is 1 μm (2 μm between adjacent alloy ribbons) or more, even if the ribbon surface is uneven, the resin surface can be smooth, and the adhesive strength between the alloy ribbons can be increased. It can be secured stably over the entire adhesive surface. In order to secure the adhesive force more stably, the thickness of the resin after coating and drying is preferably 2 μm (4 μm between adjacent alloy ribbons) or more.
On the other hand, in order to suppress interfacial peeling due to the difference in thermal expansion coefficient between the alloy ribbon and the resin, the thickness is preferably 8 μm (16 μm between adjacent alloy ribbons) or less.
The average value of the polyimide resin thickness of the laminated body is the thickness Tm in the lamination direction of the laminated body measured with a micrometer, and the total thickness Ta of the alloy ribbon (the thickness Ta of the alloy ribbon) is determined from the measured value. X is the value obtained by dividing the value obtained by subtracting the number of laminations m) by the number of laminations of alloy ribbons m-1. That is, the average value of the polyimide resin thickness of the laminate is a value represented by (Tm−Ta × m) / (m−1).
Three-point bending strength is evaluated by applying a polyimide resin (polyamic acid resin) with a desired thickness on both sides of an amorphous alloy ribbon for Fe-based nanocrystalline alloy ribbon, laminating, thermocompression bonding, and in nitrogen The laminated body heat-treated at 550 ° C. is placed on a support rod having an 8 mm span, a load is applied to the center portion, the load at which the laminated body is broken is measured, and the strength in the laminated body unit cross-sectional area is calculated.

The thermocompression bonding temperature is preferably higher in order for the polyimide resin surfaces applied to the alloy ribbon to be sufficiently bonded to each other, but since it is usually performed in an air atmosphere from the workability, in order to suppress the oxidative decomposition reaction of the polyimide resin 450 degrees C or less is preferable. Furthermore, 430 degrees C or less is preferable from workability | operativity of heating / cooling.
Moreover, at the time of thermocompression bonding, as described above, an imidization reaction from polyamic acid to a polyimide resin occurs. In order for the imidization reaction to occur sufficiently, a temperature of 300 ° C. or higher is preferable.
The pressure for thermocompression bonding is preferably 50 MPa or more so that the entire surface of the alloy ribbon is sufficiently adhered. Furthermore, 100 MPa or more is more preferable in order to suppress variations among a large number of laminates. The thermocompression bonding is usually performed in a state in which a large number of alloy ribbons are aligned in a jig in order to suppress misalignment of the laminated body. For this reason, the press member of the press device is pressured only on the portion that contacts the jig, and therefore, depending on the pressure resistance of the press member, there is a risk that only the contact portion may be deformed. Is preferably 300 MPa or less, more preferably 200 MPa or less.
Moreover, in the Example mentioned later, although the laminated body is thermocompression-bonded one by one, the resin thin film by which resin was apply | coated to both surfaces (one side in the outermost surface of a laminated body) is continuously crimped | bonded with a heating roll, Then, it may be a step of cutting to obtain individual laminates.

  The heat treatment atmosphere is preferably a nitrogen atmosphere in order to suppress the oxidation reaction of the polyimide resin, and the oxygen concentration in the atmosphere is preferably 500 ppm or less. More preferably, it is 350 ppm or less. In consideration of productivity, the oxygen concentration is preferably 10 ppm or more.

The present invention is a laminate in which a plurality of Fe-based nanocrystalline alloy ribbons are laminated, and the adjacent Fe-based nanocrystalline alloy ribbons are biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PPD). ), Which is bonded by a polyimide resin having a structure of (2), the average value of the resin thickness of the polyimide resin is 2 μm or more and 16 μm or less, and the three-point bending strength is 0.3 Pa or more. It is a crystalline alloy ribbon laminate.
The present invention also provides an antenna magnetic core comprising the Fe-based nanocrystalline alloy ribbon laminate.
In addition, the present invention is an antenna using the antenna magnetic core.

Hereinafter, the present invention will be described in detail based on examples.
In examining the combination of acid anhydride and diamine satisfying both the thermocompression bonding property between resin films at 420 ° C. and the strength of the laminate after heat treatment at 550 ° C. The diamine is a combination of para and meta positions, specifically, pyromellitic anhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), benzophenonetetracarboxylic dianhydride as acid anhydrides. Three types of products (BTDA), p-phenylenediamine (PPD), m-phenylenediamine (MPD), 4,4′-oxydianiline (ODA), 3,3′-oxydianiline (MODA) as diamines The 12 types listed in Table 1 were combined, and the thermocompression bonding property between the resin films at 420 ° C. and 550 ° C. Focusing on strength by 3 point bending test of the laminate after the heat treatment was evaluated.

The 12 types of polyamic acid NMP solutions were prepared, applied to both sides of the surface of the amorphous alloy ribbon for the Fe-based nanocrystalline alloy ribbon, dried, then cut to the desired size, and 20 alloy ribbons were obtained. Thermocompression bonding was performed at 420 ° C.
As described in Examples described later, first, it was evaluated whether the thermocompression-bonded laminate was bonded with sufficient adhesive force. Even when bending stress was applied to the laminate after thermocompression bonding, the case where the layers were adhered was evaluated as “◯”, and the case where peeling between the layers was observed was evaluated as “x”.
The thermocompression-bonded laminate was heat treated in a nitrogen atmosphere at 550 ° C. for 1 hour to evaluate the adhesive strength between the alloy ribbons. Similarly to the above, even when bending stress was applied to the laminate after thermocompression bonding, the case where the layers were adhered was evaluated as “◯”, and the case where peeling between the layers was observed was evaluated as “x”.

Example 1
As the amorphous alloy ribbon for the Fe-based nanocrystalline alloy ribbon, a strip shape having a composition of Fe ₇₄ Cu ₁ Nb ₃ Si _15.5 B _6.5 (atomic%) having a width of 20 mm, a thickness of 18 μm, and a length of 300 mm was used.
As the polyamic acid solution, among the combinations shown in Table 1, an NMP solution containing 18% by mass of polyamic acid in which the acid anhydride is biphenyltetracarboxylic dianhydride (BPDA) and the diamine is p-phenylenediamine (PPD) is used. Produced.
Next, using a bar coater coating device manufactured by Matsuo Sangyo Co., Ltd. The polyamic acid solution was applied to the strip-shaped amorphous alloy ribbon using 3 bars. The coating speed was about 30 mm / s. Then, it dried on the hotplate with a temperature of 150 degreeC. Next, the polyamic acid solution was applied to the surface opposite to the coated surface and dried.
Thus, an amorphous alloy ribbon for an Fe-based nanocrystalline alloy ribbon obtained by applying and drying a plurality of polyamic acid solutions was obtained. When the thickness of the polyamic acid after drying was confirmed with a micrometer, the average coating thickness of both surfaces was 7 μm, and the coating thickness variation was within 1 μm.
The alloy ribbon having a width of 20 mm to which the polyamic acid solution was applied and dried was cut every 6 mm, cut into a 20 mm × 6 mm rectangular shape, and 20 sheets were stacked on a 3 mm-thick stainless steel stacking jig. Prepare an amorphous alloy ribbon with polyamic acid applied to only one side in advance on the top layer of the laminated alloy ribbon, and apply the coated surface to the adjacent amorphous alloy ribbon side. Stacked to the outside.
Twenty sheets of amorphous alloy ribbons were taken as one level, and 5 levels were stacked on the stacking jig.
The stacking jig in which the five layers of the laminate are set is set in a pot press set at a temperature of 420 ° C. After setting, the temperature decreases due to the heat capacity of the stacking jig, but the temperature of the upper and lower presses is again displayed at 420 ° C. Then, the pressure was maintained at 100 MPa for 10 minutes. Thereafter, the stacking jig was taken out and cooled to room temperature. From the lamination jig, 5 thermocompression-bonded laminates were obtained. No change in the coating thickness of the polyamic acid was observed even by thermocompression bonding.
Even when the laminate was bent with a radius of curvature of 100 mm, no peeled portion was observed.
The thermocompression-bonded laminate was heat-treated at 550 ° C. for 1 hour in a nitrogen atmosphere batch furnace. The oxygen concentration at this time was 300 ppm.
Even when the five heat-treated laminates were bent with a radius of curvature of 100 mm, no peeled portion was observed. Further, a three-point bending test was performed, and the three-point bending strength was in the range of 0.3 to 0.6 Pa. FIG. 1 shows a schematic diagram of a cross section in the short-side direction of the laminate. 1 is an Fe-based nanocrystalline alloy ribbon, and 2 is a polyimide resin. FIG. 2 shows a perspective view of the laminate 3.
FIG. 4 shows the structural formula of the polyimide resin in this example.

(Comparative Example 1)
As a polyamic acid solution, among the combinations shown in Table 1, an NMP solution containing 18% by mass of polyamic acid in which acid anhydride was pyromellitic acid (PMDA) and diamine was p-phenylenediamine (PPD) was prepared.
Other conditions were produced in the same manner as in Example 1, and thermocompression bonding of the laminate was attempted by holding at a temperature of 420 ° C. and a pressure of 100 MPa for 10 minutes, but the alloy ribbons were not bonded to each other in all laminates. .

(Comparative Example 2)
As a polyamic acid solution, among the combinations shown in Table 1, an NMP solution containing 18% by mass of a polyamic acid having an acid anhydride of pyromellitic acid (PMDA) and a diamine of m-phenylenediamine (MPD) was prepared.
Other conditions were produced in the same manner as in Example 1, and thermocompression bonding of the laminate was attempted by holding at a temperature of 420 ° C. and a pressure of 100 MPa for 10 minutes, but the alloy ribbons were not bonded to each other in all laminates. .

(Comparative Examples 3, 4, 6, 7, 8, 9, 10, 11)
As the polyamic acid solution, acid anhydride is pyromellitic anhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), benzophenonetetracarboxylic dianhydride (BTDA), diamine is p-phenylenediamine (PPD), m- NMP solution 8 of the combination shown in Table 1 using phenylenediamine (MPD), 4,4′-oxydianiline (ODA), 3,3′-oxydianiline (MODA) and having a polyamic acid of 18% by mass Kinds were made.
Using the respective polyamic acid solutions, other conditions were prepared in the same manner as in Example 1. As a result of thermocompression bonding of the laminate at a temperature of 420 ° C. and a pressure of 100 MPa for 10 minutes, the laminate was bent at a radius of curvature of 100 mm. Even if it was made to peel, the peeling part was not observed.
However, when the laminate was heat-treated at 550 ° C. for 1 hour, all the laminates were separated at the interface between the polyimide resin and the alloy ribbon and separated into 3 to 5 pieces.

(Comparative Example 5)
As the polyamic acid solution, among the combinations shown in Table 1, an NMP solution containing 18% by mass of polyamic acid in which acid anhydride is biphenyltetracarboxylic dianhydride (BPDA) and diamine is M-phenylenediamine (MPD). Was made.
Using the respective polyamic acid solutions, other conditions were prepared in the same manner as in Example 1. As a result of thermocompression bonding of the laminate at a temperature of 420 ° C. and a pressure of 100 MPa for 10 minutes, the laminate was bent at a radius of curvature of 100 mm. Even if it was made to peel, the peeling part was not observed.
When the laminated body was heat-treated at 550 ° C. for 1 hour, no peeled portion was observed in all the laminated bodies even when the curvature radius was bent 100 mm.
Next, when a three-point bending test was performed, the three-point bending strength was in the range of 0.1 to 0.2 Pa.

(Example 2)
In Example 1, after applying and drying the polyamic acid, the average coating thickness of both surfaces was changed to 2 μm, and a thermocompression-bonded laminate was produced.
Even when the laminate was bent with a radius of curvature of 100 mm, no peeled portion was observed.
Even when the heat-pressed laminate was subjected to the same heat treatment as in Example 1 and the heat-treated laminate was bent with a radius of curvature of 100 mm, no peeled portion was observed in all the laminates. Further, a three-point bending test was performed, and the three-point bending strength was in the range of 0.3 to 0.6 Pa.

(Comparative Example 12)
In Example 1, after the polyamic acid was applied and dried, the average coating thickness of both surfaces was changed to 1.6 μm, and other conditions were prepared in the same manner as in Example 1, and the thermocompression bonding of the laminate was performed at a temperature of 420. Attempts were made by holding at 10 ° C. and a pressure of 100 MPa for 10 minutes, but the alloy ribbons were not adhered to each other in all laminates.

(Example 3),
In Example 1, after applying and drying the polyamic acid, the average coating thickness of both surfaces was changed to 16 μm, and a thermocompression-bonded laminate was produced.
Even when the laminate was bent with a radius of curvature of 100 mm, no peeled portion was observed.
The heat-pressed laminate was subjected to the same heat treatment as in Example 1, and the heat-treated laminate was bent at a radius of curvature of 100 mm, but no peeled portion was observed in all the laminates. Further, when a three-point bending test was performed, the three-point bending strength was in the range of 0.4 to 0.5 Pa.

(Comparative Example 13)
In Example 1, after the polyamic acid was applied and dried, the average coating thickness of both surfaces was changed to 17 μm, and a thermocompression-bonded laminate was produced.
Even when the laminate was bent with a radius of curvature of 100 mm, no peeled portion was observed.
However, the thermocompression-bonded laminate was subjected to the same heat treatment as in Example 1, and the laminate after the heat treatment was bent at a radius of curvature of 100 mm. As a result, the laminate was peeled off at the interface between the polyimide resin and the alloy ribbon. A portion was observed.

Example 4
As shown in FIG. 3, a 20 mm wide alloy ribbon obtained by applying and drying the polyamic acid solution described in Example 1 was slit to a width of 8 mm, and further cut to a length of 50 mm. A laminated body was obtained by laminating 40 layers of 8 mm rectangular alloy ribbons by the method described in Example 1 except that the size and the number of laminated layers were different. The thickness was about 0.8 mm.
A coil was formed by winding 80 turns using a UEW wire having a diameter of 0.23 mm as a conducting wire in the laminate. The DC resistance of the obtained coil was 0.8Ω, and the inductance was about 200 μH at a frequency of 134.2 kHz.
A matching capacitor was connected in series to one end of the conducting wire (coil), and the resonance frequency was adjusted to 134.2 kHz to obtain a transmitting antenna. When an alternating current of 134.2 kHz 0.5 App was applied to this antenna and the electric field strength was measured with an LF probe at a position 3 m away from the transmitting antenna, it was 93.9 to 97.0 dBμV / m. It was confirmed that the function was sufficiently satisfied.

1 Amorphous alloy ribbon 2 Polyimide resin 3 Laminate 4 Conductor 5 Antenna

Claims (3)

A laminated body in which a plurality of Fe-based nanocrystalline alloy ribbons are laminated, and the adjacent Fe-based nanocrystalline alloy ribbons have a structure of biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PPD). Fe-based nanocrystalline alloy thin film characterized in that the average value of the resin thickness of the polyimide resin is 2 μm or more and 16 μm or less, and the three-point bending strength is 0.3 Pa or more. Band laminate. An antenna magnetic core comprising the Fe-based nanocrystalline alloy ribbon laminate according to claim 1. An antenna using an antenna magnetic core comprising the Fe-based nanocrystalline alloy ribbon laminate according to claim 2.

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