WO2007013436A1

WO2007013436A1 - Soft magnetic material

Info

Publication number: WO2007013436A1
Application number: PCT/JP2006/314637
Authority: WO
Inventors: Keisuke Aramaki; Satoru Sugita
Original assignee: Sony Chemical & Information Device Corporation
Priority date: 2005-07-26
Filing date: 2006-07-25
Publication date: 2007-02-01
Also published as: TWI482181B; TW200731299A; JP4811607B2; TW201434058A; TWI484508B; TWI512768B; JPWO2007013436A1

Abstract

Disclosed is a soft magnetic material whose specific gravity is increased by cross-linking a binder resin while densely orienting a soft magnetic powder in the binder resin and which shows a little change in dimension and magnetic properties at a high temperature or under high temperature and high humidity. A soft magnetic material comprising at least a cross-linked polyester resin and a flat, soft magnetic powder dispersed in the resin, wherein the soft magnetic powder is contained in an amount of 450 to 550% by weight, the resin is contained in an amount of 80 to 120% by weight, and the magnetic powder is oriented approximately in the in-plane direction.

Description

Specification

Soft magnetic material

Technical field

[0001] The present invention relates to a magnetic material that reduces the influence of nearby metals in order to improve communication using a 13.56 MHz frequency in a mobile terminal having a so-called RFID (Radio Frequency Identification) function. The present invention relates to a magnetic sheet and a manufacturing method thereof. The present invention also relates to a magnetic material for suppressing electromagnetic interference caused by interference of unnecessary electromagnetic waves in electronic equipment.

Background art

[0002] In recent years, mopile terminals such as mobile phones having an IC tag function for wireless communication in the 13.56 MHz band have been put into practical use. In this case, there is an application in which an antenna coil for transmission / reception is placed in the case of a small and thin mobile phone. When the antenna coil is in close proximity, the magnetic field lines generated around the antenna coil during transmission and reception run parallel to the metal surface, generating eddy currents on the metal surface, and the magnetic field used for communication is greatly attenuated. It has been confirmed that the communication distance is significantly shortened. As one of the countermeasures, it has been proposed to arrange a magnetic material parallel to the plane of the antenna coil, increase the antenna coil inductance, and improve the communication distance (Patent Document 1). ).

[0003] In addition, in recent years, electronic devices such as home electric appliances such as televisions, mobile communication devices such as personal computers and mobile phones, and medical devices have been widely used and released from the above electronic devices. Unwanted electromagnetic waves may cause other electronic devices to malfunction. Therefore, in such electronic devices, magnetic materials are used for the purpose of suppressing electromagnetic interference in order to remove unnecessary electromagnetic waves.

By the way, in a mobile communication terminal, an antenna module in which a soft magnetic sheet containing magnetic powder is disposed between an antenna coil and a shield plate is used in order to improve communication characteristics. In this case, the thickness of the mobile communication terminal becomes thinner as the mobile communication terminal becomes smaller and thinner. A soft magnetic sheet having a high magnetic permeability is required. On the other hand, for antenna modules built in electronic devices such as communication mobile terminals, there is a demand that contradicts the demand for thinner modules, that is, that the communication distance is further improved. Therefore, communication portable terminals and the like are required to satisfy these requirements simultaneously.

[0005] The size of the magnetic powder constituting the magnetic sheet used in the veg antenna module that meets the above-described requirements has been studied. For example, by increasing the particle size of the magnetic powder to be used in the antenna module, it is possible to increase the permeability of the magnetic sheet and increase the communication distance of the antenna module. However, when the particle size of the magnetic powder is increased, the power loss due to the overcurrent loss of the magnetic sheet becomes significant, resulting in a problem that the IC read voltage is lowered and the communication distance is shortened.

[0006] For this reason, the magnetic powder to be used for balancing the above-mentioned conflicting demands with "increasing the magnetic permeability of the magnetic sheet" and "decreasing overcurrent loss". Attempts have been made to increase the size of these powders and to reduce the amount of magnetic powder used (mixing ratio). However, in order to increase the magnetic permeability, it is necessary to increase the specific gravity of the magnetic sheet. However, if the amount of magnetic powder used is reduced, the specific gravity of the magnetic sheet cannot be increased. Therefore, in order to ensure the necessary magnetic properties, the thickness of the magnetic sheet must be increased, and the thickness of the antenna module must be increased! /.

[0007] Therefore, as a magnetic sheet intended to solve the above problems, a flat soft magnetic powder, chlorinated polyethylene as a Noinder resin, and a solvent are mixed, and the obtained soft magnetic coating is applied to a release substrate. A soft magnetic sheet has been proposed in which flat soft magnetic powder is oriented in the in-plane direction by peeling off from the release substrate after being coated on the substrate and drying, followed by hot pressing at a temperature of 180 ° C and a pressure of 30 MPa. (Patent Document 2).

[0008] By the way, when trying to increase the magnetic permeability of such a soft magnetic sheet, if the glass transition point Tg is extremely low as compared to room temperature, the soft magnetic sheet itself is soft. Since the point is lowered, the soft magnetic powder can be efficiently oriented by compressing with a laminator or a hot press device while applying heat above the soft saddle point, and the specific gravity can be increased. On the other hand, such soft magnetic sheets are further required to exhibit excellent dimensional stability and magnetic property stability over a long period of time. This is the thickness of the magnetic sheet This is because in the antenna module using this, the relative positional relationship between the antenna coil and the shield plate and the magnetic characteristics of the soft magnetic sheet itself change, resulting in a problem that the communication characteristics change. . For this reason, when producing a soft magnetic sheet, an attempt has been made to use a curing agent in order to crosslink the polymer binder. Patent Document 1: Japanese Patent Laid-Open No. 2000-48152

Patent Document 2: Japanese Patent Laid-Open No. 2002-158488

Disclosure of the invention

Problems to be solved by the invention

[0009] However, when the solvent is dried after the soft magnetic coating material is applied on the release substrate, the curing agent and the binder resin react to start the curing reaction. When compression is carried out, the curing reaction proceeds further, and the resin is wound in a state where it is compressed to a certain extent and is cured with air contained therein. Therefore, the specific gravity may not be increased to the intended value. In addition, if the glass transition point Tg of the binder resin is too low, the compressed soft magnetic sheet loosens and returns to its thickness when the soft magnetic sheet is left in a high temperature or high temperature and high humidity environment. There is.

[0010] The present invention has been proposed in order to solve the above-mentioned problems, and the soft magnetic powder is crosslinked in a densely oriented state in the binder resin to increase the specific gravity, thereby increasing the temperature or temperature. In a high humidity environment! / Small changes in dimensions and magnetic properties! It is an object of the present invention to provide a soft magnetic material, a manufacturing method thereof, and an electronic device using the magnetic material of the present invention, such as an antenna module or a portable communication terminal.

Means for solving the problem

[0011] The inventors of the present invention achieve the above object by using a soft magnetic powder having a flat shape, using a polyester-based resin as the binder resin, and crosslinking the binder resin. The present inventors have found that the present invention can be accomplished and have completed the present invention.

That is, the present invention provides a soft magnetic material in which at least a flat soft magnetic powder is dispersed in a cross-linked polyester-based resin.

[0013] In addition, the present invention provides an antenna module comprising the above-described soft magnetic material, for example, an antenna module characterized in that the soft magnetic material is laminated on a support body on which an antenna coil is formed. And a mobile communication terminal including the antenna module.

[0014] Further, the present invention is a method for producing the above-mentioned soft magnetic material in sheet form, comprising a soft magnetic composition comprising at least a flat soft magnetic powder, a polyester-based rosin, a crosslinking agent, and a solvent. A method for producing a soft magnetic material is provided in which after coating on a release substrate, drying is performed at a temperature at which a crosslinking reaction does not substantially occur, and compression is performed at a temperature at which the crosslinking reaction occurs. In this case, after drying at a temperature at which crosslinking reaction does not substantially occur, it is preferable to compress at a temperature at which crosslinking reaction does not substantially occur before compression at a temperature at which crosslinking reaction occurs.

[0015] Further, the present invention provides a crosslinking reaction substantially after applying a soft magnetic composition comprising at least a flat soft magnetic powder, a polyester-based resin, a crosslinking agent, and a solvent on a release substrate. By drying at a temperature that does not occur and removing the release substrate repeatedly, at least two dry sheets of the soft magnetic composition are obtained, and the at least two dry sheets are laminated, and a temperature at which a bridge reaction occurs. A method for producing a laminated soft magnetic sheet is provided. In this case, after laminating at least two dry sheets, it is preferable to compress at a temperature at which crosslinking reaction does not substantially occur before compression at a temperature at which crosslinking reaction occurs.

The invention's effect

In the soft magnetic material of the present invention, the flat soft magnetic powder is dispersed while being densely oriented in the polyester-based resin that is the binder resin, and in this state, the polyester-based resin is crosslinked. Therefore, it has a large specific gravity and exhibits good magnetic properties. In addition, it is a highly reliable soft magnetic material with small dimensional change even in a high temperature environment or a high temperature and high humidity environment. Further, when a phosphorus-containing polyester-based resin is used as the polyester-based resin, the acid value can be increased and excellent adhesion to metal can be exhibited, so that the specific gravity can be increased. Therefore, the soft magnetic material of the present invention has a small dimensional change after an environmental test and a small change in magnetic characteristics. Therefore, if the sheet is formed and applied to an antenna module, the communication distance can be improved. It becomes. In addition, the antenna module can be made thinner and lighter. Furthermore, even if such an antenna module is stored in a metal casing, the deterioration of the communication performance is suppressed, and the initial communication distance is maintained. Therefore, the soft magnetic material of the present invention is useful for RFID applications and radio wave absorbers, and can be used as noise electromagnetic wave absorbers for electronic devices such as portable digital cameras. BEST MODE FOR CARRYING OUT THE INVENTION

[0017] The soft magnetic material of the present invention is a soft magnetic material in which at least flat soft magnetic powder is dispersed in a crosslinked polyester-based resin, and is preferably a sheet-shaped soft magnetic material.

In the soft magnetic material of the present invention, first, flat soft magnetic powder is used as soft magnetic powder. Therefore, high magnetic permeability and high specific gravity can be realized by arranging flat soft magnetic materials in a two-dimensional in-plane direction.

[0019] As the raw material of the flat soft magnetic powder, any soft magnetic alloy can be used, for example, magnetic stainless steel ^ 6—0: —8-31 alloy), Sendust ^ 6-31—8-1 alloy) , Permalloy (Fe—Ni alloy), copper (Fe—Cu—Si alloy), Fe—Si alloy, Fe—Si—B (—Cu—Nb) alloy, Fe—Ni—Cr—Si alloy, Fe-Si-Cr alloy, Fe-Si-Al-Ni-Cr alloy, ferrite and the like can be mentioned. Among these, Fe-Si-A1 alloy or Fe-Si-Cr-Ni alloy can be preferably used because of its magnetic properties.

[0020] For these soft magnetic alloys, the real part (permeability) μ 'of the complex relative permeability is relatively large (preferably 35 or more), and the imaginary part (magnetic loss) μ "of the complex relative permeability is μ" It is preferable to use a relatively small value (preferably 1 or less) and a Q value that is relatively large (preferably 28 or more), that is, the larger the μ ′ value, the more the RFID communication antenna coil magnetic flux corresponds. The antenna sensitivity is improved because it easily passes through the antenna coil. The smaller the value of the imaginary part μ ", the smaller the power loss due to the eddy current loss of the magnetic material, the lower the IC calling voltage and the shorter the communication distance. I won't let you. Also, the higher the Q value, the higher the selectivity of the resonance frequency and the better the sensitivity. The values of and fluctuate depending on the composition of the magnetic alloy and the operating frequency, but in the soft magnetic material of the present invention, the permeability μ ′ is preferably 35 or more. When the permeability μ ′ is 35 or more, the communication distance when mounted on a portable mono electronic device is: Q 0 _mm or more, and convenience is improved. The specific gravity of the soft magnetic material is desirably 3.0 or more. More preferably, it is 3.20 or more. By increasing the specific gravity of the soft magnetic material, the air contained in the soft magnetic material is reduced and the flame retardancy can be improved.

[0021] Further, as the flat soft magnetic alloy, it is preferable to use a material having a relatively large resistance in order to reduce the value of "in order to reduce eddy current loss. Resistance can be increased by changing the composition. For example, in the case of an Fe—Si—Cr alloy, the Si ratio is preferably 9 to 15 wt.%.

[0022] As the flat soft magnetic powder used in the present invention, a soft magnetic powder having a flat shape is used. Preferably, the average particle diameter is 3.5 to 90 / ζ πι, and the average thickness is 0.3 to 2. 1 ^ m, more preferably the average particle size is 10-50 μm and the average thickness is 0.5-1.5 μm. Therefore, the flatness is preferably set to 8 to 24, more preferably 15 to 22. In order to make the size of the flat soft magnetic powder uniform, classification may be performed using a sieve or the like as necessary. In order to increase the magnetic permeability of the soft magnetic material, the particle size of the flat soft magnetic powder is increased to reduce the spacing between the particles, and the aspect ratio of the flat soft magnetic powder is increased to increase the soft magnetic material. It is effective to reduce the influence of the demagnetizing field.

[0023] The tap density CFIS K 5101) and the specific surface area (BET method) of the flat soft magnetic powder used in the present invention are inversely proportional to each other, but only the value of increasing the non-surface area is desired to increase. Since the value of 〃 which does not tend to increase, those numerical ranges are set to a preferable range. Specifically, the tap density is preferably set to 0.55 to: L 45 gZml, more preferably 0.65 to L0g / ml, while the specific surface area is preferably set to 0.40-1.20 m ² . Zg, more preferably from 0.65 to: L 00m ² Zg.

[0024] Further, as the flat soft magnetic powder, a powder whose surface is covered with an insulating layer can be used. By using flat soft magnetic powder coated with an insulating layer, μ 'of flat soft magnetic material is reduced and Q is improved, so the communication distance of mopile terminals with RFID (Radio Frequency Identification) function is improved. . As a method for forming the insulating layer, there are a method of coating with a resin, a method of forming an oxide film by heating, and a method of forming an oxide film on a soft magnetic powder by a thin film forming technique such as sputtering. Al O, Oxide film

twenty three

SiO or the like can be used. Examples of the resin to be coated include attalates and esthetics.

2

Lubricants such as rubbers, urethanes and epoxies can be used.

The flat soft magnetic material used in the present invention does not necessarily use flat soft magnetic powder coated with an insulating layer, but at least about 5% by weight of the flat soft magnetic powder used is covered with an insulating layer. It is preferable to use soft magnetic powder.

[0026] In the present invention, as the soft soft magnetic powder, for example, a silane coupling agent or the like is used. You may use soft magnetic powder that has been coupled with a coupling agent. By using the soft magnetic powder that has been subjected to force-pulling treatment, the effect of reinforcing the interface between the flat soft magnetic powder and the polyester-based resin, which is a binder resin, can be enhanced, and the specific gravity and corrosion resistance can be improved. As the coupling agent, for example, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropynolemethyljetoxysilane and the like can be used. The coupling treatment may be performed on the soft magnetic powder in advance, or may be mixed at the same time when the flat soft magnetic powder and the binder resin are mixed. As a result, the coupling treatment is performed. It may be performed.

[0027] If the amount of the flat soft magnetic powder used in the soft magnetic material of the present invention is too small, the intended magnetic properties cannot be obtained, and if it is too large, the amount of binder resin is relatively reduced and the moldability is lowered. since, preferably 400 to 600 weight ^_0/0, more preferably 450 to 550 weight ^_0/0

[0028] In the present invention, as a Noinder resin, it has good strength and low hygroscopicity, and can maintain a practical strength even if it is a sheet. Polyester-based resin that can hold a large amount of is used. The number average molecular weight of such a polyester-based resin is such that if the number average molecular weight is too small, the mechanical strength of the resulting sheet-like soft magnetic material will be insufficient, and if it is too large, the resulting sheet-like soft magnetic material will be insufficient. Preferred <is 3000 to 100,000, more preferred <is 8000 to 50000, and particularly preferred <is 1000 to 50000 because the magnetic material becomes hard and brittle.

[0029] Further, if the glass transition point of the polyester-based resin, which is a binder resin, is too low, the elastic modulus at high temperature decreases, resulting in insufficient adhesion between soft magnetic powders. The soft magnetic material in the form of a sheet becomes hard, the handleability at room temperature decreases, and the softening point tends to be too high, so that the orientation of the soft magnetic powder may not proceed smoothly. Therefore, the glass transition point is preferably 20 ° C to 40 ° C, more preferably — 20 ° C to 10 ° C, and the soft spot is preferably 130 ° C or less, more preferably 100 ° C or less. It is.

[0030] When the hydroxyl value CFIS K 1557) of the polyester resin, which is a binder resin, is too small, the crosslinking is insufficient and the mechanical strength is insufficient, and the thickness change of the soft magnetic material is large. If it is too large, the hygroscopicity may be too high, so 4.5 mgKOH / g to 15 mgKOH / g, more preferably 4.5 mgKOH / g to 8 mgKO.

HZg.

[0031] If the acid value (titration method) of the polyester-based rosin, which is a Noinder rosin, is too small, the adhesion between the magnetic powder and the resin is too poor. mg KOHZg to 4.0 mgKOHZg ゝ more preferably 2 mgKOHZg to 3 mgKOHZg or less.

[0032] In the present invention, in the case of imparting flame retardancy to a soft magnetic material, a polyester resin having flame retardancy can be used. It is preferable to use a polyester resin containing phosphorus. Phosphorus-added polyester resin is a non-halogen flame retardant having a phosphoric acid residue in the molecule and exhibits high flame resistance (UL94 V-0). Also, unlike the conventional case where a large amount of flame retardant is added due to the flame retardant, the decrease in permeability after the environmental test is small.

[0033] Examples of the phosphorus-containing polyester-based resin include phosphorus-modified polyester copolymers. The phosphorus-modified polyester copolymer is obtained by introducing a phosphorus component into the main skeleton of the polyester copolymer, and is obtained by copolymerizing a polyester component and a phosphorus component. Here, as the polyester component, ethylene glycol and a polymer compound formed with terephthalic acid, naphthalenecarboxylic acid, adipic acid, sebacic acid or isophthalic acid, 1,4 butanediol and terephthalic acid, adipic acid or A polymer compound formed from sebacic acid, a polymer compound formed from 1,6 hexanediol, and adipic acid, sebacic acid or isophthalic acid can be used. As the phosphorus component, phosphonate type polyols, phosphate type polyols, bull phosphonates, aryl phosphonates and the like can be used. Thus, the polyester copolymer having the phosphorus component introduced into the main skeleton is higher than that obtained by simply mixing and dispersing the phosphorus component in the polyester, and exhibits flame retardancy.

[0034] The phosphorus content of the polyester-based polyester resin containing phosphorus depends on the type of the main skeleton of the polyester-based resin, the type of phosphorus component (phosphoric acid residue), the type of other components constituting the soft magnetic sheet, etc. Depending on the requirement, it can be determined to satisfy the prescribed flame retardancy. Flammability cannot be realized, and if the amount is too large, the properties of the resin are lowered. Therefore, the content is preferably 3.0 to 10% by weight, more preferably 3 to 6% by weight.

[0035] In the present invention, together with the polyester-based resin as described above, an epoxy resin, a polyester-based resin, an acrylic resin, an aliphatic hydrocarbon resin as long as the effects of the present invention are not impaired. Rosin resin, nylon resin, phenol resin, polyurethane resin, melamine resin, polyamine resin, urea formaldehyde resin, polyisocyanate and epoxy compound and isocyanate compound and imidazole compound A mixture with a product can be used in combination as a binder resin.

[0036] In the soft magnetic material of the present invention, as described above, the polyester-based resin is crosslinked. This cross-linking is achieved by blending a cross-linking agent when dispersing the soft magnetic powder in the polyester-based rosin and causing a cross-linking reaction between the polyester-based rosin and the cross-linking agent. As such a cross-linking agent, a cross-linking agent conventionally used for the cross-linking reaction of polyester-based resin can be used, and it is particularly preferable to use a block isocyanate as a cross-linking agent. Here, the block isocyanate is a compound in which an isocyanate compound is capped with a blocking agent and an isocyanate group (—NCO) is blocked, and the block isocyanate does not dissociate at room temperature. Although the fat is not crosslinked, when heated to a temperature higher than the dissociation temperature of the block isocyanate, the blocking agent is dissociated, and the polyester-based resin is crosslinked by the activated isocyanate compound. The dissociation temperature of the blocking agent can be selected in the range of 80 ° C to 180 ° C. Specific examples of the block isocyanate include Coronate 2507 (manufactured by Nippon Polyurethane Co., Ltd.).

[0037] Here, the reason for using the block isocyanate is that it is blocked as a crosslinking agent when a sheet-like soft magnetic material is produced by a coating method which is a general film forming technique! When using V / isocyanate, polyester resin and isocyanate react and harden when the solvent is dried, whereas when block isocyanate is used, the block must be heated above the temperature at which the block is released. This is because the reaction does not proceed. In addition, air is taken into the soft magnetic material by drying the solvent, but the reaction between the polyester-based resin and isocyanate does not proceed below the block agent desorption temperature and proceeds slowly after block desorption. The soft magnetic material is fully compressed to eliminate air and the soft magnetic powder is closely oriented This is because the crosslinking reaction can be carried out. In addition, the mechanical strength of the soft magnetic material can be increased by crosslinking, and further, the occurrence of loosening can be suppressed even in a high temperature environment or a high temperature and high humidity environment, and a change in thickness can also be suppressed. By using block isocyanate as a cross-linking agent, the cross-linking reaction is not started unless the dissociation temperature is exceeded, so that the soft magnetic powder is densely oriented by sufficiently compressing at a temperature at which the cross-linking reaction does not start. After that, a sheet-like soft magnetic material having a large specific gravity can be obtained by further compressing and orienting above the dissociation temperature.

[0038] In the present invention, if the dissociation temperature of the block isocyanate is too low, crosslinking starts before the soft magnetic coating material is sufficiently compressed during the production of the soft magnetic material described later, and the specific gravity is increased. If the dissociation temperature is too high, it will be used during the manufacture of the soft magnetic material described later. Since the release substrate may be damaged by heat, it is preferably 100 ° C to 180 ° C, more preferably 120 ° C to 160 ° C. The reaction for cross-linking polyester-based resin is very slow even at room temperature, so if heated to the dissociation temperature and left at room temperature for a long time, the polyester-based resin is completely cross-linked and cured.

[0039] If the proportion of the block isocyanate used is too small, the crosslinking of the polyester-based resin may be insufficient, and the thickness change may be too large. If the amount is too large, the specific gravity of the sheet will not increase. The amount of coconut oil is preferably 0.5% by mass to 10% by mass, more preferably 1% by mass to 8% by mass.

[0040] The crosslinked polyester resin constituting the soft magnetic material of the present invention is obtained by crosslinking the polyester resin described above with a crosslinking agent, and its content in the soft magnetic material. is too small will not become sheet density is high, since if too great is not high, preferably 60 to 150 weight ^_0/0, more preferably 80 to 120 weight ^_0/0.

[0041] In order to ensure sufficient flame retardancy, such as UL94 V-1, for example, in the soft magnetic material of the present invention, heat resistance, physical property degradation, high temperature conditions, Other flame retardants can also be added to the extent that they do not affect the degradability and surface properties.

[0042] The soft magnetic material of the present invention described above uses a polyester-based resin having a relatively low glass transition point Tg as a binder resin, and has a dissociation higher than the glass transition point. Since the block isocyanate showing the temperature is used as a cross-linking agent, the release temperature of the block isocyanate does not exceed so that the flat soft magnetic powder is oriented in the same plane when the soft magnetic material is produced. When heated in this way, it shrinks and the specific gravity and permeability increase. In addition, when heated above the dissociation temperature of block isocyanate, the polyester-based resin is cross-linked, so it is thicker at high temperatures or in high-temperature, high-humidity environments than conventional magnetic sheets that are not cross-linked with polyester-based resin. Small dimensional change such as height. Specifically, the soft magnetic material of the present invention can have a dimensional change of 3% or less after being left in a high temperature environment of 60 ° C. to 95 ° C. Furthermore, the dimensional change after being left under high temperature and high humidity at a temperature of 40 ° C to 90 ° C and a relative humidity of 60 to 95% can be 3% or less. Therefore, the general operating temperature range of magnetic sheets used in electronic devices such as mobile phones and digital cameras is 25 ° C to 85 ° C, and high temperature and high humidity conditions are 60 ° C and 95Rh%. However, the soft magnetic material of the present invention is useful for reducing the dimensional change which becomes a problem on the high temperature side for these evaluations. In addition, since the soft magnetic material of the present invention is cross-linked with polyester-based resin, the mechanical strength of the material itself is increasing, so that a physical impact such as a heat change is applied or the desired shape is obtained. Even when die cutting is performed, there is an advantage that there is no powder fall off from the end surface force of the soft magnetic material.

[0043] The soft magnetic material of the present invention compresses a soft magnetic composition obtained by mixing at least a flat soft magnetic powder, a polyester-based resin and a crosslinking agent according to a conventional method at a temperature at which a crosslinking reaction occurs. Can be manufactured. Here, when compression is performed at a temperature at which the crosslinking reaction occurs, the crosslinking reaction starts to start, and at the same time, while the crosslinking reaction is not sufficiently advanced, the composition is contracted and the flat soft magnetic powder is in the compression direction. Therefore, the specific gravity is increased and the magnetic properties are improved. Furthermore, when the crosslinking reaction proceeds, the entire polyester-based resin is crosslinked, shrinkage is suppressed, and dimensional stability is improved.

By the way, when preparing a soft magnetic composition, if an excessively strong shearing force is applied to the composition, it becomes difficult to maintain the shape of the flat soft magnetic powder, and the flat soft magnetic powder is moved in a certain in-plane direction. Since it must be oriented, it is preferable to increase the fluidity of the soft magnetic composition and set it to a relatively low viscosity. There is also a need to sheet soft magnetic materials. In that case, if the application method is used to form the sheet, the soft magnetic composition Since it is necessary to lower the viscosity, it is preferable to use a soft magnetic composition in combination with a solvent that dissolves the polyester-based resin as the binder resin. As such a solvent, for example, aromatic hydrocarbon compounds such as methyl ethyl ketone, benzene, toluene and xylene, and ketone compounds such as cyclohexanone and methyl isobutyl ketone can be used. However, if the viscosity of the soft magnetic composition is too small, the specific gravity of the sheet-like soft magnetic material tends to be too small, and if it is too large, the application becomes difficult or the coating stripes are formed. is there. Therefore, the amount of the solvent used is preferably such that the solid content in the soft magnetic composition is 50 to 70% by weight.

[0045] The sheet-like soft magnetic material has substantially no cross-linking reaction after a soft magnetic composition formed by mixing at least a flat soft magnetic powder, a polyester-based resin, a cross-linking agent, and a solvent is applied onto a release substrate. It can be produced by drying at a temperature that does not occur and compressing at a temperature at which a crosslinking reaction occurs.

[0046] First, a soft magnetic composition is prepared by mixing at least a flat soft magnetic powder, a polyester-based resin, a crosslinking agent, and a solvent. Specifically, the polyester-based rosin is dissolved in a solvent, and a soft magnetic powder and a crosslinking agent are added and mixed in the solution.

[0047] Next, the soft magnetic composition is applied onto the release substrate. As a coating method, a general coating method such as a coater or a doctor blade method can be employed. At this time, the coating thickness of the soft magnetic composition to be formed can be adjusted to a desired thickness by the coating method. Further, at the time of application, by applying a magnetic field to the applied soft magnetic composition, it becomes possible to orient the flat soft magnetic powder in the in-plane direction of the application and to fill the soft magnetic powder with high density. Moreover, you may perform press operation in order to improve specific gravity.

Here, examples of the release substrate include polyethylene terephthalate, polyethylene naphthalate polyimide, polyphenylene sulfide, polypropylene oxide, polyethylene, polypropylene, polyamide, and the like. The thickness of these base materials can usually be several / zm to several hundred / zm. Moreover, you may apply | coat a well-known release agent to the application | coating surface of the soft magnetic composition of a peeling base material.

[0049] Next, the soft magnetic composition applied to the release substrate is dried at a temperature at which a crosslinking reaction does not substantially occur. When dried at a temperature at which cross-linking reaction occurs, the flat soft magnetic powder is in-plane. This is because it cannot be oriented in the direction and the magnetic properties become insufficient. Here, “substantially does not occur” at a temperature at which cross-linking reaction does not substantially occur means that the cross-linking reaction within a range in which the flat soft magnetic powder can be oriented in the same in-plane direction by a laminator hot press. Is an acceptable meaning. Specifically, when a block isocyanate is used as a cross-linking agent, the “temperature at which the cross-linking reaction does not substantially occur” is a temperature lower than the dissociation temperature of the block isocyanate. On the other hand, the “temperature at which the cross-linking reaction occurs” is a temperature equal to or higher than the dissociation temperature of the block isocyanate.

[0050] Next, the dry sheet of the soft magnetic composition is compressed at a temperature at which a crosslinking reaction occurs. In this case, the flat soft magnetic powder is oriented in the same in-plane direction, and finally the crosslinking reaction is completed. This is a force that requires a certain amount of time before the crosslinking reaction is completed even if the crosslinking reaction is completed at a temperature at which the crosslinking reaction occurs.

[0051] Note that after drying at a temperature at which a crosslinking reaction does not substantially occur, and before compression at a temperature at which the crosslinking reaction occurs, compression may be performed at a temperature at which the crosslinking reaction does not substantially occur. In this case, when compression is performed at a temperature at which a bridge reaction occurs, the flat soft magnetic powder is already oriented in the same in-plane direction, so that only a crosslinking reaction mainly occurs.

[0052] Next, an outline of a method of stacking and manufacturing sheet-like soft magnetic materials will be described.

[0053] First, after applying a soft magnetic composition comprising at least a flat soft magnetic powder, a polyester-based resin and a crosslinking agent on a release substrate, drying is performed at a temperature at which a crosslinking reaction does not substantially occur. Then, by removing the release substrate repeatedly, at least two dry sheets of the soft magnetic composition are obtained.

Next, the at least two dry sheets are laminated and compressed at a temperature at which a crosslinking reaction occurs. In this case, the flat soft magnetic powder is oriented in the same in-plane direction, and finally the crosslinking reaction is completed. In addition, if at least two dry sheets are laminated and then compressed at a temperature at which the crosslinking reaction does not substantially occur before being compressed at a temperature at which the crosslinking reaction occurs, the compression is already performed at a temperature at which the crosslinking reaction occurs. Since the flat soft magnetic powder is oriented in the same in-plane direction, only the crosslinking reaction mainly occurs.

The soft magnetic material of the present invention is useful as a magnetic flux converging body in a RFID system such as a non-contact type IC card or IC tag, or as a general electromagnetic wave absorber. RFID It is useful as a noise electromagnetic wave absorber for electronic devices such as flexible shield materials for mobile phones and portable digital cameras. Therefore, various electronic devices such as video equipment provided with the soft magnetic material of the present invention are also part of the present invention.

[0056] Specifically, the soft magnetic material of the present invention can be preferably applied to an antenna module for non-contact data communication. In such an antenna module, a sheet-like soft magnetic material is laminated on one surface of a base substrate as a support and a metal shield plate is laminated on the other surface with double-sided tape, and copper, aluminum, or the like is further laminated on the soft magnetic material. It has a structure in which an antenna coil such as a metal pattern cover is formed. The antenna coil is for non-contact IC tag functions, and is used to communicate with the antenna unit of an external reader / writer by inductive coupling. The antenna coil is connected to the signal processing circuit unit. Such a signal processing circuit unit is composed of a signal processing circuit necessary for contactless data communication and an electronic component such as an IC chip storing information and a tuning capacitor, and is disposed inside the antenna coil. It may be arranged outside. In addition, it is connected to the printed circuit board of the mobile communication terminal via an external connection part attached to the base substrate. Here, the base substrate may be a rigid substrate such as a glass epoxy substrate or an insulating flexible substrate mainly composed of a plastic film such as polyimide, polyethylene terephthalate, or polyethylene terephthalate. Also, the metal shield plate is used for coarse adjustment of the resonance frequency of the antenna module, and is provided so as not to cause a large change in the resonance frequency of the antenna module when it is incorporated in a mobile communication terminal! /ヽ. Examples of such metal shield plates include stainless steel plates, copper plates, and aluminum plates.

When data communication is performed with a reader / writer using a mobile communication terminal such as a mobile phone provided with such an antenna module, the anten module is brought close to the antenna unit of the reader / writer. Then, the electromagnetic wave or high-frequency magnetic field transmitted from the antenna force of the reader / writer passes through the antenna coil of the antenna module, so that an induced current corresponding to the strength of the electromagnetic wave or high-frequency magnetic field is generated in the antenna coil. This induced current is rectified in the signal processing circuit unit and converted into a read voltage for information recorded on the IC chip. The read information is modulated by the signal processing circuit unit, and is read via the antenna coil. It is transmitted to the antenna unit of one writer.

Example

Next, specific implementation of the soft magnetic sheet to which the present invention is applied will be described based on experimental results.

[0059] Examples 1A-4A

A soft magnetic paint was prepared by uniformly mixing the ingredients shown in Table 1 with a planetary mixer or dissolver. In these paints, as a binder, a hydroxyl group value of 6. OKOHmg / g, a number average molecular weight of 24000, a glass transition point of 4 ° C, a phosphorus content of 3.9% by weight, a phosphorus-containing polyester resin (Byron 537) , Manufactured by Toyobo Co., Ltd.). In addition, block isocyanate (trade name Coronate 2507, manufactured by Nippon Polyurethane Co., Ltd.) was used as a crosslinking agent. Soft magnetic powders include Fe Si-Cr-Ni powder (JEMCO), Fe Si-Al powder (Mate Co., Ltd.), SiO-coated Fe Si-Cr-Ni powder (JEMC)

2

On the powder manufactured by O company, a 5-nm: LOnm thick SiO film was formed using a vibration sputtering device.

2

Powder) or acrylic resin-coated Fe Si-Cr Ni powder After the surface of CiEMCO powder is treated with a silan coupling agent, 0.01 μm to 0.1 μm thick acrylic resin-coated powder is used. It was.

[0060] The obtained soft magnetic paint was applied to a peeled polyester terephthalate film (peeled PET film) (Teijin Co., Ltd.) that had been peeled on one side with a single coater so that the solid content of the paint would be 180 gZm ² And dried at 115 ° C. to obtain an uncured soft magnetic sheet supported by a peeled PET film.

[0061] Next, the peeled PET film was removed and five uncured soft magnetic sheets were laminated, and between the laminator rolls (the upper and lower roll temperatures were 150 ° C, the linear pressure was 13.4 kgfZcm, The line speed was set to 0.5 mZ.) 20 times, the bridge was cured while being oriented by compression to obtain a soft magnetic sheet.

[0062] Comparative Example 1A

A glass transition point Tg above room temperature (35 ° C) as a noinder and a low hydroxyl value! Polyester resin (trade name UE3500, hydroxyl value = 4) manufactured by Utica Co., Ltd. By the same operation, a crosslinked and hardened soft magnetic sheet was obtained. [0063] Comparative Example 2A

A cross-linked and hardened magnetic sheet was prepared in the same manner as in Example 1A, except that the block isocyanate block additive was not added.

[0064] [Table 1]

[0065] Regarding the obtained cross-linked and hardened soft magnetic sheets (Examples 1A to 4A and Comparative Examples 1A to 2A), V thickness, sheet thickness, magnetic properties (permeability μ ′, magnetic loss μ〃) , Performance factor Q), specific gravity, and communication distance. In addition, the thickness and magnetic properties (μ ′, μQ) of the soft magnetic sheet after being held for 96 hours in a high-temperature and high-humidity environment of 85 ° C. and 85% Rh were measured. The thickness change rate, specific gravity change rate, and 'change rate of the magnetic sheet were calculated. The communication distance was measured by placing the manufactured soft magnetic sheet between the antenna device and the shield plate and mounting it on a mobile phone. The effective permeability 'is a ring-shaped sample with a diameter of 7 mm, and the conductor coil is turned 5 turns, and the AC permeability at the carrier frequency (13. 56 MHz) is measured using an impedance analyzer. Obtained by quantitative determination. The results are shown in Table 2.

It should be noted that the magnetic characteristics were determined according to the following criteria using the magnetic permeability μ ′ as an index.

[0067] (When Fe-Si-Cr is used as soft magnetic powder)

®: 42≤ _i u

○: 38≤ / ζ '<42

X: n '<34

[0068] (When Fe-Si-Al is used as soft magnetic powder)

○: 60≤ / ζ '<65

Α: 55≤μ ^/ <60

X: μ '<55

[0069] (When using SiO-coated Fe-Si-Cr as soft magnetic powder)

2

○: 38≤ / ζ '<42

Α: 3Α≤μ '<38

X: μ '<34

[0070] (When using acrylic resin coated Fe-S and Cr as soft magnetic powder)

○: 38≤ / ζ '<42

Α: 3Α≤μ '<38

X: μ '<34

[0071] In addition, the rate of change in specific gravity, rate of change, and rate of change in sheet thickness were evaluated according to the following criteria:

[0072] (Specific gravity change rate)

◎: Less than 1%

○: 1 or more and less than 3%

Δ: 3% or more and less than 5%

X: 5% or more

[0073] {Change rate of μ ')

◎: Less than 1%

○: 1 or more and less than 3%

Δ: 3% or more and less than 5% X: 5% or more

[0074] (Sheet thickness change rate)

®: Less than 1%

○: 1% or more and less than 3%

Δ: 3% or more and less than 5%

X: 5% or more

[0075] [Table 2]

[0076] From Table 2, it can be seen that in Examples 1A to 4A, soft magnetic sheets with small dimensional change and magnetic property change were obtained even in a high temperature and high humidity environment. For example, when Comparative Example 2A is compared with each Example, the thickness change rate of the soft magnetic sheet is small in Examples. Also, when compared with Comparative Example 1, the soft magnetic sheet of each Example It can be seen that there is little or no decrease in magnetic properties after the test.

[0077] Example 1B

In accordance with the formulation (parts by weight) shown in Table 3, phosphorus-added polyester resin (Byron 537, manufactured by Toyobo Co., Ltd.), flat soft magnetic powder (Fe—Si—Cr—Ni, manufactured by JEMCO), and silane Power A soft magnetic coating is prepared by mixing a pulling agent (SH6040, Toray Dow Coung), isopropyl alcohol (IPA), and block isocyanate (Coronate 2507, Nippon Polyurethane Co., Ltd.). Apply to the peeled PET film (Teijin) with a roll coater so that the solid content of the paint is 180 gZm ^2, and dry for 10 minutes at 115 ° C. Uncured soft magnetic sheet supported by the peeled PET film Obtained.

[0078] Next, the peeled PET film was removed, and five uncured soft magnetic sheets were laminated, and between the laminator rolls (the temperature of the upper and lower rolls was 110 ° C, the linear pressure was 3.3 kgfZcm, The line speed was set to 0.5 mZ min.) 10 times to compress and orient the soft magnetic powder in the uncured soft magnetic sheet, and further compress at 150 ° C for 10 min at a pressure of 5 kgZcm ² This was cross-linked and cured to obtain a soft magnetic sheet. The obtained soft magnetic sheet had a small decrease in magnetic properties even when left in a high temperature, high temperature and high humidity environment with a large specific gravity.

[0079] Example 2B

Except for not performing compression using a laminator, the procedure of Example 1B was repeated to obtain a crosslinked and hardened soft magnetic sheet. The obtained soft magnetic sheet had a small decrease in magnetic properties even when left in a high temperature and high humidity environment with a large specific gravity.

[0080] Example 3B

By repeating the same operation as in Example 1B, except that the drying temperature of the soft magnetic coating material applied to the peeled PET film was 125 ° C., a crosslinked and hardened soft magnetic sheet was obtained. In the obtained soft magnetic sheet, when the soft magnetic paint is dried at 125 ° C, the block isocyanate block dissociates and partially crosslinks. Although it was slightly smaller than that of IB, it was a practically acceptable value.

[0081] Comparative Example 1B

A cross-linked and hardened soft magnetic sheet was obtained by repeating the same operation as in Example 1B, except that isocyanate (Coronate HL, manufactured by Nippon Polyurethane Co., Ltd.) was used instead of block isocyanate. The obtained soft magnetic sheet used unblocked isocyanate, so that the isocyanate and the phosphorus-containing polyester-based resin were cross-linked in the drying step, and the specific gravity could not be increased.

[0082] Comparative Example 2B An uncured soft magnetic sheet was obtained by repeating the operation of Example 1B, except that no block isocyanate was used and the drying temperature of the soft magnetic coating material was 120 ° C. Next, the peeled PET film was removed, and five uncured soft magnetic sheets were laminated, and then crosslinked and cured by compression at 150 ° C for 10 minutes at a pressure of 5 KgZcm ² without compression by a laminator. A soft magnetic sheet was obtained. Since the obtained soft magnetic sheet was not crosslinked, the specific gravity and magnetic properties after the environmental test were lowered.

[0083] For the obtained crosslinked and hardened soft magnetic sheets (Examples 1B to 3B and Comparative Examples 1B to 2B), the magnetic properties (permeability μ ′, magnetic loss μ〃, performance coefficient Q) and specific gravity were determined. It was measured. In addition, the magnetic properties of the soft magnetic sheet after being held in a high-temperature and high-humidity environment at 60 ° C and 95% Rh for 192 hours (μQ) were measured. The rate and the rate of change were calculated and evaluated as in Example 1A. The results are shown in Table 3.

Note that the magnetic characteristics were determined according to the following criteria using the permeability μ ′ as an index.

[0085] (Fe-Si-Cr-Ni is used as soft magnetic powder)

®: 42≤ _i u

○: 38≤ / ζ '<42

X: n '<34

Ss0083 [0087] Example 4B

In accordance with the formulation (parts by weight) shown in Table 4, phosphorus-added polyester resin (Byron 537, manufactured by Toyobo Co., Ltd.), flat soft magnetic powder (Fe-Si-Al, manufactured by Mate Co., Ltd.), and silane cutlet A soft magnetic paint is prepared by mixing with a pulling agent (SH6040, Toray Dow Coung), isopropyl alcohol (IPA) and block isocyanate (Coronate 2507, Nippon Polyurethane Co., Ltd.). The film was applied to a PET film (Teijin) with a roll coater so that the solid content of the paint was 180 gZ m ² and dried at 115 ° C. for 10 minutes to obtain an uncured soft magnetic sheet supported by the peeled PET film.

[0088] Next, the peeled PET film was removed and five uncured soft magnetic sheets were laminated, and between the laminator rolls (the temperature of the upper and lower rolls was 110 ° C, the linear pressure was 3.3 kgfZcm, The line speed was set to 0.5 mZ min.)) 10 times, and then oriented by compression, and further crosslinked and cured by compression at 150 ° C for 10 min at a pressure of 6 kgZcm ² to obtain a soft magnetic sheet. It was. The obtained soft magnetic sheet had a small decrease in magnetic properties even when left in a high temperature, high temperature and high humidity environment with a large specific gravity.

[0089] Example 5B

Except for not performing compression using a laminator, the procedure of Example 4B was repeated to obtain a crosslinked and hardened soft magnetic sheet. The obtained soft magnetic sheet had a small decrease in magnetic properties even when left in a high temperature and high humidity environment with a large specific gravity.

[0090] Example 6B

By repeating the same operation as in Example 4B, except that the drying temperature of the soft magnetic coating material applied to the peeled PET film was 125 ° C, a crosslinked and hardened soft magnetic sheet was obtained. In the obtained soft magnetic sheet, when the soft magnetic paint is dried at 125 ° C, the block isocyanate block dissociates and partially crosslinks. Although it was slightly smaller than the case of 4 mm, it was a value that had no practical problem.

[0091] Comparative Example 3

A crosslink-cured soft magnetic sheet was obtained by repeating the same operation as in Example 4B, except that isocyanate (Coronate HL, manufactured by Nippon Polyurethane Co., Ltd.) was used in place of the block isocyanate. The resulting soft magnetic sheet is an unblocked isocyanate. In the drying process, the isocyanate and the phosphorus-containing polyester-based resin were cross-linked in the drying step, and the specific gravity could not be increased.

[0092] Comparative Example 4B

An uncured soft magnetic sheet was obtained by repeating the operation of Example 4B, except that no block isocyanate was used and the drying temperature of the soft magnetic coating material was 120 ° C. Next, the peeled PET film was removed, 5 uncured soft magnetic sheets were stacked, and crosslinked and cured by compression at 150 ° C for 10 minutes at a pressure of 6 KgZcm ² without compression by a laminator. A soft magnetic sheet was obtained. Since the obtained soft magnetic sheet was not crosslinked, the specific gravity and magnetic properties after the environmental test were lowered.

[0093] For the obtained cross-linked hardened soft magnetic sheets (Examples 4B to 6B and Comparative Examples 3B to 4B), the magnetic properties (permeability μ ′, magnetic loss μ〃, performance coefficient Q) and specific gravity were It was measured. In addition, the magnetic properties of the soft magnetic sheet after being held in a high-temperature and high-humidity environment at 60 ° C and 95% Rh for 192 hours (μQ) were measured. The rate and the rate of change were calculated and evaluated as in Example 1A. The results are shown in Table 4.

It should be noted that the magnetic characteristics were determined based on the following criteria using the permeability μ ′ as an index.

[0095] (Fe-Si-Al is used as soft magnetic powder)

〇： 60≤ / ζ '<65

Α: 55≤ μ ^/ <60

X: μ '<55

i0096 [0097] Example 7B

As shown in Table 5, the operation of Example 1B was performed except that polyester resin having a hydroxyl value of 5. OKOHmg Zg (Byron 500, manufactured by Toyobo Co., Ltd.) was used instead of the polyester resin added with phosphorus. Was repeated to obtain a cross-linked and hardened soft magnetic sheet. The resulting soft magnetic sheet has a small decrease in magnetic properties even when left in a high temperature, high temperature and high humidity environment with a large specific gravity.

[0098] Example 8B

When the operation of Example 1B was repeated, the obtained soft magnetic sheet had a high specific gravity and a reproducible example in which the deterioration of the magnetic properties was small even when left in a high temperature and high humidity environment. Met.

[0099] Example 9B

The procedure of Example 1B is repeated except that the amount of the polyester resin added with phosphorus is changed from 100 parts by weight to 75 parts by weight, and 25 parts by weight of melamine cyanurate (MC610, manufactured by Nissan Chemical Industries, Ltd.) is newly added. Thus, a cross-linked and hardened soft magnetic sheet was obtained. The obtained soft magnetic sheet had a small decrease in magnetic properties even when left in a high temperature, high temperature and high humidity environment with a large specific gravity. In addition, when a combustion test was performed, the UL94 V-0 standard was satisfied.

[0100] Comparative Example 5B

Except for not using the block isocyanate, the procedure of Example 7B was repeated to obtain a crosslinked and hardened soft magnetic sheet. Since the obtained soft magnetic sheet was not cross-linked, the specific gravity and magnetic properties after the environmental test were lowered.

[0101] Comparative Example 6B

Other than using polyester resin added with phosphorus externally (polyester (Byron 500, Toyobo Co., Ltd.): Phosphate ester (CR741, Daihachi Chemical Co., Ltd.) = 100: 3) The same procedure as in Example 8B was repeated to obtain a crosslinked and hardened soft magnetic sheet. The obtained laminated soft magnetic sheet was peeled on the laminated surface, and the laminated soft magnetic sheet was peeled and separated into individual soft magnetic sheets after the environmental test.

[0102] Comparative Example 7B According to the formulation (parts by weight) shown in Table 5, phosphorus-added polyester resin (Byron 537, manufactured by Toyobo Co., Ltd.) and flat soft magnetic powder (Fe-Si-Cr-Ni, manufactured by JEMCO), A soft magnetic paint is prepared by mixing with block isocyanate (Coronate 2507, Nippon Polyurethane Co., Ltd.), and the soft magnetic paint is applied to a peeled PET film (Teijin) with a roll coater so that the solid content of the paint is 180 gZm ^2. It was applied and dried at 115 ° C for 10 minutes to obtain an uncured soft magnetic sheet supported by a release PET film.

[0103] Next, the peeled PET film was removed and five uncured soft magnetic sheets were laminated, and between the laminator rolls (the temperature of the upper and lower rolls was 110 ° C, the linear pressure was 3.3 kgfZcm, The line speed was set to 0.5 mZ min.)) 10 times, and then oriented by compression, and further crosslinked and cured by compression at 150 ° C for 10 min at a pressure of 6 kgZcm ² to obtain a soft magnetic sheet. It was. Since the obtained soft magnetic sheet did not use a silane coupling agent, the specific gravity did not increase even if it was compressed.

[0104] For the obtained cross-linked and hardened soft magnetic sheets (Examples 7B to 9B and Comparative Examples 5B to 7B), the magnetic properties (permeability μ ′, magnetic loss μ〃, performance coefficient Q) and specific gravity were determined. It was measured. In addition, the magnetic properties of the soft magnetic sheet after being held for 192 hours in a high-temperature drying environment or a high-temperature and high-humidity environment (high-temperature drying conditions 85 ° C, 10% Rh or less; high-temperature high-humidity conditions 60 ° C, 95% Rh) (μ ′,, Q) were measured, and the specific gravity change rate and the “change rate” of the soft magnetic sheet before and after the environmental test were calculated and evaluated in the same manner as in Example 1A. The results are shown in Table 5.

[0105] The magnetic characteristics were determined according to the following criteria using the permeability μ 'as an index.

[0106] (Fe-Si-Cr-Ni is used as soft magnetic powder)

®: 42≤ _i u

○: 38≤ / ζ '<42

X: n '<34

[Prop.] [¾] 75 [0108] Example 1 OB

As shown in Table 6, the procedure of Example 4B was repeated except that a polyester resin having a hydroxyl value of 5. OKOHmg / g (Byron 500, manufactured by Toyobo Co., Ltd.) was used instead of the polyester resin added with phosphorus. By repeating, a cross-linked and hardened soft magnetic sheet was obtained. The resulting soft magnetic sheet has a small decrease in magnetic properties even when left in a high temperature, high temperature and high humidity environment with a large specific gravity.

[0109] Example 11B

When the operation of Example 4B was repeated, the obtained soft magnetic sheet was a reproducible example in which the specific gravity was large and the magnetic properties were hardly deteriorated even when left in a high temperature and high humidity environment.

[0110] Example 12B

Furthermore, a cross-linked and hardened soft magnetic sheet was obtained by repeating the operation of Example 4B, except that 35 parts by weight of melamine cyanurate (MC610, manufactured by Nissan Chemical Industries, Ltd.) was blended. The obtained soft magnetic sheet had a small decrease in magnetic properties even when left in a high temperature, high temperature and high humidity environment with a large specific gravity. In addition, when a combustion test was performed, the UL94 V-0 standard was satisfied.

[0111] Comparative Example 8B

A soft magnetic sheet that was crosslinked and cured was obtained by repeating the procedure of Example 10B, except that the block isocyanate was not used. Since the obtained soft magnetic sheet was not cross-linked, the specific gravity and magnetic properties after the environmental test were lowered.

[0112] Comparative Example 9B

Other than using polyester resin added with phosphorus externally (polyester (Byron 500, Toyobo Co., Ltd.): Phosphate ester (CR741, Daihachi Chemical Co., Ltd.) = 100: 3) The same procedure as in Example 11B was repeated to obtain a crosslinked and hardened soft magnetic sheet. The obtained laminated soft magnetic sheet was peeled on the laminated surface, and the laminated soft magnetic sheet was peeled and separated into individual soft magnetic sheets after the environmental test.

[0113] Comparative Example 10B

According to the formulation (parts by weight) shown in Table 6, phosphorus-added polyester resin (Byron 537, East Yodobo Co., Ltd.), flat soft magnetic powder (Fe-Si-Al, manufactured by Mate Co., Ltd.) and block isocyanate (Coronate 2507, Nippon Polyurethane Co., Ltd.) to prepare a soft magnetic paint. Soft magnetic paint was applied to peeled PET film (Teijin) with a roll coater so that the solid content of the paint would be 180g / m ² , dried at 115 ° C for 10 minutes, and uncured supported by the peeled PET film A soft magnetic sheet was obtained.

[0114] Next, five uncured soft magnetic sheets from which the peeled PET film was removed were laminated, and between the laminator rolls (the temperature of the upper and lower rolls was 110 ° C, the linear pressure was 3.3 kgfZcm, the line speed Was set to 0.5 mZ min.) By passing 10 times through compression, and further crosslinked and cured by compression at 150 ° C. under a pressure of 6 kgZcm ² for 10 minutes to obtain a soft magnetic sheet. Since the obtained soft magnetic sheet did not use a silane coupling agent, the specific gravity did not increase even if it was compressed.

[0115] Regarding the obtained cross-linked and hardened soft magnetic sheets (Examples 10B to 12B and Comparative Examples 8B to 10B), the magnetic properties (permeability μ ', magnetic loss μ ", performance coefficient Q) and specific gravity were determined. The soft magnetic sheet after being held for 192 hours in a high-temperature dry environment or a high-temperature and high-humidity environment (high-temperature conditions 85 ° C, 10% Rh or less; high-temperature high-humidity conditions 60 ° C, 95% Rh) The magnetic properties (μ ′,, Q) of the film were measured, and the specific gravity change rate and the change rate of the soft magnetic sheet before and after the environmental test were calculated and evaluated in the same manner as in Example 1A. Shown in.

[0116] The magnetic characteristics were determined according to the following criteria using the magnetic permeability; ζ 'as an index.

[0117] (Fe-Si-Al is used as soft magnetic powder)

○: 60≤ / ζ '<65

X: μ '<55 [] ¾¾J¾ Chamber 0119 i13K 17B 11Β12ω

[] I0118 According to the formulation (parts by weight) shown in Table 7, phosphorus-added polyester resin (Byron 537, manufactured by Toyobo Co., Ltd.) and flat soft magnetic powder (Fe-Si-Cr-Ni, manufactured by JEMCO), Silane force A coupling agent, IPA, and block isocyanate (Coronate 2507, Nippon Polyurethane) are mixed to prepare a soft magnetic paint, and the soft magnetic paint is applied to a release PET film (Teijin). The uncoated soft magnetic sheet supported by the peeled PET film was obtained by applying with a roll coater so that the amount was 180 gZm ² and drying at 115 ° C. for 10 minutes.

[0120] Table 7 shows the percent particle diameter, specific surface area, saturation magnetization, coercive force, tap density, and flatness of the soft magnetic powder used.

[0121] For the obtained cross-linked and hardened soft magnetic sheets (Examples 13B to 17B and Comparative Examples 11B to 12B), the magnetic properties (permeability μ ', magnetic loss μ ", performance coefficient Q) and specific gravity were determined. The soft magnetic sheet after being held for 192 hours in a high-temperature dry environment or high-temperature and high-humidity environment (high-temperature dry condition 85 ° C, 10% Rh or less; high-temperature high-humidity condition 60 ° C, 95% Rh) Was measured, and the specific gravity change rate and permeability change rate of the soft magnetic sheet before and after the environmental test were calculated and evaluated in the same manner as in Example 1A. Shown in

[0122] The magnetic characteristics were determined based on the following criteria using the permeability μ 'as an index.

[0123] (Fe-Si-Cr-Ni is used as soft magnetic powder)

®: 42≤ _i u

○: 38≤ / ζ '<42

X: n '<34

] ¾ Chamber ¾012 薪 δ5: ί? ¾¾4 H 13Β17θ ヾ ¾o. ~ 〜O

Ingredients (parts by weight) Examples 13B to 17B, Comparative Examples 11B to 12B

0124 Since it is in the range of 45 gZml and the force is in the range of 0.4 to 1.20 m ² Zg, the magnetic permeability μ 'and Q showed large values.

[0126] On the other hand, the soft magnetic sheet of Comparative Example 11B has a tap density of more than 1.45 g / ml and a specific surface area of less than 0.4 m ² Zg. The value was small. The soft magnetic sheet of Comparative Example 12B had a tap density of less than 0.55 gZml and a specific surface area of more than 1.20 m ² Zg. Therefore, although the value of permeability 'was large, the value of Q was small.

[0127] Example 18B, Comparative Example 13B

The soft magnetic sheets of Example 15B (with crosslinking) and Comparative Example 2B (without crosslinking) were placed between the antenna device and the shield plate and mounted on a mobile phone before and after environmental testing (60 ° C, 95% Rh, 192h). r) The communication distance before and after was measured. The results obtained are shown in Table 8.

[0128] [Table 8]

[0129] As can be seen from Table 8, the communication distance of the soft magnetic sheet of Example 18B obtained by crosslinking Noinda resin did not change substantially before and after the environmental test, but the binder resin was bridged. The communication distance of the soft magnetic sheet of Comparative Example 13B that was not changed greatly before and after the environmental test.

Industrial applicability

[0130] The soft magnetic material of the present invention is obtained by cross-linking the soft magnetic powder in the binder resin in a densely oriented state to increase the specific gravity. Therefore, the dimensional change under high temperature or high temperature and high humidity environment. In addition, since the change in magnetic properties is small, it is useful for electronic devices such as antenna modules and portable communication terminals.

Claims

The scope of the claims

[I] A soft magnetic material in which at least a flat soft magnetic powder is dispersed in a cross-linked polyester resin.

[2] The soft magnetic material according to [1], wherein the flat soft magnetic powder is oriented in substantially the same in-plane direction.

[3] 400 to 600% by weight of the flat soft magnetic powder, and 60 to 1 of the cross-linked polyester resin

The soft magnetic material according to claim 1 or 2 containing 50% by weight.

[4] The soft magnetic material according to any one of claims 1 to 3, wherein the shape is a sheet.

[5] The polyester-based resin has a glass transition temperature of −20 ° C. to 40 ° C. and a hydroxyl value of 4.5 mgK.

The soft magnetic material according to any one of claims 1 to 4, which is OHZg to 15 mg KOHZg.

[6] The polyester-based resin is crosslinked with a block isocyanate.

The soft magnetic material according to any one of 5 to 5.

7. The soft magnetic material according to any one of claims 1 to 6, wherein the polyester-based resin has flame retardancy.

8. The soft magnetic material according to claim 7, wherein the polyester-based resin is a phosphorus-containing polyester-based resin.

9. The soft magnetic material according to claim 8, wherein the phosphorus-added polyester-based resin has a phosphate residue in the molecule.

[10] The soft magnetic material according to any one of [1] to [9], wherein the flat soft magnetic powder is subjected to a silane coupling treatment.

[II] The soft magnetic material according to any one of claims 1 to 10, wherein the flat soft magnetic powder is coated with an insulating layer.

12. The soft magnetic material according to claim 11, wherein the insulating layer is a metal oxide film or a resin film.

[13] The soft magnetic material according to any one of [1] to [12], wherein the flat soft magnetic powder is an Fe—Si—A1 alloy powder or an Fe—Si—Cr—Ni alloy powder.

[14] 6—31—0: — ^ Alloy powder cut density 0.55-1.45 gZml, specific surface area 0.4

14. The soft magnetic material according to claim 13, which exhibits 5 to 1.20 mg and a flatness of 8 to 24.

[15] The real part force of the complex relative permeability is 35 or more. Soft magnetic material.

16. The soft magnetic material according to any one of claims 1 to 15, having a specific gravity of 3.0 or more.

[17] The dimensional change after being left in an environment of 60 ° C to 95 ° C is 3% or less.

V, soft magnetic material according to any of the above.

[18] The dimensional change after being left in a high-temperature and high-humidity environment at a temperature of 40 ° C to 90 ° C and a relative humidity of 60 to 95% is 3% or less. Soft magnetic material.

[19] An electronic device comprising the soft magnetic material according to any one of claims 1 to 18.

20. An antenna module, wherein the antenna module is laminated on a support body on which a soft magnetic material force antenna coil according to any one of claims 1 to 18 is formed.

21. The antenna module according to claim 20, wherein the antenna coil is electrically connected to a signal processing circuit section.

[22] The antenna module according to [20] or [21], wherein the metal shield plate is laminated on a support opposite to the side on which the soft magnetic material is laminated.

[23] A mobile communication terminal comprising the antenna module according to any one of claims 20 to 22.

[24] A soft magnetic composition obtained by mixing at least a flat soft magnetic powder, a polyester-based resin, a crosslinking agent, and a solvent is applied onto a release substrate, and dried at a temperature at which a crosslinking reaction does not substantially occur. A method for producing a soft magnetic material, which is compressed at a temperature at which a crosslinking reaction occurs.

[25] The process according to claim 24, wherein after the drying at a temperature at which the crosslinking reaction does not substantially occur, the compression is performed at a temperature at which the crosslinking reaction does not substantially occur before the compression at the temperature at which the crosslinking reaction occurs.

[26] After applying a soft magnetic composition comprising at least a flat soft magnetic powder, a polyester-based resin, a crosslinking agent, and a solvent on a release substrate, drying is performed at a temperature at which a crosslinking reaction does not substantially occur. By repeating the removal of the release substrate, at least two dry sheets of the soft magnetic composition are obtained, the at least two dry sheets are laminated, and compressed at a temperature at which a crosslinking reaction occurs. A method for producing a soft magnetic sheet.

27. The production method according to claim 26, wherein after the lamination of at least two dry sheets, the compression is performed at a temperature at which the crosslinking reaction does not substantially occur before the compression at the temperature at which the crosslinking reaction occurs.