KR102617523B1 - magnetic paste - Google Patents

Abstract

A magnetic paste containing (A) magnetic powder, (B) organized layered silicate mineral, and (C) binder resin.

Description

magnetic paste

The present invention relates to a magnetic paste, an inductor element, and a circuit board obtained using the magnetic paste.

Inductor elements are widely installed in information terminals such as mobile phones and smartphones. Conventionally, independent inductor components were mounted on a board, but recently, a method of forming a coil using a conductor pattern of the board and installing the inductor element inside the board has been used.

As a method of installing an inductor element inside a substrate, for example, a method of forming a magnetic layer by screen printing a paste material containing a magnetic material on a substrate containing wiring is known (see Patent Document 1 and Patent Document 2) ).

Patent Document 1: Japanese Patent Application Laid-Open No. 6-69058 Patent Document 2: Japanese Patent Application Laid-Open No. 2017-63100

Conventional paste materials have a high resin exudation property. Therefore, when screen printing is performed using a paste material and cured to form a magnetic layer, some of the resin component and magnetic powder constituting the paste material are extruded from the edge portion of the magnetic layer. Since it is difficult to form a conductor layer and install components in the area on the substrate where the extracted components are located, the degree of freedom in circuit design is reduced or it is an obstacle to miniaturization of the circuit. Patent Document 1 and Patent Document 2 describe a method of suppressing resin bleeding by improving the screen printing method or improving the structure of the inductor element, but the methods described in Patent Document 1 and Patent Document 2 are necessarily satisfactory. It wasn't something nice.

The present invention was made in consideration of the above circumstances, and its purpose is to provide a magnetic paste capable of obtaining a cured product with suppressed resin exudation, and an inductor element and a circuit board using the magnetic paste.

As a result of intensive research to achieve the above object, the present inventor discovered that resin exudation was suppressed by using a magnetic paste containing an organic layered silicate mineral, and completed the present invention.

That is, the present invention includes the following contents.

[1] (A) magnetic powder,

(B) organized layered silicate minerals, and

(C) Magnetic paste containing binder resin.

[2] The magnetic paste according to [1], wherein the component (B) contains organic smectite.

[3] The magnetic paste according to [2], wherein the component (B) contains smectite ion-exchanged with quaternary ammonium ions.

[4] The magnetic paste according to any one of [1] to [3], wherein the component (B) is at least one selected from organic hectorite and organic montmorillonite.

[5] The magnetic paste according to [4], wherein the component (B) is at least one selected from hectorite ion-exchanged with quaternary ammonium ions and montmorillonite ion-exchanged with quaternary ammonium ions.

[6] The magnetic paste according to any one of [1] to [5], wherein the component (C) contains a thermosetting resin.

[7] The magnetic paste according to any one of [1] to [6], wherein the component (C) contains an epoxy resin.

[8] The magnetic paste according to any one of [1] to [7], wherein the (A) component is at least one selected from iron oxide powder and iron alloy-based metal powder.

[9] The content of component (B) when the non-volatile component in the magnetic paste is 100% by mass is B1, and the content of component (C) when the nonvolatile component in the magnetic paste is 100% by mass is C1. The magnetic paste according to any one of [1] to [8], wherein C1/B1 is 1 or more and 30 or less.

[10] The magnetic paste according to any one of [1] to [9], for forming an inductor element.

[11] An inductor element comprising a magnetic layer that is a cured product of the magnetic paste according to any one of [1] to [10].

[12] A circuit board including the inductor element described in [11].

According to the present invention, a magnetic paste capable of obtaining a cured product with suppressed resin exudation, and an inductor element and a circuit board using the magnetic paste can be provided.

[Figure 1] Figure 1 is a schematic plan view of an inductor element according to an embodiment of the present invention.
[FIG. 2] FIG. 2 is a cross-sectional view schematically showing an example of a cross-section of a magnetic layer formed on a substrate.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. Additionally, each drawing merely schematically shows the shape, size, and arrangement of components to enable the invention to be understood. The present invention is not limited to the embodiments below, and each component can be changed appropriately. In addition, the configuration according to the embodiment of the present invention is not necessarily limited to being manufactured or used according to the arrangement of the illustrated example.

[Magnetic paste]

The magnetic paste of the present invention includes (A) magnetic powder, (B) organized layered silicate mineral, and (C) binder resin.

In the present invention, a cured product with suppressed resin exudation can be obtained by containing (B) the organic layered silicate mineral. In addition, the obtained cured product is generally capable of improving relative magnetic permeability and reducing magnetic loss in a frequency range of 10 to 200 MHz.

The magnetic paste may further include (D) a curing accelerator, (E) a dispersant, and (F) other additives, if necessary. Hereinafter, each component included in the magnetic paste of the present invention will be described in detail.

<(A) Magnetic powder>

The magnetic paste contains (A) magnetic powder. (A) Examples of magnetic powder include pure iron powder; Mg-Zn-based ferrite, Fe-Mn-based ferrite, Mn-Zn-based ferrite, Mn-Mg-based ferrite, Cu-Zn-based ferrite, Mg-Mn-Sr-based ferrite, Ni-Zn-based ferrite, Ba-Zn-based ferrite, iron oxides such as Ba-Mg-based ferrite, Ba-Ni-based ferrite, Ba-Co-based ferrite, Ba-Ni-Co-based ferrite, Y-based ferrite, iron(III) oxide, and triiron tetroxide; Fe-Si-based alloy powder, Fe-Si-Al-based alloy powder, Fe-Cr-based alloy powder, Fe-Cr-Si-based alloy powder, Fe-Ni-Cr-based alloy powder, Fe-Cr-Al-based alloy powder, Iron alloy-based metal powders such as Fe-Ni-based alloy powder, Fe-Ni-Mo-based alloy powder, Fe-Ni-Mo-Cu-based alloy powder, Fe-Co-based alloy powder, or Fe-Ni-Co-based alloy powder; Amorphous alloys such as Co-based amorphous can be mentioned.

Among these, the magnetic powder (A) is preferably at least one selected from iron oxide powder and iron alloy-based metal powder. The iron oxide powder is preferably ferrite containing at least one selected from Ni, Cu, Mn, and Zn. Furthermore, the iron alloy-based metal powder is preferably an iron alloy-based metal powder containing at least one type selected from Si, Cr, Al, Ni, and Co.

(A) As the magnetic powder, commercially available magnetic powder can be used. Specific examples of commercially available magnetic powder that can be used include “M05S” manufactured by Powder Tech; “PST-S” manufactured by Sanyo Tokushu Seiko Co., Ltd.; “AW2-08”, “AW2-08PF20F”, “AW2-08PF10F”, “AW2-08PF3F”, “Fe-3.5Si-4.5CrPF20F”, “Fe-50NiPF20F”, “Fe-80Ni-4MoPF20F” manufactured by Epson Atmix. 」; “LD-M”, “LD-MH”, “KNI-106”, “KNI-106GSM”, “KNI-106GS”, “KNI-109”, “KNI-109GSM”, “KNI-109GS” manufactured by JFE Chemical Co., Ltd. 」; “KNS-415”, “BSF-547”, “BSF-029”, “BSN-125”, “BSN-125”, “BSN-714”, “BSN-828”, “S-1281” manufactured by Toda Kogyoso Co., Ltd. ”, 「S-1641」, 「S-1651」, 「S-1470」, 「S-1511」, 「S-2430」; “JR09P2” manufactured by Nippon Chukagaku Kogyo; “Nanotek” manufactured by CIK Nanotech; “JEMK-S” and “JEMK-H” manufactured by Kinsei Matex, and “Yttrium iron oxide” manufactured by ALDRICH. Magnetic powder may be used individually, or two or more types may be used in combination.

(A) The magnetic powder is preferably spherical. The length of the major axis of the magnetic powder divided by the length of the minor axis (aspect ratio) is preferably 2 or less, more preferably 1.5 or less, and even more preferably 1.2 or less. In general, it is easier to improve the relative magnetic permeability when the magnetic powder has a flat shape rather than a spherical shape. However, it is generally preferable to use spherical magnetic powder from the viewpoint of lowering magnetic loss and obtaining a paste with a desirable viscosity.

(A) The average particle diameter of the magnetic powder is preferably 0.01 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more from the viewpoint of improving relative magnetic permeability. Additionally, it is preferably 10 μm or less, more preferably 9 μm or less, and even more preferably 8 μm or less.

(A) The average particle diameter of magnetic powder can be measured by a laser diffraction/scattering method based on Mie scattering theory. Specifically, the particle diameter distribution of the magnetic powder can be prepared on a volume basis using a laser diffraction scattering type particle diameter distribution measuring device, and the median diameter can be measured as the average particle diameter. The measurement sample can preferably be one in which magnetic powder is dispersed in water by ultrasonic waves. As a laser diffraction scattering type particle diameter distribution measuring device, "LA-500" manufactured by Horiba Chemical Industries, Ltd., "SALD-2200" manufactured by Shimadzu Chemical Industries, etc. can be used.

(A) The specific surface area of the magnetic powder is preferably 0.05 m2/g or more, more preferably 0.1 m2/g or more, and even more preferably 0.3 m2/g or more from the viewpoint of improving the relative magnetic permeability. Additionally, it is preferably 10 m2/g or less, more preferably 8 m2/g or less, and even more preferably 5 m2/g or less. (A) The specific surface area of magnetic powder can be measured by the BET method.

(A) The content (volume %) of the magnetic powder is preferably 10 volume % or more, when the non-volatile component in the magnetic paste is 100 volume %, from the viewpoint of improving the relative magnetic permeability and reducing magnetic loss. Preferably it is 20 volume% or more, more preferably 30 volume% or more. Moreover, it is preferably 85 volume% or less, more preferably 80 volume% or less, and even more preferably 75 volume% or less.

(A) The content (% by mass) of the magnetic powder is preferably 60% by mass or more, when the non-volatile component in the magnetic paste is 100% by mass, from the viewpoint of improving the relative magnetic permeability and reducing magnetic loss. Preferably it is 65 mass% or more, more preferably 70 mass% or more. Moreover, it is preferably 98 mass% or less, more preferably 96 mass% or less, and even more preferably 94 mass% or less.

In addition, in the present invention, unless otherwise specified, the content of each component in the magnetic paste is a value assuming that the non-volatile component in the magnetic paste is 100% by mass.

<(B) Organized layered silicate mineral>

The magnetic paste contains (B) organized layered silicate mineral. (B) By including the organic layered silicate mineral in the magnetic paste, it becomes possible to obtain a cured product with suppressed resin exudation. Here, “organized” means “ion-exchanged with organic onium ions.”

Layered silicate minerals are also commonly called phyllosilicate minerals. Layered silicate minerals can be used individually or in combination of two or more types. Additionally, as the layered silicate mineral, natural products or compounds may be used. As the crystal structure of the layered silicate mineral, it is preferable to use a highly pure mineral that is regularly stacked in the c-axis direction, but a so-called mixed layered mineral in which the crystal cycle is disturbed and multiple types of crystal structures are mixed may be used.

Examples of layered silicate minerals include smectite, kaolinite, helloysite, talc, and mica. Among these, smectite is preferable from the viewpoint of obtaining a cured product that can effectively suppress resin exudation.

_{Smectite has the general formula :} There are more than one species, Y is at least one selected from the group consisting of Mg, Fe, Mn, Ni, Zn, Li, Al, and Cr, and Z is at least one selected from the group consisting of Si and Al. In addition, H ₂ O represents a water molecule bonded to an interlayer ion. n represents an integer and may vary significantly depending on the interlayer ion and relative humidity. It is expressed as natural or synthetic. Examples of smectite include hectorite, montmorillonite, beidellite, nontronite, saponite, iron saponite, soconite, stevensite, bentonite, or substituted products or derivatives thereof, or mixtures thereof. . Among these, hectorite and montmorillonite are preferable from the viewpoint of obtaining a cured product that can effectively suppress resin exudation.

Organic onium ion refers to an ion having an onium ion structure containing an organic group. This organic onium ion is usually contained in the interlayer portion of the silicate layer of the layered silicate mineral in component (B).

Examples of organic onium ions include organic ammonium ions, organic phosphonium ions, organic sulfonium ions, and organic imidazolium ions. Among them, from the viewpoint of obtaining a cured product with effectively suppressed resin exudation, organic ammonium ions and organic phosphonium ions are preferable, and organic ammonium ions are particularly preferable.

Examples of organic groups contained in organic onium ions include monovalent hydrocarbon groups such as alkyl groups, alkenyl groups, aryl groups, and aralkyl groups; hydroxyalkyl group; carboxyalkyl group; polyalkylene ether group; etc. can be mentioned. These organic groups may be used singly or in combination of two or more types. Among them, a monovalent hydrocarbon group and a polyalkylene ether group are preferable from the viewpoint of obtaining a cured product in which resin exudation is effectively suppressed.

As the monovalent hydrocarbon group, a monovalent aliphatic hydrocarbon group is preferable, a monovalent saturated aliphatic hydrocarbon group is more preferable, and an alkyl group is particularly preferable. The alkyl group may be linear or branched. Additionally, the number of carbon atoms of the monovalent hydrocarbon group is usually 1 to 40, preferably 1 to 25, and more preferably 1 to 20. When the monovalent hydrocarbon group satisfies the above desirable requirements, a cured product with particularly low resin exudation can be obtained.

Preferred examples of monovalent hydrocarbon groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, isobutyl, n-pentyl, isopentyl and neo. Pentyl group, t-pentyl group, n-hexyl group, isohexyl group, 1-methylpentyl group, 2-methylpentyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n -Undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group , n-icosyl group, etc.

The polyalkylene ether group represents a group represented by the following formula (I).

-(RO) _m -H(I)

In formula (I), R each independently represents an alkylene group. The number of carbon atoms in the alkylene group is preferably 2 to 20. Examples of the alkylene group include ethylene group and propylene group.

In formula (I), m represents an integer of 1 to 20.

Particularly preferable organic onium ions include organic onium ions represented by the following formula (II).

(II)

(II)

In formula (II), X ¹ represents a non-metal atom belonging to group 15 of the long periodic table. Therefore, X ¹ represents a nitrogen atom or a phosphorus atom. Among them, from the viewpoint of obtaining a cured product with effectively suppressed resin bleeding, X ¹ is preferably a nitrogen atom.

In formula (II), R ¹ represents the above organic group. Among organic groups, from the viewpoint of obtaining a cured product with effectively suppressed resin bleeding, those selected from the group consisting of monovalent hydrocarbon groups and polyalkylene ether groups are preferable, alkyl groups or polyalkylene ether groups are more preferable, and alkyl groups are more preferable. Particularly desirable.

In formula (II), R ² , R ³ and R ⁴ each independently represent a hydrogen atom and a group selected from the group consisting of the above organic groups. Among organic groups, from the viewpoint of obtaining a cured product with effectively suppressed resin bleeding, those selected from the group consisting of monovalent hydrocarbon groups and polyalkylene ether groups are preferable, alkyl groups or polyalkylene ether groups are more preferable, and alkyl groups are more preferable. Particularly desirable.

From the viewpoint of obtaining a cured product with effectively suppressed resin exudation, among organic onium ions, organic ammonium ions are preferable, secondary to quaternary organic ammonium ions are more preferable, and tertiary to quaternary organic ammonium ions are more preferable. More preferred, quaternary organic ammonium ions are particularly preferred. Therefore, in the organic onium ion represented by formula (II), it is preferable that at least one of R ² , R ³ and R ⁴ is an organic group, more preferably at least two are organic groups, and especially all three are organic groups. desirable.

Among the quaternary ammonium ions represented by formula (II), it is preferable that at least some of R ¹ , R ² , R ³ and R ⁴ are long-chain organic groups. Moreover, it is more preferable that some of R ¹ , R ² , R ³ and R ⁴ are long-chain organic groups and the remainder are short-chain organic groups. Among them, it is particularly preferable that among R ¹ , R ² , R ³ and R ⁴ , 2 to 3 are long-chain organic groups, and the remaining 1 to 2 are short-chain organic groups. A long-chain organic group usually refers to an organic group having 8 or more carbon atoms, preferably 12 or more carbon atoms. In addition, a short-chain organic group refers to an organic group having 1 to 7 carbon atoms. By using a quaternary ammonium ion that satisfies these requirements, a cured product with particularly low resin exudation property can be obtained, and the effect is particularly notable when the organic group is an alkyl group.

Preferred specific examples of organic onium ions include trimethyloctylammonium ion, trimethyldecylammonium ion, trimethyldodecylammonium ion, trimethyltetradecylammonium ion, trimethylhexadecylammonium ion, trimethyloctadecylammonium ion, trimethylicosylammonium ion, etc. trimethylalkylammonium ion; triethylalkylammonium ions such as triethyldodecyl ammonium ion, triethyltetradecylammonium ion, triethylhexadecyl ammonium ion, and triethyl octadecylammonium ion; tributylalkylammonium ions such as tributyldodecyl ammonium ion, tributyltetradecylammonium ion, tributylhexadecyl ammonium ion, and tributyl octadecylammonium ion; dimethyl dioctylammonium ion, dimethyl didecyl ammonium ion, dimethyldetetradecylammonium ion, dimethyldihexadecyl ammonium ion, dimethyldioctadecylammonium ion (dimethyldistearylammonium ion), dimethyldidodecyl ammonium ion, etc. dialkylammonium ion; Diethyldialkylammonium ions such as diethyldidodecyl ammonium ion, diethylditetradecylammonium ion, diethyldihexadecyl ammonium ion, and diethyldioctadecyl ammonium ion; Dibutyldioctylammonium ion, dibutyldidecylammonium ion, dibutyldidodecylammonium ion, dibutylditetradecylammonium ion, dibutyldihexadecylammonium ion, dibutyldioctadecylammonium ion, etc. alkylammonium ion; trialkylmethylammonium ions such as trioctylmethylammonium ion, tridodecylmethylammonium ion, and tritetradecylmethylammonium ion; trialkylethylammonium ions such as trioctylethylammonium ion and tridodecylethylammonium ion; trialkylbutylammonium ions such as trioctylbutylammonium ion and tridecylbutylammonium ion; and organic ammonium ions such as these.

Component (B) can be produced by ion-exchanging a layered silicate mineral with an organic onium ion. During ion exchange, the organic onium ion may be a salt (organic onium salt) of the organic onium ion and an anion. Examples of the anions include Cl ^- , Br ^- , NO ₃ ^- , OH ^- , CH ₃ COO ^- , CH ₃ SO ₃ ^-, and the like. In addition, these anions may be used individually or in combination of two or more types.

A specific example of the method for producing component (B) includes a method of mixing an aqueous dispersion of layered silicate mineral and an aqueous organic onium salt solution at an appropriate temperature (for example, 60°C to 70°C). Additionally, another specific example includes a method of appropriately mixing a layered silicate mineral and an organic onium salt.

(B) Components can be commercially available. Commercially available products include, for example, "Smectone STN" and "Smectone SAN" (organized hectorite) manufactured by Kunimine Kogyo Co., Ltd., "Orben M" (organized montmorillonite) manufactured by Shiraishi Kogyo Co., Ltd., and "S" manufactured by Hojun Co., Ltd. Ben N

(B) Organized layered silicate minerals may be used individually, or two or more types may be used in combination.

(B) The average particle diameter of the organic layered silicate mineral is preferably 1 nm to 100 μm, more preferably 5 nm to 50 μm, and still more preferably 10 nm to 10 μm. This average particle diameter can be measured in the same manner as for component (A).

(B) The content of the organic layered silicate mineral is preferably 0.1% by mass or more, more preferably 0.1% by mass or more, when the nonvolatile component in the magnetic paste is 100% by mass, from the viewpoint of obtaining a cured product with suppressed resin exudation. is 0.3 mass% or more, more preferably 0.5 mass% or more. The upper limit is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass, from the viewpoint of maintaining the magnetic properties well and improving printability by lowering the paste viscosity. It is less than mass%.

<(C) Binder Resin>

The magnetic paste contains (C) binder resin. (C) Binder resins include, for example, epoxy resins, phenol-based resins, naphthol-based resins, benzoxazine-based resins, activated ester-based resins, cyanate ester-based resins, carbodiimide-based resins, amine-based resins, and acid anhydrides. Thermosetting resins such as polymer resins; Thermoplastic resins such as phenoxy resin, acrylic resin, polyvinyl acetal resin, butyral resin, polyimide resin, polyamidoimide resin, polyethersulfone resin, and polysulfone resin can be mentioned. (C) As the binder resin, it is preferable to use a thermosetting resin used to form the insulating layer of a wiring board, and epoxy resin is especially preferable. (C) Binder resin may be used individually or in combination of two or more types. Below, each resin is explained. Here, phenol-based resins, naphthol-based resins, benzoxazine-based resins, activated ester-based resins, cyanate ester-based resins, carbodiimide-based resins, amine-based resins, and acid anhydride-based resins react with epoxy resins to produce magnetic properties. Components that can harden the paste are sometimes collectively referred to as “curing agents.”

- Thermosetting resin -

Epoxy resins as thermosetting resins include, for example, glycirol-type epoxy resins; Bisphenol A type epoxy resin; Bisphenol F type epoxy resin; Bisphenol S type epoxy resin; Bisphenol AF type epoxy resin; Dicyclopentadiene type epoxy resin; Trisphenol type epoxy resin; Phenol novolac type epoxy resin; tert-butyl-catechol type epoxy resin; Epoxy resins having a condensed ring structure such as naphthol novolak-type epoxy resin, naphthalene-type epoxy resin, naphthol-type epoxy resin, and anthracene-type epoxy resin; Glycidylamine type epoxy resin; Glycidyl ester type epoxy resin; Cresol novolak-type epoxy resin; Biphenyl type epoxy resin; Linear aliphatic epoxy resin; Epoxy resin having a butadiene structure; Alicyclic epoxy resin; Heterocyclic epoxy resin; Spirocyclic-containing epoxy resin; Cyclohexanedimethanol type epoxy resin; Trimethylol type epoxy resin; Tetraphenylethane type epoxy resin, etc. can be mentioned. Epoxy resins may be used individually, or two or more types may be used in combination. The epoxy resin is preferably at least one selected from bisphenol A type epoxy resin and bisphenol F type epoxy resin.

It is preferable that the epoxy resin contains an epoxy resin having two or more epoxy groups in one molecule. Moreover, it is preferable that the epoxy resin has an aromatic structure, and when two or more types of epoxy resins are used, it is more preferable that at least one type has an aromatic structure. An aromatic structure is a chemical structure generally defined as aromatic, and also includes polycyclic aromatics and aromatic heterocycles. The ratio of the epoxy resin having two or more epoxy groups per molecule relative to 100% by mass of the non-volatile component of the epoxy resin is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass. It is more than %.

Epoxy resins include epoxy resins that are liquid at a temperature of 25°C (hereinafter sometimes referred to as “liquid epoxy resins”) and epoxy resins that are solid at a temperature of 25°C (hereinafter sometimes referred to as “solid epoxy resins”). There is. (C) When containing an epoxy resin as a component, the epoxy resin may contain only a liquid epoxy resin, may contain only a solid epoxy resin, or may contain a combination of a liquid epoxy resin and a solid epoxy resin. , from the viewpoint of reducing the viscosity of the magnetic paste, it is preferable to include only liquid epoxy resin.

Liquid epoxy resins include glycirol type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, Phenol novolak-type epoxy resins, alicyclic epoxy resins with an ester skeleton, cyclohexanedimethanol-type epoxy resins, and epoxy resins with a butadiene structure are preferred, and glycirol-type epoxy resins, bisphenol A-type epoxy resins, and bisphenol F Type epoxy resin is more preferable. Specific examples of the liquid epoxy resin include "HP4032", "HP4032D", and "HP4032SS" (naphthalene type epoxy resin) manufactured by DIC Corporation; “828US”, “jER828EL” (bisphenol A-type epoxy resin), “jER807” (bisphenol F-type epoxy resin), and “jER152” (phenol novolak-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; “630” and “630LSD” manufactured by Mitsubishi Chemical Corporation, “ED-523T” (glycyroll type epoxy resin (ADEKA glycirol)) manufactured by ADEKA Corporation, and “EP-3980S” (glycidylamine type epoxy resin) ), “EP-4088S” (dicyclopentadiene type epoxy resin); “ZX1059” manufactured by Shin-Nittetsu Sumikin Chemical Co., Ltd. (mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin); “EX-721” (glycidyl ester type epoxy resin) manufactured by Nagase Chemtex Corporation; “Celoxide 2021P” (alicyclic epoxy resin having an ester skeleton), “PB-3600” (epoxy resin having a butadiene structure) manufactured by Daicel Corporation; “ZX1658” and “ZX1658GS” (liquid 1,4-glycidylcyclohexane) manufactured by Nippon Chemical Co., Ltd. are included. These may be used individually or in combination of two or more types.

As solid epoxy resins, naphthalene type tetrafunctional epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, and naphthylene ether type epoxy resin. , anthracene-type epoxy resin, bisphenol-A-type epoxy resin, and tetraphenylethane-type epoxy resin are preferable, and naphthalene-type tetrafunctional epoxy resin, naphthol-type epoxy resin, and biphenyl-type epoxy resin are more preferable. Specific examples of solid epoxy resins include "HP4032H" (naphthalene-type epoxy resin), "HP-4700", "HP-4710" (naphthalene-type tetrafunctional epoxy resin), and "N-690" (cresol novolac) manufactured by DIC. type epoxy resin), “N-695” (cresol novolac type epoxy resin), “HP-7200”, “HP-7200HH”, “HP-7200H” (dicyclopentadiene type epoxy resin), “EXA-7311” ", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthylene ether type epoxy resin); “EPPN-502H” (trisphenol-type epoxy resin), “NC7000L” (naphthol novolak-type epoxy resin), “NC3000H”, “NC3000”, “NC3000L”, and “NC3100” (biphenyl-type epoxy resin) manufactured by Nihon Kayaku Co., Ltd. profit); “ESN475V” (naphthalene-type epoxy resin) and “ESN485” (naphthol novolak-type epoxy resin) manufactured by Nippon Tetsu Sumikin Chemical Co., Ltd.; “YX4000H”, “YL6121” (biphenyl-type epoxy resin), “YX4000HK” (bixylenol-type epoxy resin), and “YX8800” (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; “PG-100” and “CG-500” manufactured by Osaka Gas Chemicals, “YL7760” (bisphenol AF type epoxy resin), “YL7800” (fluorene type epoxy resin), and “jER1010” (solid phase) manufactured by Mitsubishi Chemical. Bisphenol A type epoxy resin), "jER1031S" (tetraphenylethane type epoxy resin), etc. are mentioned. These may be used individually or in combination of two or more types.

(C) When a liquid epoxy resin and a solid epoxy resin are used together as the component, their amount ratio (liquid epoxy resin:solid epoxy resin) is preferably 1:0.1 to 1:4 in mass ratio, more preferably 1. :0.3 to 1:3.5, more preferably 1:0.6 to 1:3. When the ratio of the liquid epoxy resin and the solid epoxy resin is within this range, the desired effect of the present invention can be significantly achieved.

The epoxy equivalent of the epoxy resin as component (C) is preferably 50 to 5000, more preferably 50 to 3000, further preferably 80 to 2000, and even more preferably 110 to 1000. By falling within this range, the crosslinking density of the cured product becomes sufficient and a magnetic layer with small surface roughness can be formed. In addition, the epoxy equivalent can be measured according to JIS K7236, and is the mass of the resin containing 1 equivalent of an epoxy group.

The weight average molecular weight of the epoxy resin as component (C) is preferably 100 to 5000, more preferably 250 to 3000, and still more preferably 400 to 1500. Here, the weight average molecular weight of the epoxy resin is the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

As the active ester resin, a resin having one or more active ester groups per molecule can be used. Among them, active ester resins include those having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. Resin is preferred. The active ester resin is preferably obtained by a condensation reaction of a carboxylic acid compound and/or a thiocarboxylic acid compound with a hydroxy compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, active ester resins obtained from carboxylic acid compounds and hydroxy compounds are preferable, and active ester resins obtained from carboxylic acid compounds, phenol compounds, and/or naphthol compounds are more preferable.

Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid.

Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m- Cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, Trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucine, benzenetriol, dicyclopentadiene type diphenol compound, phenol novolak, etc. are mentioned. Here, “dicyclopentadiene-type diphenol compound” refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

Preferred specific examples of the active ester resin include an active ester resin containing a dicyclopentadiene type diphenol structure, an active ester resin containing a naphthalene structure, an active ester resin containing an acetylated product of phenol novolak, and phenol and an active ester-based resin containing benzoylate of novolac. Among these, active ester resins containing a naphthalene structure and active ester resins containing a dicyclopentadiene type diphenol structure are more preferable. “Dicyclopentadiene-type diphenol structure” refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

Commercially available active ester resins include active ester resins containing a dicyclopentadiene type diphenol structure, such as "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", and "HPC-8000H-" 65TM”, “EXB-8000L-65TM” (manufactured by DIC); Examples of active ester resins containing a naphthalene structure include “EXB9416-70BK” and “EXB-8150-65T” (manufactured by DIC); As an active ester resin containing an acetylated product of phenol novolak, "DC808" (manufactured by Mitsubishi Chemical Corporation); Examples of the active ester resin containing the benzoylate of phenol novolak include "YLH1026" (manufactured by Mitsubishi Chemical Corporation); Examples of the active ester resin, which is an acetylated product of phenol novolak, include "DC808" (manufactured by Mitsubishi Chemical Corporation); Examples of active ester resins that are benzoylates of phenol novolak include "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), and "YLH1048" (manufactured by Mitsubishi Chemical Corporation); etc. can be mentioned.

Phenol-based resins and naphthol-based resins preferably have a novolac structure from the viewpoint of heat resistance and water resistance. Furthermore, from the viewpoint of adhesion to the conductor layer, a nitrogen-containing phenol-based curing agent is preferable, and a triazine skeleton-containing phenolic resin is more preferable.

Specific examples of phenol-based resins and naphthol-based resins include, for example, “MEH-7700”, “MEH-7810”, and “MEH-7851” manufactured by Meiwa Kasei Co., Ltd., “NHN” and “CBN” manufactured by Nihon Kayaku Co., Ltd. ”, “GPH”, “SN170”, “SN180”, “SN190”, “SN475”, “SN485”, “SN495”, “SN-495V”, “SN375”, “SN395” manufactured by Shin-Nittetsu Sumikin Kagaku Corporation. ", "TD-2090", "LA-7052", "LA-7054", "LA-1356", "LA-3018-50P", and "EXB-9500" manufactured by DIC Corporation.

Specific examples of the benzoxazine-based resin include "JBZ-OD100" (benzoxazine ring equivalent weight 218), "JBZ-OP100D" (benzoxazine ring equivalent weight 218), and "ODA-BOZ" (benzoxazine ring equivalent weight 218) manufactured by JFE Chemicals. ); “P-d” (benzoxazine ring equivalent 217) and “F-a” (benzoxazine ring equivalent 217) manufactured by Shikoku Kasei Kogyo Co., Ltd.; and "HFB2006M" (benzoxazine ring equivalent 432) manufactured by Showa Kobunshi Corporation.

Examples of the cyanate ester resin include bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylenecyanate), and 4,4'-methylenebis(2,6- dimethylphenylcyanate), 4,4'-ethylidenediphenyldicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4- Cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanate) Bifunctional cyanate resins such as natephenyl)thioether and bis(4-cyanatephenyl)ether; Polyfunctional cyanate resins derived from phenol novolac, cresol novolac, etc.; Prepolymers in which these cyanate resins are partially triazinated; etc. can be mentioned. Specific examples of cyanate ester resin include "PT30" and "PT60" (phenol novolak-type polyfunctional cyanate ester resin), "ULL-950S" (polyfunctional cyanate ester resin), and "BA230" manufactured by Lonza Japan Co., Ltd. ", "BA230S75" (a prepolymer in which part or all of bisphenol A dicyanate is triazylated and becomes a trimer), etc.

Specific examples of carbodiimide-based resins include Carbodilite (registered trademark) V-03 (carbodiimide group equivalent: 216), V-05 (carbodiimide group equivalent: 262), and V-07 manufactured by Nisshinbo Chemical Co., Ltd. (carbodiimide group equivalent: 200); V-09 (carbodiimide group equivalent: 200); and Stabaxol (registered trademark) P (carbodiimide group equivalent: 302) manufactured by Rhein Chemis.

Examples of the amine-based resin include resins having one or more amino groups per molecule, and examples include aliphatic amines, polyether amines, alicyclic amines, and aromatic amines. Among these, the desired resins of the present invention include From the viewpoint of demonstrating effectiveness, aromatic amines are preferable. The amine resin is preferably a primary amine or a secondary amine, and is more preferably a primary amine. Specific examples of amine-based curing agents include 4,4'-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfone, 4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenylsulfone. , 3,3'-diaminodiphenyl sulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4, 4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis (3-amino-4-hydroxyphenyl ) Propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis (4-aminophenyl) propane, 2,2-bis (4- (4-amino Phenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4 , 4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, etc. . Commercially available amine resins may be used, for example, "KAYABOND C-200S", "KAYABOND C-100", "Kayahard A-A", "Kayahard A-B", and "Kayahard A-S" manufactured by Nihon Kayaku Co., Ltd. , “Epicure W” manufactured by Mitsubishi Chemical Corporation, etc.

Examples of the acid anhydride-based resin include resins having one or more acid anhydride groups in one molecule. Specific examples of acid anhydride resin include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, and trialkyltetrahydrophthalic anhydride. , dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, trimellitic anhydride, pyromellitic anhydride. , Benzophenone tetracarboxylic acid dianhydride, biphenyltetracarboxylic acid dianhydride, naphthalenetetracarboxylic acid dianhydride, oxydiphthalic acid dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 1,3,3a ,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis( Anhydrotrimellitate) and polymeric acid anhydrides such as styrene-maleic acid resin copolymerized with styrene and maleic acid.

(C) When containing an epoxy resin and a curing agent as components, the amount ratio of the epoxy resin and all curing agents is a ratio of [total number of epoxy groups of the epoxy resin]:[total number of reactive groups of the curing agent], and is 1:0.01 to 1:0.01. The range of 1:5 is preferable, 1:0.5 to 1:3 is more preferable, and 1:1 to 1:2 is still more preferable. Here, the “epoxy group number of the epoxy resin” is the sum of the mass of the non-volatile component of the epoxy resin present in the first resin composition divided by the epoxy equivalent. In addition, the “number of active groups of the curing agent” is a value obtained by dividing the mass of the non-volatile component of the curing agent present in the first resin composition by the active group equivalent.

- Thermoplastic resin -

The weight average molecular weight of the thermoplastic resin in terms of polystyrene is preferably 30,000 or more, more preferably 50,000 or more, and even more preferably 100,000 or more. Furthermore, it is preferably 1 million or less, more preferably 750,000 or less, and even more preferably 500,000 or less. The weight average molecular weight of the thermoplastic resin in terms of polystyrene is measured by gel permeation chromatography (GPC). Specifically, the weight average molecular weight of the thermoplastic resin in terms of polystyrene was measured using "LC-9A/RID-6A" manufactured by Shimadzu Seisakusho as a measuring device and "Shodex K-800P/K-804L" manufactured by Showa Denko Corporation as a column. /K-804L” can be calculated using chloroform or the like as a mobile phase, measuring the column temperature at 40°C, and using a standard polystyrene calibration curve.

Examples of the phenoxy resin include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetophenone skeleton, novolak skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, and naphthalene skeleton. , a phenoxy resin having at least one skeleton selected from the group consisting of anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be a functional group such as a phenolic hydroxyl group or an epoxy group. Phenoxy resins may be used individually, or two or more types may be used in combination. Specific examples of phenoxy resins include "1256" and "4250" (both phenoxy resins containing a bisphenol A skeleton), "YX8100" (phenoxy resins containing a bisphenol S skeleton), and "YX6954" (bisphenol acetate) manufactured by Mitsubishi Chemical Corporation. phenoxy resin containing a phenone skeleton), and in addition, "FX280" and "FX293" manufactured by Shin-Niptetsu Sumikin Chemical Co., Ltd., and "YL7500BH30", "YX6954BH30", "YX7553", and "YX7553BH30" manufactured by Mitsubishi Chemical Co., Ltd. ", "YL7769BH30", "YL6794", "YL7213", "YL7290", and "YL7482".

As the acrylic resin, from the viewpoint of further lowering the thermal expansion coefficient and elastic modulus, acrylic resins containing functional groups are preferable, and acrylic resins containing epoxy groups with a glass transition temperature of 25°C or lower are more preferable.

The number average molecular weight (Mn) of the functional group-containing acrylic resin is preferably 10,000 to 1,000,000, and more preferably 30,000 to 900,000.

The functional group equivalent of the functional group-containing acrylic resin is preferably 1,000 to 50,000, and more preferably 2,500 to 30,000.

As the epoxy group-containing acrylic resin with a glass transition temperature of 25°C or lower, an epoxy group-containing acrylic acid ester copolymer resin with a glass transition temperature of 25°C or lower is preferable, and a specific example thereof is “SG-80H” (epoxy group-containing) manufactured by Nagase Chemtex. Acrylic acid ester copolymer resin (number average molecular weight Mn: 350000 g/mol, epoxy value 0.07 eq/kg, glass transition temperature 11°C)), “SG-P3” manufactured by Nagase Chemtex Corporation (epoxy group-containing acrylic acid ester copolymer resin (water) Average molecular weight Mn: 850000g/mol, epoxy content 0.21eq/kg, glass transition temperature 12°C).

Specific examples of polyvinyl acetal resin and butyral resin include inverter butyral “4000-2”, “5000-A”, “6000-C”, “6000-EP” manufactured by Denki Chemical Co., Ltd. Examples include the S-Lec BH series, BX series, KS series such as "KS-1", BL series such as "BL-1", and BM series manufactured by Kisui Kagaku Kogyoso.

Specific examples of the polyimide resin include “Licca Coat SN20” and “Licca Coat PN20” manufactured by Nippon Rika Co., Ltd. Specific examples of polyimide resins include linear polyimides obtained by reacting bifunctional hydroxyl group-terminated polybutadiene, diisocyanate compounds, and tetrabasic acid anhydrides (polyimides described in Japanese Patent Application Laid-Open No. 2006-37083), and polysiloxane. Modified polyimides such as skeleton-containing polyimides (polyimides described in Japanese Patent Application Laid-Open No. 2002-12667 and Japanese Patent Application Laid-Open No. 2000-319386, etc.) can be mentioned.

Specific examples of polyamidoimide resin include “Viromax HR11NN” and “Viromax HR16NN” manufactured by Toyobo Co., Ltd. Specific examples of polyamideimide resins include modified polyamideimides such as "KS9100" and "KS9300" (polyamideimide containing a polysiloxane skeleton) manufactured by Hitachi Kasei Kogyo Co., Ltd.

Specific examples of the polyethersulfone resin include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd. Specific examples of the polyphenylene ether resin include the oligophenylene ether-styrene resin "OPE-2St 1200" having a vinyl group manufactured by Mitsubishi Gas Chemical Co., Ltd.

Specific examples of polysulfone resins include polysulfone “P1700” and “P3500” manufactured by Solvay Advanced Polymers.

Among them, the thermoplastic resin is preferably at least one selected from phenoxy resin, polyvinyl acetal resin, butyral resin, and acrylic resin with a weight average molecular weight of 30,000 to 1,000,000.

(C) The content of the binder resin is preferably 1% by mass or more, more preferably 3% by mass, when the non-volatile component in the magnetic paste is 100% by mass, from the viewpoint of obtaining a magnetic layer showing good mechanical strength and insulation reliability. or more, more preferably 5% by mass or more. The upper limit is not particularly limited as long as the effect of the present invention is achieved, but is preferably 30 mass% or less, more preferably 25 mass% or less, and still more preferably 20 mass% or less.

In the magnetic paste of the present invention, the resin exudation of the binder resin (C) is suppressed by containing (B) the organic layered silicate mineral. When the non-volatile component in the magnetic paste is set to 100 mass%, the content of component (B) is set to B1, and the content of component (C) when the non-volatile component in the magnetic paste is set to 100 mass% is set to C1. , from the viewpoint of shape maintenance and handleability after printing, C1/B1 is preferably 1 or more, more preferably 3 or more, and even more preferably 5 or more. The upper limit is preferably 30 or less, more preferably 25 or less, and even more preferably 20 or less.

<(D) Curing accelerator>

The magnetic paste may further contain (D) a curing accelerator as an optional component.

Examples of the curing accelerator include amine-based curing accelerators, imidazole-based curing accelerators, phosphorus-based curing accelerators, guanidine-based curing accelerators, and metal-based curing accelerators. From the viewpoint of reducing the viscosity of the magnetic paste, the curing accelerator is preferably an amine-based curing accelerator or an imidazole-based curing accelerator. The curing accelerator may be used individually, or two or more types may be used in combination.

Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8. -Diazabicyclo(5,4,0)-undecene, etc. are mentioned, and 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene are preferable.

As the amine-based curing accelerator, commercially available products may be used, for example, "PN-50", "PN-23", and "MY-25" manufactured by Ajinomoto Fine Techno Co., Ltd.

Examples of imidazole-based curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, and 2-ethyl-4-methyl. Imidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methyl Midazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl -4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium Trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecyl imidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s- Triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazineisocyanuric acid adduct, 2-phenylimidazoleisocyanuric acid addition Water, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2 -a] imidazole compounds such as benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, imidazole compounds, and epoxy resins Adduct forms include, and 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole are preferable.

As the imidazole-based curing accelerator, a commercial product may be used, and examples include "2PHZ-PW" manufactured by Shikoku Kasei Kogyo Co., Ltd. and "P200-H50" manufactured by Mitsubishi Chemical Corporation.

Examples of phosphorus-based curing accelerators include triphenylphosphine, phosphonium borate compound, tetraphenylphosphonium tetraphenyl borate, n-butylphosphonium tetraphenyl borate, tetrabutylphosphonium decanoate, and (4-methylphenyl)triphenyl. Examples include phosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, and triphenylphosphine and tetrabutylphosphonium decanoate are preferred.

Examples of guanidine-based curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, and diphenylguanidine. , trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]deca-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0] Deca-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1, 1-diethyl biguanide, 1-cyclohexyl biguanide, 1-allyl biguanide, 1-phenyl biguanide, 1-(o-tolyl) biguanide, etc., dicyandiamide, 1,5,7-triazabicyclo[4.4.0]deca-5-ene is preferred.

Examples of the metal-based curing accelerator include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organic cobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organic copper complexes such as copper (II) acetylacetonate, and zinc (II) acetylacetonate. Organic zinc complexes, organic iron complexes such as iron(III) acetylacetonate, organic nickel complexes such as nickel(II) acetylacetonate, and organic manganese complexes such as manganese(II) acetylacetonate. Examples of organometallic salts include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

(D) From the viewpoint of obtaining the desired effect of the present invention, the curing accelerator is preferably at least one selected from acid anhydride-based epoxy resin curing agents, amine-based curing accelerators, and imidazole-based curing accelerators, and is preferably an amine-based curing accelerator, and at least one selected from imidazole-based curing accelerators.

(D) The content of the curing accelerator is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, when the non-volatile component in the magnetic paste is 100% by mass, from the viewpoint of lowering the viscosity of the magnetic paste. Preferably it is 0.5 mass% or more, and the upper limit is preferably 5 mass% or less, more preferably 3 mass% or less, and even more preferably 1 mass% or less.

<(E) Dispersant>

The magnetic paste may further contain (E) a dispersant as an optional component.

(E) Examples of the dispersant include phosphoric acid ester-based dispersants such as polyoxyethylene alkyl ether phosphoric acid; Anionic dispersants such as sodium dodecylbenzelsulfonate, sodium laurate, and ammonium salt of polyoxyethylene alkyl ether sulfate; Organosiloxane-based dispersants, acetylene glycol, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide, etc. A thermophilic dispersant, etc. can be mentioned. Among these, anionic dispersants are preferable. Dispersants may be used individually, or two or more types may be used in combination.

A commercially available product can be used as the phosphoric acid ester-based dispersant. Examples of commercial products include "RS-410", "RS-610", and "RS-710" of the "Phospherol" series manufactured by Toho Chemical Industries, Ltd.

Examples of the organosiloxane-based dispersant include commercially available products such as "BYK347" and "BYK348" manufactured by Big Chemistry.

As a polyoxyalkylene-based dispersant, commercially available products include "AKM-0531", "AFB-1521", "SC-0505K", "SC-1015F", and "SC-0708A" of the "Mariarim" series manufactured by Nichiyu Corporation, and “HKM-50A” etc. can be mentioned.

Acetylene glycol is commercially available from Air Products and Chemicals Inc. Examples include “82,” “104,” “440,” “465,” and “485” from the “Safinol” series, and “Olefin Y.”

(E) The content of the dispersant is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, when the non-volatile component in the magnetic paste is 100% by mass, from the viewpoint of significantly exhibiting the effect of the present invention. , more preferably 0.5 mass% or more, and the upper limit is preferably 5 mass% or less, more preferably 3 mass% or less, and even more preferably 1 mass% or less.

<(F) Other additives>

The magnetic paste may further contain (F) other additives as needed. Examples of such other additives include, for example, a curing retardant such as triethyl borate to improve pot life, an inorganic filler (however, magnetic powder or organic layered silicate minerals), flame retardants, organic fillers, organometallic compounds such as organic copper compounds, organic zinc compounds, and organic cobalt compounds, and thickeners, antifoaming agents, leveling agents, adhesion imparting agents, and colorants. Resin additives such as these can be mentioned.

The content of the solvent contained in the above-mentioned magnetic paste is preferably less than 1.0 mass%, more preferably 0.8 mass% or less, further preferably 0.5 mass% or less, especially preferably It is 0.1 mass% or less. The lower limit is not particularly limited, but is 0.001% by mass or more or does not contain it. The viscosity of the magnetic paste can be lowered even if it does not contain a solvent. By reducing the amount of solvent in the magnetic paste, the generation of voids due to volatilization of the solvent can be suppressed, and adaptation to vacuum printing is also possible.

<Method for producing magnetic paste>

Magnetic paste can be produced, for example, by a method of stirring the blended ingredients using a stirring device such as a three-roll roll or rotary mixer.

<Physical properties of magnetic paste, etc.>

FIG. 2 is a cross-sectional view schematically showing an example of the cross-section of the magnetic layer 120 formed on the substrate 110. As shown in FIG. 2, when magnetic paste (not shown) is printed on the substrate 110 and cured to form the magnetic layer 120, a portion of the resin is extruded from the edge portion 120E of the magnetic layer 120. In some cases, the salted-out portion 130 is formed. When the above-mentioned magnetic paste is used, exudation of resin can be suppressed. Therefore, the flow distance (L) of the salted resin can be shortened. For example, a cured product obtained by thermosetting a magnetic paste (for example, a cured product obtained by thermosetting at 150°C for 60 minutes) exhibits the characteristic that resin bleeding after screen printing is suppressed. Specifically, the magnetic paste is screen-printed on a printed board, and after printing, it is thermally cured at 150°C for 60 minutes to obtain an evaluation board. The maximum flow distance of the resin dyed from the printed pattern end of this evaluation substrate is preferably 500 μm or less, more preferably 480 μm or less, and still more preferably 450 μm or less. Additionally, the lower limit may be 0.001 μm or more. Since a cured product having such a high relative magnetic permeability can be obtained, the above-described magnetic paste can be used as a magnetic paste for forming an inductor element.

The magnetic paste may contain a solvent, but even if it does not contain a solvent, it is preferably in the form of a paste at an appropriate temperature. Specifically, from the viewpoint of printability, the viscosity of the magnetic paste is usually 20 Pa·s or more, preferably 30 Pa·s or more, more preferably 50 Pa·s or more, even more preferably 60 Pa·s or more, at 25°C. Particularly preferably, it is 70 Pa·s or more, and from the viewpoint of printability and ease of removal of air bubbles during printing, it is usually 200 Pa·s or less, preferably 190 Pa·s or less, and more preferably 180 Pa·s or less. Viscosity can be measured using an E-type viscometer while maintaining the temperature of the magnetic paste at 25 ± 2°C.

A cured product obtained by thermosetting magnetic paste (for example, a cured product obtained by thermal curing at 180° C. for 90 minutes) generally exhibits the characteristic of high relative magnetic permeability at a frequency of 100 MHz. For example, a sheet-shaped magnetic paste is heat-cured at 180°C for 90 minutes to obtain a sheet-shaped cured product. The relative permeability of this cured product at a frequency of 100 MHz is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. Additionally, the upper limit can usually be 20 or less.

A cured product obtained by thermosetting magnetic paste (for example, a cured product obtained by thermal curing at 180° C. for 90 minutes) generally exhibits the characteristic of low magnetic loss at a frequency of 100 MHz. For example, a sheet-shaped magnetic paste is heat-cured at 180°C for 90 minutes to obtain a sheet-shaped cured product. The magnetic loss of this cured product at a frequency of 100 MHz is preferably 0.5 or less, more preferably 0.4 or less, and even more preferably 0.3 or less. Additionally, the lower limit can usually be 0.001 or more.

[Inductor element]

The inductor element of the present invention includes a magnetic layer that is a cured product of the magnetic paste of the present invention. Here, the inductor element includes not only an inductor element as an electronic component but also an inductor element included in a circuit board. 1 is a schematic plan view of an inductor element according to an embodiment of the present invention. The inductor element 1 includes a substrate 11, a magnetic layer 12, and a wiring 13 formed of a conductor. The wiring 13 is covered with the magnetic layer 12 and the wiring 13 is formed in a vortex shape with the core portion 14 as the center. Additionally, the core portion 14 has a magnetic layer 12 embedded therein.

The magnetic layer 12 is a cured product of the magnetic paste of the present invention. Since the magnetic layer 12 is a cured product of magnetic paste, the resin exudation property of the magnetic layer 12 is suppressed. For this reason, the wiring 13 can be formed with a short distance between the wirings. Hereinafter, the inductor element and its manufacturing method will be described through the inductor element manufacturing method.

The manufacturing method of the inductor element is,

(1) A process of printing magnetic paste on a substrate and thermosetting the magnetic paste to form a first magnetic layer,

(2) a process of forming wiring on the first magnetic layer,

(3) a process of printing magnetic paste on the first magnetic layer, core portion, and wiring, and thermosetting the magnetic paste to form a second magnetic layer;

Includes. Here, the magnetic layer 12 includes first and second magnetic layers.

<Process (1)>

In step (1), magnetic paste is printed on a substrate and the magnetic paste is thermoset to form a first magnetic layer. In performing step (1), a step of preparing magnetic paste may be included. The magnetic paste is as described above.

The substrate is usually an insulating substrate. Examples of substrate materials include insulating substrates such as glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The substrate may be an inner layer circuit board with wiring etc. inserted within its thickness.

Examples of the substrate include, for example, a wiring board made into a conductor layer by etching the copper layer using "R1515E" manufactured by Panasonic Corporation, which is a glass cloth-based epoxy resin double-sided copper-clad laminate.

The magnetic paste is applied on the substrate by full-body printing or pattern printing. As a printing method, screen printing is usually performed, but other printing methods may be adopted. After application, it is thermally cured to obtain a first magnetic layer.

The thermal curing conditions of the magnetic paste vary depending on the composition and type of the magnetic paste, but the curing temperature is preferably 120°C or higher, more preferably 130°C or higher, even more preferably 150°C or higher, and preferably 240°C or higher. ℃ or lower, more preferably 220 ℃ or lower, even more preferably 200 ℃ or lower. The curing time of the magnetic paste is preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 15 minutes or more, preferably 120 minutes or less, more preferably 100 minutes or less, even more preferably It is less than 90 minutes.

Before thermally curing the magnetic paste, a preliminary heat treatment of heating the magnetic paste at a temperature lower than the curing temperature may be performed. The temperature of the preliminary heat treatment is preferably 50°C or higher, preferably 60°C or higher, more preferably 70°C or higher, preferably lower than 120°C, preferably 110°C or lower, and more preferably 100°C or lower. . The time for the preliminary heat treatment is usually preferably 5 minutes or more, more preferably 15 minutes or more, preferably 150 minutes or less, and more preferably 120 minutes or less.

<Process (2)>

In step (2), wiring is formed on the first magnetic layer formed in step (1). Methods for forming wiring include, for example, a plating method, a spur method, and a vapor deposition method, and among them, the plating method is preferable. In a preferred embodiment, the surface of the first magnetic layer is plated by an appropriate method such as a semi-additive method or a full additive method to form a wiring having a swirl-like wiring pattern.

Materials for wiring include, for example, simple metals such as gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium; An alloy of two or more metals selected from the group of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium. Among them, from the viewpoint of versatility, cost, ease of patterning, etc., it is preferable to use chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel-chromium alloy, copper-nickel alloy, or copper-titanium alloy. It is more preferable to use chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or a nickel-chromium alloy, and even more preferably to use copper.

Here, an example of an embodiment in which wiring is formed on the first magnetic layer will be described in detail. A plating seed layer is formed on the surface of the first magnetic layer by electroless plating. Next, an electrolytic plating layer is formed on the formed plating seed layer by electrolytic plating, and if necessary, the unnecessary plating seed layer is removed through a process such as etching, so that a wiring having a desired wiring pattern can be formed. After forming the wiring, annealing treatment may be performed as needed for purposes such as improving the peeling strength of the wiring. Annealing treatment can be performed, for example, by heating the substrate at 150 to 200°C for 20 to 90 minutes.

After forming the wiring, a mask pattern exposing a portion of the plating seed layer is formed on the formed plating seed layer, corresponding to the swirl pattern. In this case, after forming an electrolytic plating layer by electrolytic plating on the exposed plating seed layer, the mask pattern is removed. Thereafter, the unnecessary plating seed layer is removed through a process such as etching, and a wiring having a desired pattern is formed.

From the viewpoint of thinning, the thickness of the wiring is preferably 70 μm or less, more preferably 60 μm or less, further preferably 50 μm or less, even more preferably 40 μm or less, particularly preferably 30 μm or less, 20 μm or less, It is 15μm or less or 10μm or less. The lower limit is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more.

<Process (3)>

In step (3), magnetic paste is printed on the first magnetic layer, core portion, and wiring, and the magnetic paste is thermoset to form a second magnetic layer. The method of forming the second magnetic layer is the same as that of the first magnetic layer. The magnetic paste that forms the first magnetic layer and the magnetic paste that forms the second magnetic layer may be the same or different.

After step (1), a step of forming an insulating layer on the first magnetic layer may be provided. Additionally, after step (2), a step of forming an insulating layer on the wiring may be provided. The insulating layer may be formed in the same way as the insulating layer of the printed wiring board, or may be made of the same material as the insulating layer of the printed wiring board.

[Circuit board]

The circuit board includes the inductor element of the present invention. The circuit board can be used as a wiring board for mounting electronic components such as semiconductor chips, and can also be used as a (multilayer) printed wiring board using such a wiring board as an inner layer board. Moreover, such a wiring board can be used as a chip inductor component divided into individual pieces, and it can also be used as a printed wiring board on which the chip inductor component is surface mounted.

Additionally, various types of semiconductor devices can be manufactured using this wiring board. Semiconductor devices including such wiring boards are suitable for electrical appliances (e.g., computers, mobile phones, digital cameras, televisions, etc.) and vehicles (e.g., motorcycles, automobiles, trams, ships, aircraft, etc.). You can use it.

Example

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In addition, in the following description, “part” and “%” indicating quantity mean “part by mass” and “% by mass”, respectively, unless otherwise specified.

<Example 1>

10 parts by mass of epoxy resin (“ZX-1059”, a mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin, manufactured by Nippon Tetsu Sumikin Chemical Co., Ltd.), 10 parts by mass of epoxy resin (“ED-523T”, low-viscosity epoxy resin, 5 parts by mass of dispersant (“RS-710”, polymer anionic dispersant, manufactured by Toho Chemicals), 1 part by mass of curing accelerator (“2P4MZ”, imidazole-based curing accelerator, manufactured by Shikoku Kasei) , 100 parts by mass of magnetic powder (“M05S,” Fe-Mn-based ferrite, average particle diameter, 3 μm, manufactured by Powder Tech Co., Ltd.), organic smectite (“Smectone STN,” trioctylmethylammonium-treated hectorite, manufactured by Kunimine Kogyo Co., Ltd. ) 2 parts by mass were mixed and uniformly dispersed with 3 rolls to prepare a magnetic paste.

<Example 2>

In Example 1, the amount of organic smectite (“Smectone STN”, trioctylmethylammonium-treated hectorite, manufactured by Kunimine Kogyo Co., Ltd.) was changed from 2 parts by mass to 1.5 parts by mass. A magnetic paste was prepared in the same manner as in Example 1 except for the above.

<Example 3>

In Example 1, the amount of organic smectite (“Smectone STN”, trioctylmethylammonium-treated hectorite, manufactured by Kunimine Kogyo Co., Ltd.) was changed from 2 parts by mass to 1 part by mass. A magnetic paste was prepared in the same manner as in Example 1 except for the above.

<Example 4>

In Example 1, 100 parts by mass of magnetic powder (“M05S”, Fe-Mn-based ferrite, average particle diameter 3 μm, manufactured by Powder Tech) was mixed with magnetic powder (“AW2-08PF3F”, Fe-Cr-Si-based alloy (amorphous ), average particle diameter 3.0 μm, manufactured by Epson Atmix) was changed to 100 parts by mass. A magnetic paste was prepared in the same manner as in Example 1 except for the above.

<Example 5>

In Example 1, 2 parts by mass of organic smectite (“Smectone STN”, trioctylmethylammonium treated hectorite, manufactured by Kunimine Kogyo) was mixed with organic smectite (“Smectone SAN”, dimethyldistearylammonium treated hectorite, (manufactured by Kunimine Kogyo) was changed to 2 parts by mass. A magnetic paste was prepared in the same manner as in Example 1 except for the above.

<Example 6>

In Example 1, 2 parts by mass of organic smectite (“Smectone STN”, trioctylmethylammonium treated hectorite, manufactured by Kunimine Kogyo) was mixed with organic montmorillonite (“Orben M”, dimethyldioctadecylammonium treated montmorillonite, Shiraishi). (manufactured by Kogyo) was changed to 2 parts by mass. A magnetic paste was prepared in the same manner as in Example 1 except for the above.

<Comparative Example 1>

In Example 1, 2 parts by mass of organic smectite (“Smectone STN,” trioctylmethylammonium-treated hectorite, manufactured by Kunimine Kogyo Co., Ltd.) was not used. A magnetic paste was prepared in the same manner as in Example 1 except for the above.

<Comparative Example 2>

In Example 1, 2 parts by mass of organic smectite (“Smectone STN”, trioctylmethylammonium treated hectorite, manufactured by Kunimine Kogyo) was mixed with non-organized smectite (“Smectone SWN”, hectorite, Kunimine Kogyo). (manufactured by Teacher) was changed to 1 part by mass. A magnetic paste was prepared in the same manner as in Example 1 except for the above.

<Comparative Example 3>

In Example 1, 2 parts by mass of organic smectite (“Smectone STN,” trioctylmethylammonium-treated hectorite, manufactured by Kunimine Kogyo Co., Ltd.) was replaced with 1 part by mass of hydrophobic fumed silica (AEROSIL RY200, manufactured by Japan Aerosil Corporation). A magnetic paste was prepared in the same manner as in Example 1 except for the above.

<Measurement of viscosity of magnetic paste>

The temperature of the magnetic paste of each example and each comparative example was maintained at 25 ± 2°C, and an E-type viscometer (“RE-80U” manufactured by Toki Sangyo Co., Ltd., 3°×R9.7 cone, rotation speed: 5 rpm) was used. Viscosity was also measured. Additionally, the measured viscosity was evaluated based on the following criteria from the viewpoint of printability and ease of removing air bubbles.

○: 20Pa·s or more but less than 200Pa·s

×: Less than 20Pa·s or more than 200Pa·s

<Measurement of resin exudability after screen printing>

(1) Fabrication of printed evaluation board

As a printed board, both sides of a glass cloth-based epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.8 mm, R5715E manufactured by Matsushita Denko Co., Ltd.) were etched 1 μm with a micro-etchant (CZ8100 manufactured by Meksa Co., Ltd.) to roughen the copper surface. prepared for what was done. As a printing member, a metal mask (plate SUS304, aperture method laser, no surface treatment, mask thickness 40 μm, rectangular opening pattern 1 mm x 3 mm, manufactured by Process Lab Micron) was prepared, and additionally a metal squeegee (plate SUS304, squeegee thickness 0.25 mm, no surface treatment, manufactured by Takugiken Co., Ltd.) was prepared.

Printing was performed by tightly fixing the printed board and the printing member and sweeping the magnetic paste produced in each Example and each Comparative Example using a metal squeegee at an angle of 45 deg, a speed of 10 mm/sec, and a linear pressure of 6.5 N/cm. After printing, the printing member was separated and the magnetic paste was cured under curing conditions of 150°C for 60 minutes to produce a printed evaluation board.

(2) Evaluation of resin extrusion ability (resin exudation amount)

The edge portion of the 1 mm x 3 mm rectangular printed pattern of the produced printed evaluation board was photographed using a digital microscope (VHX-900, manufactured by Keyence), and the resin extruded from the printed evaluation board was observed. Among the flow distances of the resin exuded from the edge portion of the printed pattern, the maximum distance was measured as the resin exudability (resin exudability amount). Additionally, the resin exudability was evaluated based on the following criteria.

○: Resin exudation amount is less than 500μm

×: Resin dissolution amount is 500μm or more

<Measurement of relative magnetic permeability and magnetic loss>

As a support, a polyethylene terephthalate (PET) film (“PET501010” manufactured by Lintech, thickness 50 μm) treated with a silicone-based mold release agent was prepared. The magnetic paste produced in each example and each comparative example was uniformly applied with a doctor blade on the release surface of the PET film so that the thickness of the paste layer after drying was 100 μm, and a resin sheet was obtained. The obtained resin sheet was heated at 180°C for 90 minutes to thermoset the magnetic paste layer, and the support was peeled off to obtain a sheet-like cured product. The obtained cured product was cut into test pieces with a width of 5 mm and a length of 18 mm to serve as evaluation samples. This evaluation sample was measured using an Agilent Technologies ("HP8362B" manufactured by Agilent Technologies) using a 3-turn coil method with a measurement frequency of 100 MHz, and the relative permeability (μ') and magnetic loss (μ') at a room temperature of 23°C. ') was measured.

The results of Examples 1 to 6 and Comparative Examples 1 to 3 are shown in Table 1. From Examples 1 to 6, it was found that the magnetic paste of the present invention containing organic smectite significantly improved the resin exudation property. On the other hand, Comparative Example 1 did not contain organic smectite, and large resin exudation was observed. Additionally, as can be seen from Comparative Example 2, when unorganized smectite was used, the resin dissolution property was not improved. In Comparative Example 3, hydrophobic fumed silica, which is widely used as a thixotropy imparting agent, was added, but the resin extrusion property was not improved, and the viscosity increased, falling outside the desirable range from the viewpoints of printability and bubble removal.

1 inductor element
11 substrate
12 magnetic layer
13 wiring layer
14 core part
110 substrate
120 magnetic layer
Edge part of 120E magnetic layer
130 Excavation part
L flow distance

Claims (12)

(A) magnetic powder,
(B) Organized layered silicate minerals;
(C) binder resin, and
(E) comprising a dispersing agent,
(A) The content of component is 60% by mass or more when the non-volatile component in the magnetic paste is 100% by mass,
(B) The content of component is 0.1% by mass or more and 5% by mass or less when the non-volatile component in the magnetic paste is 100% by mass,
(C) The content of component is 1% by mass or more and 30% by mass or less when the non-volatile component in the magnetic paste is 100% by mass,
A magnetic paste for screen printing, where the viscosity of the magnetic paste is 50 Pa·s or more and 200 Pa·s or less at 25°C. The magnetic paste according to claim 1, wherein component (B) contains organic smectite. The magnetic paste according to claim 2, wherein component (B) contains smectite ion-exchanged with quaternary ammonium ions. The magnetic paste according to claim 1, wherein the component (B) is at least one selected from organic hectorite and organic montmorillonite. The magnetic paste according to claim 4, wherein the component (B) is at least one selected from hectorite ion-exchanged with quaternary ammonium ions and montmorillonite ion-exchanged with quaternary ammonium ions. The magnetic paste according to claim 1, wherein component (C) contains a thermosetting resin. The magnetic paste according to claim 1, wherein component (C) contains an epoxy resin. The magnetic paste according to claim 1, wherein the component (A) is at least one selected from iron oxide powder and iron alloy-based metal powder. The content of component (B) when the non-volatile component in the magnetic paste is set to 100 mass% is B1, and the content of component (C) when the non-volatile component in the magnetic paste is set to 100 mass% is A magnetic paste in which C1/B1 is 1 or more and 30 or less when the content is C1. An inductor element comprising a magnetic layer that is a cured product of the magnetic paste according to any one of claims 1 to 9. A circuit board comprising the inductor element according to claim 10. delete

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