JP6984755B2 - Magnetic paste - Google Patents

Description

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

Many inductor elements are installed in information terminals such as mobile phones and smartphones. In the past, independent inductor components were mounted on the board, but in recent years, a method of forming a coil by the conductor pattern of the board and providing an inductor element inside the board has been used.

As a method of providing an inductor element inside a substrate, for example, a method of screen-printing a paste material containing a magnetic material on a substrate including wiring to form a magnetic layer is known (Patent Document 1, Patent). See Document 2).

Japanese Unexamined Patent Publication No. 6-69058 Japanese Unexamined Patent Publication No. 2017-63100

The conventional paste material has a large resin exudation property. Therefore, when screen printing is performed using the paste material and cured to form the magnetic layer, a part of the resin component and the magnetic powder constituting the paste material exudes from the edge of the magnetic layer. Since it is difficult to form a conductor layer and install components on the part on the substrate where the exuded component is present, the degree of freedom in circuit design is reduced and the miniaturization of the circuit is hindered. Patent Document 1 and Patent Document 2 describe a method of suppressing resin seepage by improving the screen printing method or the structure of the inductor element. However, Patent Document 1 and Patent Document 2 describe. The method described in 2 was not always satisfactory.

The present invention has been made in view of the above circumstances, and provides a magnetic paste capable of obtaining a cured product having suppressed resin seepage, an inductor element using the magnetic paste, and a circuit board. With the goal.

As a result of diligent research to achieve the above object, the present inventor has found that the resin exudation property is suppressed by using a magnetic paste containing an organic layered silicate mineral, and the present invention has been made. Has been completed.

That is, the present invention includes the following contents.
[1] (A) Magnetic powder,
A magnetic paste containing (B) an organic layered silicate mineral and (C) a binder resin.
[2] The magnetic paste according to [1], wherein the component (B) contains an organicized smectite.
[3] The magnetic paste according to [2], wherein the component (B) contains smectite ion-exchanged with a quaternary ammonium ion.
[4] The magnetic paste according to any one of [1] to [3], wherein the component (B) is at least one selected from organicized hectorite and organicized montmorillonite.
[5] The magnetism 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. paste.
[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 component (A) is at least one selected from iron oxide powder and iron alloy-based metal powder.
[9] The content of the component (B) when the non-volatile component in the magnetic paste is 100% by mass is B1, and the content of the component (C) when the non-volatile component in the magnetic paste is 100% by mass. The magnetic paste according to any one of [1] to [8], wherein C1 / B1 is 1 or more and 30 or less when C1 is used.
[10] The magnetic paste according to any one of [1] to [9], which is used for forming an inductor element.
[11] An inductor element including a magnetic layer which is a cured product of the magnetic paste according to any one of [1] to [10].
[12] A circuit board including the inductor element according to [11].

According to the present invention, it is possible to provide a magnetic paste capable of obtaining a cured product in which the resin seepage property is suppressed, and an inductor element and a circuit board using the magnetic paste.

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

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that each drawing merely schematically shows the shape, size and arrangement of the components so that the invention can be understood. The present invention is not limited to the following embodiments, and each component can be appropriately modified. Further, the configuration according to the embodiment of the present invention is not always manufactured or used by the arrangement of the illustrated examples.

[Magnetic paste]
The magnetic paste of the present invention contains (A) magnetic powder, (B) organic layered silicate mineral, and (C) binder resin.

In the present invention, by containing (B) an organic layered silicate mineral, it is possible to obtain a cured product in which the resin exudation property is suppressed. Further, the obtained cured product can usually improve the relative magnetic permeability and reduce the magnetic loss in the frequency range of 10 to 200 MHz.

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

<(A) Magnetic powder>
The magnetic paste contains (A) magnetic powder. Examples of the 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. System ferrite, Ni-Zn system ferrite, Ba-Zn system ferrite, Ba-Mg system ferrite, Ba-Ni system ferrite, Ba-Co system ferrite, Ba-Ni-Co system ferrite, Y system ferrite, iron oxide powder (III) ), Iron oxide powder such as triiron tetroxide; Fe—Si alloy powder, Fe—Si—Al alloy powder, Fe—Cr alloy powder, Fe—Cr—Si alloy powder, Fe—Ni—Cr Alloy powder, Fe-Cr-Al alloy powder, Fe-Ni alloy powder, Fe-Ni-Mo alloy powder, Fe-Ni-Mo-Cu alloy powder, Fe-Co alloy powder, or Fe-Ni. -Iron alloy-based metal powder such as Co-based alloy powder; Amorphous alloys such as Co-based amorphous, and the like.

Among them, 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 a ferrite containing at least one selected from Ni, Cu, Mn, and Zn. The iron alloy-based metal powder is preferably an iron alloy-based metal powder containing at least one selected from Si, Cr, Al, Ni, and Co.

As the magnetic powder (A), a commercially available magnetic powder can be used. Specific examples of commercially available magnetic powders that can be used include "M05S" manufactured by Powder Tech Co., Ltd .; "PST-S" manufactured by Sanyo Special Steel Co., Ltd .; "AW2-08" and "AW2-08PF20F" manufactured by Epson Atmix Co., Ltd. "AW2-08PF10F", "AW2-08PF3F", "Fe-3.5Si-4.5CrPF20F", "Fe-50NiPF20F", "Fe-80Ni-4MoPF20F"; "LD-M", "LD" manufactured by JFE Chemical Co., Ltd. -MH "," KNI-106 "," KNI-106GSM "," KNI-106GS "," KNI-109 "," KNI-109GSM "," KNI-109GS ";" KNS-415 "manufactured by Toda Kogyo Co., Ltd., "BSF-547", "BSF-029", "BSN-125", "BSN-125", "BSN-714", "BSN-828", "S-1281", "S-1641", "S" -1651 "," S-1470 "," S-1511 "," S-2430 ";" JR09P2 "manufactured by Nippon Heavy Chemical Industries, Ltd .;" Nanotek "manufactured by CIK Nanotech Co., Ltd .;" JEMK-S "," JEMK-S "manufactured by Kinsei Matek Co., Ltd. "JEMK-H": "Ytrium iron oxide" manufactured by ALDRICH and the like can be mentioned. The magnetic powder may be used alone or in combination of two or more.

(A) The magnetic powder is preferably spherical. The value (aspect ratio) obtained by dividing the length of the major axis of the magnetic powder by the length of the minor axis is preferably 2 or less, more preferably 1.5 or less, still more preferably 1.2 or less. In general, it is easier to improve the relative permeability when the magnetic powder has a flat shape that is not spherical. However, it is usually preferable to use a spherical magnetic powder from the viewpoint of obtaining a paste having a preferable viscosity and which can reduce the magnetic loss.

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

(A) The average particle size of the magnetic powder can be measured by a laser diffraction / scattering method based on the Mie scattering theory. Specifically, it can be measured by creating a particle size distribution of the magnetic powder on a volume basis using a laser diffraction / scattering type particle size distribution measuring device and using the median diameter as the average particle size. As the measurement sample, a magnetic powder dispersed in water by ultrasonic waves can be preferably used. As the laser diffraction / scattering type particle size distribution measuring device, "LA-500" manufactured by HORIBA, Ltd., "SALD-2200" manufactured by Shimadzu Corporation, or the like can be used.

(A) a specific surface area of the magnetic powder, from the viewpoint of improving the relative permeability, preferably 0.05 m ² / g or more, more preferably 0.1 m ² / g or more, more preferably 0.3 m ² / g That is all. Further, it is preferably 10 m ² / g or less, more preferably 8 m ² / g or less, and further preferably 5 m ² / g or less. (A) The specific surface area of the magnetic powder can be measured by the BET method.

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

(A) The content (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 permeability and reducing the magnetic loss. , More preferably 65% by mass or more, still more preferably 70% by mass or more. Further, it is preferably 98% by mass or less, more preferably 96% by mass or less, and further preferably 94% by mass or less.
In the present invention, the content of each component in the magnetic paste is a value when the non-volatile component in the magnetic paste is 100% by mass, unless otherwise specified.

<(B) Organic layered silicate mineral>
The magnetic paste contains (B) an organic layered silicate mineral. (B) By containing the organicized layered silicate mineral in the magnetic paste, it becomes possible to obtain a cured product in which the resin exudation property is suppressed. Here, "organized" means "ion-exchanged with organic onium ions".

Layered silicate minerals are also commonly referred to as phyllosilicate minerals. Layered silicate minerals can be used alone or in combination of two or more. Further, as the layered silicate mineral, a natural product may be used or a synthetic product may be used. As the crystal structure of the layered silicate mineral, it is preferable to use one having a high degree of purity, which is regularly stacked in the c-axis direction. You may use it.

Examples of the layered silicate mineral include smectite, kaolinite, halloysite, talc, mica and the like. Among these, smectite is preferable from the viewpoint of obtaining a cured product capable of effectively suppressing resin exudation.

Smectites, the general _{formula: X 0.2~0.6 Y 2~3 Z 4 O} 10 (OH) 2 · nH 2 O ( provided that, X is K, Na, 1 / 2Ca, and the group consisting of 1 / 2Mg Y is one or more selected from the group consisting of Mg, Fe, Mn, Ni, Zn, Li, Al, and Cr, and Z is selected from the group consisting of Si and Al. 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.) Or it is synthesized. Examples of smectites include hectorite, montmorillonite, byderite, nontronite, saponite, iron saponite, saponite, stevensite, bentonite, or substitutions, derivatives thereof, or mixtures thereof. Among these, hectorite and montmorillonite are preferable from the viewpoint of obtaining a cured product capable of effectively suppressing resin exudation.

The organic onium ion represents 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 the component (B).

Examples of the organic onium ion include an organic ammonium ion, an organic phosphonium ion, an organic sulfonium ion, and an organic imidazolium ion. Of these, organic ammonium ions and organic phosphonium ions are preferable, and organic ammonium ions are particularly preferable, from the viewpoint of obtaining a cured product in which the resin seepage property is effectively suppressed.

Examples of the organic group contained in the organic onium ion include a monovalent hydrocarbon group such as an alkyl group, an alkenyl group, an aryl group and an aralkyl group; a hydroxyalkyl group; a carboxyalkyl group; a polyalkylene ether group; and the like. .. One type of these organic groups may be used, or two or more types may be used in combination. Of these, a monovalent hydrocarbon group and a polyalkylene ether group are preferable from the viewpoint of obtaining a cured product in which the resin seepage property 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. 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-mentioned preferable requirements, a cured product having a particularly small resin seepage property can be obtained.

Preferred examples of the monovalent hydrocarbon group are methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, t-butyl group, isobutyl group, n-pentyl group and isopentyl. Group, neopentyl 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. Can be mentioned.

The polyalkylene ether group represents a group represented by the following formula (I).
-(RO) _m- H (I)

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

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, nitrogen atom is preferable for ^{X 1} from the viewpoint of obtaining a cured product in which the resin exudation property is effectively suppressed.

In formula (II), R ¹ represents the organic group described above. Among the organic groups, those selected from the group consisting of a monovalent hydrocarbon group and a polyalkylene ether group are preferable from the viewpoint of obtaining a cured product in which the resin exudability is effectively suppressed, and an alkyl group or a polyalkylene ether is preferable. Groups are more preferred, alkyl groups are particularly preferred.

In formula (II), R ² , R ³ and R ⁴ each independently represent a group selected from the group consisting of a hydrogen atom and the organic group. Among the organic groups, those selected from the group consisting of a monovalent hydrocarbon group and a polyalkylene ether group are preferable from the viewpoint of obtaining a cured product in which the resin exudability is effectively suppressed, and an alkyl group or a polyalkylene ether is preferable. Groups are more preferred, alkyl groups are particularly preferred.

Among the organic onium ions, organic ammonium ions are preferable, secondary to quaternary organic ammonium ions are more preferable, and tertiary to quaternary organics are preferable from the viewpoint of obtaining a cured product in which the resin exudation property is effectively suppressed. Ammonium ions are more preferred, and quaternary organic ammonium ions are particularly preferred. Therefore, in the organic onium ion represented by Formula (II), of R ^2, R ³ and R ^4, preferably more than one is an organic group, more that two or more of an organic group It is preferable that all three are organic groups, and it is particularly preferable that all three are organic groups.

Among the quaternary ammonium ions represented by the formula (II), it is preferable that at least a part of ^{R 1} , R ² , R ³ and R ^{4 is a long-chain organic group.} Further, ^{it is more preferable that some of R 1} , R ² , R ³ and R ⁴ are long-chain organic groups and the rest are short-chain organic groups. ^{Of these, it is particularly preferable that 2 to 3 of} R ¹ , R 2, R 3 and R ⁴ are long-chain organic groups, and the remaining 1 to 2 are short-chain organic groups. The long-chain organic group usually represents an organic group having 8 or more carbon atoms, preferably 12 or more carbon atoms. The short-chain organic group represents an organic group having 1 to 7 carbon atoms. By using a quaternary ammonium ion that satisfies such a requirement, a cured product having a particularly small resin seepage property can be obtained, and the effect is particularly remarkable when the organic group is an alkyl group.

Preferred specific examples of the organic onium ion include trimethyloctylammonium ion, trimethyldecylammonium ion, trimethyldodecylammonium ion, trimethyltetradecylammonium ion, trimethylhexadecylammonium ion, trimethyloctadecylammonium ion, trimethylicosylammonium ion and the like. Triethylalkylammonium ion; triethylalkylammonium ion such as triethyldodecylammonium ion, triethyltetradecylammonium ion, triethylhexadecylammonium ion, triethyloctadecylammonium ion; tributyldodecylammonium ion, tributyltetradecylammonium ion, tributylhexadecylammonium ion , Tributylalkylammonium ion, such as tributyloctadecylammonium ion; dimethyldioctylammonium ion, dimethyldidecylammonium ion, dimethylditetradecylammonium ion, dimethyldihexadecylammonium ion, dimethyldioctadecylammonium ion (dimethyldisstearylammonium ion) Didimethyldialkylammonium ion, such as dimethyldidodecylammonium ion; diethyldialkylammonium ion, diethylditetradecylammonium ion, diethyldihexadecylammonium ion, diethyldioctadecylammonium ion, etc .; Dibutyldialkylammonium ions such as ions, dibutyldidecylammonium ion, dibutyldidodecylammonium ion, dibutylditetradecylammonium ion, dibutyldihexadecylammonium ion, dibutyldioctadecylammonium ion; trioctylmethylammonium ion, tridodecylmethyl Trialkylmethylammonium ions such as ammonium ion and tritetradecylmethylammonium ion; trialkylethylammonium ion such as trioctylethylammonium ion and tridodecylethylammonium ion; trioctylbutylammonium ion, tridecylbutylammonium ion and the like. , Trialkylbutylammonium ion; etc. Organic ammonium On is mentioned.

The component (B) can be produced by ion-exchange a layered silicate mineral with organic onium ions. At the time of ion exchange, the organic onium ion may be a salt of the organic onium ion and an anion (organic onium salt). Examples of the anion include Cl ⁻ , Br ⁻ , NO ₃ ⁻ , OH ⁻ , CH ₃ COO ⁻ , CH ₃ SO ₃ ^{− and the} like. In addition, one type of these anions may be used alone, or two or more types may be used in any combination.

Specific examples of the method for producing the component (B) include a method of mixing an aqueous dispersion of a layered silicate mineral and an aqueous solution of an organic onium salt at an appropriate temperature (for example, 60 ° C to 70 ° C). .. Further, as another specific example, there is a method of appropriately kneading a layered silicate mineral and an organic onium salt.

As the component (B), a commercially available product can be used. Commercially available products include, for example, "Smekton STN" manufactured by Kunimine Kogyo Co., Ltd., "Smekton SAN" (organized hectorite), "Orben M" manufactured by Shiraishi Kogyo Co., Ltd. (organized montmorillonite), and "Esben" manufactured by Hojun. Examples include "NX" (organized montmorillonite) and "Benton series" (organized montmorillonite) manufactured by Toshin Kasei Co., Ltd.

(B) The organicized layered silicate mineral may be used alone or in combination of two or more.

(B) The average particle size of the organicized layered silicate mineral is preferably 1 nm to 100 μm, more preferably 5 nm to 50 μm, and further preferably 10 nm to 10 μm. This average particle size can be measured by the same method as for the component (A).

(B) The content of the organicized layered silicate mineral is preferably 0. When the non-volatile component in the magnetic paste is 100% by mass from the viewpoint of obtaining a cured product in which the resin seepage property is suppressed. It is 1% by mass or more, more preferably 0.3% by mass or more, still more preferably 0.5% by mass or more. The upper limit is preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass, from the viewpoint of improving the maintenance of magnetic properties and lowering the paste viscosity to improve printability. It is as follows.

<(C) Binder resin>
The magnetic paste contains (C) a binder resin. Examples of the binder resin include epoxy resin, phenol resin, naphthol resin, benzoxazine resin, active ester resin, cyanate ester resin, carbodiimide resin, amine resin, acid anhydride resin and the like. Thermocurable resins; examples thereof include thermoplastic resins such as phenoxy resin, acrylic resin, polyvinyl acetal resin, butyral resin, polyimide resin, polyamideimide resin, polyether sulfone resin, and polysulfone resin. As the binder resin (C), it is preferable to use a thermosetting resin used when forming an insulating layer of a wiring board, and an epoxy resin is particularly preferable. (C) The binder resin may be used alone or in combination of two or more. Hereinafter, each resin will be described. Here, it reacts with an epoxy resin such as a phenol-based resin, a naphthol-based resin, a benzoxazine-based resin, an active ester-based resin, a cyanate ester-based resin, a carbodiimide-based resin, an amine-based resin, and an acid anhydride-based resin. The components that can cure the magnetic paste are collectively called "curing agent".

-Thermosetting resin-
The epoxy resin as the thermosetting resin is, for example, glycyrrole type epoxy resin; 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; naphthol novolac type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, etc. Amin-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; Containing epoxy resin; cyclohexanedimethanol type epoxy resin; trimethylol type epoxy resin; tetraphenylethane type epoxy resin and the like can be mentioned. The epoxy resin may be used alone or in combination of two or more. The epoxy resin is preferably one or more selected from bisphenol A type epoxy resin and bisphenol F type epoxy resin.

The epoxy resin preferably contains an epoxy resin having two or more epoxy groups in one molecule. Further, the epoxy resin preferably has an aromatic structure, and when two or more kinds of epoxy resins are used, it is more preferable that at least one of them has an aromatic structure. The 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 in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass with respect to 100% by mass of the non-volatile component of the epoxy resin. % Or more.

The epoxy resin may be a liquid epoxy resin at a temperature of 25 ° C. (hereinafter, may be referred to as “liquid epoxy resin”) or a solid epoxy resin at a temperature of 25 ° C. (hereinafter, “solid epoxy resin”). ). When the epoxy resin is contained as the component (C), the epoxy resin may contain only the liquid epoxy resin or only the solid epoxy resin, and the liquid epoxy resin and the solid epoxy resin may be combined in combination. Although it may be contained, it is preferable to contain only a liquid epoxy resin from the viewpoint of reducing the viscosity of the magnetic paste.

Liquid epoxy resins include glycyrrole 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, and phenol novolac type epoxy. A resin, an alicyclic epoxy resin having an ester skeleton, a cyclohexanedimethanol type epoxy resin, and an epoxy resin having a butadiene structure are preferable, and a glycylol type epoxy resin, a bisphenol A type epoxy resin, and a bisphenol F type epoxy resin are more preferable. Specific examples of the liquid epoxy resin include "HP4032", "HP4032D" and "HP4032SS" (naphthalene type epoxy resin) manufactured by DIC; "828US" and "jER828EL" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd. , "JER807" (bisphenol F type epoxy resin), "jER152" (phenol novolak type epoxy resin); "630", "630LSD" manufactured by Mitsubishi Chemical Co., Ltd., "ED-523T" (glycirole type epoxy resin) manufactured by ADEKA. (Adecaglycylol)), "EP-3980S" (glycidylamine type epoxy resin), "EP-4088S" (dicyclopentadiene type epoxy resin); "ZX1059" (bisphenol A type epoxy resin) manufactured by Nippon Steel & Sumitomo Metal Corporation (Mixed product of bisphenol F type epoxy resin); "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX Co., Ltd .; "Selokiside 2021P" (alicyclic epoxy resin having an ester skeleton) manufactured by Daicel Co., Ltd., " PB-3600 ”(epoxy resin having a butadiene structure);“ ZX1658 ”,“ ZX1658GS ”(liquid 1,4-glycidylcyclohexane) manufactured by Nippon Steel Chemical Co., Ltd. and the like can be mentioned. These may be used alone or in combination of two or more.

Examples of the solid epoxy resin include 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 the solid epoxy resin include "HP4032H" (naphthalene type epoxy resin), "HP-4700", "HP-4710" (naphthalen type tetrafunctional epoxy resin), and "N-690" manufactured by DIC. Cresol novolak type epoxy resin), "N-695" (cresol novolak 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" manufactured by Nippon Kayaku Co., Ltd. ( Trisphenol type epoxy resin), "NC7000L" (naphthol novolac type epoxy resin), "NC3000H", "NC3000", "NC3000L", "NC3100" (biphenyl type epoxy resin); "ESN475V" manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd. ( Naphthalene type epoxy resin), "ESN485" (naphthol novolac type epoxy resin); "YX4000H", "YL6121" (biphenyl type epoxy resin), "YX4000HK" (bixilenol type epoxy resin), "YX8800" manufactured by Mitsubishi Chemical Co., Ltd. (Anthracene type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemical Co., Ltd., "YL7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd., "YL7800" (fluorene type epoxy resin) , "JER1010" (solid bisphenol A type epoxy resin), "jER1031S" (tetraphenylethane type epoxy resin) and the like. These may be used alone or in combination of two or more.

When a liquid epoxy resin and a solid epoxy resin are used in combination as the component (C), the amount ratio (liquid epoxy resin: solid epoxy resin) thereof is a mass ratio, preferably 1: 0.1 to 1: 1. 4, more preferably 1: 0.3 to 1: 3.5, still more preferably 1: 0.6 to 1: 3. When the quantitative ratio of the liquid epoxy resin and the solid epoxy resin is in such a range, the desired effect of the present invention can be remarkably obtained.

The epoxy equivalent of the epoxy resin as the component (C) is preferably 50 to 5000, more preferably 50 to 3000, still more preferably 80 to 2000, and even more preferably 110 to 1000. Within this range, the crosslink density of the cured product becomes sufficient, and a magnetic layer having a small surface roughness can be obtained. The epoxy equivalent can be measured according to JIS K7236, and is the mass of the resin containing 1 equivalent of the epoxy group.

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

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

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

Examples of the phenol compound or naphthol compound include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthalin, 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, dihydroxybenzophenol, trihydroxybenzophenone, tetrahydroxybenzophenone, fluoroglucin, Examples thereof include benzenetriol, dicyclopentadiene-type diphenol compound, and phenol novolac. Here, the "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing two phenol molecules with one dicyclopentadiene molecule.

Preferred specific examples of the active ester-based resin include an active ester-based resin containing a dicyclopentadiene-type diphenol structure, an active ester-based resin containing a naphthalene structure, an active ester-based resin containing an acetylated product of phenol novolac, and a benzoyl of phenol novolac. Examples thereof include active ester-based resins containing compounds. Of these, an active ester resin containing a naphthalene structure and an active ester resin containing a dicyclopentadiene type diphenol structure are more preferable. The "dicyclopentadiene-type diphenol structure" represents a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

Commercially available products of the active ester resin include "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", and "HPC-8000H-" as active ester resins containing a dicyclopentadiene type diphenol structure. "65TM", "EXB-8000L-65TM" (manufactured by DIC); "EXB9416-70BK", "EXB-8150-65T" (manufactured by DIC) as an active ester resin containing a naphthalene structure; "DC808" (manufactured by Mitsubishi Chemical Co., Ltd.) as an active ester-based resin containing; "YLH1026" (manufactured by Mitsubishi Chemical Co., Ltd.) as an active ester-based resin containing a benzoylated product of phenol novolac; "DC808" (manufactured by Mitsubishi Chemical Co., Ltd.); "YLH1026" (manufactured by Mitsubishi Chemical Co., Ltd.), "YLH1030" (manufactured by Mitsubishi Chemical Co., Ltd.), "YLH1048" (manufactured by Mitsubishi Chemical Co., Ltd.) as active ester-based resins that are benzoylates of phenol novolac. ); Etc. can be mentioned.

As the phenol-based resin and the naphthol-based resin, those having a novolak structure are preferable from the viewpoint of heat resistance and water resistance. Further, from the viewpoint of adhesion to the conductor layer, a nitrogen-containing phenol-based curing agent is preferable, and a triazine skeleton-containing phenol-based resin is more preferable.

Specific examples of the phenolic resin and the naphthol resin include, for example, "MEH-7700", "MEH-7810", "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., "NHN" and "CBN" manufactured by Nippon Kayaku Co., Ltd. , "GPH", "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN-495V" "SN375", "SN395", DIC manufactured by Nippon Steel & Sumitomo Metal Corporation Examples thereof include "TD-2090", "LA-7052", "LA-7054", "LA-1356", "LA-3018-50P", and "EXB-9500" manufactured by the same company.

Specific examples of the benzoxazine-based resin include "JBZ-OD100" (benzoxazine ring equivalent 218), "JBZ-OP100D" (benzoxazine ring equivalent 218), and "ODA-BOZ" (benzoxazine ring) manufactured by JFE Chemical. Equivalent 218); "P-d" (benzoxazine ring equivalent 217), "FA" (benzoxazine ring equivalent 217) manufactured by Shikoku Kasei Kogyo Co., Ltd .; "HFB2006M" (benzoxazine ring equivalent) manufactured by Showa Polymer Co., Ltd. 432) and the like.

Examples of the cyanate ester resin include bisphenol A dicyanate, polyphenol cyanate, oligo (3-methylene-1,5-phenylencyanate), 4,4'-methylenebis (2,6-dimethylphenylcyanate), and 4,4'. -Etilidendiphenyl disyanate, hexafluorobisphenol A dicyanate, 2,2-bis (4-cyanate) phenylpropane, 1,1-bis (4-cyanatephenylmethane), bis (4-cyanate-3,5-dimethylphenyl) ) Bifunctional cyanate resins such as methane, 1,3-bis (4-cyanatephenyl-1- (methylethylidene)) benzene, bis (4-cyanatephenyl) thioether, and bis (4-cyanatephenyl) ether; phenol. Examples thereof include polyfunctional cyanate resins derived from novolak, cresol novolak, and the like; prepolymers in which these cyanate resins are partially triazined. Specific examples of the cyanate ester resin include "PT30" and "PT60" (phenol novolac type polyfunctional cyanate ester resin), "ULL-950S" (polyfunctional cyanate ester resin), and "BA230" manufactured by Lonza Japan. Examples thereof include "BA230S75" (a prepolymer in which a part or all of bisphenol A dicyanate is triazined to form a trimer).

Specific examples of the carbodiimide-based resin include carbodilite (registered trademark) V-03 (carbodiimide group equivalent: 216, V-05 (carbodiimide group equivalent: 262), V-07 (carbodiimide group equivalent: 200)) manufactured by Nisshinbo Chemical Co., Ltd. V-09 (carbodiimide group equivalent: 200); Stavaxol® P (carbodiimide group equivalent: 302) manufactured by Rheinchemy.

Examples of the amine-based resin include resins having one or more amino groups in one molecule, and examples thereof include aliphatic amines, polyether amines, alicyclic amines, and aromatic amines. Of these, aromatic amines are preferable from the viewpoint of achieving the desired effects of the present invention. As the amine-based resin, a primary amine or a secondary amine is preferable, and a primary amine is more preferable. Specific examples of the amine-based curing agent include 4,4'-methylenebis (2,6-dimethylaniline), diphenyldiaminosulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'. -Diaminodiphenyl sulfone, m-phenylenediamine, m-xylylene diamine, diethyltoludiamine, 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-diphenylmethane Diamine, 2,2-bis (4-aminophenyl) propane, 2,2-bis (4- (4-aminophenoxy) 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, Examples thereof include bis (4- (3-aminophenoxy) phenyl) sulfone. Commercially available products may be used as the amine resin, for example, "KAYABOND C-200S", "KAYABOND C-100", "Kayahard A-A", "Kayahard AB", and "Kayahard" manufactured by Nippon Kayaku Corporation. Examples include "AS" and "Epicure W" manufactured by Mitsubishi Chemical Corporation.

Examples of the acid anhydride-based resin include resins having one or more acid anhydride groups in one molecule. Specific examples of the acid anhydride-based resin include phthalic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrohydride phthalic acid, methylnadic acid anhydride, and hydride methylnadic acid anhydride. Trialkyltetrahydrohydride phthalic acid, dodecenyl anhydride succinic acid, 5- (2,5-dioxotetrahydro-3-franyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, trimellith anhydrous Acid, pyromellitic anhydride, benzophenone tetracarboxylic acid dianhydride, biphenyltetracarboxylic acid dianhydride, naphthalenetetracarboxylic acid dianhydride, oxydiphthalic acid dianhydride, 3,3'-4,4'-diphenyl Sulphontetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro-2,5-dioxo-3-franyl) -naphtho [1,2-C] furan-1, Examples thereof include 3-dione, ethylene glycol bis (anhydrotrimethylate), and polymer-type acid anhydrides such as styrene / maleic acid resin in which styrene and maleic acid are copolymerized.

When the epoxy resin and the curing agent are contained as the component (C), the amount ratio of the epoxy resin to all the curing agents is [total number of epoxy groups of the epoxy resin]: [total number of reactive groups of the curing agent]. The ratio is preferably in the range of 1: 0.01 to 1: 5, more preferably 1: 0.5 to 1: 3, and even more preferably 1: 1 to 1: 2. Here, the "number of epoxy groups of the epoxy resin" is a value obtained by adding all the values obtained by dividing the mass of the non-volatile component of the epoxy resin present in the first resin composition by the epoxy equivalent. The "number of active groups of the curing agent" is a total 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 polystyrene-equivalent weight average molecular weight of the thermoplastic resin is preferably 30,000 or more, more preferably 50,000 or more, and further preferably 100,000 or more. Further, it is preferably 1 million or less, more preferably 750,000 or less, and further preferably 500,000 or less. The polystyrene-equivalent weight average molecular weight of the thermoplastic resin is measured by a gel permeation chromatography (GPC) method. Specifically, the polystyrene-equivalent weight average molecular weight of the thermoplastic resin is "LC-9A / RID-6A" manufactured by Shimadzu Corporation as a measuring device and "Shodex K-800P / K-804L" manufactured by Showa Denko Corporation as a column. / K-804L ”can be calculated by measuring the column temperature at 40 ° C. using chloroform or the like as a mobile phase 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, naphthalene skeleton, anthracene skeleton, adamantan skeleton, and terpene. Examples thereof include phenoxy resins having one or more skeletons selected from the group consisting of skeletons and trimethylcyclohexane skeletons. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. The phenoxy resin may be used alone or in combination of two or more. Specific examples of the phenoxy resin include "1256" and "4250" (both bisphenol A skeleton-containing phenoxy resin), "YX8100" (bisphenol S skeleton-containing phenoxy resin), and "YX6954" (bisphenol acetophenone) manufactured by Mitsubishi Chemical Corporation. (Skeletal-containing phenoxy resin), and also "FX280" and "FX293" manufactured by Nippon Steel & Sumitomo Metal Corporation, "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30", "YL7769BH30" manufactured by Mitsubishi Chemical Corporation. , "YL6794", "YL7213", "YL7290", "YL7482" and the like.

As the acrylic resin, a functional group-containing acrylic resin is preferable, and an epoxy group-containing acrylic resin having a glass transition temperature of 25 ° C. or lower is more preferable, from the viewpoint of further lowering the coefficient of thermal expansion and elastic modulus.

The number average molecular weight (Mn) of the functional group-containing acrylic resin is preferably 1,000,000 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 1000 to 50,000, and more preferably 2,500 to 30,000.

As the epoxy group-containing acrylic resin having a glass transition temperature of 25 ° C. or lower, an epoxy group-containing acrylic acid ester copolymer resin having a glass transition temperature of 25 ° C. or lower is preferable, and a specific example thereof is “SG” manufactured by Nagase ChemteX Corporation. -80H ”(epoxy group-containing acrylic acid ester copolymer resin (number average molecular weight Mn: 350,000 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 (number average molecular weight Mn: 850000 g / mol, epoxy value 0.21 eq / kg, glass transition temperature 12 ° C.)).

Specific examples of polyvinyl acetal resin and butyral resin include electrified butyral "4000-2", "5000-A", "6000-C", "6000-EP" manufactured by Denki Kagaku Kogyo Co., Ltd., and Sekisui Kagaku Kogyo Co., Ltd. Examples thereof include Eslek BH series, BX series, KS series such as "KS-1", BL series such as "BL-1", and BM series.

Specific examples of the polyimide resin include "Ricacoat SN20" and "Ricacoat PN20" manufactured by NEW JAPAN CHEMICAL CO., LTD. Specific examples of the polyimide resin include a linear polyimide obtained by reacting a bifunctional hydroxyl group-terminated polybutadiene, a diisocyanate compound and a tetrabasic acid anhydride (polyimide described in JP-A-2006-37083), and a polysiloxane skeleton. Examples thereof include modified polyimides such as contained polyimides (polyimides described in JP-A-2002-12667 and JP-A-2000-31386).

Specific examples of the polyamide-imide resin include "Vilomax HR11NN" and "Vilomax HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of the polyamide-imide resin include modified polyamide-imides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamide-imide) manufactured by Hitachi Chemical Industries, Ltd.

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

Specific examples of the polysulfone resin include polysulfones "P1700" and "P3500" manufactured by Solvay Advanced Polymers.

Among them, the thermoplastic resin is preferably one or more selected from phenoxy resin, polyvinyl acetal resin, butyral resin, and acrylic resin having a weight average molecular weight of 30,000 or more and 1 million or less.

The content of the binder resin (C) is preferably 1% by mass or more, more preferably 1% by mass or more, 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. Is 3% by mass 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 exhibited, but is preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less.

By containing (B) an organicized layered silicate mineral, the magnetic paste of the present invention (C) suppresses the resin exudation property of the binder resin. The content of the component (B) when the non-volatile component in the magnetic paste was 100% by mass was defined as B1, and the content of the component (C) when the non-volatile component in the magnetic paste was 100% by mass was defined as C1. In this case, C1 / B1 is preferably 1 or more, more preferably 3 or more, still more preferably 5 or more, from the viewpoint of shape maintenance and handleability after printing. The upper limit is preferably 30 or less, more preferably 25 or less, still 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 an amine-based curing accelerator, an imidazole-based curing accelerator, a phosphorus-based curing accelerator, a guanidine-based curing accelerator, a metal-based curing accelerator, and the like. As the curing accelerator, an amine-based curing accelerator and an imidazole-based curing accelerator are preferable from the viewpoint of reducing the viscosity of the magnetic paste. The curing accelerator may be used alone or in combination of two or more.

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

As the amine-based curing accelerator, a commercially available product may be used, and examples thereof include "PN-50", "PN-23", and "MY-25" manufactured by Ajinomoto Fine-Techno.

Examples of the imidazole-based curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, and the like. 2-Ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 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-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2- Phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazolin , 2-Imidazole compounds such as phenylimidazolin and adducts of imidazole compounds and epoxy resins are mentioned, with 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole being preferred.

As the imidazole-based curing accelerator, a commercially available product may be used, and examples thereof include "2PHZ-PW" manufactured by Shikoku Chemicals Corporation and "P200-H50" manufactured by Mitsubishi Chemical Corporation.

Examples of the phosphorus-based curing accelerator include triphenylphosphine, phosphonium borate compound, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, and (4-methylphenyl) triphenylphosphonium thiocyanate. , Tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate and the like, and triphenylphosphine and tetrabutylphosphonium decanoate are preferable.

Examples of the guanidine-based curing accelerator include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1- (o-tolyl) guanidine, dimethylguanidine, diphenylguanidine, and 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-octadecylviguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1 Examples thereof include allylbiguanide, 1-phenylbiguanide, 1- (o-tolyl) biguanide, and dicyandiamide, 1,5,7-triazabicyclo [4.4.0] deca-5-ene is preferable.

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

(D) The curing accelerator is at least one selected from an acid anhydride-based epoxy resin curing agent, an amine-based curing accelerator, and an imidazole-based curing accelerator from the viewpoint of obtaining the desired effect of the present invention. Is preferable, and at least one selected from an amine-based curing accelerator and an imidazole-based curing accelerator is more preferable.

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

<(E) Dispersant>
The magnetic paste may further contain (E) a dispersant as an arbitrary component.

(E) Dispersants include, for example, phosphate ester dispersants such as polyoxyethylene alkyl ether phosphoric acid; anionic salts such as sodium dodecylbenzel sulfonate, sodium laurylate, and ammonium salts of polyoxyethylene alkyl ether sulfate. Dispersants; Organosiloxane-based dispersants, acetylene glycols, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl amines, polyoxyethylene alkyl amides, etc. Examples thereof include nonionic dispersants. Of these, anionic dispersants are preferred. The dispersant may be used alone or in combination of two or more.

As the phosphoric acid ester-based dispersant, a commercially available product can be used. Examples of commercially available products include "RS-410", "RS-610", "RS-710" and the like of the "Phosphanol" series manufactured by Toho Chemical Industry Co., Ltd.

Examples of the organosiloxane-based dispersant include "BYK347" and "BYK348" manufactured by Big Chemie.

As commercially available polyoxyalkylene-based dispersants, NOF Corporation's "Marialim" series "AKM-0531", "AFB-1521", "SC-0505K", "SC-1015F" and "SC-0708A" , And "HKM-50A" and the like.

As acetylene glycol, as a commercially available product, Air Products and Chemicals Inc. Examples thereof include "82", "104", "440", "465" and "485", and "olefin Y" of the "Surfinol" series manufactured by EM.

The content of the dispersant (E) is preferably 0.1% by mass or more, more preferably 0% by mass, when the non-volatile component in the magnetic paste is 100% by mass, from the viewpoint of remarkably exerting the effect of the present invention. It is 3% by mass or more, more preferably 0.5% by mass or more, and the upper limit is preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less.

<(F) Other additives>
If necessary, the magnetic paste may further contain (F) other additives, and such other additives include, for example, a curing retarder such as triethyl borate for improving pot life. Organic metal compounds such as inorganic fillers (excluding those corresponding to magnetic powders or organic layered silicate minerals), flame retardants, organic fillers, organic copper compounds, organic zinc compounds and organic cobalt compounds. , And resin additives such as thickeners, defoaming agents, leveling agents, adhesion-imparting agents, and colorants.

The content of the solvent contained in the above-mentioned magnetic paste is preferably less than 1.0% by mass, more preferably 0.8% by mass or less, still more preferably 0.5% by mass, based on the total mass of the magnetic paste. Hereinafter, it is particularly preferably 0.1% by mass or less. The lower limit is 0.001% by mass or more, or no content, although there is no particular limitation. The viscosity of the magnetic paste can be lowered even if it does not contain a solvent. Since the amount of the solvent in the magnetic paste is small, it is possible to suppress the generation of voids due to the volatilization of the solvent, and it is also possible to adapt to vacuum printing.

<Manufacturing method of magnetic paste>
The magnetic paste can be produced, for example, by a method of stirring the compounding components using a stirring device such as a three-roll or rotary mixer.

<Physical characteristics of magnetic paste, etc.>
FIG. 2 is a cross-sectional view schematically showing an example of a cross section of the magnetic layer 120 formed on the substrate 110. As shown in FIG. 2, when a magnetic paste (not shown) is printed on the substrate 110 and cured to form the magnetic layer 120, a part of the resin exudes from the edge 120E of the magnetic layer 120 and stains. The protrusion 130 may be formed. When the above-mentioned magnetic paste is used, the exudation of the resin can be suppressed. Therefore, the flow distance L of the exuded resin can be shortened. For example, a cured product obtained by heat-curing a magnetic paste (for example, a cured product heat-cured at 150 ° C. for 60 minutes) exhibits a characteristic that the resin seepage property after screen printing is suppressed. Specifically, the magnetic paste is screen-printed on a printed circuit board and heat-cured at 150 ° C. for 60 minutes after printing to obtain an evaluation board. The maximum distance of the flow distance of the resin exuded from the end of the printed pattern of this evaluation board is preferably 500 μm or less, more preferably 480 μm or less, and further preferably 450 μm or less. 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-mentioned magnetic paste can be used as a magnetic paste for forming an inductor element.

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

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

A cured product obtained by thermally curing a magnetic paste (for example, a cured product heat-cured at 180 ° C. for 90 minutes) exhibits a characteristic of low magnetic loss at a normal frequency of 100 MHz. For example, the 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, still more preferably 0.3 or less. Further, the lower limit can usually be 0.001 or more.

[Inductor element]
The inductor element of the present invention includes a magnetic layer which is a cured product of the magnetic paste of the present invention. Here, the inductor element includes not only the inductor element as an electronic component but also the inductor element included in the circuit board. FIG. 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 spiral shape around the core portion 14. Has been done. Further, a magnetic layer 12 is embedded in the core portion 14.

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 the magnetic paste, the resin exudability of the magnetic layer 12 is suppressed. Therefore, the wiring 13 can be formed with a short distance between the wirings. Hereinafter, the inductor element and the manufacturing method thereof will be described through the manufacturing method of the inductor element.

The manufacturing method of the inductor element is
(1) A step of printing a magnetic paste on a substrate and thermosetting the magnetic paste to form a first magnetic layer.
(2) Step of forming wiring on the first magnetic layer,
(3) A step of printing a magnetic paste on a first magnetic layer, a core portion and wiring, and heat-curing the magnetic paste to form a second magnetic layer.
including. Here, the magnetic layer 12 includes the first and second magnetic layers.

<Process (1)>
In the step (1), the magnetic paste is printed on the substrate and the magnetic paste is thermally cured to form the first magnetic layer. In carrying out the step (1), a step of preparing a magnetic paste may be included. The magnetic paste is as described above.

The substrate is usually an insulating substrate. Examples of the substrate material include an insulating substrate such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, and a thermosetting polyphenylene ether substrate. The substrate may be an inner layer circuit board in which wiring or the like is built within the thickness thereof.

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

The magnetic paste is applied onto the substrate by full-page printing by printing or pattern printing. As the printing method, screen printing is usually performed, but other printing methods may be adopted. After coating, it is thermoset to obtain a first magnetic layer.

The thermosetting conditions of the magnetic paste differ 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, still more preferably 150 ° C. or higher, preferably 240 ° C. or lower, and It is more preferably 220 ° C. or lower, still more preferably 200 ° C. or lower. The curing time of the magnetic paste is preferably 5 minutes or more, more preferably 10 minutes or more, further preferably 15 minutes or more, preferably 120 minutes or less, more preferably 100 minutes or less, still more preferably 90 minutes or less. ..

Before the magnetic paste is thermally cured, the magnetic paste may be subjected to a preheating treatment in which the magnetic paste is heated at a temperature lower than the curing temperature. The temperature of the preheat treatment is preferably 50 ° C. or higher, preferably 60 ° C. or higher, more preferably 70 ° C. or higher, preferably less than 120 ° C., preferably 110 ° C. or lower, and more preferably 100 ° C. or higher. The time of the preheat 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 the step (2), the wiring is formed on the first magnetic layer formed in the step (1). Examples of the wiring forming method include a plating method, a sputtering method, a vapor deposition method, and the like, and the plating method is particularly 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 spiral wiring pattern.

Wiring materials include, for example, single metals such as gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, indium; gold, platinum, palladium, silver, Included are alloys of two or more metals selected from the group copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium. Above all, from the viewpoint of versatility, cost, ease of patterning, etc., it is possible to use chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel-chromium alloy, copper nickel alloy, copper titanium alloy. It is preferable to use chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or a nickel-chromium alloy, and even more preferably 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, an unnecessary plating seed layer is removed by a treatment such as etching to form a wiring having a desired wiring pattern. can. After forming the wiring, annealing treatment may be performed if necessary for the purpose of improving the peel strength of the wiring. The 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 is formed on the formed plating seed layer to expose a part of the plating seed layer corresponding to the spiral pattern. In this case, after forming an electrolytic plating layer by electrolytic plating on the exposed plating seed layer, the mask pattern is removed. Then, the unnecessary plating seed layer is removed by a treatment such as etching to form a wiring having a desired pattern.

The thickness of the wiring is preferably 70 μm or less, more preferably 60 μm or less, still more preferably 50 μm or less, still more preferably 40 μm or less, particularly preferably 30 μm or less, 20 μm or less, 15 μm from the viewpoint of thinning. It is less than or equal to 10 μm or less. The lower limit is preferably 1 μm or more, more preferably 3 μm or more, still more preferably 5 μm or more.

<Process (3)>
In the step (3), the magnetic paste is printed on the first magnetic layer, the core portion and the wiring, and the magnetic paste is thermally cured to form the second magnetic layer. The method for forming the second magnetic layer is the same as that for the first magnetic layer. The magnetic paste forming the first magnetic layer and the magnetic paste forming the second magnetic layer may be the same or different from each other.

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

[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 an electronic component such as a semiconductor chip, and can also be used as a (multilayer) printed wiring board using such a wiring board as an inner layer board. Further, the wiring board can be used as an individualized chip inductor component, or the chip inductor component can be used as a surface-mounted printed wiring board.

Further, various aspects of the semiconductor device can be manufactured by using such a wiring board. The semiconductor device including such a wiring board can be suitably used for electric products (for example, computers, mobile phones, digital cameras, televisions, etc.) and vehicles (for example, motorcycles, automobiles, trains, ships, aircraft, etc.) and the like. ..

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. In the following description, "parts" and "%" representing quantities mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

<Example 1>
Epoxy resin ("ZX-1059", a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin, manufactured by Nippon Steel & Sumitomo Metal Corporation) 10 parts by mass, epoxy resin ("ED-523T", low viscosity epoxy resin, ADEKA) 5 parts, dispersant ("RS-710", polymer anionic dispersant, manufactured by Toho Kagaku Co., Ltd.), 1 part by mass, curing accelerator ("2P4MZ", imidazole-based curing accelerator, manufactured by Shikoku Kasei Co., Ltd.) 1 By mass, magnetic powder ("M05S", Fe-Mn-based ferrite, average particle size 3 μm, manufactured by Powder Tech) 100 parts by mass, organic smectite ("Smecton STN", trioctylmethylammonium-treated epoxyite, Kunimine Kogyo 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 (“Smecton STN”, trioctylmethylammonium-treated hectorite, manufactured by Kunimine Industries, 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 items.

<Example 3>
In Example 1, the amount of organic smectite (“Smecton STN”, trioctylmethylammonium-treated hectorite, manufactured by Kunimine Industries, 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 items.

<Example 4>
In Example 1, 100 parts by mass of a magnetic powder (“M05S”, Fe-Mn-based ferrite, average particle size 3 μm, manufactured by Powder Tech Co., Ltd.) was used as a magnetic powder (“AW2-08PF3F”, Fe-Cr-Si based). Alloy (amorphous), average particle size 3.0 μm, manufactured by Epson Atmix Co., Ltd.) was changed to 100 parts by mass. A magnetic paste was prepared in the same manner as in Example 1 except for the above items.

<Example 5>
In Example 1, 2 parts by mass of organic smectite (“Smecton STN”, trioctylmethylammonium-treated hectorite, manufactured by Kunimine Industries, Ltd.) was added to organic smectite (“Smecton SAN”, dimethyl distearylammonium-treated hectorite, Kunimine). (Made by Kogyo Co., Ltd.) Changed to 2 parts by mass. A magnetic paste was prepared in the same manner as in Example 1 except for the above items.

<Example 6>
In Example 1, 2 parts by mass of organic smectite (“Smecton STN”, trioctylmethylammonium-treated hectorite, manufactured by Kunimine Kogyo Co., Ltd.) was added to organic montmorillonite (“Orben M”, dimethyldioctadecylammonium-treated montmorillonite, Shiraishi Kogyo). (Manufactured by the company) Changed to 2 parts by mass. A magnetic paste was prepared in the same manner as in Example 1 except for the above items.

<Comparative Example 1>
In Example 1, 2 parts by mass of organic smectite (“Smecton 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 items.

<Comparative Example 2>
In Example 1, 2 parts by mass of organic smectite (“Smecton STN”, trioctylmethylammonium-treated hectorite, manufactured by Kunimine Kogyo Co., Ltd.) was added to non-organized smectite (“Smecton SWN”, hectorite, Kunimine Kogyo Co., Ltd.). Made) Changed to 1 part by mass. A magnetic paste was prepared in the same manner as in Example 1 except for the above items.

<Comparative Example 3>
In Example 1, 2 parts by mass of organic smectite (“Smecton STN”, trioctylmethylammonium-treated hectorite, manufactured by Kunimine Kogyo Co., Ltd.) was added to 1 part by mass of hydrophobic fumed silica (AEROSIL RY200, manufactured by Aerosil Japan Co., Ltd.). changed. A magnetic paste was prepared in the same manner as in Example 1 except for the above items.

<Measurement of magnetic paste viscosity>
Keep the temperature of the magnetic paste of each example and each comparative example at 25 ± 2 ° C, and use an E-type viscometer (“RE-80U” manufactured by Toki Sangyo Co., Ltd., 3 ° × R9.7 cone, rotation speed 5 rpm). The viscosity was measured using. In addition, the measured viscosity was evaluated according to the following criteria from the viewpoint of printability and ease of removing air bubbles.
◯: 20 Pa · s or more and less than 200 Pa · s ×: Less than 20 Pa · s or 200 Pa · s or more

<Measurement of resin exudation after screen printing>
(1) Preparation of Printed Evaluation Board As a printed circuit board, both sides of a glass cloth base material epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.8 mm, R5715E manufactured by Matsushita Electric Works Co., Ltd.) are micro-etched. A copper surface roughened by etching by 1 μm with CZ8100) manufactured by Mec Co., Ltd. was prepared. As a printing member, a metal mask (plate material SUS304, opening method laser, no surface treatment, mask thickness 40 μm, opening pattern 1 mm × 3 mm rectangle, manufactured by Process Lab Micron) is prepared, and a metal squeegee (plate material SUS304, squeegee) is prepared. A thickness of 0.25 mm, no surface treatment, manufactured by Taku Giken Co., Ltd.) was prepared.

For printing, the printed circuit board and the printing member are closely fixed, and the metal squeegee is swept at an angle of 45 deg, a speed of 10 mm / sec, and a linear pressure of 6.5 N / cm to sweep the magnetic paste produced in each example and each comparative example. I went there. After printing, the printing member was removed, and the magnetic paste was cured under the curing conditions of 150 ° C. for 60 minutes to prepare a print evaluation substrate.

(2) Evaluation of resin seepage property (resin seepage amount) The edge of the 1 mm × 3 mm rectangular print pattern of the produced print evaluation substrate was photographed using a digital microscope (Keyence, VHX-900). Then, the resin exuded from the print evaluation substrate was observed. Of the flow distance of the resin exuded from the edge of the print pattern, the maximum distance was measured as the resin exudability (resin exudation amount). In addition, the resin exudation property was evaluated according to the following criteria.
◯: Resin seepage amount is less than 500 μm ×: Resin seepage amount is 500 μm or more

<Measurement of relative permeability and magnetic loss>
As a support, a polyethylene terephthalate (PET) film (“PET501010” manufactured by Lintec Corporation, thickness 50 μm) treated with a silicon-based mold release agent was prepared. The magnetic paste produced in each Example and each Comparative Example was uniformly applied on the release surface of the PET film with a doctor blade 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 thermally cure 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 having a width of 5 mm and a length of 18 mm to prepare an evaluation sample. This evaluation sample was prepared using Agilent Technologies (manufactured by Agilent Technologies, "HP8632B") with a measurement frequency of 100 MHz by a 3-turn coil method, and the relative permeability (μ') and magnetic loss (μ') at 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 the organic smectite was significantly improved in resin oozing property. On the other hand, Comparative Example 1 did not contain organic smectite, and a large resin exudation was observed. Further, as can be seen from Comparative Example 2, when the non-organized smectite was used, the resin exudation property was not improved. Further, in Comparative Example 3, hydrophobic fumed silica, which is widely used as a thixotropy-imparting agent, is added, but the resin exudation property is not improved, and the viscosity is increased, so that from the viewpoint of printability and bubble removal. It is out of the preferred range.

1 Inductor element 11 Board 12 Magnetic layer 13 Wiring layer 14 Core part 110 Board 120 Magnetic layer 120E Magnetic layer edge 130 Exud part L Flow distance

Claims (12)

(A) Magnetic powder,
A magnetic paste for screen printing containing (B) an organic layered silicate mineral and (C) a binder resin. The magnetic paste according to claim 1, wherein the component (B) contains an organicized smectite. The magnetic paste according to claim 2, wherein the component (B) contains smectite ion-exchanged with quaternary ammonium ions. The magnetic paste according to any one of claims 1 to 3, wherein the component (B) is at least one selected from organicized hectorite and organicized 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 any one of claims 1 to 5, wherein the component (C) contains a thermosetting resin. The magnetic paste according to any one of claims 1 to 6, wherein the component (C) contains an epoxy resin. The magnetic paste according to any one of claims 1 to 7, wherein the component (A) is at least one selected from iron oxide powder and iron alloy-based metal powder. The content of the component (B) when the non-volatile component in the magnetic paste was 100% by mass was defined as B1, and the content of the component (C) when the non-volatile component in the magnetic paste was 100% by mass was defined as C1. The magnetic paste according to any one of claims 1 to 8, wherein C1 / B1 is 1 or more and 30 or less. The magnetic paste according to any one of claims 1 to 9 , further comprising (E) a dispersant. An inductor element including a magnetic layer which is a cured product of the magnetic paste according to any one of claims 1 to 10. A circuit board comprising the inductor element according to claim 11.

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