Resin particles and circuit board with insulating layer

Abstract

Provided are resin particles capable of exhibiting low thermal expansibility and demonstrating a low dielectric constant.　The resin particles according to the present invention each include a resin particle body and a plurality of silica particles. The plurality of silica particles are present on the surface or inside of the resin particle body. The resin particle body is a polymer of a polymerizable component, and the polymerizable component includes a polymerizable compound having one or more maleimide groups.

Description

Resin particles and circuit board with insulating layer

[0001] The present invention relates to resin particles containing a polymer of a polymerizable compound having one or more maleimide groups, and to a circuit board with an insulating layer using the resin particles.

[0002] Bismaleimide resins are generally known to be resins having low dielectric properties.

[0003] Resin particles using bismaleimide resins are known. Patent Document 1 below discloses polybismaleimide crosslinked particles having a specific repeating structural unit. The polybismaleimide crosslinked particles are obtained by polymerizing a monomer having two maleimide groups, either alone or together with another monomer copolymerizable therewith, by dispersion polymerization.

[0004] Patent Document 1 describes that the particle diameter of the polybismaleimide crosslinked particles can be adjusted to 10 nm to 10 μm, that the polybismaleimide crosslinked particles have excellent monodispersity, and that the polybismaleimide crosslinked particles can be used in resin compositions that require high heat resistance, high insulating properties, and low dielectric properties.

[0005] JP 2012-193325 A

[0006] Resin particles using a bismaleimide resin as described in Patent Document 1 have the problem of poor thermal expansion properties (low dimensional stability).

[0007] It is difficult for conventional resin particles to exhibit both low thermal expansion and low dielectric properties.

[0008] An object of the present invention is to provide resin particles that can exhibit low thermal expansion and low dielectric properties, and a circuit board with an insulating layer that uses the resin particles.

[0009] This specification discloses the following resin particles and circuit board with an insulating layer.

[0010] Item 1. Resin particles comprising a resin particle body and a plurality of silica particles, wherein the plurality of silica particles are present on the surface or inside of the resin particle body, the resin particle body is a polymer of a polymerizable component, and the polymerizable component includes a polymerizable compound having one or more maleimide groups.

[0011] Item 2. The resin particles according to Item 1, wherein the particle diameter of the resin particles is 0.5 μm or more.

[0012] Item 3. The resin particles according to Item 1 or 2, wherein the silica particles have a particle diameter of 1.0 μm or less.

[0013] Item 4. The resin particles according to any one of Items 1 to 3, wherein the ratio of the particle size of the silica particles to the particle size of the resin particles is 0.001 or more and 0.5 or less.

[0014] Item 5. The resin particles according to any one of Items 1 to 4, wherein the content of the silica particles is 0.1% by weight or more and 20% by weight or less, based on 100% by weight of the resin particles.

[0015] Item 6. The resin particles according to any one of Items 1 to 5, wherein the content of the polymerizable compound having one or more maleimide groups is 10% by weight or more based on 100% by weight of the polymerizable component.

[0016] Item 7. The resin particles according to any one of Items 1 to 6, wherein the polymerizable component includes a crosslinkable monomer different from the polymerizable compound having one or more maleimide groups.

[0017] Item 8. The resin particles according to Item 7, wherein the crosslinkable monomer is divinylbenzene or a polymerizable compound having two or more (meth)acryloyl groups.

[0018] Item 9. The resin particles according to Item 7 or 8, wherein the content of the crosslinkable monomer is 10% by weight or more based on 100% by weight of the polymerizable component.

[0019] Item 10. The resin particles according to any one of Items 1 to 9, wherein the resin particles have a thermal expansion coefficient of less than 150 ppm / °C at 50°C to 150°C.

[0020] Item 11. The resin particles according to any one of Items 1 to 10, wherein the resin particles have a dielectric constant of 2.80 F / m or less and a dielectric loss tangent of 0.01 or less.

[0021] Item 12. The resin particle according to any one of Items 1 to 11, wherein, in at least one of the plurality of silica particles, a portion of the silica particle is present inside the resin particle body and a portion of the silica particle is present on the surface of the resin particle body.

[0022] Item 13. A circuit board with an insulating layer, comprising a circuit board and an insulating layer disposed on a surface of the circuit board, the insulating layer containing the resin particles according to any one of items 1 to 12.

[0023] The resin particles according to the present invention comprise a resin particle body and a plurality of silica particles, the plurality of silica particles being present on the surface or inside of the resin particle body, the resin particle body being a polymer of a polymerizable component, the polymerizable component containing a polymerizable compound having one or more maleimide groups. Because the resin particles according to the present invention have the above-mentioned configuration, they can exhibit low thermal expansion and low dielectric properties.

[0024] Fig. 1 is a cross-sectional view schematically showing a resin particle according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view schematically showing a resin particle according to a second embodiment of the present invention. Fig. 3 is a cross-sectional view schematically showing a multilayer printed wiring board using the resin particle according to the first embodiment of the present invention. Fig. 4 is a cross-sectional view illustrating the location of silica particles contained in the resin particle.

[0025] The present invention will be described in detail below. In this specification, for example, "(meth)acryloxy" means one or both of "acryloxy" and "methacryloxy", and "(meth)acrylic" means one or both of "acrylic" and "methacrylic".

[0026] (Resin Particles) The resin particles according to the present invention include a resin particle body and a plurality of silica particles. In the resin particles according to the present invention, the plurality of silica particles are present on the surface or inside of the resin particle body. In the resin particles according to the present invention, the resin particle body is a polymer of a polymerizable component, and the polymerizable component includes a polymerizable compound having one or more maleimide groups.

[0027] The resin particles according to the present invention have the above-described configuration, and therefore can exhibit low thermal expansion and low dielectric properties. The resin particles according to the present invention can achieve both low thermal expansion and low dielectric properties. The resin particles according to the present invention are resistant to thermal expansion even when exposed to high temperatures, and can improve dimensional stability.

[0028] In the resin particles of the present invention, multiple silica particles may be present on the surface (external) of the resin particle body, may be present inside the resin particle body, or may be present on the surface (external) and internally of the resin particle body.

[0029] In the resin particles, any one of the silica particles may be entirely present on the surface (exterior) of the resin particle body, or a portion of any one of the silica particles may be present (exposed) on the surface (exterior) of the resin particle body. In the resin particles, any one of the silica particles may be entirely present inside the resin particle body, or a portion of any one of the silica particles may be present inside the resin particle body. Any one of the silica particles may have a portion present inside the resin particle body (a portion of one silica particle) and a portion present on the surface of the resin particle body (a portion (remaining portion) of one silica particle).

[0030] FIG. 4 is a cross-sectional view illustrating the location of silica particles contained in a resin particle.

[0031] With regard to silica particle X shown in Fig. 4, the entire silica particle X is present on the surface of the resin particle body. With regard to silica particle Y shown in Fig. 4, the entire silica particle Y is present inside the resin particle body. With regard to silica particle Z shown in Fig. 4, a portion of silica particle Z is present inside the resin particle body, and a portion (the remaining portion) of silica particle Z is present on the surface of the resin particle body. The resin particle may contain silica particle X, silica particle Y, or silica particle Z.

[0032] In the resin particles, all of the silica particles may be present on the surface (external) of the resin particle body, or a portion (at least one) of the silica particles may be present on the surface (external) of the resin particle body. In the resin particles, all of the silica particles may be present on the surface (external) of the resin particle body, or at least one of the silica particles may be present on the surface (external) of the resin particle body. In the resin particles, all of the silica particles may be present inside the resin particle body, or a portion (at least one) of the silica particles may be present inside the resin particle body. In the resin particles, all of the silica particles may be present inside the resin particle body, or at least one of the silica particles may be present inside the resin particle body.

[0033] The resin particles may include silica particles present on the surface (external) of the resin particle body, silica particles present on the surface (external) and internal of the resin particle body (a portion of which is external to the resin particle body), and silica particles present internally of the resin particle body. From the viewpoint of further enhancing water repellency, it is preferable that, in at least one of the plurality of silica particles, a portion of the silica particle is present internally of the resin particle body, and a portion of the silica particle is present (exposed) on the surface (external) of the resin particle body. From the viewpoint of further enhancing water repellency, it is preferable that at least one of the plurality of silica particles has a portion present internally of the resin particle body (a portion of one silica particle) and a portion present (exposed) on the surface (external) of the resin particle body (a portion (remaining portion) of one silica particle). From the viewpoint of more effectively exhibiting low thermal expansion, it is preferable that in some (at least one) of the silica particles, a portion of the silica particle is present inside the resin particle body, and a portion of the silica particle is present (exposed) on the surface (exterior) of the resin particle body. From the viewpoint of further enhancing low thermal expansion, it is preferable that some (at least one) of the silica particles have a portion present inside the resin particle body (a portion of one silica particle) and a portion present (exposed) on the surface (exterior) of the resin particle body (a portion (remaining portion) of one silica particle). It is preferable that the resin particles have silica particles present only on the surface (exterior) of the resin particle body, silica particles present on the surface and interior of the resin particle body (a portion present outside the resin particle body), and silica particles present only inside the resin particle body. In these cases, low thermal expansion can be exhibited more effectively.

[0034] The present invention will be specifically described below with reference to the drawings.

[0035] FIG. 1 is a cross-sectional view schematically showing a resin particle according to a first embodiment of the present invention.

[0036] 1 includes a resin particle body 2 and a plurality of silica particles 3. In the resin particle 1, all of the silica particles 3 are present on the surface (external) and internal of the resin particle body 2. In the resin particle 1, a portion of all of the silica particles 3 is present inside the resin particle body 2, and a portion of the silica particles 3 is present on the surface (external) of the resin particle body 2.

[0037] FIG. 2 is a cross-sectional view schematically showing a resin particle according to a second embodiment of the present invention.

[0038] The resin particle 1A shown in FIG. 2 includes a resin particle body 2 and a plurality of silica particles 3A. In the resin particle 1A, at least one of the plurality of silica particles 3A is present inside the resin particle body 2. In the resin particle 1A, a portion (at least one) of the silica particles 3A is present inside the resin particle body 2. In the resin particle 1A, a plurality of silica particles 3A are dispersed in the resin particle body 2. In the resin particle 1A, a plurality of silica particles 3A are present on the surface (external) and internal of the resin particle body 2. In the resin particle 1A, a portion (at least one) of the silica particles 3A is present on the surface (external) and internal of the resin particle body 2. In the resin particle 1A, in at least one of the plurality of silica particles 3A, a portion of the silica particle 3A is present inside the resin particle body 2 and a portion of the silica particle 3A is present on the surface (external) of the resin particle body 2.

[0039] In the resin particle 1A, there are silica particles 3A that are entirely present inside the resin particle body 2 and silica particles 3A that are partially present on the surface (outside) of the resin particle body 2.

[0040] The thermal expansion coefficient of the resin particles at 50°C to 150°C is preferably less than 150 ppm / °C, more preferably 120 ppm / °C or less, even more preferably less than 110 ppm / °C, even more preferably 100 ppm / °C or less, even more preferably 90 ppm / °C or less, particularly preferably 80 ppm / °C or less, even more preferably less than 80 ppm / °C, even more preferably 70 ppm / °C or less, even more preferably 60 ppm / °C or less, and most preferably 50 ppm / °C or less. When the thermal expansion coefficient is below the upper limit (or less than the upper limit), low thermal expansion properties are more effectively exhibited, and dimensional change when the resin particles are exposed to high temperatures can be reduced. Therefore, for example, when the resin particles are used in an insulating layer, etc., even if the insulating layer is exposed to high temperatures, peeling and cracking can be suppressed. The thermal expansion coefficient of the resin particles at 50°C to 150°C may be 0 ppm / °C or more. The range of the thermal expansion coefficient of the resin particles at 50° C. to 150° C. can be set by appropriately selecting the lower limit and the upper limit.

[0041] The thermal expansion coefficient of the resin particles at 50°C to 150°C can be measured, for example, as follows. Using a thermomechanical analyzer (TMA), the resin particles are held at 50°C for 5 minutes, and then heated from 50°C to 160°C at a temperature increase rate of 5°C / min. The linear expansion coefficient from 50°C (at the start of temperature increase) to 150°C (when 150°C is reached) is calculated. For example, a "TMA450" manufactured by TA Instruments is used for the thermomechanical analyzer (TMA).

[0042] The dielectric constant of the resin particles is preferably less than 2.90 F / m, more preferably 2.80 F / m or less, even more preferably 2.70 F / m or less, even more preferably less than 2.70 F / m, particularly preferably 2.60 F / m or less, even more preferably 2.50 F / m or less, and particularly preferably less than 2.50 F / m, and most preferably 2.40 F / m or less. When the dielectric constant of the resin particles is equal to or less than the above upper limit (or less than the above upper limit), low dielectric properties can be more effectively exhibited. The lower limit of the dielectric constant of the resin particles is not particularly limited. The dielectric constant of the resin particles may be 1.80 F / m or more, or may be 1.90 F / m or more. The range of the dielectric constant of the resin particles can be set by appropriately selecting the above lower limit and upper limit.

[0043] The dielectric loss tangent of the resin particles is preferably 0.01 or less, more preferably less than 0.01, even more preferably less than 0.008, even more preferably 0.005 or less, particularly preferably less than 0.005, and most preferably 0.003 or less. When the dielectric loss tangent of the resin particles is equal to or less than the above upper limit (or less than the above upper limit), low dielectric properties can be more effectively exhibited. The lower limit of the dielectric loss tangent of the resin particles is not particularly limited. The dielectric loss tangent of the resin particles may be 0.0001 or more, or may be 0.0005 or more. The range of the dielectric loss tangent of the resin particles can be set by appropriately selecting the above lower limit and upper limit.

[0044] The dielectric constant and dielectric loss tangent of the resin particles can be measured, for example, as follows: A quartz tube is filled with resin particles and placed in a powder measurement resonator. The dielectric constant and dielectric loss tangent of the resin particles at 1 GHz are measured using a dielectric constant measuring device (manufactured by AET).

[0045] The 10% K value of the resin particles at 25°C is preferably 100 N / mm ２ More preferably, 500 N / mm ２ More preferably, 1000 N / mm ２ or more, preferably 20,000 N / mm ２ or less, more preferably 15,000 N / mm ２ or less, more preferably 10,000 N / mm２ Below 8000 N / mm ２ When the 10% K value at 25° C. of the resin particles is equal to or greater than the above lower limit and equal to or less than the above upper limit, interfacial peeling between the silica particles and the resin particle bodies can be suppressed.

[0046] The 10% K value of the resin particles at 25°C can be measured as follows. Using a microcompression tester, the resin particles are compressed with a smooth cylindrical indenter end face (diameter 50 μm, made of diamond) at 25°C under conditions in which a maximum test load of 20 mN is applied for 60 seconds. The load value (N) and compression displacement (mm) at this time are measured. From the obtained measured values, the 10% K value of the resin particles at 25°C can be calculated using the following formula. As the microcompression tester, for example, a "Fisherscope H-100" manufactured by Fischer Instruments Inc. or the like can be used.

[0047] 10% K value (N / mm ２ ) = (3 / 2 １／２ ) F.S. －３／２ ・R －１／２ F: Load value (N) when resin particle is compressed and deformed by 10%; S: Compression displacement (mm) when resin particle is compressed and deformed by 10%; R: Radius of resin particle (mm)

[0048] From the viewpoint of suppressing crushing of the resin particles when molding a composition containing the resin particles, the compression recovery rate of the resin particles at 25°C is preferably 10% or more, more preferably 20% or more, and even more preferably 30% or more, and is preferably 95% or less, more preferably 90% or less, and even more preferably 80% or less. The compression recovery rate of the resin particles at 25°C may be 70% or less.

[0049] The compression recovery rate of the resin particles at 25° C. can be measured as follows.

[0050] Resin particles are scattered on a sample stage. A micro-compression tester is used to apply a load to each scattered resin particle at 25°C toward the center of the resin particle using a smooth cylindrical indenter (diameter 50 μm, made of diamond) with an origin load of 1.0 mN and a reverse load of 10 mN. The recovery behavior after the load is removed is analyzed to derive the compression recovery rate. The load-compression displacement during this period is measured, and the compression recovery rate can be calculated using the following formula. The loading rate is 0.33 mN / sec. For example, a Fischerscope H-100 manufactured by Fischer is used as the micro-compression tester.

[0051] Compression recovery rate (%) = [L2 / L1] x 100 L1: Compression displacement from the load value for origin when applying a load to the reverse load value L2: Unloading displacement from the reverse load value when releasing the load to the load value for origin

[0052] From the viewpoint of further enhancing the dispersibility of the resin particles in the solvent, the particle diameter of the resin particles is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 3.0 μm or more, particularly preferably 5.0 μm or more, and is preferably 100 μm or less, more preferably 50 μm or less, even more preferably 30 μm or less, particularly preferably 20 μm or less.

[0053] The particle diameter of the resin particles means the diameter when the resin particles are spherical, and when the resin particles are other than spherical, means the diameter when the resin particles are assumed to be spherical with a volume equivalent to that of the resin particles.

[0054] The particle size of the resin particles is preferably an average particle size, and more preferably a number average particle size. The particle size of the resin particles can be measured using any particle size distribution measuring device. For example, it can be measured using a particle size distribution measuring device that uses the principles of laser light scattering, electrical resistance change, image analysis after imaging, etc. More specifically, as a method for measuring the particle size of the resin particles, a method can be mentioned in which the particle sizes of approximately 100,000 resin particles are measured using a particle size distribution measuring device (Beckman Coulter's "Multisizer 4") and the average value is calculated.

[0055] From the viewpoint of further improving the dispersibility of the resin particles in the solvent, the coefficient of variation (CV value) of the particle diameter of the resin particles is preferably 30% or less, more preferably 20% or less, and even more preferably 10% or less. The lower limit of the coefficient of variation (CV value) of the particle diameter of the resin particles is not particularly limited. The coefficient of variation (CV value) of the particle diameter of the resin particles may be 0% or more, or may be 1% or more. The range of the coefficient of variation (CV value) of the particle diameter of the resin particles can be set by appropriately selecting the lower limit value and the upper limit value.

[0056] The coefficient of variation (CV value) of the particle diameter of the resin particles can be measured as follows.

[0057] CV value (%) of the particle diameter of the resin particles = (ρ / Dn) × 100, where ρ is the standard deviation of the particle diameter of the resin particles, and Dn is the average particle diameter of the resin particles.

[0058] The shape of the resin particles is not particularly limited. The shape of the resin particles may be spherical, may be a shape other than spherical, or may be flat. From the viewpoint of further improving the dispersibility of the resin particles in a solvent, the shape of the resin particles is preferably spherical.

[0059] From the viewpoint of further enhancing the dispersibility of the resin particles in the solvent, the aspect ratio of the resin particles is preferably 1.5 or less, more preferably 1.3 or less, and even more preferably 1.1 or less. The lower limit of the aspect ratio of the resin particles is not particularly limited. The aspect ratio of the resin particles may be 1.0 or more, or may be 1.1 or more. From the viewpoint of further enhancing the dispersibility of the resin particles in the solvent, the aspect ratio of the resin particles is most preferably 1.0. The range of the aspect ratio of the resin particles can be set by appropriately selecting the lower limit and the upper limit.

[0060] The aspect ratio is expressed as the ratio of major axis to minor axis, and is preferably determined by observing 10 arbitrary resin particles under an electron microscope or an optical microscope, defining the maximum diameter and the minimum diameter as the major axis and the minor axis, respectively, and calculating the average value of the major axis / minor axis of each of the spherical resin particles.

[0061] From the viewpoint of preventing the resin particles from settling in the solvent and further increasing the dispersibility of the resin particles in the solvent, the specific gravity of the resin particles is preferably 1.6 or less, more preferably 1.5 or less, even more preferably 1.4 or less, and particularly preferably 1.3 or less. The specific gravity of the resin particles may be 0.8 or more, 0.90 or more, 0.95 or more, 0.98 or more, 0.99 or more, or 1.0 or more. The range of the specific gravity of the resin particles can be set by appropriately selecting the lower limit and the upper limit.

[0062] The resin particles are preferably used by dispersing them in a solvent. The resin particles are preferably used as a composition by dispersing them in a solvent. The solvent for dispersing the resin particles may be aqueous or oil-based. Examples of solvents for dispersing the resin particles include silicone, water, mineral oil, polyether derivatives; alcohols such as methanol, ethanol, isopropanol, and fluorine-containing alcohols; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran, diethyl ether, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, and cyclic ethers; esters such as acetate esters, pyruvate esters, 2-hydroxyisobutyric acid, and lactate esters; amides such as dimethylformamide; aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as octane and decane; and resins. Examples of the resins include rubber, vinyl resins, acrylic resins, urethane resins, melamine resins, polyester resins, polyol resins, engineering plastics, silicone resins, fluororesins, and epoxy resins. When the resin particles are used in a liquid state by dispersing them in a solvent, the solvent is preferably silicone, water, mineral oil, polyether derivatives, or the like. Compositions in which the resin particles are dispersed in these solvents are particularly suitable for use as lubricants, anti-tack agents, etc. When the resin particles are dispersed in a solvent and then the solvent is vaporized for use, the solvent is preferably an alcohol such as methanol, ethanol, isopropanol, or a fluorine-containing alcohol; a ketone such as acetone or methyl ethyl ketone; an ether such as tetrahydrofuran, diethyl ether, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, or a cyclic ether; an ester such as acetate ester, pyruvate ester, 2-hydroxyisobutyric acid, or lactate ester; an amide such as dimethylformamide; an aromatic hydrocarbon such as toluene or xylene; an aliphatic hydrocarbon such as octane or decane; or water. Compositions in which the resin particles are dispersed in these solvents are particularly suitable for use in inks, coating agents, paints, photoreceptors, etc.The composition in which the resin particles are dispersed in the resin is particularly suitable for use as a coating agent, paint, non-tackifier, anti-drip agent, and the like.

[0063] The composition containing the resin particles and a solvent may be applied using an inkjet device, screen printing, or a dispensing method. Generally, conventional composite particles containing fluorine-based resins tend to settle when dispersed in a solvent, making it difficult to improve inkjet ejection properties. On the other hand, the resin particles have the above-described structure, and therefore can improve inkjet ejection properties when dispersed in a solvent.

[0064] From the viewpoint of further enhancing the dispersibility of the resin particles in the solvent, the specific gravity of the solvent in which the resin particles are dispersed is preferably 0.5 or more, more preferably 0.7 or more, even more preferably 0.8 or more, and preferably 1.5 or less, more preferably 1.3 or less, even more preferably 1.1 or less.

[0065] This specification discloses a dispersion containing the above-mentioned resin particles and a solvent. Since specific resin particles are used in this dispersion, the resin particles have excellent dispersibility. From the viewpoint of further enhancing the dispersibility of the resin particles in the solvent, the resin particles are preferably dispersed in toluene or an epoxy resin. The dispersion may contain toluene or an epoxy resin. The dispersion is preferably a material for an insulating layer, as this effectively exhibits the effects of the present invention.

[0066] Each component of the resin particles will be described in detail below.

[0067] <Resin Particle Body> The resin particle has a resin particle body. The resin particle and the resin particle body contain a resin. In the resin particle, the resin particle body is a polymer of a polymerizable component. The polymerizable component contains a polymerizable compound having one or more ethylenically unsaturated groups. Specifically, the polymerizable component contains a polymerizable compound having one or more maleimide groups. From the viewpoint of effectively achieving the effects of the present invention, the polymerizable component preferably contains a polymerizable compound having two or more ethylenically unsaturated groups, and more preferably contains a polymerizable compound having two or more maleimide groups. From the viewpoint of effectively achieving the effects of the present invention, the resin particle body preferably contains a polymer of a polymerizable compound having one or more ethylenically unsaturated groups, and more preferably contains a polymer of a polymerizable compound having one or more maleimide groups. From the viewpoint of effectively exerting the effects of the present invention, it is preferable that the resin particle body contains a polymer of a polymerizable compound having two or more ethylenically unsaturated groups, and it is preferable that it contains a polymer of a polymerizable compound having two or more maleimide groups.

[0068] Examples of the polymerizable compound (monomer) having one or more ethylenically unsaturated groups include a polymerizable compound having one ethylenically unsaturated group and a polymerizable compound having two or more ethylenically unsaturated groups. The polymerizable compound having two or more ethylenically unsaturated groups may have 100 or less ethylenically unsaturated groups, or may have 10 or less ethylenically unsaturated groups. Examples of the polymerizable compound (monomer) having one or more maleimide groups include a polymerizable compound having one maleimide group and a polymerizable compound having two or more maleimide groups. The polymerizable compound having two or more maleimide groups may have 100 or less maleimide groups, or may have 10 or less maleimide groups. The polymerizable compound having one or more ethylenically unsaturated groups may be used alone or in combination of two or more. The polymerizable compound having one ethylenically unsaturated group may be used alone or in combination of two or more. The polymerizable compound having two or more ethylenically unsaturated groups may be used alone or in combination of two or more. The polymerizable compound having one or more maleimide groups may be used alone or in combination of two or more. The polymerizable compound having one maleimide group may be used alone or in combination of two or more. The polymerizable compound having two or more maleimide groups may be used alone or in combination of two or more. The range of the number of maleimide groups in the polymerizable compound having one or more maleimide groups (and the polymerizable compound having two or more maleimide groups) can be set by appropriately selecting the lower limit and upper limit described in the present specification. The range of the number of ethylenically unsaturated groups in the polymerizable compound having one or more ethylenically unsaturated groups (or the polymerizable compound having two or more ethylenically unsaturated groups) can be set by appropriately selecting the lower limit and upper limit described in the present specification.

[0069] The polymerizable compound (monomer) having one or more ethylenically unsaturated groups includes a polymerizable compound having one ethylenically unsaturated group and a polymerizable compound having two or more ethylenically unsaturated groups. The polymerizable compound having two or more ethylenically unsaturated groups may have 100 or less ethylenically unsaturated groups, or may have 10 or less ethylenically unsaturated groups.

[0070] Examples of the non-crosslinkable monomer include styrene-based monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride; alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, glycerol (meth)acrylate, and polyoxyethylene (meth)acrylate. nitrile-containing monomers such as (meth)acrylonitrile; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; acid vinyl esters such as vinyl acetate, vinyl butyrate, vinyl laurate, and vinyl stearate; unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; halogen-containing monomers such as trifluoromethyl (meth)acrylate, pentafluoroethyl (meth)acrylate, (perfluorohexyl)ethyl (meth)acrylate, vinyl chloride, vinyl fluoride, and chlorostyrene; and polymerizable compounds having one maleimide group.

[0071] Examples of the crosslinkable monomer include tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, and (poly)propylene glycol di(meth)acrylate. Examples of suitable polymerizable compounds include polyfunctional (meth)acrylates such as (meth)acrylate, (poly)tetramethylene glycol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate; silane-containing monomers such as triallyl (iso)cyanurate, triallyl trimellitate, divinylbenzene, diallyl phthalate, diallyl acrylamide, diallyl ether, γ-(meth)acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, and vinyltrimethoxysilane; and polymerizable compounds having two or more maleimide groups. The polymerizable compound having two or more maleimide groups may be a polymerizable compound having two maleimide groups or may be a bismaleimide compound. The polymerizable compound having two or more maleimide groups may have 100 or less maleimide groups, or may have 10 or less maleimide groups.

[0072]

[0033] From the viewpoint of achieving the effects of the present invention, particularly low dielectric properties, the polymerizable compound having an ethylenically unsaturated group (polymerizable component) includes a polymerizable compound having one or more maleimide groups. From the viewpoint of achieving the effects of the present invention more effectively, particularly low dielectric properties, the polymerizable compound having an ethylenically unsaturated group (polymerizable component) preferably includes a polymerizable compound having two or more maleimide groups, and more preferably includes a bismaleimide compound.

[0073] From the viewpoint of more effectively exhibiting solvent resistance and chemical resistance, the polymerizable component preferably contains a crosslinkable monomer (hereinafter, sometimes referred to as crosslinkable monomer (X)) different from the polymerizable compound having one or more maleimide groups. From the viewpoint of more effectively exhibiting solvent resistance and chemical resistance, the crosslinkable monomer (X) preferably contains divinylbenzene or a polymerizable compound having two or more (meth)acryloyl groups. The polymerizable compound having two or more (meth)acryloyl groups may have 100 or less methacryloyl groups, or may have 10 or less methacryloyl groups. The range of the number of (meth)acryloyl groups in the polymerizable compound having two or more (meth)acryloyl groups can be set by appropriately selecting the above lower limit and the above upper limit.

[0074] The resin particle bodies can be obtained by polymerizing the polymerizable compound having one or more ethylenically unsaturated groups by a known method, such as a suspension polymerization method in the presence of a radical polymerization initiator, or a method in which a polymerizable compound is swelled and polymerized together with a radical polymerization initiator using non-crosslinked seed particles.

[0075] The particle diameter of the resin particle body is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 3.0 μm or more, particularly preferably 5.0 μm or more, and is preferably 100 μm or less, more preferably 50 μm or less, even more preferably 30 μm or less, particularly preferably 20 μm or less. When the particle diameter of the resin particle body is not less than the above lower limit and not more than the above upper limit, the dispersibility of the resin particles in solvents and the water repellency can be further improved.

[0076] The particle diameter of the resin particle body means the diameter when the resin particle body is spherical, and when the resin particle body has a shape other than spherical, means the diameter when assumed to be a perfect sphere of equivalent volume.

[0077] The particle diameter of the resin particle body is preferably an average particle diameter, and more preferably a number average particle diameter. The particle diameter of the resin particle body can be measured using any particle size distribution measuring device. For example, it can be measured using a particle size distribution measuring device that uses the principles of laser light scattering, electrical resistance change, image analysis after imaging, etc. More specifically, as a method for measuring the particle diameter of the resin particle body, a method can be mentioned in which the particle diameters of approximately 100,000 resin particle bodies are measured using a particle size distribution measuring device (Beckman Coulter's "Multisizer 4") and the average particle diameter is calculated.

[0078] From the viewpoint of further improving the dispersibility of the resin particles in the solvent, the coefficient of variation (CV value) of the particle diameter of the resin particle body is preferably 30% or less, more preferably 20% or less, and even more preferably 10% or less. The lower limit of the coefficient of variation (CV value) of the particle diameter of the resin particle body is not particularly limited. The coefficient of variation (CV value) of the particle diameter of the resin particle body may be 0% or more, or may be 1% or more. The range of the coefficient of variation (CV value) of the particle diameter of the resin particle body can be set by appropriately selecting the lower limit value and the upper limit value.

[0079] The coefficient of variation (CV value) of the particle diameter of the resin particle body can be measured as follows.

[0080] CV value (%) of the particle diameter of the resin particle body = (ρ / Dn) × 100, where ρ: standard deviation of the particle diameter of the resin particle body, and Dn: average particle diameter of the resin particle body.

[0081] The shape of the resin particle body is not particularly limited, and may be spherical, or may be a shape other than spherical, such as flat.

[0082] In 100% by weight of the resin particles, the content of the resin particle body is preferably 40% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more, even more preferably 70% by weight or more, still more preferably 80% by weight or more, particularly preferably 90% by weight or more, most preferably 95% by weight or more, and is preferably 99.9% by weight or less, more preferably 99% by weight or less, and even more preferably 98% by weight or less. When the content of the resin particle body is not less than the above lower limit and not more than the above upper limit, the dispersibility of the resin particles in a solvent can be further improved.

[0083] The content of the polymerizable compound having one or more ethylenically unsaturated groups in 100% by weight of the polymerizable component is preferably 40% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more, even more preferably 70% by weight or more, even more preferably 80% by weight or more, particularly preferably 85% by weight or more, particularly preferably 90% by weight or more, most preferably 95% by weight or more, and preferably 100% by weight or less. When the content of the polymerizable compound having one or more ethylenically unsaturated groups is above the lower limit, solvent resistance and chemical resistance can be improved. The upper limit of the content of the polymerizable compound having one or more ethylenically unsaturated groups is not particularly limited. The content of the polymerizable compound having one or more ethylenically unsaturated groups in 100% by weight of the polymerizable component may be 100% by weight (total amount) or may be less than 100% by weight.

[0084] The content of the polymerizable compound having two or more ethylenically unsaturated groups in 100% by weight of the polymerizable component is preferably 40% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more, even more preferably 70% by weight or more, even more preferably 80% by weight or more, particularly preferably 85% by weight or more, particularly preferably 90% by weight or more, most preferably 95% by weight or more, and preferably 100% by weight or less. When the content of the polymerizable compound having two or more ethylenically unsaturated groups is equal to or greater than the lower limit, solvent resistance and chemical resistance can be improved. The upper limit of the content of the polymerizable compound having two or more ethylenically unsaturated groups is not particularly limited. The content of the polymerizable compound having two or more ethylenically unsaturated groups in 100% by weight of the polymerizable component may be 100% by weight (total amount) or less than 100% by weight.

[0085] The content of the polymerizable compound having one or more maleimide groups in 100% by weight of the polymerizable component is preferably 1% by weight or more, more preferably 5% by weight or more, even more preferably 10% by weight or more, even more preferably 20% by weight or more, particularly preferably 30% by weight or more, most preferably 50% by weight or more, and preferably 100% by weight or less. When the content of the polymerizable compound having one or more maleimide groups is equal to or greater than the lower limit, low dielectric properties can be more effectively exhibited. There is no particular upper limit to the content of the polymerizable compound having one or more maleimide groups. The content of the polymerizable compound having one or more maleimide groups in 100% by weight of the polymerizable component may be 100% by weight (total amount) or less than 100% by weight.

[0086] The content of the polymerizable compound having two or more maleimide groups in 100% by weight of the polymerizable component is preferably 1% by weight or more, more preferably 5% by weight or more, even more preferably 10% by weight or more, even more preferably 20% by weight or more, particularly preferably 30% by weight or more, most preferably 50% by weight or more, and preferably 100% by weight or less. When the content of the polymerizable compound having two or more maleimide groups is equal to or greater than the lower limit, low dielectric properties can be more effectively exhibited. There is no particular upper limit to the content of the polymerizable compound having two or more maleimide groups. The content of the polymerizable compound having two or more maleimide groups in 100% by weight of the polymerizable component may be 100% by weight (total amount) or less than 100% by weight.

[0087] When the polymerizable component contains the crosslinkable monomer (X), the content of the crosslinkable monomer (X) in 100% by weight of the polymerizable component is preferably greater than 0% by weight, more preferably 1% by weight or more, even more preferably 5% by weight or more, even more preferably 10% by weight or more, even more preferably 20% by weight or more, particularly preferably 30% by weight or more, particularly preferably 40% by weight or more, and most preferably 50% by weight or more. When the content of the crosslinkable monomer (X) is equal to or greater than the above lower limit (or exceeds the above lower limit), low thermal expansion properties can be more effectively exhibited. There is no particular upper limit for the content of the crosslinkable monomer (X). The content of the crosslinkable monomer (X) in 100% by weight of the polymerizable component may be 99% by weight or less, 95% by weight or less, 90% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, or 50% by weight or less. The range of the content of the crosslinkable monomer (X) in 100% by weight of the polymerizable component can be set by appropriately selecting the lower limit and the upper limit.

[0088] <Silica Particles> The resin particles include a plurality of silica particles.

[0089] In silica particles in which a portion of the silica particles is present on the surface (external) of the resin particle body, the volume of the portion present on the surface (external) of the resin particle body in 100% by volume of the silica particles is preferably 10% by volume or more, more preferably 20% by volume or more, and even more preferably 30% by volume or more. In 100% by volume of the silica particles, the volume of the portion present on the surface (external) of the resin particle body is preferably 99% by volume or less, more preferably 90% by volume or less, and even more preferably 80% by volume or less. When the volume of the portion present on the surface (external) of the resin particle body is above the lower limit and below the upper limit, low thermal expansion can be more effectively exhibited. The range of the volume of the portion present on the surface (external) of the resin particle body in 100% by volume of the silica particles can be set by appropriately selecting the lower limit and the upper limit.

[0090] From the viewpoint of more effectively exhibiting low thermal expansion, in the resin particles, the number of silica particles present on the surface (external) of the resin particle body, out of the total number of silica particles (100%), is preferably 5% or more, more preferably 10% or more, even more preferably 15% or more, and preferably 100% or less. Note that when looking at a single silica particle, if all or part of the silica particle is present (exposed) on the surface (external) of the resin particle body, the silica particle is judged to correspond to the silica particle present on the surface (external) of the resin particle body. When looking at a single silica particle, if at least part of the silica particle is present (external) on the surface (external) of the resin particle body, the silica particle is judged to correspond to the silica particle present on the surface (external) of the resin particle body. When looking at a single silica particle, if the silica particle is not entirely present on the surface (external) of the resin particle body, the silica particle is judged not to correspond to the silica particle present on the surface (external) of the resin particle body.

[0091] In the resin particles, the silica particles may be dispersed on the surface (external) of the resin particle body or may be unevenly distributed. From the viewpoint of more effectively exhibiting low thermal expansion, it is preferable that the silica particles are dispersed on the surface (external) of the resin particle body.

[0092] The particle diameter of the silica particles is preferably 10 nm or more, more preferably 20 nm or more, even more preferably 100 nm or more, and preferably 1.0 μm or less, more preferably less than 1.0 μm, even more preferably 500 nm or less, particularly preferably 400 nm or less, and most preferably 350 nm or less. When the particle diameter of the silica particles is above the lower limit and below the upper limit (or below the upper limit), aggregation of silica particles on the surface or inside of the resin particle body can be suppressed. Furthermore, when the particle diameter of the silica particles is below the upper limit (or below the upper limit), low thermal expansion can be more effectively exhibited. From the viewpoint of more effectively exhibiting low thermal expansion, it is particularly preferable that the particle diameter of the silica particles is 1.0 μm or less.

[0093] The particle diameter of the silica particles is preferably equal to or smaller than the particle diameter of the resin particles, and more preferably smaller than the particle diameter of the resin particles.The ratio of the particle diameter of the silica particles to the particle diameter of the resin particles is referred to as the ratio (particle diameter of silica particles / particle diameter of resin particles).The ratio (particle diameter of silica particles / particle diameter of resin particles) is preferably 0.001 or more, more preferably 0.01 or more, even more preferably 0.03 or more, and preferably 0.5 or less, more preferably 0.3 or less, even more preferably 0.1 or less, particularly preferably 0.06 or less.When the ratio (particle diameter of silica particles / particle diameter of resin particles) is equal to or greater than the lower limit and equal to or less than the upper limit, it is possible to prevent the silica particles from aggregating on the surface or inside of the resin particle body.

[0094] The particle size of the silica particles means the diameter when the silica particles are spherical, and when the silica particles are other than spherical, means the diameter when the silica particles are assumed to be spherical with a volume equivalent to that of the particles.

[0095] The particle size of the silica particles is preferably an average particle size, and more preferably a number average particle size. The particle size of the silica particles can be measured using any particle size distribution measuring device. For example, it can be measured using a particle size distribution measuring device that uses the principles of laser light scattering, electrical resistance change, image analysis after imaging, etc. More specifically, as a method for measuring the particle size of silica particles, a method can be mentioned in which the particle size of silica particles is measured using a particle size distribution measuring device ("LS13 320" manufactured by Beckman Coulter) and the average value is calculated. The particle size of the silica particles can also be measured by observing the cross section of the resin particles.

[0096] From the viewpoint of further improving the dispersibility of the resin particles in the solvent, the coefficient of variation (CV value) of the particle size of the silica particles is preferably 1% or more, preferably 30% or less, more preferably 20% or less, and even more preferably 10% or less. The range of the coefficient of variation (CV value) of the particle size of the silica particles can be set by appropriately selecting the lower limit and the upper limit.

[0097] The coefficient of variation (CV value) of the particle size of the silica particles can be measured as follows.

[0098] CV value (%) of the particle diameter of the silica particles = (ρ / Dn) × 100, where ρ is the standard deviation of the particle diameter of the silica particles, and Dn is the average particle diameter of the silica particles.

[0099] The shape of the silica particles is not particularly limited, and may be spherical, or may be a shape other than spherical, such as flat.

[0100] From the viewpoint of more effectively exhibiting low thermal expansion properties, it is preferable that the number of the silica particles present in the region (R2) from the surface of the resin particle body to the center up to 1 / 2 of the thickness is greater than the number of the silica particles present in the region (R1) from the center of the resin particle body to the surface up to 1 / 2 of the thickness. From the viewpoint of more effectively exhibiting low thermal expansion properties, it is preferable that the number of the silica particles present on the surface of the resin particle body is greater than the number of the silica particles present inside the resin particle body.

[0101] The number of silica particles present in the region (R1) and the region (R2) can be measured, for example, as follows.

[0102] The resin particles were added to an epoxy resin so that the resin particle content was 30% by weight, and dispersed to prepare a resin body for embedding resin particles for inspection. A cross section of the resin particle was cut out using a CP (Crosssection Polisher) (JEOL Ltd., "IB-09010CP") so as to pass through the vicinity of the center of the resin particles dispersed in the resin body for embedding resin particles for inspection. Then, using an FIB-SEM (FEI, "Helios Nanolab 650"), 10 resin particles were randomly selected under conditions of 10 kV and 200 pA, and the silica particles in each resin particle were observed. In the cross section of the resin particle, the number of silica particles present in a region (R2) extending from the surface to half the thickness of the resin particle body toward the center, and the number of silica particles present in a region (R1) extending from the center to half the thickness of the resin particle body toward the surface were counted, and the average was calculated.

[0103] The ratio of the number of silica particles present in the region (R2) to the number of silica particles present in the region (R1) is defined as the ratio (number of silica particles present in region (R2) / number of silica particles present in region (R1)). The ratio (number of silica particles present in region (R2) / number of silica particles present in region (R1)) is preferably 1.0 or more, more preferably 2.0 or more, even more preferably 3.0 or more, and particularly preferably 4.0 or more. When the ratio (number of silica particles present in region (R2) / number of silica particles present in region (R1)) is equal to or greater than the lower limit, the water repellency can be further increased and the dielectric loss tangent can be further reduced. The ratio (number of silica particles present in region (R2) / number of silica particles present in region (R1)) may be 100 or less, or may be 10 or less. The range of the ratio (number of silica particles present in region (R2) / number of silica particles present in region (R1)) can be set by appropriately selecting the lower limit and the upper limit.

[0104] The content of the silica particles in 100% by weight of the resin particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, even more preferably 1.0% by weight or more, and particularly preferably 3.0% by weight or more. The content of the silica particles in 100% by weight of the resin particles is preferably 35% by weight or less, more preferably 30% by weight or less, even more preferably 20% by weight or less, particularly preferably 15% by weight or less, and most preferably 10% by weight or less. When the content of the silica particles is above the lower limit and below the upper limit, low thermal expansion can be more effectively exhibited. When the content of the silica particles is below the upper limit, the dispersibility of the resin particles in the solvent can be further improved. The range of the content of the silica particles in 100% by weight of the resin particles can be set by appropriately selecting the lower limit and the upper limit.

[0105] The content of the silica particles relative to 100 parts by weight of the resin particle body is preferably 0.1 parts by weight or more, more preferably 0.5 parts by weight or more, even more preferably 1.0 parts by weight or more, particularly preferably 3.0 parts by weight or more, and most preferably 5.0 parts by weight or more. The content of the silica particles relative to 100 parts by weight of the resin particle body is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, even more preferably 15 parts by weight or less, and particularly preferably 10 parts by weight or less. When the content of the silica particles is above the lower limit, low thermal expansion can be more effectively exhibited. When the content of the silica particles is below the upper limit, the dispersibility of the resin particles in the solvent can be further improved. The range of the content of the silica particles relative to 100 parts by weight of the resin particle body can be set by appropriately selecting the lower limit and the upper limit.

[0106] <Other Components> The resin particles and the resin particle bodies may contain other components as necessary. Examples of the other components include dispersants, preservatives, polymerization inhibitors, polymerization initiators, colorants, and surfactants. Only one type of the other components may be used, or two or more types may be used in combination.

[0107] The resin particles may or may not contain a surfactant, and examples of the surfactant include anionic surfactants such as carboxylates, sulfonates, sulfates, and phosphates, cationic surfactants such as amine salts and ammonium salts, amphoteric surfactants, ester-type and ether-type nonionic surfactants, and fluorine-based surfactants such as per(poly)fluoroalkyls.

[0108] From the viewpoint of reducing the environmental load, it is preferable that the resin particles contain a surfactant in an amount of 1 wt% or less, or contain no surfactant, based on 100 wt% of the resin particles. When the resin particles contain the surfactant, the content of the surfactant is preferably 0.5 wt% or less, more preferably 0.1 wt% or less, and even more preferably 0.01 wt% or less, based on 100 wt% of the resin particles. From the viewpoint of reducing the environmental load, it is more preferable that the resin particles do not contain a surfactant, and the content of the surfactant may be 0 wt% (not contained) based on 100 wt% of the resin particles.

[0109] (Circuit board with insulating layer) The resin particles are preferably used to obtain a circuit board with an insulating layer (use of the resin particles in a circuit board with an insulating layer). The resin particles are preferably used as a component of the insulating layer in a circuit board with an insulating layer (use of the resin particles as a component of the insulating layer in a circuit board with an insulating layer). An example of the circuit board with an insulating layer is a circuit board with an insulating layer, which includes a circuit board and an insulating layer disposed on the surface of the circuit board, and the insulating layer contains the resin particles described above.

[0110] In the circuit board with an insulating layer, the insulating layer is preferably laminated on the surface of the circuit board on which the circuits are provided, and a portion of the insulating layer is preferably embedded between the circuits.

[0111] Specific examples of the circuit board with an insulating layer include a multilayer board and a multilayer printed wiring board.

[0112] An example of the multilayer substrate is a multilayer substrate including a circuit board and an insulating layer laminated on the circuit board. The insulating layer of the multilayer substrate contains the resin particles described above. The insulating layer is preferably laminated on the surface of the circuit board on which the circuits (metal layer) are provided. A portion of the insulating layer is preferably embedded between the circuits. The multilayer substrate preferably further includes a copper plating layer laminated on the surface of the insulating layer.

[0113] Another example of the multilayer substrate is a multilayer substrate including a circuit board, an insulating layer laminated on a surface of the circuit board, and copper foil laminated on a surface of the insulating layer opposite to the surface on which the circuit board is laminated.

[0114] Another example of the multilayer substrate is a multilayer substrate including a circuit board and a plurality of insulating layers laminated on a surface of the circuit board, at least one of the insulating layers disposed on the circuit board containing the resin particles, and preferably the multilayer substrate further includes a circuit laminated on at least one surface of the insulating layer.

[0115] The multilayer printed wiring board includes, for example, a circuit board, a plurality of insulating layers disposed on a surface of the circuit board, and a metal layer disposed between the plurality of insulating layers, and at least one of the insulating layers contains the resin particles.

[0116] FIG. 3 is a cross-sectional view schematically showing a multilayer printed wiring board using resin particles according to the first embodiment of the present invention.

[0117] In the multilayer printed wiring board 11 (circuit board with insulating layers) shown in FIG. 3, multiple insulating layers 13-16 are stacked on the top surface 12a of the circuit board 12. A metal layer 17 is formed in a partial region of the top surface 12a of the circuit board 12. Of the multiple insulating layers 13-16, the insulating layers 13-15 other than the insulating layer 16 located on the outer surface opposite the circuit board 12 have a metal layer 17 formed in a partial region of the top surface. The metal layer 17 is a circuit. The metal layer 17 is disposed between the circuit board 12 and the insulating layer 13, and between each of the stacked insulating layers 13-16. The lower metal layer 17 and the upper metal layer 17 are connected to each other by at least one of via hole connections and through-hole connections (not shown).

[0118] In the multilayer printed wiring board 11, the insulating layers 13 to 16 contain resin particles 1. Furthermore, in the multilayer printed wiring board 11, good insulating reliability is provided between the upper metal layer 17 and the lower metal layer 17 that are not connected by via hole connections or through hole connections (not shown). In this embodiment, all of the insulating layers 13 to 16 contain resin particles 1, but it is sufficient that at least one of the insulating layers 13 to 16 contains resin particles 1. Furthermore, resin particles such as resin particles 1A may be used instead of the resin particles 1. In FIG. 3, the resin particles 1 are shown in a schematic diagram.

[0119] The resin particles can also be used in copper-clad laminates. An example of the copper-clad laminate is a copper-clad laminate comprising a copper foil and an insulating layer laminated on one surface of the copper foil. The insulating layer of the copper-clad laminate contains the resin particles.

[0120] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0121] The following materials were prepared:

[0122] (Materials for Resin Particle Body) Maleimide compound (1) (N-alkylbismaleimide compound, "BMI-689" manufactured by Designer Molecules Inc.) Maleimide compound (2) ("BMI-1400" manufactured by Designer Molecules Inc.) Maleimide compound (3) (1,6-bismaleimide)hexane) Divinylbenzene ("DVB960" manufactured by NS Styrene Monomer Co., Ltd.) Tetramethylolpropane trimethacrylate ("A-TMMT" manufactured by Shin-Nakamura Chemical Co., Ltd.) Silica particles (1) ("Admafine" manufactured by Admatechs Co., Ltd., average particle diameter 0.3 μm) Silica particles (2) ("Admafine" manufactured by Admatechs Co., Ltd., average particle diameter 0.6 μm) Silica particles (3) ("Admafine" manufactured by Admatechs Co., Ltd., average particle diameter 2 μm)

[0123] Example 1 Preparation of Resin Particles: 50 parts by weight of an N-alkylbismaleimide compound were mixed with 49 parts by weight of divinylbenzene and 1 part by weight of silica particles (1) and stirred to obtain a monomer solution containing dispersed silica particles. Next, 1 part by weight of a radical polymerization initiator (tert-butyl-2-ethylperoxyhexanoate, NOF Corporation's "Perbutyl O") was added to the resulting monomer solution and stirred until uniform, obtaining a monomer mixture. 200 parts by weight of a 1.0 wt% aqueous solution of polyvinyl alcohol with a molecular weight of approximately 2000 dissolved in pure water was placed in a reactor. The resulting monomer mixture was then added and stirred until the monomer droplets reached the desired particle size. The mixture was then heated at 90°C for 9 hours to polymerize the monomer droplets, yielding particles. The resulting particles were washed three times with hot water and acetone, and then classified to recover the resin particles. In the obtained resin particles, in at least one silica particle, a portion of the silica particle was present inside the resin particle body, and a portion of the silica particle was present (exposed) on the surface (exterior) of the resin particle body.

[0124] Preparation of film: A composition was obtained by dispersing 10 parts by weight of the obtained resin particles in a mixture of 50 parts by weight of an epoxy resin (bisphenol A type epoxy resin, "jER-828" manufactured by Mitsubishi Chemical Corporation), 50 parts by weight of butyl glycidyl ether, and 1 part by weight of a cationic polymerization initiator ("Sanaid SI-60L" manufactured by Sanshin Chemical Industry Co., Ltd.). The obtained composition was applied to a substrate to a thickness of 100 μm and heated at 100° C. for 2 hours to obtain a film.

[0125] (Examples 2 to 15) Resin particles were prepared in the same manner as in Example 1, except that the type and content (wt%) of the material of the resin particle body and the type and content (wt%) of the silica particles were changed as shown in Tables 1 to 3. Films containing resin particles were prepared in the same manner as in Example 1, except that the obtained resin particles were used.

[0126] (Comparative Examples 1 to 3) Resin particles were prepared in the same manner as in Example 1, except that the type and content (wt%) of the material of the resin particle body was changed as shown in Table 4 and that silica particles were not used. A film containing resin particles was prepared in the same manner as in Example 1, except that the obtained resin particles were used.

[0127] Comparative Example 4: Silica particles (1) were prepared without using the material for the resin particle body. A film containing silica particles was produced in the same manner as in Example 1, except that the silica particles (1) were used instead of the resin particles.

[0128] Comparative Example 5: Silica particles (3) were prepared without using the material of the resin particle body. A film containing silica particles was produced in the same manner as in Example 1, except that the silica particles (3) were used instead of the resin particles.

[0129] (Evaluation) (1) Average particle size of resin particles, and average particle size of silica particles / average particle size of resin particles The average particle size of approximately 100,000 particles of the obtained resin particles was measured using a particle size distribution measuring device (Multisizer 4 manufactured by Beckman Coulter, Inc.) and the ratio of the average particle size of silica particles to the average particle size of resin particles (average particle size of silica particles / average particle size of resin particles) was also calculated.

[0130] (2) Dielectric Constant of Resin Particles (or Silica Particles) The dielectric constant of the obtained resin particles at 1 GHz was calculated using a dielectric constant measuring device (manufactured by AET Co., Ltd., using a powder measurement resonator). Note that in Comparative Examples 4 and 5, the dielectric constant of silica particles was evaluated instead of the resin particles.

[0131] (3) Dielectric Loss Tangent of Resin Particles (or Silica Particles) The dielectric loss tangent at 1 GHz of the obtained resin particles was calculated using a dielectric constant measuring device (manufactured by AET Co., Ltd., using a powder measurement resonator). Note that in Comparative Examples 4 and 5, the dielectric loss tangent of silica particles instead of resin particles was evaluated.

[0132] (4) Thermal Expansion Coefficient of Resin Particles (or Silica Particles) The thermal expansion coefficient of the obtained resin particles at 50°C to 150°C was evaluated as follows. Note that for Comparative Examples 4 and 5, the thermal expansion coefficient of silica particles was evaluated instead of resin particles. Using thermomechanical analysis (TMA), the resin particles (or silica particles) were held at 50°C for 5 minutes, and then heated from 50°C to 160°C at a heating rate of 5°C / min. The linear expansion coefficient from 50°C (at the start of heating) to 150°C (upon reaching 150°C) was calculated. A "TMA450" manufactured by TA Instruments was used for the thermomechanical analysis (TMA).

[0133] (5) Dielectric Constant of Film The dielectric constant of the obtained film at 1 GHz was calculated using a dielectric constant measuring device (manufactured by AET Co., Ltd., using a powder measurement resonator). The dielectric constant of the film was judged according to the following criteria.

[0134] [Evaluation criteria for film dielectric constant] ○○○: Dielectric constant is less than 2.50 F / m ○○: Dielectric constant is 2.50 F / m or more and less than 2.70 F / m ○: Dielectric constant is 2.70 F / m or more and less than 2.90 F / m ×: Dielectric constant is 2.90 F / m or more

[0135] (6) Dielectric Loss Tangent of Film The dielectric loss tangent of the obtained film at 1 GHz was calculated using a dielectric constant measuring device (manufactured by AET Co., Ltd., using a powder measurement resonator). The dielectric loss tangent of the film was evaluated according to the following criteria.

[0136] [Criteria for determining dielectric dissipation factor of film] ○○○: Dielectric dissipation factor is less than 0.005 ○○: Dielectric dissipation factor is 0.005 or more and less than 0.008 ○: Dielectric dissipation factor is 0.008 or more and less than 0.01 ×: Dielectric dissipation factor is 0.01 or more

[0137] (7) Thermal Expansion Coefficient of Film The thermal expansion coefficient of the obtained film from 50°C to 150°C was evaluated as follows. Using a thermomechanical analyzer (TMA), the film was held at 50°C for 5 minutes, and then heated from 50°C to 160°C at a temperature increase rate of 5°C / min. The linear expansion coefficient from 50°C to 150°C was calculated. A "TMA450" manufactured by TA Instruments was used for the thermomechanical analyzer (TMA). The thermal expansion coefficient of the film was determined according to the following criteria.

[0138] [Criteria for determining the thermal expansion coefficient of a film] ○○○: Thermal expansion coefficient is less than 80 ppm / °C. ○○: Thermal expansion coefficient is 80 ppm / °C or more and less than 110 ppm / °C. ○: Thermal expansion coefficient is 110 ppm / °C or more and less than 150 ppm / °C. ×: Thermal expansion coefficient is 150 ppm / °C or more

[0139] The composition of the resin particles (or the constitution of the silica particles) and the results are shown in Tables 1 to 4 below.

[0140]

[0141]

[0142]

[0143]

[0144] As shown in Table 4, the following results can be seen: Comparative Examples 1 to 3, which contained resin particles without silica particles, were inferior in low dielectric property and / or low thermal expansion property. Furthermore, Comparative Examples 4 and 5, which contained silica particles, were inferior in low dielectric property.

[0145] REFERENCE SIGNS LIST 1, 1A... resin particle 2... resin particle body 3, 3A... silica particle 11... multilayer printed wiring board (circuit board with insulating layer) 12... circuit board 12a... upper surface 13 to 16... insulating layer 17... metal layer

Claims

1. Resin particles comprising a resin particle body and a plurality of silica particles, the plurality of silica particles being present on the surface or inside of the resin particle body, the resin particle body being a polymer of a polymerizable component, and the polymerizable component comprising a polymerizable compound having one or more maleimide groups.

2. The resin particles according to claim 1, wherein the particle diameter of said resin particles is 0.5 μm or more.

3. The resin particles according to claim 1 or 2, wherein the particle diameter of the silica particles is 1.0 μm or less.

4. The resin particles according to any one of claims 1 to 3, wherein the ratio of the particle size of the silica particles to the particle size of the resin particles is 0.001 or more and 0.5 or less.

5. Resin particles according to any one of claims 1 to 4, wherein the content of said silica particles is 0.1% by weight or more and 20% by weight or less in 100% by weight of said resin particles.

6. Resin particles according to any one of claims 1 to 5, wherein the content of the polymerizable compound having one or more maleimide groups is 10% by weight or more relative to 100% by weight of the polymerizable component.

7. The resin particles according to any one of claims 1 to 6, wherein the polymerizable component contains a crosslinkable monomer different from the polymerizable compound having one or more maleimide groups.

8. The resin particles according to claim 7, wherein the crosslinkable monomer is divinylbenzene or a polymerizable compound having two or more (meth)acryloyl groups.

9. The resin particles according to claim 7 or 8, wherein the content of the crosslinkable monomer is 10% by weight or more in 100% by weight of the polymerizable component.

10. The resin particles according to any one of claims 1 to 9, wherein the resin particles have a thermal expansion coefficient of less than 150 ppm / °C at 50°C to 150°C.

11. The resin particles according to any one of claims 1 to 10, wherein the resin particles have a dielectric constant of 2.80 F / m or less, and a dielectric loss tangent of 0.01 or less.

12. A resin particle according to any one of claims 1 to 11, wherein in at least one of the plurality of silica particles, a portion of the silica particle is present inside the resin particle body and a portion of the silica particle is present on the surface of the resin particle body.

13. A circuit board with an insulating layer, comprising: a circuit board; and an insulating layer disposed on a surface of the circuit board, the insulating layer containing the resin particles according to any one of claims 1 to 12.

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