Methods for manufacturing coating agent preparation kits, coating agents, electronic substrates, and electronic component modules.

Abstract

This invention provides a coating agent preparation kit that can effectively obtain a coating agent layer with a desired thickness and can easily form a film. The coating agent preparation kit of this invention is for obtaining a coating agent by mixing, and comprises a first composition and a second composition. The first composition contains a curable compound that can be cured by ultraviolet light, heat, or moisture, and the second composition contains hollow particles.

Description

Technical Field

[0001] This invention relates to a coating agent preparation kit. Furthermore, this invention relates to a coating agent. Furthermore, this invention relates to an electronic substrate using the said coating agent. Furthermore, this invention relates to a method for manufacturing an electronic component module using the said coating agent. Background Technology

[0002] Electronic components, in which semiconductor elements and connecting terminals are mounted on a circuit board, are widely used. The circuit board and the electronic components are typically electrically connected using solder. Furthermore, to protect the electronic components from moisture and to prevent the formation of whiskers and short circuits associated with oxidation of the circuit board, a coating (coating film) formed from a coating agent is disposed on at least a portion of the surface of the electronic components.

[0003] For example, Patent Document 1 discloses an in-vehicle control device comprising: a circuit board; electronic components mounted on the circuit board; solder that makes electrical contact between the terminals of the electronic components and the circuit board; and a coating film that protects at least a portion of the circuit board. In the in-vehicle control device, the coating film covers the terminals and the solder, and the loss modulus of elasticity of the coating film at 125°C is 1.0 × 10⁻⁶. 5 Pa or above.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: WO2017 / 038343A1 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] An electronic substrate is formed by covering the surface of a solder portion formed from solder with a cured coating (film). The electronic substrate can be manufactured by applying a coating to the surface of the solder portion and then curing the coating. Conventionally, coatings containing a large amount of organic solvent are used as the coating. With conventional coatings containing a large amount of organic solvent, it is difficult to increase the thickness of the coating layer. Therefore, to obtain the desired thickness, the coating needs to be applied repeatedly. Furthermore, with conventional coatings containing a large amount of organic solvent, a drying process is required to allow the organic solvent to evaporate. Therefore, with conventional coatings containing a large amount of organic solvent, the manufacturing efficiency of the electronic substrate is reduced.

[0009] The object of this invention is to provide a coating agent preparation kit and coating agent that can readily produce a coating agent layer of desired thickness and easily form a film. Furthermore, the object of this invention is to provide an electronic substrate using the aforementioned coating agent and a method for manufacturing an electronic component module.

[0010] Technical means to solve technical problems

[0011] According to a broad aspect of the present invention, a coating agent preparation kit is provided for obtaining a coating agent by mixing, wherein the coating agent preparation kit has a first composition and a second composition, the first composition comprising a curable compound that can be cured by ultraviolet light, heat or moisture, and the second composition comprising hollow particles.

[0012] In a particular aspect of the coating agent preparation kit of the present invention, the curing compound has a viscosity of 50 mPa·s or more and 3000 mPa·s or less at 25°C.

[0013] In a particular aspect of the coating agent preparation kit of the present invention, the coating agent obtained by mixing the first composition and the second composition has a viscosity of 100 mPa·s or more and 30000 mPa·s or less at 25°C.

[0014] According to a broad aspect of the invention, a coating agent is provided comprising a curable compound that can be cured by ultraviolet light, heat or moisture, and hollow particles.

[0015] In a particular aspect of the coating agent of the present invention, the curing compound has a viscosity of 50 mPa·s or more and 3000 mPa·s or less at 25°C, and the coating agent has a viscosity of 100 mPa·s or more and 30000 mPa·s or less at 25°C.

[0016] In a particular aspect of the coating agent of the present invention, the hollow particles are spherical particles or porous hollow particles. When the spherical particles are included, the content of the spherical particles in 100% by weight of the coating agent is 0.5% by weight or more and 50% by weight or less. When the porous hollow particles are included, the content of the porous hollow particles in 100% by weight of the coating agent is 5% by weight or more and 40% by weight or less.

[0017] In a particular aspect of the coating agent of the present invention, the hollow particles comprise spherical particles and porous hollow particles, wherein the content of the spherical particles in 100% by weight of the coating agent is 0.5% by weight or more and 10% by weight or less, and the content of the porous hollow particles in 100% by weight of the coating agent is 5% by weight or more and 40% by weight or less.

[0018] In a particular aspect of the coating agent of the present invention, the hollow particles have a hollowness of 40% by volume or more and 99% by volume or less.

[0019] In a particular aspect of the coating agent of the present invention, the hollow particles comprise polyacrylonitrile or acrylic resin.

[0020] In a particular aspect of the coating agent of the present invention, the curing compound comprises a first curing compound that can be cured by ultraviolet light.

[0021] In a particular aspect of the coating agent of the present invention, the first curable compound may be cured by ultraviolet light and may be cured by heat or moisture.

[0022] In a particular aspect of the coating agent of the present invention, the coating agent is a coating agent for circuit boards.

[0023] According to a broad aspect of the present invention, an electronic substrate is provided, comprising: a circuit board, a solder portion disposed on the surface of the circuit board, and a coating covering the solder portion, the coating being a cured product of the coating agent.

[0024] In a particular aspect of the electronic substrate of the present invention, the electronic substrate includes electronic components mounted on the circuit board, and the circuit board and the electronic components are electrically connected through the solder portion.

[0025] In a particular aspect of the electronic substrate of the present invention, the hollow particles are unevenly distributed in the thickness direction of the coating and are more present on the surface side opposite to the solder portion side.

[0026] In a particular aspect of the electronic substrate of the present invention, the coating has a first layer and a second layer, wherein the hollow particle content in 100% by weight of the first layer is less than 1.0% by weight, and the hollow particle content in 100% by weight of the second layer is 1.0% by weight or more.

[0027] In a particular aspect of the electronic substrate of the present invention, in the coating, the first layer is closer to the solder portion side than the second layer.

[0028] According to a broad aspect of the present invention, a method for manufacturing an electronic component module is provided, comprising: a step of preparing an electronic component on which electronic components are mounted on a circuit board, and wherein the circuit board and the electronic components are electrically connected by a conductive adhesive portion; a step of disposing of a coating agent on the surface of the electronic component such that it at least covers the conductive adhesive portion; a step of forming a film by curing the coating agent; and a step of injection molding the electronic component with the film formed in a metal mold, and sealing the electronic component with the film formed with a thermoplastic resin.

[0029] In a particular aspect of the manufacturing method of the electronic component module of the present invention, the conductive adhesive portion is a solder portion.

[0030] Invention Effects

[0031] The coating agent preparation kit of the present invention is a coating agent preparation kit for obtaining a coating agent by mixing. The coating agent preparation kit of the present invention comprises a first composition and a second composition, the first composition comprising a curable compound that can be cured by ultraviolet light, heat, or moisture, and the second composition comprising hollow particles. In the coating agent preparation kit of the present invention, due to the aforementioned configuration, a coating agent layer having a desired thickness can be obtained well, and a film can be easily formed.

[0032] The coating agent of the present invention comprises a curable compound that can be cured by ultraviolet light, heat, or moisture, and hollow particles. Because of this composition, the coating agent of the present invention can readily produce a coating layer with a desired thickness and can easily form a film. Attached Figure Description

[0033] [ Figure 1 ] Figure 1 This is a schematic cross-sectional view of an electronic substrate using a coating agent according to one embodiment of the present invention. Detailed Implementation

[0034] The following describes the details of the present invention.

[0035] (Coating agent preparation kit and coating agent)

[0036] The coating agent preparation kit of the present invention is a coating agent preparation kit for obtaining a coating agent by mixing. The coating agent preparation kit of the present invention comprises a first composition and a second composition, the first composition comprising a curable compound that can be cured by ultraviolet light, heat, or moisture, and the second composition comprising hollow particles.

[0037] The coating agent of the present invention comprises a curable compound and hollow particles that can be cured by ultraviolet light, heat or moisture.

[0038] In the coating agent preparation kit and coating agent of the present invention, due to the aforementioned configuration, a coating agent layer with a desired thickness can be obtained well, and a film can be easily formed.

[0039] In conventional coating agents containing a significant amount of organic solvent, it is difficult to increase the thickness of the coating layer obtained by applying the coating agent. Therefore, to form a coating layer with the desired thickness, the coating agent needs to be applied repeatedly. Furthermore, in conventional coating agents containing a significant amount of solvent, a drying process is required to allow the solvent to evaporate. Therefore, in conventional coating agents containing a significant amount of solvent, the manufacturing efficiency of electronic substrates is reduced. In contrast, in the present invention, the coating agent can be solvent-free or have a reduced solvent content, thus obtaining a coating layer with the desired thickness and eliminating the need for a drying process. In the present invention, a thicker coating layer can be obtained. Furthermore, the coating layer can be rapidly cured by ultraviolet irradiation or the like, thus facilitating the formation of a film. Therefore, in the present invention, the manufacturing efficiency of electronic substrates can be improved.

[0040] Furthermore, sometimes the obtained electronic substrate and resin are injection molded, and the electronic components in the electronic substrate are sealed with resin. However, in conventional coatings, the thermal insulation of the coating is sometimes uneven. Therefore, in electronic substrates with coatings formed by conventional coatings, during injection molding, the heat of the molten resin is easily transferred to the solder through the parts of the coating with high thermal conductivity, and the solder sometimes partially remelts. In the case of solder remelting, electronic components may sometimes break.

[0041] In contrast, the coating agent preparation kit and coating agent of the present invention, having the aforementioned structure, can form a coating with uniform thermal insulation properties, thus suppressing damage to electronic components caused by localized remelting of the solder. In the present invention, for example, after the coating agent is applied to the surface of the solder portion, it is cured, thereby appropriately forming a coating with uniform thermal insulation properties. Therefore, even when injection molding is performed using an electronic substrate or the like with the coating, the solder is less prone to remelting, thus suppressing damage to electronic components.

[0042] Furthermore, in the coating agent preparation kit and coating agent of the present invention, due to the aforementioned structure, it is also possible to effectively suppress the damage of electronic components caused by heat conduction from the molten resin (resin used to seal electronic components) used in injection molding.

[0043] To reduce the thermal conductivity of the coating, foaming agents such as solid and liquid foaming agents are considered. However, when using only a foaming agent, the bubbles in the coating tend to become continuous rather than independent bubbles. Furthermore, it is difficult to control the size of the voids in the coating. In particular, the electrical resistance is significantly reduced in areas with large voids due to continuous bubbles.

[0044] In contrast, in the coating agent preparation kit and coating agent of the present invention, hollow particles are used, which allows for control of the size of the voids in the coating and makes it less likely to generate continuous bubbles.

[0045] In the coating agent preparation kit, a coating agent can be obtained by mixing the first composition and the second composition. The first composition is a first mixing material. The second composition is a second mixing material. In the coating agent preparation kit, a coating agent containing the curable compound and the hollow particles can be obtained by mixing the first composition and the second composition. The first composition is preferably contained in a first container. The second composition is preferably contained in a second container. The first composition may contain only the curable compound, or it may be a composition containing the curable compound, or it may contain components other than the curable compound. In this specification, the first mixing material containing only one type of the curable compound is also referred to as a composition. The second composition may contain only the hollow particles, or it may be a composition containing the hollow particles, or it may contain components other than the hollow particles. In this specification, the second mixing material containing only one type of the hollow particles is also referred to as a composition. The coating agent preparation kit may be a two-dosage kit having the first composition and the second composition, or it may be a three-dosage kit having a third composition contained in a third container in addition to the first composition and the second composition. In the case of a three-component coating agent preparation kit, the coating agent can be obtained by mixing the first composition, the second composition, and the third composition. From the viewpoint of good operability, the coating agent preparation kit is preferably a two-component kit having the first composition and the second composition.

[0046] The following describes the coating agent preparation kit and the components used in the coating agent of the present invention. It should be noted that, in the following description, "(meth)acrylic acid" refers to one or both of "acrylic acid" and "methacrylic acid," "(meth)acryloyl" refers to one or both of "acryloyl" and "methacryloyl," and "(meth)acrylate" refers to one or both of "acrylate" and "methacrylate." Acrylic acid compounds refer to (meth)acrylic acid compounds, acrylic acid resins refer to (meth)acrylic acid resins, and acrylate compounds refer to (meth)acrylate compounds.

[0047] <Cureable Compounds>

[0048] In the coating agent preparation kit, the first composition comprises a curable compound that can be cured by ultraviolet light, heat, or moisture. The coating agent comprises a curable compound that can be cured by ultraviolet light, heat, or moisture. One curable compound may be used, or two or more may be used in combination.

[0049] The curable compound can be a monomer, an oligomer, or a polymer. Preferably, the curable compound contains either a monomer or an oligomer, and more preferably, it contains both a monomer and an oligomer.

[0050] The curable compound may include curable compounds that can be cured by ultraviolet light (UV curable compounds), curable compounds that can be cured by heat (thermal curable compounds), and curable compounds that can be cured by moisture (moisture curable compounds).

[0051] The curable compound that can be cured by ultraviolet light has ultraviolet-curable functional groups. The curable compound that can be cured by heat has thermocurable functional groups. The curable compound that can be cured by moisture has moisture-curable functional groups.

[0052] Examples of the UV-curable functional groups include: olefinic unsaturated groups, epoxy groups, vinyl ether groups, glycidyl ether groups, and oxetyl groups. Examples of the olefinic unsaturated groups include (meth)acryloyl groups, vinyl groups, and allyl groups.

[0053] Examples of thermosetting functional groups include epoxy groups, carboxyl groups, hydroxyl groups, and isocyanate groups.

[0054] Examples of moisture-curing functional groups include hydrolyzable silyl groups, cyano(meth)acrylate groups, and isocyanate groups. Examples of hydrolyzable silyl groups include alkoxysilyl groups. Examples of alkoxysilyl groups include trialkoxysilyl groups such as trimethoxysilyl, triethoxysilyl, triisopropoxysilyl, and triphenoxysilyl; dialkoxysilyl groups such as propyldimethoxysilyl, methyldimethoxysilyl, and methyldiethoxysilyl; and monoalkoxysilyl groups such as dimethylmethoxysilyl and dimethylethoxysilyl.

[0055] From the viewpoint of improving the curing speed of the coating agent, the curing compound preferably includes a first curing compound that can be cured by ultraviolet light. The first curing compound has ultraviolet curable functional groups. The first curing compound can be a curing compound that can be cured by heat or moisture (first curing compound (A)) or a curing compound that cannot be cured by heat or moisture (first curing compound (B)).

[0056] From the viewpoint of improving the versatility of the coating agent, the first curing compound is preferably curable by heat or moisture. That is, the curing compound preferably contains a first curing compound (first curing compound (A)) that can be cured by ultraviolet light and by heat or moisture. The curing compound preferably contains a first curing compound (first curing compound (A)) having ultraviolet curable functional groups and heat curable functional groups or moisture curable functional groups. By giving the first curing compound curable functional groups other than ultraviolet curable functional groups, the coating agent can be cured efficiently even in areas where ultraviolet curing is difficult.

[0057] From the viewpoint of improving the versatility of the coating agent, the curing compound preferably comprises a first curing compound and a second curing compound that can be cured by heat or moisture. In this case, the first curing compound is preferably the first curing compound (B). Furthermore, in this case, the second curing compound is preferably a curing compound that does not have UV-curable functional groups, and more preferably a curing compound that cannot be cured by ultraviolet light.

[0058] Examples of the first curable compound include: urethane acrylate compounds, polyester acrylate compounds, epoxy acrylate compounds, polyether acrylate compounds, acrylic compounds containing (meth)acryloyl groups, polythiol compounds, and butadiene acrylate compounds. From the viewpoint of improving the adhesion between the circuit board and the hollow particles, the first curable compound is preferably an urethane acrylate compound.

[0059] The first curable compound (A) can be obtained by introducing a thermosetting functional group or a moisture-curing functional group into a first curable compound that does not have both thermosetting and moisture-curing functional groups. For example, the first curable compound (A) can be obtained by reacting the first curable compound that does not have both thermosetting and moisture-curing functional groups with a reactive agent capable of imparting moisture-curing or thermosetting properties. Examples of such reactive agents include: isocyanate compounds, organopolysiloxanes, silane coupling agents, cyanoacrylates, organic peroxides, polyamine compounds, imidazole compounds, isocyanate compounds, and thermo-cationic polymerization initiators.

[0060] Examples of the first curable compound (A) include: ultraviolet-curable compounds such as urethane acrylate compounds, polyester acrylate compounds, epoxy acrylate compounds, polyether acrylate compounds, acrylic compounds containing (meth)acryloyl groups, polythiols, and butadiene acrylate compounds, and compounds having thermosetting or moisture-curable functional groups such as moisture-curable cyanoacrylate groups and hydrolyzable silyl groups.

[0061] Examples of the first curable compound (B) include: ultraviolet-curable compounds such as urethane acrylate compounds, polyester acrylate compounds, epoxy acrylate compounds, polyether acrylate compounds, acrylic compounds containing (meth)acryloyl groups, polythiols, and butadiene acrylate compounds, which do not have both thermosetting and moisture-curing functional groups.

[0062] Examples of the second curing compound include moisture-curing polyurethane resins and resins containing hydrolyzable silyl groups. From the viewpoint of improving the curing speed of the coating agent, the second curing compound is more preferably a moisture-curing polyurethane resin. The moisture-curing polyurethane resin has urethane bonds and isocyanate groups, and the isocyanate groups react with moisture in the air or in the adhered material to cure.

[0063] The moisture-curing polyurethane resin may have only one isocyanate group or two or more isocyanate groups. Preferably, the moisture-curing polyurethane resin has isocyanate groups at both ends of the main chain.

[0064] The moisture-curing polyurethane resin can be obtained, for example, by reacting a polyol compound having two or more hydroxyl groups with a polyisocyanate compound having two or more isocyanate groups.

[0065] The reaction between the polyol compound and the polyisocyanate compound is preferably carried out in such a manner that the molar ratio (isocyanate group / hydroxyl group) of the isocyanate group (NCO group) of the polyisocyanate compound to the hydroxyl group (OH group) of the polyol compound is 2.0 or more and 2.5 or less.

[0066] As the polyol compound, conventionally known polyol compounds commonly used in the manufacture of polyurethane can be used. Examples of such polyol compounds include polyester polyols, polyether polyols, polyalkylene polyols, and polycarbonate polyols. Only one type of polyol compound may be used, or two or more may be used in combination.

[0067] Examples of polyester polyols include polyester polyols obtained by reacting a polycarboxylic acid with a polyol, and poly-ε-caprolactone polyols obtained by ring-opening polymerization of ε-caprolactone.

[0068] Examples of such polycarboxylic acids include: terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, decamethyldicarboxylic acid, and dodecamethyldicarboxylic acid.

[0069] Examples of such polyols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and cyclohexanediol.

[0070] Examples of the polyether polyols include: ethylene glycol, propylene glycol, ring-opening polymers of tetrahydrofuran, ring-opening polymers of 3-methyltetrahydrofuran, and random copolymers or block copolymers thereof or their derivatives, bisphenol-type polyoxyethylene modifiers, etc.

[0071] The bisphenol-type polyoxyethylene modifier is a polyether polyol obtained by adding an epoxide (e.g., ethylene oxide, propylene oxide, butane oxide, etc.) to the active hydrogen portion of a bisphenol-type molecular backbone. The bisphenol-type polyoxyethylene modifier can be a random copolymer or a block copolymer. Preferably, the bisphenol-type polyoxyethylene modifier has one or more epoxides added to both ends of the bisphenol-type molecular backbone. The bisphenol type is not particularly limited and examples include bisphenol A, bisphenol F, and bisphenol S. The preferred bisphenol type is bisphenol A.

[0072] Examples of polyalkylene polyols include, for example, polybutadiene polyols, hydrogenated polybutadiene polyols, and hydrogenated polyisoprene polyols.

[0073] Examples of polycarbonate polyols include polyhexamethylene carbonate polyol and polycyclohexanedimethyl carbonate polyol.

[0074] Examples of the polyisocyanate compounds include aromatic polyisocyanate compounds and aliphatic polyisocyanate compounds. One type of polyisocyanate compound may be used, or two or more may be used in combination.

[0075] Examples of such aromatic polyisocyanate compounds include: diphenylmethane diisocyanate, liquid-modified diphenylmethane diisocyanate, polymeric MDI, toluene diisocyanate, and naphthalene-1,5-diisocyanate.

[0076] Examples of such aliphatic polyisocyanate compounds include: hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, norbornene diisocyanate, transcyclohexane-1,4-diisocyanate, isophorone diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, cyclohexane diisocyanate, bis(isocyanate methyl)cyclohexane, and dicyclohexylmethane diisocyanate.

[0077] From the perspectives of low vapor pressure and toxicity, and ease of handling, the polyisocyanate compound is preferably diphenylmethane diisocyanate or a modified version thereof.

[0078] The curable compound may comprise a compound having the structure shown in formula (1).

[0079] MA-UAU-MA...(1)

[0080] In formula (1), MA represents a group containing a moisture-curing functional group, A represents a group containing an oily skeleton derived from hydroxylated vegetable oil, and U represents a group containing a carbamate bond. Examples of moisture-curing functional groups in MA in formula (1) include (meth)acryloyl and alkoxy groups.

[0081] The viscosity of the curable compound at 25°C is preferably 50 mPa·s or higher, more preferably 60 mPa·s or higher, even more preferably 100 mPa·s or higher, preferably 3000 mPa·s or lower, more preferably 2000 mPa·s or lower, even more preferably 1000 mPa·s or lower, and particularly preferably 500 mPa·s or lower. If the viscosity of the curable compound at 25°C is above the lower limit and below the upper limit, the separation caused by the difference in specific gravity between the curable compound and the hollow particles is effectively suppressed, thereby making it easy to uniformly disperse the hollow particles and effectively adjust the viscosity of the coating agent. As a result, a film of uniform thickness can be formed well, and the effects of the present invention can be more effectively achieved.

[0082] The viscosity of the curable compound at 25°C can be measured using an E-type viscometer (e.g., the "TVE22L" manufactured by Toki Sangyo Co., Ltd.) at 25°C and 5 rpm.

[0083] In the coating agent preparation kit, the content of the curing compound in 100% by weight of the first composition is preferably 50% by weight or more, more preferably 75% by weight or more, and even more preferably 90% by weight or more. When the content of the curing compound is above or below the lower limit, the effects of the present invention can be more effectively achieved. In the coating agent preparation kit, the content of the curing compound in 100% by weight of the first composition can be 100% by weight, less than 100% by weight, less than 100% by weight, less than 95% by weight, less than 90% by weight, or less than 85% by weight.

[0084] In the coating agent preparation kit, the content of the first curing compound in 100% by weight of the first composition is preferably 50% by weight or more, more preferably 75% by weight or more, preferably 100% by weight or less, and more preferably 95% by weight or less. If the content of the first curing compound is above the lower limit and below the upper limit, the effects of the present invention can be more effectively achieved.

[0085] In the coating agent preparation kit, the content of the second curing compound in 100% by weight of the first composition is preferably more than 0% by weight, more preferably more than 5% by weight, more preferably less than 50% by weight, and more preferably less than 25% by weight. If the content of the second curing compound is within the aforementioned range, the effects of the present invention can be more effectively achieved.

[0086] In the 100% by weight of the coating agent, the content of the curing compound is preferably 50% by weight or more, more preferably 60% by weight or more, preferably 95% by weight or less, and more preferably 80% by weight or less. If the content of the curing compound is above the lower limit and below the upper limit, the effects of the present invention can be more effectively achieved. It should be noted that when the curing compound includes both the first curing compound and the second curing compound, the content of the curing compound in 100% by weight of the coating agent represents the total content of the first curing compound and the second curing compound.

[0087] Of the 100% by weight of the coating agent, the content of the first curing compound is preferably 25% by weight or more, more preferably 50% by weight or more, preferably 95% by weight or less, and more preferably 80% by weight or less. If the content of the first curing compound is above the lower limit and below the upper limit, the effects of the present invention can be exerted more effectively.

[0088] In the 100% by weight of the coating agent, the content of the second curing compound is preferably more than 0% by weight, more preferably 5% by weight or more, more preferably 45% by weight or less, and more preferably 40% by weight or less. If the content of the second curing compound is within the aforementioned range, the effects of the present invention can be achieved more effectively.

[0089] Thickener

[0090] In the coating agent preparation kit, the first composition preferably contains a thickener. The coating agent preferably contains a thickener. By using the thickener, the dispersion stability of the curable compound and hollow particles in the coating agent can be further improved. Therefore, in the film obtained by curing the coating agent, the curable compound and hollow particles can exist in a better dispersed state, resulting in uniform thermal insulation of the coating. Only one type of thickener can be used, or two or more types can be used in combination.

[0091] Examples of thickeners include aliphatic amide compounds, oxidized polyethylene compounds, and polyether phosphate compounds.

[0092] From the viewpoint of more effectively utilizing the effects of the present invention, the thickener is preferably an aliphatic amide compound.

[0093] The aliphatic amide compound is a compound having -NH-CO- bonds. Examples of such aliphatic amide compounds include: reactants of fatty acids with aliphatic amines and / or alicyclic amines, and their oligomers. Compounds having amide bonds form a mesh-like network structure involving hydrogen bonds, and therefore it is believed that the formation of this network structure is related to the uniform dispersion of hollow particles.

[0094] The aliphatic amide compound is preferably an aliphatic amide compound having a fatty acid polyamide structure, wherein the fatty acid has an alkyl group having 8 to 30 carbon atoms. The alkyl group having 8 to 30 carbon atoms can be a straight-chain alkyl group or a branched alkyl group. Furthermore, the alkyl group having 8 to 30 carbon atoms can be a group linked to a long chain by carbon-carbon bonds through repetition.

[0095] Examples of aliphatic amide compounds include: saturated fatty acid monoamides such as lauryl amide and stearamide, unsaturated fatty acid monoamides such as oleamide, substituted amides such as N-lauryl lauryl amide and N-stearyl stearamide, hydroxymethyl amides such as hydroxymethyl stearamide, saturated fatty acid diamides such as methylene bis-stearamide, ethylene bis-lauryl amide and ethylene bis-hydroxy stearamide, unsaturated fatty acid diamides such as methylene bis-oleamide, aromatic diamides such as m-xylyl bis-stearamide, ethylene oxide adducts of fatty acid amides, fatty acid ester amides, fatty acid ethanol amides, substituted ureas such as N-butyl-N'-stearylurea, etc.

[0096] From the viewpoint of further improving the dispersibility of hollow particles, the aliphatic amide compound is preferably a saturated fatty acid monoamide.

[0097] Commercially available products can be used as the aliphatic amide compounds. Examples of commercially available aliphatic amide compounds include: DISPARLON 6900-20X, DISPARLON 6900-10X, DISPARLON A603-20X, DISPARLON A603-10X, DISPARLON A670-20M, DISPARLON 6810-20X, DISPARLON 6850-20X, DISPARLON 6820-20M, DISPARLON 6820-10M, DISPARLON FS-6010, DISPARLON PFA-131, DISPARLON PFA-231 (all manufactured by Kusunoki Chemical Co., Ltd.), FLOWNON RCM-210 (manufactured by Kyoei Chemical Co., Ltd.), and BYK-405 (manufactured by BYK-CHEMIE JAPAN Co., Ltd.).

[0098] The oxidized polyethylene compound is a compound obtained by contacting polyethylene with oxygen to modify a portion of the hydrogen in the methylene group into hydroxyl or carboxyl groups. The oxidized polyethylene compound has multiple hydroxyl or multiple carboxyl groups, and hydrogen bonds are formed between the oxygen and hydrogen atoms of the hydroxyl or carboxyl groups. Thus, the oxidized polyethylene compound forms a mesh-like network structure involving hydrogen bonds, and therefore, the formation of this network structure is considered to be related to the uniform dispersion of the hollow particles. In this invention, the material obtained by forming oxidized polyethylene into fine particles to form a colloidal wetted dispersion is particularly preferred.

[0099] Commercially available products can be used as the oxidized polyethylene compounds. Examples of commercially available oxidized polyethylene compounds include DISPARLON PF-920 (manufactured by Kusunoki Chemical Co., Ltd.) and FLO WNON SA-300H.

[0100] Examples of such polyether phosphate compounds include: monoesters or diesters such as polyoxyethylene alkyl ether phosphates, polyoxyethylene alkylphenyl ether phosphates, and higher alcohol phosphates, or their alkali metal salts, ammonium salts, and amine salts.

[0101] Commercially available products can be used as the polyether phosphate compound. Examples of commercially available polyether phosphate compounds include DISPARLON 3500 (manufactured by Kusunoki Chemical Co., Ltd.).

[0102] In the coating agent preparation kit, the content of the thickener in 100% by weight of the first composition is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, preferably 10% by weight or less, and more preferably 5% by weight or less. If the content of the thickener is above the lower limit and below the upper limit, the uniform dispersion of hollow particles in the obtained coating agent can be further improved, and as a result, the effects of the present invention can be more effectively exerted.

[0103] Of the 100% by weight of the coating agent, the content of the thickener is preferably 0.05% by weight or more, more preferably 0.25% by weight or more, even more preferably 0.5% by weight or more, preferably 10% by weight or less, more preferably 5% by weight or less, and even more preferably 4% by weight or less. If the content of the thickener is above the lower limit and below the upper limit, the effects of the present invention can be more effectively achieved.

[0104] Hollow particles

[0105] In the coating agent preparation kit, the second composition comprises hollow particles. The coating agent comprises hollow particles. By using the hollow particles, high thermal insulation properties can be imparted to the film formed by the coating agent. Only one type of hollow particle can be used, or two or more types can be used in combination.

[0106] Examples of hollow particles include spherical particles and porous hollow particles. A spherical particle is a particle with one cavity inside. A porous hollow particle is a particle with multiple cavities inside. These multiple cavities in a porous hollow particle can exist independently or partially connected.

[0107] From the viewpoint of further improving thermal insulation, the hollow particles are preferably spherical particles or porous hollow particles. From the viewpoint of further improving thermal insulation, the hollow particles preferably include at least one of spherical particles and porous hollow particles. From the viewpoint of increasing the hollowness ratio and further improving thermal insulation, the hollow particles more preferably include both spherical particles and porous hollow particles.

[0108] The hollow particle has a hollowness ratio preferably of 40% by volume or more, more preferably 45% by volume or more, more preferably 99% by volume or less, more preferably 80% by volume or less, even more preferably 70% by volume or less, and particularly preferably 60% by volume or less. If the hollow particle has a hollowness ratio above the lower limit and below the upper limit, the shape of the hollow particle is well maintained, and as a result, the effects of the present invention can be more effectively achieved.

[0109] The hollowness ratio of the hollow particles is calculated using the following formula (X).

[0110] Hollowness ratio (volume %) of hollow particles = (AB) / A × 100…(X)

[0111] A: The theoretical density (g / cm³) of the material constituting the hollow particles. 3 )

[0112] B: Density of hollow particles (g / cm³) 3 )

[0113] The specific gravity of the hollow particles is preferably 0.1 or higher, preferably 5.0 or lower, more preferably 4.0 or lower, even more preferably 3.0 or lower, even more preferably 2.0 or lower, and particularly preferably 1.5 or lower. If the specific gravity of the hollow particles is above the lower limit and below the upper limit, the uniform dispersion of the hollow particles in the coating agent can be further improved, and as a result, the effects of the present invention can be more effectively exerted.

[0114] The specific gravity of the hollow particles refers to their density relative to water (1.0 g / cm³). 3 The density of ).

[0115] The average particle size of the hollow particles is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, preferably 500 μm or less, more preferably 100 μm or less, and even more preferably 70 μm or less. If the average particle size of the hollow particles is above the lower limit and below the upper limit, the occurrence of slippage can be effectively suppressed.

[0116] The average particle size of the hollow particles refers to the average particle size (D50) obtained by measuring the particle size distribution of hollow particles in powder form using a laser diffraction scattering particle size distribution method.

[0117] The hollow particles can be resin-made hollow particles, inorganic hollow particles, or organic hollow particles with a glass shell. Examples of resin-made hollow particles include thermoplastic resin particles and thermosetting resin particles. Examples of inorganic hollow particles include glass particles, shirasuballoons, fly ash microspheres, aerogels, and ceramic particles.

[0118] From the viewpoint of improving mechanical and physical properties, the hollow particles are preferably thermoplastic resin particles, and more preferably vinyl ester resin particles. The material constituting the hollow particles is preferably a thermoplastic resin, and more preferably a vinyl ester resin. The hollow particles preferably contain a thermoplastic resin, and more preferably a vinyl ester resin.

[0119] Examples of monomers constituting the thermoplastic resin include compounds having a styrene backbone, compounds having (meth)acryloyl groups, vinyl acetate, vinyl ether compounds, vinyl ketone compounds, and olefin compounds. The thermoplastic resin may be a homopolymer using only one of the compounds (monomers), or a copolymer using two or more of the compounds (monomers).

[0120] Examples of compounds having a styrene skeleton include styrene, p-chlorostyrene, and α-methylstyrene.

[0121] Examples of compounds having a (meth)acryloyl group include (meth)acrylic acid and (meth)acrylates. Examples of (meth)acrylates include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, acrylate nitrile, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, and 2-ethylhexyl methacrylate.

[0122] Examples of vinyl ether compounds include vinyl methyl ether and vinyl isobutyl ether.

[0123] Examples of vinyl ketone compounds include vinyl methyl ketone, vinyl ethyl ketone, and vinyl isopropenone.

[0124] Examples of such olefin compounds include ethylene, propylene, and butadiene.

[0125] Furthermore, the material constituting the hollow particles can be a mixture of non-vinyl resins and vinyl resins, or a graft polymer obtained by polymerizing vinyl compounds in the presence of both non-vinyl resins and vinyl resins. Examples of non-vinyl resins include epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosin.

[0126] From the viewpoint of further improving the thermal insulation properties of the coating, the material constituting the hollow particles is preferably polyacrylonitrile or acrylic resin. From the viewpoint of further improving the thermal insulation properties of the coating, the hollow particles preferably contain polyacrylonitrile or acrylic resin.

[0127] The hollow particles can be either expansive or non-expandable. Expansive hollow particles refer to particles whose volume (or internal pores) increases due to external stimuli such as heat.

[0128] Commercially available products can be used as the hollow particles. Examples of commercially available resin-manufactured hollow particles include: ADVANCELL EM, HB (all manufactured by Sekisui Chemicals Co., Ltd.), EXPAN CEL U, E (all manufactured by JAPAN-FILLITE Co., Ltd.), MATSUMOTO MICROSPHER EF, FE (all manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.), etc. Examples of commercially available inorganic hollow particles include: SILINAX (manufactured by Nippon Steel Industries Co., Ltd.), E-SPHERES (manufactured by Taiyo Cement Co., Ltd.), HA RDLITE (manufactured by Showa Chemical Co., Ltd.), CENOLITE, MAARLITE, GLASS BALLOON (all manufactured by Tomoe Industries Co., Ltd.), etc.

[0129] In the coating agent preparation kit, the content of hollow particles in 100% by weight of the second composition is preferably 80% by weight or more, more preferably 90% by weight or more. The content of hollow particles in 100% by weight of the second composition can be 100% by weight, less than 100% by weight, less than 100% by weight, less than 90% by weight, or less than 80% by weight. When the content of hollow particles is above or below the lower limit, it can impart high thermal insulation to the film formed by the coating agent. Furthermore, it can further improve the uniform dispersion of hollow particles in the coating agent, enabling the formation of a film with uniform thickness. As a result, the effects of the present invention can be more effectively achieved.

[0130] In the 100% by weight of the coating agent, the content of hollow particles is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, even more preferably 5% by weight or more, even more preferably 10% by weight or more, particularly preferably 20% by weight or more, preferably 50% by weight or less, more preferably 45% by weight or less, and even more preferably 40% by weight or less. If the content of hollow particles is above the lower limit and below the upper limit, the film formed by the coating agent can be endowed with high thermal insulation properties. Furthermore, the uniform dispersion of hollow particles in the coating agent can be further improved, resulting in a film of uniform thickness that can be well formed. Consequently, the effects of the present invention can be more effectively achieved.

[0131] Of the 100% by weight of the coating agent, the content of the balloon particles is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, even more preferably 1% by weight or more, preferably 50% by weight or less, more preferably 40% by weight or less, even more preferably 30% by weight or less, and particularly preferably 10% by weight or less. If the content of the balloon particles is above the lower limit and below the upper limit, the coating formed by the coating agent can impart high thermal insulation properties. Furthermore, it can further improve the uniform dispersion of the hollow particles in the coating agent, enabling the formation of a coating of uniform thickness. As a result, the effects of the present invention can be more effectively achieved.

[0132] Of the 100% by weight of the coating agent, the content of the porous hollow particles is preferably 0.1% by weight or more, more preferably 3% by weight or more, further preferably 5% by weight or more, particularly preferably 10% by weight or more, and preferably 40% by weight or less. If the content of the porous hollow particles is above the lower limit and below the upper limit, the film formed by the coating agent can be endowed with high thermal insulation properties. Furthermore, the uniform dispersion of the hollow particles in the coating agent can be further improved, resulting in a film of uniform thickness that can be well formed. Consequently, the effects of the present invention can be more effectively achieved.

[0133] <Other Ingredients>

[0134] In the coating agent preparation kit, the first composition may contain other components different from the curing compound and the thickener. In the coating agent preparation kit, the second composition may contain components other than the hollow particles (other components). The coating agent may contain components other than the curing compound, the thickener, and the hollow particles (other components). Examples of such other components include: photoinitiators, sensitizers, leveling agents, fluorescent agents, antistatic agents, and fillers. Only one of these other components may be used, or two or more may be used in combination.

[0135] In the coating agent preparation kit, the first composition preferably does not contain organic solvents, or contains 50% by weight or less of organic solvents. If the first composition contains organic solvents, the content of organic solvents in 100% by weight of the first composition is preferably 50% by weight or less, more preferably 40% by weight or less, further preferably 30% by weight or less, more preferably 20% by weight or less, even more preferably 10% by weight or less, and particularly preferably 5% by weight or less. The content of organic solvents in 100% by weight of the first composition can exceed 0% by weight, can be 2.5% by weight or more, or can be 5% by weight or more. In the coating agent preparation kit, the first composition is most preferably free of organic solvents.

[0136] In the coating agent preparation kit, the second composition is preferably free of organic solvents, or contains organic solvents at a concentration of 20% by weight or less. If the second composition contains organic solvents, the content of organic solvents in 100% by weight of the second composition is preferably 20% by weight or less, more preferably 15% by weight or less, further preferably 10% by weight or less, and particularly preferably 5% by weight or less. The content of organic solvents in 100% by weight of the second composition can exceed 0% by weight, can be 2.5% by weight or more, or can be 5% by weight or more. Most preferably, the second composition in the coating agent preparation kit is free of organic solvents.

[0137] The coating agent is preferably free of organic solvents, or contains organic solvents at 50% by weight or less. If the coating agent contains organic solvents, the content of organic solvents in 100% by weight of the coating agent is preferably 50% by weight or less, more preferably 40% by weight or less, even more preferably 30% by weight or less, even more preferably 20% by weight or less, even more preferably 10% by weight or less, and particularly preferably 5% by weight or less. Most preferably, the coating agent is free of organic solvents.

[0138] Examples of organic solvents include: acetone, methyl ethyl ketone, alkyl cyclohexane, cyclohexene, ethylene glycol, propylene glycol, methanol, ethanol, isopropanol, butanol, benzene, toluene, xylene, ethyl acetate, and butyl acetate.

[0139] <Other details>

[0140] The coating agent preparation kit is preferably a coating agent preparation kit for circuit boards. The coating agent is preferably a coating agent for circuit boards. The coating agent is preferably used to cover conductive adhesive portions (preferably solder portions) disposed on the surface of a circuit board. The coating agent preparation kit is preferably a coating agent preparation kit for electronic substrate preparation. The coating agent is preferably a coating agent for electronic substrate preparation. The coating agent is preferably used to cover conductive adhesive portions (preferably solder portions) disposed on the surface of a circuit board in an electronic substrate. The coating agent preparation kit is preferably a coating agent preparation kit for covering solder. The coating agent is preferably a coating agent for covering solder. The coating agent preparation kit is preferably a coating agent preparation kit for forming a coating film covering solder. The coating agent is preferably a coating agent for forming a coating film covering solder.

[0141] In the 100% by weight of the coating agent, the total content of the curing compound and the hollow particles is preferably 80% by weight or more, more preferably 85% by weight or more, and even more preferably 90% by weight or more. If the total content is above the lower limit, the effects of the present invention can be more effectively achieved. It should be noted that in the 100% by weight of the coating agent, the total content of the curing compound and the hollow particles can be 100% by weight, less than 100% by weight, less than 90% by weight, or less than 80% by weight.

[0142] In the 100% by weight of the coating agent, the total content of the curing compound, the thickener, and the hollow particles is preferably 80% by weight or more, more preferably 85% by weight or more, and even more preferably 90% by weight or more. If the total content is above the lower limit, the effects of the present invention can be more effectively achieved. It should be noted that in the 100% by weight of the coating agent, the total content of the curing compound, the thickener, and the hollow particles can be 100% by weight, less than 100% by weight, less than 90% by weight, or less than 80% by weight.

[0143] In the coating agent preparation kit, the mixing ratio of the first composition and the second composition is not particularly limited. From the viewpoint of good mixing of the first composition and the second composition, it is preferable to mix the second composition with 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, more preferably 1 part by weight or less, and more preferably 0.8 parts by weight or less, relative to 1 part by weight of the first composition to obtain the coating agent.

[0144] In the coating agent preparation kit, the viscosity of the coating agent obtained by mixing the first composition and the second composition at 25°C is preferably 100 mPa·s or more, more preferably 200 mPa·s or more. In the coating agent preparation kit, the viscosity of the coating agent obtained by mixing the first composition and the second composition at 25°C is preferably 30000 mPa·s or less, more preferably 20000 mPa·s or less, further preferably 10000 mPa·s or less, and particularly preferably 7500 mPa·s or less. When the viscosity is above or below the lower limit, the coating shape of the coating agent disposed on the circuit board, etc., can be well maintained, and a film of uniform thickness can be well formed. If the viscosity is below the upper limit, the coating agent can be well sprayed from the dispenser.

[0145] The viscosity of the coating agent at 25°C is preferably 100 mPa·s or more, more preferably 200 mPa·s or more, preferably 30,000 mPa·s or less, more preferably 20,000 mPa·s or less, further preferably 10,000 mPa·s or less, and particularly preferably 7,500 mPa·s or less. When the viscosity is above or below the lower limit, the coating shape of the coating agent disposed on the circuit board can be well maintained, and a film of uniform thickness can be well formed. If the viscosity is below the upper limit, the coating agent can be well sprayed from the dispenser.

[0146] The viscosity of the coating agent at 25°C can be measured using an E-type viscometer (e.g., the "TVE22L" manufactured by Toki Sangyo Co., Ltd.) at 25°C and 5 rpm. Furthermore, the viscosity of the coating agent at 25°C is measured within 30 minutes of the preparation of the coating agent.

[0147] The coating agent preparation kit can be obtained, for example, by containing the first composition in a first container and the second composition in a second container. The coating agent can be obtained, for example, by mixing the first composition and the second composition. It should be noted that the coating agent can be obtained by mixing the curing compound, the thickener, the hollow particles, and other components as needed.

[0148] By curing the coating agent, a film (a cured coating agent) can be obtained. The curing method of the coating agent can be appropriately modified according to the type of curable compound contained in the coating agent.

[0149] (Electronic substrate and its manufacturing method)

[0150] The electronic substrate of the present invention includes a circuit substrate, a solder portion disposed on the surface of the circuit substrate, and a coating covering the solder portion, wherein the coating is a cured product of the coating agent.

[0151] Electronic components such as semiconductor chips can also be mounted on the circuit board. The coating agent is applied to the surface where soldering is performed for electrical connection between the electronic components and the circuit board, and the coating agent is cured to form a film.

[0152] The electronic substrate may or may not include electronic components. Preferably, the electronic substrate includes electronic components mounted on a circuit board. Preferably, the circuit board and the electronic components are electrically connected via solder joints. The electronic components are preferably mounted on the circuit board. Examples of such electronic components include semiconductor devices, resistor chips, capacitors, and external connection terminals.

[0153] Figure 1 This is a schematic cross-sectional view of an electronic substrate using a coating agent according to one embodiment of the present invention.

[0154] Figure 1 The electronic substrate 1 shown includes a circuit board 2, a solder portion 3 disposed on the surface of the circuit board 2, a coating 4 covering the solder portion 3, and electronic components 5. The coating 4 is also disposed on a portion of the surface of the circuit board 2. In the electronic substrate 1, the circuit board 2 and the electronic components 5 are electrically connected through the solder portion 3.

[0155] In the electronic substrate, the coating may cover only a portion of the surface of the solder portion, or it may cover the entire surface of the solder portion. Preferably, the coating is configured to cover the solder portion. Similarly, in the electronic substrate, the coating may cover only a portion of the surface of the circuit board, or it may cover the entire surface of the circuit board.

[0156] The electronic substrate is preferably an electronic substrate constituting an electronic control unit (ECU). Electronic components such as semiconductor elements, resistor chips, capacitors, and external connection terminals are mounted on an electronic substrate such as a wiring substrate. Electronic components, electrically connected to the electronic substrate and each electronic component using conductive bonding components such as solder, are modularized, thereby enabling the fabrication of electronic control units. The electronic control unit is preferably an electronic control unit for aircraft or automobiles, and more preferably an electronic control unit related to sensors.

[0157] The manufacturing method of the electronic substrate is not particularly limited. The manufacturing method of the electronic substrate preferably includes the following steps: (1) preparing an electronic component on which electronic components are mounted on a circuit board and the circuit board and the electronic components are electrically connected by solder portions; (2) applying the coating agent to the surface of the electronic component in a manner that at least covers the solder portions; and (3) forming a coating film by curing the coating agent.

[0158] Examples of methods for applying the coating agent to the surface of the electronic component include: coating using a dispenser, impregnation, etc. The thickness of the coating layer obtained by applying the coating agent to the surface of the electronic component is not particularly limited. The thickness of the coating layer can be 50 μm or more, 100 μm or more, 150 μm or more, 200 μm or more, 1000 μm or less, or 500 μm or less. In this invention, a relatively thick coating layer can be obtained well.

[0159] The method for curing the coating agent can be appropriately modified depending on the type of curing compound contained in the coating agent. Examples of methods for curing the coating agent include: irradiating the coating agent (coating agent layer) with ultraviolet light, heating the coating agent (coating agent layer), and allowing the coating agent to stand and cure naturally after preparation. The irradiation intensity when irradiating the coating agent with ultraviolet light and the heating temperature when heating the coating agent are appropriately set according to the type of curing compound.

[0160] In the electronic substrate, it is preferable that the hollow particles have a concentration gradient in the thickness direction of the coating. In the electronic substrate, it is preferable that the hollow particles are unevenly distributed in the thickness direction of the coating, with a higher concentration on the surface opposite to the solder portion side. In the electronic substrate, it is preferable that the content of hollow particles in the region with a thickness of 1 / 2 thickness from the outer surface of the coating towards the inner side is greater than the content of hollow particles in the region with a thickness of 1 / 2 thickness from the inner surface of the coating towards the outer side. In this case, the insulation resistance can be further improved. It should be noted that the inner surface of the coating refers to the surface of the coating on the solder portion side (circuit board side), and the outer surface of the coating refers to the surface of the coating opposite to the solder portion side (circuit board side).

[0161] The coating can have a single-layer structure, a two-layer structure, or a structure with more than two layers. By having a coating with two or more layers, a good concentration gradient of hollow particles can be achieved along the thickness direction of the coating.

[0162] Preferably, the coating has a first layer and a second layer, wherein the content of hollow particles in 100% by weight of the first layer is less than the content of hollow particles in 100% by weight of the second layer. Preferably, the coating has a first layer and a second layer, wherein the content of hollow particles in 100% by weight of the first layer is less than 1.0% by weight, and the content of hollow particles in 100% by weight of the second layer is 1.0% by weight or more. In this case, the first layer is a layer with a hollow particle content of less than 1.0% by weight, and the second layer is a layer with a hollow particle content of 1.0% by weight or more. By using multiple coating agents with different compositions, a coating having a first layer and a second layer can be formed. By having the coating having both the first layer and the second layer, the insulation resistance can be further improved.

[0163] In the coating, the first layer is preferably located closer to the solder portion than the second layer. Preferably, the first layer is located on the inner surface of the coating, and the second layer is located on the outer surface. In this case, the insulation resistance can be further improved.

[0164] The first layer preferably does not contain the hollow particles, or contains less than 1.0% by weight of the hollow particles. If the first layer contains the hollow particles, the content of the hollow particles in 100% by weight of the first layer is preferably less than 1.0% by weight, more preferably less than 0.5% by weight. If the content of the hollow particles is below or below the upper limit, the insulation resistance can be further improved. Most preferably, the first layer does not contain the hollow particles.

[0165] In the second layer (100% by weight), the content of hollow particles is preferably 5% by weight or more, more preferably 10% by weight or more, even more preferably 20% by weight or more, preferably 50% by weight or less, more preferably 45% by weight or less, and even more preferably 40% by weight or less. If the content of hollow particles is above the lower limit and below the upper limit, the insulation resistance can be further improved.

[0166] The absolute value of the difference between the content of hollow particles in 100% by weight of the first layer and the content of hollow particles in 100% by weight of the second layer is preferably 5% by weight or more, more preferably 10% by weight or more, more preferably 50% by weight or less, and more preferably 40% by weight or less. If the absolute value of the difference in the content of hollow particles is above the lower limit and below the upper limit, the insulation resistance and thermal insulation properties can be further improved.

[0167] From the viewpoint of further improving insulation resistance, the thickness of the first layer is preferably 10 μm or more, more preferably 50 μm or more, more preferably 250 μm or less, and more preferably 100 μm or less.

[0168] From the viewpoint of further improving thermal insulation, the thickness of the second layer is preferably 40 μm or more, more preferably 50 μm or more, preferably 750 μm or less, and more preferably 400 μm or less.

[0169] From the viewpoint of ensuring good sealing of electronic components, the thickness of the coating is preferably 50 μm or more, more preferably 100 μm or more, more preferably 1000 μm or less, and more preferably 500 μm or less.

[0170] In the electronic substrate, an insulating layer may also be provided on the surface of the solder portion. The electronic substrate may also have an insulating layer between the solder portion and the coating. In this case, the insulation resistance can be further improved in the electronic substrate and electronic component modules.

[0171] (Electronic component modules and their manufacturing methods)

[0172] To protect electronic components, electronic substrates housing the components are typically housed within a frame and integrated into an electronic component module. In recent years, there has been a demand for miniaturized electronic component modules, replacing the frame-based housing with integrated modules that seal the electronic components themselves with thermoplastic resin. These modules are manufactured by injection molding (in-mold molding) after the electronic components are placed in a mold. However, with conventional coating agents, during injection molding, heat from the molten thermoplastic resin is transferred to the electronic components, sometimes causing conductive bonding components such as solder to remelt, and sometimes resulting in component breakage due to partial solder remelting. In contrast, this invention utilizes a coating agent to form a uniformly insulating film, thus preventing heat transfer to the solder and suppressing component breakage. It should be noted that in this invention, sealing electronic components with thermoplastic resin refers to integrating or protecting electronic components, sensors, and external connection terminals with thermoplastic resin. Parts of the substrate, sensors, cables, etc., that are not covered by thermoplastic resin may also exist.

[0173] The electronic component module includes: an electronic component on which electronic elements are mounted on a circuit board, and the circuit board and the electronic elements are electrically connected by a conductive adhesive portion; a coating that at least covers the conductive adhesive portion; and a thermoplastic resin portion that seals the electronic component. In the electronic component module, the coating is a cured product of the coating agent. In the electronic component module, the conductive adhesive portion is formed by a conductive adhesive component. In the electronic component module, the thermoplastic resin portion is formed by a thermoplastic resin.

[0174] Examples of such electronic components include semiconductor elements, resistor chips, capacitors, and external connection terminals.

[0175] Examples of conductive adhesive components include resins containing conductive fillers and solders. Solder is preferred as the conductive adhesive component. Therefore, the conductive adhesive portion formed by the conductive adhesive component is preferably a solder portion. The solder only needs to contain tin (Sn). Examples of solders include Sn-Pb alloys, Sn-Ag-Cu alloys, Sn-Zn-Bi alloys, and Sn-Zn-Al alloys. From the viewpoint of environmental regulations, lead-free solders are preferred, and Sn-Ag-Cu alloys, Sn-Zn-Bi alloys, or Sn-Zn-Al alloys are more preferred.

[0176] Examples of resins containing the conductive filler include: thermosetting resins such as epoxy resins and phenolic resins, as well as thermoplastic resins such as polyester resins, polyolefin resins, polyurethane resins, and polycarbonate resins. Examples of conductive fillers in resins containing the conductive filler include gold, silver, copper, nickel, and aluminum.

[0177] From the viewpoint of improving operability when electrically connecting circuit boards to electronic components, the melting point of the conductive adhesive component is preferably 250°C or lower, more preferably 220°C or lower, even more preferably 200°C or lower, and particularly preferably 190°C or lower. It should be noted that when using a thermosetting resin or the like as the resin containing the conductive filler, if the melting point of the thermosetting resin cannot be determined, the heat resistance temperature is set as the melting point of the conductive adhesive component.

[0178] There are no particular limitations on the thermoplastic resin used for sealing electronic components, as long as it is an injection-moldable thermoplastic resin. Examples of such thermoplastic resins include: polyacetal resins, polyamide resins, polycarbonate resins, polybutylene terephthalate resins, polyethylene terephthalate resins, polyphenylene sulfide resins, acrylic resins, and ABS resins. From the viewpoint of achieving good formability and mechanical and physical properties, polybutylene terephthalate resin is preferred.

[0179] The manufacturing method of the electronic component module is not limited. Preferably, the manufacturing method of the electronic component module includes the following steps: (1) preparing an electronic component on which electronic components are mounted on a circuit board and the circuit board and the electronic components are electrically connected by a conductive adhesive portion; (2) applying the coating agent to the surface of the electronic component in a manner that at least covers the conductive adhesive portion; (3) forming a film by curing the coating agent; and (4) placing the electronic component with the film formed in a mold and performing injection molding, and sealing the electronic component with the film formed with a thermoplastic resin.

[0180] As the electronic component prepared in (1), an electronic component manufactured by a conventionally known method for manufacturing electronic components can be used.

[0181] In (2), methods for applying the coating agent to the surface of the electronic component include applying it using a dispenser and applying it by immersion. From the viewpoint of protecting the electronic component from heat, the coating agent is preferably applied in a manner that covers both the conductive adhesive portion and the entire circuit board on which the electronic component is mounted. The thickness of the coating agent layer obtained by applying the coating agent to the surface of the electronic component is not particularly limited. The thickness of the coating agent layer can be 50 μm or more, 100 μm or more, 150 μm or more, 200 μm or more, 1000 μm or less, or 500 μm or less. In this invention, a relatively thick coating agent layer can be obtained well.

[0182] In step (3), the method for curing the coating agent can be appropriately modified depending on the type of curing compound contained in the coating agent. Examples of methods for curing the coating agent include irradiating the coating agent (coating agent layer) with ultraviolet light, heating the coating agent (coating agent layer), and allowing the coating agent to cure naturally after preparation. The irradiation intensity when irradiating the coating agent with ultraviolet light and the heating temperature when heating the coating agent are appropriately set according to the type of curing compound.

[0183] In (4), insert injection molding is an example of a method for sealing electronic components by injection molding. The insert injection molding can be performed once or multiple times. In the case of performing the insert injection molding multiple times, it is preferable to use multiple thermoplastic resins with different molding temperatures.

[0184] This allows for the manufacture of electronic component modules with the desired shape.

[0185] The present invention will now be specifically described with reference to embodiments and comparative examples. The present invention is not limited to the embodiments described below.

[0186] Prepare the following materials.

[0187] (Curing compounds)

[0188] Curable compound 1 that can be cured by ultraviolet light (SANYU-REC "MX-313", viscosity at 25°C: 3000 mPa·s)

[0189] Curable compound 2 (SANYU-REC "E-800", viscosity at 25°C: 190 mPa·s) that can be cured by heat.

[0190] Curable compound 3 (SANYU-REC "MX-300L", viscosity at 25°C: 60 mPa·s) that can be cured by ultraviolet light or moisture.

[0191] Curable compound 4 that can be cured by ultraviolet light (NSC-7312 manufactured by Nippon Seika Co., Ltd., viscosity at 25°C: 19 mPa·s).

[0192] UV-curable compound 5 (1 part by weight of "Ebecryl 3700" manufactured by DAICL-ALLNEX and 1 part by weight of "Omnirad TPO H" manufactured by IGM Resins, viscosity at 25°C: 4000 mPa·s).

[0193] The viscosity of the curable compound at 25°C was measured using an E-type viscometer (Toki Sangyo Co., Ltd. "TVE22L") at 25°C and 5 rpm.

[0194] (Thickener)

[0195] Aliphatic amide compound 1 (DISPARLON PFA-131 manufactured by Kusumoto Chemical Co., Ltd.)

[0196] Aliphatic amide compound 2 ("FLOWNON RCM-210" manufactured by Kyoei Chemical Co., Ltd.)

[0197] (Hollow particles)

[0198] Hollow Particles 1 (Sekisui Chemicals Co., Ltd., "ADVANCELL HB2051", porous hollow particles, raw material: polyacrylonitrile, specific gravity: 0.4 g / cm³) 3 Hollowness ratio: 50% by volume; Average particle size: 20 μm

[0199] Hollow particles 2 (POTTERS-BALLOTINI "Q-cel 7040s" capsule particles, raw material: Na borosilicate glass particles, specific gravity: 0.4 g / cm³) 3 Average particle size: 45μm

[0200] Hollow Particle 3 (Sekisui Chemicals Co., Ltd. "ADVANCEL EM101", capsule particles, raw material: polyacrylonitrile, specific gravity: 0.02 g / cm³) 3 Hollowness ratio: 98% by volume; Average particle size: 100 μm

[0201] (Example 1)

[0202] (1) Preparation of the coating agent preparation kit

[0203] A mixture of 72.7 parts by weight of curable compound 1 and 2.3 parts by weight of aliphatic amide compound 1 is contained in a first container to obtain a first composition contained in the first container. 25 parts by weight of hollow particles 1 are contained in a second container to obtain a second composition contained in the second container. Thus, a coating agent preparation kit having the first composition and the second composition is prepared.

[0204] (2) Preparation of coating agent

[0205] The first and second compositions from the obtained coating agent preparation kit are mixed to prepare a coating agent containing each component in the amounts shown in Table 1 below.

[0206] (3) Fabrication of electronic substrates

[0207] The coating agent was weighed using a pipette and applied to the substrate to achieve a coating layer thickness of 200 μm. The coating layer was then irradiated for 1 minute at an intensity of 140 mW / cm². 2 Ultraviolet light is used to cure the coating layer. This process is then used to prepare the electronic substrate.

[0208] (4) Fabrication of electronic component modules

[0209] The obtained electronic substrate is placed in a mold for insert injection molding and injection molding is performed to obtain an electronic component module.

[0210] (Examples 2-15)

[0211] The first and second compositions were prepared such that the coating agent obtained by mixing the first and second compositions contained each component in the amounts shown in Tables 1 to 3 below. Otherwise, a coating agent preparation kit was prepared in the same manner as in Example 1. The first and second compositions from the obtained coating agent preparation kit were mixed to prepare a coating agent containing each component in the amounts shown in Tables 1 to 3 below. Furthermore, except for using the obtained coating agent, an electronic substrate and an electronic component module were obtained in the same manner as in Example 1.

[0212] (Comparative Examples 1-6)

[0213] The electronic substrate and electronic component module were obtained by using the curing compound or a mixture of curing compound and thickener shown in Table 4 below as the coating agent, otherwise operated in the same manner as in Example 1.

[0214] (evaluate)

[0215] (1) Viscosity of the coating agent at 25°C

[0216] The viscosity of the coating agent at 25°C was measured using an E-type viscometer (Toki Sangyo Co., Ltd. "TVE22L") at 25°C and 5 rpm. It should be noted that the viscosity of the coating agent at 25°C was measured within 30 minutes of preparation of the coating agent.

[0217] (2) Phase separation of coating agent

[0218] The freshly prepared coating agent was allowed to stand in a transparent container for 5 minutes. After standing, the separation state of the curing compound and hollow particles was visually observed. Phase separation of the coating agent was determined according to the following criteria. It should be noted that Comparative Examples 1-3, 5, and 6, which contain only the curing compound, are marked as "- (cannot be determined)".

[0219] [Criteria for judging phase separation of coating agents]

[0220] ○: No separation of the liquid phase and the particle phase occurred.

[0221] ×: Some of the hollow particles float to the surface, causing the liquid phase to separate from the phase containing the hollow particles (resulting in a transparent liquid layer at the bottom).

[0222] (3) Formation properties of coating layer and film

[0223] (3-1) Coating properties of the coating agent (formation properties of the coating agent layer)

[0224] Using a bar coater with a spacing set to 1.0 mm, apply 10.0 mL of coating agent to the surface of a 10 cm × 10 cm substrate. Determine the coatability of the coating agent according to the following criteria.

[0225] Criteria for judging the coatability of coating agents

[0226] ○: It will not produce fly-white or coating defects, and can coat the entire surface of the substrate with the coating agent.

[0227] ×: 1) The coating agent does not flow on the surface of the substrate and cannot be applied to the entire surface of the substrate, or 2) Skimming or coating defects occur, and there are areas on the surface of the substrate that are not coated with the coating agent.

[0228] (3-2) Formation properties of coating

[0229] A given weight of coating agent was applied evenly to a 2cm × 2cm substrate. The coating layer was then irradiated for 1 minute at an intensity of 140mW / cm². 2Ultraviolet light cures the coating layer to form a film. The more coating layers are applied in a single coat, the easier it is to form a coating layer (film) of the desired thickness. Furthermore, a film with a thickness of 200 μm was formed, and its thermal conductivity was measured using the unsteady-state fine-wire heating method. The formability of the insulating film was determined according to the following criteria.

[0230] [Criteria for judging the formability of coating]

[0231] ○: A coating layer with a thickness of 500 μm or more can be formed by applying the coating agent in a single coat, and the thermal conductivity of the coating is below 0.16 W / m·K.

[0232] ×: It is impossible to form a coating layer with a thickness of more than 500 μm through a single coating application, or the thermal conductivity of the coating exceeds 0.16 W / m·K.

[0233] (4) Remelting of solder

[0234] Based on the evaluation of the phase separation of the coating agent (2), the coating properties of the coating agent (3-1), and the film formation properties of the coating agent (3-2), the remelting of the solder is determined according to the following criteria.

[0235] Criteria for judging solder remelting

[0236] ○: All evaluations in (2), (3-1) and (3-2) are ○.

[0237] ×: At least one of the evaluations in (2), (3-1), and (3-2) is ×

[0238] The composition and results are shown in Tables 1-4 below.

[0239] [Table 1]

[0240]

[0241] [Table 2]

[0242]

[0243] [Table 3]

[0244]

[0245] [Table 4]

[0246]

[0247] Symbol Explanation

[0248] 1…electronic substrate

[0249] 2…Circuit board

[0250] 3… Soldering Department

[0251] 4…Lamination

[0252] 5… Electronic components

Claims

1. A coating agent preparation kit for use in the placement of electronic components having a coating formed by curing the coating agent in a metal mold and injection molding. The coating agent preparation kit is a coating agent preparation kit for obtaining a coating agent by mixing. The coating agent preparation kit comprises a first composition and a second composition. The first composition contains a curable compound that can be cured by ultraviolet light, heat, or moisture. The second composition contains hollow particles. The viscosity of the curable compound at 25°C is above 50 mPa·s and below 3000 mPa·s.

2. The use according to claim 1, wherein, The coating agent obtained by mixing the first composition and the second composition has a viscosity of more than 100 mPa·s and less than 30,000 mPa·s at 25°C.

3. The use according to claim 1 or 2, wherein, The curable compound includes a curable compound that can be cured by ultraviolet light and moisture.

4. Use of a coating agent in the injection molding of an electronic component having a film formed by curing the coating agent within a metal mold. The coating agent comprises: Curable compounds that can be cured by ultraviolet light, heat, or moisture, and Hollow particles, The viscosity of the curable compound at 25°C is above 50 mPa·s and below 3000 mPa·s.

5. The use according to claim 4, wherein, The viscosity of the coating agent at 25°C is between 100 mPa·s and 30,000 mPa·s.

6. The use according to claim 4 or 5, wherein, The hollow particles are either spherical particles or porous hollow particles. When the coating agent contains the balloon particles, the content of the balloon particles in 100% by weight is more than 0.5% by weight and less than 50% by weight. In the case of containing the porous hollow particles, the content of the porous hollow particles in 100% by weight of the coating agent is more than 5% by weight and less than 40% by weight.

7. The use according to claim 6, wherein, The hollow particles include spherical particles and porous hollow particles. In the coating agent, the content of the balloon particles is more than 0.5% by weight and less than 10% by weight per 100% by weight. In the coating agent, the content of porous hollow particles is more than 5% by weight and less than 40% by weight in 100% by weight.

8. The use according to claim 4 or 5, wherein, The hollow particle has a hollowness of 40% to 99% by volume.

9. The use according to claim 4 or 5, wherein, The hollow particles contain polyacrylonitrile or acrylic resin.

10. The use according to claim 4 or 5, wherein, The curable compound comprises a first curable compound that can be cured by ultraviolet light.

11. The use according to claim 10, wherein, The first curable compound can be cured by ultraviolet light, and can also be cured by heat or moisture.

12. The use according to claim 4 or 5, wherein, The curable compound includes a curable compound that can be cured by ultraviolet light and moisture.

13. The use according to claim 4 or 5, wherein, The coating agent is a coating agent for circuit boards.

14. Use of an electronic substrate in which it is disposed in a mold and injection molded, the electronic substrate comprising: Circuit board, Solder portions disposed on the surface of the circuit board, and A coating covering the solder portion. The coating is a cured product of the coating agent according to any one of claims 4 to 13.

15. The use according to claim 14, further comprising: electronic components mounted on the circuit board, The circuit board and the electronic components are electrically connected through the solder section.

16. The use according to claim 14 or 15, wherein, In the thickness direction of the coating, the hollow particles are unevenly distributed and are more present on the surface side opposite to the solder portion side.

17. The use according to claim 14 or 15, wherein, The coating has a first layer and a second layer. In the first layer (100% by weight), the content of hollow particles is less than 1.0% by weight. In the second layer (100% by weight), the content of hollow particles is 1.0% by weight or more.

18. The use according to claim 17, wherein, In the coating, the first layer is closer to the solder portion than the second layer.

19. A method for manufacturing an electronic component module, comprising: A process for preparing an electronic component on which electronic components are mounted on a circuit board, and whereby the circuit board and the electronic components are electrically connected by a conductive adhesive portion. The process of applying the coating agent according to any one of claims 4 to 13 onto the surface of the electronic component in such a way that it at least covers the conductive adhesive portion; The process of forming a coating by curing the coating agent; and The process of placing the electronic component with the coating in a metal mold for injection molding, and then sealing the electronic component with the coating with thermoplastic resin.

20. The method for manufacturing an electronic component module according to claim 19, wherein, The conductive adhesive portion is the solder portion.

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