JP5606212B2 - Colored resin composition for electrodeposition coating, water-based electrodeposition coating, coating method and coated article - Google Patents

Description

  The present invention relates to a colored resin composition for an electrodeposition coating comprising a ceramic fine particle having thermal conductivity and insulating properties, a color pigment, and a hydrophilic resin containing an acidic group or a basic group, an aqueous electrodeposition coating, The present invention relates to a painting method and a painted object. More specifically, the present invention relates to a colored resin composition for electrodeposition paint, a water-based electrodeposition paint, a coating method, and a coated article that impart color, light reflectivity, thermal conductivity, heat dissipation, and insulation to an object to be coated.

Conventionally, as a method for imparting heat dissipation to an object to be coated, a method of forming a fin shape with a large surface area by subjecting an aluminum light alloy to alumite treatment (for example, Patent Document 1), SnO ₂ —Sb ₂ O in a vehicle There is a method (for example, Patent Document 2) of applying a paint in which ₅ type semiconductor particles are used as a filler and various pigments are dispersed in a resin.

JP 2001-230580 A JP 2004-43612 A

  However, the former method is limited in the width of material selection and the space occupied by parts. The latter method is expensive because specific semiconductor particles are used, and is not applicable to complicated shapes because it is used for spray coating. Also, since semiconductor particles are blended, there is no electrical insulation and it is difficult to apply to electrical and electronic parts.

  Electrodeposition paints can be co-deposited with various resins as fillers to improve various properties depending on the application, and have extremely complex coating shapes because of their extremely uniform coating properties. However, colored electrodeposition paints that impart heat dissipation and insulation are not on the market.

  An object of the present invention is to provide a colored resin composition for an electrodeposition coating that can impart color, light reflectivity, thermal conductivity, heat dissipation, and insulation even on an intricately shaped painted surface, It is to provide a water-based electrodeposition paint, a coating method and a coated product thereof.

The present invention relates to one or more thermal conductivity and insulating properties selected from silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, beryllium oxide, magnesium oxide, zirconium oxide, boron nitride, and mixtures thereof. A resin composition comprising a ceramic fine particle, a color pigment, and a hydrophilic resin containing a basic group including an epoxyamine adduct resin , wherein the thermal conductivity and the total weight of the resin composition 5 to 40% by weight of insulating ceramic fine particles, 5 to 50% by weight of the coloring pigment, and 10 to 90% by weight of a hydrophilic resin containing a basic group including the epoxyamine adduct resin. This is a colored resin composition for electrodeposition paint that imparts thermal conductivity and heat dissipation .

  In addition, the present invention provides an electroconductive material obtained by dispersing the colored resin composition for an electrodeposition paint containing a hydrophilic resin containing a basic group in water containing an acidic neutralizing agent. It is a water-based electrodeposition paint that can be applied to a solid having a property.

  The present invention is also a method for electrodeposition coating on an electrically conductive solid using the aqueous electrodeposition coating described above.

  Further, the present invention is a coated product in which a solid having electrical conductivity is electrodeposited by the above-described electrodeposition coating method.

  Further, the present invention provides a case of a circuit board, a heating element of a dryer, a heater, a heater, and an LED (Light Emitting Diode) -related device housing to which the above-described electrodeposition coating method is applied. It is characterized by being.

According to the present invention, the epoxy amine adduct resins because it contains salt group group, may be dispersed in water containing an acid of the neutralizing agent. Also, silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, beryllium oxide, magnesium oxide, zirconium oxide, boron nitride, and one or more mixtures thereof, thermal conductivity and insulating the Ceramic fine particles (hereinafter sometimes referred to simply as “ceramic fine particles having thermal conductivity and insulation”) and coloring pigments can be dispersed in hydrophilic resins containing basic groups including epoxyamine adduct resins. By impregnating and getting wet, an aqueous electrodeposition coating material in which these are uniformly dispersed can be obtained. Ceramic fine particles with thermal conductivity and insulation after coating give thermal conductivity, heat dissipation and insulation to the object to be coated, colored pigments give various colors, and basic group containing epoxyamine adduct resin The hydrophilic resin containing can also give light reflectivity and insulation to the object to be coated after heat drying. It is possible to give color, light reflectivity, thermal conductivity, heat dissipation and electrical insulation to all solids with electrical conductivity such as metals, semiconductors, and electrically conductive ceramics that are not inherently thermally conductive. It is.

  Since the colored resin composition for electrodeposition paints of the present invention can be dispersed in water, the use amount of the organic solvent is reduced, so that it has excellent safety and environmental characteristics.

  In the present invention, an organic-inorganic hybrid coating film having a heat dissipation characteristic similar to that of anodized can be easily applied onto a metal with low heat conductivity, and the excellent uniform coating property makes it possible to freely form parts. It greatly contributes to improvement of the degree. Moreover, since it is based on an organic coating film, it also has insulating properties.

According to the present invention, since the epoxyamine adduct resin is dispersed in water containing an acidic neutralizing agent, a colored resin composition for electrodeposition coating containing ceramic fine particles having heat conductivity and insulating properties and a color pigment is added to water. Dispersed into a water-based electrodeposition paint. This aqueous electrodeposition paint can be electrodeposited on a solid having electrical conductivity, and the coated material has color, light reflectivity, thermal conductivity, heat dissipation, and electrical insulation. Moreover, since it is an aqueous electrodeposition paint, it has excellent characteristics in terms of safety and environment.

According to the present invention, the method of electrodeposition coating on a solid having electrical conductivity is such that 5 to 40% by weight of the ceramic fine particles having thermal conductivity and insulating properties are colored with respect to the total weight of the resin composition. Aqueous electrodeposition in which a colored resin composition for electrodeposition paint containing 5 to 50% by weight of a pigment and 10 to 90% by weight of a hydrophilic resin containing a basic group including the epoxyamine adduct resin is dispersed in water. Since the paint is used, it is possible to impart color, light reflectivity, thermal conductivity, heat dissipation, and electrical insulation to the coated object.

  According to the present invention, since the water-based electrodeposition paint contains ceramic fine particles and color pigments having thermal conductivity and insulation, the electrodeposited coated material has color, light reflectivity, thermal conductivity, heat dissipation. And electrical insulation.

According to the present invention, since the solid having electrical conductivity is a casing of a circuit board, a heating element of a dryer, a heater, a heater, and an LED-related device, the effect of the electrodeposition paint of the present invention can be suitably exerted. . The heat dissipating and insulating electrodeposition coating on the circuit board does not cause a chemical change of the substrate material, and can selectively and uniformly dissipate the heat dissipating insulating film only on necessary portions. Since the heat-dissipating and insulating electrodeposition coating in the heating element, the heater and the heater of the dryer increases the heat generation efficiency, the effect of power saving and CO ₂ emission suppression can be obtained. When water-based electrodeposition coating is used for the housing of LED-related equipment, it does not cause chemical changes in the substrate material, and it becomes possible to selectively dissipate heat on the necessary parts with a thin film of a few tens of microns. The design and development of the system can be given a great degree of freedom, and the characteristics of the electrodeposition paint with good paint efficiency can be utilized to contribute to the cost.

It is a flowchart of the electrodeposition coating method of one Embodiment in this invention.

(Resin composition for paint)
In the present invention, one or two or more selected from silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, beryllium oxide, magnesium oxide, zirconium oxide, boron nitride, and mixtures thereof are thermally conductive and insulating. The ceramic fine particles having the term “solid fine particles” refer to fine solid particles having hardness, nonflammability, and non-corrosiveness, and thermal conductivity and insulation. By blending these in the electrodeposition coating, it is possible to impart thermal conductivity, heat dissipation and insulation to the coating film.

  The ceramic fine particles are one or more selected from silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, beryllium oxide, magnesium oxide, zirconium oxide, boron nitride, and mixtures thereof, but are particularly realistic. In consideration of applicability, aluminum oxide, magnesium oxide, zirconium oxide and boron nitride are preferred from the viewpoints of being available at a relatively low cost, high thermal conductivity, chemically stable and harmless.

  The thermal conductivity of the ceramic fine particles is usually 1 to 2,000 W / m · K, preferably 5 to 1,000 W / m · K, and particularly preferably 10 to 500 W / m · K. When it is 1 to 2,000 W / m · K, heat conductivity and heat dissipation can be exhibited, and when it is 5 to 1,000 W / m · K, heat conductivity and heat dissipation are further improved, and 10 to 500 W / m When m · K, the thermal conductivity and heat dissipation are particularly good.

  The ceramic fine particles may be in various shapes such as spherical, fibrous, flaky, fibrous, and needle-like, and even after using the crystalline form of the substance itself, it is commercially available after being crushed and classified. Grades may be used. Among these, the spherical shape is preferable from the viewpoint of dispersibility.

  From the viewpoint of increasing the heat transfer efficiency between the coating film and the atmospheric gas, it is preferable to use a particulate material as the above-mentioned ceramic fine particles having thermal conductivity and insulating properties. When ceramic fine particles are blended, the smoothness of the surface shape is disturbed to some extent, and the surface area is increased. That is, the heat exchange area is expanded, and at this time, a turbulent flow is further generated on the surface of the coating film, so that the heat exchange efficiency can be improved. If the particle size is too small, the dispersibility is high and the surface of the coating film becomes smooth, and the heat exchange efficiency may not be sufficiently improved. For this reason, the particle diameter of the ceramic fine particles is preferably 5 nm or more, more preferably 10 nm or more, and particularly preferably 20 nm or more. On the other hand, if it is too large, the smoothness is disturbed and the gloss is lowered, and the particles may be detached after the coating film is formed. For this reason, the particle diameter of the ceramic fine particles is preferably 20 μm or less, more preferably 10 μm or less, and particularly preferably 8 μm or less. In the present invention, the particle diameter means the average diameter of the ceramic fine particles used, and can be measured by an ultracentrifugal automatic particle size distribution analyzer (for example, CAPA-700 manufactured by Horiba, Ltd.).

  The color pigments used in the present invention can be those widely used for electrodeposition paints, for example, white pigments such as zinc white, lithopone, titanium dioxide, precipitated barium sulfate; iron oxide red, anthraquinone, quinacridone Red pigments such as diketo-pyrrolo-pyrrole, perylene, indigoid; yellow pigments such as isoindolinone, isoindoline, quinophthalone, pyrazolone, flavatron, anthraquinone; ultramarine blue, prussian blue (potassium ferrocyanide), ultramarine blue, Blue pigments such as phthalocyanine, anthraquinone, indigoid, and carbonium; black pigments such as carbon black, carbon nanotube, and graphite; and green pigments such as phthalocyanine, perylene, nitroso, and carbonium, and one or more of these of Compounds can be used. Further, the ceramic fine particles used in the present invention are not included in the color pigment. The color pigment imparts improvements in color tone characteristics and light reflectance among the characteristics of the aqueous electrodeposition coating.

The hydrophilic resin constituting the resin composition for electrodeposition paints of the present invention is a hydrophilic resin containing a basic group containing an epoxyamine adduct resin. In the following description, a hydrophilic resin containing an acidic group and Of the hydrophilic resins described as hydrophilic resins containing basic groups, hydrophilic resins that do not contain an epoxyamine adduct resin are outside the scope of the present invention. A hydrophilic resin containing an acidic group or a hydrophilic resin containing a basic group is a resin containing an acidic group or a basic group, and is neutralized with a basic neutralizing agent or an acidic neutralizing agent. There is no limitation as long as a coating material can be formed. Examples of the acidic group of the hydrophilic resin containing an acidic group include a carboxyl group, a sulfonic acid group, a phosphoric acid group, and a phosphonic acid group, and a carboxyl group is preferable for electrodeposition coatings. Examples of the basic group of the hydrophilic resin containing a basic group include an amino group, an amide group, a pyridine group, a pyrrolidone group, an imidazole group, and an imine group, but an amino group is preferable for electrodeposition coatings.

  Examples of hydrophilic resins containing acidic groups or hydrophilic resins containing basic groups include acrylic resins, epoxy resins, styrene resins, olefin resins, vinyl ester resins, polyester resins, polyamide resins, Examples include polyurethane resins, poly (thio) ether resins, polycarbonate resins, polysulfone resins, polyimide resins, resins in which acidic groups or basic groups are introduced into cellulose ester resins, acrylic resins, epoxy resins A resin containing an acidic group or a basic group is easy to use as a preferred electrodeposition paint.

  As such a thing, the acrylic copolymer which has an acidic group or a basic group, and an epoxyamine adduct resin are preferable.

  The acrylic copolymer is obtained by copolymerizing a monomer having an acidic group or a basic group with another polymerizable monomer.

  The acrylic copolymer having an acidic group is obtained, for example, by copolymerizing a carboxyl group-containing monomer (a), a hydroxyl group-containing monomer (b), and another monofunctional monomer (c). It is done.

  As the carboxyl group-containing monomer (a), known monomers can be used, for example, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, etc. Examples include compounds having a bond. Among these, acrylic acid and methacrylic acid are preferable. A carboxyl group-containing monomer can be used individually by 1 type, or can use 2 or more types together.

  A well-known thing can be used as a hydroxyl-group containing monomer (b), For example, (meth) acrylic-acid alkyl group alkyl, for example, (meth) acrylic-acid 2-hydroxyethyl, (meth) acrylic-acid 2-hydroxypropyl, ( And (meth) acrylic acid 3-hydroxypropyl, (meth) acrylic acid 4-hydroxybutyl, caprolactone-modified (meth) acrylic acid hydroxy ester, and the like. Caprolactone-modified (meth) acrylic acid hydroxy ester is obtained by adding (meth) acrylic acid to caprolactone, and a commercially available product can be used. Examples of commercially available products in which (meth) acrylic acid is added to caprolactone include Plaxel FM1, Plaxel FM2, Plaxel FM3, Plaxel FA1, Plaxel FA2, Plaxel FA3 (registered trademark, manufactured by Daicel Chemical Industries). A hydroxy group containing monomer can be used individually by 1 type, or can use 2 or more types together. Of these, (meth) acrylic acid ester 2-hydroxyethyl is preferred. The hydroxy group-containing monomer is nonionic but can impart hydrophilicity to the copolymer. Here, (meth) acrylic acid ester means both acrylic acid ester and methacrylic acid ester.

  Other monofunctional monomers (c) are not particularly limited. For example, methyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (meth) acrylic acid 2 -(Meth) acrylic acid ester having an alkyl group having 1 to 18 carbon atoms such as ethylhexyl; aralkyl group-containing (meth) acrylic acid ester such as benzyl (meth) acrylate; cyclohexyl (meth) acrylate, isobornyl acrylate, Cyclic alkyl (meth) acrylic acid esters such as 2-acryloyloxyethyl hydrogen phthalate and 2-acryloyloxypropyl hydrogen phthalate; fluorinated alkyl (meth) such as 2- (perfluorooctyl) ethyl methacrylate and trifluoromethyl methacrylate Acrylic acid ester; vinyl acetate Le; N- phenylmaleimide, etc. N- cyclohexyl maleimide. These 1 type (s) or 2 or more types can be used together.

  In addition, the acrylic copolymer having a basic group includes, for example, an amino derivative (d) of (meth) acrylic acid, a hydroxyl group-containing monomer (b), and another monofunctional monomer (c). Obtained by polymerization.

  As the amino derivative (d) of (meth) acrylic acid, amino derivatives such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and ethyltrimethylammonium acrylate chloride can be used.

  As the hydroxyl group-containing monomer (b) and other monofunctional monomers (c), those described above can be used.

  About the compounding quantity of the monomer in an acrylic copolymer, the combination of said monomer (a), (b), (c) or (d), (b), (c) is performed by arbitrary ratios. be able to. Examples of the monomer content include 5 to 30% by weight of the carboxyl group-containing monomer (a) or (meth) acrylic acid amino derivative (d), and 5% of the hydroxy group-containing monomer (b). Those containing ˜30% by weight and 40 to 90% by weight of the other monofunctional monomer (c) are preferred. As the polymerization conditions, normal acrylic polymerization conditions can be preferably applied. In this case, it may be carried out in a known water-soluble organic solvent. For example, 40 to 80% by weight of the water-soluble organic solvent is used.

  The weight average molecular weight of the acrylic copolymer containing an acidic group or a basic group obtained by polymerization is preferably 1,000 to 40,000, particularly preferably 2,000 to 30,000. When the weight average molecular weight is 1,000 or more, the dispersibility in water is good, and precipitation of the electrodeposition coating itself is difficult to occur. When it is 40,000 or less, a defective appearance of coating such as yuzu skin does not occur and a uniform appearance can be obtained. In addition, the weight average molecular weight Mw of this acrylic copolymer can be measured by a gel permeation (GPC) method, for example, can be measured as follows.

  In a GPC apparatus (trade name: HLC-8220 GPC, manufactured by Tosoh Corporation), measurement is performed by injecting 100 ml of a sample solution using a column set at a temperature of 40 ° C. As a sample solution, a solution obtained by dissolving a 0.25% tetrahydrofuran solution of an acrylic copolymer (dry product) overnight is used. The molecular weight calibration curve is prepared using standard polystyrene (monodisperse polystyrene).

  Further, as the epoxyamine adduct resin, a derivative obtained by modifying the epoxy group of the epoxy resin with primary and secondary amines by 30 to 100% can be preferably used. For the reaction, those dissolved in 40 to 80% by weight of an aqueous organic solvent can be used.

  As epoxy resins, bisphenol A type epoxy resins [trade names: Epicoat 828, Epicoat 834, Epicoat 1001, Epicoat 1004, Epicoat 1007, Epicoat 1009 (above, manufactured by Japan Epoxy Resin Co., Ltd.)], novolak phenol type epoxy resin [trade name : Epicoat 152, Epicoat 154 (manufactured by Japan Epoxy Resin Co., Ltd.)], glycidylamine type epoxy resin [Product Name: Epicoat 604 (Japan Epoxy Resin)], and dimer acid type epoxy resin (Product Name: Epicoat 872 (Japan Epoxy resin)]] can be used, but is not limited thereto.

Examples of the primary amine include monoalkanolamines having 1 to 4 carbon atoms such as monomethanolamine, monoethanolamine and monoisopropanolamine; monoalkylamines having 1 to 4 carbon atoms such as dimethylaminoethylamine, diethylaminoethylamine and diethylaminopropylamine. Secondary amines include dialkanolamines having 1 to 4 carbon atoms such as dimethanolamine, diethanolamine and diisopropanolamine; monoalkanols having 1 to 4 carbon atoms such as methylethanolamine and methylpropanolamine. Amine: Although a C1-C4 dialkylamine, such as diethylamine and di n-butylamine, can be used, it is not limited to these. The above alkanolamine is preferably used because it improves the hydrophilicity of the adduct.

  Primary and secondary amines can be added in response to epoxy groups. It is preferable to use 0.5 to 1.2 equivalents of primary or secondary amine H to 1 equivalent of epoxy group. The reaction is preferably performed at room temperature to 50 ° C. In this way, an epoxyamine adduct resin with an amino group added is obtained.

  The resin composition for coatings of the present invention comprises 5 to 40% by weight of ceramic fine particles having thermal conductivity and insulating properties, 5 to 50% by weight of the color pigment, and the acidity based on the total weight of the resin composition. 10 to 90% by weight of a hydrophilic resin containing a group or a hydrophilic resin containing a basic group is blended.

  When the composition ratio of the ceramic fine particles is less than 5% by weight with respect to the resin composition for electrodeposition paints, sufficient thermal conductivity, heat dissipation and insulation cannot be obtained for the object to be coated, and exceeds 40% by weight. The resin composition is difficult to disperse or dissolve in water. Preferably it is 5-30 weight%, Most preferably, it is 10-25 weight%. If the color pigment is less than 5% by weight based on the resin composition for electrodeposition paints, sufficient color tone cannot be obtained, and if it exceeds 50% by weight, the resin in which the color pigment is dispersed is difficult to disperse or dissolve in water. . Preferably it is 10 to 50% by weight. When the hydrophilic resin containing an acidic group or the hydrophilic resin containing a basic group is less than 10% by weight based on the resin composition for electrodeposition coatings, a resin containing ceramic fine particles is dispersed or dissolved in water. Hard to do. If it exceeds 90% by weight, the eutectoid rate of the ceramic fine particles is lowered, sufficient heat dissipation cannot be obtained, and the thermal conductivity and insulation properties are also poor. Preferably it is 20 to 85 weight%, Most preferably, it is 25 to 80 weight%.

  In addition, in order to express the insulating properties of the resin composition for electrodeposition paints and the general properties of the coating film, melamine resins such as methylated melamine resin, butylated melamine resin, and benzoguanamine resin; tolylene diisocyanate, diphenylmethane Diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and the like may be trimerized and blocked with methyl ethyl ketoxime, ε-caprolactam, phenol, diketone, etc .; a polyimide resin or the like may be mixed with the above resin. These resins can react and crosslink with functional groups such as hydroxyl groups and carboxyl groups of hydrophilic resins containing acidic groups or hydrophilic resins containing basic groups to enhance the performance of the resins.

  As the polyimide resin, a solvent-soluble imide resin in which the following (e) and (f) are reacted in an equimolar amount in an appropriate organic solvent, followed by dehydration ring-closing reaction to complete imidization can be used.

(E) Aromatic tetracarboxylic dianhydride 3,4,3 ′, 4′-benzosulfone tetracarboxylic dianhydride, 3,4,3 ′, 4′-diphenyltetracarboxylic dianhydride, bis -(3,4-dicarboxyphenyl) ether dianhydride, 2,2-bis- (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, etc.

(F) Aromatic diamine 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 1,3-bis- (4-aminophenoxy) -benzene, 2,2 ′-[4- (4- Aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] 1,1,1,3,3,3-hexafluoropropane, bis [4- (3-aminophenoxy) phenyl Sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, and the like.
Moreover, N, N'-m-xylene bismaleimide, N, N'-4,4'-diphenylmethane bismaleimide, N, N'-m-phenylene bismaleimide, N, N'-4,4'-diphenyl ether bis Thermally crosslinkable imide compounds such as maleimide, N, N′-m-xylenebisnadiimide, and N, N′-4,4′-diphenylmethanebisallylnadiimide can also be used.

  These cross-linked resins can be applied to both acrylic copolymers and epoxyamine adduct resins, but acrylic copolymers can exhibit the characteristics of resins when used with melamine resins and epoxyamine adduct resins with polyimide resins. preferable. The blending amount of these melamine resins and polyimide resins is preferably 15 to 60% by weight, more preferably 20 to 50% by weight, based on the total amount of the resin.

(Water-based electrodeposition paint)
The aqueous electrodeposition coating composition of the present invention contains the colored resin composition for electrodeposition coating composition of the present invention, an acidic or basic neutralizing agent (hereinafter sometimes simply referred to as neutralizing agent) and water. The aqueous electrodeposition coating composition of the present invention may be produced by adding a neutralizing agent to the colored resin composition for electrodeposition coating composition of the present invention and mixing the mixture, then throwing it into water and dispersing it. After dissolving in water, the resin composition for electrodeposition paints of the present invention may be added and dispersed to produce. The former is preferred. The content of the resin composition for electrodeposition paints in the aqueous electrodeposition paint is preferably 5 to 20% by weight, more preferably 8 to 15% by weight, based on the total amount of the aqueous electrodeposition paint, as a solid content (coating film forming component). is there. When the content is 5% by weight or more and 20% by weight or less, the dispersion state of each component in the paint becomes stable, no aggregation / precipitation occurs, and a uniform coating film appearance is obtained.

  A hydrophilic resin containing an acidic group or a hydrophilic resin containing a basic group is obtained by dispersing ceramic fine particles having thermal conductivity and insulating properties in water and then applying thermal conductivity and insulating properties to an object by electrodeposition coating. To deposit ceramic fine particles.

  Examples of acidic neutralizing agents for dispersing hydrophilic resins containing basic groups in water include organic acids such as lactic acid, acetic acid, formic acid, succinic acid, butyric acid, and methanesulfonic acid, and inorganic acids such as hydrochloric acid and nitric acid. Can be used. Preference is given to organic acids.

  Basic neutralizing agents for dispersing hydrophilic resins containing acidic groups in water include amine neutralizing agents such as dimethylamine, trimethylamine, diethylamine, triethylamine, morpholine, pyridine; sodium carbonate, potassium carbonate, An inorganic neutralizing agent such as sodium hydroxide or potassium hydroxide can be used. Preference is given to amine-based neutralizing agents.

  The amount of these acidic neutralizers and basic neutralizers can be arbitrarily changed according to the content of acidic groups or basic groups of the hydrophilic resin, the solubility of the resin in water, and the like. However, it is preferably 0.2 to 8 g, more preferably 0.5 to 7 g, and particularly preferably 1 to 6 g with respect to 1 liter of the finished electrodeposition coating material. When the content is 0.2% by weight or more, each hydrophilic resin is sufficiently water-soluble, and each hydrophilic resin is uniformly dispersed in water. If it is 5% by weight or less, the neutralizing agent hardly remains as an impurity, and there is no possibility of adversely affecting the cured coating film by heating after electrodeposition coating.

  The water-based electrodeposition paint mixed as described above can be dispersed in water with impregnation and wettability between the hydrophilic resin and the ceramic fine particles having thermal conductivity and insulation, and can be electrodeposited. Further, due to the characteristics of the composition, the use amount of the organic solvent is reduced, so that it has excellent characteristics in terms of safety and environment.

(Electrodeposition coating)
Electrodeposition coating using the aqueous electrodeposition paint of the present invention can be carried out in the same manner as conventional electrodeposition coating. For example, after subjecting the target base material to be coated to a degreasing treatment and pickling treatment as necessary, the target base material is immersed in the aqueous electrodeposition coating material of the present invention and energized. An uncured electrodeposition coating is formed on the surface of the material. By heating the object to be coated on which the uncured electrodeposition coating film is formed, a cured electrodeposition coating film is formed on the surface of the object to be coated.

The flowchart of the electrodeposition coating method of one embodiment in the present invention is shown in FIG.
First, weak alkali degreasing is performed in step S1. For example, it is performed by supplying an alkaline aqueous solution to the surface of the target substrate. The supply of the alkaline aqueous solution is performed, for example, by spraying the alkaline aqueous solution on the target base material or immersing the target base material in the alkaline aqueous solution. As the alkali, those commonly used for metal degreasing can be used, and examples include alkali metal phosphates such as sodium phosphate and potassium phosphate. The alkali concentration in the aqueous alkali solution is appropriately determined according to, for example, the type of metal to be treated and the degree of contamination. Furthermore, the alkaline aqueous solution may contain an appropriate amount of a surfactant such as an anionic surfactant and a nonionic surfactant. Degreasing is performed at a temperature of about 20 to 50 ° C. (liquid temperature of the alkaline aqueous solution) and is completed in about 1 to 5 minutes. In addition, degreasing to be immersed in an acidic bath, bubbling immersion degreasing, electrolytic degreasing, and the like can be appropriately combined.

In step S2, the target substrate is washed with water.
In step S3, neutralization (pickling treatment) is performed with a prize having a concentration of 1%. The pickling treatment is performed, for example, by supplying an acid aqueous solution to the surface of the target substrate. The supply of the acid aqueous solution is performed by spraying the acid aqueous solution onto the target substrate, immersing in the acid aqueous solution, or the like, similarly to the supply of the alkaline aqueous solution in the degreasing treatment. As the acid, those commonly used for metal pickling can be used, and examples thereof include sulfuric acid, nitric acid, and phosphoric acid. The acid concentration in the acid aqueous solution is appropriately determined according to, for example, the type of metal to be treated. The pickling treatment is performed at a temperature of about 20 to 30 ° C. (liquid temperature of the acid aqueous solution) and is completed in about 15 to 60 seconds. In addition to the degreasing treatment and pickling treatment, scale removal treatment, ground treatment, rust prevention treatment, and the like may be performed.

In step S4, the target substrate is washed with water.
In step S5, ion-exchange water washing is further performed.

  In step S6, electrodeposition coating is performed. The electrodeposition coating is carried out in accordance with a known method, for example, by immersing the target substrate completely or partially in an energization tank filled with the aqueous electrodeposition paint of the present invention to form an anode and energizing. There are no particular restrictions on the electrodeposition coating conditions, and there are various conditions such as the type of solid that has electrical conductivity as the target substrate, the type of electrodeposition paint, the size and shape of the current-carrying tank, and the intended use of the object to be coated. Depending on the range, the temperature can be appropriately selected. Usually, the bath temperature (electrodeposition paint temperature) is about 10 to 50 ° C., the applied voltage is about 10 to 450 V, the voltage application time is about 1 to 10 minutes, the liquid temperature of the aqueous electrodeposition paint. What is necessary is just to be 10-45 degreeC.

  Wash with water in step S7 and dry in step S8. The object to be coated with the electrodeposition coating is taken out from the energizing tank, washed with water and dried.

Baking is performed in step S9.
Baking includes pre-drying and curing heating. Curing heating is performed after preliminary drying. The preliminary drying is performed under heating at about 60 to 140 ° C. and is completed in about 3 to 30 minutes. Curing heating is performed under heating at about 150 to 220 ° C. and is completed in about 10 to 60 minutes. Thus, the electrodeposition coating film by the aqueous electrodeposition coating material of this invention is obtained.

  The target substrate in the present invention is applicable not only to metals but also to all solids having electrical conductivity such as semiconductors such as silicon and indium titanate, and electrically conductive ceramics. In other words, the target substrate is not limited as long as it can be electrodeposition-coated, but it can also be applied to stainless steel (SUS304), aluminum or anodized aluminum material, plating material or plated article, die casting, and the like.

  Any material commonly used in this field can be used as the plating material, such as pure iron, carbon steel, high tensile strength steel (low alloy steel, maraging steel), magnetic steel, nonmagnetic steel, high manganese steel, Stainless steel (martensitic stainless steel, ferritic stainless steel, austenitic stainless steel, austenitic / ferritic stainless steel, precipitation hardened stainless steel, etc.), iron-based metals such as superalloy steel, copper and copper alloys (oxygen-free copper, phosphor bronze, Tough pitch copper, aluminum bronze, beryllium copper, high-strength brass, red brass, western white, brass, free-cutting brass, Nevlar brass, etc.), iron / nickel alloy, nickel / chromium alloy, nickel, chromium, aluminum and aluminum alloy, magnesium And magnesium alloys, titanium, zirconium, hafnium and their alloys, Buden, tungsten and alloys thereof, niobium, tantalum and alloys thereof, ceramics such (alumina, etc. Jirukoa) and the like. The type of plating applied to the surface of the plating material is not particularly limited, and any plating commonly used in this field can be adopted. For example, copper / nickel / chrome plating, nickel / boron / tungsten plating, nickel / boron plating, brass plating, bronze plating and other alloy plating, gold plating, silver plating, copper plating, tin plating, rhodium plating, palladium plating, Examples include platinum plating, cadmium plating, nickel plating, chromium plating, black chrome plating, zinc plating, black nickel plating, black rhodium plating, zinc plating, and industrial (hard) chromium plating. Examples of the die casting include zinc die casting, aluminum die casting, magnesium die casting, and sintered alloy die casting.

(Painted material)
The above-mentioned water-based electrodeposition paint is coated with a coating containing ceramic fine particles having thermal conductivity and insulating properties, so that a solid, electrically conductive, color, light reflective, thermal Improvements in conductivity, insulation, heat dissipation, and thermal conductivity can be realized.
Accordingly, the aqueous electrodeposition coating composition of the present invention is particularly suitably used for the following applications.

(1) Heat dissipation applications related to boards In automobile transmission parts, personal computers and peripheral devices, game machines, and mobile phones, malfunctions occur due to heat generation due to high-speed LSI high-density wiring CPUs and reduction in heat dissipation space due to downsizing. Faced with problems such as the occurrence of lifespan, reduced life. By using the water-based electrodeposition paint of the present invention, such problems can be solved by imparting heat dissipation.

(2) Heat countermeasure applications such as dryer heating elements, heaters, heaters, etc. In order to increase the heat generation efficiency of these products, by applying the aqueous electrodeposition paint of the present invention to the necessary places, power saving and The effect of suppressing CO ₂ emission is obtained.

(3) Heat radiation reflection application in the case of LED-related equipment Television picture machines and LED lighting fixtures with LED backlight gloss, the case part generates heat due to LED light-emitting elements, substrate circuits, insulated gate bipolar transistors, etc. . The water-based electrodeposition paint of the present invention can be used to release heat at that portion and at the same time amplify the brightness during light emission.

  When the water-based electrodeposition coating of the present invention is used for such parts, it is possible to perform heat insulation insulation coating with selective and uniform thin film of several tens of microns only on necessary parts without causing chemical change of the substrate material. Therefore, it gives a great degree of freedom to the development and design of the substrate, and can also contribute to the cost by taking advantage of the characteristics of the electrodeposition paint with good painting efficiency.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
(A-1) and (A-2) as ceramic fine particles having thermal conductivity, (B-1) and (B-2) as color pigments, and (C-1) and (C-2) as hydrophilic resins. ) Were used.
(A-1): Silicon oxide (A-2): Boron nitride (B-1): Precipitated barium sulfate (B-2): Graphite

[Synthesis of hydrophilic resin (C-1)]
A 4-necked flask equipped with a Dimroth reflux tube was charged with 43 g of diethylene glycol monoisopropyl ether and heated to reflux. Next, 5 g of acrylic acid, 20 g of methyl methacrylate, 30 g of 2-hydroxyethyl acrylate, 20 g of n-butyl acrylate, 25 g of styrene and 1 g of benzoin peroxide as a polymerization initiator were added and mixed uniformly. Moved to. A dropping funnel is attached to the four-necked flask, and the mixture is stirred with a motor to divide the monomer mixture into 8 portions and dropped at intervals of 10 minutes. The reaction was carried out at a reaction temperature of 70-80 ° C. for 5-6 hours. Thereafter, 0.1 g of benzoin peroxide was added, and the mixture was refluxed for about 1 hour until the monomer odor disappeared. The solid content was 70%, the viscosity was 20,000 mPa · s (25 ° C.), and the acid value was 35. A clear resin solution was obtained.

  Moreover, what mixed 100 weight part of said resin solutions and 30 weight part of benzoguanamine was made into hydrophilic resin (C-1).

[Synthesis of hydrophilic resin (C-2)]
In a four-necked flask equipped with a Dimroth reflux tube, 500 g of Epicoat 1001 (epoxy resin, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent: 474) and 300 g of propylene glycol monomethyl ether were mixed and dissolved. The liquid temperature was raised to 90 ° C. and maintained, and 180 g of diethanolamine was transferred to the dropping funnel. A dropping funnel was attached to the four-necked flask and stirred with a motor, and the amine was added dropwise in 60 minutes. After completion of the dropwise addition, the mixture was heated at 120 ° C. for 90 minutes to obtain a yellow transparent epoxy amine adduct resin solution having a solid content concentration of 70%, a viscosity of 13,000 mPa · s (25 ° C.), and a EQ of 180.

  Further, 100 parts by weight of the epoxyamine adduct resin solution and 30 parts by weight of hexamethylene diisocyanate trimer blocked with methylethylketoxime were used as a hydrophilic resin (C-2).

(Examples 1 and 2, Reference Examples 1 to 4 and Comparative Examples 1 and 2)
(1) Preparation of paint For Examples 1 and 2 and Reference Examples 1 to 4 , the hydrophilic resin obtained above, ceramic fine particles having thermal conductivity and insulating properties, and coloring pigments were mixed in appropriate amounts, respectively, and a neutralizing agent. And dispersed in water. Table 1 shows the resin amount, neutralizing agent amount, and stirring conditions for each example. Table 1 also shows the pH and electrical conductivity of the prepared aqueous electrodeposition coating. In addition, the numerical value in Table 1 is the gram number contained in 1 liter of water-based electrodeposition coating materials.

As can be seen from Table 1 below, the solvent concentration in the paints of Examples 1 and 2 and Reference Examples 1 to 4 is as low as 1.5%, which is highly safe and has little influence on the environment.

(2) Electrodeposition coating experiment Next, electrodeposition coating was performed on the test piece.

The aqueous electrodeposition paints of Examples 1 and 2, Reference Examples 1 to 4 and Comparative Examples 1 and 2 are placed in a 1 liter tank, and the liquid temperature is maintained at 25 ° C. Electrodeposition coating was performed using a carbon plate for the anode and a SUS304 plate (50 × 50 mm) as a test piece for the cathode. Specific conditions are shown according to FIG.

  First, in step S1, the SUS304 plate was subjected to weak alkali degreasing at 50 ° C. for 5 minutes, and washed in step S2. In step S3, neutralization was performed at room temperature for 1 minute using nitric acid having a concentration of 1%, and the mixture was washed with water in step S4. In step S5, ion-exchange water washing was performed, and in step S6, electrodeposition coating was performed at a voltage of 100 V for 1 minute. After washing with water at step S7 and drying at step S8 (15 minutes at 100 ° C.), finally, baking at 180 ° C. for 30 minutes was performed at step S9.

  As general evaluation items of the coating film, film thickness (JIS K5600), appearance (visual observation), cross-cut peel test (JIS K5600), volume resistance value, and dielectric breakdown voltage were measured. Table 1 shows the formulation and general evaluation results of the coating film.

  As the heat radiation characteristics and the light reflectance, the following were measured at a film thickness of 15 μm. For comparison, anodized plates were measured simultaneously.

For the heat dissipation characteristics, the sample was heated, and the difference between the heat source temperature and the sample temperature was measured with a thermograph.
The light reflectivity was measured with a spectrophotometer at a wavelength of 460 nm.
The results are shown in Table 2.

Regarding the film thickness, the paints of Examples 1 and 2, Reference Examples 1 to 4 and Comparative Examples 1 and 2 were 9 to 15 μm, and a smooth appearance was obtained in all cases.

The cross-cut peel test was 100/100 for Examples 1 and 2, Reference Examples 1 to 4 and Comparative Examples 1 and 2 and was good.
In the breakdown voltage, good values were shown in all examples and comparative examples.

Regarding the difference between the heat source temperature and the sample temperature, in Examples 1 and 2, Reference Examples 1 to 4 and Comparative Example 1, the thermal conductivity equivalent to that of the alumite plate was shown.

As a result of the light reflectance measurement, Examples 1 and 2, Reference Examples 1 to 4 and Comparative Example 2 showed a high reflectance of 90% or more.

  As described above, the water-based electrodeposition paint of the present invention uses a combination of ceramic fine particles and a color pigment, so that the color, light reflectivity, heat conductivity, It is possible to provide heat dissipation and provide electrical insulation. It also has excellent characteristics in terms of safety and environment.

Claims (5)

Ceramic fine particles having thermal conductivity and insulating properties, one or more selected from silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, beryllium oxide, magnesium oxide, zirconium oxide, boron nitride, and mixtures thereof And a resin composition comprising a coloring pigment and a hydrophilic resin containing a basic group including an epoxyamine adduct resin , the resin composition having the thermal conductivity and insulation properties with respect to the total weight of the resin composition Thermal conductivity comprising 5 to 40% by weight of ceramic fine particles, 5 to 50% by weight of the color pigment, and 10 to 90% by weight of a hydrophilic resin containing a basic group including the epoxyamine adduct resin . And a colored resin composition for electrodeposition paint that imparts heat dissipation . An aqueous electrodeposition paint capable of being applied to a solid having electrical conductivity, wherein the resin composition for an electrodeposition paint according to claim 1 is dispersed in water containing an acidic neutralizing agent. A method for electrodeposition-coating a solid having electrical conductivity using the aqueous electrodeposition paint according to claim 2 . A coated product obtained by electrodeposition coating a solid having electrical conductivity by the electrodeposition coating method according to claim 3 . The coated object according to claim 4, wherein the electrically conductive solid is a casing of a circuit board, a heating element of a dryer, a heater, a heater, or an LED-related device.

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