Cationic electrodeposition coating composition and electronic components having the coating film

Abstract

To provide a cationic electrodeposition coating composition that achieves excellent insulation and edge covering performance suitable for electronic components, and an electronic component having a coating film coated with the cationic electrodeposition coating composition.SOLUTION: The foregoing problem is solved by a cationic electrodeposition coating composition comprising a cationic epoxy resin (A), an organic acid zinc compound (B), and a phenolic compound (C).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a cationic electrodeposition coating composition and an electronic component having a coating film. [Background technology]

[0002] In electronic components, insulating properties have traditionally been provided through painting to prevent electrical conductivity. In recent years, however, other functions are increasingly being demanded of coatings and other paint finishes. For example, electronic components used in automobiles are required to maintain their insulating properties and other performance characteristics for extended periods even in high-temperature environments (high-temperature durability). Patent Document 1 discloses an electronic component that satisfies the requirement of high-temperature durability by containing a specific amino group-modified epoxy resin in its coating. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-154458 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In recent years, there has been a growing demand for higher performance in electronic components, requiring a high level of reliability in insulation. To ensure high reliability in insulation, it is important to coat not only the flat surfaces of electronic components but also the edges (end faces and sharp corners) without defects, and for this purpose, a coating with excellent edge covering properties is necessary. Therefore, the present invention aims to provide a cationic electrodeposition coating composition with excellent insulation and edge covering properties applicable to electronic components, and an electronic component having a coating film coated with the above cationic electrodeposition coating composition. [Means for solving the problem]

[0005] The present invention, which achieves the above objectives, may include the following: [1] A cationic electrodeposition coating composition comprising a cationic epoxy resin (A), an organic acid zinc compound (B), and a phenol compound (C). [2] The cationic electrodeposition coating composition according to [1], wherein the organic acid zinc compound (B) is contained in an amount of 10 ppm or more and 1000 ppm or less on the basis of divalent zinc ions. [3] The cationic electrodeposition coating composition according to [1] or [2], wherein the phenol compound (C) is contained in an amount of 1 to 20 parts by mass per 100 parts by mass of the cationic epoxy resin (A). [4] The cationic electrodeposition coating composition according to any one of [1] to [3], wherein the phenol compound (C) comprises phenols and / or phenolic resins, formaldehyde, and Mannich reaction products of amines. [5] The Mannich reaction products of phenols and / or phenolic resins, formaldehyde, and amines include those cationized with organic acids. The aforementioned amines include at least one selected from N-methylethanolamine and diethanolamine. The aforementioned organic acid comprises a monovalent organic acid, as described in [4], the cationic electrodeposition coating composition. [6] The cationic epoxy resin is obtained by reacting an epoxy resin (A1) with an amine compound (A2) to obtain an amino group modified epoxy resin, which is then cationized with an organic acid. The epoxy resin (A1) is The constituent elements derived from the propylene oxide-added diepoxy resin (a1) represented by formula (1) rank and, A constituent unit derived from the bisphenol compound (a2), A constituent unit derived from a different diepoxy resin (a3) ​​than formula (1), A constituent unit derived from a dicarboxylic acid (a4) in which two carboxyl groups are bonded via at least one carbon atom, A cationic electrodeposition coating composition according to any one of [1] to [5], wherein the resin has the following properties. [ka] [In formula (1), R 1 [wherein -Rb-Rc- is a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, and C3-Rb-Rc- is a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, and C3-Rb-Rc- is a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, or a C3-Rb-Rc- [7] The cationic electrodeposition coating composition according to any one of [1] to [6], further comprising a blocked polyisocyanate curing agent (D). An electronic component having a coating film painted with any of the cationic electrodeposition coating compositions described in [8][1] to [7]. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a cationic electrodeposition coating composition that is applicable to electronic components and has excellent edge covering properties and insulating properties, and an electronic component having a coating film painted with the cationic electrodeposition coating composition. [Modes for carrying out the invention]

[0007] The present invention will be described in detail below with reference to specific embodiments. <Cationic electrodeposition coating composition> A cationic electrodeposition coating composition according to one embodiment of the present invention comprises a cationic epoxy resin (A), an organic acid zinc compound (B), and a phenol compound (C).

[0008] <Cationic epoxy resin (A)> The cationic epoxy resin (A) is not particularly limited as long as it is a cationized epoxy resin. For example, an aminogroup-modified epoxy resin obtained by reacting an epoxy resin (A1) with an amine compound (A2) and cationized with an organic acid can be used. As the above epoxy resin (A1), bisphenol-type and novolak-type epoxy resins are particularly suitable, and among the bisphenol-type epoxy resins, the modified epoxy resin shown below is more suitable.

[0009] <Modified epoxy resin> The modified epoxy resin has, for example, a structural unit derived from a propionoxide-added diepoxy resin (a1) represented by the formula (1), a structural unit derived from a bisphenol compound (a2), a structural unit derived from a diepoxy resin (a3) different from the formula (1) and a structural unit derived from a dicarboxylic acid (a4)p in which two carboxyl groups are bonded via at least one carbon atom. It is preferably had. [Chemical formula] [In the formula (1), R 1 is an alkylene group having 3 to 10 carbon atoms which may have a substituent, a cyclohexylene group which may have a substituent, a phenylene group which may have a substituent, or -Ra-Rb-Rc-, Ra and Rc are cyclohexylene groups or phenylene groups, Rb is a methylene group which may have 1 or 2 substituents, and m and n are independent of each other and are any integer from 1 to 20.]

[0010] Here, the "substituents" that may be included in R 1 in the above formula (1) are independent of each other and include, for example, an alkyl group, a phenyl group, a hydroxyl group, an alkoxyl group and the like. Further, these substituents may be substituted with another functional group (for example, an alkyl group, a phenyl group, etc.). Also, the above alkyl group may be linear, branched or cyclic.

[0011] The propylene oxide-added diepoxy resin (a1) of the above formula (1) can be obtained by known methods. For example, the above R 1 It can be obtained by adding or addition polymerization of propylene oxide to a polyol compound having hydroxyl groups at both ends, and then reacting the resulting polyether compound (which has hydroxyl groups at both ends) with epichlorohydrin to diexify it.

[0012] The above R 1 Examples of polyol compounds having hydroxyl groups at both ends include: linear or cyclic alkylene glycols in which hydroxyl groups are bonded to carbon atoms at both ends, such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,4-cyclohexanediol; polyhydric phenols having two or more hydroxyl groups, such as catechol, resorcinol, hydroquinone, and pyrogallol; polyphenol compounds or their hydrogenates, such as 2,2-bis(4-hydroxycyclohexyl)propane (hydrogenated bisphenol A), hydrogenated bisphenol F, hydrogenated bisphenol E, hydrogenated bisphenol B, hydrogenated bisphenol AP, hydrogenated bisphenol BP, bisphenol A, bisphenol F, bisphenol E, bisphenol B, bisphenol AP, and bisphenol BP; and so on.

[0013] The propylene oxide-added diepoxy resin (a1) of formula (1) may be used alone or in combination of two or more in the production of a modified epoxy resin. When producing a modified epoxy resin using two or more propylene oxide-added diepoxy resins (a1) of formula (1), they may be added separately or simultaneously.

[0014] Bisphenol compounds (a2) include, for example, bisphenol A, bisphenol F, bisphenol E, bisphenol B, bisphenol S, bisphenol AP, bisphenol BP, etc. Among them, bisphenol A and bisphenol F are preferred. The bisphenol compound (a2) may be used alone or in combination of two or more in the production of modified epoxy resins. When producing a modified epoxy resin using two or more bisphenol compounds (a2), they may be added separately or simultaneously.

[0015] The diepoxy resin (a3) is a compound having two epoxy groups in one molecule, which is different from the above propylene oxide-added diepoxy resin (a1). The diepoxy resin (a3) is not particularly limited, but preferably has an epoxy equivalent within the range of 170 or more and 500 or less, more preferably 170 or more and 400 or less. The diepoxy resin (a3) is not particularly limited, but is preferably a compound represented by the above formula (2). In formula (2), R 3 and R 4 may be the same or different, and examples thereof include a single bond, an alkylene group, a phenylene group or a cyclohexylene group. X 1 and Y 1 are each independently a hydrogen atom or an alkyl group. The alkyl group as X 1 and Y 1 is not particularly limited as long as it is linear or branched, but an alkyl group having 1 to 6 carbon atoms is preferred, and an alkyl group having 1 to 3 carbon atoms is more preferred.

[0016]

Chemical formula

[0017] The above-mentioned diexo resin (a3) ​​can be obtained by reacting two hydroxyl groups in a polyol compound with an epihalohydrin (e.g., epichlorohydrin) to perform diexification.Examples of the above polyol compounds include: linear or cyclic alkylene glycols in which hydroxyl groups are bonded to carbon atoms at both ends, such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,4-cyclohexanediol; polyhydric phenols having two or more hydroxyl groups, such as catechol, resorcinol, hydroquinone, and pyrogallol; and 2,2-bis(4-hydroxycyclohexyl)pro Pan(Hydrogenated Bisphenol A), Hydrogenated Bisphenol F, Hydrogenated Bisphenol E, Hydrogenated Bisphenol B, Hydrogenated Bisphenol AP, Hydrogenated Bisphenol BP, Bisphenol A, Bisphenol F, Bisphenol E, Bisphenol B, Bisphenol AP, Bisphenol BP, 4,4'-Dihydroxybenzophenone, Bis(4-Hydrogenated Phenyle)-1,1-Isobutane, Bis(4-Hydrogenated-2-Tert-Butylphenyl)-2,2-Propane, Bis(4-Hydrogenated-3-Tert-Butylphenyl)-2,2-Propane Polyphenol compounds or their hydrides such as bis(2-hydroxynaphthyl)methane, tetrakis(4-hydroxyphenyl)-1,1,2,2-ethane, 4,4'-dihydroxydiphenylsulfone, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, bis(4-hydroxyphenyl)-2,2-dichloroethylene, 2,2-bis(3-methyl-4-hydroxyphenyl)propane; and polyphenol compounds such as 1,1-dihydroxyethane, 1,1-dihydroxypropane, and 2,2-dihydroxypropane, in which two hydroxyl groups are bonded to the same carbon atom. Alkylene glycols; alkylene glycols in which one hydroxyl group and one hydroxyalkyl group are bonded to the same carbon atom, such as 2-hydroxypropanol and 2-hydroxybutanol; alkylene glycols in which one or two hydroxyalkyl groups are bonded to the same carbon atom, such as 2,2-(dihydroxymethyl)ethane, 2,2-(dihydroxyethyl)propane, 2,2-dimethyl-1,3-propanediol, 2,2-dimethyl-1,4-butanediol, and 3,3-diethyl-1,6-hexanediol; 4-(1-hydroxyethyl)pheno. Alkylene glycols in which one hydroxyl group and one phenol group are bonded to the same carbon atom, such as 3-(1-hydroxyethyl)phenol and 4-(1-hydroxypropyl)phenol; alkylene glycols in which one hydroxyl group and one cyclohexanol group are bonded to the same carbon atom, such as 4-(1-hydroxyethyl)cyclohexanol and 2-(1-hydroxyethyl)cyclohexanol; alkylene glycols in which one hydroxyalkyl group and one phenol group are bonded to the same carbon atom, such as 4-hydroxyphenyl-2-propanol and 4-hydroxyphenyl-2-butanol Examples include alkylene glycols, such as 2-(4-hydroxycyclohexyl)-1-propanol and 2,2-dimethyl-2-(4-hydroxycyclohexyl)-1-ethanol, in which one hydroxyalkyl group and one cyclohexanol group are bonded to the same carbon atom; and alkylene glycols, such as 2-(4-hydroxyphenyl)-2-(4-hydroxycyclohexyl)propane and 1-(4-hydroxyphenyl)-1-(4-hydroxycyclohexyl)propane, in which one phenol group and one cyclohexanol group are bonded to the same carbon atom.

[0018] Diepoxy resin (a3) ​​may be used alone or in combination of two or more types in the production of modified epoxy resin. When using two or more types of diepoxy resin (a3) ​​to produce modified epoxy resin, they may be added separately or simultaneously.

[0019] Dicarboxylic acids (a4) are compounds in which two carboxyl groups are bonded via at least one carbon atom. Preferred dicarboxylic acids are those in which two carboxyl groups are bonded via a linear alkylene group (R) having 1 to 20 carbon atoms, as shown in formula (6) below. 2 It is a compound that is bonded via (R). Note that the alkylene group (R) in the compound of formula (6) 2) may have one or more substituents selected from alkyl groups, alkenyl groups, alkadienyl groups, and methylene groups, or one or more substituents each selected from alkyl groups, alkenyl groups, alkadienyl groups, and methylene groups. Also, the alkylene group (R) in the compound of formula (6) 2 If the alkylene group has 2 to 20 carbon atoms, a ring may be formed via adjacent carbon atoms of the alkylene group. The ring may have one or more substituents selected from alkyl groups and alkenyl groups, and preferably two substituents of alkyl and / or alkenyl groups. If the ring has two substituents, the two substituents may be the same or different. Examples of rings include bicyclo rings in which two carbon-carbon bonds are double bonds, such as cyclohexane rings, cyclohexene rings, benzene rings, and decalin rings (e.g., bicyclo[4.4.0]decane-1,7-diene). 2 The alkyl group, alkenyl group, or alkadienyl group that the ring may have, or the alkyl group or alkenyl group that the ring may have, may be linear or branched.

[0020] [ka]

[0021] A more preferred dicarboxylic acid (a4) is a compound having a cyclic and / or unsaturated bond. Particularly preferred dicarboxylic acid (a4) is a compound of formula (6) that has an alkylene group (R 2 The number of carbon atoms in the ) is 2 to 18, and the alkylene group (R 2 ) comprises one methylene group, one or two alkyl groups having 5 to 9 carbon atoms, or two substituents selected from alkyl groups, alkenyl groups, and alkadienyl groups having 5 to 9 carbon atoms. It may have, or an alkylene group (R 2The compound is one of the above rings, which are formed via adjacent carbon atoms of ), and each ring may independently have two substituents, which are alkyl groups, alkenyl groups, or alkadienyl groups having 5 to 9 carbon atoms.

[0022] Dicarboxylic acids (a4) include, for example, malonic acid, succinic acid, glutaric acid, 2,2-dimethylglutaric acid, 3,3-dimethylglutaric acid, adipic acid, 2,2-dimethyladipic acid, pimelic acid, suberic acid, azelaic acid, 2-ethylazelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, and 1,13-tridecanedicarboxylic acid. Examples include rubonic acid, 1,14-tetradecanedicarboxylic acid, 1,15-pentadecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,17-heptadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, 1,19-nonadecanedicarboxylic acid, 1,20-icosaneticarboxylic acid, itaconic acid, phthalic acid, dimer acid, 1,2-cyclohexanedicarboxylic acid, 1,2-cyclohexenedicarboxylic acid, etc. Dicarboxylic acid (a4) may be used alone or in combination of two or more in the production of modified epoxy resin. When producing a modified epoxy resin using two or more dicarboxylic acids (a4), they may be added separately or simultaneously.

[0023] Dimer acids that can be used as raw materials for modified epoxy resins include, for example, commercially available Harima Dimer 200, 250 or 270S (Harima Chemicals Group Co., Ltd.); Tsuno Dimer 205, 216, 228, 395 or 346 (Tsukuno Foods Industry Co., Ltd.); Unydyme 14, 14R, T-17, 18, T-18, 22, T-22, 27, 35, M-9, M-15, M-35 or 40, or Century D-75, D-77, D-78 or D-1156, or Sylvatall 7001 or 7002 (Arizona Chemical Corporation); Empol 1016, 1003, 1026, 1028, 1061, 1062, 1008 or 1012 (BASF Corporation); hydrogenated dimer acid (average Examples include Mn~570 (Sigma-Aldrich).

[0024] <Amine compound (A2)> The amine compound (A2) is a raw material for introducing amino groups into the epoxy resin (A1). Therefore, the amine compound (A2) contains at least one active hydrogen that can react with the epoxy group. The amine compound (A2) is not particularly limited as long as it can introduce amino groups, and for example, alkylamines and alkanolamines can be used. Examples of alkylamines include monomethylamine, dimethylamine, monoethylamine, diethylamine, monoisopropylamine, diisopropylamine, monobutylamine, dibutylamine, ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, tetraethylenepentamine, pentaethylenehexamine, diethylaminopropylamine, and diethylenetriamine. Examples of alkanolamines include monoethanolamine, diethanolamine, mono(2-hydroxypropyl)amine, di(2-hydroxypropyl)amine, monomethylaminoethanol, and monoethylaminoethanol. Of these, alkanolamines are preferred. In addition, ketiminated primary amines can also be used. These amine compounds may be used individually or in combination of two or more. When producing a cationic epoxy resin (A) using two or more amine compounds (A2), they may be added separately or simultaneously.

[0025] <Method for manufacturing epoxy resin (A1)> Next, the method for producing epoxy resin (A1) will be described in detail. Epoxy resin (A1) is, for example, a mixture of raw materials including propylene oxide-added diepoxy resin (a1), bisphenol compound (a2), diepoxy resin (a3), and dicarboxylic acid (a4). It can be manufactured by stirring and reacting at a constant temperature. Furthermore, it is preferable to add a reaction catalyst to the above mixture to accelerate the reaction.

[0026] The reaction catalyst is not particularly limited as long as it promotes the reaction, but for example, tertiary amines such as dimethylbenzylamine, triethylamine, and tributylamine, and quaternary ammonium salts such as tetraethylammonium bromide and tetrabutylammonium bromide can be used. The reaction temperature should preferably be controlled between 70°C and 200°C to allow the reaction to proceed.

[0027] The epoxy equivalent of the epoxy resin (A1) obtained by the above manufacturing method is preferably between 1000 and 5000, more preferably between 1250 and 4000, and particularly preferably between 1500 and 3000. Using epoxy resin (A1) within this range as a raw material for cationic epoxy resin (A) makes it possible to produce a cationic electrodeposition coating composition that achieves superior liquid stability and efficiently forms a predetermined film thickness. The epoxy equivalent can be measured according to the potentiometric titration method of JIS K7236. This measurement can be performed using a commercially available potentiometric titrator (for example, the AT-610 manufactured by Kyoto Electronics Manufacturing Co., Ltd.).

[0028] In the production of epoxy resin (A1), the blending ratios of propylene oxide-added diepoxy resin (a1), bisphenol compound (a2), diepoxy resin (a3), and dicarboxylic acid (a4) are as follows in relation to the total mass of each raw material (a1) to (a4): The propylene oxide-added diepoxy resin (a1) is preferably 1 to 50% by mass, more preferably 5 to 45% by mass, and most preferably 10 to 40% by mass. The dicarboxylic acid (a4) is preferably 1 to 20% by mass, more preferably 5 to 20% by mass, and most preferably 10 to 20% by mass. The remaining blending ratio is determined by the bisphenol compound (a2) and diepoxy resin (a3), but it is desirable that the bisphenol compound (a2) and diepoxy resin (a3) ​​be 1% by mass or more.

[0029] The above reactions may be carried out in a solvent by adding each raw material to the solvent as appropriate. The solvent is not particularly limited as long as it is one that is normally used in the manufacture of resins, and examples include hydrocarbon solvents such as toluene, xylene, and hexane; ester solvents such as methyl acetate and ethyl acetate; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; amide solvents such as dimethylformamide and dimethylacetamide; alcohol solvents such as methanol, ethanol, and isopropanol; and ether alcohol solvents such as ethylene glycol monobutyl ether and ethylene glycol monohexyl ether. These may be used individually or in combination of two or more.

[0030] <Method for manufacturing cationic epoxy resin (A)> Next, the method for producing the cationic epoxy resin (A) will be described in detail. First, the epoxy resin (A1) and the amine compound (A2) are reacted. The reaction temperature and time are preferably 1 to 5 hours within the range of 70°C to 110°C. In the production of the resin, it is preferable to adjust the amount of amine compound (A2) so that the amine value of the resin is in the range of 5 mg KOH / g to 30 mg KOH / g. Therefore, the amine value of the obtained resin is preferably in the range of 5 mg KOH / g to 30 mg KOH / g, more preferably in the range of 5 mg KOH / g to 20 mg KOH / g, and particularly preferably in the range of 10 mg KOH / g to 20 mg KOH / g. The amine value, i.e., the total amine value of the resin, is measured in accordance with the potentiometric titration method of JIS K7237. It is possible.

[0031] Furthermore, if unreacted epoxy groups remain even after adjusting the amine value, the epoxy groups will react. The unreacted epoxy group may be reacted with a suitable compound. The compound used to react with the unreacted epoxy group is not particularly limited, but examples include phenolic compounds, carboxylic acids, xyleneformaldehyde resin, and ε-caprolactone.

[0032] The reaction between the epoxy resin (A1) and the amine compound (A2) described above can use the same solvent used in the production of the epoxy resin (A1), but is not limited to these, and other solvents may also be used.

[0033] A cationic epoxy resin (A) can be obtained by cationizing the amino groups contained in the structure of an amino group-modified epoxy resin obtained by reacting an epoxy resin (A1) with an amine compound (A2) using an organic acid. The organic acid is not particularly limited as long as it can cationize the amino groups in the above amino group-modified epoxy resin, and can be used for example: organic carboxylic acids such as formic acid, acetic acid, and lactic acid; organic sulfonic acids such as sulfamic acid and methanesulfonic acid; etc. Of these, it is desirable to use methanesulfonic acid, which can produce a more stable low-amine value resin emulsion. These acids can be used individually or in combination of two or more. When using two or more acids, they may be added separately or simultaneously. Cationization may be performed on all amino groups or on some of the amino groups. The amount of organic acid used for cationization is, for example, 0.1 equivalents to 1.0 equivalents, preferably 0.25 equivalents to 0.75 equivalents, relative to the number of moles of amino groups.

[0034] The content of cationic epoxy resin (A) in the cationic electrodeposition coating composition is not particularly limited, but is preferably 50 g / L to 250 g / L, and more preferably 100 g / L to 200 g / L.

[0035] <Blocked polyisocyanate curing agent (D)> The blocked polyisocyanate curing agent (D) is the addition reaction product of a polyisocyanate compound and a blocking agent, preferably the addition reaction product of a polyisocyanate compound and a blocking agent in approximately stoichiometric amounts. Examples of polyisocyanate compounds include tolylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, diphenylmethane-2,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, polymeric MDI (crude MDI), bis(isocyanate-methyl)cyclohexane, tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, isophorone diisocyanate, and the like. These can be used individually or in combination of two or more.

[0036] Furthermore, the blocking agent is added to the isocyanate group of the polyisocyanate compound to block the reaction of other compounds. The blocked polyisocyanate compound produced by blocking the isocyanate group with the blocking agent is stable at room temperature. It is desirable that the blocked polyisocyanate compound is one in which the blocking agent can dissociate when the coating film formed by the cationic electrodeposition coating composition of the present invention is baked. The baking temperature is usually about 100 to 200°C.

[0037] Examples of blocking agents that meet these requirements include: lactam compounds such as ε-caprolactam and γ-butyrolactam; oxime compounds such as methyl ethyl ketoxime and cyclohexanone oxime; phenolic compounds such as phenol, para-t-butylphenol, and cresol; alcohols such as n-butanol and 2-ethylhexanol; and ether alcohol compounds such as ethylene glycol monobutyl ether and ethylene glycol monohexyl ether. These blocking agents can be used individually or in combination of two or more. These can be used in combination. To efficiently carry out the addition and dissociation reactions of the blocking agent, and to efficiently obtain the intended addition reaction product, the hydroxyl groups in the modified epoxy resin may be reacted with the isocyanate groups in the polyisocyanate compound beforehand, and some or all of the other isocyanate groups in the polyisocyanate compound may be blocked with the blocking agent.

[0038] Furthermore, to further improve the efficiency of the addition and dissociation reactions of the blocking agent, a curing catalyst may be added as appropriate. A commercially available curing catalyst can be used as appropriate. The content of the blocked polyisocyanate curing agent (D) in the cationic electrodeposition coating composition is not particularly limited, but is preferably 15 g / L to 75 g / L, and more preferably 30 g / L to 60 g / L.

[0039] <Method for manufacturing resin emulsion> The cationic epoxy resin (A) may, as appropriate, be in the form of a resin emulsion dispersed in water. The resin emulsion can be produced by diluting a resin cationized with an organic acid with water while stirring.

[0040] The amount of acid used for cationization is not particularly limited, but if it is too little, the amount of cationization that imparts water dispersibility may be insufficient, and the emulsion may not form. Therefore, it is preferable to adjust the amount of acid as appropriate.

[0041] The resin emulsion may contain other raw materials. Examples of other raw materials include blocked polyisocyanate curing agents (D), liquid media (preferably water), pigment paste (containing pigment and resin for dispersing the pigment), organic solvents, surfactants, defoamers, antibacterial agents, and other additives used in cationic electrodeposition coatings.

[0042] <Organic acid zinc compound (B)> The cationic electrodeposition coating composition contains at least one type of zinc organic acid compound. Specific examples of zinc organic acid compounds include, for example, zinc formate, zinc acetate, zinc lactate, zinc gluconate, zinc tranexamate, zinc dipropionate, and zinc methanesulfonate. In particular, it is preferable to use at least one selected from the group consisting of zinc lactate, zinc acetate, and zinc methanesulfonate, and of these, zinc acetate is the most preferable.

[0043] The content of the organic acid zinc compound in the cationic electrodeposition coating composition is not particularly limited, but is preferably 10 ppm to 1000 ppm in terms of divalent zinc ions, more preferably 100 ppm to 500 ppm, and even more preferably 150 ppm to 350 ppm. The amount of divalent zinc ions contained in the composition can be quantified using an ICP emission spectrometer.

[0044] <Phenol compound (C)> The cationic electrodeposition coating composition contains a phenol compound (C). Examples of phenol compounds (C) include phenols and phenol resins. Examples of phenols include phenol, alkyl-substituted phenols, polyhydric phenols, α-naphthol, bisphenol, and polyvinylphenol. Examples of alkyl-substituted phenols include cresol, xylenol, butylphenol, and amylphenol. Examples of polyhydric phenols include resorcinol and catechol. Examples of bisphenols include bisphenol A and bisphenol F. Examples of phenol resins include reaction products of the above phenols and formaldehyde. The form of the reaction product between the phenol and formaldehyde is not particularly limited, and examples include novolac and resol. The phenol compound (C) may be the Mannich reaction product of the above phenols and / or phenol resins, formaldehyde, and amines. The above Mannich reaction product of the phenols and / or phenol resins, formaldehyde, and amines may be used as is, or it may be used after being cationized with an organic acid. The phenol compound (C) may be used alone, or two or more may be used in combination. Of the above, it is preferable to use the Mannich reaction product of phenols and / or phenol resins, formaldehyde, and amines as the phenol compound (C), and it is more preferable to use the Mannich reaction product of phenols and / or phenol resins, formaldehyde, and amines that has been cationized with an organic acid.

[0045] The above-mentioned formaldehyde can be formaldehyde itself, a compound that produces formaldehyde, or the like. Examples of formaldehyde-producing compounds include aldehyde derivatives, aliphatic aldehydes, aromatic aldehydes, and heterocyclic aldehydes. Examples of aldehyde derivatives include paraformaldehyde and hexamethylenetetramine. Examples of aliphatic aldehydes include acetaldehyde and propionaldehyde. Examples of aromatic aldehydes include benzaldehyde, and examples of heterocyclic aldehydes include furfural. These may be used individually or in combination of two or more. Among these, formaldehyde is preferred.

[0046] The above-mentioned amines can include primary amines, secondary amines, etc. Examples of primary amines include primary alkylamines, primary hydroxyalkylamines, and primary aromatic amines. Examples of primary alkylamines include methylamine, ethylamine, propylamine, isopropylamine, and butylamine. Examples of primary hydroxyalkylamines include ethanolamine, propanolamine, and isopropanolamine. Examples of primary aromatic amines include aniline. Examples of secondary amines include secondary alkylamines and secondary hydroxyalkylamines. Examples of secondary alkylamines include dimethylamine, diethylamine, ethylpropylamine, dipropylamine, diisopropylamine, and dibutylamine. Examples of secondary hydroxyalkylamines include N-methylethanolamine, N-ethylethanolamine, diethanolamine, dipropanolamine, and diisopropanolamine. These may be used individually or in combination of two or more. Among these, secondary hydroxyalkylamines are preferred, and among them, N-methylethanolamine and diethanolamine are more preferred.

[0047] The Mannich reaction can be carried out using general methods. For example, phenols and / or phenolic resins, formaldehyde, and amines can be mixed and reacted at 20°C to 100°C for several minutes to several hours, optionally using alcohols, glycol ethers, or ketones as solvents. The amounts of each component of phenols and / or phenolic resins, formaldehyde, and amines used in the above Mannich reaction are not particularly limited, as formaldehyde and amines are consumed in equimolar amounts by the Mannich reaction. The progress of the Mannich reaction can be confirmed by quantifying the remaining formaldehyde. There are no particular restrictions on the method of confirming formaldehyde, but for example, the acetylacetone spectrophotometric method described in the Japanese Agricultural Standard JAS 6000 established by the Ministry of Agriculture, Forestry and Fisheries can be used.

[0048] For example, monovalent organic acids and polyvalent organic acids can be used as organic acids for the cationization of the above-mentioned phenols and / or phenolic resins, formaldehyde, and Mannich reaction products of amines. Examples of monovalent organic acids include formic acid, acetic acid, propionic acid, lactic acid, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and benzenesulfonic acid. Acetic acid, toluenesulfonic acid, nitrobenzenesulfonic acid, etc., can be used. As for polyhydric organic acids, citric acid, lactic acid, malic acid, fumaric acid, maleic acid, etc., can be used. Among these, monohydric organic acids are preferred, and acetic acid and methanesulfonic acid are particularly preferred. The content of phenol compound (C) in the cationic electrodeposition coating composition according to the present invention is not particularly limited, but is preferably 10 g / L or more and 200 g / L or less, and more preferably 50 g / L or more and 100 g / L or less. Furthermore, it is preferable that the phenol compound (C) is included in a proportion of 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the cationic epoxy resin (A).

[0049] <Method for producing cationic electrodeposition coating composition> Cationic electrodeposition coating compositions can be manufactured, for example, by stirring and mixing the above-mentioned resin emulsion, organic acid zinc compound (B), and water-soluble phenol compound (C) with the above-mentioned liquid medium, pigment paste, organic solvent, surfactant, defoamer, etc., as needed. The concentration of the cationic electrodeposition coating composition can be adjusted by diluting it with deionized water as appropriate.

[0050] The pH of the cationic electrodeposition coating composition is not particularly limited, but is preferably in the range of 2.0 to 8.0, and more preferably in the range of 3.0 to 6.0. Having the pH of the composition within this range prevents adverse effects from contamination by the chemical conversion solution and metals etched by the chemical conversion treatment, even if a chemical conversion treatment is performed before cationic electrodeposition coating with the cationic electrodeposition coating composition. There are no particular restrictions on the pH adjusting agents that can be used to adjust the pH; known acids and bases can be used. For example, acids such as formic acid, acetic acid, lactic acid, nitric acid, sulfamic acid, methanesulfonic acid, and benzenesulfonic acid, and bases such as ammonia water, monoethanolamine, diethanolamine, and triethanolamine can be used as appropriate. Note that the pH values ​​in this specification are those measured at 25°C using a commercially available pH meter.

[0051] The electrical conductivity of the cationic electrodeposition coating composition is not particularly limited, but it is preferably 1000 μS / cm or more and less than 2000 μS / cm. If it is below 1000 μS, the deposition of the coating film may be delayed during electrodeposition coating, and a sufficient film thickness may not be obtained. If it is above 2000 μS / cm, the appearance of the coating deteriorates and sufficient insulation cannot be obtained. The electrical conductivity can be measured using a commercially available electrical conductivity meter (for example, the MM-60R multi-water quality meter from Toa DKK).

[0052] <Cationic electrodeposition coating method> Cationic electrodeposition coating using a cationic electrodeposition coating composition can be performed by applying an electric current of 10V to 400V, preferably 50V to 250V, with the object to be coated as the cathode. The coating bath containing the cationic electrodeposition coating composition during cationic electrodeposition coating is usually in the range of 10°C to 50°C, preferably 15°C to 40°C, but is not limited to these temperatures. After cationic electrodeposition coating, a drying process is performed to harden the formed coating film. Drying of the coating film is preferably performed in the temperature range of approximately 100°C to approximately 300°C on the surface of the coated object, and more preferably in the temperature range of approximately 150°C to approximately 250°C. In this way, by drying and curing the coating film, an article having a coating film painted with a cationic electrodeposition coating composition is obtained. A water rinsing step may be provided between the cationic electrodeposition coating step and the drying step, if necessary. The water rinsing step can be carried out using, for example, an ultrafiltrate, reverse osmosis permeate, industrial water, or pure water.

[0053] The thickness of the coating film formed by the above cationic electrodeposition coating method is not particularly limited, but is 5 μm. A thickness of 50 μm or less is preferable, and 10 μm to 40 μm is more preferable. Within this range, excellent corrosion resistance can be obtained. The coating thickness can be measured using an electromagnetic induction type thickness gauge if the base metal is a magnetic metal, or an overcurrent type thickness gauge if the base metal is a non-magnetic metal.

[0054] <Electronic Components> The articles to which the cationic electrodeposition coating composition can be applied are not particularly limited, but electronic components are preferred. The electronic components are not particularly limited as long as they can be electrodeposited, and examples include electronic components that make up a motor (core, stator, rotor), lead wires, flat wires, and copper wires. It can be applied to reactor copper, resolvers, busbars, bobbins, inductors, capacitors, transformers, sintered magnets, component housings, adhesives, optical materials (e.g., those represented by imaging lenses), resists, liquid resists, printing plates, insulating varnishes, insulating sheets, laminates, printed circuit boards, encapsulants (e.g., for semiconductor devices, LED packages, liquid crystal injection ports, organic EL devices, optical elements, electrical insulation, electronic components, and separation films), passivation films (e.g., for semiconductors and solar cells), interlayer insulating films, protective films, etc. There are no particular restrictions on the metal materials that make up electronic components, and it can be applied to cold-rolled steel, zinc-plated steel (e.g., alloyed hot-dip galvanized steel, hot-dip galvanized steel, electro-galvanized steel), aluminum steel, aluminum, copper (oxygen-free copper, brass), magnesium, etc. These metal materials may be surface-cleaned by alkaline degreasing or other methods as needed, or surface-cleaned and then subjected to surface treatments such as zinc phosphate conversion treatment or zirconium conversion treatment. Furthermore, these electronic components can be applied to, for example, automotive parts, household appliances, and the like.

[0055] <Other uses> Furthermore, applications to materials other than electronic components include eyeglasses, lining agents, inks, molding materials, putties, glass fiber impregnating agents, sealing agents, prism lens sheets (for example, those used in the backlights of liquid crystal displays), Fresnel lens sheets (for example, those used in the screens of projection televisions, etc.), the lens portion of lens sheets such as lenticular lens sheets, or backlights using such sheets, optical lenses (for example, microlenses, etc.), optical elements, optical connectors, optical waveguides, and casting agents for optical fabrication.

[0056] <Examples> The present invention will be described in more detail below with reference to manufacturing examples, examples, and comparative examples, but the present invention is not limited thereto. The metal plates and degreasing agents used in the examples were arbitrarily selected from commercially available materials and do not limit the actual uses of the cationic electrodeposition coating composition of the present invention. Unless otherwise specified, % and parts refer to mass percent and parts by mass, respectively. The raw materials used in the formulation are shown in Tables 1 to 4 below.

[0057] <Manufacturing of amino group-modified epoxy resin> <Manufacturing Example 1> In a 2-liter separable flask equipped with a thermometer, reflux condenser, and stirrer, 77.25 g of diepoxy resin (Epolite 3002NN), 96.79 g of bisphenol A, 549.5 g of bisphenol A type diglycidyl ether (jER828EL), 63.24 g of dicarboxylic acid (Hallidimer 270S), and 1.0 g of triethylamine were added and reacted at 160°C until the epoxy equivalent reached 1500. The reaction was then stopped by adding 194.86 g of butyl cellosolve. Subsequently, the temperature was adjusted to 100°C, 14.63 g of diethanolamine was added, and the mixture was reacted for 5 hours to obtain an amino-modified epoxy resin.

[0058] <Manufacturing Example 2> In a 2-liter separable flask equipped with a thermometer, reflux condenser, and stirrer, 114.7 g of bisphenol A, 286.94 g of bisphenol A type diglycidyl ether (jER828EL), and 1.0 g of triethylamine were added and reacted at 160°C until the epoxy equivalent reached 1500. The reaction was then stopped by adding 194.86 g of butyl cellosolve. Subsequently, the temperature was adjusted to 100°C, 52.93 g of diethanolamine was added, and the mixture was reacted for 5 hours to obtain an amino-modified epoxy resin.

[0059] <Manufacturing of Blocked Polyisocyanate Curing Agent (D)> <Manufacturing Example 3> In a reaction vessel, 678.4 g of Cosmonate M-200 (trade name, Crude MDI, manufactured by Mitsui Chemicals, Inc.) was added to 115.6 g of methyl isobutyl ketone, and the temperature was raised to 70°C. Then, 706.0 g of butyl cellosolve was slowly added dropwise, and the temperature was raised to 90°C after the addition was complete. The reaction was carried out at 90°C for 12 hours to obtain a blocked polyisocyanate type curing agent. Infrared absorption spectroscopy showed no absorption originating from unreacted isocyanate groups, confirming that the isocyanate was completely blocked.

[0060] <Manufacturing of cationic epoxy resin (A) emulsion> <Manufacturing Example 4> 649.54 g of the amino-modified epoxy resin obtained in Production Example 1 and 216.51 g of the blocked polyisocyanate obtained in Production Example 3 were mixed, and then 6.69 g of methanesulfonic acid was added and the mixture was uniformly stirred. Then, 1116.79 g of deionized water was added over approximately 10 minutes while vigorously stirring to obtain a cationic epoxy resin (A) emulsion with a solid content of 33%.

[0061] <Manufacturing Example 5> 649.54 g of the amino-modified epoxy resin obtained in Production Example 2 and 216.51 g of the blocked polyisocyanate obtained in Production Example 3 were mixed, and then 24.19 g of methanesulfonic acid was added and the mixture was uniformly stirred. Then, 1099.30 g of deionized water was added over approximately 10 minutes while vigorously stirring to obtain a cationic epoxy resin (A) emulsion with a solid content of 33%.

[0062] <Production of water-soluble phenolic compounds (C)> <Manufacturing Example 6> In a 2-liter separable flask equipped with a thermometer, reflux condenser, and stirrer, 228.3 g of bisphenol A and 500.0 g of ethanol were placed and the temperature was raised to 60°C. Then, 162.3 g of formalin and 150.2 g of methylethanolamine were added dropwise and the mixture was reacted for 5 hours. After that, while maintaining the temperature at 60°C, 120.1 g of acetic acid was added and the mixture was reacted for 1 hour. Finally, 1572.8 g of water was added to produce a water-soluble phenol compound with a solid content of 20%.

[0063] <Manufacturing Examples 7 to 13> Using the same method as in Production Example 6, water-soluble phenol compounds with a solid content of 20% (Production Examples 7-13) were manufactured using the raw materials shown in Table 1.

[0064] [Table 1]

[0065] <Preparation of cationic electrodeposition coating compositions> <Example 1> 910.61 g of the resin emulsion produced in Production Example 4, 3.72 g of zinc lactate, 78.88 g of the water-soluble phenol compound produced in Production Example 6, and 1006.79 g of deionized water were added and stirred to produce a cationic electrodeposition coating composition with a solid content of 16%.

[0066] <Examples 2-23 and Comparative Examples 1-4> A cationic coating composition with a solid content of 16% was prepared using the raw materials shown in Table 2, in the same manner as in Example 1.

[0067] [Table 2]

[0068] <Preparation of test panels> To prepare the test plates, first, a metal plate (cold-rolled steel plate: indicated as CRS in the table (150mm (length) x 70mm (width) x 0.8mm (thickness)), aluminum alloy plate: indicated as Al (A5051) in the table, oxygen-free copper plate: indicated as Cu (C1020) in the table, or galvanized steel plate: indicated as GA in the table) was degreased (using Fine Cleaner E6400, manufactured by Nippon Parkerizing Co., Ltd., product name: 60℃ x 3 minutes dip treatment), and then cleaned by rinsing with water. Next, the cleaned metal plate was used as the substrate and electrodeposited using the cationic electrodeposition coating compositions of Examples 1 to 23 and Comparative Examples 1 to 4 to obtain test plates for each example and comparative example by electrodeposition coating to a dry film thickness of 20 μm.

[0069] <Various evaluations> The test plates (electrodeposited coated plates) obtained using the above method were evaluated as follows. The results are shown in Table 3.

[0070] <Dielectric Breakdown Voltage> The dielectric breakdown voltage (dielectric breakdown voltage per unit thickness) of each test board was measured using a dielectric strength tester (TOS9201, manufactured by Kikusui Electronics Co., Ltd.). The measurement was performed under the conditions of an initial voltage of 0V, a boost rate of 50V / sec, and a cutoff current of 1.0mA. The following criteria were used for evaluation, with a score of △ or higher considered a pass. ◎:120V / μm or more ○: 100V / μm or higher, and less than 120V / μm △: 80V / μm or higher, and less than 100V / μm ×: Less than 80V / μm

[0071] <Edge covering properties> The coating thickness of each test plate was measured using an electromagnetic induction coating thickness gauge if the base metal was a magnetic metal, and an eddy current coating thickness gauge if the base metal was a non-magnetic metal, and the coating thickness at the center of the surface of the test plate was determined. Next, the edges of each test plate were cut out and embedded in cups containing epoxy resin. The resin was then cured, and the painted edges were polished. The painted edges were then observed using a Keyence VHX-6000 digital microscope set to 300x magnification. The film thickness at the edges was calculated using data analysis software compatible with this device, and the resulting film thickness was adopted as the numerical value for the edge film thickness. The ratio of the film thickness at the edges to the film thickness at the center of the surface of the test plate was calculated and defined as the edge coverage rate. This was evaluated according to the following criteria, with a score of △ or higher being considered acceptable. ◎: 90% or more ○: 70% or more, and less than 90% △: 50% or more, and less than 70% ×: Less than 50%

[0072] <Pinhole Test> Referring to JIS3261-5:2019, the test plate was immersed in a 0.2% saline solution, with the sample as the cathode and the saline solution as the anode, and a 12V DC power supply was applied for 1 minute. If there were no pinholes, nothing would happen, but if there were pinholes, bubbles would be generated from the electrolysis of water. The number of bubbles was counted and evaluated according to the following criteria, with a score of △ or higher being considered a pass. ◎: No bubbles formed. ○: One or two bubbles are generated. △: 3 to 5 bubbles are generated. ×: More than 6 bubbles are generated.

[0073] [Table 3]

Claims

1. A cationic electrodeposition coating composition comprising a cationic epoxy resin (A), an organic acid zinc compound (B), and a phenol compound (C), wherein the phenol compound (C) comprises phenols and / or phenol resins, formaldehyde, and Mannich reaction products of amines.

2. The cationic electrodeposition coating composition according to claim 1, wherein the aforementioned organic acid zinc compound (B) is contained in an amount of 10 ppm to 1000 ppm on an equivalent basis of divalent zinc ions.

3. The cationic electrodeposition coating composition according to claim 1, wherein the phenol compound (C) is contained in an amount of 1 to 20 parts by mass per 100 parts by mass of the cationic epoxy resin (A).

4. The aforementioned phenols and / or phenolic resins, formaldehyde, and Mannich reaction products of amines include those cationized with organic acids. The aforementioned amines include at least one selected from N-methylethanolamine and diethanolamine. The cationic electrodeposition coating composition according to claim 1, wherein the organic acid comprises a monovalent organic acid.

5. The cationic epoxy resin is obtained by reacting an epoxy resin (A1) with an amine compound (A2) to obtain an amino group-modified epoxy resin, which is then cationized with an organic acid. The epoxy resin (A1) is The constituent units derived from the propylene oxide-added diepoxy resin (a1) represented by formula (1), A constituent unit derived from the bisphenol compound (a2), A constituent unit derived from a different diepoxy resin (a3) ​​than formula (1), A constituent unit derived from a dicarboxylic acid (a4) in which two carboxyl groups are bonded via at least one carbon atom, The cationic electrodeposition coating composition according to claim 1, wherein the resin has the properties of the resin. 【Chemistry 1】 [In formula (1), R １ [wherein Rc is a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, and C3-C10 is a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, and C3-C10 is a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, a C3-C10 alkylene group which may have substituents, or

6. Furthermore, the cationic electrodeposition coating composition according to claim 1 further comprises a blocked polyisocyanate curing agent (D).

7. An electronic component having a coating film painted with the cationic electrodeposition coating composition according to any one of claims 1 to 6.

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