JP2009227821A - Method for forming electrodeposition coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming an electrodeposition coating film, achieving formation of a coating film having more uniform coating film appearance of a coating film on a horizontal face part and of a coating film on a vertical face part of a coated material. <P>SOLUTION: The method comprises subjecting a coating object having a three-dimensional figure to electrodeposition to form an electrodeposition coating film and characterized in that: an electrodeposition coating composition used for the electrodeposition coating contains (a) a pigment anti-settling agent comprising a fatty acid, a fatty acid derivative, an amine compound, or a mixture of at least two kinds selected from the above three kinds, and (b) an inorganic pigment; and the content of the pigment anti-settling agent (a) in the electrodeposition coating composition ranges from 5 to 20 mass% with respect to the whole mass of the inorganic pigment (b). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of forming an electrodeposition coating film by electrodeposition coating on a three-dimensional object to be coated, and the coating film appearance of the coating on the horizontal surface portion and the coating film on the vertical surface portion of the object is more uniform. It is related with the electrodeposition coating-film formation method which provides the coating film which is.

  Electrodeposition coating is a coating method performed by immersing an object to be coated as an electrode in an electrodeposition coating composition and applying a voltage. In this method, even an object to be coated having a complicated shape can be applied to the details, and can be applied automatically and continuously. It has been widely put into practical use as an undercoating method for objects to be coated.

  Examples of the pigment blended in the electrodeposition coating composition include a rust preventive pigment, an extender pigment, a color pigment, and the like, and these are properly used according to the purpose. In the electrodeposition coating composition, the pigment is in a state of being dispersed in a solvent together with the pigment dispersion resin, but those having a high specific gravity are likely to settle. In particular, when the electrodeposition coating composition contains an inorganic pigment, sedimentation occurs even if the electrodeposition coating composition is left for several hours. In order to prevent sedimentation of the pigment and agglomeration of the resulting sediment, it is necessary to constantly stir the interior of the electrodeposition tank regardless of whether or not the electrodeposition coating is stopped.

  However, in an electrodeposition coating composition in which pigments and the like are dispersed in water, precipitation of the pigments and the like occurs even when stirring is performed during electrodeposition coating. It will fall on the horizontal plane. In such a case, when the object to be coated has a three-dimensional shape having a horizontal plane and a vertical plane, it is particularly formed on a coating film on which a pile of pigments or the like formed on the horizontal plane is generated and a vertical plane not accompanied by the pile. There was a problem that the appearance of the coating film, such as coating film gloss, was different from that of the coated film.

  Japanese Patent Application Laid-Open No. 2005-200506 (Patent Document 1) discloses a cationic electrodeposition coating containing resin fine particles having an average particle size of 0.5 to 10 μm in an amount of 1 to 30% by mass with respect to the solid content of the coating. A composition is described. It is described that this electrodeposition coating composition can provide a cured coating film that is excellent in rust prevention at the end face of the object and has a good finished appearance. The electrodeposition coating composition described in Patent Document 1 is a method of forming a coating film having a good finished appearance by controlling the viscosity of the electrodeposition coating film in a favorable range by containing specific resin fine particles. Therefore, the solution of the technical problem is different from the present invention.

  In Japanese Patent Application Laid-Open No. 2005-247992 (Patent Document 2) filed by the present applicant, it is selected from the group consisting of (a) fatty acids, fatty acid derivatives, amine compounds and one or a mixture of two or more thereof. A pigment anti-settling agent, and (b) an electrodeposition coating composition containing the pigment. The electrodeposition coating composition described here has a feature that it is very excellent in pigment dispersion stability. However, in the electrodeposition coating composition used for the coating of various coating materials, it is more difficult to form a coating film having a uniform coating film appearance. There is room for further study.

JP 2005-200506 A JP-A-2005-247992

  The present invention solves the above-mentioned conventional problems, and the object of the present invention is to form a coating film having a more uniform appearance of the coating film on the horizontal surface portion and the coating film on the vertical surface portion of the object to be coated. An object of the present invention is to provide an electrodeposition coating film forming method that can be used.

The present invention
A method of electrodeposition coating on a three-dimensional object to form an electrodeposition coating film,
The electrodeposition coating composition used for this electrodeposition coating is
(A) a pigment antisettling agent which is a fatty acid, a derivative of fatty acid, an amine compound, or a mixture of at least two selected from these three types, and (b) an inorganic pigment,
Including
In the electrodeposition coating composition, the content of the pigment anti-settling agent (a) is 5 to 20% by mass with respect to the total mass of the inorganic pigment (b).
An electrodeposition coating film forming method is provided, whereby the above object is achieved.

  The inorganic pigment (b) preferably contains an extender having an oil absorption of 70 ml / 100 g or less.

  In addition, in the electrodeposition coating film forming method for forming an electrodeposition coating film on a three-dimensional object to be coated, the gloss value of the coating film formed on the horizontal surface portion and the coating film formed on the vertical surface portion of the object to be coated The difference is preferably 25 or less.

  The electrodeposition coating film forming method of the present invention is used to electrodeposit a three-dimensional object to be coated, regardless of the orientation of the surface of the object or the shape of the object. A coating film having a small difference and a more uniform coating film appearance can be formed.

  The present invention relates to a method of forming an electrodeposition coating film by electrodeposition-coating an object having a three-dimensional shape using an electrodeposition coating composition. Hereinafter, the electrodeposition coating composition used in the present invention will be described.

Electrodeposition coating composition In the electrodeposition coating film forming method of the present invention, (a) a pigment settling inhibitor which is a fatty acid, a derivative of fatty acid, an amine compound, or a mixture of at least two selected from these three types, And (b) an electrodeposition coating composition containing an inorganic pigment. The electrodeposition coating composition used in the present invention can be classified into two types: a cationic electrodeposition coating composition using a cationic resin as a main resin and an anionic electrodeposition coating composition using an anionic resin as a main resin. it can. The electrodeposition coating compositions used in the present invention are used in a concept including all. First, the cationic electrodeposition coating composition will be described. The anion electrodeposition coating composition will be described later.

Cationic electrodeposition coating composition The cationic electrodeposition coating composition used in the present invention comprises (a) a fatty acid, a derivative of a fatty acid, an amine compound, or a mixture of at least two selected from these three types to prevent pigment settling. And (b) a binder resin containing a cationic resin and a block polyisocyanate curing agent, and a curing catalyst. In the present specification, “fatty acid” and “derivative of fatty acid” are sometimes collectively referred to as “fatty acids”.

Cationic resin
Cationic Epoxy Resin The cationic resin used in the present invention includes an amine-modified epoxy resin. Cationic resins typically open all of the epoxy rings of bisphenol-type epoxy resins with active hydrogen compounds that can introduce cationic groups, or some epoxy rings with other active hydrogen compounds. And the remaining epoxy ring is opened with an active hydrogen compound capable of introducing a cationic group.

  A typical example of the bisphenol type epoxy resin is a bisphenol A type or bisphenol F type epoxy resin. As the former commercial product, there are Epicoat 828 (manufactured by Yuka Shell Epoxy Co., Epoxy Equivalent 180-190), Epicoat 1001 (Same, Epoxy Equivalent 450-500), Epicoat 1010 (Same, Epoxy Equivalent 3000-4000), etc. Examples of the latter commercially available product include Epicoat 807 (same as above, epoxy equivalent 170).

  Active hydrogen compounds capable of introducing a cationic group include primary amines, secondary amines, tertiary amine acid salts, sulfides and acid mixtures. In the present invention, in order to prepare a primary, secondary or / and tertiary amino group-containing epoxy resin, an acid salt of a primary amine, secondary amine or tertiary amine is used as an active hydrogen compound capable of introducing a cationic group. Use.

  Specific examples include butylamine, octylamine, diethylamine, dibutylamine, methylbutylamine, monoethanolamine, diethanolamine, N-methylethanolamine, triethylamine hydrochloride, N, N-dimethylethanolamine acetate, diethyl disulfide / acetic acid mixture, etc. In addition, there are secondary amines in which primary amines such as aminoethylethanolamine ketimine and diethylenetriamine diketimine are blocked. A plurality of amines may be used in combination.

Cationic Acrylic Resin The cationic electrodeposition coating composition used in the present invention may contain a cationic acrylic resin as necessary. This is because it is possible to prevent a decrease in oil repellency that may occur when the content of the inorganic pigment (b) is small. The cationic acrylic resin can be produced by a ring-opening addition reaction between an acrylic copolymer containing a plurality of oxirane rings in the molecule and an amine. Such acrylic polymers include (i) glycidyl (meth) acrylate and (ii) hydroxyl group-containing acrylic monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, Plaxel FA and FM It is obtained by copolymerizing an addition reaction product of 2-hydroxyethyl (meth) acrylate and caprolactone known as a series with (iii) other acrylic and / or non-acrylic monomers. Examples of other acrylic and non-acrylic monomers are methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) ) Acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, styrene, vinyl ketone, α-methylstyrene, (meth) acrylonitrile, (meth) acrylamide, Such as vinyl acetate.

  In the acrylic copolymer containing an oxirane ring, the entire oxirane ring is converted into a primary amine, secondary amine or tertiary amine in the same manner as when an oxirane ring of an epoxy resin is opened with an amine to introduce a cationic group. By opening the ring by reaction with an amine acid salt, a cationic acrylic resin can be obtained.

  As another method, a cationic acrylic resin can be obtained by copolymerizing an acrylic monomer having an amino group with another monomer. In this case, an amino group-containing acrylic monomer is used in place of the above-mentioned (i) glycidyl (meth) acrylate. Examples of the amino group-containing acrylic monomer include amino group-containing acrylic monomers such as N, N-dimethylaminoethyl (meth) acrylate and N, N-di-t-butylaminoethyl (meth) acrylate.

  The cationic acrylic resin is a conventional method so that the number average molecular weight of the polymer is in the range of 1,000 to 20,000, preferably 2,000 to 10,000, more preferably 5,000 to 10,000. Can be obtained by copolymerizing the monomers.

  It is preferable that the compounding quantity of a cationic acrylic resin is 10-100 mass parts with respect to 100 mass parts of resin solid content in a cationic electrodeposition coating composition.

The blocked polyisocyanate curing agent cationic electrodeposition coating composition contains a blocked polyisocyanate curing agent obtained by blocking polyisocyanate with a blocking agent. Here, the polyisocyanate means a compound having two or more isocyanate groups in one molecule. The polyisocyanate may be, for example, any of aliphatic, alicyclic, aromatic and aromatic-aliphatic.

  Specific examples of polyisocyanates include aromatic diisocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), p-phenylene diisocyanate, and naphthalene diisocyanate; hexamethylene diisocyanate (HDI), 2,2,4- C3-C12 aliphatic diisocyanates such as trimethylhexane diisocyanate and lysine diisocyanate; 1,4-cyclohexane diisocyanate (CDI), isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) , Methylcyclohexane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, and 1,3-diisocyanatomethyl Such as chlorohexane (hydrogenated XDI), hydrogenated TDI, 2,5- or 2,6-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane (also referred to as norbornane diisocyanate), and the like. Aliphatic diisocyanates having 5 to 18 carbon atoms; aliphatic diisocyanates having aromatic rings such as xylylene diisocyanate (XDI) and tetramethylxylylene diisocyanate (TMXDI); modified products of these diisocyanates (urethanes, carbodiimides) Uretdione, uretoimine, burette and / or isocyanurate modified product); These may be used alone or in combination of two or more.

  Adducts or prepolymers obtained by reacting polyisocyanates with polyhydric alcohols such as ethylene glycol, propylene glycol, trimethylolpropane and hexanetriol at an NCO / OH ratio of 2 or more may also be used as the block polyisocyanate curing agent.

  Preferred specific examples of the aliphatic polyisocyanate or alicyclic polyisocyanate include hexamethylene diisocyanate, hydrogenated TDI, hydrogenated MDI, hydrogenated XDI, IPDI, norbornane diisocyanate, dimer (biuret) and trimer thereof. (Isocyanurate) etc. are mentioned.

  The blocking agent is added to a polyisocyanate group and is stable at ordinary temperature, but can regenerate a free isocyanate group when heated to a temperature higher than the dissociation temperature.

  As a blocking agent, when low temperature curing (160 ° C. or lower) is desired, lactam blocking agents such as ε-caprolactam, δ-valerolactam, γ-butyrolactam and β-propiolactam, and formaldoxime, acetoald It is preferable to use an oxime blocking agent such as oxime, acetoxime, methyl ethyl ketoxime, diacetyl monooxime, and cyclohexane oxime.

Inorganic pigment (b)
The cationic electrodeposition coating composition used in the present invention contains a commonly used pigment. As the pigment, an inorganic pigment (b), an organic pigment, carbon black or a combination thereof is contained. The inorganic pigment (b) is mainly classified into a color pigment, an extender pigment and an antirust pigment. In addition, extender pigments are generally insoluble in the vehicle used, and are in the form of granules or powders, and certain performances of paints and coatings (anti-repellency, chipping resistance, coating hardness, weather resistance, adhesion, etc.) This means a pigment blended for the purpose of reforming (according to JIS K5500). Specific examples of the inorganic pigment (b) include, for example, colored pigments such as titanium white, carbon black and bengara; extender pigments such as kaolin, talc, aluminum silicate, calcium carbonate, mica, clay and silica; zinc phosphate Of iron phosphate, aluminum phosphate, calcium phosphate, zinc phosphite, zinc cyanide, zinc oxide, aluminum tripolyphosphate, zinc molybdate, aluminum molybdate, calcium molybdate and aluminum phosphomolybdate, zinc phosphomolybdate Rust preventive pigments, and the like. In the present specification, the “organic pigment” is used in the concept of contrasting with the inorganic pigment (b). Examples of organic pigments include colored pigments such as phthalocyanine blue, phthalocyanine green, monoazo yellow, disazo yellow, benzimidazolone yellow, quinacridone red, monoazo red, boriazo red, and berylene red.

  In the present invention, any of the above pigments can be used. These may be used alone or in combination of two or more.

  The inorganic pigment (b) is generally contained in the cationic electrodeposition coating composition in an amount that occupies a lower limit of 1% by mass and an upper limit of 60% by mass with respect to the total solid content of the cationic electrodeposition coating composition. The upper limit is preferably 30% by mass.

  In the present invention, as the inorganic pigment (b), an extender pigment having an oil absorption of 70 ml / 100 g or less is preferably included. Body pigments such as kaolin, talc, aluminum silicate, calcium carbonate, mica, clay, barium sulfate and silica that can improve performance such as repellency prevention, chipping resistance, coating film hardness, weather resistance, adhesion, etc. In general, the specific gravity tends to be higher than other pigments such as colored pigments or rust preventive pigments. Such a pigment having a high specific gravity tends to cause sedimentation particularly in an electrodeposition coating composition that is a low solid content concentration water-dispersed coating. On the other hand, in the method of the present invention, even when a pigment having a high specific gravity is used, there is an advantage that an effect that the gloss difference of the obtained coating film is small and the coating film appearance becomes more uniform can be obtained. When the oil absorption amount of the extender pigment exceeds 70 ml / 100 g, the film thickness difference between the coating film on the horizontal surface portion and the coating film on the vertical surface portion may increase. The oil absorption of the extender pigment is more preferably 4 to 70 ml / 100 g, and further preferably 4 to 55 ml / 100 g.

  Specifically, in the present invention, by using an electrodeposition coating composition containing an extender pigment having an oil absorption of 70 ml / 100 g or less, the difference in gloss between the coating film on the horizontal surface portion and the coating film on the vertical surface portion is reduced. There is an advantage that the film thickness difference of the coating film can be reduced. By using an extender having an oil absorption of 70 ml / 100 g or less in the present invention, the inorganic pigment (b) settles on the horizontal surface of the coating object when the coating object is immersed in the electrodeposition coating composition. It can be prevented from adhering. Thereby, the fall of the electrodeposition coating film deposition in the horizontal surface of a to-be-coated object and the film thickness of the electrodeposition coating film formed can be prevented from falling. A coating film having a uniform thickness can be formed regardless of the orientation of the surface of the object to be coated, and an excessive film thickness and use of an excessive amount of electrodeposition coating composition and coating energy can be prevented.

  In the present invention, the extender pigment is more preferably contained in an amount of 15 to 95% by mass based on the total mass of the inorganic pigment (b).

The oil absorption amount in the present invention is measured by a kneading method (based on Rub-out Method or JIS K5101), and is defined as sardine oil (JIS K 5421) which is absorbed by the pigment under certain conditions. It is obtained by measuring the amount of refined sesame oil (acid value of 5.0 to 7.0) according to JIS K5101. The operation is as follows.
(I) Take 1 to 5 g of a sample weighed with a chemical scale weighing to the order of 10 mg in the center of a measuring plate (smooth glass plate larger than 300 mm × 400 mm × 5 mm), and boil oil (JIS) 4 to 5 drops at a time from the one specified in R 3505 (up to 10 ml) to the center of the sample, each time with a spatula (steel or stainless steel blade) Knead well).
(Ii) Repeat dripping and kneading, and when the whole becomes a hard putty-like lump, knead every drop, and when the last one drop can be wound in a spiral shape using a spatula, the end point And However, if it cannot be spirally wound, the end point is the point immediately before it becomes soft with a drop of oil.
(Iii) The operations of (i) and (ii) are adjusted so that the operation time until reaching the end point is 7 to 15 minutes.
(Iv) The amount of oil dripping is read in the boiled sesame in the burette when the end point is reached.
(V) When comparing with a sample, the operations (i) to (iv) are also performed for the sample.

Pigment settling inhibitor (a)
The cationic electrodeposition coating composition used in the present invention is an anti-settling pigment pigment which is a fatty acid, a derivative of fatty acid (both are referred to as fatty acids), an amine compound, or a mixture of at least two selected from these three types. Contains agent (a). In the present invention, the dispersion stability of the pigment contained in the coating composition is improved by adding the pigment anti-settling agent (a) to the electrodeposition coating composition. And although it is an electrodeposition coating composition containing an inorganic pigment (b), there is little pigment sediment even when the electrodeposition coating composition is allowed to stand without stirring. Can be manufactured. As a result, even when electrodepositing a three-dimensional object to be coated, an electrodeposition coating film capable of obtaining a uniform gloss regardless of the direction of the object surface or the shape of the object. An electrodeposition coating composition that can be formed is obtained.

  When electrodepositing a three-dimensional object to be coated using a general electrodeposition coating composition, the reason why the coating film appearance varies due to the orientation of the surface of the object is as follows: The cause of this is considered. For example, the reason why the gloss of the coating film varies depending on the orientation of the surface of the object to be coated is that the inorganic pigment (b) dispersed in the electrodeposition coating composition settles on the electrodeposition coating film. . In particular, the inorganic pigment (b) settles on the horizontal surface of the article to be coated. And when an inorganic pigment (b) settles on the electrodeposition coating film formed in the horizontal surface of a to-be-coated article, the electrodeposition coating film of a horizontal surface has the unevenness | corrugation derived from the settled inorganic pigment (b). It will be. And since an electrodeposition coating film has this unevenness | corrugation, even after baking hardening, a coating-film gloss will be inferior. The reason why the thickness of the coating film varies depending on the orientation of the surface of the object to be coated is that the inorganic pigment (b) dispersed in the electrodeposition coating composition settles on the object to be coated. . When the object to be coated is immersed in the electrodeposition coating composition, the horizontal surface of the object to be coated at the time of electrodeposition coating is as follows: the inorganic pigment (b) settles and adheres to the horizontal surface of the object to be coated. As compared with other aspects, the conductivity is inferior. Thereby, compared with other surfaces, the horizontal surface of the object to be coated is less likely to deposit the electrodeposition coating film, and the film thickness of the electrodeposition coating film to be formed is reduced. Thereby, the thickness of the coating film to be formed varies depending on the orientation of the surface of the object to be coated. And when the thickness of the coating film differs depending on the orientation of the surface of the object to be coated, in order to secure the minimum film thickness required for exhibiting the physical properties of the coating film, the surface where the coating film thickness becomes excessive Will occur. Therefore, an excessive amount of the electrodeposition coating composition and the coating energy is used, and there is a disadvantage that the coating cost increases.

  In contrast, the electrodeposition coating composition used in the method of the present invention contains the inorganic pigment (b), but the electrodeposition coating composition is left standing without stirring. Even if it exists, it has the characteristics that there are few pigment sediments. Therefore, even when electrodeposition is applied to an object having a three-dimensional shape, the gloss is uniform regardless of the surface orientation of the object or the shape of the object without the disadvantages described above. And there is an advantage that a uniform film thickness can be obtained.

  The fatty acids that can be used as the pigment settling inhibitor (a) are fatty acids or derivatives thereof as described above. Examples of fatty acids include linear saturated fatty acids, branched saturated fatty acids, and unsaturated fatty acids. Examples of fatty acid derivatives include fatty acid esters obtained by modifying the above fatty acids with alcohols, polyhydric alcohols (glycerin, ethylene glycol, polyethylene glycol, etc.), fatty acid ethylene oxide adducts or fatty acid propylene oxides modified with ethylene oxide or propylene oxide. Adducts, fatty acid amide compounds modified with amine compounds, and polyfunctional fatty acids are included. These fatty acid esters or fatty acid amide compounds also include those obtained by ring-opening addition of ethylene oxide (ethylene oxide ring-opening adduct). These fatty acids contain chemical bonds such as unsaturated bonds, ether bonds and ester bonds, functional groups such as hydroxyl groups, amino groups and carbonyl groups, and heteroatoms such as oxygen, nitrogen, sulfur and halogen in the molecular skeleton. You may go out. Polyfunctional carboxylic acids and the like are also included in the fatty acid derivatives. As fatty acid derivatives, it is more preferable to use fatty acid esters, fatty acid amide compounds, and these ethylene oxide ring-opening adducts.

  The fatty acids used in the present invention are preferably fatty acids having 4 to 22 carbon atoms and derivatives thereof, more preferably fatty acids having 7 to 20 carbon atoms and derivatives thereof.

Specific fatty acids include, for example, the following compounds:
(1) Linear saturated fatty acid arachidic acid, tricosanoic acid, behenic acid, heneicosanoic acid, eicosanoic acid, nonadecanoic acid, stearic acid, heptadecanoic acid, palmitic acid, pentadecanoic acid, myristic acid, tridecanoic acid, lauric acid, capric acid, capryl Acid, octanoic acid, heptanoic acid, hexanoic acid, valeric acid, butyric acid, etc., refined stearic acid (450V, 550V, 700V), etc. manufactured by Kao Corporation;
(2) Branched saturated fatty acid isostearic acid, methyltetradecanoic acid, methylheptadecanoic acid, methyloctadecanoic acid, isovaleric acid and the like;
(3) unsaturated fatty acid oleic acid, ricinoleic acid, linoleic acid, linolenic acid, eleostearic acid, elaidic acid, palmitoleic acid, arachidonic acid, undecenoic acid, sorbic acid, crotonic acid and the like;
(4) Multifunctional carboxylic acid suberic acid, azelaic acid, sebacic acid, brassylic acid, phthalic acid, dodecanedioic acid, tetrahydrophthalic acid, hexahydrophthalic acid, tetrabromophthalic acid, tetrachlorophthalic acid, 3-tert-butyl Adipic acid, trimellitic acid, pyromellitic acid, etc .;
(5) Hetero atom-containing fatty acid hexyloxyacetic acid, dimethylolpropionic acid, dimethylolbutanoic acid, salicylic acid, benzoic acid, p-butoxybenzoic acid, N-acetylglycine, N-acetyl-β-alanine, thioctic acid and the like;
(6) Fatty acid ester (alcohol ester type)
Lion's Kadenax (GS-90, SO-80C), Kao's Rheodor (SP-L10, SP-P10, SP-S10V, SP-S30V, AS-10, AO-10, AO-15V), Kao Rheodor Super SP-L10 manufactured by Kao, Emazol manufactured by Kao Corporation (L-10 (F), P-10 (F), S-10V, O-10V), etc .;
(7) Fatty acid ester (ethylene glycol, polyethylene glycol ester type)
Lion Rionon (DT-600S, DEH-40), Asahi Denka Kogyo Adekaestor (OEG-102, OEG-106), etc .;
(8) Fatty acid methyl ester (ethylene oxide, propylene oxide addition system)
Lion Leo Fat (LA-110M-95, OC-0503M), Kao Emanon (1112,3199,3299,4110, CH-25, CH-40, CH-60 (K), CH-80), etc. (9) Fatty acid ethylene oxide adducts Lion's Esophat (O / 15, O / 20,60 / 15), Asahi Denka Kogyo's Adekaestor (TL-144, TL-161, TL-162, S-60, S-80, T-81, T-82), Kao Rheodor (TW-L120, TW-L106, TW-P120, TW-S120V, TW-S106, TW-S320V, TW-O120V, TW-O106V, TW-O320V, TW-IS399C, 430,440,460), Kao's Leodoll Super TW-L120, etc .;
(10) Fatty acid ester (glycerin ester type)
(11) Fatty acid amide compounds such as Kao's Exel T-95, VS-95, O-95R, 200, 300, 122V, P-40S) and Kao's Rheodor (MS-50, MS-60, MO-60, MS165V) A saturated fatty acid monoamide compound that is lauric acid amide, stearic acid amide, palmitic acid amide, caproic acid amide, caprylic acid amide, capric acid amide, myristic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide and the like;
(12) Unsaturated fatty acid monoamide oleic acid amide, erucic acid amide, ricinoleic acid amide, palmitic acid amide, behenic acid amide, brassinic acid amide, esylic acid amide, linoleic acid amide, linolenic acid amide, rice sugar Examples of these industrial products such as fatty acid amide and palm fatty acid amide include Kao wax (EB-G, EB-P, EB-FF, 85-P, 220, 230-2) manufactured by Kao Corporation, and fatty acid amide manufactured by Kao Corporation. S, T, ON, E), Adekasol YA manufactured by Asahi Denka Kogyo Co., Ltd. and the like;
(13) Saturated fatty acid bisamides that are fatty acid amide compounds, methylene bis-stearic acid amide, ethylene bis-capric acid amide, ethylene bis-lauric acid amide, ethylene bis-stearic acid amide, ethylene bis-isostearic acid amide, ethylene bis-hydroxystearic acid amide, ethylene Bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene bishydroxystearic acid amide, N, N′-distearyl adipic acid amide, N, N′-distearyl sebacic acid amide, methylene Bispalmitic acid amide, ethylene bispalmitic acid amide, methylene bisbehenic acid amide, ethylene bisbehenic acid amide, hexaethylene bispalmitic acid amide, etc .;
(14) Unsaturated fatty acid bisamides that are fatty acid amide compounds, ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide, and the like;
(15) Substituted amides which are fatty acid amide compounds N-stearyl stearic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl palmitic acid Acid amides;
(16) Aromatic bisamides methylol stearic acid amides which are fatty acid amide compounds; methylol amides such as methylol behenic acid amide, N, N-distearylisophthalic acid amide, metaxylylene bis stearic acid amide;
(17) Branched amides which are fatty acid amide compounds N, N′-2-hydroxyethyl stearic acid amide, N, N′-ethylenebisoleic acid amide, N, N′-xylene bisstearic acid amide, N, N '-Dioleoyl adipic acid amide, N, N'-dioleyl sebacic acid amide, N, N'-distearyl isophthalic acid amide, etc .;
(18) Alkanolamides which are fatty acid amide compounds Palm oil fatty acid monoethanolamide, lauric acid monoethanolamide, myristic acid monoethanolamide, oleic acid monoethanolamide, coconut oil fatty acid diethanolamide, lauric acid diethanolamide, myristic acid diethanolamid Industrial products such as lime, dioleamide, oleic acid diethanolamide, palm oil fatty acid monopropanolamide, lauric acid monopropanolamide, myristic acid monopropanolamide, oleic acid monopropanolamide, polyoxyalkylene alkanolamide ), Lion's armor slip (CP, E, EY), etc .;
However, it is not limited to these.

  The amine compound is preferably an amine compound in which an alkyl chain having 4 or more carbon atoms is bonded to a nitrogen atom. There may be one alkyl chain bonded to the nitrogen atom, or two or more alkyl chains may be bonded. As these amine compounds, any of primary, secondary and tertiary amines may be used. These amine compounds may have a plurality of amino groups in the skeleton, or the skeleton itself may be modified with ethylene oxide or the like. The amine compound used in the present invention preferably has 4 to 22 carbon atoms in the alkyl chain, more preferably 7 to 20 carbon atoms in the alkyl chain.

Specific examples of amine compounds include the following:
(1) Primary amine compound (1-1) Aliphatic mono- and polyamine compounds
n-butylamine, amylamine, n-hexylamine, heptylamine, n-octylamine, nonylamine, laurylamine, tetradecylamine, cetylamine, stearylamine, 2,4-butanediamine, 1,6-hexamethylenediamine, 1, Aliphatic primary amine compounds such as 8-octamethylenediamine,
(1-2) Alicyclic mono- and polyamine compounds cyclohexylamine, 1,3- and 1,4-diaminocyclohexane, 1,3- and 1,4-bis (aminomethyl) cyclohexane, 3-aminomethyl-3, Alicyclic primary amine compounds such as 5,5-trimethyl-1-aminocyclohexane, bis (4-aminocyclohexyl) methane, 1-methyl-2,4-diaminocyclohexane, 1-methyl-2,6-diaminocyclohexane Kind,
(1-3) Aromatic mono- and polyamine compounds aniline, meta- and paratoluidine, naphthylamine, 1,3- and 1,4-phenylenediamine, 1-methyl-2,4-diaminobenzene, 1-methyl-2,6 -Aromatic primary amine compounds such as diaminobenzene, 2,4,-and 4,4, -diaminodiphenylmethane, 4,4, -diaminobiphenyl, 1,5- and 2,6-naphthalenediamine,
(1-4) Aralkyl mono and polyamine compounds
Aralkyl primary amine compounds such as 1,3- and 1,4-bis (aminomethyl) benzene, 1,5- and 2,6-bis (aminomethyl) naphthalene,
These industrial products include Lion's Armin (CD, OD, TD, HT, 8D, 12D, 14D, 16D, 18D), Kao's Farmin (CS, 08D, 20D, 80, 86T, O, T), etc. Can be mentioned;
(2) Secondary amine compounds di-n-butylamine, diisoamylamine, dibenzylamine, methyldiethylethylenediamine, methylaniline, piperidine, 1,2,3,4-tetrahydroisoquinoline, 6-methoxy-1,2,3 Secondary amines such as, 4-tetrahydroisoquinoline, morpholine, N-methyl-glucamine, glucosamine, t-butylamine,
These industrial products include Kao's Farmin (D86) and the like;
(3) tertiary amine compounds such as tri (n-butyl) amine, tetramethylethylenediamine, 1-methylpiperidine, 1-methylpyrrolidine, 4-dimethylaminopyridine, triethylenediamine, bisdimethylaminoethyl ether, triisopropanolamine, etc. Grade amines,
These industrial products include Lion's Armin (DMMCD, DMTD, DMMHTD, DM12D, DM14D, DM16D, DM18D, DM22D, M2HT, M2O, M210D), Kao's Farmin (DM24C, DM0898, DM1098, DM2098, DM2465, DM2463) DM2458, DM4098, DM4662, DM6098, DM6875, DM8680, DM8098, DM2285, M2-2095, T-08) and the like;
(4) Alkanolamine Kao Aminone (PK-02S, L-02), etc .;
(5) Modified amine (5-1) Alkylamine ethylene oxide adduct Lion Esomin (C / 12, C / 15, C / 25, T / 12, T / 15, T / 25, S / 15, S / 25, O / 12, O / 17, O / 20, HT / 12, HT / 14, HT / 17), Lion esomide (HT / 15, HT / 60, O / 15), Asahi Denka Kogyo Co., Ltd. Made Adekasol (CO, COA, CMA, YA-6), Kao Amit (105,320);
However, it is not limited to these.

  These fatty acids and amine compounds may be used alone or in combination of two or more. More preferable examples of the pigment settling inhibitor include fatty acids having 4 to 22 carbon atoms, derivatives of fatty acids having 4 to 22 carbon atoms, and mixtures of these two types.

  Although the action mechanism in which the dispersibility of the inorganic pigment (b) is improved by adding a fatty acid or an amine compound is not clear, for example, the fatty acid has a structure like a monomolecular film or two molecules of the inorganic pigment (b). It is considered that the arrangement of the structure like a film is taken, and thereby the resistance of the inorganic pigment (b) to water is increased, and the precipitation of the inorganic pigment (b) is prevented. In the present invention, the fatty acids or amine compounds used as the pigment anti-settling agent (a) have a high ability to be arranged in a structure such as a molecular film, and thus are considered to be excellent in performance for preventing the precipitation of the inorganic pigment (b). It is done. As a result, an electrodeposition coating composition capable of forming an electrodeposition coating film having excellent gloss uniformity even when electrodepositing an object having a three-dimensional shape is obtained.

  The pigment settling inhibitor (a) is contained in the electrodeposition coating composition in an amount occupying 5 to 20% by mass with respect to the total mass of the inorganic pigment (b) contained in the electrodeposition coating composition. The content of the pigment settling inhibitor (a) is more preferably 10 to 20% by mass. When the amount of the pigment anti-settling agent (a) is less than 5% by mass, the desired gloss uniformity effect may not be obtained. On the other hand, when the amount of the pigment anti-settling agent (a) exceeds 20% by mass, the corrosion resistance (rust resistance) may be lowered, or the viscosity may be increased to make it difficult to prepare a coating material.

When a pigment such as a cationic pigment dispersion paste inorganic pigment (b) is used as a component of an electrodeposition coating composition, the pigment is generally dispersed in an aqueous medium at a high concentration in advance together with a resin called a pigment dispersion resin to form a paste. This is because the pigment is in a powder form, and it is difficult to disperse in one step in a low concentration uniform state used in the electrodeposition coating composition. Such a paste is generally called a pigment dispersion paste. When a solid curing catalyst is used, it may be added when preparing the pigment dispersion paste, or may be added in another paint manufacturing process.

  As the cationic pigment dispersion resin, a cationic or nonionic low molecular weight surfactant or a modified epoxy resin having a quaternary ammonium group and / or a tertiary sulfonium group is generally used. As the aqueous medium, ion-exchanged water or water containing a small amount of alcohol is used. Generally, the pigment dispersion resin is used in a ratio of 20 to 40% by mass in the solid content of the pigment dispersion paste, and the pigment and the solid curing catalyst are used in a ratio of 60 to 80% by mass. The cationic pigment dispersion paste is prepared by mixing a cationic pigment dispersion resin, a pigment, and, if necessary, a neutralizing agent such as an acid and an aqueous medium, and then the pigment in the mixture has a predetermined uniform particle size. Until it becomes, it can be obtained by dispersing using a normal dispersing device such as a ball mill or a sand grind mill.

Curing Catalyst The cationic electrodeposition coating composition used in the present invention can promote the dissociation of the blocking agent of the block polyisocyanate curing agent by adding a curing catalyst. The curing catalyst used in the present invention is not particularly limited as long as it promotes dissociation of the blocking agent of the curing agent, and a typical curing catalyst includes a tin catalyst. Examples of the tin catalyst include solid catalysts such as dibutyltin oxide, dioctyltin oxide, monobutyltin oxide and mixtures thereof, liquid tin catalysts such as dibutyltin dilaurate, and mixtures thereof.

  The said curing catalyst is mix | blended in the quantity of 0.5-10 mass% with respect to the resin solid content in an electrodeposition coating composition, Preferably it is 1-5 mass%.

Preparation of cationic electrodeposition coating composition The cationic electrodeposition coating composition used in the present invention comprises a cationic resin and a blocked polyisocyanate curing agent dispersed in an aqueous medium (cationic main emulsion), and if necessary. It is prepared by mixing a cationic acrylic resin and a blocked polyisocyanate curing agent used in an aqueous medium (subemulsion), a pigment dispersion paste, and deionized water in a predetermined ratio.

  In the preparation of the cationic electrodeposition coating composition used in the present invention, the pigment settling inhibitor (a) can be added at any dispersion / mixing stage. The pigment settling inhibitor (a) is preferably added to the above-mentioned cationic pigment dispersion paste, and then mixed with other components such as a cationic main emulsion. In this case, it is because it is excellent in the performance which prevents sedimentation of a pigment.

  As an aqueous medium, for example, ion exchange water can be used, and a small amount of alcohols may be included. The aqueous medium contains a neutralizing agent in order to improve the dispersibility of the cationic resin. Neutralizing agents are inorganic or organic acids such as hydrochloric acid, nitric acid, phosphoric acid, formic acid, acetic acid, lactic acid. The amount is that which achieves a neutralization rate of at least 20%, preferably 30-60%.

  The amount of the block polyisocyanate curing agent is sufficient to react with active hydrogen-containing functional groups such as primary, secondary and / or tertiary amino groups and hydroxyl groups in the cationic resin during curing to give a good cured coating film. It must be sufficient and generally ranges from 90/10 to 50/50, preferably from 80/20 to 65/35, expressed as a mass ratio of cationic resin to blocked polyisocyanate curing agent.

  The electrodeposition coating composition can contain conventional coating additives such as water-miscible organic solvents, surfactants, antioxidants, and UV absorbers.

Anionic electrodeposition coating composition The anionic electrodeposition coating composition of the present invention is different from the above-mentioned cationic electrodeposition coating composition in the binder resin and the curing catalyst. Since other components are common, only the differences will be described below.

In the anionic resin anionic electrodeposition coating composition, an anionic resin is used instead of the cationic resin. As the anionic resin used in the present invention, a resin having a carboxyl group and optionally further a hydroxyl group, which are well known in the field of electrodeposition coating compositions, can be used. As the anionic resin, for example, an acrylic resin having a carboxyl group or a polyurethane resin having a carboxyl group is preferably used, and an acrylic resin having a carboxyl group and a hydroxyl group or a polyurethane resin having a carboxyl group and a hydroxyl group is particularly preferably used. This is because the coating film is excellent in weather resistance and smoothness.

  As the acrylic resin having a carboxyl group and a hydroxyl group, for example, a carboxyl group-containing unsaturated monomer, a hydroxyl group-containing acrylic monomer, and, if necessary, other polymerizable monomers are used, and these monomers are radically polymerized. Copolymers can be used.

  A carboxyl group-containing unsaturated monomer is a compound having at least one carboxyl group and a polymerizable unsaturated bond in one molecule. For example, (meth) acrylic acid, itaconic acid, maleic acid, caprolactone-modified carboxyl group-containing ( And (meth) acrylic monomers.

  The hydroxyl group-containing acrylic monomer is a compound having at least one hydroxyl group and a polymerizable unsaturated bond in one molecule. For example, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate Hydroxyalkyl (meth) acrylates such as; (poly) ethylene glycol mono (meth) acrylate, (poly) alkylene glycol mono (meth) acrylates such as (poly) propylene glycol mono (meth) acrylate; and these hydroxyl group-containing acrylic monomers And β-propiolactone, dimethylpropiolactone, butyrolactone, γ-valerolactone, γ-caprolactone, γ-caprolactone, γ-lauryllactone, ε-caprolactone, and δ-caprolactone. Examples of commercially available products include Plaxel FM1 (trade name, caprolactone-modified (meth) acrylic acid hydroxy esters), Plaxel FM2 (same as left), Plaxel FM3 ( Same as left), Plaxel FA1 (same as left), Plaxel FA2 (same as left), Plaxel FA3 (same as left) and the like.

The other polymerizable monomer is a compound having at least one polymerizable unsaturated bond in one molecule other than the above carboxyl group-containing unsaturated monomer and hydroxyl group-containing acrylic monomer. For example, (meth) acrylic Methyl methacrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, (meth) acrylic acid C ₁ -C ₁₈ alkyl or cycloalkyl esters of (meth) acrylic acid such as cyclohexyl; aromatic polymerizable monomers such as styrene, α-methylstyrene, vinyltoluene; (meth) acrylic acid amide, N-butoxymethyl ( (Meth) acrylamide, N-methylol (meth) acrylamide and other (meth) Kurylamide and derivatives thereof; (meth) acrylonitrile compounds; γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, vinyltri Examples include alkoxysilyl group-containing polymerizable monomers such as methoxysilane.

  As a blending ratio of these monomers, it is preferable to use the carboxyl group-containing unsaturated monomer within a range of 3 to 30% by mass, particularly 4 to 20% by mass with respect to the total mass of the monomers. It is preferable to use the hydroxyl group-containing acrylic monomer within a range of 3 to 40% by mass, particularly 5 to 30% by mass with respect to the total mass of the monomers.

  A conventionally known solution polymerization method or the like can be used as a method for radically copolymerizing these monomers.

  Examples of polyurethane resins having a carboxyl group and a hydroxyl group are those obtained by subjecting a polyisocyanate compound, polyols and dihydroxycarboxylic acid to a urethanization reaction by an one-shot method or a multistage method at an equivalent ratio in which the hydroxyl group becomes excessive. Can be given.

  The polyisocyanate compound is a compound having two or more isocyanate groups in one molecule, and examples thereof include aliphatic diisocyanates such as hexamethylene diisocyanate, trimethylhexane diisocyanate, and lysine diisocyanate; cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and methylcyclohexyl. An alicyclic diisocyanate such as silylene diisocyanate is preferably used.

  Polyols are compounds having two or more hydroxyl groups in one molecule, for example, polymerization or copolymerization (blocking) of alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) and / or heterocyclic ether (tetrahydrofuran). Or polyether diol obtained by random), for example, polyethylene glycol, polypropylene glycol, polyethylene-propylene (block or random) glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, polyoctamethylene ether glycol, etc .; dicarboxylic acid (Adipic acid, succinic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid, phthalic acid, etc.) and glycol (ethylene glycol, propylene glycol, etc.) Polyester diols obtained by polycondensation of styrene, butanediol, hexanediol, neopentylglycol, bishydroxymethylcyclohexane, etc., such as polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polyneopentyl adipate, polyethylene -Butylene adipate, polyneopentyl-hexyl adipate, etc .; Polylactone diol, for example, polycaprolactone diol, poly 3-methylvalerolactone diol, etc .; Polycarbonate diol; and a mixture of two or more selected from these. The number average molecular weight of these polyols is generally 500 or more, preferably 500 to 5000, more preferably 1000 to 3000.

  As the polyols, low molecular weight polyols having two or more hydroxyl groups in one molecule and having a number average molecular weight of less than 500 can also be used. Specifically, glycols and their alkylene oxide low-mole adducts (molecular weight less than 500) mentioned above as raw materials for polyester diols; trihydric alcohols such as glycerin, trimethylolethane, trimethylolpropane and the like and their low alkylene oxides. Mole adduct (molecular weight less than 500); a mixture of two or more selected from these, and the like.

  In a system in which a polyol having a number average molecular weight of 500 or more and a low molecular weight polyol having a number average molecular weight of less than 500 are used in combination, the composition ratio of these two polyols is 80 based on the total amount of both polyols. ˜99.9% by weight, in particular 90 to 99.5% by weight, the latter being preferably in the range of 20 to 0.1% by weight, in particular 10 to 0.5% by weight.

  Dihydroxycarboxylic acid is a compound having two hydroxyl groups and one carboxyl group in one molecule, and examples thereof include dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutyric acid, and dimethylolbutanoic acid.

  The urethanization reaction with the polyisocyanate compound, polyols and dihydroxycarboxylic acid described above can be carried out by a method known per se.

In the curing agent anionic electrodeposition coating composition, examples of the curing agent for the anionic resin include melamine resin and block polyisocyanate.

As the melamine resin, ether in which part or all of the methylol group of methylolmelamine obtained by reacting melamine with formaldehyde or the like is modified with one or more alcohols selected from C _{1 to} C ₁₀ monoalcohols. A melamine resin can be used. The melamine resin may contain an imino group, a methylol group, and other functional groups.

  As the block polyisocyanate, the block polyisocyanate curing agent exemplified in the above cationic electrodeposition coating composition can be used.

Anionic pigment dispersion paste When an anionic electrodeposition coating composition contains a pigment such as an inorganic pigment (b), it is preferable to prepare the pigment in the form of a pigment dispersion paste in advance from the viewpoint of easy dispersion of the pigment. An anionic pigment dispersion paste can be prepared by dispersing a pigment in an anionic pigment dispersion resin. As the pigment, the pigments exemplified in the above cationic electrodeposition coating composition can be used.

  For example, a modified acrylic resin having an acrylic ester, acrylic acid and an azonitrile compound can be used as the anionic pigment dispersion resin.

  An anionic pigment dispersion paste can be prepared by adding the above-mentioned anionic pigment dispersion resin, a pigment and a neutralizing agent, and dispersing or dissolving them.

  Generally, the anionic pigment dispersion paste is prepared to a solid content of 35 to 70% by mass, preferably 40 to 65% by mass.

  An anionic pigment dispersion paste is prepared by mixing an anionic pigment dispersion resin and a pigment, and, if necessary, a neutralizing agent such as triethylamine and an aqueous medium, and then the pigment in the mixture has a predetermined uniform particle size. Until it becomes, it can obtain by making it disperse | distribute using a normal dispersion device.

Preparation of anionic electrodeposition coating composition The anionic electrodeposition coating composition used in the present invention is prepared by dispersing the above-described anionic resin and anionic pigment dispersion paste in an aqueous medium. Usually, the aqueous medium contains a neutralized base (amine or alkali compound) in order to neutralize the anionic resin and improve the dispersibility. Specifically, the amine used as the neutralizing base has a low molecular weight having 3 or less carbon atoms, and is different from the above-described pigment settling inhibitor. When the number of carbon atoms is such, the interaction with the resin becomes larger than the interaction with the pigment, so that the effect of the pigment as an anti-settling agent is lost. Examples of neutralizing bases include ammonia; diethylamine, ethylethanolamine, diethanolamine, monoethanolamine, monopropanolamine, isopropanolamine, ethylaminoethylamine, hydroxyethylamine, diethylenetriamine and other organic amines; sodium hydroxide, potassium hydroxide, etc. Basic compounds such as alkali metal hydroxides.

  In the preparation of the anionic electrodeposition coating composition used in the present invention, the pigment settling inhibitor (a) can be added at any of the dispersion and mixing stages. The pigment settling inhibitor (a) is preferably added to the anionic pigment dispersion paste, and then mixed with other components such as an anionic main emulsion. In this case, it is because it is excellent in the performance which prevents sedimentation of a pigment. In addition, the compounding quantity of a fatty acid or an amine compound is the same as the case of a cationic electrodeposition coating composition.

  The amount of the curing agent is generally 90/10 to 50/50, preferably in the range of 80/20 to 50/50, expressed as a solid mass ratio (anionic resin / curing agent) between the anionic resin and the curing agent. is there. The amount of neutralizing base is that which is sufficient to neutralize at least 30%, preferably 50-120% of the anionic groups of the anionic resin.

Electrodeposition coating formation
Coating object A coating object on which an electrodeposition coating film is formed by the method of the present invention is a coating object having a three-dimensional shape. Here, the “object having a three-dimensional shape” means an object having a three-dimensional shape. Specific examples of the three-dimensional object to be coated include, for example, a horizontal plane portion that is substantially parallel to the liquid surface of the electrodeposition coating composition in the electrodeposition tank during electrodeposition coating, and substantially perpendicular to the surface portion. An article to be coated having a vertical surface portion is exemplified. The object to be coated is not particularly limited as long as it has conductivity and can be an electrode in electrodeposition coating, but is preferably a metal substrate. The article to be coated is also preferably subjected to a surface treatment such as zinc phosphate treatment or zirconium treatment in advance.

Electrodeposition coating in the case of using a cationic electrodeposition coating composition as a cationic electrodeposition coating electrodeposition coating composition is usually performed by applying a voltage of 1 to 400 V between the object to be coated as a cathode and an anode. During electrodeposition coating, the bath temperature of the coating composition is adjusted to 10 to 45 ° C, preferably 15 to 30 ° C.
The electrodeposition process includes a process of immersing an object to be coated in a cationic electrodeposition coating composition, and a process of depositing a film by applying a voltage between the object to be coated as a cathode and an anode. The voltage application time, the applied voltage, and the like can be implemented by methods well known to those skilled in the art. The applied voltage during electrodeposition coating may vary greatly and may be in the range of 1 to several hundred volts. After electrodeposition coating, the film formed on the surface of the object is cured by baking. For baking, for example, a baking furnace, an oven, or an infrared heat lamp can be used. The baking temperature is usually 140 ° C to 180 ° C.

Electrodeposition coating in the case of using an anion electrodeposition coating composition as the anion electrodeposition coating electrodeposition coating composition is usually performed by applying a voltage of 1 to 400 V between the object to be coated and the cathode. During electrodeposition coating, the bath temperature of the coating composition is adjusted to 10 to 45 ° C, preferably 15 to 30 ° C, and pH is adjusted to 6.0 to 9.0, preferably 7.0 to 8.0.
The electrodeposition process includes a process of immersing the object to be coated in the anion electrodeposition coating composition and a process of depositing a film by applying a voltage between the object to be coated and the cathode. The voltage application time, the applied voltage, and the like can be implemented by methods well known to those skilled in the art. The applied voltage during electrodeposition coating may vary greatly and may be in the range of 1 to several hundred volts. After electrodeposition coating, the film formed on the surface of the object is cured by baking. For baking, for example, a baking furnace, an oven, or an infrared heat lamp can be used. The baking temperature is usually 140 ° C to 180 ° C.

  The following examples further illustrate the present invention, but the present invention is not limited thereto. In the examples, “parts” and “%” are based on mass unless otherwise specified.

Production Example 1 Preparation of Cationic Resin A reaction vessel equipped with a stirrer, a cooling tube, a nitrogen introduction tube, and a thermometer, Epicoat 1001 (Oilized Shell Epoxy, bisphenol A type epoxy resin having an epoxy equivalent of 475) 99.8 Part, Epicoat 1004 (manufactured by Yuka Shell Epoxy, bisphenol A type epoxy resin having an epoxy equivalent of 950), 55 parts of nonylphenol, 193.3 parts of methyl isobutyl ketone (MIBK) and 4.5 g of benzyldimethylamine were added. , And reacted at 140 ° C. for 4 hours to obtain a resin having an epoxy equivalent of 1175. Here, 69.1 parts of ethylene glycol n-hexyl ether, 35.4 parts of MIBK solution (solid content 78% by mass) of MIBK ketimine product of 2-aminoethylethanolamine, 26.5 parts of N-methylethanolamine, and diethanolamine 37 .1 part was added. This was reacted at 120 ° C. for 2 hours to obtain the desired resin.

Production Example 2 Preparation of Block Polyisocyanate Curing Agent In a five-necked flask equipped with a reflux condenser, a stirrer, a dropping funnel and a nitrogen introduction tube, 199.1 parts of hexamethylene diisocyanate trimer (Coronate EH) and methyl isobutyl ketone 31.6 parts were charged and heated to 40 ° C. in a nitrogen atmosphere. To this was added 0.2 part of dibutyltin dilaurate, and further 87.0 parts of methylethylketoxime was added dropwise over 2 hours from the dropping funnel. After completion of the addition, the reaction was carried out at 70 ° C. until the peak of the isocyanate group disappeared by IR spectrum. It was. After completion of the reaction, 38.1 parts of methyl isobutyl ketone and 1.6 parts of butanol were added and cooled to obtain a block polyisocyanate curing agent having a solid content of 80%.

Production Example 3 Preparation of Epoxy Resin Pigment Dispersion Resin 382 parts of Epicoat 828 and 118 parts of bisphenol A were placed in a reaction vessel and heated to 150 to 160 ° C. in a nitrogen atmosphere. The reaction mixture was reacted at 150-160 ° C. until the epoxy equivalent reached 500. Subsequently, after cooling the reaction mixture to 140 to 145 ° C., 203 parts of 2-ethylhexanol half-blocked toluene diisocyanate was added. The reaction mixture was kept at 140-145 ° C. for about 1 hour and then 209 parts dipropylene glycol monobutyl ether was added. Next, the reaction mixture was cooled to 90 ° C. or lower, and 272 parts of 1- (2-hydroxyethylthio) propan-2-ol, 134 parts of dimethylolpropionic acid, and 144 parts of deionized water were added. This mixture was reacted at 65 to 75 ° C. until an acid value of about 8 was obtained to obtain a pigment dispersing resin. This was cooled and diluted with deionized water to a solids content of 30% to obtain a varnish for pigment dispersion.

Production Example 4 Preparation of Cationic Main Emulsion The cationic resin of Production Example 1 and the polyisocyanate curing agent of Production Example 2 were mixed at a solid content of 70:30, and neutralized with acetic acid to a neutralization rate of 40%. Deionized water was added and diluted slowly, and then methyl isobutyl ketone and deionized water were removed so that the non-volatile content was 37% by mass to obtain a cationic main emulsion as a binder resin emulsion.

Example 1 Preparation of cationic electrodeposition coating composition
Preparation of Cationic Pigment Paste A cationic pigment paste was prepared by dispersing the following blending amount.

^＊１：竹原化学工業株式会社製硫酸バリウム、吸油量４ｍｌ／１００ｇ、平均粒径１．２μｍ
^＊２：ライオン株式会社製、アルコール系脂肪酸エステル
なお上記表中、カーボンブラック：三菱化学株式会社製、ＭＡ−１００、酸化チタン：石原産業株式会社製、タイペークＣＲ−９７である。

^{* 1} : Barium sulfate manufactured by Takehara Chemical Industry Co., Ltd., oil absorption 4 ml / 100 g, average particle size 1.2 μm
^{* 2} : Alcohol fatty acid ester manufactured by Lion Co., Ltd. In the above table, carbon black: manufactured by Mitsubishi Chemical Corporation, MA-100, titanium oxide: manufactured by Ishihara Sangyo Co., Ltd., Type CR-97.

Preparation of Cationic Electrodeposition Coating Composition 35 parts by weight of the cationic main emulsion of Production Example 4, 13.3 parts by weight of the cationic pigment dispersion paste obtained above, and 47.4 parts by weight of deionized water were mixed. A cationic electrodeposition coating composition was obtained.

  4 liters of the obtained cationic electrodeposition coating composition was put into a stainless beaker and stirred for several minutes, and then stirring was stopped. A cold-rolled steel plate (L-shaped plate, 0.8 mm thick steel plate) having the three-dimensional shape shown in FIG. 1 treated with zinc phosphate was immersed in the cationic electrodeposition coating composition up to the dotted line portion of FIG. In this state, the steel plate was allowed to stand for 3 minutes, and then, electricity was applied in a state where stirring was stopped to perform electrodeposition coating. Next, after washing with water, baking was performed at 140 ° C. for 20 minutes. About the obtained electrodeposition coating film, the film thickness and gloss value of the electrodeposition coating film formed in the location of (A) and (C) of FIG. 1 were measured. The measurement results are shown in the following table. The gloss value was measured according to the following procedure.

Gloss value The gloss value of the formed electrodeposition coating film is measured using a micro-TRI-gloss (BYK-Gardner) in accordance with JIS K5600-4-7 with an incident optical axis of 60 °. Measurement was performed three times under geometric conditions (60 ° gloss), and an average value was calculated from these measured values.

The preparation of the rust-proof cationic electrodeposition coating composition was evaluated according to the following criteria.
A cross cut was put on the surface of the cured coating film with a cutter knife until reaching the substrate, and a salt spray test (5% saline, 35 ° C.) was performed for 1200 hours. The rust width on one side of the crosscut portion after the test was visually evaluated. As a criterion, one having a one-side rust width of 2 mm or less was accepted, and one having a one-side rust width of 2 mm or less was rejected.

Examples 2-3
A cationic electrodeposition coating composition was prepared in the same manner as in Example 1 except that the amount of the pigment settling inhibitor was changed to the amount shown in Table 2. Next, electrodeposition was applied in the same manner as in Example 1, and the same evaluation was performed.

Comparative Examples 1-3
A cationic electrodeposition coating composition was prepared in the same manner as in Example 1 except that the amount of the pigment settling inhibitor was changed to the amount shown in Table 2. Next, electrodeposition was applied in the same manner as in Example 1, and the same evaluation was performed.

Example 4
A cationic electrodeposition coating composition was prepared in the same manner as in Example 1 except that the extender pigment was changed to calcined kaolin (“SATINTON W” manufactured by BASF, oil absorption 55 ml / 100 g, average particle size 1.4 μm). Next, electrodeposition was applied in the same manner as in Example 1, and the same evaluation was performed.

Examples 5-6
A cationic electrodeposition coating composition was prepared in the same manner as in Example 4 except that the amount of the pigment settling inhibitor was changed to the amount shown in Table 3. Next, electrodeposition was applied in the same manner as in Example 4, and the same evaluation was performed.

Comparative Examples 4-6
A cationic electrodeposition coating composition was prepared in the same manner as in Example 4 except that the amount of the pigment settling inhibitor was changed to the amount shown in Table 3. Next, electrodeposition was applied in the same manner as in Example 4, and the same evaluation was performed.

Example 7
A cationic electrodeposition coating composition was prepared in the same manner as in Example 1 except that the extender pigment was changed to calcined kaolin (“Mattex” manufactured by BASF, oil absorption 70 ml / 100 g, average particle size 1.3 μm). Next, electrodeposition was applied in the same manner as in Example 1, and the same evaluation was performed.

Examples 8-9
A cationic electrodeposition coating composition was prepared in the same manner as in Example 7 except that the amount of the pigment settling inhibitor was changed to the amount shown in Table 4. Next, electrodeposition was applied in the same manner as in Example 7, and the same evaluation was performed.

Comparative Examples 7-9
A cationic electrodeposition coating composition was prepared in the same manner as in Example 7 except that the amount of the pigment settling inhibitor was changed to the amount shown in Table 4. Next, electrodeposition was applied in the same manner as in Example 7, and the same evaluation was performed.

Example 10
A cationic electrodeposition coating composition was prepared in the same manner as in Example 1 except that the extender pigment was changed to calcined kaolin (manufactured by ENGEL HARD CORPORATION, product number SATINTON 5, oil absorption 90 ml / 100 g, average particle size 0.8 μm). . Next, electrodeposition was applied in the same manner as in Example 1, and the same evaluation was performed.

Examples 11-12
A cationic electrodeposition coating composition was prepared in the same manner as in Example 10 except that the amount of the pigment settling inhibitor was changed to the amount shown in Table 5. Next, electrodeposition was applied in the same manner as in Example 10, and the same evaluation was performed.

Comparative Examples 10-12
A cationic electrodeposition coating composition was prepared in the same manner as in Example 10 except that the amount of the pigment settling inhibitor was changed to the amount shown in Table 5. Next, electrodeposition was applied in the same manner as in Example 10, and the same evaluation was performed.

  The evaluation results of the above Examples and Comparative Examples are shown in Tables 2 to 5 below.

  As shown in Tables 2 to 5, Examples 1 to 12 using the cationic electrodeposition coating composition containing 5 to 20% by mass of the pigment anti-settling agent (a) were used as a vertical surface (C surface) and a horizontal surface ( It can be seen that the film thickness difference and the gloss value difference with respect to (A surface) are small. On the other hand, in Comparative Examples 1-2, 4-5, 7-8, and 10-11 in which the amount of the pigment anti-settling agent (a) is less than 5% by mass, the difference in gloss value is more than 25, which is sufficient. It can be seen that the effect is not obtained. Further, in Comparative Examples 3 and 6 in which the amount of the pigment anti-settling agent (a) exceeds 20% by mass, the gloss difference and the film thickness difference were good, but in particular, the cationic pigment used for the preparation of the cationic electrodeposition coating composition. Since the viscosity of the paste was increased, stirring during preparation of the electrodeposition coating composition was difficult, and it was confirmed that the coating preparation workability was poor. Moreover, it was confirmed that in Comparative Examples 3, 6, 9, and 12 in which the amount of the pigment settling inhibitor (a) exceeds 20% by mass, the antirust property is inferior.

  Using the electrodeposition coating film forming method of the present invention, by applying electrodeposition to a three-dimensional object to be coated, the difference in gloss between the coating film on the horizontal surface portion and the coating film on the vertical surface portion is small, A coating film having a more uniform coating film appearance can be formed. The method of the present invention has a high utility value in an industry in which an article having a larger and complicated three-dimensional shape is applied and a high design property is required, such as the automobile coating field.

It is the schematic which shows the three-dimensional shape of the to-be-coated object (L-shaped board) which carried out the electrodeposition coating in the Example and the comparative example.

Claims (3)

A method of electrodeposition coating on a three-dimensional object to form an electrodeposition coating film,
The electrodeposition coating composition used for the electrodeposition coating is
(A) a pigment antisettling agent which is a fatty acid, a derivative of fatty acid, an amine compound, or a mixture of at least two selected from these three types, and (b) an inorganic pigment,
Including
In the electrodeposition coating composition, the content of the pigment anti-settling agent (a) is 5 to 20% by mass with respect to the total mass of the inorganic pigment (b).
Electrodeposition coating formation method.   The electrodeposition coating film forming method according to claim 1, wherein the inorganic pigment (b) includes an extender pigment having an oil absorption of 70 ml / 100 g or less.   In the electrodeposition coating film forming method for forming an electrodeposition coating film on a three-dimensional object to be coated, the difference in gloss value between the film formed on the horizontal surface part and the film formed on the vertical surface part of the object to be coated The method of forming an electrodeposition coating film according to claim 1 or 2, wherein: is 25 or less.

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