JP2015193684A - cationic electrodeposition coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cationic electrodeposition coating composition having excellent manufacturability.SOLUTION: The cationic electrodeposition coating composition comprises an amine-modified epoxy resin (a), a blocked isocyanate curing agent (b), and a solid tin curing catalyst (c) having a specified particle size distribution.

Description

  The present invention relates to a cationic electrodeposition coating composition comprising an amine-modified epoxy resin (a); a blocked isocyanate curing agent (b); and a solid tin curing catalyst (c).

  Cationic electrodeposition coating is a coating method performed by immersing an object to be coated in a cationic electrodeposition paint and applying a voltage using the object to be coated as a cathode. In this method, even a coated object having a complicated shape can be applied to the details, and can be painted automatically and continuously, so that the coated object having a large and complicated shape such as an automobile body. Widely used as an undercoating method. Cationic electrodeposition coating can impart high anticorrosion properties to the object to be coated, and therefore has an excellent protective effect on the object to be coated.

  Cationic electrodeposition paints generally include an amine-modified epoxy resin, a blocked isocyanate curing agent and a curing catalyst. Conventionally, lead compounds have been used as curing catalysts, but cationic electrodeposition paints that do not contain lead have come to be used from the viewpoint of reducing the burden on the environment. For example, tin compounds are widely used as curing catalysts in lead-free cationic electrodeposition coatings. Such tin compounds are generally solid and liquid.

  When a solid tin curing catalyst is used for the cationic electrodeposition coating, in the production process of the cationic electrodeposition coating composition, the powdered solid tin curing catalyst is dispersed using an aqueous solvent and a dispersing resin, and then a pulverizer. In many cases, the paste is made into a paste while being pulverized and mixed with a suspension in which an amine-modified epoxy resin and a blocked isocyanate curing agent are dispersed in an aqueous solvent. This is because it is difficult to disperse the powdered solid tin curing catalyst in a single step in a uniform state at a low concentration as used in the cationic electrodeposition coating composition.

  When a liquid tin curing catalyst is used for the cationic electrodeposition coating, the above-mentioned problem relating to the dispersion of the tin curing catalyst does not occur. However, the liquid tin curing catalyst may react with water used in the production process and hydrolyze. As a result, the curing catalyst activity is deactivated, and the cationic electrodeposition coating composition may not be sufficiently cured. Further, the hydrolysis may produce a water-insoluble reaction product, which may deteriorate the appearance of the coating film.

  A solid curing catalyst that is well dispersed in an aqueous solvent, which is advantageous for the production of a cationic electrodeposition coating composition, has been developed (Patent Document 1). Patent Document 1 discloses a cationic electrodeposition coating composition containing a solid curing catalyst having an average particle size of 50 to 200 nm and excellent in dispersion stability.

JP 2008-231142 A

  In the production of a cationic electrodeposition coating composition using a solid tin curing catalyst having a particle size distribution with an average particle size of submicrometer or less, the viscosity of a paste in which the solid tin curing catalyst is dispersed in an aqueous solvent and a pigment resin is increased. There was a tendency and it was not preferable from the viewpoint of manufacturing work efficiency. Conversely, in the production of a cationic electrodeposition coating composition using a solid tin curing catalyst having a large particle size distribution, the dispersibility may be inferior, and the stability of the cationic electrodeposition coating and the coating formed by the coating may be reduced. The film appearance may be inferior.

  In order to solve the above problems, the present inventors have intensively studied a cationic electrodeposition coating composition containing a solid tin curing catalyst having various particle size distributions. As a result, the solid tin curing catalyst having a predetermined particle size distribution is From the viewpoint of the production work of the electrodeposition coating composition, it was found that it exhibits good dispersibility and viscosity, and the present invention has been completed.

[1] A cationic electrodeposition coating composition comprising an amine-modified epoxy resin (a); a blocked isocyanate curing agent (b); and a solid tin curing catalyst (c), wherein the solid tin curing catalyst (c) is 0.9 μm. A cationic electrodeposition coating composition having the above D10 value and a D90 value of 209 μm or less.
[2] The cationic electrodeposition coating composition according to [1], wherein the solid tin curing catalyst (c) has a D10 value of 0.9 μm to 27.5 μm and a D90 value of 9 μm to 209 μm.
[3] The cationic electrodeposition coating composition according to [1] or [2], wherein the solid tin curing catalyst (c) has a D10 value of 0.9 μm to 11 μm and a D90 value of 9 μm to 110 μm.
[4] The method according to any one of [1] to [3], further comprising at least one component selected from a pigment, a plasticizer, a surfactant, a coating film surface smoothing agent, an antioxidant, and an ultraviolet absorber. Cationic electrodeposition coating composition.
[5] The cationic electrodeposition coating composition according to any one of [1] to [4], comprising an amine-modified epoxy resin (a); a blocked isocyanate curing agent (b); and a solid tin curing catalyst (c). A solid tin curing catalyst (c) and a pigment-dispersed resin are mixed to obtain a solid tin curing catalyst-dispersed paste; and an amine-modified epoxy resin (a) and a blocked isocyanate ( The manufacturing method including the process of mixing the binder resin emulsion obtained by mixing b) and an aqueous solvent, and the said solid tin hardening catalyst dispersion | distribution paste, and obtaining the cationic electrodeposition coating composition.
[6] A method for producing a cationic electrodeposition coating composition according to [4], comprising an amine-modified epoxy resin (a); a blocked isocyanate curing agent (b); a solid tin curing catalyst (c); and a pigment. The following steps: a step of mixing a solid tin curing catalyst (c), a pigment and a pigment dispersion resin to obtain a solid curing catalyst / pigment dispersion paste; and an amine-modified epoxy resin (a) and a blocked isocyanate (b) And a binder resin emulsion obtained by mixing an aqueous solvent and the solid tin curing catalyst / pigment dispersion paste to prepare a cationic electrodeposition coating composition, thereby preparing a solid tin curing catalyst dispersion paste A manufacturing method that does not include a process.
[7] An article having a cured electrodeposition coating film obtained by coating with the cationic electrodeposition coating composition according to any one of [1] to [4].

  The solid tin curing catalyst used in the cationic electrodeposition coating composition according to the present invention has a good viscosity and dispersibility when a paste is prepared using a pigment dispersing resin and an aqueous solvent. Preferred for the production of the composition. According to the solid tin curing catalyst according to the present invention in which the particle size distribution is controlled, it is possible to produce a cationic electrodeposition coating composition even when a solid tin curing catalyst dispersion paste is not prepared, which has a great industrial advantage. Can do. The cationic electrodeposition coating composition according to the present invention exhibits good coating stability, and the coating film exhibits a good coating film appearance. In addition, the cationic electrodeposition coating composition according to the present invention can provide a coating film exhibiting improved corrosion resistance.

Cationic electrodeposition coating composition The cationic electrodeposition coating composition of the present invention comprises an amine-modified epoxy resin (a), a blocked isocyanate curing agent (b), and a curing catalyst (c). The cationic electrodeposition coating composition of the present invention is characterized in that the contained curing catalyst is a solid tin curing catalyst having a predetermined particle size distribution. The cationic electrodeposition coating composition of the present invention may further contain other components such as a pigment, if necessary.

Amine-modified epoxy resin (a)
The amine-modified epoxy resin (a) is one type of coating film-forming resin in the cationic electrodeposition coating composition. As the amine-modified epoxy resin (a) according to the present invention, an amine-modified epoxy resin generally used in electrodeposition coating compositions can be used without any particular limitation. As the amine-modified epoxy resin (a), an amine-modified epoxy resin known to those skilled in the art and a commercially available epoxy resin obtained by amine modification can be used.

  The amine-modified epoxy resin (a) according to the present invention is preferably an amine-modified epoxy resin obtained by modifying an oxirane ring in the resin skeleton with an organic amine compound. In general, the amine-modified epoxy resin (a) is formed by ring-opening by a reaction between an oxirane ring in the starting material resin molecule and an amine such as a primary amine, secondary amine or tertiary amine and / or its acid salt. Is done. The starting material resin is typically a polyphenol polyglycidyl ether type epoxy resin which is a reaction product of a polycyclic phenol compound such as bisphenol A, bisphenol F, bisphenol S, phenol novolak, cresol novolak and epichlorohydrin. . Examples of other starting material resins include known oxazolidone ring-containing epoxy resins described in JP-A-5-306327. These epoxy resins can be obtained by the reaction of a diisocyanate compound or a bisurethane compound obtained by blocking an NCO group of a diisocyanate compound with a lower alcohol such as methanol or ethanol and epichlorohydrin.

  Before starting the oxirane ring opening reaction with amines, the above starting material resin is chain extended with bifunctional polyester polyol, polyether polyol, bisphenol, dibasic carboxylic acid, etc. It may be used as a raw material resin.

  Before the oxirane ring-opening reaction with amines, 2-ethylhexanol, nonylphenol, ethylene glycol mono-2 for some oxirane rings for the purpose of adjusting molecular weight or amine equivalent, improving heat flow, etc. -Monohydroxy compounds such as ethylhexyl ether, ethylene glycol mono n-butyl ether, propylene glycol mono-2-ethylhexyl ether may be added.

  Examples of amines that can be used for opening an oxirane ring and introducing an amino group include butylamine, octylamine, diethylamine, dibutylamine, methylbutylamine, monoethanolamine, diethanolamine, N-methylethanolamine, N- Examples include primary amines such as ethylethanolamine, triethylamine, N, N-dimethylbenzylamine, N, N-dimethylethanolamine, secondary amines, tertiary amines and / or their acid salts. Further, ketimine block primary amino group-containing secondary amine such as aminoethylethanolamine methyl isobutyl ketimine, diethylenetriamine diketimine can also be used. These amines are desirably reacted at least in an equivalent amount with respect to the oxirane ring in order to open all the oxirane rings.

  The number average molecular weight of the amine-modified epoxy resin (a) is preferably in the range of 1,000 to 5,000, and more preferably in the range of 1,500 to 3,000. When the number average molecular weight is less than 1,000, physical properties such as solvent resistance and corrosion resistance of the cured coating film may be inferior. Moreover, when a number average molecular weight exceeds 5,000, the flow property at the time of baking hardening is inferior, and the external appearance of the obtained cured electrodeposition coating film may be inferior. In the present invention, the average number molecular weight of the resin component can be measured by GPC (gel permeation chromatography), and can be calculated by a conversion value based on a polystyrene standard.

  The amine-modified epoxy resin (a) preferably has a hydroxyl value in the range of 50 to 200 mmol / 100 g. If the hydroxyl value is less than 50 mmol / 100 g, the coating film may be poorly cured. When the hydroxyl value exceeds 250 mmol / 100 g, excessive hydroxyl groups remain in the coating film after curing, and as a result, the water resistance may decrease.

  The amine-modified epoxy resin (a) preferably has an amine value of 150 mmol / 100 g or less. When the amine value exceeds 150 mmol / 100 g, excess amino groups remain in the coating film after electrodeposition curing, and as a result, the water resistance may decrease.

Block isocyanate curing agent (b)
The blocked isocyanate curing agent (b) is a kind of film-forming resin in the cationic electrodeposition coating composition, and can act as a curing agent for curing the amine-modified epoxy resin (a). The blocked isocyanate curing agent (b) according to the present invention is obtained by blocking polyisocyanate with a blocking agent. Here, the polyisocyanate compound refers to a compound having two or more isocyanate groups in one molecule. As a polyisocyanate compound, any of an aliphatic type, an alicyclic type, an aromatic type, an aromatic-aliphatic type etc. may be sufficient, for example.

  Examples of the polyisocyanate compound 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-diisocyanato Such as rucyclohexane (hydrogenated XDI), hydrogenated TDI, 2,5- or 2,6-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane (also referred to as norbornane diisocyanate). Aliphatic diisocyanates having 5 to 18 carbon atoms; aliphatic diisocyanates having an aromatic ring such as xylylene diisocyanate (XDI) and tetramethylxylylene diisocyanate (TMXDI); modified products of these diisocyanates (urethanes, carbodiimides) Uretodione, uretoimine, burette and / or isocyanurate modified product); and the like. The said polyisocyanate compound may be used independently or may use 2 or more types together.

  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 should also be used as the block isocyanate curing agent (b). Can do.

  Preferable 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 a reagent that blocks by adding to the isocyanate group of the polyisocyanate compound. The blocked isocyanate group formed by the addition of the blocking agent is stable at room temperature, but when heated above the dissociation temperature (usually 100 to 180 ° C.), the blocking agent dissociates and free isocyanate groups are regenerated. obtain.

  When low-temperature curing (160 ° C. or lower) is desired, the blocking agents include lactam-based blocking agents such as ε-caprolactam, δ-valerolactam, γ-butyrolactam, and β-propiolactam, and formaldoxime, acetoaldoxime, Oxime-based blocking agents such as acetoxime, methyl ethyl ketoxime, diacetyl monooxime and cyclohexane oxime are preferred.

Solid tin curing catalyst (c)
The solid tin curing catalyst (c) according to the present invention can promote the dissociation of the blocking agent of the blocked isocyanate curing agent (b), thereby promoting the formation of a cured coating film. The solid tin curing catalyst (c) according to the present invention can improve the crosslinking density and glass transition temperature (Tg) of the cured coating film to be formed. The solid tin curing catalyst (c) according to the present invention has a D10 value of 0.9 μm or more and a D90 value of 209 μm or less.

  As the solid tin curing catalyst (c) according to the present invention, any solid tin curing catalyst generally used for the purpose of promoting dissociation of the blocking agent from the blocked isocyanate curing agent (b) can be used without particular limitation. Examples of the solid tin curing catalyst include dibutyltin oxide (DBTO), dioctyltin oxide (DOTO), monobutyltin oxide (MBTO), monooctyltin oxide, and mixtures thereof.

  The solid tin curing catalyst (c) according to the present invention is excellent in the dissociation promoting action of the blocking agent.

  As the solid tin curing catalyst (c) according to the present invention, a tin compound prepared to have a predetermined particle size distribution can be used. For example, it can be prepared using a grinder from a tin compound prepared according to a known method or obtained commercially. Examples of such a pulverizer include a ball mill and a sand grind mill, and a sand grind mill is preferable. In the grinding step, it is preferable to use relatively hard beads such as zirconium or zircon (zirconium silicate). The beads used in the pulverization step are preferably those having a diameter of 1 mm or less. In the preparation of the solid tin curing catalyst (c) according to the present invention having a predetermined particle size distribution, a solid tin curing catalyst having an average particle diameter of 2 to 100 μm is preferably used as a raw material.

  The solid tin curing catalyst (c) according to the present invention may be prepared so as to have a predetermined particle size distribution in the production process of the cationic electrodeposition coating composition according to the present invention. For example, a process of preparing a solid tin curing catalyst dispersion paste by mixing a solid tin curing catalyst with a pigment dispersion resin or an aqueous solvent, or mixing a pigment and solid tin curing catalyst with a pigment dispersion resin or an aqueous solvent to form a solid tin In the step of preparing the curing catalyst / pigment dispersion paste, the solid tin curing catalyst is pulverized and dispersed using a pulverizer to prepare a paste containing the solid tin curing catalyst (c) having a predetermined particle size distribution. Also good.

  In the present specification, the D90 value of the solid tin curing catalyst which is a particle group means a value of 90% cumulative particle size on a volume basis, and the D10 value of the solid tin curing catalyst which is a particle group is 10% cumulative particle on a volume basis. It means the value of diameter. In the present specification, the D90 value and the D10 value are values (volume average particle diameter) measured by a laser light scattering method. For example, a laser scattering diffraction particle size distribution analyzer LS 13 320 (manufactured by Beckman Coulter, Inc.) Measured by In the present invention, when a dispersion paste is prepared using a solid tin curing catalyst composed of particles having a D10 value of less than 0.9 μm, the viscosity increases, which is preferable from the viewpoint of the production work of the cationic electrodeposition coating composition. There may not be. Further, when a dispersion paste is prepared using a solid tin curing catalyst composed of particles having a D90 value exceeding 209 μm, the dispersibility tends to be inferior, which may be undesirable from the viewpoint of the appearance of the formed coating film.

  The solid tin curing catalyst (c) according to the present invention is preferably used in an amount of 0.1 to 6 parts by mass with respect to 100 parts by mass of the resin solid content contained in the cationic electrodeposition coating composition. When used in an amount of less than 0.1 parts by mass with respect to 100 parts by mass of the resin solid content of the cationic electrodeposition coating composition, the resulting coating film may not be sufficiently cured. Moreover, when using it in the quantity exceeding 6 mass parts with respect to 100 mass parts of resin solid content of a cationic electrodeposition coating composition, there exists a possibility that the catalyst effect corresponding to addition amount cannot be acquired. The “resin solid content” in the present specification means the resin solid content in the coating composition containing the amine-modified epoxy resin (a), the blocked isocyanate curing agent (b), and the pigment dispersion resin described below when present. To do.

  In one embodiment of the present invention, the solid tin curing catalyst (c) according to the present invention has a D10 value of 0.9 μm or more and a D90 value of 209 μm or less. The D10 value is preferably 0.9 μm to 27.5 μm, the D90 value is 9 to 209 μm, more preferably the D10 value is 0.9 μm to 11 μm, and the D90 value is 9 to 110 μm. In either case, when the D10 value is less than 0.9 μm, the interaction between the solid tin cured catalyst particles becomes strong, the viscosity of the solid tin cured catalyst dispersed paste increases, and the working efficiency may be greatly impaired. On the other hand, when the D90 value exceeds 209 μm, the dispersibility is impaired and undispersed coarse particles remain, which may impair the appearance of the cured electrodeposition coating film.

  In this specification, D90 / D10 is an index indicating the width of the particle size distribution, and this value is larger than 1. A larger D90 / D10 value indicates a wider particle size distribution, and a smaller value indicates a smaller particle size distribution width. In one embodiment of the present invention, the solid tin curing catalyst (c) according to the present invention has a D90 / D10 of 1 to 200, preferably 1 to 150, more preferably 1 to 20. When the D90 / D10 value exceeds 200, it means that dispersibility is impaired from the viewpoint of particle size distribution. When the solid tin curing catalyst is contained, care must be taken because undispersed coarse particles remain in the system and the appearance of the cured electrodeposition coating film may be impaired.

  In the present specification, the “solid” used in connection with the solid tin curing catalyst may be in a solid state, that is, in a state in which the shape is maintained under a usual environment (for example, 50 ° C.). “Solid” includes both crystalline and amorphous states (so-called amorphous).

Pigment The cationic electrodeposition coating composition of the present invention may contain a pigment. As the pigment, those usually used for paints can be used without particular limitation. Examples of such pigments include colored pigments such as carbon black, titanium dioxide, and graphite; extender pigments such as kaolin, aluminum silicate (clay), talc, and barium sulfate; aluminum phosphomolybdate, lead silicate, lead sulfate, and zinc. Examples thereof include rust preventive pigments such as chromate and strontium chromate. Of these, titanium dioxide, aluminum silicate (clay), and aluminum phosphomolybdate are preferably used. In particular, titanium dioxide is preferable for a cationic electrodeposition coating composition because it has high concealability as a color pigment and is inexpensive. The above pigments may be used alone or in combination of two or more according to the purpose.

  The pigment is used in an amount of 5 to 50 parts by mass with respect to 100 parts by mass of the resin solid content contained in the cationic electrodeposition coating composition.

Other Components The cationic electrodeposition coating composition of the present invention can contain conventional coating additives such as a plasticizer, a surfactant, a coating film surface smoothing agent, an antioxidant and an ultraviolet absorber. In addition, resin components such as cationic acrylic resins and crosslinked resin particles may be included as necessary. These other components can be used without particular limitation as long as they are used in the cationic electrodeposition coating composition.

Pigment Dispersion Paste The pigment may be preliminarily dispersed in an aqueous solvent at a high concentration together with the following pigment dispersion resin to form a paste, and the paste may be used for producing an electrodeposition coating composition. This is because it is difficult to disperse the pigment in a single step in a uniform state at a low concentration as used in an electrodeposition coating composition because the pigment is in powder form. In the present specification, such a paste is referred to as a “pigment dispersion paste”.

  The pigment dispersion paste is prepared by dispersing a pigment together with a pigment dispersion resin in an aqueous solvent. The pigment dispersion resin can be used without particular limitation as long as it is a resin used for dispersing a powdery pigment or the like in a cationic electrodeposition coating. As the pigment dispersion resin, for example, a cationic polymer such as 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 used. As the aqueous solvent, ion-exchanged water or water containing a small amount of alcohol is used. The pigment dispersion paste generally contains a pigment dispersion resin in a solid content ratio of 1 to 20 parts by mass and a pigment in a solid content ratio of 1 to 35 parts by mass. This pigment dispersion paste is mixed with the pigment dispersion resin and the pigment, and pulverized using a normal pulverizer such as a ball mill or a sand grind mill until the pigment particle size in the mixture reaches a predetermined uniform particle size. And can be prepared by dispersing.

Solid tin curing catalyst-dispersed paste The solid tin curing catalyst (c) according to the present invention does not necessarily have to be dispersed in an aqueous solvent at a high concentration in advance together with the pigment-dispersed resin to form a paste. In the form, in the production process of the cationic electrodeposition coating composition, the solid tin curing catalyst can be used in the form of a paste by dispersing it in an aqueous solvent together with the pigment dispersion resin. In this specification, the paste in which the solid tin curing catalyst is dispersed is referred to as “solid tin curing catalyst dispersed paste”.

  The solid tin curing catalyst dispersion paste is generally used in an amount of 20 to 80 parts by mass of the pigment dispersion resin and 20 to 80 parts by mass of the solid tin curing catalyst with respect to 100 parts by mass of the solid content of the paint paste. In one embodiment of the present invention, the solid tin curing catalyst is pulverized in advance using a normal pulverizer such as a ball mill or a sand grind mill before preparing the solid tin curing catalyst dispersion paste, and a predetermined particle size distribution is obtained. The solid tin curing catalyst (c) may be used. In this embodiment, the time for preparing the solid tin curing catalyst-dispersed paste having a predetermined particle size distribution depends on the conditions such as the type and particle size distribution of the solid tin curing catalyst and beads used for the paste preparation, and the type of grinding device. May increase or decrease. The particle size distribution of the solid tin curing catalyst is measured by, for example, a laser scattering diffraction particle size distribution analyzer LS 13 320 (manufactured by Beckman Coulter, Inc.). In the present invention, when forming a solid tin curing catalyst-dispersed paste, the above-mentioned pigment dispersion resin and the solid tin curing catalyst (c) according to the present invention are mixed until the powdery component in the mixture is uniformly dispersed. It can be prepared by dispersing using a normal dispersing apparatus such as a ball mill or a sand grind mill. According to the solid tin curing catalyst according to the present invention, since the solid tin curing catalyst dispersion paste to be formed exhibits a good viscosity, the time required for forming the paste can be shortened. Is advantageous. Moreover, according to the solid tin curing catalyst according to the present invention, the cationic electrodeposition coating composition according to the present invention can be prepared without preparing the solid tin curing catalyst dispersion paste.

  In one embodiment of the present invention, the solid tin curing catalyst is pulverized using a normal pulverizer such as a ball mill or a sand grind mill when preparing the solid tin curing catalyst dispersion paste, and has a predetermined particle size distribution. A solid tin curing catalyst (c) may be used. In this embodiment, the time for preparing the solid tin curing catalyst dispersed paste having a predetermined particle size distribution is the type and particle size distribution of the solid tin curing catalyst and beads used for the paste preparation, or the pigment dispersion resin, the aqueous solvent and the grinding device. It can be increased or decreased depending on conditions such as the type. The particle size distribution of the solid tin curing catalyst can be obtained by measuring a powdered solid tin curing catalyst obtained by taking a partial sample of the paste being prepared and dissolving the resin. Once the conditions for preparing the paste containing the solid tin curing catalyst having the predetermined particle size distribution are determined, the solid tin curing catalyst (c) having the predetermined particle size distribution is not required without measuring the particle size distribution of the solid tin curing catalyst. It is also possible to prepare a solid tin curing catalyst dispersion paste containing.

Solid tin curing catalyst / pigment-dispersed paste The pigment and the solid tin curing catalyst (c) are preliminarily dispersed in an aqueous solvent at a high concentration together with the pigment-dispersing resin, and the paste is formed into a cationic electrodeposition coating composition. You may use for manufacture. In this specification, such a paste is referred to as “solid tin curing catalyst / pigment dispersion paste”.

  The solid tin curing catalyst / pigment dispersion paste uses 1 to 20 parts by mass of the pigment dispersion resin, 0.1 to 4 parts by mass of the solid tin curing catalyst, and 1 to 35 parts by mass of the pigment. In one embodiment of the present invention, the solid tin curing catalyst / pigment dispersion paste is a mixture of the pigment dispersion resin, the pigment, and the solid tin curing catalyst (c) according to the present invention, and the powdery component in the mixture is mixed. Until it is uniformly dispersed, it can be prepared by dispersing using a normal dispersing device such as a ball mill or a sand grind mill. In another embodiment of the present invention, the above-mentioned pigment dispersion resin, pigment and solid tin curing catalyst are mixed, pulverized and dispersed using a normal pulverizer such as a ball mill or a sand grind mill, and the solid tin according to the present invention is mixed. A solid tin curing catalyst / pigment dispersion paste containing the curing catalyst (c) may be prepared.

Preparation of cationic electrodeposition coating composition The cationic electrodeposition coating composition of the present invention comprises the amine-modified epoxy resin (a), the blocked isocyanate curing agent (b), and the solid tin curing catalyst (c). In one embodiment, the cationic electrodeposition coating composition of the present invention comprises an amine-modified epoxy resin (a), a blocked isocyanate curing agent (b), and a solid tin curing catalyst (c), and optionally a pigment dispersion paste. Can be prepared by mixing at a predetermined ratio.

  In one embodiment of the present invention, the solid tin curing catalyst (c) according to the present invention exhibits a good viscosity and dispersibility in the dispersion paste, and thus is added in various ways in the production of the cationic electrodeposition coating composition. Can be mixed. For example, a suspension in which an amine-modified epoxy resin (a) and a blocked isocyanate curing agent (b) are dispersed in an aqueous solvent (hereinafter also referred to as “binder resin emulsion”) and a powdered solid tin curing catalyst are mixed. Thus, the cationic electrodeposition coating composition according to the present invention may be produced. In the present specification, the binder resin emulsion means a suspension containing an amine-modified epoxy resin (a) and a blocked isocyanate curing agent (b). The binder resin emulsion according to the present invention is preferably an amine-modified epoxy resin (a) and a blocked isocyanate curing agent (b) in a ratio of 90:10 to 50:50 (amine-modified epoxy resin: blocked isocyanate curing agent). Including.

  In one embodiment of the present invention, the present invention comprises an amine-modified epoxy resin (a); a blocked isocyanate curing agent (b); and a solid tin curing catalyst (c), optionally pigments, plasticizers, surfactants. A method for producing a cationic electrodeposition coating composition, further comprising at least one component selected from a coating surface smoothing agent, an antioxidant and an ultraviolet absorber, and having a predetermined particle size distribution A step of mixing the catalyst (c) with a pigment dispersion resin to obtain a solid tin curing catalyst dispersion paste, and a binder resin comprising the solid tin curing catalyst dispersion paste, the amine-modified epoxy resin (a) and the blocked isocyanate (b) Provided is a production method comprising a step of mixing with an emulsion. In one embodiment, when the cationic electrodeposition coating composition of the present invention contains a pigment, a pigment dispersion paste containing a pigment and a pigment dispersion resin, a solid tin curing catalyst dispersion paste, and a binder resin emulsion are mixed. The cationic electrodeposition coating composition of the present invention may be produced. In other embodiments, the pigment dispersion paste and the solid tin curing catalyst dispersion paste may be mixed and mixed with the mixed dispersion paste and the binder resin emulsion to produce the cationic electrodeposition coating composition of the present invention.

  In another aspect of the present invention, the present invention comprises an amine-modified epoxy resin (a); a blocked isocyanate curing agent (b); and a solid tin curing catalyst (c), optionally with pigments, plasticizers, surfactants. A method for producing a cationic electrodeposition coating composition, further comprising at least one component selected from a coating surface smoothing agent, an antioxidant and an ultraviolet absorber, and having a predetermined particle size distribution A step of mixing a catalyst (c), a pigment, and a pigment dispersion resin to obtain a solid tin curing catalyst / pigment dispersion paste, and the solid tin curing catalyst / pigment dispersion paste, the amine-modified epoxy resin (a), and a blocked isocyanate The manufacturing method including the process of mixing with the binder resin emulsion containing (b) is provided. In one embodiment, the manufacturing method does not include a step of preparing a solid tin curing catalyst dispersion paste.

  In one embodiment of the present invention, the cationic electrodeposition coating composition according to the present invention comprises a solid tin curing catalyst mixed with a pigment resin and an aqueous solvent and pulverized, and the solid tin according to the present invention having a predetermined particle size distribution. A step of preparing a solid tin curing catalyst dispersion paste containing a curing catalyst (c), and mixing the solid tin curing catalyst dispersion paste with a binder resin emulsion containing an amine-modified epoxy resin (a) and a blocked isocyanate (b) You may manufacture by doing.

  In the cationic electrodeposition coating composition of the present invention, the solid content concentration is preferably adjusted to be in the range of 15 to 25% by mass. The solid content concentration can be adjusted using an aqueous solvent. The aqueous solvent can be used without particular limitation as long as it is used in the cationic electrodeposition coating composition. Examples of the aqueous solvent include ion exchange water and pure water. The aqueous solvent may contain a small amount of alcohol as required. The aqueous solvent may contain a neutralizing agent in order to improve the dispersibility of the amine-modified epoxy resin (a). Examples of the neutralizing agent include inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid and sulfamic acid or organic acids such as formic acid, acetic acid, lactic acid and acetylglycine.

  The cationic electrodeposition coating composition of the present invention is an organic solvent usually contained in the coating composition, such as ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monoethyl hexyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, Propylene glycol monophenyl ether, methyl isobutyl ketone (hereinafter referred to as “MIBK”) and the like may be used as necessary.

Formation of cured electrodeposition coating film A cured electrodeposition coating film can be obtained by electrodeposition-coating and heat-curing the cationic electrodeposition coating composition of the present invention. Cationic electrodeposition coating uses a conductive base material to be coated as a cathode, a cathode (cathode electrode) terminal is connected to the material to be coated, and the bath temperature of the above-mentioned cationic electrodeposition coating composition is 15 to 35 ° C. Under the condition of a load voltage of 100 to 400 V, generally, a coating film having an amount of a dry film thickness of 13 to 20 μm is electrodeposited. Then, a cured electrodeposition coating film can be obtained by baking at 140 to 200 ° C., preferably 160 to 180 ° C. for 10 to 30 minutes.

  The object to be coated with the cured electrodeposition coating film can be used without particular limitation as long as it is a conductive base material capable of electrodeposition coating. Examples of such a substrate include metals (for example, iron, steel, copper, aluminum, magnesium, tin, zinc, and the like and alloys containing these metals), iron plates, steel plates, aluminum plates, and surface treatments (for example, , Chemical conversion treatment using phosphate, zirconium salt and the like, and molded products thereof.

  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 amine-modified epoxy resin (a) 2,4- / 2,6-tolylene diisocyanate (mass ratio: 80/80) was placed in a flask equipped with a stirrer, cooling tube, nitrogen introduction tube, thermometer and dropping funnel. 20) 92 parts and 0.5 parts of dibutyltin dilaurate were weighed, and 21 parts of methanol were added dropwise from a dropping funnel over 30 minutes while stirring and nitrogen bubbling. The temperature of the mixture was raised from room temperature to 60 ° C. due to heat generation. Thereafter, the reaction was continued for 30 minutes, and then 57 parts of ethylene glycol mono-2-ethylhexyl ether was added dropwise from the dropping funnel over 30 minutes. The temperature of the mixture was raised to 60 ° C. due to heat generation. After the reaction was continued for 60 minutes, 42 parts of a bisphenol A-propylene oxide (6 mol) adduct (Newpol BPE60, Sanyo Chemical Industries) was added. The temperature of the mixture was raised to 60 ° C. due to heat generation, and the reaction was continued until the isocyanate group disappeared while measuring the IR spectrum.

  Subsequently, 365 parts of bisphenol A type epoxy resin (liquid epoxy-P, Dow Chemical Japan) having an epoxy equivalent of 188 was added to the above mixture and dissolved uniformly, and then heated to 125 ° C. Next, 1.0 part of benzyldimethylamine was added to carry out an oxazolidone ring formation reaction by a demethanol reaction. The reaction continued until an epoxy equivalent weight of 410 was reached.

  Next, 87 parts of bisphenol A was added and reacted at 120 ° C. and allowed to cool. The epoxy equivalent of the reaction mixture was 1190. To the reaction mixture, 11 parts of diethanolamine, 24 parts of N-ethylethanolamine and 25 parts of aminoethylethanolamine ketimine (79% MIBK solution) were added and reacted at 110 ° C. for 2 hours. Then, it diluted with MIBK until it became non-volatile content 80%, and the amine modified epoxy resin (a) (resin solid content 77%) was obtained.

Production Example 2 Preparation of Blocked Isocyanate Curing Agent (b) 1250 parts of diphenylmethane diisocyanate and 266.4 parts of MIBK were charged into a reaction vessel and heated to 80 ° C., and then 2.5 parts of dibutyltin dilaurate was added. A solution prepared by dissolving 226 parts of ε-caprolactam in 944 parts of butyl cellosolve was added dropwise at 80 ° C. over 2 hours. Furthermore, after heating at 100 degreeC for 4 hours, in the measurement of IR spectrum, it confirmed that absorption based on an isocyanate (NDO) group disappeared, and after standing to cool, MIBK336.1 part was added, blocked isocyanate hardening | curing agent (b )

Production Example 3 Preparation of Pigment Dispersing Resin 222.0 parts of isophorone diisocyanate (hereinafter referred to as “IPDI”) was weighed in a reaction vessel equipped with a stirrer, a cooling tube, a nitrogen introduction tube and a thermometer, and MIBK 39.1. Then, 0.2 parts of dibutyltin dilaurate was added to the diluted product. After the temperature of the mixture was raised to 50 ° C., 131.5 parts of 2-ethylhexanol was added dropwise under stirring in a dry nitrogen atmosphere over 2 hours. The reaction temperature was maintained at 50 ° C. 2-ethylhexanol half-blocked IPDI (resin solid content 90.0%) was obtained.

  Next, 87.2 parts of dimethylethanolamine, 117.6 parts of a 75% aqueous lactic acid solution and 39.2 parts of ethylene glycol monobutyl ether are added to the reaction vessel in this order, and stirred at 65 ° C. for about half an hour to add the quaternizing agent. Prepared.

  Next, 710.0 parts of EPON (EPON) 829 (bisphenol A type epoxy resin manufactured by Shell Chemical Company, epoxy equivalent: 193 to 203) and 289.6 parts of bisphenol A were charged into a reaction vessel, By heating to ˜160 ° C., an initial exothermic reaction occurred. The reaction mixture was reacted at 150-160 ° C. for about 1 hour and then cooled to 120 ° C. To the reaction mixture, 498.8 parts of previously prepared 2-ethylhexanol half-blocked IPDI (MIBK solution) was added.

  While maintaining the reaction mixture at 110-120 ° C. for about 1 hour, 463.4 parts of ethylene glycol monobutyl ether was added. The mixture was cooled to 85-95 ° C. and homogenized, and 196.7 parts of the previously prepared quaternizing agent was added. While maintaining the reaction mixture at 85 to 95 ° C, the reaction was continued until the acid value became 1. 200 parts of deionized water was added to the reaction mixture, and quaternization was completed in the epoxy-bisphenol A resin to obtain a resin for pigment dispersion having a quaternary ammonium salt portion (resin solid content 30%).

Production Example 5 Preparation of Solid Tin Curing Catalyst (c-1) Dibutyltin dioxide (DBTO) (trade name: Di Butyl Tin Oxide, average particle size 57.6 μm, manufactured by Maharashtra) was used. 10 parts by weight of DBTO and 8 parts by weight of 10% butyl cellosolve diluted water were put into a sand grind mill (table batch type SG mill, Daihei System Co., Ltd.). Into this sand grind mill, zirconia beads having a diameter of 0.8 mm (YTZ, Tosoh Corporation) were put and pulverized for 1 hour. D10 of the obtained solid tin curing catalyst (c-1) was 3.5 μm, and D90 was 25.5 μm. In the production examples of the present specification, D10 and D90 are values (volume average particle diameters) measured by a laser light scattering method using a laser scattering diffraction particle size distribution analyzer LS 13 320 (manufactured by Beckman Coulter, Inc.). is there.

Production Example 6 Preparation of Solid Tin Curing Catalyst (c-2) Dibutyltin Dioxide (DBTO) (trade name: PC-4220, average particle size 72.1 μm, manufactured by Nanjing Agricultural Corporation) was used, and the pulverization time was 30 minutes. Except for this, a solid tin curing catalyst was prepared in the same manner as in Production Example 5. D10 of the obtained solid tin curing catalyst (c-2) was 2.1 μm, and D90 was 16.0 μm.

Production Example 7 Preparation of Solid Tin Curing Catalyst (c-3) Dibutyltin Dioxide (DBTO) (trade name: PC-4220, average particle size 72.1 μm, manufactured by Nitto Kasei Co., Ltd.) was used, and the grinding time was 10 minutes. Except for, a solid tin curing catalyst was prepared in the same manner as in Production Example 5. D10 of the obtained solid tin curing catalyst (c-3) was 5.8 μm, and D90 was 116.2 μm.

Production Example 8 Preparation of Solid Tin Curing Catalyst (c-4) Dibutyltin Dioxide (DBTO) (trade name: Di Butyl Tin Oxide, average particle size 57.6 μm, manufactured by Maharashtra) and the grinding time was 30 minutes Except for, a solid tin curing catalyst was prepared in the same manner as in Production Example 5. D10 of the obtained solid tin curing catalyst (c-4) was 1.2 μm, and D90 was 140.0 μm.

Production Example 9 Preparation of solid tin curing catalyst (c-5) Dibutyltin dioxide (DBTO) (trade name: PC-4220, average particle size 72.1 μm, manufactured by Nanjing Agricultural Corporation) was used in the same manner as in Production Example 5. A solid tin curing catalyst was prepared. D10 of the obtained solid tin curing catalyst (c-5) was 0.3 μm, and D90 was 9.4 μm.

Production Example 10 Preparation of Solid Tin Curing Catalyst (c-6) Dibutyltin Dioxide (DBTO) (trade name: Di Butyl Tin Oxide, average particle size 57.6 μm, manufactured by Maharashtra) and pulverization time was 10 minutes Except for, a solid tin curing catalyst was prepared in the same manner as in Production Example 5. D10 of the obtained solid tin curing catalyst (c-6) was 0.1 μm, and D90 was 211.6 μm.

Production Example 11 Preparation of Solid Tin Curing Catalyst (c-7) Dioctyltin dioxide (DOTO) (trade name: Di Octyl Tin Oxide, average particle size 342.1 μm, manufactured by Maharashtra) was used. 10 parts by weight of DOTO and 8 parts by weight of 10% butyl cellosolv diluted water were put in a sand grind mill (table batch type SG mill, Ohira System Co., Ltd.). Into this grind mill, zirconia beads having a diameter of 0.8 mm (YTZ, Tosoh Corporation) were put and ground for 1 hour. D10 of the obtained solid tin curing catalyst (c-7) was 10.1 μm, and D90 was 154.1 μm.

Production Example 12 Preparation of Solid Tin Curing Catalyst (c-8) Dioctyltin dioxide (DOTO) (trade name: Axion CS 2855, average particle size 152.7 μm, manufactured by Chemtura) was used and the pulverization time was 10 minutes. Except for, a solid tin curing catalyst was prepared in the same manner as in Production Example 11. D10 of the obtained solid tin curing catalyst (c-8) was 8.2 μm, and D90 was 100.3 μm.

Production Example 13 Preparation of Solid Tin Curing Catalyst (c-9) Dioctyltin dioxide (DOTO) (trade name: Axion CS 2855, average particle size 152.7 μm, manufactured by Chemtura) was used and the pulverization time was 30 minutes. Except for, a solid tin curing catalyst was prepared in the same manner as in Production Example 11. D10 of the obtained solid tin curing catalyst (c-9) was 1.8 μm, and D90 was 9.9 μm.

Production Example 14 Preparation of Solid Tin Curing Catalyst (c-10) Using Dioctyltin Dioxide (DOTO) (trade name: Axion CS 2855, average particle size 152.7 μm, manufactured by Chemtura), in the same manner as in Production Example 11, A solid tin cure catalyst was prepared. D10 of the obtained solid tin curing catalyst (c-10) was 1.6 μm, and D90 was 12.1 μm.

Production Example 15 Preparation of Solid Tin Curing Catalyst (c-11) Dioctyltin dioxide (DOTO) (trade name: Di Octyl Tin Oxide, average particle size 342.1 μm, manufactured by Maharashtra) was used for a pulverization time of 30 minutes. Except for this, a solid tin curing catalyst was prepared in the same manner as in Production Example 11. D10 of the obtained solid tin curing catalyst (c-11) was 19.7 μm, and D90 was 224.9 μm.

Production Example 16 Preparation of Solid Tin Curing Catalyst (c-12) Dioctyltin dioxide (DOTO) (trade name: Di Octyl Tin Oxide, average particle size 342.1 μm, manufactured by Maharashtra) was used for 10 minutes. Except for this, a solid tin curing catalyst was prepared in the same manner as in Production Example 11. D10 of the obtained solid tin curing catalyst (c-12) was 10.0 μm, and D90 was 962.2 μm.

Production Example 17 Preparation of Solid Tin Curing Catalyst (c-13) The solid tin curing catalyst (c-8) prepared in Production Example 12 was sieved with a 100-mesh sieve device (aperture: 150 μm, Iida Seisakusho Co., Ltd.). did. D10 of the obtained solid tin curing catalyst (c-13) was 1.7 μm, and D90 was 19.4 μm.

Production Example 18 Preparation of Solid Tin Curing Catalyst (c-14) The solid tin curing catalyst (c-8) prepared in Production Example 12 was sieved with a 150 mesh sieve device (aperture: 100 μm, Iida Seisakusho Co., Ltd.). did. D10 of the obtained solid tin curing catalyst (c-14) was 1.9 μm, and D90 was 14.3 μm.

Production Example 19 Preparation of Solid Tin Curing Catalyst (c-15) The solid tin curing catalyst (c-8) prepared in Production Example 12 was sieved with a 200-mesh sieve device (aperture: 75 μm, Iida Manufacturing Co., Ltd.). did. D10 of the obtained solid tin curing catalyst (c-15) was 1.7 μm, and D90 was 11.6 μm.

Production Example 20 Preparation of Solid Tin Curing Catalyst Dispersion Paste (1 ) 100 parts of each solid tin curing catalyst (c-1 to c-6) prepared in Production Examples 5 to 10 and 100 parts of pigment dispersion resin prepared in Production Example 3 (Solid content 30 parts) and ion-exchanged water 32.1 parts are put in a sand grind mill (table batch type SG mill, Daihei System Co., Ltd.) and dispersed, and the solid tin curing catalyst dispersion paste is added to each solid tin curing catalyst. Prepared for (c-1 to c-6).

Production Example 21 Preparation of Solid Tin Curing Catalyst Dispersion Paste (2 ) 100 parts of each solid tin curing catalyst (c-7 to c-12) prepared in Production Examples 11 to 16, pigment dispersed resin 133 prepared in Production Example 3. 3 parts (solid content 40 parts) and 23.5 parts of ion-exchanged water are put in a sand grind mill (table batch type SG mill, Daihei System Co., Ltd.) and dispersed, and the solid tin curing catalyst dispersion paste is added to each solid tin. Prepared for the curing catalyst (c-7 to c-12).

Production Example 22 Preparation of Pigment Dispersion Paste (1) 118 parts of pigment dispersion resin prepared in Production Example 3 (solid content 31.5 parts), 47 parts of carbon and titanium oxide (color pigment), 53 parts of kaolin (extreme pigment) Each of the solid tin curing catalyst dispersion pastes 9.1 parts (solid content 5.3 parts) prepared in Production Example 20 and 33 parts of ion-exchanged water were mixed with a sand grind mill (table batch type SG mill, Ohira System Co., Ltd.). The pigment dispersion paste was prepared for each solid tin curing catalyst (c-1 to c-6).

Production Example 23 Preparation of Pigment Dispersion Paste (2) 103.6 parts of pigment dispersion resin prepared in Production Example 3 (solid content: 36.2 parts), 57 parts of carbon and titanium oxide (color pigment), kaolin (external pigment) 43 parts, 13.7 parts of each solid tin curing catalyst dispersion paste prepared in Production Example 21 (solid content 10.5 parts), and 39 parts of ion-exchanged water were added to a sand grind mill (table batch type SG mill, Ohira Corporation). The pigment dispersion paste was prepared for each solid tin curing catalyst (c-7 to c-12).

Production Example 24 Preparation of Solid Tin Curing Catalyst / Pigment Dispersion Paste (1) 110.6 parts of pigment dispersion resin prepared in Production Example 3 (solid content 39.2 parts), 57 parts of carbon and titanium oxide (color pigment), Solid tin curing catalyst (c-7, c-8, c-11 and c-13 to c-15) 7.5 prepared in 43 parts of kaolin (extreme pigment), Production Examples 11, 12, 15 and 17-19 Parts (solid content: 7.5 parts) and ion-exchanged water (40.4 parts) are put in a sand grind mill (table batch type SG mill, Daihei System Co., Ltd.) and dispersed to obtain a solid tin curing catalyst / pigment dispersion paste. Prepared for each solid tin cure catalyst (c-7, c-8, c-11 and c-13 to c-15).

Production Example 25 Preparation of Binder Resin Emulsion (1) 350 g (solid content) of an amine-modified epoxy resin (a) and 150 g (solid content) of a blocked isocyanate curing agent (b) are mixed, and ethylene glycol mono-2-ethylhexyl ether is mixed. It added so that it might become 3% (15g) with respect to solid content. Next, glacial acetic acid is neutralized to a neutralization rate of 40.5%, ion-exchanged water is added to slowly dilute, and then methyl isobutyl is reduced under reduced pressure so that the solid content is 36.0% or less. The ketone was removed to obtain a binder resin emulsion (1).

Production Example 26 Preparation of Binder Resin Emulsion (2) 350 g (solid content) of an amine-modified epoxy resin (a) and 150 g (solid content) of a blocked isocyanate curing agent (b) are mixed, and ethylene glycol mono-2-ethylhexyl ether is mixed. It added so that it might become 3% (15g) with respect to solid content. Next, glacial acetic acid is neutralized to a neutralization rate of 40.5%, ion-exchanged water is added to slowly dilute, and then methyl isobutyl is reduced under reduced pressure so that the solid content is 36.0% or less. The ketone was removed to obtain a binder resin emulsion (2).

Production Example 27 Preparation of Binder Resin Emulsion (3) 350 g (solid content) of an amine-modified epoxy resin (a) and 150 g (solid content) of a blocked isocyanate curing agent (b) are mixed, and ethylene glycol mono-2-ethylhexyl ether is mixed. It added so that it might become 3% (15g) with respect to solid content. Next, glacial acetic acid is neutralized to a neutralization rate of 40.5%, ion-exchanged water is added to slowly dilute, and then methyl isobutyl is reduced under reduced pressure so that the solid content is 36.0% or less. The ketone was removed to obtain a binder resin emulsion (3).

Preparation of cationic electrodeposition coating composition
Examples 1-4 and Comparative Examples 1-2
250 parts of binder resin emulsion (1) obtained in Production Example 25 (100 parts of solid content), 63.5 parts of each pigment dispersion paste (1) obtained in Production Example 22 (33 parts of solid content), and ions 259 parts of exchange water was mixed to obtain a cationic electrodeposition coating composition having a coating solid content of 20% by mass for each solid tin curing catalyst (c-1 to c-6). Cationic electrodeposition coating compositions containing solid tin curing catalysts c-1 to c-4 were used as Examples 1 to 4, respectively, and cationic electrodeposition coating compositions containing solid tin curing catalysts c-5 to c-6 were compared. It was set as Examples 1-2. The pigment concentration of the cationic electrodeposition coating composition was 5% by mass. The content of the solid tin curing catalyst relative to 100 parts by mass of the resin solid content of the cationic electrodeposition coating composition was 1.33 parts by mass. The solid content of the paint can be obtained as a percentage of the mass of the residue after heating at 105 ° C. for 180 minutes (based on JIS K5601).

Examples 5-8 and Comparative Examples 3-4
263 parts of binder resin emulsion (2) obtained in Production Example 26 (100 parts of solid content), 34.3 parts of each pigment dispersion paste (2) obtained in Production Example 23 (19.2 parts of solid content), And 229 parts of ion-exchanged water were mixed to obtain a cationic electrodeposition coating composition having a coating solid content of 20% by mass for each solid tin curing catalyst (c-7 to c-12). Cationic electrodeposition coating compositions containing solid tin curing catalysts c-7 to c-10 were used as Examples 5 to 8, respectively, and cationic electrodeposition coating compositions containing solid tin curing catalysts c-11 to c-12 were compared. It was set as Examples 3-4. The pigment concentration of the cationic electrodeposition coating composition was 3.3% by mass. Moreover, content of the solid tin hardening catalyst with respect to 100 mass parts of resin solid content of a cationic electrodeposition coating composition was 1.75 mass parts.

Examples 9-12 and Comparative Examples 5-6
263 parts (solid content 100 parts) of the binder resin emulsion (3) obtained in Production Example 27 and 34.3 parts (solid content 19) of each solid tin curing catalyst / pigment dispersion paste (1) obtained in Production Example 24 2 parts) and 229 parts of ion-exchanged water are mixed to form a cationic electrodeposition coating composition having a coating solid content of 20% by mass for each solid tin curing catalyst (c-7, c-8, c-11 and c- 13 to c-15). Cationic electrodeposition coating compositions containing solid tin curing catalysts c-8 and c-13 to c-15 were used as Examples 9 to 12, respectively, and cationic electrodeposition coating compositions containing solid tin curing catalysts c-7 and c-11 were used. The products were designated as Comparative Examples 5 and 6, respectively. The pigment concentration of the cationic electrodeposition coating composition was 3.3% by mass. Moreover, content of the solid tin hardening catalyst with respect to 100 mass parts of resin solid content of a cationic electrodeposition coating composition was 1.75 mass parts.

  About the solid tin curing catalyst dispersion paste, the pigment dispersion paste or the solid tin curing catalyst / pigment dispersion paste used for the preparation of the cationic electrodeposition coating composition and the cationic electrodeposition coating composition obtained by the above examples and comparative examples, An evaluation test was conducted.

Viscosity The viscosity of 200 g of the solid tin curing catalyst dispersion paste used in each Example and each Comparative Example was measured and evaluated at 35 ° C. using a Stormer viscometer (Eihiro Seiki Manufacturing Company).

The evaluation criteria for the viscosity of the solid tin curing catalyst dispersion paste or solid tin curing catalyst / pigment dispersion paste used in Examples 1 to 12 and Comparative Examples 1 to 4 are as follows:
○: ≦ 60 KU (Krebs unit);
Δ: 61-64 KU;
×: ≧ 65 KU.

Dispersion particle size 5 g of the pigment dispersion paste used in each example and each comparative example was diluted with 5 g of butyl cellosolve, and the dilution was evaluated for the dispersibility of the solid content using a grind cage (Grindometer, Taisuke Equipment Co., Ltd.). did.

The evaluation criteria for the dispersed particle size of the pigment dispersion paste used in Examples 1 to 8 and Comparative Examples 1 to 4 are as follows:
○: ≦ 5 μm;
Δ: 6-9 μm;
X: ≧ 10 μm.

The evaluation criteria for the dispersed particle size of the solid tin curing catalyst / pigment dispersion paste used in Examples 9-12 and Comparative Examples 5-6 are as follows:
○: ≦ 5 μm;
Δ: 6-9 μm;
X: ≧ 10 μm.

Dispersion stability Pigment dispersion paste or 300 g of solid tin curing catalyst / pigment dispersion paste sample was placed in a metal container having an internal volume of 250 ml and stored in a constant temperature bath at 40 ° C. for up to 4 weeks. After the storage period, the solid component containing the precipitated solid tin curing catalyst was carefully peeled off and collected from the bottom of the container using a spatula or the like. The thickness of the collected solid component was measured, and the dispersion stability of the solid component was evaluated. The evaluation criteria are as follows:
○: ≦ 5 mm; usable, more preferable Δ: 6 to 10 mm; usable x: ≧ 11 mm; unusable.

Appearance of the cured electrodeposition coating film The cation electrodeposition coating composition of each example and each comparative example was applied to a carbarium steel sheet (JIS K5600 standard product, 150 × 70 × 0.5 mm) treated with zinc phosphate at a liquid temperature of 30. Electrodeposition coating was performed at 20 ° C. so that the dry coating film was 20 μm. After washing with water, baking was performed at 160 ° C. for 10 minutes to obtain a cured electrodeposition coating film. The appearance of the obtained cured electrodeposition coating film was evaluated by measuring the 60 ° surface glossiness using a gloss meter (micro gloss 60 °, BYK Gardner) to evaluate the appearance of the cured electrodeposition coating film.

The evaluation criteria for the cured electrodeposition paint appearance of the cationic electrodeposition paint compositions of Examples 1-12 and Comparative Examples 1-6 are as follows:
○: ≧ 80; usable, more preferable Δ: 79 to 76; usable x: ≦ 75; unusable.

Corrosion-resistant zinc phosphate-treated carballium steel sheet (JIS K5600 standard product, 150 × 70 × 0.5 mm), and the cationic electrodeposition coating composition of each example and each comparative example were dried at a liquid temperature of 30 ° C. Was electrodeposition coated so that the thickness of the film was 20 μm. After washing with water, baking was performed at 160 ° C. for 10 minutes to obtain a cured electrodeposition coating film. Two cuts having a length of about 100 mm were put in a perpendicular direction with a knife so as to reach the steel sheet, and then immersed in 55 ° C. salt water (concentration: 5%). After immersion for 240 hours, the steel sheet was taken out, washed with water and dried. The coating film around the cut part was peeled off using an adhesive tape, and the width of the part peeled off from the cut part was visually observed to evaluate the corrosion resistance.

The evaluation criteria for the corrosion resistance of the cured electrodeposition paints of the cationic electrodeposition paint compositions of Examples 1 to 12 and Comparative Examples 1 to 6 are as follows:
A: ≦ 1.5 mm;
○: 1.6-2 mm;
Δ: 2.1 to 2.5 mm;
×: ≧ 2.6 mm.

The evaluation results are summarized in Tables 1 to 3 below:

When D10 of the solid tin curing catalyst was less than 0.9 μm, the viscosity of the solid tin curing catalyst dispersed paste increased (Comparative Examples 1 and 2). When D10 of the solid tin curing catalyst was less than 0.3 μm, the viscosity of the solid tin curing catalyst-dispersed paste was further increased, and the viscosity was not appropriate for the dispersion work (Comparative Example 2). An increase in the viscosity of the solid tin curing catalyst dispersion paste may result in a decrease in productivity in the production of a cationic electrodeposition coating composition, which may be undesirable.
When D10 of the solid tin curing catalyst was 0.9 μm or more, the viscosity of the solid tin curing catalyst dispersed paste was preferable (Examples 1 to 8).

When D90 of the solid tin curing catalyst exceeded 209 μm, the dispersibility of the solid component containing the solid tin curing catalyst in the pigment dispersion paste was lowered (Comparative Examples 2 to 4). The dispersion stability of the solid component in the cationic electrodeposition coating materials according to Comparative Examples 2 to 4 decreased. A decrease in the dispersion stability of the solid component in the pigment dispersion paste or the cationic electrodeposition coating composition may be undesirable from the viewpoint of the storage period and the use period. Moreover, the external appearance of the cured electrodeposition coating film formed from the cationic electrodeposition coating composition according to Comparative Examples 2 to 4 was not preferable. In Comparative Examples 2 to 4, since the appearance of the formed cured electrodeposition coating film was not preferable, it was expected that the corrosion resistance was not preferable.
On the other hand, when D90 of the solid tin curing catalyst is 209 μm or less, the dispersibility and dispersion stability of the solid component in the pigment dispersion paste and the appearance of the cured electrodeposition coating film formed from the cationic electrodeposition coating composition are appropriate. (Examples 1-8). When D90 of the solid tin curing catalyst is 121 μm or less, the dispersibility and dispersion stability of the solid component in the pigment dispersion paste and the appearance of the cured electrodeposition coating film formed from the cationic electrodeposition coating composition are more preferable. (Examples 1-3 and 6-8).

  The pigment dispersion pastes according to Examples 1 to 8 were easier to operate than the pigment dispersion pastes according to Comparative Examples 1 and 2, and were preferable for producing a cationic electrodeposition coating composition. In addition, in Examples 1-3 and 5-8, the dispersion stability of the solid component of the obtained pigment dispersion paste or cationic electrodeposition coating composition is high, and cured electrodeposition formed from the cationic electrodeposition coating composition The appearance of the coating film was also preferable.

  Even if a solid tin curing catalyst / pigment dispersion paste was prepared without preparing a solid tin curing catalyst dispersion paste, preferred dispersion pastes were obtained (Examples 9 to 12). According to this aspect of the present invention, it is possible to obtain a cationic electrodeposition coating composition without preparing a solid tin curing catalyst dispersion paste, which can bring significant industrial advantages from the viewpoint of productivity. The solid tin curing catalyst / pigment-dispersed paste or cationic electrodeposition coating composition according to Examples 9 to 12 exhibits appropriate dispersion stability of the solid component, and the curing electrode formed from the cationic electrodeposition coating composition. The appearance of the coating film was also appropriate. The cationic electrodeposition coating compositions according to Examples 10 to 12 surprisingly showed more preferable corrosion resistance. Further, when D90 is 77 μm or less, the dispersibility and dispersion stability of the solid component in the solid tin curing catalyst / pigment dispersion paste, and the appearance and corrosion resistance of the cured electrodeposition coating film formed from the cationic electrodeposition coating composition are It was more preferable (Examples 10 to 12).

Claims (7)

A cationic electrodeposition coating composition comprising an amine-modified epoxy resin (a); a blocked isocyanate curing agent (b); and a solid tin curing catalyst (c),
The cationic electrodeposition coating composition, wherein the solid tin curing catalyst (c) has a D10 value of 0.9 μm or more and a D90 value of 209 μm or less.   2. The cationic electrodeposition coating composition according to claim 1, wherein the solid tin curing catalyst (c) has a D10 value of 0.9 μm to 27.5 μm and a D90 value of 9 μm to 209 μm.   The cationic electrodeposition coating composition according to claim 1 or 2, wherein the solid tin curing catalyst (c) has a D10 value of 0.9 µm to 11 µm and a D90 value of 9 µm to 110 µm.   The cationic battery according to any one of claims 1 to 3, further comprising at least one component selected from a pigment, a plasticizer, a surfactant, a coating film surface smoothing agent, an antioxidant, and an ultraviolet absorber. Coating composition. The cationic electrodeposition coating composition according to any one of claims 1 to 4, comprising an amine-modified epoxy resin (a); a blocked isocyanate curing agent (b); and a solid tin curing catalyst (c). A method comprising the following steps:
A step of mixing a solid tin curing catalyst (c) and a pigment dispersion resin to obtain a solid tin curing catalyst dispersion paste; and a binder obtained by mixing an amine-modified epoxy resin (a), a blocked isocyanate (b) and an aqueous solvent A process comprising: mixing a resin emulsion and the solid tin curing catalyst dispersion paste to obtain a cationic electrodeposition coating composition. A method for producing a cationic electrodeposition coating composition according to claim 4, comprising an amine-modified epoxy resin (a); a blocked isocyanate curing agent (b); a solid tin curing catalyst (c); and a pigment, The following steps:
Mixing the solid tin curing catalyst (c), the pigment and the pigment dispersion resin to obtain a solid tin curing catalyst / pigment dispersion paste; and mixing the amine-modified epoxy resin (a), the blocked isocyanate (b) and the aqueous solvent. A step of obtaining a cationic electrodeposition coating composition by mixing the binder resin emulsion obtained by mixing the solid tin curing catalyst / pigment dispersion paste,
The manufacturing method which does not include the process of preparing a solid tin hardening catalyst dispersion paste.   An article having a cured electrodeposition coating film obtained by coating with the cationic electrodeposition coating composition according to any one of claims 1 to 4.