JP2022071678A - Two-pack type coating composition - Google Patents

Abstract

To provide a coating composition which is excellent in brightness and is suitable for in-mold coating.SOLUTION: A two-pack type coating composition contains a main agent and a curing agent, in which the main agent contains polyol, a curing catalyst and particles of a bright pigment, the curing agent contains an isocyanurate compound, a hydroxyl value of the polyol is 300 mgKOH/g or more and 1,000 mgKOH/g or less, a content of the curing catalyst is 0.25 pts.mass or more and 10 pts.mass or less with respect to 100 pts.mass of the polyol, a content of a solvent is 30 mass% or less, and an aggregate of the particles of the bright pigment is 20 mass% or less based on the whole pigments of the bright pigment.SELECTED DRAWING: None

Description

The present invention relates to a two-component coating composition.

Coating films having various roles are formed on the surface of industrial products and the like. The coating film protects the object to be coated and at the same time imparts a beautiful appearance and excellent design. The coating film is generally formed by spray-coating a coating composition containing a solvent such as an organic solvent and / or an aqueous solvent, and then drying the coating film. However, in recent years, problems such as scattering of the solvent during spray painting, release of the solvent to the atmosphere in the drying process, and generation of CO ₂ have been regarded as problems. Furthermore, since spray painting requires a drying process, productivity tends to decrease.

Therefore, as a coating method instead of spray coating, in-mold coating in which coating is performed in a mold has been proposed (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2002-292638

An object of the present invention is to provide a two-component coating composition which is excellent in brilliance and suitable for in-mold coating.

In order to solve the above problems, the present invention provides the following aspects.
[1]
A two-component coating composition containing a main agent and a curing agent.
The main agent contains particles of a polyol, a curing catalyst and a bright pigment.
The curing agent contains an isocyanurate compound and contains.
The hydroxyl value of the polyol is 300 mgKOH / g or more and 1000 mgKOH / g or less.
The content of the curing catalyst is 0.25 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polyol.
The content of the solvent is 30% by mass or less,
A two-component coating composition in which the aggregate of the particles of the glitter pigment is 20% by mass or less of the total particles of the glitter pigment.

[2]
The two-component coating composition according to the above [1], wherein the isocyanurate compound contains a trimer of hexamethylene diisocyanate.

[3]
The two-component coating composition according to the above [1] or [2], wherein the polyol is at least one selected from the group consisting of polyester polyols, polyether polyols and polycarbonate polyols.

[4]
The ratio of the isocyanate group equivalent of the isocyanate compound to the hydroxyl group equivalent of the polyol: NCO / OH is 0.5 / 1 or more and 2/1 or less, according to any one of the above [1] to [3]. Two-component coating composition.

[5]
The item according to any one of [1] to [4] above, wherein the curing catalyst contains at least one organic metal catalyst containing a metal element selected from the group consisting of Bi, Zn, Al, Zr and Sn. Two-component coating composition.

[6]
The two-component coating composition according to any one of the above [1] to [5], which is used for in-mold coating.

According to the present invention, it is possible to provide a two-component coating composition which is excellent in brilliance and suitable for in-mold coating.

A coating film having a brilliant feeling (hereinafter, may be referred to as a brilliant coating film) has been proposed. The brilliant coating film is formed by a paint containing a brilliant pigment. The bright pigment is blended into the paint as fine particles. The color development property of the brilliant coating film is affected by the dispersibility of the brilliant pigment. When the brilliant pigments are uniformly dispersed and arranged in the coating film, the color development property of the brilliant coating film is improved and a brilliant feeling is obtained. However, when a paint having a small amount of solvent such as in-mold coating is used, the brilliant pigment is particularly liable to aggregate and the dispersibility is liable to decrease.

In the present embodiment, the aggregate of the particles of the brilliant pigment is 20% by mass or less of the particles of the brilliant pigment. That is, the particles of the brilliant pigment are highly dispersed. As a result, the light is easily reflected by the coating film, the color development property of the coating film is improved, and an excellent brilliant feeling can be obtained.

The two-component coating composition according to this embodiment is suitably used for in-mold coating. However, it does not exclude the use of the two-component coating composition according to the present embodiment in a coating method other than in-mold coating. For example, a two-component coating composition may be applied to open press coatings.

The two-component coating composition according to the present embodiment can be used as a material for a coating film located on the outermost side of a coated article, an intermediate coating film interposed between an object to be coated, and / or a base coat coating film. .. When a coating film located on the outermost side of the coated article is formed by the two-component coating composition according to the present embodiment, another coating film (for example, a primer layer) is provided between the object to be coated and the coating film. You may.

[Two-component coating composition]
The two-component coating composition according to the present embodiment contains a main agent and a curing agent. The main agent contains a polyol, a curing catalyst, and particles of a bright pigment. The curing agent contains an isocyanurate compound. By mixing the main agent and the curing agent, the polyol and the isocyanate compound react with each other to obtain a cured coating film. The base agent and / or the curing agent may be heated and / or vacuum degassed before mixing, respectively. As a result, the amount of water contained in the two-component coating composition obtained by mixing the two is reduced, and the appearance of the obtained coating film can be easily improved.

(Main agent)
The main agent contains particles of a polyol, a curing catalyst and a bright pigment. The polyol is a coating film forming resin. The polyol reacts with the curing agent, for example by heating, to form a three-dimensional cured coating. Hereinafter, curable resins containing a polyol contained in a two-component coating composition may be collectively referred to as a coating film-forming resin.

Hereinafter, each component will be described in detail.
<Glittering pigment>
The brilliant pigment gives a brilliant feeling to the coating film. By uniformly arranging the particulate brilliant pigment (hereinafter, may be referred to as brilliant particles) in the coating film, the brilliant feeling is enhanced.

In the two-component coating composition according to the present embodiment, most of the glittering particles are dispersed as primary particles. Specifically, in the two-component coating composition, the occupancy rate of the aggregates of the glittering particles is 20% by mass or less of the total amount of the glittering particles.

Aggregates are so-called secondary particles formed by aggregating a plurality of glittering particles (primary particles). The low number of secondary particles indicates that the glittering particles are highly dispersed. When the brilliant particles are highly dispersed in the two-component coating composition, the brilliant particles are uniformly arranged in the obtained coating film, and the color development property is improved. The ratio of the agglomerates to the total brilliant particles is preferably 10% by mass or less, more preferably 0%.

The area ratio of the agglomerates to the total brilliant particles calculated from the enlarged image of the cured coating film or the thin film-shaped main agent formed by the two-component coating composition is the total brilliance contained in the two-component coating composition. It may be regarded as the mass ratio of agglomerates to the particles.

The area ratio of the aggregate is obtained as follows. First, a sample (for example, obtained by sandwiching the main agent between slides) is observed with a video microscope, and the outer edge can be clearly confirmed in the observation field of view (for example, about 500 times or more and 1500 times or less). Calculate the total area of. Next, agglomerates whose outer edges can be clearly confirmed are selected from all the glittering particles in the same observation field, and the total area is calculated. By dividing the total area of the agglomerates by the total area of the brilliant particles, the area ratio of the agglomerates to the total brilliant particles can be obtained.

Glittering particles having a large primary particle diameter tend to take a stirring share when preparing a coating material, and tend to have high dispersibility. Therefore, it is desirable that the primary particle diameter of the brilliant particles, particularly the brilliant particles that have not been surface-treated (hereinafter, may be referred to as untreated brilliant particles) is large. The primary particle diameter of the untreated brilliant particles is not particularly limited and is appropriately set according to the material thereof. The primary particle size of the untreated brilliant particles is, for example, 20 μm or more. In this case, the dispersibility is improved, and the aggregation of the particles is more likely to be suppressed. The primary particle size of the untreated brilliant particles is preferably 25 μm or more, more preferably 28 μm or more.

The primary particle diameter of the surface-treated brilliant particles (hereinafter, may be referred to as treated brilliant particles) may be smaller than that of the untreated brilliant particles. The primary particle diameter of the treated brilliant particles is not particularly limited, and is appropriately set according to the material thereof. The primary particle diameter of the treated glitter particles may be smaller than, for example, 20 μm. This is because the brilliant particles surface-treated (typically, resin-coated or metal-coated) tend to have a large physical distance, and aggregation is easily suppressed by the action of the surface treatment agent. The primary particle diameter of the treated brilliant particles may be 3 μm or more. As a result, aggregation of particles is more likely to be suppressed. The primary particle diameter of the treated brilliant particles is preferably 5 μm or more, more preferably 6 μm or more.

The diameter of the aggregates (secondary particle diameter) present in the two-component coating composition is not particularly limited, but a smaller diameter is preferable from the viewpoint of brilliance.

The diameter of each particle can also be calculated from the video microscope. The observation field of view is set in the same manner as above, and primary particles of glittering particles (for example, aluminum particles) are selected. The diameter of a circle (equivalent circle) having the same area as the area of the primary particle is regarded as the diameter of the primary particle. The diameters of all the primary particles are calculated, and the average value thereof is taken as the particle diameter of the primary particles. The particle size of the aggregate can be calculated in the same manner.

The content of the glittering particles is not particularly limited. The concentration of the brilliant particles, that is, the mass ratio of the brilliant particles (PWC: mass%) to 100% by mass of the solid content of the two-component coating composition is, for example, 0.5% by mass or more and 20% by mass or less. good. The PWC of the glittering particles is preferably 3% by mass or more. The PWC of the glittering particles is preferably 15% by mass or less. The solid content of the two-component coating composition is all components except the solvent.

Glittering pigments were coated with metal particles (aluminum, chromium, gold, silver, copper, brass, titanium, nickel, nickel chromium, stainless steel, etc.), mica, metal oxides, pearl pigments, metals or metal oxides. Examples include glass flakes, silica flakes coated with metal oxides, graphite, hologram pigments and cholesteric liquid crystal polymers. These may be used alone or in combination of two or more.

<Other pigments>
The main agent may contain pigments other than bright pigments.
Other pigments include, for example, color pigments and extender pigments.

Examples of the coloring pigment include azochelate pigments, insoluble azo pigments, condensed azo pigments, diketopyrrolopyrrole pigments, benzimidazolone pigments, phthalocyanine pigments, indigo pigments, perinone pigments, perylene pigments, and dioxane. Organic coloring pigments such as based pigments, quinacridone based pigments, isoindolinone based pigments and metal complex pigments: Inorganic coloring pigments such as yellow lead, yellow iron oxide, red iron oxide, carbon black and titanium dioxide can be mentioned. These may be used alone or in combination of two or more.

Examples of extender pigments include calcium carbonate, barium sulfate, clay and talc. These may be used alone or in combination of two or more. The contents of the coloring pigment and the extender pigment are not particularly limited, and may be appropriately set according to the type and purpose of the pigment.

<Polyol>
The polyol is a coating film forming resin. The polyol reacts with the curing agent, for example by heating, to form a three-dimensional cured coating. Polyols have two or more hydroxyl groups per molecule. As a result, the hardness of the obtained coating film tends to increase. Polyols may be used alone or in combination of two or more.

The main agent preferably contains a polyol (A1) having 3 or more hydroxyl groups per molecule and a polyol (A2) having two hydroxyl groups per molecule. The ratio of the polyol (A1) to the polyol (A2) is not particularly limited. The proportion of the polyol (A2) may be 50% by mass or less, 40% by mass or less, and 30% by mass or less of the total of the polyol (A1) and the polyol (A2).

The hydroxyl value of the polyol is 300 mgKOH / g or more and 1000 mgKOH / g or less. When the hydroxyl value of the polyol is within the above range, the reaction rate between the polyol and the isocyanate compound becomes high when the main agent and the curing agent are mixed. Therefore, the painted product can be quickly released from the mold, and the productivity is improved. In addition, since a certain amount of heat of reaction is generated during the reaction, the adhesion of the coating film to the resin base material tends to be improved.

When two or more kinds of polyols are contained, the apparent hydroxyl value calculated based on the hydroxyl value and the mass ratio of each polyol may be 300 mgKOH / g or more and 1000 mgKOH / g or less. That is, the main agent may contain a polyol having a hydroxyl value of less than 300 mgKOH / g and / or a polyol having a hydroxyl value of more than 1000 mgKOH / g.

The hydroxyl value of the polyol (including the apparent hydroxyl value; the same applies hereinafter) is more preferably 350 mgKOH / g or more, and further preferably 500 mgKOH / g or more. The hydroxyl value of the polyol is more preferably 800 mgKOH / g or less, still more preferably 700 mgKOH / g or less.

The type of the polyol is not particularly limited. Examples of the polyol include polyester polyols, polyether polyols, polycarbonate polyols, polyacrylate polyols and polyhydric alcohols. These may be used alone or in combination of two or more. Among them, the polyol preferably contains at least one selected from the group consisting of polyester polyols, polyether polyols and polycarbonate polyols.

The polyester polyol preferably has a branched structure. The polyester polyol having a branched structure is prepared, for example, by reacting a trihydric or higher polyhydric alcohol compound with a 2 or higher polyvalent carboxylic acid and repeating the above reaction as necessary.

Commercially available polyester polyols include, for example, Desmophen VPLS2249 / 1 (manufactured by Sumika Cobestro Urethane Co., Ltd.), Desmophen 800 (manufactured by Sumika Cobestro Urethane Co., Ltd.), and Desmophen XP2488 (manufactured by Sumika Cobestro Urethane Co., Ltd.). , Kuraray polyol P-510 (manufactured by Kuraray Co., Ltd.) and Kuraray polyol F-510 (manufactured by Kuraray Co., Ltd.).

Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and blocks thereof. Polyether polyols may be prepared by adding ethylene oxide and / or propylene oxide to the polyhydric alcohol compound. By the above procedure, a polyether polyol having a divalent or trivalent or higher number of OH functional groups per molecule can be prepared.

Examples of commercially available products of the polyether polyol include the Sanniks series manufactured by Sanyo Chemical Industries, Ltd. Specific examples thereof include Sanniks GP-250, Sanniks GP-400, Sanniks PP-200 and Sanniks GP-600.

Polycarbonate polyols can be prepared, for example, by reacting a polyvalent polyol with dimethyl carbonate.

Examples of commercially available polycarbonate polyols include Duranol T5650E (manufactured by Asahi Kasei Corporation), C-590 (manufactured by Kuraray Co., Ltd.) and ETERNCOLL PH-50 (manufactured by Ube Kosan Co., Ltd.).

Examples of the polyhydric alcohol include ethylene glycol, glycerin, trimethylolpropane, propylene glycol, tetramethylene glycol and pentaerythritol.

The weight average molecular weight (Mw) of the polyol is not particularly limited. The Mw of the polyol may be appropriately set according to the hydroxyl value and the like.

The main agent may contain a polyol having an average number of hydroxyl groups of less than 3. The main agent may contain a coating film-forming resin other than the polyol. Examples of the coating film-forming resin include acrylic resin, polyester resin, alkyd resin, polyether resin, polyolefin resin, polyurethane resin, polycarbonate resin, melamine resin, epoxy resin and carbodiimide resin. Other coating film forming resins may be used alone or in combination of two or more.

<Curing catalyst>
The curing catalyst promotes the curing reaction. The curing catalyst is not particularly limited. From the viewpoint of the accelerating effect, as the curing catalyst, for example, at least one organometallic catalyst containing a metal element selected from the group consisting of Bi, Zn, Al, Zr and Sn is preferable. Among them, at least one organometallic catalyst containing a metal element selected from the group consisting of Bi, Zn, Al and Zr is preferable.

Examples of the organometallic catalyst containing Bi include bismuth carboxylic acid and salts thereof. Examples of the Zn-containing organometallic catalyst include zinc complex catalysts. Examples of the organometallic catalyst containing Al include an aluminum complex catalyst. Examples of the organometallic catalyst containing Zr include a zirconium chelate catalyst. Examples of the organometallic catalyst containing Sn include dialkyl tin dicarboxylate such as dibutyl tin dilaurate, dioctyl tin dilaurate, and dibutyl tin diacetate; tin oxide compounds such as dibutyl tin oxide; tin carboxylates such as tin 2-ethylhexanoate. ..

Examples of commercially available products of organic metal catalysts containing Bi include K-KAT 348 (manufactured by Kusumoto Kasei Co., Ltd.) and K-KAT XK-640 (manufactured by Kusumoto Kasei Co., Ltd.). Examples of commercially available products of organometallic catalysts containing Zr include K-KAT 4205, K-KAT XC-9213, K-KAT XC-A209, and K-KAT 6212 (all manufactured by Kusumoto Kasei Co., Ltd.). Examples of commercially available products of organometallic catalysts containing Al include K-KAT 5218 (manufactured by Kusumoto Kasei Co., Ltd.). Commercially available products of organometallic catalysts containing Zn include, for example, K-KAT XK-314, K-KAT XK-635, K-KAT XK-639, and K-KAT XK-620 (all manufactured by Kusumoto Kasei Co., Ltd.). Can be mentioned. Examples of commercially available organometallic catalysts containing Sn include TVS TIN LAU (manufactured by Nitto Kasei Co., Ltd.).

The content of the curing catalyst is, for example, 0.25 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the coating film forming resin. As a result, the curing reaction of the coating film-forming resin proceeds rapidly. Therefore, a coating film having excellent appearance and physical characteristics can be obtained by forming a layer by in-mold coating. The content of the curing catalyst is more preferably 0.5 parts by mass or more with respect to 100 parts by mass of the coating film forming resin. The content of the curing catalyst is more preferably 7 parts by mass or less with respect to 100 parts by mass of the coating film forming resin.

(Hardener)
The curing agent crosslinks the coating film-forming resin such as a polyol, and the corrosion resistance and durability of the obtained coating film are improved.

The curing agent contains an isocyanurate compound. The isocyanurate compound is a trimer of an isocyanate compound and has a ring structure.

The isocyanate compound is not particularly limited, and a known curing agent for a two-component reaction type composition is used. Examples of the isocyanate compound include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), and the like. Aromatic diisocyanates such as xylylene diisocyanate (XDI) and methaxylylene diisocyanate (MXDI); hexamethylene diisocyanate (HDI), tetramethylene diisocyanate, 2-methyl-pentane-1,5-diisocyanate, 3-methyl-pentane-1 , 5-Diisocyanate, lysine diisocyanate, trioxyethylene diisocyanate and other aliphatic diisocyanates; isophorone diisocyanate (IPDI), cyclohexyl diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, norbornan diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, Examples thereof include alicyclic diisocyanates such as hydrogenated tetramethylxylene diisocyanate. These may be used alone or in combination of two or more.

Among them, aliphatic diisocyanates are preferable, and HDI is more preferable because the viscosity is relatively low. These isocyanate trimers are particularly reactive with polyols. Therefore, it is more preferably used as a coating layer forming method by in-mold coating.

Ratio of isocyanate group equivalent of isocyanate compound to hydroxyl group equivalent of polyol: NCO equivalent / OH equivalent is preferably 0.5 / 1 or more and 2/1 or less, and more preferably 0.9 / 1 or more and 1.2 / 1 or less. .. When the equivalent ratio is within the above range, the curability is high, and it is particularly preferably used for forming a coating layer by in-mold coating.

The curing agent may contain other curing agents other than the isocyanate compound. Examples of other curing agents include amino resins, the monomer or dimer of the isocyanate compound, the biuret of the isocyanate compound, the blocked product of the isocyanate compound, the epoxy compound, the aziridine compound, the carbodiimide compound, and the oxazoline compound. .. These may be used alone or in combination of two or more.

The content of the curing agent is, for example, 35% by mass or more and 90% by mass or less of the resin solid content of the coating composition. The content of the curing agent is preferably 45% by mass or more, more preferably 55% by mass or more. The content of the curing agent is preferably 85% by mass or less, more preferably 70% by mass or less.

(solvent)
The content of the solvent is 30% by mass or less. According to the present embodiment, aggregation of bright particles is suppressed even in a composition having such a small amount of solvent and high viscosity. Therefore, the coating film having a brilliant feeling can be formed by the in-mold coating, and the content of the solvent is preferably 20% by mass or less, more preferably 10% by mass or less, and may be 0%.

The solvent is not particularly limited. The solvent is usually an organic solvent. Examples of the organic solvent include ester solvents such as ethyl acetate, butyl acetate, isopropyl acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate; propylene glycol monomethyl ether and ethylene glycol monomethyl ether. , Methylmethoxybutanol, ethoxypropanol, ethylene glycol isopropyl ether, ethylene glycol-t-butyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, methoxybutanol, propylene glycol monobutyl ether and other ether solvents; methanol, ethanol, butanol, Alcohol-based solvents such as propyl alcohol; Ketone-based solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; aliphatic hydrocarbon-based solvents such as swazole, shelsol, and mineral spirit; xylene, toluene, Solbesso-100 (S-100), Examples include aromatic solvents such as Solbesso-150 (S-150). These may be used alone or in combination of two or more.

<Light stabilizer>
The main agent may contain a light stabilizer. As a result, the weather resistance is improved, so that the two-component coating composition is preferably used for painting the exterior body. The light stabilizer efficiently traps alkyl radicals (R ·) and peroxy radicals (ROO ·) generated by ultraviolet rays. Examples of the light stabilizer include hindered amine compounds (HALS) and hindered phenol compounds. Among them, HALS is preferable.

The structure of HALS is not particularly limited. HALS has, for example, one or more piperidine skeletons (typically 2,2,6,6-tetraalkylpiperidine skeletons) in the molecule. Such HALS is used alone by one type and in combination of two or more types.

Specific examples of the preferred HALS include HOSTAVIN (registered trademark) 3058 (manufactured by Clariant Chemicals, Inc., pKb = 11.4, molecular weight 449, N-CO-R type), Tinuvin (registered trademark) 123 (hereinafter, BASF). Examples thereof include pKb = 9.6, molecular weight 737, N-OR type), Tinuvin152 (pKb = 7.0, 9.4, molecular weight 757, N-OR type), and Tinuvin5100 (pKb = 9.6). ..

Specific preferred hindered phenolic photostabilizers include Irganox 1010, Irganox 1035, Irganox 1076, Irganox 1135, Irganox 1726, Irganox 1035, Irganox 1035, Irganox 1076, and Irganox 1135, all of which are Irganox 1135. Can be mentioned.

<UV absorber>
The main agent may contain an ultraviolet absorber. This improves weather resistance. Ultraviolet absorbers (UVA) are used in place of or with light stabilizers. Above all, it is preferable to use UVA and a light stabilizer in combination. As a result, the weather resistance is further improved.

Examples of UVA include benzotriazole-based compounds, triazine-based compounds, benzophenone-based compounds and benzoate-based compounds. Specific examples of UVA include Tinuvin326, Tinuvin384-2, Tinuvin900, Tinuvin400, Tinuvin405, Tinuvin460, Tinuvin477, and Tinuvin479 (all manufactured by BASF).

(others)
The two-component coating composition may contain other components as needed. Other ingredients include, for example, additives commonly used in the coating and paint fields. Specific examples thereof include various pigments, surface modifiers, viscosity modifiers, antioxidants, ultraviolet inhibitors, defoamers, catalyst aids, rust inhibitors, sedimentation inhibitors, dispersants and the like. These additives may be added to the main agent or the curing agent. The amount of the additive is not particularly limited and can be appropriately set as needed.

[In-mold coating]
In-mold coating is a method of forming a coating layer in a mold. In the in-mold coating, the coated body is a step of injecting the above-mentioned two-component coating composition between the surface of the object to be coated and the cavity surface and / or the core surface of the mold, and the injected two-component type. Manufactured by a method comprising a step of curing the coating composition. The curing step may be performed in the mold.

According to the in-mold coating, since the coating layer is formed in the mold, it is possible to prevent dust and the like from adhering between the object to be coated and the coating layer and dust and the like from being mixed inside the coating layer. Will be done. In addition, since it is not easily affected by the surface condition of the object to be coated, the pattern of the mold can be transferred to the coating layer with high accuracy. In addition, since the amount of the solvent contained in the coating composition is small, a drying step for removing the solvent is not required, and the productivity is improved. Furthermore, it is possible to form a thick coating layer in which sagging and armpits are suppressed.

The resin object to be coated may also be molded in the same mold. In this case, the coated body is formed between the step of molding the resin-made object to be coated in the mold, the surface of the obtained object to be coated, and the cavity surface and / or the core surface of the mold. It is produced by a method comprising a step of injecting a liquid coating composition and a step of curing the injected two-component coating composition. The curing step may be performed in the mold.

The viscosity of the two-component coating composition when injected into the mold is preferably 100 mPa · s or more and 500 mPa · s or less. If necessary, the main agent and / or the curing agent of the two-component coating composition may be heated to adjust the viscosity.

The object to be coated made of resin may be a thermoplastic resin or a thermosetting resin. Examples of the resin constituting the object to be coated made of the resin include polypropylene (PP) resin, acrylonitrile / butadiene / styrene copolymer (ABS resin), polycarbonate (PC) / ABS resin, and PC / acrylonitrile / ethylene-propylene-. Diene-styrene copolymer (AES resin), AES resin, PC / polybutylene terephthalate (PBT) resin, PC / polyethylene terephthalate (PET) resin, PC resin, polymethylmethacrylate (PMMA) resin, GF-PBT resin, GF -Polyforme (PA) resin, noryl / GTX resin, polyvinyl chloride (PVC resin), acrylonitrile / styrene / acrylic (ASA) resin, carbon fiber reinforced plastic (CFRP resin), glass fiber reinforced plastic (GFRP resin) can be mentioned. ..

The coating layer formed by the two-component coating composition has an excellent brilliant feeling. Therefore, the obtained painted article is suitably used, for example, for the exterior of automobiles and building applications. In particular, the obtained painted article is suitably used for automobile parts such as roof rails.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the examples, "parts" and "%" are based on mass unless otherwise specified.

[Example 1]
Polyol (Sanniks GP-250, manufactured by Sanyo Kasei Kogyo Co., Ltd., hydroxyl value 670 mgKOH / g, average number of hydroxyl groups 3) 100 parts, curing catalyst (K-KAT XK-640, manufactured by Kusumoto Kasei Co., Ltd., organic metal containing Bi) The main agent was prepared by mixing 3 parts (catalyst) (active ingredient amount) and bright particles (sil beads M-300CP, manufactured by Asahi Kasei Co., Ltd., untreated aluminum particles, primary particle diameter 30 μm). In the table, the amount of brilliant particles is described as the mass ratio (PWC) of the brilliant particles to 100% by mass of the solid content of the two-component coating composition.

Separately, 218 parts of an isocyanurate compound (Death Module N3600, manufactured by Sumika Covestro Urethane Co., Ltd., Nurate form of HDI) was prepared as a curing agent.
NCO / OH = 1.0 / 1.0, and the solvent content as a two-component coating composition was 0%.

An appropriate amount of the main agent was sandwiched between slides and observed with a video microscope (manufactured by KEYENCE, device name VHX-6000). In the observation field of view, agglomerates in which two or more brilliant particles were in close contact with each other and other primary particles were distinguished. The mass ratio of the agglomerates to the total brilliant particles was calculated as described above.

[Examples 2 to 12 and Comparative Examples 1 to 6]
The main agent and the curing agent were prepared by the same procedure as in Example 1 except that the type and amount of each component were changed as described in Tables 1 and 2, and the aggregation ratio was calculated.
In Examples 2, 3, 6, 8 and Comparative Examples 1, 2, 5, and 6, ethyl acetate, which is an organic solvent, was mixed with the main agent. Tables 1 and 2 show the amount of solvent as a ratio to the two-component coating composition.

The components in the above table are as follows.
(Polyol)
Sanniks GP-400: manufactured by Sanyo Chemical Industries, Ltd., polyether polyol, hydroxyl value 400 mgKOH / g, average number of hydroxyl groups 3
Desmophen VPLS2249 / 1: Made by Sumika Cobestro Urethane Co., Ltd., polyester polyol, hydroxyl value 512 mgKOH / g, average number of hydroxyl groups 3 or more

(Glittering particles)
Sylves M-150CP: Asahi Kasei Corporation, untreated aluminum particles, primary particle diameter 15 μm
Sylves M-100CP: Asahi Kasei Corporation, untreated aluminum particles, primary particle diameter 10 μm
Aluminum paste CP-R515H: Asahi Kasei Corporation, resin-coated aluminum particles, primary particle diameter 15 μm
Aluminum paste CP-R705H: Asahi Kasei Corporation, resin-coated aluminum particles, primary particle diameter 7 μm
XIRALLIC T60-21 WNT ORACLE (registered trademark) RED: Merck & Co., metal-coated mica particles, primary particle diameter 19 μm
IRIODIN ULTRA 7205 WNT: Merck & Co., metal-coated mica particles, primary particle diameter 30 μm

The coating film produced by the two-component coating composition prepared in Examples 1 to 12 is glossy and exhibits a good brilliant feeling. On the other hand, the coating film produced by the two-component coating composition prepared in Comparative Examples 1 to 6 is inferior in gloss and lacks a brilliant feeling.

The two-component coating composition of the present invention can be suitably used in a coating method different from the conventional spray coating, such as a coating layer forming method by in-mold coating. According to the two-component coating composition of the present invention, a coating film having an excellent brilliance can be obtained, and therefore, it is particularly preferably used for exterior use.

Claims (6)

A two-component coating composition containing a main agent and a curing agent.
The main agent contains particles of a polyol, a curing catalyst and a bright pigment.
The curing agent contains an isocyanurate compound and contains.
The hydroxyl value of the polyol is 300 mgKOH / g or more and 1000 mgKOH / g or less.
The content of the curing catalyst is 0.25 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polyol.
The content of the solvent is 30% by mass or less,
A two-component coating composition in which the aggregate of the particles of the glitter pigment is 20% by mass or less of the total particles of the glitter pigment. The two-component coating composition according to claim 1, wherein the isocyanurate compound contains a trimer of hexamethylene diisocyanate. The two-component coating composition according to claim 1 or 2, wherein the polyol is at least one selected from the group consisting of polyester polyols, polyether polyols, and polycarbonate polyols. The two liquids according to any one of claims 1 to 3, wherein the ratio of the isocyanate group equivalent of the isocyanate compound to the hydroxyl group equivalent of the polyol: NCO / OH is 0.5 / 1 or more and 2/1 or less. Mold coating composition. The two-component type according to any one of claims 1 to 4, wherein the curing catalyst contains at least one organometallic catalyst containing a metal element selected from the group consisting of Bi, Zn, Al, Zr and Sn. Coating composition. The two-component coating composition according to any one of claims 1 to 5, which is used for in-mold coating.