JPH11290768A - Formation of double layered coated film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the failure that preservation stability is insufficient and the sufficient curing of a base coating film of an under layer is not obtained because of the reaction of a cross-linking agent in a coating line to consume a part thereof. SOLUTION: A base coat (A) containing a compound (a) containing an epoxy group and a hydroxy group in the same molecule, a phenyl silanol based compound (b) and a color pigment (c) is applied, then a clear coat (B) containing the compound (a) containing epoxy group and hydroxyl group in the same molecule, the phenyl silanol based compound (b) and an aluminum chelate compound (d) is applied on the uncured surface thereof and the cross-linking hardening of both coating film of the base coat (A) and the clear coat (B) is accelerated by the aluminum chelate compound contained in the coating film of the clear coat (B).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a multilayer coating film comprising a colored coating film and a clear coating film.

[0002]

2. Description of the Related Art A base coat containing a hydroxyl group-containing resin and a coloring pigment, and a clear coat containing a hydroxyl group-containing resin and a polyisocyanate compound (crosslinking agent) are coated on a wet-on-wet basis. Kuriako-
A method for forming a multi-layer coating film in which both a base coat and a clear coat are cross-linked and cured by a crosslinking agent in the coating film is already known. According to this method, the base coat has excellent storage stability because it does not contain a cross-linking agent, and has an effect that both coating films can be cured at a low temperature of 120 ° C. or less by the cross-linking agent. I have.

[0003] However, the hydroxyl group-containing resin of the clear coat and the crosslinking agent easily react at room temperature, so that their storage stability is not sufficient. Has the disadvantage that the curing of the basecoat film is insufficient. In addition, the hydroxyl group-containing resin of the base coat has a high molecular weight so as to be crosslinked with a small amount of a crosslinking agent as much as possible, making it difficult to obtain a high solid.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to coat a base coat and a clear coat on a wet-on-wet basis and to form a base coat with a crosslinking agent contained in the clear coat. And to eliminate the above-mentioned deficiencies in the method of crosslinking and curing both coating films of clear coat and
Its features are a paint containing an epoxy group-containing compound, a hydroxyl group-containing compound, a phenylsilanol compound and a coloring pigment as a base coat, and an epoxy group-containing compound, a phenylsilanol compound and an aluminum chelate as a clear coat. The use of a paint containing a compound. as a result. Finding that the purpose can be achieved,
The present invention has been completed.

That is, the present invention provides the following method for forming a multilayer coating film.

Method 1: A base containing a compound (a) containing an epoxy group and a hydroxyl group in the same molecule, a phenylsilanol compound (b) and a coloring pigment (c)
(A), and then, on this uncured coated surface, a compound (a) containing an epoxy group and a hydroxyl group in the same molecule,
A clear coat (B) containing a phenylsilanol-based compound (b) and an aluminum chelate compound (d) is applied, and the aluminum chelate compound contained in the clear coat (B) coating film is coated. A cross-linking curing of both the base coat (A) and the clear coat (B).

Method 2: A base coat (C) containing an epoxy group-containing compound (e), a hydroxyl group-containing compound (f), a phenylsilanol-based compound (b) and a coloring pigment (c) is applied. Then, the uncured coated surface is coated with the above-mentioned clear coat (B), and the base is coated with the aluminum chelate compound contained in the clear coat (B) coating film.
A method for forming a multilayer coating film, comprising accelerating the crosslinking and curing of both the coating film (C) and the clear coating (B).

Method 3: The above-mentioned base coat (A) is applied, and the epoxy group-containing compound (e), the hydroxyl group-containing compound (f), and the phenylsilanol-based compound ( b) and a clear coat (D) containing the aluminum chelate compound (d), and the base coat (A) is coated with the aluminum chelate compound contained in the coated film of the clear coat (D). A) and Kuriako-
(D) a method for forming a multilayer coating film, characterized by accelerating the crosslinking and curing of both coating films.

Method 4: The above-mentioned base coat (C) is applied, and then, the uncured coated surface is applied with the above-described clear coat (D), and the coated film of the clear coat (D) is applied. A method for forming a multilayer coating film, wherein the aluminum chelate compound contained therein promotes the cross-linking and curing of both the base coat (C) and the clear coat (D).

The phenol silanol compound in these methods 1 to 4 has the general formula Ph _n Si (OH) _{4 -n}
(Wherein, Ph is a phenyl group, and _n is an integer of 2 or 3).

Hereinafter, the method for forming a multilayer coating film of the present invention will be described in more detail.

Method 1 : A base containing a compound (a) containing an epoxy group and a hydroxyl group in the same molecule, a phenylsilanol-based compound (b) and a coloring pigment (c)
(A), and then, on this uncured coated surface, a compound (a) containing an epoxy group and a hydroxyl group in the same molecule,
A clear coat (B) containing a phenylsilanol-based compound (b) and an aluminum chelate compound (d) is applied, and the aluminum chelate compound contained in the clear coat (B) coating film is coated. A cross-linking curing of both the base coat (A) and the clear coat (B).

The base coat (A) is a paint to be applied prior to the clear coat (B), and is a compound (a) containing an epoxy group and a hydroxyl group in the same molecule, and a phenylsilanol-based compound. Liquid paint containing a compound (b) and a color pigment (c) to form a solid color tone or metallic tone coating film.

The compound (a) is a compound containing an epoxy group and a hydroxyl group in the same molecule. For example, an epoxy group-containing vinyl monomer and a hydroxyl group-containing vinyl monomer are essential components, and if necessary, other vinyl monomers are contained. Can be prepared by copolymerizing these.

An epoxy group-containing vinyl monomer is a compound having at least one epoxy group and at least one polymerizable double bond in one molecule, and examples thereof include compounds represented by the following general formula. Of these epoxy group-containing vinyl monomers, monomers having an alicyclic structure are suitable.

[0016]

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[0017]

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[0018]

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[In each formula, R ₁ is a hydrogen atom or a methyl group, R ₂ is a divalent saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, and R ₃ is a divalent hydrocarbon group having 1 to 10 carbon atoms. Hydrogen group, m is 1
And an integer of from 10 to 10.] The hydroxyl group-containing vinyl monomer is a compound having at least one hydroxyl group and at least one polymerizable double bond in one molecule, for example, hydroxyethyl (meth) acrylate,
C2-C10 such as hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate
Monoesters of the above-mentioned glycols and (meth) acrylic acid can be suitably used.

Other vinyl monomers which can be used for the preparation of compound (a) are other than the epoxy group-containing vinyl monomer and the hydroxyl group-containing vinyl monomer,
A compound having one or more polymerizable double bonds in one molecule. For example, an esterified product of (meth) acrylic acid and a monoalcohol having 1 to 24 carbon atoms; an esterified product of (meth) acrylic acid and an alkoxyalkyl ester having 2 to 18 carbon atoms;
(Meth) acrylic acid and an alkenyl ester having 2 to 8 carbon atoms; (meth) acrylic acid and an alkenyloxyalkyl ester having 3 to 18 carbon atoms; a vinyl aromatic compound such as styrene, methylstyrene, and vinyltoluene; Olefin compounds such as isoprene; and other monomers such as acrylonitrile, methyl isopropenyl ketone, and vinyl acetate.

The compound (a) is obtained by copolymerizing an epoxy group-containing vinyl monomer and a hydroxyl group-containing vinyl monomer as essential components, and further using other vinyl monomers as required, in a usual manner. be able to. The composition ratio of these monomers is, based on the total weight of these monomers, 20 to 50% for epoxy group-containing vinyl monomers, 10 to 40% for hydroxyl group-containing vinyl monomers, and 50% or less for other vinyl monomers. Preferably, there is. Further, the number average molecular weight of the compound (a) is suitably in the range of about 3000 to about 200,000.

The phenylsilanol-based compound (b) is a compound represented by the general formula: Ph _n Si (OH) _{4 -n} (wherein Ph is a phenyl group, and _n is an integer of 2 or 3). Preferably, there are diphenylsilanediol and triphenylsilanol.

As the coloring pigment (c), ordinary pigments for paints can be used, for example, titanium oxide, zinc white, carbon black, cadmium red, molybdenum red, chrome ero, chromium oxide, prussian bull, cobalt bull. -, Inorganic or organic solid color pigments such as azo pigments, phthalocyanine pigments, quinacridone pigments, isoindoline pigments, sulene pigments and perylene pigments; scaly aluminum, mica and mica coated with metal oxide And metallic pigments such as mica-like iron oxide, and the like, but are not limited thereto.

In the base coat (A), the phenylsilanol-based compound (b) is preferably used in an amount of 0.5 to 10 parts, more preferably 2 to 5 parts, per 100 parts by weight of the compound (a).
It is preferable that the color pigment (c) is blended with the base coat (A) in a single coating film (the thickness of the cured coating film is about 10 to 40 μm) or more so as to cover the base color. Bee
If necessary, coating additives such as anti-settling agents, curing catalysts, surface conditioners and ultraviolet absorbers can be added to the coat (A).

The base coat (A) can be prepared by mixing and dispersing the above components in an organic solvent. The viscosity is adjusted to 10 to 30 seconds (for a hood cup # 4/20 ° C.), and the air spray is performed. -, Airless spraying, electrostatic coating and other spray coating machines. The coating thickness is
The thickness of the cured coating film is about 10 to 40 μm. Such a single coating of the base coat (A) hardly undergoes crosslinking and curing at a temperature of 100 ° C. or lower. The clear coat (B) is to be applied to the uncured surface of the base coat (A), and is a compound (a) containing an epoxy group and a hydroxyl group in the same molecule, a phenylsilanol-based compound. This is a liquid paint for forming a transparent coating film, containing (b) and an aluminum chelate compound (d).

Among these components, the compounds (a) and (b) described in the base coat (A) can be used in the same manner.

As the aluminum chelate compound (d), an aluminum chelate compound containing a compound capable of forming a keto-enol tautomer stably as a ligand is particularly preferable. Compounds constituting keto-enol tautomers include β-diketones (such as acetylacetone), acetoacetates (such as methyl acetoacetate), malonic esters (ethyl malonate), and a hydroxyl group at the β-position. And aldehydes having a hydroxyl group at the β-position (such as salicylaldehyde). In particular, the use of β-diketones and acetoacetates gives favorable results.

Preferred examples of these aluminum chelate compounds include tris (ethylacetoacetate).
G) aluminum, monoacetylacetonato bis (ethylacetoacetate) aluminum, tris (n-propylacetoacetate) aluminum, tris (n-
Butyl acetoacetate) aluminum, monoethyl acetoacetate bis (acetylacetonato) aluminum, tris (acetylacetonato) aluminum, tris (propionylacetonato) aluminum, monoacetylacetonatobis (propionylacetonato) Aluminum and the like.

In the clear coat (B), the compound (b) is used in an amount of 0.5 to 1 per 100 parts by weight of the compound (a).
0 parts, especially 2 to 5 parts, compound (d) is 0.1 to 10 parts,
Particularly, a ratio of 1 to 5 parts is preferable.

The above-mentioned colored pigment (c) can be blended with the clear coat (B) within a range that does not impair the transparency, and, if necessary, a curing catalyst, an ultraviolet absorber, and a light-absorbing agent. Paint additives such as stabilizers and surface conditioners can be added.

Since the viscosity of the clear coat (B) containing the compound (a), the compound (b) and the compound (d) increases when left at room temperature, the components containing the compound (a) and the compound (b) It is preferable to separate the component (d) from the component containing the compound (d) in advance, and use the two components immediately before coating.

The clear coat (B) can be prepared by mixing and dispersing these compounds (a), (b) and (d) in an organic solvent and having a viscosity of 1%.
Adjust to 0-30 seconds (Ford cup # 4/20 ° C)
It can be applied by a spray coating machine such as an air spray, an airless spray, and an electrostatic coating. The coating thickness of the cured coating is about 20 to 70 μm.

In method 1, an undercoat (such as a cationic electrodeposition paint) or an intermediate coat (such as a polyester resin) is appropriately applied to any metal or plastic object to be applied to the outer panel of the automobile, and then heat-cured. The base coat (A) is coated with a cured coating film to a thickness of about 10 to 40 μm using a spray coating machine or the like on the surface to be coated. Forming a film,
After leaving it for 1 to 10 minutes if necessary, apply the clear coat (B) to the uncured coating surface with a spray coating machine or the like so that the cured coating film has a thickness of about 20 to 70 μm. By forming a colorless or colored transparent coating film and forcibly drying the coating film at a temperature of 100 ° C. or lower, the two coating films are crosslinked and hardened to form a multilayer coating film which is the object of the present invention.

Although the mechanism of crosslinking and curing of both the basecoat (A) and clearcoat (B) coatings in method 1 has not been fully elucidated, the compound ( When b) and compound (d) coexist, the reaction between the epoxy group and the hydroxyl group in compound (a) is accelerated and crosslinked and cured, and in the coating of base coat (A), compound (b)
It is thought that the interaction between the epoxy group and the hydroxyl group in the compound (a) is promoted by the interaction between the compound and the compound (d) penetrating from the clear coat (B) coating film adjacent to the upper layer, resulting in crosslinking and curing. It is.

Method 2 : A base coat (C) containing an epoxy group-containing compound (e), a hydroxyl group-containing compound (f), a phenylsilanol-based compound (b) and a coloring pigment (c) is applied. Then, the uncured coated surface is coated with the clear coat (B) described in Method 1, and the aluminum coat compound contained in the clear coat (B) coats the base coat (B). This is a method for forming a multilayer coating film, characterized by accelerating the crosslinking and curing of both the coating films (C) and (B).

The base coat (C) used in the method 2 is as follows:
A liquid paint for forming a solid or metallic coating film containing an epoxy group-containing compound (e), a hydroxyl group-containing compound (f), a phenylsilanol-based compound (b) and a coloring pigment (c). Among them, the compound (b) and the coloring pigment (c) are the above-mentioned base-
(A) can be similarly used.

The epoxy group-containing compound (e) is a compound containing two or more epoxy groups in one molecule. Specifically, an epoxy group-containing vinyl monomer exemplified in the compound (a) described in the method 1 and, if necessary, other vinyl monomers are used in combination, and these are (co) polymerized by an ordinary method. Can be prepared.

In the compound (e), the ratio of the epoxy group-containing vinyl monomer to the other vinyl monomer is 30 to 100% based on the total weight of these monomers, and the ratio of the other vinyl monomer is 30 to 100%.
Is preferably 70% or less. The number average molecular weight of the compound (e) is suitably from about 3000 to about 200,000. As the epoxy group-containing compound (e), dicyclopentadienedioxide, bis (2,3 epoxy-cyclopentenyl) ether, bisepoxydicyclopentyl ether of ethylene glycol, and 3,4 epoxy-6
-Methylcyclohexyl-methyl-cyclohexanecarboxylate, bis (3,4-epoxy-6-methyl-
Cyclohexylmethyl) adipate is also included.

The hydroxyl group-containing compound (f) contains 2
It is a compound containing two or more hydroxyl groups. In particular,
It can be prepared by using the hydroxyl group-containing vinyl monomer exemplified in the above compound (a) and, if necessary, other vinyl monomers, and subjecting them to (co) polymerization in a usual manner.

In the compound (f), the ratio of the hydroxyl group-containing vinyl monomer to the other vinyl monomer is based on the total weight of these monomers.
Is preferably 20 to 100%, and other vinyl monomers are preferably 80% or less. The number average molecular weight of the compound (f) is suitably from about 3000 to about 200,000. In the base coat (C), the composition ratio of the compound (e) to the compound (f) is 20 to 60% based on the total weight of both compounds, and the compound (f) Is preferably 40 to 80%. The phenylsilanol-based compound (b) is preferably used in an amount of 0.5 to 10 parts, more preferably 2 to 5 parts, per 100 parts by weight of the total of the compound (e) and the compound (f). It is preferable that the color pigment (c) is blended with a base coat (C) in a single coating film (thickness of the cured coating film is about 10 to 40 μm) or more so as to cover the base color. The basecoat (C) may further contain paint additives such as an antisettling agent and a curing catalyst, if necessary.

The base coat (C) can be prepared by mixing and dispersing these components in an organic solvent. The viscosity is adjusted to 10 to 30 seconds (for a hood cup # 4/20 ° C.), and the air spray is prepared. -, Can be applied with a spray coating machine such as an airless spray or electrostatic coating. The thickness of the coating is usually about 10 to 40 μm for the cured coating film. Such a single coating of the basecoat (C) hardly undergoes crosslinking and curing at a temperature of 100 ° C. or less.

The multi-layer coating film obtained by the method 2 was prepared in the same manner as the method 1 except that the base coat (A) was replaced with the base coat (C). Can be formed. The mechanism of the crosslinking and curing of both the base coat (C) and the clear coat (B) in the method 2 is as follows.
In the clear coat (B) coating film, the reaction between the epoxy group and the hydroxyl group in the compound (a) is promoted by the coexistence of the compound (b) and the compound (d), whereby the epoxy resin is crosslinked and hardened.
In the coating film (c), the interaction between the compound (b) and the compound (d) penetrating from the clear coat (B) coating film adjacent to the upper layer causes the compound (e) and the compound (f) It is considered that the reaction between the epoxy group and the hydroxyl group is accelerated and cross-linking and curing occur.

Method 3 : A base containing a compound (a) containing an epoxy group and a hydroxyl group in the same molecule, a phenylsilanol-based compound (b) and a coloring pigment (c)
(A), and then the epoxy group-containing compound (e), the hydroxyl group-containing compound (f), the phenylsilanol-based compound (b) and the aluminum
A clear coat (D) containing the clear compound (d) is applied, and the base coat (A) and the clear coat are coated with the aluminum chelate compound contained in the coated film of the clear coat (D). (D) A method for forming a multilayer coating film, characterized by accelerating the crosslinking and curing of both coating films.

As the base coat (A) in the method 3, the base coat (A) exemplified in the above method 1 can be similarly used. Further, the epoxy group-containing compound (e) and the hydroxyl group-containing compound (f) in the clear coat (D)
The epoxy group-containing compound (e) and the hydroxyl group-containing compound (f) described in the base coat (C) of the above method 2 can be used in the same manner.

In the clear coat (D), the composition ratio of the epoxy group-containing compound (e) and the hydroxyl group-containing compound (f) is 20 to 60% based on the total weight of these two compounds. The compound (f) is suitably used in an amount of 40 to 80%. The phenylsilanol-based compound (b) is 0.5 to 10 parts, especially 2 to 5 parts, per 100 parts by weight of the total of the compound (e) and the compound (f), and the aluminum chelate compound (d) Is preferably 0.1 to 10 parts, particularly preferably 1 to 5 parts. Further, it is possible to incorporate the above-mentioned coloring pigment (c) into the clear coat (D) within a range that does not impair the transparency. If necessary, a curing catalyst, an ultraviolet absorber, a light-stable Coating additives such as agents can be added.

The clear coat (D) containing the compound (e), the compound (f), the compound (b) and the compound (d) reacts with each other when left at room temperature to increase the viscosity. It is preferable to separate the component containing the compound (f) and the compound (b) from the component containing the compound (d) in advance, and to mix the two components immediately before coating.

The clear coat (D) can be prepared by mixing and dispersing the compound (e), the compound (f), the compound (b) and the compound (d) in an organic solvent, and has a viscosity of 10 to 10. 30 seconds (Ford cup # 4 /
20 ° C), air spray, airless spray,
It can be applied with a spray coating machine such as electrostatic coating. The coating thickness of the cured coating is about 20 to 70 μm.

The multilayer coating film obtained by the method 3 can be formed by carrying out the same method as the method 1 except that the clear coat (B) in the above method 1 is replaced with the clear coat (D). it can. The mechanism of crosslinking and curing of both base coat (A) and clear coat (D) coatings in Method 3 is as follows:
In the clear coat (D) coating, the reaction between the epoxy group and the hydroxyl group in the compound (e) and the compound (f) is promoted by the coexistence of the compound (b) and the compound (d), whereby the cross-linking and curing occur. In the coating film of the coat (A), the interaction between the compound (b) and the compound (d) penetrating from the clear coat (D) coating film adjacent to the upper layer causes the epoxy group in the compound (c) to interact. It is thought that the reaction between the hydroxyl group and the hydroxyl group is accelerated and the resin is crosslinked and cured.

Method 4 : A base coat (C) containing an epoxy group-containing compound (e), a hydroxyl group-containing compound (f), a phenylsilanol-based compound (b) and a coloring pigment (c) is applied. Then, a clear coat (D) containing an epoxy group-containing compound (e), a hydroxyl group-containing compound (f), a phenylsilanol-based compound (b) and an aluminum chelate compound (d) is formed on the uncured coated surface. Paint)
The aluminum chelate compound (d) contained in the clearcoat (D) coating promotes the crosslinking and curing of both the basecoat (C) and clearcoat (D) coatings. This is a method for forming a multilayer coating film.

The base coat (C) described in Method 2 and the clear coat (D) described in Method 3 can be used in Method 4 in the same manner.

The base coat (C) has a viscosity of 10 to 10.
The time can be adjusted to 30 seconds (Ford cup # 4/20 ° C), and the coating can be performed with a spray coating machine such as air spray, airless spray, and electrostatic coating. The coating thickness is 10-40 for the cured coating.
A thickness of about μm is suitable. A single coating of the base coat (A) hardly undergoes crosslinking and curing at a temperature of 100 ° C. or less.

The clear coat (D) can be prepared by mixing and dispersing the above-mentioned components in an organic solvent, adjusting the viscosity to 10 to 30 seconds (for a hood cup # 4/20 ° C.). The coating can be performed by a spray coating machine such as an airless spray or an electrostatic coating, and the thickness of the coating is suitably about 20 to 70 μm as a cured coating.

The multilayer coating film obtained by the method 4 is obtained by replacing the base coat (A) and the clear coat (B) of the above method 1 with the base coat (C) and the clear coat (D). Except for the above, it can be formed by carrying out in the same manner as in Method 1. Base coat (C) in method 4
The mechanism of cross-linking and curing of both the coating films of the clear coat (D) and the clear coat (D) is that the compound (b) and the compound (d) coexist in the clear coat (D) coating film so that the compound (e) and the compound (f) The reaction between the epoxy group and the hydroxyl group in the inside is accelerated and crosslinked and hardened, and in the basecoat (C) coating film, it penetrates from the compound (b) and the clearcoat (D) coating film adjacent to the upper layer. It is considered that the interaction with the compound (d) promotes the reaction between the epoxy group and the hydroxyl group in the compound (e) and the compound (f), and causes crosslinking and curing.

[0054]

EXAMPLES Examples and comparative examples according to the present invention will be described. All parts and percentages are based on weight, and the thickness of the coating is based on the cured coating.

1. Specimens 1) Coating object An epoxy resin-based cationic electrodeposition paint was applied to a steel sheet surface-treated with zinc phosphate (film thickness 25 μm),
Heat curing for 1 minute, then "L-Gabe AM" (manufactured by Kansai Paint Co., trade name, polyester melamine resin)
Was applied (film thickness 30 μm) and cured by heating at 140 ° C. for 30 minutes.

2) Compound (a1): Epoxy group-containing vinyl monomer (Note 1) 200 parts, 2-hydroxyethyl methacrylate 100 parts, n-butyl acrylate 700
Of xylene and 10 parts of azobisisobutyronitrile were dropped into 1000 parts of xylene and reacted at 110 ° C. to obtain an acrylic resin having an epoxy group and a hydroxyl group in the same molecule having a number average molecular weight of 30,000.

(Note 1) Epoxy group-containing vinyl monomer:
It is a compound represented by the following structural formula.

[0058]

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3) Compound (e1): Epoxy group-containing vinyl monomer (Note 1) 200 parts, styrene 100 parts, n-
A mixture of 700 parts of butyl acrylate and 10 parts of azobisisobutyronitrile was dropped into 1000 parts of xylene and reacted at 110 ° C. to obtain an acrylic resin having an epoxy group having a number average molecular weight of 30,000.

4) Compound (f1): A mixture of 100 parts of 2-hydroxyethyl methacrylate, 300 parts of styrene, 600 parts of n-butyl acrylate and 10 parts of azobisisobutyronitrile was dropped into 1000 parts of xylene. ,
The reaction was carried out at 110 ° C. to obtain an acrylic resin having a number average molecular weight of 30,000 and having a hydroxyl group.

5) Basecoat (A) i): 200 parts of compound (a1), 5 parts of diphenylsilanediol and 15 parts of aluminum flake were mixed with an organic solvent (xylene / toluene = 1/1 weight ratio). ), Having a viscosity of 15
It was adjusted to seconds (for ford cup # 4/20 ° C).

6) Basecoat (C) i): 100 parts of compound (e1), 100 parts of compound (f1)
Parts, diphenylsilanediol 5 parts and aluminum flake 20 parts with an organic solvent (xylene / toluene = 1 /
1 weight ratio) and a viscosity of 15 seconds (for ford cup # 4).
/ 20 ° C).

7) Clearcoat (B) i): 200 parts of compound (a1), 5 parts of diphenylsilanediol, and 2 parts of tris (acetylacetonato) aluminum were mixed with an organic solvent (xylene / toluene = 1/1 weight). ratio)
And a viscosity of 15 seconds (Ford cup # 4/20 ° C)
Was adjusted.

8) Clear coat (D) i): 100 parts of compound (e1), 100 parts of compound (f1)
Part, diphenylsilanediol-5 parts, and tris (acetylacetonato) aluminum 2 parts with an organic solvent (xylene /
(Toluene = 1/1 weight ratio), and the viscosity was adjusted to 15 seconds (for ford cup # 4/20 ° C).

9) Basecoat (E) i): "Soflex No. 650" (trade name, lacquer type one-pack type basecoat, manufactured by Kansai Paint Co., Ltd.). Viscosity 1
5 seconds (Ford cup # 4/20 ° C).

10) Clear coat (F) i): "SOFLEX No. 5000" (manufactured by Kansai Paint Co., Ltd., trade name, two-pack type urethane tank rear coat). Viscosity 15
Seconds (Ford cup # 4/20 ° C).

2. EXAMPLES AND COMPARATIVE EXAMPLES After preparing these basecoats and clearcoats, they were allowed to stand at room temperature for 5 hours, and then the basecoats were air-sprayed on the object to be coated to a thickness of 25 μm. After coating, the coating film was left at room temperature for 3 minutes, a clear coat was applied to the coating surface by air spray to a thickness of 40 μm, and left at room temperature for 3 minutes. The coatings were hardened at the same time by forced drying for minutes.

Table 1 shows the results of these coating steps and the performance test of the obtained multilayer coating film.

[0069]

[Table 1]

The test method in Table 1 is as follows.

Adhesion: Cut with a cutter knife so as to reach the substrate, and cut a 2 mm × 2 mm
Make 0, stick the adhesive cellophane tape on the painted surface,
The coated surface after sharply peeling it off at 0 ° C. was observed. ○
Indicates that no peeling of the painted film was observed, and Δ indicates 1-2.
X indicates that 21 pieces were peeled, and x indicates that at least 21 pieces were peeled. Water resistance: The coated surface was observed after immersing the test coated plate in deionized water at 40 ° C. for 48 hours. The appearance is the result of visually evaluating the coated surface after immersion. ○ indicates no change, Δ indicates occurrence of gloss, and × indicates occurrence of blister. Adhesion is the result of performing a gobang-like adhesion test in the same manner as described above after drying the coated surface at 20 ° C. for 24 hours after immersion.

Claims (5)

[Claims] 1. A base coat (A) containing a compound (a) containing an epoxy group and a hydroxyl group in the same molecule, a phenylsilanol compound (b) and a coloring pigment (c). Then, on the uncured coated surface, a clear coat containing a compound (a) containing an epoxy group and a hydroxyl group in the same molecule, a phenylsilanol-based compound (b) and an aluminum chelate compound (d) ( B), and the cross-linking and curing of both the base coat (A) and the clear coat (B) are promoted by the aluminum chelate compound contained in the clear coat (B). A method for forming a multilayer coating film, comprising: 2. A base coat (C) containing an epoxy group-containing compound (e), a hydroxyl group-containing compound (f), a phenylsilanol compound (b) and a coloring pigment (c), The uncured coated surface is then coated with the above-mentioned clear coat (B), and the base coat (C) and clear coat are formed by the aluminum chelate compound contained in the clear coat (B) coating film. -A method for forming a multilayer coating film, characterized by accelerating the crosslinking and curing of both coating films (B). 3. The above-mentioned base coat (A) is applied, and the epoxy group-containing compound (e), the hydroxyl group-containing compound (f) and the phenylsilanol-based compound (b) are applied to the uncured coated surface. ) And an aluminum chelate compound (d) are coated with a clear coat (D), and the aluminum chelate compound contained in the coating film of the clear coat (D) is used to coat the base coat (A). ) And a clear coat (D). 4. The above base coat (C) is applied, and then the uncured coated surface is applied with the above clear coat (D). A cross-linking curing of both the base coat (C) and the clear coat (D) by the aluminum chelate compound contained in the above-mentioned compound. 5. A phenol-silanol compound represented by the general formula:
Ph _n Si (OH) _4-n (where Ph is a phenyl group,
5. The method for forming a multilayer coating film according to claim 1, wherein _n is an integer of 2 or 3.