JP2008274164A - Metal-feeling coating composition and method for forming laminated coating film using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal-feeling coating composition capable of forming well a metal-feeling coating film with metallic appearance, and to provide a method for forming a laminated coating film using the composition. <P>SOLUTION: The metal-feeling coating composition to be laminated on a to-be-coated object or undercoating film layer is provided, comprising a glittering pigment as metallic flakes obtained by grinding vacuum-deposited metallic film and a cellulosic resin obtained by grafting an acrylic resin; wherein the pigment weight concentration (PWC) of the glittering pigment is 0.1-50% and the cellulosic resin is contained at 7-30 wt.% based on the total resin quantity. The method for forming a laminated coating film comprises the step of forming a metal-feeling coating layer by directly laminating the above metal-feeling coating composition on a to-be-coated object or by forming an undercoating film layer on a to-be-coated object followed by laminating the above metal-feeling coating composition on the resulting object and the step of forming a clear topcoating layer on the metal-feeling coating layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a metal-sensitive coating composition and a method for forming a laminated coating film using the same, and more specifically, to ensure high adhesion with upper and lower coating layers and to have a metal-like appearance on a metal plating surface or the like The present invention relates to a metal-sensitive paint composition capable of forming a coating film having a thickness and a method for forming a laminated coating film using the same.

2. Description of the Related Art Conventionally, a paint containing vapor-deposited aluminum obtained by pulverizing a vapor-deposited aluminum film as a metal piece is known as a metal-tone paint, and is used, for example, for coating automobile interiors, wheel caps, and the like.
Such metallic paints used for interior / exterior coating of automobiles have a unique design with no so-called particle feeling and a large difference in gloss between the highlight area and the shade area.

On the other hand, parts such as automobile parts and parts of electric appliances are known that have a metallic surface glossiness such as a mirror surface instead of the metallic background feeling described above.
In a part having such a metallic appearance, a metal thin film is deposited on the surface by metal plating or metal vapor deposition (see, for example, Patent Document 1).
JP-A-63-272544

However, in the method using metal plating, it is necessary to immerse the entire substrate in a plating bath, the manufacturing process is complicated, and there are various restrictions on equipment. Furthermore, there are disadvantages to recent environmental measures such as the use of heavy metals.
In addition, the method of vapor-depositing a metal has a problem that it is necessary to install a base material in a vacuum or a decompression vessel and cannot be applied to a large base material. In addition, there are limitations in practical use, such as the need for pressure reduction.

  In addition, there was a method of producing an appropriate metal texture with a paint containing only a glitter pigment as a pigment by pulverizing a deposited metal film as a pigment, but the glitter material was not neatly oriented in the coating film. In order to ensure designability, it is necessary to carry out many processes such as extremely reducing the film thickness to be applied at one time to ensure the designability, and to ensure the required film thickness, etc. Because it was sensitive to the environment of the environment, fine adjustment of the paint environment was carried out. Furthermore, as the orientation of the glitter pigment became smooth, the adhesion between the glitter pigment layer and the upper and lower coating layers was reduced.

  The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide a metal-sensitive coating composition that can satisfactorily form a metal-sensitive coating film having a metal-sensitive appearance. Another object of the present invention is to provide a method for forming a laminated coating film using the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by defining the content ratio of a fiber-based resin grafted with an acrylic resin, thereby completing the present invention. It came to do.

That is, the metal-sensitive coating composition of the present invention is a coating composition that is laminated on an object to be coated or an undercoat coating layer and exhibits a metallic appearance,
Including a glittering pigment obtained by pulverizing a vapor-deposited metal film into a metal piece, and a fiber-based resin grafted with an acrylic resin,
The glitter pigment has a pigment weight concentration (PWC) of 0.1 to 50%, and the grafted fiber-based resin is contained in an amount of 7 to 30% based on the total resin amount.

  Moreover, the suitable form of the metal-sensitive coating composition of this invention is characterized by the molecular weight of the said grafted fiber-type resin being 5,000-150,000.

Furthermore, the method for forming a laminated coating film of the present invention is to form a laminated coating film using the metal-sensitive paint composition.
A step of directly laminating the metal-sensitive coating composition on the object to be coated to form a metal-sensitive coating layer, or a layer of the metal-sensitive coating composition after forming an undercoat layer on the object to be coated Forming a metal-sensitive coating layer,
Thereafter, a step of forming a clear overcoat layer on the metal-sensitive coating layer is performed.

  According to the present invention, since the content of the fiber-based resin grafted with the acrylic resin is defined, the metal-sensitive paint composition capable of satisfactorily forming the adhesion performance of the metal-sensitive coating film having a metal-like appearance. And a method for forming a laminated coating film using the same.

  Hereinafter, the metal-sensitive coating composition of the present invention will be described in detail. In the present specification and claims, “%” for concentration, content, filling amount and the like represents a mass percentage unless otherwise specified.

As described above, the metal-sensitive coating composition of the present invention is a coating composition that is laminated on an object to be coated or an undercoat coating film layer and exhibits a metallic appearance. Further, the metal-sensitive coating composition includes a bright pigment obtained by pulverizing a vapor-deposited metal film to form a metal piece, and the pigment weight concentration (PWC) of the bright pigment is 0.1 to 50%. Furthermore, the metal-sensitive paint composition contains a fiber-based resin grafted with an acrylic resin in a ratio of 7 to 30% with respect to the total resin amount.
With such a configuration, the coating composition can form a metal-sensitive coating film with good adhesion performance.

Here, the pigment weight concentration (PWC) of the glitter pigment is preferably as high as possible within the above range, and preferably 7 to 20%.
Moreover, it is preferable that the said fibrous resin is also many within the said range, Preferably it is 7 to 30% with respect to resin solid content (total resin amount), More preferably, it is good to contain 10 to 25%.
If the content of the glitter pigment is too large, the fine particles at the time of coating are lowered and the appearance is deteriorated. Conversely, if the content of the glitter pigment is too small, the design of the metallic appearance may be degraded.

The glitter pigment is not particularly limited as long as it is a glitter pigment obtained by pulverizing a deposited metal film into a metal piece.
Such a luster pigment is generally obtained by vapor-depositing a metal film on a base film, peeling the base film, and then pulverizing the vapor-deposited metal film into a metal piece. The thickness of the deposited metal film at this time, that is, the thickness of the metal piece obtained by pulverization is typically preferably about 0.01 to 1 μm. If the thickness is less than 0.01 μm, the background color is easy to transmit, and if it exceeds 1 μm, the metal piece may cause irregular reflection.

In addition, since the glitter pigment is a glitter pigment obtained by pulverizing the deposited metal film to form a metal piece, it is a metal piece having a very thin thickness.
Therefore, as described later, by orienting on the surface, a metal-sensitive coating layer having a flat surface can be formed, and a good metal-like appearance can be brought about.
In contrast, metal flakes such as aluminum flakes used in conventional metallic paints are relatively thick and have irregularities on the surface. Therefore, such metal flakes are oriented on the surface. However, the surface is not flat, and a good metallic appearance as in the present invention cannot be obtained.

  As the degree of pulverization of the metal piece, it is typically preferable that the average particle size is about 0.1 μm to 30 μm. If the thickness is less than 0.1 μm, smoothness and uniformity may be lost, and if it exceeds 30 μm, the workability of the coating film may be deteriorated.

  Furthermore, the material of the vapor-deposited metal film is not particularly limited, and examples thereof include metal films such as aluminum, gold, silver, and copper. From the viewpoint of corrosion, it is particularly preferable to use aluminum powder as a bright pigment.

Next, the grafted fiber-based resin preferably has a molecular weight of 5,000 to 150,000.
Since it is such high molecular weight, the structural viscosity of a coating material can be expressed by increasing the compounding quantity in a coating composition. Moreover, since it is a linear polymer, it is difficult to inhibit the orientation of the glitter pigment on the surface. If the molecular weight is less than 5,000, the effect on the viscosity of the paint is small, and if it exceeds 150,000, the workability of the coating film tends to be lowered.

  The metal-sensitive coating composition of the present invention can be prepared by appropriately adding a solvent, a binder resin, an additive, and other fiber-based resins in addition to the glitter pigment and the acrylic resin-grafted fiber-based resin. .

The solvent is selected in consideration of the type of the release agent or topcoat agent used in the production of the glitter pigment, or the base coat of the metallic paint, and examples of the organic solvent include And hydrocarbon solvents such as aromatic hydrocarbon solvents, ester solvents, ketone solvents, alcohol solvents, ether solvents and the like.
In addition, when the luster pigment is obtained as a commercial product such as a paste, a solvent contained in the paste may be included.

As the binder resin, resins generally used as a film-forming resin can be used, and examples thereof include acrylic resins, vinyl chloride-vinyl acetate copolymer resins, urethane resins, polyester resins, and cellulose resins. .
These binder resins can be used together with a fiber-based resin grafted with an acrylic resin.

  Furthermore, the film thickness of the metal-sensitive coating composition of the present invention is not particularly limited, but is preferably 1 to 20 μm from the viewpoint of forming a smooth metal film. More preferably, it is about 1-5 micrometers.

Next, the formation method of the laminated coating film of this invention is demonstrated in detail.
In the method for forming a laminated coating film according to the present invention, the following first and second steps are performed, or the first 'and second steps are performed in forming the laminated coating film using the above-described metal-sensitive coating composition. It is characterized by that.

(First step) The metal-sensitive coating composition is directly laminated on an object to be coated to form a metal-sensitive coating layer.
(1st 'process) After forming an undercoat paint film layer on an article to be coated, the metal-sensitive paint composition is laminated to form a metal-sensitive paint film layer.
(Second step) A clear topcoat layer is formed on the metal-sensitive coating layer.

  By performing such a process, it is possible to form a laminated coating film having good adhesion performance between a metal-sensitive coating film having a metallic appearance and an object to be coated or a coating film. In other words, for example, in the case of performing the first and second steps, a metal-sensitive coating layer containing a glittering pigment formed by pulverizing a deposited metal film into a metal piece between the undercoat coating layer and the clear topcoat layer is provided. When the glitter pigment in the metal-sensitive coating layer is oriented substantially in a plane, the resulting multilayer coating film exhibits a good metal-like appearance.

Here, in the 1st process of the formation method of the lamination coat of the present invention, a dull steel plate, a galvanized steel plate, etc. which processed zinc phosphate are employable as a thing to be coated, for example. Specifically, a fiber-based resin containing a pigment having a pigment weight concentration (PWC) of 0.1 to 50% on the object to be coated and grafted with an acrylic resin with respect to the total resin ratio is 7 to 30. % Of a metallic coating film layer is formed.
Thereby, the laminated coating film which shows the metal-like appearance which a metal plating surface etc. have can be formed on a to-be-coated article with favorable adhesion | attachment performance.

  Moreover, as a lamination | stacking method to a to-be-coated article, a spray coating method, a roll coating method, etc. can be employ | adopted suitably, for example.

On the other hand, the 1 'step of the method for forming a laminated coating film of the present invention is different from the first process in that an undercoat coating film layer is formed on an object to be coated and under a metal-sensitive coating film layer.
Such an undercoat coating film layer may be a clear coating film or a colored coating film. A colored coating film is preferable. Specifically, in the case of a colored coating film, a dark achromatic color such as gray or black is preferable for a metallic luster such as aluminum.
The undercoat coating film layer can be formed using a paint appropriately selected from a water-based type, a solvent type, and a powder paint.
The presence or absence of the undercoat coating layer is preferably selected as appropriate depending on the type of substrate to be coated, the degree of surface irregularities, and the required level of adhesion.

On the other hand, the 2nd process of the formation method of the lamination coat of the present invention is a process of forming a clear top coat layer on the metallic tone paint layer formed in the 1st process or the 1 'process.
As such a clear overcoating layer, a general clear coating film can be used, and further, a so-called cloudy clear coating film imparted with a translucency may be used.
The clear overcoat layer may be formed from a solvent-type paint or a powder paint. As the solvent-type paint, a one-part paint or a two-part resin such as a two-part urethane resin paint may be used.

  Here, in FIG. 1, sectional drawing of one Embodiment of the laminated coating film obtained with the formation method of the laminated coating film of this invention is shown.

As shown in FIG. 1, this laminated coating film is provided with a metal-tone coating film layer 2 between an undercoat coating film layer 1 and a clear top coating layer 3.
Moreover, the thickness of the undercoat coating layer 1 and the metal finish coating layer 2 is thinner than that of the clear coating top coat layer 3, and the metal finish coating layer 2 is formed on the undercoat coating layer 1 and the clear top coating layer 3. In a sandwiched state, it is oriented in a planar shape.
As described above, the glittering pigment obtained by pulverizing the vapor-deposited metal film into a metal piece is oriented in a planar shape, thereby providing a good metallic appearance.

  Although the thickness of the undercoat coating film layer 1 is not specifically limited, As an example, the thickness of about 15-200 micrometers, Preferably about 10-25 micrometers is mentioned. Further, the thickness of the clear topcoat layer 3 is not particularly limited, but an example is a thickness of about 10 to 50 μm, preferably about 25 to 40 μm. The thickness of the metallic tone coating layer 2 is preferably thin, generally 10 μm or less, preferably 5 μm or less.

  In addition, when forming this laminated coating film on metal plates, such as a steel plate, you may form the said laminated coating film after forming a 1st undercoat layer. For example, after the electrodeposition coating is performed on the metal plate, the first undercoat coating film may be formed, and the laminated coating film may be formed thereon.

  EXAMPLES Hereinafter, although a specific Example is given and this invention is demonstrated in detail, this invention is not limited by a following example.

-Preparation of metal-sensitive paint A paint containing aluminum powder obtained by pulverizing an aluminum deposited film was prepared as a metal-sensitive paint.

  In addition, the following were used as a coating material which forms a metal-sensitive coating composition.

(Production Example 1: Production of acrylic resin solution)
A reactor equipped with a thermometer, thermostat, stirrer, reflux condenser and dropping pump was charged with 40 parts by mass of xylene and 21 parts by mass of n-butanol, and the temperature was raised to 110 ° C. while stirring.
Next, while maintaining the same temperature, from 46 parts by weight of methyl methacrylate, 40 parts by weight of ethyl acrylate, 12.5 parts by weight of 2-hydroxyethyl methacrylate, 1.5 parts by weight of acrylic acid and 0.3 parts by weight of azobisisobutylnitrile 100.3 parts by mass of the resulting mixture was added dropwise at a constant rate over 3 hours using a dropping pump. After completion of the dropwise addition, the temperature was kept at 110 ° C. for 1 hour and stirring was continued.
Thereafter, 0.7 parts by mass of an additional catalyst azobisdimethylvaleronitrile dissolved in 14 parts by mass of xylene was dropped at a constant rate over 1 hour. After the completion of dropping, the temperature was maintained at 110 ° C. for 1 hour, and then the reaction was terminated by cooling.
Next, 24 parts by mass of xylene was added to obtain an acrylic resin solution having a nonvolatile content of 50%. The obtained acrylic resin had a hydroxyl value of 54 mgKOH / g, an acid value of 12 mgKOH / g, and a mass average molecular weight of 65,000.

(Production Example 2: Production of CAB-grafted acrylic resin solution)
To a reactor equipped with a thermometer, thermostat, stirrer, reflux condenser and dropping pump, 4.2 parts by mass of toluene, 2.8 parts by mass of 2-butoxyethyl acetate and CAB-551-0.01 (trade name, 7 parts by weight of cellulose acetate butyrate (hereinafter may be abbreviated as “CAB”, mass average molecular weight 5,000) manufactured by Eastman Chemical Products Co., Ltd., and about 1 in a nitrogen gas atmosphere Heated to 100 ° C. over time. After confirming that the CAB was completely dissolved after the temperature reached 100 ° C., 0.6 part by mass of 2-hydroxyethyl methacrylate, 0.05 part by mass of acrylic acid, 1 part by mass of styrene, 1 part by mass of methyl methacrylate, 2. 7.6 parts by mass of a monomer mixture composed of 35 parts by mass, 2.5 parts by mass of xylene and 0.1 parts by mass of benzoyl peroxide was dropped into the CAB solution over 3 hours. 30 minutes after the completion of dropping, 0.025 parts by mass of azobisisobutyronitrile was added, and the mixture was kept at 100 ° C. for 2 hours under a nitrogen atmosphere to obtain a CAB graft acrylic resin solution (A1) having a solid content of 55%. It was.

  Except for the formulation shown in Table 2, the same operations as in Production Example 2 were repeated to obtain CAB graft acrylic resin solutions (A2) to (A6). Table 1 also shows the CAB amount, graft acrylic amount, and solid content of the obtained CAB graft acrylic resin solutions (A1) to (A6) together with Production Example 2.

Example 1
(1) Metallic paint 116 parts by mass of the acrylic resin solution obtained in Production Example 1, 22 parts by mass of the CAB graft acrylic resin solution (A1) obtained in Production Example 2, “Metacene Slurry 70-0010” (trade name, Ciba Made by Specialty Chemicals, aluminum powder slurry obtained by pulverizing a deposited aluminum film, average particle size 13 μm, thickness 0.05 μm, aluminum powder content 10%) 200 parts by mass and “Uban 28-60” (product) Name (“Uban” is a registered trademark), 50 parts by mass of Mitsui Chemicals, melamine resin, solid content 60%, butyl acetate / xylene / “Swazole 1000” (trade name, manufactured by Cosmo Oil Co., Ltd., aroma Group hydrocarbon solvent) = 50/40/10 mixed solvent prepared to a viscosity of 11 seconds (Ford Cup # 4, 20 ° C.) (X1) was obtained.

(2) Formation of multilayer coating film A cationic electrodeposition paint (trade name “NT200”, a cation type electrodeposition paint manufactured by Kansai Paint Co., Ltd.) is dried on a 0.8 mm thick, 70 mm × 150 mm thick dull steel sheet treated with zinc phosphate. After electrodeposition coating so that the film thickness was 20 μm, it was baked at 160 ° C. for 30 minutes. Thereafter, a gray intermediate coat (trade name: KPX-70) manufactured by Kansai Paint Co., Ltd. was applied at 30 μm and baked at 140 ° C. for 30 minutes.

Next, a laminated coating film composed of a first layer (metal-sensitive paint composition) and a second layer (clear clear coating layer) was formed.
The first layer was spray-coated so that the dry film thickness was 3 to 6 μm, and the second layer was spray-coated so that the dry film thickness was 30 μm. Then, it baked for 30 minutes at 140 degreeC, and formed the laminated coating film.
In addition, the solvent type clear (Brand name "Lugabake M90", the acrylic melamine type paint by Kansai Paint) was used for the coating material for the 2nd layer.

(Examples 2-5, Comparative Examples 1 and 2)
Except for the formulation shown in Table 2, the same operations as in Example 1 were repeated to obtain metal-sensitive paints (X2) to (X7). Moreover, the laminated coating film was formed.

(Performance evaluation)
About the obtained laminated coating film of Examples 1-5 and Comparative Examples 1 and 2, the glossiness, the metallic appearance, and the adhesiveness were evaluated as follows.

(1) Glossiness Evaluation was made according to the following criteria.
○: Shiny.
Δ: Low gloss.
X: There is no gloss.

(2) Metallic appearance Evaluation was made with the naked eye according to the following criteria.
○: The contrast between the highlight portion and the shade portion is large.
(Triangle | delta): The contrast of a highlight part and a shade part is small.
X: There is unevenness and there is no metallic feeling.

(3) Adhesiveness The coating film is drawn with a cutter knife (specified in 7.2 (2) (e) of JIS K 5400) at 11 mm vertical and horizontal parallel lines that reach the coating substrate at intervals of 2 mm. A cellophane tape (as defined in JIS Z 1522) was brought into close contact with the substrate-like coating film and peeled off at a stretch, and the number of substrate substrates in which 100 coating films remained was measured.

From Table 3, the laminated coating film obtained using the metal-sensitive paint composition which is an example of the present invention uses a fiber-based resin grafted with an acrylic resin. It can be seen that there is no decline in sex. It can also be seen that a uniform metallic appearance is also imparted.
On the other hand, in the laminated coating films obtained in Comparative Examples 1 to 4 corresponding to the conventional products, it is understood that when the deposited metal is increased, the adhesion between the deposited metal layer and its upper and lower layers is lowered.

According to the present invention, although it is not as strong as mirror gloss, it can give an article with a metallic appearance having a strong gloss compared to conventional silver coating by forming a coating film.
Therefore, it is possible to impart a metallic appearance stronger than that of conventional silver coating to automobile parts such as handles and wheels, automobile bodies, etc., or electrical appliances and other articles in a simple process.

It is sectional drawing which shows an example of the laminated coating film using the metal-sensitive coating composition of this invention.

Explanation of symbols

1 ... Undercoat layer 2 ... Metal-sensitive coating layer 3 ... Clear topcoat layer

Claims (7)

It is a coating composition that is laminated on an article to be coated or an undercoat coating layer and exhibits a metallic appearance,
Including a glittering pigment obtained by pulverizing a vapor-deposited metal film into a metal piece, and a fiber-based resin grafted with an acrylic resin,
A metal characterized in that the pigment weight concentration (PWC) of the glitter pigment is 0.1 to 50%, and the grafted fiber-based resin is contained in an amount of 7 to 30% based on the total resin amount. Sensitive paint composition.   2. The metal-sensitive coating composition according to claim 1, wherein the grafted fiber-based resin has a molecular weight of 5,000 to 150,000.   Thickness is 1-20 micrometers, The metal-sensitive paint composition of Claim 1 or 2 characterized by the above-mentioned.   The metallic paint composition according to any one of claims 1 to 3, wherein the glitter pigment is aluminum powder.   The metal-sensitive paint composition according to any one of claims 1 to 4, wherein a thickness of the metal piece constituting the glitter pigment is 0.01 to 1 µm.   The metal-sensitive paint composition according to any one of claims 1 to 5, wherein an average particle diameter of metal pieces constituting the glitter pigment is 0.1 to 30 µm. In forming a laminated coating film using the metal-sensitive paint composition according to any one of claims 1 to 6,
A step of directly laminating the metal-sensitive coating composition on the object to be coated to form a metal-sensitive coating layer, or a layer of the metal-sensitive coating composition after forming an undercoat layer on the object to be coated Forming a metal-sensitive coating layer,
Then, the process of forming a clear coating layer on this metal-sensitive coating film layer is performed, The formation method of the laminated coating film characterized by the above-mentioned.

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