JP4170806B2 - Multilayer coating film forming method, multilayer coating film and article - Google Patents

Description

【００９１】
表１から、マイクロチタンＭＴ−５００ＨＤ（微粒子酸化チタン）の配合量の増加とともに、シェード部での補色（黄味）が低減する傾向があることが明らかとなった。また、マイクロチタンＭＴ−５００ＨＤを配合しても、ハイライト部での干渉色は、ほとんど阻害されることがなかった。目視による評価でも実施例により得られたものは、シェード部での補色（黄味）が抑制されていることが明らかとなった。
【００９２】
【発明の効果】
本発明の複層塗膜形成方法は、上述の構成よりなるので、干渉色による意匠性を極力阻害することなく、シェード部の補色を抑制することができるものである。従って、自動車及び部品等に好適に適用することによって、シェード部での補色を抑制することができ、新規な塗色を設計できることが示唆された。
【図面の簡単な説明】
【図１】 本発明の複層塗膜の構造を示す断面図の一例を示す図である。
【符号の説明】
１ クリヤー塗膜
２ マイカベース塗膜
３ カラーベース塗膜
４ 中塗り塗膜
５ 下塗り塗膜
６ 基材（鋼板）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a multilayer coating film, a multilayer coating film, and an article.
[0002]
[Prior art]
In order to meet the needs of multicolored top coat colors and needs, the number of pearl coating films formed from paints containing scaly mica pigments is increasing year by year. For example, a white pearl-like or silver pearl-like base coat and clear coat composed of a colored base coat and scaly mica powder coated with titanium oxide are applied with wet-on-wet, and the coating film is simultaneously crosslinked and cured. Has been proposed (for example, see Patent Document 1).
[0003]
Furthermore, there has been proposed a method in which a color base paint containing an organic amide, a glitter material-containing base paint containing a glitter material, and a clear paint are sequentially applied to form a laminated coating film (see, for example, Patent Document 2).
[0004]
However, when a coating film is formed by such a conventional method for forming a multilayer coating film, the interference mica pigment has a pearly luster with respect to light incident from the outside when viewed from the highlight position. Although it appears, there is a problem that, when viewed from the shade position, intense complementary colors are generated and the design properties are lowered.
[0005]
[Patent Document 1]
JP-A-8-164358 (2nd page)
[Patent Document 2]
JP-A-11-114489 (2nd page)
[0006]
[Problems to be solved by the invention]
In view of the above situation, the present invention provides a multilayer coating film forming method and an article having a multilayer coating film capable of suppressing complementary color in a shade portion without hindering the design properties due to interference colors as much as possible. It is intended.
[0007]
[Means for Solving the Problems]
The present invention relates to a method for forming a multilayer coating film in which a color base paint containing a color pigment, a mica base paint containing an interference mica pigment, and a clear paint are sequentially applied onto a substrate on which an undercoat film and an intermediate coat film are formed. The mica base coating contains fine titanium oxide having an average particle diameter of 0.01 to 0.1 μm and having a coating film made of alumina and / or zirconia on the surface.The fine particle titanium oxide is contained in an amount of 0.1 to 10.0 parts by mass with respect to 100 parts by mass of the interference mica pigment in the mica base paint.A method for forming a multi-layer coating film.
[0009]
The present invention is a multilayer coating film formed by the above-described multilayer coating film forming method.
The present invention is also an article characterized by having the multilayer coating film.
Hereinafter, the present invention will be described in detail.
[0010]
The multi-layer coating film forming method of the present invention is such that a color base paint containing a colored pigment, a mica base paint containing an interference mica pigment, and a clear paint are sequentially applied onto a substrate on which an undercoat film and an intermediate coat film are formed. It is a method to do.
[0011]
In the method for forming a multilayer coating film according to the present invention, the mica-based paint contains fine titanium oxide having an average particle diameter of 0.01 to 0.1 μm on the surface of which a film made of alumina and / or zirconia is formed. It is. By including fine particle titanium oxide having a specific average particle diameter on which a film made of alumina and / or zirconia is formed, complementary color in the shade portion can be suppressed.
[0012]
A multi-layer coating film formed by sequentially applying a color base paint containing a colored pigment, a mica base paint containing an interference mica pigment, and a clear paint has dichroism because light interference occurs due to the interference mica pigment. It will be a thing. Therefore, when viewed from the highlight position, interference colors such as silver, yellow, red, blue, and green can be seen depending on the film thickness of the titanium dioxide film. A complementary color of the interference color will be seen. Since the mica base paint in the present invention contains the fine particle titanium oxide, it is possible to suppress complementary colors in the shade portion. The mechanism of the effect of suppressing complementary color is not clear, but it is presumed that light of the wavelength corresponding to the complementary color is scattered and absorbed by the fine titanium oxide contained in the formed mica base coating film. Is done.
[0013]
The fine particle titanium oxide has an average particle size of a lower limit of 0.01 μm and an upper limit of 0.1 μm. When the thickness is less than 0.01 μm, the concealability may be inferior. If it exceeds 0.1 μm, the complementary color at the shade portion may not be sufficiently suppressed, and the interference color by the interference mica pigment may be inhibited. The lower limit is more preferably 0.02 μm, still more preferably 0.03 μm. The upper limit is more preferably 0.07 μm, still more preferably 0.05 μm.
[0014]
The fine particle titanium oxide has a coating film made of alumina and / or zirconia formed on the surface. The method for forming a film made of alumina and / or zirconia on the surface is not particularly limited, and can be performed by a conventionally known surface treatment of titanium oxide. By performing the surface treatment of titanium oxide, the generation of radicals of titanium oxide is suppressed, and the light deterioration resistance is improved.
[0015]
The commercial product of the fine particle titanium oxide is not particularly limited as long as it has an average particle diameter of 0.01 to 0.1 μm on the surface of which a film made of alumina and / or zirconia is formed. MT-500HD (manufactured by Teika), Type TTO-55D (manufactured by Ishihara Sangyo Co., Ltd.) and the like can be mentioned. These may be used alone or in combination of two or more.
[0016]
In the mica base paint, the fine particle titanium oxide is preferably contained in a lower limit of 0.1 part by mass and an upper limit of 10.0 parts by mass with respect to 100 parts by mass of the interference mica pigment in the mica base paint. If the amount is less than 0.1 parts by mass, the complementary color in the shade part may not be sufficiently suppressed. If the amount exceeds 10.0 parts by mass, the whiteness may increase. The lower limit is more preferably 0.5 parts by mass and even more preferably 1.0 part by mass. The upper limit is more preferably 9.0 parts by mass, and even more preferably 7.0 parts by mass.
[0017]
In the mica-based paint, the fine particle titanium oxide is preferably contained at a lower limit of 0.01% by mass and an upper limit of 1.0% by mass in terms of pigment concentration (PWC). If it is less than 0.01% by mass, the complementary color in the shade part may not be sufficiently suppressed, and if it exceeds 1.0% by mass, the whiteness may increase. The lower limit is more preferably 0.02% by mass, still more preferably 0.03% by mass. The upper limit is more preferably 0.9% by mass, and still more preferably 0.8% by mass.
[0018]
In the multi-layer coating film forming method of the present invention, first, as a first step, a color base paint containing a color pigment is applied on a substrate on which an undercoat film and an intermediate coat film are formed, thereby forming a color base film. To do.
[0019]
The color base paint includes a color pigment, a film-forming resin and a curing agent, and an organic amide and crosslinked resin particles as necessary.
Examples of the color pigment contained in the color base paint include various organic and inorganic color pigments and extender pigments.
[0020]
Examples of the colored pigment include organic azo lake pigments, insoluble azo pigments, condensed azo pigments, phthalocyanine pigments, indigo pigments, perinone pigments, perylene pigments, dioxazine pigments, quinacridone pigments, and isoindoids. For example, calcium carbonate, barium sulfate, clay, talc, and the like are used as inorganic pigments such as linone pigments, metal complex pigments, inorganic chrome yellow, yellow iron oxide, bengara, carbon black, titanium dioxide, and the like.
[0021]
A white pigment such as titanium dioxide is mainly used as the color pigment of the color base paint. The content of the white pigment is preferably contained at a pigment concentration (PWC) having a lower limit of 30% by mass and an upper limit of 75% by mass. When it is less than 30% by mass, the base concealing property is deteriorated, and when it exceeds 75% by mass, the appearance is deteriorated. The lower limit is more preferably 45% by mass, and the upper limit is more preferably 65% by mass. By including the white pigment in the above range, a so-called white color base coating film having a Munsell value of N7 to N9.5 can be formed.
[0022]
Examples of the film-forming resin and curing agent for the color base paint include coating resins such as acrylic resins, polyester resins, alkyd resins, and fluorine resins, and curing agents such as amino resins and / or block polyisocyanate compounds. Used. These preferable solid contents in the paint are in the range of 30 to 70% by mass during production and 10 to 50% by mass during application.
[0023]
Examples of the organic amide contained in the color base paint include those generally known as viscosity control agents for imparting thixotropy. Specific examples include fatty acid amides, and those available as a commercial product are known in powder form and paste form. This paste is generally diluted with a solvent such as xylene or alcohol.
[0024]
Examples of the fatty acid amide include diamide and polyamide. Diamide is a compound obtained by reacting a diamine with a hydroxyl group-containing fatty acid. Polyamide is a compound obtained by reacting a polybasic carboxylic acid, a diamine, and a hydroxyl group-containing fatty acid. The number average molecular weight (Mn) is generally 1000 to 2000.
[0025]
The content of the organic amide in the color base paint is preferably 0.1 parts by mass and 10 parts by mass with respect to 100 parts by mass of the resin solid content in the paint. If it is less than 0.1 parts by mass, the appearance of the coating film such as gloss and color may be deteriorated. If it exceeds 10 parts by mass, the coating film may become rough and the coating film performance may deteriorate. The lower limit is more preferably 0.3 parts by mass, and still more preferably 0.5 parts by mass. The upper limit is more preferably 5 parts by mass, and still more preferably 3 parts by mass.
[0026]
On the other hand, as the crosslinked resin particles used in the color base paint in the present invention, those generally known as viscosity control agents can be used. For example, resin particles called NAD (NonAqueous Dispersion) can be used. Examples of this include resin particles used in NAD paints described in Coloring Materials, Vol. 48 (1975), pages 28 to 34. Moreover, the polymerizable resin particles disclosed in JP-A-53-133236 can be used as the crosslinked resin particles in the present invention.
[0027]
Among the crosslinked resin particles, those which do not affect the gloss and color developability when formed into a coating film are preferable, and non-crosslinked or crosslinked resins or particles utilizing the interaction of polar groups are more preferable. Most preferred is one obtained by polymerizing a monomer in the presence of a polyester resin having a zwitterionic group.
[0028]
Examples of such crosslinked resin particles include those that are insoluble in an organic solvent and have an average particle size of 0.02 to 0.5 μm. When it exceeds 0.5 μm, the stability is lowered. In addition, the crosslinked resin particles include a resin having an emulsifying ability such as an alkyd resin or a polyester resin synthesized with a monomer having a zwitterionic group in the molecule as one of the polyhydric alcohol components, and a polymerization initiator. Below, what is obtained by emulsion-polymerizing an ethylenically unsaturated monomer in an aqueous medium is preferable.
[0029]
The crosslinked resin particles obtained by the emulsion polymerization method are generally contained in an emulsion resin, do not contain a low-molecular emulsifier or protective colloid that degrades performance when formed into a coating film, and two or more in the molecule. Since it is crosslinked by copolymerizing a monomer having an ethylenically unsaturated group capable of radical polymerization, the water resistance, solvent resistance and gloss of the coating film are excellent.
[0030]
The content of the crosslinked resin particles in the color base paint is preferably 2 parts by mass and 20 parts by mass with respect to 100 parts by mass of the resin solid content. If the content of the crosslinked resin particles is too small, the appearance of the coating film such as gloss and color may be deteriorated. Moreover, when there is too much content of a crosslinked resin particle, rough skin will arise in a coating film and coating film performance may fall. The lower limit is more preferably 4 parts by mass, and still more preferably 6 parts by mass. The upper limit is more preferably 17 parts by mass and even more preferably 15 parts by mass.
[0031]
In the present invention, when the cross-linked resin particles are contained in the color base paint, the blending ratio of the organic amide and the cross-linked resin particles is 1/50 to 1.5 / 1 in terms of the solid content of the organic amide / cross-linked resin particles. It is preferable that there is, and more preferably 1/20 to 1/1. When the amount of the organic amide in the blending ratio is small, glossiness or color feeling in the appearance of the coating film may be lowered. Moreover, when there is too much quantity of the organic amide in a compounding ratio, coating-film performance may fall.
[0032]
Further, the total content of the organic amide and the crosslinked resin particles is preferably 2 parts by mass and 30 parts by mass with respect to 100 parts by mass of the resin solid content in the color base paint. If it is less than 2 parts by mass, the gloss and color sensation in the appearance of the coating film may be reduced. If it exceeds 30 parts by mass, the coating film may be roughened and the coating film performance may be reduced. The lower limit is more preferably 4 parts by mass, and still more preferably 6 parts by mass. The upper limit is more preferably 20 parts by mass, and still more preferably 16 parts by mass.
[0033]
In the present invention, the color base paint may contain other additives as desired. Examples of the additive include surface conditioners such as silicone and organic polymers, ultraviolet absorbers, hindered amines, hindered phenols, and the like.
[0034]
The total pigment concentration (PWC) in the color base paint is preferably a lower limit of 3% by mass and an upper limit of 70% by mass. When it exceeds 70% by mass, the appearance of the coating film is deteriorated. The lower limit is more preferably 4% by mass, and still more preferably 5% by mass. The upper limit is more preferably 65% by mass, and still more preferably 60% by mass.
[0035]
In general, the color base paint used in the present invention is preferably a solution type, and any organic solvent type, aqueous type (water-soluble, water-dispersible, emulsion) or non-water-dispersed type may be used as long as it is a solution type. .
[0036]
The method for producing the coating composition used in the present invention is not particularly limited, including those described later, and is a method well known to those skilled in the art such as kneading and dispersing a compound such as a pigment using a kneader or a roll. Can be used.
[0037]
When the color base paint is applied on the substrate on which the undercoat film and the intermediate coat film are formed, it is applied in multiple stages by air electrostatic spray coating, preferably in two stages, in order to improve the design. Or, a combination of air electrostatic spray coating and a rotary atomizing electrostatic coating machine known as "μμ (micro micro) bell", "μ (micro) bell", "meta bell", etc. A coating film can be formed by the method.
[0038]
In the present invention, the thickness of the coating film applied with the color base paint varies depending on the desired application, but in many cases, 30 to 60 μm is useful. If the thickness is less than 30 μm, the underlying layer cannot be concealed and the film may be cut off. If the thickness exceeds 60 μm, the sharpness may be deteriorated, or defects such as unevenness and flow may occur during painting. Moreover, the dry film thickness of a color base coating film is 20-40 micrometers normally. If the thickness is less than 20 μm, there may be a problem in smoothness and concealment, and if it exceeds 40 μm, problems such as unevenness and flow may occur.
[0039]
After the color base paint is applied as described above, the mica base paint can be applied in an uncured state. However, when the color base coating film is cured, the curing temperature is a lower limit of 100 ° C. and an upper limit of 180 ° C. It is preferable that If it is less than 100 ° C, curing may not be sufficient, and if it exceeds 180 ° C, the coating film may become hard and brittle. The lower limit is more preferably 120 ° C., and the upper limit is more preferably 160 ° C. By setting in such a range, a cured coating film having a high degree of crosslinking can be obtained. Although hardening time changes with hardening temperature, 10 to 30 minutes are suitable at 120-160 degreeC.
[0040]
In the multilayer coating film forming method of the present invention, as a second step, a mica base coating film containing an interference mica pigment is applied on the color base coating film formed as described above to form a mica base coating film. Is.
[0041]
In the multilayer coating film forming method of the present invention, a mica base coating is used for forming a mica base coating film.
The mica-based coating material contains an interference mica pigment, a film-forming resin and a curing agent, and, if necessary, crosslinked resin particles in addition to the above-described fine particle titanium oxide.
[0042]
The interference mica pigment is obtained by coating the surface of the mica pigment with a metal oxide, and has various interference colors depending on the thickness of the coating layer.
Examples of the interference mica pigment include those usually used in metallic paints. Although the shape is not particularly limited, for example, a scaly shape is preferable, and the average particle diameter (D₅₀) Of 2 to 50 μm and a thickness of 0.1 to 3 μm are suitable.
[0043]
The interference mica pigment is formed on the surface of the mica pigment with TiO.₂, SnO₂, ZrO₂, Fe₂O₃ZnO₂, Cr₂O₃, V₂O₅And mica pigments coated with metal oxides such as their hydrates, which have a pearly foil shape, metal-like and iridescent effect, and also provide a color feeling that the metal oxide species and the thickness of the coating layer exhibit. . Especially, what coat | covered metal oxides, such as titanium dioxide and iron oxide, uniformly is used suitably.
[0044]
For example, “Iriodin Ultra 7235 W2” (trade name) manufactured by Merck Japan as an interference mica pigment having a green interference color, and “Iriodin Ultra 7225 W2” (product by Merck Japan) as an interference mica having a blue interference color. Name), an interference mica having an interference color of yellow, “Iriodin Ultra 7205 W2” (trade name) manufactured by Merck Japan Ltd. can be exemplified. In addition, alumina flakes having interference light can also be used as the interference mica pigment.
[0045]
In the mica base paint, the interference mica pigment has a pigment concentration (PWC) of generally 18.0% by mass or less. If it exceeds 18.0% by mass, the appearance of the coating film may be lowered. The lower limit of the pigment concentration of the interference mica pigment is preferably 0.01% by mass. Further, the upper limit is more preferably 17.0% by mass, and further preferably 16.0% by mass.
[0046]
The mica base paint may contain a mica pigment other than the interference mica pigment. Examples of mica pigments other than the above-mentioned interference mica pigment include, for example, “Iriodin 103 W2” (trade name) manufactured by Merck Japan, “Pearl Grace SME 90-9” (trade name) manufactured by Nippon Koken Co., Ltd. Can be mentioned.
[0047]
The film-forming resin contained in the mica base paint is not particularly limited, and for example, those mentioned in the description of the color base paint can be used. When the mica-based paint is used as a water-based paint, a film-forming resin specifically described in US Pat. Nos. 5,151,125 and 5,183,504 can be used.
[0048]
Moreover, it is preferable that the said mica base coating material is added with crosslinked resin particles in order to ensure coating workability. As the crosslinked resin particles used in the mica base paint, for example, those mentioned in the description of the color base paint can be used.
[0049]
The addition amount of the crosslinked resin particles in the mica-based paint is preferably 0.01 parts by mass and 10 parts by mass with respect to 100 parts by mass of the resin solid content of the coating composition. If the amount is less than 0.1 parts by mass, the viscosity control effect cannot be obtained, which may cause familiarity and inversion between layers. If it exceeds 10 parts by mass, the appearance may be deteriorated. The lower limit is more preferably 0.02 parts by mass, and still more preferably 0.03 parts by mass. The upper limit is more preferably 8 parts by mass, and still more preferably 6 parts by mass.
[0050]
The total solid content of the mica-based paint is preferably 10% by mass as the lower limit and 60% by mass as the upper limit. The lower limit is more preferably 15% by mass, and the upper limit is more preferably 55% by mass.
[0051]
The paint form of the mica base paint used in the present invention may be any of an organic solvent type, an aqueous type (water-soluble, water-dispersible, emulsion), and a non-water-dispersed type. If necessary, a curing catalyst, an ultraviolet absorber, Antioxidants, surface preparation agents, and the like can be used.
[0052]
The mica base coating is prepared by applying the mica base coating on the cured color base coating formed as described above, or by wet-on-wet coating on the uncured color base coating. It can be formed by painting a paint.
[0053]
Similar to the color base paint, the mica base paint can be applied by a rotary atomizing electrostatic coating machine such as μμ bell or μ bell, and the formed mica base coating film has a dry film thickness of 10 It is preferable that it is -30 micrometers.
[0054]
In the multilayer coating film forming method of the present invention, as a third step, a clear coating film is formed by coating a clear coating material on the mica base coating film formed as described above.
The clear paint contains a film-forming resin and a curing agent.
[0055]
The film-forming resin of the clear coating is not particularly limited, and for example, a film-forming resin such as an acrylic resin, a polyester resin, an epoxy resin, and a urethane resin can be used. These include an amino resin and / or Used in combination with a curing agent such as a blocked isocyanate resin. From the viewpoint of transparency or acid etching resistance, a combination of an acrylic resin and / or a polyester resin and an amino resin, or an acrylic resin and / or a polyester resin having a carboxylic acid / epoxy curing system can be used.
[0056]
The solid content in the clear coating is preferably a lower limit of 20% by mass and an upper limit of 60% by mass, the lower limit is more preferably 35% by mass, and the upper limit is more preferably 55% by mass. preferable. Further, the solid content at the time of coating is preferably a lower limit of 10% by mass and an upper limit of 50% by mass, the lower limit is more preferably 20% by mass, and the upper limit is more preferably 50% by mass. preferable.
[0057]
The above clear coating is usually applied in an uncured state after the mica base coating is applied, so that a coating film is formed by so-called wet-on-wet. Therefore, it is preferable to contain the above-mentioned crosslinked resin particles.
[0058]
The content of the crosslinked resin particles in the clear coating is preferably 0.01 parts by mass and 10 parts by mass with respect to 100 parts by mass of the resin solid content of the clear coating composition. If it is less than 0.1 parts by mass, the viscosity control effect cannot be obtained, which causes problems such as sagging. If it exceeds 10 parts by mass, the appearance may be deteriorated. The lower limit is more preferably 0.02 parts by mass, and still more preferably 0.03 parts by mass. The upper limit is more preferably 8 parts by mass, and still more preferably 6 parts by mass.
[0059]
The clear paint used in the present invention may be any of organic solvent type, aqueous type (water-soluble, water-dispersible, emulsion), non-water-dispersed type, and powder type, and if necessary, a curing catalyst, surface A preparation agent or the like can be used.
[0060]
The clear coating film is usually formed by applying a clear coating material by wet-on-wet coating on the uncured mica base coating film formed as described above. In addition, you may apply | coat on the hardened mica base coating film.
[0061]
The clear coating film is formed in order to smooth and protect the unevenness, flickering, and the like caused by the bright pigment contained in the mica base coating film. Specifically, as a coating method, it is preferable to form a coating film by the above-described rotary atomizing electrostatic coater such as μμ bell or μbell.
[0062]
As for the dry film thickness of the clear coating film formed with the said clear coating material, generally a minimum of 10 micrometers and an upper limit of 70 micrometers are preferable. If the thickness is less than 10 μm, the unevenness of the base may not be concealed, and if it exceeds 70 μm, problems such as cracking and sagging may occur during coating. The lower limit is more preferably 20 μm, and the upper limit is more preferably 50 μm.
[0063]
After the application of the clear coating film, the curing temperature for curing the coating film is preferably a lower limit of 100 ° C. and an upper limit of 180 ° C. If it is less than 100 ° C, curing may not be sufficient, and if it exceeds 180 ° C, the coating film may be hard and brittle. The lower limit is more preferably 120 ° C, and still more preferably 160 ° C. Although hardening time changes with hardening temperature, 10 to 30 minutes are suitable at 120 to 160 degreeC.
[0064]
The laminated coating film may be cured by 3 coats and 1 bake. In this case, when the color base paint and the mica base paint are used as a water-based paint, in order to obtain a good finished paint film, the paint film is heated at 60 to 100 ° C. for 2 to 10 minutes after being formed. It is desirable to keep it.
[0065]
The film thickness of the multilayer coating film formed in the present invention is usually a lower limit of 30 μm and an upper limit of 300 μm. If it is less than 30 μm, the strength of the film itself may be reduced, and if it exceeds 300 μm, film properties such as a cooling cycle may be reduced. The lower limit is more preferably 50 μm, and the upper limit is more preferably 250 μm.
[0066]
In the multilayer coating film forming method of the present invention, the article to be coated is a substrate on which an undercoat film and an intermediate coat film are formed.
The substrate is not particularly limited. For example, it can be advantageously used for metal surfaces, castings, such as wood, metal, glass, cloth, plastics, foams, etc. On the other hand, it can be particularly preferably used.
[0067]
It does not specifically limit as said metal product, For example, the alloy containing these metals, such as iron, copper, aluminum, tin, zinc, can be mentioned. Specific examples include automobile bodies and parts such as passenger cars, trucks, motorcycles, and buses. These metals are particularly preferably those subjected to chemical conversion treatment with phosphate, chromate or the like in advance.
[0068]
In the method for forming a multilayer coating film of the present invention, as the electrodeposition paint for forming the undercoat film, a cation type and an anion type can be used, and the cationic electrodeposition coating composition is excellent in corrosion resistance. Give a membrane.
[0069]
In the method for forming a multi-layer coating film of the present invention, the intermediate coating film conceals underlying defects, ensures surface smoothness after top coating (improves appearance), and physical properties of the coating film (impact resistance, chipping resistance). Etc.). In order to form this intermediate coating film, an intermediate coating composition is used, and this intermediate coating composition contains various organic and inorganic color pigments, extender pigments, a film-forming resin, a curing agent, and the like.
[0070]
Examples of the color pigment used in the intermediate coating material include those described in the above color base coating material. Further, flat pigments such as aluminum powder and graphite powder may be added.
[0071]
As the above intermediate coating material, a gray intermediate coating material mainly containing carbon black and titanium dioxide is used. Furthermore, a so-called color intermediate coating composition in which set gray or various colored pigments are combined can also be used.
[0072]
The film-forming resin used for the intermediate coating is not particularly limited, and for example, those described in the above color base coating are used. From the viewpoint of pigment dispersibility and workability, a combination of an alkyd resin and / or a polyester resin and an amino resin is preferable.
[0073]
After the intermediate coating material is applied onto the substrate on which the undercoat coating film is formed, it can be used even in an uncured state. However, when the intermediate coating film is cured, the curing temperature has a lower limit of 100. It is preferable that it is 0 degreeC and an upper limit is 180 degreeC. If it is less than 100 ° C, curing may not be sufficient, and if it exceeds 180 ° C, the coating film may be hard and brittle. The lower limit is more preferably 120 ° C., and the upper limit is more preferably 160 ° C. Thereby, a cured coating film having a high degree of crosslinking can be obtained. The curing time varies depending on the curing temperature, but 10 to 30 minutes at 120 to 160 ° C. is appropriate.
[0074]
The multilayer coating film formed by the above-described multilayer coating film forming method can suppress the complementary color of the shade portion without hindering the design property due to the interference color as much as possible. Such a multilayer coating film is also one aspect of the present invention. An article having the multilayer coating film is also one aspect of the present invention.
[0075]
The multi-layer coating film forming method of the present invention uses a mica base paint containing fine particle titanium oxide having an average particle diameter of 0.01 to 0.1 μm on which a film made of alumina and / or zirconia is formed. For this reason, it is possible to form a multilayer coating film capable of suppressing the complementary color of the shade portion without hindering the design property due to the interference color as much as possible. Therefore, the multilayer coating film forming method is a method capable of forming a multilayer coating film having an excellent appearance and the like, and can be suitably applied to automobile bodies and parts.
[0076]
【Example】
EXAMPLES Hereinafter, although an Example is hung up and demonstrated in more detail, this invention is not limited only to these Examples. In the examples, “parts” means “parts by mass” unless otherwise specified.
[0077]
Production Example 1 Production of color base paint
A white color base paint was produced with the formulation shown below.
Titanium R-61 21.00 parts
(Titanium dioxide manufactured by Sakai Chemical Industry Co., Ltd.)
TAROX synthetic iron oxide LL-XLO 0.10 parts
(Iron oxide manufactured by Toyo Ink)
B-34 6.00 parts
(Barium sulfate manufactured by Sakai Chemical Industry Co., Ltd.)
Thermosetting acrylic resin 30.30 parts
(Nippon Paint Co., Ltd., hydroxyl value 45, acid value 15, number average molecular weight 21000, solid content 50%)
Uban 20N60 10.80 parts
(Butylated melamine resin manufactured by Mitsui Chemicals, solid content 60%)
Acrylic surface conditioner 0.20 parts
Cross-linked resin particles 16.00 parts
(Nippon Paint Co., Ltd. structural viscosity imparting agent, solid content 20%)
n-butanol 2.70 parts
Xylol 4.00 parts
91.10 copies in total
[0078]
Production Example 2 Production of mica base paint 1
A mica base 1 paint was produced with the following composition (PWC 8%, containing 1.25 parts of fine titanium oxide with respect to 100 parts of interference mica pigment).
Silacic T60-10WNT Crystal Silver 1.34 parts
(Interference mica pigment manufactured by Merck Japan Ltd., average particle size 18 μm)
SILALIK T60-23WNT Galaxy Blue 1.34 parts
(Interference mica pigment manufactured by Merck Japan Ltd., average particle size 18 μm)
Micro titanium MT-500HD 0.03 parts
(Taica fine particle titanium oxide, average particle size 0.03 μm)
43.00 parts thermosetting acrylic resin
(Nippon Paint Co., Ltd., hydroxyl value 45, acid value 15, number average molecular weight 21000, solid content 50%)
Yuban 20N60 15.40 parts
(Butylated melamine resin manufactured by Mitsui Chemicals, solid content 60%)
SIPERNAT 22LS 1.54 parts
(Degussa colloidal silica, solid content 20%)
Acrylic surface conditioner 0.20 parts
Cross-linked resin particles 14.00 parts
(Nippon Paint Co., Ltd. structural viscosity imparting agent, solid content 20%)
4.20 parts of n-butanol
Xylol 4.13 parts
12.82 parts of toluene
Total 98.00 copies
[0079]
Production Example 3 Production of mica base paint 2
Mica base paint 2 was prepared in the same manner as in Production Example 2 except that the amount of microtitanium MT-500HD was changed to 0.09 part.
[0080]
Production Example 4 Production of mica base paint 3
Mica base paint 3 was prepared in the same manner as in Production Example 2, except that the amount of microtitanium MT-500HD was changed to 0.15 part.
[0081]
Production Example 5 Production of mica base paint 4
A mica base paint 4 was prepared in the same manner as in Production Example 2, except that the microtitanium MT-500HD was not blended.
[0082]
Example 1 Method for forming a multilayer coating film
Cathodic electrodeposition paint “Power Top U-50” (manufactured by Nippon Paint Co., Ltd.) is electrodeposited onto a 0.8 cm thick, 20 cm × 30 cm thick steel plate treated with zinc phosphate so that the dry film thickness is 20 μm. And baked at 160 ° C. for 30 minutes. Next, on the obtained electrodeposition coating film, a gray intermediate coating “Orga P-2 Gray” (manufactured by Nippon Paint Co., Ltd., polyester / melamine resin-based coating) is applied so that the dry film thickness becomes 30 μm. Spray coating was performed, and an intermediate coating film was baked at 140 ° C. for 20 minutes.
[0083]
On the obtained intermediate coating film, the color base coating material of Production Example 1 was electrostatically applied so that the dry film thickness was 30 μm, and baked at 140 ° C. for 20 minutes to prepare a color base coating film.
[0084]
Further, the mica base paint 1 of Production Example 2 was similarly electrostatically coated so that the dry film thickness was 15 μm. Next, after setting for 7 minutes, with a wet-on-wet, clear paint "Super Lac O-1810 Clear" (manufactured by Nippon Paint Co., Ltd., acid / epoxy curable acrylic resin paint) with a dry film thickness of 30 μm A rotary atomization type electrostatic coating was applied. An evaluation coating film was prepared by baking at 140 ° C. for 20 minutes.
[0085]
Example 2
A coating film for evaluation was prepared in the same manner as in Example 1 except that the mica base paint 2 was used instead of the mica base paint 1.
[0086]
Example 3
A coating film for evaluation was prepared in the same manner as in Example 1 except that the mica base paint 3 was used instead of the mica base paint 1.
[0087]
Comparative Example 1
A coating film for evaluation was prepared in the same manner as in Example 1 except that the mica base paint 4 was used instead of the mica base paint 1.
[0088]
[Evaluation]
(B value)
The b value of the highlight part and shade part of each coating film for evaluation was measured by X-Rite MA68II (multi-angle spectrocolorimeter manufactured by X-Rite). Observation condition D65 Measurement was performed at a measurement angle of 15 °, 25 °, 45 °, 75 °, and 110 ° with a 10 ° visual field. The results are shown in Table 1.
[0089]
(Visually)
The complementary color of the shade part of each evaluation coating film was visually evaluated according to the following criteria.
○: A complementary color in the shaded part with respect to the interference color of the highlight is not felt.
Δ: Slightly complementary color in shaded area with respect to highlight interference color.
X: A complementary color in the shade portion with respect to the interference color of the highlight is felt very strongly.
[0090]
[Table 1]

[0091]
From Table 1, it became clear that the complementary color (yellowishness) in the shade portion tends to decrease as the blending amount of microtitanium MT-500HD (fine particle titanium oxide) increases. Further, even when microtitanium MT-500HD was blended, the interference color in the highlight portion was hardly inhibited. It was revealed that the complementary color (yellowishness) in the shade part was suppressed in the visual evaluation even in the visual evaluation.
[0092]
【The invention's effect】
Since the multilayer coating film forming method of the present invention has the above-described configuration, the complementary color of the shade portion can be suppressed without impeding the design properties due to the interference color as much as possible. Therefore, it was suggested that the complementary color in the shade portion can be suppressed and a new paint color can be designed by suitably applying to automobiles and parts.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a cross-sectional view showing the structure of a multilayer coating film of the present invention.
[Explanation of symbols]
1 Clear coating
2 Mica base coating
3 Color base coating film
4 Intermediate coating film
5 Undercoat film
6 Base material (steel plate)

Claims (3)

A multi-layer coating film forming method in which a color base paint containing a color pigment, a mica base paint containing an interference mica pigment, and a clear paint are sequentially applied on a substrate on which an undercoat film and an intermediate coat film are formed,
The mica base paint state, and are not containing fine particles of titanium oxide an average particle diameter 0.01~0.1μm the coating comprising alumina and / or zirconia formed on the surface, the fine particles of titanium oxide is mica to interference mica pigment 100 parts by weight of the base paint, a multilayer coating film forming method characterized that you have been contained 0.1 to 10.0 parts by weight. A multilayer coating film formed by the multilayer coating film forming method according to claim 1 . An article comprising the multilayer coating film according to claim 2 .

Images