JP4676150B2 - High chroma metallic coating composition, coating film forming method, and coated article - Google Patents

Description

The present invention relates to a metallic coating composition, a coating film forming method, and a coated article that are red, highly saturated, and excellent in weather resistance.

Conventionally, high-saturation metallic paint colors, particularly red high-saturation metallic paint colors, have been difficult to achieve both of concealability, weather resistance, and painting workability. In general, an aluminum flake pigment is used to increase the hiding power. However, an uncolored aluminum flake pigment significantly reduces the saturation of the coating color, so that the amount of use is limited in order to obtain high saturation.

  As a technique for solving these problems, for example, Patent Document 1 discloses a color base containing a color base coating film, a colored aluminum pigment, and a mica pigment on a substrate on which an undercoat coating film and an intermediate coating film are formed. There is disclosed a technique for obtaining a red-colored mica coating having high saturation by sequentially forming a mica base coating and a clear coating having the same color as the coating. However, since the hiding power of the mica base coating film is low, a dedicated color base coating film having the same color as that of the mica base coating film is necessary, and thus there is a problem in that the coating process is limited. Furthermore, the colored aluminum pigment to be included in the color base coating film is a coating (wet) of a color pigment used for paint application on an aluminum flake pigment, and depending on the color pigment to be coated, the weather resistance is difficult, Long-term outdoor use may cause discoloration. In particular, organic red pigments are often inferior in weather resistance, and therefore have a problem that the hue is limited when weather resistance is taken into consideration.

  As a technique for solving the problem of weather resistance, Patent Document 2 discloses that a color base coating film, a colored aluminum pigment and a coating film containing an auxiliary coloring pigment of the same color, and a clear coating film are sequentially formed to have high saturation. In addition, it describes a laminated coating film that does not show any color jump even when used outdoors for a long period of time. Since this method also requires a dedicated color base coating film, it has a problem in the process as in the method described in Patent Document 1.

  As a technique for solving the problems in the process, Patent Document 3 describes a multilayer coating film including a coating film by a glittering coating composition containing colored vapor-deposited aluminum flakes and a vehicle. The use of very thin colored aluminum flakes produced by the vapor deposition method is advantageous in terms of concealment, and there is an advantage that a dedicated color base coating is not required. However, the method of coloring the deposited aluminum flakes is the same wet method as the above example, and has a problem in weather resistance. Also, very thin colored vapor deposited aluminum flakes are vulnerable to lateral forces, and may have poor mechanical stability in the coating composition.

JP 2001-321719 A

JP 2002-121488 A JP 2003-113348 A

Therefore, an object of the present invention is a metallic paint composition and coating material which can form a coating film excellent in concealability and weather resistance without providing a dedicated color base layer as a lower layer and having a red and highly saturated coating color. It is to provide a film forming method and a coated article.

The present invention
1. 1 to 20 parts by weight of iron oxide-coated aluminum flake pigment and 1 to 20 parts by weight of organic red pigment , and further iron oxide-coated alumina flake pigment and iron oxide coating, based on 100 parts by weight of resin solids in the coating composition A coating composition comprising one or more scale-like colored bright pigments selected from silica flake pigments, iron oxide-coated glass flake pigments and iron oxide-coated mica pigments, and metal flake pigments, and iron oxide-coated aluminum flake pigments However, the coating film containing only the iron oxide-coated aluminum flake pigment as a colorant has a hue angle h in the range of 0 to 50 ° in the L * C * h color system chromaticity diagram. The hue of the coating film obtained when the coating composition is applied is in the range of ± 25 ° within the hue angle h of the L * C * h color system chromaticity diagram centering on 0 °. , Saturation C * It is 0 or more, and the coating composition characterized in that black and white hiding film thickness is 18μm or less,
2. The coating composition according to 1, wherein the total content of the iron oxide-coated aluminum flake pigment, the scaly colored luster pigment, and the metal flake pigment is 10 to 20 parts by weight with respect to 100 parts by weight of the resin solid content in the coating composition. object,
3. A method for forming a coating film, wherein a clear coating material is further applied onto a coating film obtained by applying the coating composition according to item 1 or 2 to an object to be coated .
4). The present invention relates to a coated article obtained by the coating film forming method according to item 3 .

According to the present invention, it is possible to form a coating film that is red and highly saturated, and hardly shows any discoloration even when left outdoors for a long period of time.

First, the coating composition of the present invention will be described.

  The iron oxide-coated aluminum flake pigment used in the present invention is a scaly bright pigment, and the hue of the coating film containing only the iron oxide-coated aluminum flake pigment as a colorant is preferably L * C * h color system. In the chromaticity diagram, the hue angle h is preferably in the range of 0 to 50 °, and more preferably in the range of 20 to 40 °. The L * C * h color system here is a table devised based on the L * a * b * color system defined by the International Commission on Illumination in 1976 and adopted in JIS Z 8729. In the color system, h represents a hue angle, and is an angle moved counterclockwise with the red axis as 0 ° in the chromaticity diagram. Hue angle h is measured by Konica Minolta CR series (trade name), a color difference meter, SN color computer (trade name) by Suga Test Instruments Co., Ltd., and X-Lite, a multi-angle spectrophotometer. MA-68 (trade name) or the like can be used. The iron oxide-coated aluminum flake pigment is not particularly limited. For example, the iron oxide is formed on the aluminum base by a chemical vapor deposition method as described in JP-A-6-145555 and the like. Examples thereof include colored aluminum flake pigments excellent in weather resistance. The content of the iron oxide-coated aluminum flake pigment in the coating composition is within the range of 1 to 20 parts by weight with respect to 100 parts by weight of the resin solid content in the coating composition from the viewpoint of the finish of the coating film. Is preferable, and it is especially preferable to be within the range of 3 to 15 parts by weight.

  As the organic red pigment used in the coating composition of the present invention, conventionally known pigments for coatings and inks can be used singly or in combination of two or more depending on the desired color. Specific examples of the organic red pigment include azo pigments, quinacridone pigments, diketopyrrolopyrrole pigments, perylene pigments, and perinone pigments. The content of the organic red pigment is preferably in the range of 1 to 20 parts by weight, more preferably 5 to 15 parts by weight with respect to 100 parts by weight of the resin solid content in the coating composition from the viewpoint of the saturation of the coating film. Within range.

  The coating composition of the present invention may further include one or more scaly colorings selected from iron oxide-coated alumina flake pigment, iron oxide-coated silica flake pigment, iron oxide-coated glass flake pigment, and iron oxide-coated mica pigment as necessary. Bright pigments can be included. Among them, it is particularly preferable to contain an iron oxide-coated mica pigment. These contents are preferably 15 parts by weight or less, more preferably in the range of 1 to 10 parts by weight with respect to 100 parts by weight of the resin solid content in the coating composition from the point of saturation of the coating film.

  The coating composition of the present invention can further contain a metal flake pigment for the purpose of increasing the hiding power without lowering the saturation. As the metal flake pigment, any one of conventionally known ones for paints can be used in combination of one or more. Examples of the metal used as a raw material include aluminum, copper, nickel alloy, and stainless steel. The content in the coating composition is preferably 15 parts by weight or less, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the resin solid content in the coating composition from the viewpoint of the concealability and finish of the coating film. Is within the range.

  The total content of the iron oxide-coated aluminum flake pigment, scaly colored bright pigment and metal flake pigment used in the coating composition of the present invention is 100 parts by weight of the resin solid content in the coating composition. From the viewpoint of finish, saturation and concealment, it is preferably in the range of 10 to 20 parts by weight, more preferably 12 to 18 parts by weight.

  The coating composition of the present invention can usually contain a resin component as a vehicle. Specific examples of the resin component include base resins such as acrylic resins, polyester resins, alkyd resins, and urethane resins having a crosslinkable functional group such as a hydroxyl group, melamine resins, urea resins, polyisocyanate compounds (block bodies). Are used in combination with a crosslinking agent such as an organic solvent and / or a solvent such as water.

  Furthermore, various additives such as a solvent such as water or an organic solvent, a pigment dispersant, an antisettling agent, a curing catalyst, an antifoaming agent, an antioxidant, and an ultraviolet absorber are added to the coating composition of the present invention as necessary. An agent, extender, etc. can be appropriately blended.

  The coating composition of the present invention is prepared by mixing and dispersing the aforementioned components. The solid content at the time of painting is adjusted to 12 to 50% by weight, preferably 15 to 30% by weight based on the coating composition, and the viscosity at 20 ° C. is adjusted to 15 to 20 seconds / ford cup # 3. It is preferable to keep it.

  The coating composition of the present invention can be applied by a method such as electrostatic coating, air spray, airless spray, etc., and its film thickness should be in the range of 10 to 45 μm based on the cured coating film. From the viewpoint of the smoothness of the coating film. The coating composition itself of the coating composition of the present invention can usually be crosslinked and cured at a temperature of about 70 to about 150 ° C.

  In the coating composition of the present invention, the hue of the coating film obtained when applied is in the range where the hue angle h of the L * C * h color system chromaticity diagram is ± 25 ° or less centering on 0 °. C * is 50 or more. Specifically, the saturation C * is obtained by applying a coating composition on a coating plate on which a gray (N-7) coating film has been formed in advance and curing the coating composition, MA-68 manufactured by X-Lite. (Product name) can be used for measurement.

  The coating composition of the present invention is characterized in that the black-and-white concealment film thickness is 18 μm or less. The black-and-white concealment film thickness means a minimum film thickness that makes it impossible to visually distinguish white portions and black portions that are printed on a concealment rate test paper (manufactured by Nippon Test Panel Co., Ltd.) and then dried and cured.

  The method of the present invention relates to a coating method for coating a substrate with the coating composition as described above. Examples of the base material include metals such as iron, zinc, and aluminum, alloys containing these, molded products plated or vapor-deposited with these metals, molded products made of glass, plastics, foams, and the like. be able to. Depending on these materials, it can be appropriately degreased or surface treated to form a substrate. Furthermore, an undercoat film or an intermediate coat film can be formed on the substrate to form a substrate, and these are particularly preferable.

  The undercoat film is formed to conceal the surface of the material or impart anticorrosion and rustproofness to the material, and can be obtained by applying an undercoat paint, drying and curing. it can. The type of the undercoat paint is not particularly limited, and examples thereof include an electrodeposition paint and a solvent-type primer.

  The intermediate coating film is formed to conceal the surface of the material or the undercoating film, or to impart adhesion or chipping resistance. It can be obtained by applying a paint and drying and curing. The type of intermediate coating is not particularly limited, and known ones can be used. For example, an organic solvent-based or water-based intermediate coating containing a thermosetting resin composition and a color pigment as essential components can be preferably used. .

  In the case where an undercoat film or an intermediate coat film is formed as the substrate, the undercoat film or the intermediate coat film can be heated, and a coating material for the next step described later can be applied after crosslinking and curing. Or the coating material of the next process can also be applied in a state where the undercoat film and / or the intermediate coat film are uncured.

  In the present invention, a top clear coating film can be formed by further coating one or more top clear coatings on the coating film obtained by coating the coating composition as described above. The top clear paint is a paint that is applied to the uncured or cured surface of the above-mentioned paint composition. The top clear paint is mainly composed of a resin component and a solvent, and may contain other paint additives as required. A liquid paint that forms a colorless or colored transparent coating film.

  As the top clear coating in the method of the present invention, conventionally known ones can be used without limitation. For example, a liquid or powdery coating composition containing a base resin and a crosslinking agent can be applied. Examples of the base resin include acrylic resin, polyester resin, alkyd resin, fluororesin, urethane resin, and silicon-containing resin containing a crosslinkable functional group such as a hydroxyl group, a carboxyl group, a silanol group, and an epoxy group. It is done. As a crosslinking agent, a melamine resin capable of reacting with the functional group of the base resin, urea resin, polyisocyanate compound, block polyisocyanate compound, epoxy compound or resin, carboxyl group-containing compound or resin, acid anhydride, Examples thereof include alkoxysilane group-containing compounds or resins. Further, if necessary, additives such as a solvent such as water and an organic solvent, a curing catalyst, an antifoaming agent, an ultraviolet absorber, a rheology control agent, an antioxidant, and a surface conditioner can be appropriately blended.

  In the top clear coating in the method of the present invention, a color pigment can be blended in a timely manner within a range not impairing transparency. As the color pigment, one or a combination of two or more conventionally known pigments for ink and paint can be blended. The amount of addition may be appropriately determined, but is 30 parts by weight or less, preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the resin solid content in the clear coating film.

  The top clear coating in the present invention can be applied by a method such as electrostatic coating, air spray, airless spray, etc., and its film thickness should be in the range of 15 to 70 μm based on the cured coating film. preferable. The coating film of the top clear coating itself can be crosslinked and cured usually at a temperature of about 70 to 150 ° C.

  The coating film forming method of the present invention is a so-called 2C2B process in which the coating composition as described above is applied, heated and dried and cured, and then the top clear coating is applied on the coated film and heated and dried and cured. However, a multi-layer coating film can also be obtained by the so-called 2C1B process in which the top clear paint is applied in an uncured state after the coating composition is applied, and then heated to cure them simultaneously. .

  The coated article of the present invention can be obtained by the coating film forming method.

Next, an Example is given and this invention is demonstrated more concretely.

Examples 1 to 4 and Comparative Examples 1 and 2
Preparation of base material Degreased and zinc phosphate-treated steel plate (JISG3141, size 400 × 300 × 0.8 mm), cationic electrodeposition paint “Electron 9400HB” (trade name: manufactured by Kansai Paint Co., Ltd., epoxy resin polyamine-based cationic resin (Using a block polyisocyanate compound as a curing agent) is electrodeposited so as to have a film thickness of 20 μm based on the cured coating film, and heated at 170 ° C. for 20 minutes to be crosslinked and cured to be electrodeposited. A membrane was obtained.

On the obtained electrodeposition coating surface, an intermediate coating “Lugabek intermediate coating gray” (trade name: manufactured by Kansai Paint Co., Ltd., polyester resin / melamine resin type, organic solvent type) is applied by air spray. Based on the film, it was coated to a film thickness of 30 μm, heated at 140 ° C. for 30 minutes to be crosslinked and cured, and a coated plate on which an intermediate coating film was formed was used as a base material.
Preparation of coating material Stirring and mixing with a ratio of the luster and coloring pigment shown in Table 1 per 100 parts by weight (solid content) of a resin component comprising a hydroxyl group-containing acrylic resin (hydroxyl value 100, number average molecular weight 20000) and melamine resin The organic solvent type paint having a solid content of about 25% was prepared by diluting to a viscosity suitable for coating, and a coating composition used for each example and comparative example was prepared.

Color measurement The coating composition prepared in (2) was applied to the base material prepared in (1) by air spraying to a thickness of 30 μm based on the cured coating film, and heated at 140 ° C. for 30 minutes for crosslinking and curing. The coated plate thus formed was measured with a multi-angle spectrophotometer (MA-68, trade name, manufactured by X-Lite), and the hue angle h and saturation C * in the L * C * h color system were determined. Obtained. The light receiving angle was 15 ° corresponding to the highlight. The results are shown in Table 2.

Measurement of concealment film thickness The coating compositions prepared in (2) were each sprayed on concealment rate test paper (manufactured by Nippon Test Panel Co., Ltd.) based on the cured coating film, 15, 16, 17, 18, 20, The coating film formed by coating so as to have a film thickness of 6 steps of 50 μm and heating at 140 ° C. for 30 minutes to be cured by cross-linking was visually observed outside in direct sunlight during the day. When the white part and the black part printed on the test paper could not be discriminated when observed from above the coating film, it was judged as the concealment film thickness. The results are shown in Table 2.
Evaluation of weather resistance The coating composition prepared in (2) was applied to the base material prepared in (1) using a REA gun, respectively, at 25 ° C. and 75% humidity as a cured coating film. Then, leave it at room temperature for 15 minutes, and then apply a clear paint (Lugabe Clear, manufactured by Kansai Paint, trade name, acrylic resin / amino resin, organic solvent) to these uncured surfaces. The mold was coated as a cured coating film using a mini-bell rotary electrostatic coating machine under conditions of a boot temperature of 25 ° C. and a humidity of 75% so as to be 25 to 35 μm. After coating, leave at room temperature for 15 minutes, then use a hot-air circulating drying oven and heat at 140 ° C. for 30 minutes to dry and cure the multilayer coating at the same time as a test plate for accelerated weathering test Provided.

  For the accelerated weather resistance test, a super xenon weatherometer specified by JIS B 7754 (trade name, manufactured by Suga Test Instruments Co., Ltd.) was used, and irradiation was carried out for 1 hour 42 minutes with xenon arc lamp and 18 minutes of rain. Evaluation was performed in comparison with a pre-coated plate stored in the laboratory after the end of the 500 cycle repetition test, with 2 hours of irradiation with the lamp as one cycle. The results are shown in Table 2.

The coating film forming method of the present invention can be applied to various industrial products, particularly to the outer plate of an automobile body.

Claims (4)

The iron oxide-coated aluminum flake pigment is 1 to 100 parts by weight of the resin solid content in the coating composition.
20 parts by weight and 1 to 20 parts by weight of organic red pigment, and one or more scales selected from iron oxide-coated alumina flake pigment, iron oxide-coated silica flake pigment, iron oxide-coated glass flake pigment, and iron oxide-coated mica pigment The coating film composition comprising a colored pigment and a metal flake pigment, wherein the iron oxide-coated aluminum flake pigment contains only the iron oxide-coated aluminum flake pigment as a colorant has a hue of L * C * h In the color system chromaticity diagram, a coating composition having a hue angle h in the range of 0 to 50 °, and the hue of the coating film obtained when the coating composition is applied is L * When the hue angle h of the C * h color system chromaticity diagram is within ± 25 ° centering on 0 °, the saturation C * is 50 or more and the black and white masking film thickness is 18 μm or less. A coating composition. Total content of iron oxide-coated aluminum flake pigment, scaly colored luster pigment and metal flake pigment
The coating composition according to claim 1, wherein is 10 to 20 parts by weight with respect to 100 parts by weight of the resin solid content in the coating composition. A method of forming a coating film, wherein a clear coating material is further applied on a coating film obtained by applying the coating composition according to claim 1 or 2 to an object to be coated . The coated article obtained by the coating-film formation method of Claim 3 .