JP2006263568A - Method for forming golden coating film and golden coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golden coating film having a silky feeling, and a formation method of a golden coating film for forming the golden coating film. <P>SOLUTION: The method for forming the golden coating film has a base coating film formation step in which an intermediate coating film 10 is coated with a base coating containing a scale-like titanic acid pigment to form a base coating film 12; a baking step for baking and curing the base coating film 12; a clear coating film formation step for forming a clear coating film 14 on the base coating film 12; a baking step for baking the clear coating film; a yellowing step for coating the clear coating film 14 with hydrogen peroxide to yellow the titanic acid pigment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for forming a golden paint film and a golden paint film, and more particularly to a method for forming a golden paint film capable of expressing a golden color having a silky feeling and a golden paint film.

  Conventionally, for example, as yellow coatings for vehicles and home appliances, Patent Document 1 and Patent Document 2 disclose that a yellow transparent viscous liquid is obtained by adding hydrogen peroxide to titanium hydroxide gel in the presence of titanium oxide sol. It has been proposed to use a yellow-coated aluminum pigment obtained by coating the surface of an aluminum pigment with this yellow transparent viscous liquid. Further, a method has been proposed in which a solvent-based paint having this yellow-coated aluminum pigment is applied on an intermediate coating film, a clear paint is applied on an uncured coating surface, and then both coating films are cured simultaneously.

  However, since the thickness of the aluminum pigment itself is usually 200 to 500 nm, when the surface of the aluminum pigment is coated with a yellow transparent viscous liquid, a yellow-coated aluminum pigment having a thickness of at least the above thickness is obtained. On the other hand, since the base coating film is usually formed with a thickness of 10 to 20 μm, even if the yellow coating aluminum pigment can be well oriented on the base coating film, dozens of layers of yellow coating aluminum are used. The pigment was not oriented, and therefore a golden coating film having a silky feeling could not be obtained even with a yellow coating film. In addition, when an uncured clear coating is applied on a base coating containing a yellow coating aluminum pigment and this base coating and the clear coating are cured simultaneously, the yellow coating aluminum pigment in the base coating is usually As a result, it was extremely difficult to obtain a golden coating film having a silky feeling without being highly oriented.

  Moreover, as shown in FIG. 11, it is also conceivable to obtain a yellow paint by mixing a yellow organic or inorganic pigment with an ultrathin scaly titanate pigment.

JP 2004-189801 A JP 2004-189803 A

  However, as shown in FIG. 11, the orientation of the titanate pigment is inhibited by the yellow organic or inorganic pigment in the yellow paint, resulting in a yellow paint film, but still having a silky feeling. It was impossible to form.

  This invention is made | formed in view of the said subject, and provides the formation method of the golden color coating film which forms the golden color coating film which has a silky feeling, and the golden color coating film.

  The method for forming a golden coating film of the present invention has the following characteristics.

  (1) A base coating film forming step of forming a base coating film by applying a base coating containing a scale-like titanate pigment on an intermediate coating film or a colored base coating film, and clear coating on the base coating film A method for forming a golden coating film, comprising: a clear coating film forming process for forming a film; and a yellowing process for applying a hydrogen peroxide on the uppermost coating film to yellow the titanate pigment.

  The scaly titanate pigments are present in a highly aligned and densely arranged state in the base coating film. On the other hand, when the hydrogen peroxide is applied to the uppermost coating film and this hydrogen peroxide penetrates into the lower layer and causes a chemical reaction with the titanate pigment in the base coating film, the titanate pigment turns yellow. As a result, in the base coating film, a golden coating film having a silky feeling in which ultrathin scaly yellow pigments are densely and highly oriented is formed.

  (2) The method for forming a golden coating film according to (1) above includes a preheating process for volume shrinking at least the base coating film between the clear coating film forming process and the yellowing process.

  Before the clear coating film is formed on the base coating film, baking is performed to cure the base coating film, whereby the titanic acid pigment in the base coating film is more densely oriented and fixed. After that, by forming a clear coating and applying hydrogen peroxide from the top coating, the hydrogen peroxide that permeates the lower layer reacts with the denser and highly oriented titanate pigment, resulting in a silky golden color A coating film can be formed.

  (3) In the method for forming a golden coating film according to (1) or (2), the intermediate coating film is a white base coating film or a colored base coating film having a titanium white pigment.

  By making the intermediate coating film into a white intermediate coating film, the reflectivity of the yellowed titanate pigment in the base coating film is further improved, and the golden color becomes more conspicuous. Further, it is a colored base coating film containing a titanium white pigment or aluminum flakes, which improves the reflectivity of the yellowed titanate pigment in the golden base coating film 16 and improves the golden color. Will stand out more.

  (4) In the method for forming a golden coating film according to any one of (1) to (3), the uppermost coating film is the clear coating film.

  The distance between crosslinks in the clear coating is very large compared to hydrogen peroxide molecules. Therefore, by applying hydrogen peroxide on the clear coating film, hydrogen peroxide easily penetrates into the lower base coating film, and the titanate pigment in the base coating film can be yellowed.

(5) In the method for forming a golden coating film according to any one of (1) to (4), the titanate pigment is TiO _x (X> 2).

  The titanic acid pigment can be obtained by treating the layered titanate with an acid and then allowing the organic basic compound to act to form flaky titanic acid with the layers peeled off to obtain an ultrathin scaly pigment.

  The golden paint film of the present invention has the following characteristics.

  A golden-colored coating film formed by the method for forming a golden-colored coating film according to any one of (1) to (5) above.

  A golden-colored coating film comprising at least one coating film in a state in which yellow scaly pigments obtained by yellowing a titanic acid pigment by hydrogen peroxide treatment are highly oriented and densely arranged.

  Since the yellowish yellow scaly pigment is densely and highly oriented, irregular reflection is suppressed and a golden-colored coating film with a higher silky feeling is obtained.

  ADVANTAGE OF THE INVENTION According to this invention, irregular reflection can be suppressed and the golden-colored coating film with a higher silky feeling can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Golden color film formation method]
As shown in FIGS. 1 and 2, the method for forming a golden coating film according to a preferred embodiment of the present invention is based on the intermediate coating film 10 shown in FIG. A base coating film forming step for forming the base coating film 12 by coating on the colored base coating film 11 shown in FIG. 2, a clear coating film forming step for forming the clear coating film 14 on the base coating film 12, Applying a hydrogen peroxide on the coating film (that is, performing a hydrogen peroxide treatment) to yellow the titanate pigment. Since the scale-like titanate pigment is an extremely thin scale-like pigment as described later, it exists in a highly aligned and densely arranged state in the base coating film. On the other hand, when the hydrogen peroxide is applied to the uppermost coating film and this hydrogen peroxide penetrates into the lower layer and causes a chemical reaction with the titanate pigment in the base coating film 12, the titanate pigment turns yellow. As a result, the base coating film 12 becomes a golden base coating film 16 having a silky feeling in which ultrathin scaly yellow pigments are densely and highly oriented, and the entire laminated coating film becomes a golden coating film.

  Moreover, it has the preheating process which carries out volume shrinkage of the said base coating film 12 between the said clear coating-film formation process and the yellowing process. Before the clear coating film 14 is formed on the base coating film 12, the titanic acid pigment in the base coating film 12 can be more precisely oriented and fixed by baking and curing the base coating film 12. . Thereafter, a clear coating film 14 is formed, and hydrogen peroxide is applied from the uppermost coating film, so that the hydrogen peroxide that has penetrated into the lower layer reacts with the titanic acid pigment that is denser and highly oriented, and has a higher silky feeling. A color coating can be formed. In the present embodiment, it is desirable to further form a clear coating film on the base coating film 12 and perform baking, that is, in the intermediate coating film 10, the base coating film 12, and the clear coating film 14, three coats one preheat 2 Bake is desirable.

  More preferably, the intermediate coating film 10 shown in FIG. 1 is a white intermediate coating film. By making the intermediate coating film 10 into a white intermediate coating film, the reflectivity of the yellowed titanate pigment in the golden base coating film 16 is improved, and the golden color becomes more conspicuous. Further, the colored base coating film 11 shown in FIG. 2 is a colored base coating film containing titanium white pigment or aluminum flakes, and as a result, the yellowed titanate pigment in the golden base coating film 16 is more like the above. The reflectivity is improved and the golden color becomes more prominent.

  Further, the uppermost coating film is a clear coating film 14. The distance between crosslinks of the clear coating film 14 is larger than that of hydrogen peroxide molecules. Therefore, by applying hydrogen peroxide on the clear coating film 14, the hydrogen peroxide easily penetrates into the lower base coating film 12, and the titanate pigment in the base coating film 12 can be yellowed.

  Examples of the method for applying hydrogen peroxide include a method in which a hydrogen peroxide solution is prepared and this hydrogen peroxide solution is applied by, for example, an airless spray, an air spray, a roll coater, a curtain flow coater, or the like. Moreover, you may immerse the uppermost coating film of the laminated | stacked coating film in hydrogen peroxide solution. In any case, it is desirable that after the application of hydrogen peroxide, the laminated coating film is allowed to stand and the hydrogen peroxide is immersed in the lower layer, that is, the base layer.

  As the hydrogen peroxide solution, it is desirable to use a hydrogen peroxide solution having a high concentration of 25 to 35% by weight. By using a high-concentration hydrogen peroxide solution, the total amount of hydrogen peroxide solution for yellowing the titanate pigment can be reduced, and the subsequent drying step can be shortened.

The treatment amount of hydrogen peroxide is 0.01 to 1 mL / cm ² with respect to the surface area of the uppermost coating film, for example, a clear coating film, with 30% by weight of hydrogen peroxide water, preferably 0.03 to 0. 0.07 mL / cm ² . Above 1 mL / cm ² , the yellowing of the titanate pigment does not improve, while below 0.01 mL / cm ² , yellowing to obtain the desired golden color, ie L ^* a ^* b ^*. The b ^* value in the color system cannot obtain 16 or more. In this Embodiment, it is preferable that b ^* value in the laminated coating film formed even to the clear coating film is 16-20. By setting it as this range, a vivid yellow feeling and a golden feeling can be obtained.

  The base paint for forming the base coating film 12 includes a solvent-based base paint and an aqueous base paint. An aqueous base paint, particularly a thermosetting aqueous paint, contains a scaly titanate pigment, a resin that can be dissolved or dispersed in water, a cross-linking agent as necessary, and water as a solvent. As a resin that can be dissolved or dispersed in water, for example, a resin containing a hydrophilic group such as a carboxyl group and a crosslinkable functional group such as a hydroxyl group in one molecule, specifically, an acrylic resin, a polyester resin, A polyurethane resin etc. are mentioned. Examples of the crosslinking agent include hydrophobic or hydrophilic alkyl ether melamine resins and blocked isocyanate compounds. On the other hand, the solvent-based base paint contains a scaly titanate pigment, a resin similar to the above, and a cross-linking agent and a solvent as necessary. In addition, when baking and curing the base coating film before forming the clear coating film, it is not necessary to consider the affinity of the hydrogen peroxide solution, so either water-based paint or solvent-based paint is used for base coating formation. Also good.

  The base coating film 12 is applied with a film thickness of 10 to 15 μm when a water-based base paint is used, and is applied with a film thickness of 12 to 18 μm when a solvent-based base paint is used.

  In the present embodiment, the clear paint forming the clear paint film 14 is preferably a thermosetting paint capable of forming a colorless and transparent paint film, such as a thermosetting resin, an organic solvent, and an ultraviolet absorber if necessary. Is contained. Examples of the thermosetting resin include resins such as an acrylic resin, a polyester resin, an alkyd resin, a fluororesin, a urethane resin, and a silicon-containing resin having a crosslinkable functional group such as a hydroxyl group, a carboxyl group, a silanol group, and an epoxy group. Melamine resin, urea resin, (block) polyisocyanate compound, epoxy resin compound or resin, carboxyl group-containing compound or resin, acid anhydride, alkoxysilane group-containing compound or resin, etc. that can react with these crosslinkable functional groups It consists of a crosslinking agent.

  Moreover, the clear coating film 14 is painted by the film thickness of 30-40 micrometers.

As the titanic acid pigment described above, TiO _x (x> 2), for example, by treating a layered titanate with an acid and then allowing an organic basic compound to act to form a flaky titanic acid separated from the layer, An ultrathin scaly pigment can be obtained.

  Below, an example of the manufacturing method of an ultra-thin scaly titanic acid pigment is demonstrated using FIG.

The layered titanate K _0.8 Li _0.27 Ti _1.73 O ₄ is treated with acid, and the exchangeable metal cation is replaced with hydrogen ion or hydronium ion to form layered titanate (for example, H _1.07 Ti _1.73 O ₄ .nH ₂ O ) Is obtained. An organic basic compound is allowed to act on the layered titanic acid and the layers are separated to obtain an aqueous medium dispersion (peeling sol) of flaky titanic acid. As the organic basic compound, dimethylethanolamine (DMEA) is desirable.

  Preferably, cesium carbonate is then added to the stripping sol to replace the organic basic compound with cesium ions, excess cesium carbonate and generated amine carbonate are removed by centrifugal washing, and further, titanic acid is obtained by bubbling carbon dioxide gas. To form a neutralized sol. The resulting flaky titanic acid aqueous medium dispersion (release sol) has improved light resistance.

  As shown in FIG. 4, titanic acid of the obtained neutralized sol is obtained as scaly titanic acid in which about 1 nm of titanic acid is laminated and 2 to 50 layers of titanic acid are laminated. The scaly titanic acid has a thickness of 50 nm or less, preferably 10 to 50 nm at the maximum, and has a scaly longitudinal length (particle size) of 15 to 20 μm. This scale-like titanic acid pigment is arranged in a highly oriented and dense manner in the base coating film as shown in the scanning electron micrograph of the cross section of the base coating film shown in FIG. 7 by using the coating film forming method described above. .

<Synthesis of flaky titanic acid dispersion>
(Synthesis Example 1)
A raw material in which 67.01 g of titanium oxide, 26.78 g of potassium carbonate, 12.04 g of potassium chloride and 5.08 g of lithium hydroxide were pulverized and mixed in a dry process was calcined at 1020 ° C. for 4 hours. 7.9 kg of 10.9% aqueous slurry of the obtained powder was prepared, 470 g of 10% aqueous sulfuric acid solution was added and stirred for 2 hours, and the pH of the slurry was adjusted to 7.0. What was separated and washed with water was dried at 110 ° C. and then calcined at 600 ° C. for 12 hours. The obtained white powder was layered titanate K _0.6 Li _0.27 Ti _1.73 O _3.9 and had an average major axis of 15 μm.

65 g of this layered titanate was dispersed and stirred in 5 kg of 3.5% hydrochloric acid, reacted at 40 ° C. for 2 hours, separated by suction filtration, and washed with water. The obtained layered titanic acid had a K ₂ O remaining amount of 2.0% and a metal ion exchange rate of 94%.

  While dispersing and stirring the total amount of layered titanic acid obtained in 1.6 kg of deionized water, a solution prepared by dissolving 34.5 g of dimethylethanolamine in 0.4 kg of deionized water was added and stirred at 40 ° C. for 12 hours. Thus, a flaky titanic acid dispersion having a pH of 9.9 was obtained. The concentration was adjusted to 5.0% by weight by centrifugation at 10,000 rpm for 10 minutes. The obtained flaky titanic acid dispersion did not show solid sedimentation even after standing for a long time, and the solid content obtained by drying it at 110 ° C. for 12 hours showed a weight loss of 200 ° C. or more by TG / DTA analysis. Was 14.7% by weight, and the interlayer distance was 10.3 mm by XRD analysis.

(Synthesis Example 2)
200 g of the flaky titanic acid dispersion of Synthesis Example 1 was prepared with deionized water to a concentration of 1.7 wt%, 120 g of a 5 wt% aqueous cesium carbonate solution was added while stirring, and the mixture was stirred at room temperature for 1 hour, Intercalation ions of titanic acid were replaced with cesium ions from dimethylethanolammonium. After centrifuging at 10,000 rpm for 10 minutes, the supernatant was collected, and the operation of re-diluting the sedimented concentrated flaky titanic acid dispersion with deionized water was repeated three times to remove excess cesium carbonate and desorbed dimethylethanolamine together with the supernatant. Removed. Thereafter, the pH was adjusted to 7.9 by bubbling carbon dioxide, and the concentration was adjusted to 5.0% by weight by re-centrifuging. The obtained flaky titanic acid dispersion was allowed to stand for a long time, and no solid content was observed. The solid content dried at 110 ° C. for 12 hours had a weight loss of 200 ° C. or more by TG / DTA analysis. It was 8% by weight, the interlayer distance was 9.3 mm by XRD analysis, and the Cs ₂ O content was 20.2% by fluorescent X-ray analysis.

  In the present embodiment, as the scaly titanate pigment, one having a thickness of 50 nm and a length (particle diameter) in the longitudinal direction of 15 μm as shown in FIG. 5 is mainly used. The aspect ratio of the scaly titanate pigment (ratio of thickness to length in the longitudinal direction) is 250 to 400. On the other hand, a conventionally used metallic pigment having a titanium oxide film coated on an alumina surface has a thickness of 400 to 500 nm and a longitudinal length (particle size) of about 20 μm, as shown in FIG. The aspect ratio is 40-50. FIG. 8 shows the cross section of the above aluminum coating film when a metallic pigment coated with titanium oxide on the surface is used as a base paint. Lack.

  As described above, the flaky titanate pigment used in the present embodiment has an ultra-high aspect ratio compared to the conventional titanium oxide-coated alumina pigment, and as a result, the ultrathin flaky titanate of the present embodiment. The pigment is densely arranged in a highly oriented manner in the base coating film, and there is no glare feeling like the conventional titanium oxide-coated alumina pigment, and a golden coating film with a high silky feeling can be obtained.

  The scaly titanic acid pigment is contained in the above-mentioned base paint at a content rate of PWC (pigment wright content: solid content to paint resin) of 15 to 30%.

[Golden paint film]
The golden coating film of the present embodiment is a golden coating film formed by the above-described golden coating film forming method, and the titanate pigment was yellowed by hydrogen peroxide treatment as shown in FIG. This is a golden coating film having a golden base coating film 16 in which yellow scale pigments are highly oriented and densely arranged.

  Since the yellowed ultra-thin scaly titanate pigment is densely and highly oriented in the base coating film, irregular reflection is suppressed and the golden coating film has a higher silky feeling.

  Below, the formation method of the golden-colored coating film of this invention is demonstrated using an Example.

  In this example, the following paints were used. That is, a paint having a polyester resin and a melamine resin as the base resin was used as the intermediate coating. Further, as a base paint, acrylic resin and melamine resin are used as equipment resins, and the above-described scaly titanate pigment having a thickness of 50 nm and a length (particle diameter) in the longitudinal direction of 15 μm is contained at a content rate of PWC 20%. Paint was used. Further, as the clear paint, a paint containing a base resin composed of a two-component urethane resin of acrylic resin, melamine resin, acid acrylic resin / epoxy acrylic resin was used.

FIG. 9 shows a method for forming a coating film of this example. First, a white intermediate coating was applied to an electrodeposited steel sheet so as to have a film thickness of 35 μm, and baked at a maximum attained temperature of 140 ° C. for 18 minutes. Next, the scaly titanate pigment-containing base paint was applied with a film thickness of 13 μm when the base paint was an aqueous base paint, and was applied with a film thickness of 15 μm when the base paint was a solvent-based base paint. Here, when a water-based base paint was used, baking was performed for 10 minutes at a maximum temperature of 80 ° C., and when a solvent-based base paint was used, a flash time was provided for 1 minute. Here, the flash time refers to the time from applying the base paint to applying the clear paint. Thereafter, a clear paint was applied on the base coating film so as to have a film thickness of 35 μm, and baked by holding at a maximum reached temperature of 140 ° C. for 18 minutes. Next, 30% by weight of hydrogen peroxide water was sprayed onto the clear coating film by air spray so that the surface area of the clear coating film was 0.05 mL / cm ² . The treatment time was 20 minutes or longer.

FIG. 10 shows the result of b ^* value measurement at an incident angle of 45 ° and a light receiving angle of 45 ° using a multi-angle colorimeter “X-Rite MA68II” (manufactured by X-Rite). As shown in FIG. 10, the b ^* value increased from 6 to 19 and later became 17 as hydrogen peroxide penetrated to yellow the ultrathin scaly titanate pigment in the base coating film. Here, a b ^* value of 17 is a very bright yellow color, and furthermore, since the ultrathin scaly titanate pigments are densely arranged in a high orientation, the silky feeling is also high, and therefore the golden color with a high silky feeling. A coating film could be obtained.

  In addition, the number of pigments in the coating film that can be oriented is calculated according to the coating method and conditions, and is shown in the following table. The cross section of the base coating film using each pigment was observed with a scanning electron microscope, and the number of pigments per 10 μm in the thickness direction of each base coating film cross section was calculated. The base paint using a conventional titanium oxide-coated alumina pigment was formed under the same conditions as the base coating except that the pigment was a titanate pigment and a titanium oxide-coated alumina pigment.

  In order to express a silky feeling, at least 50 pieces / 10 μm or more must be oriented. As shown in Table 1, it is clear that the titanium oxide-coated alumina pigment shown in FIG. 8 cannot obtain a sufficient silky feeling, and the golden color having a silky feeling is not used for the first time by using the yellowed titanate pigment of the present invention. It can be seen that the design can be expressed.

  The method for forming a golden color coating film and the golden color coating film of the present invention are effective for any application as long as the application requires a golden coating having a silky feeling. It can use for formation of a frequent-use coating film.

It is a figure explaining the one aspect | mode of the formation method of the golden color coating film of this invention. It is a figure explaining the other aspect of the formation method of the golden-colored coating film of this invention. It is a figure explaining an example of the manufacturing method of the titanate pigment with which it uses for the formation method of the golden color coating film of this invention. It is a figure explaining the orientation degree in the titanic acid pigment used for the golden color coating film of this invention, and its base coating film. It is a figure explaining an example of the titanate pigment used for the formation method of the golden-colored coating film of this invention. It is a figure explaining an example of the conventional titanium oxide coat alumina pigment. It is the scanning electron micrograph which image | photographed the cross section of the titanate pigment containing base coating film formed using the formation method of the golden coating film of this invention. It is the scanning electron micrograph which image | photographed the cross section of the base coating film containing the conventional titanium oxide coating alumina pigment. It is a figure explaining the process of the formation method of the golden coating film of a present Example. It is a graph which shows the relationship between the elapsed time after hydrogen peroxide application | coating in a present Example, and b ^* value of a golden-colored coating film. It is a figure explaining the state of the base coating film containing a yellow pigment and a titanate pigment.

Explanation of symbols

  10 intermediate coating film, 12 base coating film, 14 clear coating film, 16 golden base coating film.

Claims (7)

A base coating film forming step of forming a base coating film by applying a base coating containing a scaly titanate pigment on an intermediate coating film or a colored base coating film;
A clear coating film forming step for forming a clear coating film on the base coating film;
A yellowing step of applying hydrogen peroxide on the uppermost coating and yellowing the titanate pigment;
A method for forming a golden coating film, comprising: In the formation method of the golden-colored coating film of Claim 1,
A method for forming a golden-colored coating film, comprising a preheating process for volume shrinking at least the base coating film between the clear coating film forming process and the yellowing process. In the formation method of the golden-colored coating film of Claim 1 or Claim 2,
The method for forming a golden coating film, wherein the intermediate coating film is a white base coating film or a colored base coating film having a titanium white pigment. In the formation method of the golden-colored coating film of any one of Claims 1-3,
The method for forming a golden paint film, wherein the top paint film is the clear paint film. In the formation method of the golden-colored coating film of any one of Claims 1-4,
The method for forming a golden paint film, wherein the titanate pigment is TiO _x (X> 2).   A golden paint film formed by the method for forming a golden paint film according to any one of claims 1 to 5. A golden-colored coating film comprising at least one coating film in a state in which yellow scaly pigments obtained by yellowing a titanic acid pigment by hydrogen peroxide treatment are highly oriented and densely arranged.

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