JP5588269B2 - Powder coating aluminum building materials for outdoor use - Google Patents

Description

  The present invention relates to a powder-coated aluminum building material for outdoor use such as an aluminum sash, an aluminum curtain wall, an aluminum stand, and an aluminum gate.

  As this kind of electrostatic coating method (which may be called electrostatic powder coating method), for example, it is excellent in weather resistance by electrostatic coating using a hot blend powder coating obtained by heating and kneading polyester coating and fluorine coating. An aluminum building material such as an aluminum sash having a functional coating film is known.

  According to Patent Document 1, a hot blend powder coating material includes, for example, a fluorine-containing copolymer having a crosslinkable reactive group such as partially fluorinated polyester and a curing agent that crosslinks with the crosslinkable reactive group. It is a coating composition obtained by adding a pigment to this and melting and kneading it to a ratio of 98/2, and by using this electrostatic coating of aluminum building materials such as aluminum sashes, powder coating with excellent weather resistance It is supposed to be formed on aluminum building materials.

  However, when a hot blend powder coating is used in this way, the coating component formed in accordance with the blend ratio of the coating composition is uniformly distributed in the powder coating formed thereby, and the entire film thickness direction is Therefore, since the polyester component and the fluorine component corresponding to the blending ratio of the coating composition are always present, this causes a cost increase. By forming a powder coating by powder coating using a dry blend powder coating of paint and fluorine coating, by distributing the powder coating at a high density on the surface side in the film thickness direction Fluorine paint component high-density distribution area that imparts weather resistance to the paint film and polyester paint composition that imparts impact resistance to the paint film by distributing the polyester paint component densely on the substrate side in the film thickness direction Powder coating method so as to comprise a high density distribution area, i.e., has already been proposed building materials, such as electrostatic coating method and aluminum building materials.

International Publication WO01 / 025346 Japanese Patent Application No. 2009-70450

  According to Patent Document 2, on the basis of the high and low temperature difference of heat melting, in the baking process, the low temperature side polyester paint component to be pre-melted can be arranged in the lower layer, and the fluorine paint to be subsequently melted can be arranged on the surface side. As a powder coating film for building materials, a high-density distribution area of the fluorine paint component that imparts weather resistance to the paint film by distributing the fluorine paint component on the surface side in the film thickness direction and a polyester paint on the base side in the film thickness direction Polyester paint component that imparts impact resistance to the coating film by distributing the components at a high density can be provided with a high density distribution region, but in this case, the polyester paint and fluorine paint are incompatible with each other. When the polyester coating component and the fluorine coating component are arranged to repel each other due to their incompatibility on the surface of the powder coating film, In addition to formation, the surface roughness of the powder coating film can be ensured, and the surface roughness combined with the refractive index of each paint component makes the powder coating film a matte (matte) surface. Therefore, it has been found that the surface always has a matte tone without adding a matting agent that causes deterioration of the coating film.

  The present invention has been made in view of such circumstances, and the solution problem is powder coated aluminum which is suitable for outdoor use by ensuring impact resistance and weather resistance and has a mat-like surface to improve the appearance of use. To provide building materials.

  In accordance with the above-mentioned problems, the present invention is a powder coating film in which powder coating, that is, electrostatic coating, is applied using a dry blend powder coating of a polyester coating and a fluorine coating that are incompatible and heat-melting at different temperatures. Fluorine paint component high-density distribution area that imparts weather resistance to the coating film in which the fluorine paint component is densely distributed on the surface side in the film thickness direction based on the above-mentioned high and low different temperatures of heat melting, and a film thickness direction base By providing a polyester paint component high density distribution area that imparts impact resistance to the coating film in which the polyester paint component is densely distributed on the side, it is suitable for outdoor use by ensuring impact resistance and weather resistance and the above non-phase The glossiness based on solubility is provided with a matte surface having a glossiness of 25 to 40% (measurement angle of 60 °) to improve the use appearance, that is, according to claim 1 Invention An aluminum building material having a powder coating film formed by powder coating of a dry blend powder coating of polyester paint and fluorine paint having a high melting temperature and a low melting temperature, which is incompatible, and the powder coating film By distributing the fluorine paint component in high density on the surface side in the thickness direction and providing the paint film with weather resistance, and by distributing the polyester paint component in high density on the base in the film thickness direction. For outdoor use, characterized in that it is formed with a polyester paint component high-density distribution region imparting impact resistance to the coating film, and a matte surface with a glossiness of 25 to 40% at a measurement angle of 60 ° Powder-coated aluminum building material.

  In addition to the above, the invention described in claims 2 to 4 is characterized in that the powder coating film can exhibit good coating film adhesion regardless of the ground, so that an aluminum building material for outdoor use is used. According to the invention of claim 2, the powder coating undercoat is made of an aluminum extrusion molding material or aluminum so that each of the powder coating undercoats has a preferable form exhibiting good coating adhesion. The powder coating aluminum building material for outdoor use according to claim 1, characterized in that it is an anodized film formed on a plate material. The invention according to claim 3, wherein the base of the powder coating film is extruded with aluminum. The powder coating aluminum building material for outdoor use according to claim 1, characterized in that it is formed as a chemical conversion film formed on a molding material or an aluminum plate material. , Anode formed on aluminum extrusion or aluminum plate Is obtained by the outdoor use of powder coating aluminum building material according to claim 1, characterized in that the electrodeposition coating and electrodeposition coating film to the reduction coating.

  The present invention uses each of these as the gist of the invention as means for solving the above problems.

  Since the present invention is configured as described above, the invention described in claim 1 is a powder coating using a dry blend powder coating of polyester paint and fluorine paint which is incompatible and heat-melted at high and low different temperatures. Fluorine paint component high-density distribution region that gives weather resistance to the paint film in which the fluorine paint component is distributed at high density on the surface side in the film thickness direction based on the above-mentioned high and low different temperature of heat melting And a polyester paint component high-density distribution area that imparts impact resistance to the coating film in which the polyester paint component is densely distributed on the substrate side in the film thickness direction, ensuring impact resistance and weather resistance for outdoor use A powder coated aluminum building material that is suitable for use and has a glossy surface with a glossiness of 25 to 40% (measuring angle 60 °) based on the above incompatibility and high quality and good use appearance. It can be.

  In addition to the above, the invention described in claims 2 to 4 can make the base of the powder coating film of an aluminum building material used outdoors have a preferable form exhibiting good adhesion.

It is the graph and conceptual diagram which show the relationship between atmospheric heating and the change of dry blend powder coating material. It is a photograph of the powder coating film surface (before baking). It is a photograph of the powder coating film surface (after baking). It is a graph which shows the color tone change result after the accelerated weathering test by a metal weather tester. It is a graph which shows the gloss retention result after the accelerated weather resistance test by a metal weather testing machine. It is a graph which shows the color change result after the accelerated weather resistance test by a sunshine weather tester. It is a graph which shows the gloss retention result after the accelerated weather resistance test by a sunshine weather tester.

  Hereinafter, the present invention will be described in more detail. The aluminum building material of the present invention is obtained by, for example, applying a chemical conversion film formed on an aluminum extrusion molding material or an aluminum plate material, in this example, a hexavalent chromium chemical conversion treatment It has a powder coating film formed by powder coating with the formed chemical film as a base, and the powder coating is made incompatible with polyester paint and fluorine paint with high and low heat melting temperature. In this case, the powder coating film imparted weather resistance to the coating film by distributing the fluorine coating component at a high density on the surface side in the film thickness direction. Fluorine paint component high-density distribution area, polyester paint component high-density distribution area that imparts impact resistance to the coating film by high-density distribution of the polyester paint component on the substrate side in the film thickness direction, and a measurement angle of 60 ° There glossiness as those formed with 25% to 40% and the matte surface.

  The powder coating film is formed by dry blending a polyester paint and a fluorine paint at a predetermined blending ratio and performing powder coating, so that a part of the powder coating film becomes 100%. However, when the polyester paint component and the fluorine paint component are seen as the structure of the powder coating film, the polyester paint component is dense on the substrate side in the film thickness direction and the fluorine paint component is dense on the surface side in the film thickness direction. As a result, both have different distribution densities on the base side and the surface side.

  Although the mechanism is not necessarily clear, the polyester paint and the fluorine paint exist in the dry blend blending stage and the powder coating stage in a state of being uniformly mixed at the blend ratio of the dry blend. Since each fluorine paint has an indefinite shape, the coating layer in the powder coating stage for aluminum building materials has a space between the paint particles (the coating layer is a powder coating). However, since the polyester paint and the fluorine paint have different heat melting temperatures, the former is low and the latter is high, the pre-melted polyester paint sews and fluidizes the voids in the fluorine paint. When the weight of polyester paint or aluminum building material is painted and suspended and baked, the air in the gap is released and the gap is decompressed, etc. Thus, while incorporating some of the fluorine paint, while set to the base side, a fluorine coating is followed melted, it is seen to be due to the aggregate on the surface side of the polyester coating that preceded melted.

  Incidentally, regarding the SP value of polyester and fluorine (difference in solubility parameter), it is assumed that when ΔSP> 1, it is easier to separate and the smaller SP value is easier to coordinate to the gas phase side (surface layer side). However, for example, the SP value of the low-temperature polyester paint in the powder paint is 10.7, and the SP value of the fluorine paint is 8 to 9, so ΔSP is 1.7 to 2.7, and the SP value is ΔSP. > 1. Therefore, from the SP value, it is recognized that the fluorine paint is arranged on the surface side on the surface layer at the time of heat melting.

  The polyester paint component and the fluorine paint component forming the powder coating film are present according to the blending ratio (weight ratio) of the dry blend. The paint component is quantitatively mixed with the polyester paint component, for example, 3: 7. Less, the fluorine paint component can be increased in quantity and can be equally divided as 5: 5. Generally, however, the polyester paint component is quantitatively added as in 7: 3, 8: 2. In many cases, even if the amount of the fluorine paint component is reduced, it is possible to form a fluorine-based high-density distribution area in which the fluorine paint component is densely distributed on the surface side and to ensure weather resistance. In the film, it is preferable to increase the polyester coating component and decrease the fluorine coating component in order to secure the weather resistance while suppressing an increase in the production cost of the powder coating film, and thus the aluminum building material.

This can be explained by Table 1 in which the distribution in the film thickness direction of the polyester paint component and the fluorine paint component is measured. Table 1 shows that the surface layer portion of the powder coating film having a film thickness of 42 μm is infrared in the film thickness direction. Absorbance is measured by spectroscopic method, the peak height ratio of fluorine paint / polyester paint (1700/1720 cm ⁻¹ ) is determined, and a calibration curve is created based on the fluorine paint ratios of 0% and 100%. This shows the result of calculating each time twice.

  According to Table 1, when polyester (P): fluorine (F) = 5: 5 at a depth of 0.5 μm in the film thickness direction from the surface, fluorine is 93% (average value), P: F = 7: 3 is 87% (same), P: F = 8: 2 is 76% (same), P: F = 3: 7 is 95% (same), and 11 from the surface in the film thickness direction. At each depth position of -19 μm, when P: F = 5: 5, fluorine was 68% and 95% (measured twice), and 34-42 μm was 64% and 98% (same). It was. Regardless of the blending ratio, in the powder coating film, the fluorine paint component is densely distributed on the surface side in the film thickness direction, and the polyester paint component is densely distributed on the lower base side. Therefore, it is found that the polyester coating component and the fluorine coating component are not laminated in the powder coating film, but are densely distributed. In addition, about the said P: F = 7: 3, when the fluorine on the back surface was measured, the fluorine was 2% (same). Therefore, the remaining 11% excluding the total of 87% of 0.5 μm and 2% of the back surface is distributed in the middle of the thickness direction of the powder coating film, and the distribution density decreases in the thickness direction. It is inferred that

  On the other hand, the photographs shown in FIG. 2 and FIG. 3 are photographs of the surface of the powder coating film before and after the baking process, and FIG. 2 shows that the polyester paint is added with white and the fluorine paint is added with pigment. A photograph of the surface colored in gray, dry blended with the blending ratio of 7: 3, and then applied with electrostatic coating (gun distance 30 cm), FIG. 3 is further baked at 180 ° C. for 20 minutes (atmosphere heating) It is a photograph of the surface which gave).

  FIG. 2 shows a surface state in which there are many white polyester paints depending on the blending ratio of the dry blend and there is little gray, but in FIG. 3, the surface state in which a large amount of gray color appears on the surface and the white color is reduced. Therefore, it is found that the fluorine paint component in the powder coating film forms a high-density distribution region on the surface side.

  The surface of the powder coating film can be made into a matte tone by dry blending the polyester paint and the fluorine paint, particularly a matte tone having a glossiness of 25 to 40% at a measurement angle of 60 °.

  Polyester paints and fluorine paints have different heat melting temperatures and are incompatible with each other, so the polyester paints and fluorine paints harden in a state where they repel each other during surface formation by baking. The powder coating film is formed as a result of forming the surface roughness, the surface roughness exerts the light irregular reflection function, and the refractive index of the polyester coating component and the fluorine coating component of the powder coating film promotes the irregular reflection function. It is recognized that this leads to a matte surface with the above glossiness.

  That is, high weather resistance polyester powder coating (measured film thickness 62 μm), thermosetting fluorine powder coating (measured film thickness 64 μm), solvent-based thermoplastic fluorine coating (measured film thickness 25 μm), the polyester paint and fluorine paint Table 2 shows the results obtained by applying each powder coating with a dry blend powder coating (measured film thickness 60 μm) and measuring the surface roughness and glossiness of the powder coating film. The film thickness meter for measuring the average film thickness is MP-30 manufactured by Fischer Instruments Co., Ltd., the surface roughness meter is Surfcorder SE500 manufactured by Kosaka Laboratory, and the gloss meter is GMX-102 manufactured by Murakami Color Research Laboratory Co., Ltd. An angle of 60 ° was used.

  High weather resistance polyester powder coating has a surface roughness of 0.3μm, glossiness of 80%, thermosetting fluorine powder coating has a surface roughness of 0.5μm, glossiness of 66%, solvent-based thermoplastic fluorine coating As a result, the surface roughness of the dry blend powder coating material of the polyester paint and the fluorine paint is 1.0 μm, and the glossiness is 30%. It was found that the matte tone of the powder coating surface of the dry blend powder coating mainly depends on the surface roughness and the glossiness.

  Generally, the glossiness of a powder coating film of a high weather resistance polyester powder coating used for aluminum building materials is 80%. In this case, since the gloss value becomes large, a matting agent is added to the coating for commercialization. In order to reduce the gloss value and make the surface matte, the use of a matting agent is a cause of deterioration of the powder coating film. Depending on the dry blend powder coating of polyester paint and fluorine paint, In addition to ensuring the weather resistance by the high-density distribution region of the fluorine paint component, the surface of the powder coating film can be made into a matte tone without using a matting agent, so that the aluminum building material can be of high quality.

  The gloss of the polyester paint and fluorine paint dry blend powder paint may show some variation depending on the measurement location, film thickness, measuring equipment, etc., but generally the lower limit is 25% and the upper limit is 40%. It can be within range.

  The film thickness of the powder coating film may be an average within a range of 60 μm to 100 μm according to a conventional method, whereby the powder coating film has a high quality with weather resistance and matte surface suitable for outdoor use. Can be applied to various aluminum products such as aluminum sashes, aluminum curtain walls, aluminum verticals, and aluminum gates.

  The production method of the aluminum building material having the powder coating described above includes a paint dry blending process in which the above polyester paint and fluorine paint are dry blended to form a dry blend powder paint, and an aluminum extrusion forming an object of the aluminum building material. An electrostatic coating process in which the dry blend powder coating is powder-coated on a material or an aluminum plate, and the powder-coated object is thermally melted at a high temperature of, for example, about 200 ° to increase the polyester coating component It is assumed that it has undergone a heating process of atmospheric heating that forms a density distribution area and a fluorine paint component high density distribution area. At this time, the electrostatic coating process and the heating process are performed by applying a hanger on the conveyor rail to coat the aluminum building material. Conveying the product through the spray booth and baking booth, powder coating at the spray booth, and powder in accordance with the usual method to heat the atmosphere at the baking booth It is sufficient to perform instrumentation. The dry blending of polyester paint and fluorine paint should be done at a prescribed blend ratio before supplying to the spray booth, and overspray paint in the spray booth should be recovered and reused to eliminate paint loss. It is preferable to make it.

  A pigment coating is added to a polyester paint or a fluorine paint, and the powder coating is colored, the base of the powder coating is an anodized film formed on an aluminum extrusion molding material or an aluminum plate, In carrying out the present invention, the base material of the powder coating film is an electrodeposition coating film obtained by electrodeposition coating on an anodized film formed on an aluminum extrusion molding material or an aluminum plate material. , Fluorine paints, blended powder paints thereof, fluorine paint component high density distribution region, polyester paint component high density distribution region, each specific shape, structure, material, production method, conditions, etc. of the matte surface As long as it is not contrary to the gist of the present invention, various forms can be adopted.

  A 6063S-T5 material with a plate thickness of 0.2 × 6 × 17 cm, a polyester powder coating as a low-temperature side base material colored in the same color of gray with a common pigment, and a fluorine powder as a high-performance side functional coating material The paint is dry blended with the blending ratio of polyester powder paint 7 and fluorine powder paint 3 and electrostatically applied, and then heated to ambient temperature from room temperature to 180 ° C to make a sample, which is used as a metal weather tester and sunshine weather test. An accelerated weather resistance test was conducted by a machine, and the former was taken out every 120 hours and the latter every 500 hours, and the color change and gloss retention were measured with a color difference meter and a gloss meter, respectively. 4 and 5 show the results of the accelerated weather resistance test using the metal weather tester, and FIGS. 6 and 7 show the results of the accelerated weather resistance test using the sunshine weather tester.

  The blending ratio of the dry blend was the same as in Example 1 except that the polyester powder paint 5 and the fluorine powder paint 5 were used. Similarly, the results are shown in FIGS. 4 and 5 and FIGS.

  The blending ratio of the dry blend was the same as in Example 1 except that the polyester powder paint 3 and the fluorine powder paint 7 were used. Similarly, the results are shown in FIGS. 4 and 5 and FIGS.

Comparative Example 1

  The powder coating material was the same as that of Example 1 except that the fluorine powder coating material was not used and only the polyester powder coating material colored in gray with a pigment was electrostatically applied. Similarly, the results are shown in FIGS. 4 and 5 and FIGS.

Comparative Example 2

  The powder coating material was the same as Example 1 except that the polyester powder coating material was not used and only the fluorine powder coating material colored in gray with a pigment was electrostatically applied. Similarly, the results are shown in FIGS. 4 and 5 and FIGS.

  The color difference change by the metal weather tester in FIG. 4 is only for the polyester powder paint sample of Comparative Example 1, and ΔE = 1.5 when 300 hours have elapsed after the start of the test, and ΔE = 7. In contrast, the samples obtained by dry blending the polyester powder coating materials and the fluorine powder coating materials of Examples 1 to 3 all had ΔE = 1.0 or less after 500 hours, and Comparative Example 2 It was almost the same as the sample of only the fluorine powder coating.

  Similarly, the gloss retention by the metal weather tester of FIG. 5 is about 85% at the time of 360 hours after the start of the test and slightly higher than 20% at the time of 500 hours for the sample of the polyester powder paint of Comparative Example 1 only. On the other hand, the samples obtained by dry blending the polyester powder coatings of Examples 1 to 3 and the fluorine powder coating were all about 85% after 480 hours, and the fluorine powder of Comparative Example 2 It was only slightly lower than the paint-only sample.

  The change in color difference by the sunshine weather tester in FIG. 6 is not much different when 1500 hours have elapsed since the start of the test, and all of them fall within ΔE = 1.0 or less, but in the sample of only the polyester powder paint of Comparative Example 1. Is about ΔE = 1.25 after 2000 hours from the start of the test and ΔE = 1.5 after 2500 hours, whereas the polyester powder coating and the fluorine powder coating of Examples 1 to 3 The dry blended samples had ΔE = 1.0 or less at the time point of 2000 hours and 2500 hours, which was slightly higher than the sample of the comparative example 2 containing only the fluorine powder coating.

  Similarly, the gloss retention rate by the sunshine weather tester in FIG. 7 is not much different in the sample of only the polyester powder paint of Comparative Example 1 as it is slightly less than 100% after 1000 hours from the start of the test. The polyester powder coating materials and fluorine powders of Examples 1 to 3 were about 75% at 1500 hours after the start of the test, about 45% after 2000 hours, and several% after 2500 hours. All of the samples obtained by dry blending the paint were about 90% at the time point of 2500 hours, which was slightly lower than the sample of the fluorine powder paint of Comparative Example 2 alone.

  From the above, the powder coating of aluminum building materials formed by powder coating of dry blend powder coating of polyester paint and fluorine paint has high weather resistance due to the high density distribution area of fluorine paint component on the surface side in the film thickness direction. It was revealed that the weather resistance did not vary greatly depending on the blending ratio of the dry blends of Examples 1 to 3.

Claims (4)

  An aluminum building material having a powder coating film formed by powder coating of a dry blend powder coating of polyester paint and fluorine paint having a high melting temperature and a low melting temperature, which is incompatible, and the powder coating film By distributing the fluorine paint component in high density on the surface side in the thickness direction and providing the paint film with weather resistance, and by distributing the polyester paint component in high density on the base in the film thickness direction. For outdoor use, characterized in that it is formed with a polyester paint component high-density distribution region imparting impact resistance to the coating film, and a matte surface with a glossiness of 25 to 40% at a measurement angle of 60 ° Powder coated aluminum building material.   2. The powder-coated aluminum building material for outdoor use according to claim 1, wherein the base of the powder coating film is an anodized film formed on an aluminum extrusion molding material or an aluminum plate material.   2. The powder-coated aluminum building material for outdoor use according to claim 1, wherein the powder coating base is a chemical conversion coating formed on an aluminum extruded material or an aluminum plate.   2. The powder coating for outdoor use according to claim 1, wherein the powder coating base is an electrodeposition coating obtained by electrodeposition coating on an anodized film formed on an aluminum extrusion molding material or an aluminum plate. Aluminum building material.