Coating film manufacturing method and coating film measurement method

Abstract

To provide a coating film manufacturing method which cn realize objective coating film assurance with respect to an entire outer wall including a ceiling part.SOLUTION: A coating film manufacturing method includes a process of applying an urea resin coating composition onto a base containing a substantially smooth conductive metallic part to form an urea resin layer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a coating film and a method for measuring a coating film. [Background technology]

[0002] Architectural paints hold the largest share of the domestic paint market. Within this architectural paint market, home renovation applications account for the largest proportion. As the home renovation market is a growing market, many renovation companies have entered the market. When renovating exterior walls, clients want to improve the durability of the paint film and extend the span of expensive home renovations as much as possible. In response to this demand, renovation companies are differentiating themselves by using durable paints containing tetrafluoroethylene resins and offering paint film guarantees.

[0003] However, the coating guarantees that have been implemented so far have been based on conceptual criteria, such as whether or not there is a significant change in the visual appearance, and are therefore lacking in objectivity, and have not been fully trusted by clients. There is a need for coating guarantees that are based on quantitative and clear criteria.

[0004] In the exterior walls of houses, the sealant areas where the wall panels join together are filled with highly flexible silicone-based materials to prevent water penetration. When conventional exterior wall paint is applied over the sealant areas, the paint film has poor adaptability to the deformation of the sealant, resulting in the surface of the paint film cracking and peeling. As a result, the sealant areas have often been excluded from the paint film warranty. There is a need for painting technology and film thickness measurement technology that can guarantee the paint film for the entire exterior wall, including the sealant areas.

[0005] Patent Document 1 discloses a method for measuring the thickness of a coating film including a conductive primer layer using an eddy current film thickness meter. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-206412 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a method for manufacturing a coating film that can provide objective coating film guarantees for the entire exterior wall, including the sealing portion. [Means for solving the problem]

[0008] The present inventors have found that the above problems can be solved by applying a urea resin coating composition onto a substrate including a substantially smooth conductive metal portion, and have completed the present invention.

[0009] That is, the present invention relates to a method for producing a coating film, which comprises a step of applying a urea resin coating composition onto a substrate including a substantially smooth conductive metal portion to form a urea resin layer.

[0010] It is preferable that the step between the conductive metal portion and the underlying layer other than the conductive metal portion is 2000 μm or less.

[0011] The conductive metal portion is preferably formed by a conductive metal member embedded in a substrate.

[0012] Preferably, the conductive metal is stainless steel.

[0013] Preferably, the substrate includes a surface of sealant filled into the joints of the siding boards.

[0014] The wet thickness of the urea resin layer is preferably 50 μm or more.

[0015] The dry thickness of the resulting coating film is preferably 50 μm or more.

[0016] Furthermore, it is preferable to include a step of forming a primer layer on the surface of the base before the step of forming the urea resin layer.

[0017] The present invention also relates to a film thickness measurement method including the steps of forming a coating film by the above-described production method and measuring the film thickness of the formed coating film with an eddy current film thickness meter or an electromagnetic film thickness meter. [Effects of the Invention]

[0018] According to the coating film manufacturing method of the present invention, a coating film can be obtained that can provide objective coating film guarantees for the entire exterior wall, including the sealing portion. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 2 is a cross-sectional view showing a coating film during film thickness measurement. [Figure 2] 1 is a schematic top view of a substrate consisting of a siding board, a conductive metal part, and a sealant. DETAILED DESCRIPTION OF THE INVENTION

[0020] <<Method for Producing a Coating Film>> The method for producing a coating film of the present invention is characterized by comprising a step of applying a urea resin coating composition onto a substrate containing a conductive metal portion to form a urea resin layer.

[0021] <Base> The base material is not particularly limited as long as it is one used in building materials, but is preferably a material with low or no conductivity, and is preferably non-metallic. Non-metallic materials include inorganic materials such as concrete, calcium silicate board, ALC board, gypsum board, and slate board, fibrous materials such as glass wool, rock wool, and cellulose fiber, resin materials such as polyethylene foam, polystyrene foam, polyurethane foam, and polyvinyl chloride, wood materials, and any combination thereof.

[0022] The form of the substrate is not particularly limited and may be a siding board, a heat insulating material, or the like, but a siding board is preferred, and a siding board containing cement, a fiber material, a wood material, vinyl chloride, or the like is more preferred.

[0023] When the substrate is a siding board, it is preferable that the substrate further includes the surface of a sealant filled in the joints of the siding board. In other words, it is preferable that a urea resin layer is formed on the surface of the sealant. Generally, when installing siding boards, a sealant is filled into the joints between adjacent siding boards to prevent water from entering through the gaps (joints). Highly flexible materials such as silicone resins are often used as sealants. Conventionally, when a paint is applied over a sealant filled in the joints of siding boards, the paint film has poor adaptability to deformation of the sealant, resulting in cracking and peeling of the paint film surface. Therefore, the paint film on the surface of the sealant has not been covered by the warranty. The manufacturing method of the present invention can produce a highly flexible paint film that can adapt to deformation of the sealant. Therefore, the paint film on the surface of the sealant can also be covered by the warranty.

[0024] The width of the joints of the siding boards is generally 10 to 20 mm, and preferably 10 to 12 mm.

[0025] <Conductive Metal Portion> The substrate includes a substantially smooth conductive metal portion. By including the conductive metal portion in the substrate, the thickness of the coating film can be precisely measured with an electromagnetic film thickness gauge or an eddy current film thickness gauge, even on exterior walls that are not conductive or magnetic, such as concrete or siding boards. Examples of conductive metals include, but are not limited to, stainless steel, copper, aluminum, zinc, magnesium, silver, chromium, and tin. The surface area of ​​the conductive metal portion is not particularly limited as long as the film thickness of the urea resin layer can be measured with an electromagnetic film thickness gauge or an eddy current film thickness gauge, but is preferably 0.8 cm. 2 More than 1.5cm is preferable. 2 The upper limit is not particularly limited, but is generally 3.1 cm. 2 The following is the result.

[0026] By making the conductive metal portion substantially smooth, the thickness of the coating film can be measured accurately. Specifically, "substantially smooth" means that the arithmetic mean roughness Ra of the conductive metal portion is 0.3 μm or less, and preferably 0.2 μm or less.

[0027] The conductive metal portion preferably has a small step between it and the underlying portion other than the conductive metal portion. By reducing this step, the film thickness of the urea resin layer can be measured using an electromagnetic film thickness meter or an eddy current film thickness meter. The step is preferably 2000 μm or less, and more preferably 1000 μm or less.

[0028] The color of the conductive metal part is not particularly limited and may be the color of the material itself, but it is preferable to make it the same color as the base, which can avoid the conductive metal part being conspicuous and damaging the design even when a transparent coating film is formed.

[0029] The method for forming the conductive metal portion is not particularly limited, and examples thereof include a method of embedding a conductive metal member in a substrate and a method of forming a coating film containing a conductive metal on a substrate. However, the method of embedding a conductive metal member in a substrate is preferred because it allows for precise film thickness measurement. The form of the conductive metal member is not particularly limited, and examples thereof include bolts, screws, screws, nails, etc. These conductive metal members are embedded in the substrate so that a portion of them is exposed, as shown in Figure 1. As shown in Figure 2, the portion exposed from the substrate becomes the conductive metal portion. For example, when a screw is used as the conductive metal member, the screw is screwed into the substrate, and the head of the screw exposed on the surface becomes the conductive metal portion.

[0030] When the substrate further includes the surface of a sealant filled in the joints of the siding board, the distance between the surface of the sealant and the conductive metal part is preferably 20 to 300 mm, more preferably 20 to 150 mm, and even more preferably 20 to 50 mm. By positioning the conductive metal part within this range, it is possible to precisely measure the film thickness of the sealant part, which is generally prone to cracking.

[0031] <Urea Resin Paint Composition> The urea resin paint composition used in the present invention is not particularly limited as long as it can form a urea resin layer on a substrate, and examples thereof include a two-component composition consisting of an isocyanate compound and an amine compound, a one-component composition in which an isocyanate compound and an amine compound are mixed together without reacting with each other, and a composition containing a resin with a urea structure obtained by previously reacting an isocyanate compound with an amine compound.

[0032] When using a two-component composition, the isocyanate compound and amine compound are mixed just before painting, and after painting, a urea structure is formed through a chemical reaction. There is a wide range of isocyanate compounds and amine compounds to choose from, making it easy to control the quality of the paint film.

[0033] In one-liquid compositions, the isocyanate compound and the amine compound are encapsulated to prevent contact between them, making them one-liquid, and they are easy to handle and to control the quality.

[0034] A composition containing a resin with a urea structure, which has been prepared by reacting an isocyanate compound with an amine compound in advance, is easy to handle and can be made into a one-component paint because it contains a urea resin that has already been reacted. Furthermore, by making this composition into an emulsion-type water-based paint that incorporates the urea resin, it is possible to reduce the environmental impact while maintaining the quality of the urea resin.

[0035] The urea resin coating composition may be a solvent-based coating or a water-based coating, and the urea resin layer is formed by applying the urea resin coating composition by a common method such as spraying, brushing, or roller application.

[0036] The thickness of the urea resin layer formed in one coating step is preferably 50 μm or more, more preferably 100 μm or more, and even more preferably 150 μm or more, in wet film thickness. The wet film thickness is measured by applying a wet gauge to the smooth part of the base to which the urea resin layer is applied. If the base does not have a smooth part, the film thickness can be measured by the coating weight per unit area. The coating weight is 50 g / m2, in wet film thickness. 2 More than 100g / m 2 More preferably, 150 g / m 2 When a plurality of urea resin layers are formed, it is preferable that the wet film thickness of each urea resin layer is within the above-mentioned range.

[0037] The coating film formed by the method of the present invention has excellent durability because it is formed from a urea resin paint. When the substrate includes the surface of a sealant, the coating surface on the sealant preferably has an expected service life of 15 years or more. Furthermore, the portion other than the sealant surface preferably has an expected service life of 30 years or more.

[0038] <Primer Layer> It is preferable to include a step of forming a primer layer on the surface of the base prior to the step of forming a urea resin layer on the base. The primer layer can be formed by applying a silicone-based primer, an epoxy-based primer, or the like to the base. The thickness of the primer layer, in wet film thickness, is preferably 50 μm or more, more preferably 80 μm or more, and even more preferably 120 μm or more. When the coating film of the present invention has a primer layer, a urea resin layer can be laminated on the primer layer. Furthermore, multiple urea resin layers may be laminated, and examples include coating films having a base, a primer layer, a urea resin layer as an intermediate coat, and a urea resin layer as a top coat.

[0039] <Film Thickness> The dry film thickness of the coating is preferably 50 μm or more, more preferably 100 μm or more, and even more preferably 150 μm or more. The dry film thickness can be measured using an electromagnetic film thickness meter or an eddy current film thickness meter. The coating thickness here refers to the total film thickness present on the base, and if there is a primer layer or multiple urea resin layers, it is the total thickness of these layers.

[0040] <<Film Thickness Measurement Method>> The film thickness measurement method of the present invention relates to a film thickness measurement method comprising the steps of forming a coating film containing a urea resin layer and measuring the film thickness of the formed coating film with an eddy current film thickness meter or an electromagnetic film thickness meter. In the step of forming a coating film containing a urea resin layer, a coating film containing a urea resin layer is formed using the base and coating composition described above in relation to the coating film manufacturing method.

[0041] In the film thickness measurement process, the dry film thickness of the dried coating film, including the urea resin layer, is measured using a film thickness gauge. When measuring the film thickness, the detection head of the film thickness gauge is pressed against the conductive metal portion of the substrate, as shown in Figure 1. The film thickness gauge used is either an eddy current film thickness gauge or an electromagnetic film thickness gauge. When using an eddy current film thickness gauge, the coating film is measured based on the electrical resistance between the detection head and the conductive metal portion. When using an electromagnetic film thickness gauge, the coating film is measured based on the magnetism between the detection head and the conductive metal portion. The choice of whether to use an eddy current film thickness gauge or an electromagnetic film thickness gauge can be made depending on the conductivity and magnetism of the conductive metal portion. For example, when the conductive metal portion is made of stainless steel, either an eddy current film thickness gauge or an electromagnetic film thickness gauge may be used. When the conductive metal portion is made of aluminum or copper, an eddy current film thickness gauge is preferably used.

[0042] The substrate and film thickness measurement method of the present invention will be described with reference to the drawings. Fig. 1 is a cross-sectional schematic diagram of a coating film during film thickness measurement. A conductive metal member 20 is embedded in a substrate 10. A urea resin layer 30 is laminated on the substrate 10 and the conductive metal member 20. The detection head 41 of a film thickness meter 40 is pressed against the location of the conductive metal member 20 in the substrate to measure the film thickness of the urea resin layer.

[0043] 2 is a schematic top view of a case where a siding board is used as the base material. A conductive metal portion 60 exists on the siding board 70. A sealant 50 is filled between adjacent siding boards 70. [Example]

[0044] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. Furthermore, unless otherwise specified, "parts" means parts by weight.

[0045] (1) Example 1 (1-1) Application of sealants and metal screws A sealant (product name: Resilience Sealant, a modified silicone sealant manufactured by PL Japan Co., Ltd.) was applied to the grooves of the siding board. A metal screw (product name: Resilience Film Thickness Measurement Pin, a stainless steel screw manufactured by PL Japan Co., Ltd.) was screwed into the surface of the siding board (50 mm from the groove of the siding board).

[0046] (1-2) Undercoat A primer (product name: Resilience Hybrid Binder Si, a silicone-based primer manufactured by PL Japan Co., Ltd.) was applied to cover the siding board surface and the areas where the sealant had been applied, and it was confirmed that the wet film thickness was 100 μm or more.

[0047] (1-3) Undercoat Five hours after the primer coating, a single coat of urea resin paint (product name: Resilience Urea, a one-component urea resin paint manufactured by PL Japan Co., Ltd.) was applied as an undercoat, and the wet film thickness was measured, confirming that it was 150 μm or more.

[0048] (1-4) Top coat Sixteen hours after the primer coat was applied, a urea resin paint (Resilience Urea, a one-component urea resin paint manufactured by PL Japan Co., Ltd.) was applied once as a top coat, and the wet film thickness was measured and confirmed to be 150 μm or more. The primer coat and top coat were the same paint, and a total of two coats were applied.

[0049] (1-5) Film Thickness Measurement One day after applying the top coat, the thickness of the dry coating was measured using an electromagnetic coating thickness meter (product name: SWT-9300, manufactured by Sanko Electronics Laboratory) and found to be 170 μm. Furthermore, visual evaluation of the surface condition of the coating revealed no significant changes in the design.

[0050] (1-6) Evaluation of coating film This siding board was placed in a Super UV accelerated weathering tester (product name: iSuper UV Tester, manufactured by Iwasaki Electric Co., Ltd.), and after 2000 hours, the condition of the coating on the siding board surface and the sealant surface was observed. No significant decrease in gloss was observed in the general wall surface that was not on the sealant. In addition, no abnormalities in appearance such as cracks were observed in the coating on the sealant.

[0051] The measurement conditions for the Super UV accelerated weathering tester (Iwasaki Electric Co., Ltd., Eye Super UV Tester) are as follows: Wavelength: 295~450nm UV irradiance: 150mW / cm 2 BP temperature: 63℃

[0052] (2) Example 2 (2-1) Application of sealants and metal screws A sealant (product name: Resilience Sealant, a modified silicone sealant manufactured by PL Japan Co., Ltd.) was applied to the grooves of the siding board. A metal screw (product name: Resilience Film Thickness Measurement Pin, a stainless steel screw manufactured by PL Japan Co., Ltd.) was screwed into the surface of the siding board (80 mm from the groove of the siding board).

[0053] (2-2) Undercoat A primer (product name: Resilience Hybrid Binder Si Clear, a silicone-based primer manufactured by PL Japan Co., Ltd.) was applied to cover the siding board surface and the areas where the sealant had been applied, and it was confirmed that the wet film thickness was 100 μm or more.

[0054] (2-3) Undercoat Five hours after the primer coating, a single coat of urea resin paint (product name: Resilience Urea, a one-component urea resin paint manufactured by PL Japan Co., Ltd.) was applied as an undercoat, and the wet film thickness was measured, confirming that it was 150 μm or more.

[0055] (2-4) Top coat Sixteen hours after the primer coat was applied, a urea resin paint (Resilience Urea, a one-component urea resin paint manufactured by PL Japan Co., Ltd.) was applied once as a top coat, and the wet film thickness was measured and confirmed to be 150 μm or more. The primer coat and top coat were the same paint, and a total of two coats were applied.

[0056] (2-5) Film Thickness Measurement One day after applying the top coat, the thickness of the dry coating was measured using an electromagnetic coating thickness meter (product name: SWT-9300, manufactured by Sanko Electronics Laboratory) and found to be 180 μm. Furthermore, visual evaluation of the surface condition of the coating revealed no significant changes in the design.

[0057] (2-6) Evaluation of coating film This siding board was placed in a Super UV accelerated weathering tester (product name: iSuper UV Tester, manufactured by Iwasaki Electric Co., Ltd.), and after 2000 hours, the condition of the coating on the siding board surface and the sealant surface was observed. No significant decrease in gloss was observed in the general wall surface that was not on the sealant. In addition, no abnormalities in appearance such as cracks were observed in the coating on the sealant.

[0058] (3) Comparative Example 1 (3-1) Preparation and painting of the base The sealant was applied, and the undercoat, intermediate coat, and top coat were applied in the same manner as in Example 1, except that the metal screws were not screwed in.

[0059] (3-2) Film Thickness Measurement One day after the top coat application, the thickness of the dry coating was measured using an eddy current coating thickness meter (product name: SWT-9300, manufactured by Sanko Electronics Laboratory), but the dry coating thickness could not be measured.

[0060] (3-3) Evaluation of coating film This siding board was placed in a Super UV accelerated weathering tester (product name: iSuper UV Tester, manufactured by Iwasaki Electric Co., Ltd.), and after 2000 hours, the condition of the coating on the siding board surface and the sealant surface was observed. No significant decrease in gloss was observed in the general wall surface that was not on the sealant. In addition, no abnormalities in appearance such as cracks were observed in the coating on the sealant.

[0061] (4) Comparative Example 2 (4-1) Application of sealants and metal screws As in Example 1, the sealant and metal screws were applied.

[0062] (4-2) Undercoat A primer (product name: 1-component Fine Sealer, epoxy sealer from Nippon Paint Co., Ltd.) was applied to cover the siding board surface and the areas where sealant had been applied, and the wet film thickness was measured, confirming that it was approximately 50 μm.

[0063] (4-3) Undercoat Three hours after applying the primer, a urethane paint (product name: 1-component Fine Urethane, manufactured by Nippon Paint Co., Ltd.) was applied, and the wet film thickness was measured, confirming that it was 150 μm or more.

[0064] (4-4) Top coat 15 hours after the undercoat application, a urethane paint (product name: 1-component Fine Urethane, urethane paint manufactured by Nippon Paint Co., Ltd.) was applied, and the wet film thickness was measured and confirmed to be 150 μm or more.

[0065] (4-5) Film Thickness Measurement One day after the top coat application, the thickness of the dry coating was measured using an eddy current coating thickness meter (product name: SWT-9300, Sanko Electronics Laboratory film thickness meter) and confirmed to be 180 μm.

[0066] (4-6) Evaluation of coating film This siding board was placed in a Super UV accelerated weathering tester (product name: iSuper UV Tester, manufactured by Iwasaki Electric Co., Ltd.), and after 2000 hours, the condition of the coating on the siding board surface and the sealant surface was observed. The gloss of the general wall surface, not on the sealant, had dropped significantly, becoming almost completely non-glossy. The coating was also severely cracked, with some peeling and falling off. Most of the coating on the sealant had also peeled off, revealing noticeable visual abnormalities.

[0067] (5) Comparative Example 3 (5-1) Application of sealant and metal tape A sealant (product name: Resilience Sealant, a modified silicone sealant manufactured by PL Japan Co., Ltd.) was applied to the grooves of the siding board. A 10 cm square piece of copper foil tape (Nitto copper foil tape, film thickness 0.03 mm) was attached to the surface of the siding board.

[0068] (5-2) Undercoat A primer (product name: Resilience Hybrid Binder Si, a silicone-based primer manufactured by PL Japan Co., Ltd.) was applied to cover the siding board surface and the areas where the sealant had been applied, and it was confirmed that the wet film thickness was 100 μm or more.

[0069] (5-3) Undercoat Five hours after the primer coating, a single coat of urea resin paint (product name: Resilience Urea, a one-component urea resin paint manufactured by PL Japan Co., Ltd.) was applied as an undercoat, and the wet film thickness was measured, confirming that it was 150 μm or more.

[0070] (5-4) Top coat Sixteen hours after the primer coat was applied, a single coat of urea resin paint (product name: Resilience Urea, a one-component urea resin paint manufactured by PL Japan Co., Ltd.) was applied as a top coat, and the wet film thickness was measured and confirmed to be 150 μm or more. The primer coat and top coat were the same paint, and a total of two coats were applied.

[0071] (5-5) Film Thickness Measurement One day after applying the top coat, the thickness of the dried coating was measured using an eddy current coating thickness meter (product name: SWT-9300, manufactured by Sanko Electronics Laboratory). The thickness varied greatly depending on the measurement location, with variations of over 50 μm. This is thought to be due to the lack of smoothness of the copper foil, which resulted in large variations in thickness due to uneven areas.

[0072] (5-6) Evaluation of coating film This siding board was placed in a Super UV accelerated weathering tester (product name: iSuper UV Tester, manufactured by Iwasaki Electric Co., Ltd.), and after 2000 hours, the condition of the coating on the siding board surface and the sealant surface was observed. No significant decrease in gloss was observed in the general wall surface that was not on the sealant. Furthermore, no abnormalities in appearance such as cracks were observed in the coating on the sealant.

[0073] (6) The results of Examples 1 and 2 and Comparative Examples 1 to 3 are summarized in Table 1. The criteria for each evaluation item are as follows:

[0074] (6-1) Flexibility of the coating film The condition of the coating film on the sealant was visually inspected for cracks and peeling and evaluated according to the following criteria. ◎ No change in the coating surface is observed No change in the coating surface is observed △ Slight changes are observed on the coating surface × Cracks, peeling, stickiness, etc. are observed on the coating surface

[0075] (6-2) Appearance of the coating The coating film was visually inspected to determine whether the smoothness was impaired or peeling was observed, and evaluated according to the following criteria. ◎ No change in the appearance of the coating No change in the appearance of the coating △ Changes in the appearance of the coating film are observed × Abnormalities are observed in the appearance of the coating

[0076] (6-3) Weather resistance of coating film Weather resistance was tested using Super UV and was determined by the loss of gloss of the coating. ◎ No change in gloss is observed (gloss retention rate of 70% or more) 〇 Almost no change in gloss is observed (gloss retention rate is 50% or more but less than 70%) △ Change in gloss is observed (gloss retention rate is 30% or more but less than 50%) × Gloss loss is observed (gloss retention rate less than 30%)

[0077] (6-4) Objective Film Thickness Measurement The dry film thickness was measured using a film thickness meter. The measurement was repeated for the same coating film, and the difference between the maximum and minimum values ​​was used to evaluate the film thickness according to the following criteria. ◎ The difference between the maximum and minimum values ​​is less than 2 μm The difference between the maximum and minimum values ​​is 2 μm or more and less than 5 μm △ The difference between the maximum and minimum values ​​is 5 μm or more and less than 50 μm × The difference between the maximum and minimum values ​​is 50 μm or more, or the film thickness cannot be measured

[0078] [Table 1]

[0079] In Comparative Example 1, no conductive member was used, so objective film thickness measurement was not possible. In Comparative Example 2, a paint containing urethane resin was used, so the flexibility and weather resistance of the coating film were insufficient. In Comparative Example 3, copper foil tape was used as the conductive member, so the smoothness of the conductive part was insufficient, making objective film thickness measurement impossible and weather resistance was slightly reduced. In Examples 1 and 2, the coating film had excellent flexibility, appearance, and weather resistance, and objective film thickness measurement was also possible. In Example 2, a clear (transparent) primer was used, so a transparent coating film was formed.

[0080] The present disclosure (1) is a method for producing a coating film, which includes a step of applying a urea resin coating composition onto a substrate including a substantially smooth conductive metal portion to form a urea resin layer.

[0081] The present disclosure (2) is a method for producing a coating film according to the present disclosure (1), in which the step between the conductive metal portion and the underlying layer other than the conductive metal portion is 2000 μm or less.

[0082] The present disclosure (3) is a method for producing a coating film according to the present disclosure (1) or (2), in which the conductive metal portion is formed by a conductive metal member embedded in a substrate.

[0083] The present disclosure (4) is a method for producing a coating film according to any one of the present disclosures (1) to (3), in which the conductive metal is stainless steel.

[0084] The present disclosure (5) is a method for producing a coating film according to any one of the present disclosures (1) to (4), wherein the substrate includes the surface of a sealant filled in the joints of a siding board.

[0085] The present disclosure (6) is a method for producing a coating film according to any one of the present disclosures (1) to (5), wherein the urea resin layer has a wet film thickness of 50 μm or more.

[0086] The present disclosure (7) is a method for producing a coating film according to any one of the present disclosures (1) to (6), in which the dry thickness of the resulting coating film is 50 μm or more.

[0087] The present disclosure (8) is a method for producing a coating film according to any one of the present disclosures (1) to (7), further comprising the step of forming a primer layer on the surface of the base prior to the step of forming the urea resin layer.

[0088] The present disclosure (9) is a film thickness measurement method including a step of forming a coating film by the manufacturing method described in any one of the present disclosures (1) to (8), and a step of measuring the film thickness of the formed coating film with an eddy current film thickness meter or an electromagnetic film thickness meter. [Explanation of symbols]

[0089] 10 Base 20 Conductive metal parts 30 Urea resin layer 40 Film Thickness Gauge 41 Detector head 50 Sealant 60 Conductive metal parts 70 Siding Board

Claims

1. The method includes applying a urea resin coating composition onto a substrate including a substantially smooth conductive metal portion to form a urea resin layer, The conductive metal portion is formed by a conductive metal member embedded in a substrate. Coating manufacturing method.

2. The method includes applying a urea resin coating composition onto a substrate including a substantially smooth conductive metal portion to form a urea resin layer, The substrate includes a surface of a sealant filled into the joints of the siding boards. Coating manufacturing method.

3. The method for producing a coating film according to claim 1 or 2, wherein the step between the conductive metal portion and the underlying layer other than the conductive metal portion is 2000 μm or less.

4. The method for producing a coating film according to claim 1 or 2, wherein the conductive metal is stainless steel.

5. The method for producing a coating film according to claim 1 or 2, wherein the urea resin layer has a wet film thickness of 50 μm or more.

6. The method for producing a coating film according to claim 1 or 2, wherein the dry thickness of the resulting coating film is 50 μm or more.

7. The method for producing a coating film according to claim 1 or 2, further comprising the step of forming a primer layer on the surface of the base prior to the step of forming the urea resin layer.

8. A step of forming a coating film by the manufacturing method according to claim 1 or 2; and measuring the thickness of the formed coating film with an eddy current film thickness meter or an electromagnetic film thickness meter; Film thickness measurement method.

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