Multilayer coating film, exterior wall structure, and method for forming multilayer coating film

Abstract

To provide a formation method of a laminated coating film which suppresses a substrate pattern such as a joint pattern from appearing on a surface.SOLUTION: A formation method of a laminated coating film includes an undercoating film formation step of coating a coating material for undercoating onto a surface of a coated surface of an outer wall, and forming a film, a middle coating film formation step of coating a coating material for middle coating onto a surface of the undercoating film formed by the undercoating film formation step, and forming a film, and a top coating film formation step of coating a coating material for top coating onto a surface of the middle coating film formed by the middle coating film formation step, and forming a film, wherein each of the coating material for undercoating, the coating material for middle coating and the coating material for top coating contains an aggregate, the coating material for middle coating contains more aggregate than the coating material for undercoating and the coating material for top coating, the aggregate for middle coating contains an aggregate having a particle diameter larger than those of the aggregate of the coating material for undercoating and the aggregate of the coating material for top coating.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for forming a multilayer coating film, an intermediate coating material, and an exterior wall structure. [Background technology]

[0002] Wall panels such as ALC (lightweight aerated concrete) and PC (precast concrete) are widely used as building materials for the walls, floors, roofs, etc. of buildings. In such wall panels, the joints between the panels (gaps between multiple adjacent panels) are usually filled with a sealant, and then a finish coat is applied to the entire surface. In some cases, the finish coat is applied multiple times to form a multi-layered coating film.

[0003] However, even after the finish coat is applied, the unevenness of the joints filled with sealant can remain as a joint pattern, which can impair the design. In recent years, there has been a demand for large, flat wall-like designs for exterior walls using wall panels, and there is a strong demand for joint patterns that are less noticeable.

[0004] For this reason, methods of filling the joints in wall panels have been proposed that reduce unevenness in the joints filled with sealant.

[0005] For example, Patent Document 1 describes a joint filling method for wall panels including "a sealant filling step of filling recesses provided along the joints where wall panels are butted together with sealant, a curing step of curing the sealant filled in the recesses for a prescribed period of time, a joint filling material filling step of filling the recesses with joint filling material after the curing step, and a painting step of applying a finishing material to the filled surface with the joint filling material," and states that this "makes it possible to make the joints covered with the finishing material less noticeable."

[0006] On the other hand, plaster-like paints are known that are intended to achieve a calm, relatively flat finish similar to that of plaster.

[0007] For example, Patent Document 2 describes a "plaster-like coating material that contains 40 to 80% by weight of either slaked lime or calcium carbonate or both components in total, and a synthetic resin emulsion with a resin component content of 10% by weight or less." [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2014-145189 A (Claim 1, Effects of the Invention) [Patent Document 2] JP 2013-240749 A (Claim 1) Summary of the Invention [Problem to be solved by the invention]

[0009] The joint filling method described in the above Patent Document 1 can make the joints covered with a finishing material (joint pattern) less noticeable. However, in order to make the joint pattern almost invisible, it was necessary to apply a finishing material containing a large amount of very large aggregate (for example, calcium carbonate with an average particle size of about 1.4 mm). As a result, the finished product tended to have a rough feel.

[0010] On the other hand, if you want to achieve a relatively flat finish with a calm plaster-like finish, you can use a so-called plaster-like paint as a finishing material. However, while you can achieve a plaster-like finish, the joint pattern may still be visible on the surface. This phenomenon is somewhat alleviated when the plaster-like paint is applied multiple times (2 to 3 times) to create a multi-layered coating, but it is still difficult to hide the joint pattern.

[0011] The present invention has been made in consideration of the above-mentioned matters, and has an object to provide a method for forming a multi-layer coating film in which a base pattern such as a joint pattern is less likely to appear on the surface. [Means for solving the problem]

[0012] In order to solve the above problems, the method for forming a multilayer coating film includes an undercoat coating film forming step of applying an undercoat paint to the surface of a surface to be coated such as an exterior wall to form a film, an intermediate coating film forming step of applying an intermediate coating paint to the surface of the undercoat coating film formed by the undercoat coating film forming step to form a film, and a topcoat coating film forming step of applying a topcoat paint to the surface of the intermediate coating film formed by the intermediate coating film forming step to form a film, wherein the undercoat paint, the intermediate coating paint and the topcoat paint each contain aggregate, and the intermediate coating paint contains an equal or greater amount of aggregate than the undercoat paint and the topcoat paint that contain a larger amount of aggregate, or the aggregate of the intermediate coating paint contains aggregate with a particle diameter equal to or greater than the largest particle diameter contained in the undercoat paint and the topcoat paint that contain aggregate with a larger particle diameter.

[0013] This method for forming a multilayer coating film makes it possible to form a multilayer coating film in which the base pattern, such as the joint pattern, is less likely to show on the surface (high base hiding power). In other words, the intermediate coat paint contains an equal or greater amount of aggregate than the paint containing more aggregate among the undercoat paint and the topcoat paint, or the aggregate in the intermediate coat paint contains aggregate with a particle diameter equal to or larger than the largest particle diameter contained in the paint containing aggregate with a larger particle diameter among the undercoat paint and the topcoat paint, thereby increasing the thickness of the layer formed by the intermediate coat paint and enhancing its hiding power, making it difficult for base patterns such as joint patterns to appear on the surface. Here, the method for forming a multilayer coating film can be such that the intermediate coat paint contains more aggregate than the undercoat paint and the topcoat paint, or the aggregate of the intermediate coat paint contains aggregate with a larger particle size than the aggregate of the undercoat paint and the topcoat paint.

[0014] In addition, in order to solve the above problems, the method for forming a multilayer coating film includes an undercoat coating film forming step of applying an undercoat paint to the surface of a surface to be coated such as an exterior wall to form a film, an intermediate coating film forming step of applying an intermediate coating paint to the surface of the undercoat coating film formed by the undercoat coating film forming step to form a film, and a topcoat coating film forming step of applying a topcoat paint to the surface of the intermediate coating film formed by the intermediate coating film forming step to form a film, wherein the undercoat paint, the intermediate coating paint and the topcoat paint each contain aggregate, the intermediate coating paint contains more aggregate than the undercoat paint and the topcoat paint, and the aggregate of the intermediate coating paint contains aggregate with a larger particle diameter than the aggregate of the undercoat paint and the topcoat paint.

[0015] This method for forming a multilayer coating film makes it possible to form a multilayer coating film in which the base pattern, such as the joint pattern, is less likely to show on the surface (high base hiding power). In other words, the intermediate coat paint contains more aggregate than the undercoat paint and the topcoat paint, and the aggregate in the intermediate coat paint contains aggregate with a larger particle size than the aggregate in the undercoat paint and the topcoat paint, so the layer formed by the intermediate coat paint becomes thicker and has higher hiding power, making it even more difficult for base patterns such as joint patterns to show on the surface. In addition, if such an undercoat paint is applied directly to the surface to be painted, it is thought that the weather resistance and adhesion may not be sufficient because a large amount of aggregate is mixed in. However, the undercoat paint strengthens the base hiding power, while the undercoat paint ensures adhesion and weather resistance, and the topcoat paint ensures weather resistance and design, thereby achieving the required characteristics as a multilayer coating film. For this reason, it is preferable that the resins used in the intermediate coating, the undercoat coating and the topcoat coating are the same type of resin. In these methods for forming a multilayer coating film, the undercoat paint, the intermediate coat paint and the top coat paint preferably contain a pigment in addition to an aggregate. As the pigment, for example, a coloring pigment can be used.

[0016] Here, the method for forming a multilayer coating film can be such that the aggregate contained in the undercoat paint, intermediate coat paint and top coat paint is calcium carbonate.

[0017] Calcium carbonate is suitable for forming a plaster-like coating film.

[0018] The top coating paint preferably contains 8 to 17% by weight of a resin component and 45 to 65% by weight of an aggregate, and the method for forming a multi-layer coating film is preferably used.

[0019] This topcoat paint is also suitable for forming a plaster-like coating film.

[0020] It is also preferable to use a method for forming a multilayer coating film in which the undercoat paint contains 6 to 13 weight % of a resin component and 55 to 75 weight % of aggregate, with 2.5 to 7.5 weight % of the aggregate having a particle diameter of 700 μm or more. More specifically, the intermediate coating material preferably contains 6 to 13% by weight of a resin component, 3 to 7% by weight of aggregate having an average particle diameter of 18 to 26 μm, 3 to 7% by weight of aggregate having an average particle diameter of 90 to 130 μm, 30 to 60% by weight of aggregate having an average particle diameter of 250 to 290 μm, and 7 to 13% by weight of aggregate having an average particle diameter of 600 to 800 μm, and a method for forming a multilayer coating film is preferably used.

[0021] This undercoat paint can ensure sufficient film thickness and hiding power, making it even more difficult for base patterns such as joint patterns to show on the surface.

[0022] It is also preferable to use a method for forming a multi-layer coating film in which the undercoat paint and the topcoat paint have the same composition.

[0023] Topcoat paints have a plaster-like appearance and are excellent in design, and also have excellent weather resistance when they contain less aggregate than undercoat paints. They also have high adhesion to the base. Therefore, topcoat paints can be used as undercoat paints, which reduces the total paint cost.

[0024] It is also preferable that the method for forming a laminated coating film is one in which the surface to be coated has a plurality of adjacent panels and joints formed of a sealant filled in the gaps between the adjacent panels.

[0025] A multilayer coating film formed using an undercoat paint, an intermediate coat paint and a topcoat paint is suitable for use on the above-mentioned painted surfaces because it ensures adhesion and weather resistance while preventing the undercoat patterns, such as joint patterns, from appearing on the surface.

[0026] The intermediate coating material used in the above-mentioned method for forming a laminated coating film is preferably one that contains 6 to 13% by weight of a resin component and 55 to 75% by weight of aggregate, with 2.5 to 7.5% by weight of aggregate having a particle diameter of 700 μm or more. More specifically, a mixture containing 6 to 13% by weight of a resin component, 3 to 7% by weight of aggregate having an average particle diameter of 18 to 26 μm, 3 to 7% by weight of aggregate having an average particle diameter of 90 to 130 μm, 30 to 60% by weight of aggregate having an average particle diameter of 250 to 290 μm, and 7 to 13% by weight of aggregate having an average particle diameter of 600 to 800 μm is preferably used.

[0027] The above-mentioned problems are also solved by an exterior wall structure comprising an undercoat coating film formed by applying an undercoat paint to the surface of the surface to be painted of an exterior wall, an intermediate coating film formed by applying an intermediate coating paint to the surface of the undercoat coating film, and a topcoat coating film formed by applying a topcoat paint to the surface of the intermediate coating film, wherein the undercoat paint, the intermediate coating paint and the topcoat paint each contain aggregate, and the intermediate coating paint contains an equal or greater amount of aggregate than a paint containing a larger amount of aggregate among the undercoat paint and the topcoat paint, or the aggregate of the intermediate coating paint contains aggregate having a particle diameter equal to or greater than the largest particle diameter contained in a paint containing aggregate with a larger particle diameter among the undercoat paint and the topcoat paint. In other words, the intermediate coating film contains the same amount of aggregate as or more than the coating film containing more aggregate out of the undercoat coating film and the topcoat coating film, or the aggregate of the intermediate coating film contains aggregate with a particle diameter equal to or larger than the largest particle diameter of aggregate contained in the coating film containing aggregate with a larger particle diameter out of the undercoat coating film and the topcoat coating film. Here, the intermediate coating film may have an exterior wall structure in which the intermediate coating film contains more aggregate than the undercoat coating film and the topcoat coating film, or the aggregate of the intermediate coating film contains aggregate with a larger particle size than the aggregate of the undercoat coating film and the aggregate of the topcoat coating film. It is also preferable for the exterior wall structure to be such that the intermediate coating film contains more aggregate than the undercoat coating film and the topcoat coating film, and the aggregate of the intermediate coating film contains aggregate with a larger particle size than the aggregate of the undercoat coating film and the aggregate of the topcoat coating film. Effect of the Invention

[0028] The present invention can provide a method for forming a multilayer coating film in which a base pattern such as a joint pattern is less likely to appear on the surface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, an embodiment of the present invention will be described by way of example. The method for forming a multilayer coating film includes a base coat film forming step, a middle coat film forming step, and a top coat film forming step. Each step will be described in detail below, but the present invention is not limited to the following embodiment. In this specification, the "average particle size" refers to the 50% diameter of the weight cumulative particle size distribution, and the particle size distribution was measured using a laser diffraction particle size distribution measuring device (HRA Microtrack, manufactured by Nikkiso Co., Ltd.).

[0030] [Undercoat coating process] The undercoat coating film forming process is a process in which an undercoat paint is applied to the surface of a surface to be painted, such as an exterior wall, to form a film.

[0031] The surface to be coated with the undercoat paint is not particularly limited, but is preferably a surface having wall panels such as ALC, with the joints between the panels filled with a sealant, etc. The laminated coating film of the present invention can make the joint patterns between the wall panels less noticeable.

[0032] 1. Pigments The undercoat paint preferably contains a pigment. Examples of pigments that can be used include, but are not limited to, titanium oxide, yellow iron oxide, red iron oxide (ferric oxide: red iron oxide), phthalocyanine blue, ocher, ultramarine blue, and carbon black. In the case of a white plaster-like undercoat paint, titanium oxide is often used as a white pigment.

[0033] 2. Aggregate The undercoat paint also contains aggregate. Examples of aggregate include, but are not limited to, kansui stone, silica sand, calcium carbonate, etc. Among them, it is preferable to use calcium carbonate as the aggregate. The undercoat paint preferably contains 45 to 65% by weight of aggregate, more preferably 50 to 60% by weight of aggregate, and most preferably 52 to 56% by weight of aggregate.

[0034] Regarding the aggregate contained in the undercoat paint, for example, aggregate having an average particle diameter of 18 to 26 μm, aggregate having an average particle diameter of 90 to 130 μm, aggregate having an average particle diameter of 250 to 290 μm, and aggregate having an average particle diameter of 350 to 450 μm can be used alone or in appropriate combination. More specifically, 4.5 to 9.0% by weight of aggregate having an average particle diameter of 18 to 26 μm, 20 to 45% by weight of aggregate having an average particle diameter of 90 to 130 μm, 4.5 to 9.0% by weight of aggregate having an average particle diameter of 250 to 290 μm, and 4.5 to 9.0% by weight of aggregate having an average particle diameter of 350 to 450 μm can be used.

[0035] As described below, it is preferable that part of the aggregate in the intermediate coating contains aggregate having a particle size larger than that of the aggregate in the undercoat coating.

[0036] 3. Resin component The resin component of the undercoat paint is not particularly limited. For example, known synthetic resins such as acrylic resin, ethylene-acrylic resin, vinyl acetate-acrylic resin, styrene-acrylic resin, urethane resin, silicone resin, urethane-acrylic resin, and silicone-acrylic resin can be used. Among them, it is preferable to use an acrylic silicone resin from the viewpoint of weather resistance. For example, an acrylic silicone resin or a ceramic modified acrylic silicone resin is preferable.

[0037] The resin component of the undercoat paint is preferably used in the form of a synthetic resin emulsion in which resin is polymerized in water in the form of fine particles. An example of an acrylic silicone resin emulsion is "Polydurex G-624" manufactured by Asahi Kasei Corporation. The undercoat paint preferably contains 8 to 17% by weight of a resin component (solid content), and more preferably contains 10 to 15% by weight of a resin component.

[0038] The undercoat paint and the topcoat paint described later may have the same composition, that is, the topcoat paint described later may be used as the undercoat paint.

[0039] 4. Application method, etc. The method of applying the undercoat paint to the surface of the surface to be painted is not particularly limited. For example, it can be applied by spray painting or roller painting. After applying the undercoat paint, it is preferable to use a trowel or the like to smooth the surface before the paint dries. After applying the undercoat paint, it is dried to form a film. After forming the film, it is preferable to provide a curing period of about one day. The next step, the undercoat film forming step, will now be described.

[0040] [Middle coat coating process] The intermediate coating film forming process is a process of applying an intermediate coating paint to the surface of the undercoat coating film formed in the undercoat coating film forming process. In the intermediate coating film forming process, it is preferable to apply an intermediate coating paint that contains a relatively large amount of aggregate and has a large particle size. This makes it difficult for the undercoat pattern, such as the joint pattern, to appear on the surface.

[0041] 1. Pigments The intermediate coating preferably contains a pigment. The pigment is not particularly limited, as in the undercoat coating. When a white intermediate coating is used, titanium oxide is often used as a white pigment.

[0042] 2. Aggregate The intermediate coating material also contains an aggregate, which, like the undercoat coating material, is not particularly limited, but is preferably calcium carbonate.

[0043] The intermediate coating paint preferably contains more aggregate than the undercoat coating paint described above or the topcoat coating paint described below. Under these conditions, the intermediate coating paint preferably contains 55 to 75% by weight of aggregate, more preferably 60 to 70% by weight of aggregate, and most preferably 62 to 68% by weight of aggregate.

[0044] Furthermore, the intermediate coating paint preferably contains aggregates with a larger particle size than the undercoat coating paint described above and the topcoat coating paint described below. It is preferable that aggregates with a large particle size of 700 μm or more account for 2.5 to 7.5% by weight of the intermediate coating paint. More specifically, the intermediate coating material preferably contains 3 to 7% by weight of aggregate having an average particle diameter of 18 to 26 μm, 3 to 7% by weight of aggregate having an average particle diameter of 90 to 130 μm, 30 to 60% by weight of aggregate having an average particle diameter of 250 to 290 μm, and 7 to 13% by weight of aggregate having an average particle diameter of 600 to 800 μm.

[0045] In addition, the intermediate coating material may be divided into a base coating material and an aggregate mixed on site, and some or all of the aggregate may be mixed just before the work. For example, some or all of the aggregate with an average particle size of 600 to 800 μm and the aggregate with an average particle size of 250 to 290 μm may be mixed just before the work.

[0046] 3. Resin component The resin component of the intermediate coating is not particularly limited, but, like the undercoat coating, it is preferable to use an acrylic silicone resin from the viewpoint of weather resistance. Acrylic silicone resin and ceramic modified acrylic silicone resin are suitable.

[0047] 4. Application method, etc. The resin component of the intermediate coating material is preferably used in the form of a synthetic resin emulsion, similar to the undercoat coating material. The undercoat paint preferably contains 6 to 13% by weight of the resin component, more preferably contains 7 to 12% by weight of the resin component, and most preferably contains 8 to 11% by weight of the resin component.

[0048] The method of applying the intermediate coating paint to the surface of the undercoat coating film formed in the undercoat coating film forming process is not particularly limited. For example, it can be applied by spray coating or roller coating. After applying the intermediate coating paint, the surface can be pressed smoothly using a trowel or the like before the paint dries. After applying the intermediate coating paint, it is dried to form a film. After forming the film, it is preferable to provide a curing period of about two days. The next step, the topcoat film forming step, will now be described.

[0049] [Topcoat coating process] The topcoat coating film forming step is a step of applying a topcoat paint to the surface of the intermediate coating film formed in the intermediate coating film forming step to form a film.

[0050] 1. Pigments The topcoat paint preferably contains a pigment. The pigment is not particularly limited, as in the undercoat paint and the intermediate coat paint. When making a topcoat paint with a white plaster finish, titanium oxide is often used as a white pigment.

[0051] 2. Aggregate The topcoat paint also contains an aggregate. The aggregate is not particularly limited, as in the undercoat paint and the intermediate coat paint, but it is preferable to use calcium carbonate in order to form a plaster-like coating film. The top coat paint preferably contains 45 to 65% by weight of aggregate, more preferably 50 to 60% by weight of aggregate, and most preferably 52 to 56% by weight of aggregate.

[0052] 3. Resin component The resin component of the topcoat paint is not particularly limited, but, like the undercoat paint and the intermediate coat paint, it is preferable to use an acrylic silicone resin from the viewpoint of weather resistance. Acrylic silicone resin and ceramic modified acrylic silicone resin are suitable.

[0053] The resin component of the topcoat paint is preferably used in the form of a synthetic resin emulsion, similar to the undercoat paint and the intermediate coat paint. The topcoat paint preferably contains 8 to 17% by weight of the resin component, and more preferably contains 10 to 15% by weight of the resin component.

[0054] As mentioned above, the top coat paint and the undercoat paint can have the same composition, i.e., the top coat paint can be used as the undercoat paint.

[0055] 4. Application method, etc. The method of applying the topcoat paint to the surface of the intermediate coating film formed in the intermediate coating film forming step is not particularly limited. For example, it can be applied by spray coating or roller coating. After applying the topcoat paint, it is preferable to press the surface smoothly using a trowel or the like before the paint dries. After applying the topcoat paint, it is dried to form a film.

[0056] Through the undercoat coating film forming step, the middle coat coating film forming step, and the top coat coating film forming step, a multilayer coating film is formed on the surface of the surface to be painted, such as an exterior wall. EXAMPLES

[0057] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these. In the examples, the ratios and the like are based on weight.

[0058] 1. Preparation of top coat paint, undercoat paint and undercoat paint Topcoat paint, undercoat paint, and undercoat paint were prepared based on the formulation in Table 1 below. For all paints, an acrylic silicone resin emulsion ("Polydurex G-624" manufactured by Asahi Kasei Corporation) was used as the emulsion resin, and calcium carbonate was used as the aggregate.

[0059] Regarding the aggregates, specifically, for the topcoat paint and undercoat paint, calcium carbonate with an average particle size of 22 μm (Whiten H, manufactured by Toyo Fine Chemical Co., Ltd.), calcium carbonate with an average particle size of 110 μm (coarse calcium carbonate, manufactured by Sankyo Seiko Co., Ltd.), calcium carbonate with an average particle size of 270 μm (granular calcium carbonate K1, manufactured by Sankyo Seiko Co., Ltd.), and calcium carbonate with an average particle size of 400 μm (granular calcium carbonate K2, manufactured by Sankyo Seiko Co., Ltd.) were used. On the other hand, for the undercoat paint, calcium carbonate with an average particle size of 22 μm (Whiten H, manufactured by Toyo Fine Chemical Co., Ltd.), calcium carbonate with an average particle size of 110 μm (coarse calcium carbonate, manufactured by Sankyo Seiko Co., Ltd.), calcium carbonate with an average particle size of 270 μm (granular calcium carbonate K1, manufactured by Sankyo Seiko Co., Ltd.), and calcium carbonate with an average particle size of 700 μm (granular calcium carbonate K3, manufactured by Sankyo Seiko Co., Ltd.) were used. Calcium carbonate with an average particle size of 700 μm was mixed at 10% by weight, and calcium carbonate with a particle size of 700 μm or more was approximately 5% by weight.

[0060] In this example, as shown in Table 1, the undercoat paint and the topcoat paint had the same composition.

[0061] In this embodiment, the undercoat paint was divided into a base paint and on-site mixed aggregate, with all of the aggregate with an average particle diameter of 700 μm and approximately 90% of the aggregate with an average particle diameter of 270 μm being on-site mixed aggregate, which was mixed into the base paint immediately before work (a portion (the remainder) of the aggregate with an average particle diameter of 270 μm was mixed into the base paint in advance).

[0062] [Table 1]

[0063] 2. Preparation of the surface to be painted ALC panels were installed on the exterior walls of the building, and the joints were filled with sealant and cured, after which the joints were filled with joint filler and smoothed out with a spatula.Then, the surface was cured for several days to prepare the painting surface.

[0064] 3. Formation of multilayer coating The undercoat paint (with the same composition as the topcoat paint) was sprayed onto the surface to be painted using a stucco gun (diameter 8 mm). The amount of paint applied was approximately 1.5 kg / m 2 After painting, before the paint dried, the surface was pressed flat with a stainless steel trowel. After that, it was dried to form a film, and a curing period of about one day was set to obtain a primer coating.

[0065] Next, the intermediate coating was sprayed onto the surface of the undercoat film using a tile gun (diameter 6.5 mm). The coating amount was approximately 1.5 kg / m 2 After painting, before the paint dried, the surface was pressed flat with a stainless steel trowel. After that, it was dried to form a film, and a curing period of about two days was set to obtain the intermediate coating film.

[0066] Finally, the topcoat paint was sprayed onto the surface of the intermediate coating film using a stucco gun (diameter 8 mm). The coating amount was approximately 1.5 kg / m 2After painting, the surface was smoothed with a trowel before the paint dried. It was then dried to form a film, resulting in a multilayered coating consisting of an undercoat coating, an intermediate coating, and a topcoat coating.

[0067] The laminated coating films of the above examples were evaluated for design, base hiding power, and weather resistance. Design and base hiding power were evaluated by visual inspection by 5 to 10 people from a distance of 3 to 5 m from the painted object after painting.

[0068] Specifically, cases where 80% or more of the evaluators judged it to be good were rated as ○, cases where 50% to less than 80% judged it to be good were rated as △, cases where 20% to less than 50% judged it to be good were rated as △ to ×, and cases where less than 20% judged it to be good were rated as ×.

[0069] Regarding weather resistance, the color difference (ΔE) after 2500 hours of exposure to a xenon weather meter based on JIS K5600-7-7 was evaluated as follows: ΔE≦3 was rated as ○, 3<ΔE≦5 was △, and 5<ΔE was ×.

[0070] [Table 2]

[0071] Example 1 provided very good results in terms of design, base hiding ability, and weather resistance.

[0072] Comparative Example 1 is an example in which, in Example 1, no intermediate coating was applied (only the undercoat coating and topcoat coating were applied), and the result was poor in base hiding power.

[0073] Comparative Example 2 is an example in which the intermediate coating film in Example 1 was formed using a topcoat paint, and the result was poor in base hiding power.

[0074] Comparative Example 3 is an example in which no topcoat paint was applied in Example 1, and the results were inferior in design and weather resistance.

[0075] The present invention has been described above with reference to specific embodiments and examples, but the present invention is not limited to the above-mentioned embodiments, and various changes and modifications can be made by those skilled in the art without departing from the scope of the claims attached to the application of this application.

Claims

1. A primer coating film formed by applying a primer paint to the surface of the surface to be painted, such as an exterior wall, and A middle coat coating film formed by applying a middle coat paint to the surface of the undercoat coating film; and a topcoat coating film formed by applying a topcoat paint to the surface of the intermediate coating film. the intermediate coating paint contains more aggregate than the undercoat coating paint and the topcoat coating paint, whichever of the two contains more aggregate, and the aggregate of the intermediate coating paint contains aggregate with a particle size larger than that of the aggregate of the undercoat coating paint and the aggregate of the topcoat coating paint; The undercoat paint is The undercoat paint contains 45 to 65% by weight of aggregate in 100% by weight of the undercoat paint, The undercoat paint is In 100% by weight of the undercoat paint, 4.5 to 9.0% by weight of aggregate with an average particle size of 18 to 26 μm, 20 to 45% by weight of aggregate having an average particle size of 90 to 130 μm; The intermediate coating paint is The intermediate coating material contains 55 to 75% by weight of aggregate in 100% by weight of the intermediate coating material, Among the aggregates contained in the undercoat paint, those having a particle size of 700 μm or more account for 2.5 to 7.5% by weight, The topcoat paint is The topcoat paint contains 45 to 65% by weight of aggregate in 100% by weight of the topcoat paint. Multilayer coating.

2. The topcoat paint and the undercoat paint have the same composition, The topcoat paint is In 100% by weight of the topcoat paint, 4.5 to 9.0% by weight of aggregate with an average particle size of 18 to 26 μm, 20 to 45% by weight of aggregate having an average particle size of 90 to 130 μm; The multilayer coating film according to claim 1.

3. The undercoat paint is In 100% by weight of the undercoat paint, 4.5 to 9.0% by weight of aggregate with an average particle size of 18 to 26 μm, 20 to 45% by weight of aggregate with an average particle size of 90 to 130 μm, 4.5 to 9.0% by weight of aggregate with an average particle size of 250 to 290 μm, and 4.5 to 9.0% by weight of aggregate having an average particle size of 350 to 450 μm. The multilayer coating film according to claim 1.

4. The undercoat paint is In 100% by weight of the undercoat paint, 4.5 to 9.0% by weight of aggregate with an average particle size of 18 to 26 μm, 20 to 45% by weight of aggregate with an average particle size of 90 to 130 μm, 4.5 to 9.0% by weight of aggregate with an average particle size of 250 to 290 μm, 4.5 to 9.0% by weight of aggregate having an average particle size of 350 to 450 μm; The topcoat paint is In 100% by weight of the topcoat paint, 4.5 to 9.0% by weight of aggregate with an average particle size of 18 to 26 μm, 20 to 45% by weight of aggregate with an average particle size of 90 to 130 μm, 4.5 to 9.0% by weight of aggregate with an average particle size of 250 to 290 μm, and 4.5 to 9.0% by weight of aggregate having an average particle size of 350 to 450 μm. The multilayer coating film according to claim 2.

5. The undercoat paint is In 100% by weight of the undercoat paint, The emulsion resin contains 8 to 17% by weight of a resin component, which is the solid content of the emulsion resin. The intermediate coating paint is In 100% by weight of the undercoat paint, The emulsion resin contains 6 to 13% by weight of a resin component, which is the solid content of the emulsion resin. The topcoat paint is In 100% by weight of the topcoat paint, Contains 8 to 17% by weight of a resin component which is the solid content of the emulsion resin; The multilayer coating film according to any one of claims 1 to 4.

6. The intermediate coating paint is In 100% by weight of the undercoat paint, 3 to 7% by weight of aggregate with an average particle size of 18 to 26 μm, 3 to 7% by weight of aggregate with an average particle size of 90 to 130 μm, 30 to 60% by weight of aggregate with an average particle size of 250 to 290 μm, and 7 to 13% by weight of aggregate having an average particle size of 600 to 800 μm. The multilayer coating film according to any one of claims 1 to 5.

7. The aggregate contained in the undercoat paint, the intermediate coat paint and the top coat paint is calcium carbonate, granite or silica sand. The laminated coating film according to any one of claims 1 to 6.

8. The surface to be painted is Adjacent panels and and a joint portion made of a sealant filled in the gaps between the adjacent panels. An exterior wall structure provided with the laminated coating film according to any one of claims 1 to 7.

9. A primer coating film forming process in which a primer paint is applied to the surface of a surface to be painted, such as an exterior wall, to form a film; A middle coat coating film forming process is performed by applying a middle coat paint to the surface of the undercoat coating film formed by the undercoat coating film forming process to form a film; and a topcoat coating film forming process for applying a topcoat paint to the surface of the intermediate coating film formed by the intermediate coating film forming process to form a film. the intermediate coating paint contains more aggregate than the undercoat coating paint and the topcoat coating paint, whichever of the two contains more aggregate, and the aggregate of the intermediate coating paint contains aggregate with a particle size larger than that of the aggregate of the undercoat coating paint and the aggregate of the topcoat coating paint; The undercoat paint is The undercoat paint contains 45 to 65% by weight of aggregate in 100% by weight of the undercoat paint, The undercoat paint is In 100% by weight of the undercoat paint, 4.5 to 9.0% by weight of aggregate with an average particle size of 18 to 26 μm, 20 to 45% by weight of aggregate having an average particle size of 90 to 130 μm; The intermediate coating paint is The intermediate coating material contains 55 to 75% by weight of aggregate in 100% by weight of the intermediate coating material, Among the aggregates contained in the undercoat paint, those having a particle size of 700 μm or more account for 2.5 to 7.5% by weight, The topcoat paint is The topcoat paint contains 45 to 65% by weight of aggregate in 100% by weight of the topcoat paint. A method for forming a multilayer coating film.

10. The topcoat paint is In 100% by weight of the topcoat paint, 4.5 to 9.0% by weight of aggregate with an average particle size of 18 to 26 μm, 20 to 45% by weight of aggregate having an average particle size of 90 to 130 μm; The topcoat paint and the undercoat paint have the same composition; The method for forming a multilayer coating film according to claim 9.

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