JP7466913B2 - Coating method for forming a pigment-containing film - Google Patents

Description

The present invention relates to a coating method for forming a pigment-containing film that can be expected to have a coloring effect and a heat-shielding effect, as if it were painted on the surface of a substrate.

Patent Document 1 discloses a colored coating material consisting of 5 to 80% by weight of a coloring material, 0.01 to 30% by weight of an additive, and the remainder being a resin, the coloring material containing a dye and a pigment having a particle size of 0.05 to 10 μm, the weight ratio of the dye to the pigment being 1:99 to 30:70, the additives containing one or more leveling agents selected from the group consisting of a fluorine-based leveling agent, a silicone-based leveling agent, a polymeric ether-based leveling agent, and a nonionic leveling agent, and one or more dispersants selected from the group consisting of a carboxylic acid-based surfactant, a nonionic surfactant, a hydrocarbon-based surfactant, a cationic surfactant, an alkyl phosphate ester, a polyethylene glycol derivative, and a polyester-based polymer compound having an amino functional group in the molecule, and the resin containing one or more resins selected from the group consisting of an acrylic resin, a urethane resin, an epoxy resin, a silicone resin, a vinyl resin, a melamine resin, and a polyester resin. The colored coating material is then sprayed onto the substrate and dried at 120°C for 30 minutes to form a coating film of approximately 10 μm.

Patent Document 2 discloses a heat-shielding film having a thermoplastic resin layer made of a thermoplastic acrylic resin containing cesium tungsten oxide and having a glass transition temperature of 40 to 120°C on at least one surface of a transparent resin film, and a heat-shielding laminated glass having a configuration in which the heat-shielding film is sandwiched between two glass plates, the heat-shielding film being characterized in that at least one surface of the transparent resin film has a thermoplastic resin layer made of a thermoplastic acrylic resin containing cesium tungsten oxide and having a glass transition temperature of 40 to 120°C.

JP 2001-254054 A JP 2017-185669 A

The colored coating material in Patent Document 1 is a technology in which the material is sprayed onto a substrate and dried at 120°C for 30 minutes to form a coating film of about 10 μm, but this requires a drying device, which creates the problem that the coating film cannot be formed easily.

When spraying paint indoors with an air gun, the paint can get splattered over a wide area, which can pose a problem if you have to move furniture and other items already installed indoors, or if you have to protect a wide area of walls, floors, etc.

In the case of one-room apartment complexes and other collective buildings, there was a problem in that it was difficult to ventilate and exhaust the mist generated by spray painting throughout the entire building.

In addition, when spraying paint outdoors with an air gun, a compressor is required to generate air pressure, and a shatterproof net is required to prevent the mist from scattering onto surrounding buildings. This poses the problem of extensive preparations, such as the need to set up scaffolding to install the shatterproof net, especially when spraying onto window glass on high floors of a building.

The heat-shielding laminated glass in Patent Document 2 is a heat-shielding laminated glass that has a heat-shielding film sandwiched between two glass sheets, so there is no problem when installing it in a newly constructed building, but when installing it in an existing building, there is a problem in that the existing glass must be replaced.

Even when applying heat-shielding film to existing glass, there is a problem in that sufficient adhesion cannot be achieved unless the oily film adhering to the glass is removed, necessitating polishing work. Furthermore, when applying heat-shielding film to glass indoors, it is difficult to remove air bubbles, and furthermore, dust and dirt floating in the air can get in between the glass and the film, significantly damaging the aesthetic appearance of the transparent glass. Furthermore, when applying heat-shielding film outdoors, there is a problem in that the heat-shielding performance rapidly deteriorates in a short period of time because it is exposed to the harsh outdoor environment.

The present invention was conceived in light of these problems, and aims to provide a coating method for forming a pigment-containing film using a pigment that can be expected to provide a coloring effect and a heat-shielding effect on a substrate without the need for large-scale equipment, as it does not require drying equipment, compressors, or air guns and does not scatter into the surrounding area.

In the present invention, fixation means making the pigment immobile. Also, fixation component means a component that fixes the pigment.

The pigment-containing film forming coating method according to claim 1 includes a pigment-containing film forming step in which a coating composition containing a moisture-curable fixing component, a pigment, and a solvent is applied to a surface of a substrate, or while the coating composition is being applied, the coating composition is rubbed with a buff against the surface of the substrate to which the coating composition has been applied, and the coating composition is spread by buffing, thereby mixing the moisture contained in the air with the coating composition, thereby accelerating a curing reaction of the coating composition on the substrate surface and fixing the pigment to the substrate surface , and the solvent is characterized in that a volatile solvent having high compatibility with the pigment-containing film formed in the pigment-containing film forming step is combined with a non-volatile solvent having low compatibility with the pigment-containing film .

The coating method for forming a pigment-containing film according to claim 2 is characterized in that, in claim 1 , the moisture-curable immobilizing component contained in the coating composition comprises a moisture-curable silicone and a reaction catalyst.

The coating method for forming a pigment-containing film according to claim 3 comprises the steps of:
The moisture-curable silicone is represented by the following general formula (1):
(wherein n is an integer of 1 to 10, and X is independently a halogen atom, a hydrogen atom, methoxy, ethoxy, propoxy, isopropoxy, acetoxy, enoxy, oxime, methyl, ethyl, propyl, isopropyl, normal hexyl, cyclohexyl, normal octyl, normal decyl, phenyl, vinyl, allyl, parastyl, 3-glycidoxypropyl, 2-(3,4-epoxycyclohexylethyl, 3-aminopropyl, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyl, N-phenyl-3-aminoethyl-3-aminopropyl, 3-methacryloxypropyl, 3-acryloxypropyl, 3-mercaptopropyl, 3-ureidopropyl, 3-isocyanatopropyl, isocyanurate, or an acid anhydride).

The coating method for forming a pigment-containing film according to claim 4 is characterized in that, in any one of claims 1 to 3 , an undercoat application step is provided in which an undercoat is applied to the surface of the substrate before the application of the coating composition.

The coating method for forming a pigment-containing film according to claim 5 is any one of claims 1 to 4 , further comprising a topcoat application step of applying a topcoat to the surface of the formed pigment-containing film.

The pigment-containing film forming coating method described in claim 1 has the effect of being able to uniformly diffuse pigments having a primary particle size of 5 nm to 100 μm onto the surface of a substrate, and being able to form and fix a pigment-containing film layer onto the substrate surface by operating a polisher equipped with a buff. Even if the pigment-containing film layer is touched with a finger immediately after pressing and spreading with the buff is completed, the pigment does not adhere to the layer. Therefore, it has the remarkable effect of eliminating the need for a drying process to fix the pigment after the buff (polisher) operation.

In addition, pigments with small primary particle diameters can form semi-transparent coatings, which has the effect of ensuring the semi-transparency of the pigment color on substrates that require transparency, such as window glass. Semi-transparency can also be ensured when the film thickness is thin, and by applying multiple coats of coating, the material can be concealed by covering it with the pigment.

In addition, forming a pigment-containing coating on the surface of a substrate generally requires painting work, which requires a dust-free work space, painting equipment, and heating equipment, and also requires high electricity costs. However, the pigment-containing coating method of the present invention can form a pigment-containing coating at room temperature in a place without heating equipment and in a general work environment rather than a clean room, and has the advantage of requiring almost no electricity costs.

In addition, because work can be done in a non-vacuum, clean room working environment, dust in the air will adhere to the surface of the substrate. However, in this case, the thickness of the pigment-containing coating formed is thin, so dust that is visible to the naked eye or whose presence can be seen by light reflection will not adhere, and only dust that is difficult to see with the naked eye will adhere. This dust that is difficult to see with the naked eye has almost no effect on the quality of the coating.

When carrying out the pigment-containing film forming coating method, the pigment and other substances do not scatter into the surrounding area, so there is no need to move furniture and other objects already installed indoors, there is no need to protect walls and floors, and the method can be carried out using a power source of around 100V, which is commonly used in homes.

Even when the pigment-containing film-forming coating method is carried out in a one-room apartment building or other collective building, no mist is generated, so there is no need for ventilation or exhaust throughout the building.

In addition, when the pigment-containing film-forming coating method is carried out outdoors, there is an advantage that a compressor or a mist-scattering prevention net is not required, as compared to when spraying paint with an air gun. In particular, when the pigment-containing film-forming coating method is applied to window glass on a high floor of a building, there is an advantage that there is no need to set up scaffolding to install a mist-scattering prevention net, as compared to when spraying paint with an air gun, and the method can be carried out by suspending a gondola from the roof and loading a small generator (weight 13 kg or less, power consumption 0.9 kW) on the gondola.

In addition, the moisture-curable fixing component, which is made of moisture-curable silicone and a reaction catalyst and is contained in the coating composition, has the effect of fixing the pigment having a primary particle size of 5 nm to 100 μm to the surface of the substrate after the pigment is adhered to the surface of the substrate and preventing the pigment from peeling off. In other words, since the moisture-curable fixing component cures while containing the pigment and also has adhesive properties, the pigment is solidified by the solidified moisture-curable fixing component, which has the remarkable effect of fixing the pigment without the need for a drying process.

The coating method for forming a pigment-containing film according to claim 1 allows the coating material to be spread smoothly and uniformly when rubbed with a buff using a volatile solvent that is highly compatible with the pigment-containing film.

The volatile solvent then evaporates, leaving the non-volatile solvent in liquid form. Since the moisture-curing fixing component is a solid, a layer of the moisture-curing fixing component, which is a solid containing a pigment, is fixed on the surface of the substrate, and the liquid non-volatile solvent becomes the upper layer of the moisture-curing fixing component layer, forming a pigment-containing coating. Therefore, a layer of non-volatile solvent that does not contain a pigment is formed on the surface, and the layer of moisture-curing fixing component containing a pigment is covered with the layer of non-volatile solvent, so that the layer of non-volatile solvent reduces friction between the buff and the pigment-containing coating, and therefore no scratches are formed on the layer of moisture-curing fixing component containing a pigment that has been formed. At this time, the pigment does not move and remains fixed.

The coating method for forming a pigment-containing coating according to claim 2 or 3 has the effect that, since the moisture-curable silicone is easily cured by moisture in the air, the coating composition can be fixed to the substrate or the underlying pigment-containing coating by the buffing operation of pressing the coating composition against the substrate or the underlying pigment-containing coating.

The coating method for forming a pigment-containing film according to the fourth aspect of the present invention has the effect of improving adhesion between the substrate and the pigment by applying an undercoat to the surface of the substrate.

The coating method for forming a pigment-containing film as set forth in claim 5 has the effect of making it difficult for the coloring to fade or change color over a long period of time, and of making it possible to maintain the heat-shielding effect over a long period of time.

FIG. 1 is a diagram showing a process flow of a coating method for forming a pigment-containing film of the present invention. FIG. 2 is a diagram showing a flow chart of a process for forming a two-layer pigmented coating. FIG. 1 is a diagram showing a state in which a rotary polisher is used after a coating composition is applied to a substrate. FIG. 13 is a diagram showing the state when a rotary polisher is used after the coating composition is applied to the buffed surface. FIG. 2 is an explanatory diagram illustrating a state in which two layers of a pigment-containing coating are formed on the surface of a substrate. FIG. 1 is an explanatory diagram illustrating the formation of a first layer of a pigment-containing coating on the surface of a substrate, where (a) is an explanatory diagram of the state after the coating composition has been applied to the substrate, and (b) is an explanatory diagram of the state after pressing with a buff. FIG. 7 is an enlarged view of part A in FIG. FIG. 1 is an explanatory diagram illustrating the formation of a second layer of a pigment-containing coating on a first layer of a substrate, where (a) is an explanatory diagram of the state after the coating composition has been applied on the first layer, and (b) is an explanatory diagram of the state after pressing with a buff. FIG. 11 is an explanatory diagram of a comparative example in which a coating film is formed on the surface of a substrate with a brush. 1A and 1B are explanatory diagrams showing examples of types of buffs of a polisher, in which FIG. 1A shows a case where the buff shape is disk-shaped, and FIG. 1B shows a case where the buff shape is cone-shaped.

The pigment-containing film forming coating method 1 of the present invention is a method for forming a pigment-containing film 50 containing a pigment 9 on the surface of a substrate 8, as shown in FIG. 5, for example, as a pigment-containing film 50 having a two-layer structure of pigment-containing films 51 and 52, and has the distinct effect of spreading and fixing the coating composition 7 almost simultaneously by rotating and pressing a single buff 6. This makes it possible to form a pigment-containing film 50 containing a pigment 9 on the surface of a substrate 8 in a typical indoor or outdoor work space at room temperature.

Therefore, the fact that a separate drying step is not required to fix the paint after buffing 6 is a major difference from the conventional coating method, which involves a drying step to fix the paint after application. Typical drying steps include, for example, drying in a clean room or heating equipment, such as in a dedicated coating factory, and natural drying, but the present invention does not require a drying step to fix the paint after spreading the coating composition 7.

The pigment-containing film forming coating method 1 of the present invention includes a pigment-containing film forming step 3. As shown in FIG. 1, it may include an undercoat application step 2, a pigment-containing film forming step 3, and a topcoat application step 4. It may also be a combination of the undercoat application step 2 and the pigment-containing film forming step 3, or a combination of the pigment-containing film forming step 3 and the topcoat application step 4.

The pigment-containing film forming coating method 1 of the present invention includes a pigment-containing film forming step 3 in which a coating composition 7 containing a moisture-curable fixing component 30, a pigment 9, and a solvent 35 is applied to the surface of a substrate 8, or while the coating composition 7 is being applied, the coating composition 7 is rubbed with a buff 6 against the surface of the substrate 8 to which the coating composition 7 has been applied, and the coating composition 7 is spread by the buff 6, whereby the moisture contained in the air and the coating composition 7 are mixed, accelerating the curing reaction of the coating composition 7 on the surface of the substrate 8, and the pigment 9 is fixed to the surface of the substrate 8. The moisture-curable fixing component 30 is composed of a moisture-curable silicone 31 and a reaction catalyst 32. The moisture-curable fixing component 30 and the solvent 3 are colorless.

The substrate 8 may be made of any material, such as metal, resin, or glass, on whose surface a pigment-containing coating 50 can be formed. The surface may be flat or curved, and may be painted or plated, rather than being limited to the surface of the material.

The substrate 8 may be, for example, parts of buildings (e.g., window glass, roofs, doors, fences, gates, etc.), parts of automobiles (e.g., painted parts of rearview mirrors, door handles, front fenders, bonnets, various doors, rear fenders, etc.), flat or curved glass, metal, or resin parts of decorative items, flat or curved glass, metal, or resin parts of everyday items, or flat or curved parts made of glass, metal, or resin.

The coating composition 7 contains 1% by weight to 90% by weight of the moisture-curable fixing component 30, 1% by weight to 50% by weight of the pigment 9, and as the solvent 35, 1% by weight to 30% by weight of a volatile solvent 35a such as a petroleum-based solvent or an alcohol-based solvent, and 1% by weight to 50% by weight of a non-volatile solvent 35b such as glycol ethers. When the moisture-curable fixing component 30 is taken as 100% by weight, the moisture-curable fixing component 30 contains 50% by weight to 99.9% by weight of the moisture-curable silicone 31 and 0.1% by weight to 50% by weight of the reaction catalyst 32.

The moisture-curable silicone 31 is represented by the following general formula (1):
(wherein n is an integer of 1 to 10, and X is independently a halogen atom, a hydrogen atom, methoxy, ethoxy, propoxy, isopropoxy, acetoxy, enoxy, oxime, methyl, ethyl, propyl, isopropyl, normal hexyl, cyclohexyl, normal octyl, normal decyl, phenyl, vinyl, allyl, parastyl, 3-glycidoxypropyl, 2-(3,4-epoxycyclohexylethyl, 3-aminopropyl, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyl, N-phenyl-3-aminoethyl-3-aminopropyl, 3-methacryloxypropyl, 3-acryloxypropyl, 3-mercaptopropyl, 3-ureidopropyl, 3-isocyanatopropyl, isocyanurate, or an acid anhydride) is a silicone compound having a chemical structure represented by the formula. This allows the pigment-containing coating 50 to react with moisture in the air and quickly cure.

The reaction catalyst 32 may be an acid, an alkali, or an organometallic compound. The reaction catalyst 32 reacts with the moisture-curable silicone 31 when it comes into contact with moisture in the air, causing the moisture-curable silicone 31 to cure quickly.

Next, the pigment 9 will be described. The pigment 9 may be a pigment consisting of only a color pigment, a pigment in which a color pigment is mixed with a heat-shielding pigment, or a pigment consisting of only a heat-shielding pigment. Whether a coloring effect or a heat-shielding effect is expected, for example, when the substrate 8 is a painted part of a rearview mirror or a window of an automobile, the substrate 8, that is, the rearview mirror or window, can be attached to the automobile without being removed, and the pigment-containing film forming coating method 1 of the present invention can be carried out.

Examples of the color pigments 9 include yellow pigments such as yellow lead, isoindolinone, azomethine, anthraquinone, xanthene, etc., black pigments such as carbon black, red pigments such as red lead, iron oxide red, quinacridone, anthraquinone, indigoid, etc., white pigments such as titanium dioxide, zinc oxide, lead color, lithobon, etc., blue pigments such as ultramarine blue, Prussian blue, phthalocyanine, etc., orange pigments such as perinone, diketopyrrolopyrrole, etc., green pigments such as azomethine, phthalocyanine, etc., and purple pigments such as dioxazine. Color pigments also include luster pigments such as pearl pigments, phosphorescent pigments, and fluorescent pigments.

When the content of the color pigment 9 in the coating composition 7 is high, the color pigment coating becomes an opaque coating, but when the content of the color pigment 9 in the coating composition 7 is low, the color pigment coating becomes a translucent coating.

The heat-shielding pigment may be any pigment that reduces the transmittance, reflectance, and absorptance of solar radiation, and is more preferably one that transmits visible light and reduces the transmittance of ultraviolet and infrared rays. Examples of pigments that reduce the transmittance of solar radiation include composite oxide pigments, ceramic pigments, and metal powder pigments.

The size of the granular color pigment 9 or heat-shielding pigment 9 is a primary particle diameter of 5 nm to 100 μm, preferably a primary particle diameter of 10 nm to 10 μm, and more preferably a primary particle diameter of 15 nm to 100 nm.

The solvent 35 is a combination of a volatile solvent 35a that is highly compatible with the pigment-containing coating 50 formed in the pigment-containing coating formation process 3, and a non-volatile solvent 35b that is less compatible with the pigment-containing coating 50.

The volatile solvent 35a may be, for example, a hydrocarbon solvent, an alcohol solvent, an ether, an ester, a ketone, a halogen, or a silicone, and it is desirable that the boiling point at atmospheric pressure is 150°C or less. Specific examples include normal heptane, normal hexane, isohexane, cyclohexane, methylcyclohexane, toluene, xylene, normal octane, methanol, ethanol, normal propanol, isopropanol, normal butyl alcohol, isobutyl alcohol, tetrahydrofuran, methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, and dichloromethane.

The volatile solvent 35a stores the coating composition 7 in a solution state when it is contained in a sealed container, and evaporates when it comes into contact with air when it is applied from the sealed container to the surface of the substrate 8. As a result, when the coating composition 7 starts to be spread on the surface of the substrate 8 with the buff 6, the amount of evaporation is still small, so the coating composition 7 is maintained in a liquid state, making it easier to spread while rubbing the coating composition 7 with the buff 6, and evaporates quickly while making it easier to spread, rapidly reducing the liquid ratio of the coating composition 7, making it easier for the coating composition 7 to become a pigment-containing coating 50 and to be quickly fixed. Thus, the volatile solvent 35a has the function of making it easier to apply the liquid coating composition 7 to the substrate 8 and to fix it.

The non-volatile solvent 35b is, for example, a hydrocarbon solvent, an alcohol solvent, a polyhydric alcohol, or a glycol ether, and it is desirable that the boiling point at atmospheric pressure is 170°C or higher. Specific examples include a mixture of aliphatic hydrocarbons having 9 or more carbon atoms, a mixture of aliphatic cyclic hydrocarbons having 9 or more carbon atoms, benzyl alcohol, ethylene glycol, and propylene glycol.

The non-volatile solvent 35b stores the coating composition 7 in a solution state while it is in a sealed container, and after it is applied from the sealed container to the surface of the substrate 8, when the coating composition 7 is pressed and rotated with the buff 6, it does not evaporate immediately, so it makes it easier to spread the coating composition 7 as a liquid together with the volatile solvent 35a. After that, as shown in FIG. 6(b) or FIG. 7, since the pigment 9 and the moisture-curing fixing component 30 are solid, the solid forms a lower layer, and the liquid non-volatile solvent 35b forms an upper layer. Therefore, even if the upper layer is pressed while rotating with the buff 6, the upper layer of the non-volatile solvent 35b covers the pigment 9, so that the friction between the buff 6 and the pigment-containing coating 50 is reduced, and no scratches are caused on the surface of the layer of the moisture-curing fixing component 30.

To carry out a spreading operation using a buff 6 on the coating composition 7 applied to the surface of a substrate 8 means, as shown in FIG. 3, applying the coating composition 7 to the surface of the substrate 8, and spreading the coating composition 7 applied to the surface of the substrate 8 by rotating R or reciprocating (not shown) while pressing the buff 6. In other words, after applying the coating composition 7 to the surface of the substrate 8, or after applying the coating composition 7 to the buff 6, the buff 6 is used to rub the coating composition 7 against the surface of the substrate 8 to spread the coating.

The tools used to spread the buff 6 include rotary polishers that can accommodate disc-shaped buffs, rotary drill drivers that can accommodate cylindrical or conical buffs, orbital sanders that can accommodate flat buffs and have a reciprocating motion, such as an orbital sander with a pad that swings back and forth and side to side, and a reciprocating linear motion sander with a pad that moves back and forth.

The rotary polisher 5 may be a double action polisher, gear action polisher, or single action polisher, but any other tool that can be fitted with a buff 6 and can apply rotation R may also be used.

The rotation speed R is preferably 200 to 16,000 rpm, more preferably 1,000 to 10,000 rpm, and even more preferably 2,000 to 8,000 rpm. The reciprocating speed is preferably the same as the rotation speed. The reciprocating speed is preferably 100 to 10,000 times/min, more preferably 500 to 8,000 times/min, and even more preferably 1,000 to 3,000 times/min.

The buff 6 may be a urethane buff 6, a wool felt buff 6, or a cotton buff 6. The shape of the buff 6 may be, for example, a disk shape with a hard plate 62 on the back side as shown in FIG. 10(a), or a cone or cylinder shape (not shown) with a hard rotating shaft 61 in the center as shown in FIG. 10(b). However, any shape may be used as long as the front side of the buff 6 can be in contact with the substrate 8.

When the buff 6 is disk-shaped as shown in FIG. 10(a), it is suitable for cases where the surface shape of the substrate 8 is formed into a planar shape, and when it is cone-shaped as shown in FIG. 10(b), it is suitable for cases where the space in which the buff is used is narrow, such as the inner wall surface of a hole or a slit portion, and because it is cone-shaped, it is possible to carry out the spreading work from areas with a narrow slit width to areas with a relatively wide slit width.

Next, the undercoat application process 2 will be described. The undercoat is used as a preparation for applying the coating composition 7 onto the surface of the substrate 8, with the aim of improving adhesion to the surface of the substrate 8, and is applied to the surface of the substrate 8.

Next, the pigment-containing coating formation process 3 will be described. As shown in FIG. 2, the pigment-containing coating formation process 3 is a process for forming a pigment-containing coating 50 on the surface of the substrate 8. The pigment-containing coating 50 may be one layer, two layers, three layers, or any number of layers. For example, in the case of a coating composition 7 with a low content of pigment 9, a translucent layer can be formed with one layer, and in the case of a coating composition 7 with a high content of pigment 9, a layer that conceals the surface of the substrate 8 can be formed with one layer. Depending on the content of pigment 9, it is possible to adjust whether the pigment-containing coating 50 is translucent or opaque. In addition, since it can be made into multiple layers, the thickness of the pigment-containing coating 50 can be increased.

First, step 10 of the first layer of the pigment-containing coating will be described. As shown in Figure 2, the first step is step 11. In step 11, a coating composition 7 containing a pigment 9 is applied to the surface of the substrate 8 or to the surface of the buff 6 as shown in Figure 6(a).

Next, in step 12, as shown in FIG. 3 or FIG. 4, the polisher 5 is rotated R or reciprocated to spread the coating. While the polisher 5 is in contact with the surface of the substrate 8, the coating composition 7 is uniformly spread over the surface of the substrate 8 by rotating R or reciprocating.

At this time, the moisture in the air mixes with the coating composition 7, accelerating the curing reaction of the coating composition 7 on the surface of the substrate 8, and the pigment 9 is fixed to the surface of the substrate 8.

That is, when the buff 6 is pressed against the surface of the substrate 8 to which the coating composition 7 has been applied and rotated, the moisture-curable immobilizing component 30 hardens when it comes into contact with moisture in the air. More specifically, for example, the moisture-curable silicone 31 hardens when it comes into contact with moisture in the air, with the help of the action of the reaction catalyst 32. This hardening causes the moisture-curable immobilizing component 30, for example, the moisture-curable silicone 31 and the reaction catalyst 32 to confine the pigment 9, forming a layer of the moisture-curable immobilizing component 30, for example, the moisture-curable silicone 31 and the reaction catalyst 32, containing the pigment 9, as shown in FIG. 7.

At the same time, the coating composition 7, which was liquid from the time it was placed in the sealed container until it was applied, quickly evaporates the volatile solvent 35a during the spreading process, and the remaining liquid non-volatile solvent 35b forms a layer on top of the layer of solid moisture-curable silicone 31.

The polisher 5 is moved while rotating or reciprocating (not shown) so that the pigment 9 is uniformly spread on the surface of the substrate 8. By repeatedly performing this procedure 12, the pigment 9 is uniformly spread on the surface of the substrate 8, the volatile component 35a of the coating composition 7 is evaporated, and the pigment 9 can be fixed to the surface of the substrate 8 by the moisture-curable fixing component 30, for example, the moisture-curable silicone 31 and the reaction catalyst 32. Then, as shown in FIG. 6(b), in procedure 13, the first layer 51 of the pigment-containing coating 50, which is a layer containing the pigment 9 on the surface of the substrate 8, is completed. At the time when procedure 12 is completed, that is, in procedure 13 at the time when the operation of the polisher 5 is completed, the pigment 9 is fixed to the surface of the substrate 8 by the solid moisture-curable fixing component 30, so a drying process for fixing the pigment 9 is not required.

Here, the layer of the solid moisture-curable immobilization component 30, for example the non-volatile solvent 35b which is the layer on top of the layer of the moisture-curable silicone 31 and the reaction catalyst 32, can be left as is to proceed with the procedure for the second layer, or the non-volatile solvent 35b can be wiped off.

The non-volatile solvent 35b can be wiped off with any material capable of absorbing liquid, such as a buff, sponge, or microfiber cloth. For example, in order to reduce friction with the microfiber cloth, it is preferable to first wipe off the non-volatile solvent 35b with the microfiber cloth moistened with water or the microfiber cloth, and then gradually wipe off the non-volatile solvent 35b with the microfiber cloth that has dried.

Next, the second layer step 20 of the pigment-containing coating 50 will be described. The second layer step 20 involves repeating the same steps as the first layer steps 11, 12, and 13. First, as shown in FIG. 8(a), in step 11, the same coating composition 7 as that applied in step 11 is applied to the surface of the first layer 51. Next, as shown in FIG. 3, in step 12, the polisher 5 is brought into contact with the substrate 8 and the coating composition 7 is spread by rotating R or reciprocating. The polisher 5 is rotated R or reciprocated to spread the coating composition 7 evenly over the surface of the first layer 51. At this time, the liquid non-volatile solvent 35b in the upper layer of the first layer 51 is mixed with the coating composition 7 of the second layer 52. However, the layer of the moisture-curable immobilizing component 30 containing the pigment 9 formed in the first layer, for example, the layer of the moisture-curable silicone 31 and the layer of the reaction catalyst 32, is firmly fixed to the substrate 8 and does not peel off, so it is not mixed with the coating composition 7 of the second layer.

Then, the polisher 5 is moved while applying rotation R or reciprocating motion (not shown) so as to spread the coating composition 7 evenly over the entire surface of the layer of moisture-curable silicone 31 containing the pigment 9 of the first layer 51. Next, in step 13, as shown in FIG. 8(b), the second layer 52 of the pigment-containing coating 50 is completed on the surface of the first layer 51. At the end of step 12, i.e., at the end of step 13 when the operation of the polisher 5 is completed, the pigment 9 is fixed to the surface of the layer of the moisture-curable fixing component 30 of the first layer by the solid moisture-curable fixing component 30, so a drying step for fixing the pigment 9 is not required.

Then, the same procedure as for the first and second layers is repeated for the third, fourth, etc. layers of the pigment-containing coating 50.

Next, after the pigment-containing coating formation process 3, a topcoat application process 4 is carried out in which a topcoat is applied. A transparent coating composition is used as the coating composition. This process is preferably carried out when the coloring is to be prevented from fading, discoloration, or the heat-shielding effect is to be maintained for a long period of time.

As a comparative example, as shown in Figure 9, if paint 70 containing pigment 72 is applied to the surface of substrate 8, for example by brush or spray, the surface of the coating film is soft immediately after brushing or spraying, so if an attempt is made to immediately layer a second layer on top, the coating film will mix with the first layer of coating film, causing a problem that the coating film will be disturbed, and a layered structure cannot be formed. Also, if the coating film is touched immediately after brushing or spraying, the paint will stick to the fingers, so a coating film drying process is essential to fix the paint.

1 Pigment-containing film forming coating method 2 Undercoat application step 3 Pigment-containing film forming step 4 Topcoat application step 5 Polisher 6 Buff 7 Coating composition 8 Substrate 9 Pigment 10 First layer Step 11 Step 12 Step 13 Step 20 Second layer Step 30 Moisture-curable immobilizing component 31 Moisture-curable silicone 32 Reaction catalyst 35 Solvent 35a Volatile solvent 35b Non-volatile solvent 50 Pigment-containing film 51 First layer 52 Second layer 61 Rotating shaft 62 Hard plate 70 Paint 72 Pigment R Rotating

Claims (5)

The method includes a pigment-containing coating formation step in which a coating composition containing a moisture-curable immobilizing component, a pigment, and a solvent is applied to a surface of a substrate, or while the coating composition is being applied, the coating composition is rubbed with a buff against the surface of the substrate to which the coating composition has been applied, thereby spreading the coating composition with the buff, whereby moisture contained in the air and the coating composition are mixed together, accelerating a curing reaction of the coating composition on the surface of the substrate, and the pigment is immobilized on the surface of the substrate,
A coating method for forming a pigment-containing film, characterized in that the solvent is a combination of a volatile solvent that is highly compatible with the pigment-containing film formed in the pigment-containing film forming step and a non-volatile solvent that is less compatible with the pigment-containing film . 2. The coating method for forming a pigment-containing film according to claim 1 , wherein the moisture-curable immobilizing component contained in the coating composition comprises a moisture-curable silicone and a reaction catalyst. The moisture-curable silicone is represented by the following general formula (1):
3. The coating method for forming a pigment-containing film according to claim 2, characterized in that the silicone compound has a chemical structure represented by the formula: (wherein n is an integer of 1 to 10, and each of X's independently represents a halogen atom, a hydrogen atom, methoxy, ethoxy, propoxy, isopropoxy, acetoxy, enoxy, oxime, methyl, ethyl, propyl, isopropyl, normal hexyl, cyclohexyl, normal octyl, normal decyl, phenyl, vinyl, allyl, parastyl, 3-glycidoxypropyl, 2-(3,4-epoxycyclohexylethyl, 3-aminopropyl, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyl, N-phenyl-3-aminoethyl-3-aminopropyl, 3-methacryloxypropyl, 3-acryloxypropyl, 3-mercaptopropyl, 3-ureidopropyl, 3 -isocyanatopropyl, isocyanurate, or an acid anhydride). 4. The coating method for forming a pigment-containing film according to claim 1 , further comprising an undercoat application step of applying an undercoat to the surface of the substrate before applying the coating composition. 5. The coating method for forming a pigment-containing film according to claim 1 , further comprising a topcoat application step of applying a topcoat to the surface of the formed pigment-containing film.

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