Multipurpose aqueous solvent composition and repainting method

Abstract

To provide multipurpose aqueous solvent composition that makes adhesion to an old coating film of repainting normal temperature dry type aqueous coating excellent, for repainting constructions using a normal temperature dry type aqueous coating, and also makes washability of a washing tools used for repainting excellent.SOLUTION: A multipurpose aqueous solvent composition for repainting by applying a normal temperature dry type aqueous coating on an old coating film surface on a substrate, which contains at least one organic solvent (A) selected from the group consisting of alcohol-based organic solvents, ether-based organic solvents, ketone-based organic solvents, and ester-based organic solvents, an amine compound (B), and water, wherein a content of organic solvent (A) is 1 to 50 mass%, the content of amine compound (B) is 0.05 to 10 mass%, and the solid content concentration of the aqueous solvent composition is either 0 mass% or less than 0.5 mass%.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a multi-purpose aqueous solvent composition and a repainting method that can support the repainting operation of a room temperature drying type aqueous paint in a plurality of stages.

Background Art

[0002] In recent years, due to environmental protection, the maintenance of the interior and exterior walls and roofs of buildings has been reviewed, and repainting to restore the strength of deteriorated old paint films has attracted attention. At the repainting site, after cleaning the dust on the old paint film by high-pressure water washing or after light scarring work followed by high-pressure water washing, the work of applying a paint for repainting is carried out.

[0003] Conventionally, when repainting a deteriorated old paint film in a building, a solvent-based sealer composition was used to apply, penetrate, solidify, and reinforce the deteriorated old paint film surface, and then a topcoat paint or a primer called an undercoat paint was applied.

[0004] Since solvent-based sealers containing a large amount of organic solvents have problems in terms of safety and hygiene and odors, although water-based sealer compositions have been desired, they have not reached solvent-based sealers in terms of permeability to old paint films, peel resistance, and blister resistance after construction, and their practicality has been low.

[0005] As an example of an aqueous sealer composition, Patent Document 1 discloses an aqueous solution or aqueous dispersion of a carbonyl group-containing copolymer obtained by copolymerizing a monomer mixture containing (a) 30 to 95% by weight of a carbonyl group-containing monomer, (b) 0 to 25% by weight of an ionic group-containing monomer, (c) 5 to 50% by weight of an alkyl ester of acrylic acid or methacrylic acid having 12 to 30 carbon atoms, and (d) 0 to 65% by weight of other copolymerizable monomers, and adding a hydrazide compound containing two or more hydrazide groups in one molecule as a crosslinking agent so that the hydrazide group is 0.05 to 2 equivalents per equivalent of the carbonyl group. Also disclosed is a method for strengthening a fragile surface or deteriorated surface by applying this to the fragile surface or deteriorated surface, allowing it to penetrate, and solidifying it.

[0006] Also, at the site of repainting a building, after the painting contractor finishes treating the old paint film, they mix a diluent into the paint prepared for repainting, adjust the viscosity to a suitable level for painting, and then perform the painting.

[0007] In the case of aqueous paints, usually tap water is used as the diluent, but in recent years, the development of diluents has also been carried out. For example, Patent Document 2 discloses a multi-liquid type aqueous paint having a first liquid containing an acid group-containing resin, a pigment, and water having a pH in the range of 6 to 9 and a solid content in the range of 20 to 50% by mass and being water-soluble or water-dispersible, and a second liquid having a solid content in the range of 0.5 to 10% by mass, a water content of 70% by mass or more, and a pH at least 0.5 higher than that of the first liquid and containing a neutralizing agent, a thickening agent, and water.

[0008] Also, at the site of repainting a building, after the painting contractor applies the adjusted paint, they wash the painting tools such as rollers and brushes (brushes) used for painting.

[0009] As a technology related to a cleaning agent for aqueous paints, for example, Patent Document 3 discloses an aqueous paint cleaning agent characterized by containing potassium hydroxide at a concentration of 0.21% by weight or more and 1.4% by weight or less, butyl cellosolve at a concentration of 12% by weight or more and 49% by weight or less, and water.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0011] From the viewpoints of being built outdoors and being immovable, and environmental consideration, room temperature-drying type water-based paints are often used for repainting existing buildings. On the other hand, "building materials", which are materials before construction, such as ceramic or metal siding used for outer walls and metal materials used for roofs, are painted at places such as factories and can be heat-dried. Therefore, a heat-curing type coating film may be formed. Thus, even for the old coating film of a building, the materials of the base material and the old coating film are diverse depending on the type of building material, etc. The paint supplier recommends painting specifications to the painting contractor according to the types and states of the base material and the old coating film. Also, in summer, etc., since the surface temperature of the old coating film on the metal-based base material becomes high, if a water-based paint for repainting is applied after treating with a water-based sealer as described in Patent Document 1, the water-based paint will be applied in a situation where drying is unusually fast, and coating film abnormalities such as poor finish and peeling will occur. And, the paint strongly adheres to the paintbrushes and rollers that have come into contact with such a high-temperature old coating film, making cleaning insufficient, and there is a problem that these painting tools cannot be reused.

[0012] The present invention has been made in view of the above problems, and for performing repainting using a room temperature-drying type water-based paint, it aims to provide a multi-purpose type water-based solvent composition that has good adhesion to the old coating film of the room temperature-drying type water-based paint for repainting and is also excellent in the cleanability of the painting tools used for repainting.

Means for Solving the Problems

[0013] Since each of the compositions described in Patent Documents 1 to 3 is designed according to its respective purpose, there is no idea of using them for other purposes. For example, although the aqueous sealer described in Patent Document 1 can be applied as an old coating film treatment agent to an old coating film made of a room temperature drying type paint, its use as a diluent for a repainting paint is not assumed. Although the diluent described in Patent Document 2 can be applied as a diluent to the specific aqueous paint described in Patent Document 2, its use as a cleaning agent for painting equipment is not assumed. Further, although the cleaning agent described in Patent Document 3 is excellent as a cleaning agent for cleaning painting equipment, its application to an old coating film or its use as a diluent is not assumed.

[0014] The present inventors have studied the above-mentioned various problems that occur in each stage of repainting a building. As a result, an aqueous solvent composition containing at least one organic solvent (A) selected from the group consisting of an alcohol-based organic solvent, an ether-based organic solvent, a ketone-based organic solvent, and an ester-based organic solvent, an amine compound (B), and water, wherein the content of the organic solvent (A) is 1 to 50% by mass and the content of the amine compound (B) is 0.05 to 10% by mass with respect to the total amount of the aqueous solvent composition, and the solid content concentration of the aqueous solvent composition is 0% by mass or less than 0.5% by mass, has been found to improve the adhesion to an old coating film of a room temperature drying type aqueous paint for repainting and to be excellent in cleanability of painting equipment and the like.

[0015] That is, the present invention includes the following embodiments. Item 1. A multi-purpose aqueous solvent composition used for applying a room temperature drying type aqueous paint to an old coating film surface on a substrate for repainting, containing at least one organic solvent (A) selected from the group consisting of an alcohol-based organic solvent, an ether-based organic solvent, a ketone-based organic solvent, and an ester-based organic solvent, an amine compound (B), and water and The content of the organic solvent (A) is 1 to 50% by mass and the content of the amine compound (B) is 0.05 to 10% by mass with respect to the total amount of the aqueous solvent composition, An aqueous solvent composition in which the solid content concentration of the aqueous solvent composition is 0% by mass or less than 0.5% by mass. Item 2. The aqueous solvent composition according to Item 1, which is a combined type that can be used in any two or more of the old coating film treatment step, paint preparation step, and cleaning step in the repainting. Item 3. A repainting method including an old coating film treatment step of applying the aqueous solvent composition according to Item 1 or 2 to an old coating film on a substrate and allowing the aqueous solvent composition to penetrate into the old coating film. Item 4. A repainting method including an old coating film treatment step of applying the aqueous solvent composition according to Item 1 or 2 to an old coating film on a metal substrate and allowing the aqueous solvent composition to penetrate into the old coating film. Item 5. A repainting method including an old coating film treatment step of applying the aqueous solvent composition according to Item 1 or 2 to an old coating film formed by a heat-curable paint on a metal substrate and allowing the aqueous solvent composition to penetrate into the old coating film. Item 6. A repainting method including a step of applying a diluted paint obtained by mixing a room temperature drying type aqueous paint and the aqueous solvent composition according to Item 1 or 2 to an old coating film on a substrate. Item 7. A single-layer finishing repainting method using an aqueous solvent composition and a room temperature drying type aqueous paint for an old coating film on a substrate, applying an aqueous solvent composition to an old coating film on a substrate and allowing the aqueous solvent composition to penetrate into the old coating film, and applying a room temperature drying type aqueous paint to the old coating film into which the aqueous solvent composition has penetrated. Item 8. A single-layer finishing repainting method using an aqueous solvent composition and a room temperature drying type aqueous paint for an old coating film on a substrate, applying an aqueous solvent composition to an old coating film on a substrate and allowing the aqueous solvent composition to penetrate into the old coating film, and Applying a diluted paint, which is a mixture of a room temperature drying type water-based paint and the present water-based solvent composition, to an old paint film that has been infiltrated with the water-based solvent composition A repainting method comprising the above Item 9. A single-layer finishing repainting method using a water-based solvent composition and a room temperature drying type water-based paint for an old paint film on a substrate, comprising Applying a diluted paint, which is a mixture of a room temperature drying type water-based paint and a water-based solvent composition, to an old paint film on a substrate Item 10. A multi-layer coating finishing repainting method using the water-based solvent composition and the room temperature drying type water-based paint according to Item 1 or 2 for an old paint film on a substrate, wherein the room temperature drying type water-based paint includes a room temperature drying type water-based primer paint and a room temperature drying type water-based topcoat paint, and the method comprises Applying the water-based solvent composition according to Item 1 or 2 to an old paint film on a substrate and infiltrating the water-based solvent composition according to Item 1 or 2 into the old paint film Applying a room temperature drying type water-based primer paint to the old paint film that has been infiltrated with the water-based solvent composition to form a primer paint film, and Applying a room temperature drying type water-based topcoat paint onto the formed primer paint film A repainting method comprising the above Item 11. A multi-layer coating finishing repainting method using the water-based solvent composition and the room temperature drying type water-based paint according to Item 1 or 2 for an old paint film on a substrate, wherein the room temperature drying type water-based paint includes a room temperature drying type water-based primer paint and a room temperature drying type water-based topcoat paint, and the method comprises Applying the water-based solvent composition according to Item 1 or 2 to an old paint film on a substrate and infiltrating the water-based solvent composition according to Item 1 or 2 into the old paint film Applying a room temperature drying type water-based primer paint to the old paint film that has been infiltrated with the water-based solvent composition to form a primer paint film, and Applying a diluted paint, which is a mixture of a room temperature drying type water-based topcoat paint and the water-based solvent composition according to Item 1 or 2, onto the formed primer paint film A repainting method comprising the above Item 12. A repainting method for a multilayer coating finish using the aqueous solvent composition according to claim 1 or 2 and a room temperature drying type aqueous paint on an old coating film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous primer paint and a room temperature drying type aqueous topcoat paint, and the method comprises: Applying the aqueous solvent composition according to claim 1 or 2 to the old coating film on the substrate and allowing the aqueous solvent composition according to claim 1 or 2 to penetrate into the old coating film; Coating a diluted paint obtained by mixing a room temperature drying type aqueous primer paint and the aqueous solvent composition according to claim 1 or 2 on the old coating film into which the aqueous solvent composition has penetrated to form a primer coating film; and Coating a room temperature drying type aqueous topcoat paint on the formed primer coating film. A repainting method comprising the above steps. Item 13. A repainting method for a multilayer coating finish using the aqueous solvent composition according to claim 1 or 2 and a room temperature drying type aqueous paint on an old coating film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous primer paint and a room temperature drying type aqueous topcoat paint, and the method comprises: Applying the aqueous solvent composition according to claim 1 or 2 to the old coating film on the substrate and allowing the aqueous solvent composition according to claim 1 or 2 to penetrate into the old coating film; Coating a diluted paint obtained by mixing a room temperature drying type aqueous primer paint and the aqueous solvent composition according to claim 1 or 2 on the old coating film into which the aqueous solvent composition has penetrated to form a primer coating film; and Coating a diluted paint obtained by mixing a room temperature drying type aqueous topcoat paint and the aqueous solvent composition according to claim 1 or 2 on the formed primer coating film. A repainting method comprising the above steps. Item 14. A repainting method for a multilayer coating finish using the aqueous solvent composition according to claim 1 or 2 and a room temperature drying type aqueous paint on an old coating film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous primer paint and a room temperature drying type aqueous topcoat paint, and the method comprises: Coating a diluted paint obtained by mixing a room temperature drying type aqueous primer paint and the aqueous solvent composition according to claim 1 or 2 on the old coating film on the substrate to form a primer coating film; and Applying a room-temperature drying type water-based topcoat paint onto the formed undercoat film. A repainting method comprising the above. Item 15. A repainting method for a multi-layer coating finish using the water-based solvent composition and the room-temperature drying type water-based paint according to Item 1 or 2 on an old paint film on a substrate, wherein the room-temperature drying type water-based paint includes a room-temperature drying type water-based undercoat paint and a room-temperature drying type water-based topcoat paint, and the method comprises: Applying a room-temperature drying type water-based undercoat paint onto the old paint film on the substrate to form an undercoat film, and Applying a diluted paint formed by mixing a room-temperature drying type water-based topcoat paint and the water-based solvent composition according to Item 1 or 2 onto the formed undercoat film. A repainting method comprising the above. Item 16. A repainting method for a multi-layer coating finish using the water-based solvent composition and the room-temperature drying type water-based paint according to Item 1 or 2 on an old paint film on a substrate, wherein the room-temperature drying type water-based paint includes a room-temperature drying type water-based undercoat paint and a room-temperature drying type water-based topcoat paint, and the method comprises: Applying a diluted paint formed by mixing a room-temperature drying type water-based undercoat paint and the water-based solvent composition according to Item 1 or 2 onto the old paint film on the substrate to form an undercoat film, and Applying a diluted paint formed by mixing a room-temperature drying type water-based topcoat paint and the water-based solvent composition according to Item 1 or 2 onto the formed undercoat film. A repainting method comprising the above. Item 17. A cleaning method comprising removing the room-temperature drying type water-based paint adhering to the painting tool using the water-based solvent composition according to Item 1 or 2 after performing repainting by applying the room-temperature drying type water-based paint onto the surface of the old paint film on the substrate with a painting tool. Item 18. A storage method for a painting tool, which comprises cleaning the painting tool with the water-based solvent composition according to Item 1 or 2 and immersing it in the water-based solvent composition according to Item 1 or 2 after performing repainting by applying the room-temperature drying type water-based paint onto the surface of the old paint film on the substrate with a painting tool.

Advantages of the Invention

[0016] The aqueous solvent composition of the present invention improves the adhesion between the coating film formed by a room-temperature drying type aqueous paint for repainting and the old coating film, and also has excellent cleanability of the painting equipment. As a result, since this aqueous solvent composition can be used in a multi-purpose and combined manner, it can contribute to space saving in a narrow painting site and provide an environment in which it is easy for workers to perform painting work. Further, since this aqueous solvent composition is an aqueous composition, consideration is also given to the safety of workers.

Mode for Carrying Out the Invention

[0017] This embodiment is a multi-purpose type aqueous solvent composition used for repainting by applying a room-temperature drying type aqueous paint to the surface of an old coating film on a substrate.

[0018] Base material The substrate is not particularly limited in terms of material and shape as long as it is a component of a building. For example, inorganic substrates other than metals such as cement, mortar, concrete, slate, gypsum, calcium silicate, glass, ceramics, tiles, marble, artificial marble, etc.; woody substrates such as wood; metal substrates such as steel, galvanized steel, tin-plated steel, stainless steel, magnesium alloy, aluminum, aluminum alloy, titanium, titanium alloy, tinplate, metal siding, etc.; plastic substrates such as acrylic plate, polyvinyl chloride plate, polycarbonate plate, ABS plate, polyethylene terephthalate plate, polyolefin plate, etc.; composite substrates combining these substrates; and the like. Examples of the composite substrate include ceramic siding such as wood fiber reinforced cement board, fiber reinforced cement board, fiber reinforced cement-calcium silicate board, etc.

[0019] Examples of the substrate to be repainted include the wall surface, roof surface, floor surface, ceiling, column, door, gate, etc. of buildings such as houses, buildings, public facilities, commercial facilities, warehouses, etc.

[0020] Old coating film The old coating film means the coating film that already exists on the substrate when repainting is carried out. In this embodiment, there is no limitation on the old coating film, and examples include coating films formed from conventionally known paints. The paint may be a heat-curing paint or a room-temperature drying paint, and may be either an aqueous paint or an organic solvent-based paint.

[0021] Room temperature drying type water-based paint A room-temperature drying type aqueous paint is a paint that forms a coating film by drying at room temperature, and refers to a paint that uses water as the main diluting medium. Room temperature varies greatly depending on the atmospheric temperature of the environment where painting is carried out, but refers to a temperature at which no temperature operation such as forced heating or cooling is performed. Since the aqueous solvent composition of this embodiment contains a specific organic solvent (A), an amine compound (B), and water in specific amounts, it has appropriate hydrophilicity, hydrophobicity, and basicity. For this reason, it can be miscible with a wide variety of aqueous paints and can exhibit multi-purpose effects. The room-temperature drying type aqueous paint may be a lacquer paint or a reaction-curing type, and may be a one-component type or a two-component type.

[0022] As the aqueous resin serving as the binder of the room-temperature drying type aqueous paint, a resin that can be dissolved or dispersed in water is used. Examples of such resins include acrylic resins, vinyl resins, silicone resins, fluorine resins, polyurethane resins, epoxy resins, amino group-containing resins, phenolic resins, polyester resins, alkyd resins, polycarbonate resins, and the like. These can be used alone or in combination of two or more. These resins may be those in which two or more are modified or graft-polymerized. Further, when the above aqueous resin is in the form of dispersed particles, it may be either in a single-layer form or in a multi-layer form such as a core-shell type.

[0023] The room-temperature drying type water-based paint may optionally contain a crosslinking agent capable of reacting with the water-based resin. Examples of the crosslinking agent include known crosslinking agents, specifically, for example, polyhydrazide compounds, polysemicarbazide compounds, carbodiimide group-containing compounds, oxazoline group-containing compounds, epoxy group-containing resins, amino group-containing resins, and the like.

[0024] In addition to the water-based resin, water, and the crosslinking agent optionally blended therein, the room-temperature drying type water-based paint optionally contains pigments such as coloring pigments, extender pigments, and rust preventive pigments, and paint additives such as dispersants, plasticizers, film-forming aids, thickeners, defoamers, flame retardants, and neutralizing agents.

[0025] In this embodiment, the room-temperature drying type water-based paint may be either an undercoat paint or a topcoat paint. The room-temperature drying type water-based paint used as an undercoat paint is also referred to as a room-temperature drying type water-based undercoat paint, and the room-temperature drying type water-based paint used as a topcoat paint is also referred to as a room-temperature drying type water-based topcoat paint.

[0026] In this specification, an undercoat paint is a paint that is directly applied onto an old paint film that may have been treated with the aqueous solvent composition of the present invention, and is located in the lower layer of a multi-layer finish where another paint is applied thereon, and is sometimes generally referred to as a primer, a substrate conditioner, a filler, or a surfacer.

[0027] In this specification, a topcoat paint is a paint provided above the undercoat paint, and is a paint located in the uppermost layer or an intermediate layer, and is sometimes generally referred to as an intermediate coat paint, a top coat, or a multi-layer finish coating material.

[0028] Water-based solvent composition Next, the aqueous solvent composition of the present invention will be described. The aqueous solvent composition contains at least one organic solvent (A) selected from the group consisting of alcohol-based organic solvents, ether-based organic solvents, ketone-based organic solvents, and ester-based organic solvents, a water-soluble amine compound (B), and water. The content of the organic solvent (A) is 1 to 50% by mass based on the total amount of the aqueous solvent composition, and the content of the water-soluble amine compound (B) is 0.05 to 10% by mass, and the solid content concentration of the aqueous solvent composition is 0% by mass or less than 0.5% by mass.

[0029] Water The aqueous solvent composition contains water. The content of water is 40 to 98.95% by mass, preferably 50 to 98% by mass, more preferably 60 to 95% by mass based on the total amount of the aqueous solvent composition. When the content of water is 40% by mass or more based on the total amount of the aqueous solvent composition, the painting workability of the repainting water-based paint, the adhesion to the old paint film of the water-based paint, and the cleanability of the painting equipment can be improved. When the content of water is 99.85% by mass or less based on the total amount of the aqueous solvent composition, components other than water can be contained in the aqueous solvent composition, and the painting workability of the water-based paint, the adhesion to the old paint film of the water-based paint, and the cleanability of the painting equipment can be improved.

[0030] Organic solvent (A) The organic solvent (A) is at least one selected from the group consisting of alcohol-based organic solvents, ether-based organic solvents, ketone-based organic solvents, and ester-based organic solvents.

[0031] Examples of the alcohol-based organic solvent include monohydric alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 3-methoxy-3-methyl-1-butanol; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, glycerin, and trimethylolpropane.

[0032] Examples of the ether-based organic solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether; tetrahydrofuran, 1,4-dioxane, anisole, and the like.

[0033] Examples of the ketone-based organic solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl-n-amyl ketone, and the like.

[0034] Examples of the ester-based organic solvent include methyl acetate, ethyl acetate, butyl acetate, and the like.

[0035] The above organic solvents can be used alone or in combination of two or more.

[0036] In this embodiment, from the viewpoints of the adhesion of the room-temperature drying type water-based paint for repainting to the old paint film and the cleanability of the painting equipment, the content of the organic solvent (A) relative to the total amount of the water-based solvent composition is 1 to 50% by mass, preferably 10 to 40% by mass. When the content of the organic solvent (A) relative to the total amount of the water-based solvent composition is less than 1% by mass, the adhesion of the water-based paint to the old paint film and the cleanability of the painting equipment may decrease. When the content of the organic solvent (A) relative to the total amount of the water-based solvent composition exceeds 50% by mass, the cleanability of the painting equipment may decrease.

[0037] Amine compound (B) The amine compound (B) can be used as long as it is a compound having at least one amino group in the molecule. When the water-based solvent composition contains the amine compound (B), the adhesion of the water-based paint to the old paint film treated with the water-based solvent composition is improved, the painting equipment to which the room-temperature drying type water-based paint adheres can be cleaned well using the water-based solvent composition, and there is an effect that spoilage when the painting equipment is left for a long time can be prevented or suppressed.

[0038] Examples of the amine compound include amine compounds such as aliphatic, alicyclic, aromatic, and heterocyclic amine compounds, fatty acid-modified products of the amine compounds, amine adducts with epoxy compounds, Mannich-modified products, Michael adducts, ketimines, and aldimines, which are also included in the amine compounds, and commercially available water-based amine curing agents are also applicable.

[0039] From the viewpoints of the adhesion of the water-based paint to the old paint film treated with the water-based solvent composition and the good cleanability of the painting equipment to which the water-based paint adheres by the water-based solvent composition, the amine compound (B) is preferably at least one selected from the group consisting of dimethylamine, triethylamine, diethylamine, dimethylaminopropylamine, ethylenediamine, diethylenetriamine, ethanolamine, diethanolamine, triethanolamine, morpholine, aminopropanol, 2-amino-2-methyl-1-propanol, 2-dimethylaminoethanol, dimethylaminopropylamine, and combinations thereof.

[0040] In this embodiment, from the viewpoint of ensuring good adhesion of the room-temperature drying type water-based paint for repainting to the old paint film and excellent cleanability of the painting tools used, the content of the amine compound (B) relative to the total amount of the aqueous solvent composition is 0.05 to 10% by mass, preferably 0.1 to 5% by mass. When the content of the amine compound (B) relative to the total amount of the aqueous solvent composition is less than 0.05% by mass, the adhesion of the water-based paint to the old paint film and the cleanability of the painting tools may deteriorate. When the content of the amine compound (B) relative to the total amount of the aqueous solvent composition exceeds 10% by mass, the adhesion of the water-based paint to the old paint film may deteriorate.

[0041] Solid content concentration In this embodiment, the aqueous solvent composition has a solid content concentration of 0% by mass or less than 0.5% by mass, preferably more than 0 and less than 0.5% by mass, more preferably less than 0.3% by mass, and particularly preferably less than 0.1% by mass. When the solid content concentration exceeds 0.5% by mass, the adhesion between the paint film formed by the room-temperature drying type water-based paint for repainting and the old paint film is insufficient, and at least one of the insufficient cleanability of the painting tools and the spoilage when the painting tools are left for a long time may occur, which is not preferable.

[0042] In this specification, the solid content means the residue obtained by removing volatile components such as water and organic solvents from the sample. The solid content concentration is the mass ratio of the solid content (non-volatile content) contained in the sample. For example, it can be obtained by spreading about 3 grams of the sample on an aluminum dish and dividing the mass of the residue dried at 105°C for 3 hours by the mass before drying.

[0043] In addition to the organic solvent (A), the amine compound (B), and water, the aqueous solvent composition of the present invention may contain, as required and within the scope of the present invention, organic solvents other than the organic solvent (A), aqueous resins, dispersants, defoamers, film-forming aids, rheology control agents, preservatives, antifreeze agents, and other paint additives. It may also contain inevitable impurities contained when the organic solvent (A) and the amine compound (B) are industrially obtained.

[0044] Multi-purpose type The aqueous solvent composition is of a multi-purpose type. The repainting of a building involves multiple stages including an old coating film treatment process, a paint preparation process, a painting process, a drying process, a cleaning process, etc. In this specification, the multi-purpose type means that the aqueous solvent composition can be applied in multiple of these stages. More specifically, the multi-purpose type refers to a combined type that can be used in any two or more of the old coating film treatment process, the paint preparation process, and the cleaning process. For example, at a painting site, a certain operator uses this aqueous solvent composition in the old coating film treatment process for repainting the metal exterior wall, and another operator washes the paintbrushes used for repainting the inorganic exterior wall with this aqueous solvent composition; a certain operator uses this aqueous solvent composition in the old coating film treatment process for repainting the metal exterior wall, and another operator uses this aqueous solvent composition in the paint preparation process for the inorganic exterior wall. In cases where the objects to be repainted and the painters are different at an integrated painting construction site, the aqueous solvent composition is used in multiple stages, so it meets the multi-purpose type.

[0045] Hereinafter, each step of the repainting method using the aqueous solvent composition of the present invention will be described.

[0046] Old coating film treatment process In some embodiments, the above aqueous solvent composition can be used as a treatment agent for old coating films.

[0047] In a part of this embodiment, the aqueous solvent composition is applied to the old coating film to penetrate the old coating film.

[0048] It is desirable to perform high-pressure water washing and / or keren work on the old coating film as needed depending on the state of deterioration.

[0049] The method of applying the present aqueous solvent composition to the old coating film is not particularly limited, and generally, the methods applied when applying paints can be used. Specifically, there are air spray painting, airless spray painting, painting using a roller, a brush, flow coating, etc. After application, it is usually left at room temperature for natural drying, but forced drying may be performed if necessary. The standing time is preferably 1 second to 3 hours, more preferably 10 seconds to 2 hours.

[0050] In an embodiment having an old coating film treatment step, the effect is more exerted when the substrate is a metal substrate. As described above, there is no limitation on the type of the substrate in this embodiment. However, when the substrate is a metal substrate, the surface temperature of the old coating film becomes extremely high in summer or the like. In such an environment, by applying the aqueous solvent composition to the old coating film prior to repainting with a room temperature drying type aqueous paint, a repainted coating film of more stable quality is formed. This is because the aqueous solvent composition penetrates into the old coating film to soften or partially dissolve the old coating film, and the aqueous solvent composition remaining partially in the old coating film and the room temperature drying type aqueous paint for repainting are mixed on the old coating film, and it is presumed that the solvent evaporation rate in film formation can be alleviated even in a situation where drying is unusually fast.

[0051] Further, in this embodiment, when the old coating film is an old coating film formed by a heat-curable paint, the effect can be more exerted, which is preferable.

[0052] As described above, there is no limitation on the type of the old coating film in this embodiment. However, when the old coating film is formed by a heat-curable paint, there are many points where the degree of crosslinking and the material of the coating film are greatly different from those of the room temperature drying type paint. Therefore, due to the large difference in physical and chemical properties between the old coating film formed by the heat-curable paint and the repainted coating film formed by the room temperature drying type aqueous paint, peeling or film defects such as blistering are likely to occur between them. It is presumed that the aqueous solvent composition penetrates into the old coating film to partially soften or partially dissolve the old coating film, and the adhesiveness between the two is improved.

[0053] As a heat-curable paint, it is a paint that cures by performing forced heating. For example, amine-based paints, blocked polyisocyanate-based paints, powder paints, etc. can be mentioned.

[0054] Paint preparation process The room-temperature drying type water-based paint used in the repainting method of this embodiment is mixed with this water-based solvent composition and diluted as necessary.

[0055] In the diluted paint, as the usage ratio of the room-temperature drying type water-based paint and the water-based solvent composition, it is preferable that the water-based solvent composition is 1 to 30 parts by mass, particularly 2 to 20 parts by mass, with respect to 100 parts by mass of the room-temperature drying type water-based paint. When preparing the paint, in addition to the water-based solvent composition, water, a rheology control agent, etc. may be added.

[0056] In this embodiment, by applying a diluted paint obtained by mixing a room-temperature drying type water-based paint and a water-based solvent composition to the old paint film on the base material, the water-based solvent composition contained in the diluted paint penetrates into the old paint film, and the adhesion between the old paint film and the paint film formed by the room-temperature drying type water-based paint is improved, and at the same time, the workability of applying the diluted paint is improved, which is preferable.

[0057] Painting process In this embodiment, as long as it is within the scope of the present invention, the room-temperature drying type water-based paint may be applied without dilution, diluted with this water-based solvent composition, or diluted with a known diluent other than the water-based solvent composition such as water.

[0058] The method of applying a room-temperature drying type water-based paint, which may be diluted with respect to the old paint film, is not particularly limited, and generally, a method applied when applying paint can be used. Specifically, examples include air spray painting, airless spray painting, painting using a roller, a brush, flow coating, etc. In a specific embodiment, it is applied by a painting tool such as a roller or a brush. After painting, it is usually left at room temperature for natural drying, but forced drying may be performed if necessary. Room temperature refers to a temperature at which no temperature operation such as forced heating or cooling is performed, although it varies greatly depending on the atmospheric temperature of the environment where the painting is performed.

[0059] In the repainting method of the present embodiment, a single-layer finish using a room-temperature drying type water-based paint may be performed, or a multi-layer painting finish may be performed. Single-layer finish refers to performing repainting with one type of room-temperature drying type water-based paint. Multi-layer finish refers to performing repainting with two or more types of room-temperature drying type water-based paints.

[0060] Single-layer finish repainting process In the present embodiment, when performing a single-layer finish repainting using an aqueous solvent composition and a room-temperature drying type water-based paint on an old paint film on a substrate, For the old paint film (I) treated with the aqueous solvent composition, Examples include cases where an aqueous paint (1) diluted with the aqueous solvent composition or an aqueous paint (2) not diluted with the present aqueous solvent composition is applied, For the old paint film (II) not treated with the aqueous solvent composition, Examples include cases where an aqueous paint (1) diluted with the aqueous solvent composition is applied.

[0061] Among them, A repainting method for a single-layer finish using an aqueous solvent composition and a room-temperature drying type water-based paint on an old paint film on a substrate, comprising applying the aqueous solvent composition to the old paint film on the substrate, infiltrating the aqueous solvent composition into the old paint film, and applying a room-temperature drying type water-based paint to the old paint film infiltrated with the aqueous solvent composition; and A repainting method with a single-layer finish using an aqueous solvent composition and a room-temperature drying type aqueous paint for an old paint film on a substrate, wherein the aqueous solvent composition is applied to the old paint film on the substrate, and the old paint film is penetrated with the aqueous solvent composition, and a diluted paint obtained by mixing a room-temperature drying type aqueous paint and the aqueous solvent composition is applied to the old paint film penetrated with the aqueous solvent composition; a repainting method including is a particularly preferred embodiment. Also, A repainting method with a single-layer finish using this aqueous solvent composition and a room-temperature drying type aqueous paint for an old paint film on a substrate, including applying a diluted paint obtained by mixing a room-temperature drying type aqueous paint and the aqueous solvent composition to the old paint film on the substrate is also preferred.

[0062] Multi-layer coating finish repainting process Also, the aqueous solvent composition can also be applied to the repainting of a multi-layer coating finish.

[0063] Therefore, when performing repainting with a multi-layer coating finish using an aqueous solvent composition, a room-temperature drying type aqueous primer paint, and a room-temperature drying type aqueous topcoat paint on an old paint film on a substrate, For the old paint film (I) treated with the aqueous solvent composition, the primer paint (1) diluted with the aqueous solvent composition and the topcoat paint (3) diluted with the aqueous solvent composition, the primer paint (2) not diluted with the aqueous solvent composition and the topcoat paint (3) diluted with the aqueous solvent composition, the primer paint (1) diluted with the aqueous solvent composition and the topcoat paint (4) not diluted with the aqueous solvent composition, the primer paint (2) not diluted with the aqueous solvent composition and the topcoat paint (4) not diluted with the aqueous solvent composition are examples of cases where painting is performed, For the old paint film (II) not treated with the aqueous solvent composition, The undercoat paint (1) diluted with the aqueous solvent composition and the topcoat paint (3) diluted with the aqueous solvent composition, The undercoat paint (2) not diluted with the aqueous solvent composition and the topcoat paint (3) diluted with the aqueous solvent composition, The undercoat paint (1) diluted with the aqueous solvent composition and the topcoat paint (4) not diluted with the aqueous solvent composition, There may be mentioned cases where they are applied.

[0064] Among them, A repainting method for multi-layer coating finish using an aqueous solvent composition, a room temperature drying type aqueous undercoat paint and a room temperature drying type aqueous paint on an old coating film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous undercoat paint and a room temperature drying type aqueous topcoat paint, and the above method comprises applying the aqueous solvent composition to the old coating film on the substrate and allowing the aqueous solvent composition to penetrate into the old coating film; applying the room temperature drying type aqueous undercoat paint to the old coating film into which the aqueous solvent composition has penetrated to form an undercoat film; and applying the room temperature drying type aqueous topcoat paint onto the formed undercoat film. A repainting method for multi-layer coating finish using an aqueous solvent composition and a room temperature drying type aqueous paint on an old coating film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous undercoat paint and a room temperature drying type aqueous topcoat paint, and the above method comprises applying the aqueous solvent composition to the old coating film on the substrate and allowing the aqueous solvent composition to penetrate into the old coating film; applying the room temperature drying type aqueous undercoat paint to the old coating film into which the aqueous solvent composition has penetrated to form an undercoat film; and applying a diluted paint obtained by mixing the room temperature drying type aqueous topcoat paint and the aqueous solvent composition onto the formed undercoat film. A repainting method for a multi-layer coating finish using an aqueous solvent composition and a room temperature drying type aqueous paint on an old paint film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous primer paint and a room temperature drying type aqueous topcoat paint, and the method includes applying the aqueous solvent composition to the old paint film on the substrate, allowing the aqueous solvent composition to penetrate into the old paint film, applying a diluted paint formed by mixing the room temperature drying type aqueous primer paint and the aqueous solvent composition to the old paint film into which the aqueous solvent composition has penetrated to form a primer paint film, and applying the room temperature drying type aqueous topcoat paint on the formed primer paint film; and A repainting method for a multi-layer coating finish using an aqueous solvent composition and a room temperature drying type aqueous paint on an old paint film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous primer paint and a room temperature drying type aqueous topcoat paint, and the method includes applying the aqueous solvent composition to the old paint film on the substrate, allowing the aqueous solvent composition to penetrate into the old paint film, applying a diluted paint formed by mixing the room temperature drying type aqueous primer paint and the aqueous solvent composition to the old paint film into which the aqueous solvent composition has penetrated, applying a diluted paint formed by mixing the room temperature drying type aqueous topcoat paint and the aqueous solvent composition on the formed primer paint film; is a particularly preferred embodiment. Also, A repainting method for a multi-layer coating finish using an aqueous solvent composition and a room temperature drying type aqueous paint on an old paint film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous primer paint and a room temperature drying type aqueous topcoat paint, and the method includes applying a diluted paint formed by mixing the room temperature drying type aqueous primer paint and the aqueous solvent composition to the old paint film on the substrate to form a primer paint film, and applying the room temperature drying type aqueous topcoat paint on the formed primer paint film; A repainting method for a multi-layer coating finish using the present aqueous solvent composition and a room temperature drying type aqueous paint on an old paint film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous primer paint and a room temperature drying type aqueous topcoat paint, and the method includes: applying the room temperature drying type aqueous primer paint to the old paint film on the substrate to form a primer paint film; and applying a diluted paint obtained by mixing the room temperature drying type aqueous topcoat paint and the aqueous solvent composition onto the formed primer paint film. The repainting method; A repainting method for a multi-layer coating finish using an aqueous solvent composition and a room temperature drying type aqueous paint on an old paint film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous primer paint and a room temperature drying type aqueous topcoat paint, and the method includes: applying a diluted paint obtained by mixing the room temperature drying type aqueous primer paint and the aqueous solvent composition to the old paint film on the substrate to form a primer paint film; and applying a diluted paint obtained by mixing the room temperature drying type aqueous topcoat paint and the aqueous solvent composition onto the formed primer paint film. The repainting method; Is also preferred.

[0065] In addition, the primer paint film may be formed by one type of primer paint or may be formed from two or more types of primer paints of different types. Similarly, the topcoat paint film may be formed by one type of topcoat paint or may be formed from two or more types of topcoat paints of different types. For example, when there are three or more coating steps such as applying a primer paint and then applying a topcoat paint thereon and then applying another topcoat paint thereon, it is also part of this embodiment.

[0066] When performing the multi-layer coating finish consisting of two or more coating steps, the interval time for applying the next paint after applying the primer paint is preferably 1 hour to 10 days at room temperature, preferably about 2 hours to 7 days.

[0067] Drying process The drying step is a step of drying each paint applied in the coating step to form a corresponding paint film. The drying time can be appropriately set by those skilled in the art according to the thickness of the target dried paint film.

[0068] Washing process In the present embodiment, the aqueous solvent composition can be used as a cleaning agent for removing the room temperature drying type aqueous paint.

[0069] The object for removing the room temperature drying type aqueous paint is mainly a painting tool, but the aqueous solvent composition can also be used for any member such as a place where the paint has spilled during painting work.

[0070] Some embodiments of the present invention include a cleaning method in which after repainting by applying a room temperature drying type aqueous paint to the surface of an old paint film on a substrate with a painting tool, the painting tool with the room temperature drying type aqueous paint adhering thereto is cleaned using the aqueous solvent composition.

[0071] The cleaning method is not particularly limited and can be carried out by appropriate means according to the type or state of the painting tool. For example, cleaning methods such as immersion cleaning, wiping cleaning, spray jet cleaning, ultrasonic cleaning, etc. can be mentioned. Note that wiping cleaning refers to cleaning in which the aqueous solvent composition is impregnated into fibers such as a cloth or a sponge and the painted portion of the painting tool is wiped. In particular, cleaning by immersion is preferred. When cleaning by immersion, the painting tool may be manually moved in a container containing the aqueous solvent composition to remove the adhering paint.

[0072] The cleaning time varies depending on the degree of dirt on the painting tool, but is, for example, from 30 seconds to 10 minutes, preferably about 1 minute to 5 minutes. The temperature of the aqueous solvent composition during removal is usually room temperature, but it may be heated as necessary to perform removal and cleaning.

[0073] Also, preliminary cleaning may be performed before cleaning the painting tool using the aqueous solvent composition. The preliminary cleaning is, for example, cleaning without using the above cleaning agent such as cleaning with tap water, and examples include immersion cleaning, running water cleaning, spray jet cleaning, wiping cleaning, ultrasonic cleaning, etc.

[0074] In some embodiments, it is possible to store the painting tools washed using an aqueous solvent composition by directly immersing them in the aqueous solvent composition. If painting tools such as brushes and rollers are left in the cleaning liquid for a long time, the cleaning liquid may spoil, and the handle or the roller pile part may spoil and have to be discarded. Since the aqueous solvent composition contains specific amounts of a specific organic solvent (A) and an amine compound (B), it has the property of being less likely to spoil even in summer. Therefore, the aqueous solvent composition is excellent in that it can store the painting tools while immersed, and can also extend the life of the painting tools compared to when other cleaning agents are used.

Example

[0075] The present invention will be described more specifically by the following examples, but the present invention is not limited to only these examples. In the following examples, "parts" and "%" mean "parts by mass" and "mass %", respectively.

[0076] Details of the test substrates and painting tools used in the examples are as follows. Test base material A test substrate was prepared by coating a steel plate with dimensions of 300 mm × 450 mm × 0.5 mm with an acrylic / melamine-based black paint using a bar coater so that the dry film thickness was 15 μm, and then heating it at 250°C for 1 minute to heat-cure it. The baked coating film formed by the heat-curable paint on the surface was regarded as an old coating film. Painting tool Brush: Chicken (manufactured by Otsuka Brush Manufacturing Co., Ltd., brush tip width 30 - 40 mm, brush length 38 mm wooden handle).

[0077] <Production of Aqueous Solvent Composition> Examples 1 - 20 and Comparative Examples 1 - 8 In a container, each component shown in Table 1 was blended and stirred and mixed to obtain aqueous solvent compositions (X-1) - (X-28).

[0078]

Table 1

[0079] (Note 1) Primol ASE60: Trade name, manufactured by The Dow Chemical Company, polyacrylic acid thickener, solid content 28% (Note 2) Laponite RDS: Trade name, manufactured by BYK, layered silicate rheology additive, solid content 10% (Note 3) Disparlon AQ600: Trade name, manufactured by Kusumoto Chemicals, polyamide-based aqueous thickener, Solid content 20%.

[0080] <Example of using the aqueous solvent composition as a treatment agent for old paint films, a diluent for aqueous undercoat paints, and a cleaner for diluting aqueous undercoats> Example 21 Assuming an outdoor outer wall, a far-infrared heater was brought close to the surface side of the test substrate created above so that the surface temperature of the test substrate was maintained at 50°C. In this state, the aqueous solvent composition (X-1) obtained in Example 1 was applied using a brush so as to penetrate the entire surface of the old paint film, and an old paint film treatment plate was obtained. In this example, a far-infrared heater is used, but this is to reproduce the natural drying state in summer in the experiment and is not intended for heat curing.

[0081] On the other hand, 5 parts of the aqueous solvent composition (X-1) was mixed with 100 parts of the aqueous undercoat paint A (Ales Dynamic Filler, trade name manufactured by Kansai Paint Co., Ltd., acrylic resin emulsion-based aqueous reaction-curing dual system filler JISA6909 architectural finish paint flexible type repair paint E), and stirred by hand holding a spatula to make it uniform, and a diluted aqueous undercoat paint was prepared.

[0082] While maintaining the temperature of the test substrate at 50°C, this diluted aqueous undercoat paint was applied to the old paint film surface treated with the aqueous solvent composition with a brush so that the dry film thickness was 30 μm, held for 3 hours, and then dried at room temperature for 7 days to create a repainted coating plate with the diluted aqueous undercoat paint applied on the old paint film surface. Thereafter, a coating workability evaluation test, an adhesion test, and a brush immersion putrefaction test were carried out. The brush cleanability was evaluated promptly after coating. The results are shown in Table 2.

[0083] Examples 22 to 40 and Comparative Examples 9 to 16 In Example 21 above, except that the aqueous solvent composition (X-1) used as the old coating film treatment agent, diluent, and cleaning agent was replaced with the aqueous solvent compositions (X-2) to (X-28) shown in Table 2, a repainted coated board was prepared and each evaluation test was carried out in the same procedure as in Example 21 above.

[0084]

Table 2

[0085] Example 41 In Example 21 above, except that 100 parts of the aqueous undercoat paint A (Ares Dynamic Filler) was replaced with 100 parts of the two-component aqueous undercoat paint B (Rubigoal, trade name of Kansai Paint Co., Ltd., epoxy resin emulsion and amino group-containing resin emulsion), an old coating film treatment board, a diluted aqueous undercoat paint, and a repainted coated board were prepared and each evaluation test was carried out in the same manner as in Example 21. In Example 21 above, except that 100 parts of the aqueous undercoat paint A (Ares Dynamic Filler) was replaced with 100 parts of the two-component aqueous undercoat paint B (Rubigoal, trade name of Kansai Paint Co., Ltd., epoxy resin emulsion and amino group-containing resin emulsion), an old coating film treatment board, a diluted aqueous undercoat paint, and a repainted coated board were prepared and each evaluation test was carried out in the same manner as in Example 21.

[0086] Examples 42 to 60 and Comparative Examples 17 to 24 In Example 21 above, except that the aqueous solvent composition (X-1) used as the old coating film treatment agent, diluent, and cleaning agent was replaced with the aqueous solvent compositions (X-2) to (X-28) shown in Table 3, a repainted coated board was prepared and each evaluation test was carried out in the same procedure as in Example 21 above.

[0087]

Table 3

[0088] <Applied Example 2 - Example of using an aqueous solvent composition as an old coating film treatment agent, a diluent for an aqueous undercoat paint, a diluent for an aqueous topcoat paint, and a cleaning agent for a diluted aqueous topcoat paint> Example 61 Aqueous topcoat paint C (Ares Silk Wall, trade name of Kansai Paint Co., Ltd., high weather resistance one-component aqueous a To 100 parts of a mat finish paint based on a curyl silicone resin (containing an acrylic resin emulsion), 5 parts of an aqueous solvent composition (X-1) was mixed, and stirred by hand with a spatula to make it uniform, thereby preparing a diluted aqueous topcoat paint.

[0089] Separately, a repainted panel was prepared in the same procedure as in Example 1. With the temperature of the test substrate being 50 °C, the diluted aqueous topcoat paint was applied to the undercoat film surface with a brush so that the dry film thickness would be 30 μm, held for 3 hours, and then dried at room temperature for 7 days, thereby preparing a repainted panel on which a diluted aqueous undercoat paint and a diluted aqueous topcoat paint were successively applied on an old coating film-treated panel treated with the aqueous solvent composition (X-1). Thereafter, an evaluation test on the application workability of the diluted aqueous topcoat paint, an adhesion test, a brush cleaning property of the brush with the diluted aqueous topcoat paint adhered thereto, and a brush standing and putrefaction test were carried out.

[0090] Examples 62 to 80 and Comparative Examples 25 to 32 In Example 61 above, except that the aqueous solvent composition (X-1) to be used was replaced with the aqueous solvent compositions (X-2) to (X-28) described in Table 4, an old coating film-treated panel, a diluted aqueous paint, a diluted aqueous topcoat paint, and a multilayer coated panel were prepared in the same procedure as in Example 61, and each evaluation test was carried out.

[0091] [Table 4]

[0092] Example 81 To 100 parts of an aqueous topcoat paint D (trade name, manufactured by Allesta Dynamite TOP Kansai Paint Co., Ltd., an aqueous reaction-curing type health high-rich acrylic silicone resin paint, containing an acrylic resin emulsion), 5 parts of an aqueous solvent composition (X-1) was mixed, and stirred by hand with a spatula to make it uniform, thereby preparing a diluted aqueous topcoat paint.

[0093] Separately, a primer coating film plate was prepared with an aqueous primer paint B (Rubigol) diluted with an aqueous solvent composition (X-1) prepared in the same procedure as in Example 41. With the temperature of the test substrate being 50 °C, this diluted aqueous topcoat paint was applied with a brush onto the primer coating film surface to a dry film thickness of 30 μm, held for 3 hours, and then dried at room temperature for 7 days to prepare a multilayer repainting coated plate with the diluted aqueous primer paint and the diluted aqueous topcoat paint successively applied onto the old coating film treated plate treated with the aqueous solvent composition (X-1). Thereafter, the coating workability, adhesion test, brush cleaning property, and brush standing putrefaction test of the diluted aqueous topcoat paint were carried out.

[0094] Examples 82 to 100 and Comparative Examples 33 to 40 In Example 81 above, except that the aqueous solvent composition (X-1) used was replaced with the aqueous solvent compositions (X-2) to (X-28) described in Table 5, an old coating film treated plate, a diluted aqueous primer paint, a diluted aqueous topcoat paint, and a multilayer repainting coated plate were prepared in the same procedure as in Example 81 above, and each evaluation test was carried out.

[0095]

Table 5

[0096] <Applied Example 3 - Example of using an aqueous solvent composition as an old coating film treating agent, a diluent for an aqueous primer paint, and a cleaning agent for an aqueous topcoat paint> Examples 101 to 104 A multilayer repainting coated plate was prepared according to the specifications described in Table 6 below, and thereafter, each evaluation test was carried out. The old coating film treatment, dilution method, coating method, etc. were carried out under the same conditions as in Example 61 or 81. However, in Applied Example 3, the aqueous topcoat paint was not diluted.

[0097]

Table 6

[0098] <Applied Example 4 - Example of using an aqueous solvent composition as an old coating film treating agent and a cleaning agent for an aqueous topcoat paint> Examples 105 to 108 Multilayer repainting coated plates were created according to the specifications shown in Table 7 below, and then each evaluation test was carried out. The old coating film treatment, dilution method, painting method, etc. were carried out under the same conditions as in Example 61 or 81. However, in Application Example 4, the aqueous topcoat paint and the aqueous undercoat paint were not diluted.

[0099]

Table 7

[0100] <Example of using an aqueous solvent composition as a treatment agent for the old coating film, a diluent for the aqueous topcoat paint, and a cleaning agent for diluting the aqueous topcoat paint> Examples 109 to 112 Multilayer repainting coated plates were created according to the specifications shown in Table 8 below, and then each evaluation test was carried out. The old coating film treatment, dilution method, painting method, etc. were carried out under the same conditions as in Example 61 or 81. However, in Application Example 5, the aqueous undercoat paint was not diluted.

[0101]

Table 8

[0102] <Example of not using an aqueous solvent composition as a treatment agent for the old coating film and using it as a diluent for the aqueous undercoat and / or aqueous topcoat> Examples 113 to 114 Single-layer repainting coated plates were created according to the specifications shown in Table 9 below, and then each evaluation test was carried out. In this example, the old coating film was not treated, and the dilution method, painting method, etc. were carried out under the same conditions as in Example 21 or 41.

[0103]

Table 9

[0104] Examples 115 to 120 A multi-layer repainted coating board was created according to the specifications described in Table 10 below, and then each evaluation test was carried out. In this example, the old coating film was not treated, and the dilution method, coating method, etc. were carried out under the same conditions as in Example 61 or 81.

[0105]

Table 10

[0106] <Evaluation Test> (1) Painting Workability The appearance of the repainted coating board coated with each water-based undercoat or water-based topcoat paint was observed and evaluated according to the following criteria.

[0107] (1-1) Smoothness ◎: The entire painted surface has a smooth feeling, and no mottled state is observed. 〇: The entire painted surface has a smooth feeling, but the mottled state is observed with an area ratio of less than 5%. △: The painted surface has a smooth feeling, but the mottled state is observed with an area ratio of 5% or more and less than 50%. ×: The painted surface has no smooth feeling, or the mottled state is observed with an area ratio of 50% or more, or bumps are observed. (1-2) Brush Marks ◎: No brush marks are observed at all. 〇: Brush marks are observed with an area ratio of less than 5%. △: Brush marks are observed with an area ratio of 5% or more and less than 50%, or slight bleeding through of the lower layer is observed in the valleys of the brush marks. ×: Brush marks are observed with an area ratio of 50% or more, or clear bleeding through of the lower layer is observed in the valleys of the brush marks.

[0108] (2) Adhesion (in the case of a single layer of water-based undercoat paint) For the coating board coated with each diluted water-based undercoat paint, a cut was made with a cutter to form 100 squares with a width of 1 mm. Subsequently, after attaching an adhesive tape to the test piece, it was pulled in a direction diagonally upward at 45 degrees with respect to the grid, and the number of squares of the remaining undercoat film was counted, and this remaining number was used as an index of adhesion. ◎: The remaining number of squares is 100 ○: The remaining number of squares is 90 or more and 99 or less △: The remaining number of squares is 80 or more and 89 or less. ×: The remaining number of squares is 79 or less.

[0109] (3) Adhesion (in the case of a double layer of water-based primer paint and water-based topcoat paint) For each painted board coated with diluted water-based primer paint and diluted water-based topcoat paint, a 100-square grid of scratches with a width of 1 mm was made with a cutter. Subsequently, after attaching an adhesive tape to the test piece, it was pulled in a direction 45 degrees obliquely upward with respect to the base grid, and the number of remaining squares of the topcoat film was counted, and this remaining number was used as an index of adhesion. ◎: The remaining number of squares is 100 ○: The remaining number of squares is 90 or more and 99 or less △: The remaining number of squares is 80 or more and 89 or less. ×: The remaining number of squares is 79 or less.

[0110] (4) Washability Approximately 200 ml of each aqueous solvent composition was placed as a cleaning solution in a mayonnaise bottle with a capacity of 450 ml. After each painted board was made, it was scrubbed 50 times so that the entire bristle part of the brush was immersed in the cleaning solution, and then the brush was pulled up and the bristle part was observed and evaluated according to the following criteria. ◎: No paint remains on the surface and inside of the bristle part 〇: No paint remains on the surface of the bristle part, but a very small amount of paint remains deep inside △: A small amount of paint remains on the surface and inside of the bristle part. ×: Paint remains significantly on the surface and inside of the bristle part.

[0111] (5) Bristle immersion putrefaction test After the above washability test was completed, assuming summer, the brush was left immersed in the cleaning solution for 2 weeks as it was in an atmosphere of 30 °C, and then the cleaning solution in the mayonnaise bottle and the state of the handle part of the brush were observed. ◎: No mold is observed in the cleaning solution and the handle part of the brush 〇: Slight mold is observed in the cleaning solution, but no mold is observed on the handle part of the brush △: Slight mold is observed in the cleaning solution and on the handle part of the brush ×: Mold is significantly observed in the cleaning solution and on the handle part of the brush

Claims

1. A multi-purpose aqueous solvent composition used for repainting by applying a room-temperature drying type aqueous paint onto the surface of an old paint film on a substrate, comprising: at least one organic solvent (A) selected from the group consisting of an alcohol-based organic solvent, an ether-based organic solvent, a ketone-based organic solvent, and an ester-based organic solvent, an amine compound (B), and water, wherein the content of the organic solvent (A) is 1 to 50% by mass and the content of the amine compound (B) is 0.05 to 10% by mass based on the total amount of the aqueous solvent composition, and the solid content concentration of the aqueous solvent composition is 0% by mass or less than 0.5% by mass.

2. The aqueous solvent composition according to Claim 1, which is a dual-purpose type that can be used in any two or more of the old paint film treatment step, paint preparation step, and cleaning step in the repainting.

3. A repainting method comprising a step of applying the aqueous solvent composition according to Claim 1 or 2 onto an old paint film on a substrate and allowing the aqueous solvent composition to penetrate into the old paint film.

4. A repainting method comprising a step of applying the aqueous solvent composition according to Claim 1 or 2 onto an old paint film on a metal substrate and allowing the aqueous solvent composition to penetrate into the old paint film.

5. A repainting method comprising a step of applying the aqueous solvent composition according to Claim 1 or 2 onto an old paint film formed by a heat-curable paint on a metal substrate and allowing the aqueous solvent composition to penetrate into the old paint film.

6. A repainting method comprising a step of applying a diluted paint obtained by mixing a room-temperature drying type aqueous paint and the aqueous solvent composition according to Claim 1 or 2 onto an old paint film on a substrate.

7. A single-layer finishing repainting method using an aqueous solvent composition and a room-temperature drying type aqueous paint for an old paint film on a substrate, comprising: applying the aqueous solvent composition onto the old paint film on the substrate and allowing the aqueous solvent composition to penetrate into the old paint film, and applying a room-temperature drying type aqueous paint onto the old paint film into which the aqueous solvent composition has penetrated.

8. A single-layer finishing repainting method using an aqueous solvent composition and a room-temperature drying type aqueous paint for an old paint film on a substrate, comprising: applying the aqueous solvent composition onto the old paint film on the substrate and allowing the aqueous solvent composition to penetrate into the old paint film, and applying a diluted paint obtained by mixing a room-temperature drying type aqueous paint and the present aqueous solvent composition onto the old paint film into which the aqueous solvent composition has penetrated.

9. ​ A repainting method of single-layer finishing using an aqueous solvent composition and a room-temperature drying type aqueous paint for an old paint film on a substrate, comprising: A repainting method comprising applying a diluted paint obtained by mixing a room-temperature drying type aqueous paint and an aqueous solvent composition to an old paint film on a substrate.

10. A repainting method of multi-layer coating finish using the aqueous solvent composition and the room-temperature drying type aqueous paint according to claim 1 or 2 for an old paint film on a substrate, wherein the room-temperature drying type aqueous paint always Includes a room-temperature drying type aqueous primer paint and a room-temperature drying type aqueous topcoat paint, and the method comprises: Applying the aqueous solvent composition according to claim 1 or 2 to the old paint film on the substrate and allowing the aqueous solvent composition according to claim 1 or 2 to penetrate into the old paint film. Applying a room-temperature drying type aqueous primer paint to the old paint film penetrated with the aqueous solvent composition to form a primer paint film, and Applying a room-temperature drying type aqueous topcoat paint onto the formed primer paint film. A repainting method comprising:

11. A repainting method of multi-layer coating finish using the aqueous solvent composition and the room-temperature drying type aqueous paint according to claim 1 or 2 for an old paint film on a substrate, wherein the room-temperature drying type aqueous paint includes a room-temperature drying type aqueous primer paint and a room-temperature drying type aqueous topcoat paint, and the method comprises: Applying the aqueous solvent composition according to claim 1 or 2 to the old paint film on the substrate and allowing the aqueous solvent composition according to claim 1 or 2 to penetrate into the old paint film. Applying a room-temperature drying type aqueous primer paint to the old paint film penetrated with the aqueous solvent composition to form a primer paint film, and Applying a diluted paint obtained by mixing a room-temperature drying type aqueous topcoat paint and the aqueous solvent composition according to claim 1 or 2 onto the formed primer paint film. A repainting method comprising:

12. A repainting method of multi-layer coating finish using the aqueous solvent composition and the room-temperature drying type aqueous paint according to claim 1 or 2 for an old paint film on a substrate, wherein the room-temperature drying type aqueous paint includes a room-temperature drying type aqueous primer paint and a room-temperature drying type aqueous topcoat paint, and the method comprises: Applying the aqueous solvent composition according to claim 1 or 2 to the old paint film on the substrate and allowing the aqueous solvent composition according to claim 1 or 2 to penetrate into the old paint film. Applying a diluted paint obtained by mixing a room-temperature drying type aqueous primer paint and the aqueous solvent composition according to claim 1 or 2 to the old paint film penetrated with the aqueous solvent composition to form a primer paint film, and Applying a room-temperature drying type aqueous topcoat paint onto the formed primer paint film. A repainting method including

13. A repainting method for a multi-layer coating finish using the aqueous solvent composition according to claim 1 or 2 and a room temperature drying type aqueous paint on an old coating film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous undercoat paint and a room temperature drying type aqueous topcoat paint, and the method comprises: Applying the aqueous solvent composition according to claim 1 or 2 to the old coating film on the substrate and allowing the aqueous solvent composition according to claim 1 or 2 to penetrate into the old coating film; Applying a diluted paint obtained by mixing a room temperature drying type aqueous undercoat paint and the aqueous solvent composition according to claim 1 or 2 to the old coating film into which the aqueous solvent composition has penetrated to form an undercoat film; and Applying a diluted paint obtained by mixing a room temperature drying type aqueous topcoat paint and the aqueous solvent composition according to claim 1 or 2 to the formed undercoat film. A repainting method including

14. A repainting method for a multi-layer coating finish using the aqueous solvent composition according to claim 1 or 2 and a room temperature drying type aqueous paint on an old coating film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous undercoat paint and a room temperature drying type aqueous topcoat paint, and the method comprises: Applying a diluted paint obtained by mixing a room temperature drying type aqueous undercoat paint and the aqueous solvent composition according to claim 1 or 2 to the old coating film on the substrate to form an undercoat film; and Applying a room temperature drying type aqueous topcoat paint to the formed undercoat film. A repainting method including

15. A repainting method for a multi-layer coating finish using the aqueous solvent composition according to claim 1 or 2 and a room temperature drying type aqueous paint on an old coating film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous undercoat paint and a room temperature drying type aqueous topcoat paint, and the method comprises: Applying a room temperature drying type aqueous undercoat paint to the old coating film on the substrate to form an undercoat film; and Applying a diluted paint obtained by mixing a room temperature drying type aqueous topcoat paint and the aqueous solvent composition according to claim 1 or 2 to the formed undercoat film. A repainting method including

16. A repainting method for a multi-layer coating finish using the aqueous solvent composition according to claim 1 or 2 and a room temperature drying type aqueous paint on an old coating film on a substrate, wherein the room temperature drying type aqueous paint includes a room temperature drying type aqueous undercoat paint and a room temperature drying type aqueous topcoat paint, and the method comprises: Applying a diluted paint, which is obtained by mixing a room temperature-drying type water-based undercoat paint and the water-based solvent composition according to claim 1 or 2, onto an old paint film on a substrate to form an undercoat paint film, and applying a diluted paint, which is obtained by mixing a room temperature-drying type water-based topcoat paint and the water-based solvent composition according to claim 1 or 2, onto the formed undercoat paint film. A repainting method comprising the above.

17. A cleaning method comprising cleaning a painting tool having a room temperature-drying type water-based paint adhered thereto, after performing repainting by applying a room temperature-drying type water-based paint onto an old paint film surface on a substrate with the painting tool, using the water-based solvent composition according to claim 1 or 2.

18. A storage method for a painting tool, comprising cleaning a painting tool having a room temperature-drying type water-based paint adhered thereto, after performing repainting by applying a room temperature-drying type water-based paint onto an old paint film surface on a substrate with the painting tool, using the water-based solvent composition according to claim 1 or 2, and immersing the painting tool in the water-based solvent composition according to claim 1 or 2.

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