Coating material composition, coating film, and article

Abstract

The present invention addresses the problem of providing a coating material which does not undergo phase separation during storage even if the content of a hydrophobic solvent is zero or low, and which yields a coating film that exhibits water-resistant adhesive properties and exhibits good water-resistant swelling resistance and sagging resistance.　The present invention is a coating material composition that contains a coating film-forming resin and a viscous agent. The viscous agent contains at least one type selected from the group consisting of a carboxyvinyl polymer and diutan gum. The coating material composition has a steady value η1 of a prescribed viscosity of 0.10-0.90 Pa·s, has a steady value η2 of a prescribed viscosity of 0.02-0.09 Pa·s, and satisfies a prescribed relationship between creep compliance value and time.

Description

Paint compositions, coatings, and articles

[0001] This invention relates to paint compositions, coatings, and articles.

[0002] In recent years, due to VOC regulations for paints (for example, China's GB standard), there has been a need to reduce the hydrophobic solvent content in paints (for example, Patent Document 1).

[0003] Japanese Patent Publication No. 2024-141943

[0004] However, simply changing the solvent in the paint from a hydrophobic solvent to an aqueous solvent can lead to phase separation during paint storage, and a decrease in the water-resistant adhesion, water-blistering resistance, and sagging resistance of the paint film.

[0005] Therefore, it is necessary to develop a paint that does not undergo phase separation during storage, even with zero or low hydrophobic solvent content, and that exhibits good water-resistant adhesion, water-resistant blistering, and sagging resistance of the paint film.

[0006] Therefore, the present invention aims to provide a paint that does not undergo phase separation during storage, even if the hydrophobic solvent content is zero or small, and that exhibits good water-resistant adhesion, water-resistant blistering, and sagging resistance of the paint film.

[0007] The paint composition according to the present invention is a paint composition comprising a film-forming resin and a viscous agent, wherein the viscous agent comprises at least one selected from the group consisting of carboxyvinyl polymer and dieutan gum, and the paint composition is subjected to a temperature of 23°C and a shear rate of 10 s. －１ The steady-state viscosity η1 measured during steady-state flow measurement of shear deformation is 0.10 to 0.90 Pa·s, and the temperature is 23°C and the shear rate is 1,000 s. －１ The steady-state viscosity η² in steady-state flow measurement of shear deformation is 0.02 to 0.09 Pa·s, and creep measurement is performed on the paint composition under conditions of 23°C and stress of 1 Pa, where t is time (s) and J(t) is the creep compliance value (Pa). －１ When dJ(t) / dt becomes constant, the value of dJ(t) / dt is 1.8 × 10⁻¹⁰. －１The paint composition is as follows. As a result, even if the hydrophobic solvent content is zero or small, phase separation does not occur during storage of the paint, and the water-resistant adhesion, water-resistant blistering, and sagging of the paint film are good.

[0008] In one embodiment of the paint composition according to the present invention, the content of the viscous agent is 0.01 to 0.7% by mass of the total mass of the paint composition.

[0009] In one embodiment of the coating composition according to the present invention, the non-volatile content (NV) of the coating composition is 1 to 80% by mass of the total mass of the coating composition.

[0010] In one embodiment of the paint composition according to the present invention, the paint composition is an aqueous paint composition.

[0011] In one embodiment of the paint composition according to the present invention, the paint composition further comprises an alkali-swelling type viscous agent.

[0012] The coating film according to the present invention is a coating film using any of the above-mentioned coating compositions.

[0013] The article according to the present invention has the above-mentioned coating film.

[0014] According to the present invention, even if the hydrophobic solvent content is zero or small, phase separation does not occur during storage of the paint, and a paint with good water resistance, adhesion, water resistance, blister resistance, and sagging resistance of the paint film can be provided.

[0015] The embodiments of the present invention will be described below. These descriptions are for illustrative purposes only and do not limit the present invention in any way.

[0016] In the present invention, two or more embodiments can be arbitrarily combined.

[0017] Unless otherwise specified, the materials, components, compounds, resins, curing agents, viscous agents, and solvents described herein may be used individually or in combination of two or more types.

[0018] In the present invention, paints and paint compositions can be used interchangeably.

[0019] In the present invention, the term "solid content" is a concept that includes solid content and non-volatile content. Also, the solid content may be referred to as NV.

[0020] In this specification, unless otherwise specified, numerical ranges are intended to include the upper and lower limit values of the range. For example, 0.10 to 0.90 Pa·s means 0.10 Pa·s or more and 0.90 Pa·s or less.

[0021] In the present invention, "even if the content of the hydrophobic solvent is zero or at least small" means that it is applicable at least when the content of the hydrophobic solvent is small (for example, 15% by mass or less based on the total mass of the coating composition), and it is not intended to exclude weak solvent-based coatings and strong solvent-based coatings containing hydrophobic solvents.

[0022] In the present invention, at least one tackifier selected from the group consisting of carboxyvinyl polymer and diutan gum may be referred to as the first tackifier.

[0023] In the present invention, an alkali swelling type tackifier may be referred to as the second tackifier.

[0024] In the present invention, for the coating composition at 23°C and a shear rate of 10 s －１ the steady value η1 of the viscosity in the steady flow measurement of shear deformation is determined by the method described in the examples.

[0025] In the present invention, for the coating composition at 23°C and a shear rate of 1000 s －１ the steady value η2 of the viscosity in the steady flow measurement of shear deformation is determined by the method described in the examples.

[0026] In the present invention, a creep measurement is performed on the coating composition under the conditions of 23°C and a stress of 1 Pa. When t is the time (s) and J(t) is the value of the creep compliance (Pa －１ ), the value of dJ(t) / dt when dJ(t) / dt becomes constant is determined by the method described in the examples. Also, the value of dJ(t) / dt when it becomes constant may be referred to as CCS.

[0027] (Paint Composition) The paint composition according to the present invention is a paint composition containing a film-forming resin and a thickener, wherein the thickener contains at least one selected from the group consisting of carboxyvinyl polymer and diutan gum, and the paint composition has a steady value η1 of viscosity in the steady flow measurement of shear deformation at 23°C and a shear rate of 10 s －１ of 0.10 to 0.90 Pa·s, and a steady value η2 of viscosity in the steady flow measurement of shear deformation at 23°C and a shear rate of 1,000 s －１ of 0.02 to 0.09 Pa·s. A creep measurement is performed on the paint composition under the conditions of 23°C and a stress of 1 Pa. When t is the time (s) and J(t) is the value of creep compliance (Pa －１ ), the value of dJ(t) / dt when dJ(t) / dt becomes constant is 1.8×10 －１ or less. It is a paint composition.

[0028] In conventional paint compositions, viscosity is developed by the interaction between a hydrophobic solvent and a thickener (viscosity modifier) to increase the viscosity, thereby imparting sag resistance to the paint composition. However, simply changing the solvent of the paint from a hydrophobic solvent to an aqueous solvent is considered to reduce or lose the interaction between the hydrophobic solvent and the thickener, resulting in insufficient viscosity development. And due to insufficient viscosity, the paint sags during the drying of the painted film after painting, reducing the smoothness of the painted film. In thin parts of the painted film, water resistance decreases, water penetrates into the painted film or the lower surface of the painted film, adhesion decreases, and swelling of the painted film is considered to occur.

[0029] In contrast, the present inventors have used a thickener selected from the group consisting of carboxyvinyl polymer and diutan gum, and by setting the steady values η1 and η2 of viscosity and CCS within a predetermined range, phase separation does not occur during the storage of the paint, and the water-tight adhesion of the painted film, the water resistance and swelling resistance of the painted film, and the sag resistance are improved.

[0030] Hereinafter, the film-forming resin and the specific thickener, which are essential components of the paint composition of the present invention, will be described.

[0031] • Film-forming resin: In the paint composition of the present invention, the film-forming resin is not particularly limited, and any film-forming resin used in known paint compositions can be used. Examples of film-forming resins include acrylic resins, polyester resins, alkyd resins, fluororesins, epoxy resins, polyurethane resins, polyether resins, polyolefin resins, and melamine resins. Furthermore, as the resin component, polymer compounds containing or composed of inorganic components, such as silicone resins and alkoxysilane condensates, can also be used.

[0032] The molecular weight of the film-forming resin is not particularly limited and can be adjusted as appropriate. The number-average molecular weight (Mn) of the film-forming resin is, for example, 5,000 to 30,000.

[0033] The film-forming resin may be an organic solvent type, a water-based type (water-soluble, water-dispersible, or emulsion), or a non-water-dispersible type.

[0034] The content of the film-forming resin is not particularly limited and can be adjusted as appropriate. In one embodiment, the solid content of the film-forming resin is 30 to 95% by mass relative to the total mass of solid content of the paint composition.

[0035] • Viscosity Agent The paint composition of the present invention uses a viscosity agent comprising at least one selected from the group consisting of carboxyvinyl polymer and dieutan gum. As a result, viscosity is imparted with a small amount, resulting in good water resistance, adhesion, water resistance, blister resistance, and sagging resistance of the coating film. In the present invention, if the first viscosity agent (carboxyvinyl polymer or dieutan gum) also corresponds to the alkali-swelling type viscosity agent (second viscosity agent) described later, that viscosity agent is treated as the first viscosity agent, not the alkali-swelling type viscosity agent.

[0036] Examples of carboxyvinyl polymers include polymers of acrylic acid (water-soluble polymers) that are denoted as carbomers in INCI. The carboxyvinyl polymer is not particularly limited, and known carboxyvinyl polymers can be appropriately selected and used.

[0037] Commercially available carboxyvinyl polymers may also be used. Examples of commercially available carboxyvinyl polymers include "Carbopol® 940," "Carbopol 941," "Carbopol 980," and "Carbopol 981" from Lubrizol Advanced Materials; "Hibiscus Wako® 103," "Hibiscus Wako® 104," "Hibiscus Wako® 105," and "Hibiscus Wako® 105MD" from Fujifilm Wako Pure Chemical Industries; "Acpec® HV-501," "Acpec HV-504," "Acpec HV-505," "Acpec HV-505E," "Acpec HV-801EG," and "Acpec HV-805EG" from Sumitomo Seika Co., Ltd.; and "Syntalen K" and "Syntalen L" from 3V Sigma.

[0038] The dieutan gum is not particularly limited, and any known dieutan gum can be appropriately selected and used. In one embodiment, the dieutan gum consists of a repeating structure of units in which a main chain of glucose, glucuronic acid, glucose, and rhamnose is attached to two rhamnose side chains.

[0039] Commercially available diutan gum may be used. Examples of commercially available diutan gum include the KELCO-VIS® series, Geovis series, KELCO-CARE® series, and KELCO-CRETE® series manufactured by CPKelco.

[0040] The amount of the first viscous agent in the paint composition is not particularly limited as long as it satisfies the range of predetermined viscosity steady values ​​η1 and η2 and CCS of the present invention. In one embodiment, the content of the first viscous agent is 0.01 to 0.7% by mass with respect to the total mass of the paint composition. In another embodiment, the content of the first viscous agent is 0.01% by mass or more, 0.05% by mass or more, 0.10% by mass or more, 0.15% by mass or more, 0.20% by mass or more, 0.25% by mass or more, 0.20% by mass or more, 0.25% by mass or more, 0.30% by mass or more, 0.35% by mass or more, 0.40% by mass or more, 0.45% by mass or more, 0.50% by mass or more, 0.55% by mass or more, 0.60% by mass or more, or 0.65% by mass or more, with respect to the total mass of the paint composition. In yet another embodiment, the content of the first viscous agent is 0.70% by mass or less, 0.65% by mass or less, 0.60% by mass or less, 0.55% by mass or less, 0.50% by mass or less, 0.45% by mass or less, 0.40% by mass or less, 0.35% by mass or less, 0.30% by mass or less, 0.25% by mass or less, 0.20% by mass or less, 0.15% by mass or less, 0.10% by mass or less, or 0.05% by mass or less, based on the total mass of the paint composition.

[0041] In the paint composition, the content of the first viscous agent may be, for example, 0.1 to 5.0 parts by mass per 100 parts by mass of the total mass of the solid content of the film-forming resin of the paint composition.

[0042] In a paint composition, when a first viscous agent and other viscous agents are used in combination as a viscous agent, the amount of solids of the first viscous agent relative to the total mass of solids of the viscous agents may be, for example, 6 to 90% by mass (preferably 15 to 75% by mass).

[0043] - The paint composition may optionally contain other components besides the film-forming resin and the first viscosity agent. Examples of other components include alkali-swelling viscosity agents (second viscosity agent), curing agents, gloss agents, dispersants, curing catalysts, other viscosity agents, film-forming aids, ultraviolet absorbers, light stabilizers, antioxidants, defoamers, surface modifiers, pinhole inhibitors, rust inhibitors, pigments, etc.

[0044] Alkali-swelling viscosity agents are acrylic polymers having acidic groups such as carboxyl groups, which swell when neutralized with alkaline substances (such as alkali metal hydroxides, alkali metal salts of carbonate, alkali metal salts of bicarbonate, ammonia, monoalkanolamines, dialkanolamines, or trialkanolamines), thereby imparting viscosity to paint compositions. Alkali-swelling viscosity agents are usually insoluble in water under non-alkaline conditions.

[0045] Examples of alkali-swelling type viscosity agents include polycarboxylic acid-based viscosity agents, polysulfonic acid-based viscosity agents, and polyphosphate-based viscosity agents.

[0046] Examples of commercially available alkaline swelling-type viscosity agents include the SN Thickener series from Sunopco, such as SN Thickener 615, 630, 636, and 640; the Primal series from Dow-Toray, such as Primal ASE-60; and BASF's "Viscalex HV30."

[0047] In one embodiment, the paint composition comprises at least a first viscous agent and a second viscous agent. In another embodiment, the paint composition comprises at least the first viscous agent but does not contain the second viscous agent. In yet another embodiment, the paint composition comprises only the first viscous agent as the viscous agent.

[0048] In the present invention, at least one selected from the group consisting of urethane-associated viscous agents, cellulose-based viscous agents, amide-based viscous agents, inorganic layered compound-based viscous agents, and aminoplast-based viscous agents may be used as the third viscous agent.

[0049] Examples of urethane-associated viscous agents include urethane-modified polyether-type viscous agents.

[0050] Examples of commercially available urethane-associated viscosities include the Adekanol® UH series, such as Adekanol® UH-140S, 420, 450, 526, 540, and 550, manufactured by ADEKA Corporation; and SN Thickener 665T, manufactured by Sunopco Corporation.

[0051] Examples of cellulose-based viscous agents include crystalline cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose.

[0052] Examples of commercially available cellulose-based viscosity agents include the Ceolus® series, such as the Ceolus® RC series manufactured by Asahi Kasei Corporation, and the Celosize® series, such as the Celosize QP 4400 and 52000H manufactured by Dow Chemical Corporation.

[0053] Examples of amide-based viscous agents include fatty acid amides, polyamides, acrylamides, long-chain polyaminoamides, aminoamides, and their salts (e.g., phosphates).

[0054] Examples of inorganic layered compound-based viscous agents include layered compounds such as montmorillonite, bentonite, and clay.

[0055] Examples of aminoplast-based viscosity modifiers include hydrophobic modified ethoxylate aminoplast-based association-type viscosity modifiers.

[0056] The amount of alkali-swelling type viscosity agent (second viscosity agent) in the paint composition is not particularly limited as long as it satisfies the range of predetermined viscosity steady values ​​η1 and η2 and CCS of the present invention. In one embodiment, the content of the second viscosity agent is 50 to 500 parts by mass per 100 parts by mass of the first viscosity agent, in terms of solid content or active ingredients. In one embodiment, the content of the second viscosity agent is 50 parts by mass or more, 100 parts by mass or more, 150 parts by mass or more, 200 parts by mass or more, 250 parts by mass or more, 300 parts by mass or more, 350 parts by mass or more, 400 parts by mass or more, or 450 parts by mass or more per 100 parts by mass of the first viscosity agent, in terms of solid content or active ingredients. In another embodiment, the content of the second viscous agent is 500 parts by mass or less, 450 parts by mass or less, 400 parts by mass or less, 350 parts by mass or less, 300 parts by mass or less, 250 parts by mass or less, 200 parts by mass or less, 150 parts by mass or less, or 100 parts by mass or less, per 100 parts by mass of the first viscous agent.

[0057] The paint composition of the present invention may contain a curing agent. The curing agent is not particularly limited, and known curing agents can be appropriately selected and used. Examples include amine-based curing agents, carbodiimide-based curing agents, epoxy-based curing agents, isocyanate-based curing agents, melamine-based curing agents, and the like.

[0058] • Luminous material: The luminous material is not particularly limited, and known luminous materials can be used. Examples of luminous materials include mica pigments such as interference mica, white mica, and colored mica; graphite pigments; glass flake pigments; and metallic pigments such as aluminum, copper, zinc, iron, nickel, tin, aluminum oxide, chromium oxide, and alloys containing these.

[0059] The paint composition of the present invention may be either an aqueous paint composition or a solvent-based paint composition. In one embodiment, the paint composition of the present invention is an aqueous paint composition. In another embodiment, it is a paint composition that satisfies the provisions of JIS A 6909.

[0060] In this invention, a paint composition in which the most abundant dispersion medium is water is called an aqueous paint composition. In this invention, a paint composition in which the most abundant dispersion medium is an organic solvent is called a solvent-based paint composition.

[0061] When using water, conventionally known types of water can be appropriately selected and used. Examples of water include tap water, distilled water, deionized water, and purified water.

[0062] When water is used, the water content of the paint composition may be adjusted as appropriate. For example, the water content of the paint composition is 20 to 80% by mass based on 100% by mass of the paint composition. In one embodiment of the paint composition of the present invention, the water content is 20% or more by mass, 30% or more by mass, 40% or more by mass, 50% or more by mass, 60% or more by mass, 70% or more by mass, or 80% or more by mass, based on 100% by mass of the paint composition. In one embodiment of the paint composition of the present invention, the water content is 80% or less by mass, 70% or less by mass, 60% or less by mass, 50% or less by mass, 40% or less by mass, 30% or less by mass, or 20% or less by mass, based on 100% by mass of the paint composition.

[0063] • Organic solvents: When using organic solvents, conventionally known organic solvents for paint compositions can be appropriately selected and used. Examples of organic solvents include alcohols such as methanol, ethanol, 2-propanol, and 1-butanol. In addition, solvents described in Japanese Patent Publication No. 2022-044364 can also be used.

[0064] The coating composition of the present invention may be room-temperature drying type or heat-curing type. In one embodiment, the coating composition of the present invention is heat-curing type.

[0065] The paint composition of the present invention may be a one-component type or a two-component type.

[0066] If the paint composition is an aqueous paint composition, the content of the organic solvent can be adjusted as appropriate. For example, it is 0 to 15% by mass, preferably 0 to 10% by mass, based on 100% by mass of the paint composition.

[0067] This invention is based on a temperature of 23°C and a shear rate of 10s. －１The steady-state viscosity η1 measured during steady-state flow measurement of shear deformation is 0.10 to 0.90 Pa·s. Having η1 within this range prevents phase separation during paint storage, resulting in a uniform coating and good water resistance, adhesion, and blister resistance. Furthermore, having η1 within this range allows for reduced paint scattering and shorter transfer times when transferring paint to containers such as tanks. In one embodiment, η1 is 0.10 Pa·s or higher, 0.15 Pa·s or higher, 0.20 Pa·s or higher, 0.25 Pa·s or higher, 0.30 Pa·s or higher, 0.35 Pa·s or higher, 0.40 Pa·s or higher, 0.45 Pa·s or higher, 0.50 Pa·s or higher, 0.55 Pa·s or higher, 0.60 Pa·s or higher, 0.65 Pa·s or higher, 0.70 Pa·s or higher, 0.75 Pa·s or higher, 0.80 Pa·s or higher, or 0.85 Pa·s or higher. In another embodiment, η1 is 0.90 Pa·s or less, 0.85 Pa·s or less, 0.80 Pa·s or less, 0.75 Pa·s or less, 0.70 Pa·s or less, 0.65 Pa·s or less, 0.60 Pa·s or less, 0.55 Pa·s or less, 0.50 Pa·s or less, 0.45 Pa·s or less, 0.40 Pa·s or less, 0.35 Pa·s or less, 0.30 Pa·s or less, 0.25 Pa·s or less, 0.20 Pa·s or less, or 0.15 Pa·s or less.

[0068] The present invention is based on a temperature of 23°C and a shear rate of 1,000 s. －１ The steady-state viscosity η2 measured during steady-state flow measurement of shear deformation is 0.02 to 0.09 Pa·s. Having η2 within this range results in good paint discharge performance. In particular, it is suitable for discharge using paint jets, and it can suppress paint splatter and leakage into the surroundings when dispensing with a dispenser or paint jet. In one embodiment, η2 is 0.02 Pa·s or more, 0.03 Pa·s or more, 0.04 Pa·s or more, 0.05 Pa·s or more, 0.06 Pa·s or more, 0.07 Pa·s or more, or 0.08 Pa·s or more. In another embodiment, η2 is 0.09 Pa·s or less, 0.08 Pa·s or less, 0.07 Pa·s or less, 0.06 Pa·s or less, 0.05 Pa·s or less, 0.04 Pa·s or less, or 0.03 Pa·s or less.

[0069] In this invention, we focused on the relationship between the microscopic stress on the paint due to gravity and the sagging of the paint, and used CCS to quantify the amount of strain in the paint when a constant stress is applied. The CCS of this invention is 1.8 × 10 －１ The following applies: CCS is 1.8 × 10 －１ The following conditions result in good paint sagging resistance. In one embodiment, the CCS is 1.8 × 10 －１ Below, 1.5 x 10 －１ Below, 1.0 × 10 －１ Below, 0.5 × 10 －１ Below, 0.1 × 10 －１ Below, 1.0 × 10 －３ Below, 1.0 × 10 －４ Below, 8.0 x 10 －５ Below, 7.0 x 10 －５ Below, 6.0 x 10 －５ The following or 5.0 x 10 －５ The following is the case. In another embodiment, the CCS is 4.0 × 10 －５ The above is 5.0 x 10 －５ The above is 6.0 x 10 －５ The above is 7.0 x 10 －５ The above is 8.0 x 10 －５ The above is 9.0 x 10 －５ The above is 1.0 x 10 －４ The above is 1.0 x 10 －３ The above is 1.0 x 10 －２ The above is 5.0 x 10 －２ The above is 1.0 x 10 －１ The above or 1.5 x 10 －１ That's all.

[0070] • Method for adjusting the parameters of the present invention The following describes examples of methods for adjusting η1, η2 and CCS.

[0071] This invention is based on a temperature of 23°C and a shear rate of 10s. －１The steady-state viscosity η1 measured during steady-state flow measurement of shear deformation is 0.10 to 0.90 Pa·s. When the solid content (NV) of the paint composition is similar, increasing the amount of the first viscous agent tends to increase both η1 and η2 (1). Also, when the solid content (NV) of the paint composition is similar, increasing the amount of the first viscous agent tends to decrease the CCS (2). In tendency (1), the tendency for η1 to increase is more pronounced than the tendency for η2 to increase. Furthermore, when the solid content (NV) of the paint composition is similar, tendency (1) is more pronounced than tendency (2). On the other hand, when the amount of the first viscous agent is similar, lowering the solid content (NV) of the paint composition tends to decrease both η1 and η2 (3). Furthermore, when the amount of the first viscous agent is similar, increasing the solids content (NV) of the paint composition tends to reduce the CCS (4).

[0072] The non-volatile content (NV) in the paint composition of the present invention can be adjusted as appropriate and is not particularly limited. For example, the NV in the paint composition is 1 to 80% by mass with respect to the total mass of the paint composition. In one embodiment, the NV in the paint composition is 1% or more by mass, 3% or more by mass, 5% or more by mass, 10% or more by mass, 15% or more by mass, 20% or more by mass, 25% or more by mass, 30% or more by mass, 35% or more by mass, 40% or more by mass, 45% or more by mass, 50% or more by mass, 55% or more by mass, 60% or more by mass, 65% or more by mass, 70% or more by mass, or 75% or more by mass, with respect to the total mass of the paint composition. In another embodiment, NV in the paint composition is 80% by mass or less, 75% by mass or less, 70% by mass or less, 65% by mass or less, 60% by mass or less, 55% by mass or less, 50% by mass or less, 45% by mass or less, 40% by mass or less, 35% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, based on the total mass of the paint composition. In yet another embodiment, NV in the paint composition is 3 to 30% by mass, based on the total mass of the paint composition.

[0073] • Method for preparing the paint composition The method for preparing the paint composition is not particularly limited, and known methods for preparing paint compositions can be used. For example, it can be prepared by mixing essential components such as a film-forming resin and a viscous agent, and other components as needed. Dispersers, ball mills, roll mills, planetary mixers, etc., can be used for mixing the components.

[0074] • Uses of the paint composition The uses of the paint composition of the present invention are not particularly limited and can be used for the same purposes as known paint compositions. Examples of uses of the paint composition include spray painting, electrostatic painting, liquid film discharge painting, liquid column discharge painting, or liquid droplet discharge painting. It can also be used for painting vehicles, buildings, home appliances, steel plates, etc.

[0075] In one embodiment, liquid film discharge coating does not include curtain flow coating. Droplet discharge coating is a coating method described in Japanese Patent Application Publication No. 2022-044361, in which a paint composition in the form of droplets or liquid columns is applied while controlling the directionality of the droplets and liquid columns by controlling the on and off of discharge. In contrast, spray coating and electrostatic coating are coating methods in which the paint composition is split not by on and off of discharge, but by shearing with air or centrifugal force, and droplets are applied without control over the directionality of each droplet. Therefore, spray coating and electrostatic coating are not included in droplet discharge coating. In one embodiment, the paint composition of the present invention is a paint composition for spray coating or electrostatic coating. In one embodiment, the paint composition of the present invention is a paint composition for liquid film discharge coating or liquid column discharge coating.

[0076] (Coating Film) The coating film according to the present invention is a coating film using any of the above-mentioned coating compositions (for example, a cured film of the coating composition). This results in good water resistance, adhesion, and water resistance / blistering resistance of the coating film.

[0077] The method for forming the coating film is not particularly limited other than using the coating composition of the present invention, and known coating methods can be used. For example, dipping, brushes, rollers, roll coaters, air sprays, airless sprays, electrostatic coating machines, curtain flow coaters, roller curtain coaters, die coaters, Durr's EcoPaintJet®, jet dispensers, etc. can be used.

[0078] Jet dispensers include piezo jet dispensers that control dispensing using a piezoelectric element, and electromagnetic jet dispensers that control dispensing using a solenoid valve. Examples of piezo jet dispensers include the Stream Jet E series manufactured by SSI JAPAN. Examples of electromagnetic jet dispensers include the NOVADOT and JETTY manufactured by San-ei Tech.

[0079] The drying temperature after applying the paint composition can be adjusted as appropriate depending on the solvent and other factors. For example, if drying is required in a short time, such as 10 seconds to 30 minutes, the temperature can be 30 to 200°C, with 40 to 160°C being preferred. If drying is required in a short time, energy rays such as ultraviolet light may be used. If drying is not required in a short time, drying may be done at room temperature, for example. Furthermore, for example, in the case of an automobile body, preheating may be performed at around 80°C to increase the solid content concentration of the paint film, and then it may be baked at 70 to 160°C. In addition, for example, in the case of automobile repair (AR, lacquer), preheating may be performed at 50 to 60°C using a dryer, and the paint film may be cured by letting it stand at room temperature.

[0080] The film thickness of the coating can be adjusted as appropriate depending on the application, for example, the dry film thickness is 3 to 23 μm.

[0081] (Article) The article of this embodiment is an article having the coating film of the present invention.

[0082] Articles having a coating are not particularly limited and include, for example, the interior and exterior of the bodies of vehicles such as automobiles and railway cars, aircraft fuselages, ship hulls and superstructures (outfitting), and the interior, exterior and roof parts of buildings; furniture and fixtures; window glass of vehicles, aircraft, ships, and buildings; cases, containers, resin sheets, and films; housings and glass components of electrical appliances such as displays, monitors, and refrigerators; coatings applied to these; inorganic building materials such as various cements, ceramic building materials, lightweight foamed concrete, mortar, slate boards, roofs, tiles, and ALC; wood; various types of glass; and metal substrates such as steel plates, aluminum, and stainless steel.

[0083] The present invention will be described in more detail below with reference to examples, but these examples are for illustrative purposes only and do not limit the present invention in any way. In the examples, "parts" and "%" are based on mass unless otherwise specified.

[0084] The materials used in the examples are as follows: Surfactant: "Newcol (registered trademark) 293" manufactured by Nippon Emulsifier Co., Ltd. Polyether polyol: "Sannix GP-3000" manufactured by Sanyo Chemical Industries, Ltd. Dispersant: Anionic / nonionic dispersant, "Disperbyk 190" manufactured by Bic Chemie Inc. Antifoaming agent: "BYK-011" manufactured by Bic Chemie Inc. Polyurethane resin: Polyether-based urethane emulsion, "Permarin UA-150" manufactured by Sanyo Chemical Industries, Ltd., resin solids content (NV) 30% by mass, indicated as "Permarin" in the table Curing agent: Imino-type melamine resin, "Cymel 211" manufactured by Ornex Japan Inc., indicated as "Cymel" in the table Polycarbonate resin: Polycarbonate diol, "Duranole" manufactured by Asahi Kasei Corporation T5650E, labeled as "Duranoll" in the table. Water-based epoxy resin: ADEKA Corporation product name "ADEKA Resin (registered trademark) EM-101-50" Cationic electrodeposition paint: Nippon Paint Corporation product name "Power Top U-50" Gray undercoat paint: Polyester / melamine-based paint, Nippon Paint Corporation product name "Orga P-30" Clear paint: Epoxy-curing acrylic resin-based paint, Nippon Paint Corporation product name "Macflow O-1820 Clear" Cellophane tape: Nichiban Silicone-based paint: Nippon Paint Corporation product name "Water-based Fine Si White"

[0085] The viscosities used in the examples are as follows: Carboxyvinyl polymer 1: "Hibis Wako 103" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., referred to as "hv103" in the table Carboxyvinyl polymer 2: "Hibis Wako 104" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., referred to as "hv104" in the table Carboxyvinyl polymer 3: "Hibis Wako 105" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., referred to as "hv105" in the table Diutan gum: "KELCO-VIS" manufactured by CPKelco, Inc., referred to as "Diutan" in the table

[0086] The viscosities used in the examples other than the first viscosity agent are as follows: Alkaline swelling viscosity agent 1: Product name "Primal ASE-60" manufactured by Dow-Toray, indicated as "ASE60" in the table. Alkaline swelling viscosity agent 2: Product name "Viscalex HV30" manufactured by BASF, indicated as "HV30" in the table. Alkaline swelling viscosity agent 3: Product name "SN Thickener 613" manufactured by Sunnopco, modified polyacrylic acid type, indicated as "613" in the table. Alkaline swelling viscosity agent 4: Product name "SN Thickener 618" manufactured by Sunnopco, modified sodium polyacrylate, indicated as "618" in the table. Alkaline swelling viscosity agent 5: Product name "SN Thickener 630" manufactured by Sunnopco, modified polyacrylic acid type, indicated as "630" in the table. Alkaline swelling viscosity agent 6: Product name "SN Thickener" manufactured by Sunnopco Alkaline swelling type viscosity agent 7: Product name "SN Thickener 636" manufactured by Sunnopco, modified polyacrylic acid type, indicated as "634" in the table Alkaline swelling type viscosity agent 8: Product name "SN Thickener 641" manufactured by Sunnopco, modified polyacrylic acid type, indicated as "641" in the table Alkaline swelling type viscosity agent 9: Product name "SN Thickener 640" manufactured by Sunnopco, modified polyacrylic acid type, indicated as "640" in the table Associative viscosity agent 1: Product name "SN Thickener 665T" manufactured by Sunnopco, urethane modified polyether type, indicated as "665T" in the table Associative viscosity agent 2: Product name "SN Thickener 660T: Urethane-modified polyether type, indicated as "660T" in the table. Associative viscosity agent 3: Product name "ADEKA UH-814" manufactured by ADEKA Corporation, urethane-associative type, indicated as "UH814" in the table. Cellulose viscosity agent: Product name "Natrosol HE 3KB" manufactured by Ashland Corporation, hydrophobic modified hydroxyethylcellulose, indicated as "HE3KB" in the table. Aamide viscosity agent: Product name "Disparon AQH-800" manufactured by Kusumoto Chemical Co., Ltd., polyamide amine salt / fatty acid amide, indicated as "AQH800" in the table.

[0087] The equipment used in the example is as follows: Stress-controlled rheometer: MCR302, manufactured by Anton Paar; Rotary atomizing electrostatic coating machine: Cartridge Bell, manufactured by ABB.

[0088] The components to be incorporated into the paint composition were manufactured as shown in the following manufacturing examples 1 to 4.

[0089] Production Example 1: Production of Hydroxyl Group-Containing Acrylic Resin Emulsion 445 parts by mass of water and 5 parts by mass of Newcol 293 were added to a conventional reactor for the production of acrylic resin emulsions, equipped with a stirrer, thermometer, dropping funnel, reflux condenser, and nitrogen inlet tube. The temperature of the reactor was raised to 75°C while stirring the mixture. Next, 5 parts by mass of styrene, 78.11 parts by mass of 2-ethylhexyl acrylate, 16.25 parts by mass of hydroxyethyl methacrylate, 0.64 parts by mass of acrylic acid, 240 parts by mass of water, and 30 parts by mass of Newcol 293 were mixed and emulsified using a homogenizer to obtain an emulsion. Next, 1 part by mass of ammonium persulfate (polymerization initiator) was dissolved in 50 parts by mass of water to obtain an aqueous solution. This emulsion was added dropwise to the reactor while stirring for 3 hours. In parallel with the addition of the emulsion, an aqueous solution of the polymerization initiator was added evenly to the reactor dropwise until the addition of the emulsion was completed. After the emulsion was added dropwise, the reaction was continued at 80°C for another hour. Next, the product in the reactor was cooled. Then, an aqueous solution was prepared by dissolving 2 parts by mass of dimethylaminoethanol in 20 parts by mass of water. This aqueous solution was added to the reactor to adjust the pH of the mixture. Finally, a hydroxyl group-containing acrylic resin emulsion with an NV of 40.6% by mass was obtained.

[0090] Production Example 2: Production of Hydroxyl Group-Containing Polyester Resin In a reactor equipped with a stirrer, thermometer, dropping funnel, reflux condenser, and nitrogen inlet tube, 25.6 parts by mass of isophthalic acid, 22.8 parts by mass of phthalic anhydride, 5.6 parts by mass of adipic acid, 19.3 parts by mass of trimethylolpropane, 26.7 parts by mass of neopentyl glycol, 17.5 parts by mass of ε-caprolactone, and 0.1 parts by mass of dibutyltin oxide were added. The mixture was then heated to 170°C while stirring. The temperature of the reactor was then raised to 220°C over 3 hours while removing the water produced by the condensation reaction. The water produced was removed until the acid value of the mixture in the reactor was 8 mg KOH / g. Next, 7.9 parts by mass of trimellitic anhydride was added to the mixture in the reactor. The reaction was then continued at 150°C for 1 hour to obtain a polyester resin with an acid value of 40 mg KOH / g. The temperature of the reactor was then cooled to 100°C. Next, 11.2 parts by mass of butyl cellosolve was added to the mixture in the reactor and stirred until homogeneous. Then, the reactor temperature was cooled to 60°C. Next, 98.8 parts by mass of deionized water and 5.9 parts by mass of dimethylethanolamine were added to the mixture in the reactor. A hydroxyl group-containing polyester resin with the following characteristics was obtained: NV: 50% by mass; Solid content acid value: 40 mg KOH / g; Solid content hydroxyl value: 110 mg KOH / g; Number average molecular weight (Mn): 2870; Glass transition temperature (Tg): -3°C

[0091] Production Example 3: Production of Carbodiimide Compounds 3,930 parts by mass of 4,4-dicyclohexylmethane diisocyanate were reacted with 79 parts by mass of 3-methyl-1-phenyl-2-phosphorene-1-oxide (carbodiimide catalyst) at 180°C for 16 hours to obtain a carbodiimide compound. This compound has four carbodiimide groups per molecule and isocyanate groups at both ends. To the mixture containing this carbodiimide compound, 1,296 parts by mass of polyethylene glycol monomethyl ether and 2 parts by mass of dibutyltin dilaurate were added. The polyethylene glycol monomethyl ether has an average of 9 repeating units of oxyethylene groups. Next, the mixture was heated at 90°C for 2 hours to obtain a carbodiimide compound. This compound has isocyanate groups and hydrophilic groups at its ends. Next, 3,000 parts by mass of polyether polyol were added to the mixture. The mixture was reacted at 90°C for 6 hours. The disappearance of the isocyanate group from the reaction product was confirmed by IR. 18,800 parts by mass of deionized water were added to the reaction product and stirred. A aqueous dispersion of the carbodiimide compound with a resin solid content of 30% by mass was then obtained.

[0092] Manufacturing Example 4: Production of Pigment Dispersion Paste 4.5 parts by mass of dispersant, 0.5 parts by mass of defoaming agent, 22.9 parts by mass of deionized water, and 72.1 parts by mass of rutile-type titanium dioxide were premixed. Then, a glass bead medium was added to the mixture in paint conditioner. The mixture was then mixed and dispersed at room temperature until the particle size was 5 μm or less to obtain a pigment dispersion paste.

[0093] • Preparation of Base Composition A: Base composition A was prepared by mixing each component with deionized water according to the formulation shown in Table 1. The amount of deionized water was such that the non-volatile content (NV) of base composition A was 24.1% by mass.

[0094] Preparation of base composition B A silicone resin emulsion was prepared according to Production Example 1 of Japanese Patent Publication No. 2019-137707. Then, instead of 30 parts by mass of hydroxyl group-containing acrylic resin emulsion in Production Example 1 of base composition A, 28.6 parts by mass of the silicone resin emulsion and deionized water were blended to form base composition B. The amount of deionized water was such that the NV of base composition B was 24.1% by mass.

[0095] - Preparation of base composition C A fluororesin emulsion (A-1) was prepared according to Example 1 of Japanese Patent Publication No. 2021-038319. Then, instead of 30 parts by mass of the hydroxyl group-containing acrylic resin emulsion in Production Example 1 of base composition A, 23.8 parts by mass of the fluororesin emulsion and deionized water were blended to form base composition C. The amount of deionized water was such that the NV of base composition C was 24.1% by mass.

[0096] Preparation of base composition D: Epoxyamine resin V was prepared according to Production Example 5 of Japanese Patent Publication No. 2016-216689. Then, 30.8 parts by mass of the epoxyamine resin V and deionized water were blended in place of 30 parts by mass of the hydroxyl group-containing acrylic resin emulsion in Production Example 1 of base composition A to form base composition D. The amount of deionized water was such that the NV of base composition D was 24.1% by mass.

[0097] - Preparation of base composition E: In the production example of base composition A, 30 parts by mass of hydroxyl group-containing acrylic resin emulsion was replaced with 26.2 parts by mass of aqueous epoxy resin and deionized water to form base composition E. The amount of deionized water was such that the NV of base composition E was 24.1% by mass.

[0098] Example 1: Preparation of an aqueous coating composition 644.6 parts by mass of base composition A were mixed with carboxyvinyl polymer 1 and deionized water in the proportions shown in Table 2 and stirred to obtain the aqueous coating composition of Example 1. The amount of deionized water was set to the amount at which the NV of the aqueous coating composition became the calculated NV shown in Table 2.

[0099]

[0100] In Tables 2 to 7, "Viscosity Solids (%)" represents the ratio of the viscosity content (mass) to the total mass of the aqueous paint composition.

[0101] Examples 2-11: Aqueous paint compositions were prepared in the same manner as in Example 1, except that the type or amount of the viscous agent was changed as shown in Table 2.

[0102] Examples 12-15: Aqueous paint compositions were prepared in the same manner as in Example 1, except that the type or amount of the base composition and viscous agent was changed as shown in Table 3.

[0103] Comparative Examples 1-18: Water-based paint compositions were prepared in the same manner as in Example 1, except that the type or amount of the viscous agent was changed as shown in Tables 4-6. In Tables 4-6, "NE1" indicates that the evaluation was not performed because the evaluation of sagging resistance was unsatisfactory; "NE2" indicates that the evaluation was not performed because the paint had poor workability and could not be practically used as a paint; and "NE3" indicates that the evaluation was not performed because the paint separated.

[0104]

[0105]

[0106]

[0107]

[0108] Preparation of the intermediate coating: A zinc phosphate-treated, 0.8 mm thick, 70 mm x 150 mm size SPCC-SD steel plate (dull steel plate) was electrodeposited with cationic electrodeposition paint to a dry film thickness of 20 μm. The coating was then baked at 160°C for 30 minutes. Next, gray intermediate coating paint was diluted to a viscosity of 25 seconds (measured at 20°C using a No. 4 Ford cup). The diluted gray intermediate coating paint was then electrostatically applied to the electrodeposited plate to a dry film thickness of 35 μm. The coating was then baked at 140°C for 30 minutes to form the intermediate coating. The steel plate with this electrodeposited coating and intermediate coating was designated as workpiece A for evaluation described later.

[0109] For each example and comparative example of the aqueous paint composition, the following measurements (1) and (2) were performed, and evaluations (3) to (5) were conducted. The results are shown in Tables 2 to 6.

[0110] (1) Viscosity (η1 and η2) For the aqueous paint compositions of each example and comparative example, a stress-controlled rheometer was used to measure the shear rate (dγ / dt) = 10s under the conditions of a 50 mm parallel plate, a gap of 0.5 mm, and a measurement temperature of 23°C. －１ and 1000s －１ Steady flow measurements were performed under shear deformation. The steady-state viscosity values ​​(Pa·s) 30 seconds after the start of measurement were defined as η1 and η2, respectively.

[0111] (2) Slope of creep compliance For each example and comparative example of the aqueous paint composition, creep measurements were performed using a stress-controlled rheometer at a temperature of 23°C and a stress of 1 Pa, and the value of dJ(t) / dt (i.e., the slope of creep compliance) was read when dJ(t) / dt became constant. Here, J(t) is the value of creep compliance (Pa －１ ) represents the time (s), where t represents time. Also, "when dJ(t) / dt becomes constant" means that the variation in the measured values ​​over 10 seconds is within ±2% of the average value. Measurements were taken at 1-second intervals, and the average value was calculated by dividing the sum of the 10 measured values ​​taken over 10 seconds by 10. In the table, "E-x" ​​is 10 －ｘ The exponent is represented by "E + x", and "E + x" is 10 ＋ｘ It represents the exponent. For example, "6.3E-02" is 6.3 × 10⁻¹⁰. －２ This represents "6.6E+00", and "6.6E+00" is 6.6 × 10 ０ That is, it represents 6.6.

[0112] (3) VOC content The VOC content (g / L) of the aqueous paint compositions of each example and comparative example was calculated using the following formula (1). In formula (1), the meaning of each symbol is as follows: ρ (VOC): VOC content (g / L) ω (NV): Non-volatile content, expressed as mass fraction (%) ω (w): Water content, expressed as mass fraction (%) ρ (a): Specific gravity of paint at 23°C (g / mL) ρ (w): Specific gravity of water at 23°C (= 0.997537 g / mL) In formula (1), "1000" is the conversion factor from g / mL to g / L.

[0113] (4) The sagging-resistant water-based paint composition was applied to the intermediate coat film of the substrate A using a sagging tester. The painted substrate A was immediately propped up vertically. At 23°C, the limit of wet film thickness at which sagging did not occur was measured, and the sagging resistance was evaluated according to the following criteria. Pass indicates good sagging resistance. The results are shown in Tables 2 to 6. Pass: Wet film thickness of 175 μm or more Fail: Wet film thickness less than 175 μm

[0114] (5) Separation of paint A 20 mL sample of the aqueous paint composition was placed in a sample tube and left to stand at 20°C for one month. After one month, the presence or absence of separation of the paint composition was visually observed to confirm whether separation had occurred. If there was no separation in the paint composition, it indicated that the paint properties were good. The results are shown in Tables 2 to 6.

[0115] Preparation of the coating film: The aqueous coating compositions of each example and comparative example were applied to the intermediate coating film of substrate A using a rotary atomizing electrostatic coating machine to a dry film thickness of 15 μm. Next, the wet coating film was preheated at 80°C for 5 minutes, and then the clear coating was applied wet-on-wet using a rotary atomizing electrostatic coating machine to a dry film thickness of 35 μm. After coating, the film was baked at 140°C for 30 minutes to obtain a multi-layer coating film.

[0116] The obtained multilayer coating was used as a test specimen, and the following evaluations (6) to (7) were performed. The results are shown in Tables 2 to 6.

[0117] (6) Water resistance and blister resistance The water resistance and blister resistance of the coating film on the test specimens were evaluated by the following test. The test specimens were immersed in 80°C water for 1 hour. Then, the test specimens were transferred to room temperature water and left to stand for 10 minutes to cool. Next, the test specimens were removed from the water, and the appearance of the coating film was visually observed and evaluated according to the following criteria. The results are shown in Tables 2 to 6. Pass: No blistering in the coating film Fail: Blisters in the coating film

[0118] (7) Water-resistant adhesion The water-resistant adhesion of the coating on the test specimen was evaluated by the following test. The test specimen was immersed in 80°C water for 1 hour. Next, the test specimen was transferred to room temperature water and left to cool for 10 minutes. Next, the test specimen was removed from the water. Next, 10 vertical and 10 horizontal cuts were made in the coating of the test specimen with a cutter at 1 mm intervals, and cellophane tape was applied over the cuts and peeled off. The number of squares that remained without peeling out of 100 squares was counted. The following criteria were used for evaluation. The results are shown in Tables 2 to 6. Pass: 100 squares remained and there was no peeling of the coating. Fail: 0 to 99 squares remained and there was peeling of the coating.

[0119] Example 16: Preparation of a silicone-based aqueous paint composition A commercially available silicone-based paint, "Water-based Fine Si White," was used as the base composition F. Then, 92.5 parts by mass of base composition F was used instead of 644.59 parts by mass of base composition A, and carboxyvinyl polymer 1 was added in the proportions shown in Table 7 and stirred to obtain the silicone-based aqueous paint composition of Example 16.

[0120] Examples 17-23 and Comparative Examples 19-21: Silicone-based aqueous coating compositions were prepared in the same manner as in Example 16, except that the type or amount of the viscous agent was changed as shown in Table 7.

[0121]

[0122] For the aqueous coating compositions of Examples 16-23 and Comparative Examples 19-21, measurements (1) and (2) were performed in the same manner as in Example 1, and evaluations (3) to (5) were performed. The results are shown in Table 7.

[0123] In Example 1, a multilayer coating was obtained in the same manner as in Example 1, except that the aqueous coating composition of Example 1 was replaced with the aqueous coating compositions of Examples 16-23 and Comparative Examples 19-21. The obtained multilayer coating was used as a test piece, and evaluations (6) to (7) were performed in the same manner as in Example 1. The results are shown in Table 7.

[0124] According to the present invention, even with zero or small amounts of hydrophobic solvent content, phase separation does not occur during storage of the paint, and a paint with good water-resistant adhesion, water-resistant blistering, and sagging resistance of the paint film can be provided.

[0125] According to the present invention, even if the hydrophobic solvent content is zero or small, phase separation does not occur during storage of the paint, and a paint with good water resistance, adhesion, water resistance, blister resistance, and sagging resistance of the paint film can be provided.

Claims

1. A paint composition comprising a film-forming resin and a viscous agent, wherein the viscous agent comprises at least one selected from the group consisting of carboxyvinyl polymer and dieutan gum, and the paint composition is subjected to 23°C and a shear rate of 10 s. －１ The steady-state viscosity η1 measured during steady-state flow measurement of shear deformation is 0.10 to 0.90 Pa·s, and the temperature is 23°C and the shear rate is 1,000 s. －１ The steady-state viscosity η² in steady-state flow measurement of shear deformation is 0.02 to 0.09 Pa·s, and creep measurement is performed on the paint composition under conditions of 23°C and stress of 1 Pa, where t is time (s) and J(t) is the creep compliance value (Pa). －１ When dJ(t) / dt becomes constant, the value of dJ(t) / dt is 1.8 × 10⁻¹⁰. －１ The following is the paint composition.

2. The paint composition according to claim 1, wherein the content of the viscous agent is 0.01 to 0.7% by mass with respect to the total mass of the paint composition.

3. The paint composition according to claim 1, wherein the non-volatile content (NV) of the paint composition is 1 to 80% by mass with respect to the total mass of the paint composition.

4. The paint composition according to claim 1, wherein it is an aqueous paint composition.

5. The paint composition according to claim 1, further comprising an alkali swelling type viscosity agent.

6. A coating film using the coating composition described in claim 1.

7. An article having the coating film described in claim 6.

Images