JP7445161B1 - Paint compositions and coatings - Google Patents

Abstract

[Object] To provide a coating composition that can form a coating film with excellent brightness, flip-flop properties, and surface smoothness.
[Solution] The resin particles (A) include resin particles (A), transparent beads (B), and a dispersion medium (C) for dispersing the resin particles (A) and the transparent beads (B). , a droplet containing an aqueous paint, and a gelled film covering the surface of the droplet, the aqueous paint comprising an aqueous medium, an aqueous resin (D), and a pigment (E) dispersed in the aqueous medium. The content of the pigment (E) is 14% by mass or more based on 100% by mass of the aqueous resin (D), and the dispersion medium (C) contains an aqueous medium and an aqueous resin (F). The content of the transparent beads (B) is 20 to 135% by mass based on 100% by mass of the aqueous resin (F), and the average particle diameter of the transparent beads (B) is 10 μm or more. Paint composition.
[Selection diagram] Figure 1

Description

The present invention relates to a coating composition and a coating film.

The surfaces of many building materials are painted for protection and decoration purposes.
In recent years, there has been a demand for designs with a more luxurious feel, and metallic paints that can provide designs with sparkling brightness are particularly preferred.

Patent Document 1 discloses a method comprising resin particles and a dispersion medium for dispersing the resin particles, wherein the resin particles have droplets containing an emulsion paint and a gelled film covering the surface of the droplets. , a coating composition in which the emulsion coating comprises a resin emulsion and a pigment dispersed in the resin emulsion, the dispersion medium contains water as a main component, and the specific gravity of the pigment is 2.5 or more. is disclosed.

JP2021-038275A

According to the coating composition described in Patent Document 1, even if it contains pigments with high specific gravity such as nickel, stainless steel, and MIO, the pigments are difficult to settle, and a good appearance can be achieved during coating, thereby improving the sense of brightness. Can form a certain coating film. However, a coating film appearance with higher brightness is sometimes required.

The present inventor attempted to obtain a coating film appearance with higher brightness by increasing the amount of metallic pigment contained in the resin particles of the coating composition of Patent Document 1. As a result, although a coating film appearance with higher brightness was obtained, on the other hand, it was found that flip-flop properties deteriorated.
Here, the flip-flop property in the present invention refers to the property that the brightness of the coating film changes depending on the viewing angle. The smaller the change in brightness, the better the flip-flop property, which means that the amount of reflected light that can be sensed (brightness) does not change even if the viewing angle of the film is changed. .

The present inventor has found that by increasing the content of metallic pigment in resin particles, the metallic pigment in the coating film before film formation becomes more likely to be oriented parallel to the base material as it dries, resulting in flip-flop properties. I thought it had gotten worse.
Therefore, when we increased the viscosity of the resin emulsion contained in the resin particles and the viscosity of the coating composition so that the metallic pigment was oriented randomly with respect to the base material, the flip-flop properties improved, but the leveling properties worsened. Ta. As a result, the surface of the paint film was no longer smooth, and it no longer had a ``smooth, sparkling, metal-like design.'' Even when the paint composition is applied to a substrate with uneven surfaces, the flip-flop properties are improved, but the result is a coating film with uneven surfaces and no longer has a ``smooth, sparkling, metal-like design.'' Ta.

The present invention aims to provide a coating composition capable of forming a coating film with excellent brightness, flip-flop properties, and surface smoothness, and a coating film with excellent brightness, flip-flop properties, and surface smoothness.

The present invention has the following aspects.
[1] A coating composition comprising resin particles (A), transparent beads (B), and a dispersion medium (C) in which the resin particles (A) and the transparent beads (B) are dispersed,
The resin particles (A) include droplets containing a water-based paint and a gelled film covering the surface of the droplets,
The aqueous paint includes an aqueous medium, an aqueous resin (D), and a pigment (E) dispersed in the aqueous medium,
The content of the pigment (E) is 14% by mass or more based on 100% by mass of the aqueous resin (D),
The dispersion medium (C) includes an aqueous medium and an aqueous resin (F),
The content of the transparent beads (B) is 20 to 135% by mass with respect to 100% by mass of the aqueous resin (F),
A coating composition characterized in that the transparent beads (B) have an average particle diameter of 10 μm or more.
[2] The coating composition according to [1] above, wherein the pigment (E) is a flat particle.
[3] A coating film formed from the coating composition according to [1] or [2] above.
[4] The coating film according to [3], wherein the value obtained by dividing the average particle diameter (μm) of the transparent beads (B) by the average film thickness (μm) of the coating film is 0.1 or more.

According to the present invention, it is possible to provide a coating composition that can form a coating film with excellent brightness, flip-flop properties, and surface smoothness, and a coating film with excellent brightness, flip-flop properties, and surface smoothness.

FIG. 1 is a schematic diagram illustrating a coating composition according to one embodiment. FIG. 2 is a schematic diagram illustrating resin particles (A) shown in FIG. 1. FIG.

A coating composition according to an embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Note that in all the drawings below, the dimensions and ratios of each component are changed as appropriate to make the drawings easier to read.

[Coating composition]
FIG. 1 is a schematic diagram illustrating a coating composition 1 according to an embodiment of the present invention.
As shown in FIG. 1, the coating composition 1 includes resin particles (A) 10, transparent beads (B) 20, and a dispersion medium (C) in which the resin particles (A) 10 and the transparent beads (B) 20 are dispersed. 30.

<Resin particles (A)>
FIG. 2 is a schematic diagram illustrating the resin particles (A) 10.
As shown in FIG. 2, the resin particles (A) 10 include a droplet 11 and a gelled film 12 that covers the surface of the droplet 11.
The number of resin particles (A) in the coating composition 1 may be one, or two or more. For example, it may contain two or more types of resin particles (A) having mutually different color tones.

The average particle diameter of the resin particles (A) is preferably 0.1 mm to 5 cm, more preferably 0.1 mm to 3 cm, and particularly preferably 0.1 mm to 2 cm. If the average particle diameter of the resin particles (A) is within the above range, the resulting coating film will have excellent design. Moreover, the workability of painting using an air gun is also good.
The average particle diameter of the resin particles (A) is a value obtained by measuring the long diameters of 20 randomly selected resin particles (A) using a caliper and calculating the arithmetic average of each measured value.

(droplet)
Droplet 11 contains water-based paint.
The aqueous paint includes an aqueous medium, an aqueous resin (D), and a pigment (E) dispersed in the aqueous medium.

"Aqueous medium"
The aqueous medium is a medium containing only water or a medium containing water and a solvent compatible with water. The proportion of water to the total mass of the aqueous medium is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more.
As water, ion exchange water, tap water, etc. can be used.
Examples of solvents that are compatible with water include alcohols such as ethanol and isopropyl alcohol, and ethylene glycol. These solvents may be used alone or in combination of two or more.

"Aqueous resin (D)"
The aqueous resin (D) is a resin that can be dissolved or dispersed in an aqueous medium. The aqueous resin (D) is preferably a resin that can be dispersed in an aqueous medium (water-dispersible resin).
The type of aqueous resin (D) is not particularly limited and can be selected as appropriate depending on the performance required of the coating composition. The water-based resin (D) is preferably one that provides good water resistance and weather resistance to the coating film.
Examples of the types of aqueous resin (D) include acrylic resin, urethane resin, vinyl acetate resin, silicone resin, fluororesin, acrylic urethane resin, acrylic silicone resin, acrylic fluororesin, acrylic polyol resin, acrylic styrene resin, and acrylonitrile resin. , vinyl chloride resin, epoxy resin, Beoba (branched fatty acid vinyl ester), natural rubber, synthetic rubber, and copolymers thereof. These aqueous resins may be used alone or in combination of two or more. Among these, synthetic resins such as acrylic resins, acrylic silicone resins, and acrylic fluororesins are preferred because they have excellent water resistance and weather resistance.

"Pigment (E)"
Pigment (E) is dispersed within the droplets.
As the pigment (E), a pigment having glittering properties such as metallic luster is preferable. Pigments with glitter include, for example, flaky metal pigments such as nickel, stainless steel, and aluminum; calcined mica; glass, mica, etc., metal oxides such as iron oxide, titanium oxide, and zirconia; silver, gold, etc. Examples include flake pigments coated with metals. These may be used alone or in combination of two or more.

The average particle diameter of the pigment (E) is preferably 0.1 μm or more, more preferably 1 μm or more, from the viewpoint of forming a high-brightness coating film. The upper limit of the average particle diameter of the pigment (E) may be within the resin particles (A) and may be smaller than the resin particles (A). For example, it is preferably 10 mm or less, more preferably 5 mm or less.
The average particle diameter of the pigment (E) is a volume-based median diameter (D50), and specifically, it is a value measured using a laser diffraction particle size distribution measuring device.

Pigment (E) can adopt various particle shapes such as spherical particles and flat particles, but flat particles are preferable. When the pigment (E) is a flat particle, when the coating composition is applied, the pigment (E) tends to reflect light and tends to impart metallic luster to the object to which the coating composition is applied.
In addition, in this specification, "flat grains" mean grains with an average aspect ratio of 5 or more.
The aspect ratio is determined from the ratio of the major axis of the flat particle to the minor axis of the flat particle. The major axis and minor axis of the flat particles are determined from electron micrographs. Assuming the smallest rectangle circumscribing a flat particle in an electron micrograph, the long side of the rectangle is the major axis of the flat particle, and the short side of the rectangle is the short axis.
The average aspect ratio refers to the value obtained by calculating the aspect ratios of each of the 20 flat grains in one field of view of the above-mentioned electron micrograph, and calculating the arithmetic average of the calculated aspect ratios.

"Colloid-forming substances"
Water-based paints typically include colloid-forming substances.
The colloid-forming substance is a substance that can form the gelled film 12 by reacting with the gelling agent. The gelling agent will be described later.

Examples of colloid-forming substances include cellulose derivatives such as hydroxycellulose, hydroxypropylmethylcellulose, hydroxypropylcellulose, carboxylmethylcellulose, and ethylcellulose, guar gum, guar gum derivatives, galactomannans such as fenugreek gum, tara gum, locust bean gum, and cassia gum, welan gum, Biogum such as gellan gum and xanthan gum; polysaccharides such as alginic acid, alginic acid derivatives, and starch; alcohols such as polyvinyl alcohol, glycerin, and ethylene glycol; aqueous urethane; polyethyleneimine derivatives; polyvinyl vinylidone; polyacrylic acid derivatives; casein, etc. It will be done. These colloid-forming substances may be used alone or in combination of two or more. As the colloid-forming substance, guar gum and guar gum derivatives are preferred.
Colloid-forming substances are typically used in the form of aqueous solutions. The concentration of the colloid-forming substance aqueous solution is, for example, 0.1% by mass or more and 10% by mass or less.

(gel membrane)
The gelled film 12 covers the surface of the droplet 11 and forms the outline of the resin particle (A).
The gelled film 12 typically includes a three-dimensional network formed by the reaction and crosslinking of a colloid-forming substance contained in the water-based paint with a gelling agent. The gelled film 12 has lower fluidity than the water-based paint and contains droplets 11 therein.

Examples of the gelling agent include magnesium montmorillonite clay, sodium pentachlorophenol, borates, aluminum salts, barium salts, calcium salts, magnesium salts, tannic acid, titanium lactate, calcium chloride, and the like. Among these, an aqueous solution of borate is preferred. One type of gelling agent may be used alone or two or more types may be used in combination.

(optional ingredient)
The resin particles (A) may contain an extender pigment as long as there is no problem with the appearance or performance of the coating film.
Extender pigment is a general term for achromatic pigments used in paints. Examples of extender pigments include kaolin, barium sulfate, hydrous magnesium silicate, and calcium carbonate. Extender pigments may be used alone or in combination of two or more.

The resin particles (A) may contain known additives, if necessary. Known additives include, for example, emulsifiers, pH adjusters, antifoaming agents, viscosity modifiers, film forming aids, freeze inhibitors, dispersants, wetting agents, penetration aids, preservatives, surface conditioners, and ultraviolet rays. Examples include absorbents, antioxidants, heat shields, and the like.

The content of solids in the resin particles (A) is preferably 75% by mass or less, more preferably 70% by mass or less, particularly preferably 65% by mass or less, based on 100% by mass of the resin particles (A).
The solid content in the resin particles (A) is the remainder after removing the aqueous medium from the resin particles (A).

The content of the aqueous resin (D) in the resin particles (A) is preferably 1% by mass or more, more preferably 5% by mass or more, particularly preferably 10% by mass or more, based on 100% by mass of the resin particles (A). . When the content of the aqueous resin (D) is equal to or higher than the lower limit, the stability of the droplets tends to be excellent.
The content of the aqueous resin (D) in the resin particles (A) is preferably 70% by mass or less, more preferably 65% by mass or less, particularly preferably 60% by mass or less, based on 100% by mass of the resin particles (A). . If the content of the aqueous resin (D) is below the upper limit, fluidity tends to be excellent.
The above upper and lower limits can be arbitrarily combined.

The content of the pigment (E) in the resin particles (A) is 14% by mass or more, preferably 19% by mass or more, more preferably 23% by mass or more, 28% by mass or more, based on 100% by mass of the aqueous resin (D). It is more preferably at least 33% by mass, particularly preferably at least 33% by mass. When the content of the pigment (E) is at least the lower limit, a coating film with high brightness can be obtained.
The content of the pigment (E) is preferably 300% by mass or less, more preferably 200% by mass or less, based on 100% by mass of the aqueous resin (D). If the content of the pigment (E) is below the above upper limit, the capsule structure of the resin particles (A) will not be easily broken during manufacturing or coating, and the coating film performance will be excellent. Considering the viewpoint of reducing costs, the content is more preferably 100% by mass or less, even more preferably 80% by mass or less, and particularly preferably 60% by mass or less.
The above upper and lower limits can be arbitrarily combined.

The ratio of the volume of the pigment (E) to 100 volume % of the resin solid content in the resin particles (A) is preferably 5 volume % or more and 80 volume % or less. If the volume ratio of the pigment (E) is equal to or greater than the lower limit, a coating film with high brightness can be obtained. If the volume ratio of the pigment (E) is below the above-mentioned upper limit, the capsule structure of the resin particles (A) will not be easily broken during manufacturing or coating, and the coating film performance will be excellent.

The content of the colloid-forming substance in the resin particles (A) is preferably 0.05 to 5 parts by weight, more preferably 0.1 to 3.0 parts by weight, based on 100 parts by weight of the aqueous resin (D). By controlling the content of the colloid-forming substance within the above range, a stable gelled film can be obtained.

<Transparent beads (B)>
The transparent beads (B) need only be able to transmit light, and both organic and inorganic beads can be used. Examples of the organic transparent beads (B) include those based on acrylic resin, urethane resin, silicone resin, and polystyrene resin. Examples of the inorganic transparent beads (B) include glass beads. Furthermore, for example, glass beads whose surfaces are coated with a resin or the like can also be used. These transparent beads (B) may be used alone or in combination of two or more.
As the transparent beads (B), both colored and colorless beads can be used, but colorless beads are preferable.

The refractive index of the transparent beads (B) is preferably 1 or more, more preferably 1.3 or more, and even more preferably 1.45 or more. When the refractive index is 1 or more, the brightness and flip-flop properties of the coating film are better.
The refractive index of the transparent beads (B) is preferably 2 or less, more preferably 1.8 or less, and even more preferably 1.6 or less. When the refractive index is 2 or less, the brightness and flip-flop properties of the coating film are better.
The above upper and lower limits can be arbitrarily combined.

The average particle diameter of the transparent beads (B) is 10 μm or more, preferably 15 μm or more, more preferably 25 μm or more, even more preferably 40 μm or more, and particularly preferably 80 μm or more. If the average particle diameter of the transparent beads (B) is equal to or larger than the lower limit, the flip-flop properties of the coating film will be excellent.
The average particle diameter of the transparent beads (B) is preferably 400 μm or less, more preferably 350 μm or less, even more preferably 300 μm or less, even more preferably 350 μm or less, particularly preferably 300 μm or less. If the average particle diameter of the transparent beads (B) is below the above-mentioned upper limit, the surface smoothness of the coating film will be more excellent.
The average particle diameter of the transparent beads (B) is a volume-based median diameter (D50), and specifically, it is a value measured using a laser diffraction particle size distribution measuring device.

<Dispersion medium (C)>
The dispersion medium (C) includes an aqueous medium and an aqueous resin (F).

"Aqueous medium"
Examples of the aqueous medium in the dispersion medium (C) include those similar to those in aqueous paints. The aqueous medium in the dispersion medium (C) and the aqueous medium in the aqueous paint may be the same or different.

"Water-based resin (F)"
Examples of the water-based resin (F) include those similar to the water-based resin (D).
It is preferable that the aqueous resin (F) and the aqueous resin (D) have the same form and type. An example is an example in which both the aqueous resin (F) and the aqueous resin (D) are acrylic silicone resins that can be dispersed in an aqueous medium.
The aqueous resin (F) and the aqueous resin (D) may be different in type. An example is an example in which the aqueous resin (F) is an acrylic silicone resin and the aqueous resin (D) is an acrylic resin.

"Other ingredients"
The dispersion medium (C) typically contains the above-mentioned gelling agent.
The dispersion medium (C) may contain the above-mentioned colloid-forming substance.
The dispersion medium (C) may contain the above-mentioned pigment (E).
The dispersion medium (C) may contain known additives as necessary. Known additives include those mentioned above.

The content of the aqueous resin (F) in the dispersion medium (C) is preferably 5% by mass or more, more preferably 10% by mass or more, particularly preferably 15% by mass or more, based on 100% by mass of the dispersion medium (C). .
The content of the aqueous resin (F) in the dispersion medium (C) is preferably 90% by mass or less, more preferably 85% by mass or less, particularly preferably 80% by mass or less, based on 100% by mass of the dispersion medium (C). .
If the content of the aqueous resin (F) is at least the above lower limit, the coating film performance, such as water resistance, tends to be excellent, and when it is below the above upper limit, the paint tends to have excellent storage stability.
The above upper and lower limits can be arbitrarily combined.

<Content of each component>
In the coating composition, the content of the transparent beads (B) is 20% by mass or more, preferably 25% by mass or more, more preferably 30% by mass or more, 35% by mass or more, based on 100% by mass of the aqueous resin (F). % or more is particularly preferred.
The content of the transparent beads (B) is 135% by mass or less, preferably 130% by mass or less, more preferably 125% by mass or less, particularly preferably 120% by mass or less, based on 100% by mass of the aqueous resin (F). .
When the content of the transparent beads (B) is within the above range, a smooth coating film with high brightness and good flip-flop properties can be formed.
The above upper and lower limits can be arbitrarily combined. For example, the content of the transparent beads (B) is 20 to 135% by mass, 25 to 130% by mass, 30 to 125% by mass, or 35 to 120% by mass based on 100% by mass of the aqueous resin (F). good.

The content of the resin particles (A) in the coating composition is preferably 10% by mass or more, more preferably 15% by mass or more, based on a total of 100% by mass of the resin particles (A) and the dispersion medium (C). Particularly preferred is 20% by mass or more.
The content of the resin particles (A) is preferably 95% by mass or less, more preferably 90% by mass or less, and 85% by mass or less with respect to the total 100% by mass of the resin particles (A) and the dispersion medium (C). Particularly preferred.
When the content of the resin particles (A) is within the above range, a coating film with high brightness can be formed.
The above upper and lower limits can be arbitrarily combined. For example, the content of the resin particles (A) in the coating composition is 10 to 95 mass%, 15 to 90 mass%, or It may be from 20 to 85% by weight.

The content of the dispersion medium (C) in the coating composition is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total of 100% by mass of the resin particles (A) and the dispersion medium (C). Particularly preferred is 15% by mass or more.
The content of the dispersion medium (C) in the coating composition is preferably 90% by mass or less, more preferably 85% by mass or less, based on the total 100% by mass of the resin particles (A) and the dispersion medium (C). Particularly preferred is 80% by mass or less.
When the proportion of the dispersion medium (C) in the coating composition is within the above range, a coating film with high brightness can be formed.
The above upper and lower limits can be arbitrarily combined.

<Method for producing coating composition>
The above-mentioned coating composition includes, for example, a dispersion in which resin particles (A) are dispersed in an aqueous medium (hereinafter also referred to as a resin particle (A) dispersion), transparent beads (B), an aqueous resin (F), and the like. It can be produced by mixing additional aqueous media, other components, etc., depending on the situation.

The resin particle (A) dispersion can be manufactured, for example, by the following manufacturing method.
First, a mixed solution (d) is prepared by mixing an aqueous resin (D), an aqueous medium, and an aqueous solution of a colloid-forming substance.
Separately, a mixed liquid (e) is prepared by mixing the pigment (E) and, if necessary, an aqueous medium and additives such as a dispersant.
Next, the mixed liquid (d) and the mixed liquid (e) are mixed to prepare a water-based paint (c).
Separately, an aqueous solution (f) is prepared by mixing a gelling agent, an aqueous medium, and, if necessary, a colloid-forming substance and additives.
Next, the aqueous paint (c) is added to the aqueous solution (f) while stirring the aqueous solution (f) with a disperser.
When the water-based paint (c) is stirred in the aqueous solution (f), droplets of the water-based paint (c) are formed, and the colloid-forming substance contained in the droplets and the gelling agent contained in the aqueous solution (f) are A three-dimensional network (gelled membrane) is formed by reacting and crosslinking. Further, the water-based paint (c) is aggregated by reaction with the gelling agent, and is then finely divided by stirring. Even in the process of fragmentation, the colloid-forming substance and the gelling agent continue to react, forming a three-dimensional network (gelled membrane). As a result, resin particles (A) in which droplets of the water-based paint (c) are coated with a gelled film are obtained.
In this way, the agglomerates of the water-based paint (c) are fragmented while the colloid-forming substance and the gelling agent react, resulting in resin particles (A) in which the resin particles (A) are dispersed in the aqueous solution (f). ) A dispersion is obtained.
Two or more types of resin particle (A) dispersions having different color tones of the resin particles (A) may be prepared and mixed.

<Painting method>
A coating film is formed by applying the coating composition according to this embodiment onto a substrate and drying it.

There are no particular restrictions on the base material, and ceramic siding boards, flexible boards, calcium silicate boards, gypsum slag barlite boards, wood chip cement boards, asbestos cement boards, pulp cement boards, precast concrete boards, lightweight aerated concrete (ALC) It can be applied to various objects such as ceramic building material boards such as boards and gypsum boards, metal building material boards such as aluminum, iron, and stainless steel, mortar, plastic, wood, and paper. Further, these surfaces may be subjected to a base treatment using a sealer, a primer, or the like.

There is no particular restriction on the method of applying the coating composition, and the coating composition can be applied by any known application method such as brush, trowel, roller, spray coating, roll coating, flow coating, or the like.
The coating amount of the coating composition can be appropriately selected depending on the average thickness of the coating film to be formed, but the mass per unit area before drying (wet) is preferably 50 to 1000 g/ ^m2 , and 100 to 1000 g/m2. 800 g/m ² is more preferred. If the coating amount is equal to or greater than the lower limit value, there is a tendency for the coating film performance such as water resistance, brightness, and flip-flop properties to be excellent. If the coating amount is below the upper limit, problems such as cracking of the coating film during drying tend to be less likely to occur. The above upper and lower limits can be arbitrarily combined.
Drying may be carried out as long as the aqueous medium can be removed, and may be drying at room temperature or drying with heat. The drying temperature is, for example, 5 to 90°C. The drying time varies depending on the drying temperature, but is, for example, 5 minutes to 48 hours.
After drying, a top coat may be further applied on the formed coating film to provide a top coat.

<Coating film>
The average thickness of the coating film formed from the coating composition according to this embodiment is preferably 100 μm or more, more preferably 120 μm or more, and particularly preferably 140 μm or more. If the average film thickness of the coating film is equal to or greater than the lower limit value, there is a tendency for the coating film performance such as water resistance, brightness, and flip-flop properties to be excellent.
The average thickness of the coating film is preferably 600 μm or less, more preferably 550 μm or less, particularly preferably 500 μm or less. If the average film thickness of the coating film is below the above-mentioned upper limit, defects such as coating film cracking during drying tend to be less likely to occur.
Here, the average film thickness of the coating film is the value after drying, and is the average value of the film thicknesses at 20 randomly selected locations on the coating film.
The above upper and lower limits can be arbitrarily combined.

The value obtained by dividing the average particle diameter (μm) of the transparent beads (B) by the average film thickness (μm) of the coating film (hereinafter referred to as "average particle diameter/average film thickness of the coating film") is 0.1 or more. is preferable, and 0.2 or more is more preferable. The average particle diameter of the transparent beads (B)/average film thickness of the coating film is preferably 3 or less, more preferably 2 or less.
When the average particle diameter of the transparent beads (B)/average film thickness of the coating film is within the above-mentioned range, a coating film with higher brightness can be obtained.
The reason why a coating film with higher brightness can be obtained is that when the value of the average particle diameter of the transparent beads (B)/average film thickness of the coating film is within the above range, the light that hits the coating film surface is This is thought to be because it is difficult to cause diffused reflection inside the paint film, making it easier to sense the reflected light from the pigment (E) inside the paint film.

<Effect>
According to the coating composition described above, a coating film with high brightness and excellent flip-flop properties and surface smoothness can be formed.
The reason why the coating film has excellent flip-flop properties is that the inclusion of transparent beads (B) in the coating composition allows the pigment (E) to be randomly oriented with respect to the base material when it is formed into a coating film. I can think about it. It is thought that because the pigment (E) is randomly oriented, the direction of the light that hits the surface of the pigment (E) and is reflected becomes random, and as a result, the reflected light can be sensed even if the viewing angle is changed. It is thought that by being able to detect more reflected light in this way, it appears to have higher brightness than conventional product coatings.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.
"Part" means "part by mass.""%" means "% by mass" unless otherwise specified.

<Materials used>
Resin emulsion: Acrylic resin emulsion, Primal AC38, manufactured by Dow Chemical Company, solid content 50%.
Colloid-forming substance: 4% aqueous solution of nonionic guar gum derivative, MEYPRO HPG 8111, manufactured by DuPont.
Pigment 1: FANTASPEARL 1060YR, mica pearl pigment, manufactured by Nihon Koken Kogyo Co., Ltd., average particle size: 23 μm.
Pigment 2: Metashine 1030PS, glass flake pigment, manufactured by Nippon Sheet Glass Co., Ltd., average particle size 25 μm.
Pigment 3: Metashine 2080GP, glass flake pigment, manufactured by Nippon Sheet Glass Co., Ltd., average particle size 80 μm.
Pigment 4: Metashine 5230PS, glass flake pigment, manufactured by Nippon Sheet Glass Co., Ltd., average particle size 230 μm.
Pigment 5: Metashine 5480PS, glass flake pigment, manufactured by Nippon Sheet Glass Co., Ltd., average particle size 480 μm.
Dispersant: Orotane 731, anionic polymer dispersant, manufactured by Dow Chemical Company.
Gelling agent: 5% aqueous solution of ammonium biborate, manufactured by Yoneyama Chemical Industry Co., Ltd.
Extender pigment: 4% aqueous dispersion of hydrated magnesium silicate, Talc SSS, manufactured by Nippon Talc Co., Ltd.
CMC-Na: 1% aqueous solution of sodium carboxymethylcellulose, CMC-1170, manufactured by Daicel Chemical Industries.

Transparent beads 1: Acrylic beads, GB-05S, manufactured by Aica Kogyo Co., Ltd., average particle size 5 μm.
Transparent beads 2: Acrylic beads, GR-400T, manufactured by Negami Kogyo Co., Ltd., average particle size 15 μm.
Transparent beads 3: Acrylic beads, GM-2801, manufactured by Aica Kogyo Co., Ltd., average particle size 28 μm.
Transparent beads 4: Acrylic beads, GM-4003, manufactured by Aica Kogyo Co., Ltd., average particle size 40 μm.
Transparent beads 5: Acrylic beads, GM-9005, manufactured by Aica Kogyo Co., Ltd., average particle size 85 μm.
Transparent beads 6: Acrylic beads, SE-090T, manufactured by Negami Kogyo Co., Ltd., average particle size 110 μm.
Transparent beads 7: Acrylic beads, MR-260IBS, manufactured by Soken Chemical Co., Ltd., average particle diameter 260 μm.
Algaecide: HF-260K, manufactured by Nagase ChemteX, active ingredient 30%.
Antifungal agent: ACTICIDE OTW, manufactured by THOR JAPAN, active ingredient 30%.
Ultraviolet absorber: Tinuvin 400DW, manufactured by BASF JAPAN, active ingredient 40%.
Thickener: Alkali-soluble thickener, SN Thickener 636, manufactured by Sannopco, active ingredient 30%.

<Production of resin particle (A) dispersions A-1 to A-12>
A resin emulsion and a hydrophilic colloid solution were mixed according to the formulation shown in Table 1 to obtain a mixed solution (d). Further, according to the formulation shown in Table 1, water, pigment, and dispersant were mixed to obtain a mixed solution (e). Next, the mixed liquid (d) and the mixed liquid (e) were mixed to obtain a water-based paint (c).
Separately, a gelling agent, water, extender pigment, and CMC-Na were mixed according to the formulation shown in Table 1 to obtain an aqueous solution (f).
Next, the water-based paint (c) was added to the aqueous solution (f) while stirring it with a dissolver (manufactured by Nippon Seiki Seisakusho Co., Ltd., rotation speed: 1000 rpm). The mixture was stirred until the average particle diameter of the water-based paint (c) finely divided by stirring became 0.5 mm to 1 cm to obtain a dispersion of resin particles (A).
The average particle diameter of the resin particles (A) was determined by randomly taking out 20 resin particles (A) from the dispersion, measuring the major axis with a caliper, and taking the arithmetic average of each measurement value.
Table 1 shows the content (parts) of the resin particles (A) contained in the dispersion, the solid content (parts) of the resin particles (A), and the content (parts) of the aqueous resin (D) in the resin particles (A). ), proportion (%) of resin particles (A) in 100% dispersion, proportion (%) of solid content of resin particles (A) in 100% dispersion, aqueous resin in 100% resin particles (A) The ratio (%) of (D) and the content (%) of pigment (E) relative to 100% resin solid content in resin particles (A) are shown. Here, the content of the resin particles (A) is the total amount of the water-based paint (c) and the solid content of the gelling agent. The aqueous resin (D) in the resin particles (A) is the solid content of the resin emulsion.

<Examples 1 to 19, Comparative Examples 1 to 7>
(Manufacture of paint composition)
According to the formulation shown in Tables 2 to 4, resin particle (A) dispersion, resin emulsion, transparent beads, algae-proofing agent, mold-proofing agent, ultraviolet absorber, thickener, 25% ammonia water and water are mixed and painted. A composition was obtained.
Tables 2 to 4 show the resin solid content (parts) in the dispersion medium (C), the ratio (%) of transparent beads (B) to 100% of the aqueous resin (F), and the relationship between resin particles (A) and dispersion medium (C). The ratio (%) of resin particles (A) to the total of 100% is shown. Here, the dispersion medium (C) is the remainder after removing the resin particles (A) and transparent beads. The water-based resin (F) is the solid content of the resin emulsion blended in the production of the coating composition.

(Preparation of painted board)
The obtained coating composition was sprayed onto the surface of a slate board coated with a gray undercoat to a coating amount of 400 g/ ^m2 , and dried at room temperature to form a painted board with a coating film on the surface. I got it.
Regarding the formed coating film, cross sections of the coating film at 10 randomly selected locations were observed with a digital microscope (VHX-8000, manufactured by Keyence Corporation) to measure the film thickness, and each measured value was calculated as an arithmetic average. By doing this, the average film thickness was determined. In addition, the value of average particle diameter of transparent beads (B)/average film thickness of coating film was calculated. The results are shown in Tables 2-4.

(evaluation)
The coating film of the prepared painted board was visually observed, and the brightness, flip-flop properties, and surface smoothness were evaluated using the following criteria. The results are shown in Tables 2 to 4.

- Brightness 1: The brightness (shine) of the coating film is very strong.
2: The brightness (shine) of the coating film is strong.
3: A sense of brightness (shine) can be felt in the coating film, which is good.
4: Feel the brightness (shine) of the paint film.
5: The brightness (shine) of the coating film is weak and no brightness is felt.

・Flip-flop property 1: Even if the viewing angle is changed, the brightness of the coating remains unchanged and is very good.
2: Even when the viewing angle is changed, the brightness of the coating film does not change much and is good.
3: When the viewing angle is changed, the brightness of the coating film is sometimes strong and sometimes weak, but the difference is small.
4: When the viewing angle is changed, the brightness of the coating film is sometimes strong and sometimes weak, and the difference is very large.

・Surface smoothness 〇: Smooth and good coating film appearance.
△: The appearance of the paint film is smooth when viewed from a distance, but unevenness is felt when viewed up close.
×: There are irregularities and the appearance of the coating film is poor.

The coating films of the coating compositions of Examples 1 to 19 were excellent in brightness, flip-flop properties, and surface smoothness.
On the other hand, in the coating film of the coating composition of Comparative Example 1, the pigment (E) content was less than 14% by mass based on 100% by mass of the resin solid content in the resin particles (A), and the transparent beads (B ), the sense of brightness was poor.
The coating films of the coating compositions of Comparative Examples 2 and 3 did not contain the transparent beads (B), and therefore had poor brightness or flip-flop properties.
The coating film of the coating composition of Comparative Example 4 had poor brightness because the content of the pigment (E) was less than 14% by mass based on 100% by mass of the resin solid content in the resin particles (A). Ta.
The coating film of the coating composition of Comparative Example 5 had poor brightness and flip-flop properties because the average particle diameter of the transparent beads (B) was less than 10 μm.
The coating film of the coating composition of Comparative Example 6 had poor flip-flop properties because the content of the transparent beads (B) was less than 20% by mass based on 100% by mass of the resin solid content in the dispersion medium (C). was.
The coating film of the coating composition of Comparative Example 7 had poor surface smoothness because the content of the transparent beads (B) was more than 135% by mass based on 100% by mass of the resin solid content in the dispersion medium (C). was.

1 Paint composition, 10 Resin particles (A), 11 Droplets, 12 Gelled film, 13 Pigment (E), 20 Transparent beads (B), 30 Dispersion medium (C)

Claims (4)

A coating composition comprising resin particles (A), transparent beads (B), and a dispersion medium (C) in which the resin particles (A) and the transparent beads (B) are dispersed,
The resin particles (A) include droplets containing a water-based paint and a gelled film covering the surface of the droplets,
The aqueous paint includes an aqueous medium, an aqueous resin (D), and a glittering pigment (E) dispersed in the aqueous medium,
The content of the pigment (E) is 14% by mass or more based on 100% by mass of the aqueous resin (D),
The dispersion medium (C) includes an aqueous medium and an aqueous resin (F),
The content of the transparent beads (B) is 20 to 135% by mass with respect to 100% by mass of the aqueous resin (F),
A coating composition characterized in that the transparent beads (B) have an average particle diameter of 10 μm or more. The coating composition according to claim 1, wherein the pigment (E) is a flat particle. A coating film formed from the coating composition according to claim 1 or 2. The coating film according to claim 3, wherein the value obtained by dividing the average particle diameter (μm) of the transparent beads (B) by the average film thickness (μm) of the coating film is 0.1 or more.

Images