JP2023128912A - Aqueous anticorrosive coating for aerosol, and aerosol product - Google Patents

Abstract

To provide an aqueous coating that serves the purpose of rust prevention but can be aerosolized as needed.SOLUTION: An aqueous anticorrosive coating for aerosol includes aqueous emulsion and anticorrosive metal thin pieces. The aqueous emulsion includes core-shell emulsion. Core-shell particles in the core-shell emulsion each have a hydrophilic shell layer.SELECTED DRAWING: None

Description

The present invention relates to a water-based anticorrosive paint for aerosols and aerosol products.

A paint is a material containing coating components and is used on a target substrate. Although there are paints that do not contain solvents, such as powder paints and solvent-free paints, paints generally contain a solvent as a medium. Water-based paints contain water as a medium, and such paints are spread on a substrate and form a coating film through a drying process.

Paints are often used depending on the purpose. For example, antirust paints are used to prevent corrosion of steel members. In other words, steel members and the like are sometimes subjected to rust prevention treatment using antirust paint.

Japanese Patent Application Publication No. 2-311514 Japanese Patent Application Publication No. 2016-510082 Japanese Patent Application Publication No. 2003-82294

The inventor of the present application noticed that there were still problems to be overcome with conventional anticorrosive paints, and found it necessary to take measures to solve the problem. Specifically, we found the following issues.

Even if water-based anticorrosive paints exhibit desired anticorrosive properties as a coating film, the coating efficiency cannot be said to be sufficient when applied using a brush, roller, or the like. In addition, rust prevention work using such painting tools often requires bulky tools, and it cannot be said that the burden on the painter is light.

Therefore, although it is conceivable to use a water-based anticorrosion paint as an aerosol product, it has been recognized by those skilled in the art that this would normally be difficult. This is because an aqueous emulsion exhibiting anti-rust performance is difficult to stabilize over time even when mixed with a propellant used in an aerosol (for example, a hydrocarbon material such as dimethyl ether). Specifically, when mixed with such a propellant, the emulsion particles may dissolve over time and promote gelation. As described above, in the paint industry, it has been generally considered difficult to convert aqueous emulsions primarily intended for rust prevention into aerosols as desired.

The present invention has been made in view of this problem. That is, the main object of the present invention is to provide a water-based paint that is particularly intended for rust prevention and that also contributes to desired aerosolization.

The inventor of the present application attempted to solve the above problem by tackling the problem in a new direction rather than by extending the conventional technology. As a result, an aqueous anticorrosive paint was invented that achieved the above main objective.

The present invention provides a water-based anti-corrosion paint for aerosol, comprising:
comprising an aqueous emulsion and a corrosion-resistant metal flake,
There is provided an aqueous anticorrosive paint for aerosol spraying, which includes a core-shell emulsion as the aqueous emulsion, and the core-shell particles in the core-shell emulsion have a hydrophilic shell layer.

According to the present invention, a water-based rust-preventing paint that is particularly intended for rust prevention and that contributes to desired aerosolization is provided.

More specifically, the water-based anticorrosive paint according to the present invention can be provided as an aerosol product that is stable over time even when used together with a propellant such as a hydrocarbon material.

In the following, the "aqueous anticorrosive paint for aerosol" and the "aerosol product" according to the present invention will be explained in more detail. However, more detailed explanation than necessary may be omitted. For example, detailed explanations of well-known matters or redundant explanations of substantially the same configurations may be omitted. This is to avoid unnecessary redundancy in the explanation and to facilitate understanding by those skilled in the art. Note that the forms described below are for explaining the technical idea of the present invention, and are not intended to specifically limit the present invention.

The various numerical ranges mentioned herein are intended to include the lower and upper numerical limits themselves, unless specific terms such as "less than" or "more than/greater than" are used. In other words, if we take a numerical range from 1 to 10 as an example, it can be interpreted as including the lower limit of "1" and also the upper limit of "10". Also, the terms "about" and "extent" are meant to include variations of several percentages, such as ±10%.

[Findings that formed the basis of the present invention]

Steel members are treated with anti-rust coating to prevent corrosion. Among them, bridges, steel towers, ships, and offshore structures are used in highly corrosive environments and require long-term rust prevention, so they are regularly repainted. In such cases, it is often a large-scale construction work that requires the installation of scaffolding and a large number of people.

Minor repairs may be required for damaged paint films and parts discovered during inspections of parts and equipment and during surveys of paint film deterioration. In this case, due to the nature of the work and space constraints, it may be possible to carry out simpler repair painting.

Conventionally, epoxy resin-based paints have been widely used to prevent rust on steel members. This is because epoxy resin has excellent adhesion to steel materials, and the cured coating film blocks external corrosion factors and contributes to rust prevention of steel members. When new steel members are installed, they are controlled and painted in a painting shop with an open space such as a dockyard. However, once the steel members are assembled, a closed space is formed inside the steel member like a box girder, so rainwater tends to collect in the closed space and cause corrosion. For example, after installation, the steel members of long offshore bridges such as the Akashi Bridge are regularly inspected for corrosion and damage to the paint film, and plans are made for repair work. If corroded areas or deteriorated areas of the paint film are found during the inspection, repairs may be made on the spot depending on the extent of the damage. For such repairs, it is preferable to use epoxy resin paint in consideration of adhesion to steel materials and anti-corrosion properties for the reasons mentioned above, but epoxy paints contain large amounts of organic solvents for the purpose of dissolving resin components. . In other words, there is a concern that the organic solvent contained in the paint will volatilize during painting, and the closed space will be filled with the organic solvent. This also applies to other anti-rust repairs. For example, epoxy resin paint is often used for repair painting in closed spaces, such as ships, railway cars, containers, and vehicle loading platforms. can be filled with organic solvents.

Volatilized organic solvents often contain harmful aromatic hydrocarbons such as ethylbenzene, xylene, and toluene, and there are concerns that these may induce neurological disorders and cancer. Therefore, when performing painting work, it is mandatory to install exhaust equipment and use protective gear such as an organic gas gas mask or an air supply mask according to the Specified Chemical Substance Hazard Prevention Regulations and the Organic Solvent Poisoning Prevention Regulations. However, since many bridges are located at high places or on the sea, it is generally difficult to transport and install exhaust equipment in closed spaces. In addition, it can be difficult to wear a respirator because there are stairs and ramps that lead to closed spaces. Although it is only possible to wear a gas mask for organic gases, the amount of time the canister can be used is limited, which limits the amount of time you can stay in a closed space. Furthermore, since the work involves working at heights, there are limits to the ability to bring spare absorption canisters.

In view of these circumstances, the inventors of the present application have developed a water-based paint that is designed to prevent rust, but is also safer. Such paints are water-based paints that, while providing the desired anticorrosive properties, do not fall under various preventive regulations, especially when used in confined spaces. In other words, it is a water-based anti-rust paint that does not contain any specific chemical substances in its raw materials and is designed with worker safety in mind.

Although the water-based anti-rust paint developed by the present inventors can exhibit the desired anti-rust performance (for example, anti-rust performance comparable to organic solvent-based anti-rust paint), When it comes to painting with aerosol type, the work efficiency is not as high as that of an aerosol type. Furthermore, in the case of brushes, rollers, etc., the burden increases in terms of painting tools and accessories that must be brought to the site. On the other hand, since it was recognized that aqueous emulsions would initially be difficult to convert into aerosols, which would increase work efficiency, no full-scale study was conducted. In other words, water-based emulsions are difficult to mix with propellants used in aerosols, such as hydrocarbons such as dimethyl ether, and the anti-corrosion components of paints have an adverse effect on stabilizing emulsion particles. It was thought that when mixed with the emulsion particles, the emulsion particles would dissolve over time and become easier to gel. In other words, in the actual paint industry, water-based emulsion paints with desired anti-corrosion properties (especially water-based emulsion paints that can be used more safely in closed spaces) are required to suitably meet the aging requirements and be aerosolized as desired. etc. were difficult.

[Water-based antirust paint of the present invention]
The paint of the present invention is a water-based antirust paint. Preferably, the coating of the present invention is a water-based anticorrosive coating for aerosols (ie, "aerosol products"). In other words, it is a water-based anti-rust paint suitable for use in aerosol injection (hereinafter, the water-based anti-rust paint for aerosol is also referred to as "aqueous anti-rust paint for aerosol injection"). In the present invention, an aqueous emulsion is used as the rust-preventing paint, and no organic solvent is used to dissolve the coating resin components. Therefore, the paint of the present invention is a rust-preventing paint that avoids the phenomenon that the organic solvent in the paint evaporates during painting. In other words, it is possible to avoid the phenomenon in which the above-mentioned "closed space" or the like is filled with organic solvent, and the operator can carry out the rust prevention treatment more safely.

In the present invention, "aerosol" refers to a mode in which the contents of a container are discharged (preferably discharged in the form of mist and/or foam) using the pressure of a propellant (e.g., propellant gas) or such discharge. Refers to a product or structure that can be used.

The aqueous anticorrosive paint for aerosol spraying of the present invention comprises an aqueous emulsion and a corrosion-resistant metal flake, and one of its features is that the aqueous emulsion includes a core-shell emulsion.

In the present invention, the term "core-shell emulsion" means that at least one of the particles forming the emulsion has a core-shell structure. That is, the water-based anticorrosive paint of the present invention is a paint containing an aqueous emulsion, and the aqueous medium of the emulsion contains particles having a core-shell structure. To put it simply, it can be said that in the aqueous anticorrosive paint of the present invention, the core-shell particles form an aqueous emulsion.

The water-based paint for aerosol spraying of the present invention is a rust-preventing paint that exhibits rust-preventive properties in that it contains at least corrosion-resistant metal flakes. In particular, the paint for aerosol spraying according to the present invention contains corrosion-resistant metal flakes and also contains a core-shell emulsion as an aqueous emulsion, making it more suitable as a rust-preventing paint for aerosol spraying.

This corrosion-resistant metal flake is a flake body made of a metal material having corrosion resistance. The corrosion-resistant metal flakes may be included as one or more flakes in the water-based anticorrosive paint. Preferably, a plurality of corrosion-resistant metal flakes are included in the water-based rust-inhibiting paint, thereby providing the paint with more favorable rust-inhibiting properties.

In this specification, "corrosion resistance" refers to resistance to corrosive action in a broad sense, and in a narrow sense, it refers to resistance to corrosive action in the environment of a water-based paint and/or a coating film obtained from the water-based paint. It means to endure. "Resistance to corrosion" means, for example, not only the state in which the metal itself is resistant to corrosion, but also the state in which the metal forms a passive film on its surface, making it resistant to corrosion. . In addition, in this specification, "thin piece" in a broad sense refers to a shape in which the thickness dimension is smaller than the main surface dimension (for example, the main surface dimension is such that the overall shape of the metal material is flat or plate-like). In a narrow sense, the main surface dimension (for example, the maximum value of the main surface dimension in the direction perpendicular to the thickness) is 10 to 5,000 times or 10 to 2,500 times the thickness dimension. , 10 to 1000 times, 10 to 900 times, 20 to 700 times, 30 to 500 times, 40 to 500 times, 50 to 500 times, 50 to 400 times, 50 to 300 times, or 50 to 200 times. It means. In certain preferred embodiments, the flakes may have a thickness on the micron or nanometer order, such as 0.01-8 μm, 0.01-5 μm, 0.01-2 μm, 0.05-1 μm, 0.1~1μm. It may have a thickness such as 0.1-0.9 μm, 0.1-0.7 μm, or 0.1-0.5 μm (thickness here refers to the maximum thickness of a single flake). ). Due to the "flakes", the corrosion-resistant metal flakes may be flexible. That is, the corrosion-resistant metal flake may be a flexible corrosion-resistant metal material.

The "thickness dimension" of a corrosion-resistant metal flake is measured using an observation means such as an optical microscope, a scanning electron microscope (SEM), or a transmission electron microscope (TEM) on a paint or a coating film obtained from it. An arithmetic mean value obtained by averaging the maximum values at four arbitrary points on each of three arbitrary thin slices may be used. Similarly, the "principal surface dimensions" of a corrosion-resistant metal flake can be determined by observing the paint or the coating film obtained from it using an optical microscope, scanning electron microscope (SEM), or transmission electron microscope (TEM). The arithmetic mean value obtained by averaging the maximum principal surface dimensions of each of the three arbitrary thin sections may be used.

The corrosion-resistant metal flakes used in the present invention are not particularly limited, but can be obtained by processing a thin metal material, such as a metal foil made of the following corrosion-resistant metals, into fine flakes and/or particles. be able to. For example, it can be obtained by subjecting a thin metal material such as metal foil to a mechanical process that applies shearing force, such as cutting or crushing, and/or a chemical process, if necessary. Furthermore, commercially available corrosion-resistant metal flakes may be used.

In the present invention, a plurality of corrosion-resistant metal flakes may be oriented so as to be stacked on top of each other in the thickness direction within the coating. Therefore, components such as water, oxygen, and/or various ions that cause deterioration of the substrate (hereinafter also referred to as "deterioration components") are effectively prevented from reaching the substrate, and the corrosion of the substrate is effectively prevented. can be reduced or suppressed. In certain preferred embodiments, the lamination of the corrosion-resistant metal flakes may provide the coating with a labyrinth structure of the corrosion-resistant metal flakes. The term "labyrinth structure" used here refers to a complex structure that is so-called "labyrinth-like". It refers to a complex meandering shape due to its shape.

The corrosion-resistant metal flake may be, for example, a metal flake made of at least one member selected from the group consisting of stainless steel, aluminum alloy, titanium alloy, and nickel alloy. Such a metal flake exhibits corrosion resistance, and due to the above-mentioned lamination, it can contribute more favorably to reducing corrosion of the base material. Note that "stainless steel" in this specification is not particularly limited, but may be, for example, chromium defined in "JIS G 0203 Steel Terminology" or alloy steel containing chromium and nickel.

The corrosion-resistant metal flake used in the water-based paint for aerosol spraying of the present invention may be in the form of a metal foil. Having such a thinner morphology makes it easier for the flakes to stack on top of each other in the coating, making it easier to create a labyrinth structure of corrosion-resistant metal flakes. More specifically, the corrosion-resistant metal foil may be at least one foil selected from the group consisting of stainless steel foil, aluminum alloy foil, titanium alloy foil, and nickel alloy foil.

For example, the corrosion-resistant metal flake may have an elongated overall shape (particularly the main surface shape). Expressed from another perspective, the corrosion-resistant metal flake may have a shape such as an elongated linear shape that is straight or curved. Regarding this, for example, the aspect ratio of a corrosion-resistant metal flake, for example, the ratio of the maximum dimension on the main surface of the flake in the direction perpendicular to the thickness direction and the dimension perpendicular to it (maximum dimension / "dimension in the direction perpendicular to the maximum dimension") is 2 or more and 30 or less, 2 or more and 20 or less, 2 or more and 15 or less, 2 or more and 10 or less, 2 or more and 5 or less, 2 or more and 4 or less, 2 or more and 3 or less, 1.5 or more and 3 or less, 1.5 or more and 2.5 It may be as follows.

In some preferred embodiments, the corrosion resistant metal flakes are scaly stainless steel foils. The scaly stainless steel foils tend to laminate at least partially to each other within the coating in the direction of its thickness so as to provide the coating with a labyrinth structure. In other words, a labyrinth structure is particularly likely to be formed in the coating film with the scale-like stainless steel foil. Therefore, if scaly stainless steel foil is included as a corrosion-resistant metal flake, the supply of water, oxygen, and/or various ions to the substrate, which cause deterioration, can be more effectively blocked and reduced, which is more suitable. It is possible to reduce and suppress corrosion of the base material. Here, "scaly" refers to a form having flat, scale-like pieces (thin flakes). As long as the paint film contains something that can be recognized as a "scale shape" by a person skilled in the art based on the image of the "corrosion-resistant metal flakes" (for example, a single shape of the corrosion-resistant metal flakes), it is considered "scaly". It may be considered.

The stainless steel foil (e.g. flaky stainless steel foil) may be a mixture of elongated or linear stainless steel foil and other stainless steel foils such as non-elongated or non-linear stainless steel foil. . In such a case, long or linear stainless steel foils can easily fill the gaps between other stainless steel foils that are not in such a shape, and corrosion reduction of the substrate can be further promoted.

The type of stainless steel used as the material for the scale-like stainless steel foil is not particularly limited. It may be a corrosion-resistant metal scale made of a known stainless steel material. For example, the stainless steel is at least one type selected from the group consisting of ferritic stainless steel, austenitic stainless steel, martensitic stainless steel, two-phase stainless steel (for example, austenitic-ferritic stainless steel), and precipitation hardening stainless steel. It may be. In particular, if higher corrosion resistance and higher workability are important, it is preferable to use ferritic stainless steel and/or austenitic stainless steel. As the ferritic stainless steel, for example, SUS430 can be mentioned. Further, examples of austenitic stainless steel include SUS304, SUS316 and/or SUS316L. Note that stainless steel may contain unavoidable impurities, and the specific components of such unavoidable impurities are not particularly limited as long as the effects of the present invention are achieved. In terms of providing more suitable corrosion resistance and processability, the content of unavoidable impurities in the scale-like stainless steel foil may be 1% by weight or less.

The scale-like stainless steel foil may have a 50% particle diameter (hereinafter also referred to as "Dp50"), which corresponds to the flake diameter that is 50% in the cumulative distribution, of 10 μm or more and 300 μm or less, for example, 20 μm or more and 50 μm or less, or It may be 20 μm or more and 40 μm or less. Further, the scale-like stainless steel foil may have a thickness of 0.1 μm or more and 5 μm or less, for example, 0.1 μm or more and 1 μm or less, 0.1 μm or more and 0.8 μm or less, and 0.1 μm or more and 0.6 μm or less. , 0.2 μm or more and 3 μm or less, or 0.2 μm or more and 1 μm or less. In addition, the scale-like stainless steel foil has its aspect ratio, for example, the ratio of the maximum dimension on the main surface of the flake in the direction perpendicular to the thickness direction and the dimension perpendicular to it (maximum dimension / "dimension in the direction perpendicular to the maximum dimension"). ) may be 1 to 20, for example 2 to 15, 2 to 10, or 2 to 5, 2 to 4, 2 to 3, 1.5 to 3, 1.5 to 2 It may be less than or equal to .5. When such a scale-like stainless steel foil is included in a paint, a labyrinth structure can be more stably provided in the resulting paint film. In other words, with the scale-like stainless steel foil, it becomes easier to obtain a coating film exhibiting superior rust prevention performance. Furthermore, when the corrosion-resistant metal flakes are scaly stainless steel foils, it becomes easier to improve the impact resistance, abrasion resistance, thermal stability, and/or chemical resistance of the coating film.

The aqueous anticorrosive paint for aerosol injection of the present invention contains the above-mentioned corrosion-resistant metal flakes as a rust preventive material, and the aqueous emulsion contained as a vehicle is a core-shell emulsion.

A core-shell emulsion is an emulsion in which particles as a dispersoid have a core (particle inner core) and a shell layer (particle outer shell). In the present invention, since the emulsion is an aqueous emulsion, dispersoids (dispersoid particles) having a core and a shell layer are dispersed in water contained as a dispersion medium. That is, in the paint of the present invention, particles (film-forming particles) composed of a core and a shell surrounding at least a part of the core in an aqueous medium such as purified water, deionized water, distilled water, and/or ion-exchanged water. are dispersed. A plurality of such film-forming particles are dispersed to form an emulsion. Since the paint of the present invention contains corrosion-resistant metal flakes, it can be said that the water-based rust-preventive paint containing the corrosion-resistant metal flakes contains core-shell particles as dispersoid particles in its emulsion. In the present invention, "core-shell particles" in a broad sense refers to an embodiment in which particles constituting an emulsion can be considered to be divided into an inner region including the center and an outer shell region. . In a narrow sense, "core-shell particles" refer to particles constituting an emulsion in which the inner region (core) containing the center of the particle and the outer shell region (shell layer) surrounding that region have different components, functional groups, and molecular weights ( (weight average molecular weight and/or number average molecular weight), glass transition temperature (Tg), and/or material, etc.

If the emulsion is a core-shell emulsion, the shell layer may have the function of protecting the core, so even if it contains corrosion-resistant metal flakes, it will not be affected by the effects of corrosion-resistant metal flakes and/or the effects of aerosolization. In contrast, suitable emulsion resistance can be easily obtained. In other words, although the water-based paint of the present invention has corrosion-resistant metal flakes, the core portion of the emulsion-dispersed particles is suitably protected, and it is more effective than propellants used in aerosols (for example, hydrocarbon materials such as dimethyl ether). They can be suitably mixed.

In one preferred embodiment, the core-shell particles in the core-shell emulsion have a hydrophilic shell layer. This facilitates the hydrophilic shell layer to function as a barrier layer against the corrosion-resistant metal flake and/or against the propellant used for aerosolization (eg, a hydrocarbon material such as dimethyl ether). In other words, the hydrophilic shell layer facilitates suitable protection of the core (preferably the particles or particle cores) from corrosion-resistant metal flakes and/or aerosol propellants such as dimethyl ether. In other words, although the water-based anticorrosive paint according to the present invention contains the above-mentioned corrosion-resistant metal flakes as a rust preventive material, due to the core-shell emulsion having a hydrophilic shell layer, the water-based anticorrosive paint contains hydrocarbon materials. Even when used with a propellant such as, the desired aerosolization can be achieved. In this way, the "hydrophilic shell layer" according to the present invention can also be referred to as an aerosol-resistant protective layer or an aerosolized protective layer, since it more suitably protects the emulsion particles as an aerosol product. It can be referred to as an aerosol-resistant protective layer or an aerosolization protective layer in a paint containing (aqueous paint).

The hydrophilic shell layer may retain water to form a water film. When used as an aerosol, the paint may be diluted with water. Here, even if a general aqueous emulsion is diluted with water, the emulsion particles themselves do not substantially contain or hardly contain water, but when diluted, the particles of a core-shell emulsion with a hydrophilic shell layer absorb more water. It becomes easier to hold the emulsion particles in a suitable manner, and as a result, it becomes easier to form a water film barrier layer in the emulsion particles. Therefore, the particle cores can be better protected from corrosion-resistant metal flakes and/or aerosol propellants such as dimethyl ether. Without wishing to be bound by any particular theory, it is believed that the water film of the shell can act as if it were a cushion layer, creating a barrier to corrosion-resistant metal flakes and/or aerosol propellants (i.e., an anti-aerosol or aerosolized protective film). etc.). Similarly, without being bound by any particular theory, regarding resistance to dimethyl ether, since dimethyl ether is hydrophobic, repulsion tends to occur between dimethyl ether and the hydrophilic shell layer, which causes the particle core to It is also inferred that this is a contributing factor to conservation. Thus, in a preferred embodiment, the hydrophilic shell layer of the core-shell particles in the core-shell emulsion retains water and forms a water film, which can provide more suitable emulsion stabilization.

Although the paint of the present invention is only a water-based anticorrosive paint, it is a paint that contributes to more suitable aerosolization. In particular, due to the hydrophilic shell layer, it is possible to exist more stably over time as an aerosol product, even though it is a water-based anticorrosive paint containing corrosion-resistant metal flakes. Corrosion-resistant metal flakes have higher strength by themselves and can have a more or less persistent effect on the emulsion particles. In particular, in the presence of propellants that are packaged in liquefied or compressed gas form with water-based anticorrosion paints, corrosion-resistant metal flakes under such pressure are likely to act adversely on the emulsion particles (i.e., prevent aerosol products from forming). Corrosion-resistant metal flakes in the water-based paint can have a particularly adverse effect on the emulsion particles if there is a propellant packed in a container to achieve the desired effect and the water-based rust-inhibiting paint is under pressure in the container. ). In the present invention, since the core-shell particles have a hydrophilic shell layer, this hydrophilic shell layer can act to counteract the above-mentioned negative effects of the corrosion-resistant metal flakes, and the aqueous emulsion can become more stable over time. In other words, stable aerosolization over time can be achieved even though the paint is a water-based anticorrosive paint. This means that water-based anti-rust paints exhibit better long-term storage properties as anti-rust aerosol products, even when packed together with a propellant for aerosolization. This can be said to be a particularly advantageous effect in view of the intended use.

In the present invention, the shell layer may be made hydrophilic by containing a hydrophilic group. In a preferred embodiment, the shell layer contains a functional group that exhibits hydrophilicity in water. For example, nonionic hydrophilic groups, cationic hydrophilic groups, anionic hydrophilic groups and/or amphoteric hydrophilic groups may be included in the shell layer. Although this is just one example, the emulsion particles may be configured such that the shell layer contains an anionic hydrophilic group. When such a functional group that exhibits hydrophilicity in water is contained, the hydrophilic shell layer of the core-shell particles of the aqueous emulsion that coexists with the corrosion-resistant metal flakes in the aqueous anticorrosive paint tends to be more suitable, and the desired aerosolization can be achieved. This makes it easier to produce a more stable emulsion. For example, the shell layer may contain at least one functional group selected from the group consisting of amino groups, carboxylic acid groups, sulfonic acid groups, and phosphoric acid groups. Such hydrophilic groups in the shell layer can be determined through conventional elemental analysis techniques. For example, the presence of the hydrophilic group in the shell layer can be confirmed using an absorption photometer (for example, IR7000 model manufactured by JASCO Corporation). That is, the hydrophilic shell layer can be determined by optical analysis using an absorptiometer or the like through sampling from the water-based anticorrosive paint or the coating film obtained therefrom.

In one preferred embodiment, the hydrophilic shell layer is a hydrophilic polymer shell and the particle core is a hydrophobic polymer core. That is, the emulsion particles may be particles in which the outer shell of the particles is a hydrophilic polymer that at least partially or completely surrounds a hydrophobic polymer. In such an embodiment, as described above, the hydrophilic polymer shell layer more easily forms a water film barrier layer when the paint is used as an aerosol liquid, and is suitable for use with aerosol propellants such as dimethyl ether and/or corrosion resistance. The particle cores can be better protected from metal flakes. In other words, even when the aqueous anticorrosive paint according to the present invention is used as an aerosol liquid, the phenomenon of dissolution and gelation of emulsion particles is suitably suppressed, and as a result, a desired aerosol product can be obtained.

For example, the shell layer of the core-shell particle may be a layer in which a base material component and a component exhibiting ionicity that acts as a counter to the ionicity exhibited by the base material component coexist. For example, the shell layer of the core-shell particle may be a layer in which a base polymer and a polymer that can have ionicity that counters the ionicity that the base polymer can have coexist. In such a case, it can be said that the base polymer and the counterionic polymer (or "counter ion" or a polymer containing it) coexist in the particle shell, and therefore, in one preferred embodiment, the base polymer and the counterionic polymer (or "counter ion" or a polymer containing it) coexist. Emulsions having both anionic and cationic components (briefly "ampholytic emulsions") can be produced. For example, the base polymer of the shell base may be anionic, and the shell layer may be comprised of a layer in which polymer moieties or polymers that may be cationic are dispersed in the base polymer. Alternatively, the shell layer may be composed of a layer in which the base polymer serving as the shell base can exhibit cationic properties, and polymer sites or polymers that can exhibit anionic properties are dispersed in the base polymer. In an aqueous emulsion composed of core-shell particles having such a shell layer, the particle cores are more easily protected from aerosol propellants such as dimethyl ether and/or corrosion-resistant metal flakes. In other words, even if the aqueous anticorrosive paint according to the present invention is used as an aerosol liquid, the phenomenon of dissolving and gelling the emulsion particles can be easily suppressed, and as a result, the desired aerosol product can be easily obtained. Become.

The hydrophilic polymer shell layer may be comprised of a polymer having a lower molecular weight than the polymer core. For example, the hydrophilic polymer shell layer has a molecular weight of 1/1000 to 1/5, 1/100 to 1/5, or 1/100 to 1/10 that of the polymer core (e.g., hydrophobic polymer core). It may be composed of a small amount of polymer. In other words, in the core-shell particles, the molecular weight of the polymer core (weight average molecular weight Mw) is 5 to 1000 times, 5 to 100 times the molecular weight (weight average molecular weight Mw) of the hydrophilic polymer shell layer, or It may be 10 times to 100 times, etc. (in some embodiments, it may be 10 times to 70 times, 10 times to 60 times, 20 times to 60 times, 30 times to 60 times, 40 times to 60 times, etc.) good). Expressed from another perspective, the shell is composed of a relatively low molecular weight polymer with a molecular weight of about 5,000 to 40,000 (for example, 5,000 to 30,000, 5,000 to 25,000, 10,000 to 30,000, 10,000 to 25,000, or 5,000 to 20,000). while the molecular weight is 50,000 or more (for example, 50,000 to 4,000,000, 50,000 to 3,000,000, 50,000 to 2,000,000, 50,000 to 1,500,000, 100,000 to 1,500,000, 300,000 to 1,500,000, 500,000 to 1,500,000, 75,000 0 to 1,500,000 or 750,000 to 1,250,000) comparison A polymer of relatively high molecular weight may constitute the core. In an aqueous emulsion composed of core-shell particles having such a molecular weight or such a molecular weight relationship, the particle cores are more likely to be protected from aerosol propellants such as dimethyl ether and/or corrosion-resistant metal flakes. In other words, even if the aqueous anticorrosive paint according to the present invention is used as an aerosol liquid, the phenomenon of dissolving and gelling the emulsion particles can be easily suppressed, and as a result, the desired aerosol product can be easily obtained. Become.

In addition, "molecular weight" as used in this specification may be regarded as a weight average molecular weight (Mw), and may be regarded as a weight average molecular weight measured by GPC under the following conditions (in other words, what is simply stated as "molecular weight") may be considered the “weight average molecular weight”).

<GPC measurement of molecular weight (weight average molecular weight Mw)>
Equipment manufacturer: Japan Waters Co., Ltd. Equipment name: Alliance e2695
Column: Shodex KF-606M
Column temperature: 40℃
Mobile phase: THF (reagent grade)
Flow rate: 0.5mL/min
Sample injection volume: 5.0μL

Although the hydrophilic polymer shell layer and the hydrophobic polymer core are not particularly limited, they may be bonded to each other by, for example, a crosslinked structure. That is, the polymer of the core portion and the polymer of the shell portion may be bonded to each other via elements (eg, atoms, elements, and/or molecules, etc.) that are different from the base material constituent elements. In other words, a core-shell emulsion may be formed in which the core and shell are bonded to each other by adding a crosslinking agent. Having such a crosslinked structure can further improve the integrity of the core-shell particles. In the above example, for example, the shell portion contains a relatively low molecular weight polymer with a molecular weight of about 5,000 to 40,000 as mentioned above, and the core portion contains a relatively high molecular weight polymer of about 50,000 to 4,000,000 as mentioned above. and a molecular weight polymer, which may be bonded to each other by a crosslinking element/component. The crosslinking element or crosslinking agent is not particularly limited, but may contain a highly reactive functional group (a functional group highly reactive during the polymerization reaction of emulsion particles), for example, The monomer may be a monomer containing a functional group (for example, it may be a monomer containing an amino group and/or a glycidyl group or a vinyl monomer). In one embodiment, the crosslinking agent corresponds to a glycidyl group-containing vinyl monomer such as glycidyl (meth)acrylate, and the core portion and the shell portion are bonded via the glycidyl group-containing vinyl monomer such as glycidyl (meth)acrylate. The emulsion particles may have a structure in which these are bonded to each other.

Regarding core-shell particles, the mass ratio of the polymer constituting the shell part and the polymer constituting the core part is not particularly limited, but may be 1:9 to 9:1 (shell part: core part), For example, the ratio may be 2:8 to 8:2 or 3:7 to 7:3 (shell portion: core portion). In a preferred embodiment, for core-shell particles, the ratio of "the mass of the polymer constituting the core part" to "the mass of the polymer constituting the shell part" (i.e., "the mass of the polymer constituting the core part"/"the mass of the polymer constituting the shell part") The "mass of the polymer" is larger than 1. This makes it easier to form a shell layer of the core-shell particles of the water-based emulsion that coexists with the corrosion-resistant metal flakes in the water-based anticorrosion paint, and to achieve the desired aerosolization point. This makes it easier to produce a more stable emulsion.

The size of the core-shell particles of the aqueous emulsion is not particularly limited, and may be any size as long as it contributes to the aqueous emulsion. By way of example only, the average particle diameter of the core-shell particles of the aqueous emulsion may be, for example, 5 to 900 nm, 10 to 900 nm, 10 to 700 nm, 10 to 500 nm, 20 to 500 nm, 50 to 500 nm, or 100 to 500 nm. It may be 900 nm, etc.

The hydrophilic polymer shell may contain nonionic, cationic, anionic and/or amphoteric functional groups and/or polymer components exhibiting hydrophilic properties. Although this is just one example, it may contain, for example, an anionic resin containing at least an anionic functional group. For example, the polymer shell may be constructed from a resin containing at least one anionic functional group selected from the group consisting of amino groups, carboxylic acid groups, sulfonic acid groups, and phosphoric acid groups. Examples of the anionic resin include at least one selected from the group consisting of acrylic resins, urethane resins, acrylic urethane resins, and the like containing the above functional groups. By way of example only, the polymer shell may include, for example, an anionic resin and silicic acid or a salt thereof (for example, a salt with an organic base).

The glass transition temperature (Tg) of the polymer component (i.e. resin component) included in the core-shell emulsion may be between 0°C and 60°C, for example between 10°C and 50°C, between 15°C and 40°C, or between 15°C and 35°C. etc. In such a case, a coating film formed from the water-based anticorrosive paint according to an embodiment of the present invention tends to exhibit better waterproof properties. In core-shell particles, the shell layer and the core may have different glass transition temperatures (Tg), and the shell layer may have a higher Tg than the core. For example, the Tg of the hydrophilic shell layer may be 1.2 to 5 times, 1.2 to 3 times, or 1.2 to 2 times the Tg of the core portion. In an aqueous emulsion composed of such core-shell particles, the particle cores are more easily protected from aerosol propellants such as dimethyl ether and/or corrosion-resistant metal flakes. In other words, even if the aqueous anticorrosive paint according to the present invention is used as an aerosol liquid, the phenomenon of dissolving and gelling the emulsion particles can be easily suppressed, and as a result, the desired aerosol product can be easily obtained. Become.
Note that in this specification, "glass transition temperature (Tg)" may be a value measured in accordance with JIS K 7121.

Further, the minimum film forming temperature (MFT) of the polymer component (i.e., resin component) contained in the core-shell emulsion may be -20°C to 50°C, for example, 0°C to 30°C, 0°C to 20°C, 0°C. It may be between 10°C and 2°C and 8°C. In such a case, the water-based anticorrosive paint according to one embodiment of the present invention tends to exhibit good film-forming properties.

In a water-based anticorrosion paint, the water content is 20% to 60% by weight, such as 30% to 55% by weight, 30% to 45% by weight, or 35% to 45% by weight, based on the total weight of the paint. It may be expressed as mass %. The type of water, ie, the water in the aqueous emulsion, is not particularly limited, and may be, for example, tap water, purified water, deionized water, distilled water, and/or ion-exchanged water. Further, the water of the aqueous emulsion may contain an emulsifier, and there is no particular restriction on the type thereof. Common emulsifiers used in water-based paints may be included. In addition, in the water-based anticorrosive paint of the present invention, the water in the water-based emulsion does not need to contain alcohol or the like. To put it simply, in the present invention, the aqueous emulsion does not need to contain alcohols, glycols, and/or esters as water-miscible polar solvents.

Here, the aqueous core-shell emulsion composed of the core-shell particles of the hydrophilic shell layer can be obtained, for example, by polymerizing the core component surrounded by the shell component in an aqueous phase. Although not particularly limited, a treatment is performed to obtain a hydrophilic polymer or its precursor in the presence of a core component (preferably a monomer of a hydrophobic core component) by polymerization or the like in water. The core component is surrounded by a hydrophilic polymer or its precursor, and then the core component is surrounded by a hydrophilic shell portion in an aqueous medium by subjecting monomers (preferably hydrophobic monomers) of the core component to polymerization. Core-shell particles can be obtained. That is, through such a polymerization process, an aqueous core-shell emulsion composed of core-shell particles of a hydrophilic shell layer can be obtained. The polymerization may be a radical polymerization and therefore a suitable radical polymerization initiator may be used. If necessary, stirring may be performed or an emulsifier may be used to promote emulsification. Further, a crosslinking agent may be included in the aqueous phase to be subjected to the polymerization treatment, and in this case, it becomes easier to obtain a form in which the shell portion and the core portion are bonded more suitably in the emulsion particles. For example, a crosslinking agent may be included in combination with (or mixed with) the core component of the hydrophobic monomer. In addition, when obtaining a shell layer in which a base polymer and a polymer that can have ionicity that is a counter to the ionicity that the base polymer can have coexist, polymerization for forming such shell layer is performed. As the monomers used for this purpose, monomers having such ionic properties may be used.
In the present invention, an aqueous core-shell emulsion composed of core-shell particles of a hydrophilic shell layer is combined with a corrosion-resistant metal foil (e.g., with appropriate agitation), thereby obtaining an aqueous anti-rust coating. The stirring process is not particularly limited, and any stirring/mixing process commonly performed in the paint industry can be employed.
Regarding the aqueous anticorrosive paint of the present invention, emulsions commercially available as core-shell emulsions may be used. In particular, emulsions commercially available as core-shell emulsions may be used as vehicles in the aqueous anticorrosion coatings of the present invention. For example, a commercially available emulsion containing core-shell particles may be used as long as the particle-shell layer exhibits hydrophilicity. In such a case, a water-based anticorrosive paint can be obtained by stirring such an emulsion and a corrosion-resistant metal foil together. Note that the stirring treatment of the aqueous emulsion as a vehicle and the corrosion-resistant metal foil is not particularly limited, and for example, the stirring speed may be about 10 to 3000 rpm and the stirring time may be about 5 minutes to 60 minutes.

In a preferred embodiment, an aqueous anticorrosive paint for aerosol spraying includes water for dilution (hereinafter also referred to as "dilution water") that is added when it is provided as an aerosol liquid. In such a case, the amount of dilution water may be within a certain ratio to the water-based anticorrosive paint. For example, the amount of water added as dilution water is 0% to 60% by mass, such as 0% to 50% by mass, 0% to 40% by mass, 5% to 40% by mass, 5% by mass, based on the water-based anticorrosive paint. It may be from 5% to 20% by weight, from 5% to 16% by weight, from 7% to 15% by weight, or from 8% to 15% by weight (with dilution water added). Overall standards for applicable water-based anti-corrosion paints). In the aqueous anticorrosive paint diluted in this way, the shell layer in the core-shell emulsion becomes more likely to act as a barrier layer against aerosol propellants such as dimethyl ether and/or corrosion-resistant metal flakes.

Regarding the viscosity suitable for use as an aerosol product, water-based anti-rust paints, for example, have a viscosity of 10 to 60 seconds (room temperature 23 ± 2 °C and It may have a viscosity such that under atmospheric pressure conditions). If the viscosity is lower than this, the atomization properties of the aerosol tend to deteriorate, making it difficult to obtain a more uniform coated surface. Such viscosity/viscosity can be adjusted by adding water for dilution.

Note that the water-based anticorrosive paint according to one embodiment of the present invention may contain water corresponding to the dilution water in advance. This means that the water content in the water-based anticorrosion paint may be increased to some extent. In such cases (i.e., when diluent water is added to the water-based anti-rust paint, or when the water-based anti-corrosion paint already has the desired moisture content without adding it), the water content of the water-based anti-rust paint is , based on its total weight, may be 20% to 90% by weight, 20% to 80% by weight, or 20% to 70% by weight. In some embodiments, the water-based anticorrosive paint suitable for use as the aerosol spray product of the present invention is based on the weight of the entire paint, from 30% to 90% by weight, from 30% to 70% by weight, and from 30% to 60% by weight. % by weight, such as from 40% to 60% by weight, or from 40% to 55% by weight. The "total mass standard" here refers to the total mass of the water-based anti-corrosion paint, including the added dilution water if dilution water has been added or has been added to the water-based anti-corrosion paint. In addition, in the case where the water-based anti-corrosion paint already has the desired moisture content without adding water, the total mass of the water-based anti-corrosion paint without diluting water or the like is used as the standard. In addition, such water-based anticorrosion paint has a viscosity of 10 to 60 seconds (at room temperature 23±2°C and atmospheric pressure conditions) according to Ford Cup #4 (manufactured by Rigosha Co., Ltd., No. 420). It's okay to do so. Water-based anticorrosion paints with such water content and/or viscosity may be used even if mixed with a propellant during aerosolization (especially if mixed with a propellant without the addition of water such as further dilution water). ), the dissolution and gelation of the emulsion particles over time can be easily suppressed, contributing to the desired aerosolization.

In the water-based anticorrosive paint according to an embodiment of the present invention, when the entire paint is 100 parts by weight, the core-shell emulsion (for example, the emulsion as a vehicle) may be 40 to 80 parts by weight, for example 40 to 75 parts by weight. parts, 40 to 70 parts by weight, 40 to 65 parts by weight, or 45 to 65 parts by weight, etc. If the core-shell emulsion is less than 40 parts by mass, the amount of resin required to properly disperse corrosion-resistant metal flakes and any coloring pigment, so-called PVC (Pigment Volume Concentration), will easily exceed the limit value. The pigment tends to become unable to wrap around the pigment particles, and pigment aggregation tends to occur. On the other hand, if the core-shell emulsion exceeds 80 parts by mass, the content of the corrosion-resistant metal flakes will be relatively reduced, and the effect of blocking corrosion factors will be reduced to some degree, and the rust-preventing effect will tend to decrease relatively. Become.

In the water-based anticorrosive paint according to an embodiment of the present invention, when the entire paint is 100 parts by mass, the corrosion-resistant metal flakes may be 5 to 40 parts by mass, for example, 10 to 40 parts by mass, 10 to 35 parts by mass. parts, 10 to 30 parts by weight, or 15 to 30 parts by weight. If the amount of the corrosion-resistant metal flakes is less than 5 parts by mass, even if they are oriented in the coating, the effect of blocking corrosion factors tends to decrease. On the other hand, if the amount of the corrosion-resistant metal flakes exceeds 40 parts by mass, it becomes difficult to achieve suitable orientation, and the effect of blocking corrosion factors tends to decrease.

In one preferred embodiment, the hydrophilic shell layer is a hydrophilic acrylic layer. In other words, the hydrophilic shell layer is a layer containing at least acrylic. This makes it easier to form a more suitable water film barrier layer as an aerosol liquid, and it becomes easier to protect the particle cores from an aerosol propellant such as dimethyl ether. That is, even if the aqueous anticorrosive paint according to the present invention is provided as an aerosol liquid, dissolution and gelation of the emulsion particles can be suitably suppressed, making it easier to achieve the desired aerosolization. For example, in an aqueous acrylic emulsion, a relatively low molecular weight hydrophilic acrylic (hydrophilic acrylic・Polymer) constitutes the shell and the molecular weight is 50,000 or more (for example, 50,000 to 4,000,000, 50,000 to 3,000,000, 50,000 to 2,000,000, 50,000 to 1,500,000, 100,000 to 1,500,000, 300,000 to 1,500,000, 500,000 to 1,500,000 , 750,000 to 1,500,000, or 750,000 The core may be composed of a hydrophobic polymer (for example, a hydrophobic acrylic polymer) having a molecular weight of 1,250,000 yen, and the core and shell may be bonded together by a crosslinking component. In such a case, the shell part as a hydrophilic acrylic layer will more easily protect the core part from an aerosol propellant such as dimethyl ether and/or corrosion-resistant metal flakes, and the water-based anticorrosive paint of the present invention can be more preferably used with dimethyl ether. It is possible to mix them.

In one preferred embodiment, the core-shell emulsion of the water-based anticorrosion paint for aerosol spraying is an acrylic emulsion. That is, the core-shell particles in the core-shell emulsion may correspond to acrylic particles (that is, particles containing acrylic), and preferably, the shell layer of the particles may be a hydrophilic acrylic layer. In such cases, the emulsion particles may be constructed such that a hydrophilic acrylic shell layer surrounds a hydrophobic acrylic core.

The aqueous core-shell emulsion in which the core-shell particles are acrylic particles may be comprised of an acrylic emulsion. The type of acrylic in the acrylic emulsion is not particularly limited, and any acrylic may be used. For example, acrylic may be a homopolymer or a copolymer. For purposes of illustration only, examples of acrylics include ethylene/vinyl acetate/methacrylic acid derivative copolymer emulsion, ethylene/methacrylic acid derivative copolymer emulsion, polymethacrylic acid derivative emulsion, styrene/methacrylic acid derivative copolymer emulsion, etc. can be mentioned. The methacrylic acid derivative may be an acid derivative such as acrylic acid and/or methacrylic acid, or an ester thereof, and may contain at least one or more of these components.

Specific examples of the methacrylic acid derivatives include acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl At least one selected from the group consisting of acrylate, 2-hydroxyethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, and the like can be mentioned. In a preferred embodiment, the core-shell particles (especially core-shell acrylic particles) having a hydrophilic shell layer are particles comprising styrene-acrylic copolymer.

An example of an aqueous emulsion that can form a barrier layer containing water is Polysol AP-6750 (manufactured by Showa Denko). However, compared to core-shell emulsions with a hydrophilic shell layer, they may be less resistant (resistance to aerosol propellants and/or corrosion-resistant metal flakes) and may also be less stable from a time point of view. In other words, it can be said that the acrylic emulsion that can be suitably aerosolized with respect to the anticorrosive paint containing the corrosion-resistant metal foil pieces is a core-shell emulsion having a hydrophilic shell layer.

The shell layer of the core-shell particle is a layer in which an acrylic polymer that is the base coexists with an acrylic polymer that can have ionicity that counters the ionicity that the base polymer can have. It's okay to stay. For example, the base acrylic polymer of the shell base may be anionic, and the shell layer may be comprised of an acrylic polymer moiety or acrylic polymer dispersed in the base acrylic polymer that may be cationic. Good too. Alternatively, the base acrylic polymer serving as the shell base can exhibit cationic properties, and the shell layer is composed of an acrylic polymer portion or an acrylic polymer dispersed in the base acrylic polymer, which can exhibit anionic properties. It's okay. In an aqueous emulsion composed of acrylic core-shell particles having such a shell layer, the particle cores are better protected from aerosol propellants such as dimethyl ether and/or corrosion-resistant metal flakes. In other words, even if the aqueous anticorrosive paint according to the present invention is used as an aerosol liquid, the phenomenon of dissolving and gelling the emulsion particles can be easily suppressed, and as a result, the desired aerosol product can be easily obtained. Become.

The aerosol injection product according to the present invention contains corrosion-resistant metal flakes as a rust-preventing component, but even if it contains such relatively rigid corrosion-resistant metal flakes, it is difficult to form an aerosol product that is stabilized over time. contribute to As mentioned above, even in the presence of a bottled propellant in liquefied or compressed gas form, there is an adverse effect on the emulsion on corrosion-resistant metal flakes, at least due to the presence of a hydrophilic shell layer in the aqueous emulsion. This is because it can be reduced.

The corrosion-resistant metal flakes included in the aqueous anticorrosive paint for aerosol spraying according to the present invention may further contain an inorganic oxide. In particular, it may further contain an inorganic oxide as a rust preventive and/or as a pigment. In particular, by including an inorganic oxide as a rust preventive material, the rust preventive properties of the coating film obtained from the water-based rust preventive paint can become more preferable.

For example, the inorganic oxide is preferably zinc oxide (which may have one or more particulate forms). This is because, in addition to the rust-preventing effect due to the laminated structure of the corrosion-resistant metal flakes, the rust-preventing effect on the base material may be additionally provided due to the sacrificial corrosion protection of zinc oxide. In this case, the water-based rust-preventive paint of the present invention has the feature that it contains a rust-preventive component as an inorganic substance, and in particular, two different inorganic rust-preventive components (inorganic metal flakes and two types of inorganic oxides). ) may have the characteristics of a paint containing.

The type of zinc oxide is not particularly limited. The size and particle diameter of zinc oxide is not particularly limited either, but for example, the average particle diameter of zinc oxide may be 0.1 μm or more and 5 μm or less, such as 0.2 μm or more and 3 μm or less, 0.2 μm or more and 1 μm or less, and 0.2 μm. The thickness may be greater than or equal to 0.8 μm, or greater than or equal to 0.2 μm and less than or equal to 0.5 μm. When using zinc oxide in such a particle size range, even if there is a defect in the formation of the laminated structure of the corrosion-resistant metal flakes, the effect can be reduced or the effect will not be increased, and the rust prevention of the substrate can be achieved through sacrificial corrosion protection. effect can be brought about. In addition, if we place more emphasis on both the performance of the rust prevention effect through sacrificial corrosion prevention and the viewpoint of not unfavorably interfering with the corrosion factor blocking effect of the corrosion-resistant metal flakes, water-based rust prevention paints should be 0.1 to 5 parts by weight, such as 0.1 to 3 parts by weight, 0.1 to 2 parts by weight, 0.1 to 1.5 parts by weight, 0.1 to 1.0 parts by weight, 0.5 to 1 part by weight .5 parts by weight, or 0.7 to 1.3 parts by weight of zinc oxide.

The inorganic oxide is not limited to zinc oxide, and may include oxides of other metals. More specifically, the inorganic oxide may be an oxide containing at least one metal component selected from the group consisting of zinc, titanium, aluminum, iron, copper, and zirconium.

In addition, in the aqueous anticorrosive paint for aerosol injection according to the present invention, an inorganic or organic pigment such as titanium oxide or carbon black may be added as necessary. In such a case, after the addition of such an inorganic or organic pigment, the pigment may be formed into a paint by carrying out usual stirring and dispersion or kneading and dispersion.

Furthermore, the aqueous rust-inhibiting paint for aerosol spraying according to the present invention may contain additives or the like commonly used in water-based paints, such as emulsifiers, dispersants, thickeners, extinguishers, etc. At least one selected from the group consisting of foaming agents, surface conditioning agents, anti-settling agents, etc. may be appropriately blended. For example, with respect to the dispersant, it may be one that helps at least disperse the corrosion-resistant metal flakes in the paint. The type of such dispersant is not particularly limited. For example, commercially available aqueous dispersants that have the function of dispersing pigments, such as BYK-151, 153, 154, 155 and 156, DISPERBYK series (BYK-Chemie), DISPERON series (represented by DISPERON AQ-320) Kusumoto Kasei Co., Ltd.), Nopcosperse series represented by Nopcosperse K, Nopcosperse R, and Nopcosperse 44-C (manufactured by San Nopcos Co., Ltd.) are examples of dispersants. (Cationic, anionic and/or nonionic surfactants can be used alone or in combination.)

By way of example only, water-based anticorrosive paints may contain such additives in addition to a water-based core-shell emulsion, corrosion-resistant metal flakes (e.g., stainless steel foil), zinc oxide, pigments (e.g., titanium oxide), and water. (By way of example only, the "other" additives in Table 1 are antifoaming agents and thickening agents). In the present invention, there are no particular restrictions on the brand and/or type of additive.

Since the anticorrosive paint of the present invention is strictly "aqueous", it does not use an organic solvent as a medium. Therefore, the anticorrosive paint of the present invention preferably does not contain an organic solvent that volatilizes and evaporates after application. Regarding this, the anti-rust paint of the present invention requires the installation of exhaust equipment and/or the use of protective gear such as a gas mask for organic gas and an air supply mask according to the Specified Chemical Substance Hazard Prevention Regulations and/or the Organic Solvent Poisoning Prevention Regulations. Contains no organic solvents or organic components that would otherwise be contaminated. For example, the anticorrosive paint of the present invention does not contain aromatic hydrocarbons, and more preferably does not contain harmful aromatic hydrocarbons such as ethylbenzene, xylene and/or toluene.

[Aerosol product of the present invention]
The present invention also provides an aerosol product comprising the above-described water-based anticorrosive paint. Specifically, an aerosol product is provided in which a container is filled with the above-mentioned water-based anticorrosive paint for aerosol injection and a propellant for aerosolization.

In the present specification, the term "aerosol product" broadly refers to a product that can release the contents inside the container to the outside of the container by the action of a propellant. In a narrow sense, an "aerosol product" is a product or structure that can release the contents of the container outside the container in the form of a mist and/or foam by using the pressure of a propellant placed inside the container. pointing.

In the aerosol product according to the present invention, in the container, the aqueous anticorrosion paint used for the aerosol filling paint stock solution contains a core-shell emulsion (particularly a core-shell emulsion containing a hydrophilic shell layer), and the above-mentioned anticorrosive paint is used as a rust preventive material. Contains corrosion-resistant metal flakes. As described above, the aerosol product of the present invention has desired aerosol properties even though the rust-preventive paint containing corrosion-resistant metal flakes as a rust-preventive material is used together with a propellant such as a hydrocarbon material.

As an aerosol product, the propellant may correspond to a propellant gas charged into the container or, in some cases, a propellant. The type of propellant gas is not particularly limited as long as it is used in general aerosol products. In other words, the propellant charged in the container may correspond to a liquefied gas and/or a compressed gas. In terms of the inclusion of such a propellant, the aerosol product according to the present invention corresponds to a gas pressure spray product and is essentially different from a hand spray type such as a so-called "mist spray".

The propellant in the aerosol article of the invention may be a propellant comprising a hydrocarbon. Such hydrocarbons are not particularly limited as long as they are commonly used as aerosol paint stock solutions. For example, in an aerosol product, the hydrocarbon used with the water-based anticorrosive paint may be at least one selected from the group consisting of liquefied petroleum gas, linear ethers, and fluorinated hydrocarbons. An example of the straight chain ether is dimethyl ether. From another perspective, the hydrocarbon of the propellant may contain, for example, an alkyl group having 1 to 10 carbon atoms, such as 1 to 8, 1 to 7, 1 to 6, 1 It may contain up to 5, 1-4, 1-3, or 1-2 alkyl groups. More specific examples of such alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n- Examples include pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, and/or n-decyl group. Similarly, from another perspective, the propellant hydrocarbons may contain halogen atoms in their molecular structure, such as fluorine (F), chlorine (Cl), bromine (Br) and/or iodine (I). ) may also be included.

The container used for the aerosol product may be any container as long as it can maintain a state filled with both the water-based anticorrosive paint and the propellant for aerosol spraying. For example, the container used for the aerosol product may be a closed container. Additionally, the container used for the aerosol product may be a rigid and/or pressure-resistant container, for example a metal container. Containers for such aerosolization may be equipped with dip tubes, valves, actuators, buttons, nozzles, and/or caps, and the like. That is, there are no particular restrictions on the elements other than the contents of the aerosol product according to the present invention. Therefore, containers that are the same or similar to those commonly used for aerosol products can be used, and their accessories and related components (e.g. dip tubes, valves, actuators, buttons, nozzles and/or caps, etc.) may also be the same or similar to those commonly used as aerosol products.

By way of example only, the container may be a can used for industrial products such as insecticides, cosmetics, and grease. The inner surface of the can may be coated with a resin and/or laminated to better encapsulate the water-based anticorrosive paint. Furthermore, if portability is particularly important, the container capacity may be around 100 to 500 mL or 200 to 400 mL, for example. Furthermore, spheres (particularly rigid spheres) may be placed in the container to help mix the contents. For example, by putting one or more glass beads (for example, 1 to 5, preferably 1 to 2) with a diameter of about 8 mm to about 15 mm and sealing the can, the contents can be mixed by shaking the can when spraying. to make it easier to make it uniform. There are no particular restrictions on the diameter or shape of the nozzle, and they may be used as appropriate depending on the purpose.

The aerosol product of the present invention is obtained by combining an aqueous anticorrosive paint as an aerosol-filled paint stock solution with a propellant in a closed container. For example, an aqueous anticorrosive paint diluted with water as necessary is combined with a propellant (eg, the above-mentioned hydrocarbon) in a closed container as an aerosol-filled paint stock solution to provide an aerosol product. For example, to obtain an aerosol product, to 100 parts by weight of such an aerosol-filled paint stock solution, 10 to 70 parts by weight of a propellant (such as a hydrocarbon as mentioned above) may be combined, for example 10 to 60 parts by weight, 10 to 50 parts by weight, 20 to 50 parts by weight, or 30 to 50 parts by weight of a propellant (eg, a hydrocarbon as described above) may be combined. The term "aerosol filled paint stock solution" as used herein refers to a paint stock solution that is combined with a propellant to obtain an aerosol product. It can be taken to mean a water-based rust-preventive paint that already has the desired water content.

In the aerosol product of the present invention, since the water-based anti-rust paint used in the aerosol-filled paint stock solution contains corrosion-resistant metal flakes, a coating film exhibiting more suitable anti-rust properties can be formed. This results in an aerosol product in which the particle core portion of the emulsion is better protected from the aerosol propellant. That is, even though the aerosol product of the present invention contains corrosion-resistant metal flakes, an emulsion state is obtained in which the product is more suitably mixed with the aerosol propellant, contributing to the desired aerosolization.

In the aerosol product of the present invention, the above-mentioned water-based anticorrosive paint may be diluted with dilution water and filled in a container. That is, the water-based anticorrosion paint may be diluted with water in order to further enhance the resistance (so-called storage stability, etc.) of the paint within the aerosol product. In addition, if the aqueous anticorrosive paint already has a desired moisture content without dilution, water may not be added during aerosolization. In any case, when considered as the contents of a container of an aerosol product, the water content may be 20% to 50% by mass, for example, 25% by mass based on the total mass of the contents of the container of the aerosol product. Mass % to 50 mass %, 25 mass % to 47 mass %, 26 mass % to 40 mass %, 26 mass % to 35 mass %, 27 mass % to 35 mass %, 28 mass % to 35 mass % or 29 mass % It is preferable that the amount is 35% by mass. Such a water content can improve the effect of stabilizing the emulsion over time in an aerosol spray paint. In other words, even though the aerosol spray paint is prepared from a water-based anticorrosion paint, it can be an aerosol product that is stable over time.

The term "container contents of an aerosol product" as used herein refers to the contents contained in the container of an aerosol product, and to put it simply, it refers to the "paint mixture" in the container ( (Excluding "rigid spheres" that may be incorporated to promote mixing or agitation, etc.) Typically, "container contents of an aerosol product" refers to a mixture consisting of the "aqueous anticorrosive paint" described above, optional diluent water, and a propellant.

The above-mentioned water-based anti-rust paint may have a viscosity of 10 to 60 seconds according to Ford Cup #4 (manufactured by Rigosha Co., Ltd., No. 420), which is a solution viscosity suitable for aerosol, and has good applicability to steel materials. More importantly, it may take 20 to 40 seconds (at room temperature of 23±2° C. and atmospheric pressure conditions). The paint, which has been diluted with water as necessary to achieve the desired viscosity, may be used as an aerosol-filled paint stock solution, and a propellant containing a hydrocarbon may be added thereto to form an aerosol sprayed product. Note that the water used for dilution may be tap water, purified water, deionized water, distilled water, and/or ion-exchanged water.

In the aerosol product of the present invention, the content of the resin component (simply put, the emulsion resin component or emulsion polymer component, particularly the resin component of the core-shell emulsion in the aerosol product) is based on the total mass of the container contents.・Polymer component) may be 5% to 50% by mass, for example, 5% to 40% by mass, 5% to 30% by mass, 5% to 20% by mass, 5% to 15% by mass. , 7% to 15% by weight, or 8% to 15% by weight, etc. As a result, even though the aerosol spray paint is prepared from a water-based anticorrosive paint, it tends to be an aerosol product that is stable over time.

In the aerosol product of the present invention, the amount of corrosion-resistant metal flakes may be 5% to 35% by mass, for example 5% to 30% by mass, 5% to 25% by mass, based on the total mass of the container contents. , 5% by mass to 20% by mass, or 10% to 20% by mass. As a result, even though the aerosol spray paint is prepared from a water-based anticorrosive paint, it tends to be an aerosol product that is stable over time.

In the aerosol product of the present invention, the propellant content may be 10% to 40% by mass, for example 20% to 40% by mass, 20% to 30% by mass, based on the total mass of the container contents. Alternatively, it is preferably 25% by mass to 30% by mass. As a result, even though the aerosol spray paint is prepared from a water-based anticorrosive paint, it tends to be an aerosol product that is stable over time.

In the aerosol product of the present invention, zinc oxide may be present in an amount of 0.2% by mass to 1.0% by mass, for example, 0.2% by mass to 0.8% by mass, based on the total mass of the contents of the container. The content is preferably 0.3% by mass to 0.7% by mass, 0.4% by mass to 0.7% by mass, or 0.5% by mass to 0.7% by mass. As a result, even though the aerosol spray paint is prepared from a water-based anticorrosive paint, it tends to be an aerosol product that is stable over time.

In one preferred embodiment, the aerosol product of the present invention comprises a resin component (resin component of the core-shell emulsion), corrosion-resistant metal flakes, water, and a propellant, based on the total weight of the container contents of the aerosol product. The content of the resin component (polymer component) is 5% by mass to 15% by mass, the content of the corrosion-resistant metal flakes is 10% by mass to 20% by mass, the content of water is 27% by mass to 35% by mass, and the propellant. The content of the resin component is 20% to 30% by mass, or the content of the resin component (polymer component) is 5% to 12% by mass, and the content of the corrosion-resistant metal flake is 10% to 19% by mass. , the content of water is 27% to 35% by mass (for example, 28% to 35% by mass or 29% to 35% by mass, etc.), the content of propellant is 20% to 29% by mass, etc. or In the case of such a content, the aerosol product is likely to be stable over time even though it is an aerosol spray paint prepared from an aqueous anticorrosive paint.

For example, the aerosol product of the present invention exists stably for at least several months, and even after several months, it can be suitably used as an aerosol product for a desired water-based anticorrosive paint (particularly, the "aerosol properties"/ It can be used favorably at least in terms of "aerosol workability"). For example, it can be suitably used as an aerosol product even after at least 1 month, 2 months, 3 months, 4 months, 5 months, 6 months, 7 months, 8 months, or 9 months after manufacture, and in some cases, Even if a longer period of time has elapsed (for example, 10 months, 12 months, or about a year after manufacture), it can be suitably used as an aerosol product.

There are no particular restrictions on how the aerosol product is used. For example, there are no particular limitations on the distance between the aerosol product and the target substrate during spraying. As just one example, the distance between the target substrate and the aerosol product (more specifically, its paint discharge port) may be about 20 to 40 cm.

The present invention also provides a method of manufacturing an aerosol product. The manufacturing method of the present invention comprises combining the above-mentioned water-based anticorrosive paint and a propellant to obtain the contents of a container for an aerosol product. In the production method of the present invention, the aqueous anticorrosive paint combined with a propellant includes a water-based emulsion and corrosion-resistant metal flakes, the aqueous emulsion is a core-shell emulsion, and the core-shell particles in the core-shell emulsion are hydrophilic. It is characterized by having a sexual shell.

The propellant may be a propellant comprising a hydrocarbon, as described above, where such hydrocarbon is at least one selected from the group consisting of liquefied petroleum gas, linear ethers and fluorinated hydrocarbons. It's good. The linear ether may be, for example, dimethyl ether (DME), and as such DME as a propellant, a commercially available product can be used without any particular restriction (for example, a commercially available DME product may be used without special adjustment). ). The method of obtaining an aerosol product by combining such a propellant and a water-based anti-rust paint is not particularly limited, and is commonly used by aerosol manufacturers to obtain an aerosol product from an aerosol coating raw material and a propellant. The method may be the same or similar.

In the manufacturing method of the present invention, the water-based anticorrosive paint may be diluted with water, if necessary, before being combined with the propellant. For example, the viscosity of Ford Cup #4 (manufactured by Rigosha Co., Ltd., No. 420) is diluted with water so that the viscosity is 10 to 60 seconds, for example, 20 to 40 seconds (at room temperature 23 ± 2 °C and atmospheric pressure conditions). It's fine.

Further details regarding the "water-based anti-rust paint" used in the aerosol product of the present invention (or "water-based anti-rust paint" used in the manufacturing method of the aerosol product of the present invention), further specific aspects, etc. Since the matters have been explained in the above-mentioned [Water-based rust-preventing paint of the present invention], the explanation here will be omitted to avoid duplication.

In addition, the components and contents of the container contents of the aqueous anticorrosive paint and aerosol product according to the present invention can be understood in principle from the preparation of the composition (raw materials used), and in particular from the raw material preparation ratio. can. In addition, by subjecting the paint and container contents to instrumental analysis, qualitative and/or quantitative analysis of the raw material components can be performed, and thereby the content (presence) of the components and/or their content can also be ascertained. Specifically, "separation analysis" such as chromatography, electrophoresis and/or gel filtration, absorption analysis and/or emission analysis, such as visible absorption analysis, ultraviolet absorption analysis, infrared absorption analysis, atomic absorption analysis , "optical analysis" such as Raman spectroscopy, emission spectroscopy, and/or fluorescence analysis; "electromagnetic analysis" such as nuclear magnetic resonance analysis and/or electron spin resonance analysis; potentiometric, ion electrode, and/or polar Qualitative and/or quantitative analysis can be performed on the components of paint and aerosol product container contents by using electrochemical analysis such as chromography or other analytical methods such as thermal analysis. . The analytical equipment used is not a special one, but can be one that is known to those skilled in the coatings industry, thereby allowing qualitative analysis and analysis of the raw material components of the target coating or aerosol container contents. /or Quantitative analysis can be performed.

Although the embodiments of the present invention have been described above, they are merely typical examples within the scope of the present invention. Therefore, those skilled in the art will easily understand that the present invention is not limited to the embodiments described above, and that various changes can be made.

For example, in the above description, a mode in which water for dilution is added when a water-based anticorrosive paint is used as an aerosol product has been mentioned, but the present invention does not necessarily require water for dilution. If the water-based anticorrosive paint already has a desired water content or a desired viscosity/viscosity, such "water for dilution" may not be used. That is, an embodiment may be adopted in which the aqueous anticorrosive paint is combined with the propellant without being diluted with water during aerosolization.

Tests were conducted in connection with the present invention. Specifically, in view of actual use, a demonstration test was conducted to confirm the suitable aerosolization of water-based anticorrosion paint. Note that the Examples and Comparative Examples listed below are merely illustrative and do not limit the scope of the present invention. In the examples, "%" is based on mass unless otherwise specified.

As Example 1, a water-based antirust paint was prepared. Specifically, the following paint components were stirred with a disper so that the proportions shown in Table 1 were obtained to prepare a water-based anticorrosive paint.

Example 1
<Aqueous emulsion>
In Example 1, a core-shell emulsion was used as the aqueous emulsion, particularly a core-shell emulsion in which the core-shell particles had a hydrophilic shell layer. Specifically, Akrit AKW-107 manufactured by Taisei Fine Chemical Co., Ltd. was used as the vehicle. The physical properties of this aqueous core-shell emulsion are as follows.

・Aqueous core-shell emulsion Composition: Styrene-acrylic copolymer emulsion Tg: 20℃ (core part), 30℃ (shell part)
MFT: 5℃
Solid content (solid content of emulsion as vehicle): 30.0% ± 1.5%
Viscosity: 50±40 mPa・s
pH: 8.0±1.0
Weight average molecular weight: Approximately 1 million (core part), approximately 20,000 (shell part)

<Corrosion-resistant metal flakes>
The following styrene steel foil was used as the corrosion-resistant metal flake.

- Scaly stainless steel foil (manufactured by Toyo Aluminum Co., Ltd., RFA4500)
Material: SUS316L
50% particle size: 28μm
Thickness: 0.3μm
Aspect ratio: average 2.1 (long side/short side)

The following were used as other components of the paint. That is, the subcomponents are as follows.

・Zinc oxide (pigment)
JIS standard type 2 equivalent product (manufactured by Hakusui Tech Co., Ltd.)
Average particle size: 0.3μm

・Titanium oxide (coloring pigment)
Titanium dioxide (manufactured by Teika Co., Ltd., TITANIX JR-600A)
Density: 4.1g/ ^cm3 (20℃)
Average particle size: 0.2μm

・Dispersant Aqueous dispersant (manufactured by BYK-Chemie, DISPERBYK-2015)

The obtained water-based anti-rust paint was diluted with water, and the viscosity was adjusted to 10 to 60 seconds (at room temperature of 23±2°C and atmospheric pressure) using Ford Cup #4 (manufactured by Rigosha Co., Ltd., No. 420). Adjusted to. The water-based anticorrosive paint was then mixed with an aerosol propellant. Specifically, the following hydrocarbon propellant was sealed in an aerosol injection container filled with water-based anti-corrosion paint at the mixing ratio shown in Table 1, and a propellant-mixed paint was produced as an aerosol injection product. did.

・Hydrocarbon propellant dimethyl ether (C ₂ H ₆ O)
Boiling point: -23.6℃,
Solubility in water: 7.1g/100g (20℃)

Examples 2-4
Propellant mixed paints were produced in the same manner as in Example 1 above, except that the blending ratios of paint components and diluent water were changed as shown in Table 1.

Comparative example 1
The above procedure was carried out except that "an emulsion that is a core-shell emulsion but whose shell layer of core-shell particles is not hydrophilic (Acrit UW-550CS: solid content 35%/manufactured by Taisei Fine Chemical Co., Ltd.)" was used as the aqueous emulsion. A propellant-mixed paint was produced in the same manner as in Example 1 (the blending ratios of paint components are shown in Table 1).

Comparative example 2
The above except that "an emulsion which is not a core-shell emulsion and which forms a hydrophilic layer around the emulsion particles (Polysol AP-6750: solid content 45%/manufactured by Showa Denko K.K.)" was used as the aqueous emulsion. A propellant-mixed paint was produced in the same manner as in Example 1 (the blending ratios of paint components are shown in Table 1).

Comparative example 3
Other than using "a general-purpose acrylic emulsion (Polysol AP-691T: solid content 55%/manufactured by Showa Denko K.K.), which is not a core-shell emulsion and does not form a hydrophilic layer around the emulsion particles" as the aqueous emulsion. produced a propellant-mixed paint in the same manner as in Example 1 above (the blending ratios of paint components are shown in Table 1).

Comparative example 4
A propellant-mixed paint was produced in the same manner as in Example 1 above, except that the corrosion-resistant metal flakes were not used (the blending ratios of paint components are shown in Table 1).

table 1

The propellant mixed paints of Examples 1 to 4 and Comparative Examples 1 to 4 were used to evaluate the following properties: "aerosolization after production," "rust prevention," "weather resistance," and "aerosol retention (aerosol after long-term storage)." Characteristics)" were evaluated respectively.

In the evaluation, a steel plate (JIS G3141, cold rolled steel plate) with a size of 70 mm x 150 mm x 0.8 mm was polished with abrasive paper and degreased with ethyl acetate and used as a test piece. Two such test pieces were prepared for each paint and tested at the same time.

The propellant mixed paint was shaken 30 times with the sealed container, and the paint in the container was stirred with a glass ball in the container, so that the dry coating film on the test piece was 50 to 80 μm at room temperature (23 ± 2 ° C.). Spray painting was carried out under atmospheric pressure (the distance between the paint outlet in the container and the test piece was 30 cm). Note that a container with the following specifications was used.

・Container: 60φ×210 D30R M1-13 cutting NET330mL (manufactured by Machiyama Seisakusho Co., Ltd.)
・Valve: A80W24 (U) 76163 (0.6) x 180 UC G-207 (manufactured by Maruichi Co., Ltd.)
・One-touch cap: White-215-3 (1.0)/C-151 (manufactured by Maruichi Co., Ltd.)
・Rigid balls for stirring: Glass beads (diameter 12mm/2 pieces)

<Post-manufacturing aerosol test>

We attempted spray painting to confirm aerosol workability immediately after manufacture. Specifically, the mist state and the state of the coated surface when spray painting the propellant-mixed paint for a short period of time (within 7 days) after manufacture were evaluated using the following evaluation criteria.

◎: The fog is very fine (maximum fog droplet ^*1 : less than 1.0 μm) and is uniformly applied (does not include areas with surface roughness Rz ^*2 of 5 μm or more)
〇: Good atomization (fog droplets: 1.0 μm or more, including less than 10.0 μm), and a normal painted surface can be obtained (Rz less than 10 μm, including areas with surface roughness Rz of 5 μm or more)
△: Atomization is slightly poor (fog droplets: 10.0 μm or more and less than 50.0 μm), and the coated surface is uneven (including areas with surface roughness Rz of 10 μm or more).
×: Poor atomization (including the maximum mist droplet of 100 μm or more), the coated surface is not uniform (including the surface roughness Rz of 10 μm or more), or no coating film is formed.


*1: Mist droplets are determined by the peripheral area of the spray body in an image taken of the spray body between the paint outlet of the container and the test piece during spraying. In particular, from the outermost edge of the spray body to the "width dimension (in particular, the width direction dimension corresponding to the direction perpendicular to the spray direction, from a point 15 cm apart in the spray direction from the paint discharge port of the container in the spray direction)" Judgment is made based on the local peripheral area (1 cm x 1 cm square size local peripheral area in the image) up to the inside by 1/10 of the length (width dimension in the direction perpendicular to the width direction). Note that the "spraying direction" corresponds to the direction normal (perpendicular) to the opening surface of the paint discharge port for spraying.

*2: "Rz" related to surface roughness is the 5th peak from the highest peak, which is measured by extracting only the standard length from the roughness curve in the direction of its average line, and measuring from the average line of this sampled part in the direction of vertical magnification. Calculate the sum of the average absolute value of the mountain top elevation (Yp) up to the peak and the average absolute value of the absolute value of the valley bottom elevation (Yv) from the lowest to the fifth valley floor, and calculate this value in micrometers (μm). (Refer to JIS B0601:1994) Judging from the image of the side of the paint film.

<Rust prevention>
A test was conducted in accordance with "JISK-5600-7-1 Long-term durability of coating film - neutral diving spray resistance", and evaluation was made using the following evaluation criteria. The test pieces were exposed to salt water spray at 35° C. for 60 days, and then the degree of rust, blistering, and peeling that could occur on the scratched portions and painted surfaces of the test pieces was determined. After the immersion period, the test pieces were taken out and dried in a room at 23° C. for 1 hour before being evaluated.

◎: No defects such as blistering or peeling are observed on the painted surface, and no rust is generated from the scratched area. ○: Rust has spread within 1 cm at the scratched area, but no defects are observed on the painted surface × : Defects have occurred in the paint film such as blistering and/or peeling, and rust has formed on the base steel plate.

<Weather resistance>
A test was conducted according to "JISK-5600-7-7 Accelerated weather resistance and accelerated light resistance (xenon lamp method)" and evaluation was made using the following evaluation criteria. The accelerated weathering tester used was a 7.5kW Xenon NX75 (manufactured by Suga Test Instruments Co., Ltd.). In addition, as a panel subjected to such weather resistance, a panel whose back surface and edges were subjected to masking treatment was used.

◎: No defects such as blistering, peeling, gloss and discoloration are observed on the painted surface. ○: Gloss and/or discoloration has occurred, but no coating defects such as blistering, cracking and peeling have occurred. No ×: Defects such as blistering and/or peeling have occurred in the coating film, and rust has formed on the base steel plate.

<Aerosol characteristics after long-term storage>
Aerosol retention was evaluated. In particular, the aerosol properties after long-term storage were evaluated. Such aerosol retention/storability is an important indicator when using a water-based anticorrosive paint as an aerosol paint from a practical standpoint.
Specifically, the aerosol paint was sealed in an aerosol injection container, stored at 45°C, and after 3 months had passed, the paint was cooled to room temperature (23±2°C), and the aerosol workability was evaluated. The evaluation was performed in the same manner as in the above "post-manufacturing aerosol test".

"comprehensive evaluation"
The above tests and evaluations were comprehensively evaluated, and the paints of Examples 1 to 4 and Comparative Examples 1 to 4 were evaluated.

◎: There is no × in the above evaluation items and one or more ◎. 〇: There is no × in the above evaluation items and less than one ◎ (all are 〇).
×: One or more × in the above evaluation items

As a comprehensive evaluation, "◎" indicates that the product can be used in a more preferable manner as an aerosol product, especially from the viewpoint of actual use.

As an overall evaluation, "〇" indicates that the product can be used as an aerosol product from the viewpoint of actual use.

An overall evaluation of "x" means that there are problems from the viewpoint of actual use, and the product cannot be used as an aerosol product from a practical viewpoint.

The results are shown in Table 2 below.

Table 2

As can be seen from Table 2, an aerosol product prepared from a water-based anticorrosive paint containing a core-shell emulsion as an aqueous emulsion, in which the core-shell particles in the core-shell emulsion have a hydrophilic shell layer, has anti-rust properties due to corrosion-resistant metal flakes. It was found that this aerosol product is suitable from the viewpoint of actual use, although it provides certain characteristics.

Since the paint of the present invention is a rust-preventing paint, it can be used on substrates that require rust prevention. In particular, since it is a water-based rust-preventive paint that does not contain harmful organic solvents, it can be suitably used for repairing steel materials, etc., mainly in closed spaces, in view of worker safety. Steel materials that are subject to such rust prevention include, but are not particularly limited to, steel structures such as bridges and steel towers located on the sea or at high places, steel materials for ships, railway vehicles, containers, vehicle loading platforms, etc. can be mentioned.
In addition, although the water-based anti-rust paint of the present invention is water-based and contains a metal rust preventive agent as a rust-preventive component, it can be suitably converted into an aerosol, thereby improving worker safety and work efficiency. In view of both of the above, the paint is particularly suitable for use in the above-mentioned "mainly closed spaces".

Note that the aerosol atomization related to the present invention is essentially different from a simple spray atomization, and can be industrially useful in that respect as well. In other words, simple spraying is performed manually, and is inferior to aerosol spraying in terms of application efficiency. This is because aerosol spraying uses a propellant that is filled in a container with the paint in the form of liquefied gas or compressed gas, and the pressure of the propellant can be used to efficiently and forcefully spray the paint. . Moreover, manual spraying tends to cause nozzle clogging, making spraying impossible or reducing spray efficiency, whereas aerosol spraying using a propellant is less likely to cause this.

Finally, I would like to add an additional comment regarding the disclosures of "Japanese Patent Application Publication No. 2016-510082" (Patent Document 2) and "Japanese Patent Application Publication No. 2003-82294" (Patent Document 3).
First, although JP-A No. 2016-510082 and JP-A No. 2003-82294 mention aerosolization, they do not relate to water-based anti-rust paints exhibiting desired anti-rust properties. It is speculated that this may be due to the difficulty in aerosolizing water-based anticorrosive paints that exhibit the desired antirust properties, as explained in [Findings forming the basis of the present invention]. .
For example, there are paints on the market that use water-soluble resins such as water-soluble acrylic resins and water-soluble urethane resins that are not core-shell type. Since many of these paints on the market are water-soluble in the first place, they cannot be said to have desirable weather resistance or water resistance after coating film formation. Therefore, it is mainly used for parts such as indoor walls and furniture that are not wet and is used in a low-humidity environment, and there are actually few examples of its use in an external environment exposed to wind and rain. In this respect, the water-based anticorrosive paint according to the present invention can be used more suitably even in such an external environment.
The aerosolization of an aqueous emulsion disclosed in "Japanese Unexamined Patent Publication No. 2016-510082" (Patent Document 2) is not intended for rust prevention purposes, but specifically for the inorganic rust preventive agent or metal rust preventive agent developed by the inventors. "Corrosion-resistant metal flakes" (for example, scaly stainless steel foil) corresponding to the agent are not blended. When agitated and dispersed during paint formulation, there is a concern that corrosion-resistant metal flakes may break the structure of emulsion particles, even particles with a two-layer structure such as a core-shell emulsion. This is because the corrosion-resistant metal flakes are strong in themselves, so they do not easily lose their shape even if shear is applied during stirring and dispersion of the paint. In other words, even when agitation shear is applied, there is usually a concern that the emulsion particles will continue to have an adverse effect on the emulsion particles together with other pigments without losing their shape. Even if there are few problems during paint production, the emulsion particles can be affected over time under pressure. Particularly when the product is sealed together with a propellant gas as an aerosol product, the influence on the emulsion particles may increase due to agglomeration of corrosion-resistant metal flakes over time. Additionally, an aerosol can may be strongly shaken many times just before spraying the aerosol, and there is usually concern that each shake may have an adverse effect on the emulsion particles for the same reason. Regarding this, in the present invention, such adverse effects are reduced at least due to the fact that "the core-shell particles in the core-shell emulsion have a hydrophilic shell layer", and the aerosol product becomes more stable over time. can be provided.

Claims (14)

A water-based anti-rust paint for aerosol,
comprising an aqueous emulsion and a corrosion-resistant metal flake,
An aqueous anticorrosive paint for aerosol, comprising a core-shell emulsion as the aqueous emulsion, wherein core-shell particles in the core-shell emulsion have a hydrophilic shell layer. 2. The aqueous anticorrosive paint for aerosol according to claim 1, wherein in the core-shell particles, the hydrophilic shell layer is a hydrophilic polymer shell and the particle core is a hydrophobic polymer core. The aqueous anticorrosive paint for aerosol according to claim 1 or 2, wherein the hydrophilic shell layer retains moisture and forms a water film. The aqueous anticorrosive paint for aerosol according to any one of claims 1 to 3, wherein the core-shell emulsion is an acrylic emulsion. The aqueous anticorrosive paint for aerosol according to any one of claims 1 to 4, wherein the corrosion-resistant metal flake is a scale-like stainless steel foil. The aqueous anticorrosive paint for aerosol according to any one of claims 1 to 5, further comprising an inorganic oxide. The aqueous anticorrosive paint for aerosol according to claim 6, wherein the inorganic oxide is zinc oxide. An aerosol product comprising a container filled with the water-based anticorrosive paint according to any one of claims 1 to 7 and a propellant for aerosolization. 9. The aerosol article of claim 8, wherein the propellant is a propellant comprising a hydrocarbon. The aerosol product according to claim 8 or 9, wherein the propellant is a propellant comprising dimethyl ether. The aerosol product according to any one of claims 8 to 10, having a water content of 25% to 50% by weight based on the total weight of the container contents of the aerosol product. The aerosol product according to any one of claims 8 to 11, having a content of the emulsion resin component of 5% by mass to 15% by mass based on the total mass of the container contents of the aerosol product. The aerosol product according to any one of claims 8 to 12, having a content of the corrosion-resistant metal flakes of 5% to 20% by mass based on the total mass of the container contents of the aerosol product. Aerosol product according to any one of claims 8 to 13, having a content of the propellant of 20% to 30% by weight based on the total weight of the container contents of the aerosol product.