JP6761950B2 - A method for manufacturing a rust preventive film, a rust preventive member having a rust preventive film, and a rust preventive member. - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention provides a colored rust-preventive coating and a rust-preventive member having high corrosion resistance and white rust resistance even if the thin film is applicable to a steel sheet for press molding of precision equipment and automobiles, for example. And a method for manufacturing a rust preventive member.

In the field of paints for the purpose of preventing rust on steel, rust preventive paints containing zinc powder and chromic acid as main components have been widely used. This rust preventive paint can keep the zinc powder stable for a long period of time due to the passivation action of hexavalent chromium, and is excellent in the storage stability of the liquid. Further, the film made of the rust preventive paint containing the zinc-based powder effectively works the sacrificial anticorrosive action by the well-known zinc to prevent the corrosion of the underlying steel, so that an excellent rust preventive effect can be obtained.

However, in recent years, there have been concerns about environmental pollution and health hazards to the human body due to the harmful effects of hexavalent chromium, and the movement to legally regulate the use of harmful metals such as hexavalent chromium is accelerating. In response to this trend, companies that manufacture consumer products such as precision equipment and automobiles are considering not using harmful metals such as hexavalent chromium at all. Therefore, in the field of rust preventive paints, rust preventive paints that do not contain any harmful metals such as chromium are strongly desired.

An example of such a rust-preventive paint containing no chromium is a type of rust-preventive paint in which a zinc-based powder and a binder component are dispersed or dissolved in an organic solvent, that is, zinc rich paint. There are two types of this zinc rich paint, organic and inorganic. From the viewpoint of durability, the inorganic type using an organosilicon compound as a vehicle is superior. For example, it is used as an undercoat in heavy-duty anticorrosion coating of ships and bridges. Has been done.

However, the inorganic zinc rich paint tends to generate voids in the film, and it is difficult to control the thickness of the film. In order to overcome such a drawback, the following techniques are disclosed.

Patent Document 1 discloses a technique for additionally containing whiskers-like calcium carbonate having a major axis of 20 to 30 μm. In this technique, the added whiskers have a function of preventing cracks in the coating.

Further, Patent Document 2 discloses a zinc rich paint in which an alkyl silicate resin having a weight average molecular weight / number average molecular weight ratio of 40 or less is used and the morpholin gel time of the paint is 60 seconds or less. It is explained that such paints have a fast curing time, which suppresses the phenomenon that cracks develop and connect with voids.

Although such a technique is certainly effective as a thick-film zinc rich paint, it is possible to provide a paint capable of stably forming a thin film of about 10 μm and having a highly anticorrosive coating film. Not.

The main uses of such thin films with high corrosion resistance are office equipment, electrical equipment, automobiles, etc. Specifically, fastening parts such as bolts and nuts, fasteners such as clamps and clips, plates, etc. Examples thereof include press-molded products such as housings, hinges, and panels. Although these members have strict assembly accuracy, they often receive a strong shearing force during processing or assembly, and a high level of strength and adhesion of the coating itself is required.

One effective means of meeting such demand is high temperature baking of the coating. However, when the zinc rich paint according to the conventional technique is baked at a high temperature of about 300 ° C., the organosilicon compound serving as a binder shrinks rapidly, and even if the technique according to the patent document as described above is used, cracks in the coating film are formed. The progress cannot be stopped, and even breakage may occur in the steel material of the substrate.

Therefore, it is an important technical issue to provide a rust preventive coating material capable of forming a thin film in which cracks are unlikely to occur even if a baking treatment is performed at a high temperature without using any harmful metal compound such as chromium. In this regard, the applicant has proposed a rust preventive coating material containing a non-aqueous binder and a metal powder, and using a solution containing an organosilicon compound and an organotitanate compound as the non-aqueous binder (Patent Document). See 3.). This rust preventive paint not only has high corrosion resistance, but also has an advantageous effect of having a long pot life. By using the above-mentioned rust preventive paint proposed by the applicant, a high degree of corrosion resistance can be imparted.

In order to color the member, it is necessary to add a coloring component to the rust preventive paint or to apply the colored paint to the surface of the rust preventive paint. However, when a coloring component is added to the rust preventive paint, the color tone becomes muddy, so that there is a problem that the appearance of the member cannot be colored in a vivid color . If applying a pigmented coating to the surface of the anticorrosive paint, can be colored in bright colors, colored paints do not exhibited corrosion resistance improving effect, there is a problem that the thickness of the antirust coating increases.
Japanese Unexamined Patent Publication No. 11-293200 Japanese Unexamined Patent Publication No. 2004-359800 Japanese Patent No. 4111531

INDUSTRIAL APPLICABILITY According to the present invention, the rust preventive coating of the rust preventive paint can be colored in a bright color without being colored by another coloring paint, and is high due to the same thickness as the uncolored rust preventive coating. An object of the present invention is to provide a colored rust preventive coating, a rust preventive member having a rust preventive film, and a method for manufacturing the rust preventive member, which realizes corrosion resistance and white rust resistance.

In order to achieve the above object, the present inventor blends a colored pigment into the rust-preventive coating and also blends a colored aluminum powder to obtain a coating that develops vivid colors while maintaining good rust-preventive properties. I got the finding that it can be formed.
The present invention has been completed based on the above findings, and includes the following items.

(1) each other and a laminate structure consisting of two layers of film in contact with the physician, of the coating of two layers, zinc powder content in the first coating composition used to form the first coating of the inner layer side but greater than the zinc powder content in the second coating composition used to form the second coating layer side, the second coating composition, which contains a colored pigment and colored aluminum powder The total of the content of the zinc-based powder in the first coating composition and the content of the zinc-based powder in the second coating composition is 15% by mass or more and 30% by mass or less, and the first The content of the zinc-based powder in the second coating composition is 20% by mass or less, and the organic titanate compound is an organic compound represented by the general formula Ti (X) ₄ and an oligomer thereof. A chelating substituent containing methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, and tert-butoxy having 4 or less carbon atoms, lactate, triethanolaminate, acetylacetonate, acetoacetate, and ethylacetacetate. , And a rust preventive coating that is one or more functional groups selected from the group consisting of hydroxyl groups .
(2) The rust preventive coating according to (1), wherein the content of the zinc-based powder in the second coating composition is 1 to 15% by mass.
(3) The rust preventive coating according to (1) or (2), wherein the first coating composition and the second coating composition contain an organosilicon compound.
(4) The rust preventive according to any one of (1) to (3), wherein the first coating composition contains uncolored aluminum powder and does not contain a colored pigment or colored aluminum powder. Coating .
(5 ) The rust preventive coating according to any one of (1) to (4) , wherein the zinc-based powder, the colored aluminum powder, and the uncolored aluminum powder are scaly.

(6) A rust preventive member provided with the rust preventive film according to any one of (1) to (5) on a base material.
(7) A method for manufacturing a rust preventive member, comprising a step of forming a rust preventive film according to any one of (1) to (5) on a substrate.

Since the rust preventive film of the present invention is formed of a coating composition containing a colored pigment and a colored aluminum powder, it is possible to impart a vivid colored appearance as well as rust preventive properties. Therefore, since the object to be coated can be vividly colored only by the rust preventive film, the thickness of the colored rust preventive film can be made thinner than that in which the colored paint is applied. For example, it is possible to form a thin film having a good surface texture of about 10 to 20 μm, and even if this thin film is baked at a high temperature, cracks do not occur in the film. Therefore, it is possible to form a colored rust preventive film which is a thin film but has excellent corrosion resistance.
If the rust preventive film has two layers and the inner layer side is a rust preventive film formed of a rust preventive paint composition having a higher zinc content than the outer layer side, the corrosion resistance and the white rust resistance can be further improved. it can.

A coating composition containing a colored pigment and a colored aluminum powder (hereinafter, also referred to as “paint”) used for forming the colored rust preventive film of the present invention will be described.
(Paint composition)
The coating composition for forming the rust preventive film according to the present invention contains an organic silicon compound, an organic titanate compound, a metal powder composed of a zinc-based powder and a colored aluminum powder, a colored pigment and an organic solvent, and is required. Contains a small amount of additives.
Hereinafter, these components will be described in detail. In the following description,% is a mass% based on all paints unless otherwise specified.

(Organosilicon compound)
As the binder component in the rust preventive coating material of the present invention, an organosilicon compound and an organotitanate compound are used so that cracks do not occur even in the baking treatment at a high temperature.

Of these, the organosilicon compound is one or more selected from alkoxysilane and its hydrolyzate. The alkoxysilane is preferably a compound represented by the general formula (X') Si (X ") ₃ .

Here, X'is a lower alkoxy group such as hydroxy group, methoxy, ethoxy, isopropoxy, etc., a lower alkyl group such as methyl, ethyl, etc., a lower alkenyl group such as vinyl group, and further γ-glycidoxypropyl. , Γ-Methyloxypropyl, γ-mercaptopropyl, etc. are selected from functional group-containing lower alkyl groups. The X "is selected from a hydroxy group and an alkoxy group such as methoxy, ethoxy, isopropoxy, etc., and the three X's may be the same or different.

Specific examples of the alkoxysilane include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and the like. However, it is not limited to that. Various commercially available alkoxysilanes may be used as the silane coupling agent.

Among these alkoxysilanes, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane or oligomers thereof are preferable, and tetraalkoxysilanes having 3 or less carbon atoms or oligomers thereof are particularly preferable. When a condensation reaction is caused by the baking treatment, a film having a three-dimensional crosslinked structure can be formed, and the film strength is likely to be improved. In addition, since the volume shrinkage during condensation is relatively small, cracks are unlikely to grow.

The amount of the above-mentioned organosilicon compound is preferably 5 to 40% of the total paint. If it is less than 5%, the film strength tends to decrease, and if the amount added is even smaller, clear voids will be generated between the metal powders and the rust preventive function will also decrease. become. On the other hand, if it is added in excess of 40%, the dispersion concentration of the metal powder in the coating film is relatively lowered, so that the rust preventive function tends to be lowered. Further, since the overlapping area of the metal powders to be laminated is reduced, there is a possibility that the function of suppressing crack growth is lowered. A more preferable range is 10 to 35%, and a particularly preferable range is 15 to 35%.

(Organic titanate compound)
In the present invention, in order to improve the coating properties, an organic titanate compound, which is one or more compounds selected from the group consisting of a tetraalkyl silicate compound having an alkyl group having 3 or less carbon atoms and an oligomer thereof, is used as a medium. Add to some organic solvent. The organic titanate compound means an organic compound represented by the general formula Ti (X) ₄ and an oligomer thereof. Here, X is selected from a hydroxyl group, a lower alkoxy group, and a chelating substituent, and the four Xs may be the same or different.

The lower alkoxy group means an alkoxy group having 6 or less carbon atoms, preferably 4 or less carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, and the like.

The chelating substituent means a group derived from an organic compound having a chelating ability. Examples of such organic compounds include β-diketone such as acetylacetone, alkylcarbonylcarboxylic acids such as acetoacetic acid and esters thereof, hydroxy acids such as lactic acid, and alkanolamines such as triethanolamine. Specific examples of the chelating substituent include lactate, ammonium lactate, triethanolamineate, acetylacetonate, acetoacetate, ethylacetate acetate, and the like.

This organic titanate compound exhibits a high function with a small amount of addition as described later. That is, when the organosilicon compound is baked at a high temperature, the added organotitanate compound functions as a curing agent or a catalyst to promote a three-dimensional cross-linking reaction of the organosilicon compound. Therefore, the curing rate of the binder component is increased, and the growth of cracks is suppressed.

Further, the chemical bond between the organosilicon compound and the metal powder and the chemical bond between the organosilicon compound and the steel material as the base material are also promoted by the presence of the organosiliconate compound, and the bond strength is enhanced. Therefore, the interfacial peeling between the metal powder and the binder and the interfacial peeling between the steel material and the binder are suppressed, and the growth of cracks is suppressed.

The amount of the organic titanate compound added is preferably 0.05 to 5.0%. If the amount of the organic titanate compound is too small, the effect cannot be obtained and cracks are likely to occur, which may reduce the rust preventive property of the coating film. On the other hand, when it becomes excessive, it tends to absorb the humidity in the atmosphere and easily hydrolyze, and the pot life tends to be shortened. A more preferable range is 0.05 to 2%, and a particularly preferable range is 0.1 to 2%.

(Metal powder)
As the metal powder, zinc-based powder and aluminum powder, which have been conventionally used in zinc-rich anticorrosive paints, are used. In the present invention, the zinc-based powder means a metal powder containing zinc as a component, and also includes a zinc alloy powder. The colored aluminum powder means that a colored pigment is attached to the surface of a metal powder containing aluminum as a component. Here, the metal powder containing aluminum as a component contains aluminum powder and aluminum alloy powder as well as zinc-based powder. Therefore, the colored aluminum powder includes a colored aluminum alloy powder. Examples of zinc alloys include Zn-Ni, Zn-Sn, Zn-Fe, Zn-Al, Zn-Al-Mg, and the like.

When a coloring pigment is added, a colored rust preventive paint is obtained, and the coating of the colored rust preventive paint can be used for coloring. However, simply adding a coloring pigment does not result in a colored rust preventive paint that forms a rust preventive film that develops vivid colors. The present inventors have found that the metal powder blended in the rust preventive paint is one of the factors that reduce the vividness of the color development of the coating film, and that the reduction in vividness is particularly affected by the aluminum powder. It was. Then, by using the colored aluminum powder previously colored with the coloring pigment, it is possible to suppress the influence of the uncolored aluminum powder on the color development of the coating film. As described above, by replacing the aluminum powder with the colored aluminum powder and blending the colored pigment, the colored rust preventive paint can form a colored rust preventive film that develops a vivid color.

Unlike aluminum powder, zinc-based powder in metal powder has a small effect on the vividness of color development of the film. Therefore, the zinc-based powder can form a colored rust preventive film that develops a vivid color even if it is blended without being colored. By blending the zinc-based powder, the film formed by the rust preventive paint develops a vivid color and has a sufficient rust preventive effect due to the sacrificial anticorrosive action of zinc.

The shape of the metal powder as a raw material for the coating material is preferably a scale shape so as to have high corrosion resistance even if the thickness of the coating film is reduced. Due to the scaly shape, it is realized that the metal powder is laminated in the film in the thickness direction. This laminated structure suppresses the growth of cracks in the coating film due to shrinkage caused by the polymerization of the binder component, and prevents the generation of large cracks that expose the base material.

The average thickness of the scaly metal powder is 1/200 to 1/2 of the average thickness of the coating, and the average value of the major axis of the metal powder (the length of the longest part of the scaly shape) is the average of the coating. It is preferably 1/20 to 10 times the thickness. For example, when the coating film is about 10 μm, the average thickness of the scale-shaped metal powder is preferably 0.05 to 5 μm, and the average value of the major axis is preferably 0.5 to 100 μm.

Further, even under conditions in which the thickness of the coating film varies depending on the coating conditions of the paint, the average value of the major axis of the metal powder is in the range of 1.0 to 50 μm, particularly preferably 4.0 to 20 μm. When the average thickness of the scale shape is in the range of 0.05 to 1.0 μm, particularly preferably 0.05 to 0.5 μm, cracks are less likely to occur even by the baking treatment, and excellent rust prevention characteristics are obtained. A film having the above is obtained.

When the average value of the major axis is smaller than the above range, it becomes difficult to obtain a structure in which the scale-shaped metal powder is laminated in the coating film, and the effect of suppressing crack growth tends to be reduced. On the other hand, if it is larger than the above range, the distribution of the metal powder becomes sparse, which may adversely affect the rust prevention characteristics.

Further, when the average thickness of the scale shape is smaller than the above range, it is easily destroyed during the stirring and kneading work of the paint, the scale shape is hard to be formed, and the laminated structure is hard to be obtained. On the other hand, if it is larger than the above range, it becomes difficult to obtain a structure in which a plurality of metal powders are laminated in the thickness direction of the coating film, and the effect of suppressing the growth of cracks may be reduced.

The composition ratio of the metal powder in the coating material is preferably in the range of 5 to 60% in mass% with respect to the total coating material, and more preferably 5 to 40%. If the amount is too large, it becomes difficult to apply the paint in a thin film form, and the strength of the coating film decreases. On the contrary, if the amount is too small, cracks tend to develop and the rust preventive function of the coating film deteriorates.

(Organic solvent)
When the rust preventive coating material of the present invention contains an organic solvent during the coating operation, it is possible to obtain a film having good liquid compatibility with the member to be coated and having high adhesion. Further, with respect to various additives added at the time of coating, a wide range of additives can be used by containing an organic solvent.

Suitable organic solvents include alcohols such as methanol, ethanol, propanol, isopropanol, butanol, hexanol, methoxybutanol and methoxymethylbutanol, esters such as acetates and propionic acid esters of these alcohols, ethylene glycol and diethylene glycol. , Triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and other glycols, and ethers such as monomethyl ether, monoethyl ether and monobutyl ether of these glycols are exemplified. In addition, hydrocarbons such as toluene, xylene, mineral spirit, and solvent naphtha may be used. These may be used alone or as a mixture of several types.

The amount of the organic solvent varies depending on the working environment, but is preferably 10 to 60% of the total coating material, more preferably 15% to 45%, and particularly preferably 20 to 30%. If it exceeds this range, it may be difficult to make a thin film, or it may be difficult for the metal powder to form a laminated structure in the film, and it may be difficult to obtain a desired film although it is related to the content of other components. sell.

(Coloring pigment)
As the coloring pigment, generally used organic pigments and inorganic pigments can be used, but organic pigments are preferable because of the vividness of the color tone. Examples of the organic pigment include permanent red, first yellow, and phthalocyanine green, and examples of the inorganic pigment include titanium dioxide, Bengara, Prussian blue, iron oxide, and carbon black. These may be used alone or as a mixture of several types. From the viewpoint of improving the dispersibility in the coating composition, the coloring pigment is preferably blended as a pigment dispersion in which the coloring pigment is dispersed in the dispersant in advance. The blending amount of the pigment dispersion is preferably 5 to 60% by mass, more preferably 10 to 40% by mass of the rust preventive coating material.

(Other additives)
The rust preventive paint of the present invention may contain various additives generally used in the paint, if necessary. Examples of such additives include thickeners, rust preventive pigments, colloidal silica fine particles, and the like.

Examples of the thickener include fatty acid amide, polyamide, polyethylene oxide, hydroxypurple cellulose, and silicate-based inorganic thickeners.
Examples of rust preventive pigments include zinc phosphate, magnesium phosphate, zinc molybdate, aluminum phosphate, and the like.

The colloidal silica fine particles are sol-like silica particles having a particle size of more than 1 μm, and have the effect of improving the corrosion resistance and the film strength of the film, similarly to the above-mentioned silicon compound. Examples of the colloidal silica fine particles include an organosilica sol in which colloidal silica is dispersed in an organic solvent (for example, Snowtex manufactured by Nissan Chemical Industries, Ltd.), fumed silica (gas phase silica), and the like.

In addition, conventional paint additives such as wetting agents and antifoaming agents can also be contained in the paint of the present invention.
In total, these other additives are preferably added in an amount in the range of 0.1-10% of the total paint. If it is less than 0.1%, the effect of the additive may not be obtained, and if it exceeds 10%, the composition ratio of the metal powder and the binder component, which are the main ingredients, relatively decreases, which is a basic characteristic of rust prevention. The characteristics may deteriorate.

As each of the components constituting the rust preventive paint described above, one kind or two or more kinds can be used. The rust preventive coating material is prepared by sufficiently stirring and mixing each of the above-mentioned components and uniformly dispersing the metal powder in the liquid.

The steel member which is a base material to which this rust preventive paint can be applied includes all steel members, from steel plates, bars, steel pipes and shaped steels to molded products and even small members such as bolts. The steel member may be subjected to a treatment widely used as a pre-coating treatment for improving coating adhesion and corrosion resistance, such as shot blasting treatment and phosphate coating treatment. A rust preventive member is formed by forming a rust preventive film on the surface of the steel member using a rust preventive paint.

The step of forming the rust preventive film on the substrate can be performed by using a general method. For example, it can be carried out by a conventional method such as roll coating, spraying, brush coating, dipping, etc., and an appropriate coating method may be selected according to the form of the member. The coating is preferably carried out so that the film thickness formed after the heat treatment is in the range of 2 to 30 μm.

The heat treatment (baking) after coating is performed at 150 to 400 ° C. for 10 to 120 minutes. By the heat treatment, the organosilicon compound undergoes a condensation reaction using the organotitanate compound as a curing agent or a catalyst, and a film containing a large amount of metal powder is formed on the surface of the steel member. Prior to the heat treatment, preheating may be performed for drying.

The steel member coated with the coating material of the present invention thus exhibits a rust preventive effect for a long period of time even if it is used as it is, but it is also possible to further apply the coating if desired.

(Rust-proof coating with laminated structure)
The rust preventive coating of the present invention can also be implemented as a rust preventive coating having a laminated structure composed of two layers of coatings in contact with each other.
The content (Zn1) of the zinc-based powder contained in 100% by mass of the first coating composition forming the first film on the inner layer side is 20 to 60 mass by mass from the viewpoint of improving the corrosion resistance of the rust preventive film. % Is preferable, 30 to 50% by mass is more preferable, and 35 to 45% by mass is further preferable. From the same viewpoint, the total content (Al1) of the aluminum powder (Al1), which is the sum of the aluminum powder whose surface is colored (colored aluminum powder) and the uncolored aluminum powder (uncolored aluminum powder), is preferably 1 to 40% by mass. , 2 to 20% by mass, more preferably 3 to 10% by mass. The first coating composition may contain only uncolored aluminum powder and may not contain colored aluminum powder. This is because if the second coating composition forming the second coating film on the outer layer side contains the colored aluminum powder, the color development of the rust preventive coating film, which is a laminated body, becomes good. For the same reason, the first coating composition that does not contain the colored aluminum powder may not contain the colored pigment.

The above-mentioned preferable content means the content as an aluminum powder. For example, when a slurry of aluminum powder in which aluminum powder is dispersed in a solvent (hereinafter, also referred to as "aluminum slurry") is used, it means the content of the aluminum powder contained in the aluminum slurry, not as the aluminum slurry. To do. The colored aluminum powder is one in which the surface of the aluminum powder is covered with a coloring pigment. Therefore, the content of the colored aluminum powder means the content of the aluminum powder, the colored pigment, and the non-volatile resin used for bonding the two together.

The content (Zn2) of the zinc-based powder contained in 100% by mass of the second coating composition forming the second coating film on the outer layer side is 1 to 40 mass by mass from the viewpoint of improving the corrosion resistance of the rust preventive coating. % Is preferable, 1 to 30% by mass is more preferable, and 1 to 15% by mass is further preferable. From the same viewpoint, the total aluminum powder content (Al2) of the colored aluminum powder and the uncolored aluminum powder is preferably 1 to 50% by mass, more preferably 2 to 40% by mass, and 3 to 30% by mass. More preferred. From the viewpoint of producing a dull color, the aluminum powder in the second coating composition is preferably a colored aluminum powder and does not contain an uncolored aluminum powder. The second coating composition preferably contains a coloring pigment in addition to the colored aluminum powder because the color development of the rust preventive coating which is a laminated body is improved.

The content of the zinc-based powder contained in the coating composition obtained by combining the first and second coating compositions is preferably 10% by mass or more and 60% by mass or less from the viewpoint of improving the corrosion resistance of the rust preventive coating. It is more preferably 15 to 40% by mass, further preferably 15 to 30% by mass.
The content of the zinc-based powder contained in the coating composition means the content of the zinc-based powder based on the total amount of the first and second coating compositions. For example, a first coating composition having a zinc-based powder content of 38% by mass (Zn1 is 38% by mass) and a second coating composition having a zinc-based powder content of 8% by mass (Zn2). When the rust-preventive coating composed of the first and second coating films is formed by using the same amount of 8% by mass), the content of the zinc-based powder contained in the coating composition is 23% by mass (= (38% by mass). % + 8% by mass) ÷ 2).

From the viewpoint of improving the corrosion resistance of the rust preventive coating, the zinc-based powder content (Zn1 and Zn2) in each of the first and second coating compositions is preferably Zn1 larger than Zn2. Zn1 / Zn2 is preferably 2 to 60, more preferably 3 to 40, and even more preferably 3 to 25.

From the viewpoint of improving the appearance of the rust preventive coating, the total content of the metal powder in the first coating composition (Zn1 + Al1) is the total content of the metal powder in the second coating composition (Zn2 + Al2). That is, it is preferably (Zn1 + Al1)> (Zn2 + Al2), more preferably (Zn1 + Al1)> 1.5 × (Zn2 + Al2), and (Zn1 + Al1)> 1.8 × (Zn2 + Al2). Is even more preferable.

Hereinafter, the present invention will be further described with reference to Examples, but the present invention is not limited to the aspects of the Examples.
1. 1. Preparation of test pieces According to the formulation (parts by mass) shown in Table 1, each component was sufficiently mixed by stirring together for 3 hours using a high-speed paint stirrer to prepare a paint composition (in each table below). (Indicated as "composition") 1 to 8 were prepared.

The scale-shaped zinc-based powder was prepared as follows.
100 parts by weight of the metallic zinc-based powder having an average particle size of 5 μm was dispersed in 200 parts by weight of the mineral spirit, and a small amount of fatty acid was further added to prepare a slurry having a dispersed concentration of the metallic zinc-based powder of about 30% by weight. This slurry is pulverized with a bead mill (Star Mill ZRS manufactured by Ashizawa Finetech Co., Ltd.), and the treated slurry is evaporated and dried under reduced pressure so that the center value of the diameter distribution is 10 μm and the center value of the thickness distribution is A scale-shaped zinc-based powder of 0.3 μm was obtained.

The following were used as the scale-shaped aluminum powder and the colored aluminum powder.
-Uncolored aluminum powder (scale shape): Aluminum slurry consisting of 65% by mass of uncolored aluminum powder (scale shape) and 35% by mass of mineral spirit, Alpaste 0200M (product name, average diameter 10 μm) manufactured by Toyo Aluminum K.K. , Average thickness 0.2 μm)
-Red aluminum powder (scale shape): Aluminum slurry consisting of 50% by mass of red aluminum powder (scale shape) and 50% by mass of mineral spirit, Colored Alpaste D451RE (product name, average diameter 11 μm) manufactured by Toyo Aluminum K.K.
-Yellow aluminum powder (scale shape): Aluminum slurry consisting of 55% by mass of yellow aluminum powder (scale shape) and 45% by mass of mineral spirit, colored alpaste D452YE manufactured by Toyo Aluminum Co., Ltd. (product name, average diameter 11 μm) )
-Blue aluminum powder (scale shape): Aluminum slurry consisting of 55% by mass of blue aluminum powder (scale shape) and 45% by mass of mineral spirit, Colored Alpaste D452BL (product name, average diameter 11 μm) manufactured by Toyo Aluminum K.K. )

The following components were used as the other components shown in Table 1.
-Ethyl polysilicate: Ethyl silicate 40 manufactured by Corcote Co., Ltd. (product name)
-Tetrabutoxytitanium polymer: TBT polymer B-10 (product name) manufactured by Nippon Soda Co., Ltd.
-Red pigment dispersion: NX-032 Red (product name) manufactured by Dainichiseika Kogyo Co., Ltd.
-Yellow pigment dispersion: NX-011 Yellow manufactured by Dainichiseika Kogyo Co., Ltd. (product name)
-Blue pigment dispersion: EMU Blue 870AF-1 (product name) manufactured by Toyo Color Co., Ltd.
・ Dispersant (polyethylene oxide): Made by Kusumoto Kasei Co., Ltd.
・ Thickener (organic bentonite): Made by Nippon Organic Clay Co., Ltd.

(Single layer)
[Example 1]
The coating composition 1 was applied to a mild steel sheet that had been degreased and washed in advance with a bar coater, and heat-treated at 280 ° C. for 30 minutes to prepare a film having a film thickness of 20 μm.
[Example 2]
A coating composition 2 was used instead of the coating composition 1 of Example 1, and a coating film having a film thickness of 20 μm was prepared in the same manner.
[Example 3]
A coating composition 3 was used instead of the coating composition 1 of Example 1, and a coating film having a film thickness of 20 μm was prepared in the same manner.

[Comparative Example 1]
A coating composition 7 was used instead of the coating composition 1 of Example 1, and a coating film having a film thickness of 20 μm was prepared in the same manner.
[Comparative Example 2]
A coating composition 8 was used instead of the coating composition 1 of Example 1, and a coating film having a film thickness of 20 μm was prepared in the same manner.

(bilayer)
[Example 4]
The coating composition 1 was applied to a mild steel sheet that had been degreased and washed in advance with a bar coater, and heat-treated at 280 ° C. for 30 minutes to prepare a film having a film thickness of 10 μm. The coating composition 1 was further applied to the surface of the produced coating film with a bar coater and heat-treated at 280 ° C. for 30 minutes to prepare a coating film having a film thickness of 10 μm. In this way, a laminated film having a film thickness of 20 μm as a whole was produced.
[Example 5]
A coating composition 2 was used instead of the coating composition 1 of Example 4, and a laminated coating having a film thickness of 20 μm as a whole was prepared in the same manner.
[Example 6]
A coating composition 3 was used instead of the coating composition 1 of Example 4, and a laminated coating having a film thickness of 20 μm as a whole was prepared in the same manner.

[Example 7]
The coating composition 6 was applied to a mild steel sheet that had been degreased and washed in advance with a bar coater, and heat-treated at 280 ° C. for 30 minutes to prepare a film having a film thickness of 10 μm. The coating composition 1 was further applied to the surface of the prepared coating film with a bar coater and heat-treated at 280 ° C. for 30 minutes to prepare a coating film having a film thickness of 10 μm. In this way, a laminated film having a film thickness of 20 μm as a whole of the two layers was produced.
[Example 8]
A coating composition 2 was used instead of the coating composition 1 of Example 7, and a laminated coating having a film thickness of 20 μm as a whole was prepared in the same manner.
[Example 9]
A coating composition 3 was used instead of the coating composition 1 of Example 7, and a laminated coating having a film thickness of 20 μm as a whole was prepared in the same manner.
[Example 10]
A coating composition 4 was used instead of the coating composition 1 of Example 7, and a laminated coating having a film thickness of 20 μm as a whole was prepared in the same manner.
[Example 11]
A coating composition 5 was used instead of the coating composition 1 of Example 7, and a laminated coating having a film thickness of 20 μm as a whole was prepared in the same manner.

[Comparative Example 3]
A coating composition 6 was used instead of the coating composition 1 of Example 4, and a laminated coating having a film thickness of 20 μm was prepared in the same manner.
[Comparative Example 4]
A coating composition 7 was used instead of the coating composition 1 of Example 4, and a laminated coating having a film thickness of 20 μm was prepared in the same manner.
[Comparative Example 5]
A coating composition 8 was used instead of the coating composition 1 of Example 4, and a laminated coating having a film thickness of 20 μm was prepared in the same manner.

2. 2. Evaluation Method (1) Color Tone Whether or not the mild steel sheet having a film formed on its surface can be colored without turbidity by the above method was visually determined using the following criteria.
◯: There is no turbidity and the color is beautiful.
X: It is turbid and cannot be colored cleanly.
(2) White rust corrosion resistance Salt spray test The progress was observed according to JIS Z 2371, and the evaluation was made based on the time from the start of the test until the white rust generation area ratio became 10% or more.
(3) Scratch and corrosion resistance A mild steel plate having a rust preventive paint film formed on its surface was used as a test piece. A cross cut was made with a cutter knife so that the test piece reached the base material (mild steel plate), and used as an evaluation test piece.
The corrosion resistance was evaluated by observing the progress according to the salt spray test JIS Z 2371 and evaluating the time from the start of the test to the occurrence of red rust on the cross-cut portion of the evaluation test piece.

3. 3. Test Results Tables 2 and 3 show the results of evaluating (1) color tone, (2) white rust corrosion resistance, and (3) scratch corrosion resistance using the evaluation method described above.

上記の表に示すとおり、着色顔料としての顔料分散体と着色アルミニウム粉末とを併用することにより、実施例１〜３の防錆塗料により濁りのない着色を実現することができた。すなわち鮮やかに発色する被膜を形成することができた。また、防錆塗料の被膜は、傷つき耐食性も良好であった。

As shown in the above table, by using the pigment dispersion as the coloring pigment and the colored aluminum powder in combination, the rust preventive coatings of Examples 1 to 3 could realize coloring without turbidity. That is, it was possible to form a vividly colored film. In addition, the coating of the rust preventive paint had good scratch resistance and corrosion resistance.

上記の表に示すとおり、同じ組成物を用いた場合、膜厚が同じであれば、防錆被膜を単層（２０μｍ）とするか二層（１０μｍ＋１０μｍ）とするかによって、傷つき耐食性は変わらなかった（実施例１〜３と４〜６とを対比）。
異なる組成物を用いて防錆被膜を作製した実施例７〜１２はいずれも、極めて高い白錆耐食性および傷付耐食性を示した。これら実施例７〜１２はいずれも、塗料組成物６を用いた第一層の上に、さらに塗料組成物６を用いて第二層を作製した比較例３の防錆被膜よりも高い白錆耐食性および傷付耐食性を示した。このことから、第二の被膜に用いられる第二の塗料組成物の亜鉛系粉末の含有量は、第一の被膜に用いられる第一の塗料組成物の亜鉛系粉末の含有量よりも小さいことが好ましいことが分かった。
また、外側の被膜のみを着色アルミ及び着色顔料で着色した実施例７〜１２の防錆被膜は、二層とも着色アルミ及び着色顔料で着色した実施例４〜６の防錆被膜同様、濁りがないきれいな色に着色することができた。

As shown in the above table, when the same composition is used, if the film thickness is the same, the scratch and corrosion resistance does not change depending on whether the rust preventive coating is a single layer (20 μm) or two layers (10 μm + 10 μm). (Compare Examples 1 to 3 and 4 to 6).
Examples 7 to 12 in which rust preventive coatings were prepared using different compositions all showed extremely high white rust corrosion resistance and scratch corrosion resistance. In each of these Examples 7 to 12, white rust higher than that of the rust preventive film of Comparative Example 3 in which the second layer was further prepared by using the coating composition 6 on the first layer using the coating composition 6. It showed rust resistance and scratch corrosion resistance. From this, the content of the zinc-based powder of the second coating composition used for the second coating film is smaller than the content of the zinc-based powder of the first coating composition used for the first coating film. Was found to be preferable.
Further, the rust-preventive coatings of Examples 7 to 12 in which only the outer coating was colored with colored aluminum and a coloring pigment were turbid like the rust-preventing coatings of Examples 4 to 6 in which both layers were colored with colored aluminum and a coloring pigment. I was able to color it in no beautiful color.

INDUSTRIAL APPLICABILITY The present invention is useful as a rust preventive paint applied to a steel plate for press molding of precision equipment and automobiles because it can impart a high rust preventive function and give a bright color even to a thin film.

Claims (7)

A laminated structure consisting of two layers of film in contact with each other physician, of the coating of two layers, the zinc powder content in the first coating composition used to form the first coating of the inner side, an outer layer It is larger than the zinc-based powder content in the second coating composition used for forming the second coating on the side, and the second coating composition contains a colored pigment and a colored aluminum powder .
The total content of the zinc-based powder in the first coating composition and the content of the zinc-based powder in the second coating composition is 15% by mass or more and 30% by mass or less.
The content of the zinc-based powder in the second coating composition is 20% by mass or less.
The first coating composition and the second coating composition contain an organic titanate compound, and the organic titanate compound is an organic compound represented by the general formula Ti (X) ₄ and an oligomer thereof. , X comprises an alkoxy group having 4 or less carbon atoms of methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, and tert-butoxy, lactate, triethanolamineate, acetylacetonate, acetoacetate, and ethylacetacetate. A rust-preventive coating that is one or more functional groups selected from the group consisting of chelating substituents and hydroxyl groups . The rust preventive coating according to claim 1, wherein the content of the zinc-based powder in the second coating composition is 1 to 15% by mass. The rust preventive coating according to claim 1 or 2 , wherein the first coating composition and the second coating composition contain an organosilicon compound . The rust preventive coating according to any one of claims 1 to 3, wherein the first coating composition contains an uncolored aluminum powder and does not contain a colored pigment and a colored aluminum powder. The rust preventive coating according to any one of claims 1 to 4 , wherein the zinc-based powder, the colored aluminum powder, and the uncolored aluminum powder are scaly. A rust preventive member provided with the rust preventive film according to any one of claims 1 to 5 on a base material. A method for manufacturing a rust preventive member, comprising a step of forming the rust preventive film according to any one of claims 1 to 5 on a base material.