JP2017122186A - Coating composition and coated member prepared therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition that expresses better corrosion resistance than the conventional coating composition containing only Zn metal powder, and a coated member prepared therewith.SOLUTION: A coating composition contains binder resin, Zn metal powder, and condensation aluminium phosphate containing Mg. A content of the Zn metal powder is 65-85 mass% relative to the coating solid content, and a content of the condensation aluminium phosphate containing Mg is 1-10 mass% relative to the coating solid content.SELECTED DRAWING: None

Description

  The present invention relates to a coating composition and a coated member using the same.

  Various anticorrosion coating compositions are used for the base material for anticorrosion and rust prevention, for example, corrosion prevention and rust prevention of steel materials. Among these, zinc dust-containing paints containing zinc in the form of powder particles and fine flakes typified by zinc rich paints are generally widely used. This zinc powder-containing paint utilizes the fact that zinc is electrically lower than iron and protects the steel sheet coated with the paint while gradually consuming the zinc powder contained in the coating film.

  In zinc-rich paints, inorganic zinc-rich paints that use alkoxysilicates as binder resins and organic zinc paints that use epoxy resins as binder resins dominate, and both of these are solvent-based zinc-based solvents that use organic solvents as solvents. Rich paint.

  In recent years, from the viewpoints of air pollution prevention and resource saving, the conversion from solvent-based zinc rich paints to water-based zinc rich paints containing a small amount of organic solvent in water or water has been attempted.

  Water-based zinc-rich paints are roughly classified into inorganic-type zinc rich paints and organic-type zinc-rich paints, similarly to solvent-based zinc rich paints. The inorganic zinc rich paint uses an alkali silicate as a binder resin, and the organic zinc rich paint uses an epoxy resin as a binder resin.

  These zinc rich paints are generally used for purposes such as cutting of zinc-plated steel sheets, punched edges, arc welding and other parts where zinc is not present on steel sheets, bridges, plants, Rust prevention of various onshore steel structures such as tanks and offshore steel structures.

  In order to improve the antirust property of such zinc rich paints, it has been attempted to use various pigment powders in addition to the binder resin and zinc powder as the composition.

  For example, Patent Document 1 discloses a zinc rich paint composition containing a molybdenum-containing pigment as a pigment powder, and Patent Document 2 discloses a zinc rich paint composition containing a phosphate pigment or feldspar as a pigment powder. Is a zinc rich paint composition containing ferric oxide and molybdenum compounds as pigment powder, and Patent Document 4 is a zinc rich paint composition containing non-aqueous cyclic aluminum metaphosphate as a pigment powder. No. 5 discloses zinc rich paint compositions containing aqueous aluminum as a pigment powder.

  Patent Document 6 discloses a coating composition that does not contain zinc powder and contains elements contained from Mg, Si, Cd, Ba, Ga, In, Sn, and Ri, aluminum, alloy powder, and mixed powder. ing.

  Further, Patent Document 7 discloses an automobile chassis member made of a high-strength Fe-Al-based plated steel sheet in which an Fe-Al-based alloy layer is also present in the vicinity of the bead toe of arc welding. Even if the plating evaporates near the bead toe, the plated metal melted around it quickly spreads to the bead toe in the process of lowering the temperature after welding, so that an automobile chassis member with excellent corrosion resistance at the arc weld can be obtained. It is disclosed.

JP-A-5-339521 Japanese Patent Laid-Open No. 6-200188 JP-A-8-60039 JP-A-11-116856 JP 2014-31505 A JP 2014-31505 A Japanese Patent Laying-Open No. 2015-3340

  As explained above, automotive parts, machine parts, home appliance parts, building materials, etc., and cutting of steel sheets that have been galvanized, punched ends, parts where zinc is not present on the steel sheets by welding such as arc welding, Furthermore, in order to improve the corrosion resistance of various onshore steel structures such as bridges, plants, tanks, and offshore steel structures, a coating is formed on the target part (for example, repair part) to increase the corrosion resistance of the target member. There is a need.

  However, as a result of investigations by the present inventors, in the inventions disclosed in Patent Documents 1 to 5, the effect of suppressing rust generated from the coated portion for a long time is not sufficient, so that rust can be suppressed for a long time. Inevitably increases the thickness of the film to be formed, increasing the cost of the rust prevention treatment. For this reason, it is necessary to further improve the corrosion resistance of the zinc rich paint composition itself.

  In the invention disclosed in Patent Document 6, since the coating composition does not contain zinc dust, the sacrificial anticorrosive ability to the Fe of the base material is not sufficient, so the film has to be thickened and rust prevention is required. Processing costs increase. For this reason, it is necessary to further improve the corrosion resistance of the zinc rich paint composition itself.

  Furthermore, in the invention described in Patent Document 7, since the plating component wets and spreads in the vicinity of the arc welded part, the amount of plating attached in the vicinity of the arc welded part also decreases, and the long-term corrosion resistance in the vicinity of the arc welded part decreases. Therefore, sufficient corrosion resistance cannot be obtained as a whole.

  This invention is made | formed in view of such a subject which the prior art has, and even if it coats with a thin film rather than the coating composition containing zinc-type metal powder, it can express favorable corrosion resistance. It aims at providing a coating composition and a coating member using the same.

The present invention is listed below.
(1) A coating composition containing a binder resin, a Zn-based metal powder, and a condensed aluminum phosphate containing Mg, wherein the content of the Zn-based metal powder is based on the solid content of the coating composition The paint composition is 65 to 85% by mass, and the content of the condensed aluminum phosphate containing Mg is 1 to 15% by mass with respect to the solid content of the paint composition.

(2) The coating composition according to item 1, wherein the condensed aluminum phosphate containing Mg is a mixture of magnesium hydroxide and aluminum dihydrogenphosphate.
(3) The coating composition according to item 2, wherein the ratio of the mixture of magnesium hydroxide and aluminum dihydrogen tripolyphosphate is 1: 2 to 8 by mass ratio.

(4) The coating composition according to 1, wherein the condensed aluminum phosphate containing Mg is aluminum dihydrogen tripolyphosphate containing Mg.
(5) The coating composition according to any one of 1 to 4, wherein the Zn-based metal powder includes at least one metal powder selected from Al, Mg, and Si.
(6) A coated member in which a coating composition according to any one of 1 to 5 is coated on a part or the entire surface of a molding material.
(7) A coated member having a coating film of the coating composition according to any one of items 1 to 5 on a part or the entire surface of the molding material.

  ADVANTAGE OF THE INVENTION According to this invention, even if it coats with a thin film rather than the coating composition containing zinc-type metal powder, the coating composition which expresses favorable corrosion resistance, and a coating member using the same are provided.

The present invention will be described.
The coating composition according to the present invention is a coating composition containing a binder resin, a Zn-based metal powder, and condensed aluminum phosphate containing Mg. The content of the Zn-based metal powder is 65% by mass to 85% by mass with respect to the solid content of the paint, and the content of the condensed aluminum phosphate containing Mg is 1% by mass to 10% with respect to the solid content of the paint. It is below mass%.

(1-1) Zn-based metal powder Zn-based metal powder is used as a rust preventive pigment for preventing rusting of a steel material in a coating film. As the Zn-based metal powder, those usually used in zinc rich paint can be used, and also can be used in compounds and mixtures with elements other than Zn.

  Further, Zn—Mg alloy powder and Zn—Al alloy powder containing Mg, Al and Si are preferable because the corrosion resistance is further improved. Furthermore, it is more preferable that the Zn-Al-Si alloy powder, the Zn-Mg-Al alloy powder, and the Zn-Mg-Al-Si alloy powder further improve the corrosion resistance.

  Examples of the form of the Zn-based metal powder include powder and flakes. From the viewpoint of sedimentation property and coating workability of the coating composition, the powder having an average particle diameter of 2 to 14 μm, more preferably 3 to 10 μm is preferable. Alternatively, the flakes have an average diameter of 3 to 25 μm and a thickness of 0.5 to 3 μm.

  There are two anticorrosion mechanisms for zinc rich paint applied to steel materials: “barrier anticorrosion” and “zinc sacrificial anticorrosion”. Barrier anticorrosion is to prevent the generation of rust mainly by blocking oxygen, moisture, and the like, which are corrosion factors, by the binder component in the coating film. In the sacrificial corrosion protection of zinc, zinc, which has a lower potential than iron, easily reacts with water, which is a corrosion factor, and the zinc compound formed by the reaction forms a dense oxide film on the surface of the steel material. It is a barrier.

  The content of the Zn-based metal powder is preferably 65% by mass or more and 85% by mass or less based on the solid content of the paint for the reason described above. If the content of the Zn-based metal powder is less than 65% by mass, the sacrificial anticorrosive ability of zinc may be insufficient and the corrosion resistance may be reduced. On the other hand, if the content of the Zn-based metal powder exceeds 85% by mass The binder ratio is lowered, which may result in insufficient barrier anticorrosive ability and lower corrosion resistance, and may lower coating film adhesion due to a decrease in the cohesive strength of the coating film. In order to improve the corrosion resistance while achieving both barrier anticorrosion and sacrificial anticorrosion of zinc, the content of the Zn-based metal powder is more preferably 70% by mass or more and 80% by mass or less with respect to the solid content of the paint.

(1-2) Condensed aluminum phosphate containing Mg Examples of condensed aluminum phosphate containing Mg include magnesium-treated product of aluminum dihydrogen phosphate, magnesium oxide of aluminum dihydrogen phosphate, magnesium hydroxide mixture, etc. Is done.

  By including condensed aluminum phosphate containing Mg in the resin coating, when water enters from the surface of the coating, the vicinity of the magnesium compound becomes an alkaline atmosphere. As a result, Zn-based metal powder Zn and Mg Condensed aluminum phosphate reacts to form Zn-Mg, Zn-phosphate compound composite oxides and composite compounds, while suppressing excessive sacrificial corrosion protection of zinc, and these composite compounds, phosphate compounds, magnesium It is considered that the compound exhibits excellent corrosion resistance by protecting the surface of the substrate (molded material such as steel).

  Examples of the magnesium-treated product of aluminum dihydrogen tripolyphosphate include K-WHITE G-105, G-110, and # 450H manufactured by Teika Co., Ltd.

  As a magnesium oxide and magnesium hydroxide mixture of aluminum dihydrogen tripolyphosphate, a mixture of magnesium aluminum trihydrogen phosphate and magnesium hydroxide, which are commercially available reagents, listed in the K-WHITE series manufactured by Teika Co., Ltd. Is exemplified.

  It is preferable that aluminum dihydrogen triphosphate and magnesium oxide or magnesium hydroxide are mixed at a mass ratio of 95: 5 to 80:20. When the ratio of aluminum dihydrogen phosphate to aluminum exceeds 95, the presence ratio of magnesium oxide or magnesium hydroxide in the vicinity of aluminum dihydrogen phosphate, Zn-based metal powder when the film is formed is good. On the other hand, if the ratio of aluminum dihydrogen phosphate is less than 80, the amount of magnesium oxide or magnesium hydroxide is excessive with respect to aluminum dihydrogen phosphate, resulting in good corrosion resistance. May not develop.

  It is more preferable in terms of corrosion resistance that aluminum dihydrogen triphosphate and magnesium oxide or magnesium hydroxide are mixed at a mass ratio of 90:10 to 85:15, and aluminum trihydrogen phosphate and hydroxide are mixed. A mixture of magne is more preferable from the viewpoint of corrosion resistance.

  Among the condensed aluminum phosphates containing Mg, magnesium treated with tripolyaluminum dihydrogen phosphate is the closest to aluminum dihydrogen triphosphate in terms of magnesium treatment, rather than magnesium oxide and magnesium hydroxide mixed with aluminum dihydrogen tripolyphosphate. Since a thing exists, it is more preferable from a corrosion-resistant viewpoint.

  The content of the condensed aluminum phosphate containing Mg is preferably 1% by mass or more and 10% by mass or less with respect to the solid content of the paint for the reason described above. If the content of the condensed aluminum phosphate containing Mg is less than 1% by mass, the absolute amount of the condensed aluminum phosphate containing Mg relative to the Zn-based metal powder is insufficient, so that a sufficient rust prevention effect cannot be obtained. Corrosion resistance may be reduced.

  On the other hand, when the content of the condensed aluminum phosphate containing Mg exceeds 15% by mass, the binder ratio is lowered, the barrier anticorrosive ability becomes insufficient, and the corrosion resistance may be lowered. There is a possibility that the adhesiveness of the coating film is lowered due to the decrease in the thickness. In order to improve the corrosion resistance while achieving both barrier anticorrosion and sacrificial anticorrosion of zinc, the content of the condensed aluminum phosphate containing Mg is 2% by mass or more and 10% by mass or less based on the solid content of the paint. Is more preferable.

(1-3) Binder Resin As the binder resin according to the present invention, any aqueous or solvent binder resin may be used. In view of the environment, it is preferable to use a water-based binder resin rather than a solvent-based one.

  Examples of the aqueous binder resin include a combination of an epoxy resin emulsion and an amine resin emulsion, an alkoxysilane, an acrylic resin emulsion, a urethane resin emulsion, and a polyester resin emulsion.

In addition, you may add a silane coupling agent, a Zr coupling agent, a Ti coupling agent, and water-soluble melamine resin as a hardening | curing agent to an acrylic resin emulsion, a urethane resin emulsion, and a polyester resin emulsion.
Examples of the solvent-based binder resin include an epoxy resin, a urethane resin, and a combination of a polyester resin and a melamine resin.

  As a combination of an epoxy resin emulsion and an amine resin emulsion, examples of the epoxy resin emulsion include bisphenol A type, halogenated bisphenol A type, novolac type, polyglycol type, and bisphenol F type. Of these, bisphenol A type and bisphenol F type are preferable from the viewpoint of corrosion resistance and adhesion to a substrate.

  The epoxy equivalent is preferably 100 to 1000 g / eq from the viewpoint of corrosion resistance and curability. If the epoxy equivalent is less than 100 g / eq, the flexibility of the coating film may be reduced, so that sufficient adhesion to the substrate may not be obtained. On the other hand, if the epoxy equivalent exceeds 1000 g / eq, leveling at room temperature may occur. Therefore, the film thickness difference between the coating films is likely to occur, and the corrosion resistance may be lowered. From the viewpoint of adhesion to the substrate and corrosion resistance, a range of 150 to 500 g / eq is more preferable.

  Examples of the epoxy resin include Yuka Resin KE-002, KE-116, and E-1022 manufactured by Yoshimura Oil Chemical Co., Ltd. The amine resin emulsion is used as a curing agent for the epoxy resin emulsion, and a polyamine resin emulsion having two or more amino groups per molecule is used.

  Examples of the polyamine resin include ethylenediamine, trimethylenediamine, tetramethylenediamine, and modified polyamine resins obtained by modifying the polyamine resin to amidation. The mixing ratio of the epoxy resin emulsion and the polyamine resin emulsion is preferably used in the range of 0.5 to 2.0 equivalents per 1 equivalent of epoxy.

  Examples of the alkoxysilane include commercially available tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisoporopoxysilane, tetrabutoxysilane, tetraisobutoxysilane and the like. An alkoxysilane having a lower alkyl group having 6 or less carbon atoms in the alkyl group is preferred. Moreover, the alkyl trialkoxysilane, the dialkyl dialkoxysilane etc. which have the performance similar to an alkoxysilane are illustrated.

  In order to promote the formation of the alkoxysilane film, a hydrolyzate or condensate of alkoxysilane can be used. These are obtained by adding water to alkoxysilane.

  Examples of the acrylic resin emulsion include acrylic acid resins such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, glycidyl acrylate, and modified acrylic resins such as silicon-modified acrylic resins. Is done. The molecular weight of the acrylic resin emulsion is preferably 5,000 to 1,000,000, and more preferably 10,000 to 1,000,000.

  When using a polyester resin emulsion, the molecular weight is preferably 10,000 to 30,000. If the molecular weight is less than 10,000, it may be difficult to ensure sufficient processability. On the other hand, when the molecular weight exceeds 30000, the binding site of the resin itself is lowered, and it may be difficult to ensure excellent adhesion with the electrodeposition coating film, and it may be crosslinked using a curing agent such as melamine. In the case of making it, the crosslinking reaction is not sufficiently performed, and the performance as a resin coating film may be deteriorated.

When using a urethane resin emulsion, the diameter of the urethane resin emulsion particles is preferably 10 to 100 nm, and more preferably 20 to 60 nm. If the emulsion particle size is too small, the cost increases. On the other hand, when the emulsion particle diameter is excessively large, the gap between the emulsions becomes large when a coating film is formed, and the barrier property as a resin coating film may be lowered.
Examples of the type of urethane resin include ether type, polycarbonate type, ester type, and acrylic graphite type. These may be used alone or in combination.

  The acrylic resin, polyester resin, and urethane resin emulsion may be a crosslinked resin having a crosslinked structure or a non-crosslinked resin having no crosslinked structure, but from the viewpoint of low-temperature film formation of a resin coating film. A non-crosslinked resin is preferred. As a crosslinking agent (curing agent) that imparts a crosslinked structure to the resin emulsion, a water-soluble crosslinking agent is preferable. Specifically, melamine, isocyanate, silane compound, zirconium compound, titanium compound and the like are preferable as the crosslinking agent.

It is preferable that the addition amount of a crosslinking agent is 5-30 mass parts with respect to 100 mass parts of solid content of a resin emulsion. When the addition amount of the cross-linking agent is less than 5 parts by mass, the cross-linking reaction with the resin is lowered, and the performance as a coating film may be insufficient. On the other hand, when the addition amount of the crosslinking agent is more than 30 parts by mass, the crosslinking reaction proceeds excessively, the resin coating becomes too hard, and the workability is lowered. In addition, the silane compound, zirconium compound, and titanium compound are further coated. Stability may be reduced.
It is preferable that content of binder resin is 10-60 mass% with respect to the total solid of a coating film.

  When the content of the binder resin is less than 10% by mass, the function as a binder is not exhibited, the cohesive force of the resin coating film is reduced, and the adhesion test and molding processing are performed inside the coating film. Breakdown (cohesive failure of the coating film) may occur easily.

On the other hand, when the content of the binder resin exceeds 60% by mass, the ratio of the pigment component contained in the resin coating is reduced, and both weldability, corrosion resistance before electrodeposition coating, and adhesion to the electrodeposition coating film are achieved. May be difficult to do.
The content of the binder resin expresses the binder function, and from the viewpoint of achieving both weldability, corrosion resistance before electrodeposition coating, and adhesion to the electrodeposition coating film, the resin coating film (total solid content of the coating film) More preferably, it is 15-50 mass%.

  The content of the binder resin is preferably 10 to 34% by mass with respect to the solid content of the coating material for the reason described above. When the content of the binder resin is less than 10% by mass, the binder ratio decreases, the barrier anticorrosive ability becomes insufficient, the corrosion resistance may decrease, and the coating is caused by the decrease in the cohesive strength of the coating film. The film adhesion may be reduced.

  On the other hand, when the content of the binder resin exceeds 34% by mass, the Zn-based metal powder in the coating film, the absolute amount of condensed aluminum phosphate containing Mg is not reduced, and a good rust prevention effect is not exhibited, Corrosion resistance may be reduced. In order to improve both the barrier corrosion prevention and the sacrificial corrosion prevention of zinc and improve the corrosion resistance, the content is more preferably 15% by mass or more and 30% by mass or less with respect to the solid content of the paint.

(1-4) Other additives In the coating composition according to the present invention, a coloring pigment, extender pigment, thickener, fluidity used in a normal coating composition as necessary in addition to the above-described components. It can contain a conditioner, a surface conditioner, a curing catalyst, and the like.

However, coloring pigments and extender pigments may impair corrosion resistance and coating film adhesion due to excessive addition. Therefore, when added, the amount is preferably 10% by mass or less per solid content of the coating composition. As a thickener, in addition to a commonly used thickener, porous silica having an oil absorption of 100 to 1000 ml / 100 g and a specific surface area of 200 to 1000 m ² / g is effective for thickening and improving corrosion resistance. This is preferable.

(1-5) Method for calculating solid content concentration in paint As a method for measuring the content of Zn-based metal powder, Mg-containing condensed aluminum phosphate, and other additives contained in the paint composition as pigment, paint It was obtained by diluting the composition itself with a solvent, extracting the Zn metal powder, Mg-containing condensed aluminum phosphate, and other additives as residues, applying the analysis method and coating composition to the object to be coated, and drying. The method of measuring from a coating film is illustrated.

  As a method of measuring from a coating film obtained by applying a coating composition to an object to be coated and drying, cutting the object to be coated with the above-mentioned coating film, exposing the section of the coating film, Further polish. The cross section thus obtained is observed with an electron microscope to obtain a cross-sectional observation image in the coating film.

  The long side length and the short side length of each of the Zn-based metal powder, Mg-containing condensed aluminum phosphate, and other additives present in the field of the observed image are measured, and the average value and the short side length of these long side lengths are measured. An average value is calculated, and these are averaged to calculate each average particle size.

  Next, the number of Zn-based metal powder, Mg-containing condensed aluminum phosphate, and other additives existing in the field of view is measured, and the Zn-based metal powder, Mg-containing condensed aluminum phosphate, other additives, and binder in the measurement section are measured. Obtain the occupied cross-sectional area of the component.

  Thereafter, the cross section is further polished, and the above-described operations are repeated to obtain the occupied cross section, and the average value of the exclusive cross sectional area of the Zn-based metal powder, Mg-containing condensed aluminum phosphate, other additives and binder components in the five cross-sections and the Zn-based The content is measured from the specific gravity of metal powder, Mg-containing condensed aluminum phosphate, other additives and binder components.

  In addition, the numerical value of content changes a little with measurement methods. The numerical value of the content may vary depending on the measurement principle when the average particle size is calculated using the particle size distribution meter and the above-described method is used, and varies depending on the image processing method in the case of image analysis. To get. However, the content range specified in the present specification takes such fluctuations into consideration, and even if the content obtained by any method is within the range specified in the present specification, Obtaining the desired effect can be realized stably.

(1-6) Manufacturing method of coating composition The manufacturing method of the coating composition which concerns on this invention is the same as that of a general zinc rich coating material, Binder component, Zn type metal powder, Mg containing condensed aluminum phosphate, Although the method of blending other additives etc. with a mixer etc. as needed is illustrated and manufactured, it is not limited to this method.

(1-7) Coating method The method of applying the coating composition to an object to be coated (molding material) such as steel is not particularly limited. For example, an airless coating machine or air spray coating, which is a conventionally known coating method, is used. A coating method using a machine, a brush, a roller or the like is exemplified.

  The coating film thickness of the coating composition depends on the required level of corrosion resistance, but for a coating object on which the surface of the deposition object is not subjected to Zn-based plating, it may be 10 to 50 μm as a dry film thickness. preferable. If the dry film thickness is less than 10 μm, sufficient rust prevention properties may not be obtained. On the other hand, if the dry film thickness exceeds 50 μm, the coating film adhesion is attributed to an increase in the internal stress of the coating film. May be damaged. The dry film thickness is more preferably 15 to 30 μm from the viewpoint of corrosion resistance and adhesion.

  As a method of applying and drying the coating composition, a dry coating film can be obtained by standing in a room temperature environment, but when using a solvent-based coating containing a solvent having a relatively high boiling point. It is preferable to form a dry coating film by baking in an oven or the like. It is also possible to obtain a dry coating film by spraying hot air with an oven and a dryer in order to quickly dry the water-based paint.

The present invention will be described specifically with reference to examples.
(2-1) Preparation of article to be coated The following cold-rolled steel sheet, alloyed hot-dip galvanized steel sheet, and hot-dip galvanized steel sheet are prepared, and 2. aqueous alkaline degreasing agent (FC-301 manufactured by Nihon Parkerizing Co., Ltd.). Each steel plate was immersed in a 5% by mass, 40 ° C. aqueous solution for 2 minutes to degrease the surface, then washed with water and dried to obtain a steel plate for coating.

・ CR: Cold rolled steel sheet (thickness 0.8mm)
GA: Alloyed hot-dip galvanized steel sheet (plate thickness 1.6 mm, 10 mass Fe%, plating adhesion 45 g / m ² )
GI: hot dip galvanized steel sheet (thickness 4.5 mm, plating adhesion 60 g / m ² )

(2-2) Arc welding A GA plate is cut to a size of 70 × 150 mm, Ar + CO ₂ mixed gas is used in the longitudinal direction of the test piece, and an arc is irradiated using YGW12 which is a welding wire for galvanizing, and a bead-on sample is prepared. Produced.

(2-3) Coating composition The Zn-based metal powder and Mg-containing condensed aluminum phosphate shown below were pulverized and mixed so as to have a particle size of 20 μm or less by kneading using beads.

  Among the raw materials shown below, the raw materials described in the column of (A) binder component were blended in the amounts (parts by mass) shown below and mixed with a stirrer. Thereafter, (B) Zn-based metal powder, (C) Mg-containing condensed aluminum phosphate, (D) and other additives shown in Table 1 were blended in the amounts (parts by mass) shown below. Table 1 After adding water so that it might become solid content concentration (Nv) as described in it, it mixed with the stirrer and obtained the coating composition shown in Table 1.

(A) Binder component E1: Epoxy resin emulsion (bisphenol A type epoxy resin Epoxy EA55 (epoxy equivalent 495 g / eq) manufactured by Henkel Japan) and polyamine resin emulsion (modified aliphatic polyamine resin emulsion Fujica FXS manufactured by TOKA) -918-FA) at a solid content mass ratio of 70:30

E2: epoxy resin emulsion (Mitsubishi Chemical Corporation bisphenol A type epoxy resin JER YL980 (epoxy equivalent 180 g / eq)) and polyamine resin emulsion (TOKA company modified aliphatic polyamine resin emulsion FujiSure FXS-918-FA) With a solid content mass ratio of 70:30

E3: Epoxy resin emulsion (Mitsubishi Chemical Corporation bisphenol F type epoxy resin JER YL983U (epoxy equivalent 170 g / eq)) and polyamine resin emulsion (TOKA company modified aliphatic polyamine resin emulsion Fuji Cure FXS-918-FA) With a solid content mass ratio of 70:30

AS: Alkoxysilane (ethyl silicate silicate 45 manufactured by Tama Chemical Industry Co., Ltd.) 0.1N hydrochloric acid, water and isopropyl alcohol are mixed at a mass ratio of 50: 6: 43 and stirred at 40 ° C. for 2 hours. A: Acrylic resin Emulsion resin (Boncoat CE-6400, manufactured by DIC)
-P1: A water-based polyester resin (Toyobo Co., Ltd. Vylonal MD1480 (molecular weight 15000)) and (gamma) -glycidoxypropyl trimethoxysilane are mixed by the solid content mass ratio 90:10 ratio.

P2: Solvent polyester resin (Byron 290 (Molecular weight 22000) manufactured by Toyobo Co., Ltd.) and melamine resin (Symel 325 manufactured by Cymel Co., Ltd.) are mixed at a solid content mass ratio of 70:30. P3: Solvent polyester / melamine clear Paint (Nippon Paint Industrial Coatings Co., Ltd. NK1250SC stain resistant clear paint)

U1: Water-based urethane resin (Daiichi Kogyo Seiyaku Super Flex 620)
U2: Aqueous urethane resin (Superflex 620 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and ammonium zirconium carbonate are mixed at a solid content mass ratio of 90:10.

-U3: Aqueous urethane resin (Superflex 620 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and γ-glycidoxypropyltrimethoxysilane are mixed at a solid mass ratio of 90:10. It was set to 1.4 g / cm ³ .

(B) Zinc-based metal powder. Z1: Zinc-based metal powder having an average particle size of 3 μm obtained by further pulverizing the metal zinc powder of the reagent with a pulverizer and using a sieve and a classifier.

Z2: Zinc-based metal powder having an average particle size of 3 μm obtained by further pulverizing the reagent metal zinc powder with a pulverizer and using a sieve and a classifier, a sufficient amount of silane coupling agent (manufactured by Nimi Shoji Co., Ltd.) Zyla-based metal powder with a surface treatment that was placed in Sila Ace S510), stirred for 1 hr at room temperature, filtered and collected

ZA1: Zinc-based metal powder having an average particle diameter of 3 μm obtained by further pulverizing a mixture of a metal zinc powder of a reagent and metal aluminum at a mass ratio of 95: 5 with a pulverizer and a sieve and a classifier; ZA2: Zinc-based metal powder having an average particle size of 3 μm obtained by further pulverizing a mixture of a metal zinc powder of a reagent and metal aluminum at a mass ratio of 45:55 with a pulverizer and a sieve and a classifier

ZM: Zinc-based metal powder having an average particle diameter of 3 μm obtained by further pulverizing a mixture of a metal zinc powder of a reagent and metal magnesium at a mass ratio of 95: 5 using a pulverizer and a classifier : Zinc-based metal powder having an average particle size of 3 μm obtained by further pulverizing a mixture of metal zinc powder and metal silicon at a mass ratio of 95: 5 with a pulverizer and using a sieve and a classifier

ZAM: Zinc-based powder with an average particle diameter of 3 μm obtained by further pulverizing with a pulverizer a mixture of reagent metal zinc powder and metal aluminum and metal magnesium in a mass ratio of 86: 11: 3 Metal powder

ZAMS1: A mixture of reagent metal zinc powder, metal aluminum, metal magnesium, and metal silicon in a mass ratio of 85.8: 11: 3: 0.2 was further pulverized by a pulverizer, and obtained by a sieve and a classifier. Zinc-based metal powder with an average particle size of 3 μm

ZAMS2: A mixture of reagent metal zinc powder, metal aluminum, metal magnesium, and metal silicon in a mass ratio of 50: 40: 9: 1 was further pulverized by a pulverizer, and the average particle size obtained by a sieve and a classifier 3μm zinc-based metal powder

Specific gravity of the zinc-based metal powder, metallic zinc powder having a specific gravity = 7.14 g / cm ^3, the specific gravity of metallic aluminum 2.7 g / cm ^3, the metallic magnesium specific gravity 1.74 g / cm ^3, the metallic silicon density 2. Based on 33 g / cm ³ , it was calculated by each mixing ratio.

(C) Rust prevention pigment / PAM1: Aluminum trihydrogen phosphate (Mg coating) (Taika condensed aluminum phosphate G105) (average particle size: 1 μm to 3 μm, specific gravity = 2.6)

PAM2: aluminum dihydrogen triphosphate (Mg coating) (Taika condensed aluminum phosphate # 450H) (average particle size 1 μm to 3 μm, specific gravity = 2.2)
PAM3: aluminum dihydrogen phosphate triphosphate (without Mg coating) (Taika condensed aluminum phosphate # 105) (average particle size 1 μm to 3 μm, specific gravity = 3.0) and magnesium hydroxide (commercial product, specific gravity 2.4) Mg-containing aluminum dihydrogen tripolyphosphate mixed at a mass ratio of 95: 5

PAM4: aluminum dihydrogen triphosphate (without Mg coating) (Taika condensed aluminum phosphate # 105) (average particle size 1 μm to 3 μm, specific gravity = 3.0) and magnesium hydroxide (commercial product, specific gravity 2.4) Mg containing trihydrogenaluminum dihydrogen phosphate mixed in a mass ratio of 90:10 PAM5: aluminum dihydrogen tripolyphosphate (without Mg coating) (Taika condensed aluminum phosphate # 105) (average particle size 1 μm to 3 μm, specific gravity = 3.0) and magnesium hydroxide (commercial product, specific gravity 2.4) blended at a mass ratio of 85:15 Mg-containing aluminum dihydrogen triphosphate

PAM6: aluminum trihydrogen phosphate (no Mg coating) (Taika condensed aluminum phosphate # 105) (average particle size 1 μm to 3 μm, specific gravity = 3.0) and magnesium hydroxide (commercial product, specific gravity 2.4) Mg-containing aluminum dihydrogen tripolyphosphate mixed at a mass ratio of 80:20

PAM7: aluminum dihydrogen triphosphate (without Mg coating) (Taika condensed aluminum phosphate # 105) (average particle size 1 μm to 3 μm, specific gravity = 3.0) and magnesium oxide (commercial product, specific gravity 3.7) Mg-containing aluminum dihydrogen tripolyphosphate mixed in a mass ratio of 90:10 4, 5, 6, 7

PA: Aluminum dihydrogen triphosphate (no Mg coating) (Taika condensed aluminum phosphate # 105) (average particle size 1 μm to 3 μm, specific gravity = 3.0)
PM: magnesium phosphate (average particle size 1 μm to 3 μm, specific gravity = 2.1)
SC: Calcium ion exchanged silica (average particle size 1 μm to 3 μm, specific gravity = 2.3)

(D) Other Additives: Si: Silica (Oil absorption amount 100 to 1000 ml / 100 g, specific surface area 200 to 1000 m ² / g, amorphous silica having an average particle diameter of 1 μm to 30 μm, specific gravity = 2.2) (manufactured by Fuji Silysia) Silo mask 02)

(2-4) Preparation of coated sample Using CR plate and GI plate cut to 70 x 150 mm size and GA plate with bead-on applied, air spray coating on the surface and end face, and indoor for 3 days It was made to dry and the coating film of the dry film thickness of Table 2 was obtained. For some paint systems in which the binder resin includes a solvent-based paint, a paint sample was baked in an oven at 150 ° C. for 30 minutes.

(2-5) Evaluation of salt spray corrosion resistance The coating sample using the CR plate and the GI plate as a base material and a GA plate (bead side as an evaluation surface) subjected to bead-on in advance are used as the base material. Using the coated sample, a salt spray test was conducted for 480 hours in accordance with JIS K 5600, rust and blisters were observed, all rust and blisters were corroded, and a determination was made based on the following evaluation criteria. It was determined that three or more of these evaluation criteria were excellent in corrosion resistance.

5: Corrosion area ratio 5% or less 4: Corrosion area ratio 5% or more and 10% or less 3: Corrosion area ratio 10% or more and 20% or less 2: Corrosion area ratio 20% or more 50% or less 1: Corrosion area ratio Over 50%

(2-6) Combined cycle corrosion resistance evaluation Paint sample with CR plate and GI plate as base material and cross-cut in advance, and GA plate with bead-on (bead side as evaluation surface) as base material Using the sample, the corrosion resistance test method of plating based on JIS H8502 ((a) salt spray (35 ° C., 2 hours), (b) dry (60 ° C., 25% RH, 4 hours), (c) wet (50 (Composite cycle corrosion resistance test method) (Sequential ℃, 98% RH, 2 hours) is performed 120 times, rust and blisters are observed, all rust and blisters are corroded, and judgment is made based on the following evaluation criteria. It was. It was determined that three or more of these evaluation criteria were excellent in corrosion resistance.

5: Corrosion area ratio 5% or less 4: Corrosion area ratio 5% or more and 10% or less 3: Corrosion area ratio 10% or more and 20% or less 2: Corrosion area ratio 20% or more 50% or less 1: Corrosion area ratio Over 50%

  Test conditions and test results are summarized in Tables 1 and 2. * In Tables 1 and 2 indicates that the test condition is outside the scope of the present invention, or the test result is unsatisfactory.

  Test Nos. 14 to 19, 22 to 32, and 41 to 81 in Table 2 are examples of the present invention that satisfy all the provisions of the present invention. Reference numerals 1 to 13, 20, 21, and 33 to 40 are comparative examples that do not satisfy the provisions of the present invention.

  From Tables 1 and 2, Test Nos. 14 to 19, 22 to 32, and 41 to 81 are test Nos. Using general coating compositions. It turns out that it is a coating film which has sufficient corrosion resistance even if it is the same film thickness with respect to 1-13, 20, 21, 33-40.

Claims (7)

A coating composition containing a binder resin, a Zn-based metal powder, and condensed aluminum phosphate containing Mg,
The content of the Zn-based metal powder is 65 to 85% by mass with respect to the solid content of the coating composition,
The coating composition whose content of the condensed aluminum phosphate containing Mg is 1 to 15% by mass with respect to the solid content of the coating composition.   The coating composition according to claim 1, wherein the condensed aluminum phosphate containing Mg is a mixture of magnesium hydroxide and aluminum dihydrogen tripolyphosphate.   The coating composition of Claim 2 whose ratio of the mixture of the said magnesium hydroxide and the said aluminum dihydrogen tripolyphosphate is 1: 2-8 by mass ratio.   The coating composition according to claim 1, wherein the condensed aluminum phosphate containing Mg is aluminum dihydrogen tripolyphosphate containing Mg.   The coating composition according to any one of claims 1 to 4, wherein the Zn-based metal powder includes at least one metal powder selected from Al, Mg, and Si.   The coating member by which the coating composition in any one of Claims 1-5 was coat | covered in part or the whole surface of the molding material.   The coating member which has a coating film of the coating composition in any one of Claims 1-5 on the one part or the whole surface of a molding material.