JP2015178538A - Metal-containing compositions for spray coating on metal substrates - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal-containing composition capable of forming a coating film having a consistent film thickness and reduced variation on a metal base material of non-planar shape, a method of spray coating of a metal base material using the metal-containing composition, and a film obtained by the spray coating.SOLUTION: A metal-containing composition for spray coating contains metal particles of an average particle size Dof 0.4-10 μm, a solvent, and a dispersant and has a TI value (thixotropy index) η/ηof 5-30, calculated from measurements of the viscosity at a shear rate of 0.1 [sec] and the viscosity ηat 1,000[sec] measured by a viscosity measurement instrument rheometer. A method of coating a metal base material by using the composition is also provided.

Description

  The present invention relates to a metal-containing composition for spray coating on a metal substrate, a method of spray-coating a metal substrate using the metal-containing composition, and a film obtained by the spray coating.

  Conventionally, metal substrates are excellent in durability, strength, rigidity, and the like, and thus are used in various fields such as furniture, building materials (interior materials, exterior materials), automobiles, and various containers. When using metal substrates, surface treatments such as coating, painting, or laminating are carried out by plating, etc., in addition to the surface treatment such as chromate treatment, in order to improve corrosion resistance, protect the metal surface, or improve the appearance. Yes.

  As a coating method for a non-planar metal substrate, a plating method, a dipping method, or spray coating (Patent Document 1) is known.

JP 2010-137220 A

Electrodeposition of platinum on titanium substrates; Materials Chemistry and Physics; Vol68, 1-3, 15 Feb 2001, p62-65.

  In order to obtain a function such as protection as a surface coating film for a non-planar metal base material, a coating film having a certain thickness or more and less variation is required. However, it is difficult to form a film having a thickness of 10 μm or more with the plating method, and liquid dripping is a problem with the dipping method, and it is difficult to control the film thickness with the plating method and the dipping method.

  Moreover, in order to perform spray coating on a non-planar metal base material, it is difficult to control the film thickness, and it is desired to realize a method capable of satisfactorily coating in a film thickness range of 1 μm to 50 μm.

  In spray coating, generally used pigments have large particles, and it is difficult to achieve a target film thickness. Since the composition using the slurry of nanoparticles disclosed in Patent Document 1 has a large specific surface area of nanoparticles, in order to set the slurry viscosity to be sprayable, it must be extremely low in concentration, It is necessary to fully dilute with a solvent. For this reason, there exists a subject that only a thin coating film of 1 micrometer or less can be formed.

  Accordingly, an object of the present invention is to provide a metal-containing composition capable of forming a coating film having a certain film thickness and little variation even on a non-planar metal substrate, and the metal-containing composition Another object of the present invention is to provide a method of spray-coating a metal substrate using an object, and a film obtained by the spray-coating.

  The present inventors include a metal-containing composition for spray coating on a metal substrate, which contains metal particles having an average particle diameter in a specific range, a solvent, and a dispersant, and has a specific range of TI value (thixotropic index). As a result, it was found that even on a non-planar metal substrate, a coating film with little variation can be formed with a certain film thickness, and the present invention has been completed.

Therefore, the present invention is as follows.
1. Viscosity η _0.1 and 1000 [with a shear rate of 0.1 [sec ⁻¹ ] measured by a viscosity measuring device rheometer, containing metal particles having an average particle diameter D ₅₀ of 0.4 to 10 μm, a solvent, and a dispersant. metal for spray coating on a metal substrate, characterized in that the TI value (thixotropic index) η _0.1 / η ₁₀₀₀ calculated from the measured value of the viscosity η ₁₀₀₀ at sec ⁻¹ ] is 5 to 30 Containing composition.
2. 2. The metal-containing composition according to item 1, wherein the dispersant is a higher fatty acid or a salt thereof, or a surfactant.
3. 3. The metal-containing composition according to item 1 or 2, further containing a resin.
4). 4. The metal-containing composition according to any one of items 1 to 3, wherein the solid content is 45% by mass to 75% by mass.
5. In the preceding items 1 to 4, wherein the metal particles are one or more selected from the group consisting of gold, silver, platinum, palladium, ruthenium, nickel, copper, tin, indium, zinc, chromium, iron and manganese. The metal-containing composition according to any one of the above.
6). 1 to 5 above, wherein the solvent is one or more selected from the group consisting of aromatic hydrocarbons, glycol ethers, esterified products of glycol ethers, alcohols, ketones, and monoterpene alcohols. The metal-containing composition according to any one of the above.
7). 7. The metal-containing composition according to any one of items 1 to 6, wherein a contact angle with SUS304 polished to a surface roughness of 0.4 μm is 20 ° or less.
8). 8. The metal-containing composition according to any one of items 1 to 7, wherein the metal particles are monodisperse.
9. 9. The metal-containing composition according to any one of items 1 to 8, wherein a maximum particle size D ₁₀₀ / average particle size D ₅₀ is 4 or less in the particle size distribution of the metal particles.
10. The metal-containing composition of any one of Claims 1-9 is spray-coated on a metal base material, The method of coating a metal base material including the process of forming a coating film.
11. 11. The method according to 10 above, wherein the spray coating is performed using a spray nozzle having a two-fluid injection valve for causing a jet of liquid to collide with a swirling airflow formed by jetting and colliding compressed air.
12 12. The method according to item 10 or 11, wherein the metal substrate has a non-planar shape.
13. 13. The method according to any one of items 10 to 12, further comprising a step of baking the coating film.
14 14. A metal thin film coated on a metal substrate by the method according to any one of 10 to 13 above.
15. A metal thin film having a thickness of 1 to 50 μm coated on a non-planar metal substrate.
16. 16. The metal thin film according to 15 above, wherein the variation in thickness is within ± 6% from the average value.

According to the metal-containing composition of the present invention, by the average particle diameter D ₅₀ selects the metal particles 0.4～10Myuemu, it is possible to adjust the slurry properties spraying capable, metal with a constant thickness Spray coating on the substrate is possible.

  In general, if the droplets of the metal-containing composition to be sprayed are small, the weight of the metal-containing composition is light and the surface tension becomes very large, so it tends to be spherical, difficult to apply uniformly, and spray coating is difficult. It is. However, according to the metal-containing composition of the present invention, the surface tension of the slurry can be lowered by containing the solvent and the dispersant, and the contact angle with the metal substrate can be reduced to a certain angle or less. It is possible to coat without becoming spherical on the substrate.

Furthermore, in order to increase the film thickness of the coating film, it is necessary to increase the coating amount on the metal substrate, but when the coating amount is increased, there is a problem that the coated metal-containing composition tends to sag. However, according to the metal-containing composition of the present invention, the viscosity eta ₁₀₀₀ slurry viscosity in the viscosity eta _0.1 and 1000 ^{[sec -1]} in shear rate 0.1 ^{[sec -1]} by viscosity measuring device rheometer Since the calculated TI value (thixotropy index) η _0.1 / η ₁₀₀₀ is 5 to 30, the metal-containing composition applied to the metal substrate does not drip even when thickly applied, so the coating amount is increased. There is an advantage that the film thickness of the coating film can be increased.

  Below, the form for implementing this invention is demonstrated.

  The metal particles contained in the metal-containing composition of the present invention are, for example, 1 selected from the group consisting of gold, silver, platinum, palladium, ruthenium, nickel, copper, tin, indium, zinc, chromium, iron and manganese. It is preferable to contain seeds or two or more kinds of metal particles.

The metal particles have an average particle diameter (diameter) D ₅₀ of 0.4 to 10 μm, preferably 0.5 to 6 μm, and more preferably 0.6 to 3 μm. When the average particle diameter (diameter) D ₅₀ exceeds 10 μm, a thin coating film cannot be obtained, and the smoothness of the film is lost. If the average particle diameter (diameter) D ₅₀ is less than 0.4 μm, agglomeration of slurry tends to occur, It leads to outbreak.

The average particle diameter D ₅₀ of the metal particles was measured using a laser diffraction scattering type particle size distribution measuring apparatus Microtrac MT3000 manufactured by Nikkiso Co., Ltd..

  In order to form a coating film efficiently, it is preferable to select a powder having an average particle size of 1/3 or less of the target film thickness.

As the metal particles, it is preferable to use monodisperse particles having a uniform particle diameter in order to control the variation in film thickness. In the present invention, “monodispersity” means that the maximum particle diameter D ₁₀₀ / average particle diameter D ₅₀ is 4 or less. The maximum particle diameter D ₁₀₀ / average particle diameter D ₅₀ of the metal particles is preferably 4 or less, more preferably 3 or less, and still more preferably 2 or less. When the maximum particle size D ₁₀₀ / average particle size D _{50 of the} metal particles is 4 or less, smoothness of the film can be obtained.

Further, from the viewpoint of monodisperse metal particles, the total frequency of particles having a particle diameter larger than twice the average particle diameter D ₅₀ is preferably 12% or less, and 7% or less. More preferably, it is 5% or less.

  Content of the metal particle in a metal containing composition becomes like this. Preferably it is 45-75 mass%, More preferably, it is 50-70 mass%, More preferably, it is 55-60 mass%. If it is 75% by mass or less, the increase in slurry viscosity can be suppressed, and the situation where the spray nozzle is clogged can be avoided, and if it is 45% by mass or more, the decrease in the TI value of the composition can be suppressed. Can be prevented.

  For monodispersed metal particles, a colloidal solution containing a predetermined amount of ultrafine metal particles that serve as nuclei is prepared in advance, and a reducing agent and a metal salt solution are added to this solution one after another, so that metal is deposited on the surface of the fine particles. (For example, JP-A-9-20903).

  Specifically, for example, assuming that the content of core particles at the time of preparation of particles having a particle diameter of 0.4 μm is 1, the content of core particles required for preparation of particles having a particle diameter of 0.2 μm may be eight. In the above gold precipitation growth process, it is considered that the precipitation growth reaction proceeds in the same direction for the individual core particles under the same conditions, so that it is possible to obtain a metal fine powder composed of spherical monodisperse particles with a uniform particle size. Become.

  The metal-containing composition of the present invention can lower the contact angle between the metal substrate and the slurry droplets by containing a solvent. Thereby, the variation in film thickness can be controlled, and the contact angle with the SUS304 plate polished to a surface roughness of 0.4 μm is preferably 20 ° or less. Moreover, drying property can be adjusted by containing a solvent.

  As the solvent, commonly used organic solvents are preferably used. For example, ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol , Glycol ethers such as butyl carbitol, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monoethyl ether and triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, cellosolve acetate, diethylene glycol monomethyl ether Acetate, diethylene glycol monoethyl ether acetate, propylene glycol Esters such as alcohol monomethyl ether acetate and esterified products of the above glycol ethers; alcohols such as ethanol, propanol, ethylene glycol and propylene glycol; monoterpene alcohols such as pine oil, terpineol and dihydroterpineol; it can.

  Content of the solvent in a metal containing composition becomes like this. Preferably it is 23-55 mass%, More preferably, it is 30-50 mass%, More preferably, it is 40-45 mass%. If it is 55% by mass or less, the solid content concentration of the slurry is prevented from lowering, and the film thickness obtained by one spray coating does not become thin, so the number of laminations required until the target film thickness target film thickness does not increase , Spray painting does not take a long time. If it is 23 mass% or more, the increase in slurry viscosity can be prevented and the situation where the spray nozzle is clogged can be avoided.

  The metal-containing composition of the present invention can also reduce the contact angle between the metal substrate and the slurry droplets by containing a dispersant. Thereby, the variation in film thickness can be controlled, and the contact angle with the SUS304 plate polished to a surface roughness of 0.4 μm is preferably 20 ° or less.

  Examples of the dispersant include higher fatty acids or salts thereof, and surfactants.

  The higher fatty acid or a salt thereof is preferably a salt of a higher fatty acid having 12 to 60 carbon atoms, more preferably an alkali metal salt, alkaline earth metal salt or amine salt of a higher fatty acid having 15 to 40 carbon atoms.

  Furthermore, the salt of higher fatty acid may contain a higher fatty acid and / or an ester of higher fatty acid in addition to the salt of higher fatty acid. The alcohol residue constituting the ester preferably has 2 to 30 carbon atoms, and particularly preferably 6 to 20 carbon atoms. Residues can be linear or branched. A mixture of different carbon numbers may be used.

  Specific examples of the alcohol residue include residues of higher alcohols such as cetyl alcohol, stearyl alcohol, and oleyl alcohol.

  A salt of a higher fatty acid can be obtained by neutralizing the higher fatty acid and / or saponifying the higher fatty acid ester. In this case, it may be a partially neutralized product or a partially saponified product in which a higher fatty acid or a higher fatty acid ester not neutralized or saponified coexists.

  Examples of the surfactant include known nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Among these, a nonionic surfactant is preferable and a nonionic fluorine-based surfactant is more preferable from the viewpoint of improving dispersion of metal powder and wettability to a metal substrate. Examples of the fluorine-based surfactant include Surflon S-611, Surflon S-651 and Surflon S-386 manufactured by AGC Seimi Chemical Co., and Megafac F559 and F567 manufactured by DIC.

  The content of the dispersant or the surfactant in the metal-containing composition is preferably 0.1 to 1.5% by mass, more preferably 0.8 to 1.4, and still more preferably 0.9. ~ 1.2. This is because the slurry viscosity can be controlled when the content is 1.5% by mass or less, and the situation where spray coating cannot be performed without being wetted by the base material can be avoided when the content is 0.1% by mass or more.

  The metal-containing composition of the present invention can improve wettability with a metal substrate by containing a solvent and a dispersant. Moreover, according to the kind of metal base material, these content rates can be changed suitably.

Metal-containing composition of the present invention, TI value calculated from viscosity eta ₁₀₀₀ in viscosity eta _0.1 and 1000 ^{[sec -1]} in a shear rate of 0.1 by the viscosity measuring apparatus rheometer ^{[sec -1]} (thixotropy Index) [eta] _0.1 / [eta] ₁₀₀₀ is 5-30, preferably 15-28, more preferably 20-25. When the TI value is 5 to 30, a coating film with little variation can be formed on a non-planar metal substrate, preferably in the range of 1 to 50 μm. In the present invention, the TI value is a value measured at a temperature of 25 ° C. according to JIS K5600-2-3 (1999) using a viscosity measuring device rheometer HAAKE RheoStress 3000 as a rotary viscometer. .

  Examples of the method of increasing the TI value include a method of adding a resin having thixotropy to the metal composition, a method of increasing the solid content of the slurry, and a method of using a thickener. Examples of the thickener include BYK-410, BYK415, and BYK430 manufactured by BYK Chemie. If the TI value is too high, the leveling property of the composition is lowered, and the sprayed droplets try to keep a spherical shape, so that wetting and spreading do not occur.

  As said resin, the resin currently used for coating materials can be used. Specific examples thereof include, for example, an acrylic resin, a polyester resin, an alkyd resin, an ethyl cellulose resin, a fiber-based resin, a polyolefin resin, a chlorinated polyolefin resin, a fluororesin, a silicon resin, etc., alone or in combination of two or more. Non-crosslinked lacquer type is exemplified. Moreover, for example, a cross-linking curable resin combined with the above-mentioned resin and a cross-linking agent such as an amino resin, a polyisocyanate compound, a blocked polyisocyanate compound, and an epoxy compound can be used. Of the above resins, thixotropic ethyl cellulose resin and polyvinyl butyral resin are preferable.

  The resin may be a functional material. Examples of the resin used as the functional material include a thermosetting resin and a radiation curable resin using ultraviolet rays or an electron beam. Further, a thermosetting resin and a radiation curable resin can be used in combination with a thermosetting resin and a radiation curable resin.

  The resin content in the metal-containing composition is preferably 0.5 to 4% by mass, more preferably 0.6 to 3.5% by mass, and still more preferably 1 to 2% by mass. If it is 4% by mass or less, an increase in slurry viscosity can be suppressed and a situation where the spray nozzle is clogged can be avoided, and if it is 0.5% by mass or more, a decrease in the thixotropy of the slurry can be prevented and the coating film drips. The situation can be avoided.

  In the metal-containing composition of the present invention, the solid content of the slurry is preferably 45% by mass or more, more preferably 50% by mass or more, and further preferably 55% by mass or more. Moreover, it is preferable that it is 75 mass% or less normally.

  Slurry is a general term for liquids in which solid particles are suspended in a liquid. If the solid content is 45% by mass or more, a surface coating film with little variation is formed on a non-planar metal base material within a thickness range of 1 to 50 μm by having an appropriate TI value. Because it can.

  In addition to the above components, the metal-containing composition of the present invention may contain various additive components, for example, an antifoaming agent, various additives, and extender pigments as necessary.

  As an antifoamer, a well-known thing can be used, For example, a silicone type, a hydrocarbon type, an acrylic type etc. are mentioned.

  Examples of various additives include dispersants such as coupling agents such as silane, titanate and alumina, boron trifluoride-amine complex, dicyandiamide (DICY) and its derivatives, organic acid hydrazide, diaminomaleonitrile (DAMN). ) And derivatives thereof, guanamine and derivatives thereof, melamine and derivatives thereof, latent curing agents such as amine imide (AI) and polyamine, metal salts of acetylacetone such as acetylacetonate Zn and acetylacetonate Cr, enamine, tin octylate, Examples include quaternary sulfonium salts, triphenylphosphine, imidazole, imidazolium salts, and thermosetting accelerators such as triethanolamine borate.

  The extender pigment is for increasing the physical strength of the coating film, and examples thereof include silica, barium sulfate, alumina, aluminum hydroxide, talc and mica.

  The above ingredients and other ingredients as necessary are blended after mixing at a predetermined ratio, and if necessary, kneaded or mixed by a kneading means such as a three roll, ball mill or sand mill, or a stirring means such as a super mixer or planetary mixer. Thus, the metal-containing composition of the present invention is obtained.

  The metal-containing composition of the present invention preferably has a contact angle with SUS304 of 20 ° or less, more preferably 15 ° or less, and even more preferably 10 ° or less. This is because the liquid of the metal-containing composition wets and spreads on the surface of the covering when the angle is 20 ° or less. Moreover, it is usually 25 ° or more. The contact angle between the metal-containing composition and SUS304 can be measured, for example, by a droplet method using a contact angle meter DMs-400 (Kyowa Interface Science Co., Ltd.).

  Examples of the method for setting the contact angle between the metal-containing composition and SUS304 to 20 ° or less include, for example, a surface plasma / UV treatment of a substrate for adjusting the content of a low surface tension solvent and dispersant, and a surfactant. Surface blasting can be mentioned.

  Examples of the spray coating means include an electrostatic spray spray device, an air spray spray device, and an airless spray spray device.

  As a spray nozzle used for spray coating, a system having a two-fluid injection valve is preferable. In particular, a method of ejecting the coating material to the center of the swirling airflow of compressed air swirled by the air assist method is preferable. The spraying conditions can be set as appropriate.

  The above-mentioned spray coating method is preferable because it allows the droplets of the coating material to be atomized, and enables the formation of a 1-50 μm coating film on the coated body and a uniform coating film. In addition, the coating film can be formed with a uniform film thickness on the shadowed portion, the uneven portion, or the end portion of the non-planar metal base material due to the wraparound effect of the airflow.

  By spray coating using the metal-containing composition of the present invention, the thickness of the metal thin film formed on the metal substrate is preferably 1 to 50 μm, more preferably 5 to 30 μm, and 8 More preferably, it is ˜25 μm. The film thickness was measured using a fluorescent X-ray film thickness meter SFT-110 manufactured by SII Nanotech.

Further, when the thickness of the metal thin film is measured at 10 points and the arithmetic average value (average value) is calculated, the thickness variation represented by the following formula is preferably within ± 6% from the average value.
Thickness variation (%) = standard deviation of thickness measurement value / average thickness value × 100%

  Moreover, you may bake the coating film formed on the metal substrate using the metal containing composition of this invention. By baking the coating film, the added resin can be dissolved and lost. The firing temperature is often about 2/3 of the melting point of the metal normally contained. For example, in the case of nickel or platinum, the firing temperature is preferably 800 ° C. or higher, more preferably 800 ° C. to 1400 ° C., and still more preferably 1000 ° C. to 1200 ° C. A dense metal film can be obtained.

  Moreover, it is preferable that baking time is 30 minutes or more normally, More preferably, it is 1 to 48 hours, More preferably, it is 1 to 12 hours.

  Examples of the metal substrate on which the metal-containing composition of the present invention is spray-coated include ferrous metals such as iron and stainless steel, and non-ferrous metals such as aluminum, magnesium, zinc, and alloys thereof. It does not specifically limit as this iron-type base material, For example, a cold-rolled steel plate, a hot-rolled steel plate, a stainless steel plate, etc. can be mentioned.

  The non-ferrous metal substrate is not particularly limited, and examples thereof include an aluminum steel plate, a zinc steel plate, a magnesium alloy, an aluminum-zinc alloy, a zinc-nickel plated steel plate, a zinc-chromium plated steel plate, and a zinc-magnesium plated steel plate. it can. Examples of the object to be coated that is a metal substrate include electrical appliances, automobile parts (for example, aluminum wheels), building materials, structures (for example, turbine blades), and office equipment. The metal substrate may have a planar shape or a non-planar shape.

  EXAMPLES Hereinafter, although an Example and a comparative example further demonstrate this invention, this invention is not restrict | limited to the following example.

In the following Examples and Comparative Examples, the average particle diameter D ₅₀ of the metal particles, using a laser diffraction scattering type particle size distribution measuring apparatus Microtrac MT3000 manufactured by Nikkiso Co., Ltd. was measured. The TI value of the metal-containing composition was measured using a rheometer HAAKE RheoStress 3000 manufactured by Thermo Fisher Scientific. The contact angle between the metal-containing composition and the metal substrate is measured by a tangent method (refer to http://www.sanyo-kruss.com/qa/products01.html) from a photograph taken from the side of the droplet. did.

[Example 1]
First, using a ball mill as a primary blend, the average particle diameter D ₅₀ is 0.6 μm, and D ₁₀₀ / D ₅₀ is 2.1 (D ₅₀ = 0.6, D ₁₀₀ = 1.3). 100 g of certain nickel powder was dispersed in 30.0% by mass of alkylbenzene, 12.0% by mass of butyl diglycol acetate, and 18.0% by mass of terpineol as a solvent. Further, 1.0% by mass of isostearic acid, which is a higher fatty acid, was added as a surfactant as a dispersant, and 5 times the amount of 3φ mm alumina beads was used to disperse the primary compound over 20 hours.

Furthermore, as a secondary compound, as a resin (also referred to as a binder), 1.5% by mass of ethyl cellulose (Ethocel STD4, manufactured by The Dow Chemical Company) as an external coating with respect to nickel powder, dioctyl phthalate (plasticizer) Hereinafter, 0.3% by mass of DOP was added to the primary blend, and the ball mill was further dispersed for 15 hours. The obtained slurry was measured with a viscosity measuring device rheometer HAAKE RheoStress 3000. The viscosity value η _{0.1 at a} shear rate of 0.1 [sec ⁻¹ ] is 3840 [mPa · s], the viscosity value η _{1000 at} 1000 [sec ⁻¹ ] is 150 [mPa · s], and the TI value (η _0.1 / η ₁₀₀₀ ) was 26. The contact angle between the metal-containing composition and the metal substrate was 20 °.
[Example 2]
First, using a ball mill as a primary blend, the average particle diameter D ₅₀ is 0.7 μm, and D ₁₀₀ / D ₅₀ is 2.5 (D ₅₀ = 0.7, D ₁₀₀ = 1.8). 100 g of a certain platinum powder was dispersed as a solvent in a mixed solvent of 30.0% by mass of alkylbenzene, 12.0% by mass of butyl diglycol acetate, 18.0% by mass of terpineol and 20.0% by mass of ethanol. Furthermore, 1.0% by mass of a surfactant as a dispersant was added, and 5 times the amount of 3φ mm alumina beads was used, and the primary compound was dispersed over 20 hours.

In addition, as a secondary compound, ethyl cellulose (Ethocel STD4, manufactured by The Dow Chemical Company) 1.5% by mass and DOP 0.3% by mass as a plasticizer are primary for resin as an external coating on platinum powder. It was added to the blend and further a ball mill was dispersed over 15 hours. The obtained slurry was measured with a viscosity measuring device rheometer HAAKE RheoStress 3000. The viscosity value η _{0.1 at a} shear rate of 0.1 [sec ⁻¹ ] is 1010 [mPa · s], the viscosity value η _{1000 at} 1000 [sec ⁻¹ ] is 190 [mPa · s], and the TI value (η _0.1 / η ₁₀₀₀ ) was 5. The contact angle between the metal-containing composition and the metal substrate was 10 °.

  In Examples 3 to 10 and Comparative Examples 1 to 7, the slurry was dispersed in the same process as in Example 1 except that the metal particles and the blending ratio were different, and measurement was performed. Tables 1 and 2 show the type, blending ratio, solid content, TI value, and contact angle between the metal-containing composition and the metal substrate.

  Using the metal-containing compositions prepared in Examples 1 to 10 and Comparative Examples 1 to 7, coating was performed under the following conditions. Moreover, the obtained coating film was evaluated on condition of the following. The results are shown in Tables 1 and 2. In the spray coating item column of Table 1 and Table 2, “-” indicates that a coating film could not be formed.

[Coating conditions]
The metal-containing compositions prepared in Examples 1 to 10 and Comparative Examples 1 to 7 were each spray-coated on a propeller having three general-purpose stirring blades made of SUS304 using a spray spray device. The spraying conditions were as follows: a thin film coating small apparatus equipped with a Nordson swirl II nozzle, syringe pressure 9.6 kpa, needle opening 0.12 mm, nozzle distance 90 mm, gun speed X33 mm / s, gun speed Y5 mm / s, OFFSET1 0.5 mm, pulse time 50/50 msec, pulse air (Air) 0.15 Mpa, pulse air (swirl flow) 0.1 Mpa, and the next lamination waiting time 10 sec. After the spray coating was completed, the sample was put into a constant temperature bath at 150 ° C. and dried for 15 minutes.

  The laminated film thickness of the coating film obtained by the coating was measured with a fluorescent X-ray film thickness meter.

[Evaluation of spray painting]
(1) Film thickness The film thickness of the coating film obtained by the coating was measured with a fluorescent X-ray film thickness meter.
(2) Film thickness variation The film thickness of the coating film was measured at 20 points, the average value was calculated, and the thickness variation was determined by the following formula.
Thickness variation (%) = standard deviation of measured thickness value / average thickness value × 100%

As shown in Table 1 and Table 2, in Examples 1 to 10, by the inclusion of metal particles having an average particle diameter D ₅₀ is 0.4~10μm the metal-containing composition, the slurry properties spray sprayable It was possible to adjust to a metal substrate with a constant film thickness.

  Moreover, in Examples 1-10, by containing a solvent and a dispersing agent in a metal containing composition, the surface tension of a slurry can be lowered | hung and the contact angle of a slurry and a metal base material shall be 20 degrees or less. As a result, the slurry droplets spread on the metal substrate without maintaining a spherical shape, thereby enabling coating.

In Examples 1-10, it TI value slurry viscosity is calculated by viscosity measurements at shear rate 0.1 ^{[sec -1]} and 1000 ^{[sec -1]} by rheometer is 5-30 As a result, the coated metal-containing composition did not sag even after thick coating, and a coating film with sufficient film thickness was obtained.

  On the other hand, it laminated | stacked 10 times using the metal containing composition of Comparative Examples 1-2. The coating conditions are the same as in Example 1 except for the number of coatings. In Comparative Examples 1 and 2, the TI value exceeded 30 and the contact angle between the slurry and the metal substrate was greater than 20 °. For this reason, the slurry droplets maintained a spherical shape on the metal substrate and could not be coated.

  The metal-containing composition of Comparative Example 3 was laminated 50 times. The coating conditions are the same as in Example 1 except for the number of coatings. The laminated film thickness and the film thickness variation were measured in the same manner as in Example 1. As a result of the TI value being less than 5, there was dripping of the coating liquid, and the obtained film thickness variation was as large as 26%.

  The metal-containing composition of Comparative Example 4 was laminated 50 times. The coating conditions are the same as in Example 1 except for the number of coatings. The laminated film thickness and the film thickness variation were measured in the same manner as in Example 1. As a result of the TI value being less than 5, there was dripping of the coating liquid, and the obtained film thickness variation was as large as 37%.

  The metal-containing composition of Comparative Example 5 was laminated 50 times. The coating conditions are the same as in Example 1 except for the number of coatings. The laminated film thickness and the film thickness variation were measured in the same manner as in Example 1. Since the average particle size was less than 0.4 μm and fine powder existed, the coating film had protrusions and voids, and the obtained film thickness variation was as large as 52%.

  The metal-containing composition of Comparative Example 6 was laminated 50 times. The coating conditions are the same as in Example 1 except for the number of coatings. The laminated film thickness and the film thickness variation were measured in the same manner as in Example 1. There was dripping of the coating liquid, and the variation in film thickness was as large as 25%. This is probably because the solid content was as low as 43% by mass, the viscosity of the composition was lowered, and the TI value was also less than 5.

  When the metal-containing composition of Comparative Example 7 was used, the coating conditions were the same as in Example 1. As a result, the viscosity of the composition was too high, resulting in nozzle clogging, and spray coating was not possible. This is presumably because the solid content of the metal component was as high as 79% by mass and the viscosity of the composition was increased.

  The same results as in Example 1 were obtained even when the isostearic acid of the dispersion was changed to stearic acid, or isostearic alcohol, isopalmityl alcohol, or a surfactant having a perfluoroalkyl group.

  The metal-containing composition of the present invention can be used for spray coating on a metal substrate, and particularly as a surface coating for a non-planar metal substrate. Furthermore, it can be used for spray coating in the fields of turbines such as ships, airplanes, and garbage incinerators at high temperatures (1000 ° C. or higher), and in the electronics field and general coating fields at low temperatures.

Claims (16)

Viscosity η _0.1 and 1000 [with a shear rate of 0.1 [sec ⁻¹ ] measured by a viscosity measuring device rheometer, containing metal particles having an average particle diameter D ₅₀ of 0.4 to 10 μm, a solvent, and a dispersant. metal for spray coating on a metal substrate, characterized in that the TI value (thixotropic index) η _0.1 / η ₁₀₀₀ calculated from the measured value of the viscosity η ₁₀₀₀ at sec ⁻¹ ] is 5 to 30 Containing composition.   The metal-containing composition according to claim 1, wherein the dispersant is a higher fatty acid or a salt thereof, or a surfactant.   The metal-containing composition according to claim 1 or 2, further comprising a resin.   Solid content rate is 45 mass%-75 mass%, The metal containing composition of any one of Claims 1-3.   The metal particles are one or more selected from the group consisting of gold, silver, platinum, palladium, ruthenium, nickel, copper, tin, indium, zinc, chromium, iron and manganese. The metal-containing composition according to any one of the above.   The solvent is one or more selected from the group consisting of aromatic hydrocarbons, glycol ethers, esterified products of glycol ethers, alcohols, ketones and monoterpene alcohols. 6. The metal-containing composition according to any one of 5 above.   The metal-containing composition according to claim 1, wherein a contact angle with SUS304 polished to a surface roughness of 0.4 μm is 20 ° or less.   The metal-containing composition according to claim 1, wherein the metal particles are monodisperse. 9. The metal-containing composition according to claim 1, wherein in the particle size distribution of the metal particles, the maximum particle size D ₁₀₀ / average particle size D ₅₀ is 4 or less.   The metal-containing composition of any one of Claims 1-9 is spray-coated on a metal base material, The method of coating a metal base material including the process of forming a coating film.   The method according to claim 10, wherein the spray coating is performed using a spray nozzle having a two-fluid injection valve that causes a jet of liquid to collide with a swirling airflow formed by jetting and colliding compressed air.   The method according to claim 10 or 11, wherein the metal substrate has a non-planar shape.   The method of any one of Claims 10-12 further including the process of baking the said coating film.   A metal thin film coated on a metal substrate by the method according to claim 10.   A metal thin film having a thickness of 1 to 50 μm coated on a non-planar metal substrate.   The metal thin film according to claim 15, wherein the variation in thickness is within ± 6% from the average value.