JP6611110B1 - Film formation method - Google Patents

Abstract

Provided are a film forming method capable of achieving both anticorrosion and antifouling properties, a metal part on which a film is formed, and an outdoor unit of an air conditioner. An electrode and a metal substrate connected to the electrode are immersed in the paint, and a voltage is applied to form an electrodeposition resin film on the metal substrate, and water or an aqueous solution is attached to the surface of the electrodeposition resin film. A hydrophilicity imparting step for imparting hydrophilicity, a silica particle adhesion step for adhering silica particles to the electrodeposited resin film imparted with hydrophilicity, and embedding and embedding at least a part of the silica particles in the surface layer of the electrodeposited resin film. The silica particles are bonded to the silica particles to form a cured resin film by curing the electrodeposited resin film while exposing the silica particles outside the surface of the electrodeposited resin film, and to form a silica particle layer on the surface of the cured resin film A layer forming step.

Description

  The present invention relates to a film forming method for imparting antifouling property to an anticorrosion film of metal parts.

Electrodeposition coating, which is one of the film forming methods for imparting anticorrosion properties to metal parts, is, for example, a metal that is an object to be coated in a coating for electrodeposition coating (hereinafter referred to as paint) dispersed or dissolved in water. A metal base material (hereinafter referred to as a base material) of a part is immersed, and a resin film is formed on the base material by applying a voltage between the base material and the electrode to cause a current to flow. Electrodeposition coating is widely used as an anticorrosion treatment for metal parts having complex shapes because it can coat the details of the substrate.
Thus, while corrosion resistance can be imparted to metal parts by electrodeposition coating, since the resin film after baking and drying has hydrophobicity, there is a problem that hydrophobic dirt such as oil tends to adhere.
Therefore, for example, a technique for imparting hydrophilicity to the surface of the resin film by applying a resin containing silica particles to a substrate that has been electrodeposited and baked and dried to prevent hydrophobic contamination (see, for example, Patent Document 1) ), A technique for forming a hard coat layer on a substrate using a hard coat film in which silica particles are embedded on the surface of a resin (for example, see Patent Document 2) has been studied.

JP-A-2005-36287 JP 2010-241919

However, in Patent Document 1, although the initial hydrophilicity can be obtained by the silica particles on the baked and dried resin film, only the adhering silica particles gradually peel off, so that the hydrophilicity can be maintained for a long time. difficult.
In Patent Document 2, since silica particles are embedded in the resin of the hard coat layer, sufficient hydrophilicity cannot be obtained.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a film forming method that achieves both anticorrosion and antifouling properties. Moreover, it aims at providing the metal component which has anticorrosion property and antifouling property. Furthermore, it aims at providing the outdoor unit of the air conditioner which has antifouling property for a long term and can improve air-conditioning performance.

  The film forming method according to the present invention includes an electrodeposition step of immersing an electrode and a metal substrate connected to the electrode in a paint, and applying a voltage to form an electrodeposited resin film on the metal substrate; A hydrophilicity imparting step in which water or an aqueous solution is attached to the surface of the electrodeposited resin film to impart hydrophilicity; a silica particle adhering step in which silica particles are adhered to the electrodeposited resin film imparted with hydrophilicity; and at least the silica particles A portion of the electrodeposited resin film is embedded in the surface, bonded to the embedded silica particles, and the electrodeposited resin film is cured while exposing the silica particles to the outside of the surface of the electrodeposited resin film. And a silica particle layer forming step of forming a silica particle layer on the surface layer of the cured resin film.

  In addition, a metal part formed with a film according to the present invention includes a metal substrate, a cured resin film formed on the metal substrate, and an embedded surface in which at least a part of silica particles is embedded in the surface layer of the cured resin film. A silica particle layer is provided that includes a recessed portion and an exposed portion in which silica particles bonded to the embedded portion are exposed outside the surface layer of the cured resin film.

  Moreover, the outdoor unit of the air conditioner in which the film | membrane concerning this invention was formed exchanges the heat | fever of the gas taken in from the intake port provided in the housing | casing, and at least any one of a fin and a copper pipe applies to this invention A heat exchanger that is a metal part having a film formed thereon, a fan that circulates the gas heat-exchanged by the heat exchanger, and a fan motor that drives the fan.

  According to the present invention, in the base material of the metal part, the cured resin film and the embedded portion in which at least a part of the silica particles are embedded in the surface layer of the cured resin film, and the silica particles in the embedded portion are bonded and exposed. Since the silica particle layer composed of the exposed portion thus formed can be formed, the metal parts can be provided with anticorrosion and long-term stable antifouling properties.

It is process drawing of the film | membrane formation method concerning Embodiment 1 of this invention. It is a schematic block diagram of the coating tank in the electrodeposition process concerning Embodiment 1 of this invention. It is a schematic block diagram of the silica particle tank in the silica particle adhesion process concerning Embodiment 1 of this invention. It is a schematic diagram of the silica particle layer and cured resin film concerning Embodiment 1 of this invention. It is a schematic block diagram of the outdoor unit of the air conditioner concerning Embodiment 2 of this invention. It is a schematic diagram of the heat exchanger of the air conditioner concerning Embodiment 2 of this invention.

Embodiment 1 FIG.
In order to impart antifouling properties to metal parts, the surface of the base material is degreased and chemically treated, and after electrodeposition coating, a cured resin film is formed by baking and drying. In the attaching method, the silica particles gradually peel off.
Therefore, the inventor considered that it is necessary to expose silica particles for preventing hydrophobic stains on the surface layer of the cured resin film and to embed a part thereof in the cured resin film. As a result of intensive studies, it was found that a strong silica particle layer can be formed by the following method. This will be described below.

FIG. 1 is a process diagram of a film forming method according to Embodiment 1 of the present invention, in which a degreasing process S1, a chemical conversion process S2, an electrodeposition process S3, a hydrophilicity imparting process S4, a silica particle attaching process S5, and a silica particle A layer forming step S6 is included.
First, the degreasing process S1 which removes the oil component of the base material 4 surface of metal parts is performed. And the chemical conversion process S2 which forms a phosphate membrane | film | coat, for example on the degreased base material 4 and makes it the base of coating is performed. These treatments are for improving the lubricity and corrosion resistance of the base material 4 and improving the adhesion between the base material 4 and the electrodeposition resin film 3 in the electrodeposition step S3 described later.

  In the degreasing step S1, it is immersed in a degreasing agent, for example, a neutral degreasing agent MGC13-B for aluminum manufactured by Murata, for 2 minutes to 8 minutes, preferably 1 minute to 10 minutes. Chuo Kagaku BF500S, BF4400, ES3000, Dipsol NZ-77, P-0731, EZ-988, etc. may be used. It is preferable to perform washing with water for about 1 minute to 10 minutes after the degreasing step S1.

  In chemical conversion process S2, it immerses in a chemical conversion treatment agent, for example, MP-440 by Murata, for 1 minute or more and 5 minutes or less. Chemicoat No. ZR series, No. 425, no. 502K, No. 600CS, No. 559, no. 5700 or the like may be used. It is preferable to perform water washing for about 1 to 10 minutes after the chemical conversion step S2.

Next, as shown in FIG. 2, the electrodeposition resin film 3 is formed by an electrodeposition step S3 using, for example, an epoxy resin, a urethane resin or the like as the binder resin of the paint 5.
The paint 5 in the paint tank 6 contains water, a binder resin dissolved or dispersed in water, a neutralizing acid, ethanol as an organic solvent, and the like. As the binder resin, for example, an amine-modified epoxy resin in which an amino group is added to the basic skeleton of a bisphenol type epoxy resin is used. The amine-modified epoxy resin is neutralized with, for example, an organic acid, immersed in the paint 5 in a state where the base material 4 is connected as a cathode and the metal plate 7 is connected as an anode, and is energized for about 3 minutes at a voltage of 100 V for cationic electrodeposition coating. To form an electrodeposition resin film 3 (electrodeposition step S3).

  Next, the electrodeposition resin film 3 is immersed in a water tank for about 1 minute or more and 10 minutes or less to attach ion exchange water to the surface of the electrodeposition resin film 3, thereby imparting hydrophilicity to the surface of the electrodeposition resin film 3 ( Hydrophilicity imparting step S4). In this step, the hydrophilic group 32 is imparted to the unreacted portion of the electrodeposition resin film 3, and hydrophilicity is imparted to the surface of the electrodeposition resin film 3.

  Next, as shown in FIG. 3, a silica particle tank 8 containing silica particles 2, for example, AEROSIL (registered trademark) OX50 manufactured by Nippon Aerosil Co., Ltd. in a solid state is prepared, and an electrodeposition resin film provided with hydrophilicity. 3 is submerged in the silica particle tank 8, and the silica particles 2 are adhered to the surface of the substrate 4 while being pulverized by the crusher 9 or the like (silica particle adhesion step S5).

  Here, the average particle diameter of the primary particles of the silica particles 2 to be adhered is 10 nm or more and 50 nm or less, and the average particle diameter of the primary aggregate in which the primary particles are aggregated is 80 nm or more and 2.5 μm or less. If the average particle size of the primary aggregate of the silica particles 2 is less than 80 nm, sufficient hydrophilicity cannot be obtained, and if it exceeds 2.5 μm, the surface irregularities of the electrodeposited resin film 3 become large, so that suspended matters in the air are caught. This is because it becomes easy and cracks easily occur.

  Next, for example, heating is performed at 90 ° C. or higher and about 180 ° C. or lower for 20 minutes, and a part of the silica particles 2 adhering to the electrodeposited resin film 3 is embedded in the surface layer of the electrodeposited resin film 3, and embedded silica particles While the silica particles 2 bonded to 2 by intermolecular force are exposed outside the surface layer, the electrodeposition resin film 3 is cured to form a cured resin film 31 (silica particle layer forming step S6). In the cured resin film 31, the silica particle layer 1 is formed by the silica particles 2 embedded in the surface layer and the exposed silica particles 2.

  In this way, the base material 4 of the metal part connected to the cathode or anode electrode is immersed in the paint 5, and a voltage is applied to form the electrodeposited resin film 3 on the base material 4. Water or an aqueous solution is formed on this surface. The silica particles 2 are adhered to the surface of the electrodeposition resin film 3 imparted with hydrophilicity. By curing this, a part of the adhered silica particles 2 is embedded in the surface layer of the electrodeposited resin film 3, and the cured resin film in which the silica particles 2 bonded to the embedded silica particles 2 are exposed outside the surface layer. 31 can be formed.

That is, as shown in FIG. 4, the cured resin film 31 has embedded portions 10 in which part of the silica particles 2 are embedded in the surface layer, and silica particles 2 bonded to the embedded silica particles 2 and outside the surface layer. A silica particle layer 1 composed of the exposed exposed portion 11 is formed.
The film thus formed has hydrophilicity due to the exposed portion 11 of the silica particle layer 1 and can prevent adhesion of a hydrophobic substance. And since the silica particle 2 of the exposed part 11 has adhered firmly to the silica particle 2 of the embedding part 10, it does not exfoliate and it can give a metal part stable antifouling property for a long period of time.

  Here, the thickness of the cured resin film 31 is preferably 50 times to 100 times, more preferably 55 times to 90 times the thickness of the silica particle layer 1. This is because if the cured resin film 31 is thin, sufficient corrosion resistance cannot be ensured, and if it is thick, adhesion to the substrate 4 is difficult to obtain.

  Further, the total thickness of the silica particle layer 1 and the cured resin film 31 is preferably 1 μm or more and 50 μm or less. If the thickness is less than 1 μm, sufficient corrosion resistance cannot be obtained, and if it exceeds 50 μm, sufficient adhesion to the substrate 4 cannot be obtained, and cracks are likely to occur.

  Thus, even if it uses for a long period of time, the silica particle 2 cannot peel easily, it can maintain the hydrophilicity and the metal component to which the durable antifouling function was provided can be obtained.

In the present embodiment, an example in which a binder resin dissolved or dispersed in water is used as the paint 5 is shown, but powder electrodeposition coating may be used.
For example, in an aqueous solution of a water-dilutable cationic resin obtained by adding an organic amino compound to an epoxy group in an epoxy resin and adding an acidic compound thereto, a synthetic resin powder such as an epoxy resin, a polyester resin, an acrylic resin powder, etc. Electrodeposition coating may be performed using a powder-containing cation-type electrodeposition paint obtained by dispersing.

  Moreover, although the example using cation type electrodeposition coating was shown in electrodeposition process S3, it is good also as anion type electrodeposition coating. If the base material 4 is connected to the anode electrode and the metal plate 7 is connected to the cathode electrode, for example, it is immersed in a paint 5 containing a binder resin to which a carboxylic acid is added and an amine for neutralizing the binder resin, and electrodeposition is applied. Good.

  Moreover, although the example using AEROSIL (trademark, the same hereafter) OX50 by Nippon Aerosil Co., Ltd. was shown as the silica particle 2 used, for example, using AEROSIL50, AEROSIL90G, AEROSIL130, AEROSIL150, AEROSIL200, AEROSIL300, AEROSIL380 Also good.

  Moreover, the sample was produced as follows and the average particle diameter of the primary aggregate of the silica particle 2 was measured. 100 mL of pure water was weighed into a 300 mL disposable cup, 3 g of AEROSILOX 50 was added, and dispersion was performed for 2 minutes at an output of 200 W using an ultrasonic disperser (US-600T manufactured by Nippon Seiki Seisakusho). The average particle diameter was measured using a laser light scattering measurement apparatus (LA-920 manufactured by Horiba, Ltd.).

  Although the example using the amine-modified epoxy resin that opens the epoxy ring of the bisphenol-type epoxy resin with an amine is shown as the binder resin included in the paint 5, a sulfonium-modified epoxy resin may be used. As the bisphenol type epoxy resin, a bisphenol A type oil-coated shell epoxy Epicoat (registered trademark, the same shall apply hereinafter) 828, Epicoat 1001, Epicoat 1010 and the like, bisphenol F type Epicoat 807 and the like may be used.

  Moreover, although the example which introduce | transduced the amino group into binder resin was shown, it is good also as a water dispersion type | mold by introduce | transducing basic groups, such as an ammonium base and a sulfonium base, and neutralizing these basic groups with an acid.

  Moreover, although the example which uses an organic acid as a neutralizing acid contained in the coating material 5 was shown, you may use inorganic acids, such as hydrochloric acid, nitric acid, phosphoric acid, formic acid, acetic acid, and lactic acid.

  The water contained in the paint 5 preferably has less ionic impurities such as calcium ions and magnesium ions for dispersion stability. It is preferable that the ionic impurity more than bivalence is 200 ppm or less, More preferably, it is 50 ppm or less.

  Although the example which used ethanol as an organic solvent contained in the coating material 5 was shown, n-propanol, 2-propanol, isobutyl alcohol, n-butyl alcohol, isoamyl alcohol, n-amyl alcohol, hexyl alcohol, 2-ethylbutyl alcohol, Methyl amyl alcohol, cyclohexanol, 2-ethylhexyl alcohol, octyl alcohol, benzyl alcohol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethyl lactate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol dimethyl ether, Diethylene glycol ethyl methyl ether, diethylene glycol Isopropyl methyl ether, dipropylene glycol monomethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol butyl methyl ether, tripropylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol monobutyl ether, ethylene glycol monophenyl ether, triethylene glycol monomethyl ether, diethylene glycol Dibutyl ether, triethylene glycol butyl methyl ether, polyethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol monomethyl ether, N-methyl-2-pyrrolidone, or the like may be used. You may use these individually or in combination of 2 or more types.

Further, the paint 5 may contain a pigment, for example, colored pigments such as titanium white, carbon black, cobalt, and bengara, extender pigments such as kaolin, talc, aluminum silicate, calcium carbonate, mica, and clay, phosphorus Zinc oxide, iron phosphate, aluminum phosphate, calcium phosphate, zinc phosphite, zinc cyanide, zinc oxide, aluminum tripolyphosphate, zinc molybdate, aluminum molybdate, calcium molybdate, aluminum phosphomolybdate, aluminum phosphomolybdate A rust preventive pigment such as zinc or a silicate compound such as zinc silicate, calcium silicate, or silica may be used.
Moreover, when using a pigment as a component of a paint, since the pigment is in a powder form, the pigment may be dispersed in an aqueous medium at a high concentration in advance to form a paste and then adjusted to the concentration at the time of use.

  Further, in the case of cationic electrodeposition coating, in order to improve the corrosion resistance of the cured resin film 31, the paint 5 may contain a metal catalyst as metal ions. As the metal ion, cerium ion, bismuth ion, copper ion, zinc ion, or the like may be used.

  In the hydrophilicity imparting step S4, the example in which the electrodeposited resin film 3 is immersed in the water tank has been shown, but ion-exchanged water may be sprayed on the surface of the electrodeposited resin film 3.

  As a method of attaching the silica particles 2 to the surface of the electrodeposited resin film 3, the method of sinking the electrodeposited resin film 3 in the silica particle tank 8 has been shown, but solid silica particles 2 may be sprayed on the surface.

  Moreover, in order to adhere the silica particles 2 uniformly on the surface of the electrodeposited resin film 3, after attaching the silica particles 2 to the substrate 4, it is preferable to remove excess silica particles 2 using an air flow. Excess silica particles 2 may be removed by rotating the substrate 4 instead of the air flow.

  In the electrodeposition step S3, an isocyanate such as tolylene diisocyanate can be used as the crosslinking agent for curing the electrodeposition resin film 3, for example.

  By using these, the corrosion resistance and antifouling property of the metal parts can be secured in the same manner.

Embodiment 2. FIG.
FIG. 5: is a schematic block diagram of the outdoor unit of the air conditioner concerning Embodiment 2 of this invention, and FIG. 6 is a schematic diagram of a heat exchanger.
As shown in FIG. 5, the outer unit of the outdoor unit 100 is configured by a casing 50, and a machine room 20 and a blower room 23 are provided in the casing 50.

  The machine room 20 is provided with a compressor 21 and an electrical component box 22. A control board (not shown) is provided inside the electrical component box 22. The control board is a member for controlling the rotation speed of the compressor 21 and driving a heater 30 and the like which will be described later.

The blower chamber 23 is provided with a heat exchanger 24, a fan 25, a fan motor 26, a fan motor support plate 27, an upper plate 28, and a support plate connection portion 29.
As shown in FIG. 6, the heat exchanger 24 includes fins 60 and copper tubes 61, and performs heat exchange of the outside air (gas) taken into the outdoor unit 100 from the intake port (not shown) of the housing 50. Has the function to perform. The silica particle layer 1 and the cured resin film 31 formed by the film forming method of the present invention are formed on at least one surface of the fin 60 and the copper tube 61.
The heat exchanger 24 is provided on the back side of the outdoor unit 100 with respect to the fan 25, the fan motor 26, the fan motor support plate 27, the upper plate 28, and the support plate connection portion 29. L-shaped and provided along the left side surface of the front side panel and the back panel.

  The fan 25 is a blower unit composed of, for example, a propeller fan. The fan 25 introduces outside air into the outdoor unit 100 through the intake port of the housing 50, and the outside air introduced into the outdoor unit 100 is transferred to the front side of the outdoor unit 100. It has the function to discharge toward. The fan 25 circulates outside air heat-exchanged by the heat exchanger 24.

The fan motor 26 is a driving unit that drives the fan 25 and is attached to the fan motor support plate 27 using a fixing unit such as a screw.
The fan motor support plate 27 is for supporting the fan motor 26.
The upper plate 28 is a plate-like member provided substantially horizontally with the bottom panel, for example. The upper plate 28 is a member for reinforcing the strength of the fan motor support plate 27 in consideration of the case where the fan motor 26 is enlarged, and is connected to the fan motor support plate 27. It is attached so as to be directed forward from the uppermost end.
The support plate connection portion 29 is a U-shaped member, for example, and is configured integrally with the fan motor support plate 27. The support plate connection portion 29 is provided such that the inner surface thereof is in contact with the upper surface of the heat exchanger 24. Thus, the fan motor support plate 27 is fixed to the heat exchanger 24 by attaching the support plate connection portion 29 to the heat exchanger 24.

  Thus, in the outdoor unit of the air conditioner of the present invention, the silica particle layer 1 having the cured resin film 31 and the embedded portion 10 and the exposed portion 11 on the surface of at least one of the fin 60 and the copper pipe 61. Since the heat exchanger 24 formed with is provided, hydrophobic dirt such as oil is difficult to adhere due to the air flow when the heat of the gas taken in from the intake port provided in the housing 50 is exchanged, Air conditioning performance can be improved.

  Hereinafter, the results of confirming the effects of the present invention by Examples 1 to 5 using the aluminum substrate 4 of 100 mm × 30 mm × 1 mm will be described.

Example 1.
In the degreasing step S1, the base material 4 was degreased using a neutral degreasing agent MGC13-B for aluminum manufactured by Murata and washed with water for 5 minutes. In the chemical conversion step S2, a 5-differential chemical conversion treatment was performed using a coating base chemical conversion agent MP-440 manufactured by Murata Co., Ltd., and washed with water for 5 minutes. Thereafter, in the electrodeposition step S3, the electrodeposition resin film 3 is formed by energization at 100V for 3 minutes using Nihon Paint Powernics Excel 1200 as the paint 5, and AEROSIL (registered trademark, the same applies hereinafter) manufactured by Nippon Aerosil Co., Ltd. After being submerged in the silica particle tank 8 filled with 150 and pulled up, it was heated at a temperature of 120 ° C. for 20 minutes to form a coating film. The average particle diameter of the primary aggregate of the silica particles 2 used at this time was 120 nm.

Example 2
In the degreasing step S1, the base material 4 was degreased using a neutral degreasing agent MGC13-B for aluminum manufactured by Murata and washed with water for 5 minutes. In the chemical conversion step S2, a 5-differential chemical conversion treatment was performed using a coating base chemical conversion agent MP-440 manufactured by Murata Co., Ltd., and washed with water for 5 minutes. After that, the electrodeposition resin film 3 is formed by energizing at 100 V for 3 minutes using Nihon Paint Co., Ltd. Powernics Excel 1200 as the paint 5, and after being submerged in the silica particle tank 8 filled with Nippon Aerosil Co., Ltd. And heated at 85 ° C. for 20 minutes to form a coating film. The average particle diameter of the primary aggregate of the silica particles 2 used at this time was 120 nm.

Example 3
In the degreasing step S1, the base material 4 was degreased using a neutral degreasing agent MGC13-B for aluminum manufactured by Murata and washed with water for 5 minutes. In the chemical conversion step S2, a 5-differential chemical conversion treatment was performed using a coating base chemical conversion agent MP-440 manufactured by Murata Co., Ltd., and washed with water for 5 minutes. After that, the electrodeposition resin film 3 is formed by energizing at 100 V for 3 minutes using Nihon Paint Co., Ltd. Powernics Excel 1200 as the paint 5, and after being submerged in the silica particle tank 8 filled with Nippon Aerosil Co., Ltd. The coating film was formed by heating at 195 ° C. for 20 minutes. The average particle diameter of the primary aggregate of the silica particles 2 used at this time was 120 nm.

Example 4
In the degreasing step S1, the base material 4 was degreased using a neutral degreasing agent MGC13-B for aluminum manufactured by Murata and washed with water for 5 minutes. In the chemical conversion step S2, a 5-differential chemical conversion treatment was performed using a coating base chemical conversion agent MP-440 manufactured by Murata Co., Ltd., and washed with water for 5 minutes. After that, the electrodeposition resin film 3 is formed by energizing at 100 V for 3 minutes using Nihon Paint Co., Ltd. Powernics Excel 1200 as the paint 5, and after being submerged in the silica particle tank 8 filled with Nippon Aerosil Co., Ltd. , And heated at 120 ° C. for 20 minutes to form a coating film. The average particle diameter of the primary aggregate of the silica particles 2 used at this time was 80 nm.

Example 5 FIG.
In the degreasing step S1, the base material 4 was degreased using a neutral degreasing agent MGC13-B for aluminum manufactured by Murata and washed with water for 5 minutes. In the chemical conversion step S2, a 5-differential chemical conversion treatment was performed using a coating base chemical conversion agent MP-440 manufactured by Murata Co., Ltd., and washed with water for 5 minutes. After that, the electrodeposition resin film 3 is formed by energizing at 100 V for 3 minutes using Nihon Paint Co., Ltd. Powernics Excel 1200 as the paint 5, and after being submerged in the silica particle tank 8 filled with Nippon Aerosil Co., Ltd. , And heated at 120 ° C. for 20 minutes to form a coating film. The average particle diameter of the primary aggregate of the silica particles 2 used at this time was 2.2 μm.

Comparative Example 1
In the degreasing step S1, the base material 4 was degreased using a neutral degreasing agent MGC13-B for aluminum manufactured by Murata and washed with water for 5 minutes. In the chemical conversion step S2, a 5-differential chemical conversion treatment was performed using a coating base chemical conversion agent MP-440 manufactured by Murata Co., Ltd., and washed with water for 5 minutes. After that, Nihon Paint Co., Ltd. Powernics Excel 1200 was used as the paint 5, and 10% by weight of a colloidal silica particle made by Nissan Chemical Co., Snowtex (registered trademark, hereinafter the same) OS was blended and energized at 100V for 3 minutes. The electrodeposited resin film 3 was formed and heated at 120 ° C. for 20 minutes to form a coating film. That is, the electrodeposition step S3 was performed by mixing the colloidal silica particles instead of the silica particles 2 in the paint 5.

Comparative Example 2
In the degreasing step S1, the base material 4 was degreased using a neutral degreasing agent MGC13-B for aluminum manufactured by Murata and washed with water for 5 minutes. In the chemical conversion step S2, a 5-differential chemical conversion treatment was performed using a coating base chemical conversion agent MP-440 manufactured by Murata Co., Ltd., and washed with water for 5 minutes. Thereafter, the electrodeposited resin film 3 is formed by applying current at 100 V for 3 minutes using Nihon Paint's Powernics Excel 1200 as the paint 5, and a silica solution tank filled with a 3% by weight aqueous solution of Snowtex OS manufactured by Nissan Chemical Co., Ltd. It was dipped in and pulled up. After pulling up from the silica solution tank, it was heated at 120 ° C. for 20 minutes to form a coating film. That is, colloidal silica in the form of solution instead of solid was used.

Comparative Example 3
In the degreasing step S1, the base material 4 was degreased using a neutral degreasing agent MGC13-B for aluminum manufactured by Murata and washed with water for 5 minutes. In the chemical conversion step S2, a 5-differential chemical conversion treatment was performed using a coating base chemical conversion agent MP-440 manufactured by Murata Co., Ltd., and washed with water for 5 minutes. Thereafter, the electrodeposition resin film 3 was formed by energizing at 100 V for 3 minutes using Nihon Paint Co., Ltd. Powernics Excel 1200 as the paint 5, and heated at 120 ° C. for 20 minutes to form a coating film. Thereafter, the substrate 4 on which the coating film was formed was immersed in a silica solution tank filled with a 3% by weight aqueous solution of Snowtex OS manufactured by Nissan Chemical Industries, and air blow dried.

Comparative Example 4
In the degreasing step S1, the base material 4 was degreased using a neutral degreasing agent MGC13-B for aluminum manufactured by Murata and washed with water for 5 minutes. In the chemical conversion step S2, a 5-differential chemical conversion treatment was performed using a coating base chemical conversion agent MP-440 manufactured by Murata Co., Ltd., and washed with water for 5 minutes. Thereafter, the electrodeposition resin film 3 was formed by energizing at 100 V for 3 minutes using Nihon Paint Co., Ltd. Powernics Excel 1200 as the paint 5, and heated at 120 ° C. for 20 minutes to form a coating film. That is, neither silica particles nor colloidal silica particles were used.

  For the coating films (cured resin film 31 and silica particle layer 1 or cured resin film 31) obtained by the film forming methods of Examples 1 to 5 and Comparative Examples 1 to 4, the initial contact angle using ion-exchanged water, Water resistance, corrosion resistance, and adhesion tests were evaluated.

  For the initial contact angle, the samples obtained in Examples 1 to 5 and Comparative Examples 1 to 4 were allowed to stand at room temperature (25 ° C.) for 1 hour, and a contact angle meter (CX-150, manufactured by Kyowa Interface Science) was used. Measured and evaluated according to the criteria in Table 1. From the tip of a needle having an inner diameter of 0.1 mm coated with PTFE (polytetrafluoroethylene), about 5 μL of water droplets are dropped onto the surface of the coating film, and the smaller the contact angle, the higher the hydrophilicity of the coating film. The results of this evaluation are shown in Table 1.

  For water resistance, the samples obtained in Examples 1 to 5 and Comparative Examples 1 to 4 were immersed in ion-exchanged water, left at room temperature (25 ° C.) for 200 hours, then taken out and left to stand for 1 hour. It measured using the meter (CX-150 type made from Kyowa Interface Science), and evaluated according to the reference | standard in Table 1. About 5 μL of water droplets are dropped on the surface of the coating film from the tip of a PTFE (polytetrafluoroethylene) -coated needle having an inner diameter of 0.1 mm. The smaller the contact angle, the higher the water resistance of the coating film. The results of this evaluation are shown in Table 1.

  As for the anticorrosive property, an artificial seawater combined cycle test was conducted as an accelerated test to reproduce the salt damage corrosion and shorten the evaluation period. An artificial seawater combined cycle test was conducted for 1920 hours on the samples obtained in Examples 1 to 5 and Comparative Examples 1 to 4 by a corrosion test combining a wet and dry cycle, a temperature cycle, and a spray of a corrosive liquid. The state was observed with a microscope and evaluated according to the criteria in Table 1. The larger the residual area of the coating film, the higher the corrosion resistance of the coating film. The results of this evaluation are shown in Table 1.

The adhesion is made to reciprocate 20 times with a load of 90 gf / cm ² using a wear tester clock meter (manufactured by Yasuda Kikai Co., Ltd.) with respect to the samples obtained in Examples 1 to 5 and Comparative Examples 1 to 4. A wear test was performed and evaluated according to the criteria in Table 1. The peeled state of the coating film after the abrasion test was observed using an electron microscope, and the remaining state of the coating film was image-processed to measure the remaining area. The larger the residual area of the coating film, the higher the adhesion between the substrate 4 and the coating film. The results of this evaluation are shown in Table 1.

  As shown in Table 1, the coating films formed under the conditions of Examples 1 to 5, particularly Example 1, are formed of the cured resin film 31 and the silica particle layer 1 and have a good initial contact angle and anticorrosion. The adhesiveness was also high, and high adhesion with the substrate 4 could be maintained.

On the other hand, in Comparative Example 1, colloidal silica particles are not deposited on the surface of the coating film formed on the coating material 5 in the electrodeposition step S3. Also in Comparative Example 2, since the colloidal silica particles enter the inside of the coating film, they are not deposited on the surface of the coating film. Therefore, it is difficult to obtain the effect of the initial contact angle in any case.
In Comparative Example 3, since the colloidal silica particles are adhered to the surface, the initial contact angle is good, but since it gradually peels off from the surface of the coating film, water resistance cannot be obtained.
Since neither the silica particles 2 nor the colloidal silica particles are contained in the coating film of Comparative Example 4, the anticorrosion property of the substrate 4 by the coating film can be obtained, but the evaluation of the antifouling property by the initial contact angle and water resistance is preferable. There wasn't.

  Thus, it turns out that the sample which formed the coating film by the cured resin film 31 of this invention by Examples 1-5 and the silica particle layer 1 is excellent in corrosion resistance and antifouling property.

  Note that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be modified or omitted as appropriate.

1 silica particle layer, 2 silica particles, 3 electrodeposition resin film, 4 base material, 5 paint,
6 paint tank, 7 metal plate, 8 silica particle tank, 9 crusher, 10 embedding part,
DESCRIPTION OF SYMBOLS 11 Exposed part, 20 Machine room, 21 Compressor, 22 Electrical component box, 23 Blower room,
24 heat exchanger, 25 fan, 26 fan motor, 27 fan motor support plate,
28 upper plate, 29 support plate connection part, 31 cured resin film, 32 hydrophilic group, 50 housing,
60 fins, 61 copper pipes, 100 outdoor units.

Claims (2)

An electrodeposition step of immersing an electrode and a metal substrate connected to the electrode in a paint, and applying a voltage to form an electrodeposition resin film on the metal substrate;
A hydrophilicity imparting step of attaching water or an aqueous solution to the surface of the electrodeposition resin film to impart hydrophilicity;
A silica particle attaching step of attaching silica particles to the electrodeposited resin film imparted with hydrophilicity;
At least a part of the silica particles is embedded in the surface layer of the electrodeposited resin film, and bonded to the embedded silica particles to cure the electrodeposited resin film while exposing the silica particles outside the surface layer of the electrodeposited resin film. Forming a cured resin film, and forming a silica particle layer on a surface layer of the cured resin film; and
A film forming method comprising:   2. The film forming method according to claim 1, wherein an average particle size of primary aggregates obtained by aggregating primary particles of silica particles used in the silica particle adhesion step is 80 nm or more and 2.5 μm or less.

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