JP2011235457A - Metal coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal coating material which has high water-repellency on a surface and has satisfactory workability upon press working.SOLUTION: A precoat aluminum plate 10 includes: an aluminum base material 11; a water-repellent coated film 13 formed on the surface of the aluminum base material 11; and a base coated film 12 interposed between the aluminum base material 11 and the water-repellent coated film 13 to improve adhesiveness between them. The water-repellent coated film 13 contains fluorine-containing resin as a water-repellent resin and contains polyethylene glycol as a lubricating component. The content of polyethylene glycol is 5 to 50 mass% with respect to the fluorine-containing resin and the amount of coated film of the water-repellent coated film is 0.01 to 3 g/mwith respect to the effective surface area of the aluminum base material.

Description

  The present invention relates to a metal coating material.

Various uses of the metal-coated plate have been proposed. In this specification, an example in which the metal-coated plate is applied to a fin material of a heat exchanger of an air conditioner will be described.
In a heat exchanger used for an air conditioner, a fin material having a large heat exchange area is coupled to a pipe through which a refrigerant circulated indoors and outdoors passes. Such a fin material has light weight, relatively high thermal conductivity, moderate mechanical properties, and excellent characteristics such as aesthetics, moldability, and corrosion resistance (anticorrosion). Therefore, aluminum or aluminum alloy material is used.

  And recently, in order to make the heat exchanger compact, the design is made such that the interval between adjacent fin materials is as narrow as possible. Thus, if the space | interval of adjacent fin material is narrowed, the heat transfer amount of a refrigerant | coolant and air will reduce and the thermal efficiency (heat exchange efficiency) of a heat exchanger will fall. Therefore, it is necessary to eliminate such a phenomenon.

  In such a heat exchanger, during the cooling operation of the air conditioner, moisture in the air may adhere to the surface of the fin material as condensed water. Since the surface of the fin material made of aluminum or aluminum alloy material is poor in water repellency and hydrophilicity, the condensed water is present in a semicircular shape on the surface of the fin material or in a bridge shape between adjacent fin materials. To come.

  Such a phenomenon hinders the flow of air passing between the fin materials, increases ventilation resistance, and greatly reduces the thermal efficiency of the air conditioner, so such condensed water is excluded from the surface of the fin materials and between the fin materials. It is necessary to do.

For this purpose, one of the following measures can be considered.
(1) A hydrophilic film is formed on the fin surface, and condensed water is flowed down into a thin water film.
(2) A water-repellent film is formed on the fin surface to prevent adhesion of condensed water.

  As a specific example of the above (1), for example, a technique has been proposed in which a composition containing carboxymethyl cellulose and polyethylene glycol is applied to the fin surface to form a hydrophilic film (see, for example, Patent Document 1).

  On the other hand, as a specific example of the above (2), for example, a technique for forming a water-repellent film on the fin surface by containing a silicone-based or fluorine-based inorganic filler as the water-repellent film (for example, is proposed) Patent Documents 2 and 3).

Japanese Patent Laid-Open No. 2000-028291 JP-A-3-244680 Japanese Patent Laid-Open No. 5-222339

  According to the technique described in Patent Document 1, when the heat exchanger is used indoors, condensed water is effectively eliminated by the hydrophilic film, and a satisfactory result is obtained. However, in particular, when the heat exchanger is used indoors in winter, there is a problem that the condensed water freezes on the surface of the fin material and becomes frost, thereby reducing the heating performance.

  On the other hand, according to the techniques described in Patent Documents 2 and 3, since the surface of the fin material becomes water-repellent, the lubricating oil used when the fin material is formed by press working does not sufficiently adhere to the surface of the fin material. During the press working, the fin material was cracked. In press work, in order to solve the problem of deterioration of workability, such as cracks and galling in the metal coating material that is generally the work piece, or die life and tool life due to increased friction, Lubricating oil (molding oil) is used in this way to give lubricity to the surface of the metal coating material. Here, the “metal coating material” means a material in which a water repellent film is formed on the surface of a metal substrate.

  The present invention has been made in view of such problems, and an object thereof is to provide a metal coating material having high surface water repellency and good workability during press working.

In order to achieve the above object, a metal coating material according to the first aspect of the present invention comprises a metal base material, and a water-repellent film formed on the surface of the metal base material,
The water-repellent film contains a water-repellent resin composed of a fluorine-based resin or a silicone-based resin, and a polyether compound having a hydroxyl group at a terminal as a lubricating component,
The content of the lubricating component is 5 to 50 mass% with respect to the water-repellent film, and the film amount of the water-repellent film is 0.01 to 3 g / m ² with respect to the surface area of the metal substrate. is there,
It is characterized by that.

  The lubricating component is preferably at least one selected from the group consisting of polyethylene glycol, polypropylene glycol, ethylene glycol / propylene glycol copolymer, and ethylene glycol / propylene glycol copolymer.

  The lubricating component is preferably polyethylene glycol having a weight average molecular weight of 4000 to 40000.

The metal coating material further comprises a base film between the metal substrate and the water repellent film,
The base film is an organic film and includes at least one resin component selected from an epoxy resin, a polyester resin, an acrylic resin, and a urethane resin, and the amount of the base film is the metal group It is preferable that it is 0.01-10 g / m < ² > with respect to the surface area of a material.

Between the metal substrate and the base film, a chemical conversion treatment film is provided,
The chemical conversion film is at least one selected from the group consisting of chromium, zirconium and titanium, and preferably contains 5 to 15 mg / m ² of metal in terms of metal element.

The undercoat contains inorganic fine particles in the resin component;
It is preferable that the content of the inorganic fine particles is 5 to 50 mass% with respect to the base film.

  According to the present invention, a metal coating material having high surface water repellency and good workability during press working can be obtained.

It is a schematic cross section which shows the layer structure of the coating metal plate which concerns on embodiment of this invention. It is a schematic cross section which shows the layer state of the coating metal plate in the state in which the silica fine particle is contained in the base film. (A)-(c) is a schematic cross section for demonstrating the manufacturing method of a coating metal plate.

  Hereinafter, the manufacturing method of the precoat aluminum plate (metal coating material) which concerns on embodiment of this invention, a coating material, and a precoat aluminum plate is demonstrated.

  As shown in FIG. 1, a precoated aluminum plate 10 as a metal coating material according to an embodiment of the present invention includes an aluminum base (metal base) 11 and a water-repellent coating formed on the surface of the aluminum base 11. 13 and a base coating 12 interposed between the aluminum base 11 and the water repellent coating 13.

  The water-repellent coating 13 includes a water-repellent resin having water repellency as a water-repellent component, thereby imparting appropriate water repellency to the surface of the precoated aluminum plate 10.

  The base film 12 is a film formed on the surface of the aluminum substrate 11 in order to improve the coating film adhesion (adhesion) between the aluminum substrate 11 and the water repellent film 13. The undercoat 12 is also formed to impart corrosion resistance to the surface of the aluminum base 11. In addition, when sufficient coating-film adhesiveness is obtained between the aluminum base material 11 and the water-repellent film 13, the base film 12 can be omitted.

  Hereinafter, the aluminum base material 11, the base film 12 (including silica fine particles (inorganic fine particles)), and the water-repellent film 13 (including water-repellent resin, lubricating components, and other additives) will be described in more detail.

<Aluminum substrate>
As the aluminum substrate 11, for example, an aluminum plate or an aluminum alloy plate can be used.
In addition, as a metal substrate other than an aluminum plate or an aluminum alloy, iron, an iron alloy (including stainless steel) and its plated steel plate, copper, a copper alloy (including brass) and its plated steel plate, and magnesium, a magnesium alloy, Titanium, titanium alloy, etc. can also be used.

<Undercoat>
Examples of the base film 12 include a chemical conversion film, a corrosion-resistant organic film, an anodized film, and a boehmite film. From the viewpoint of corrosion resistance, coating film adhesion, and economy, it is preferable to use a chemical conversion treatment film or an organic corrosion resistance film.

As the chemical conversion coating, a chromium-based, zirconium-based, or titanium-based chemical conversion coating is used. From the viewpoint of corrosion resistance and coating film adhesion, a chromium-based chemical conversion coating is preferable. As a method for forming the chemical conversion treatment film, a coating type, electrolytic type, reaction type chemical conversion treatment method, or the like is used, but any method may be used. The drying temperature is also arbitrary. Among the methods for forming the chemical conversion coating, it is preferable to use a coating type chromate method excellent in moldability, coating film adhesion, and corrosion resistance. The coating amount in this case is ² to 50 mg / m ² in terms of metal element. If the coating amount is less than 2 mg / m ^{2 in} terms of metal element, sufficient corrosion resistance and adhesion cannot be obtained. Moreover, even if it exceeds 50 mg / m < ² >, the effect of corrosion resistance and coating-film adhesiveness will be saturated, and it will lack economical efficiency. A preferable coating amount is 5 to 15 mg / m ² in terms of metal element.

An organic corrosion-resistant film is preferable because it has particularly excellent corrosion resistance.
As the organic corrosion-resistant film, a resin film made of at least one selected from the group consisting of an epoxy resin, a polyester resin, an acrylic resin, and a urethane resin is used. In addition, as long as the water repellency and workability of the resin film formed on it are not impaired, any resin film can be used. The formation amount of the organic corrosion-resistant film is 0.1 to 10 g / m ² , preferably 0.5 to 5 g / m ² . If it is less than 0.1 g / m ² , sufficient corrosion resistance cannot be obtained, and if it exceeds 10 g / m ² , the effect is saturated and uneconomical.

  In addition, in the precoat aluminum plate (metal coating material) 10, by providing a chemical conversion treatment film between the aluminum base material (metal base material) 11 and the base film 12, corrosion resistance and adhesiveness are further improved. Thus, it is preferable to use a chemical conversion film and an organic corrosion-resistant film as the base film 12 and a chemical conversion film different from the base film 12 in combination.

  Further, in order to form unevenness on the surface of the organic corrosion-resistant film, it is preferable to contain inorganic fine particles, specifically, silica fine particles 14 as shown in FIG. As a result, the irregular shape 14a is formed on the surface of the water repellent film 13 and the surface area is increased, so that the water repellency of the water repellent film 13 is further enhanced. As the inorganic fine particles, alumina fine particles, titanium oxide fine particles and the like can also be used.

(Silica fine particles)
The content of the silica fine particles 14 is 5 to 50 mass% (wt%), preferably 10 to 35 mass%, with respect to the base film 12. When the content of the silica fine particles 14 is less than 5 mass%, the formation of the uneven shape 14a on the surface of the water repellent coating 13 becomes insufficient, and the effect of increasing the water repellency of the water repellent coating 13 is insufficient. On the other hand, when the content of the silica fine particles 14 exceeds 50 mass%, the base coating 12 is easily peeled off from the base coating 12 due to the excessive silica fine particles 14 present at the interface between the base coating 12 and the base coating 12. And the adhesion between the water-repellent coating 13 are lowered.

  Further, the silica fine particles 14 have an average particle diameter of 3 to 3 from the viewpoint of ensuring the water repellency of the water repellent coating 13, the adhesion between the undercoat 12 and the water repellent coating 13, and the surface shape. 15 μm, preferably 6 to 12 μm may be used.

<Water repellent film>
The water repellent film 13 is a film containing a water repellent resin. The water repellent coating 13 contains a lubricating component and, if necessary, other additives in addition to such a water repellent resin.

(Water repellent resin)
As the water repellent resin, fluorine resin and silicone resin can be used. Especially, since both water repellency and coating-film adhesiveness are favorable, it is preferable to use a fluorine resin.

  Any fluororesin can be used without particular limitation as long as it contains fluorine atoms. Specifically, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE) , Tetrafluoroethylene-ethylene copolymer (ETFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), polyvinylidene fluoride (PVdF), polyvinyl fluoride (PVF), or a mixture thereof may be used. it can.

  As the silicone resin, silicon resin resin, dimethyl silicone resin, or a mixture thereof can be used.

(Lubricity component)
In the present embodiment, the lubricating component added to the water-repellent resin is distributed in a layered manner on the outermost surface of the water-repellent coating 13, and when forming the fin material of the heat exchanger for an air conditioner by pressing, Similar to the lubricating oil described in the background art, it has a function of imparting lubricity to the surface of a metal coating material that is a workpiece and enhancing the workability of press working.

  As the lubricating component, a polyether compound having a hydroxyl group at the end, specifically, from the group consisting of polyethylene glycol, polypropylene glycol, ethylene glycol / propylene glycol copolymer, polypropylene glycol and ethylene glycol / propylene glycol copolymer Examples thereof include at least one selected.

  In the case where the precoated aluminum plate 10 of the present embodiment is incorporated as a fin material in a heat exchanger of an air conditioner, the lubricating component is water-soluble and hydrophilic, so that the water repellency covering the fin material If the layer is distributed on the surface of the film 13, the water repellency of the water-repellent film 13 is impaired. However, since the lubricating component is water-soluble in this way, it is washed away by the condensed water adhering to the surface of the fin material during the cooling operation of the air conditioner and does not remain on the surface of the fin material. For this reason, in the precoat aluminum plate 10 which concerns on this embodiment, it is not necessary to provide the removal process of the said lubricating component so that the water repellency may not be impaired by the lubricating component.

  As the lubricating component, it is preferable to use polyethylene glycol (hereinafter abbreviated as “PEG”) because it is easily available industrially, is relatively inexpensive, and has a small environmental load.

  When PEG is used as the lubricating component, the weight average molecular weight is 4,000 to 40,000, preferably 10,000 to 40,000. If the weight average molecular weight is less than 4000, the lubricity of the water-repellent coating 13 is insufficient, and the workability of the precoated aluminum plate 10 during press working is reduced. On the other hand, when the weight average molecular weight exceeds 40000, the lubricity of the water-repellent coating 13 is lowered, the workability during press working is lowered, and the water repellency is impaired.

  For example, gel permeation chromatography (GPC: Gel Permeation Chromatography) can be used to measure the weight average molecular weight of the lubricating component from the precoated aluminum plate 10 that is the obtained metal-coated plate. Here, PEG, which is a lubricating component, is extracted from the obtained precoated aluminum plate 10 with water, the obtained aqueous PEG solution is drawn into GPC, and the weight average molecular weight is measured.

  Further, the content of PEG is 5 to 50 mass%, preferably 8 to 45 mass%, more preferably 15 to 20 mass% with respect to the water-repellent coating 13 obtained on the surface of the precoated aluminum plate 10. If the content of PEG is less than 5 mass%, the workability at the time of press working is lowered. On the other hand, when the content of PEG exceeds 50 mass%, the content of the water-repellent resin becomes relatively small, and the water-repellent film 13 is insufficient in water repellency.

(Other additives)
In addition, the water-repellent coating 13 may be rust preventives such as tannic acid, gallic acid, phytic acid, phosphinic acid, polyalcohol alkyl esters, polyethylene oxide condensate, etc., depending on the properties required for the precoated aluminum plate 10. Leveling agents, fillers such as polyacrylamide and polyvinylacetamide added within a range that does not impair the compatibility, colorants such as phthalocyanine compounds, additives such as surfactants such as alkyl sulfate esters and alkylsulfosuccinates. It may be contained.

<Method for producing precoated aluminum plate 10>
Hereinafter, the manufacturing method of the precoat aluminum plate 10 which concerns on this embodiment is demonstrated.
As shown in FIG. 3A, first, a base coating 12 is formed on the surface of the prepared aluminum substrate 11 by a coating type chromate method. Here, in addition to the coating-type chromate method, an organic corrosion-resistant film can be formed by using a resin film made of at least one selected from the group consisting of an epoxy resin, a polyester resin, an acrylic resin, and a urethane resin. Moreover, the said organic corrosion-resistant film | membrane can also be formed on a coating type chromate.

Next, as shown in FIG. 3B, a liquid film composition 15 that is a material of the water-repellent film 13 is applied (painted) from the surface of the base film 12 on the surface of the aluminum substrate 11 by a roll coater method. To do.
Here, the coating composition 15 includes a water-repellent resin such as a fluorine-based resin and a silicone-based resin as a water-repellent component constituting the water-repellent coating 13, a lubricating component such as PEG, and other additives as necessary. It can be prepared by dissolving and dispersing in a solvent such as water.
Any solvent can be used without particular limitation as long as it can dissolve or disperse each compound component constituting the water-repellent coating 13. Specifically, aqueous solvents such as water, ketone solvents such as acetone, alcohol solvents such as ethanol, ethylene glycol alkyl ether solvents such as ethylene glycol monoethyl ether; diethylene glycol alkyl ether solvents such as diethylene glycol monobutyl ether Solvents, esterified products of propylene glycol alkyl ether solvents such as propylene glycol monomethyl ether, and a series of glycol alkyl ether solvents such as ethylene glycol monoethyl ether acetate, or mixtures thereof can be used. Among these, from the viewpoint of reducing environmental burden, an aqueous solvent can be preferably used, and water can be particularly preferably used.

  In addition to the roll coater method described above, various methods such as a roll squeeze method, a chemicoater method, an air knife method, an immersion method, a spray method, and an electrostatic coating method can be used as the coating method of the coating composition 15. Among them, it is preferable to use a roll coater method in which the obtained water repellent coating 13 has uniform performance and good productivity. As the roll coater method, for example, a gravure roll method with easy coating amount management, a natural coating method suitable for thick coating, a reverse coating method suitable for imparting an aesthetic appearance to the coated surface, and the like can be employed.

Furthermore, the coating amount of the coating composition 15 is such that the coating amount of the water-repellent coating 13 is 0.01 to ³ g / m ² , preferably 0.05 to ² g / m ² with respect to the surface of the aluminum substrate 11. It is good to be. If the coating amount is less than 0.01 g / m ² , the desired water repellency or press workability cannot be obtained, and if it exceeds 3 g / m ² , the water repellency of the water-repellent coating is saturated and is not good. It becomes economy and is not preferable.

  Subsequently, as shown in FIG. 3 (c), this laminate is heated and dried at 70 to 300 ° C. using an oven 16, so that the coating composition 15 is applied from above the base coating 12 to the aluminum substrate 11. Bake on the surface. Thereby, the water-repellent film 13 is formed on the surface of the aluminum substrate 11 via the base film 12, and the precoated aluminum plate 10 is obtained. In addition, for the heating and drying of the water-repellent coating 13 here, a dielectric heating method can be used in addition to the normal heating method using the heater 16 described above.

  By further pressing the precoated aluminum plate 10 thus manufactured, a molded product such as a fin material of a heat exchanger for an air conditioner can be created. As the molded product, a fin material of a heat exchanger for an air conditioner is particularly preferable. However, the molded product is not limited to the fin material, and other molded products such as a parabolic antenna can also be used.

  According to the precoated aluminum plate 10 according to the present embodiment, the surface resistance value of the water-repellent coating 13 is lowered by a lubricating component such as PEG. For this reason, moderate lubricity is demonstrated at the time of press work, and workability becomes good. Further, since the water repellency of the water repellent film 13 is high, for example, by forming the fin material of a heat exchanger for an air conditioner, the condensed water adhering to the fin material when the air conditioner is operated can be effectively eliminated. Can do. For this reason, the heat exchanger using this fin material exhibits excellent heat exchange efficiency over a long period of time, and the life of the air conditioner is extended.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples in which a precoated aluminum plate is applied to a fin material of a heat exchanger for an air conditioner. The technical idea of the present invention is not limited to these examples.

(Examples 1-21, Comparative Examples 1-6)
As shown in Table 1, in Examples 1 to 21 and Comparative Examples 1 to 6, a water-repellent film was formed on the surface of an aluminum alloy plate, which is an aluminum substrate, as follows, and a precoated aluminum plate was produced. .

That is, first, an aluminum alloy plate (1100-H24 material, 0.100 mm thick) was prepared. The aluminum alloy plate was degreased with weak alkali, washed with water, and then dried.
Next, in Example 2 and Comparative Examples 1 to 6, coating type chromate (SAT427 manufactured by Nippon Paint Co., Ltd.) was applied to the surface of the aluminum alloy plate thus treated, and heated at 180 ° C. and baked for 10 seconds. In addition, a coating-type chromate-based chemical conversion film having a chromium adhesion amount of 10 mg / m ^{2 in} terms of metallic chromium was formed as a base film.

  In Examples 3 to 21, an epoxy resin, a polyester resin, an acrylic resin, or a urethane resin is used for the base treatment, and the base coat is formed with an organic corrosion-resistant coating by baking at 240 ° C. for 10 seconds. Formed. In Example 1, the base film was not formed on the surface of the aluminum alloy plate. Although not shown in Table 1, in Examples 3, 8 and 14, a coating type chromate-based chemical conversion film was formed under the organic corrosion-resistant film of the epoxy resin.

  In Examples 6 to 21 (except Examples 7 and 8), silica fine particles (with an average particle diameter of 7 μm) were added to the epoxy resin. In Example 7, alumina fine particles (with an average particle size of 5 μm) were added to the epoxy resin, and in Example 8, silica fine particles (with an average particle size of 7 μm) were added to the polyester resin. In Examples 3 to 5, silica fine particles are not added to the resin component for the base treatment.

  Thereafter, with respect to the aluminum alloy plate thus treated, in each example and each comparative example, the water-repellent component and the lubricating component shown in Table 1 (polypropylene glycol (PPG) in Example 13 and PEG in other Examples). Were mixed to prepare a film composition (water repellent film composition). Furthermore, this coating composition was applied to the surface of the aluminum alloy plate from above the base coating using a bar coater.

Thereafter, using an oven, the coating composition was baked on the surface of the aluminum alloy plate by heating for 20 seconds in a state where the surface temperature (PMT) of the aluminum alloy plate was approximately 80 ° C., to obtain a precoated aluminum plate.
The precoated aluminum plate thus obtained was measured for water repellency, workability (lubricity, formability), and coating film adhesion by the methods described below. The results are shown in Table 1.

In Examples 3 to 21, the resin materials (components) used for forming the base film are as follows.
・ Epoxy resin (bisphenol A type epoxy resin modified with carboxyl group-containing acrylic resin, epoxy equivalent: about 3800)
・ Polyester resin (terephthalic acid + isophthalic acid / ethylene glycol, number average molecular weight: 15000)
Acrylic resin (polyacrylic acid polymer, number average molecular weight: 9000)
-Urethane resin (tolylene diisocyanate / polyethylene glycol, number average molecular weight: 100,000)

Moreover, in each Example and each comparative example, the resin material (component) used for the water-repellent component is as follows.
・ Epoxy resin (Ester type epoxy resin in which acrylic resin is added to bisphenol A epoxy resin, epoxy equivalent: about 3800)
・ Fluorine resin (Fluorosurf FS-6010 manufactured by Fluro Technology)

注 ※ ）金属クロム換算にてクロム付着量（ｍｇ／ｍ^２）を表示。
略語対照）ＥＰＯ：エポキシ系樹脂
ＰＥＴ：ポリエステル系樹脂
ＡＣＲ：アクリル系樹脂
ＵＲＥ：ウレタン系樹脂
ＣＨＣ：塗布型クロメート
ＳＩＰ：シリカ微粒子
ＡＩＰ：アルミナ微粒子
ＦＬＲ：フッ素系樹脂
ＰＥＧ：ポリエチレングリコール
ＰＰＧ：ポリプロピレングリコール
ＳＴＮａ：ステアリン酸ナトリウム

Note *) The amount of chromium deposited (mg / m ² ) is displayed in terms of metallic chromium.
Abbreviation control) EPO: Epoxy resin
PET: Polyester resin
ACR: Acrylic resin
URE: Urethane resin
CHC: Coating type chromate
SIP: Silica fine particles
AIP: Alumina fine particles
FLR: Fluorine resin
PEG: Polyethylene glycol
PPG: Polypropylene glycol
STNa: Sodium stearate

  In addition, about the precoat aluminum plate obtained by each Example and each comparative example, water repellency, workability (lubricity, moldability), and coating-film adhesiveness were measured by the method shown below.

[Water repellency]
Each precoat aluminum plate was immersed in pure water for 30 minutes, and then the water repellency was evaluated by measuring the contact angle of water droplets attached to the surface of the precoat aluminum plate using a goniometer.
Regarding water repellency, symbols ◎, ○, △, and X shown in Table 1 correspond to the following, among which ◎ and ○ satisfy the performance required for the fin material, and pass. Means that.
◎: Contact angle is 130 ° or more ○: Contact angle is 100 ° or more and less than 130 ° △: Contact angle is 80 ° or more and less than 100 ° ×: Contact angle is less than 80 °

[Processability]
About each precoat aluminum plate, the press material was used, the fin material was shape | molded by drawless shaping | molding, and the following lubricity and moldability as workability were evaluated.
In this drawless molding, AF-2C (model number) manufactured by Idemitsu Kosan Co., Ltd. was used as a volatile press oil, the ironing rate was 58%, and the molding speed was 250 spm.

(Lubricity)
For each precoated aluminum plate, AF-2C (Idemitsu Kosan Co., Ltd.) was applied with 100 g load and 1/2 inch diameter stainless steel sphere using a Bowden type friction coefficient measuring instrument, and the coefficient of dynamic friction when sliding back and forth 15 times. The lubricity was evaluated by measuring.
Regarding lubricity, the symbols ◎, ○, △, and X shown in Table 1 correspond to the following, among which ◎ and ○ indicate that the evaluation results satisfy the performance required for the fin material and are acceptable. Means that.
◎: Less than 0.05 ○: 0.05 or more and less than 0.10 Δ: 0.10 or more and less than 0.15 ×: 0.15 or more

(Formability)
About the moldability, it performed by observing visually the state which shape | molded the fin material from each precoat aluminum plate. The symbols ◎, ○, △, and X shown in Table 1 correspond to the following, respectively, and ◎ and ○ among them mean that the evaluation results satisfy the performance required for the fin material and pass. .
◎: Very good ○: Good △: Scratches occur on the inner surface of the collar part ×: Defects (buckling, color jumping)

[Coating film adhesion]
According to JIS H4001, the aluminum base material, the water-repellent film and the coating film adhesion were evaluated. And about each precoat aluminum plate, the coating-film adhesiveness was evaluated by measuring the remaining number after tape peeling in a grid. The symbols ◯ and X shown in Table 1 correspond to the following, respectively, and ◯ among them means that the evaluation result satisfies the performance required for the fin material and is acceptable.
○: Coating film remaining rate 100%
X: Coating film residual ratio less than 100%

  As shown in Table 1, in each of Examples 1 to 21, the evaluation results passed for all evaluation items of water repellency, workability (lubricity, moldability), and coating film adhesion. Especially, since Examples 6-21 formed the base film containing silica fine particles (except for Example 7) and alumina fine particles (Example 7) on the surface of the aluminum base before forming the water-repellent film, It can be seen that it exhibits excellent water repellency.

On the other hand, as for Comparative Examples 1-6, any one evaluation result in water repellency, workability (lubricity, moldability), and coating-film adhesiveness failed.
That is, in Comparative Example 1, the film on the surface of the aluminum base material was an epoxy-based film that was not a water-repellent film. In Comparative Example 2, since the water-repellent coating did not contain a lubricity component, the lubricity and formability as workability were rejected. Further, Comparative Example 3 failed in terms of lubricity and moldability because sodium stearate, which is not a lubricating component, was included instead of PEG, which was a lubricating component. Further, Comparative Example 4 failed in terms of lubricity and workability because the content of the lubricating component contained in the water-repellent film was insufficient. Moreover, since the content of the lubricity component contained in the water-repellent film was excessive in Comparative Example 5, the film adhesion was rejected. Further, Comparative Example 6 failed in all of the water repellency, lubricity and formability because the amount of the water repellent film on the surface of the aluminum base material was insufficient.

  Various embodiments and examples can be made without departing from the broad spirit and scope of the present invention. The above-described embodiments and examples are for explaining the present invention and do not limit the scope of the present invention.

10 Metal painted plate 11 Metal base (aluminum or aluminum alloy plate)
12 Base film 13 Water repellent film (Water repellent resin + PEG)
14 Silica fine particles (inorganic fine particles)
14a Uneven shape on the surface of the water-repellent film 15 Liquid film composition 16 Oven

Claims (6)

A metal substrate, and a water-repellent film formed on the surface of the metal substrate,
The water-repellent film contains a water-repellent resin composed of a fluorine-based resin or a silicone-based resin, and a polyether compound having a hydroxyl group at a terminal as a lubricating component,
The content of the lubricating component is 5 to 50 mass% with respect to the water-repellent film, and the film amount of the water-repellent film is 0.01 to 3 g / m ² with respect to the surface area of the metal substrate. is there,
Metal coating material characterized by that.   The lubricating component is at least one selected from the group consisting of polyethylene glycol, polypropylene glycol, ethylene glycol / propylene glycol copolymer, and ethylene glycol / propylene glycol copolymer. The metal coating material described.   The metal coating material according to claim 1 or 2, wherein the lubricating component is polyethylene glycol having a weight average molecular weight of 4000 to 40000. The metal coating material further comprises a base film between the metal substrate and the water repellent film,
The base film is an organic film and includes at least one resin component selected from an epoxy resin, a polyester resin, an acrylic resin, and a urethane resin, and the amount of the base film is the metal group It is 0.01-10 g / m < ² > with respect to the surface area of a material, The metal coating material of any one of Claims 1-3 characterized by the above-mentioned. Between the metal substrate and the base film, a chemical conversion treatment film is provided,
The said chemical conversion treatment film is at least one selected from the group consisting of chromium, zirconium, and titanium, and contains 5 to 15 mg / m ² of metal in terms of metal element. Metal coating material of any one of 1-4. The undercoat contains inorganic fine particles in the resin component;
The metal coating material according to claim 4, wherein a content of the inorganic fine particles is 5 to 50 mass% with respect to the base film.

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