JP5056090B2 - Aluminum coating material and manufacturing method thereof - Google Patents

Description

  The present invention relates to an aluminum coating material having a coating film on the surface of an aluminum material made of aluminum or an aluminum alloy and a method for producing the same, and particularly requires a surface treatment using a chromium-based treatment agent such as chromate treatment or phosphoric acid chromate treatment. The present invention relates to an aluminum coating material excellent in both corrosion resistance and adhesion and a method for producing the same.

  Aluminum coating materials are lightweight and have excellent workability, and as an extruded shape and plate material, various types of interiors such as railway vehicle interiors, building interiors and exteriors such as building windows and entrance fittings, exterior walls and interiors of buildings, etc. Building materials, road materials, various cabinets, refrigerated car container interior and exterior, refrigerated showcases, various home appliances, various daily necessities, etc.

  And when manufacturing such an aluminum coating material, in general, for the purpose of improving the corrosion resistance of the aluminum material and improving the adhesion to the coating film, a so-called coating ground treatment is applied to the surface of the aluminum material. In addition, as the coating ground treatment, an anodizing treatment is performed to form an anodized film layer, or a so-called chromate treatment such as a chromate chromate treatment or a phosphoric acid chromate treatment is applied to form a chemical film. A layer is formed.

  However, in recent years, the movement of regulations on environmentally hazardous substances has been increasing worldwide, and since hexavalent chromium used in chromate treatment is harmful, the EU has already begun regulations on hexavalent chromium. In addition, self-regulation by companies has begun in Japan. In addition, with regard to the phosphoric acid chromate treatment, the chromium compound used is trivalent chromium and there is no legal restriction at present. However, there is a report that part of the chromium compound changes to hexavalent chromium when heated. However, development of a so-called non-chromium and environmentally friendly paint substrate treatment is desired.

  Therefore, the present inventors previously provided aluminum having a silicon-containing coating film containing silicon element on the surface of an aluminum material having a contact angle of 30 ° or less as an aluminum coating material that is non-chromium and has excellent corrosion resistance. A coating material was proposed (Japanese Patent Laid-Open No. 2004-283,824).

  Although this aluminum coating material achieves the initial purpose of exhibiting excellent corrosion resistance while being non-chromium, it contacts the surface of the aluminum material before forming a silicon-containing coating on the surface of the aluminum material. A pretreatment for making the angle 30 ° or less is indispensable. As this pretreatment, alkali treatment, acid treatment, surfactant solution treatment, degreasing treatment with an organic solvent, a silicon-containing compound solution is applied and dried. One kind of treatment selected from the pretreatment or the like or a treatment comprising a combination of two or more kinds is performed. However, waste solution treatment of the solution or solvent used in these pretreatments is required. For this reason, from the viewpoint of protecting the global environment, development of pre-coating treatment that does not generate waste liquid and paint base treatment that does not use harmful substances is desired.

  In addition to the environmental issues, in addition to the above-mentioned paint pretreatment that does not generate waste liquid and the development of paint base treatment that does not use harmful substances, the paint system used for paints is also a solvent system that uses conventional organic solvents. It is desirable to move from paint to water-based paint, but in order to provide a paint film on the surface of an aluminum material using water-based paint, the surface of the aluminum material must not be hydrophobic. Need to be made hydrophilic.

JP 2004-283,824

Therefore, the present inventors have made it possible to apply a water-based paint by making the surface of the aluminum material hydrophilic by a coating pretreatment that does not generate waste liquid or a coating base treatment that does not use harmful substances, and it is also possible to apply corrosion resistance and adhesion. As a result of diligent research on an aluminum coating material having a coating film with excellent properties, a hydrophilic film having a contact angle of 30 ° or less was previously formed on the surface of the aluminum material by ozone surface treatment using an ozone-containing gas. It was found that the object can be achieved by forming a silicon oxide-containing film on the surface of the film and providing a coating film on the silicon oxide-containing film, thereby completing the present invention.

Accordingly, an object of the present invention is to form a coating film through a hydrophilic film formed on the surface of an aluminum material and a silicon oxide-containing film formed thereon, thereby treating waste liquid and using harmful substances. It is providing the aluminum coating material which has a coating film excellent in corrosion resistance and adhesiveness.

Another object of the present invention is to form a hydrophilic film on the surface of the aluminum material by ozone surface treatment, and to form a silicon oxide-containing film on the surface of the hydrophilic film, thereby treating waste liquids and harmful. It is possible to apply a water-based paint by making the surface of an aluminum material hydrophilic without performing a pretreatment that requires the use of a substance, and it is also easy to produce an aluminum coating material having a coating film with excellent corrosion resistance and adhesion. It is providing the manufacturing method of the aluminum coating material which can be manufactured.

That is, the present invention is an aluminum coating material having a coating film on the surface of an aluminum material made of aluminum or an aluminum alloy, and the coating film has a hydrophilic film provided on the surface of the aluminum material and the surface of the hydrophilic film. provided through the formed silicon oxide-containing coating on, also, the hydrophilic coating, is formed by the ozone surface treatment using an ozone-containing gas that the contact angle is 30 ° or less It is a featured aluminum paint.

The present invention is also a method for producing an aluminum coating material having a coating film on the surface of an aluminum material made of aluminum or an aluminum alloy. The surface of the aluminum material is subjected to an ozone surface treatment with an ozone-containing gas, and a contact angle of 30 °. to form the following hydrophilic film, then forming a silicon oxide-containing film on the surface of the hydrophilic film, an aluminum coating material and forming the coating film on the silicon oxide-containing film It is a manufacturing method.

  In the present invention, examples of the aluminum material to be used include a rolled material made of aluminum or an aluminum alloy, an extruded shape material, a die cast material, a casting material, and a processed material obtained by appropriately processing these materials.

  Further, the hydrophilic film formed by subjecting the surface of the aluminum material to ozone surface treatment with an ozone-containing gas needs to have at least a contact angle of 30 ° or less, preferably 20 ° or less, more preferably 10 It should be hydrophilic below ° C. When the hydrophilicity of the hydrophilic film is higher than the contact angle of 30 °, the adhesion of the coating film is lowered, and as a result, the desired corrosion resistance cannot be exhibited, and when the contact angle is 10 ° or less, the hydrophilicity is increased. The advantage is that the film becomes dense and durability is improved.

  Further, the hydrophilic film should have a film thickness of 1 nm or more, preferably 2 nm or more, more preferably 3 nm or more. If the film is smaller than 1 nm, it becomes difficult to achieve a contact angle of 30 ° or less. The adhesiveness of is reduced.

  The ozone surface treatment for forming a hydrophilic film on the surface of the aluminum material is usually performed at an ozone concentration of 1 vol% to 50 vol%, preferably 1 vol% to 30 vol%, and a treatment temperature of 10 ° C to 300 ° C, preferably 20 ° C or more. It is performed at 200 ° C. or lower. In this ozone surface treatment, if the ozone concentration is less than 1 vol%, it takes too much time to form a hydrophilic film on the surface of the aluminum material, resulting in a decrease in productivity. Conversely, if the ozone concentration exceeds 50 vol%, the effect is saturated. In other words, the manufacturing cost increases. On the other hand, when the treatment temperature is lower than 10 ° C., it takes too much time to form the hydrophilic film, and the productivity is lowered.

  And about this ozone surface treatment, before and / or after the ozone surface treatment, an ozone water cleaning treatment using ozone water or an ultraviolet irradiation treatment using ultraviolet rays may be performed. By using the treatment in combination, a necessary hydrophilic film can be formed more efficiently and effectively, and the effect of improving the adhesion of the paint can be obtained.

In the present invention, a silicate compound-containing film is formed on the hydrophilic film thus formed on the surface of the aluminum material in order to further improve the corrosion resistance, particularly the corrosion resistance in the cast test. to form a coating on the silicate compound-containing coating.

The silicon oxide-containing film formed on the surface of the hydrophilic film for such a purpose can be formed by applying a treatment liquid containing silicon oxide on the surface of the hydrophilic film. ) The amount is 1 mg / m ² or more and 200 mg / m ² or less, preferably 5 mg / m ² or more and 100 mg / m ² or less. If the amount of silicon (Si) is lower than 1 mg / m ² , a sufficient effect of improving corrosion resistance is obtained. On the contrary, if it exceeds 200 mg / m ^2, there arises a problem that the adhesion to the coating film is lowered. The silicon (Si) content in the silicon oxide-containing film is 30% by mass or more, preferably 35% by mass or more.

  The silicon oxide contained in the treatment liquid for forming such a silicon oxide-containing film is preferably water-dispersible silica, and examples of the water-dispersible silica include colloidal silica and gas phase silica. More preferably colloidal silica. The colloidal silica is not particularly limited. For example, as a spherical colloidal silica, SNOWTEX-C, SNOWTEX-O, SNOWTEX-N, SNOWTEX-S, manufactured by Nissan Chemical Industries, Ltd. There are SNOWTEX-OL, SNOWTEX-XS, SNOWTEX-XL and the like, and as chain colloidal silica, there are SNOWTEX-UP and SNOWTEX-OUP manufactured by Nissan Chemical Industries. Gas phase silica includes Aerosil 130, Aerosil 200, Aerosil 200CF, Aerosil 300, Aerosil 300CF, Aerosil 380, Aerosil MOX80, etc. manufactured by Nippon Aerosil Co., Ltd.

In addition, in the treatment liquid for forming the silicon oxide-containing coating, phosphoric acid is added to the silicon oxide-containing coating in addition to the silicon oxide for the purpose of further improving the corrosion resistance. ) It may be added so that the amount is contained in the range of 1.0 mg / m ^{2 to} 20 mg / m ² , preferably 3.0 mg / m ^{2 to} 15 mg / m ² . If the phosphorus (P) content in this silicon oxide-containing film is lower than 1.0 mg / m ² , sufficient corrosion resistance improvement effect cannot be obtained, and conversely, if it exceeds 20 mg / m ² , the adhesion to the coating film is poor. The problem of deteriorating arises.

  The treatment liquid containing the silicon oxide is preferably an aqueous solution or an alcohol solution, and an inorganic additive, a resin, a surface conditioner, a solvent, or the like may be added as necessary.

  The above-mentioned silicon oxide-containing film can also be formed using a silicate-containing alkaline solution containing a silicate such as sodium metasilicate. Examples of the silicate-containing alkaline solution include, for example, Nippon Paint. Surf Cleaner 53, Surf Cleaner 155, Surf Cleaner SE136, Fine Cleaner 4327 made by Nihon Parkerizing, etc. are dissolved in water and 0.5% by mass or more and 20% by mass or less, preferably 1% by mass or more and 15% by mass or less. And the like prepared as an alkaline solution.

In the present invention, the coating film formed on the silicon oxide-containing coating formed on the surface of the hydrophilic coating is not particularly limited, and various types of coatings can be mentioned. Examples thereof include a polyester-based coating film and a silicon-containing coating film. The coating material for forming such a coating film is not particularly limited. For example, acrylic, polyester, urethane, epoxy, fluorine, acrylic silicone, urethane silicone, acrylic urethane Examples thereof include silica-based paints using silicon-based paints, alkali silicate-based paints, colloidal silica, and the like, titanium oxide-based paints, ceramics-based paints, organic, organic / inorganic hybrid systems, and inorganic systems. This coating film may be a single-layer coating film, or may be a multilayer coating film of two or more layers, and the thickness of the coating film is preferably 1 μm or more and 100 μm or less, more preferably Is 2 μm or more and 50 μm or less.

  Here, the coating material for forming the silicon-containing coating film is not particularly limited as long as a coating film containing Si is formed, but the silicon-containing coating film can be formed by simple coating. Examples include paints made from alkoxysilanes and the like, and paints having silanol groups, such as acrylic silicon paints, urethane silicon paints, acrylic urethane silicon paints, alkali silicate paints, colloidal silica, etc. Examples thereof include silica sol-based paints and ceramic-based paints.

Thus, a coating film is formed on the silicon oxide-containing film formed on the surface of the hydrophilic film formed on the surface of the aluminum material, but the coating method at that time is not particularly limited, Either a pre-coating method or a post-coating method may be used. Specific coating methods for the pre-coating method include a roll coating method, a spray coating method, a dipping method, a bar coating method, an electrostatic coating method, and the like. Also, as a specific coating method for the post-coating method, , Spray coating method, spin coating method, dipping method, electrostatic coating method and the like. Furthermore, drying conditions after coating can also be applied according to the coating conditions. For example, air drying, drying, oven, etc. can be used at room temperature to 300 ° C. for 5 seconds to 24 hours. Is called.

Incidentally, prior to the formation of a coating film providing the silicon oxide-containing coating on the hydrophilic coating, but also not particularly limited with its coating method, as in the case of film formation, pre-coating method and post coating Any of the above may be used, and drying conditions after coating can also be applied according to the coating conditions. For example, using an air blower, a dryer, an oven, or the like, the temperature ranges from room temperature to 300 ° C. for 5 seconds to 1 seconds. Performed on time conditions.

  According to the present invention, a hydrophilic film is formed on the surface of the aluminum material by ozone surface treatment, and the surface of the aluminum material can be made hydrophilic without the need for waste liquid treatment or the use of harmful substances, and water-based paint can be applied. In addition, an aluminum coating material having a coating film excellent in corrosion resistance and adhesion can be provided, and a production method thereof can be provided.

  Further, by forming a silicon oxide-containing film on the surface of the hydrophilic film obtained by the ozone surface treatment, and forming a film on the silicon oxide-containing film, the corrosion resistance, particularly the corrosion resistance in the cast test. Can be further improved.

Hereinafter, preferred embodiments of the present invention will be described specifically based on examples , reference examples, and comparative examples.

[ Reference Examples 1 to 4, Examples 1 to 4, and Comparative Examples 1 to 6]
An aluminum plate (JIS 1100) with a size of 70 mm × 150 mm × 0.8 mm is prepared. For Reference Examples 1 to 4, Examples 1 to 4, and Comparative Example 1, this aluminum plate is placed in a glass ozone treatment container. Then, the ozone-containing oxygen gas with the ozone concentration shown in Table 1 was aerated at a ventilation rate of 1 L / min. And the treatment temperature and treatment time shown in Table 1, and the surface of the aluminum plate was treated with ozone. A hydrophilic film was formed.

Moreover, about Examples 1-4 , after forming the hydrophilic membrane | film | coat on the surface of an aluminum plate by ozone surface treatment, the following silicon oxide containing membrane | film | coats were further formed in the surface of this hydrophilic membrane | film | coat.
That is, in Example 1 , a 2 wt% aqueous solution of a silicate-based alkaline degreasing agent (trade name: Surf Cleaner 155, manufactured by Nippon Paint Co., Ltd.) was used, soaked at 60 ° C. for 30 seconds, washed with water and dried to obtain silicon oxide. A containing film was formed.

In Example 2 , a 5 wt% colloidal silica aqueous solution (Nissan Chemicals product name: Snowtex ST-C) was applied with a bar coater (counter # 3) and dried to form a silicon oxide-containing film. Furthermore, in Example 3 , a 0.5 wt% colloidal silica aqueous solution (trade name manufactured by Nissan Chemical Co., Ltd .: Snowtex ST-C) was applied with a bar coater (counter # 3) and dried to form a silicon oxide-containing film. . Furthermore, in Example 4 , a 2.5 wt% ethyl silicate hydrolyzate (trade name: HAS-1 manufactured by Colcoat Co.) was applied with a bar coater (counter # 3) and dried to form a silicon oxide-containing film. did.

Moreover, about Comparative Examples 2-6, the hydrophilic membrane | film | coat or the hydrophilic surface was formed by methods other than the ozone surface treatment shown below.
In Comparative Example 2 (alkali silicate treatment), a 2 wt% aqueous solution of a silicate-based alkaline degreasing agent (trade name: Surf Cleaner 53, manufactured by Nippon Paint Co., Ltd.) was used, and an aluminum plate was immersed in this solution at 60 ° C. for 1 minute. Thereafter, it was washed with water and dried to form a silicate film as a hydrophilic film.

  In Comparative Example 3 (acid treatment + colloidal silica), an aluminum plate was immersed in a 10 wt% sulfuric acid aqueous solution at 40 ° C. for 5 minutes, washed with water and dried, and then a 5 wt% colloidal silica aqueous solution (trade name, manufactured by Nissan Chemical Co., Ltd.). : Snowtex ST-C) was applied with a bar coater (counter # 5) and dried to form a silicate film as a hydrophilic film.

  In Comparative Example 4 (alkali treatment + ethyl silicate), an aluminum plate was immersed in a 5% by weight aqueous sodium hydroxide solution at 40 ° C. for 3 minutes and then washed with water, and then immersed in a 10% by weight aqueous nitric acid solution at room temperature for 1 minute. After neutralizing, washing with water and drying, 5 wt% ethyl silicate hydrolyzate (trade name: HAS-1 manufactured by Colcoat Co., Ltd.) is applied with a bar coater (count # 5), dried, and silicic acid as a hydrophilic film A film was formed.

In Comparative Example 5 (acid treatment), an aluminum plate was immersed in a 10% by weight sulfuric acid aqueous solution at 40 ° C. for 5 minutes, washed with water and dried to form an acid-treated surface as a hydrophilic film.
In Comparative Example 6 (alkali treatment), an aluminum plate was immersed in a 5% by weight aqueous sodium hydroxide solution at 40 ° C. for 3 minutes, washed with water, and then immersed in a 10% by weight aqueous nitric acid solution at room temperature for 1 minute. It was softened, washed with water and dried to form an alkali-treated surface as a hydrophilic film.

  About the hydrophilic film of the aluminum plate obtained as described above, by using a contact angle meter (Kyowa Interface Chemical Co., Ltd .: CA-A type) and measuring the contact angle of the surface using pure water, The degree of hydrophilicity of this hydrophilic film was examined. In addition, in order to investigate the characteristics of the hydrophilic film, the amount of silicon (Si) in the hydrophilic film was measured by fluorescent X-ray analysis. These results are shown in Table 1.

As apparent from the results shown in Table 1, obtained with the hydrophilic film in Comparative Example 2-6 and the obtained hydrophilic film ozone surface treatment of Reference Examples 1-4 and Examples 1-4, both Although the contact angle showed hydrophilicity of 30 ° or less, silicon was not detected in the hydrophilic film obtained by the ozone surface treatment, whereas in Comparative Examples 2 to 4, silicon was detected, It was found that hydrophilicity was expressed by the film. In Comparative Examples 5 and 6, it is considered that the surface of the aluminum plate was dissolved by acid treatment or alkali treatment and degreased to develop hydrophilicity.

Next, on the hydrophilic film of the obtained aluminum plate of Reference Examples 1 to 4 and Comparative Examples 1 to 6, and on the silicon oxide-containing film of the aluminum plate of Examples 1 to 4 , a polyester system A coating material (trade name: V Knit # 500, manufactured by Dainippon Paint Co., Ltd.) was applied with a bar coater so as to have a film thickness of 10 μm, and baked at 220 ° C. for 5 minutes to prepare an aluminum coating material.

Furthermore, similarly on the hydrophilic film of the aluminum plate of Reference Examples 1 to 4 and Comparative Examples 1 to 6, and on the silicon oxide-containing film of the aluminum plate of Examples 1 to 4 , a silicon-containing paint ( Daicel Chemical Industries trade name: Aquabrid ASi91) was coated with a bar coater to a film thickness of 10 μm and baked and dried at 190 ° C. for 15 minutes to prepare an aluminum coating material.

For the aluminum coating materials of Reference Examples 1 to 4, Examples 1 to 4 and Comparative Examples 1 to 6 obtained as described above, a salt spray test (SST: JIS K5600) for 1000 hours as a corrosion resistance test and Cass test for 48 hours and 120 hours (CASS: JIS Z2371) was carried out to evaluate corrosion resistance, and as an adhesion evaluation after water resistance test, cross-cut adhesion test after boiling water immersion test [boiling water immersion Test: ARS2123 (Aluminum Surface Treatment Technology Research Association Test Standard)] was conducted to evaluate the adhesion of the coating film.

The salt spray test (SST) is evaluated as follows: ○: No corrosion or blistering and no change in appearance of coating film, and ×: Corrosion or blistering is observed, and the coating film is abnormal In addition, the evaluation of the cast test (cast) is as follows: ○: Corrosion area ratio 0.1% or less (rating number 9 or more), Δ: Corrosion area ratio 0.25% (rating number 8), and X: Corrosion The area ratio is 0.5% or more (rating number 7 or less), and the adhesion test (adhesion) after the boiling water immersion test is evaluated by the cross-cut method (JIS K5600). (≦ 5%), Δ: Classification 2 (5-15%), ×: Classification 3 or more (15% ≦).
The results are shown in Table 2.

As is clear from the results shown in Table 2, for the aluminum coating material coated with a polyester-based paint, the aluminum coating material of Reference Examples 1 to 4 in which a hydrophilic film was formed by ozone surface treatment was the salt spray test (SST), The evaluation results of the cast test (cast) for 48 hours and the adhesion test (adhesiveness) were both good. About Examples 1-4, it was (circle) also in the case of a cast test for 120 hours.

  On the other hand, Comparative Example 1 in which good hydrophilicity was not obtained even by ozone surface treatment, Comparative Examples 2 to 4 in which a hydrophilic film (silicate film) was formed by a method other than ozone surface treatment, and About each aluminum coating material of comparative examples 5 and 6 in which a hydrophilic surface was formed by acid treatment or alkali treatment, in all cases of salt spray test (SST), cast test (cass) and adhesion test (adhesion) It was bad (x).

Further, as is apparent from the results shown in Table 2, for the aluminum coating material coated with the silicon-containing paint, the aluminum coating materials of Reference Examples 1 to 4 are also used in the salt spray test (SST) and the cast test (cass test). ) The evaluation results of 48 hours and the adhesion test (adhesion) were both good. About Examples 1-4, it was (circle) also in the case of a cast test for 120 hours.

  On the other hand, in Comparative Example 1, all the tests were bad (x), and in Comparative Example 2, the evaluation result of the salt spray test (SST) was ○, and the evaluation result of the adhesion test (adhesion) However, the cast test (cast) was both bad (x) for 48 hours and 120 hours. As for the evaluation results of Comparative Examples 3 and 4, the evaluation result of the salt spray test (SST) was ○, and the evaluation result of the cast test (cast) 48 hours was Δ, but the cast test 120 hours and the close test (adhesiveness) The evaluation result of) was poor (x). Comparative Examples 5 and 6 were all poor (x) except that the evaluation result of the salt spray test (SST) was ○.

  In addition, in the aluminum coating material coated with a silicon-containing paint, when a hydrophilic film made of a silicate film is formed under the silicon-containing paint, the corrosion resistance and cast test (cas) 48 in the salt spray test (SST) Although the time was good, there was a problem with the corrosion resistance after 120 hours of adhesion test (adhesiveness) and cast test (cass).

The aluminum coating material of the present invention forms a coating film on the surface of the aluminum material via a hydrophilic film and a silicon oxide-containing film, so that the coating film can be used without the need for waste liquid treatment or the use of harmful substances. In addition, according to the method for producing an aluminum coating material of the present invention, the surface of an aluminum material can be made hydrophilic without requiring waste liquid treatment or the use of harmful substances. Application | coating is possible, Furthermore, the aluminum coating material which has a coating film excellent in corrosion resistance and adhesiveness can be manufactured easily.

Claims (6)

An aluminum coating material having a coating film on the surface of an aluminum material made of aluminum or an aluminum alloy, and the coating film includes a hydrophilic film provided on the surface of the aluminum material and silicon oxide formed on the surface of the hydrophilic film. object contained is provided through the film, also the aluminum coating material the hydrophilic coating, the contact angle formed by the ozone surface treatment using an ozone-containing gas, characterized in that more than 30 ° .   The aluminum coating material according to claim 1, wherein the hydrophilic film has a thickness of 1 nm or more. The aluminum coating material according to claim 1 or 2 , wherein the coating film is a silicon-containing coating film. A method for producing an aluminum coating material having a coating film on the surface of an aluminum material made of aluminum or an aluminum alloy, wherein the surface of the aluminum material is subjected to ozone surface treatment with an ozone-containing gas to form a hydrophilic coating having a contact angle of 30 ° or less. formation, and then forming a silicon oxide-containing film on the surface of the hydrophilic film, a manufacturing method of an aluminum coating material and forming the coating film on the silicon oxide-containing coating. The manufacturing method of the aluminum coating material of Claim 4 whose film thickness of a hydrophilic membrane | film | coat is 1 nm or more. The method for producing an aluminum coating material according to claim 4 or 5 , wherein the ozone surface treatment is performed under conditions of an ozone concentration of 1 to 50 vol% and a treatment temperature of 10 to 300 ° C.