JPS6022067B2 - Method for forming film on metal surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an aqueous or alcoholic solution comprising an organosilicon monomer having two or more different reactive groups in its molecule, a so-called silane coupling agent, and a fluorine compound of titanium and/or zirconium. The present invention relates to a surface treatment method in which a mixed aqueous solution is applied to a metal surface and dried to form a film with excellent corrosion resistance and paint adhesion.

In order to improve the corrosion resistance and paint adhesion of metals, chromate treatment or phosphate treatment is generally used.

In the chromate treatment method, the chemical conversion coating has the disadvantage that paint adhesion deteriorates over time, and there are also difficulties in wastewater treatment to prevent chromate pollution.
There are problems such as the danger of chromic acid elution from the chemical conversion coating as a source of secondary official documents. In addition, in the phosphate treatment method, coatings such as zinc phosphate and iron phosphate are usually used, but the zinc phosphate coating is a crystalline coating, and when used as a base for painting, the film Depending on the thickness, there are problems such as the crystalline film being broken during bending or the like. In the case of iron phosphate coatings, they are thinner and less corrosion resistant than zinc phosphate coatings, so post-treatment with chromate or the like is usually performed. The purpose of the present invention is to
This method eliminates the above-mentioned drawbacks and has developed a non-polluting surface treatment.It is a coating drying type that is advantageous for wastewater treatment, etc., and provides a surface treatment method with excellent corrosion resistance and paint adhesion as a base treatment for painting etc. There is a particular thing.

As a result of intensive research into a non-polluting surface treatment method that does not have the above-mentioned drawbacks, the present inventors discovered that an organosilicon monomer (hereinafter abbreviated as a silane coupling agent) having two or more different reactive groups in its molecule. After applying an aqueous solution or an alcohol mixed aqueous solution containing one or more selected from the group of fluorine compounds of titanium and/or zirconium to the metal surface, without washing with water. We discovered that by drying objects, it is possible to form a film with excellent corrosion resistance and paint adhesion.
The present invention has now been completed.

The silane coupling agent, which is one of the components of the present invention, has the property of chemically bonding inorganic and organic materials, and is already widely used as an adhesive for industrial products. When a silane coupling agent is applied to a metal surface to improve adhesion and adhesion with organic materials such as molecular resins and is applied as a metal surface treatment film, it can be used to coat metals such as paints and polymer resins. The adhesion was improved and the treatment effect was observed.

However, the expected effect on improving the corrosion resistance of metal surfaces, which is the main purpose of metal surface treatment, was not observed.
There were drawbacks to its use as a practical metal surface treatment film. In addition, as a known technique using a silane coupling agent in the composition of a metal surface treatment agent, there is
28, JP 51-119338, JP 52-130
444, Samuraiko Showa 55-41711, Samuraiko Showa 55-417
13 Japanese Patent Publication No. 55-41712, etc., and the metal surface treatment liquid in these inventions is a water-removable or water-dispersible polymer resin mixed with phosphate, silica, and oxides such as titanium, zirconium, and molybdenum. However, the present inventors have found that, in addition to improving paint adhesion,
As a result of various studies aimed at increasing and improving corrosion resistance, we have developed an aqueous solution or alcoholic solution of a silane coupling agent without using water-soluble or water-dispersible polymer resins, phosphates, silica, etc. By adding an aqueous solution of water-soluble titanium and/or zirconium fluorine compounds to the metal surface, applying the mixed and dissolved composition solution to the metal surface and then drying it, a film with excellent paint adhesion and corrosion resistance is formed on the surface. I saw what was going to happen and sent it out. The surface treatment liquid of the present invention is extremely stable, so when the treatment liquid is put into practical use, there is no precipitation of components, etc.
We also discovered that this method is highly practical because it allows us to treat metal surfaces continuously and stably on an industrial scale, forming a film with excellent paint adhesion and corrosion resistance on the surface. . Although it is not clear why the corrosion resistance is significantly improved by adding a fluorine compound of titanium and/or zirconium, it is not clear why the corrosion resistance is improved by adding a fluorine compound of titanium and/or zirconium. It is thought that in the process of forming a film of polymeric resin, etc., a physically and chemically stable composite film is formed by the combination of the silane coupling agent component and the *elementary compound of titanium and/or zirconium. Furthermore, it is known that fluorine ions and fluorine compounds dissolve and activate passive films on metal surfaces better than phosphate ions and phosphates in metal surface treatment solutions. It is thought that the fluorine ions and atomic compounds present in the treatment solution react with the metal surface during the film formation process of coating and drying, improving the bond between the metal and the film. Another object of the present invention is to obtain excellent corrosion resistance and coating adhesion as a base treatment for paints and polymer resin coatings with an extremely thin coating of about 10 to 300 mm/cm. The object has also been achieved by the present invention.

The present inventors applied a novel metal surface treatment liquid that does not belong to conventionally known technology, that is, a metal surface treatment liquid whose composition is a silane coupling agent and a fluorine compound of titanium and/or zirconium, to a metal surface. The present invention was completed based on the discovery that by drying, a film having excellent corrosion resistance and paint adhesion can be formed on the surface.

In the present invention, "organosilicon monomers having two or more different reactive groups in the molecule, so-called silane coupling agents," refer to "organosilicon monomers having two or more different reactive groups in the molecule." ) and reactive groups (vinyl group, epoxy group,
It is an organosilicon monomer having a methacrylic group, an amino group, etc. in its molecule, and such compounds include trimethylmethoxysilane, y-aminopropyltriethoxysilane, y-aminopropyltrimethoxysilane, N-3
(aminoethyl)y-aminopropyltrimethoxysilane, N-8(aminoethyl)y-aminopropylmethyldiethoxysilane, pinyltriethoxysilane, vinyltris(8-methoxyethoxy)silane, divinyldimethoxysilane, y-glycidoxy Propyltrimethoxysilane, y-methacryloxif.

Examples include lopyltritoxysilane. Examples of the group of fluorine compounds of titanium and/or zirconium include titanium hydrofluoride, titanium ammonium fluoride, zircon hydrofluoride, zircon ammonium fluoride, and metals, oxides, and water of titanium and/or zirconium. It is also possible to react the oxide, ammonium carbonate salt, and organic compound with hydrofluoric acid to make the fluorine compound of titanium or zirconium solubilized in water and use it. The concentration of the silane cobbling agent in the present invention is 0.5 to 100 m/s,
Preferably, it is 1 to 50 evenings/sleeve.

If it is more than 0.5 mm, the effect of the silane coupling agent will not be recognized, and if it is more than 100 mm, the effect of the silane coupling agent cannot be expected to be improved any further, and furthermore, it is not economical. The concentration of the fluorine compound of titanium and zirconium, which is the second component, is 0.01 to 5 m/s, preferably 0.05 to 1.0 m/s, in terms of titanium and zirconium. Below 0.01 evening/hour, the effect of the titanium and/or zirconium fluorine compound is no longer recognized, and above 5 evening/hour it is not economical.

The ratio of the silane coupling agent to the fluorine compounds of titanium and zirconium is 10 to 200:1 (titanium,
(in terms of zirconium), preferably from 20 to 100:1. In addition, the surface treatment solution of the present invention may optionally contain a solubilizing agent for the chemical component of the silane coupling agent in water;
Methanol, ethanol, plastic as a stabilizer.

Add alcohol such as panol. The materials to be treated in the practice of the present invention include common metals such as copper,
In addition to alloy steel, aluminum and aluminum alloys, zinc and zinc alloys, galvanized and galvanized steel, tin and tin-plated steel, etc., ordinary zinc phosphate or iron phosphate treated steel, zinc phosphate treated lead plated steel,
Examples include phosphate-treated tin-plated steel and chromate-treated galvanized steel.

The film forming method of the present invention is applied to the former metals in order to provide a direct surface treatment effect, that is, the effect of forming a film with excellent corrosion resistance and paint adhesion on the metal surface. However, for the latter phosphate-treated steel materials, chromate-treated steel materials, etc., there is a post-treatment effect on the coatings that have already been treated, that is, an effect that further improves the corrosion resistance and paint adhesion of the coatings. It is applied for the purpose of giving. Application of the surface treatment liquid of the present invention is as follows:
Any conventionally known method can be applied, such as brush coating, spray coating, roll coating, and concentrated coating.

For drying after application of the surface treatment liquid of the present invention, normal drying means can be used, and the drying temperature is 60 to 300q.
Any value within the range o can be selected. Next, examples of the present invention will be shown. Example 1 Treatment liquid composition Steel plates, galvanized steel plates, and aluminum plates were cleaned using a 1% heated aqueous solution of an alkaline degreaser (registered trademark Perco Cleaner 364S, manufactured by Nippon Parkerizing), and then immersed in the above treatment liquid for 5 seconds. Perform roll drawing after the groove, 1
At 20:00, it was dried with warm air for 3 calms.

Apply acrylic paint to the obtained board to be treated,
When the coated plates were subjected to dawn coating at 20 mm for 3 minutes and tested, as shown in Table 1, those treated with the treatment solution of the present invention showed excellent test results in both corrosion resistance and paint adhesion. Examples 2 to 4 A steel plate, a galvanized steel plate, and an aluminum plate were treated under the same conditions as in Example 1 using the treatment solutions having the compositions of Examples 2 to 4 below, and then painted under the same conditions as in Example 1. The coated plates were tested.

Composition of treatment liquid in Example 2 Composition of treatment liquid in Example 3 Composition of treatment liquid in Example 4 Corrosion resistance of products treated with the treatment liquid in Examples 2 to 4
The paint adhesion showed excellent test results as shown in Table 1.

Comparative Examples 1 to 4 Steel plates, galvanized steel materials, and aluminum plates were treated under the same conditions as Example 1 using the treatment solutions having the compositions of Comparative Examples 1 to 4 below, and then painted under the same conditions as Example 1. A test was conducted on this coated board.

Treatment liquid composition of Comparative Example 1 (from the treatment liquid composition of Example 1 excluding titanium ammonium fluoride) Treatment liquid composition of Comparative Example 2 (zircon*hydrohydric acid and titanium fluoride from the treatment liquid composition of Example 2) Treatment solution composition of Comparative Example 3 (excluding hydrogen acid) Treatment solution composition of Comparative Example 3 (excluding titanium chloride ammonium from the treatment solution composition of Example 3) Comparative Example 5 An aluminum plate was cleaned using a 1% heated aqueous solution of an alkaline degreaser (Perco Cleaner 36$ mentioned above) and then treated with a 7% heated aqueous solution of chromate treatment (Bonderite 713). After chemical conversion treatment and washing with water, the plate was coated under the same conditions as in Example 1, and the coated plate was tested.

Table 1 (Note 1) Based on salt water mist test JIS Z-2317, the time until blistering occurs at the cross-cut portion of the coating film is expressed.

(Note 2) Cut 100 gobans into the paint film using the test method described in "Paint Testing Methods" by Eriksen Japan Paint Manufacturers Association, and test the back side of the painted surface with the indentations using an Eriksen tester for 30 minutes. After pushing with the wind, press the saddle tape onto the painted surface of the convex part.

Next, the tape was quickly peeled off from the coated surface, and the number of stitches in which the coating film did not peel off from the stitches was indicated.

(Note 3) After leaving the Goban-Eriksen treated object at 40 pm for 7 days, it was painted, and the test in (Note 2) was conducted on the coated board.

Claims (1)

[Claims] 1. An aqueous solution containing one or more organosilicon monomers having two or more different reactive groups in the molecule and one or more selected from the group of fluorine compounds of titanium and zirconium. Alternatively, a method for forming a film on a metal surface, which comprises applying a mixed aqueous solution of alcohol and water to the metal surface and then drying it.