JPS6211061B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD This invention relates to a fluororesin-coated aluminum alloy plate in which at least one of both surfaces is coated with a fluororesin. In this specification, "%" indicates "% by weight". Prior Art and Its Problems Fluororesin has excellent chemical resistance, water resistance, oil resistance, heat resistance, etc., and is used by coating various products that require these properties. Such products are made by molding a fluororesin-coated aluminum alloy plate. Conventionally, the above-mentioned fluororesin-coated aluminum alloy sheets have been prepared by applying a surface treatment to at least one of both sides of an aluminum alloy sheet made of A3004 alloy or a commercially available Al--Mg--Mn alloy. The surface treated with this base is coated with a fluororesin coating. The above-mentioned surface treatment includes sandblasting,
This has been done by a primer coating method, chemical or electrochemical etching method, etc. However, the sandblasting method has a problem in that the resulting unevenness is rough and the adhesion between the fluororesin coating film and the substrate is poor. According to the primer coating method, there is a problem in that the adhesion between the fluororesin coating film and the substrate deteriorates due to moisture, moisture, and the like. In addition, the etching method can solve the above-mentioned problems in the sandblasting method and primer coating method, but
When conventionally used aluminum alloys such as A3004 alloy are used as substrates, the adhesion between the fluororesin coating and the substrate is still insufficient, and products made from this alloy plate are There was a risk that the coating film and the alloy plate would peel off. This invention has been made in view of the above circumstances, and provides a fluororesin-coated aluminum alloy plate that has greater adhesion between an aluminum alloy plate serving as a substrate and a fluororesin coating than conventional ones. The purpose is to Means for Solving the Problems One fluororesin-coated aluminum alloy plate of the present invention contains 0.5 to 3% iron and silicon as an impurity.
0.15% or less each of copper and manganese as impurities
At least one of both surfaces of an aluminum alloy plate containing 0.1% or less and the balance being aluminum is made into a rough surface with a distance between ridges and valleys of 5 to 50 μ and fine irregularities, and this rough surface is made of fluorine. Another fluororesin-coated aluminum alloy plate of the present invention is coated with a resin coating film.
At least one of both sides of an aluminum alloy plate containing 0.5-3% magnesium, 0.3-3% magnesium, 0.15% or less silicon as an impurity, 0.1% each copper and manganese as impurities, and the balance aluminum. The distance between the ridges and the valleys is 5 to 50 microns, and the rough surface has fine irregularities, and this rough surface is coated with a fluororesin coating film. In the above, the aluminum alloy plate to be coated with fluororesin is an aluminum alloy plate containing 0.5 to 3% iron, 0.15% or less silicon as impurities, 0.1% each copper and manganese as impurities, and the balance aluminum. The reason is as follows. In other words, chemical or electrochemical etching is preferable as the base treatment applied to the aluminum alloy plate, which is the substrate to which the fluororesin is usually coated, as described above. In order to improve the adhesion between the coated aluminum alloy plate and the fluororesin, when the aluminum alloy plate to be coated with the fluororesin is etched, conditions (a)... The distance must be within the range of 5 to 50μ. Condition (b)...The rough surface form due to etching becomes minute irregularities. Condition (c): Etching is almost uniform. It is necessary to satisfy all three conditions. This is because if the distance between the peaks and valleys in the unevenness caused by etching is less than 5 μm, the above-mentioned adhesion will be poor, and if it exceeds 50 μm, a large amount of fluororesin will be required. In addition, if the rough surface formed by etching does not become fine irregularities, the adhesion will be poor. Furthermore, if the etching is uneven, protrusions that protrude from the average height (referring to the height of the protrusions that are almost uniform among the protrusions with height differences caused by etching) will occur.
If fluororesin is painted on top of it, the adhesion between the fluororesin and the aluminum alloy plate will be poor, and convex parts exceeding the average height will be exposed from the resin coating, and the resin coating will be thin locally. As a result, pinholes occur after the resin coating is formed, which impairs the smoothness of the resin coating surface, and the aluminum alloy plate comes into direct contact with water, steam, oil, and chemicals, resulting in poor corrosion resistance. If it's bad, it's because it's bad. As an aluminum alloy plate to be coated with fluororesin, 0.5 to 3% iron and 0.15 silicon as impurities.
% or less, copper and manganese as impurities each 0.1
The reason why an aluminum alloy plate is used is that the aluminum alloy plate satisfies all three conditions (a) to (c) above and has excellent etching properties. In the above, iron is contained in aluminum, so that when the aluminum alloy plate to be coated with fluororesin is subjected to ordinary chemical etching or electrochemical etching, the alloy plate meets the above conditions (a) ( It has properties that allow it to satisfy all of b) and (c). The reason for this is not clear, but iron is potentially more noble than aluminum, and
Since it has a wide range of solid solubility in aluminum, when it is included in aluminum, chemical or electrochemical etching is performed so that the alloy plate satisfies the above conditions (a), (b), and (c). It is thought that this is the case. However, if the content is less than 0.5%, the above-mentioned alloy plate will not satisfy conditions (a), (b), and (c), and the crystal grains will become coarse, and an etching pattern will appear when etched, resulting in loss of commercial value. If it exceeds, coarse crystallized substances will occur and the alloy plate will no longer satisfy conditions (a), (b), and (c). Therefore, the iron content should be selected within the range of 0.5 to 3%, with around 1% being particularly preferred. Silicon, copper and manganese are contained as impurities in aluminum and have a negative effect on the properties of this type of alloy, and the silicon content is 0.15%.
If this value is exceeded, the alloy plate will no longer satisfy conditions (a), (b), and (c), and the edge height will become high when the alloy plate is formed by deep drawing after being coated with fluororesin. If the copper content exceeds 0.1%, the corrosion resistance of the alloy plate will deteriorate. If the manganese content exceeds 0.1%, the alloy plate will no longer satisfy condition (c) and the surface will become rough. Therefore, the content of these impurities should be below 0.15% silicon, below 0.1% copper and below 0.1% manganese. In addition, as an aluminum alloy plate to be coated with fluororesin, iron 0.5-3%, magnesium 0.3-3%
%, silicon as an impurity of 0.15% or less, copper and manganese as impurities of 0.1% or less each, and the balance is aluminum, satisfying the above three conditions (a), (b), and (c). Moreover, after painting this aluminum alloy plate with fluorocarbon resin,
Even when this fluororesin-coated aluminum alloy plate is molded, it is possible to obtain a fluororesin-coated aluminum alloy plate that can minimize the decrease in adhesion between the aluminum alloy plate serving as a substrate and the fluororesin coating film. can. This is because if the strength of the aluminum alloy plate is low, if it is molded after being coated with a fluororesin, the amount of deformation will increase and the adhesion with the fluororesin coating will decrease. The above magnesium content is 0.3
The reason for limiting the range to ~3% is that if it is less than 0.3%, the effect of increasing the strength of the aluminum alloy plate will not be sufficiently obtained, and if it exceeds 3%, the distance between the peaks and valleys of the unevenness caused by etching will be reduced. is too small to satisfy the above condition (a), and the strength becomes too large, resulting in poor moldability. Therefore, the magnesium content is
It should be selected within the range of 0.3 to 3%. There are various conventional chemical etching methods and electrochemical etching methods that can be applied to the aluminum alloy plate, and examples of the chemical etching method include immersion in an aqueous hydrochloric acid solution. Further, as an electrochemical etching method, for example, there is a method of anodic treatment using a direct current in an aqueous solution containing an electrolyte made of chloride. The coating of fluororesin on the roughened aluminum alloy plate by etching is carried out by a conventional method. Furthermore, the coating of fluororesin may be performed immediately after etching treatment, or after surface treatment such as chemical conversion treatment or anodization treatment is applied to the roughened area after etching treatment. good. Embodiments Examples of the present invention will be described below with reference to the drawings. In the fluororesin-coated aluminum alloy plate 1 according to the present invention, one side of the aluminum alloy plate 2 is a rough surface having a distance H between peaks and valleys of 5 to 50μ and fine irregularities 3, and this surface is made of fluorine resin. It is coated with a resin coating film 4. The aluminum alloy plate 2 contains 0.5 to 3% iron and silicon as an impurity.
0.15% or less each of copper and manganese as impurities
An aluminum alloy containing 0.1% or less of magnesium with the balance being aluminum, or an aluminum alloy containing 0.3 to 3% of magnesium in this aluminum alloy. Next, the results of an evaluation test conducted on the fluororesin-coated aluminum alloy plate of the present invention and a comparative product will be shown. Alloy A: Iron 0.74%, Silicon 0.09%, Manganese 0.01
% and 0.01% or less of copper, with the balance being aluminum. Alloy B: 0.74% iron, 0.7% magnesium, silicon
An aluminum alloy containing 0.09% manganese, 0.01% manganese and 0.01% or less copper, with the balance being aluminum. Alloy C 0.74% iron, 1.3% magnesium, silicon
An aluminum alloy containing 0.09% manganese, 0.01% manganese and 0.01% or less copper, with the balance being aluminum. Alloy D A3004. Alloy E Al--Mg--Mn based alloy (commercial product) The five types of aluminum alloys mentioned above were formed into a plate with a thickness of 1.5 mm by a conventional manufacturing method, and then annealed. Next, after applying chemical etching as usual, i.e. 15%
The tensile strength and peeling strength before and after molding of the fluororesin-coated aluminum alloy plate obtained by immersing it in a hydrochloric acid aqueous solution for 7 minutes and then coating it with fluororesin to a thickness of 35 μm (fluororesin coating film (representing the adhesion force to the alloy plate) was measured. The results obtained are shown in the table below.

[Table] As is clear from the above table, the fluororesin-coated aluminum alloy plate according to the present invention has extremely high adhesion between the aluminum alloy plate and the fluororesin coating film compared to the conventional one. In particular, in the fluororesin-coated aluminum alloy plate according to the second aspect of the invention, the adhesion between the aluminum alloy plate and the fluororesin coating film decreases little after forming. Effects of the Invention As described above, the fluororesin-coated aluminum alloy plate according to the present invention is an aluminum alloy plate containing 0.5 to 3% iron, 0.15% or less silicon as impurities, 0.1% or less each of copper and manganese as impurities, and the balance being aluminum. At least one of both sides of the alloy plate is a rough surface with a distance between peaks and valleys of 5 to 50μ and minute irregularities, and this rough surface is coated with a fluororesin coating film. Therefore, it is possible to obtain a fluororesin-coated aluminum alloy plate in which the adhesion between the aluminum alloy plate and the fluororesin coating film is large. In particular, in the second invention, as an aluminum alloy plate to be coated with a fluororesin, the aluminum alloy plate to be coated with a fluorine resin in the first invention further contains magnesium within a range of 0.3 to 3%. The strength of this alloy plate is improved, and the amount of deformation when forming the fluororesin-coated aluminum alloy plate is reduced. Decrease in adhesion to the paint film can be kept to a minimum.

[Brief explanation of the drawing]

The drawings are cross-sectional views showing embodiments of the invention. 1... Fluorine resin coated aluminum alloy plate, 2
...Aluminum alloy plate, 3...Irregularities, 4...Fluorine resin coating film.

Claims (1)

[Claims] 1. 0.5-3% iron, 0.15% silicon as an impurity.
Below, 0.1% each of copper and manganese as impurities
At least one of both sides of an aluminum alloy plate containing the following and the remainder being aluminum is made into a rough surface with a distance between crests and valleys of 5 to 50μ and fine irregularities, and this rough surface is coated with fluororesin. Fluorine resin-coated aluminum alloy plate coated with a film. 2 At least one of both sides of an aluminum alloy plate containing 0.5 to 3% iron, 0.3 to 3% magnesium, 0.15% or less silicon as impurities, 0.1% or less each of copper and manganese as impurities, and the balance aluminum, The distance between the peak and valley is 5 to 50μ
A fluororesin-coated aluminum alloy plate that has a rough surface with large and fine irregularities and is coated with a fluororesin coating.