JPH11100630A - Aluminum or aluminum alloy sheet having white gloss after clear coating, and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum or aluminum alloy sheet having simplified and inexpensive manufacturing process, and having a white gloss after clear coating, and provide its manufacture. SOLUTION: This aluminum sheet has 0.14 to 0.5 μm center line average height of surface roughness Ra in a direction parallel to rolling direction. Moreover, when clear coating is applied to the surface of this aluminum sheet, the reflectivity of the coated surface in a direction parallel to rolling direction is regulated to <=7.5% and also the glossiness of the coated surface in a direction parallel to rolling direction is regulated to <=160. By regulating the reflectivity and glossiness of the coated surface as mentioned above, an appearance having a white gloss can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum or aluminum alloy plate used for vehicles such as automobiles, vehicles, trucks, ships and aircraft, containers for home electric appliances, and building materials such as outer walls and interiors. And an aluminum or aluminum alloy plate exhibiting white gloss after clear coating.

[0002]

2. Description of the Related Art Conventionally, in the fields of transport machines, containers for home electric appliances and building materials, aluminum or aluminum alloy plates coated after forming such as press working, or press working machines after coating. An aluminum or aluminum alloy plate subjected to a forming process is used. Hereinafter, the aluminum or aluminum alloy plate is simply referred to as an aluminum plate. There are various demands for the appearance of such an aluminum plate depending on the demand side and the application. For example, an aluminum plate material capable of obtaining high surface gloss after painting is required.

[0003] The surface gloss of an aluminum plate material is easily affected by the type of coating, the coating method, and the base treatment (chromate treatment) of the coating. Therefore, conventionally, the type of coating, the coating method, the coating surface treatment, etc. are variously selected to adjust the surface gloss suitable for the demand side and the application. Gloss can be improved.

[0004] For example, by forming an anodic oxide film having irregularities of a predetermined size with a predetermined average roughness on the surface of an aluminum plate, high sharpness (glossiness and image clarity) can be obtained after coating. An aluminum plate has been proposed (Japanese Patent Laid-Open No. 6-116785).

[0005] In addition, there is also disclosed an aluminum plate having improved sharpness after painting by appropriately adjusting the maximum roughness of the surface of the aluminum plate and the depth of holes formed in the surface. (JP-A-63-238902).

[0006]

However, according to the method of adjusting the kind of the paint, the coating method and the undercoat treatment of the paint, the manufacturing process becomes complicated, so that the manufacturing time is increased and the manufacturing cost is significantly increased. Problem arises. Further, among aluminum plate materials having high surface gloss, for example, there is a demand for a material having white gloss, but such an aluminum plate has not yet been proposed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a simple manufacturing process and can be manufactured at low cost. The aim is to provide a method.

[0008]

According to the present invention, an aluminum or aluminum alloy sheet having a white gloss after clear coating has a center line average surface roughness Ra in a direction parallel to the rolling direction of 0.14 to 0.5 μm. A certain aluminum or aluminum alloy plate, when the surface is clear-coated, the reflectance in the direction parallel to the rolling direction of the coated surface becomes 7.5% or less, and the gloss in the direction parallel to the rolling direction of the coated surface. It is characterized in that the degree is 160 or less.

In another aluminum or aluminum alloy plate according to the present invention, which exhibits a white gloss after clear coating, has a depth of 1 μm or more and a wrinkle formation density of 5 μm or more in a direction perpendicular to the rolling direction. Is 100
10 to 50 aluminum or aluminum alloy plates per μm ² surface area, and when the surface is clear-coated, the reflectance in the direction parallel to the rolling direction of the coated surface becomes 7.5% or less. The glossiness in a direction parallel to the rolling direction of the painted surface is 160 or less.

[0010] Still another aluminum or aluminum alloy plate according to the present invention, which exhibits a white gloss after clear coating,
The depth is 0.5 μm or more and the diameter is 0.5 μm
An aluminum or aluminum alloy plate in which the density of the concave portions is 10 to 50 per surface area of 10 μm ² , and the reflectance in a direction parallel to the rolling direction of the painted surface when the surface is clear-painted is 7.5% or less, and the glossiness in a direction parallel to the rolling direction of the painted surface is 160 or less.

[0011] Still another aluminum or aluminum alloy plate having a white gloss after clear coating according to the present invention is:
The formation density of wrinkles having a depth of 1 μm or more and a length of 5 μm or more in a direction perpendicular to the rolling direction is 100 μm
10 to 50 per m ² surface area,
The formation density of the recesses having a depth of 0.5 μm or more and a diameter of 0.5 μm or more is 10 μm ² per surface area.
0 to 50 aluminum or aluminum alloy plates, and when the surface is clear-coated, the reflectance in a direction parallel to the rolling direction of the coated surface becomes 7.5% or less, and the reflectance in the rolling direction of the coated surface is reduced. The glossiness in the parallel direction is 160 or less.

[0012] The method for producing an aluminum or aluminum alloy plate having a white gloss after clear coating according to the present invention is performed by using a rolling oil having a viscosity of 5 cSt or more.
It has a rolling step of rolling an aluminum or aluminum alloy base sheet at a rolling speed of 00 (m / min) or more, and when the surface is clear painted, the reflectance in a direction parallel to the rolling direction of the painted surface is 7.5% or less. And an aluminum or aluminum alloy plate having a gloss of 160 or less in a direction parallel to the rolling direction of the painted surface is obtained.

After this rolling step, the etching amount is set at 1.
It is preferable to have a chemical conversion treatment step of 0 (g / m ² ) or more.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of intensive experiments and research conducted by the present inventors to solve the above problems, the center line average surface roughness in the direction parallel to the rolling direction of an aluminum plate (aluminum or aluminum alloy plate) was obtained. By appropriately defining the formation density of wrinkles and recesses on the surface of the Ra or aluminum plate,
It has been found that white gloss can be obtained by adjusting the reflectance and glossiness in a direction parallel to the rolling direction of the painted surface after the clear painting.

Hereinafter, the aluminum or aluminum alloy plate according to the present invention will be further described. First, the center line average surface roughness Ra in a direction parallel to the rolling direction of the aluminum plate or the formation density of wrinkles and recesses having a predetermined size or more formed on the aluminum plate surface will be described.

In the direction parallel to the rolling direction of the aluminum plate
Center line average surface roughness Ra: 0.14 to 0.5 μm
When the center line average surface roughness Ra in the direction parallel to the rolling direction of the m aluminum plate is less than 0.14 μm or 0.5 μm or more, the appearance of the painted surface after clear coating this aluminum plate is It turns gray. Therefore, the center line average surface roughness Ra in a direction parallel to the rolling direction of the aluminum plate is set to 0.14 to 0.5 μm.

The density of formation of wrinkles on the surface of an aluminum plate: 1
When 10 to 50 aluminum base plates are rolled per 00 μm ² to produce an aluminum plate, needle-like wrinkles are formed on the surface of the aluminum plate and extend in a direction perpendicular to the rolling direction. The density of wrinkles formed on the surface of this aluminum plate is 10
If the number is less than 10 or more than 50 per 0 μm ² , the appearance of the painted surface after clear coating this aluminum plate becomes gray. Therefore, the formation density of wrinkles on the aluminum plate surface is set to 10 to 50 per 100 μm ² . Note that the depth is less than 1 μm, or the length in a direction orthogonal to the rolling direction is 5 μm.
For wrinkles that are less than irrespective of the formation density, the appearance of the painted surface is not affected. Therefore, in the present invention, only the wrinkles having a depth of 1 μm or more and a length in a direction perpendicular to the rolling direction of 5 μm or more are taken into consideration, and the formation density thereof is defined.

Density of formation of recesses on the surface of aluminum plate: 1
When the formation density of the concave portions formed on the surface of the aluminum plate per 10 μm ² is less than 10 or more than 50 per 10 μm ² , the coating after clear coating this aluminum plate The appearance of the surface turns gray. Therefore, the formation density of the concave portions on the aluminum plate surface is set to 10 to 50 per 10 μm ² . Regarding the concave portions having a depth of less than 0.5 μm or a diameter of less than 0.5 μm, the appearance of the painted surface is not affected regardless of the formation density. Therefore, in the present invention, only the formation density of the concave portions having a depth of 0.5 μm or more and a diameter of 0.5 μm or more is defined.

In the present invention, the object of the present invention can be achieved even with an aluminum plate in which both wrinkles and concave portions are formed as long as the formation density is within the above range.

Next, the reason for limiting the reflectance and glossiness of the painted surface in the direction parallel to the rolling direction after clear coating the aluminum plate will be described.

Pressure after clear coating of aluminum plate
The reflectance of the painted surface in the direction parallel to the elongation direction: 7.5% or less After the clear coating of the aluminum plate surface, if the reflectance of the painted surface in the direction parallel to the rolling direction exceeds 7.5%, white gloss Can not get. Therefore, after clear coating the surface of the aluminum plate, the reflectance of the coated surface in a direction parallel to the rolling direction is 7.5% or less. In addition,
In the present invention, the reflectance is obtained by irradiating light at an angle of 60 ° with respect to the surface of the aluminum plate, calculating the intensity of the reflected light reflected at an angle of 60 °, and determining the reflected light intensity with respect to the incident light intensity. It is defined as the ratio of

Pressure after clear coating of aluminum plate
6. Glossiness of the painted surface in the direction parallel to the elongation direction: 160 or less If the glossiness of the painted surface in the direction parallel to the rolling direction exceeds 160 after clear painting of the aluminum plate surface, the reflectance of the painted surface is 7. As in the case of exceeding 5%, white gloss cannot be obtained. Therefore, the glossiness of the painted surface in a direction parallel to the rolling direction after clear coating the aluminum plate is set to 160 or less.

Next, a method for manufacturing an aluminum or aluminum alloy sheet according to the present invention will be described.

Rolling speed in rolling an aluminum plate: 1
000 (m / min) or more, viscosity of rolling oil: 5 cSt or more At the time of rolling an aluminum plate, the viscosity of the rolling oil is 5
cSt or more, and the rolling speed is 1000 (m /
Minutes), unevenness such as oil pits or wrinkles extending in a direction perpendicular to the rolling direction is easily generated on the surface of the rolled aluminum sheet, and the center line average surface in a direction parallel to the rolling direction is obtained. The roughness Ra increases.
As a result, irregular reflection on the surface of the aluminum plate increases, and the reflectance and glossiness of the painted surface in a direction parallel to the rolling direction decrease, whereby a white surface gloss can be obtained after clear coating. If the viscosity of the rolling oil is less than 5 cSt or the rolling speed is less than 1000 (m / min), the density of wrinkles or recesses in the aluminum plate after rolling is reduced, and the center in the direction parallel to the rolling direction is reduced. Since the line average surface roughness Ra also becomes small, the appearance of the painted surface after the clear painting becomes gray. Therefore, at the time of rolling the aluminum base sheet, the viscosity of the rolling oil is 5 cSt or more, and the rolling speed is 1000 (m / min) or more.

Etching amount during chemical conversion treatment of rolled plate:
After rolling the aluminum alloy base plate with a rolling oil having a viscosity defined in the present invention of 0 (g / m ² ) or more and a rolling speed, the rolled plate is subjected to an etching amount of 1.0 (g / m ² ) or more. When the chemical conversion treatment is performed, the number of concave portions formed of etching pits having a diameter of about 0.5 to 5 μm formed on the surface of the aluminum plate increases. As a result, when the aluminum plate surface is subjected to clear coating, the degree of whiteness can be further enhanced, and a coated surface having excellent surface gloss can be obtained. The amount of etching during the chemical conversion treatment is 1.0 (g / g).
m ² ), the density of formation of wrinkles or recesses in the aluminum plate after etching decreases, and the center line average surface roughness Ra in a direction parallel to the rolling direction also decreases.
The appearance of the painted surface after clear painting becomes gray. Therefore, when a chemical conversion treatment is performed on the rolled sheet after rolling, it is preferable that the etching amount be 1.0 (g / m ² ) or more.

[0026]

EXAMPLES Examples of the aluminum or aluminum alloy plate exhibiting white gloss after clear coating according to the present invention will be specifically described below in comparison with comparative examples.

First Example First, an aluminum plate was manufactured by rolling an aluminum plate made of JIS 5182 alloy at various rolling speeds using rolling oils having various viscosities. Then, the center line average surface roughness Ra was measured at three places in the direction parallel to the rolling direction of the aluminum plate, and the average values were described in the column of average surface roughness Ra. Next, the surface of the aluminum plate is subjected to clear coating, and the surface is JIS Z874.
According to 1, the reflectance and glossiness of the coated surface were measured, and the appearance of the coated surface was visually evaluated. The reflectance and the glossiness were measured in a direction parallel to the rolling direction of the aluminum plate, and the light was irradiated at an angle of 60 ° with respect to the surface of the aluminum plate. Table 1 below shows the rolling conditions and chemical conversion conditions of this aluminum base sheet, and Table 2 shows the measurement results and evaluation results.

[0028]

[Table 1]

[0029]

[Table 2]

As shown in Tables 1 and 2, Example N
o. 1 to 7, the center line average surface roughness Ra in the direction parallel to the rolling direction of the aluminum plate is within the range specified in the present invention, whereby the painted surface in the direction parallel to the rolling direction after the clear coating. Since the reflectance and glossiness were properly adjusted, a painted surface having white gloss was formed.

On the other hand, in Comparative Example No. 8 to 13, one or both of the viscosity and the rolling speed of the rolling oil are out of the range of the present invention, and the center line average surface roughness Ra in the direction parallel to the rolling direction is from the range specified in the present invention. As a result, the reflectance and glossiness of the coated surface in the direction parallel to the rolling direction after the clear coating exceeded the upper limit of the range of the present invention, and a coated surface having white gloss could not be obtained.

Second Embodiment An aluminum plate was prepared in the same manner as in the first embodiment, and
On the surface of each aluminum plate, the depth is 1 μm or more, and the length in the direction perpendicular to the rolling direction is 5 μm.
The formation density of wrinkles of not less than μm was determined. The length and formation density of the wrinkles are determined by observing the surface of the aluminum plate with a microscope at a magnification of 500 times, measuring the length of the wrinkles in this field of view, and determining the number of wrinkles having a depth and length equal to or more than a predetermined size. Was determined by counting. The wrinkle depth was determined by measuring the profile of the surface shape in three directions parallel to the rolling direction of the aluminum plate using a roughness meter.

Next, the surface of this aluminum plate was subjected to clear coating, the reflectance and gloss of the coated surface were measured in the same manner as in the first embodiment, and the appearance of the coated surface was visually evaluated. Table 3 below shows the measurement results and the evaluation results. In addition, the formation density of wrinkles in Table 3 below indicates that the depth is 1 μm.
m or more, and is a value for only wrinkles whose length in a direction perpendicular to the rolling direction is 5 μm or more.

[0034]

[Table 3]

As shown in Table 3 above, Example No. 21
To 24, the formation density of wrinkles is within the range specified in the present invention, whereby the reflectance and glossiness of the coated surface in the direction parallel to the rolling direction after clear coating are appropriately adjusted, A painted surface having a white gloss was formed.

On the other hand, in Comparative Example No. 25 to 28, the formation density of wrinkles is out of the range specified in the present invention, whereby the reflectance and gloss of the coated surface in the direction parallel to the rolling direction after clear coating are out of the range of the present invention. Therefore, a painted surface having white gloss could not be obtained.

Third Embodiment An aluminum plate was rolled in the same manner as in the first embodiment, and the rolled plate was subjected to a chemical conversion treatment with various etching amounts to produce an aluminum plate. Then, on the surface of each aluminum plate, the depth is 0.5 μm.
m or more, and the formation density of the concave portion having a diameter of 0.5 μm or more was determined. The formation density of the concave portions was determined by observing the surface of the aluminum plate with a microscope at a magnification of 5000 times and counting the number of concave portions having a depth and a diameter equal to or more than a predetermined size in this visual field region. The depth and diameter of the concave portion were determined by measuring the profile of the surface shape in three directions parallel to the rolling direction of the aluminum plate using a roughness meter.

Next, the surface of this aluminum plate was subjected to clear coating, the reflectance and glossiness of the coated surface were measured in the same manner as in the first embodiment, and the appearance of the coated surface was visually evaluated. Table 4 below shows the measurement results and the evaluation results. The formation density of the concave portions in Table 4 below is such that the depth is 0.
The value is only for concave portions having a diameter of 5 μm or more and a diameter of 0.5 μm or more.

[0039]

[Table 4]

As shown in Table 4 above, Example No. 31
To 34, the formation density of the concave portions is within the range specified in the present invention, and since the reflectance and glossiness of the coated surface in the direction parallel to the rolling direction after clear coating are appropriately adjusted, A painted surface having a white gloss was formed.

On the other hand, in Comparative Example No. 35 to 38, the formation density of the concave portions is out of the range specified in the present invention, whereby the reflectance and gloss of the coated surface in the direction parallel to the rolling direction after clear coating are out of the range of the present invention. Therefore, a painted surface having white gloss could not be obtained.

Fourth Embodiment An aluminum plate is manufactured in the same manner as in the third embodiment.
In the same manner as in the second embodiment, the formation density of wrinkles formed on the surface of each aluminum plate is determined, and in the same manner as in the third embodiment, the formation density of recesses formed on the surface of each aluminum plate. I asked.

Next, the surface of this aluminum plate was subjected to clear coating, the reflectance and glossiness of the coated surface were measured in the same manner as in the first embodiment, and the appearance of the coated surface was visually evaluated. Table 5 below shows the measurement results and the evaluation results. In addition, the formation density of wrinkles and the formation density of concave portions in Table 5 below are values for only wrinkles and concave portions whose depth, length, and diameter are equal to or more than predetermined values.

[0044]

[Table 5]

As shown in Table 5 above, Example No. 41
In Nos. To 42, the formation density of wrinkles and the formation density of concave portions are within the ranges specified in the present invention, whereby the reflectance and gloss of the coated surface in the direction parallel to the rolling direction after clear coating are appropriately adjusted. Thus, a painted surface having white gloss was formed.

On the other hand, in Comparative Example No. In Nos. 43 to 46, the formation density of wrinkles and the formation density of concave portions are out of the ranges specified in the present invention, whereby the reflectance and glossiness of the coated surface in the direction parallel to the rolling direction after clear coating are reduced. Since it was out of the range of the invention, a painted surface having white gloss could not be obtained.

[0047]

As described in detail above, according to the present invention,
Center line average surface roughness R in the direction parallel to the rolling direction
a, the formation density of wrinkles or recesses is appropriately defined, thereby adjusting the reflectance and glossiness of the coated surface in a direction parallel to the rolling direction after the clear coating, so that after the clear coating, white A glossy painted surface can be obtained. Further, according to the method of the present invention, since the rolling speed and the viscosity of the rolling oil used during the rolling of aluminum or an aluminum base plate are appropriately specified, the reflection of the painted surface in a direction parallel to the rolling direction after the clear coating is performed. The rate and gloss can be adjusted, and an aluminum or aluminum alloy plate exhibiting white gloss after clear coating can be manufactured. At the time of this rolling, when the etching amount is appropriately defined, the degree of whiteness of the clear painted surface can be further increased, and a painted surface having excellent surface gloss can be obtained.

Claims (6)

[Claims] 1. An aluminum or aluminum alloy plate having a center line average surface roughness Ra of 0.14 to 0.5 μm in a direction parallel to a rolling direction, wherein when the surface is subjected to clear coating, the rolling direction of the coated surface is increased. Aluminum or an aluminum alloy exhibiting white gloss after clear coating, wherein the reflectance in a direction parallel to the direction of rolling is 7.5% or less and the glossiness of the coated surface in the direction parallel to the rolling direction is 160 or less. Board. ^2. An aluminum or aluminum alloy having a depth of 1 μm or more and a wrinkle formation density of 10 to 50 per 100 μm ² of surface area having a length of 5 μm or more in a direction perpendicular to the rolling direction per 100 μm ^2. When the surface is clear-coated, the reflectance in the direction parallel to the rolling direction of the coated surface is 7.5% or less and the glossiness in the direction parallel to the rolling direction of the coated surface is 1
An aluminum or aluminum alloy plate having a white gloss after clear coating, wherein the thickness is 60 or less. 3. The formation density of a concave portion having a depth of 0.5 μm or more and a diameter of 0.5 μm or more is 10 μm ^2.
10 to 50 aluminum or aluminum alloy plates per surface area, and when the surface is clear-painted, the reflectance in the direction parallel to the rolling direction of the painted surface becomes 7.5% or less, and An aluminum or aluminum alloy plate exhibiting white gloss after clear coating, wherein the gloss in a direction parallel to the rolling direction of the surface is 160 or less. 4. The formation density of wrinkles having a depth of 1 μm or more and a length of 5 μm or more in a direction perpendicular to the rolling direction is 10 to 50 per 100 μm ² surface area, and the depth is An aluminum or aluminum alloy plate having a density of not less than 0.5 μm and having a diameter of not less than 0.5 μm and having a formation density of concave portions of 10 to 50 per 10 μm ² surface area. The film has a reflectance of 7.5% or less in a direction parallel to the rolling direction of the surface and a gloss of 160 or less in a direction parallel to the rolling direction of the painted surface, and exhibits white gloss after clear coating. Aluminum or aluminum alloy plate. 5. A rolling step of rolling an aluminum or aluminum alloy raw sheet at a rolling speed of 1000 (m / min) or more using a rolling oil having a viscosity of 5 cSt or more, and The reflectance in the direction parallel to the rolling direction of the painted surface becomes 7.5% or less,
The glossiness in the direction parallel to the rolling direction of the painted surface is 160
A method for producing an aluminum or aluminum alloy plate exhibiting white gloss after clear coating, characterized by obtaining an aluminum or aluminum alloy plate as described below. 6. The aluminum exhibiting white luster after clear coating according to claim 5, further comprising, after the rolling step, a chemical conversion treatment step in which an etching amount is 1.0 (g / m ² ) or more. Or a method of manufacturing an aluminum alloy plate.