JP2637580B2 - High quality 3C1B coating method - Google Patents

Description

The present invention relates to a high quality 3C1B coating method. More specifically, the present invention relates to a high-quality 3C1B coating method for simultaneously baking a middle coat and a 2C1B type top coat.

 Here, 3C1B means three coatings and one baking.

[Prior art] Conventionally, for the purpose of improving rust prevention quality,
Cationic electrodeposition is widely used instead of anionic electrodeposition. However, since the cationic electrodeposition coating film is more significantly deteriorated by ultraviolet rays than the anion electrodeposition coating film, an intermediate coating film is indispensable. That is, for example, the cationic electrodeposition coating film is easily deteriorated by light having a wavelength in the ultraviolet region that enters through the metallic overcoat film, and the cationic electrodeposition alone has a high degradability, so that an intermediate coating is always required. is there. The middle coat has a large amount of pigment components and can cut off ultraviolet rays, and this is the constitution principle of the cationic-medium coat-metallic top coat.

According to this principle, (1) intermediate coating → baking, then 2C1B type metallic coating → baking (3C2B) on the electrodeposition coating film, and (2) intermediate coating and 2C1B type metallic coating → simultaneous There are two ways of printing (3C1B).

Compared to the former, which requires two baking, the baking step is omitted once and the economic effect is large, but the normal baking reduces the smoothness and sharpness of the coating film, and the There was a defect that was lacking.

[Problems to be Solved by the Invention] The present invention has been made in view of the problems in the above-mentioned conventional 3C1B coating method. An object of the present invention is to provide a high quality 3C1B coating method which enables simultaneous baking of an intermediate coating film-2C1B type metallic topcoat film without lowering the coating property.

[Means for Solving the Problems] As a result of extensively examining steel plates and paints in order to achieve high quality coating with 3C1B, the present invention has been reached.

The present invention has a patterned area ratio of 50-60%
The depth of the irregularities generated by the patterning is about 4 to
A 6 μm laser dull steel plate is primed by cationic electrodeposition coating and baked, and then the intermediate coat, all of the top coat base and top coat clear, or at least one of them, is coated with a non-aqueous dispersion paint, The present invention relates to a high quality 3C1B coating method characterized by baking.

That is, they have found that a high-quality coating film can be obtained for the first time by a coating characterized by a combination of a non-aqueous dispersion coating (hereinafter, referred to as NAD coating) and a laser dull steel plate.

[Example] The laser dull steel plate used in the present invention is a roll which is patterned with a laser at the time of manufacturing the steel plate. The ratio of the area patterned by the roll to the entire surface of the steel plate is, for example, 45 to 65%. is there. The ratio is calculated by calculating the area of the pattern portion in the rectangle with respect to the area of the rectangle formed by connecting the centers of four adjacent patterns. Further, the depth of the unevenness generated by patterning has, for example, 1 to 10 μm, and there is a great difference between the conventional dull steel plate and the unevenness pattern. Conventionally, laser dull steel sheets are said to provide high definition.However, if only 3C1B coating is used, such results cannot always be obtained. The cinematography is obtained. In particular, the laser dull steel sheet has a patterned area ratio of 50-60%
The depth of the irregularities generated by the patterning is about 4 to
Those having 6 μm, especially about 5 μm, are good.

The NAD paint is an emulsion type using hexane or the like as a solvent. As other types of paints, melt-type paints are often used, but high quality cannot be obtained with such paints.

Although it is not clear why the combination of NAD paint and laser dull steel plate gives the high quality of 3C1B paint system for the first time,
It is presumed that this is synergistically caused by the quick drying property of the NAD paint and the effect of imparting high sharpness to the laser dull steel sheet.

By the way, for example, a painted surface of an automobile or the like has a structure in which, even if the object to be painted is held at any angle or rotated continuously or intermittently, the painted surface is always substantially horizontal and substantially vertical. A painted surface occurs. Such painting and baking of automobile bodies require high quality for both horizontal and vertical parts, so even if the quality of only the horizontal part or only the vertical part is improved, high quality is not achieved, Both parts and vertical parts are required to be improved or equivalent to the conventional 3C2B coating.

Example 1 Cationic electrodeposition coating (film thickness: 20 μm) and baking (170 ° C.)
/ 20 min) laser dull steel plate (Kawasaki Steel Corporation)
NAD paint (DN-05, manufactured by Kansai Paint Co., Ltd.) as base A (middle coat) (film thickness: 15 μm), and NAD paint (DN-05, Kansai Paint (base coat)) as base B (top coat) Co., Ltd.) was applied (film thickness 15 μm), and NAD paint (DN-10u, manufactured by Kansai Paint Co., Ltd.) was applied as a clear (top coat) (film thickness 25 μm), and then baked (140).
° C / 20 min).

Example 2 A sample of Example 2 was obtained in the same manner as in Example 1 except that a dissolvable intermediate coating (DA-16, manufactured by Kansai Paint Co., Ltd.) was used as the base A (film thickness: 15 μm).

Example 3 Dissolvable paint (DA-16, manufactured by Kansai Paint Co., Ltd.) was used as base A (DA-16, manufactured by Kansai Paint Co., Ltd.) (film thickness: 15 μm). A sample of Example 3 was obtained in the same manner as in Example 1 except that the thickness was 15 μm.

Comparative Example 1 A common dissolvable paint (DA-16, manufactured by Kansai Paint Co., Ltd.) was used as base A (film thickness: 15 μm), and a dissolvable paint (DA-16, manufactured by Kansai Paint Co., Ltd.) was used as base B. (15 μm thick) and bake (14
A sample of Comparative Example 1 was obtained in the same manner as in Example 1 except that (0 ° C./20 minutes).

Comparative Example 2 A sample of Comparative Example 2 was obtained in the same manner as in Example 1 except that a conventional dull steel plate (Ra defined by JIS B 0601 was 1.0) was used.

Comparative Example 3 Example 2 except that a conventional dull steel plate (Ra: 1.0) was used.
In the same manner, a sample of Comparative Example 3 was obtained.

Comparative Example 4 A sample of Comparative Example 4 was obtained in the same manner as in Example 3 except that a conventional dull steel plate (Ra: 1.0) was used.

Comparative Example 5 A sample of Comparative Example 5 was obtained in the same manner as in Comparative Example 1, except that a conventional dull steel plate (Ra: 1.0) was used.

The resulting sample was evaluated for sharpness and smoothness.

The sharpness was measured using a commercially available sharpness gloss meter (PGd meter). The results are shown in Table 1 as an average of the measured values for the five coated plates.

In addition, the measurement of the smoothness was performed in comparison with a previously prepared smoothness reference plate (a plate having a larger numerical value in order from a plate having better smoothness). The results are represented by values of a reference plate having the same smoothness, and the first value is an average value of five painted plates.
It is shown in the table.

From Table 1, the samples of Examples 1 to 3 are comparative examples 2 to 3.
Compared to Comparative Example 1 and Comparative Example 5 in which printing is performed twice, it has better clarity and smoothness on both the horizontal plane and the vertical plane than that of Comparative Example 1, and has a high height equivalent to them. It can be seen that a quality coating film was obtained.

[Effects of the Invention] According to the method of the present invention, it is possible for the first time to simultaneously bake an intermediate coating film-2C1B type metallic overcoating film without deteriorating the smoothness and sharpness of the coating film, and a high quality 3C1B coating film is obtained. Is achieved.

Claims (1)

(57) [Claims] 1. The patterned area ratio is 50-60%
The depth of the irregularities generated by the patterning is about 4 to
A 6 μm laser dull steel plate is primed by cationic electrodeposition coating and baked, and then the intermediate coat, all of the top coat base and top coat clear, or at least one of them, is coated with a non-aqueous dispersion paint, High quality 3C1B coating method characterized by baking.