如何测定彩涂板基板脱脂后的清洁度

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彩涂板清洁度的测定方法有两种：实验室仪器法和生产现场简易法。仪器方法包括电子显微镜、激光散射和表面分析。这些方法主要用于对彩涂板基材清洁度和涂层力学性能要求较高的情况，但这些方法受到许多客观的限制。目前，它们大多仍在实验室研究范围内。在彩涂板的生产和应用中，基板的清洁度主要由以下方法决定。
（1）擦拭方法。用干净的白色非毛布（如纱布）、棉花和滤纸擦拭带钢表面，然后观察布、棉花和滤纸上的污垢程度，以判断带钢表面的清洁度。这种方法简单，但不够准确。
（2）液滴法。它是用接触角来评价清洁度的一种方法。在一定条件下，表面液滴直径（一定体积）越大，接触角越小，清洁度越高。也就是说，表面形成的水滴的直径和形状是清洁的基础。
（3）渗透法。干净的金属表面是亲水的，所以它们可以被水完全润湿。当在钢带表面处理污垢或油块时，会有一个不被水润湿的“失水区”。但是由于金属氧化物膜也是亲水性的，所以润湿方法不能检测氧化膜是否可以被去除。
（4）呼气。脱脂干燥后，在试样表面呼气。如果表面清洁，就会形成均匀连续的雾水形状。清洁度高时，雾斑均匀，但油腻处无雾水。当表面非常光滑和干净时，雾斑会在很短的时间内消失。
（5）断水方法。将清洗后的试样浸入水中，使试样垂直于水面，然后移出水面。倾斜45度离开水面后，观察样品表面是否有水滴或无水区。如果钢带表面有污垢，如果在试样表面形成的水膜能均匀地覆盖所有表面，则说明。高度清洁。

（6）跌落试验方法。参照cb/1332-19，在试样表面滴入2滴标准g型极性溶液（约0.ml）。20毫米×40毫米的覆盖面积立即涂上玻璃棒。将特种A型油纸贴附在溶液膜上，1分钟后观察到黄色。a型油试纸颜色均匀、连续、完整，清洁度高，反之不合格。

There are two methods to determine the cleanliness of color coated sheets: laboratory instrument method and production site simple method. Instrumentation methods include electron microscopy, laser scattering and surface analysis. These methods are mainly used in the case of high requirements for cleanliness of color coated plate substrate and mechanical properties of coatings, but these methods are subject to many objective restrictions. At present, most of them remain in the scope of laboratory research. In the production and application of color coated sheets, the cleanliness of the substrate is mainly determined by the following methods.
(1) Wiping method. Wipe the surface of the strip with clean, white, non-wool cloth (such as gauze), cotton and filter paper, and then observe the degree of dirt on the cloth, cotton and filter paper to judge the cleanliness of the surface of the strip. This method is simple but not accurate enough.
(2) Droplet method. It is an application of contact angle to evaluate cleanliness. Under certain conditions, the larger the diameter of the droplet (a certain volume) on the surface, the smaller the contact angle and the higher the cleanliness. That is to say, the diameter and shape of water droplets formed on the surface are taken as the basis of cleanliness.
(3) infiltration method. Clean metal surfaces are hydrophilic, so they can be completely wetted by water. When dirt or oil blocks are treated on the surface of steel strips, there will be a "water loss zone" that will not be wetted by water. But because the metal oxide film is also hydrophilic, the wetting method can not detect whether the oxide film can be removed.
(4) Exhalation. After degreasing and drying, exhale on the surface of strip sample. If the surface is clean, it will form a uniform and continuous fog-water shape. When the cleanliness is high, the fog spots are uniform, but there is no fog water in the greasy areas. When the surface is very smooth and clean, the fog spots will disappear in a very short time.
(5) Water cut-off method. Immerse the cleaned sample in water, make the sample vertical to the water surface, then move out of the water surface. Observe whether there is a water drop or no water area on the surface of the sample after leaving the water surface from an inclined angle of 45. If there is dirt on the surface of the steel strip, if the water film formed on the surface of the sample can evenly cover all the surfaces, then explain. High cleanliness.
(6) Drop test method. Referring to CB/1332-19, two drops of standard G-type polar solution (about 0.mL) were applied on the surface of the tested specimen. The covered area of 20 mm *40 mm was immediately coated with glass rod. The special type A oil test paper was attached to the solution film, and the pornography was observed after 1 minute. If the color of type A oil test paper is uniform and continuous and complete, it is high cleanliness, and vice versa, it is not qualified.