耐指纹镀锌板的耐指纹处理的原理
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由于家用电器的蓬勃发展，镀锌板的表面处理方法多种多样，对性能的要求也各不相同，其中使用最多的是抗指纹处理。
1） 防指纹处理功能
抗指纹处理是在镀锌板表面涂覆一层非常薄且透明的有机树脂膜，可防止操作人员的指纹在镀锌板生产加工过程中粘附在产品上，影响产品外观。同时，还可以提高产品的耐腐蚀性，改善成型加工过程中的润滑性，并作为后续涂层的粘合剂底层。
2） 抗指纹涂料
抗指纹处理涂层最好在钝化后进行，以便与钝化膜一起工作，使产品不仅具有良好的外观，而且具有良好的耐腐蚀性。
可作为抗指纹涂料的水溶性树脂有很多种，如丙烯酸树脂、聚氨酯树脂等。丙烯酸树脂具有颜色浅、透明度高、耐热性、耐腐蚀性、柔韧性和加工性好等特点。同时，它对镀锌板有很强的附着力。广泛应用于抗指纹涂料中。聚氨酯树脂具有很强的耐腐蚀性，应用广泛。
3） 抗指纹成膜工艺
采用滚涂法在镀锌板表面涂覆抗指纹涂层。涂层中的有机树脂以微粒形式悬浮在水相中。干燥时，水逐渐蒸发，体积减小。这些分散的聚合物颗粒逐渐相互接近。颗粒之间的毛细压力迫使颗粒紧密挤压。随着水的蒸发，压力继续增加并使颗粒变形，最后，颗粒相互融合形成连续的有机膜。因此，耐指纹处理后的干燥温度和时间非常重要，否则会导致涂层固化不良，并导致钢卷内各层镀锌板之间相互粘合。一般情况下，膜厚为1μM，干燥时，板温约为110℃，然后冷却至室温进行卷取。
4） 抗指纹膜的组成
抗指纹膜分为反应层、浓缩层和润滑层，分别赋予抗指纹膜耐腐蚀、润滑、抗指纹、附着力等性能。
钝化液涂在镀锌板表面并干燥后，成膜过程分为四个阶段：
第一阶段：湿膜涂布：有效成分均匀分散在水介质中；
第二阶段：湿膜中未结合水的挥发；
第三阶段：树脂乳胶粒子表面分散剂的分离→ 粒子间的融合
第四阶段：理想成膜状态，结合水/分散剂完全分离，粒子完全交联和完全融合。
Due to the blooming of household electrical appliances, there are a wide variety of surface treatment methods used by galvanized sheet, and the requirements for performance are also different, among which the most used is fingerprint resistant treatment.
1) Anti fingerprint processing function
Fingerprint resistant treatment is to coat a very thin and transparent organic resin film on the surface of galvanized sheet, which can prevent the fingerprint of operators from adhering to the product and
affecting the appearance of the product during the production and processing of galvanized sheet. At the same time, it can also improve the corrosion resistance of products, improve the lubricity during forming and processing, and serve as the adhesive
bottom layer for subsequent coating.
2) Fingerprint resistant coating
The fingerprint resistant treatment coating is preferably carried out after passivation, so as to work together with the passivation film to make the product not only have
good appearance, but also have good corrosion resistance.
There are many kinds of water-soluble resins that can be used as fingerprint resistant coatings, such as acrylic resin, polyurethane resin, etc. Acrylic resin has light color, high transparency,
good heat resistance, corrosion resistance, flexibility and processability. At the same time, it has strong adhesion to galvanized sheet. It is widely used in fingerprint resistant coating. Polyurethane resin has strong corrosion resistance and is widely
used.
3) Fingerprint resistant film forming process
Fingerprint resistant coatings are applied to the surface of galvanized sheet by roll coating method. The organic resin in the coating is suspended in the aqueous phase as tiny particles.
When drying, the water gradually evaporates and the volume decreases. These dispersed polymer particles gradually approach each other. The capillary pressure between the particles forces the particles to squeeze tightly. With the evaporation of water,
the pressure continues to increase and deform the particles, Finally, the particles fuse with each other to form a continuous organic film. Therefore, the drying temperature and time after fingerprint resistance treatment are very important, otherwise
it will cause poor curing of the coating film and mutual bonding between various layers of galvanized sheets inside the steel coil. Generally, the film thickness is 1 μ M. when drying, the plate temperature is about 110 ℃, and then it is cooled to room
temperature for coiling.
4) Composition of fingerprint resistant film
The fingerprint resistant film is divided into reaction layer, concentration layer and lubrication layer, which give the fingerprint resistant film corrosion resistance,
lubrication, fingerprint resistance, adhesion and other properties respectively.
After the passivation solution is coated on the surface of galvanized sheet and dried, the film-forming process is divided into four stages:
Stage I: wet film
coating: the effective components are evenly dispersed in the aqueous medium;
Stage II: volatilization of unbound water in wet film;
Stage III: separation of surface dispersant of resin latex particles → fusion between particles
Stage
IV: ideal film-forming state, complete separation of bound water / dispersant, full cross-linking and complete fusion of particles.
