The construction process of gold paint metal packaging coatings directly affects the final coating effect and product quality. From the preparation before construction to the specific operation steps, each link needs to be carefully controlled to avoid various coating defects and ensure that the easy-open lid is both beautiful and has good protective performance.
Cleaning and pretreatment before construction are basic and key steps. If there are impurities such as oil, dust, oxide film, etc. on the metal surface of the easy-open lid, it will seriously affect the adhesion of the gold paint. Therefore, it is necessary to use a suitable detergent to thoroughly clean the metal surface to remove these impurities. After cleaning, it is also necessary to perform surface roughening treatment to form a tiny concave and convex structure on the metal surface to increase the contact area between the metal packaging coatings and the metal and enhance the adhesion. If the pretreatment is not sufficient, the gold paint may peel and fall off after drying, which will not only affect the appearance, but also reduce the protective ability of the metal.
The control of the construction environment has a significant impact on the effect of gold paint coating. The temperature and humidity of the environment need to be kept in an appropriate range. When the temperature is too low, the viscosity of the gold paint will increase and the fluidity will deteriorate, making it difficult to cover evenly when brushing or spraying, and it is easy to have defects such as flow marks and brush marks; when the temperature is too high, the solvent evaporates too quickly, and the gold paint may dry before it is fully leveled, resulting in an uneven surface and even pinholes. In terms of humidity, excessive humidity will cause the gold paint to absorb too much moisture during the drying process, causing the coating to turn white and the glossiness to decrease. In severe cases, it may also cause the coating to mold. Therefore, an environment with suitable temperature and humidity should be selected during construction. If necessary, the environmental conditions can be adjusted by air conditioners, dehumidifiers and other equipment.
The mixing process of metal packaging coatings should not be ignored. Before use, gold paint usually needs to be diluted or mixed with other additives according to construction requirements. The selection and dosage of diluents are crucial. If the diluent does not match the gold paint, it may cause adverse reactions in the components of metal packaging coatings, affecting the drying speed and coating performance; if the amount of diluent is improper, the metal packaging coatings will be too thick and difficult to apply, and too thin will make the coating thinner, reducing the protective effect and decorativeness. In addition, the mixing process must be ensured to be uniform. If the mixing is not sufficient, the pigments, resins and other components in the gold paint will be unevenly distributed, and the color and performance of the dried coating will also be different, resulting in color difference or poor performance of the local coating.
The selection and use of construction tools are also critical. Different construction methods, such as spraying, brushing, and roller coating, have different requirements for tools, and each has its own advantages and disadvantages. Spraying can obtain a uniform and smooth coating, but it has high requirements for equipment and operating technology. If the pressure, distance, and angle of the spray gun are not properly controlled, it is easy to have problems such as poor atomization and sagging; brushing and roller coating are relatively simple, but if the quality of the brush or roller is not good, or the force is uneven and the speed is inconsistent during operation, it will leave obvious brush marks and roller marks, affecting the beauty of the coating. Therefore, it is necessary to select appropriate tools according to actual needs and construction conditions, and master the correct use methods to ensure that the coating is uniform and smooth.
The operating specifications during the construction process are the key to avoiding coating defects. Whether it is spraying or brushing, a certain order and method must be followed. When spraying, the spray gun should be kept moving at a constant speed, and the thickness and overlapping area of the spraying should be controlled to avoid local over-thickness or over-thinness; when brushing, it should be done in one direction, and the number of back and forth brushing should be minimized to prevent bubbles and brush marks. The drying time of each layer of coating must also be strictly controlled. If the next layer is applied before it is completely dried, the bonding between the coatings will not be strong, and stratification and peeling will easily occur. At the same time, during the construction process, external impurities such as dust and fibers should be prevented from falling into the wet film, otherwise particles will form on the surface of the coating, affecting the appearance quality.
There are also many influencing factors in the drying process of the coating. Drying methods generally include natural drying and forced drying. Natural drying should ensure that the environment is well ventilated to avoid the coating surface from drying slowly due to poor air circulation, and even produce odors; when forced drying, the temperature and time should be controlled. Excessive temperature may cause the coating surface to dry quickly to form a hard shell, while the internal drying is insufficient, resulting in cracking, bubbling and other problems; if the time is insufficient, the coating cannot achieve the expected hardness and performance. In addition, during the drying process, the coating should be prevented from being hit or rubbed by external forces to avoid damaging the coating surface.
The construction of gold paint metal packaging coatings requires strict control in cleaning pretreatment, environmental control, metal packaging coatings preparation, tool use, operation specifications and drying. Only by paying full attention to these matters and strictly following the construction requirements and standards can we effectively avoid coating defects and make the easy-open lid present an ideal golden appearance and good protective performance to meet the use requirements of metal packaging.
