来源：http://jnggsdz.com 发布时间：2020-11-03 14:55:37
Before the aluminum coil is rolled, some pretreatment sections are needed to ensure the surface of aluminum coil is clean. In order to avoid the existence of residual grease and smooth agent on the surface of the coating and application. Therefore, the aluminum coil should be pretreated in the following aspects before forming.
First of all, may as well use hot water to wash the aluminum roll. Hot water scrubbing is mainly to clean the residual degreaser on the surface of the substrate to ensure that these residues can be dissolved, so as to prevent the secondary pollution of these degreasers on the substrate. The application methods are mostly immersion and spray brushing. The hardness of the water used should not be very high, otherwise, minerals in the water will form mineral spots on the surface of the substrate.
Secondly, due to the fast linear speed of precoating line, the degreasing agent usually has a high concentration. The typical degreasing agent contains sodium hydroxide (NaOH), sodium carbonate (Na2CO3), sodium silicate (Na2SiO3), phosphate and other components. The hot alkali degreasing process is usually divided into two steps to ensure that the surface of aluminum coil substrate is washed clean, and spray brushing is often used.
Thirdly, it is passivated. Passivation is to form conversion film on the surface of substrate by pressure spray, dip coating or roller coating. Usually using the way of pressurized spray, the sludge produced in the process of passivation liquid often congests the spray hole, thus affecting the efficiency of spray. Although the dip coating method can deal with this problem, the amount of passivation solution is large. Both of the above two methods require water to clean the excess passivation liquid in the essential operation, which will lead to the recovery and purification of wastewater. Roller coating is a good passivation construction method, with the advantages of average coating, economic applicability and no need of washing. Chromate / oxide type treatment agent is usually used for aluminum plate, which contains chromate, chromic acid, phosphoric acid and promoters fluoride and molybdate. Phosphoric acid must be added to this kind of treatment agent, otherwise it can not be used to treat aluminum plate for food and beverage.
From all the market conditions, people's demand for high-end products is still increasing. We are quite resistant to fake and inferior products. Aluminum coil will also become a part of the products we need, which makes our products more beautiful and more advanced. Aluminum coil has been used in electronics, packaging, construction, machinery and other aspects. In the future development, aluminum coil can still occupy a part of the market, and the number of aluminum coil manufacturers will gradually increase. The competition of products will come down to the competition of skills and brands.