When the hydrophilic aluminum foil is used as a heat exchanger, there are high requirements for the coating properties such as adhesion, corrosion resistance and hydrophilicity. In order to ensure the coating performance of the hydrophilic aluminum foil, the pre-treatment before coating is especially important.
The currently used degreasing agent is an alkaline solution containing Na+, and the suitable working temperature is 20-40 °C. When the degreasing temperature is too low, the activity of the degreasing agent is low, and the reaction with the oil on the surface of the aluminum foil is slow, which affects the cleaning effect of the aluminum foil surface.
When the temperature of the degreasing liquid is higher than 40 °C, the activity of the degreasing agent is higher, and it can react violently with the oil on the surface of the aluminum foil, and the cleaning effect is better.
However, if the concentration of the degreasing solution is too high or the degreasing time is too long, it will cause corrosion spots on the surface of the aluminum foil, which will affect the coating production.
In order to prevent the residual alkaline degreasing solution from affecting the surface of the aluminum foil, the aluminum foil needs to be cleaned twice. Because the activity of the degreasing liquid is stronger when the temperature is above 40 °C, in order to effectively clean the degreasing liquid on the surface of the aluminum foil and the oily mixture after the reaction, the temperature of the hot water cleaning tank is controlled at 40-60 °C.
At the same time, after the hot water rinsing tank, it will be washed by the normal temperature water to ensure that the degreasing liquid on the surface of the aluminum foil and the reaction mixture between the degreasing liquid and the oil stain are thoroughly cleaned.
After the cleaning and pretreatment of the aluminum foil, it must be dried before coating production to ensure that the surface of the aluminum foil is clean and dry during the coating production, so as to prevent the color difference and missing coating defects caused by the wet surface of the aluminum foil during the coating production, which will affect the coating quality.
The temperature of the drying furnace gas is controlled at 300~400 ℃ to ensure that the surface of the aluminum foil is dry and will not be deformed or wrinkled due to excessive temperature, so as to ensure the quality of coating production.
Through pretreatment, the the adhesion of its coating film is strong, the corrosion resistance is good, and the continuous hydrophilicity is good, which can meet the production needs of different customers for hydrophilic aluminum foil.
As an air conditioner aluminum foil manufacturer, Haomei Aluminum can supply plain aluminum foil and different types of hydraulic aluminum foils like gold or blue hydrophilic aluminium foil. Welcome to leave message below to inquire what you need.
In order to maintain the temperature and concentration of each cleaning tank, squeeze rollers are installed at the outlets of the degreasing liquid cleaning tank, hot water cleaning tank and normal temperature water cleaning tank.