Aluminum foil surface quality is the most important […]
Aluminum foil surface quality is the most important factor affecting the peel strength, the main surface quality problems are oil spots, corrosion, peroxide and so on.
1 oil spots
Oil spots are the most common quality problems on the surface of aluminum foil. The main reason is that the oil in the rolling oil is mixed with the oil or the oil of the rolling oil. In addition, the angle of the tuyere at the exit of the mill is not correct, the wind pressure is too small, The oil on the net. The solution is: ① to prevent the oil mixed with rolling oil; ② control of the rolling oil kinematic viscosity, not more than 2.34 × 10-6m2 / s; ③ cold weather heating should be rolling; ④ control the addition of additives The amount of 5% -7%; ⑤ at the exit of the mill to increase the upper and lower two rows of tuyere, the upper row of two tuyere, the lower row of four vents, blowing from the middle to both sides; ⑥ in the last rolling pass Off the aluminum foil surface of the oil; ⑦ aluminum foil annealing, stay at 200 ℃ for some time, so that the rolling oil fully volatile.
Many people to aluminum foil corrosion and oxidation of confused, in fact, the two are completely different, corrosion is the loss of aluminum atoms to form white powder, the product has no protective effect on the matrix; oxidation is the oxidation of aluminum atoms and oxidation of oxides, the product of aluminum matrix Have a protective effect. Aluminum in the nature itself will form a layer of about 1 / 500μm oxide film, from the role of self-protection. Aluminum foil is corroded after the formation of white ash will seriously reduce the peel strength of plastic film. Aluminum foil is corroded by water or lye. Aluminum foil in the transport process by rain water is a common cause of corrosion. The other is overlooked by the fog caused. Aluminum foil in the high temperature of the long-distance transport at night, the aluminum coil side of the cooling soon, the other side in the high temperature, cooling fog condensation in the above and into the aluminum coil, transported to the customer's warehouse, Sad and the side of the low-temperature heating, resulting in corrosion of aluminum coil. The solution is: ① aluminum volumes tightly packed, prevent rain; ② not packaging and transport high temperature state of the aluminum coil.
Aluminum surface of the natural formation of a layer of oxide film has a protective effect, but if the high temperature in the case of strong wind cooling, is bound to cause peroxidation, surface discoloration such as rainbow. Peroxidation of aluminum foil also reduces the peel strength of the plastic foil. Prevention method is aluminum foil annealing can not be used after the strong wind blowing cold, let it slowly cooling.