The double-zero aluminum foil tackiness phenomenon includes two layers of meaning: the mechanical properties of the aluminum foil are not suitable for use and the degreasing effect of the aluminum foil surface is poor, which causes the aluminum foil to be peeled off during use. By improving the finished annealing process and controlling the rolling oil volume and its physical and chemical properties in the rolling process, the parameters of the tension of the slitting and slitting are adjusted to eliminate the stickiness defect of the aluminum foil. Aluminum foil is soft and hard according to the production state. Most of the double-zero foil is used after softening annealing. The softening annealing is not only to control the mechanical properties of the aluminum foil, but also to eliminate the residual oil on the surface of the aluminum foil, to obtain a smooth and bright surface, and to Free to expand. Aluminum foil for different purposes, the required degree of degreasing is different, such as aluminum foil for composite use and aluminum foil for capacitors. However, in recent years, users have become more and more demanding on the quality of double zero foil. Aluminum foil sticking becomes one of the main defects. The soft state double-zero foil sticking phenomenon is mainly manifested as: the double-zero foil feel is “soft”, and it is not easy to maintain a flat plate shape during the user's use; double zero foil roll layer and layer Inter-adhesion, severe formation of "knot", in the process of unwinding, the peeling is difficult, resulting in aluminum foil can not be used normally. Seriously affected the production and sales of aluminum foil.
Solution to the problem of tackiness of double zero aluminum foil:
1. Improvement of annealing process
(1) Principle of double zero foil finished annealing system Generally, the purpose of double zero foil annealing is to obtain certain plasticity; the second is to obtain the surface quality of bright, clean and no residue. In the past, the main considerations for the development of double zero foil finished annealing process were the recrystallization temperature of pure aluminum foil and the distillation range of rolling oil. Since the recrystallization temperature of the pure aluminum foil is about 240 to 260 ° C, the distillation range of the aluminum foil rolling oil is generally about 200 to 260 ° C. In the past annealing process, the annealing temperature is generally 300 to 400 ° C, and the annealing period is 10 to 40 h. This kind of annealing system, due to high temperature, oil burning, oil film carbon chain decomposition and oxidation, causing aluminum foil pollution, resulting in yellow brown oil spots.
(2) Insufficient annealing process of double zero foil finished products In recent years, the so-called low temperature long-time annealing process has been gradually adopted. The annealing temperature is not lower than 280 ° C, and the annealing time can reach 150 h, but the effect after double zero foil annealing is not ideal. Is the annealing temperature of the double zero foil higher than the recrystallization temperature of the pure aluminum foil? If the annealing is performed below the recrystallization temperature, can the user's use requirements be met? What is the effect of degreasing at low temperatures? How to master the annealing temperature and time can ensure that the surface quality of mechanical properties meets the requirements, which is a question that must be answered through experiments.
(3) Basis for the development of the new annealing process The main parameter of the annealing process is the annealing time, which depends mainly on the amount of furnace, the width of the foil roll and the winding diameter. The amount of furnace is large, the larger the coil diameter, the wider the foil, the longer the annealing time. Under the premise of degreasing effect, the annealing temperature should be as low as possible, regardless of whether the aluminum foil is fully recrystallized. Meeting the user's requirements is the basis for developing a new annealing.
(4) Application effect of new annealing process Annealing test of aluminum foil in circulating air furnace. Taking into account the elimination of the edge of the aluminum foil roll, slow heating, slow cooling, using a stepped heating system. The annealing time was tested according to the aluminum foil winding diameter and the width of the aluminum foil. The mechanical properties of the aluminum foil, the adhesion of the aluminum foil and the degreasing performance of the aluminum foil were investigated according to different annealing temperatures. Annealing test combined with industrial production, using 10t box type circulating air furnace, heating power is 360kW, the maximum heating temperature is 535 °C. The alloy state of the test aluminum foil is 1235-O, the thickness is 0.006-0.007 mm, the winding diameter is 300-500 mm, and the widths are 350, 460, 520, 787, 920, 1024, 1216 mm, respectively. According to the specification of the test aluminum foil annealing time (heating + Insulation + cooling) is 30 ~ 150h, annealing temperature is 180 ~ 300 ° C. The test methods for the mechanical properties, adhesion and degreasing of aluminum foil are respectively carried out in Appendix C to Appendix E of GB3198-1996. The tensile test equipment is ZLD-10 electronic tensile testing machine. The test results are shown in Table 1. According to the test data, after analysis and research, it is determined that the annealing temperature of industrial production is below 250 °C, which can eliminate the sticky defect of aluminum foil. Table 1 Aluminum foil annealing test results Comparison annealing temperature / °C σb / MPa δ /% Degreasing open-loop characteristics 280 ~ 250 41 ~ 69 0.5 ~ 1.0 A-level easy adhesion 240 73 ~ 89 0.5 ~ 1.0 A grade L ≤ 200mm 230 76 ~ 91 0.5～1.0 A grade L≤200mm 220 87～98 1.0 B grade.