The aluminum foil bag turns yellow or black in color during use.cause:1. The temperature of the roller on the heat seal and the roller seal is too high during heat sealing;2, The machine speed is too slow, and the aluminum foil stays on the heating roller for too long;3, The temperature resistance of the pigment used in gold foil is too poor.Solution:1, Adjust the temperature of the heat sealing drum;2Appropriately increase the speed;3, It is recommended that aluminum foil manufacturers replace the pigments used in gold foil.