In the current screen printing of metal signs or non-metal material signs, there is a relatively large amount of ink used for printing. However, choosing the appropriate printing ink is not easy. The common printing inks used for sign and signboard screen printing include several types: 

Air-dried enamel printing ink: It is commonly made from alkyd resins and requires oxygen from the air to undergo a reaction for curing. The properties of alkyd enamel are determined by the type and quantity of the applied oil. The longer the drying time of the ink, the longer the drying time of the enamel. When the drying time is the required condition, the ink with a longer drying time generally has better surface durability characteristics. This type of ink is mostly used for outdoor metal material identification signs and plaques.