9408 can be used in water-based substrate wetting and solvent-based substrate wetting. It has excellent spreading properties, good recoating and flowability promotion, and can greatly improve adhesion. It can help paint or ink to wet the surface of various substrates, even can wet substrates with very low surface energy, so, the surface defects such as shrinkage holes or edge shrinkage can be prevented, and the flow, leveling and adhesion of the paint film are improved. It is effective even the addition amount is extremely low. When this product is mixed with the system solution in a certain proportion, it can reduce the contact angle between water and the substrate, thus increase the coverage of the coating system and improve the wetting effect of the substrate.