What is raw lacquer? What's the role?

Raw lacquer (natural lacquer), also known as "earth lacquer" or "national lacquer" or "lacquer", is a milky white colloidal liquid cut from knee wood. Once exposed to the air, it will turn brown, and after a few hours, the surface will dry and harden, forming patent leather. Raw lacquer has high economic value, good corrosion resistance, wear resistance, acid resistance, solvent resistance, heat resistance, water resistance and insulation, and is a high-quality polyester material for military industry, industrial equipment, agricultural machinery, infrastructure, handicrafts and civil furniture. It is also one of the important materials traditionally exported by China, which is famous for its quantity and quality.