Also known as corrugated board. It is made of at least one layer of corrugated paper and one layer of cardboard (also called cardboard), which has good elasticity and ductility. It is mainly used to make packaging materials for fragile goods such as cartons and carton sandwiches. This paper is mainly made of indigenous straw pulp and waste paper, which is similar to yellow paperboard, and then rolled into corrugated shape through mechanical processing, and then bonded to box paper with sodium silicate and other adhesives on its surface.