Whiteboard paper is a kind of uniform fiber structure, with fillers and rubber components on the surface and a layer of paint on the surface. White cardboard is a kind of paper made by multi-roll calendering. The paper has high purity, uniform ink absorption and good folding resistance. Mainly used for commodity packaging boxes, commodity surface linings, picture wall charts, etc. Whiteboard paper has small elasticity and toughness, and it is not easy to break when folded. Mainly used for printing packaging boxes and commodity lining paper. In book binding, the spine for wireless binding and the middle diameter paper (spine) or cover of hardcover books. There are advanced and ordinary, single-sided and double-sided. According to the bottom classification, there are two kinds: gray and white.