Kraft paper (Kraftpaper) is the strongest paper. Today, it is mainly made of wood fiber through chemical methods. The wood pulp content in kraft paper is almost 100%. Kraft paper is paper or cardboard (cardboard) made from chemical pulp produced in the kraft paper process. Kraft paper process or sulfate pulping process is a process used to produce pulp. In a large pressure vessel called a digester, sodium hydroxide and sodium sulfide are used to separate lignin from the wood chips to obtain cellulose, the main ingredient. (Wikipedia, the free encyclopedia)