Kraft paper making is a process of converting wood into wood pulp, the purpose is to remove the lignin from the cellulose in the wood fibers to make high quality paper. Kraft paper is widely used for packing paper, envelope, paper bag and so on.
The kraft paper making mainly divide into two steps: The Pulping Process and The Paper Making Process. In the pulping process, the raw material will be beating and pulping by drum pulper or D-type hydrapulper, then the pulp is conveyed by pulp pump into high density cleaner for removing heavy impurities, after that, the pulp will be coarse screening and fine screening by M.C. pressure screen, inflow pressure screen. After paper pulping process, the fine pulp will be conveyed into kraft paper machine for paper making, the pulp is formed wet sheet in wet end, and then go into the press section for removing water, after that the paper into the drying section for drying paper, then the finished paper is made.
The kraft paper pulp is stronger than other paper pulping processes, maintain high effective sulfur ratio or sulfidity for strengthen. In addition, the Kraft process is more efficient at removing the lignin and results in a stronger fiber.
