A long time ago, "kraft paper" was really made of calf skin. Of course, this kind of "kraft paper" is now only used when making drum skins; and the kraft paper you use for wrapping books is made by chemical methods from the wood fibers of coniferous trees after people have learned the technology of papermaking. Pulp, then put it into a beater for beating, then add sizing material, dyes, etc., and finally copy it into paper in a paper machine. Because the color of this kind of paper is yellow-brown, the paper is tough and looks like cowhide, so people call it kraft paper.
In fact, the manufacturing methods of kraft paper and ordinary paper are not much different. Why is kraft paper stronger than ordinary paper? This is mainly because the wood fibers used in making kraft paper are relatively long, and when cooking wood, they are treated with caustic soda and alkali sulfide chemicals, so that their chemical effects are relatively mild, and the original strength of wood fibers is damaged. It is relatively small, so the paper made of this kind of pulp has tightly interdependent fibers, so kraft paper is very strong.
Kraft paper is named for its toughness and firmness like cowhide, and it has good strength and burst resistance. Kraft paper is divided into single-sided, double-sided and striped kraft paper, which is often used to make envelopes, document bags, etc. In the packaging industry, the cost of making paper bags with kraft paper is lower than that of coated paper, and the paper bags are durable and have better stiffness. The background color and texture of kraft paper can also achieve special visual effects when packaging certain products. In addition, kraft paper is also commonly used to laminate corrugated board.
