The outer layer is made of refined white or yellow kraft paper, and the inner layer is PP plastic woven cloth. The PP plastic particles are melted under high temperature and high pressure, and the kraft paper and PP plastic woven cloth are laminated together. The outermost layer is covered with a layer of BOPP film, which is not only moisture-proof, but also has an attractive appearance and is resistant to stains. PE plastic inner film bags can be added for even better moisture-proofing.