... is no adhesive between lavers of the co-extruded poly film and each other,so there is no ... good function of each plastic resin,the co-extruded poly film make the bag have moisture-barrier,gas- ... and tear-resistant performances.The inner layer of the poly mailer bag is usually opaque,which ensures the ... of the packed goods.The outer layer of the poly mailer bag is clean creamy white,which is ...