Disclosed is a sealed bag and a processing method thereof, the method including presetting a folding baseline on a base paper piece, and performing a first plastic sealing on a gap between an overlapping area of the second folding portion and the first folding portion so as to form a paper roll; supporting the paper roll so as to perform side pressing on the paper roll so that the paper roll is embedded to form a first closing and a third folding line, wherein the area between the first folding line and the first side pressing line serves as a bottom surface of the first closing, and the area between the first side pressing line and the third folding line serves as a top surface of the first closing; plastically sealing the bottom opening of the fully pressed paper roll to form a finished sealed bag.

A method of producing flexible polypropylene fabric bags with heat fused seams comprising providing fabric pieces, wherein each fabric piece has a coated side and an uncoated side; positioning fabric pieces so that a coated side of one fabric piece faces a coated side of another fabric piece; selecting an area of fabric to be joined for forming a seam or joint; applying heat to the area to be joined that is less than the melting point of the fabrics, for forming one or more seams or joints and wherein the heat fused seams or joints of a resulting polypropylene bag retains at least 85% of the fabric strength without using sewing machines.