The production process of PP woven bags mainly includes the following key steps. The first step is filament drawing. Polypropylene granules are added to an extruder and heated at high temperature to melt and plasticize them. Then, they are extruded through a die into filaments, which are then cooled and stretched to improve their strength and toughness. These filaments are the basic material of the woven bag.
The second step is weaving. After filament drawing, the filaments are fed to a weaving machine for weaving. The weaving machine interweaves the filaments into a fabric using a specific weaving method. The weaving density and method affect the strength and durability of the woven bag. Common weaving methods include plain weave and bias weave, and different weaving methods are suitable for different application scenarios.
The third step is printing. According to the customer's needs, the woven fabric is printed. The printed content can be company logos, product information, instructions for use, etc. There are various printing methods, such as gravure printing and flexographic printing, each with different characteristics and applications.
The fourth step is cutting and sewing. After printing, the fabric is cut to the appropriate size and then sewn. The quality of the sewing directly affects the sealing and durability of the woven bag. Common sewing methods include flat stitching and overlock stitching; the appropriate sewing method should be selected based on the intended use.