The production of the polypropylene woven bags sacks involves vast complex technological procedures which requires sufficient infrastructure. In order to roll out strong and durable bags the production methods are designed in step by step way to ensure quality products. The main process is bifurcated into 4 major sub-groups which includes granulation of polypropylene, flat wire drawing, circular weaving and post processing of the fabrics. Plastic Granulation Powder of the polypropylene materials along with calcium carbonate and other additives are mixed in appropriate proportions which are then poured into the hopper. These materials are subjected to be poured into the barrels through a feeding port. The process of melting and plasticizing ensures the formation of strips which are further extruded and later cooled down by water tanks. These strips are then granulated and are screened before transporting them for the boiling drying treatment. The materials are piled up in the material pool where a feeder is there to suck these into the storage tank. This entire process is summed up by quantitative packaging after each of the particles undergoes an inspection. Polypropylene drawing process To serve the purpose of shearing the materials are heated inside the extruder at around 190-250 ℃. After shearing and shaping under constant pressure the films of the plastic are cooled in water and are cut down by the blades into embryo wires from which flat filaments are formed in the oven. Circular weaving The warp frame contains a porcelain hole, the thread pressing rod which is the first long vertical plate followed by the diameter feeding guide rod, the wire guiding rod, the second vertical plate, magnetic hole, the brown wire, tension rod, steel buckle, the warp fixing ring and the cloth base. From each of the bundles of spindles the yarn is drawn out. After loading the yarn into the shed the shuttle is being pushed by a shuttle pushing device which makes the shuttle move in a cyclic way. A traction equipment is situated at the top of the loom which pulls the fabric in the upward direction. The winding diameter of the yarn is made about 0.8mm after which the next process initializes. Post Processing The post processing procedures of the weaved fabrics are generally same in broader aspects. However, there are certain differences in each methodology which differentiates the process of post processing from each other. For example, the production process of coated polypropylene bags are different from that of uncoated PP woven bags. The single layered PP woven fabrics are also used as geotextile, mattress covers, tarpaulins etc.
