How much do you know about ordinary woven bags and their processing technology?

Ordinary woven bags are made of polypropylene (PP) as the main raw material through extrusion, wire drawing, weaving, weaving and bag making. PP is a semi transparent and semi crystalline thermoplastic, which has the characteristics of high strength, good insulation, low water absorption, high thermoforming temperature, low density and high crystallinity. It is the main raw material for making woven bags. Modified fillers usually include glass fiber, mineral filler, thermoplastic rubber, etc.

Woven bags are widely used. At present, woven bags are mainly used for agricultural product packaging, cement bag packaging, food packaging, geotechnical engineering, tourism transportation, flood fighting materials, etc.

Woven bags mainly include woven bags (non laminating woven bags), composite woven bags and various woven fabrics.

The production process of woven bag is: woven cloth becomes woven bag through printing, cutting and sewing. Depending on the equipment used, it can be cut before printing, or printed before cutting. Automatic cutting and sewing can continuously complete printing, cutting, sewing and other processes. It can also be made into valve pockets, bottom bags, etc. for plain woven fabrics, it can be made into bags after middle seam bonding.

The production process of composite woven bag is to compound or coat the woven cloth, coating material and paper or film. The obtained cylinder cloth or sheet cloth can be cut, printed, stitched and made into an ordinary seam bottom bag, or perforated, folded, cut, printed and stitched into a cement bag. The obtained sheet cloth can be bonded, printed, cut and pasted into a paste bottom bag. It can also be welded, rolled and made into tarpaulin and geotextile.

Plain woven fabrics can be coated or uncoated to produce tarpaulins, geotextiles, etc. cylindrical fabrics can also be coated or uncoated to produce tarpaulins or geotextiles, etc.

The technical indexes of flat wire production process are mainly divided into four categories:

1、 Physicochemical modification index. It mainly includes blending modification, mixing ratio, addition ratio of functional additives and mixing ratio of waste recycled materials;

2、 Physical and rheological indexes. It mainly includes draft ratio, expansion ratio, draft ratio and retraction ratio;

3、 Mechanical performance index. It mainly includes breaking force, relative breaking force, elongation at break, linear speed and linear density deviation;

4、 Tolerance dimension index. There are mainly flat wire thickness, flat wire width, etc

Lining bag process, polyethylene material is heated by extruder, melted, plasticized and extruded stably; Extruded into cylindrical film through die; Blow with compressed air to form tube bubbles; It is cooled and shaped by the cooling air ring and pulled into the herringbone splint for folding; To the winding roll through the traction roll and drive roll; Carry out cutting and heat sealing processes, complete the production of lining bags and bagging.

The production of pure polypropylene for flat filament can not meet the requirements, and a certain proportion of high-pressure polyethylene, calcium carbonate and color masterbatch must be added. Adding a small amount of high-pressure polyethylene can reduce the viscosity and melting speed of the material flow in the extrusion process, increase the fluidity, improve the toughness and flexibility of flat wire and woven bag, maintain a certain elongation at break, and improve the low-temperature impact of polypropylene.

The addition of grafted polypropylene can reduce the processing temperature and pressure. Improving the flow and adhesion of materials can improve the tensile strength. The addition of calcium carbonate can change the defects of transparency and opacity, reduce the harmful static electricity caused by friction in the process of stretching and weaving, increase the ink adhesion of printed trademark patterns, reduce the natural shrinkage of finished products during storage and reduce the cost.

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