How PP Woven Bags Are Made?

From rice and fertilizer to cement and construction materials, PP woven bags are everywhere. They protect food freshness, ensure safe storage of chemicals, and support building projects worldwide. But how are these durable bags actually made? Let’s take a closer look at the step-by-step production process.

Step 1: Main Materials Additives - Preparing PP/HDPE Granules with Stabilizers, Colorants Fillers

The main raw materials are PP/HDPE granules, mixed with stabilizers, lubricants, colorants, fillers, and UV agents. Both virgin and recycled materials can be used depending on the application.

New PP V.S. Recycled PP

Step 2: Drying & Mixing - Removing Moisture and Ensuring Homogeneous Blending

Raw materials are dried and mixed before extrusion to ensure stable processing and consistent quality.

Step 3: Tape Extrusion Winding - Turning Raw Material into Flat Tapes

Raw materials are melted, extruded, stretched, annealed, and wound into flat tapes.

• 3.1 High-speed extrusion lines are ideal for low recycled content and high output.
• 3.2 Low-speed (Energy-Efficient & Eco-Friendly) extrusion lines are suitable for 100% recycled materials or small-scale production.

Step 4: Circular Weaving - Turning Flat Tapes into PP Woven Fabric

Flat tapes are woven into durable fabric rolls using circular looms.

Options include:

• 4.1 Suspension-type circular loom (for high-quality flat tape)
• 4.2 Eco-friendly circular loom for recycled flat tape
• 4.3 Mesh bag circular loom for fruit and vegetable packaging
• 4.4 Large looms for jumbo bags or tarpaulins

Step 5: Printing & Laminating (Optional) - Enhancing Woven Fabric with Coating or BOPP Film

Three main options for woven fabric:

• 5.1 BOPP laminated fabric (pre-printed by rotogravure printing machine and laminated, no flexo printing needed)
• 5.2 Coated woven fabric (laminated, can be flexo printed)
• 5.3 Plain woven fabric (can be flexo printed or left unprinted)

Step 6: Cutting Sewing - Enhancing Woven Fabric with Coating or BOPP Film

Fabric rolls are cut and sewn into finished bags.

Machine options include:

• 6.1 Automatic woven bag cutting and sewing machine for standard PP bags
• 6.2 Cutting & sewing machine with liner inserting & hemming
• 6.3 Cutting & sewing machine with liner inserting & hot-melt tape sealing
• 6.4 Valve bag cutting & sewing machine
• 6.5 Cutting & sewing machine with perforation and handle punching for rice bags
• 6.6 Cutting & sewing machine with sheet-fed flexographic printing machine

Step 7: Bag Packing - Compressing and Bundling Bags for Easy Storage & Transport

Finished bags are compressed and bundled with hydraulic or pneumatic baling presses for easy storage and transport.

Step 8: Recycling - Reusing Edge Tapes and Defective Bags as Granules in Extrusion

Edge tapes, residual tapes, and defective bags are recycled into granules and reused in the extrusion line, promoting sustainability.

Conclusion

From raw materials to finished woven bags, the process is efficient, versatile, and sustainable. Qianfeng Machinery provides complete solutions for PP woven bag production.

Looking for a reliable partner for PP woven bag machinery? Contact Qianfeng today for a full catalog, pricing, or a customized solution.

Email: [email protected] / [email protected] 

WhatsApp: Camela+86-15868562229 / Leilei +8615868562226

Wenzhou Qianfeng Machinery Co., Ltd.