Bulk bags—also called FIBCs (flexible intermediate bulk containers), builders bags, or super sacks—are industrial containers used for storing and transporting bulk goods. They were designed to be a more cost-effective and environmentally efficient alternative to using multiple sacks. A single bulk bag can replace a pallet of sacks, reducing cost and material usage.
Bulk Bag Materials
Traditionally, bulk bags were made of PVC rubber, but modern-day FIBCs are fabricated from a woven polypropylene (PP) fabric, and hence they are sometimes referred to as PP bags. Polypropylene is resistant to mildew. It also has moderate resistance to heat, shrinkage, and stretching. Woven materials are stronger and more durable than nonwoven fabrics because the layers are woven over and under each other.
There is also a PVC variant, which is designed for expensive hygroscopic products that require protection from the harsh external environments. PVC bulk bags are manufactured from PVC-coated polyester fabric with welded seams, making them highly durable and completely watertight. Although they are more expensive than PP bags, the PVC version has a life expectancy of more than three years and can be repaired.
The strength, durability, and reliability of bulk bags make them an eco-friendly choice for carrying a broad range of materials, from sand and powder to pellets, aggregates, and plastic granules.
Reusing Bulk Bags
Super sacks are reusable if they have been treated correctly, but they must be multi-trip bulk bags with a 6:1 Safety Factor rating. Some companies provide FIBC cleaning services—covering collection, inspection, and cleaning—so that they may be returned for further reuse. Reuse of FIBCs encourages sustainability and a circular economy, as reusing refurbished bags reduces waste and dependency on raw materials.
Recycling Super Sacks
Bulk bags are recyclable. Most FIBCs are made from virgin PP, a common plastic that can be repurposed into other plastic products, such as battery cables, brooms, brushes, trays, bins, and auto parts.
The types of super sacks that are suitable for recycling include those used to store chemicals, fertilizers, grains, construction materials, pigments, and plastics. Bags for recycling are classified by different grades: Grade A (clean, bright white; colored stitching and handles allowed); Grade B (not as clean, predominantly white with minimal coloring); and Grade C (dirty or colored bags).
How FIBCs Are Recycled
As with other industrial plastics, the recycling process begins with proper collection. Recyclers require that the material be compacted into bales for easy collection and optimal market value. FIBCs are collected in large quantities, so recycling is usually feasible only for businesses with a sizeable output, or ones that can store the bags over time.
After collecting them, recyclers take the mill-sized bales to a reprocessing center, where they are sorted and cleaned. As they are commonly used to transport a variety of materials, including fertilizers and chemicals, bulk bags must be thoroughly decontaminated before being recycled. All zips and buttons are also removed.
Next, the bags are resized into small flakes, making them easier to handle for further processing. The plastic is fed through shredders and granulators with industrial blades that cut rotationally to chop it down.
After cutting, the plastic regrinds go through a separation process to differentiate contaminants from the plastic polymers. With today's advanced technology, machines can separate plastic by size, shape, color, melting point, and even the ability to absorb light.
The final phase is compounding, which involves putting the regrinds through an extruder, where they are melted down at 240 degrees Celsius into uniform beads, also referred to as pellets or granules. The mixture is strengthened through the addition of virgin polypropylene.
A variety of new products can be manufactured from the pellets as the bulk bag recycling process comes full circle. This loop can be repeated over and over, as polypropylene can be safely recycled many times. These bags present an eco-friendly option for many businesses that need to store and transport large quantities of goods.