What is Coated and Uncoated FIBC Bags
About “Uncoated” FIBC Bags
FIBC bags are typically constructed by weaving together strands of polypropylene. Because of the weaved construction, materials that are very fine may seep through the weave or sew lines. Examples of these products is fine powders or sands.
If you’re packing a powder in an uncoated bag and you hit the side of a full bag, you might see a cloud of product leave the bag. For some applications, this is perfectly fine. For others, it’s not. The weave of an uncoated bag also allows air and moisture to more easily pass through the polyethylene to the product you’re packing.
Uses of Uncoated FIBCs
- For storing and transporting granular and is the size of grains of rice or larger such as beans, grain, popcorn, and seed.
- Transporting products and goods that need to breathe.
- For storing and transporting food grade and non-food grade products.
A “coated” bag is constructed similarly to an uncoated bag; however, before the bag is sewn together, an additional polypropylene film is added to the bag’s fabric sealing the small gaps in the poly weaves. This film can be added to the inside or outside of the bag.
Inside the bag is the most common because it can keep products like powders from getting stuck in the weave when discharged. The coating can be difficult to detect if you’re not very familiar with FIBC. The easiest way to tell if a fabric is coated is to press the weave together to see if it spreads apart. Make sure to test both the outside and inside of the bag. If the weave does not spread apart, there’s a good chance the bag is coated.
Advantages of Coated Bag
The benefits of a coated bag are the additional protection it provides the materials being stored and transported. FIBCs can be found in warehouses, construction sites, and manufacturing facilities. These are environments where outside contaminants like dust, moisture, and dirt can be a factor. The coating on a bag can provide a moisture barrier and an added layer of protection. If you are packing a powder and you hit the side of the bag when it’s full, you will not likely see a cloud of product exit the bag like an uncoated bag. Coated bags are very useful when packing small granular or powdered product.
- When you’re transporting dry flowable products in powder, granule or flake form such as cement, detergents, flour, salt, fine minerals such as carbon black, sand and sugar that need moisture protection.
- When a barrier from water/moisture is needed.
- Poly liner may be used along with a coated bag to add an extra layer of protection.