FIBC Bags with Sift Resistant Seams

FIBC bags are a flexible packaging option. you can store or transport dry Flow-able material/product in these bulk packaging FIBC bags.

FIBCs are made with woven polypropylene which are constructed by weaving strands of polypropylene together. This weave is what puts the flexible in FIBC. Because of this weaved construction, fine materials may seep through the weave or the stitch lines causing a loss of product and creating quite a mess wherever the bag is.

No bag is 100% sift-proof, but there are a few different ways to prevent very fine products from seeping out of FIBC bags. 

During the manufacturing process, sewing machine needles make small holes in the fabric of the bag. These can cause a leak if the bag is filled with fine products/materials.If you have product/material seeping through your bag, you have two options. 

     

One option is using a coated FIBC bag 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.

The second option that you have is using FIBC bags with sift-proof/sift resistant seams. Inserting a sift-proof/sift-resistant seam into the bag involves using a felt or Soft type yarn in the sewing process. The sewing operator feeds the sift cord along the seam of the bag when sewing, filling the areas near the needle hole in the seam. At times, felt is used as the sift resistant material and is sewn either along the threaded seam or in between the fabric panels.

The Strongest sift-proof/sift-resistant seam design available involves one strip of felt between the polypropylene seam with filler cord on the top and bottom of the seam. In most cases, coated bags are the most cost-effective option and work for most products.for most granular and some powder materials, coated bags are a great option. If your product/material still seeps through a coated bag, a sift-proof/sift-resistant bag is probably best for you. These bags are perfect for hauling products/materials that are very fine powders such as milk powders, iron powders and resins.