Specialty Bulk Bags: FIBC Big Bags with Sift Resistant Seams

Specialty Bulk Bags: FIBC Big Bags with Sift Resistant Seams

Bulk bags are an extremely versatile bulk packaging option. If the material/product is dry and flowable, you can store or transport in these amazing bulk packaging bags.

All FIBCs are made with woven polypropylene which are constructed by weaving strands of polypropylene together. This weave is what puts the flexible in “Flexible Intermediate Bulk Container” (FIBC). Because of this weaved construction, very fine materials/products may seep through the weave or the sew 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 bulk bags. Let's determine and explore these different methods of preventing very fine products from sifting through FIBC’s.

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My product is seeping/sifting through my bulk bag. What are my options?

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 very fine products/materials.

If you have product/material seeping through your bag, you have two options. One options is using a coated bulk bag. It’s the most common and prevents most products/materials from sifting through the bag. For more information on coated bags, see our blog post “How to Choose Between Coated and Uncoated Bulk Bags for Your Application” by clicking here

The second option that you have is using bulk bags with sift-proof/sift resistant seams. Inserting a sift-proof/sift-resistant seam into the bag involves using a felt or spongy 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 most robust 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.


FIBC Big Bags with Sift-Proof/Sift-Resistant Seams Use

As stated above, for most granular and some powder materials/products, 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/or resins.

For more information on sift-proof/sift resistant bags, contact our team of experts by scheduling some time to speak with us or by giving us a call.


Thanks for reading! 

product weight + calc.pngThanks for reading this post! We hope this helps you determine if a sift-resistant seam is right for your application.

Safety and reliability are our top priorities. Each bag that we sell has a safe working load (SWL). To make sure the product you’re packing will not exceed the SWL of the bag you’re interested in, you’ll need to know the bulk density of the product you’re packing as well as the cubic foot capacity of the bag.

Click the button below to download our Product Weight Guide and FIBC Volume Calculator to help you determine how much weight a specific bag will hold.


June 19, 2017

Categories: Bulk Bag Construction

About the Author: Jenny Rosa

Jenny Rosa is an Account Manager for the industrial bag division of Rapid Packaging and National Bulk Bag. She received her Associates Degree from St. Cloud State University and was previously a researcher at JNR Adjustment.

Jenny's background at Rapid includes starting in Customer Service in 2015 and making the transition to sales in 2017. Her background in CS has helped her enjoy finding whole packaging solutions. This includes picking out stock options for short term use, to creating custom solutions unique to individual business and industries.

In her free time Jenny enjoys going to concerts - particularly country, pop and rock. She is a die-hard Minnesota Vikings fan and enjoys canning her own food in the fall (her favorite is homemade spaghetti sauce).

Jenny is National Bulk Bag's resident food-grade specialist. This includes but is not limited to pet food, nuts and legumes, and ready-to-eat foods. She understands in depth the stringent rules facing the food industry as a whole and is an expert at helping food companies find the right bag for their product and application. She also has extensive knowledge of woven polypropylene, BOPP, polyethylene, and textile bags.

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We stock one of the largest FIBC Bulk Bag inventories in the United States. Whether you are packing chemicals, food, minerals, resin, sand, soil or any dry flow-able product, we stock or can manufacture a bag to meet your requirements.

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