When to Use a Polyethylene Liner

Working with sensitive materials and chemicals often creates a need to protect the product at all costs from even the smallest defects. Polyethylene liners, often called poly liners, are useful bag-lining tools used for just that purpose across a countless number of industries, including food and pharmaceutical companies. They are applicable in any job with sensitive bulk materials as a liner for flexible intermediate bulk containers (FIBC), or bulk bags.

What Are Polyethylene Liners for Bulk Bags?

These effective liners are flexible plastic designed to line a bulk bag and add an extra layer of protection for any application. Poly liners work to protect the bulk bag itself and the product inside. This is particularly useful to stop any leaks from occurring and prevent contaminates like dust and moisture from seeping inside the containers. Liners make bulk bags nearly impenetrable in many situations. Always make sure you have the right size liner that’s properly secured the top once the bag has been filled to avoid material, moisture and oxygen transfer rate loss.

When Should You Use Polyethylene Liners for Bulk Bags?

Bulk bags have individual strands of polypropylene interlaced to create a durable, lightweight, flexible fabric weave useful for the storage and transport of important substances. Without a liner, however, some issues can occur. Some instances when it becomes crucial to have a polyethylene liner include:

  • Use of chemicals: There is no such thing as a bulk bag that lasts forever. They are susceptible to natural wear and tear like any other material. However, they are designed to have a long lifespan if properly maintained, and that’s when polyethylene liners come into play. Certain chemicals can speed up bag deterioration, and liners protect against this rapid corrosion.


  • Fine powder containment: Fine powders can leak through the body and seams of a bulk bag while it is being filled and maneuvered. No matter what industry is using the bulk bag, product shrinkage can mean inaccurate measurements or lost profits. Polyethylene liners keep chemicals and powders safely inside the bulk bag until it is time to get them back out.


  • Industries with sensitive operations: When companies handle sensitive consumables like food and certain pharmaceutical products in bulk bags, it is imperative that the contents remain entirely pure from beginning to end. Polyethylene liners add a strong safeguard to make sure no mistakes are made in production.

At Midwestern Bag & Supply, we offer a large selection of packaging solutions, including bulk bags with polyethylene liners, in whatever sizes you need. We strive for perfection and never settle for anything less than excellence, so if you have any questions about polyethylene liners for any bulk bag, contact us right away for answers!

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