Bulk Bag Liners (Poly Liners): Layflat Liner-Form Fit Liner -Baffle Liner-Aluminium Foil Liner - Tubular Liner
Types of Liners Polyethylene liners, commonly referred to as poly liners, are flexible plastic liners specifically designed to line the inside of a flexible intermediate bulk container (FIBC or bulk bag). They not only provide additional protection for the contents of the bag, but also prevent certain materials from leaking out of the bag.
Poly liners are commonly used in industries when the following materials are stored and transported:
Chemicals
Fine Powders
Food and food products
Pharmaceutical materials
Sensitive materials
Types of Liners:
Lay-flat liners
Lay-flat polyethylene liners are the most common type of liners. They are cylindrical in shape, open at the top, and heat sealed on the bottom. If the liner is heat sealed it must be cut to discharge the product. Lay-flat liners often come pre-inserted into the bag or can be purchased separately in rolls and inserted after purchase.
Some other features of Lay-Flat liners include:
Oxygen barrier
Moisture barrier
Chemical resistance
Anti-static properties
High strength
Form-fit liners
Form-fit bulk bag poly liners are specifically designed to take the exact form of the bag including the spout inlet and outlet. Form-fit poly liners improve the bag’s performance and protect the contents from contamination during processing, storage, and transportation. Form-fit liners also allow for consistent fill and discharge of products because they do not have folds, pleats or other traps to slow down product flow. These liners can either be permanently attached to the bag or easily removed after each use. Form-fit liners have the exact same benefits and features as lay-flat liners (oxygen barrier, moisture barrier, chemical resistance, anti-static properties, and higher strength).
Baffle liners
The form-fit baffle design can provide superior package performance and, at times, reduce storage and shipping costs. The baffle liner is form fitted to the outer container and makes use of internal baffles to maintain the square shape. They also prevent the outward push of the product being packed that would normally result in a rounded bag when filled. The square shape of baffle poly liners can also help save space on pallets and in trucks.
Some other features of baffle liners include:
Increased bag stack-ability
Increased stability
Can hold up to 30% more product in a given space
Protection from contamination
Formed spouts for filling and discharge
Aluminum foil liners
Form shaped aluminum liners, also known as foil liners, improve filling, discharging, handling and stability of the outside of the bag. Foil liners offer great moisture, oxygen, and UV protection and are compatible with a wide variety of bags. Foil liners are made of aluminum-laminated films that protect the quality and the integrity of the product that is packed in the bag. Each foil liner can be manufactured using various aluminum compounds depending on the specific needs of each application.
Some other features of foil liners include:
Oxygen barrier l Moisture barrier
Chemical resistance
Anti-static properties
High strength
Tubular liners
Tubular liners are very similar to standard gusset liners in many ways. They are made of the same polyethylene material and are pre-inserted into the bag before leaving the manufacturing facility. The largest structural difference between the two is the opening at the bottom of the liner. In a standard gusset liner, the bottom of the liner is sealed shut. When discharging a bag, this liner is pulled through the bottom of the spout and cut allowing discharge to take place. In a tubular liner, there is no bottom seal to cut. During manufacturing, the end of the liner is fed through the spout before the bag is tied and there is no need to cut the liner when discharging.
Pre-lined bulk bags
Companies can purchase poly liners for bulk bags and insert them into pretty much any FIBC. However, you can also purchase bags that come with liners already built into the woven polypropylene. The biggest advantage to purchasing pre-lined bags is the variety of options available. Customized specialty and form fit liners are often not sold in rolls, making them only available in pre-lined FIBCs. Having these different options allows lined bags to be used with a greater variety of products and applications. One disadvantage to using pre-lined bags is that the liners may be either sewn into the seams of the bag or tabbed to the bag's material and cannot be removed. This offers slightly less flexibility as the liners can not be easily removed if your application requires it.
