L2 liners for Bulk Bags
By Jim Foster
October 1, 2016
At a recent FIBCA conference, the topic of L2 liners used in bulk bags came up in a panel discussion. I felt it was worth trying to share that information with you.
This brief overview will give you a basic background of the antistatic liners.
The L1 liner has at least one side of surface resistivity of .
The L2 liners have one at least one side of surface resistivity of .
The L3 liners have both sides of surface resistivity of .
L2 liners are allowed for use in Type B, C and D bulk bags that have electrostatic properties (They are a very popular choice due to their versatility).
However, the decision on the L2 liner makeup is dependent on the user's application and shelf life of the product packaged in the bulk bag. The choice will be between the migratory antistatic film and permanent antistatic film. Both films will meet the antistatic needs to avoid static discharges safely.
The migratory film is an attractive choice because of its lower cost. Be aware the agents that make the film antistatic are migratory (as the name states) and have a shelf life. The shelf life is approximately 12 months depending on environmental conditions. Please consider your needs when you are deciding on which film you need for your liners in antistatic bulk bags.
As part of the decision-making process ask your team the following questions:
Can the migratory agents affect my product?
If I am packaging a food additive or food product are the antistatic agents being used food safe?
Can I live with a 12-month shelf life from the date the film is manufactured?
When answering the last question, please take into consideration the timeline that may be very realistic when ordering your bags. The order is placed for your bulk bags. The film for the liners is scheduled and manufactured within two weeks of the order. The bags will take six weeks to produce. The film is now one-month-old before the bags are even completed. The bags take five weeks to transit the ocean and arrive at the warehouse's door. The film is now more than two months old before you can even begin to use them. If you release them out of the warehouse at a slow pace, the bags shelf life is dwindling away. If your product has a 12-month shelf life, you will fill the bags with no problem at your facility but by the time the end user (your customer) begins to use your product they are using anti-static bags and liners that will no longer work as the shelf life of the film has expired.
The permanent L2 anti-static film has a shelf life of up to 5 years. The levels of the extractable are much lower compared to migratory anti-static films. The cost of the permanent antistatic film is more expensive than migratory antistatic films.
A few questions to ask your team when evaluating the permanent antistatic films are;
Is the benefit of fewer migratory agents releasing and potentially contaminating your product a benefit?
Does the longer shelf life pose less risk to you or your customer for using expired antistatic films?
The permanent antistatic film in an L2 liner does cost more. But unless you and your clients are comfortable with the shorter shelf life of the migratory films and the migratory agents exposed to your products, we at Global-Pak feel the better choice is the permanent antistatic film for your L2 liners in your bulk bags.
I want to give credit and thanks to Raymond Joyner of Grayling, ILC Dover www.ilcdover.com/grayling-industries for his presentation at the FIBCA meeting www.fibca.com. I would also like to thank Brett Millman from Plascon www.plascongroup.com for previous conversations and contribution to my general knowledge of the antistatic liners.