Whether you’re looking for a standard liner or a custom form fit liner to put inside of your bulk bag, we have a solution for you. Our liners can be made with attachment tabs which allow you to sew, tie, or glue in the liner eliminating the chance of liner discharge. All liners can be made from a variety of materials to impart the performance you desire such as oxygen & moisture barrier, anti-static properties, chemical resistance, FDA approval, high strength and other uses. Here at Palmetto Industries we can all customize your liners to form fit you bulk bag/ FIBC dimensions. This form fit eliminates wasted space, stress points in the liner and allows the FIBC to fill evenly. Because the FIBC fills more completely, the package is more stable and stacks better.
- Containment and integrity of the product
- Protection of the surrounding environment
- Prevention of moisture (ingress) – dry products
- Control & prevention of air / gas migration
- Control aromas / tainting
- Enable suitable handling of liquids and semi-solids
- Prevent leakage of product
- Enhance outer package
- Electrostatic protection
- Tube stock – an extruded tube, open on each end.
- Bag Style – an extruded tube, heat sealed on one end.
- Gusseted form-fit – a liner that can be made from as many as 4 pieces heat sealed together and when inflated mimics the shape of the FIBC, can have a heat seal bottom.
- Form-Fit – a liner that has a body, top, bottom and spouts, all heat-sealed to make a concise bulk bag shaped liner that fits inside the bag, can have single or double discharge and heat seal.
- Baffle Liner – a liner built the same as a form-fit, but with heat sealed polyamide baffles inside the liner, can be used inside a large U- Panel, or 4-panel to give the appearance of and allow the performance of a Baffle bag.
Blown Film Extrusion Process
The blown film is produced to exact recipes and is then sent to liner divisions that form shape the liners to the proper specifications using heat sealing machinery
The weather resistance, light, gas, water vapor and aroma barrier properties have to be taken into account to meet the specific needs of the bulk product, along with the storage and transport conditions. The target is to maintain the chemical and physical properties of the product and to ensure protection against oxidation, dampness and loss of aroma.
|TEMP||Max Fill Temperature for product|
|MVTR||Moisture Vapor Transmission Rate|
|OTR||Oxygen Transfer Rate|
|LDPE (Low Density Polyethylene)||165||Poor||Poor||Poor||–|
|LHDPE (High Density Polyetehylene)||165||Fair||Poor||Poor||–|
|PP (Polypropylene)||285||Poor||Poor||Fair||Excellent Heat Resistance Puncture / Stretch|
|PNP (Polypropylene Nylon Polyetheylene)||230||Poor||Excellent||Excellent||Resistant Noxious Chemical|
|EVOH (Ethylene Vinyl Alcohol)||185||Poor||Excellent||Excellent||Resistant|
|PECLB (Polyethylene Carbon Loaded)||165||Poor||Poor||Poor||Conductive|
|ALU (Aluminum Foil / Polyethylene)||165||Excellent||Excellent||Excellent||Very Expensive Film|
These are just a few primary liner films.
Films can be co-extruded with
variety of poly
substances including nylon, polyamide, and rubber modified. There are also a variety of films available that have additives to reduce electrostatic discharge. The difference between low density and high-density materials concerns molecular compaction.
- Glued in liner A liner may be glued either at the top, bottom, sides or a combination of any or all. Gluing is the most secure liner attachment method to secure liner in place during fill and discharge
- Sewn Tabbed liner Reinforced tape tabs are attached on the top, sides, bottom or a combination of any or all. These tabs are sewn into the seams of the bag. This is the most popular secure liner attachment method.
- Sewn Flange Form-fit or Gusseted Liners may have a flange of liner film around the top, bottom, sides or a combination of any and all. These flanges are sewn into the seams of the bag, but should be used in conjunction with tape tabs at the top to keep the liner from tearing under the stress of filling or discharging product.
- Tie in Liner Strings or Laces are attached to the Liner much like the tape tabs, but liner is tied in, not sewn in. This allows for easy liner removal and replacement and is commonly used for reuse applications.
- Loose inserted Liners Liner is inserted into the bag without being secured to the bag body. The liner must be pre-inflated to insure Liner properly fills. This is the most cost effective insertion method.
- Taped in Liners Liner is secured in place with a double stick tape which usually runs the entire length of the seam.
- “Form Fit” liners, which are heat welded to fit the shape of the bag are sometimes fabricated so that there is a “lip” of the liner material either around the top, or down the vertical seams, or around the bottom or a combination of the above. Attachment is made possible by sewing the liner into the seams of the bags.
- Concern: Sew lines are usually 3 to 4 stitches per inch. The perforation of the liner in the process can create a “postage stamp” effect whereby the liner can tear away from the bag body. The friction created by discharging product can then pull the liner out of the bag with the liner being held in place inside the fill spout by the tied fill spout neck. Operators will sometimes loosely tie the fill spout negating what little holding benefit takes place. Some operators will double the fill spout over “swan-neck style” to more securely hold the liner inside the spout as a protective measure. If this is the type of form-fit liner that has a fill spout heat sealed onto a bag top (which is heat sealed onto a bag body) the stress is then placed upon the circumference of the heat weld where the liner spout joins the liner top and can potentially cause the liner body to pull free from the spout. The liner can then exit the bag unrestricted.
- “Bag type” liners or “Form Fit” liners which are held in place by various style tabs that are attached to the liner material itself. These tabs can be positioned at multiple points on the liner such as around the top and bottom and sometimes down the sides (most secure). Sometimes, tabs are only attached at 4 top points on the liner, which are sewn into the top of the bag body (least secure).
- Concern: The discharge stress from product friction leaving the bag can stretch the liner material at these tab attachment areas potentially causing the liner to rip free leaving the fill spout holding the liner with some of the same concerns listed above. A properly glued in bag liner has the benefits of more liner attachment in contact over a far, far greater area providing excellent “sheer” strength. You may have noticed that some liners that are glued in can be removed by pulling the liner away from the bag body. By a rule, glue does not have as much “tear” strength as a tab in a single point. Due to the dynamics of product discharge, tear strength is not as critical as sheer strength. When a glued in liner is pulled outwards with some effort, it can be removed from the bag body, but when a liner is pulled downwards it is a firm attachment method with substantially more holding power than a tab liner of any configuration.