Polythene Liners Slipping or Splitting? Checks Before Ordering Thicker Film
A liner that drops into a pallet box during filling can interrupt the job. A split liner can mean unpacking, cleaning up or rejecting a packed container. Ordering thicker polythene may sound like the obvious answer, but first establish where and when the failure happens.
At Stretchband Packaging, we recommend recording the container, liner and filling conditions together. The following checks are a practical starting point for industrial packers reviewing recurring liner problems.
Start with the failure, not the thickness
Keep an unused liner from the same batch and photograph a failed example before removing it. Record whether the problem starts during fitting, at the first product drop, near the end of filling or during movement. Mark the position of the damage relative to the container.
Separate a liner slipping below the rim from a puncture, a tear through a fold and an opening at a welded seam. These observations give your supplier a much clearer starting point than a report that the bag is not strong enough.
If the liner slips inside the container
Fit an empty liner and check whether its base reaches the bottom without pulling the folded-over section down from the rim. Look at each corner, then repeat the check as filling begins. Avoid judging fit only from how the liner looks in an empty box.
Record the container's internal length, width and usable depth, plus its rim shape and any taper. Include the make or model where available. Check several containers if your fleet contains different versions. A container's external dimensions are not a complete liner specification.
Ask operators to demonstrate their normal fitting method. Note how much material folds over the rim, whether a lid is used and how the liner is retained. Any clips or retention arrangement should be suitable for the container and process; do not improvise a change that introduces sharp contact points.
If the liner splits during filling
Inspect the empty container for rough edges, damaged corners, protruding fixings and trapped debris. Compare their locations with the damage on the liner. Then observe where the product first lands and whether the liner is dragged or trapped as filling continues.
Give your supplier the product's shape, approximate load weight, filling method and relevant temperatures. Include the drop height and whether the contents settle, compact or move during transport. These details help define the conditions the liner needs to withstand.
For damage close to a weld, retain a sample showing the full seam and surrounding film. A tear beside a seam and a seam opening are different observations. Avoid assigning a cause until the sample, dimensions and handling conditions have been reviewed.
Check the material needed above the fill level
A liner must accommodate the chosen closing method as well as the container. Demonstrate whether the top is folded over, tied, heat-sealed or tucked beneath a lid, and record the material available after filling.
Do not use a fixed allowance for every job. The required length depends on the container, fill level and closure. If a change in liner length is proposed, check both the base fit and the finished closure on a representative filled container.
Change one variable and compare the result
When the basic fit and handling checks are complete, agree a sample specification with your supplier. That may involve a dimensional change, a different construction or material, or a thickness change. Keep a record of exactly what differs from the current liner.
Run the comparison under the usual filling and handling conditions. Record the number fitted, slips, splits, refits and rejected containers. Include operator feedback on opening, fitting and closing. Agree acceptance criteria before deciding whether the new liner should replace the existing specification.
Compare cost per successfully packed container, including wasted liners and time spent refitting. A lower purchase price alone does not establish which option is more economical for your operation.
What to send when asking for help
Prepare a short pack containing container dimensions and photographs; current liner dimensions, thickness and material if known; a batch reference; an unused and a failed liner; product and filling details; the failure location; closure method; and approximate annual usage. State whether you need loose liners or a roll presentation.
Flag any food-contact or other application-specific requirements before choosing a material. Ask for confirmation for the exact proposed grade and conditions of use rather than relying on a general product description.
Discuss a liner review with Stretchband Packaging
We supply bespoke liners for pallet boxes, Dolavs, tote bins and other containers, with dimensions and presentation developed around the application. If your liners are slipping or splitting, send us the container details and a photograph of the problem. We can discuss the specification and whether a sample comparison would be useful.
