In industrial packaging, protecting contents from moisture, dust, and contamination is a constant challenge. One of the simplest and most effective solutions is the poly box liner — a loose-fitting LDPE bag that lines the inside of a box to protect contents during storage or shipment.
What Are Box Liners?
Box liners are polyethylene bags designed to fit inside standard cartons or custom-sized boxes. At M Plastics, we produce them on our in-house blown film extrusion lines, then cut them to size and package them flat for easy use.
They can be made in layflat or gusseted form depending on the box dimensions and contents. Gusseted liners suit wider bases and open square to fill the box, while layflat options work well for uniformly sized products.
How They’re Used
Box liners are popular in industrial and food service settings. Common uses include:
- Lining gaylords and bulk containers
- Protecting metal parts from moisture
- Separating food ingredients from cardboard
- Preventing powders or small particles from leaking
- Handling product returns or recycled material
Our liners are custom-made to match your box sizes and load weights. We use virgin or in-house reprocessed LDPE — never post-consumer waste — to keep the film consistent and clean.
Options Available
Box liners can be ordered with printing, color tinting for batch identification, or in VCI-treated LDPE film when metal protection is needed. Mil thickness is spec’d to the use case — lighter for dust protection, heavier for abrasive or heavy loads. Minimum order quantities and lead times vary based on width and film thickness.
Why It Matters
For operations handling heavy or delicate parts, skipping a liner risks contamination or corrosion — and the integrity of your product with it. Box liners are a critical first layer of protection in your packaging system.
Want liner options matched to your load sizes and packing flow? Request a quote and we’ll spec it together.
Have a Packaging Question?
M Plastics manufactures LDPE bags and film in Los Angeles with in-house extrusion and printing. Tell us what you're packaging and we'll help you spec the right bag.
Get a Quote