High Strength Polybags

What makes a polybag high strength?

Strength in a polythene bag comes from more than thickness. Gauge matters, and high strength polybags are made from 100 to 250 micron film rather than the 30 to 50 micron used for light packing, but the film formulation matters just as much. Because we extrude our own film in Blackburn, strength, elasticity and stiffness are specified alongside thickness rather than taken as they come.

A bag that has to absorb a knock wants elasticity so it stretches instead of splitting. A bag holding a sharp casting wants puncture resistance and a stiffer film. A bag that has to hold its shape on a pallet wants stiffness. Tell us what the bag carries and how it fails today, and the film is specified around that.

What gauge do I need for a heavy or sharp product?

Gauge is the starting point on a heavy duty bag. For a heavy but smooth product, such as dense powder, granules or a solid moulded part, 100 to 150 micron usually holds up. For anything with corners, edges, exposed fixings or swarf, 150 to 250 micron gives the film enough body to resist a puncture rather than tear away from a small nick.

We manufacture high strength polybags across the 100 to 250 micron range. If you are replacing a bag that keeps splitting, send us a sample and tell us the weight of the contents, how far the bag is lifted or dropped, and where the failures start. That is far more useful than a gauge figure on its own.

Where do heavy duty bags usually fail?

Heavy duty polythene bags rarely fail in the middle of the film. They fail at a seal, at a corner where the load concentrates, or at a nick in the edge that spreads under weight. A bag splitting along the bottom seam usually needs a stronger seal or a gusset so the load spreads. A bag getting punctured needs a tougher film rather than simply a thicker one. A bag tearing from the top when lifted needs more elasticity.

Knowing where a bag gives way tells us what to change. We extrude and convert in house, so the film properties and the bag construction can be altered together rather than moving you onto the next thickest item on a shelf.

How are high strength polybags supplied?

High strength polybags are supplied flat, boxed or on pallets, in counts that suit your packing area. Because the film is much heavier than a standard bag, quantities per box are lower and pallets are heavier, so it is worth telling us how the bags are moved and stored at your end when you order.

Bespoke specifications typically take 2 to 3 weeks to manufacture, and repeat orders of a specification we have already run are quicker. Minimum order quantity depends on the size and gauge, and we confirm it when we quote. One-off trials are possible if you want to prove a bag before committing to a standing order.

Common applications for high-strength polybags

• Engineering components with sharp edges
• Castings, fixings and fasteners
• Aggregates, powders and granules
• Builders merchants and construction materials
• Automotive parts and spares
• Machine waste and offcut collection
• Compost, bark and heavy horticultural products
• Distribution of dense or awkward goods

Questions

High-strength polybags FAQs

How much weight can a high strength polybag hold?

There is no single figure, because it depends on the gauge, the bag dimensions, the shape of the contents and how the bag is lifted. A compact, smooth load in a correctly sized bag puts far less strain on the film than the same weight rattling around in an oversized one. Tell us the weight, the shape and how the bag is handled, and we will specify a gauge and construction for it. Where the load is critical, a trial run is the sensible way to prove it.

What is the difference between a high strength polybag and a standard polythene bag?

A high strength polybag is made from 100 to 250 micron film, where a general purpose polythene bag often starts around 30 micron. The heavier film resists puncture and tearing, which is what sharp, dense or awkward contents need. The film can also be formulated for strength or elasticity rather than simply made thicker. If your current bags split at the seams or get punctured in transit, that is the difference you are looking for.

Do heavy gauge bags affect my Plastic Packaging Tax position?

Plastic Packaging Tax applies to plastic packaging components that do not contain enough recycled content, and it is charged by weight, so a heavier gauge bag carries more tax per bag than a lighter one where it falls in scope. Raising the recycled content of the film is the usual route to change that, and we can quote recycled options where they suit your specification. Current rates, thresholds and rules are published on gov.uk, and your own position is worth confirming there or with your accountant.

Can a high strength polybag replace a cardboard box?

Sometimes. For dense, non-fragile items that need no rigid protection, a heavy gauge bag takes up less storage space and less weight than a box. Items needing corner protection, crush resistance or a flat stacking face still need a box, though a heavy gauge liner inside one is common. A trial run is the honest way to find out, and we support one-off trials.