Hours on a spec sheet are easy to print and hard to hold: the figure travels, the test behind it rarely does. The core is matched to the hours the brief names and the liner is closed by a weld, not a stitch — both settled on one sample in seven days, and the run repeats what the sample signed.
Cooler bag types
A soft body that packs flat, a rigid tub that stacks, a pack on two straps, a wheeled box for a long haul, a divided case for bottles — the shape a cooler bag takes is the first thing a buyer names. What is not here is still workable: the pattern is drafted from the sketch or the reference bag the same way.
The core
The fabric decides how the bag looks; the foam decides how long a cooler bag holds the cold. Two cores cover the range — a day-use sheet and a thick closed-cell build for a multi-day claim — and both buy a window a brief can be written against.
12–24 hcold held
PE or EPE closed-cell sheet, 5–15 mm
48–72 hcold held
NBR/PVC closed-cell core, 15–25 mm, over a radiant barrier
How the window is measured
Ice to payload at two to one by weight, chilled load — so two builds can be compared on one number.
A thermocouple sits in the middle of the payload, the slowest point to warm, logged every five minutes.
A constant 32 °C, or a day/night cycle of 28 °C then 38 °C, so a claim is tied to a condition, not a mood.
The run ends when the payload crosses 7.2 °C — the curve, not a marketing headline, is what ships.
The welded shell
How long the cold lasts is the foam's job; whether the melt stays inside is the seam's. An airtight soft cooler is a liner welded to itself, a closure seated in welded ends, and a pressure test no unit leaves the floor without passing.
The inner film is fused to itself, so no needle line runs through the liner for liquid to follow. A stitched seam wicks within a season; a weld removes the path outright.
The closure is a back-to-back airtight zip, and it fails hardest at its two ends, where the track meets the film. Both carry a welded patch that keeps the track from peeling away under load.
The base and sides are formed so the cross-seams land on doubled film. A gusset join is the second place a soft cooler leaks, and the doubling there stops a full bag weeping at the corner.
The leak gate
Where a cooler leaks first
Shell and lining
The build is a handful of films stacked and sealed: a coated shell that sheds water, a core that slows the heat, and a lining the melt sits against. All three are chosen for a job, and the jobs come apart when a cooler bag brief squeezes the cost.
Cooler brief to quote
Name the format, the hours and the quantity. Back comes the core to match them, the welded shell, and a sample at a hundred pieces.
Strengths and limits
The rows below pair what this floor does best with what it turns away on a cooler bag brief. Read the right-hand column first — a soft un-insulated bag, a stitched body or a run under a hundred does not fit this line.
| Spec | Where this floor is strongest | Where it does not fit |
|---|---|---|
| Insulation | A graded core — PE, EPE or NBR/PVC — picked against the hours the bag has to hold, not one sheet of foam for the whole range. | A plain un-insulated soft bag isn’t built here: the nine formats on this page are all closed-cell insulated and welded. |
| Leak integrity | An HF-welded liner with an airtight closure, and a pressure-decay gate cleared before a run leaves the floor. | A stitched construction isn’t taken — a sewn seam cannot hold a pressure test, so a stitched soft bag has no gate to show. |
| Decoration | A print that survives a cold, wet face, or a welded and embossed badge fixed to the film — whichever the condensation leaves intact. | Hairline type and fine line detail are not run as the main mark on a cold face; the print blurs there, so the mark moves to a badge or a stitch. |
| Order floor | A hundred pieces per construction, and a single approved sample in seven days before the run is committed. | A run under a hundred pieces isn’t scheduled, and a complex or unusual structure carries new tooling and a longer lead. |
A brand that needs welded, insulated construction, a core chosen to an hour figure, a leak gate on the run, and a hundred-piece test before a season.
A brief that wants a plain un-insulated soft bag, a stitched body, fine-line print on a cold face, or a few dozen units to try first.
R&D and capacity
A range is only as good as what stands behind it. This is the team that designs the formats, the equipment that cuts and forms them, the welding that closes a liner, and the throughput the lines turn out.
Buyer accounts
From the original cooler runs — a gifting brand and an outdoor label — and what the bag had to hold once it was out of the factory.
Emily JohnsonProduct Manager, EcoBrand SolutionsA branded cooler carries a client's name, so the brief opened on the hours it had to hold. The first cut ran a thin sheet core that quit by mid-afternoon.
The core fixed it: a closed-cell build on the day-use tier, walked to its 24-hour edge and signed off against the protocol, with ice to a ratio and a probe at the payload centre.
The seam came next: a foil lining welded to itself leaves no needle line, and the ends that wept now clear the 2.0 PSI gate on 100% of units. A hundred pieces, three seasons shipped.
Michael AndersonSourcing Director, Outdoor Adventures Inc.An outdoor label sells a cooler on one number: how long it actually holds. The range spans both tiers — a PE/EPE body for the commuter line, a 15 mm NBR/PVC build for trips.
The extended build is tested hardest, the welded shell held to the leak gate — a soft cooler weeping at a gusset corner is a return, and a return on a trip bag is the worst kind.
Material followed the hours: a coated weave that sheds spray, a lining picked for the film the melt meets. The bulk run repeated the sample to the seam, so a reorder lands identical.
From the line
Cooler runs, samples and reorders — the same build, photographed the way the bag actually gets used.
Cooler bag questions
The questions that come up on most cooler-bag enquiries. Where a figure already appears in a section above, the answer points at it, never repeats it a second time down the page.
The trip the bag is actually for decides it, not the headline hours. A bag that goes to work and comes home at teatime is wasting money on a thick core, and a bag that holds a fishing day or a two-night trip cannot be built on a thin sheet at all. The core band above grades the two — what a core is good for and where it stops paying — and the choice is settled at the sample, against the hours the brief names.
By what the supplier does after the liner is welded, not by the word on the page. Water-resistant means the shell shrugs off rain; leak-proof means the liner holds liquid inside, which only a welded liner with a sealed closure does, and only an air test proves. Ask a supplier what a bag is checked against before it ships. A stitched bag has no such check to show; the weld section above states the gate this floor releases a run on.
Yes — and what a buyer ends up holding is proof for one lot, not a standing certificate. The food-grade card above sets out the limits the film is bought against and the report a retailer asks to see; what the answer turns on is that the report follows the film that actually went into the run, so a substitution partway through the order re-opens the question.
Only the carry. How long the cold holds is set by the core inside the wall, not by the shell’s shape — a soft body, a rigid tub and a wheeled build take the same welded liner on this range. The format is picked for how the load travels, the core for the hours the brief names — and the two are settled apart at the sample. A larger or heavier format does not buy a longer hold; only the core does.
Frost and condensation make the outer face a harder surface to decorate than a dry tote, because it runs cold and wet for hours at a time. A print sits on a coated shell and is the method most likely to lift at a fold or across a seam, while a welded or embossed badge is fixed to the film and shrugs off the condensation. Which method suits the build is settled at the sample and checked after a wipe, not only read off the artwork.
A welded or laminated liner is a film, and two film faces laid together under a warm container floor can stick at the panel — the one packing failure peculiar to this product. Bags are kept off one another’s faces, either interleaved or held open, and the carton is packed to the plan the sample was signed against, so a face that leaves the floor clean arrives able to open.
The conditions it was measured under, and the log behind it. The core band above names the protocol this floor logs to, so a claim can be checked against a method, not taken on trust — ask any supplier for the same. Two factories can print the same number off two different tests; the figure alone screens nothing.
Start a cooler run
The sketch, the hours the bag has to hold, the quantity it ships in. Back comes a manufacturable spec, the core chosen to those hours and a welded shell — and a sample in your hand before a unit is committed.
