A shipping label is read by machines at four or five points between the packing bench and the doorstep. It fails not when it is printed, but when it is rubbed, stacked, rained on, or stuck to a carton made of recycled board with a dusty surface.
Model guide · last verified 2026-10-21 · published in English · technical questions: contact the lab
The print stops scanning. Direct-thermal paper darkens by a heat reaction in the coating. An uncoated or poorly top-coated grade loses contrast when it is rubbed against other cartons, exposed to sunlight, or kept above 40 °C in a van. The label is still attached and still legible to a human, but the scanner rejects it — and that is a redelivery cost, not a material cost.
The label will not stick to the carton. Corrugate is a rough, fibrous, often dusty surface, and recycled board is worse: shorter fibres, more surface dust, sometimes a release agent from the board's own coating. A permanent adhesive designed for film will hold initially and let go in a cold warehouse.
The label lifts in the rain or the cold room. Water enters under a lifted edge. Paper facestocks absorb it; the label cockles and the barcode geometry changes.
Four properties, and they are usually traded off against each other without anybody saying so in the specification.
| Property | What it means in practice | What we look at |
|---|---|---|
| Barcode contrast retention | Grade holds after rubbing and a few days at 40 °C | Topcoat quality; direct-thermal chemistry |
| Initial and ultimate tack on corrugate | Holds at the packing bench and stays held in a cold warehouse | Adhesive type and coat weight; hot-melt for board |
| Facestock stiffness | Feeds through a high-speed applicator without curling or jamming | Paper grammage and liner caliper |
| Moisture tolerance | Survives a wet van without cockling | Facestock choice; paper vs film |
"Thermal paper" is three different products in a buyer's inbox, and the price gap between them is real because the top layer is doing real work. Ask which grade you are being quoted; the word "thermal" on its own does not answer it.
| Grade | What the top layer does | Where it still fails | Typical use |
|---|---|---|---|
| Uncoated thermal | Nothing over the image layer | Rubs off under handling, fades in sunlight, and darkens or loses contrast against PVC plasticiser | Same-day indoor picking labels where the label is read once and discarded |
| Top-coated (TOP) | A protective coat over the image layer; keeps contrast through handling, damp and ordinary grease | Prolonged solvent wipe-down and long contact with plasticised PVC can still get through | The default for 4x6 direct-thermal shipping labels and shelf labels |
| Three-proof | A topcoat formulated against water, oil and alcohol; some makers also qualify plasticiser and call it four-proof | Costs more, and needs the printer energy setting matched to the grade or the image comes up grey | Kitchen, food processing, chilled weighing stations, wipe-down areas |
We state the grade on the TDS rather than quoting a fade figure. Fade depends on printer energy, storage heat and how often the label is rubbed — a number measured in someone else's lab will not predict your route. Print a roll, put it on a real carton and read it with your own scanner at the end of the journey.
Three thermal grades and three paper grades cover most logistics work in our range. All are standard constructions with published TDS.
| Code | Facestock | Adhesive | Liner | Where it fits |
|---|---|---|---|---|
| FL0109W21 | 70 gsm thermal paper (top coated) | Hot-melt | 60 gsm white glassine paper | The default 4x6 direct-thermal shipping label |
| FL0110W21 | 70 gsm thermal paper (top coated) | Hot-melt | 60 gsm white glassine paper | Same family, different coat weight; keep one code in the specification |
| FL0111W21 | 70 gsm thermal paper (top coated) | Hot-melt | 60 gsm white glassine paper | High-volume runs where roll-to-roll consistency matters most |
| FL0101W21 | 70 gsm woodfree paper | Hot-melt | 54 gsm white glassine | Laser-printed or pre-printed paper labels, addressing and shelf labels |
| FL0102W21 | 100 gsm woodfree paper | Water-based | 54 gsm white glassine | Heavier paper for hand-applied labels and return paperwork |
| FL0204W21 | 50 mic glossy white BOPP film | Frozen | 60 gsm white glassine | Cold-store and chilled logistics where paper would cockle |
Direct-thermal paper is not for long-term archive use: the print will fade. Where a label has to stay readable for years, use thermal-transfer or pre-printed film.
Start from the printer, then the carton, then the journey. Anything else is guessing.
| If this is your situation | Start with | Because |
|---|---|---|
| Direct-thermal 4x6, high volume, next-day delivery | FL0109W21 — 70 gsm top-coated thermal | Topcoat keeps the barcode grade through handling; hot-melt holds on board |
| Labels printed weeks in advance and stored | Thermal-transfer on a film, or pre-printed paper | Direct thermal keeps developing with heat; a stored label can go dark or lose contrast |
| Chilled or frozen warehouse | FL0204W21 — 50 mic white BOPP, frozen adhesive | Paper absorbs condensate and cockles; film does not |
| Hand-applied on recycled cartons | FL0101W21 — 70 gsm woodfree, hot-melt | A softer, high-tack adhesive copes with dust and short fibres better than a firm film grade |
| Fanfold or high-speed applicator | The thermal family, then test feed | Feed behaviour is a liner and stiffness question — sample before committing |
Logistics complaints are usually quantified — a percentage of no-reads on a line. That is useful, because it tells you whether the problem is material or equipment.
Symptom: labels scan at packing and fail at the depot. Cause: direct-thermal print losing contrast to heat, light or abrasion — often an uncoated or lightly coated grade. Fix: move to a top-coated thermal paper, and keep printed labels out of direct sun and hot vehicles.
Symptom: labels on the floor of the trailer, or hanging by one edge. Cause: dust and short fibres on recycled board, plus a cold trailer. Fix: a hot-melt adhesive with higher initial tack, and better application pressure. This is the single most common logistics complaint we handle.
Symptom: labels peel off the liner in the magazine, or the web curls. Cause: stiffness mismatch between facestock and liner for that roll diameter and that machine. Fix: send us the applicator model and roll diameter; we will match a construction that feeds, and you should still run a roll before ordering a pallet.
Symptom: barcode runs and the label smears in rain. Cause: water reaching a direct-thermal coating. Fix: film facestock with thermal-transfer printing, or a protective varnish. Direct thermal on paper is not a wet-weather product, whatever the datasheet implies.
We do not print labels, and we do not sell printers. We coat and laminate the material. That means the honest answer to "will this scan on my printer" is: send us a roll, run it on your printer, and verify the grade with your own scanner.
It takes an afternoon and it eliminates the most expensive kind of argument — the one where the material supplier, the printer supplier and the applicator supplier each prove it is not their fault.
Answered by the coating and conversion team, not by marketing.
Cold-store logistics is a freezer problem wearing a shipping label.
Returnable totes and reusable crates need labels that come off, not labels that hold harder.
Feed behaviour on high-speed applicators is a liner question more often than a facestock question.
Cold chain, beverage, pharma, security and electronics in one index.
Tell us the printer, the applicator and the carton; we will send material to test.