Heat attacks a label in three separate places: the adhesive softens and oozes or lets go, the face stock shrinks or yellows, and the printed image fades or chars. A construction can perform differently in each respect. Agree the test items and acceptance criteria for the selected label.
Method
| Item | Condition |
|---|---|
| Substrate | Customer’s own substrate wherever possible; otherwise stainless steel or the specified plastic |
| Dwell before exposure | Conditioning time, temperature and humidity are agreed in the test plan |
| Exposure | Target temperature, duration and cycle are agreed for the application |
| Assessed after exposure | Edge lift, adhesive ooze and residue, dimensional change, discolouration, print legibility, barcode scan |
Selecting a construction for heat
| Application | What to confirm |
|---|---|
| Warm packaging or transport | Application and service temperatures, duration, substrate and adhesive. |
| Equipment and industrial use | Peak temperature, heat cycles, chemicals and legibility requirements. |
| PCB assembly | Full process profile, material specification and barcode requirements; review polyimide options. |
Material choice and temperature performance must be verified for the complete construction. Peak temperature, exposure time, cycles and handling conditions all matter; an oven range is not a label rating.
What to tell us
- Peak temperature and how long it is held
- Number of heat cycles over the product’s life
- Application temperature — labels are often applied cold and heated later
- Substrate material and surface condition, including any oil or release agent
- Whether the label must stay scannable after exposure
Related: Polyimide labels · Engine oil labels · Label Laboratory