Heat-resistant and chemical-resistant are not grades you can buy by name. Two labels both described as "heat resistant to 200 °C" can behave completely differently: what decides survival is peak temperature, how long it lasts, and what else the label meets. This guide covers reading a temperature claim, matching facestock and adhesive to the real exposure, and a decision table for specifying.
1. Why "heat resistant" is not one specification
A label survives a hot process as a system: facestock, adhesive and print must all hold. Failure appears in one of three places.
- Facestock distortion. Paper yellows and cockles; films shrink or curl at the edges past their dimensional limit.
- Adhesive failure. The label lifts at corners, slides, or leaves residue on removal — often the first thing to go, and why a "heat resistant" film still falls off.
- Print degradation. Direct thermal images darken or fade; thermal transfer ink softens; inkjet and laser toner can crack when the label flexes after cooling.
Ask which of the three the application stresses. A label on the cold outer panel of an oven door stresses only the facestock; one on a part washed after baking stresses all three.
2. Reading a temperature claim: peak versus continuous
Suppliers quote two numbers and buyers often read only one.
- Peak (short-duration) temperature — a brief excursion of seconds to minutes: reflow soldering, a flash dryer, a shrink tunnel.
- Continuous (service) temperature — where the label lives for hours, days or years: an engine bay, a heated vessel, a drying oven.
The gap is large. A film comfortable at 150 °C continuous may take 200 °C for seconds; a paper that survives a 30-second pass may not last an hour. Always ask for both numbers and state the duration you need — a figure without a duration cannot be verified.
3. Choosing by application
Work from the exposure, not the material name.
| Application | Typical peak / duration | Other exposure | Facestock to consider | Adhesive note |
|---|---|---|---|---|
| Reflow soldering (SMT) | short, seconds | flux, cleaning solvents | PI film | must survive the same excursion without oozing |
| Paint or powder drying line | moderate, minutes | solvent vapour | PET film, coated paper | check edge lift after cooling |
| Chemical drums and IBCs | ambient | splash, vapour, UV | PE or PP film | match adhesive to the drum surface and to spillage |
| Engine bay and exhaust parts | continuous, hours | oil, vibration, dirt | PI or aluminized film | high-tack and oil-tolerant |
| Outdoor equipment and signage | ambient, seasonal | UV, rain, temperature cycling | PET film, synthetic paper | UV-stable, low edge lift |
Film covers most of this range: PET film labels for the general-purpose option, PI film labels where continuous high temperature and electrical insulation are both required. If the label's main job is electrical rather than thermal, start from the insulation labels family.
4. Chemical exposure is the second variable
Heat and chemistry interact: a solvent harmless at 20 °C attacks faster at 80 °C, and a film softened by heat is easier to penetrate. Screen on the chemical first, then confirm the temperature.
- Splash and occasional wipe-down — most film facestocks with a matching adhesive cope; the weak point is the edge, where liquid wicks under the label.
- Continuous vapour or immersion — a much smaller set survives; expect to move to PI, PE or a protective overlaminate.
- Oils and fuels — check the adhesive separately; oil tolerance is a distinct specification from heat resistance.
Where a chemical is named, put the name, concentration and contact time in the enquiry. "Chemical resistant" alone cannot be answered.
5. Common misapplications
- Buying on peak temperature alone. A label rated for a ten-second excursion is specified onto a surface that runs warm all day.
- Assuming the facestock is the limit. Most field failures are adhesive or edge failures, not facestock burn-through.
- Forgetting the cool-down. Some adhesives that hold when hot fail as the assembly contracts — check after a full thermal cycle, not during it.
- Skipping the surface. The same label on painted steel, bare aluminium, polypropylene and powder coat behaves differently; the substrate belongs in the specification.
FAQ
What does "heat resistant to 200 °C" actually mean?
Not enough on its own. Read it as either a peak or a continuous rating with a duration attached; ask for both and confirm which one is quoted.
Can I use a paper label in a hot process?
For short, dry excursions, coated paper grades are often adequate and cost less than film. With moisture, oil or a long dwell time, film is usually safer.
Do I need PI film for high temperature?
Only when the temperature is continuous and the label also needs electrical insulation or dimensional stability. For brief excursions, a high-temperature PET grade is normally sufficient and costs less.
How should I test a candidate label?
Apply it to the real substrate, run the real process, and inspect after cooling: edges, corners, print legibility, removal residue. Only a full cycle on your own line transfers.
Browse the range
Start at the eco labels overview, or go to the high temperature labels family. The wider functional labels group covers waterproof, cold-resistant, flame-retardant and anti-static options. Send your peak and continuous temperatures, the duration of each, and the chemicals present, and a specification can be matched before samples are issued.