How TPU cable carriers perform in heat and oil mist
Whether a TPU carrier handles heat starts with polyester-based versus polyether-based. The two lean in opposite directions on oil, hydrolysis and cold; pick the wrong side and a 120 C rating will not save it.
Ask whether a TPU carrier handles heat and an answer of "up to 120 °C" is close to useless. TPU is not one material but a family: polyester-based and polyether-based grades differ sharply in heat, oil and hydrolysis resistance. Pick the wrong side of that line and 120 °C will not save the application.
This article sets out where TPU carriers belong and where they do not.
First: polyester-based or polyether-based
Thermoplastic polyurethane splits into two families by soft-segment chemistry, and their performance leans in nearly opposite directions:
| Type | Oil and abrasion | Hydrolysis | Low temperature | Typical use |
|---|---|---|---|---|
| Polyester-based | Good | Poor | Moderate | Oil mist, coolant |
| Polyether-based | Moderate | Good | Good | Damp, warm water, outdoor, cleanroom |
That distinction gets skipped constantly in real projects. A polyester-based TPU in a hot, humid environment hydrolyses: the surface whitens, turns tacky, then cracks, and the part is gone in months. Polyether-based does not, but gives up some oil and abrasion resistance.
So the first question in selection is: is there persistent moisture or condensation? Yes means polyether. Pure oil mist means polyester is the better fit. Both together means a trade-off, or a different approach.
TPU against glass-fibre reinforced nylon
| Property | PA66 + 30% GF | TPU |
|---|---|---|
| Stiffness | High | Low, noticeably soft |
| Abrasion | Good, but sheds particles | Good, deforms around grit |
| Oil resistance | Moderate | Good |
| Low temperature | Brittle below about -30 °C | Flexible to about -40 °C |
| Particle emission | Continuous under dry friction | Low |
| Noise | Pronounced impact noise | Clearly lower |
| Load and span | Strong | Weak |
That table is why both product lines persist: nylon carries load and spans, TPU handles low emission, low noise, oil and cold. Neither replaces the other.
A common misjudgement: seeing TPU's abrasion figures and using it to replace a long-travel nylon carrier under load. TPU's elasticity is an advantage at light load and a liability at heavy load — links deform, the span sags, and the chain runs off track.
Heat: what the number means
The nominal range is usually quoted as -20 °C to +120 °C. Read it carefully:
- 120 °C is a short-term peak, not a continuous working temperature. Run there continuously and the material ages faster, hardness rises, elasticity falls, and fine cracks appear at the flex points first
- Keep continuous duty below about 80 °C; above that, derate the load capacity
- Heat plus load is non-linear — a 20 percent higher temperature does not cost 20 percent of life, it can cost half
Glass-fibre reinforced nylon holds up better over sustained duty below 100 °C. For continuous heat near oven exits or hot-press equipment, nylon has more margin.
The dangerous spots are the ones that do not feel hot: motor housings, the side of heater bands, next to welding stations. Ambient readings there are modest while radiant heat on the chain is high. The way to know is a thermocouple on a link through a full shift, not a shop-floor thermometer.
Oil: an advantage, with two caveats
TPU genuinely resists oil. Cutting fluid, hydraulic oil and way lube cause little swelling and no softening. Two things to watch:
First, oil with water in it. Emulsion and water-miscible coolants are oil-water systems. For polyester-based TPU, hydrolysis risk and oil resistance exist at the same time, and in practice hydrolysis usually wins. Prefer polyether here, or accept a shorter replacement interval.
Second, oil carrying grit. Cast iron swarf and grinding dust suspended in oil embed in the TPU surface. Because the material is elastic, the particle stays trapped and keeps scoring the sliding faces. In that case add a guard, or specify a version with a wiper geometry.
Three tests that decide it
Test one: are emission and noise hard requirements? Yes — cleanroom, medical, equipment close to operators: the TPU value is immediate. No — inside a machine enclosure where noise is contained and dust is irrelevant: nylon is the better buy.
Test two: is there persistent moisture? Yes — polyether grade, confirmed by name with the supplier. No — the polyester grade's oil and abrasion advantage applies.
Test three: what load and travel? Above about 3 kg/m of cable, or travel beyond four metres with unsupported span: TPU is wrong, go back to the heavy nylon range. Short travel, light load, high cycle rate: TPU's elasticity absorbs the impact.
If any one of the three points to "unsuitable", do not force it.
Four field mistakes
One: standard cable in a TPU carrier. The chain gets quiet, the cable bounces in the channel, and the noise comes out of the cable instead. Pair TPU carriers with flexible carrier cable.
Two: using nylon support spacing. TPU is softer and sags more over the same span. Support points need to be closer.
Three: greasing it. TPU links are self-lubricating. Grease attracts dust and accelerates hydrolysis in polyester grades. In a cleanroom it is out of the question.
Four: treating cold performance as universal. Flexibility at -40 °C is not the same as operating at -40 °C. On cold starts, run slowly for a few cycles and let the material warm.
Summary
A TPU carrier is not an upgraded nylon carrier. It solves four things nylon cannot: low emission, low noise, oil resistance and cold flexibility. The price is stiffness and load capacity.
Answer three questions first — are emission and noise hard requirements, is there moisture, what load and travel. Only then discuss grade and price.
To check a material against your duty, send the medium (oil, water, coolant), the temperature measured on the link, and the cable list. The full material comparison is in nylon, TPU or steel, cleanroom duty in the cleanroom selection guide, or contact us.