Today’s topic is the “melting point.” It may sound basic, but as the name implies, this refers to the temperature at which a solid turns into a liquid.
The most familiar example is probably ice. Ice is solid. When you apply heat, it melts into water—a liquid. This happens at 0°C, which is the melting point of ice. As we all know, water becomes solid or liquid around 0°C. It’s such a common phenomenon that we don’t even think about it, but this is the definition of a melting point.
If we ended the article here, it would be far too short. So let’s go a little further and tie it into another important concept: heat resistance.
I’m sure many of you enjoy wandering around hardware stores or budget shops — I certainly do. There’s something fun about just browsing and seeing what’s out there. If you look closely at plastic products, you’ll often see labels like “Heat Resistant up to XX°C.”
But what does that temperature really mean?
In fact, there are several temperature-related indicators used for plastics, such as:
- Heat deflection temperature
- Glass transition temperature
- Continuous use temperature
- And of course, the melting point
So what does “heat resistance” actually mean?
You might be thinking, “Isn’t it just the melting point?”
Good guess — but no, it’s not about using plastic products right up to the point where they melt.
The correct answer is: “Continuous Use Temperature.”
For reference, here are some representative melting points:
| Material | Melting Point (approx.) |
|---|---|
| PE (Polyethylene, HDPE) | ~130 °C |
| PP (Polypropylene) | ~160–170 °C |
| PTFE (Polytetrafluoroethylene) | ~327 °C |
| PEEK | ~343 °C |
* Values may vary depending on grade and formulation.
Continuous Use Temperatures (Heat Resistance)
When it comes to continuous use temperatures — what we typically mean by “heat resistance” — the range also depends greatly on the type of resin.
Even among similar-looking products in budget shops, you may notice very different heat resistance values depending on the manufacturer.
So, how are these numbers decided? To be frank, the basis can sometimes be surprisingly loose.
Let’s take PP (polypropylene) products as an example.
One washbasin might be labelled “Heat-resistant up to 80 °C,” while another claims 100 °C — and occasionally, you’ll even see 120 °C or 130 °C.
In our industry, however, we would never state a heat resistance that high for PP.
When I see such numbers in shops, the engineer in me immediately thinks:
“That’s unrealistic.”
“There’s no way it would hold up at that temperature.”
I understand the temptation for manufacturers to present the highest possible value, but in many cases, it’s overly optimistic.
So, What About Our Plastic Bearings?
With our products, the heat resistance figures are based on precise testing and material specifications.
We prioritise realistic, reliable data — because performance in real-world conditions matters more than the number on a label.
These are even more sensitive than everyday consumer items, because external factors such as load and rotation come into play.
That’s why plastic bearings often can’t withstand the full heat resistance values listed in material manufacturers’ datasheets.
For example, if someone asks, “What’s the heat resistance of a PP bearing?”—we generally recommend a maximum of around 70 °C.
And even that is the upper limit. Depending on the applied load and speed, the bearing might not last even at 70 °C.
Plastic bearings are designed for specialised environments. Material selection requires experience and consideration of multiple conditions—not just temperature, but also mechanical and environmental factors.
So, dear readers, if you’re unsure which material to choose, please don’t hesitate to get in touch. We’ll be happy to listen and offer advice based on your application needs.
