Quick answer: PP is the default for wet food lines because it resists cleaning chemicals well and costs the least. POM (acetal) is the choice when belt pull is the limit, because on the same module it carries roughly two to two and a half times what PP carries, for example 12,300 N/m in PP against 31,100 N/m in POM on the 1100 series. PE is a niche pick for impact and cold, not for strength. "Food grade" describes the material and its compliance with food-contact regulations, not a certificate that belongs to the finished belt.
What "food grade" actually means
This phrase gets used loosely, and buyers pay for the confusion. Food-contact regulations apply to a material: a resin grade, its additives, its colourants. They are written for the substance that touches the food. A conveyor belt is an assembly of modules, rods, sprockets, flights and side guards, and an assembly does not hold a food-contact approval the way a resin grade does.
So the useful question is not "is this belt food grade". It is two questions. Which regulation are we working to, and which material grade is being supplied against it. A serious answer names both. Food-grade material options compliant with FDA and EU regulations are available across the belt range, and the grade actually used should be written into the order, not assumed from a catalogue line.
Watch out for the parts around the belt as well. Hinge rods, flights and side guards touch product too. If the belt is specified in a food-grade grade and the rods are not, the specification has a hole in it.
The three materials side by side
| Property | PP (polypropylene) | PE (polyethylene) | POM (acetal) |
|---|---|---|---|
| Belt strength position | Baseline | Lowest of the three, not normally quoted for high-pull duty | Highest, roughly 1.7 to 2.5 times PP on the same module |
| Acids and cleaning chemicals | Good, the usual reason it dominates washdown lines | Good | Weaker against acids and acidic cleaners |
| Fats and oils | Good | Good | Good, and it does not soften the way softer resins can |
| Low temperature | Stiffens and loses impact strength as it gets colder | Stays tougher when cold, the reason it appears on freezer lines | Stays hard and dimensionally stable, but is less forgiving of impact |
| Wear and surface hardness | Moderate | Lowest hardness of the three | Hardest, lowest sliding wear |
| Cost position | Lowest | Low to middle | Highest |
What POM actually buys you
The honest way to answer this is to look at the same module offered in both resins. The geometry is identical, so the difference in the quoted belt strength is the resin talking and nothing else.
| Series | Pitch | Belt strength, PP | Belt strength, POM | Gain |
|---|---|---|---|---|
| 926 flat top | 12.7 mm | 9,500 N/m | 21,200 N/m | +123% |
| 1100 flat top | 15.24 mm | 12,300 N/m | 31,100 N/m | +153% |
| 5935 flat top | 19.05 mm | 11,800 N/m | 20,700 N/m | +75% |
| 1000 flat top | 25.4 mm | 16,700 N/m | 39,300 N/m | +135% |
| 986 flat top | 25.4 mm | 18,056 N/m | 30,851 N/m | +71% |
| 7705 flat top | 25.4 mm | 23,300 N/m | 52,800 N/m | +127% |
| 900 flat top | 27.2 mm | 17,500 N/m | 40,300 N/m | +130% |
| 2400 radius | 25.4 mm | 17,000 N/m | 31,800 N/m | +87% |
| 7100 radius | 25.4 mm | 24,200 N/m | 30,900 N/m | +28% |
| 916 radius | 25.4 mm | 14,200 N/m | 14,700 N/m | +4% |
Two things fall out of that table. On straight-running modules, paying for acetal roughly doubles the pull the belt can take, which is a real answer to a long or heavily loaded conveyor. On the 916 large radius belt it buys you almost nothing, 14,200 against 14,700 N/m.
That is not an error in the data. The 916 module has 60% open area and turns inside 1.7 times the belt width, the tightest turn in the radius range. Cutting that much material away for the slots and the turn leaves a thin cross section, and a thin cross section fails before the resin is anywhere near its limit. Where geometry is the constraint, changing the resin does not move the number. Specify 916 in POM for its hardness and wear behaviour if you want, but do not pay the acetal premium expecting extra capacity.
Where each material belongs
PP is the sensible default on a washdown food line. It handles the caustic and acid cleaning cycles those lines run, it is the cheapest of the three, and on most conveyors the belt pull never gets close to its rating. The whole straight running belt range is available in it.
POM earns its place in three situations: long runs or high product loading where PP would be working too close to its rating once the belt pull is calculated, high line speed on a hard sliding surface where wear decides belt life, and lines that need tight pitch and high strength at the same time. Note the compromise. Acetal does not like acids, so on a line washed with acidic descalers or handling acidic product, a POM belt can be the wrong answer even when the strength calculation likes it. Acid-resistant PP grades exist for genuinely aggressive chemistry, which is why the acid environment mesh belt is built in PP and PE rather than acetal.
PE is the smallest of the three markets. It stays tougher in the cold than PP, which is why it shows up on freezing and chilling lines, and it is more forgiving of impact. It is also softer, so it wears faster, and belt strength figures are not normally quoted for it in the way they are for PP and POM. Treat PE as a cold and impact decision, never as a strength decision.
The parts people forget to specify
| Component | Usual material | What to confirm |
|---|---|---|
| Belt modules | PP, PE or POM | Which grade, and against which food-contact regulation |
| Hinge rods | Nylon 4.6 mm or PP 7.8 mm | Rod material is a separate choice from module material |
| Sprockets | POM (acetal) across the range | Sprockets are acetal even under a PP belt, so acid exposure at the drive matters |
| Flights and side guards | PP or PE | They touch product, so they belong in the same specification |
One more point that only shows up after installation. The three resins expand at different rates with temperature, and PE moves the most. If you switch a belt from PP to PE for cold performance, the frame clearance you designed for PP is no longer the right clearance. The thermal expansion guide has the coefficients and the worked calculation.
What to send with the enquiry
- The product being conveyed, including whether it is acidic, fatty or abrasive
- Belt width, conveyor length and line speed
- Product temperature and the cleaning cycle temperature, which are often the two extremes that decide the material
- The cleaning chemistry used, by type at least: caustic, acid, or chlorine based
- Which food-contact regulation your customer or auditor works to, so the material grade can be matched to it
Send those five items to the contact form or by WhatsApp, and you will get back two options with the trade-off written out: which series in which resin, and what each one costs you in strength, wear life and money. If you are still choosing the belt style rather than the material, start with the belt selection guide.
