Microwave-Safe Plastic Containers: What the PP 5 Recycling Symbol Really Means

📅 Oct 20, 2026 👁 views

Restaurants, meal prep brands and retailers are asked the same question every day: can this container go in the microwave? The answer depends on the resin. This guide explains what the PP 5 recycling symbol means, why polypropylene is the default choice for microwavable food containers, and how to verify a supplier's claims before you order.

What the number 5 (PP) means

The triangle with a 5 inside identifies polypropylene (PP). Among common packaging plastics PP has the highest melting point (about 160 °C) and a continuous service range of roughly -20 °C to 120 °C. That is why PP, not PET (1) or PS (6), is used for reheating-grade lunch boxes, soup bowls and meal prep containers. PET softens at about 70 °C and polystyrene becomes brittle in the freezer and can deform in the microwave.

Microwave, freezer and dishwasher icons

Microwave waves icon: the body and lid have been tested for reheating without warping or releasing substances beyond legal limits.
Snowflake icon: freezer safe, typically to -20 °C without cracking.
Dishwasher icon: reusable grades such as thickened or heavy-duty PP boxes survive repeated washing cycles.

Icons should be moulded into the base or printed by IML, not stuck on as a label that can wash off.

Is PP BPA-free?

Yes. Bisphenol A is used in polycarbonate and some epoxy coatings, not in polypropylene. Our EU test reports to (EC) No 1935/2004 and (EU) No 10/2011 nevertheless include a BPA screen to give importers documentary proof.

Food-contact testing you should ask for

Overall migration in 3% acetic acid, 10% ethanol and olive oil at 70 °C / 2 h (microwave simulation).
Specific migration of heavy metals and primary aromatic amines where pigments are used.
Sensory test for taste and odour transfer.

A trustworthy PP food container factory supplies these reports per material grade and colour masterbatch, not just a generic certificate.