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What is PP (Polypropylene)?

Polypropylene (PP) is a thermoplastic polymer belonging to the group of polyolefins. Its properties are similar to those of polyethylene (PE) but differ due to the presence of a methyl group in the molecule, which gives PP higher rigidity, hardness, and thermal resistance. With a density of about 0.895–0.92 g/cm³, PP is the standard plastic with the lowest density, making it very lightweight.

The melting temperature is around 160–165 °C, and the recommended continuous use temperature ranges between +5 °C and +85 °C. Below +5 °C, PP may become brittle, while prolonged exposure to higher temperatures can affect its dimensional stability.

This range may vary slightly depending on additives and formulation. At room temperature, PP is resistant to fats, oils, water, alcohols, and almost all organic solvents, except for strong oxidizing agents. Non-oxidizing acids and alkalis can be safely stored in PP containers.

At elevated temperatures, PP may dissolve in certain solvents such as xylene, tetralin, or decalin. PP is virtually odorless, physiologically safe, and widely used in food and pharmaceutical packaging. It is also fully recyclable (recycling code 05) and among the most important packaging materials worldwide.

Polypropylene (PP) – Properties & Applications

Criterion Description Practical relevance
Material type Thermoplastic polymer from the polyolefin group; related to polyethylene (PE) but with an additional methyl group. Increased stiffness, hardness and thermal resistance compared to PE.
Density Approx. 0.895–0.92 g/cm³ Lowest density of all standard plastics – lightweight and resource-efficient.
Melting temperature Approx. 160–165 °C Well suited for thermal forming processes such as injection moulding or thermoforming.
Continuous service temperature Recommended: +5 °C to +85 °C Below +5 °C PP can become brittle; above +85 °C shape stability decreases.
Temperature behaviour Cold: brittle / Heat: softer structure Impact-sensitive at low temperatures; hot filling only within the approved range.
Chemical resistance Resistant to fats, oils, water, alcohols and most organic solvents.
Not resistant to strong oxidising agents.		 Ideal for many technical, chemical and food-related applications.
Acids & alkalis Good resistance to non-oxidising acids and alkalis. Suitable for safe storage of such media in PP containers.
Solubility at elevated temperature Soluble in certain solvents (e.g. xylene, tetralin, decalin) at elevated temperatures. Avoid contact with hot aromatic solvents.
Sensoric properties Almost odourless and physiologically safe. Very well suited for food and pharmaceutical packaging.
Recyclability Recycling code 05 (PP); fully recyclable. Actively contributes to circular economy; mono-material processing recommended.
Typical applications Pails, cups, lids, trays, technical parts. Versatile thanks to high stiffness and chemical resistance.

Note

For applications below +5 °C or above +85 °C, we recommend prior practical testing and material validation. Avoid media contact with strong oxidising agents or hot aromatic solvents.

Status: 2025 · Source: Bikapack Product Management · All information without guarantee.