PP vs HDPE: which recycled plastic should you buy?
PlasticSetu sourcing desk · Updated 14 Oct 2026
Polypropylene (PP) and high density polyethylene (HDPE) are the two most traded recycled plastics in India. Both are polyolefins, both float in water and both often arrive as white or natural scrap. Mixing them up costs money, because each suits different products.
How they differ
| PP | HDPE | |
|---|---|---|
| Density | About 0.90–0.91 g/cm³ | About 0.94–0.97 g/cm³ |
| Melting point | About 160–165 °C | About 125–135 °C |
| Stiffness | Stiffer, holds shape at higher temperatures | Tougher and more flexible, very good impact at low temperatures |
| Typical recycled uses | Raffia and woven sacks, injection-moulded household items, crates, automotive parts | Pipes, blow-moulded cans and drums, crates, film |
| Common recycled forms | Raffia and woven-bag scrap, moulding regrind, granules | Blow and pipe scrap, drum regrind, granules |
Which one fits your product?
- Woven sacks, raffia, non-woven: PP. Ask for raffia-grade material with an MFI suited to tape extrusion.
- Pipes and irrigation: HDPE pipe grade with low MFI and carbon black for UV stability.
- Cans, drums and bottles: HDPE blow grade.
- Buckets, chairs, household moulding: PP injection grade, or HDPE injection grade where impact matters more than stiffness.
Quick checks to tell them apart
Both float in water, so the float test only separates them from PET, PVC and filled grades. In practice, buyers rely on the supplier's declaration, a melting-point or density check in a lab, and a trial run. PP feels harder and makes a sharper sound when tapped. HDPE feels waxier. Mixed PP and HDPE runs poorly and gives weak, brittle parts, so ask for the polymer purity in writing.
What to put in your requirement
State the polymer, form (scrap, regrind or granules), grade (raffia, injection, blow or pipe), colour, MFI range, monthly quantity and delivery city. The PlasticSetu desk then compares quotes from suppliers who actually have that grade.