Polypropylene (PP)

Polypropylene (PP) is the second most widely produced plastic in the world and one of the most versatile engineering materials available. Its exceptional chemical resistance, low density (the lightest commodity plastic at ~0.90 g/cm³), and excellent fatigue resistance make it ideal for living hinges, storage containers, and piping systems. PP offers a unique combination of semi-rigid structure with good impact resistance at sub-zero temperatures, and it maintains its mechanical properties through repeated sterilization cycles — a property that has made it the dominant material in medical and laboratory equipment.

Mechanical Properties

• Density: 1.20 g/cm³
• Tensile Strength: 65 MPa
• Yield Strength: 60 MPa
• Elongation at Break: 120%
• Flexural Modulus: 2,300 MPa
• Hardness (Rockwell): R 70 (M scale: M70)
• Heat Deflection Temperature: 130°C @ 1.8 MPa
• Melting Point: 260–310°C
• Thermal Conductivity: 0.19 W/m·K
• Coefficient of Thermal Expansion: 6.5 × 10⁻⁵ /°C
• Water Absorption: 0.12%
• Flammability Rating: V-2 / V-0 (UL94, varies by grade

Advantages

🟢 Outstanding chemical resistance — resistant to acids, alkalis, and most organic solvents at room temperature

🟢 Extremely low density; lightweight advantage reduces part weight and shipping costs significantly

🟢 Excellent fatigue resistance — maintains mechanical integrity through millions of flex cycles, ideal for living hinges

🟢 Superior moisture barrier properties; virtually zero water absorption

🟢 Food-safe and FDA-compliant grades widely available; resistant to bacterial growth

🟢 Excellent electrical insulating properties; high dielectric strength

Machining & Manufacturing

Common Applications