Polypropylene (PP)
Polypropylene (PP) is a light, low-cost plastic with excellent chemical resistance and better heat resistance than polyethylene, up to about 100 °C. It is used for chemical tanks, plating barrels, fittings, pump parts, hinges and fabricated ducts.
What it is
PP resists most acids, alkalis and solvents, doesn't absorb water, and has good fatigue resistance (living hinges). Homopolymer is stiffer; copolymer is tougher at low temperature.
PP sheets weld well, making it a standard material for fabricated chemical tanks, fume ducts and plating equipment.
Typical applications
- Chemical and plating tanks
- Fume extraction ducts
- Pump and valve components
- Laboratory equipment
- Fittings and fabricated parts
Materials & grades
- PP homopolymer (PP-H)
- PP copolymer (PP-C)
- Glass-filled PP
- Flame-retardant PP
Points to consider
- Becomes brittle near and below 0 °C (use copolymer for cold).
- Weldable for tanks and ducts.
- Not resistant to strong oxidising acids and some solvents.
- Use UV-stabilised grades outdoors.
Frequently asked questions
Why is PP used for chemical tanks?
It resists most acids and alkalis, handles temperatures up to about 100 °C and welds easily into tanks.
What is the difference between PP-H and PP-C?
Homopolymer (PP-H) is stiffer and more heat resistant; copolymer (PP-C) is tougher at low temperatures.
Is polypropylene food safe?
Yes, food-grade PP is common in food containers and processing equipment.