Engineering plastics
PVDF
Polyvinylidene fluoride
A mechanically strong fluoropolymer with high chemical resistance. The step up from PVC and PP for thermoplastic valve bodies and trim in acid, chlorine and brine lines.
- HARDNESS
- Rockwell R100
- Rm · MPa (typical)
- 52–54
- TEMPERATURE
- −20 … +140 °C
- COST
Design
Polymer; defined by its structure and filler type rather than chemical composition.
Mechanical properties
| TYPE · CONDITION | Rm MPa | Elongation at break % | Hardness | Coefficient of friction | Water absorption % |
|---|---|---|---|---|---|
| Unfilled, typical | 52–54 | 20–50 | Rockwell R100 | 0.2–0.4 | 0.02–1.0 |
Typical values (the standard gives no minimum values); they vary with grade and filler. Converted from US units.
Service temperature
−20 °C+140 °C−200−1000100200300400500600700800
−20 … 140 °C. The allowable pressure drops above 20 °C.
Physical properties and heat treatment
- DENSITY
- ≈ 1.77 g/cm³
Media suitability GENERAL TREND
Water
Steam
Mineral oil
Fuel, aliphatic HC
Ozone, outdoor
Dilute acid
Caustic
Ketones, esters
Emsal assessment. The final choice is made from corrosion tables, taking concentration, temperature, chloride content and flow velocity into account.
Strengths and weaknesses
Strengths
- Very good resistance to acids and halogens
- Resistant to UV and outdoor exposure
- Higher strength than PTFE, weldable
Weaknesses
- Weak in strong bases and amines
- Swelling in ketones
- More expensive than PVC and PP
Manufacturing and use
- ECONOMY
- High.
- MANUFACTURING METHODS
- Injection moulding · Extrusion · Turning from bar
- TYPICAL VALVE PARTS
- Body (thermoplastic valve) · Ball · Diaphragm · Lining
Source: ISO 10931 (system). Values compiled and verified by Emsal Vana; for binding values, refer to the current edition of the standard and the material certificate.