PVC

PVC-U (Rigid PVC)

Rigid (PVC-U) or flexible (PVC-P). Very heat-sensitive; if it degrades, HCl is released and corrodes the mold.

Processing temperatures

Melt (injection) temperature185 °C
Mold surface temperature40 °C
Ejection temperature70 °C

Typical values. They vary (±) with grade and manufacturer; see the data sheet.

Physical properties (typical)

Density1.4 g/cm³
Shrinkage (flow / cross)0.4 / 0.4 %
Specific heat1 kJ/kg·K
Thermal conductivity0.15 W/m·K

Drying

Usually not required.

For exact conditions see the material data sheet. Drying guide →

Points to watch

  • Residence time and temperature must be kept short/low
  • Mold and screw require corrosion resistance (stainless/coated)
  • A cold runner may be preferred

Typical use: Pipe fittings, cable sheathing, profile parts

Defects common with this material

Stress cracking

The part cracks during assembly, on contact with oil/solvent or over time; the crack usually starts at stressed areas.

stress crack · crack · environmental stress cracking

Weld line (knit line)

A line and a weak zone where two melt fronts meet.

weld line · knit line · joining line

Short shot (incomplete fill)

The cavity does not fill completely; the farthest or thinnest area of the part stays incomplete.

incomplete fill · underfill · non-fill

Flash

Plastic escapes through the parting line or around the ejector pins.

flash · overflow · parting line flash

Other grades in the same family

PVC-P (Flexible PVC)

Amorphous, halogenated175 °C melt · 25 °C mold

Do the values for this material not match your grade? and we will correct them.