Polypropylene (PP)

PP + GF20 (20 % Glass Fiber)

Low density, good flowability, light and economical. Stiffened by talc/glass fiber; copolymers have good impact strength.

These values are for plastic injection molding (not valid for extrusion, blow molding, etc.) and are typical for a general grade; for a specific brand/grade see the supplier data sheet.

Processing temperatures

Melt (injection) temperature	253 °C
Mold surface temperature	58 °C
Ejection temperature	118 °C

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

Physical properties (typical)

Density	1.05 g/cm³
Shrinkage (flow / cross)	0.4 / 1.1 %
Specific heat	1.58 kJ/kg·K
Thermal conductivity	0.25 W/m·K
Latent heat of crystallization (approx.)	99 kJ/kg

Drying

Usually no drying is required (check if it is moist).

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

Points to watch

Warpage and shrinkage differences (especially in filled grades)
Effect of mold temperature in hinge applications
UV/heat stability requires additives

Typical use: Automotive, packaging, household goods, closures, living hinges

Defects common with this material

Warpage

The part distorts or bends after it leaves the mold.

warpage · distortion · bowing

Sink mark

A dent on the surface opposite a thick section; the surface is drawn inwards.

sink mark · depression · sink

Dimensional variation and shrinkage differences

Part dimensions fall outside the tolerance or vary from cycle to cycle.

dimensional error · shrinkage · out of tolerance

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

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

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