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PP (Polypropylene)

Also Known As

  • Celstran
  • Hostalen PP
  • Lacqtene P
  • Novolen
  • Propathene
  • Stamylan P
  • Vestolen P

Typical Machine Settings: Subject To Polymer Grade

Nozzle

Front

Centre

Rear

Barrel Temperature

215 - 260oC

215 - 245oC

205 - 225oC

195 - 215oC

Melt Temperature

215 - 260oC

Must be measured with a pyrometer by taking an airshot through the injection machine nozzle.

Hot Runner Temperature

215 - 260oC

Mould Temperature

15 - 65oC

Run at upper end of range for best surface finish.

Injection Rate

Fast

Specific Injection Pressure

700 - 1400 Bar (10,000 - 20,000psi)

Screw Back Pressure

3.5 - 14.0 Bar (100 - 200psi)

Screw Speed

Fast

Processing Features

Structure

Semi-Crystalline

Specific Gravity

0.90

Viscosity

Usually Low

Can use small runners.

Shear Rate Susceptibility

Low

Temperature Window

Wide

Residence Time

Long

Start-Up Precedure
  • Ensure all heaters are thoroughly baked dry - do not rely on brief ‘soft start’ systems to do this.
  • Fast Heat controllers automatically and safely bakeout wet heaters - ask for details.
  • Turn on water lines to stabilise tool and manifold temperatures.
  • Turn on manifold control zone(s) and allow to warm up until measured value is within 10oC of setpoint.
  • Now turn on tip zones and allow to settle at setpoint for 5 - 10 minutes before starting production.
  • Take an airshot from the machine barrel and check that the melt temperature is correct.
  • Start moulding parts on a semi-automatic cycle until suitable machine settings are established.
  • Avoid lengthy delays between cycles during this setting procedure.
  • Switch to automatic cycle when parts are being produced, and fine tune the machine settings

Shut-Down Precedure

The machine and mould may be shut down normally, without purging the Polypropylene from either the barrel or the hot runner.