Degassing.

Reasons for degassing.

• Operate at an economic throughput,

• Keep max. melt temperature as low as possible (degradation, color),

• Minimize the residuals,

• Achieve good optical and mechanical properties,

• Avoid gels and “black spots”.

Degassing processes.

General layout of degassing processes.

Principle of degassing.

Principle of degassing.

Standard vent ports.

Limitations for degassing

Degassing.

Guide lines for

Guide lines for polymer degassing.

• The polymer has to be completely molten.

• The fillers and reinforcing material have to be wetted completely with melt.

• The melt temperature has to be as high as possible.

• The degassing zone has to be as long as possible.

• The vacuum has to be below the partial pressure of the material to be degassed.

• The fill factor should be below 40% .

• The vent port has to be chosen according the polymer characteristics