4. Extrusion

4.1 Extruder

The sheet-plate sector is undoubtedly a strong market for single-screw extruders.

Barring exceptional circumstances, there are no bivis, as the market does not lend itself to them:

• In general, the raw materials used are simple mixtures (in the qualitative sense) or pre-compounded granules (alloys or blends);

• PVC sheets are obtained by calendering.

These markets are too competitive to bear the extra investment and operating costs involved in using a bivis.