Polyamide drying and conditioning.
In the area of PA, Buhler has been building drying and SSP plants since 1982, and in this time has built some 90 lines worldwide. Buhler supplies specialized equipment for the thermal handling of PA pellets without mechanical agitation. This includes process design through the building of turnkey plants as well as retrofitting existing plants.Buhler has extensive experience with the thermal treatment of a wide range of polyamide types: from PA4,6 through to PA11 and 12, and in particular PA6,6 and PA6.
PA pellets must be dried before melting and final processing in order to prevent molecular weight fluctuations. If too much water is present during melting, the polycondensation reaction can be reversed, resulting in a loss in molecular weight. However if the material is over-dried, an equally undesirable increase in molecular weight can occur. For this reason, the drying of PA is often referred to as conditioning, whereby the material is dried to the equilibrium moisture content – that is to say an even moisture content profile throughout the pellets.
