Method for purging thermoplastic extruders

摘要

Methods and additives for purging thermoplastic extruders and associated apparatus are included which involve the addition of a purging additive to a follower thermoplastic resin which additive when heated causes the follower resin to froth as it passes through the unit, the passage of frothed resin thereby causing the removal of the contents of the unit, which contents includes resident resin along with resident additives, degraded materials and any other undesired materials which may be present in the unit.