A thermoplastic material extrusion mechanism is provided which includes a die head having a centrally disposed high velocity gas delivery means adapted to continuously emit a jet of a gas having shear layers, at least one chamber for the thermoplastic material, thermoplastic material delivery means arranged...http://www.google.de/patents/US4818464?utm_source=gb-gplus-sharePatent US4818464 - Extrusion process using a central air jet
