Apparatus and method for preparing a plasticated material

Apparatus for preparing a plasticated material from solids of a given material introduced into the apparatus, said apparatus comprising:

• a barrel having an inner surface;
• supply means for introducing said solids of a given material into the barrel;
• a screw conveyor in the barrel, said screw conveyor including a flight which, together with the inner surface of the barrel, defines a channel for conveying the given material from the supply means in a downstream direction as the material is melted within the channel, said flight having a leading face facing downstream and a trailing face facing upstream, said channel having a predetermined width between confronting leading and trailing faces;
• the channel including a solids conveying zone having a length extending between the supply means and a point where the temperature of the inner surface of the barrel is at the melting point of the given material, and a melting zone located downstream from the solids conveying zone;
• and
• means on the screw conveyor, at the leading face of the flight, in the vicinity of said point where the temperature of the inner surface of the barrel is at the melting point of the given material for inducing the formation of a melt pool in the channel at a location downstream from the supply means a distance approximately equal to the length of the solids conveying zone, said melt pool inducing means having a configuration which effects a change in the width of the channel in at least that portion of the channel located in the vicinity of said point, said change in width being accompanied by so abrupt an increase in width at that portion as to form a void between the solids and the leading face of the flight to accommodate the melt pool at said location.