Extruder screw and method for extruding liquid crystalline polymers

An extruder screw for a low melt viscosity polymer which forms an anisotropic melt phase, comprising:

• a feed section;
• a barrier section for uniformly melting the polymer along a substantial portion of the length of the screw;
• a compression section for compressing the melted polymer over a comparatively small compression ratio;
• a metering section;
• a filter downstream of the metering section;
• said compression section being arranged to produce pressure sufficiently high to force said material through the filter, said compression section having channels sufficiently deep to permit a high volume flow rate;
• and
• means for rotating said screw at a high velocity to ensure the high volume flow rate through said channels of said compression section.

An extruder screw for a low melt viscosity polymer which forms an anisotropic melt phase, comprising:

• a feed section having constant depth channels;
• a barrier section for uniformly melting the polymer along a substantial portion of the length of the screw in said barrier section including a melt channel and a solids channel in a double helix arrangement, the solids channel gradually decreasing in depth and the melt channel having a constant depth;
• a compression section having a channel with a gradually decreasing channel depth for compressing the melted polymer over a comparatively small compression ratio;
• a transition section for connecting the barrier section with the compression section;
• a metering section having a channel with a constant channel depth equal to the smallest depth of the channel in the compression section;
• and
• an external diameter of the screw being constant throughout the length of the screw.