Method and apparatus for the production of high tenacity polyolefin sheet

9) A process for the production of a coherent virtually full density polyolefin sheet suitable for further processing by drawing to produce a high tenacity, highly oriented film, tape, fiber or sheet from a polyolefin powder comprising:

• a) feeding a metered amount of polyolefin powder into the nip between two counter rotating heated calendar rolls initially set at a gap smaller than the size of the smallest polyolefin powder particle and at a temperature above the melting point of the polyolefin powder;
• b) rolling the powder through the nip under these conditions until a coherent polyolefin sheet is produced;
• and
• c) once a coherent sheet of polyolefin exits the nip lowering the temperature in the nip to a temperature below the melting point of the polyolefin powder and increasing the gap to a desired level above the thickness of the largest powder particle.

15) A process for the production of high tenacity, highly oriented polyolefin sheet comprising:

• a) feeding a metered amount of polyolefin powder into the nip between two counter rotating heated calendar rolls set at a temperature below the melting point of the polyolefin powder;
• b) rolling the powder through the nip to produce a coherent sheet of polyolefin;
• and
• c) drawing the coherent sheet under controlled tension at a temperature of between about 140 and 158° C. to produce a high tenacity, highly oriented polyolefin sheet having a high heat of fusion.

17) Apparatus for the production of a coherent virtually full density polyolefin sheet suitable for further processing by drawing to produce a high tenacity, highly oriented film, tape, fiber or sheet from a polyolefin powder comprising:

• a) a hopper including a metering mechanism;
• b) a vibratory chute;
• c) a containment plate;
• d) a pair of counter rotating heated calendar rolls defining a nip there between;
• and
• e) a heater above the vibratory chute;
• wherein powder is delivered from the hopper to the vibratory chute via the metering mechanism where the powder is preheated by the heater and thence to the containment plate where it accumulates and is introduced into the nip.