Method and system for preparing densified lignocellulosic pulp for use in thermoplastic composite manufacturing processes

Abstract

A method of preparing lignocellulosic fibre aggregates from a densified mass of lignocellulosic fibre, such as densified bales, for use in manufacturing high performance, recyclable and moldable lignocellulosic fibre and thermoplastic composites, or articles made of the high performance, recyclable and moldable lignocellulosic fibre and thermoplastic composites is provided. The method includes: (a) feeding densified forms of lignocellulosic fibre into a size reduction device; and size reducing the lignocellulosic fibres so as to produce dense lignocellulosic fibre aggregates having an average size profile suitable for use in manufacturing high performance, recyclable and moldable lignocellulosic fibre and thermoplastic composites, or articles made of the high performance, recyclable and moldable lignocellulosic fibre and thermoplastic composites. The density of the lignocellulosic fibre is generally maintained throughout the method. A system for preparing lignocellulosic fibre in accordance with the method is also provided.

What is claimed is: 
     
         1 . A system for preparing dense lignocellulosic fibre aggregates for use in manufacturing high performance, recyclable and moldable lignocellulosic fibre and thermoplastic composites, or articles made of the high performance, recyclable and moldable lignocellulosic fibre and thermoplastic composites, characterized in that the system comprises:
 a) a size reduction apparatus operable to size reduce a densified mass of lignocellulosic fibre so as to produce dense lignocellulosic fibre aggregates having for use in manufacturing high performance, recyclable and moldable lignocellulosic fibre and thermoplastic composites, or articles made of the high performance, recyclable and moldable lignocellulosic fibre and thermoplastic composites, wherein the dense lignocellulosic fibre aggregates have individual panicle densities equal or virtually equal to the densified mass of lignocellulosic fibres density prior to being fed into the size reduction device.   
     
     
         2 . The system of  claim 1  characterized in that the size reduction apparatus is operable to produce the dense lignocellulosic fibre aggregates having an individual aggregate density approximately equal to the density of the densified mass of lignocellulosic fibre. 
     
     
         3 . The system of  claim 2  characterized in that the size reduction apparatus includes ax least one rotor. 
     
     
         4 . The system of  claim 3  characterized in that the rotor is operable at low RPM and at high torque, whereby the densified mass of lignocellulosic fibre is size reduced through contact with the rotor. 
     
     
         5 . The system of  claim 1  characterized in that the size reduction apparatus is operable at low RPM and with high torque. 
     
     
         6 . The system of  claim 1  characterized in that the size reduction apparatus is a low-speed high torque shredder equipped with at least one rotor. 
     
     
         7 . The system of  claim 6  characterized in that the least one rotor is operable to rotate at speeds between about 1 and 100 RPM. 
     
     
         8 . The system of  claim 1  characterized in that the size reduction apparatus is operable to produce the dense lignocellulosic fibre aggregates having a generally predetermined size. 
     
     
         9 . The system of  claim 1  characterized in that the size reduction apparatus is operable to produce the dense lignocellulosic fibre aggregates having a narrow aggregate size distribution with minimal degradation in fibre length. 
     
     
         10 . The system of  claim 1  characterized in that the size reduction apparatus is operable to produce the dense lignocellulosic fibre aggregates having reduced bridging for feeding into a manufacturing process resulting in manufacture of high performance, recyclable and moldable lignocellulosic fibre and thermoplastic composites, or articles made of the high performance, recyclable and moldable lignocellulosic fibre and thermoplastic composites. 
     
     
         11 . The system of  claim 1  characterized in that the size reduction apparatus is operably linked to one or more apparatuses for use in manufacturing lignocellulosic fibre and thermoplastic composites or products comprising lignocellulosic fibre and thermoplastic composites being operable to perform one or more of the following:
 a) extrusion; 
 b) compounding: 
 c) batch mixing; 
 d) injection-molding; and 
 e) in-line compounding and injection-molding apparatus 
 whereby the dense lignocellulosic fibre aggregates are fed at a predetermined mass How rate into the said one or more apparatuses. 
 
     
     
         12 . The system of  claim 11  characterized in that the one or more apparatuses include at least one rotating screw, whereby the dense fibre aggregates may be fed at the predetermined mass flow rate into the said one or more apparatuses. 
     
     
         13 . The system of  claim 12  characterized in that the one or more apparatuses include a a loss-in-weight screw feeder, whereby the dense fibre aggregates may be fed at the predetermined mass flow rate into the said one or more apparatuses. 
     
     
         14 . The system of  claim 13  characterized in that the loss-in-weight screw feeder has at least one spiral screw. 
     
     
         15 . The system of  claim 13  characterized in that the loss-in-weight screw feeder includes or is linked to an agitation mechanism. 
     
     
         16 . The system of  claim 1  characterized in that the size reduction apparatus includes a low-speed high-torque shredder equipped with one or more rotors and a screen. 
     
     
         17 . The system of  claim 1  characterized in that the size reduction apparatus is operable to produce the dense lignocellulosic fibre aggregates having an approximate bulk density of between 0.1 and 1.5 g/cm 3 . 
     
     
         18 . The system of  claim 1  characterized in that the size reduction apparatus is operable to produce the dense lignocellulosic fibre aggregates having an average width of between 0.2 and 3 inches. 
     
     
         19 . The method as claimed in  claim 1  characterized in that the densified mass of lignocellulosic fibre is in densified bale form. 
     
     
         20 . The system as claimed in  claim 1  characterized in that the densified mass of lignocellulosic fibre is in densified bale form.