Plastic processing apparatus and related methods

Abstract

Provided is a method of processing a plastic, the method comprising introducing a plastic slurry having particles with a particle size of less than 20 mm into a macerator, the macerator comprising an inlet configured to receive a flow of plastic slurry, an outlet, three or more concentric bodies that rotate relative to each other, each body comprising a plurality of apertures to define a flow path through each body, wherein the plastic slurry traverses the flow path from the inlet to the outlet via the at least one aperture of each body to produce an outlet plastic slurry. Also provided are systems for processing plastic, comprising the macerator. Also provided are methods of manufacturing a composite wood product that comprises plastic particles.

We claim: 
     
         1 . A method of processing plastic, comprising:
 a) introducing a plastic slurry having particles with a particle size of less than 20 mm into a macerator, the macerator comprising:
 a housing that defines a chamber, an inlet, and an outlet, the inlet configured to receive a flow of slurry, 
 three or more concentric bodies that rotate relative to each other within the housing, each concentric body comprising a plurality of apertures to define a flow path through each concentric body, and 
 a motor to drive the rotating of the concentric body or bodies; and 
   b) operating the motor to drive one or more of the concentric bodies, and   wherein the slurry traverses the flow path from the inlet to the outlet via the at least one aperture of each concentric body to produce an outlet slurry comprising particles having a particle size less than the particles of the plastic slurry introduced into the inlet of the chamber.   
     
     
         2 . The method of  claim 1 , wherein the outlet slurry comprises particles having a mean particle size of less than 20 μm. 
     
     
         3 . The method of  claim 1 , wherein the concentric bodies have a horizontal axis of rotation, and the inlet is at the base of the chamber and the outlet is at the top of the chamber, such that the slurry traverses the apertures of the concentric bodies vertically to flow from the inlet to the outlet. 
     
     
         4 . The method of  claim 1 , wherein the plastic slurry comprises about 10 to about 50% by weight of solid material. 
     
     
         5 . The method of  claim 1 , wherein the concentric bodies rotate relative to each other at a rotational speed of about 100 to about 1,000 RPM. 
     
     
         6 . The method of  claim 1 , wherein a ratio of liquid to solid material in the plastic slurry is about 1 liter of liquid to about 0.5 to about 1.5 kg of plastic. 
     
     
         7 . The method of  claim 1 , wherein a flow rate of the plastic slurry through the macerator is about 10 to about 1,000 liters per minute. 
     
     
         8 . A system for processing plastic, comprising:
 a vessel that comprises an agitator, the vessel receiving plastic having a particle size of less than 20 mm and a liquid to form a plastic slurry;   a macerator into which the plastic slurry from the vessel is introduced, the macerator comprising:
 a housing that defines a chamber, an inlet, and an outlet, the inlet configured to receive a flow of the plastic slurry, 
 three or more concentric bodies that rotate relative to each other within the housing, each concentric body comprising a plurality of apertures to define a flow path through each concentric body, and 
 a motor to drive the rotating concentric body or bodies; and 
 a motor to drive rotation of one or more of the concentric body or bodies, and 
   wherein the plastic slurry traverses the flow path from the inlet to the outlet via the at least one aperture of each concentric body to produce an outlet slurry comprising particles having a particle size less than the particles of the plastic slurry introduced into the inlet.   
     
     
         9 . The system of  claim 8 , wherein the agitator maintains the plastic particles suspended in the vessel and creates a substantially homogeneous mix of plastic particles in the vessel. 
     
     
         10 . The system of  claim 8 , wherein the agitator comprises a stirrer having a blade to reduce the diameter of the plastic particles to less than about 11 mm. 
     
     
         11 . The system of  claim 8 , wherein the vessel comprises one or more baffles that extend from an inner wall of the vessel. 
     
     
         12 . A method of manufacturing a composite wood product that comprises plastic particles, the method comprising
 mixing a wood fiber, a powdered plastic, and a cross linker in a press; and   subjecting the mixture in the press to a force of between 100 and 200 tonnes at a temperature of about 180° C. to 200° C.   
     
     
         13 . The method of  claim 12 , wherein the composite wood product is selected from among a composite board, plywood, laminated veneer lumber, and a reconstituted wood product that is a particle board or oriented strand board. 
     
     
         14 . The method of  claim 12 , wherein the wood fiber comprises wood chip. 
     
     
         15 . The method of  claim 12 , wherein the wood fiber is between 10 mm and 100 mm long. 
     
     
         16 . The method of  claim 12 , further comprising mixing saw dust with the wood fiber, the powdered plastic, and the cross linker. 
     
     
         17 . The method of  claim 12 , wherein the powdered plastic comprises a polyethylene powder. 
     
     
         18 . The method of  claim 12 , wherein the powdered plastic comprises a high density polyethylene powder. 
     
     
         19 . The method of  claim 12 , wherein the cross linker is an organic peroxide. 
     
     
         20 . The method of  claim 12 , wherein the organic peroxide is a Luperox® organic peroxide cross linker.