Structural biocomposite materials, systems, and methods

Abstract

A structural biocomposite material that incorporates small strands of agricultural straw, typically non-wood cellulosic straws, such as cereal grain straw.

What is claimed is:  
     
         1 . A structural biocomposite panel comprising flat non-wood cellulosic strands and a resin, wherein at least about 40 wt-% of the panel comprises flat non-wood cellulosic strands having a length of about 0.25 inch (6.35 mm) to no greater than about 2 inches (50 mm) and a particle size distribution of about 4 mesh (5.46 mm) to about 12 mesh (1.52 mm).  
     
     
         2 . The structural biocomposite panel of  claim 1  wherein the flat non-wood cellulosic strands having a length of about 0.25 inch (6.35 mm) to no greater than about 2 inches (50 mm) form surface regions of the panel.  
     
     
         3 . The structural biocomposite panel of  claim 2  comprising a core comprising non-wood cellulosic strands having a different particle size than the non-wood cellulosic strands at the surfaces.  
     
     
         4 . The structural biocomposite panel of  claim 1  comprising a homogenous construction.  
     
     
         5 . The structural biocomposite panel of  claim 1  comprising a two-layer construction.  
     
     
         6 . The structural biocomposite panel of  claim 1  comprising a three-layer construction  
     
     
         7 . The structural biocomposite panel of  claim 6  wherein the flat non-wood cellulosic strands having a length of about 0.25 inch (6.35 mm) to no greater than about 2 inches (50 mm) form surface regions of the panel.  
     
     
         8 . The structural biocomposite panel of  claim 1  wherein the non-wood cellulosic strands comprise strands of cereal grain straw.  
     
     
         9 . The structural biocomposite panel of  claim 8  wherein the cereal grain straw is selected from the group consisting of wheat, oat, rice, barley, millet, rye, and combinations thereof.  
     
     
         10 . The structural biocomposite panel of  claim 9  wherein the cereal grain straw is wheat.  
     
     
         11 . The structural biocomposite panel of  claim 1  wherein the non-wood cellulosic strands have a width of about 0.005 inch (0.127 mm) to about 0.1 inch (2.54 mm).  
     
     
         12 . The structural biocomposite panel of  claim 1  wherein the non-wood cellulosic strands have an average ratio of length:width:thickness of about 100:10:1.  
     
     
         13 . The structural biocomposite panel of  claim 1  wherein at least about 50 wt-% of the panel comprises flat non-wood cellulosic strands having a length of about 0.25 inch (6.35 mm) to no greater than about 2 inches (50 mm) and a particle size distribution of about 4 mesh (5.46 mm) to about 12 mesh (1.52 mm).  
     
     
         14 . The structural biocomposite panel of  claim 13  wherein the non-wood cellulosic strands have a particle size distribution of about 4 mesh (5.46 mm) to about 10 mesh (1.905 mm).  
     
     
         15 . The structural biocomposite panel of  claim 1  wherein the resin comprises an isocyanate resin.  
     
     
         16 . The structural biocomposite panel of  claim 1  wherein the resin comprises an acid-catalyzed resin.  
     
     
         17 . The structural biocomposite panel of  claim 1  which is sanded.  
     
     
         18 . The structural biocomposite panel of  claim 17  further comprising a laminate comprising metal, melamine foil, high pressure laminate, or a medium or high density overlay.  
     
     
         19 . A structural biocomposite panel comprising flat non-wood cellulosic strands and a resin, wherein at least about 40 wt-% of the panel comprises flat non-wood cellulosic strands having a length of about 0.25 inch (6.35 mm) to no greater than about 2 inches (50 mm) and a particle size distribution of about 4 mesh (5.46 mm) to about 12 mesh (1.52 mm), and further wherein the panel comprises surface regions comprising the flat non-wood cellulosic strands having a length of about 0.25 inch (6.35 mm) to no greater than about 2 inches (50 mm) and a core comprising non-wood cellulosic strands having a smaller particle size than the non-wood cellulosic strands at the surfaces.  
     
     
         20 . The structural biocomposite panel of  claim 19  wherein the non-wood cellulosic strands have an average ratio of length:width:thickness of about 100:10:1.  
     
     
         21 . A structural biocomposite panel comprising flat non-wood cellulosic strands and a resin, wherein the panel comprises surface regions comprising non-wood cellulosic strands and a core comprising non-wood cellulosic strands having a smaller particle size than the non-wood cellulosic strands at the surfaces.  
     
     
         22 . A structural biocomposite panel comprising flat non-wood cellulosic strands and a resin, wherein at least about 40 wt-% of the panel comprises flat non-wood cellulosic strands having a length of about 0.25 inch (6.35 mm) to no greater than about 2 inches (50 mm), a width of about 0.005 inch (0.127 mm) to about 0.1 inch (2.54 mm), an average ratio of length:width:thickness of about 100:10: 1, and a particle size distribution of about 2 mesh (6.35 mm) to about 12 mesh (1.52 mm).  
     
     
         23 . A sample of flat non-wood cellulosic strands comprising at least about 75 wt-% of the strands have a length of about 0.25 inch (6.35 mm) to no greater than about 2 inches (50 mm), a width of about 0.005 inch (0.127 mm) to about 0.1 inch (2.54 mm), an average ratio of length:width:thickness of about 100:10: 1, and a particle size distribution of about 4 mesh (5.46 mm) to about 12 mesh (1.52 mm).  
     
     
         24 . A method of preparing flat non-wood cellulosic strands, the method comprising: 
 providing non-wood cellulosic straw;    impact milling the non-wood cellulosic straw into strands; and    classifying the strands to form a sample of flat non-wood cellulosic strands comprising at least about 75 wt-% of the strands having a length of about 0.25 inch (6.35 mm) to no greater than about 2 inches (50 mm).    
     
     
         25 . The method of  claim 24  wherein impact milling and classifying are repeated.  
     
     
         26 . The method of  claim 24  wherein providing non-wood cellulosic straw comprises providing a bale of non-wood cellulosic straw and reducing the bale.  
     
     
         27 . The method of  claim 26  wherein reducing the bale comprises rotary slicing.  
     
     
         28 . The method of  claim 27  wherein reducing the bale comprises rotary slicing and classifying.  
     
     
         29 . The method of  claim 24  wherein classifying after impact milling comprises air density classifying, rotary screening, or a combination thereof.  
     
     
         30 . The method of  claim 24  wherein the sample of flat non-wood cellulosic strands comprises at least about 75 wt-% of the strands having a width of about 0.005 inch (0.127 mm) to about 0.1 inch (2.54 mm).  
     
     
         31 . The method of  claim 24  wherein the sample of flat non-wood cellulosic strands comprises at least about 75 wt-% of the strands having an average ratio of length:width:thickness of about 100:10:1.  
     
     
         32 . The method of  claim 24  wherein the sample of flat non-wood cellulosic strands comprises at least about 75 wt-% of the strands having a particle size distribution of about 4 mesh (5.46 mm) to about 12 mesh (1.52 mm).  
     
     
         33 . The method of  claim 24  wherein the non-wood cellulosic strands comprise strands of cereal grain straw.  
     
     
         34 . The method of  claim 33  wherein the cereal grain straw is selected from the group consisting of wheat, oat, rice, barley, millet, rye, and combinations thereof.  
     
     
         35 . The method of  claim 34  wherein the cereal grain straw is wheat.  
     
     
         36 . The method of  claim 24  further comprising drying the strands.  
     
     
         37 . The method of  claim 36  further comprising classifying the dried strands.  
     
     
         38 . A method of preparing a structural biocomposite panel, the method comprising: 
 providing non-wood cellulosic strands coated with a resin;    forming a matt having larger strands on the surfaces of the matt and smaller strands toward the core; and    compressing the matt to form a structural biocomposite panel.    
     
     
         39 . The method of  claim 38  wherein the matt is formed using a reversed windformer to place larger strands on the surfaces of the matt and smaller strands toward the core.  
     
     
         40 . The method of  claim 39  wherein the reversed windformer includes an orienting device for orienting the strands closer to the surface.  
     
     
         41 . The method of  claim 38  the matt is formed using a reversed gradient screen former to place larger strands on the surfaces of the matt and smaller strands toward the core.  
     
     
         42 . The method of  claim 41  wherein the reversed gradient screen former includes an orienting device for orienting the strands closer to the surface.  
     
     
         43 . The method of  claim 38  wherein the matt comprises at least two layers.  
     
     
         44 . The method of  claim 38  further comprising applying soap, wax, or oil to the matt prior to compressing.  
     
     
         45 . The method of  claim 38  wherein the matt is compressed on a screen.  
     
     
         46 . A method of preparing a structural biocomposite panel, the method comprising: 
 providing non-wood cellulosic strands coated with a resin;    forming a matt having a substantially uniform distribution of strands; wherein at least about 75 wt-% of the strands have a length of about 0.25 inch (6.35 mm) to no greater than about 2 inches (50 mm), a width of about 0.005 inch (0.127 mm) to about 0.1 inch (2.54 mm), an average ratio of length:width:thickness of about 100:10:1, and a particle size distribution of about 4 mesh (5.46 mm) to about 12 mesh (1.52 mm); and    compressing the matt to form a structural biocomposite panel.    
     
     
         47 . The method of  claim 46  further comprising applying soap, wax, or oil to the matt prior to compressing.  
     
     
         48 . The method of  claim 46  wherein the matt is compressed on a screen.  
     
     
         49 . A method of preparing a structural biocomposite panel, the method comprising: 
 providing non-wood cellulosic straw;    impact milling the non-wood cellulosic straw into strands;    classifying the strands to form a sample of flat non-wood cellulosic strands comprising at least about 75 wt-% of the strands having a length of about 0.25 inch (6.35 mm) to no greater than about 2 inches (50 mm);    coating the strands with a resin;    forming a matt comprising the resin-coated strands; and    compressing the matt to form a structural biocomposite panel.    
     
     
         50 . The method of  claim 49  wherein forming a matt comprises forming a matt having larger strands on the surfaces of the matt and smaller strands toward the core.  
     
     
         51 . The method of  claim 50  wherein the matt is formed using a reversed windformer to place larger strands on the surfaces of the matt and smaller strands toward the core.  
     
     
         52 . The method of  claim 51  wherein the reversed windformer includes an orienting device for orienting the strands closer to the surface.  
     
     
         53 . The method of  claim 50  the matt is formed using a reversed gradient screen former to place larger strands on the surfaces of the matt and smaller strands toward the core.  
     
     
         54 . The method of  claim 53  wherein the reversed gradient screen former includes an orienting device for orienting the strands closer to the surface.  
     
     
         55 . The method of  claim 50  wherein the matt has a substantially uniform distribution of strands.  
     
     
         56 . The method of  claim 50  further comprising applying soap, wax, or oil to the matt prior to compressing.  
     
     
         57 . The method of  claim 50  wherein the matt is compressed on a screen.  
     
     
         58 . The flat non-wood cellulosic strands preparable by the method of  claim 24 .  
     
     
         59 . The panel preparable by the method of  claim 38 .  
     
     
         60 . The panel preparable by the method of claim  46 .