Biodegradable or compostable containers

Abstract

The present invention provides an improved method and materials for forming biodegradable containers that can hold food products in dry, damp or wet conditions and provides the biodegradable containers prepared according to the disclosed process. The containers are produced through the use of a pre-gelled starch suspension that is unique in its ability to form hydrated gels and to maintain this gel structure in the presence of many other types of materials and at low temperatures.

1 . A process for forming a biodegradable material by: 
 (a) forming a pre-gelled starch suspension that is maintained between approximately 0 and 60° C.;    (b) adding to the pre-gelled starch suspension a dry or damp, homogeneous mixture containing at least wood fibers having an aspect ratio between approximately 1:2 and 1:8 (width:length) to form a homogenous moldable composition; and    (c) molding the homogenous moldable composition with heat to form a biodegradable material.    
   
   
       2 . A process for forming a biodegradable material by: 
 (a) forming a first pre-gelled starch suspension that is maintained at a low temperature;    (b) mixing together wood fibers or flour (having an aspect ratio between approximately 1:2 and 1:8), a second pre-gelled starch suspension, and/or a native starch to form a homogenous mixture;    (c) adding to the pre-gelled starch suspension the dry or damp, homogeneous mixture to form a homogenous moldable composition; and    (d) molding the homogenous moldable composition with heat to form a biodegradable material.    
   
   
       3 . A process for forming a biodegradable material by: 
 (a) forming a pre-gelled starch suspension (the pre-gel) produced from approximately 3-10% potato starch by weight of the pre-gel and approximately 90-97% water by weight of the pre-gel such that the pre-gelled suspension is maintained at low temperature;    (b) mixing together wood fibers or flour (having an aspect ratio between approximately 1:2 and 1:8), a pre-gelled starch suspension produced from approximately 15% corn starch (by weight of the pre-gel) and approximately 85% water by weight of the pre-gel, and a native starch (for example approximately 50-70%, or, more specifically, 57-65.8%, corn starch (by weight of the homogenous moldable composition) or approximately 2-15% or, more specifically, 3-5% potato starch (by weight of the homogenous moldable composition)) to form a homogeneous mixture;    (c) adding to the pre-gelled potato starch suspension the homogeneous mixture to form a final homogenous moldable composition; and    (d) molding the homogenous moldable composition with heat to form a biodegradable material.    
   
   
       4 . A process for forming a biodegradable material by: 
 (a) forming a pre-gelled paper starch suspension that is maintained at low temperatures;    (b) adding to the pre-gelled paper starch suspension a dry or damp, homogeneous mixture containing at least wood fibers having an aspect ratio between approximately 1:2 and 1:8 (width:length) to form a homogeneous moldable composition; and    (c) molding the homogeneous moldable composition with heat to form a biodegradable material.    
   
   
       5 . A process for forming a biodegradable material by: 
 (a) forming a first pre-gelled paper starch suspension that is maintained at low temperatures;    (b) mixing together wood fibers or flour (having an aspect ratio between approximately 1:2 and 1:8), and a native starch(s) to form a homogeneous mixture;    (c) adding to the first pre-gelled starch suspension the homogenous mixture to form a homogenous moldable composition; and    (d) molding the homogenous moldable composition with heat to form a biodegradable material.    
   
   
       6 . A process for forming a biodegradable material by: 
 (a) forming a pre-gelled starch suspension produced from approximately 2-15% potato starch (by weight of the pre-gel), preferably about 2.5, 5, 10, or 15%; approximately 5-10% paper pulp (by weight of the pre-gel), preferably about 5.9-8%; and approximately 75-95% water (by weight of the pre-gel) such that the pre-gelled suspension is maintained at low temperatures;    (b) mixing together wood fibers or flour (having an aspect ratio between approximately 1:2 and 1:8, preferably between 1:2 and 1:4), native corn starch and native potato starch to form a homogeneous mixture;    (c) adding to the pre-gelled potato starch suspension the homogeneous mixture to form a homogenous moldable composition; and    (d) molding the homogenous moldable composition with heat to form a biodegradable material.    
   
   
       7 . The process of claims  1 - 6 , further comprising adding a material selected from the following list to the wood fibers to form a homogeneous mixture: 
 (i) waxes, fatty alcohols, phospholipids or other high molecular weight biochemicals, such as glycerol;    (ii) approximately 0.5-20% water (by weight of the homogenous moldable composition);    (iii) baking powder; and/or    (iv) natural earth fillers, clays, bentonite, amorphous raw products, gypsum or calcium sulfate, minerals such as limestone, or man made inert fillers.    
   
   
       8 . A process comprising the steps of: 
 (a) forming a pre-gelled starch suspension or paper starch suspension that is maintained at a low temperature;    (b) mixing together wood fibers or flour (having an aspect ratio between approximately 1:2 and 1:8) and (i) dry or damp starch; (ii) pre-gelled starch; (iii) wax, fatty alcohol, phospholipid and/or other high molecular weight biochemicals; (v) baking powder; and/or (vi) homogenous moldable composition of natural earth fillers, clays, bentonite, amorphous raw products, gypsum or calcium sulfate, minerals such as limestone, and man made materials such as fly-ash to form a homogeneous mixture;    (c) adding to the pre-gelled starch suspension the dry or damp, homogeneous mixture to form a homogenous moldable composition; and    (d) molding the homogenous moldable composition with heat to form a biodegradable material.    
   
   
       9 . The process of claims  1 - 8 , wherein the pregelled starch suspension is produced from approximately 2.5-15% starch (by weight of the pre-gel), and from approximately 85-97.5% of water by weight of the homogenous moldable composition.  
   
   
       10 . The process of claims  1 - 8 , wherein the pre-gelled starch suspension I produced from approximately 2.5-5.5% starch and from approximately 94.5-97.5% water.  
   
   
       11 . The process of claims  1 - 8 , wherein the pre-gelled starch suspension is produced from approximately 2.5-10% potato starch, and 90 to 97.5% water (by weight of the pre-gel).  
   
   
       12 . The process of claims  1 - 8 , wherein the pre-gelled starch suspension is produced from approximately 15% corn starch (by weight of the pre-gel).  
   
   
       13 . The process of claims  1 - 8 , wherein the pregelled paper starch solution is produced from approximately 5-10% paper pulp (by weight of the pre-gel), approximately 5-15%, natural starch, and approximately 75-90% water (by weight of the pre-gel).  
   
   
       14 . The process of claims  1 - 8 , wherein the starch is corn starch or potato starch.  
   
   
       15 . The process of claims  1 - 8 , wherein the starch is a mixture of potato starch and corn starch.  
   
   
       16 . The process of claims  1 - 8 , wherein corn starch comprises approximately 4-18%, by weight of the homogenous moldable composition.  
   
   
       17 . The process of claims  1 - 8 , wherein wood fibers or flour comprise approximately 11-24% of the homogenous moldable composition that contains the pregelled starch solution.  
   
   
       18 . The process of claims  1 - 8 , wherein the wood fibers or flour comprise approximately 7-11% by weight of the homogenous moldable composition that contains the pregelled paper starch solution.  
   
   
       19 . The process of claims  1 - 8 , wherein the wood fibers or flour have an aspect ratio, width to length of between approximately 1:2 and 1:8.  
   
   
       20 . A biodegradable, compostable material made according to a process of claims  1 - 19  or claims  24 - 27 .  
   
   
       21 . The material of  claim 20  that disintegrates to component parts in less than one year.  
   
   
       22 . The material of  claim 20  that disintegrates to component molecules in less than six months.  
   
   
       23 . The material of  claim 20 , that disintegrates in 24 days.  
   
   
       24 . The process of claims  1 - 19  that further comprises using pressure in combination or alternation with heat to mold the biodegradable material.  
   
   
       25 . The process of  claim 24 , wherein the pressure is between approximately 2-3 psi  
   
   
       26 . The process of claims  1 - 19 , wherein heat is used to produce the material.  
   
   
       27 . The process of  claim 26 , wherein the heat used to mold the biodegradable materials is between approximately 150-250° C.  
   
   
       28 . The material of  claim 20  coated with a suitable liquid-resistant coating.  
   
   
       29 . The material the  claim 28 , wherein the coating is selected from coatings such as PROTECoat (from New Coat, Inc.), Zein® (a biodegradable material isolated from corn); polylactic acid; poly hydroxyalkanoate; bacterial cellulose; chitosan based polymer; or waxes and oil based coatings.  
   
   
       30 . The material of  claim 28 , wherein the coating is applied either as a thin film, sprayed or dipped.  
   
   
       31 . A process for creating a waterproof material by: 
 (a) forming a first pre-gelled starch suspension that is maintained at low temperatures;    (b) mixing together wood fibers or flour (having an aspect ratio between approximately 1:2 and 1:8), and wax, fatty alcohol, phospholipids or other high molecular weight biochemical, such as glycerol;    (c) adding to the first pre-gelled starch suspension the homogeneous mixture containing the wood fiber and other material;    (d) molding the homogeneous composition with heat to form a biodegradable material; and    (e) coating the material with a liquid-resistant coating.    
   
   
       32 . The material of  claim 31 , wherein the coating is includes but not limited to PROTECoat, Zein®; polylacticacid; poly hydroxyalkanoate; bacterial cellulose; chitosan based polymers; or waxes and oil based coatings.  
   
   
       33 . The process of  claim 28 , wherein a vacuum is used to form a film around the molded article.  
   
   
       34 . A process is provided for creating an open cell foam material by: 
 (a) forming a first pre-gelled starch suspension that is maintained at a low temperature;    (b) mixing together wood fibers or flour (having an aspect ratio between approximately 1:2 and 1:8), a second pre-gelled starch suspension to form a homogeneous composition, and a source of gas;    (c) adding to the first pre-gelled starch suspension a dry or damp, homogeneous mixture containing the wood fibers and second pre-gelled starch; and    (d) molding the homogeneous composition with heat to form a biodegradable material.    
   
   
       35 . A process for forming an open cell foam material by: 
 (a) forming a pre-gelled starch suspension produced from approximately 3-5% potato starch (by weight of the pre-gel) and approximately 95-97% water (by weight of the pre-gel) such that the pre-gelled suspension is maintained at low temperatures;    (b) mixing together wood fibers or flour (having an aspect ratio between approximately 1:2 and 1:8), a second pre-gelled starch suspension (the second pre-gel) produced from approximately 15% corn starch (by weight of the second pre-gel) and approximately 85% water (by weight of the second pre-gel), and baking powder of 0.4-12% baking powder (by weight of the homogeneous moldable composition) to form a homogeneous mixture;    (c) adding to the pre-gelled potato starch suspension a homogeneous mixture containing the wood fibers and pre-gelled corn starch to form a homogeneous moldable composition; and    (d) molding the homogeneous moldable composition with heat to form a biodegradable material.    
   
   
       36 . The material of  claim 20  in the form of a cup.  
   
   
       37 . The material of  claim 20  in the form of a tray.  
   
   
       38 . The material of  claim 20  in the form of a bowl.  
   
   
       39 . The material of  claim 20  in the form of a plate.  
   
   
       40 . The material of  claim 20  in the form of a utensil.