Methods for manufacturing molded sheets having a high starch content

• US 5,810,961 A
• Filed: 04/09/1996
• Issued: 09/22/1998
• Est. Priority Date: 11/19/1993
• Status: Expired due to Fees

• Current Assignee: E. Khashoggi Industries, LLC
• Original Assignee: E. Khashoggi Industries, LLC
• Inventors: Andersen, Per Just, Hodson, Simon K., Ong, Shaode, Christiansen, Bruce J.
• Primary Examiner(s): AFTERGUT, KAREN K
• Application Number:
  US08/631,676
• Time in Patent Office: 896 Days
• Field of Search: 264/145, 264/42, 264/131, 264/132, 264/133, 264/148, 264/154, 264/160, 264/177.11, 264/175, 264/211.11, 264/282, 264/286, 264/295, 156/324, 427/393.6
• US Class Current: 156/324
• CPC Class Codes: B05B 11/10 Pump arrangements for transferring the contents from the container to a pump chamber by a sucking effect and forcing the contents out through the dispensing nozzle
• CPC Class Codes: B05C 5/0245 for applying liquid or other fluent material to a moving work of indefinite length, e.g. to a moving web B05C5/0241, B05C5/0254, B05C5/027, B05C5/0283 take precedence
• CPC Class Codes: B27N 1/02 Mixing the material with binding agent mixing in general B01F
• CPC Class Codes: B27N 3/002 characterised by the type of binder compositions of macromolecular compounds C08L
• CPC Class Codes: B27N 3/007 and at least partly composed of recycled material
• CPC Class Codes: B27N 3/18 Auxiliary operations, e.g. preheating, humidifying, cutting-off
• CPC Class Codes: B27N 3/28 characterised by using extrusion presses
• CPC Class Codes: B28B 1/00 Producing shaped prefabricated articles from the material using presses B28B3/00; shaping on moving conveyors B28B5/00; producing tubular articles B28B21/00 ; producing articles with embedded elements B28B23/00
• CPC Class Codes: B28B 1/52 specially adapted for producing articles from mixtures containing fibres, e.g. asbestos cementby wrapping on to mandrels B28B1/42
• CPC Class Codes: B28B 11/00 Apparatus or processes for treating or working the shaped or preshaped articles specially adapted for tubular articles B28B21/92; decoration or surface treatment in general B05, B44; compacting concrete in situ in connection with building E04G21/06; drying F26
• CPC Class Codes: B28B 11/003 the shaping of preshaped articles, e.g. by bending B28B11/08 takes precedence
• CPC Class Codes: B28B 23/00 Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objectsB28B21/00 takes precedence; in units for prefabricated buildings B28B7/22
• CPC Class Codes: B28B 23/0081 Embedding aggregates to obtain particular properties
• CPC Class Codes: B28B 23/0087 Lightweight aggregates for making lightweight articles
• CPC Class Codes: B28B 3/126 on material passing directly between the co-operating rollers
• CPC Class Codes: B28B 3/20 wherein the material is extruded extrusion moulding of plastics B29C48/00
• CPC Class Codes: B29C 2043/3433 using dispensing heads, e.g. extruders, placed over or apart from the moulds
• CPC Class Codes: B29C 2043/463 corrugated, patterned or embossed surface
• CPC Class Codes: B29C 2049/023 using inherent heat of the preform, i.e. 1 step blow moulding
• CPC Class Codes: B29C 2791/006 Using vacuum
• CPC Class Codes: B29C 2795/007 : after shaping
• CPC Class Codes: B29C 2949/0715 : the preform having one end closed
• CPC Class Codes: B29C 43/00 : Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor by liberation of internal stresses B29C61/006
• CPC Class Codes: B29C 43/003 : characterised by the choice of material
• CPC Class Codes: B29C 43/08 : with circular movement , e.g. mounted on rolls, turntables
• CPC Class Codes: B29C 43/22 : of articles of indefinite length
• CPC Class Codes: B29C 43/222 : characterised by the shape of the surface
• CPC Class Codes: B29C 43/24 : Calendering
• CPC Class Codes: B29C 43/34 : Feeding the material to the mould or the compression means B29C43/085 takes precedence
• CPC Class Codes: B29C 43/46 : Rollers
• CPC Class Codes: B29C 44/0407 : by regulating the temperature of the mould or parts thereof, e.g. cold mould walls inhibiting foaming of an outer layer
• CPC Class Codes: B29C 45/0013 : using fillers dispersed in the moulding material, e.g. metal particles
• CPC Class Codes: B29C 48/0017 : combined with blow-moulding or thermoforming
• CPC Class Codes: B29C 48/022 : characterised by the choice of material
• CPC Class Codes: B29C 48/05 : Filamentary, e.g. strands
• CPC Class Codes: B29C 48/08 : flexible, e.g. films
• CPC Class Codes: B29C 48/09 : Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 48/13 : Articles with a cross-section varying in the longitudinal direction, e.g. corrugated pipes
• CPC Class Codes: B29C 48/15 : incorporating preformed parts or layers, e.g. extrusion moulding around inserts
• CPC Class Codes: B29C 48/38 : using two or more serially arranged screws in the same barrel
• CPC Class Codes: B29C 48/465 : using rollers
• CPC Class Codes: B29C 48/91 : Heating, e.g. for cross linking
• CPC Class Codes: B29C 49/0005 : characterised by the material
• CPC Class Codes: B29C 49/04 : Extrusion blow-moulding
• CPC Class Codes: B29C 49/06 : Injection blow-moulding
• CPC Class Codes: B29C 49/063 : with the parison axis held in the plane of rotation
• CPC Class Codes: B29C 49/0691 : using sheet like material, e.g. sheet blow-moulding from joined sheets
• CPC Class Codes: B29C 51/002 : characterised by the choice of material
• CPC Class Codes: B29C 51/04 : Combined thermoforming and prestretching, e.g. biaxial stretching
• CPC Class Codes: B29C 51/08 : Deep drawing or matched-mould forming, i.e. using mechanical means only
• CPC Class Codes: B29C 51/082 : by shaping between complementary mould parts
• CPC Class Codes: B29C 51/10 : Forming by pressure difference, e.g. vacuum
• CPC Class Codes: B29C 53/063 : combined with folding
• CPC Class Codes: B29C 53/58 : helically
• CPC Class Codes: B29C 55/18 : by squeezing between surfaces, e.g. rollers
• CPC Class Codes: B29C 67/24 : characterised by the choice of material
• CPC Class Codes: B29C 67/242 : Moulding mineral aggregates bonded with resin, e.g. resin concrete shaping ceramic compositions without binder or water-setting cementitious material B28B; compositions per se C04B
• CPC Class Codes: B29C 70/50 : for producing articles of indefinite length, e.g. prepregs, sheet moulding compounds [SMC] or cross moulding compounds [XMC]
• CPC Class Codes: B29C 71/0009 : using liquids, e.g. solvents, swelling agents spectacle cases, e.g. for cleaning contact lenses A45C11/04; disinfecting or sterilising contact lenses A61L12/00, using liquid substances A61L2/20; cleaning involving the use of liquid in general B08B3/00; for hydrating contact lenses B29D11/00067
• CPC Class Codes: B29K 2001/00 : Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
• CPC Class Codes: B29K 2003/00 : Use of starch or derivatives as moulding material
• CPC Class Codes: B29K 2005/00 : Use of polysaccharides or derivatives as moulding material
• CPC Class Codes: B29K 2089/00 : Use of proteins, e.g. casein, gelatine or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2105/06 : containing reinforcements, fillers or inserts
• CPC Class Codes: B29K 2105/12 : of short lengths, e.g. chopped filaments, staple fibres or bristles
• CPC Class Codes: B29K 2105/16 : Fillers
• CPC Class Codes: B29K 2995/006 : Bio-degradable, e.g. bioabsorbable, bioresorbable or bioerodible
• CPC Class Codes: B29L 2024/00 : Articles with hollow walls
• CPC Class Codes: B29L 2031/608 : Honeycomb structures
• CPC Class Codes: B29L 2031/712 : Containers; Packaging elements or accessories, Packages closures therefor B29L2031/56; ink or toner cartridges B29L2031/7678; squeeze tubes B29L2023/20; suitcases B29L2031/7418
• CPC Class Codes: B29L 2031/7132 : Bowls, Cups, Glasses
• CPC Class Codes: B31B 2105/0022 : Making boxes from tubular webs or blanks, e.g. with separate bottoms, including tube or bottom forming operations
• CPC Class Codes: B31B 50/32 : in circular paths
• CPC Class Codes: B31D 1/005 : making bottoms or caps
• CPC Class Codes: B32B 13/02 : with fibres or particles being present as additives in the layer
• CPC Class Codes: B32B 23/04 : comprising such cellulosic plastic substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material next to a glass layer B32B17/08
• CPC Class Codes: B32B 23/22 : comprising ethers
• CPC Class Codes: B32B 2307/7163 : Biodegradable
• CPC Class Codes: B32B 2439/00 : Containers; Receptacles
• CPC Class Codes: B32B 27/04 : as impregnant, bonding, or embedding substance not used
• CPC Class Codes: B32B 27/20 : using fillers, pigments, thixotroping agents
• CPC Class Codes: B32B 3/28 : characterised by a layer comprising a deformed thin sheet , i.e. the layer having its entire thickness deformed out of the plane, e.g. corrugated, crumpled B32B29/08 takes precedence
• CPC Class Codes: B32B 37/00 : Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
• CPC Class Codes: B32B 37/12 : characterised by using adhesives
• CPC Class Codes: B32B 37/144 : using layers with different mechanical or chemical conditions or properties, e.g. layers with different thermal shrinkage, layers under tension during bonding constructional features for tensioning B32B38/1825
• CPC Class Codes: B32B 5/02 : characterised by structural features of a fibrous or filamentary layer layer formed of metallic wires B32B15/02; layer formed of natural mineral fibres B32B19/02; layer formed of wood fibres B32B21/02
• CPC Class Codes: B32B 5/18 : characterised by features of a layer of foamed material
• CPC Class Codes: B32B 9/00 : Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
• CPC Class Codes: B32B 9/02 : comprising animal or vegetable substances , e.g. cork, bamboo, starch
• CPC Class Codes: B32B 9/04 : comprising such particular substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material next to a glass layer B32B17/06; layered products with at least two ceramic layers composed mainly of ceramic B32B18/00
• CPC Class Codes: B65D 2565/385 : especially suited for or with means facilitating recycling
• CPC Class Codes: B65D 43/162 : the container, the lid and the hinge being made of one piece B65D43/161 takes precedence
• CPC Class Codes: B65D 65/38 : Packaging materials of special type or form
• CPC Class Codes: B65D 65/466 : Bio- or photodegradable packaging materials
• CPC Class Codes: C04B 14/06 : Quartz; Sand
• CPC Class Codes: C04B 14/10 : Clay sepiolite C04B14/042; grog C04B18/025
• CPC Class Codes: C04B 14/16 : porous, e.g. pumice
• CPC Class Codes: C04B 14/18 : Perlite
• CPC Class Codes: C04B 14/20 : Mica; Vermiculite mechanical splitting B28D
• CPC Class Codes: C04B 14/202 : Vermiculite
• CPC Class Codes: C04B 14/24 : porous, e.g. foamed glass
• CPC Class Codes: C04B 14/28 : of calcium
• CPC Class Codes: C04B 14/303 : Alumina
• CPC Class Codes: C04B 14/365 : Gypsum synthetic gypsum C04B18/0445, C04B18/064
• CPC Class Codes: C04B 14/386 : Carbon carbon nanotubes C04B14/026
• CPC Class Codes: C04B 14/42 : Glass
• CPC Class Codes: C04B 14/46 : Rock wool ; Ceramic or silicate fibres C04B14/40, C04B14/42 take precedence
• CPC Class Codes: C04B 14/48 : Metal
• CPC Class Codes: C04B 18/248 : from specific plants, e.g. hemp fibres
• CPC Class Codes: C04B 24/14 : Peptides; Proteins; Derivatives thereof
• CPC Class Codes: C04B 24/2623 : Polyvinylalcohols; Polyvinylacetates
• CPC Class Codes: C04B 24/2652 : Nitrogen containing polymers, e.g. polyacrylamides, polyacrylonitriles
• CPC Class Codes: C04B 24/32 : Polyethers, e.g. alkylphenol polyglycolether
• CPC Class Codes: C04B 24/383 : Cellulose or derivatives thereof
• CPC Class Codes: C04B 26/00 : Compositions of mortars, concrete or artificial stone, containing only organic binders , e.g. polymer or resin concrete mechanical aspects of moulding polymer or resin concrete B29C67/242
• CPC Class Codes: C04B 26/02 : Macromolecular compounds
• CPC Class Codes: C04B 26/28 : Polysaccharides or derivatives thereof
• CPC Class Codes: C08J 2303/02 : Starch; Degradation products thereof, e.g. dextrin
• CPC Class Codes: C08J 2323/02 : not modified by chemical after treatment
• CPC Class Codes: C08J 5/18 : Manufacture of films or sheets
• CPC Class Codes: C08L 1/286 : substituted with acid radicals, e.g. carboxymethyl cellulose [CMC] C08L1/282 takes precedence
• CPC Class Codes: C08L 2666/02 : Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 3/02 : Starch; Degradation products thereof, e.g. dextrin
• CPC Class Codes: C08L 5/12 : Agar or agar-agar , i.e. mixture of agarose and agaropectin; Derivatives thereof
• CPC Class Codes: E05D 1/02 : made of one piece
• CPC Class Codes: E05Y 2999/00 : Subject-matter not otherwise provided for in this subclass
• CPC Class Codes: Y02A 40/90 : in food processing or handling, e.g. food conservation
• CPC Class Codes: Y02W 30/91 : Use of waste materials as fillers for mortars or concrete
• CPC Class Codes: Y02W 90/10 : Bio-packaging, e.g. packing containers made from renewable resources or bio-plastics

Abstract

Compositions and methods for manufacturing sheets having a starch-bound matrix reinforced with fibers and optionally including an inorganic mineral filler. Suitable mixtures for forming the sheets are prepared by mixing together water, unmodified and ungelatinized starch granules, a cellulosic ether, fibers, and optionally an inorganic mineral filler in the correct proportions to form a sheet having desired properties. The mixtures are formed into sheets by passing them between one or more sets of heated rollers to form green sheets. The heated rollers cause the cellulosic ether to form a skin on the outer surfaces of the sheet that prevents the starch granules from causing the sheet to adhere to the rollers upon gelation of the starch. The green sheets are passed between heated rollers to gelatinize the starch granules, and then to dry the sheet by removing a substantial portion of the water by evaporation. The starch and cellulosic ether form the binding matrix of the sheets with the fibers and optional inorganic filler dispersed throughout the binding matrix. The starch-bound sheets can be cut, rolled, pressed, scored, perforated, folded, and glued to fashion articles from the sheets much like paper or paperboard. The sheets are particularly useful in the mass production of containers, such as food and beverage containers.

Claims

1. A method for manufacturing a starch-bound sheet comprising the steps of:

(a) mixing together water, substantially ungelatinized starch granules, a cellulosic ether, a fibrous material, and optionally an inorganic aggregate filler to form a moldable mixture;

(b) forming the moldable mixture into an initial green sheet by passing the mixture between at least one set of forming rollers having a temperature such that at least a portion of the cellulosic ether forms a skin on outer surfaces of the initial green sheet such that the initial green sheet does not substantially adhere to the forming rollers upon gelatinization of the starch granules;

(c) passing the initial green sheet between at least one set of rollers having a temperature such that at least a portion of the starch granules become substantially gelatinized in order to form an intermediate green sheet; and

(d) heating the intermediate green sheet in order to remove a substantial portion of the water from the intermediate green sheet so as to form a substantially hardened sheet having a binding matrix including substantially dried starch and cellulosic ether.

2. A method as defined in claim 1, wherein steps (c) and (d) are performed by successive sets of rollers having increasing temperatures from one set of rollers to a next set of rollers.

3. A method as defined in claim 1, wherein steps (c) and (d) are performed by successive sets of rollers having substantially the same temperature from one set of rollers to a next set of rollers.

5. A method as defined in claim 1, wherein the cellulosic ether has a thermal precipitation temperature and wherein the forming rollers of step (b) have a temperature that is at least as high as the thermal precipitation temperature of the cellulosic ether.

6. A method as defined in claim 5, wherein the starch granules have a gelation temperature and wherein the forming rollers of step (b) have a temperature such that the starch granules within the moldable mixture remain substantially ungelatinized until step (c).

7. A method as defined in claim 6, wherein the forming rollers utilized in step (b) have a temperature that is less than the gelation temperature of the starch granules.

8. A method as defined in claim 1, wherein the starch granules have a gelation temperature and wherein the forming rollers of step (b) have a temperature such that at least a portion of the starch granules within the moldable mixture become partially gelatinized.

9. A method as defined in claim 1, wherein the starch granules have a concentration in a range from about 5% to about 90% by weight of total solids in the moldable mixture.

10. A method as defined in claim 1, wherein the starch granules have a concentration in a range from about 15% to about 80% by weight of total solids in the moldable mixture.

11. A method as defined in claim 1, wherein the starch granules have a concentration in a range from about 30% to about 70% by weight of total solids in the moldable mixture.

12. A method as defined in claim 1, wherein the starch granules comprise potato starch.

13. A method as defined in claim 1, wherein the starch granules comprise corn starch.

14. A method as defined in claim 1, wherein the starch granules comprise waxy corn starch.

15. A method as defined in claim 1, wherein the cellulosic ether has a concentration in a range from about 0.5% to about 10% by weight of total solids in the moldable mixture.

16. A method as defined in claim 1, wherein the cellulosic ether has a concentration in a range from about 1% to about 5% by weight of total solids in the moldable mixture.

17. A method as defined in claim 1, wherein the cellulosic ether has a concentration in a range from about 2% to about 4% by weight of total solids in the moldable mixture.

18. A method as defined in claim 1, wherein the cellulosic ether is selected from the group consisting of methylhydroxyethylcellulose, hydroxymethylethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxyethylpropylcellulose, and mixtures or derivatives thereof.

19. A method as defined in claim 1, wherein the inorganic aggregate filler has a concentration in a range from about 0% to about 90% by weight of total solids in the moldable mixture.

20. A method as defined in claim 1, wherein the inorganic aggregate filler has a concentration in a range from about 20% to about 80% by weight of total solids in the moldable mixture.

21. A method as defined in claim 1, wherein the inorganic aggregate filler has a concentration in a range from about 30% to about 70% by weight of total solids in the moldable mixture.

22. A method as defined in claim 1, wherein the inorganic aggregate filler is selected from the group consisting of clay, gypsum, calcium carbonate, mica, silica, alumina, sand, gravel, sandstone, limestone, and mixtures thereof.

23. A method as defined in claim 1, wherein the inorganic aggregate filler comprises individual particles that are size optimized in order to achieve a predetermined natural packing density.

24. A method as defined in claim 23, wherein the natural packing density of the inorganic aggregate filler is greater than about 0.65.

25. A method as defined in claim 1, wherein the inorganic aggregate filler is selected from the group consisting of perlite, vermiculite, hollow glass spheres, porous ceramic spheres, pumice, and mixtures thereof.

26. A method as defined in claim 1, wherein the fibrous material has a concentration in a range from about 3% to about 40% by weight of total solids in the moldable mixture.

27. A method as defined in claim 1, wherein the fibrous material has a concentration in a range from about 5% to about 30% by weight of total solids in the moldable mixture.

28. A method as defined in claim 1, wherein the fibrous material has a concentration in a range from about 7% to about 20% by weight of total solids in the moldable mixture.

29. A method as defined in claim 1, wherein the fibrous material comprises organic fibers selected from the group consisting of hemp fibers, cotton fibers, bagasse fibers, abaca fibers, flax, southern pine fibers, southern hardwood fibers, and mixtures thereof.

30. A method as defined in claim 1, wherein the fibrous material includes inorganic fibers selected from the group consisting of glass fibers, silica fibers, ceramic fibers, carbon fibers, metal fibers, and mixtures thereof.

31. A method as defined in claim 1, wherein the fibrous material includes individual fibers having an aspect ratio of at least about 10:

1.

32. A method as defined in claim 1, wherein the fibrous material includes individual fibers having an aspect ratio of at least about 100:

1.

33. A method as defined in claim 1, wherein the moldable mixture further includes a protein-based binder selected from the group consisting of prolamine, collagen, gelatin, glue, casein, and mixtures or derivatives thereof.

34. A method as defined in claim 1, wherein the moldable mixture further includes a polysaccharide selected from the group consisting of alginic acid, phycocolloids, agar, gum arabic, guar gum, locust bean gum, gum karaya, gum tragacanth, and mixtures or derivatives thereof.

35. A method as defined in claim 1, wherein the moldable mixture further includes a synthetic organic binder selected from the group consisting of polyvinyl pyrrolidone, polyethylene glycol, polyvinyl alcohol, polyvinylmethyl ether, polyacrylic acids, polyacrylic acid salts, polyvinylacrylic acids, polyvinylacrylic acid salts, polyacrylimides, polylactic acid, ethylene oxide polymers, latex, and mixtures or derivatives thereof.

36. A method as defined in claim 1, wherein the moldable mixture has yield stress greater than about 2 kPa.

37. A method as defined in claim 1, wherein the moldable mixture has yield stress greater than about 100 kPa.

38. A method as defined in claim 1, wherein the starch granules have a gelation temperature and the cellulosic ether has a thermal precipitation temperature, wherein the gelation temperature of the starch granules is greater than the thermal precipitation temperature of the cellulosic ether.

39. A method as defined in claim 1, wherein the water has a concentration in a range from about 5% to about 80% by weight of the moldable mixture.

40. A method as defined in claim 1, wherein the water has a concentration in a range from about 10% to about 70% by weight of the moldable mixture.

41. A method as defined in claim 1, wherein the water has a concentration in a range from about 20% to about 50% by weight of the moldable mixture.

42. A method as defined in claim 1, wherein the moldable mixture further includes a plasticizer.

43. A method as defined in claim 1, further including the step of treating the substantially hardened sheet with glycerin.

44. A method as defined in claim 43, wherein the glycerin is mixed with water.

45. A method as defined in claim 1, wherein the substantially hardened sheet has a thickness up to about 10 cm.

46. A method as defined in claim 1, wherein the substantially hardened sheet has a thickness less than about 1 cm.

47. A method as defined in claim 1, wherein the substantially hardened sheet has a thickness less than about 5 mm.

48. A method as defined in claim 1, wherein the substantially hardened sheet has a thickness less than about 3 mm.

49. A method as defined in claim 1, wherein the substantially hardened sheet has a thickness less than about 1 mm.

50. A method as defined in claim 1, wherein the method yields sheets wherein the fibrous material includes individual fibers having a substantially random orientation within the sheet.

51. A method as defined in claim 1, wherein the method yields sheets wherein the fibrous material includes individual fibers having a substantially unidirectional orientation within the sheet.

52. A method as defined in claim 1, wherein the method yields sheets wherein the fibrous material includes individual fibers having a substantially bidirectional orientation within the sheet.

53. A method as defined in claim 1, wherein the method yields a sheet having a tensile strength to density ratio in a range from about 2 MPa.cm³ /g to about 500 MPa.cm³ /g.

54. A method as defined in claim 1, wherein the method yields a sheet having a tensile strength to density ratio in a range from about 5 MPa.cm³ /g to about 150 MPa.cm³ /g.

55. A method as defined in claim 1, wherein the method yields a sheet having a tensile strength in a range from about 0.05 MPa to about 100 MPa.

56. A method as defined in claim 1, wherein the method yields a sheet having a tensile strength in a range from about 5 MPa to about 80 MPa.

57. A method as defined in claim 1, wherein the method yields a sheet having a density greater than about 1 g/cm³.

58. A method as defined in claim 1, wherein the method yields a sheet having a density greater than about 1.5 g/cm³.

59. A method as defined in claim 1, wherein the method yields a sheet that is capable of being elongated in a range from about 0.5% to about 12% without completely fracturing.

60. A method as defined in claim 1, wherein the method yields a sheet that is water degradable.

61. A method as defined in claim 1, further including the step of corrugating the substantially hardened sheet.

62. A method as defined in claim 1, further including the step of creping the substantially hardened sheet.

63. A method as defined in claim 1, further including the step of parchmenting the substantially hardened sheet.

64. A method as defined in claim 1, further including the step of applying a coating to the substantially hardened sheet.

65. A method as defined in claim 1, further including the step of laminating at least one additional sheet to the substantially hardened sheet.

66. A method as defined in claim 1, further including the step of applying an indicia to the substantially hardened sheet.

67. A method as defined in claim 1, further including the step of forming a hinge in the substantially hardened sheet.

68. A method as defined in claim 1, further including the step of forming a perforation in the substantially hardened sheet.

69. A method as defined in claim 1, further including the step of fashioning the substantially hardened sheet into a container.

70. A method as defined in claim 1, further including the step of winding the substantially hardened sheet onto a spool.

71. A method as defined in claim 1, further including the step of cutting the substantially hardened sheet into smaller sheet segments.

72. A method as defined in claim 1, further including the step of heating the substantially hardened sheet in order to thermoform it into a desired shape.

73. A method as defined in claim 1, further including the step of remoistening the substantially hardened sheet.

74. A method as defined in claim 1, further including the step of spiral winding the substantially hardened sheet into a desired shape.

78. A method as defined in claim 1, further including the step of fashioning the substantially hardened sheet into a desired shape of an article of manufacture.

79. A method as defined in claim 1, wherein the moldable mixture further includes a cross-linking admixture.

80. A method as defined in claim 79, wherein the cross-linking admixture is selected from the group consisting of dialdehydes, methylureas, and melamine formaldehyde resins.

81. A method as defined in claim 1, wherein the inorganic aggregate filler is selected from the group consisting of rock, glass beads, aerogels, xerogels, fly ash, fumed silica, fused silica, tabular alumina, kaoline, microspheres, calcium aluminate, xonotlite, lightweight expanded clays, hydrated hydraulic cement particles, waste concrete products, exfoliated rock, silica gel, calcium silicate gel, and aluminum silicate gel.

82. A method as defined in claim 1, wherein the inorganic aggregate filler is selected from the group consisting of metal balls, filings, pellets, powders, and mixtures thereof.

83. A method as defined in claim 1, wherein the moldable mixture further includes an organic aggregate selected from the group consisting of seagel, synthetic clay, cork, seeds, lightweight polymers, agar materials, gelatins, and mixtures thereof.

84. A method as defined in claim 1, further including the step of incorporating interstitial voids within the binding matrix of the substantially hardened sheet.

85. A method as defined in claim 1, wherein step (b) further includes extruding the moldable mixture through a die prior to passing the mixture between the forming rollers.

86. A method as defined in claim 1, wherein the substantially ungelatinized starch granules comprise two or more different starches having varying gelation temperatures.

87. A method as defined in claim 1, further including the step of compacting the substantially hardened sheet by passing the sheet between at least one pair of compaction rollers.

88. A method as defined in claim 1, further including the step of passing the substantially hardened sheet between at least one pair of calendering rollers.

89. A method as defined in claim 1, further including the step of passing the substantially hardened sheet between at least one pair of finishing rollers to impart a desired surface finish.

90. A method as defined in claim 64, wherein the coating is applied by a process selected from the group consisting of blade coating, puddle coating, air-knife coating, printing coating, dahlgren coating, gravure coating, and powder coating.

91. A method as defined in claim 64, wherein the coating is selected from the group consisting of edible oils, melamine, polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, polyacrylates, polyamides, hydroxypropylmethylcellulose, polyethylene glycol, acrylics, polyurethane, polyethylene, polylactic acid, polyhydroxybutyrate-hydroxyvalerate copolymers, latex, starches, soybean protein, soybean oil, cellulosic ethers, synthetic polymers, waxes, elastomers, sodium silicates, calcium carbonate, aluminum oxide, silicone oxide, kaoline clay, ceramic, and mixtures thereof.

92. A method as defined in claim 65, wherein the at least one additional sheet is selected from the group consisting of starch-bound sheets, organic polymer sheets, metal foil sheets, ionomer sheets, elastomeric sheets, plastic sheets, fibrous sheets, mats, paper sheets, cellophane sheets, nylon sheets, wax sheets, hydraulically settable sheets, highly inorganically filled sheets, metalized film sheets, and combinations of the foregoing.

93. A method as defined in claim 65, wherein the at least one additional sheet is laminated to the substantially hardened sheet by a process selected from the group consisting of wet-bond laminating, dry-bond laminating, thermal laminating, and pressure laminating.

94. A method as defined in claim 1, wherein steps (b)-(d) occur substantially simultaneously.

4. A method for manufacturing a starch-bound sheet comprising the steps of:

(a) mixing together water, substantially ungelatinized starch granules, a cellulosic ether, a fibrous material, and optionally an inorganic aggregate filler to form a moldable mixture;

(b) forming the moldable mixture into an initial green sheet by passing the mixture between at least one set of forming rollers having a temperature such that at least a portion of the cellulosic ether is caused to substantially thermally precipitate on outer surfaces of the initial green sheet in order that the initial green sheet does not substantially adhere to the forming rollers upon gelatinization of the starch granules; and

(c) passing the initial green sheet between at least one set of heated rollers having a temperature such that at least a portion of the starch granules become substantially gelatinized and in order to remove a substantial portion of the water from the initial green sheet so as to form a substantially hardened sheet having a binding matrix including substantially dried starch and cellulosic ether.

75. A method for manufacturing a starch-bound sheet comprising the steps of:

(a) mixing together water, substantially ungelatinized starch granules having a gelation temperature, a cellulosic ether having a thermal precipitation temperature, a fibrous material, and optionally an inorganic aggregate filler to form a moldable mixture;

(b) forming the moldable mixture into an initial green sheet by passing the mixture between at least one set of forming rollers having a temperature at or above the thermal precipitation temperature of the cellulosic ether such that at least a portion of the cellulosic ether forms a skin on outer surfaces of the initial green sheet and such that the initial green sheet does not substantially adhere to the forming rollers upon gelatinization of the starch granules;

(c) passing the initial green sheet between at least one set of rollers having a temperature greater than the gelation temperature of the starch granules such that at least a portion of the starch granules become substantially gelatinized in order to form an intermediate green sheet; and

(d) heating the intermediate green sheet in order to remove a substantial portion of the water from the intermediate green sheet so as to form a substantially hardened sheet having a binding matrix including substantially dried starch and cellulosic ether.

76. A method for manufacturing a starch-bound sheet comprising the steps of:

(a) mixing together water, substantially ungelatinized starch granules having a gelation temperature, a cellulosic ether having a thermal precipitation temperature, a fibrous material, and optionally an inorganic aggregate filler to form a moldable mixture having a yield stress greater than about 2 kPa, the starch granules having a concentration in a range from about 5% to about 90% by weight of total solids within the moldable mixture, the cellulosic ether having a concentration in a range from about 0.5% to about 10% by weight of solids within the moldable mixture, the fibers having a concentration in a range from about 3% to about 40% by weight of total solids within the moldable mixture, the optional inorganic aggregate filler having a concentration in a range from about 0% to about 90% by weight of total solids within the moldable mixture;

(b) forming the moldable mixture into an initial green sheet by passing the mixture between at least one set of forming rollers having a temperature at or above the thermal precipitation temperature of the cellulosic ether such that at least a portion of the cellulosic ether forms a skin on outer surfaces of the initial green sheet and such that the initial green sheet does not substantially adhere to the forming rollers upon gelatinization of the starch granules;

(c) passing the initial green sheet between at least one set of rollers having a temperature greater than the gelation temperature of the starch granules such that at least a portion of the starch granules become substantially gelatinized in order to form an intermediate green sheet; and

(d) heating the intermediate green sheet in order to remove a substantial portion of the water from the intermediate green sheet so as to form a substantially hardened sheet having a binding matrix including substantially dried starch and cellulosic ether.

77. A method for manufacturing a starch-bound sheet comprising the steps of:

(a) mixing together water, substantially ungelatinized starch granules, a cellulosic ether, a fibrous material, and optionally an inorganic aggregate filler to form a moldable mixture; and

(b) forming the moldable mixture into the starch-bound sheet by passing the mixture between at least one set of heated forming rollers having a temperature in order that at least a portion of the cellulosic ether substantially thermally precipitates on outer surfaces of the sheet such that the sheet does not substantially adhere to the forming rollers upon gelatinization of the starch granules and in order to substantially gelatinize at least a portion of the starch granules and remove a substantial portion of the water from the sheet by evaporation so as to form the starch-bound sheet having a binding matrix including substantially dried starch and cellulosic ether.