Methods for uniformly dispersing fibers within starch-based compositions

• US 5,618,341 A
• Filed: 05/12/1995
• Issued: 04/08/1997
• Est. Priority Date: 08/11/1992
• Status: Expired due to Term

• Current Assignee: E. Khashoggi Industries, LLC
• Original Assignee: E. Khashoggi Industries, LLC
• Inventors: Hodson, Simon K., Andersen, Per J.
• Primary Examiner(s): BRUNSMAN, DAVID M
• Application Number:
  US08/439,877
• Time in Patent Office: 697 Days
• Field of Search: 106/163.1, 106/209, 106/162.5, 106/162.51, 106/164.01, 106/205.01, 106/206.1, 106/287.35
• US Class Current: 106/287.35
• CPC Class Codes: B05C 1/0826 the work being a web or sheets B05C1/0804, B05C1/0808, B05C1/0813, B05C1/0817, B05C1/0821, B05C1/10, B05C1/12 take precedence
• CPC Class Codes: B05C 1/0834 the coating roller co-operating with other rollers, e.g. dosing, transfer rollers
• CPC Class Codes: B05C 3/18 only one side of the work coming into contact with the liquid or other fluent material B05C3/02 takes precedence
• 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: 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 11/008 Blow moulding, e.g. with or without the use of a membrane
• CPC Class Codes: B28B 13/021 by fluid pressure acting directly on the material, e.g. using vacuum, air pressure
• CPC Class Codes: B28B 13/06 Removing the shaped articles from moulds by means incorporated in, or carried by, the moulds B28B7/10
• 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 3/00 Producing shaped articles from the material by using presses shaping on moving conveyors B28B5/00; Presses specially adapted therefor presses in general B30B
• CPC Class Codes: B28B 3/02 wherein a ram exerts pressure on the material in a moulding space; Ram heads of special form
• 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: B28B 3/2645 using means for inserting reinforcing members
• CPC Class Codes: B28B 7/42 for heating or cooling, e.g. steam jackets , by means of treating agents acting directly on the moulding material
• CPC Class Codes: B28C 7/02 : Controlling the operation of the mixing
• CPC Class Codes: B29C 2795/007 : after shaping
• 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 44/3402 : Details of processes or apparatus for reducing environmental damage or for working-up compositions comprising inert blowing agents or biodegradable components
• CPC Class Codes: B29C 48/0011 : combined with compression moulding
• CPC Class Codes: B29C 48/03 : characterised by the shape of the extruded material at extrusion
• CPC Class Codes: B29C 48/15 : incorporating preformed parts or layers, e.g. extrusion moulding around inserts
• CPC Class Codes: B29C 49/6605 : Heating the article, e.g. for hot fill
• CPC Class Codes: B29C 51/04 : Combined thermoforming and prestretching, e.g. biaxial stretching
• 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 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 2093/00 : Use of natural resins, e.g. shellac, or derivatives thereof, as moulding material B29K2001/00, B29K2003/00, B29K2005/00, B29K2007/00 and B29K2089/00 take precedence
• 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: B29L 2024/00 : Articles with hollow walls
• CPC Class Codes: B29L 2031/608 : Honeycomb structures
• 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 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 37/12 : characterised by using adhesives
• 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 5/14 : characterised by a layer differing constitutionally or physically in different parts, e.g. denser near its faces
• CPC Class Codes: B32B 5/18 : characterised by features of a layer of foamed material
• CPC Class Codes: B65D 2565/385 : especially suited for or with means facilitating recycling
• 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 16/02 : Cellulosic materials cellulosic waste materials, e.g. sawdust, rice husks, C04B18/24
• CPC Class Codes: C04B 20/0048 : Fibrous materials
• 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 26/026 : Proteins or derivatives thereof
• CPC Class Codes: C04B 26/28 : Polysaccharides or derivatives thereof
• CPC Class Codes: C04B 28/00 : Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
• CPC Class Codes: C04B 40/00 : Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability active ingredients C04B22/00 - C04B24/00; hardening of a well-defined composition C04B26/00 - C04B28/00; making porous, cellular or lightening C04B38/00; mechanical aspects B28, e.g. conditioning the materials prior to shaping B28B17/02
• CPC Class Codes: C04B 40/005 : High shear mixing; Obtaining macro-defect free materials
• CPC Class Codes: C04B 40/006 : involving the elimination of excess water from the mixture
• CPC Class Codes: C04B 41/61 : Coating or impregnation
• CPC Class Codes: C08L 1/28 : Alkyl ethers
• 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 2666/04 : Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 3/00 : Compositions of starch, amylose or amylopectin or of their derivatives or degradation products
• CPC Class Codes: C08L 3/02 : Starch; Degradation products thereof, e.g. dextrin
• CPC Class Codes: C08L 5/02 : Dextran; Derivatives thereof
• CPC Class Codes: C08L 5/12 : Agar or agar-agar , i.e. mixture of agarose and agaropectin; Derivatives thereof
• CPC Class Codes: C08L 5/14 : Hemicellulose; Derivatives thereof
• CPC Class Codes: C08L 89/06 : derived from leather or skin , e.g. gelatin
• CPC Class Codes: C08L 97/02 : Lignocellulosic material, e.g. wood, straw or bagasse manufacture of articles made from lignocellulosic material by dry processes B27N
• CPC Class Codes: Y02W 90/10 : Bio-packaging, e.g. packing containers made from renewable resources or bio-plastics

Abstract

Compositions and methods for substantially uniformly dispersing fibers throughout a starch-based composition. The fibers are dispersed throughout the composition by means of a high yield stress, high viscosity fluid fraction formed by interacting together water and a thickening agent such as gelatinized starch. The well-dispersed fibers provide for a large variety of processing conditions in the manufacture of articles from such starch-based compositions (e.g., greater variations in the use of water, the amount of water that must be removed to yield a form stable article, and wall thickness). Articles formed thereby have greatly improved mechanical properties as a result of the reinforcing effect of the uniformly dispersed fibers. The fibers preferably have an average length of at least about 2 mm and an aspect ratio of at least about 25:1. Other admixtures may be added to the starch-based compositions upon dispersing the fibers, such as ungelatinized starch, rheology-modifying agents, mold-release agents, inorganic fillers, hydraulically settable binders, plasticizers, integral coating or sealing materials, and dispersants.

Claims

1. A method for dispersing fibers within a fibrous composition comprising the steps of:

(a) combining together water, fibers, and a thickening agent such that the thickening agent and water interact together to form a fluid fraction that is characterized by a yield stress and viscosity that enables the fibers to be substantially uniformly dispersed throughout the fibrous composition as the fibers and fluid fraction are mixed together, the fibers having an average length greater than about 2 mm and an average aspect ratio greater than about 25;

1; and

(b) mixing together the combined thickening agent, water, and fibers in order to substantially uniformly disperse the fibers throughout the fibrous composition.

2. A method as defined in claim 1, wherein the thickening agent comprises a starch-based thickener.

3. A method as defined in claim 2, wherein the starch-based thickener includes a pregelatinized starch.

4. A method as defined in claim 2, wherein the starch-based thickener includes a modified starch.

5. A method as defined in claim 2, wherein the starch-based thickener includes an unmodified starch having a gelation temperature and wherein the fluid fraction is formed by interacting the unmodified starch with water heated to at least the gelation temperature of the unmodified starch.

6. A method as defined in claim 1, wherein the thickening agent is included in an amount in a range from about 5% to about 40% by weight of the fluid fraction.

7. A method as defined in claim 1, wherein the thickening agent is included in an amount in a range from about 8% to about 25% by weight of the fluid fraction.

8. A method as defined in claim 1, wherein the thickening agent is included in an amount in a range from about 10% to about 15% by weight of the fluid fraction.

9. A method as defined in claim 1, wherein step (a) comprises the steps of:

(i) placing together at least a portion of the water and fibers to form a fibrous slurry;

(ii) adding the thickening agent to the fibrous slurry; and

(iii) causing the thickening agent and water to interact together to form the fluid fraction.

10. A method as defined in claim 1, wherein step (a) comprises the steps of:

(i) placing together at least a portion of the water and thickening agent;

(ii) causing the thickening agent and water to interact together to form the fluid fraction; and

(iii) adding the fibers to the fluid fraction.

11. A method as defined in claim 1, wherein step (a) comprises the steps of:

(i) placing together the fibers and thickening agent;

(ii) blending water with the fibers and thickening agent such that the water and thickening agent interact together to form the fluid fraction.

12. A method as defined in claim 1, wherein step (a) comprises the steps of:

(i) placing together the water, thickening agent, and fibers; and

(ii) causing the thickening agent and water to interact together to form the fluid fraction.

13. A method as defined in claim 1, wherein the yield stress of the fluid fraction is greater than about 10 Pa.

14. A method as defined in claim 1, wherein the yield stress of the fluid fraction is in a range from about 20 Pa to about 2000 Pa.

15. A method as defined in claim 1, wherein the yield stress of the fluid fraction is in a range from about 50 Pa to about 1000 Pa.

16. A method as defined in claim 1, wherein the yield stress of the fluid fraction is in a range from about 100 Pa to about 500 Pa.

17. A method as defined in claim 1, wherein the apparent viscosity of the fluid fraction measured at a shear rate of 5 s^-1 is greater that about 3 Pa.s.

18. A method as defined in claim 1, wherein the apparent viscosity of the fluid fraction measured at a shear rate of 5 s^-1 is in a range from about 5 Pa.s to about 1000 Pa.s.

19. A method as defined in claim 1, wherein the apparent viscosity of the fluid fraction measured at a shear rate of 5 s^-1 is in a range from about 10 Pa.s to about 500 Pa.s.

20. A method as defined in claim 1, wherein the apparent viscosity of the fluid fraction measured at a shear rate of 5 s^-1 is in a range from about 30 Pa.s to about 200 Pa.s.

21. A method as defined in claim 1, wherein the water, thickening agent, and fibers are mixed together for a period of time in a range from about 10 minutes to about 2 hours.

22. A method as defined in claim 1, wherein the water, thickening agent, and fibers are mixed using a kneader mixer.

23. A method as defined in claim 1, wherein the water, thickening agent, and fibers are mixed using a high shear mixer.

24. A method as defined in claim 1, wherein the water, thickening agent, and fibers are mixed using a twin auger extruder.

25. A method as defined in claim 1, wherein the fluid fraction is characterized as having an approximate Binghamian flow.

26. A method as defined in claim 1, wherein the fibers have an average length in a range from about 2 mm to about 25 mm.

27. A method as defined in claim 1, wherein the fibers have an average aspect ratio greater than about 100:

1.

28. A method as defined in claim 1, wherein the fibers have an average aspect ratio greater than about 1000:

1.

29. A method as defined in claim 1, wherein the fibers comprise natural cellulosic fibers.

30. A method as defined in claim 1, wherein the fibers comprise synthetic organic fibers.

31. A method as defined in claim 1, wherein the fibers comprise inorganic fibers.

32. A method as defined in claim 1, wherein the substantially uniformly dispersed fibers have a concentration in a range from about 1% to about 40% by weight of the fibrous mixture.

33. A method as defined in claim 1, wherein the fibers are combined into the fibrous mixture in an amount in a range from about 2% to about 80% by weight of solids in the fibrous mixture.

34. A method as defined in claim 1, further including adding a volatile, water-miscible organic solvent to the fibrous composition.

35. A method as defined in claim 1, further including adding a mineral filler to the fibrous composition.

36. A method as defined in claim 1, further including adding a solid organic filler to the fibrous composition.

37. A method as defined in claim 1, further including adding a dispersant to the fibrous composition.

38. A method as defined in claim 1, further including adding a humectant to the fibrous composition.

39. A method as defined in claim 1, further including adding a mold release agent to the fibrous composition.

40. A method as defined in claim 1, further including adding an enzyme to the fibrous composition.

41. A method as defined in claim 1, further including adding an unmodified starch-based binder to the fibrous composition.

42. A method as defined in claim 1, further including adding an integral sealing material to the fibrous composition.

43. A method for dispersing fibers within a starch-based composition comprising the steps of:

(a) combining water and fibers having an average length greater than about 2 mm and an average aspect ratio greater than about 25;

1 to form a fibrous slurry;

(b) blending a starch-based thickening agent with the fibrous slurry such that the water and thickening agent interact together to form a fluid fraction that is characterized by a yield stress and viscosity that enable the fibers to be substantially uniformly dispersed throughout the starch-based composition as the fibers and fluid fraction are mixed together; and

(c) mixing together the fibers and fluid fraction in order to substantially uniformly disperse the fibers throughout the starch-based composition.

44. A method for dispersing fibers within a starch-based composition comprising the steps of:

(a) combining water and a starch-based thickening agent such that they interact together to form a fluid fraction that is characterized by a yield stress and viscosity that enables fibers to be substantially uniformly dispersed throughout the starch-based composition as the fibers and fluid fraction are mixed together; and

(b) mixing fibers into the fluid fraction in order to substantially uniformly disperse the fibers throughout the starch-based composition without substantial further addition of heat to the starch-based composition, the fibers having an average length greater than about 2 mm and an average aspect ratio greater than about 25;

1.

45. A method for dispersing fibers within a starch-based composition comprising the steps of:

(a) combining water, fibers, and a starch-based thickening agent to form a fibrous slurry having a concentration of fibers in a range from about 1% to about 40% by weight of the fibrous slurry, the fibers having an average length greater than about 2 mm and an average aspect ratio greater than about 25;

1;

(b) causing the starch-based thickening agent and water to interact together to form a fluid fraction that is characterized by a yield stress and viscosity that enables the fibers to be substantially uniformly dispersed throughout the starch-based composition as the fibers and fluid fraction are mixed together; and

(c) mixing together the fibers and fluid fraction in order to substantially uniformly disperse the fibers throughout the starch-based composition without substantial further addition of heat to the starch-based composition.

46. A method for dispersing fibers within a starch-based composition comprising the steps of:

(a) combining together water, fibers having an average length of at least about 2 mm and an average aspect ratio of at least about 25;

1 and a starch-based thickening agent such that the thickening agent and water interact together to form a fluid fraction having a yield stress greater than about 10 Pa and an apparent viscosity measured at a shear rate of 5 s^-1 greater that about 3 Pa.s; and

(b) mixing together the combined starch-based thickening agent, water, and fibers in order to substantially uniformly disperse the fibers throughout the starch-based composition, the substantially uniformly dispersed fibers having a concentration in a range from about 1% to about 40% by weight of the starch-based composition.

47. A method for dispersing fibers within a starch-based composition comprising the steps of:

(a) combining together water, fibers having an average length of at least about 2 mm and an aspect ratio of at least about 25;

1, and a starch-based thickening agent such that the thickening agent and water interact together to form a fluid fraction that is characterized by a yield stress and viscosity that enables the fibers to be substantially uniformly dispersed throughout the starch-based composition as the fibers and fluid fraction are mixed together; and

(b) mixing together the combined starch-based thickening agent, water, and fibers in order to substantially uniformly disperse the fibers throughout the starch-based composition, the fibers having a concentration in a range from about 1% to about 40% by weight of the starch-based composition.

48. A method for dispersing fibers within a starch-based composition comprising the steps of

(a) combining together water, fibers having an average of at least about 2 mm and an aspect ratio of at least about 25:

1, and an ungelatinized starch-based thickening agent to form a fibrous slurry;

(b) heating the fibrous slurry in order to gelatinize the ungelatinized starch-based thickening agent and thereby form a fluid fraction that is characterized by a yield stress and viscosity that enables the fibers to be substantially uniformly dispersed throughout the cellulose-based composition as the fibers and fluid fraction are mixed together, the heating step being performed without any substantial evaporation of water from the fibrous slurry; and

(c) mixing together the combined cellulose-based thickening agent, water, and fibers in order to substantially uniformly disperse the fibers throughout the cellulose-based composition, the fibers having a concentration in a range from about 1% to about 40% by weight of the starch-based composition.

49. A fibrous composition having substantially uniformly dispersed fibers comprising water, a thickening agent, and fibers having an average length of at least about 2 mm and an average aspect ratio of at least about 25:

1, the water and thickening agent together comprising a fluid fraction that is characterized by a yield stress and viscosity that enable the fibers to be substantially uniformly dispersed throughout the fibrous composition as the fibers and fluid fraction are mixed together.

50. A starch-based composition having substantially uniformly dispersed fibers comprising water, a starch-based thickening agent, and fibers having an average length of at least about 2 mm, an average aspect ratio of at least about 25:

1 and a concentration in a range from about 1% to about 40% by weight of the starch-based composition, the water and starch-based thickening agent together comprising a fluid fraction having a yield stress greater than about 10 Pa and an apparent viscosity measured at a shear rate of 5 s^-1 greater that about 3 Pa.s.

51. A starch-based composition having substantially uniformly dispersed fibers comprising water, a starch-based thickening agent, and fibers having an average length of at least about 2 mm and an average aspect ratio of at least about 25:

1, the water and starch-based thickening agent together comprising a fluid fraction that is characterized by a yield stress and viscosity that enable the fibers to be substantially uniformly dispersed throughout the starch-based composition as the fibers and fluid fraction are mixed together without any substantial evaporation of the water from the starch-based composition.

52. A fibrous composition having substantially uniformly dispersed fibers formed by the process comprising the steps of:

(a) combining together water, fibers, and a thickening agent such that the thickening agent and water interact together to form a fluid fraction that is characterized by a yield stress and viscosity that enables the fibers to be substantially uniformly dispersed throughout the fibrous composition as the fibers and fluid fraction are mixed together, the fibers having an average length greater than about 2 mm and an average aspect ratio greater than about 25;

1; and

(b) mixing together the combined thickening agent, water and fibers in order to substantially uniformly disperse the fibers throughout the fibrous composition.

53. A starch-based composition having substantially uniformly dispersed fibers formed by the process comprising the steps of:

(a) combining together water, fibers, and a starch-based thickening agent such that the thickening agent and water interact together to form a fluid fraction that is characterized by a yield stress and viscosity that enables the fibers to be substantially uniformly dispersed throughout the starch-based composition as the fibers and fluid fraction are mixed together, the fibers having an average length greater than about 2 mm and an average aspect ratio greater than about 25;

1; and

(b) mixing together the combined starch-based thickening agent, water, and fibers in order to substantially uniformly disperse the fibers throughout the starch-based composition, the fibers having a concentration in a range from about 1% to about 40% by weight of the starch-based composition.

54. A starch-based composition having substantially uniformly dispersed fibers formed by the process comprising the steps of:

(a) combining together water, fibers having an average of at least about 2 mm and an aspect ratio of at least about 25;

1, and an ungelatinized starch-based thickening agent to form a fibrous slurry;

(b) heating the fibrous slurry in order to gelatinize the ungelatinized starch-based thickening agent and thereby form a fluid fraction that is characterized by a yield stress and viscosity that enables the fibers to be substantially uniformly dispersed throughout the cellulose-based composition as the fibers and fluid fraction are mixed together, the heating step being performed without any substantial evaporation of water from the fibrous slurry; and

(c) mixing together the combined cellulose-based thickening agent, water, and fibers in order to substantially uniformly disperse the fibers throughout the cellulose-based composition, the fibers having a concentration in a range from about 1% to about 40% by weight of the starch-based composition.