Starch derived shaped articles
First Claim
1. A method of manufacturing a starch derived shaped article comprising the steps of:
- (1) preparing a hot melt by heating a composition comprising (a) a high amylosic material, or a derivative thereof, said derivative being selected from the group consisting of amylosic ethers, amylosic esters and combinations thereof and (b) water, the water being present in an amount of less then 24% by weight, at an elevated temperature and pressure below the temperature and pressure at which the material or derivative decomposes to provide a homogeneous melt;
(2) extruding the hot melt from an extruder to form a shaped article; and
(3) subjecting the hot melt to a subatmospheric pressure prior to issue from the extruder whereby to remove water from the shaped article.
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Accused Products
Abstract
This invention relates to a method of producing starch derived shaped articles and in particular, a method of producing films derived from high amylose starch. In the method, a hot melt is prepared by heating under pressure a composition comprising a high amylosic material, or a derivative thereof, and sufficient water to provide a homogeneous melt for subsequent extrusion as a shaped article. The hot melt is subjected to an atmospheric or subatmospheric pressure immediately prior to or during extrusion so as to remove water from the hot melt prior to the formation of the shaped article. Preferably, the high amylosic material is derived from Goodman Fielder Mills Pty. Limited maize hybrids 55/77 or 65/88. The starch derived films produced by the method are particularly suitable for use in oxygen barrier laminates and as biodegradable mulch films.
127 Citations
36 Claims
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1. A method of manufacturing a starch derived shaped article comprising the steps of:
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(1) preparing a hot melt by heating a composition comprising (a) a high amylosic material, or a derivative thereof, said derivative being selected from the group consisting of amylosic ethers, amylosic esters and combinations thereof and (b) water, the water being present in an amount of less then 24% by weight, at an elevated temperature and pressure below the temperature and pressure at which the material or derivative decomposes to provide a homogeneous melt; (2) extruding the hot melt from an extruder to form a shaped article; and (3) subjecting the hot melt to a subatmospheric pressure prior to issue from the extruder whereby to remove water from the shaped article. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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- 33. A starch based shaped film obtained by extruding in an extrusion direction a composition comprising a high amylosic material and an amount of water, said film having an average tensile strength parallel to the extrusion direction in the range of from about 1000 psi to about 1300 psi and an average elongation before failure of from about 80% to about 240%.
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35. A method of agriculture comprising the step of covering a tract of land with a biodegradable mulch film prepared by
(1) preparing a hot melt by heating a composition comprising (a) a high amylosic material, or derivative thereof, said derivative being selected from the group consisting of amylosic esters, amylosic ethers and combinations thereof and (b) water, said water being present in an amount of less than 24% by weight, at an elevated temperature and pressure below the temperature and pressure at which the material or derivative decomposes to provide a homogeneous melt; -
(2) extruding the hot melt from an extruder to form a film; and (3) subjecting the hot melt to a subatmospheric pressure prior to issue from the extruder, whereby to remove water from the film.
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36. A method of agriculture comprising the step of covering a tract of land with a biodegradable starch derived mulch film, said film having an average tensile strength parallel to the extrusion axis in the range of from about 1000 psi to about 1300 psi and an average elongation before failure of from about 80% to about 240%.
Specification