Method for preparing biodegradable films from plant-based raw materials
AssigneeBiotec Biologische Naturverpackungen GmbH & Co. KG
InventorsJurgen Lorcks, Winfried Pommeranz, Joachim Heuer, Kurt Klenke, Harald Schmidt
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Abstract
There is provided a method for preparing biodegradable films from plant-based raw materials in the form of carbohydrates which method is continuous and carried out in one step. In the process the plant-based raw materials are modified and plastified and the films are prepared without interruption and in one step. The advantages of the invention reside in reduced shear stress of the starch molecules and thus in the improved properties of the films as well as in the cost-efficient, time-, energy- and space-saving manufacture.
Claims20
A method for preparing biodegradable films from plant-based raw materials, preferably in the form of carbohydrates by means of a screw-type extruder, wherein modification or disintegration and the plastification of the plant-based raw materials and subsequent film preparation are done continuously and in one step comprising the stages of:
- a. continuously adding measured plant-based raw materials and, if desired, solid additives through a first inlet (11) as well as, if desired, liquid additives through a second inlet (12) in a first extruder section (1) and mixing them to form a mixture,
- b. heating and kneading the mixture in a second extruder section (2),
- c. heating and reacting the mixture in a third extruder section (3) to form a melt,
- d. evacuating said melt in a vacuum apparatus (14) in a fourth extruder section (4) by extracting and allowing water to evaporate from the melt, thus causing the melt to cool down,
- e. further cooling the melt in a fifth extruder section (5),
- f. compressing the melt in a sixth extruder section (6),
- g. extruding the melt from the extruder through a die (7, 8, 9) to form a film (15, 16).
Dependencies are inferred from the claim text.