Thermoplastic starch-containing materials

摘要

Homogenous, undried, melt-extruded thermoplastic composition comprises 30-60 wt.% of dry substance (a) of native or chemically modified starch, at most 11 wt.% of dry substance (b) of at least one further biopolymer, which includes carrageenan, other polysaccharides or protein, at least one softener (c) and maximum 20 wt.% of added water (d). Independent claims are included for: (1) a method for preparing the thermoplastic composition, comprising (i) mixing (a), (b), (c) and (d), (ii) adding the obtained mixture in an extruder and melted in the extruder at increased pressure of 10-300 atmosphere, increased temperature of at least 40[deg] C above room temperature and preferably product temperature of 60-150[deg] C, increased shearing of 0.15-0.67 kilowatt-hour (kWh)/kg and short dwell time between the first contact of all components after adding in the extruder and the outlet of the melted homogenous mixture from the extruder of maximum 5 (preferably 2) minutes, where the total water content is less than 20 wt.% of the total weight to obtain the homogenous thermoplastic compound; (2) a molded body, preferably soft capsule, comprising a cover made of the homogenous, thermoplastic composition; and (3) a method for preparing the molded body, comprising preparing the homogenous, thermoplastic composition by the above method and forming a molded body in a molding process (preferably rotary die-process).