Abstract: The present invention relates to a single-stage process for the production of starch blends in a twin-screw extruder or two twin-screw extruders arranged in series, where i) the starch, together with a plasticizer, passes through a wetting section of length 8D to 30D in an extruder or in a wetting section of length 8D to 80D if two extruders are used at temperatures below the gelatinization temperature of the starch, with mixing, where D is defined as the screw diameter of the screw cylinder and the wetting section is defined as starting at that point on the extruder screw at which the starch and the entire or partial quantity of plasticizer encounter one another and ending at that point in the extruder at which the starch is gelatinized and is digested to give thermoplastic starch; ii) in a plastifying section of length 10D to 50D the extruder temperature is adjusted stepwise to above 130° C.

Abstract: The invention relates to a biodegradable three-layer polyester film of 8 to 20 ?m in thickness having a layer construction NB/C or preferably A/B/A, wherein the two outer layers (A) or (A, C) are composed of: Ai) 55% to 99.99% by weight based on the polyester mixture of the outer layers of a polyester selected from the group consisting of: polybutylene sebacate-co-terephthalate, polybutylene sebacate-co-adipate-co-terephthalate, polybutylene sebacate-co-succinate-co-terephthalate or mixtures thereof or a mixture of polybutylene sebacate-co-terephthalate and polybutylene adipate-co-terephthalate; Aii) 0.01% to 5% by weight based on the polyester mixture of the outer layers of at least one additive selected from the group consisting of: a wax, a plasticizer, a nucleating agent, antifogging agents, fillers and an antiblocking agent; and Aiii) 0% to 44.