Biodegradable stretch films for silage bales: basically possible

Films made of Ecoflex copolyester (BASF AG) offer good mechanical properties as well as a sufficiently low oxygen permeability in order to satisfy the requirements of stretch films used for silage bales. Films which are stabilised by carbon black also fulfil practically all these criteria. These two types of film were used to wrap silage bales which were then stored beneath a roof or outside, either on the meadow or on palettes. Degradation of the films was observed as early as after 20 to 80 days, depending on the manner of storage. On the one hand, the films were attacked from inside the bales, on the other, on the contact surface between the soil and the film. In order to use copolyester films for silage bales, degradation should be significantly slower. This can be achieved by adding an adhesive layer limiting degradation or by chemically modifying the films’ material.