Ensuring Stored Silage Remains Nutritious
In cold countries, maize and grass are grown during the summer, but need to be used in feed livestock throughout the year. A plastic film is used to store the silage and maintain its nutritional value. Three main types of film are used: silo bags (150-300 micron thickness), silage film (150-200 micron thickness) and stretch (20-30 micron thickness), which all perform similarly.
Silage films contain a high percentage of recycled material. They are usually produced with a 3 to 5-layer blown extruder, but some more advanced films are produced on a 7-layer extruder. New norms are being introduced to the market to deal with the requirement that the film act as a barrier to oxygen. The more advanced silage films that have an oxygen barrier are produced with a 5 and 7-layer extruder .
Silage film is produced with either an EVOH or PA layer on a 5-layer extruder – since neither polymer is compatible with the PE in the adjacent layers, a tie layer is needed to allow for adherence of the PE and barrier layers. We have developed a new barrier MB that is compatible with PE, enabling production of a barrier film on a 3-layer extruder.