What are High Oxygen Barrier Films?

What are High Oxygen Barrier Films?
Using plastic is for now the best option to cover your silage and get the best return on investment. But, do you know what kinds of plastic there are and which ones will help you get the most out of your homegrown forage? In this articles, we will explore the differences and why Silostop is so special.
Polyethylene (PE), the most widely consumed polymer in the packaging industry, is a highly efficient material compared to other key elements and polymers. The excellent characteristics of PEs, namely: good flow, good thermal stability, broad density range and excellent chemical resistance, make it a material with multiple applications.

Transparent and flexible gas barrier films are key components in food packaging. In most cases, food processors, are mainly served by low density PE (LDPE) and linear low-density PE (LLDPE). The main problem of polyethylene is its high oxygen permeability. Having a barrier capacity is crucial for plastics films used in the food packaging which favours the preservation of nutritional and organoleptic product qualities, this model is exactly the same for the silage making process... For this purpose, it is necessary to prevent crop losses from the penetration of external gas (oxygen) through plastics.

Various methods are used to stop the transmission of oxygen in the food sector but for Silage Films the key has been a thin layer of EHOV encased in layers of PE and LDPE film.

This “layer by layer” technology was used to create transparent, thin and high barrier polyethylene films to use in food packaging. These films were made by inserting successive layers of polyacrylamide and montmorillonite (Cloisite Na⁺, non-organic modification) grown onto a low density polyethylene (LDPE) film substrate submitted to corona treatment. Excellent oxygen permeability results were reached with only 9 bilayers, with a reduction of 99.92%, compared to the pure polyethylene. This allowed the oxygen barrier film to change from poor to high (3.66 cm³/m²·day), with a total thickness of 45 microns, due to the structure formed over the film to create a tortuous path for oxygen molecules. Optical properties were analysed, showing a ≥92% transparency in all samples. Thermal stability of polyethylene was slightly improved and this was attributed to nanoclays presence forming an insulating layer. The result of this research is a thin structured film which is a good candidate for common barrier films replacement in food packaging thanks to its high oxygen barrier capacity, optical transparency, microwaveability and recyclability.

Take this to farm level and you get a strong, flexible 45 micron film that will cling to the surface of the crop, eliminating waste due to trapped oxygen as well as the prevention of further oxygen entering the crop through the plastic sheet. These films fall into the High Oxygen Barrier film category (HOB).

So, if these films are HOB what are the rest – Low and Medium Oxygen Barrier films.

The traditional 120 micron black PE film will have an Oxygen Transmission Rate (OTR) of 300cm3/m2 which would put it in the Medium bracket and the 40 micron clear Cling Films that have become very popular over the last 10 years, and will certainly help reduce surface waste actually have an OTR of 900-1000cm3/m2 so they are actually Low Oxygen Barrier films.