Agricultural Film Recycling
Agricultural films have become more popular as the agricultural industry continues to expand around the world.
What is agricultural film?
Agricultural films are made of polyethylene or polypropylene to protect against moisture, insects, animals, and more. Some examples of these films are:
- - Mulch Film
- - Green House Film
- - Banana Film
- - Tunnel Film
As a result, agricultural waste is excessive and difficult to recycle. Because the properties of these plastic films are difficult to handle, they are not as simple as food plastic packaging.
The following are the most prevalent components:
- High-density polyethylene (HDPE)
- Low-density polyethylene (LDPE)
- Additives - Polypropylene
- Among other things
However, when recycling, the plastic and chemical components utilized in the films are not the only elements to consider. Because contaminants such as humidity, dirt, and flora, among others, will be present in post-consumer plastic films.
How to recycle agricultural film in 3 steps
Sorting plastic waste materials
In agricultural applications, plastics must first be divided into the three most common types of polymers (LDPE, HDPE, and PP).
Crushing, washing, and drying plastic waste
It is recommended that agricultural film waste have humidity during the crushing stage since the blades of the shredders or crushers might damage the material and agglomerate the contaminants that they contain. They will next be washed on a washing line to reduce the amount of dust and sediments from the land. Normally, these washing lines require a triple washing cycle with a drying centrifuge at the end of each cycle. A hot air centrifuge is required at the end of these cycles to reduce humidity to 3 to 5%, allowing the material to be processed in a pelletizer.
Pelletizing plastic materials
Agricultural film wastes that have been crushed, washed, and dried are ready to go through the pelletizer extruder.
In its Repro-Flex Plus model, POLYSTAR has created a technology that combines cutting, extrusion, and pelletizing in one machine to handle agricultural films with low degradation. Films pass via the cutter-compactor and are fed straight to the first extruder.
The first extruder has two degassing and one filtration system (double piston). These will eliminate the contamination and moisture that the washing machine couldn't get rid of.
Between the first and second extrusions, there is a venting space that acts as a third degassing, ensuring that moisture in the materials is removed.
It then proceeds to the second extrusion, where it will pass a second filtration before being pelletized, to ensure that the material is prepared correctly and filtered for pelletization.
Finally, we have the pelletizing system, which homogenizes the material into pellets. After the pelletizing system, the recycled pellets pass through a water tank for cooling, then via a vibration tank to reduce the water in the cooling unit, and finally through a centrifugal dryer to entirely remove the water from the cooling unit for better drying.
Agricultural film recycling is difficult for the mentioned reasons above, but it can be efficiently recycled for reproduction with the correct pelletizing method.