Low-density polyethylene (LDPE) and Linear low density polyethylene (LLDPE) are two valuable polymers in the agricultural industry. The high demand for these materials has pushed the need for recycling to a standardized quality so that the recyclates may be used in place of raw material. One common problem from recycling them however is contamination. When ready to be recycled, the film is usually heavily soiled and it can be challenging to feed the material into the recycling system.
How are contaminated agricultural films such as LDPE and LLDPE recycled then?
- The plastic is first cut down to 2-4” shreds and is sent through a process of washing, grinding, and drying to eliminate the first round of contamination.
- The shreds are then processed through a multifunctional cutter/compactor system to reduce moisture before extrusion. This is a key process step and further dries the material prior to entering the hot melt stage. Removing moisture prior to extrusion maintains material properties by significantly reducing degradation.
- The material is then feed into a single-screw extruder, consistency and high throughput are key performance criteria for the feeding process. During this stage, a melt filter eliminates the majority of the remaining contaminants.
- After melt filtration the material is further homogenized and degassed one last time, and is then sent to the discharge zone where it is made into pellets that can be reused.
With the right recycling process and machinery, recycling of agricultural film is not only possible but is profitable as well! High quality pellets are possible that meet the specifications to be re-introduced into the original blown film process. Where EREMA can help is with assessing the specific application – there are many variations of agricultural film and each requires adjustments to the process. We can help customers to assess their specific requirements by running tests in our test center in Massachusetts or Austria.
