PE Film Pelletizing Machine

Applications: Types of Plastic Films, Recycling, and Uses of Recycled Pellets

Recyclable Types:

• Polyethylene (PE) Films:
  This includes LDPE (Low-Density Polyethylene) and LLDPE (Linear Low-Density PE) films, such as stretch wrap, pallet wrap, agricultural cover film, greenhouse film, silage wrap, construction plastic sheeting, shopping bags, grocery bags, and trash bags. HDPE (High-Density Polyethylene) film is also common—though HDPE is often used in semi-rigid applications, HDPE films are found in thicker grocery bags or produce bags.

• Polypropylene (PP) Films:
  Key examples include PP woven bags and woven polypropylene sacks (often broadly considered “films” since they are flexible sheets, although made from woven tapes). Additionally, BOPP (Biaxially Oriented Polypropylene) film—widely used in snack packaging, labels, and tapes—is a very common and recyclable PP film.

• Multilayer and Co-extruded Films:
  Many packaging films are multilayered (e.g., a layer of PP and a layer of PE, or other polymers) or contain barrier layers (like EVOH, PA nylon, or metallized layers). These materials are more challenging but can still be pelletized if separated from non-polyolefin materials. For example, multilayer film waste from packaging production can be pelletized into mixed-polymer pellets for use in products like plastic lumber or some injection molded items. If all layers are thermoplastic and melt-compatible, they can be processed by the machine. However, non-melting contaminants (e.g., aluminum foil or paper laminates) must be removed during melt filtration. Recyclers often process "mixed film" bales (possibly including PE, PP, and some metallized films)—the output pellets are a mix, generally used for lower-end applications but still preferable to waste.

• Specialty Films:
  Polyester (PET) and PVC films are also film types but require different handling. PET films (such as overhead transparencies, X-ray film base, or some packaging films) have high melting points and are typically pelletized using different machinery (often vacuum twin-screw extruders due to PET’s hydrolysis issues). PVC films (like PVC-based cling film or vinyl banners) are generally not processed on the same lines as PE/PP because PVC releases HCl gas upon melting, which corrodes equipment and requires special ventilation and temperature control. Some machines can also process PS (Polystyrene) or ABS film/sheet waste, though these are less common in film form. EVA films (from solar panel encapsulants or packaging) and polyamide (nylon) films may require dedicated extruders due to their material properties.

Sources of Input Materials:

• Industrial Scrap:
  Includes edge trim from film extrusion lines, defective film rolls, leftover cuttings from bag making, or scrap from packaging production. These are typically clean and can often be pelletized without washing (directly in cutter-compactor-extruder systems).

• Post-Consumer Waste:
  Includes used plastic bags, packaging film collected from retailers or consumers, and agricultural film recovered from fields. These generally require washing to remove contaminants like dirt, labels, or food residue. Post-consumer films are often dirtier and have more printing (like printed packaging).

• Post-Industrial Waste:
  Includes films from agricultural cooperatives (e.g., greenhouse covers being replaced), or pallet wraps collected in warehouses. These are usually less contaminated than post-consumer waste but may still have dirt or sand, especially in agricultural applications.

• PP Woven Jumbo Bags:
  Typically contain woven fabric and contaminants like sand or product residues. These can be recycled by first washing and then pelletizing with a two-stage extruder to obtain clean PP pellets.

It's important to note that the quality of the output pellets depends on the input and the process. Clean, homogeneous materials can produce high-quality pellets—often nearly as good as virgin resin.

Mixed or heavily contaminated materials result in darker-colored pellets or those with some impurities, limiting their use to less demanding applications (not high-end film, but possibly trash bags or injection parts).

For export or high-end reuse, additional steps (such as fine filtration down to 80-micron screens and the addition of stabilizers) can allow the recycled pellets to be used in more demanding applications.

Chinese pelletizer manufacturer Boxin often recommends using a two-stage extruder and fine filtration for critical products or international markets to ensure the pellets meet higher quality standards (no gels, no odor).

Uses of Recycled Pellets:

So, once you’ve produced pellets from waste film—what can you do with them? The good news is that recycled PE or PP pellets are highly versatile and can be reintroduced into a wide range of plastic production applications. Common uses include:

• Film Blowing & Bag Production:
  High-quality recycled pellets—especially those from clean industrial film waste—can be used to produce new films. For instance, recycled LLDPE pellets can be blended with virgin LLDPE to make trash bags, agricultural film, or shopping bags. Many film producers include 10–30% recycled content in non-food packaging films. Some even make 100% recycled trash bags or construction sheeting from post-consumer film pellets. The key is that the pellets must be clean and perform close to virgin specs. HDPE pellets recycled from film can also be used for blowing new thin bags, though HDPE film is typically used in thicker applications like shopping bags or mixed with LDPE.

• Injection Molding:
  Pellets recycled from film (usually PE or PP) can be fed into injection molding machines to make a variety of products. Common examples include plastic crates, buckets, flower pots, pallets, and other molded items—recycled material helps reduce costs. For instance, PP pellets from woven bag recycling can be used to mold paint buckets or battery cases. PP from woven bags is often used in injection molding due to its stiffness. PE recycled pellets can be used in items like compost bins, park benches (especially when blended with wood fibers), or other non-structural parts. Manufacturers often note that their line’s pellets can be directly fed into injection or film-blowing machines for new products.

• Pipe and Profile Extrusion:
  Some recycled pellets—especially HDPE or PP—are used to extrude pipes (like irrigation or corrugated drainage pipes) or profiles such as plastic lumber, fence posts, etc. For example, LDPE/LLDPE recyclates aren't suitable for load-bearing applications but can be part of composite lumber or small pipe production. HDPE from film recycling can be used for light-duty piping or conduit (usually not pressure pipes). During pelletizing, you can blend different streams, like LDPE film pellets with some HDPE, to get a stiffer output for specific profile extrusion. The pellet form and consistent melt quality achieved by the pelletizer make feeding these extruders seamless.

• Blow Molding:
  In some cases, recycled pellets can be used for blow-molded products (hollow items like bottles or drums). However, film-grade PE is typically low molecular weight and not suitable for making strong blow-molded products like thick bottles (which require high molecular weight HDPE). Still, thinner blow-molded items or inner layers of multilayer bottles may include recycled film pellets. This is less common than film or injection applications but is possible.

• Fibers and Textiles:
  Interestingly, PP or PE recovered from film can be turned into fibers or nonwovens. For example, some PP woven bag recyclers pelletize the material and then use the pellets to produce PP staple fibers or spunbond nonwovens (used in carpets, geotextiles, furniture linings, etc.). The quality must be high (free from contaminants that could clog spinnerets), but it has been done. Recycled PE pellets are even used to make coarse monofilaments that can be woven into construction tarps or mesh products.

To ensure pellets meet application requirements, additives can be introduced during the pelletizing process. For instance, if the recycled film is slightly degraded, stabilizers or antioxidants can be added to improve the long-term stability of the pellets. Color masterbatch can also be added to give recycled pellets a uniform color (typically black or gray to mask inconsistencies). Some pelletizer systems include a side feeder to add such additives inline.