What slows down recycling: common plastic contaminants explained

 
Plastic recycling becomes slower, more expensive, and less reliable when contamination enters the stream. Knowing which contaminants appear most often is essential for boosting efficiency and improving the quality of the recycled material.
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Plastic recycling is essential for sustainability, but contamination can create serious challenges. Even small amounts of foreign material can slow down processing, increase maintenance needs, and reduce the quality of recycled output. Understanding these common types of contaminants is key to improving efficiency and output:

 
Food residues

Leftover food introduces moisture and organic matter that interfere with shredding, washing, and separation. Residues can increase microbial activity, raise cleaning requirements, and lower the consistency of the final recycled pellet.

 
Labels, adhesives, and paper

Labels, paper sleeves, inks, and adhesive layers remain bonded to packaging and are difficult to remove. They clog filters, introduce impurities during extrusion, and reduce material purity, leading to more frequent equipment downtime.

 
Oils and greases

Industrial lubricants, cooking oils, and similar substances prevent proper melting and bonding of plastic during reprocessing. They create surface defects, slow production, and require additional degreasing steps to maintain stable output quality.

 
Mixed or multilayer plastics

Items made from several polymers or laminated structures resist separation during sorting and washing. Their incompatible material layers reduce melt homogeneity and typically result in lower-grade recycled material unless specialized processing is used.

 
Dirt, sand, and fine particulates

Plastics collected from outdoor, agricultural, or construction environments often carry soil and abrasive particles. These contaminants accelerate machinery wear, increase filtration loads, and reduce the mechanical strength of recycled output.

Identifying and removing these contaminants early in the recycling process improves efficiency, protects equipment, and ensures stable, high-quality recycled material.
 
For additional guidance on managing contamination in recycled plastics, email Alessandro Sartori at alessandro.sartori@breakmachinery.com