Plastic Recycling: Turn Waste Plastics into Valuable Resources

Preface

The vast majority of thermoplastics can be recycled and regenerated. Production trimmings, discarded packaging and foam buffer scraps from the market can all be processed into recycled pellets by complete recycling equipment. It acts as a core sector of environmental protection industry and a key supporting facility for manufacturers to cut costs and improve efficiency. The PS foam recycling machine independently developed by Keli Machinery supports the regeneration and processing of various foam plastic scraps.

Current Status of Physical Recycling

Mechanical physical recycling stands as the mainstream method for waste plastic resource recovery. It realizes plastic reprocessing through physical procedures such as crushing, drying and melt granulation without generating extra pollutants, featuring simple techniques and low investment costs. For instance, waste PET bottles can be turned into polyester fiber for textiles after being treated by complete recycling equipment, which realizes secondary resource utilization.

From a global perspective, countries have rolled out regulations on plastic restriction and circular economy one after another, driving the large-scale development of plastic physical recycling industry. The market demand for recycled plastics keeps rising, and integrated fully-automatic recycling production lines have gradually become mainstream configurations in the industry.

Processes & Specific Technologies of Physical Recycling

The core logic of physical recycling is to reshape waste plastics via mechanical equipment, covering complete procedures including crushing, sorting, melting and modification. Integrated recycling production lines can realize full-automatic processing. After crushing, dewatering, high-temperature extrusion and water-cooled pelletizing, waste materials are made into standard recycled pellets. These recycled materials can be re-input into the PS foam sheet production line to manufacture brand-new buffer packaging boards, greatly cutting the consumption of virgin resin.

Three mainstream physical recycling technologies are listed as follows:

（1）Melt Extrusion Method: Waste plastics are heated and melted for extrusion molding. Though the material performance slightly declines after processing, the produced polyester fiber is still widely applied in garments and home textiles.

（2）Dissolution & Reprecipitation Method: Special solvents are adopted to dissolve plastics followed by precipitation and purification. This method maximally retains the original molecular structure of plastics and produces high-purity recycled materials for high-end product manufacturing.

（3）Crushing & Reuse of Thermosetting Plastics: Thermosetting plastics cannot be melted again, so they are generally crushed into fillers and blended with other plastics to make composite materials for diversified new products.

Relevant industrial research indicates that when recycled resin is mixed with virgin resin with virgin material accounting for around 90%, the performance of blends is almost identical to pure new products. Meanwhile, physical blending with modifiers can further boost the mechanical properties of recycled plastics and greatly raise their economic value.