From Introduction to Plastics Recycling, Second edition
6.10 Conclusion
An overview of the processes discussed in this chapter is given in Table 6.1. Whilst primary mechanical recycling will continue to be common practice amongst plastics processors, secondary recycling is subject to both practical and economic limits for use. Success depends primarily upon the economics of sorting to obtain single polymer materials, and knowledge of material provenance and degradation history. Processes adapted from conventional machinery to take more highly contaminated feedstock exist, however they are limited in application to wood replacement type profiles and panels and cannot overcome the inherent limitations in the make-up of their feedstock. Even these processes also generally require feedstock to have undergone some preliminary sorting. The next chapter will look at ways to upgrade recyclate materials in order to improve upon their properties for mechanical recycling applications.
| Process | Complexity of parts | Forming action | Mould | Plastic types | Tolerance to contaminants |
|---|---|---|---|---|---|
| Extrusion | Fairly simple profiles | Extrusion | None | Single | Low |
| Injection moulding | Complex | Injection | Closed | Single | Low |
| Co-injection moulding | Complex | Injection | Closed | Single layers | Low |
| Compression moulding | Simple | Compression | Closed | Single | Medium |
| Extrusion blow moulding | Complex | Inflation | Closed | Single | Very low |
| Multi-layer extrusion blow moulding | Complex | Inflation | Closed | Single layers | Very low |
| Injection blow moulding | Simple | Inflation | Closed |
Products & Services
Topics of Interest
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