Every recycled-content claim a buyer receives rests on a decision made long before the resin reached the supplier: which route turned the waste into feedstock. The chemical recycling vs mechanical recycling question is really a question about what the waste stream looks like and what the output must achieve. Mechanical recycling works on clean, sorted, single-polymer material and keeps the polymer chain intact. Chemical recycling breaks the chain back down to monomers or hydrocarbons, accepting dirtier input for a cleaner output. Both routes are scaling under EU recycled-content rules, and a buyer who cannot tell them apart cannot evaluate a quotation.
What Mechanical Recycling Delivers
Mechanical recycling is the mature route: collection, sorting, washing, grinding, melt filtration and re-pelletising. Because the polymer is not chemically altered, the process keeps a high share of input as usable plastic, commonly cited in the 70-90% range, at the lowest cost and the lowest energy demand of any route. The trade-off is feedstock quality: mixed resins, strong colours and contamination quickly degrade the output, and each melt cycle shortens the chains slightly, so mechanical recyclate survives a limited number of loops before properties fall below demanding specifications. The exceptions are well-controlled streams: food-grade rPET from bottle-to-bottle super-clean lines and, more rarely, food-grade rHDPE, where decontamination steps and authorised processes make direct food contact possible.
What Chemical Recycling Delivers
Chemical recycling operates at the molecular level and comes in three broad families. Depolymerisation unzips specific polymers back to monomers: PET through glycolysis or methanolysis, polyamide 6 back to caprolactam, polyurethane back to polyols. Pyrolysis and gasification crack mixed or multi-layer waste into pyrolysis oil, naphtha or syngas for refinery use. Dissolution selectively dissolves polymers such as polystyrene, separating them from additives and other materials. The output can be virgin-equivalent and colourless regardless of input colour, but end-to-end plastic-to-plastic yields are lower, commonly cited around 40-70%, and energy demand is higher.
Chemical Recycling vs Mechanical Recycling: The Core Differences
| Dimension | Mechanical recycling | Chemical recycling |
|---|---|---|
| Feedstock | Clean, sorted, mono-material | Mixed, coloured, multi-layer |
| Output | Recycled pellets with some property loss | Monomers, oil or virgin-equivalent resin |
| Plastic-to-plastic yield | High, roughly 70-90% | Lower, roughly 40-70% |
| Food-grade potential | Established for rPET, limited for rPE and rPP | Technically possible, commercially young |
| Relative cost | Low | High |
| Energy and carbon | Low, best-in-class savings | Higher, results vary by process |
| Maturity | Commercial at scale | Early commercial to demonstration |
Which Polymers Suit Which Route
- Clear PET bottles - mechanical super-clean lines deliver food-grade rPET at scale.
- Coloured PET trays and polyester textiles - depolymerisation recovers monomers that mechanical routes cannot reuse.
- Multi-layer flexible packaging - pyrolysis handles what sorting cannot separate.
- Polystyrene streams - dissolution offers high material yield with purification.
- Mixed sorting residues - chemical routes divert material that would otherwise go to incineration.
The Compliance Angle for Buyers
Regulation (EU) 2025/40 sets minimum post-consumer recycled content for plastic packaging from 2030, including 30% for single-use PET beverage bottles and contact-sensitive PET packaging, 10% for other contact-sensitive packaging and 35% for other plastic packaging, calculated per plant per year. Food-contact packaging is exempt where recycled content would break compliance with Regulation (EC) 1935/2004, so the safe route matters as much as the number. Mechanically recycled content is credited physically, while chemical recyclate entering crackers is usually credited through mass-balance accounting such as ISCC PLUS, a distinction that changes what a supplier can document.
What to Ask Before Specifying Recycled Content
Ask which route produced the recyclate, request the recycled-content percentage and the accounting method behind it, and require a declaration of compliance that names the process. For food-contact applications, ask specifically whether the recyclate comes from an authorised recycling process. Our PCR grade guide, recycled content targets and rPET market outlook go deeper on the sourcing side, and the plastic materials directory lists resin suppliers by specialism.
