Chemical recycling breaks plastic down at molecular level to recover its basic building blocks, instead of melting it and reshaping it as mechanical recycling does. That difference makes it possible to treat dirty, mixed or degraded waste that today ends up in landfill. It does not replace mechanical recycling: it complements it and covers the fraction that mechanical recycling cannot use.
Why mechanical recycling cannot handle all plastic
In mechanical recycling, plastic is sorted, washed, shredded and melted to make pellets. It uses little energy and works well with clean, homogeneous streams, such as PET bottles.
The problem arises with everything else. There are plastics that mechanical recycling cannot process, or can only process with a loss of quality:
- Thin films and flexible packaging, which tangle in the lines and contribute little usable material.
- Multilayer packaging, which combines several polymers or plastic with aluminium and paper.
- Waste contaminated with organic residues, oils or labels that are hard to separate.
- Plastic that has already been through several recycling cycles, whose chains have shortened and lost their properties.
That fraction ends up as rejects, bound for landfill or incineration, two outlets that are becoming ever more expensive.
What chemical recycling of plastics is
Chemical recycling of plastics covers the technologies that break polymer chains using heat, pressure or reagents. The result is not pellets but smaller molecules: monomers, liquid hydrocarbons or syngas. Those molecules can go back into the chemical industry as feedstock to make new plastic or other products, or be used for energy purposes.
Because it works at molecular level, it copes better with mixed polymers and dirt, and the plastic obtained does not carry over the degradation of previous cycles. In return, it requires more energy than mechanical recycling and rigorous traceability to monetise the product.
The three main routes of chemical recycling
Each technology accepts a different type of waste and generates a different product.
Pyrolysis
Plastic waste pyrolysis heats the material in the absence of oxygen. Without oxygen there is no combustion: the long chains break into shorter fractions. Three products are obtained: a hydrocarbon oil, a gas and a carbonaceous solid residue or char.
It is the most suitable route for polyolefins (polyethylene and polypropylene) and for unsorted plastic mixtures, which make up precisely the bulk of the rejects. Its limitation is that the oil usually needs further treatment before entering a petrochemical steam cracker. You can see the details of each output in what products pyrolysis generates and what they are for.
Gasification
Gasification treats the waste at high temperature with a controlled amount of oxygen or steam, not enough to burn it completely. The main product is a syngas made up mainly of hydrogen and carbon monoxide, which can be used to produce methanol, other chemicals or energy.
It accepts highly heterogeneous waste, even with non-plastic fractions. In return, it requires large-scale facilities and demanding gas clean-up, and getting back to new plastic takes several intermediate steps.
Depolymerisation and solvolysis
Chemical depolymerisation uses solvents and reagents (water, alcohols, glycols) to reverse the reaction by which the polymer was made and recover its monomers. It is also known as solvolysis, and its variants include glycolysis, methanolysis and hydrolysis.
It works very well with condensation polymers such as PET or some polyamides, and produces high-purity monomers. Its limitation is that it needs relatively pure streams of a single polymer, so it does not solve the problem of mixed plastic.
Chemical versus mechanical recycling: a comparison
| Criterion | Mechanical recycling | Chemical recycling |
|---|---|---|
| Principle | Melt and reshape the polymer | Break the polymer into smaller molecules |
| Waste accepted | Clean, sorted and of a single type | Mixed, contaminated or multilayer (depending on the technology) |
| Product | Recycled pellets | Oil, syngas, monomers |
| Quality after several cycles | Degrades with each cycle | Equivalent to virgin material after refining |
| Energy consumption | Low | Higher, due to the input of heat or reagents |
| Food contact | Only with authorised processes and tightly controlled streams | Possible from monomers or purified feedstock |
It is not a question of choosing: mechanical recycling should make use of everything it can, and chemical recycling should treat what mechanical recycling rejects.
Food-contact grade quality
Food contact is one of the bottlenecks for recycled plastic. Regulation (EU) 2022/1616 on recycled plastic materials and articles intended to come into contact with foods requires authorised and controlled processes. In practice, mechanically recycled food-grade material is scarce outside PET.
Chemical recycling offers another route. When plastic is broken down into starting substances, those substances are treated like any monomer or feedstock: they must appear on the Union list in Regulation (EU) No 10/2011 and must not contain molecules or contaminants from the waste. If those conditions are met, the resulting plastic can be used in food packaging. This makes it especially relevant for polyolefins such as polypropylene or polyethylene, where there is almost no food-grade mechanical alternative.
The role of chemical recycling in the PPWR
Regulation (EU) 2025/40 on packaging and packaging waste, known as the PPWR, was published in the Official Journal on 22 January 2025, entered into force on 11 February 2025 and has applied generally since 12 August 2026.
Recycled content targets for 2030 and 2040
Its Article 7 sets minimum percentages of post-consumer recycled content in the plastic part of packaging:
- Contact-sensitive packaging made mainly of PET: 30 % in 2030 and 50 % in 2040.
- Contact-sensitive packaging made of plastics other than PET: 10 % in 2030 and 25 % in 2040.
- Single-use plastic beverage bottles: 30 % in 2030 and 65 % in 2040.
- Other plastic packaging: 35 % in 2030 and 65 % in 2040.
Meeting the targets for non-PET contact-sensitive packaging with mechanically recycled material is difficult, because that material is scarce. That is where chemical recycling has the most room.
Mass balance: how recycled content is counted
In a chemical plant, pyrolysis oil is mixed with fossil feedstock in the same units. It is not possible to physically separate which molecule comes from the waste. That is why mass balance is used: an accounting system that records how much recycled material goes in and allocates it to the products coming out, with verification along the chain of custody.
The Commission has begun to set the rules. For the single-use beverage bottles covered by Directive (EU) 2019/904, it adopted an implementing decision in 2026 that applies the so-called fuel-use exempt approach: material that is turned into fuel or lost in the process does not count as recycled content. It also requires annual third-party verification at the most complex stages, such as chemical recycling. For the PPWR, the Commission must adopt, before the end of 2026, the implementing act that will set out the methodology for calculating and verifying recycled content.
The practical consequence is clear. European legislation only considers as recycled what is turned back into material. The fraction used as fuel is recovery, not recycling. Certification schemes such as ISCC PLUS and environmental credits are the tool for demonstrating that journey to the buyer.
How Nantek solves it
Nantek uses thermal pyrolysis without catalysts, with in-house developed reactive agents. Its process accepts mixed plastic without prior sorting by type, which is exactly the fraction that mechanical recycling rejects. The technology has been validated since 2022 at its industrial plant in the Port of Bilbao with plastics from a range of sources.
It offers modular plants from 1,500 to 16,000 tonnes a year within an end-to-end model: turnkey EPC with fixed scope and price, structured financing of up to 70 %, O&M with remote monitoring and proprietary software, guaranteed offtake of 100 % of the product under long-term contracts and management of environmental credit certification, with part of the net profit passed on to the client.
Nantek displays the ISCC, ISCC PLUS and CGN certifications on its website and is registered with ECHA. In Córdoba, in 2025 it signed an agreement with Sadeco and the City Council: a first phase of 16,000 t/year with an investment of €22 million and a planned expansion to 54,000 t/year, with €65 million in total. It works with landfills and large waste managers, industry with captive waste and public authorities.
To see which plants and projects exist today, check the map of chemical recycling in Spain; for the regulatory push, see the PPWR and recycled content in packaging.
Frequently asked questions about chemical recycling
Does chemical recycling replace mechanical recycling?
No. They are complementary. Mechanical recycling is more efficient for clean, sorted plastic; chemical recycling treats the mixed, dirty or degraded fraction that mechanical recycling cannot use.
Is pyrolysis chemical recycling?
Yes, it is one of its main technologies. But only the part of the product that is turned back into feedstock for new materials legally counts as recycling. The part used as fuel is considered energy recovery.
Can chemically recycled plastic be used in food packaging?
Yes, if the substances obtained comply with Regulation (EU) No 10/2011 and do not contain contaminants from the waste. This is one of its main advantages over mechanical recycling for polyolefins.
What is mass balance?
It is a verified accounting method that allocates to the end products the amount of recycled material that has entered a process, when that material is mixed with fossil feedstock and cannot be physically separated.
Does chemical recycling count towards the PPWR targets?
The PPWR provides for the Commission to set out, by implementing act, how recycled content is to be calculated and verified. For beverage bottles, the Commission has already adopted rules that accept chemical recycling through mass balance, excluding the fraction used as fuel.
If you manage plastic rejects that you currently pay to dispose of, we can look at whether they would suit a chemical recycling plant. Get in touch and we will analyse the viability of your waste.
