rPET: what makes recycled PET food grade

rPET is polyethylene terephthalate recovered from used packaging and reprocessed into resin. It is the same polyester as virgin PET, but its molecular history and its impurity profile are not. Two things have happened to it. Mechanical recycling has shortened the average chain length. And the material has spent a life in contact with things that were not food.

Those two facts explain almost every question about post-consumer recycled PET, or PCR PET. The shortened chains decide what the recyclate can physically be made into. The contact history decides whether it may legally touch food at all. That second question is answered by an authorisation held by the recycling process, not by the polymer.

Where rPET comes from, and why the source matters

The dominant feedstock for food contact rPET is post-consumer beverage packaging, above all collected bottles. That stream has qualities no other plastic waste stream has. It is collected in very large volumes, it is close to a single polymer, and its previous contents were mostly beverages. Deposit return systems in several countries also keep it separate from the rest of household waste.

The second stream is PET trays and thermoformed packs. It is more mixed, more often coloured or multilayer, and harder to sort. Tray-to-tray recycling is developing. How far it has developed depends on the country, on its collection infrastructure and on how the trays were designed. Bottle-to-bottle remains the established route.

This matters commercially because a specification asking for food grade rPET is, in practice, asking for a share of the bottle stream. Whether that share is available, and at what price, is a question about a national collection system rather than about a converter.

Intrinsic viscosity (IV): what rPET can be used for

Intrinsic viscosity, IV, is the number that describes a PET resin. It is a measure of average chain length, and chain length is what carries mechanical strength. A bottle grade resin needs a higher IV than a film or fibre grade. A bottle has to survive being blown, filled and pressurised.

Every pass through an extruder lowers it. PET degrades in two ways at melt temperature: thermally, and hydrolytically if any water is present. Both break chains, so IV falls. A recyclate is therefore not simply PET, it is PET at a lower IV than the material it came from.

The practical consequence for a buyer is that IV belongs in the specification. Batch to batch variation in IV is a real risk with recyclate, in a way it is not with virgin resin.

Why PET has to be dried and polyolefins do not

PET is hygroscopic: it absorbs moisture from the surrounding air. Polyethylene and polypropylene barely do, because they are non polar and have nothing for water to bond to. PET has ester groups, and water attacks exactly those.

If wet PET is taken to melt temperature, the water hydrolyses the ester links and cuts the chains. IV falls sharply within minutes. Drying before processing is therefore not a precaution, it is part of the process. With recyclate the point is sharper still. The material starts from a lower IV, so it has less margin to lose before it stops meeting the specification.

Food-grade rPET in the EU: Regulation (EU) 2022/1616

In the European Union the authorisation belongs to the process, not to the polymer. Recycled plastics intended for food contact are governed by Commission Regulation (EU) 2022/1616 of 15 September 2022, as amended. It entered into force on 10 October 2022 and repealed Regulation (EC) No 282/2008. It is built on a distinction that matters commercially. Safety is demonstrated at three levels: the technology, the individual process, and the installation where that process runs.

Post-consumer mechanical PET recycling is the route with an established pathway under that framework, and an individual recycling process using it requires authorisation. The decontamination efficiency of a process is assessed scientifically, and EFSA has published guidance specifically on evaluating post-consumer mechanical PET recycling processes. Recyclers, processes, schemes and decontamination installations are entered in a Union register.

Bottles and film draw on the same stream

Two separate pieces of EU law now put demand on the same bottle stream. Neither of them was written with flexible packaging in mind.

The Single-Use Plastics Directive, Directive (EU) 2019/904, requires PET beverage bottles to contain 25 per cent recycled plastic from 2025. From 2030 the requirement becomes 30 per cent. It then applies to all plastic beverage bottles covered by the Directive, not to PET alone. The Packaging and Packaging Waste Regulation then sets its own minimums. They are calculated per packaging type and format, as an average per manufacturing plant and year, rather than pack by pack. One of those figures applies specifically to contact-sensitive packaging with PET as the main component.

Bottle producers and film producers are therefore buying from the same collected material, under legal obligations that both increase over time. That is the structural reason competition for high quality food contact feedstock is intense. It can support a price premium over virgin resin whenever regulatory demand runs ahead of supply. Relative prices still move with energy costs, collection rates and quality, so the premium is a tendency rather than a constant. The thresholds themselves, and how content is counted, are set out under recycled content requirements.

How recycled PET changes finished film properties

Four things show up in the film rather than on the certificate. Each one follows from the input being a collected waste stream rather than a reactor output.

• Colour. The input was never one colour, and PET yellows slightly with each heat history. A high recycled content and a water-clear film therefore pull against each other.
• Gels and specks. Contaminants that did not melt, or that degraded, stay visible in a transparent film. In an opaque one they would not.
• Acetaldehyde. PET generates it as a degradation product, and it can be tasted in low aroma products such as water. How much matters depends on the grade, the residence time and the processing conditions. That is why those conditions are controlled tightly.
• Variation. IV, colour and contamination all shift between batches. A structure with a wide processing window tolerates recyclate better than one running at the edge of its limits.

None of these rules recyclate out. They decide where it goes. In a multilayer film recycled content is often placed in an internal or non-contact layer. The grade, the optical requirement or the application can make that the easier route. It is a design choice rather than a rule, because rPET from a process authorised for food contact can be used in contact applications, within the conditions of that authorisation. The same reasoning applies to recycled polyethylene.

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