Polymer recyclates (rPET, rHDPE, rPP): properties, transport and PPWR requirements

Definition

Polymer recyclate is a plastic derived from waste recovery, processed back into a form suitable for reprocessing instead of virgin raw material. In commercial and transport circulation it occurs most often as regranulate — a pellet obtained by washing, melting and granulation, technologically close to granulate from the first polymerisation. The three most important types are rPET (from beverage bottles), rHDPE (from rigid packaging) and rPP — the fastest-growing polyolefin recyclate in Europe.

Over more than thirty years of working at the terminal in Chorula I have travelled the whole road of this material with recipients: from the time when recyclate was a niche product treated with suspicion, to today’s situation in which the PPWR regulation makes it a mandatory component of packaging. From the standpoint of bulk materials logistics, regranulate is simply another polymer granulate — but bound by a stricter cleanliness and documentation regime than virgin raw material.

Recyclate versus regranulate — and two recycling methods

In conversations with customers the two terms are sometimes confused, so it is worth separating them precisely.

Recyclate is the broader concept — it covers any plastic from recovery, regardless of form. It can be regrind, flake after washing bottles, or finished granulate. Regranulate is the specific, final form: a homogenised pellet after melting and granulation. For the terminal and the processor it is the regranulate that counts, because it has a repeatable bulk density, pours like virgin raw material and is suitable for bulk transport by silo tanker.

The second key distinction concerns the recovery method:

• Mechanical recycling — shredding, washing, sorting and melting of waste without changing the chemical structure. The polymer remains the same polymer; PET is still PET, only with a slightly lower molecular weight. This is the dominant method, cheaper and the most energy-efficient, but sensitive to the cleanliness of the waste stream.
• Chemical recycling — depolymerisation of the plastic into its starting compounds (monomers, oligomers or other fractions), from which the material is re-synthesised. It allows a product of virgin quality to be obtained, cleaned of additives and dyes, but is more expensive and still being developed at industrial scale.

In practice, most of the regranulate that passes through the terminal comes from mechanical recycling, increasingly compounded with an admixture of virgin raw material to even out properties. Chemical recycling is beginning to appear for rPET intended for food contact, where the cleanliness requirement is highest, but by volume it is still a market margin.

It is also worth remembering a third, simplest route: in-plant recovery. Rejects, sprues and production waste return to the process at the processor’s own site and do not enter commercial circulation as regranulate for sale. For the terminal what counts is the regranulate that travels from the recycler to a new recipient — and it is this that is subject to the full bulk material transport regime.

Main types of recyclates

rPET is the best-developed recycling chain in Europe, mainly thanks to bottle-collection systems (deposit). It is also the only widely available recyclate in food-grade quality, i.e. approved for food contact — provided it has been processed in a decontamination process positively assessed by EFSA. The virgin material to which it refers I described more broadly in the article on PET — polyethylene terephthalate.

rHDPE comes from rigid packaging — canisters, household-chemical bottles, caps — and is the basic polyolefin recyclate; details of the base plastic can be found in the article on polyethylene. rPP is currently the fastest-growing segment of polyolefin recyclate in Europe — demand is driven by the automotive industry and transport packaging, and supply rises along with improvements in optical sorting and collection systems.

One of the important differences between these streams is colour stability. Bottle rPET is sometimes transparent or slightly bluish and can be coloured; rHDPE and rPP from a mixed packaging stream are usually grey or black and are intended for applications where colour does not matter — pipes, pallets, technical packaging. This distinction affects how the processor plans batches and how batches are segregated as early as the storage level.

Nomenclature and designations

In specifications and material data sheets one encounters several designations worth not confusing:

• The “r” prefix — denotes recyclate: rPET, rHDPE, rPP, rLDPE.
• PCR (post-consumer recycled) — raw material from post-consumer recovery, i.e. from waste after use by the consumer. It is precisely PCR that counts towards the PPWR thresholds.
• PIR (post-industrial recycled) — raw material from industrial recovery (production waste, sprues, rejects). Cleaner, but treated differently from PCR for regulatory purposes.
• % recyclate share — the declared content of recovered raw material in the finished packaging or regranulate.

The PCR/PIR distinction is key when accounting for PPWR obligations, because the regulation rewards post-consumer recovery — the hardest to organise but the one that closes the loop.

PPWR requirements — minimum recyclate shares

The Packaging and Packaging Waste Regulation (PPWR) is today the main driver of demand for regranulate. It introduces mandatory minimum shares, rising over time, of recyclate from post-consumer recovery in plastic packaging:

The thresholds are calculated as an average per production plant and year, not piece by piece — which gives producers flexibility in balancing their portfolio. The practical consequence is, however, unambiguous: every large packaging producer must have a stable, high-quality source of regranulate, and this translates into a growing stream of material through transloading terminals. The regulatory details and documentation obligations I developed in a separate article on PPWR and recyclates in packaging.

Properties and quality of regranulate

The most frequent myth I encounter is: “recyclate is an inferior plastic.” This is an oversimplification. True, every melt cycle degrades the polymer — the average molecular weight drops, yellowing may rise, the melt flow index shifts, and trace contaminants accumulate over successive loops. But the scale of this degradation depends on the discipline of the process and is not inevitable.

In practice the quality of regranulate is raised by:

• compounding with an admixture of virgin raw material or refining additives,
• stabilisers (thermal and antioxidants) that limit degradation during melting,
• chain extenders that raise the viscosity of rPET to bottle level,
• selective sorting of the waste stream, which determines the cleanliness of the feed.

Well-managed regranulate can go through several cycles before its properties fall below the threshold of usefulness for a given application. That is why products are increasingly designed to take recyclate input into account from the start — this is the philosophy of design for recycling.

From the recipient’s point of view, the most important parameters they read from a regranulate data sheet are: MFR (melt flow index, deciding processability), density, moisture content (especially critical for rPET, which is dried before processing), foreign-fraction content and — for food-grade — the result of migration tests. The first two decide whether the regranulate will behave on the processor’s machine like the virgin raw material it is used to. Contamination with a foreign polymer is the hardest to remove: a grain of PP in an rPET stream can ruin a whole batch of bottles, because polymers with different melting temperatures do not mix uniformly. Hence the great weight of sorting at the input and cleanliness control at the output.

Commercial form and transport

From the terminal’s perspective, regranulate behaves like any other polymer granulate: a 2–5 mm pellet, a bulk density close to virgin raw material, the same logistics. It is supplied in two main forms:

• in bulk in a silo tanker — to the processor’s silo, when the stream is steady and large; the silo-tanker technique I describe in the article on silo tankers,
• in FIBC big bags 1000 kg — when the recipient works in batches or needs to segregate batches; packaging details are in the article on FIBC big bags.

Here comes the point that is critical for recyclate: cleanliness and the absence of secondary contamination. Food-grade regranulate that is to return to beverage bottles must not pick up dust, foreign grains or residues from a previous load along the way. That is why at the Chorula terminal we treat recyclate with a cleanliness regime identical to virgin granulate: control on cleaning sieves, loading into a verified, dry silo tanker and — most importantly — gentle, gravity-fed transloading without excessive pneumatics. High-pressure pneumatic conveying generates dust and “angel hair”, which in regranulate are even more undesirable than in virgin raw material, because they spoil the cleanliness parameter that decides food-grade status.

Operationally, the most frequent service for us is big bag to silo tanker transloading: regranulate arrives from a sorting plant or recycler in big bags and leaves in bulk to a large processor. The regular warehouse handling of such materials I describe in the storage section.

The recyclates rPET, rHDPE and rPP are inert thermoplastics — they are not dangerous goods (ADR) and require no procedures for hazardous materials. From our experience with the plastics industry’s regular customers — LG Chem, Borealis, Synthos, Orlen — recyclate increasingly flows through the same logistics channel as virgin granulate, only with stricter documentation of origin.

Traceability and batch separation

There is one more dimension that cannot be overstated with recyclates: traceability. A packaging producer declaring a 30% PCR share in a bottle must document that share for PPWR purposes. This means the regranulate supply chain — from the recycler, through the terminal, to the processor — must preserve a trace of the origin of every batch. In terminal practice this translates into several hard rules:

• batch separation — a batch of regranulate does not mix with virgin raw material or with another recyclate batch; each travels separately or with full feed documentation,
• clean, verified silo tankers — before a food-grade load the silo tanker undergoes a cleanliness check, and the previous load must be compatible with it,
• control on sieves — catching foreign grains, dust and agglomerates that would lower the cleanliness parameter,
• transloading documentation — who, when, from which batch, into which silo tanker.

With a 2000-big-bag warehouse and a 200 t/day throughput, we balance such regranulate batches together with the virgin raw material stream, but we never combine them without the recipient’s explicit consent. In my experience it is precisely the discipline of separation, rather than the transloading technology itself, that decides whether food-grade regranulate will reach the bottling plant without complaints.

Recyclate in the circular economy — the terminal’s perspective

Looking at it from the ramp: recyclate has ceased to be a niche product and has become an element of the regulatory strategy of every large packaging producer in Europe. The PPWR is not a declaration of intent — it is hard thresholds with dates, which force a physical flow of regranulate on the scale of millions of tonnes a year. And regranulate, like any polymer granulate, has to be transloaded, stored and delivered to the processor intact.

For the terminal in Chorula this means a growing stream of material that we technically handle identically to virgin raw material — by silo tanker or big bag, by gravity, without excessive pneumatics — but with a stricter cleanliness and documentation regime. This is a good example of the fact that in bulk materials logistics what counts is not only what is carried, but how cleanly and with what traceability. For recyclate these two parameters are just as important as the polymer specification itself.

Related topics

• PET — polyethylene terephthalate — the virgin raw material for food-grade rPET.
• Polyethylene (PE) — the base for rHDPE.
• PPWR and recyclates in packaging — regulatory thresholds and obligations.
• Cleaning sieves — granulate cleanliness control during transloading.

Sources

• Regulation of the European Parliament and of the Council (EU) on packaging and packaging waste (PPWR) — minimum recyclate-share thresholds.
• EFSA guidelines on the recycling of plastics intended for food contact (food-grade rPET).
• Practice of the SMIALA / PHS Magnum transloading terminal in Chorula — magnumchorula.pl/transport/.
• Aleksy Pasternak, over 30 years of terminal practice — pasternak.me.