Recycled PP and PE patent landscape: teaching the unmixable to blend
Polypropylene and polyethylene together account for roughly two thirds of global plastics production — yet at the molecular level they are incompatible: they separate in the melt, and after crystallization the blend turns brittle. That is why a mixed post-consumer PP/PE stream was treated for decades as a second-grade feedstock. We reviewed the open patent databases and gathered the key documents of 2014–2019 to see how industry patents the "repair" of recycled polyolefins — and what already works today for the quality of the pellet you buy.
The gist in 30 seconds Our curated sample holds 7 patent families with 2014–2019 priorities, and they map precisely the three fronts in the fight for recycled PP/PE quality: compatibilization of the incompatible phases (3 families), deodorization and volatile-compound control (3 families), and deep solvent purification (1 family). The most consistent corporate player is Borealis, with three families — from compatibilizers for PP/PE blends to reduced aldehyde content in recyclates. Tellingly, it is not only the majors who file: the University of Alicante carried its odor-removal system through to granted patents in the EU and the US, and a consortium of Korean companies patented a deodorizing masterbatch. Recycled-polymer quality has become the subject of a patent race — which is the best possible news for those who use it.
What question this landscape answers
For an engineer considering recycled polypropylene or polyethylene, the doubts are always the same: unstable mechanics, odor, and an unknown feedstock history. All three share a single root — a post-consumer stream is not "PP" or "PE" but a blend of polyolefins carrying residues of other polymers, printing inks, and oxidation products.
The patent landscape here answers a practical question: which technologies does industry consider valuable enough to protect with patents. Where patents accumulate, there is real money and real engineering — solutions that gradually reach series-produced recyclates. For a buyer of recycled feedstock, this is a map of what to ask a supplier about.
Methodology
The source is the open Google Patents database; searches covered PP/PE blend compatibilization, deodorization of recycled polyolefins, and purification of post-consumer polypropylene. The sample comprises 7 patent families with 2014–2019 priority dates; we opened each document and verified the applicant, dates, and substance against the primary patent page. This is deliberately a curated qualitative slice, not a statistical landscape over thousands of records: it shows directions and players but does not claim completeness. The geography of the families is telling, though — individual documents were granted or published in the US, EU, China, Korea, Japan, Brazil, Canada, and Taiwan, meaning protection is being built for a global recyclate market.
Key players: a producer, a consumer-goods giant, and a university
Borealis — the most consistent corporate line in the sample. The Austrian polyolefin producer protects the full chain of working with recyclate. The WO2015169690A1 family (2014 priority) describes PP/PE blends with 10–25% of a heterophasic compatibilizer that simultaneously raise Charpy impact strength, flexural modulus, and heat resistance — exactly the combination that "falls apart" in uncompatibilized blends. The WO2020089196A1 family (2018 priority) is an "upgrade" of a finished recycled PP/PE blend plus 3–20% of a plastomer with tightly defined selection criteria. And EP3763777B1 (2019 priority, granted in the US as US11518863B2) targets the chemistry of odor — reducing the aldehyde content in the recycled polyolefin.
Dow approached from the side of molecular architecture: the WO2015057423A1 family (2014 priority, granted in the US as US9752024B2) protects PE + PP compositions with a crystalline block composite — a block copolymer in which one block crystallizes together with the polyethylene phase and the other with the polypropylene phase, stitching the interphase boundary. This is the patent embodiment of the very idea that science proved experimentally: in 2017 Geoffrey Coates's group showed in Science (Eagan et al., 2017) that PE/iPP tetrablock copolymers turn a brittle blend of two incompatible polyolefins into a mechanically tough material.
Procter & Gamble is an unexpected player at first glance: the consumer-goods giant patented not a formulation but a deep-purification process. Patent US9834621B2 "Method for purifying contaminated polypropylene" (filed 2016, granted 2017, in force) describes the sequence "solvent extraction → polymer dissolution → purification on solid sorbents → recovery of purified PP." This very technology platform is licensed to PureCycle Technologies, which is building industrial capacity on it to restore PP to a near-virgin state.
The University of Alicante (Spain) proves that the odor topic of recycled plastics has matured in the academic sector too — and did not stay on paper: the WO2020245476A1 family (2019 priority) was carried through to grants in the EU (EP3981486B1) and the US (US12258451B2). And back in 2015 a Korean consortium of TK Chemical, PBR Chemical, and InTechnology patented a deodorizing masterbatch for processing plastic waste (granted 2017, in force) — an example that mid-sized companies, not only the majors, file in this niche.
Technology tracks: three axes of recycled-polyolefin quality
Axis one — blend mechanics. A compatibilizer is a molecular "seam": a block or heterophasic copolymer whose parts are compatible with the different phases of the blend. The sample patents show the evolution of the approach: from heterophasic compositions (Borealis, 2014) through crystalline block composites (Dow, 2014) to ready formulas for upgrading precisely the recycled blend with clear plastomer input criteria (Borealis, 2018). The practical consequence for a processor: a modern recycled PP/PE compound is no longer "we pelletized whatever arrived" but a controlled formulation.
Axis two — odor. Volatile organic compounds in the post-consumer stream are oxidation products, residues of packaging contents, and inks. The patents attack them at different stages: an adsorbing masterbatch straight into extrusion (the Korean consortium), steam stripping in a column after surfactant washing (Alicante), targeted aldehyde reduction (Borealis). Odor has ceased to be "the inevitable price of recyclate" — it is a controllable quality parameter, and it is worth asking a supplier about it just as you would about MFR.
Axis three — purity. The P&G/PureCycle solvent platform is the most radical route: the polymer is dissolved, passed through solid sorbents, and the purified PP is recovered. This is already the boundary between mechanical and physicochemical recycling, and the stakes are highest here — from color and odor to suitability for demanding applications.
Two patents in close-up
WO2020089196A1 (Borealis): upgrading a recycled blend by formula. The composition consists of 80–97% recycled PP/PE blend (in a ratio from 3:7 to 7:3), 3–20% of a plastomer compatibilizer, and up to 1% stabilizers. What is interesting is not the idea of "adding a plastomer" but the strictness of the criteria: a plastomer melting point below 75 °C by DSC, a melt flow rate no higher than 1.5 g/10 min (190 °C/2.16 kg), a density no higher than 885 kg/m³, plus a specified ratio of the melt flows of the blend and the compatibilizer. This is an engineering recipe with tolerances — the patent effectively formalizes what the modifier must be in order to "lift" the recyclate predictably rather than by guesswork.
WO2020245476A1 (University of Alicante): odor is removed by a system, not a single operation. The patent describes a full-cycle sequence: grinding to powder-like particles, chemical washing with surfactants in a stirred tank, rinsing in a reactor, mechanical drying, and — the key stage — stripping the volatile compounds with steam in a distillation column, from the bottom of which the purified plastic exits. The message for the industry is clear: the persistent odor of recycled feedstock is not "washed out" by any single operation — it is removed only by a linked chain of stages designed around VOCs.
What this means for a Ukrainian producer and R&D
The patent landscape prompts the buyer of recycled feedstock with the right questions. If global players patent compatibilization, deodorization, and purification, then those are precisely the axes by which pellet quality is measured. Ask the supplier: what has been done about phase compatibility in the PP/PE blend; how are volatile compounds and odor controlled; what is the feedstock history and batch stability. "Just re-pelletized" is no longer a sufficient answer in 2026.
Material Wizard develops the recycled-polyolefin direction in exactly this logic: recycled PP and PE with feedstock-origin control and incoming batch inspection, with an honest TDS — and where the task demands guaranteed mechanics or food contact, we openly recommend virgin materials from the Examid®, Exablend®, and Exaflex® ranges. We have already written in detail about the practical side of the choice: how recycled PP behaves outdoors under UV and what is special about recycled polyamide; for the patent history of a neighboring material class, see the TPU landscape.
Expert review: 5 questions about the patents around recycled PP/PE
Does a processor need a license to work with recycled PP/PE?
No: pelletizing, molding, or extruding recycled polyolefins in themselves require no licenses. The sample patents protect specific formulations of compatibilized compositions and specific purification processes. Checking patent clearance is worthwhile only when you reproduce someone else's protected solution one to one — for example, copying a patented blend-upgrade formula.
Why does a PP and PE blend need to be "stitched" at all?
Although both polymers are hydrocarbon polyolefins, their chains do not mix at the molecular level: the blend forms separate phases with a weak interface, and it is along that interface that the material cracks. A compatibilizer — a copolymer whose blocks are compatible with both phases — works as a molecular seam, and the blend's mechanics rise sharply.
Is the odor of a recycled pellet forever?
No, and the patent landscape confirms it: the problem is attacked with adsorbing masterbatches, steam stripping, and aldehyde chemistry. But no single operation gives a full result — linked chains of stages do the work. In practice: the odor level differs substantially between suppliers, so request samples and evaluate precisely the batch you intend to buy.
What is a "near-virgin" recyclate, and is it available yet?
It is a recycled polymer after deep physicochemical purification — for example by the solvent technology licensed by P&G to PureCycle: dissolution, purification on sorbents, recovery of pure PP. Industrial capacity is coming online, but in the mass segment the foundation remains high-quality mechanical recycling — which is why incoming batch inspection is critical.
How do I tell whether recycled PP/PE will suit my part?
Start from the part's requirements, not from the price per kilogram: you need mechanics, dimensional stability, odor, color, and processing window. The rational path is to outline the task to a specialist, obtain a TDS and samples of a specific batch, and run a trial molding. Recycled PP and PE from Material Wizard are available with delivery across Ukraine; if the task is at the edge of what recyclates can do, we will say so honestly and propose a virgin alternative.
Sources: Borealis GmbH: WO2015169690A1, WO2020089196A1, EP3763777A1/B1 (US11518863B2); Dow Global Technologies LLC: WO2015057423A1 (US9752024B2); The Procter & Gamble Company: US9834621B2, PureCycle licensing — PureCycle press materials, Waste Dive; Universidad de Alicante: WO2020245476A1 (EP3981486B1, US12258451B2); TK Chemical / PBR Chemical / InTechnology: KR101691878B1; science: Eagan J.M. et al. "Combining polyethylene and polypropylene: Enhanced performance with PE/iPP multiblock polymers", Science 355, 814–816 (2017), DOI 10.1126/science.aah5744.
Material Wizard is a manufacturer and supplier of engineering polymers. Locations: Derazhnia and Kharkiv. Recycled PP and PE, as well as virgin Examid®, Exablend®, and Exaflex® grades, are available with delivery across Ukraine — confirm supply terms and grade selection with a specialist.