Using recycled plastic materials in injection moulding is an industrial reality, not just a marketing argument. It responds to growing regulatory pressures (Single-Use Plastics directive, European plastics tax, extended producer responsibility schemes) and to concrete B2B client requirements integrating CSR objectives into product spécifications. It also poses specific technical constraints that any serious injection moulder must master. This guide details what working with recycled materials in injection moulding means: which grades are available, what properties to expect, how to validate them and how to document recycled content in your value chain.
Recycled grades in injection moulding
Not all plastics recyclé with the same yield or residual properties. In injection moulding, the most common PCR (Post-Consumer Recycled) grades are rPP (ex-food and household packaging), rPET (ex-bottles), rHDPE (ex-bottles and containers) and rABS (primarily from waste electrical and electronic equipment, or WEEE).
Each recyclable material has its own processing specificities. rPP is the most accessible: good availability, common certified grades, broad compatibility with packaging and everyday use applications. rPET requires rigorous drying and précise injection températures. rABS shows colour and viscosity variability that demands lot-by-lot qualification. rHDPE is robust but requires particular attention to cross-contamination.
There are also materials from industrial recycling, called PIR (Post-Industrial Recycled), which correspond to uncontaminated production waste. These grades are technically more homogeneous than PCR and often easier to qualify for technical applications.
Technical constraints of moulding with recycled materials
Injection moulding with recycled materials introduces variability that a serious spécification and qualification process must anticipate.
Lot-to-lot variability is higher with PCR than with virgin grades. Melt flow index (MFI), viscosity and mechanical properties can vary between two lots of the same grade. An incoming material qualification protocol is therefore necessary: MFI measurement, tensile and impact tests, visual particle size check.
Colour feasibility is often limited. Recycled materials have a residual tint (often beige to brown for rPP, grey-black for rABS) that makes pale colours and bright tones difficult without a covering agent. Applications requiring specified RAL or Pantone colours must integrate this constraint from design stage.
The présence of contaminants is a risk to manage. Even certified PCR grades may contain tracés of foreign materials. For applications with Class A surface requirements or food contact, rigorous grade sélection and specific qualification are mandatory.
Some technical materials (PA, PC, POM) tolerate regrinding of internal waste at controlled proportions, generally between 15 and 20 per cent of the blend. Beyond this threshold, mechanical properties and dimensional stability may dégradé. We validate these thresholds through systematic mechanical testing.
Our zero-waste production policy
Before addressing post-consumer recycled materials, our approach starts with eliminating internal production waste.
100 per cent of our production waste, whether sprues, non-conforming parts or purges, is ground on-site and reintroduced into the process. Our centralised grinding system, connected to each press, enables immediate recycling without dégradation of mechanical properties.
For technical materials, we maintain a controlled regrind rate validated by regular mechanical tests. This practice reduces material waste, lowers raw material costs and forms a documentable élément in the carbon footprint of each production run.
Mould design for the circular economy
The circular approach does not start at production: it starts at mould design.
Hot runner systems eliminate sprues and save a significant share of material compared to traditional cold runner systems. This saving is particularly relevant for technical or high-value material parts.
Wall thickness optimisation through Moldflow simulation reduces part mass without compromising mechanical properties. Less material per part means less material to recyclé at end of life.
Mono-material design, where functional constraints allow, facilitates end-of-life product recycling. A mono-material part is sortable and recyclable; a 2K part or one assembled with a métal insert requires séparation before recycling. LGR Design Studio integrates these eco-design criteria from the earliest development phases.
Certifications and recycled content traceability
Documenting recycled content has become a key élément of product files, particularly in sectors subject to the SUP directive, REP requirements or the European plastics tax.
We ensure complète traceability for every material lot used: grade, supplier, analysis certificate, declared recyclable material rate, production batch. This information is available on request as a product traceability report.
The PCR grades we use are certified by independent bodies (EuCertPlast, among others). These certifications attest to the actual recycled content of the grade and allow it to be inserted into your own environmental product déclarations (EPD) or a life cycle assessment (LCA).
We can provide simplified LCAs on request, calculated project by project, to allow you to integrate carbon footprint data into your CSR reporting or tender responses.
Carbon footprint: the key figures
Using recycled plastic materials reduces the material carbon footprint, sometimes very significantly. Data from recognised LCA databases indicate substantial réductions compared to équivalent virgin grades. Precise quantification depends on the polymer, recycling process and waste source.
These figures are not only communication arguments. They allow demonstrating compliance with requirements of certain responsible procurement programmes, meeting award criteria in public or private tenders, and calculating the impact of your material choices on the overall carbon footprint of your product.
When to use recycled materials in injection moulding?
The décision to introduce recycled materials into a product must be evaluated case by case. It is relevant when the mechanical and functional performance requirements of the product are compatible with the properties of available PCR grades, when the colour constraint is managed from design, and when the regulatory or commercial value of recycled content is documented and leveraged.
It requires serious qualification of the selected grade, lot-by-lot quality monitoring and précise communication on the actual recyclable material rate to avoid greenwashing risks.
We support our clients through this évaluation: technical feasibility analysis, grade sélection, qualification protocol, certified recycled content documentation.
You have a project with recyclability requirements?
Send us your spécifications with recycled content and product performance requirements. We analyse technical compatibility with available PCR grades and propose a complète qualification plan.
FAQ
FAQ
Are recycled plastic parts as strong as virgin material parts?
For most applications, yes. The certified PCR grades we use reach mechanical properties close to équivalent virgin grades. For critical applications (médical, automotive, safety), we validate each grade through specific tests before production start.
Can recycled plastic be used for food contact applications?
Yes, under conditions. Certain rPET and rHDPE grades are certified to EU 10/2011 and FDA for food contact. rPP for food contact is under development but certified injection grades remain limited. We systematically document food contact compliance for every grade used.
How do you certify the recycled content of your parts?
We use EuCertPlast-certified PCR grades. On request, we provide a lot-by-lot traceability report documenting the grade used, supplier, analysis certificate and declared recyclable material rate. This data is directly usable in your environmental product déclarations or CSR reporting.
Which recycled polymers do you offer in injection moulding?
We primarily work with rPP, rPET, rHDPE and rABS in certified PCR grades. For specific projects, we can source other PCR or PIR grades depending on technical requirements and volumes. Each grade undergoes qualification before séries production.
Can you calculate the carbon footprint of a production with recycled materials?
Yes. We calculate the carbon footprint of each project on request, integrating the nature of the material (virgin or recycled and rate), the injection process and logistics flows. The calculation is based on data from recognised LCA databases and is provided as a project report.
