hffr-Up2Cycle - Sustainable and closed loop solutions of flame retarded plastics in electric and electronic, automotive and cable applications

The hffr-Up2Cycle project aims to increase the sustainability of plastic materials formulated with flame retardeds. By studying and optimizing recycled and processed PCR (post-consumer recycling) materials such as polyolefins (PP, PE), PET, PC/ABS, PA and flexible PU foam, the aim is to improve their flame retardancy and enhance their long-term mechanical and thermal properties, as well as simulate their stability in closed loop applications.

The recycling of polymeric materials is crucial for ecological, economic and social development. With the upcoming regulations of the European Green Deal setting specific recycling quotas, the plastics industry is facing major challenges. In particular, flame-retarded plastics require innovative approaches due to the lack of existing flame-retarded PCR waste streams.

Challenges:

• Sustainable materials: The increasing demand for environmentally friendly materials requires new recycling methods.
• Recyclability: Halogen-free flame-retarded plastics are an environmentally friendly alternative, but the data about their recyclability is still low.
• Safety standards: High-quality applications require often flame retardeds, which present additional challenges when using recyclates.

The objectives of the hffr-Up2Cycle project are to

• Improving the recyclability of halogen-free flame-retarded (HFFR) plastics.
• Developing innovative recycling methods and Re-Stabilization strategies to improve the quality and sustainability of materials.
• Opening up new perspectives by upcycling packaging waste and recycling of hffr-plastics from closed-loop systems.

Goals and objectives

The main objectives of the hffr-Up2Cycle project are:

• Mapping and characterization of PCR materials available on the market from various sources, such as packaging and high-quality applications.
• Identification of strategies to increase sustainability in selected applications through the use of PCR, including customized formulations for injection moulding in the electronics, electrical engineering, automotive, cable and construction sections.
• Development of flame-retarded formulations based on the selected PCRs that are suitable for the respective applications.
• Analytical evaluation of the interactions between flame retardeds and other additives in PCR polymers.
• Establishing a strategy for re-stabilization and polymer mixing over several recycling cycles to maintain flame retardancy and mechanical properties at an applicable level.

Methods and approach

The project methodology involves several steps:

• Material selection: Selection of PCR materials based on availability and upcoming regulations.
• Analytics and characterisation: Detailed investigation and characterization of each waste stream.
• Formulation and compounding: Selection and testing of flame retarded systems in close consultation with the participating companies.
• Durability during ageing and recycling: Investigation of the process and long-term properties of the flame-retarded recyclates.

1. Material selection

In this step, ways to increase the sustainability of flame-retarded plastic compounds are identified. This can be done by upcycling packaging PCRs, upcycling PCRs from high-quality applications or reusing closed-loop recyclates. Materials are selected based on material availability and future regulations (e.g. closed-loop requirements). Market-available PCRs will be selected that originate from waste streams fed by end-of-life materials, such as deposit systems, kerbside collections (e.g. Yellow Bag in Germany) or residual waste. For applications with closed-loop requirements, exemplary waste stream materials, in particular recyclates from flame-retarded applications, will be selected. The aim is to select 5-7 representative PCRs that are available on the market.

2. Analytics and characterisation

After the material selection, a detailed analytical examination and characterisation of each waste stream is carried out, including PP, PE (HDPE, LLDPE), PET (PET/GF), PC/ABS, PA6 and PA66 as well as mixtures (e.g. PP/PE). The characterisation is based on standardised methods (OIT, TGA, DSC, IR, NMR) and mechanical tests (elongation at break, tensile strength). The flame retardeds in the closed-loop recyclates are determined using spectroscopic methods, and the bromine content is also analysed. The aim is to fully characterise each selected waste stream.

3. Formulation and compounding

The selection of the flame retarded systems is done in close consultation with the participating companies. Compounding and testing of the flame retardancy (e.g. UL-94, LOI, cone calorimetry, CTI, GWIT) is a key point for the evaluation of the flame-retarded recyclates. The influence of the deviation of the PCR quality on the flame retardancy is also considered. The addition of new material is evaluated to achieve stable flame retardancy. The aim is to provide a statement on the flame retardancy of the recyclates based on the analytical results depending on selected PCRs and their quality. For each application/polymer waste stream, 2 to 3 compounding sessions with several formulations per session are carried out.

4. Durability during ageing and recycling

The formulations will be used to study the process and long-term properties of the flame-retarded recyclates. The optimisation of materials during plastics processing and accelerated ageing (oven ageing up to 2000 hours) will be evaluated by means of analytical characterisation and tensile tests. The effective interaction of all additives in the compound is analysed in order to optimise the properties of the recyclates depending on the waste stream and its quality. To simulate the effectiveness during closed-loop processes, the recycling durability is evaluated by multiple extrusion. After the extrusion, post-additivation concepts are tested. Recycling durability includes flame retardancy tests and mechanical properties as well as analytical methods to determine polymer degradation. The aim is to select waste streams that result in high-quality flame-retarded compounds comparable to those of virgin materials. For the closed-loop materials, stable flame retardancy should be achieved over several extrusion processes, including a concept for post-additivation.

Expected results

The project aims to ensure that the developed flame-retarded recyclates have similar properties to virgin materials and remain stable in closed-loop recycling processes. This will be achieved by optimising the additives and comprehensively evaluating the recyclability.

Shareholdings and partners

The Fraunhofer Institute for Structural Durability and System Reliability LBF is the project manager. The main stakeholders include companies from the plastics processing and plastics production industries, which are working together on the development and optimization of the Materials.

Relevance and benefits

The results of the project will help to increase the sustainability of plastic materials and meet recycling quota requirements. This opens up opportunities for industry to develop innovative and environmentally friendly solutions while ensuring the safety and quality of materials.