High quality recycling of plastics using the CreaSolv® Process

© Fraunhofer IVV

Our patented CreaSolv® Process provides excellent value-creation. Special purification processes effectively separate contaminants and harmful materials. The plastics that are recycled from contaminated mixtures or composite materials have properties equivalent to those of the virgin plastics.

The recycling of type-pure plastic waste fractions is established and common practice. Sorting and treatment processes for mixed post-consumer waste containing adherent contaminants have been developed for plastic packaging materials.

However, for many post-consumer mixtures of plastics, for example those with similar density, there is however still a lack of available separating technologies for removing the external contaminants. The Fraunhofer IVV is currently carrying out work in the following areas on the separation and purification of plastics and reuse of the type-pure materials:

  • separation of PET-PVC mixtures;
  • separation of ABS-HIPS mixtures;
  • separation of plastic-metal laminates.

The separation of internal contaminants is the second main focus of our work. We provide unique solutions for example for the:

  • separation of barrier materials, pigments and fillers from PET;
  • separation of plastics containing flame-retardants from those not containing flame-retardants;
  • removal of brominated flame-retardants from waste plastics from the electrical industry.

Our recycling processes are hence competing with feedstock recovery and waste site disposal. The feedstock recovery processes are not viable due to costly extra payments having to be made and have mostly been stopped. Waste site disposal will also not be applicable with expiry of the TASi (Technical Guideline for Municipal Wastel) implementation deadline on 1 June 2005 for mixed, energy-rich (namely plastic-containing) waste. In contrast, the Fraunhofer processes also offer value-creation due to the pure, high-quality and quality assured plastic recyclates.

These R&D activities can also summarized by the applications of the plastics:

  • recycling of packaging plastics (PET and EPS);
  • recycling of industrial plastics (ABS and HIPS).

The CreaSolv® Process

The term selective extraction describes a mechanical recycling process for plastics which allows very pure plastics to be recovered due to their specific solubility. The special feature of the method is the fact that the material is purified at the molecular level. Contaminants that are detrimental to quality are removed under mild conditions and with maintenance of the polymer properties.

In conjunction with CreaCycle GmbH in Grevenbroich, a formulator spezialized in the application of solvents with the lowest possible risk potential for the user and the environment (ideally not classified according to GHS creteria), the technique was developed into the CreaSolv® Process.

The 3 main steps in the process are:

  • dissolution of the target plastic using a selective solvent; other components in the waste fraction remain undissolved;
  • separation of contaminants from the recovered polymer solution;
  • precipitation of the target plastic from the purified polymer solution.

If necessary, the main steps are supplemented by upstream crushing and pre-cleaning processes and by downstream conversion involving mechanical concentration, drying and compounding.

This recycling process is currently being tested at the Fraunhofer IVV
on industrial composite materials, e.g. ABS waste containing flame-retardants from the electronics industry and car manufacturing industry, and optimized on a small pilot-plant scale. The aim is to scale up the process to industrial plants for the production of quality-assured recyclates.

In order to be able to survive in the marketplace, the plastic recyclates must possess properties akin to virgin materials. In the process optimization work, the functional property requirements and hence the specifications regarding the type-purity, additive content and aging properties are decisive. The analytical specification of the input fractions provides development targets for the recycling process and base data for the quality control of the recyclate.

We are hence able to offer our customers individual process solutions. Using modern equipment, brominated flame-retardants and their toxic degradation products (polybrominated dioxins and furans) are for example analyzed. This analytical work allows us to evaluate the efficiency of the recycling process, namely product quality versus process costs.