MECHANICAL RECYCLING

- Overview - Open loop - Close loop

Overview

EBFRIP promotes the adoption of a flexible approach to BFR-plastics waste management, encompassing an optimal balance of technical, environmental, economic and regional market factors, ensuring that natural resources are used wisely and efficiently. E&E equipment uses many different types of plastics, designed with special properties for producing high-specification products as efficiently as possible. To mechanically recycle post-user plastics waste, it has to be collected, sorted, separated, ground, washed and reprocessed before it can be mixed with virgin plastics of the same type for molding new products, or used on its own for alternative lower value products. The availability of consistent waste streams with known characteristics is thus a key criterion for successful recycling. Only in a limited number of cases are the overall plastics recycling operation economically viable because of the relatively low cost of new, virgin plastics [Plastics Europe (2003): Plastics - An analysis of plastic consumption and recovery in Europe.- 20 pages, Brussels].

Practical experience shows that for material recycling to be viable, there must be homogenous plastics and a large constant waste stream. The markets for recycled plastics are limited due to technical feasibility and economics. Small impurities from different plastics or other materials can easily occur during the recycling processes and drastically decrease the electrical and mechanical performance or safety of recycled plastics. Virgin plastics are usually cheaper and always of higher quality than recycled plastics after collection, dismantling, sorting and remelting [Plastics Europe (2003): Plastics - An analysis of plastic consumption and recovery in Europe.- 20 pages, Brussels].

Due to the ban on PentaBDE and OctaBDE since August 2004 and PBBs since 2006, BSEF does not promote mechanical recycling of historic plastics containing BFRs from open loop waste streams. However, recycling within a closed loop system, where the E&E manufacturer gets back its own equipment, might be a completely different case in terms of offering practical opportunities for the mechanical recycling of WEEE plastics containg BFRs.

Click here to read the paper "WEEE plastics with brominated flame retardants - from legislation to separate treatment"

Open Loop     Studies of interest:

• “Comparison of the recyclability of flame-retarded plastics”; Environ Sci Technol. 2003 Feb 1;37(3):652-6; Imai T, Hamm S, Rothenbacher KP. Techno Polymer Co., Ltd., 100 Kawajiri-cho, Yokkaichi, Mie 510-0871, Japan
  
  
  • ABS Plastics containing BFRs proved to be the most suited to mechanical recycling. Indeed, “the tested BFR containing plastic materials showed superior recycling properties compared to the tested halogen-free plastic grades” as they were able to retain important properties such as colour and fire safety rating. Also none of the materials tested showed potential to form dioxins and furans, thus fully respecting even the strictest environmental limits set by the German Dioxin Decree.
    
    
• “Determination of Polybrominated Diphenyl Ethers and PBDD/Fs during the Recycling of High Impact Polystyrene Containing Decabromodiphenylether and Antimony Oxide”. Chemosphere, 44/6 (2001) 1353-1360 Hamm, S.,Strikkeling, M.,Ranken, P.,Rothenbacher, K.P, 2001.
  
  
  • High impact polystyrene (HIPS) plastic containing Deca-BDE and antimony oxide was recycled 5 times. The study showed that even after the material was recycled five times no debromination of Deca-BDE into lower brominated diphenyl ethers takes place. Furthermore the 5 times recycled product was fully compatible with the German legislation on dioxin/furans limits in products.
    
    
• “Workplace measurements for PBDF/Ds during recycling of HIPS/Sb2O3/DecaBDPO plastic at an extruder at the Technical University of Erlangen-Nuernberg”; Workplace assessment, GfA Gesellschaft fuer Arbeitsplatz- und Umweltanalytik mbH Report No. 60425-002 B01. Kieper, H., 2000.
  
  
• “Workplace measurements for PBDF/Ds during recycling of HIPS/Sb2O3/DecaBDPO plastic at an injection molding machine at the Technical University of Erlangen-Nuernberg”; Workplace assessment, GfA Gesellschaft fuer Arbeitsplatz- und Umweltanalytik mbH Report No. 60425-002 B01, 2000.
  
  
  • In a pilot project, HIPS/Deca-BDE plastic was recycled by grinding, extruding and injection molding. Workplace exposure at the extrusion and the injection molding work place was monitored and found to comply with the strict German legislation on dioxin/furans limits in workplace air.
    
    
• “TV case study, a life cycle analysis”, SP TV LCA data. Simonson, M., Blomqvist, P., Boldizar, A., Moeller, K., Rosell, L., Tullin, C., Stripple, H., Sundqvist, J.O. Fire-LCA model, 2000. Interscience Communication Ltd., London,
  ISBN 91-7848-811-7.
  
  
  • The study demonstrated full compliance with fire safety standards after aged material was recycled and concluded that HIPS plastics containing Deca-BDE carry better physical properties than plastics without BFRs.
    

Close loop

Producers may decide that they wish to set up a "closed loop" system to ensure their products are returned to them and then carry out the necessary treatment, recycling and recovery of their products themselves.

Source: Ricoh Presentation to BSEF Tokyo Seminar, November 6, 1998

The electrical appliance in the photo below may look like an ordinary state-of-the-art photocopier. However, unlike other photocopiers, 30% of its outer plastics housing is made of recycled plastic containing BFRs. This copier was launched in the Japanese market in Spring 2000.

Photocopier with 30% of recycled plastic (Ricoh, Japan).

The plastic used in this copier is particularly suited to recycling. ABS requires brominated flame retardants to be added in order to meet the high fire safety standards of UL 5VA and 5VB. Copier manufacturers and their plastics suppliers have found that certain ABS/BFR combinations (in this case brominated epoxies or oligomers) have clear advantages in terms of recyclability. This is basically down to the stability of the brominated flame retardants in the recycling process. For instance, only with the ABS/BFR plastic does the flame retardancy of the polymer maintain the UL 5VA level, thus foregoing the need to add more flame retardants after recycling. This provides clear economic as well as environmental benefits.