Recfinmix

Primary Recycling of Polyolefin-Mixed Films for High-Added Value Applications in the Blow Moulding Industry

At the moment about 1.5 million tonnes of plastic are being recycled yearly, 75% of which is polyethylene, both low density (LDPE) and high density (HDPE). Recycling of plastic film so far one is of the weakest points in all recycling schemes. The reason for this failure is that post-consumer plastic film waste is usually a mixture of diverse plastics, especially LDPE, HDPE and polypropylene (PP), together comprising 95% of the total fi lm. Although cleaning and separation of the polyolefi ns (LDPE, HDPE and PP) from the rest is easy using flotation or hydrocycloning methods, separation of LDPE, HDPE and PP from each other is difficult, since their respective densities are very similar while their variable shape do not allow the use of automated, sensor-based methods (such as use of near-infrared detection).

The overall objectives of the Recfi nmix project were both ambitious and strategic for the SME partners involved in view of the current and foreseeable market trends. The three key objectives of the project were:

• To develop a method for separation of mixed post-consumer polyolefin film waste, with an average composition of 71.4% LDPE, 17.5% HDPE and 11.1% PP into a high added-value LDPE stream suitable for production of blown film and with less than 5% HDPE and PP impurities, and a low value HDPE-PP stream with less than 20% LDPE impurities, suitable only for injection moulding, therefore recovering more than 90% of the original LDPE for high added-value applications.
• To construct a suitable semi-industrial pilot separator for mixed polyolefin film wastes based on the principle described, capable of fulfilling the purity targets set and with a production capacity in the range of 100-200 kg/hour. Optimisation of the construction and processing parameters of the referred prototype separator will allow for the design of an industrial separator in the range of 1000 kg/hour, suitable for the medium and medium-small companies which are characteristic of the plastic recycling sector, and with an affordable price range of €200,000.
• To demonstrate the validity of the technologies developed by the trouble-free production, especially regarding processing bubble integrity, of 50 to 250 micron blown film using exclusively the purified LDPE material obtained from mixed waste polyolefin films. Although the validity of the method would be demonstrated using 100% recyclates, films using mixtures of recycled and virgin LDPE were also produced.

The consortium comprised six small to medium sized enterprises (SMEs) and three research organisations from five different EU countries, and covered all the steps regarding separation and recycling to obtain LDPE suitable for production of blown film from waste polyolefin film mixtures and the development of equipment for such a purpose.

The SME core group comprised companies in the field of production of lines for plastic recycling (Rondol Technology), manufacture of efficient industrial heat systems (Zaber), production of recycling equipment to be integrated as a secondary stage including cen trifuges, vibrational sieves and other devices (GTV), plastic recycling (PHB), plastic compounding (Perplastic) and production of blown LDPE film, also including some recycled grades (Rinaplas).

Organisational Information

Budget: €1M
Funding: €635k
Start Date: September 2006
Finish Date: December 2008
Duration (in months): 28
Lead Partner (Co-ordinator): Fundación L’Urederra, Spain

Participants

• GTV, Lithuania
• Perplastic 2 SL, Spain
• PHB, Netherlands
• Rinaplast SL, Spain
• Rondol Technology, UK
• Smithers Rapra, UK
• University of Zielona Gora, Poland
• Dr ZABER SP, Poland

Results – What happened next?

The project made good progress towards its stated objectives during its lifetime and all of the partners benefited in a number of technical and commercial ways from being in the consortium. A prototype recycling system for the separation of mixed polyolefin film waste was constructed and trialled during the project and this showed considerable promise in achieving the target of separating LDPE film from PP and HDPE film. This development provided the SME partners with a useful platform with which they could continue to work towards the full exploitation of the technology in the future.