WRAP unveils progress on food grade PP
09 November 2010
WRAP’s pioneering work – launched by Paul Davidson, Head of Sector Specialists at WRAP, as Identiplast 2010, the biggest plastics forum in Europe, gets underway – also involves enhancing market opportunities for recycled PP by providing funding, technical expertise and knowledge and working with industry to find solutions to this market.
The widespread use of PP means it is the third most common polymer found in household waste in the UK after high density polyethylene (HDPE) and polyethylene terephthalate (PET). Unlike milk and drink bottles, PP packaging is used in many different grades and colours making it difficult to achieve EFSA (European Food Safety Authority) standards. Coupled with attractive PP export prices, there has been little incentive for industry to consider the benefits of this route to market.
WRAP has taken on the challenge to reduce the dependence on virgin PP in the manufacture of food packaging and, at the same time, divert waste from landfill and boost the UK market for recycled PP.
Working with partners including Greenstar WES and Axion Consulting, the aims of the project to date included:
• Developing a food grade recycling process for polypropylene and test whether the existing food grade High Density Polyethylene (HDPE) recycling process can be used to recycle PP;
• Identifying the technical requirements for a successful food grade recycling process for PP;
• Developing the steps necessary to achieve food grade status; and
• Producing food grade PP products (substituting for virgin polymer).
To date the project has achieved a great deal.
1. Using the existing recycling process for food grade HDPE (PP and HDPE have similar physical properties) it has been possible to clean the PP for use in certain food grade applications but an improved cleaning for lower volatility contaminants is required.
2. The food grade recycled PP can be both thermoformed and injection moulded and therefore is suitable for use in the common PP conversion processes.
3. Work has shown that better label and ink removal is required in order to develop a successful food grade recycling process.
Paul Davidson, Head of Sector Specialists said: “WRAP is committed to working with partners to achieve food grade PP. This has been technically challenging to date but I believe a huge amount has been learned that will benefit the industry going forward. We always knew this project would come up against hurdles, as it has never been attempted before. But the global benefits if we can crack it, and I believe we can, are huge.”
Moving forward with the aim of achieving this grade of PP the next steps will be for WRAP, in partnership with industry, to test alternative technologies to determine if contaminants with low volatility can be removed effectively to extend the range of food grade applications. A viable automated process needs to be developed to sort food contact from non-food contact as hand sorting of food contact is not cost effective.
WRAP is continuing this project in a second stage looking at improving the cleaning efficiency of heavier contaminants and investigating ink removal from used PP packaging. If this can be achieved it will signal a revolution in the reuse of PP, similar to that of PET and HDPE milk bottles a decade ago. Results are due to be published in early spring.
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