Green in the true sense

The continuing debate about packaging and the environment seems to have taken on even greater impetus in recent months. The renewed focus on the environmental impact of every aspect of our daily lives has inevitably led to the spotlight falling strongly onto the packaging industry. Retailers in particular are keen to be seen to be taking positive steps in this area.

However, delivering a positive environmental image takes more than selecting one material over another. Recent research by the Waste & Resources Action Programme (WRAP) has revealed that households in the UK throw away 6.7mn tonne of food every year – around a third of all the food we buy. Think how much higher this might be without effective packaging to provide extended preservation. That is the sort of benefit that it is not very often factored into a pack’s environmental profile.

Also, retailer research in America has found that in-store wastage of grapes sold loose can be more than 5 per cent. This can be cut by 0.5 per cent if they are sold in bags. If in enclosed punnets, wastage falls to 1.5 per cent. Similarly, wrapping cucumbers and other produce in plastics film can add five days to shelf lives. In this context, these types of packs, which are often cited as being examples of ‘excessive’ packaging, are actually shown to perform a valuable role.

What all this highlights is the importance of function in the design and manufacture of any pack. Environmental benefits and improvements should be implemented wherever possible, but it is essential that they are not undertaken at the expense of the overall purpose of the pack. If it cannot deliver on its basic requirements such as promotion, protection and preservation, then there is little point in its development.

This is not meant to denigrate any new material or manufacturing technique that have been introduced to help reduce the environmental impact of packaging. These are all important initiatives, but no material or process, however environmentally friendly, can provide a solution for every packaging requirement.

For example, PLA, the biodegradable material made from maize or similar crop types, is often portrayed as the ideal ‘green’ plastics. Several of RPC’s thermoforming operations are now able to offer the material, although currently demand is outstripping supply. However, while suitable for the production of thermoformed packs, it cannot deliver the required performance for injection moulded containers.

In terms of recycling, plastics have made great strides over the past 20 years. The proliferation of consumer collection schemes and establishment of reprocessing plants have led to the introduction of packs incorporating post-consumer recyclate (PCR).

Currently, the best opportunities are with post-consumer PET, and RPC is already incorporating this into juice bottles and jars. The PCR process uses 25-40 per cent of the energy resource of the prime polymer, an actual energy saving of approximately 70 per cent.

Nevertheless, we again have to consider what is fit for purpose with this material. For example, since PET is not recommended for injection moulded thin wall packaging, any desire to include PCR material in this type of pack would require too many unacceptable compromises. New tooling would be needed, while pack designs would have to be simpler and the wall sections would need to double, increasing the weight of the container by as much as 260 per cent. Other elements of the pack’s functionality would also be restricted, since injection moulded PET does not lend itself to a peelable lid and the pack would not be microwavable.

On the other hand, polypropylene PCR is unlikely to be of sufficient quality for packaging applications, mainly due to the problems of consumer identification when recycling and the wide span of grades currently used. One alternative RPC Blackburn has come up with is to find a source for post-industrial recycled material, in this case PP mould shells used for contact lens manufacture. This is of high enough quality to be used in food contact applications.

This example demonstrates how the plastics industry is constantly looking at ways to develop and introduce packaging that takes into account environmental concerns and delivers genuine benefits.

Perhaps the best example of this is the lightweighting of packs. Our latest generation of tamper evident small pots are around 5 per cent lighter. With energy used in manufacture and transportation being major contributors to a pack’s overall carbon footprint, this type of improvement offers a real environmental benefit.

The most significant aspect of any lightweighting initiative, however, is that the pack continues to perform properly – this has to be the driving factor. The critical consideration each time has to be its suitability for individual products and applications. Any ‘green’ benefits must complement and not replace this.

Sean Dyer is general sales manager, RPC Containers Blackburn