Why multilayered plastic structures are indispensable

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multilayered plastic structures

In the last issue, we wrote about why multilayered plastic structures cannot be done away with and why banning them is just not going to work. I think we need to reiterate some of the major considerations and go deeper into the points made in our previous article.

Let us start with a few basic truths that simply cannot be overlooked –
The Indian market or supply chain has ambient temperatures ranging from sub-zero levels to highs of up to or even beyond 50 degrees Celsius and relative humidities touching 100%. Moisture and gas transmission rates of moisture and gases through packaging materials/systems go up substantially with increased temperatures and humidity levels.

Being a large country with high transit times, extensive distribution, primitive warehousing in many rural markets and long storage times on retail shelves, we require fairly long shelf-lives for most packaged products. In some cases, these go up to more than 12 months. This shelf-life has to be delivered primarily by the packaging materials.

All this means that most products need medium to high moisture and gas barrier requirements to be met, something that just cannot be delivered cost-effectively by single polymer solutions. In fact, high barrier requirements can only be effectively delivered by aluminum foils or metallized oriented films.
Multilayered structures, especially those that incorporate dissimilar materials or multiple polymers, are notoriously difficult to separate into discrete layers that can be effectively recycled. Industry has been working for over 50 years in trying to develop suitable technologies and/or processes for this but nothing looks even remotely commercially viable.

Almost all packaging has to be printed or decorated and this makes the job even more complicated for flexible structures. (Even a naturally recyclable material like paper/board has serious compatibility problems with direct contact with food or sensitive products because of traces of retained toxic mineral oils from printing inks in recycled paper/board.)

Metallizing plays another important role apart from providing high levels of moisture and gas barrier. Many applications like packaging of snack foods, fried foods and high-fat biscuits require almost total light barrier (metallizing with an optical density of 2.3 or more) to prevent oxidative rancidity from taking place. It is light that triggers the oxidation of fats and exclusion of light significantly extends shelf-life. Metallized films also provide opacity and non-transparency that many packaging applications require.

Flexible packaging systems are far and away the most cost-effective and sustainable solutions available for almost all packaging applications because of input resource optimization, lightest weight, carbon footprint and lowest transportation and distribution costs. All this means that flexible multilayered structures make for the minimum use of materials obtained from non-renewable resources, reserves of which are finite and relatively ‘limited.’

Single polymer solutions offer very limited shelf-life. The only two major packaging applications that use single polymer films (LDPE) are milk and bread packaging. Here, the film offers only something like a week’s shelf-life in ambient storage conditions (although this is all that these products are looking for). Some amount of sealable BOPP films are also used but these quantities are relatively small and they are not suitable for many sensitive products.

Conflict of options
No decision can be taken on any packaging without studying the system in its entirety across its full life cycle. As with any system, there are always going to be multiple choices on system components and clear conflict between system choices. This is why a score-card approach is necessary and we need to do what is called a Life Cycle Analysis (LCA) and arrive at a final bottom line on environmental and sustainability impact. While recyclability does constitute an important consideration, and this clearly goes against multilayered plastic structures, the simple fact is that flexibles score very high on net impact compared to rigid and semi-rigid systems (such as cans, bottles, cartons and the like). The issue of resource consumption is a vital consideration and over-rides all other factors.

Conservation of resources
Let us now look at what impact this has. The question is how best to extend the finite reserves of non-renewable resources (such as crude oil, coal, minerals, natural gas) so that we do not run out of these resources in the short to medium term. The uncomfortable truth is that the question is when and not if these resources are going to dry up. This inevitable outcome is going to happen sooner or later and all our efforts have to focus on how much longer we can stave this off.

Let us assume that flexibles, because of the problems in being effectively recycled, can be replaced by single polymer solutions or by rigid packaging systems like cans or bottles. We know that, in this case, the quantum of input resources and materials could go up by as much as 10 times and that the package costs will go up by about 4 or 5 times compared to flexible packaging options. In addition to this, carbon footprint will also go up quite significantly. Therefore, what this means is that our initial material consumption itself will go up ten times and, in most cases, these materials are sourced from non-renewable resources anyway. Thus, what we are doing is depleting the finite reserves of non-renewable resources ten times as fast and advancing the ‘doomsday’ by several millennia. Added to this is the considerably higher carbon footprint and negative impact on the environment. A simple analysis of the scorecard (LCA) will tell us how crazy this is. In net terms, it is much better to accept that we will fore-go the benefits of recyclability given that we gain so much in terms of resource consumption and conservation. In any case, recyclability has constraints on where the recycled input materials can be used for equivalent prime applications.

Is it right for us to opt for alternatives to multilayered plastic structures simply for the sake of recyclability? Most certainly not, given the consequential impact on material resource consumption, extension of resources of non-renewable resources, degradation of the environment and, most significantly, much higher packaging costs. The answer lies not in the banning of multilayered plastics but in focusing efforts on recovery of materials from mixed polymer formulations and in finding new applications from the recovered and or regenerated input materials.

Consequences of a ban
The proposed ban will seriously hurt not only brand owners and the packaging industry but also end-consumers and the man-in-the-street. The economy will come to a grinding halt. If the increased packaging costs are passed on by the brand owners, the resultant effect on wholesale inflation will be several percent. In the flexible packaging industry, the largest two or three companies may carry on for a while as they have some international business and industrial applications to fall back on but more than 90% of the industry will be simply wiped out. Is this what we want to see?

Conclusion
It is time that the government and the powers that be wake up to these realities and not blindly follow impractical road-maps towards circular economies without taking into account all the resultant problems that could crop up. I sincerely hope that good sense will prevail and we will not take dire steps simply for patently impractical ideological reasons.

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