PET or PVC as preferred Material for Plastic Cards?
A Comparison of the two Ecoprofiles, based on Life Cycle Analysis (LCA)
From cradle to grave, the complete life cycle (LC) can be divided into three main segments:
- Production phase
- Use phase
- Disposal phase
1. Production Phase
The important criterion to characterize this phase is primary energy demand. According to BUWAL SRU 250 «Life Cycle Inventories for Packagings» and SRU 300 «Evaluation of Life Cycle inventories for Packagings», worldwide recognized as the most comprehensive and up-to-date LCA data collections and assessment methodologies, the primary energy demand is as follows:
PET 83.8 MJ/kg (margins: 66.. 98 MJ/kg;
PVC 66.8 MJ/kg (margins: 48.. 89 MJ/kg)
Compared to PET, production of PVC demands 20% less primary energy. Furthermore, PVC is only partially made from fossil resources, the rest being inorganic. However, this latter is chlorine, which is very controversially discussed; not only by Greenpeace, WWF and similar ecology-oriented Non-Governmental Organizations (NGO), but also by clearly industry-oriented groups and think tanks.
Conclusion regarding an intermediate ranking in the production phase:
2. Use Phase
The important criterion to characterize this phase is convenience. And in this respect, both materials are equally well suited to fulfill all the convenience demands
However: A short use phase covering only a small time span favours materials with a short ecological payback period like PET. This is, among others, a reason why such rnaterials are to be preferred to consumer product applications; whereas PVC, requiring a longer ecological payback period, is better suited for tong-term applications typically found in investment goods.
Conclusion regarding an intermediate ranking in the use phase~
1st and 2nd PET and PVC
3. Disposal Phase
The important criterion to characterize this phase is environmentally sound disposal processing. In most OECD countries - already common in the Western European countries - thermal processing through incineration is primordial disposal process.
The three main purpose are: first to convert the reactive municipal waste into harmless inert materials; second, to achieve volume reduction; third, to safe primary
Energy carries (e.g. fuels) used for heat production through replacing them by burning waste and using the produced heat, thus protecting fossil resources.
Therefore, the ecological behavior of PET and PVC during incineration is the question to be regarded.
Burning PET in Municipal Solid Waste Incineration (MSWI) plants does not cause any ecological problems.
Not so with PVC: In most cases, burning PVC in MSWI plants may produce and release dioxins. And these substances are very toxic, thus requiring a very sophisticated handling. For good reasons, in Western European countries as well as in most civil societies, dioxins are politically not accepted and socially completely refused. Thus, contributing to production and release of dioxins is a very significant
and disadvantage of PVC. Furthermore, burning PVC produces hydrochloric acid (HCl), of course. HCl is loss toxic than dioxins. Depending on the MSWI plants pollution abatement equipment, HCI may afterwards yet be released, thus contribute to the generation of acid rain which is a serious ecological concern.
The material-based recycling is an alternative, and here both polymers enable technically equally good recycling options. However, the market capacity to absorb the mass of goods made of so-called secondary raw materials(e.g. recycled material) is rather limited for products made of recycled PVC, and is broader for products made of recycled PET. This reason is the difference in market capacity for investment and for consumer good: PVC is more suitable for long-life products (because only here PVC can reasonably carry its environmental burden over time);
PET is more suitable for short-life products.
Conclusion regarding an intermediate ranking in the disposal phase:
1st PET with many pros
2nd PVC with many cons
4. Overall Assessment
Combining the three intermediate rankings to a final ranking by assessing their pros and cons gives the following result:
Taking LCA as a powerful tool, PVC shows more dark than sunny sides as a material for plastic cards which is a typical consumer application used in large and rapidly increasing quantities. For such a short-life mass product it is PET which is the material to be chosen and to be widely used.