PET bottles are one of the most popular types of packaging - they have been used in the food industry since the 1940s. Nothing strange about that. PET is light and durable, resistant to acids, fats and derivatives. What other advantages does it have? How is a PET bottle produced? Is PET packaging safe? Please read the article.
PET - what should we know?
Polyethylene terephthalate, commonly known as PET, is a polymer, or more precisely, a thermoplastic polymer. It is characterised by high mechanical strength, abrasion resistance and dimensional stability.
PET is widely used in the food industry, although initially the material was also used in the textile and photographic industries.
PET – easy-to-recycle material
There are many myths about PET bottles and they are quite popular. First of all, it is believed that the use of PET on a large scale contributes to environmental pollution as well as harmful for animal and people.
However, it is worth noting that any packaging that is not recycled is considered to be a pollutant. Moreover, the production of packaging itself is a burden for the environment because it involves the use of its resources, water, energy, emission of pollutants and wastewater.
Ecological packaging is the type of packaging the production of which does not burden the environment excessively and the product is easy to recycle. Looking at PET bottles from that perspective, it is difficult not to notice the above-mentioned advantages. The problem of polluted natural environment is largely related not to the amount of PET but to the way the used bottles are managed. Interestingly, it was proved that the amount of glass and paper that is thrown away is practically the same as that of plastic products.
Paper can only be recycled up to 5 times while PET can be recycled many times. Furthermore, the use of paper as packaging contributes to increasing deforestation so whether the material is an ecological solution is debatable.
Glass packaging can also be recycled multiple times but glass bottles are rarely used for that purpose. Refilling bottles requires a very large amount of water to clean them and, as a result, harmful wastewater is generated. Moreover, the above involves the necessity to transport empty bottles which means additional costs and additional CO2 emissions... On the other hand, it is possible to recycle glass however it is an extremely expensive and energy-consuming process –the melting point of glass is 1200-1300 °C.
It is much easier to recycle PET bottles and the procedure is less harmful to the natural environment. During the process of recycling, the bottles are cleaned and then ground. Then, the so-called regranulate is generated which can be used to manufacture plastic items or bottles. PET bottles are produced with the use of special blow moulding machines and a semi-finished product called PET preform. Preforms are usually manufactured in the process of injection moulding in specialised factories. At that stage, it is possible to use regranulate as raw material for injection moulding to produce new preforms which are then processed into bottles. The melting point of PET is only approximately 300 °C and it is more than four times lower than the melting point of glass. Preforms can be made even from 100% recycled material. Whether the producer uses virgin material (i.e. pure granulate obtained directly from crude oil) or recycled regranulate depends on the price and profitability of the production. Through public education and the implementation of tax incentives to promote recycling, it is easy to encourage manufacturers of preforms and bottles to use PET regranulate.
PET bottles do not pose a threat to the environment if they are collected, sorted out and processed. If people begin to notice the value of PET bottles, the product will no longer be unnecessary waste.
Many countries implement a special recycling system of such bottles which is extremely beneficial for society and the environment. In Germany, reverse vending machines for collecting bottles are placed at the entrance to large supermarkets and grocery stores. The machines count the bottles that are thrown inside them and issue vouchers of a certain value. The system is a great way to encourage people to collect and recycle single-use PET bottles. It is estimated that nearly 90% of PET bottles are recycled in Germany.
PET production - Are PET Bottles Safe to the environment or not?
A standard 500ml bottle weighs only 25g. To compare, a glass bottle of the same capacity weighs approximately 500g and is five times heavier than PET packaging. The weight of packaging has a direct impact on the transportation cost of the product and environmental pollution - the emission of exhaust gases into the atmosphere is significantly increased during transportation.
However, that is not the only problem. The process of production of glass requires much more energy and water. PET bottles are produced with the use of the so-called blow moulding machines in the process of processing a semi-finished product, i.e. preform. Preform is heated in a furnace of a blow moulding machine to a temperature of 60-120 °C and bottles are formed. Glass is blown at a temperature of 1200-1300 °C. The production of heavy glass bottles contributes to emitting significantly more greenhouse gases than the production of light PET bottles, therefore, while using light PET bottles a much smaller carbon footprint is generated.
Scientists from Southampton came to similar conclusions. The researchers compared several types of beverage packaging which was made of various types of material in terms of environmental friendliness. The results of the research, according to which glass bottles turned out to be most harmful to the environment, were very surprising to many people. Interestingly, bottles are the most commonly thrown away type of packaging after a single use.
A PET bottle as well as the process of production of PET packaging can be harmless to the environment. It should be remembered that no other materials are used in the process of forming plastic bottles, which makes the bottles much easier to recycle. Popular cardboard packaging for juices or milk consists of permanently joined layers such as paper, aluminum foil and plastic - polythene. Such packaging enables safe packing of a product and contributes to its durability but it is difficult to recycle because cardboard consists of different types of material. The recently introduced changes in the EU legislation are to encourage food producers to pack their products in easy-recyclable packaging – i.e. packaging made of homogeneous materials, easy to segregate.
Are PET Bottles Safe to people?
Do you know what BPA is? Bisphenol A (BPA) is one of the most common organic chemicals that disrupt the hormone balance. Bisphenol A is very harmful to human health. It causes health problems and contributes to the pathogenesis of many types of cancer.
Bisphenol A is a chemical compound used in the process of manufacture of certain plastic products and epoxy resins.
Hence, it is worth knowing that PET is safe plastic because it does not contain BPA. So, what should we avoid? The largest amount of bisphenol is found in the inner coating of metal cans for food storage, in plastic bottles and containers made of PVC (polyvinyl chloride), PC (and others – polycarbonate), PS (polystyrene), CDs and DVDs.
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