Why has PET become the gold standard in bottle production?

Polyethylene terephthalate, commonly known as PET, is a plastic that has entered our everyday life for good. Discovered in the 1950s, it was initially used exclusively for the production of films but continuous research and technological advances have since significantly expanded its range of applications. First of all, smooth, lightweight and unbreakable bottles began to be designed, which quickly gained an advantage over glass and dominated the packaging market as early as in the 1970s. In this paper we will try to explain why PET has become the gold standard in bottle production and what is the miracle behind this material is. Have a good read!

A brief analysis of PET properties

PET as a material for making bottles for both food products and household chemicals owes its success, among other things, to the material’s physical and chemical properties. Here are some of them:

Transparency and appearance – these properties allow for an attractive presentation of products, which is extremely important in the food industry. The customer can freely assess the consistency and colour of the product, which may indicate freshness and thus influence purchasing decisions.

• Strength and durability – PET is highly resistant to mechanical damage and does not break, unlike glass. It is therefore safer to use.
• Chemical resistance – polyethylene terephthalate is physiologically neutral and resistant to substances such as diluted acids or oils. This feature makes it an ideal material for holding food, cosmetics and household chemicals.
• Flexibility and dyeability – PET can be easily formed in the production process, allowing bottles with customized shapes to be created. Also, the material offers a high ability to be dyed, which opens up new possibilities in the design of visually attractive packaging.
• Recycling and sustainability – PET is a fully recyclable material, making it environmentally friendly. Importantly, the recycling process can be repeated several times without losing the quality of products made from the recovered raw material.

PET applications in the packaging industry

PET packaging is widely used in various sectors of the food, cosmetics, pharmaceutical and chemical industries. PET bottles are commonly used for packaging drinks, juices, mineral waters, oils, sauces, milk and kefir, cosmetics, medicines, detergents and many other products. With its unique properties, the material has become the gold standard in packaging production, ensuring safety, attractive looks and environmental friendliness.

Advantages of PET over glass

• Owing to these numerous advantages, PET bottles quickly gained popularity and became the dominant solution in the packaging industry, replacing traditional glass packaging in many applications. The decisive factors included the following:
• Lower processing temperature – PET can be formed at temperatures as low as 180 degrees Celsius, while glass requires around 1,700 degrees Celsius. This means significantly lower energy consumption and lower greenhouse gas emissions during the production of PET packaging.
• Less weight – PET packaging is much lighter than glass packaging, which provides for ease of transport and reduces logistics costs, making it more environmentally friendly. Lightweight PET bottles are also more convenient for consumers to use.
• Greater resistance to damage – PET material is highly resistant to mechanical damage, unlike glass, which breaks. This reduces the risk of waste during production and transport due to damage to packaging.
• Renewability of raw materials – apart from recovering PET from recycling, primary raw materials for its production can be at least partially obtained from renewable plant-based materials (BIO-PET).
• Better developed recycling process – the PET recycling process was the first to be legally regulated by the European Union. That regulation enabled its dynamic development and has made it the most technically advanced system to-date for recovering plastics while respecting the natural environment.

A variant of PET bottle production

It is worth taking a closer look at one of the technological variants of PET bottle production, which is much simpler than the production of glass bottles and allows for obtaining packaging with the desired shapes and properties. The process consists of several steps:

• Preform making – the first step is to produce preforms, which are injection moulded for precise control of the dimensions and wall thickness.
• Bottle blowing – the preforms are then heated and blown in moulds, taking the desired bottle shape. This step requires specialized equipment and precise control of temperature and pressure to ensure uniform bottle quality and strength.
• Cooling and stabilization – after blowing, the bottles are cooled and stabilized to obtain their final form and mechanical properties.
• Labelling and packaging – finally, the bottles are labelled and then packed for transportation and distribution.

Barrier additives may also be added at the PET bottle production stage. Their purpose is to extend the freshness of products, protect the contents from the influence of external factors and reduce the risk of packaging components leaching into the product.