PET (polyethylene terephthalate) is a hard and clear polymer material with extremely good mechanical features. It shows excellent tear resistance; it can resist high pressures without breakage; it is used to produce packaging for beverages – PET bottles.
PET material is also suitable for the production of extruded foil. Subsequent biaxial stretching of the foil (in both directions) significantly improves strength in both directions. It is used as a packaging material in gift packs or as baking foil. In foil form, PET is highly resistant to steam and gas permeability, thereby providing protection to the packaged products, while also being resistant to the effects of the oils and fats in the packaged foodstuffs.
PET can be combined with other materials to create multi-layer packaging, the features of which are modified for the specific application – the packaging of aromatic spices, cheese, smoked meat, etc. Upon request, such foils may possess different colours, be imprinted or metal-coated (cosmetics, toothpaste) or laminated (packaging for pet feed).
Typical examples of PET applications include:
Fibres in the textile industry – dressmaking, winter jacket wadding (padding).
Bottles for beverages, in particular for sparkling and alcohol-free liquids.
High-speed boiling pouches, precooked food bags, packaging for non-perishable food.
PET is easily recyclable. PE bottles sorted from municipal waste are frequently reprocessed into fibres.
Aluminium (chemical symbol Al, Latin title Aluminium) is a very light metal of a whitish-grey colour and a very good conductor of electrical current. It is widely employed in electronics and in alloys for aircraft, as well as many other applications.
Aluminium is popular due to its relatively high chemical resistance and low weight. Rolling it into a thin foil results in kitchen foil, which is used in baking and roasting or as a protective packaging material for various applications.
Aluminium is also employed to produce flexible packaging foils. An aluminium layer is usually steamed onto plastic foil by electrical discharge in a vacuum.
PE (polyethylene) is the most widely used plastic in the world. Annual production exceeds 90 million tons. Developed back in 1933, it gave rise to the plastics popular today, which have transformed the way people live. From a chemical perspective, the structure of polyethylene is very simple, so its manufacture is relatively easy and inexpensive. Due to its density, polyethylene is classified as two major types: low-density (LDPE) and high-density (HDPE), while a third type is referred to as linear low-density PE (LLDPE).
Both types of PE are easily processed by plastic-processing technologies, and products of various shapes and sizes can be made. In general, polyethylene has excellent strength, high toughness and ductility; products may be transparent or coloured with pigments. The common methods for processing PE are extrusion (2D products) and injection-moulding (3D products).
Popular uses of polyethylene include:
Flexible packaging – bags for fresh and frozen food products, shopping bags, extensible foils.
Solid packaging – bottles for detergents and cosmetics, canisters, barrels, large-size containers.
Domestic products – kitchen dishes.
Tubes and pipes
Polyethylene may be recycled. It is widely present in communal waste, hence efforts are made to sort (the yellow container for sorted waste) and reuse it.
PP (polypropylene) is the second most frequently used material in Europe, accounting for 20% of plastic consumption. Polypropylene is similar to polyethylene in terms of features and potential applications, hence both polymers are classified as polyolefins. However, in contrast with PE, PP possesses higher strength and consistency. Since its melting temperature is higher, it also shows good temperature stability. The consistency of PP lends good dimensional stability to products.
Polypropylene can be found almost anywhere: in packaging materials, household appliances, clothing, means of transport and many other places. More than half of the world’s PP production is given over to packaging. It is also used in technical applications.
It is used in the production of:
Packaging – flexible foils, pots for dairy products and beverage machines, moulded trays, lids/caps for packaging and bottles, bags, notebook covers.