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21 October 2022

Polyethylene: characteristics and areas of us

Everything you need to know about polyethylene for packaging

Polyethylene (PE) is one of the most common and widely used plastics for the production of everyday objects, packaging and wrapping. Thanks to its special properties and extreme versality, it can be used to make various types of packaging, from the thinnest, such as bags, plastic films or food films, to the most rigidm such as containers, bottles and jars.

Among the characteristics that make it one of the preferred plastics in the packaging sector are its elasticity and flexibility and its resistance to impact, wear, water and low temperatures. Due to its non-toxic and hygienic properties, it is also widely used in the food industry.

But what, specifically, are the characteristics of polyethylene and its main areas of use? Let's fidn out together! 

What is polyethylene: definition and types

Polyethylene is a thermoplastic materal in the form of synthetic polymers with a high particle density. It is created through the polymerisation of ethylene, a special process in which small particles, called monomers, are combined. The structure of polyethylene is quite simple: it is composed of carbon and hydrogen. It presents itself as a while solid with excellent insulating properties and chemical stability. Depending on the molecular weight distribution and branching, various types of polyethylene can be obtained, with different characteristics and uses. Among those most commonly used are:

  • High-Density Polyethylene (HDPE) a thermoplastic polymer derived from petroleum, containing carbon and hydrogen. This type of polyethylene is composed of linear chains and therefore has greater strengh and rigidity. It is visually more opaque, but can withstand high temperatures (110°C continuosly and 120°C for short periods). Due to these characteristics, HDPE is often used for the production of packaging such as cans, bottles and rigid containers;
  • Low-Density Polyethylene (LDPE), also a thermoplastic polymer derived from petroleum, which differs from HDPE, however, in that it is composed of polymer chains with branching. This makes it a lighter, more ductile and flexible material and therefore ideal for the production of films, bags and pouches used for packaging. Made in translucent or opaque varieties, it is nonetheless quite resistant and also has excellent water resistance. It can also withstand temperatures of 80°C (95°C for short periods).

How does polyethylene come into being?

Today, polyethylene is one of the most widely used and popular plastics, but its invention was pure chance. it was in fact invented more than 100 years ago, in 1898 to be precise, by a German researcher, Hans von Pechmann, who accidentally obtained a low molecular weight polymer with a structure equivalent to polyethylene. In 1933, the first synthesis for large-scale production procedure was refined two years later by another chemist, Michel Perrin, who understood how to reproduce it at will, so as to mould the material.

This enabled Imperial Chemical Industries to design the first pilot plant for large-scale production and in 1939, commercial production of the raw material began in Northwich, which completely revolutionised the market within a few years. From then on, polyethylene began to sperad and to be increasingly used for packaging and most consumer products: from household items to bags, from bottles to food films, to pipes and car parts.

Difference between polyethylene and polypropylene

Polyethylene and polypropylene (PP) are two plastics that might appear similar at first glance. Polypropylene is in fact another thermoplastic material that is widely used to make packaging and everyday objects, but it differs from polyethylene in a number of key aspects, including:

  • colour and weight: polypropylene is a translucent white material, lighter than polyethylene, but less transparent. Polyethylene is in fact colourless and allows for quality results in terms of tear resistance and transparency, especially for the production of packaging;
  • resistance: polypropylene can withstand higher temperatures (between 140° and 170°), while polyethylene is more resistant to low temperatures and retains its characteristics between -80° and 80°;
  • flexibility, which determins the elasticity of the plastic material. In this case, polyethylene is clearly superior to PP in terms of elasticity and elasticity and elongation capacity;
  • recycling process: the two materials obviously have different recycling codes, but both can be easily recycled and, if subjected to thermal processes, can be repeatedly shaped into new products. Due to its special characteristics, however, the recycling possibilities of polyethylene are greater.

Polyethylene: main areas of use

Thanks to its properties and fact that it can be produced cost-effectively, polyethylene is used for a wide range of applications and in numerous industrial sectors for the production of everyday items, packaging and cases used in everyday life. The main uses of polyethylene, whether high or low density, include, among others:

Polyethylene for packaging: the polyethylene articles offered by Plastisac

Polyethylene has always been one of the most widely used plastics by Plastisac for the production of packaging and packaging solutions for food and non-food products in numerous industrial sectors. Plastisac offers a wide range of polyethylene packaging for the food sector, safe and certified for contact with foodstuffs: from reel films for machine or manual use to bags and pouches useful in various stages of processing in the food industry. Plastisac also offers various possibilities for customising polyethylene packaging, for example with:

  • customised prints and campony logos;
  • various additives mixed with the raw polymer during production, to improve the products depending on the final application;
  • customised colours;
  • perforations designed according to the intended use.

The company has always been committed to promoting polyethylene recycling and developing environmentally friendly solutions. The polyethylene that arrives is controlled thanks to a precise identification code that makes it possible to know the entire path taken by the material, from production to the moment of delivery, and thus to guarantee the complete traceability and quality of each package produced. Furthermore, all plastic residues produced during the processing phases are collected and reused in the production cycle as secondary raw material for the manufacture of new products. This allows Plastisac to maintain high production standards and work contantly to produce increasingly green and eco-sustainable packaging.

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