The plastic perspective

Plastic is a part of our everyday lives and going through a day without using plastic in some form is virtually impossible. But this material that is everywhere today made an appearance only a little more than 100 years ago.

The invention

In 1907, Belgian chemist Leo Baekeland pioneered the first fully synthetic plastic Bakelite by combining two chemicals, formaldehyde and phenol, under heat and pressure. In the following decades, advancements in polymer science led to the creation of new types of plastics, including ones specifically designed for packaging, such as polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET).

The process

Plastic is made by extracting monomers from petroleum or natural gas followed by polymerization during which monomers are chemically bonded together to form long chains called polymers. The specific method of polymerization varies depending on the type of plastic being produced. It is then shaped through extrusion, injection molding, or blow molding.

The varied types

There are multiple types of plastics, including very hard materials like polycarbonate and ABS used in the classic LEGO bricks. At SIG, varied types of plastics are used for different packaging and fitment types. Primarily, they are polyethylene with a spectrum of melting temperatures. They range from ethylene vinyl acetate (EVA) used to obtain strong bonds in the thermal lamination process for bag-in-box to high density polyethylene (HDPE) used for its heat resistance properties, applicable for fitments during hot-filling. Non-polyethylene materials used include ethylene vinyl alcohol (EVOH) for oxygen barrier and polyamide (PA) for durability.

Why is it so prevalent 

If we look at food and beverage packaging, plastic can be instrumental in ensuring food safety and shelf stability – without adding to the weight of the pack. Apart from appropriate barrier properties enabling product protection, the lightweight properties of plastic help cut down carbon emissions at every touchpoint, including transportation. Despite its prevalence, managing plastic waste is a top concern. No wonder the industry is moving to flexible packaging with much lower plastic-to-product ratio. The more lightweight flexible packaging provides all the protective properties of plastic using far less material, leading to reduced plastic waste.

End of life: recycle and more

A lot has been said about recycling, and if done properly through effective waste management, it can help combat environmental concerns significantly. Plastic recycling is widely available across the world today with recycled plastics being a popular raw material for many products.

But not all plastics are recyclable, however, that doesn’t mean they cannot be reused. Non-recyclable plastics can be transformed into different types of fuel and energy, through a process called Pyrolysis. Also, Reduce, Reuse, Recycle is the way forward and flexible plastic packaging with its significantly reduced weight and quantity is key to minimizing environmental impact to a certain degree.

In the next part of our series, we will examine the newest packaging material on the block: monomaterial. What does it really mean? And why is being heralded as the next big thing in packaging. You will find the answers in the next edition of Material Matters. Watch this space or just subscribe to our exclusive bi-weekly newsletter and never miss a story on the SIG blog.