From food to beauty, water to beer, it is pretty obvious that our lives are inundated with plastic packaging.
Plastic made its debut nearly 150 years ago and has since come a long way (which is good news for us because the original plastic “recipe” could cause explosions if mishandled…eek!).
Throughout world wars, color TVs and poodle skirts, the use and durability of plastic for daily goods has steadily increased.
In 1975, the first disposable plastic soda bottle was introduced.
By 1980, refillable glass beverage bottles were all but replaced by plastic throwaways.
As a metrology solutions company, one of our areas of focus surrounds challenges in measuring and inspecting plastic containers; especially when it comes to multi-layer structures. But how are things like plastic bottles, lunch boxes and gas cans produced in the first place?
Injection molding made its first appearance onto the plastic manufacturing scene in the early 20th century (circa 1930ish) and drastically transformed the way plastic containers were produced.
Injection molding is still utilized for manufacturing plastics today but with a little twist – injection blow molding is now commonly used. Basically, it consists of blowing compressed air into a warmed preform – the pre-blown form of a bottle or container (picture a test tube with a screw top!) – to expand it against a cold mold to achieve the desired final shape. The above video gives you an artsy idea of what this process looks like.
Another common method when it comes to plastic container manufacturing is referred to as extrusion blow molding (EBM). The EBM process involves heated plastic (sort of a honey-like consistency) being poured into a mold cavity and then – using compressed air – blown to conform to the mold walls. The video to the right shows the manufacturing process of a gas can using EBM.
Multi-layer bottles are quite common today as they are used to ensure the freshness of goods via a barrier layer. These bottle types are produced using either of the methods above with adjustments being made via co-injection. This essentially means that different types of polymers are simultaneously injected into the make-up of the container before they are molded and blown into their final shape.
The journey of every day plastic products from warehouse to store shelves is more complex than we realize and the evolution of plastic and manufacturing has played a key role in making this material one of the largest consumed globally.
Rogers, Heather, “A Brief History of Plastic”. The Brooklyn Rail. May 1, 2005. http://www.brooklynrail.org/2005/05/express/a-brief-history-of-plastic
“Injection Blow Molding”, TricorBraunMarkting. YouTube. https://www.youtube.com/watch?v=pN-MWbcE_vM
“Jerry Can Blow Moulding Machine”, Elite Plastech. YouTube. https://www.youtube.com/watch?v=E6Fk8ZmakZk