The main ingredient used to make bulk bags all over the world is polypropylene. The global market for polypropylene was over $80 billion USD in 2014, with a projected growth rate of almost 7% YoY moving forward.
Why such a huge number?
Well, if you consider how many everyday items are made from that cute little chain of carbon and hydrogen, you will understand why so much of it is produced. Today I want to take a closer look at one of the most versatile building materials on the planet.
Science: It gets better when you mess things up on purpose
The first polymerization of polypropylene happened in 1951. Working for Phillips Petroleum Company, Robert L. Banks and J. Paul Hogan made an interesting discovery while trying to find practical uses for the gaseous by-products of gasoline refining. Their company was looking for new product lines to sell to the general public.
The previously huge and lucrative demand for oil dropped sharply with the ending of WWII. Polypropylene and ethylene were being produced constantly by their refinery, and there was no real good way to utilize these gases for general public use.
That is until they decided to add a small amount of chromium oxide to their regular mix of nickel oxide catalyst. I know, crazy, right?!?
Long story short, the nickel oxide produced the expected liquids, but the chromium oxide had produced a solid, white material. The birth of a new polymer had occurred: polymerized polypropylene!
The scientific community was very excited about this new discovery. So were the patent lawyers, but that is another story. Before long, new and improved polymers were being developed around the globe.
Giulio Natta of Italy and Karl Rehn of Germany are credited with taking the 1951 discovery to new levels. Their creation of a crystalline isotactic polymer known as polypropylene really launched the plastics revolution. Their improved chemical process also allowed for the large-scale commercial production of polypropylene we see today.
Applications: Heavy duty bulk bags, sturdy auto parts, solid containers, and….Diapers?
So what is it about polypropylene that makes it so versatile? For one, it is very resistant to fatigue. Pretty much any food or beverage container that has a living hinge is made from polypropylene.
A racy picture of polypropylene with nothing on
When it comes to human consumption, there is negligible chemical leeching with polypropylene so it is commonly used in many food grade containers. Like bulk bags, imagine that!
Speaking of bulk bags, what makes polypropylene the material of choice for heavy-duty bags? Polypropylene is relatively inexpensive compared to polyethylene or polyester. On top of that, it is very resistant to corrosion and has great colour fast properties.
In addition, it is resilient to physical damage, impacts, and freezing. A bulk bags natural habitat extends from the Equator to the North Pole, so they have to be built to last.
It also has a rather high melting point, about 160 degrees Celsius. That makes it ideal for use in laboratories as polypropylene will keep its cool in an autoclave. It also makes for excellent food storage containers that can be microwaved and thrown in the dishwasher as well.
An interesting fact about your favorite RubberWare or TupperMaid container is that the lid is usually made of a different, softer poly grade than the body. This is so the more flexible lid will snap onto the more rigid container.
Finally, if you’re like most people, when you think of Exxon Mobil you think of cute little babies. Polypropylene resin can be spunbond into ultra-soft fibers to make a very durable and drape-able fabric.
This is another method of manufacturing polypropylene into something completely new. Instead of being woven it is processed in such a way that a fine, uniform fabric is created. And you guessed it, this version of the Wonder-Poly can even be used to make diapers!
So what can polypropylene do for you?
It is clear that polypropylene is truly one of the most versatile building materials around. Like all plastics, it is derived from the refining of petrochemicals. In spite of all the uses for this material, in our opinion, the best polypropylene is made into bulk bags!
If you are interested in getting your hands on some woven polypropylene totes, contact us today. If you are looking for diapers… try ExxonMobil.
If you wish to read more about polypropylene, our friends at Omnexus by Special Chem have a very in-depth paper on that wonderful material!