Polypropylene: How it’s made, Properties, Uses and The Olden Days

Updated: Mar 5


Resin Identification Code, PP, 5
PP


How is it made?

In order to Polypropylene to happen, first propylene has to be extracted from the burning of fossil fuels, afterwards is put through a polymerisation process and voilà! Polypropylene.



Properties

Abbreviated as PP, Polypropylene like the majority of plastics has good chemical resistance and has one of the highest melting point, which makes it a perfect candidate for hot food containers.


It can assume a rigid or a flexible form and it is chemically inert to acids and alkalis, which means that PP doesn’t react when in contact with those elements.



Common Uses

When it's injection-moulded is usually used in containers for yoghurt, margarine, butter and takeaway/take-out. As well as microwave and dishwasher-safe containers. Also, automobile casings and toys.


When PP is blow-moulded, its uses include bottles for ketchup, syrup and shampoo.


Besides packaging for crisps/chips, PP is also used in fibres for carpeting and bailing twine.

If it is hard to picture PP just think about those fun Tic Tac hinged cover caps/lids, and you’ll get a gist of it.


Assuming it’s recycled, it can gain a new life as automobile applications, such as signal light, battery case, battery cable, ice scrapper, oil funnel. Also, bicycle racks and shipping pallets.



The Olden Days

When it comes to the discover of polypropylene it gets, somewhat, confusing. Allegedly from 1951 to 1953, there were three patents filed. One by Robert L. Banks and J. Paul Hogan – on behalf of Phillips Petroleum Company - another by A. Zletz and the third one by Karl Ziegler - of the now called Max Planck Society.


Some outlets have Giulio Natta and German chemist Karl Rehn as the fathers of Polypropylene while others state that was Giulio Natta and his assistant Paolo Chini. Despite all of this, in 1957 the production of PP started. Ultimately, Robert L Banks and J. Paul Hogan won and were granted the patent.