Know Your Plastics - Polypropylene... It's a Living Hinge

A Living Hinge? No - it's not a misheard 70s anthem from the amazing Electric Light Orchestra. Living hinges are made from the same material as the two pieces they connect - usually from a single mould. Not sure? Grab a pack of Tic Tacs - that's a living hinge on top. This is one of the most common uses of Polypropylene (PP) and illustrates much about this plastic. Grabbing your refillable water bottle and heading to gym? My Camelbak drink bottle is made from PP. Look for Recycle Symbol Number 5.

ANOTHER SPECIAL PLASTIC?

Each week, we consider a different plastic and are learning they're all a bit different - sometimes a lot different. PP is a big one to chat about - it's the second most popular synthetic plastic (Polyethylene takes the crown) and you're surrounded by it. What's more, you'll need to consider it for retail applications from time to time. Let's see why!

PROPERTIES OF NUMBER 5

Here's some notable things about this common plastic and about how this could relate to display fixtures and fittings:

• Low Density but Tough - not heavy, but can handle heavy punishment - this alone may sway you to PP
• Opaque - PP can be made transparent, but its more natural state is to be opaque (think your plastic drink bottle again). This can provide an interesting display effect
• Highly Resistant to Fatigue - hence the living hinge. Bend it back and forth, it doesn't begin to break like other plastics (try bending a piece of PVC back and forth, you'll see it discolour and become brittle quite quickly)
• Colourfast - when coloured, it stays that way - but keep it inside! PP degrades with UV
• Chemically Resistant - the reason it's popular for contact with food and liquid. Not only does it not absorb water - it also resists fats. Straws, ice cream containers - more examples of PP and its safe use around foods. And if it gets a little warm, this still doesn't change, and no nasties leach out.
• It's reusable - we've all heard not to refill the bottle of water we bought at the service station, that's sat on the front car seat for a couple of days. That's PET - use it once only. PP can be used over and over, just keep it clean.
• Recycling time - once it has served its purpose, PP is easily recycled. 

SO IT'S PERFECT?

For some retail display applications, PP's properties make it a terrific choice. It's also very easy to manufacture and the raw material cost is on the lower side, so it is generally an economical selection. There's some warning signs to watch for though, so cross it off your list based on these things - 

• UV - the achilles heel of PP, UV will cause PP to degrade. Generally not suitable for use in direct sunlight
• Temperature - PP can be used in higher temperatures and is commonly used in medical applications, where containers going into autoclaves for sterilisation are made from it. However, PP expands considerably in heat, so there will be situations where it should not be used. Consider this specifically in food preparation areas.
• Colour - colour holds superbly when this plastic is manufactured. However, grab some PP and you'll feel it's slippery. This type of surface doesn't bond well with other materials. You can't paint it and you can't glue things to it. 

As an example, here's a product we make from PP. We've used this plastic for the top platform on the display wagon, for the following reasons - 

1. It's lightweight - as this is a modular product and the platform can be taken off for other applications, it needs to be easy to assemble, disassemble and carry for one person
2. It's tough - the platform will often have significant weight on it
3. Economical - a complex component can be manufactured comparatively quickly, keeping cost down
4. Moisture-resistant - many customers display fresh produce on these platforms, so we expect them to get wet and dirty. in this case - easily cleaned and no leaching of chemicals into food.

IN SUMMARY

Polypropylene has its place as a choice for retail display, suitable for indoor displays and around food. Suits large plastic components and can take some serious punishment. Avoid it if you need to paint, glue or stick to it - this is an item that arrives to you in its final form! And recycle when you've finished, it's one of the very best choices for this.

Author profile

Steve Nelson believes in incredible retail spaces that sustain communities. Steve is a Retail Display specialist, who has worked with iconic retailers across the globe. As leader of Euroswift Retail Creations in Australia, his focus is delivering solutions and techniques that help retailers develop dexterity at the shop floor, to predict the needs of their local community and react rapidly. Connect with Steve on LinkedIn