A Professor Plastics Feature ArticleSee Other Articles
Any idea what Izod impact is? Perhaps something to do with preppie shirts? Nah …
Actually, it’s a test – a strength test for determining how “impact resistant” something is. In other words, it determines how hard you can whack something before it shatters or breaks. (Toddlers are particularly interested in this concept…)
Based on how much impact energy a material can absorb, an Izod impact strength number is assigned: the higher the number, the tougher the material.
Why is this important? Well, think about your morning shower in the bathroom. Sometimes the shampoo bottle becomes slippery and tumbles to the shower floor. Would you like a bottle made from a material with a low Izod impact strength number – let’s say glass – or a material with a higher number? (Yes, me too.)
So when a company that makes shampoo – or sunscreen or body lotion or mouthwash – goes looking for the right bottle, tube or container to use, its packaging experts ask themselves (among many other things): where will this be used … and what happens if somebody drops it? That answer, including the Izod impact strength of the material, helps them determine the type of material to use.
Different plastics have varying Izod impact numbers. They can range from fairly low to exceptionally high. Polycarbonate, for example, which often is used to make “bullet proof glass”, has an extremely high Izod impact number.
The type of plastic used most often in the bathroom is HDPE, or high-density polyethylene, a plastic with moderate Izod impact strength – plenty to prevent a shampoo bottle from shattering – plus a whole bunch of other properties that make it suitable for the steamy, wet bathroom with unforgiving tile flooring.
One of the other things these packaging experts are asking: Is the packaging recyclable? Fortunately, today more and more communities are collecting all sorts of everyday plastics for recycling – including many of those used in personal care products.
Thus ends today’s lesson. Now go check out Bathroom to Bin… a fun, interactive way to learn a bit more about the plastics used in the bathroom – and how easy it is to recycle many of them.