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Plastic Plastic Everywhere

10 Jul

So, here we are on a warm summer night sitting by the campfire when the kid starts after me about my plastic identification skills… first, I have to reassert the fact that I don’t sell plastic bottles… or plastic bags… I have to constantly remind her that her lifestyle is paid for by plastic SHEET, ROD, & TUBE! And, no, Virginia, all plastics are not created equal.

(some common plastic recyling symbols)

Plastics are chosen based on which of their mechanical properties best solves the current design challenge – temperature, aesthetics, contact with chemicals, legislation (FDA, EPA), external and internal pressures, exposure to the elements, light transmission, skill sets and/or tooling available.

How many plastics do you recognize above? The wieners and buns are shrouded in polyethylene (PE) film – inexpensive, see-through printable, FDA approved. The mustard bottle is a cousin of the PE film, a type #2 recyclable known as high density polyethylene (HDPE). The mustard itself has a bit of acidity to it and can stain so you want a container that won’t absorb the colour or react to the chemical composition of its contents. Plus, what do you do with a squeeze bottle? SQUEEZE! So it has to be durable. The bottle will probably go from 3 degrees F in the fridge to 90 degrees in the summer sun so it has to be reasonable stable and shouldn’t stress out through rapid temperature changes.

The upturned ketchup bottle is recycling type #1, polyethylene terephthalate (PETE), a member of the polyester family. It’s the same material that your plastic water bottles and pop bottles are usually made of. It can be made with varying densities so you can have a very rigid bottle (sporting applications) or a semi-rigid bottle (drink, crumple, & toss).

I missed identifying the larger ketchup bottle – I figured either a polypropylene (PP) or a high density polyethylene but it turned out to be a type #7, or OTHER. This probably means that it’s a composite of recycled materials. Based on the mechanical requirements to produce a condiment bottle I was probably right with the PP or HDPE.

Just as an aside, we picked up a really neat device at Europebound on Front Street in downtown Toronto. It’s a hotdog cooker but works incredibly well for marshmallows and anything else you can skew.

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Posted by on July 10, 2007 in General Knowledge, Recylcing

 

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