At picnic time, what do we cover the potato salad with? Here’s a casserole for the in-laws; what shall we wrap it in? Stick the leftover dinner in the fridge but first cover it with… As you might suspect, the solution in all the above situations is likely to be plastic wrap. Yes, this thin, clear plastic film has become an integral part of our culinary preparations since it became publicly available in 1952. Even though there’s hardly an American who doesn’t know what it is, almost no one knows how plastic wrap is made. Read on to find out how chemical-laden crude oil becomes food-grade plastic wrap.
First, the most basic raw materials are processed to make a suitable grade of plastic. This involves a lot of heating, pressurizing, and the addition of LOTS of strong chemicals. The end result is granular plastic bits.
These plastic granules are put into a boiler that heats them melting point, which is between 200 and 400 degrees, depending on the specific type of plastic being used. The liquid plastic is then forced through a die that squeezes it out as a rope of warm, elastic plastic. As the tube is squirted out, it is carried along a path lined with air nozzles.
These air nozzles are injected into the side of the tube of plastic and blow it into huge bubbles much like we blow bubble gum. This blowing process stretches the plastic to the necessary thinness of plastic wrap. The huge bubble is then gathered up and fed between two rollers to make it into a film of plastic. The film is then wrapped around a tube to make a gigantic roll. Just one of the rolls may easily hold enough plastic wrap to stretch over several miles.
Next the mega roll is unrolled and cut to fit the standard consumer-sized cardboard tubes and boxes. This is usually a size of about 50 feet long by a foot wide. Interestingly, all this rolling, unrolling, and re-rolling builds up a bit of static electricity in the plastic. This charge is what make the clinging effect of cling wrap. Once it is re-rolled on its final cardboard tube, the plastic wrap is boxed, sealed, packed and shipped.
The plastic wrap arrives at your local store and you go in there, pick up a box, and take it home. There you have it. This same plastic wrap has come all the way from bits of melting plastic to the convenient wrap that plays such a major role in your everyday life.