In the business of invention, there are two ways to popular fortune.

One is to imagine and present a whole new realm of human activity-in short, the story of the Web browser. The other is to improve significantly on what everyone already does-the proverbial better mousetrap-and this is the story of shrink- and stretch-wrap.

Global business in books and CDs, beer cans and plasma televisions, cartons and pallet loads all rely on some form of plastic film for packaging, preservation, and protection. But how did the most ethereal of inventions come to literally cover world trade?

Europeans were the first to discover that natural latex, if stretched over goods, immediately “shrank back” to bundle them. By 1946, multiple American chemical companies had developed elastic plastic films to repeat the feat, so-called stretch-wrapping, on a factory line.

Shrink-wrap, based on the principle of ‘plastic memory,’ was even more ingenious. “If you take a rubber band and put it around a popsicle stick so it’s stretched and then you stick it in the freezer and freeze it, it will stay in that form,” explains Kenneth S. Marsh, co-editor of the Wiley Encyclopedia of Packaging Technology. “As soon as the rubber band unfreezes, however, it will return to its original form. Essentially, that’s exactly what shrink-wrap is. You stretch it and then freeze it in that stretched form, which happens to be at room temperature.”

In the war, such plastic films had seen work as a moisture seal for important military weapons and equipment. Now, though, they met the ultimate test: the automated American supermarket. The first consumer product to receive ‘wrap’ treatment was frozen poultry in 1948.

“A film bag was slipped over the bird, a light vacuum was drawn and the mouth of the bag sealed, usually with a wire tie,” recalls John Briston, author of Plastic Film. “The bag and contents were then immersed in a hot water bath when the bag shrunk tightly on to the contents.”    This tidy, impermeable, near-invisible packaging not only eliminated freezer burn, it let customers inspect their food purchases without butchers having to unwrap them.

From the supermarket to the factory, distribution center, and store shelf, applications soon abounded. By the early 1960s, in the United States alone, two dozen commercial films competed for nearly 23,000 tons in annual manufacturing contracts-this for an almost-weightless material. “Awkward shapes make little or no difference to the feasibility of shrink-wrapping,” read one early notice. What’s more, as they do today, film wraps could provide decorations or protect against pilfering.

Most important, however, plastic films could bundle. “Anything that had to be unitized tightly would be shrink-wrapped,” says Mary Ann Falkman, editor-in-chief of Packaging Digest. “That could be two bottles of shampoo and conditioner or a tray that had a twenty-four pack of beer cans-anything that you wanted to hold together.”

Aaron L. Brody, another co-editor of the Wiley Encyclopedia of Packaging Technology, agrees. “Without unitization, we couldn’t move product in this country. It’s the only way we can put products together for use on pallets in trucks to stores.”

By the 1970s, shrink- and stretch-wrap had displaced corrugated fiberboard as the central packaging material in many manufacturing situations.

Today the trend continues. “Flexible plastic materials are still growing much faster than other materials used in packaging,” says Falkman. “People are still finding new uses for film.”

Ubiquitous, inexpensive, lightweight, and invisible, shrink- and stretch-wrap may be the closest thing world trade has to a perfect product-but what are their future on a globe now choked with plastic?

“Environmentalists are attacking all plastic films,” says Aaron Brody. “They’re going to compostable polylactic acid, which some claim will compost in landfills.”

Still, he insists, this is one invention so much more efficient than the alternatives that it will be a long time before it is replaced.

“It’s a methodology for facilitating the transportation of anything and everything you use, reducing the cost, reducing the amount of material that is required, reducing the weight that is required to hold all the stuff together, thereby reducing the cost of everything. It’s that simple. It works in a very elegant way.” wt