Hobbies And Interests
History
Silly string was patented in 1972 by the company Wham-O after being co-invented by Robert Cox and Leonard Fish. Although Silly String was originally the only product of its type, there are now similar products marketed under different names.
Significance
Silly string has little functional significance other than creating a festive environment for parties and celebrations. In fact, the original patent states that Silly String has "substantial play and decorative utility" (see Resources below). More pragmatically, Silly String has been implemented in the Iraqi war to detect the presence of trip wires in potentially unsafe areas.
Identification
Silly string is a plastic resin that is in a liquid form within the Silly String can. The patent for Silly String gives a long list of potential polymers that can be selected to create it. Most commonly, however, it is made up of approximately 11 to 16 percent polyisobutyl-methacrylate and 0.5 to 4 percent sorbitan trioleate. These materials are contained within a solvent, which was originally a CFC-based (chlorofluorocarbon) compound. Because these compounds have been deemed unsafe for the ozone layer, similar but safer compounds have replaced the CFCs. However, there are some companies that still use CFC-based propellants, though not in the United States. Small amounts of pigments are added that do not alter the chemical structure or the intended effectiveness of the Silly String.
Effects
When sprayed from the can, the solvent quickly evaporates, leaving a solid resin. This evaporation occurs so quickly that it appears to be solid upon leaving the can. The dried resin remains tacky enough to stick to walls, windows, hair and nearly any other surface it comes into contact with.
Warning
Because coolant is shot from the can at the same time as the Silly String, it can burn (or frostbite) the skin on contact. Thus care must be taken to keep fingers away from the spout, as well as not to shoot the Silly String too closely to someone. It can also be a skin irritant to those sensitive to its ingredients. Because Silly String is essentially a plastic, it is not biodegradable and is a significant environmental pollutant that has been banned from many cities.