Silly String is a children's toy

Toy

A toy is any object that can be used for play. Toys are associated commonly with children and pets. Playing with toys is often thought to be an enjoyable means of training the young for life in human society. Different materials are used to make toys enjoyable and cuddly to both young and old...

 of flexible, sometimes brightly-coloured, plastic

Plastic

A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

 string

String

Generally, string is a flexible piece of rope or twine which is used to tie, bind, or hang other objects.Examples of string use include:* For flying kites* string figures, designs formed by weaving string around one's fingers...

 propelled as a stream of liquid

Liquid

Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...

 from an aerosol can. The solvent

Solvent

A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...

 in the string quickly evaporates in mid-air, creating a continuous strand. Silly String is often used during wedding

Wedding

A wedding is the ceremony in which two people are united in marriage or a similar institution. Wedding traditions and customs vary greatly between cultures, ethnic groups, religions, countries, and social classes...

s, birthday parties, carnival

Carnival

Carnaval is a festive season which occurs immediately before Lent; the main events are usually during February. Carnaval typically involves a public celebration or parade combining some elements of a circus, mask and public street party...

s and other festive occasions. Silly String is often sold at dollar store

Dollar store

A variety store or price-point retailer is a retail store that sells inexpensive items, often with a single price for all items in the store...

s or party stores.

Composition

The material is a polymer-based resin

Resin

Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives, and food glazing agents; as an important source of raw materials...

 which was originally formulated using the chlorofluorocarbon

Chlorofluorocarbon

A chlorofluorocarbon is an organic compound that contains carbon, chlorine, and fluorine, produced as a volatile derivative of methane and ethane. A common subclass are the hydrochlorofluorocarbons , which contain hydrogen, as well. They are also commonly known by the DuPont trade name Freon...

 propellant Freon 12

Dichlorodifluoromethane

Dichlorodifluoromethane , is a colorless gas, and usually sold under the brand name Freon-12, is a chlorofluorocarbon halomethane , used as a refrigerant and aerosol spray propellant. Complying with the Montreal Protocol, its manufacture was banned in the United States along with many other...

, one of a group of compounds believed to damage the ozone layer

Ozone layer

The ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone . This layer absorbs 97–99% of the Sun's high frequency ultraviolet light, which is potentially damaging to the life forms on Earth...

. Within a year of Silly String's introduction the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 banned Freon 11 and 12. The manufacturers then changed the formulation to use permitted propellant

Propellant

A propellant is a material that produces pressurized gas that:* can be directed through a nozzle, thereby producing thrust ;...

s.

History

Silly String was patented by Leonard A. Fish and Robert P. Cox. A United States Patent was issued to them in 1972 as a "foamable resinous composition". Cox died in February, 2008.They invented Silly String, which they originally named "Squibbly," while developing an aerosol spray cast for limbs. This information was supplied by Leonard Fish, co-inventor. Silly String and its imitators are reputed to be the largest selling novelty toy in the world because people buy multiple cans and use the Silly String quickly. It is polymer-based, likely 11-16% polyisobutyl-methacrylate

Methacrylate

Methacrylates are the salts or esters of methacrylic acid.Methacrylates contain methyl-vinyl groups, that is, two carbon atoms double bonded to each other, directly attached to the carbonyl carbon, and wherein the vinyl group is substituted with a non-terminal methyl group.Methacrylates are common...

 and 0.5 to 4% sorbitan

Sorbitan

Sorbitan is a mixture of chemical compounds derived from the dehydration of sorbitol. The mixture can vary, but usually consists of 1,4-anhydrosorbitol, 1,5-anhydrosorbitol and 1,4,3,6-dianhydrosorbitol...

 trioleate dissolved in a solvent that evaporates in the air and acts as a foaming agent

Foaming agent

A foaming agent is a surfactant, which when present in small amounts, facilitates the formation of a foam, or enhances its colloidal stability by inhibiting the coalescence of bubbles....

. The pressure in the can propels the mixture a distance of up to 20 feet (6.1 m). Other alleged ingredients are a small amount of isopropyl alcohol

Isopropyl alcohol

Isopropyl alcohol is a common name for a chemical compound with the molecular formula C3H8O. It is a colorless, flammable chemical compound with a strong odor...

 and plasticizer

Plasticizer

Plasticizers or dispersants are additives that increase the plasticity or fluidity of the material to which they are added; these include plastics, cement, concrete, wallboard, and clay. Although the same compounds are often used for both plastics and concretes the desired effects and results are...

s like dibutyl phthalate

Dibutyl phthalate

Dibutyl phthalate is a commonly used plasticizer. It is also used as an additive to adhesives or printing inks. It is soluble in various organic solvents, e.g. in alcohol, ether and benzene...

.

Silly String was licensed to and produced by Wham-O

Wham-O

Wham-O Inc. is a toy company currently located in California, USA. They are known for marketing many popular toys in the past 50 years, including the Hula Hoop, the Frisbee, Slip 'N Slide, Super Ball, Trac-Ball, Silly String, Hacky Sack and the Boogie board....

, in a range of colours including blue, red, and green, until the rights were sold to the Car-Freshner Corporation, the maker of Little Trees

Little Trees

Little Trees are disposable air fresheners in the shape of a stylized evergreen tree, marketed for use in cars. They are made of a material very similar to beer coasters and are produced in a variety of colours and scents...

, in 1997. The U.S. Patent #3705669

United States Patent and Trademark Office

The United States Patent and Trademark Office is an agency in the United States Department of Commerce that issues patents to inventors and businesses for their inventions, and trademark registration for product and intellectual property identification.The USPTO is based in Alexandria, Virginia,...

 includes a clear description of preferred implementations. Similar toys are Goofy String, Streamer String, Wacky String and Nickelodeon Smatter.

The can is advertised as containing "over 400 feet (121.9 m) of string." One measurement has shown over 1600 feet (487.7 m).

Safety

The composition of Silly String is fairly safe, but the evaporating fluorocarbon

Fluorocarbon

Fluorocarbons, sometimes referred to as perfluorocarbons or PFCs, are organofluorine compounds that contain only carbon and fluorine bonded together in strong carbon–fluorine bonds. Fluoroalkanes that contain only single bonds are more chemically and thermally stable than alkanes...

 solvent can be quite cold, theoretically capable of causing frostbite

Frostbite

Frostbite is the medical condition where localized damage is caused to skin and other tissues due to extreme cold. Frostbite is most likely to happen in body parts farthest from the heart and those with large exposed areas...

. The mixture is a very weak skin irritant. The solvent is somewhat flammable, although the polymerized string is said to be flame-resistant. The manufacturer does not recommend use near an open flame or even a warm light bulb. The flammability of Silly String as it comes out of the can has been highlighted in several home videos of Silly String sprayed near birthday cakes with lit candles, causing small but frightening fires.

In December 2006, Tween Brands Inc., a retailer of girls' clothing and accessories in the United States, was fined $109,800 by the United States Environmental Protection Agency

United States Environmental Protection Agency

The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...

 for "allegedly distributing canned confetti string damaging to the ozone

Ozone

Ozone , or trioxygen, is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope...

." EPA said the product marketed under various names by the retailer damages the stratospheric

Stratosphere

The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. It is stratified in temperature, with warmer layers higher up and cooler layers farther down. This is in contrast to the troposphere near the Earth's surface, which is cooler...

 ozone layer

Ozone layer

The ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone . This layer absorbs 97–99% of the Sun's high frequency ultraviolet light, which is potentially damaging to the life forms on Earth...

. The production and use of chemicals harmful to that layer is controlled by U.S. federal law.

Silly String may on rare occasions damage the vinyl surfaces of inflatable structures, upholstery, vinyl wallpaper

Wallpaper

Wallpaper is a kind of material used to cover and decorate the interior walls of homes, offices, and other buildings; it is one aspect of interior decoration. It is usually sold in rolls and is put onto a wall using wallpaper paste...

, and automobile vinyl tops.

Military use

Silly String and similar products have been used by American and British military forces to detect tripwire

Tripwire

A tripwire is a passive triggering mechanism. Typically, a wire or cord is attached to some device for detecting or reacting to physical movement...

s for explosive booby trap

Booby trap

A booby trap is a device designed to harm or surprise a person, unknowingly triggered by the presence or actions of the victim. As the word trap implies, they often have some form of bait designed to lure the victim towards it. However, in other cases the device is placed on busy roads or is...

s. The string is sprayed over the suspected area, and if the string falls to the ground, no tripwires are present since the string would catch on the tripwires (but is not heavy enough to activate the explosive).

it is being used by U.S. troops in Iraq for this purpose. However, because the material is an aerosol, it cannot be shipped privately to Iraq and it is not provided by official channels. Thus, 80,000 cans were unintentionally stockpiled in New Jersey

New Jersey

New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...

. In October 2007, a shipping company with the required credentials was finally found.

Bans

The use of Silly String has been banned in several places for various reasons.

It has been banned in the city of Ridgewood, New Jersey

Ridgewood, New Jersey

Ridgewood is a village in Bergen County, New Jersey, United States. As of the 2010 United States Census, the village population was 24,958. Ridgewood is an affluent suburban bedroom community of New York City, located approximately northwest of Midtown Manhattan.The Village of Ridgewood was...

 and a number of other places, and also at some public gatherings and events. The town board of Huntington in Long Island

Long Island

Long Island is an island located in the southeast part of the U.S. state of New York, just east of Manhattan. Stretching northeast into the Atlantic Ocean, Long Island contains four counties, two of which are boroughs of New York City , and two of which are mainly suburban...

 banned the sale of Silly String within 1500 feet (457.2 m) of the route of a parade.

In 2004, Los Angeles

Los Ángeles

Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...

 Mayor James Hahn

James Hahn

James Kenneth "Jim" Hahn is an American politician. Hahn was elected the 40th Mayor of Los Angeles in 2001. He served until 2005, at which time he was defeated in his bid for re-election...

 signed a council-backed ordinance (LAMC Section 56.02) to ban Silly String in Hollywood on Halloween

Halloween

Hallowe'en , also known as Halloween or All Hallows' Eve, is a yearly holiday observed around the world on October 31, the night before All Saints' Day...

night. The ordinance calls for a maximum $1000 fine and/or six months in jail for use, possession, sale or distribution of Silly String in Hollywood from 12:00 am on October 31 to 12:00 pm on November 1, a 36 hour time period.