Scratch and sniff technology is the application of a fragrant coating to items such as stickers or paperboard, so that when the coating is scratched it releases an odor that is normally related to the image displayed under the coating. The technology has been used on a variety of surfaces from stickers to compact discs. Gale W. Matson accidentally invented the technology while working for 3M in the 1960s. He was attempting to create a new method for making carbonless copy paper using microencapsulation.[1] The technology to infuse microcapsules and paper was submitted to the US patent office on November 18, 1969, and the patent was granted on June 23, 1970.[2] Despite the technology being invented by Matson in the 1960s and its subsequent success in the 1970s, the first patent for a translucent fragrance releasing version of microcapsules wasn't issued until January 15, 1985, to the 3M corporation.[3]
One of the earliest uses of scratch-and-sniff technology can be found in the 1971 children's book "Little Bunny Follows His Nose," which features various smellable objects such as peaches, roses, and pine needles.[4][5] Stickers and labels became popular in the late 1970s, and remained so through to the mid-1980s. In 1977, Creative Teaching Press produced some of the earliest scratch and sniff stickers, primarily marketing them to teachers as rewards for their students.[6][7]
Scratch-and-sniff stickers are occasionally used to help diagnose anosmia,[8][9] though the Alcohol Sniff Test, which uses vaporised 70% isopropyl alcohol, is far more common.[10][11] Some utility companies enclosed scratch and sniff cards in their bills to educate the public in recognizing the smell of a methane gas leak. In 1987, cards distributed by the Baltimore Gas and Electric Company led to a rash of false alarms when the scents of cards in unopened envelopes were mistaken for real gas leaks.[12]
Scratch and sniff is created through the process of micro-encapsulation. The desired smell is surrounded by micro-capsules that break easily when gently rubbed. The rub to release action breaks the micro-encapsulated bubbles and releases the aroma. Because of the micro-encapsulation, the aroma can be preserved for extremely long periods of time.
While there were hundreds of companies that put out Scratch and Sniff stickers, the most well known are the originators Creative Teaching Press (CTP) (who later renamed them Sniffy's in 1980/1981), Trend Enterprise's Stinky Stickers line (which followed directly after CTP), Hallmark, Sandylion, Spindex, Gordy, and Mello Smello.
Apart from the stickers, scratch and sniff surfaces are to be found on some objects in popular culture:
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