History

• In the early 1980s, adding scents to everyday objects became one of the hottest trends. Scents were added to just about everything from pencils to stationery. During this time, sticker collecting was also extremely popular; so in order to corner a growing market, scratch and sniff stickers were invented.
  
  

Origins

• The technology utilized in scratch and sniff stickers had actually been invented 20 years earlier by scientists working for 3M. In the 1960s, 3M scientists were hard at work researching an alternative to carbon copy paper and subsequently invented a technique known as micro-encapsulation. The process of micro-encapsulation allowed researchers to make ink copies without carbon copy. 3M wanted to get more bang for their buck so they put researchers back to work trying to find alternative uses for their new micro-encapsulation technology. Eventually scientists began using this process for perfume testing strips in 1981.
  
  

Micro-encapsulation

• Micro-encapsulation works by sealing tiny scented particles within sheets of plastic, gelatin or even glass. Using a specialized printing process, thousands of microscopic bubbles are attached to the the surface of the scratch and sniff sticker. These bubbles are then sealed with a thin sheet of plastic, gelatin or glass. While these bubbles are too small to be seen with the naked eye, their scent can be extremely potent. The scent locked within the bubbles is only released when exposed to friction. When you scratch the surface of your stickers, the seal is broken and the scent contained within is released.
  
  

Applications

• Since the invention of micro-encapsulation, the scratch and sniff technology has been used in a wide variety of ways. One of the original uses for micro-encapsulation was perfume and cologne strips. These strips can now be seen in magazines and countless other advertisements. Shortly after its invention, micro-encapsulation began being used in fabrics, books and even flash cards for blind individuals as a teaching aid.
  
  

Future Uses

• The micro-encapsulation technology is now being expanded upon. In the 1990s scratch and sniff perfume strips began to include tiny bubbles of perfumed powder. Rather than simply smelling the perfume, people could now rub the scented strip directly on their skin, bursting the seal on the powder and transferring it to their skin.