Scratch and Sniff Stickers
How do Scratch-N-Sniff stickers work? The basic process is called Micro-Fragrance Coating, and was originally invented by the 3M Company. This microencapsulation technology takes essential oils or an aroma-generating chemical (which might smell like bananas, pizza, or root beer), mixes it with liquified plastic or gelatin, and whips it at high speeds to produce a froth of tiny bubbles.
How tiny? These bubbles are only microns in diameter - there could be 50,000 to a square inch. This slurry is then spread on stickers, labels, or magazine inserts, and is allowed to dry. When the stickers are scratched, some of the bubbles are ruptured and the scent is released.
This is what scratch and sniff paper looks like at the microscopic level - these are the bubbles:
Scratch and sniff technology is not just limited to stickers - it can be found in children’s books, in magazine inserts such as perfume ads, greeting cards, and even on specialized business cards.It’s also been used as a safety feature in informational pamphlets for natural gas, to help teach people the smell of danger.