system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How scratch-n-sniff paper can hold scents for months?
gpt
I work for an ink manufacturer and we also produce these kinds of inks.
The base used for these is usually a water based lacquer, which means polymers with additives in water.
The additives are usually adjusted to make the lacquer a little softer when dried so the surface is a little more tacky.
To this base mixture we add different perfume premixes, the lacquer is then printed as the last layer on whatever design the customer requested from the printing company.

When you now rub the lacquer you partially damage the surface which will release more perfume in return, also the rubbing creates heat which again releases more perfume.

As the perfume is trapped in the lacquer which is a relatively thick layer it lasts for a very long time.

It is also possible to make textured lacquers with perfumes to create a tactile feedback on the perfumed surfaces.