Re: Scratch and Sniff Stickers

Morgan

I'm sorry to say that a high school chemistry lab is not equipped to make a 
Scratch-N-Sniff sticker [hereafter SNSS].

Here's why:

Thne SNSS consists of [at least] six highly specialized components; Form the 
top down, they are:

1. A microencapsulated fragrence produced by the suspension polymerization of 
the fragrence in the presence of a micelle forming monomer which is not soluble 
in the fragrence itself, yielding a one micron diameter particle with rigid 
walls that is impermeable to the fragrence.

2. A binder [glue] to stick a very thin layer of these microcapsules onto a 
sheet of paper.

3. The paper itself needs to be specially treated [sized] to prevent the 
glue/capsule mix from soaking in to the body of the paper but keeping it on the 
surface only.

4. On the back side of the paper you will need to apply a thin coating of a 
pressure sensitive adhesive. These can be water or solvent borne or applied via 
melt techniques. This layer is at least as difficult to synthesize as the 
fragrance layer.

5. The adhesive coating is then laminated to a piece of release paper [backing 
paper]. This too is a modified paper with high internal strength and  is always 
coated on one side with a catalytically cured polysiloxane, which exhibits a 
very low surface free energy to permit easy peeling of the SNSS from the backing

6. Finally, there is usually some printing/instructions on the backside of the 
backing paper which gets us into printing inks and all of that technology...


This is a very difficult project you've chosen. I don't even know where I would 
start to send you to get the materials together for such an experiment much 
less teach you all the technology needed to pull it off. 

Ken,    email me at kayjay45@home.net if you still have questions