3M has invented and discarded more forms of sticky gooey junk than you can imagine. If it's not going to be sold in 50 gallon drums or has the guaranteed demand of adhesive tape, they're not interested.
Read about the guy who invented Post-It notes in 3M and what he had to do internally to get them to actually productize it. It's far more likely that these inventors are infringing 3M's patents than that 3M would be unable to replicate it without the sample.
Could you point me in the right direction to find out more about Post-It notes? The most in-depth thing I was able to find is this article, which hints at what you are talking about but doesn't go into the full details:
So it was actually two inventors at 3M. Spencer Silver discovered the low-tack adhesive in 1968 and spent 5 years promoting it as a product within the company. He eventually hooked up with Art Fry at 3M who recognized its utility for small notes. In order to get the company to recognize it as a useful product, (as I heard the story) they had to personally make the post-it pads and distribute them to the secretaries all around the company.
Eventually some executives got hooked on the notes. The initial product launch in 1977 was deemed a failure. It wasn't until 1980 that the product was re-launched successfully.
So even after the chemistry was done, 3M's own product developers had to do 8-12 years of internal evangelism to get this new product launched to consumers.
3M has invented and discarded more forms of sticky gooey junk than you can imagine. If it's not going to be sold in 50 gallon drums or has the guaranteed demand of adhesive tape, they're not interested.
Read about the guy who invented Post-It notes in 3M and what he had to do internally to get them to actually productize it. It's far more likely that these inventors are infringing 3M's patents than that 3M would be unable to replicate it without the sample.