Dennison Hinges

I have always heard tales that Dennison hinges can't be reproduced because the formula was lost (in a fire?). Of course, I've also heard tales that "horse parts" were used in the process of making the glue, which can't be used these days...

Regardless, I just read today a letter to the editor in The American Philatelist by someone who worked at Dennison as a coop student in college. He mentioned that Dennison has a patent on these hinges. If that is true, the patent would have all the details involved and aren't patents part of the public record? Couldn't someone be able to just look up that patent?

Anyone have any insight into this?

You might try some of these previous discussions:

https://goscf.com/t/14756&SearchTerms=dennison

A man named Benjamin A. Studley received a patent for a peelable stamp hinge in 1990. This patent info can be found here:

https://www.google.com/patents/US49...BBUeCh0CVQg3

Of course, this patent termed long ago. Mr. Studley referenced a Dennison Manufacturing Company patent from 1964, so it's possible that 1964 was the last time Dennison had any new IP for a peelable stamp hinge. Of course, this patent also termed long ago:

https://www.google.com/patents/US31...SKMeCh1R5QRK

Yesterday I got a "bag of stamp stuff" for free from someone in the my neighborhood. Mostly common stamps torn off envelopes, but the bag had two unopened old packs of Dennison hinges and a nice pair of tongs. Nice find