Does Self Stick Gum Deteriorate With Time?

Morning all,

Back in the day when the new self stick gum stamps first came out there was concern that the gum would deterioriate over time discoloring the stamp. Has any of these early fears caome true? Any other issues with saving these stamps?

In 1993 the British Post Office issued booklets containing 20 self-adhesive first-class stamps (SG #1789). They were orange Machins with a horizontal design. I kept a complete booklet for many years but decided to use it for postage last year when the Post Office announced that they were invalidating non-barcoded Machin stamps. When I came to use the stamps, the self-stick gum had lost all its stickiness and the stamps were just falling out of the booklet, so I had to use glue to affix them to the envelopes!

Early 'pressure-sensitive' gums can affect the stamps and discolour them. It, a;lso, can 'migrate' which may cause deterioration of the gum itself.

It is known that the gum of the first Dutch self-adhesives issued some 25 years ago caused stamps to turn yellowish. This gum was produced in Germany. More modern gums appear to be of better quality.

You are problaby thining of this self-adhesive stamp:

Which indeed deteriorated over time. The background was white when it was printed but the gum mitigated through the stamp with ugly results.

I have a large collection of US self-adhesive panes ("convertible booklets") and so far, none show any signs of falling to pieces or signs of color changelings. Firngers crossed that this will stay the same.

The self adhesive on many stamps of 1996 (like 32c Flag Over Porch) has deteriorated. There are reports of the stickiness greatly reduced, stamps popping off liners and so on.

I've been using 32c Flag Over Porch and Yellow Rose stamps on my outgoing mail for some time. They're not falling off the liner and adhere to the envelopes fine. Perhaps those that are losing their stickiness have not been stored in ideal conditions.

The self adhesive on many stamps of 1996 (like 32c Flag Over Porch) has deteriorated. There are reports of the stickiness greatly reduced, stamps popping off liners and so on.

I have hundreds of those early sa panes and booklets, including over 200 Flag Over Porch items. None show any signs of deterioration.

And I have run across a number of older Crystal Mounts pages where the stamps were in perfect condition.

Point being, when it comes to conservation issues and the critical role that environmental conditions play, we should be very careful to not draw conclusions from anecdotal observations. I think this is a consideration in philately because we do not always know the provenance of the older material we currently own.
Don

Heat and humidity are the enemies of common adhesives and paper.