Mad Monk, could you go a little into the differences between gutta percha and rubberized cloth. I've always heard that GP was closer to an early plastic while gum, or rubber was more utilized for cloth. A friend of mine collects old gutta percha items. I have a few old buttons as well.
Never got too deep into Guta-percha. It is described as the latex from a particular type of tree. Most came out of India according to the one tech book at work. From what I could gather it is a natural rubber that pre-dates tire rubber, etc. I could never learn if it was treated as natural rubber is after being collected from the trees.
When you get into early plastic, etc. there are some basics. The chemistry behind linseed oil, rubbers and modern polymers such as PVC are similar. For instance. Goodyear is credited with discovering, by accident, how to "vulcanize" natural rubber with sulfur in order to produce tire rubber. But for a long period of time prior to Goodyear, man was sort of vulcanizing linseed oil. Adding sulfur to linseed oil and heating it produces a semi-rubbery product that was used to coat leather. Then called patent leather.
I was working in a tire plant at the time and had access to the big tech library. While there was all sorts of information on the natural rubber plantations in Africa there was almost nothing to be found on the Guta-percha "latex" out of India. As far as I could learn. If you treat Guta-percha as you would plantation trees raw rubber latex you get something very similar. When you are looking at some products out of India they were very cautious not to let the basic process out of that country. Finished goods yes. Basic technology behind it? No.
Mad Monk