|MadSci Network: Chemistry|
I surmise that your solution that you use to remove the polyester is a string sodium hydroxide solution. Is that correct? The polyester is probably going through a reverse condensation, or the opposite of what it went through to be made into a polyester from a monomeric material. It is not necessarily returning to the monomeric state. The backing material can be one of many materials, but is likely an elastomer containing acid functionalities. Polyacrylic acid or polymethacrylic acid are tow possibilities. These are formed from carbene or free radical reactions so they have the acid groups hanging off the chains rather than being part of it. If the acid group is neutralized, it becomes a salt, but that is all, the carbon backbone remains intact. I know you want to use non-VOC compounds to remove the decal backing, and if you find something that works, please let me know immediately. Otherwise, if you are willing to try a VOC type material, mix 1/2 isobutanol with 1/2 xylene by weight. A distant possibility is using very hot motor oil. That is cheating somewhat, since the hot oil will not dissolve the polymer, but will melt it off. In either case, please consult an expert about safety equipment you will need. If you still have problems, let me know directly. Ed Peterson, PhD firstname.lastname@example.org
Try the links in the MadSci Library for more information on Chemistry.