Re: Without using free NaOH, how do you dissolve polyester film?

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
xpetersonx@aol.com