I have a few patents and RDs on that subject. We used a copolymer with sulfur and nitrogen in it for pptn and a terpolymer for coating which had a crosslinking site. For color, we used a coupler grafted onto the terpolymer.
Unfortunately, these things are hard to get and expensive. But, I do consider this seriously. OTOH, with all of the byproducts of cattle out there, why not make sure that they are not left to go to waste, but rather are used in a good cause.
So, there is my position on this! I'll leave veggie emulsions for you!