Solvent free polyester (polystyrene compatible)

I don't think this is something new.

About 10years ago I saw polystyrene compatible polyester for the first time on a french site. My local polymer shop told me this is not possible and that it probably was some other type of resin.

Now my local shop released a new solvent free polyester resin themselves.

translated page: https://translate.google.com/translate?hl=nl&sl=nl&tl=en&u=https%3A%2F%2Fwww.vosschemie-benelux.com%2Fnl%2Fproduct%2Fpolyester-hars-viscovoss-hars-v-sure-eco-hars-1-kg-mekp

original page: https://www.vosschemie-benelux.com/nl/product/polyester-hars-viscovoss-hars-v-sure-eco-hars-1-kg-mekp

Does anyone here have experience with or more info about solvent free polyester resins?