I have a blender model and the mtl folder that I found before:
blender file link: https://drive.google.com/open?id=0BxFdejPeV4z3WEpMTVJGTDRsLXM
I am opening blender file and adding uv map files by selecting File-> External Data -> Find missing files and selecting "mtl_files" folder (I also added mtl file from google drive : https://drive.google.com/open?id=0BxFdejPeV4z3el80Y1djazRTX3M)
After adding mtl and uv map files it seems like this:
After that I am trying to export this file as wavefront with only this 6 options marked (File -> Export -> Wavefront):
Lastly I imported the obj file that I exported before and its uv map quality decreases a lot (if it cannot find the mtl path I am selecting the File-> External Data-> Find missing files and selecting mtl_files folder again), and it seems like that:
I have no any idea why this happens, I am doing the same process with a spider man model and it just works fine.