UV map quality decreases after importing wavefront object that is exported as obj before 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.
I solved my problem by enabling "normal map" from texture tab of properties. After I enabled this option, everthing seemed normal again (Properties tab-> Texture tab -> Show material textures -> select the normal -> mage sampling -> Enable Normal Map ).