I am quite new to blender. I have retopologized a high poly model with texture and then bake the texture (all in cycles) to the new model in blender. When I export the obj file the mtl file comes without the map_kd texture reference. I exported with the following settings: Selection only, appply modifiers, Include edges, Write normals, Include UVs, Write materials and Objects as OBJ Objects (aso tried with "Material groups").
The texture is applyed with the following nodes: Image Texture - Diffusse BSDF - Material Output.
Any tip about what am I doing wrong?