The present invention relates to a polymer composition comprising at least one polymeric resin and from 0.1 to 95 wt.-% of at least one surface reactive white mineral material, a process for preparing a surface reactive white mineral material, a surface reactive white mineral material obtainable by the process, a fiber and/or filament and/or film and/or thread and/or breathable film comprising the polymer composition and/or the surface reactive white mineral material, an article comprising the polymer composition and/or the surface reactive white mineral material and/or the fiber and/or filament and/or film and/or thread and/or breathable film as well as the use of a phosphoric acid ester blend for decreasing the hydrophilicity and/or moisture pick up susceptibility of the surface reactive white mineral material-containing particle surface.