Particle sizes

Generally   for   high   quality   applications   with   also   higher   filler loadings   (>>   10   %)   particle   sizes   should   not   succeed   10   µm, means    medium    diameters    at    max.    2    µm.    In    that    way    any abrasive   properties   can   be   expected   to   be   minimal   and   even thinnest applications can be realized easily (i.e. 20 µm - films). This    is    valid    preferrably    for    isotropic    additives.    With    platy shaped    additives    (like    talc,    clay,    ...)    a    top    cut    of    20    µm    is recommended ...

Surface treatment

They   are   available   for   compatibilisation   of   mostly   hydrophilic minerals   (exceptions:   i.e.   talc,   graphite,   ...)   with   again   mostly hydrophobic     polymers     (i.e.     polyolefines),     additionally     to minimize shear forces (-> compounding).