AMORPHOUS SILICA FILLER

PURPOSE:To provide an amorphous silica filler, especially an antiblocking agent excellent in handleability, process-ability, dispersibility and abrasion resistance and, when used in a resin, excellent in mar resistance between films. CONSTITUTION:An amorphous silica having a substantially spherical apperance and a mean primary particle size of 100-270nm when determined with a scanning electron microscope, an apparent specific gravity of 0.24-0.55g/cm , a BET specific surface area of 200-500m /g, an oil absorption of 50-120ml/g and a degree of agglomeration (DA) defined as a radio of a mean primary particle diameter (D1) to a coarse particle diameter (D0) of 10-50 is used as a filler. This filler comprises substantially spherical particles which are dense and have a low oil absorption though they have a large specific surface area and therefore it excels in handleability, processability, transparency and antiblocking properties and can give a film excellent in mar resistance when used in a resin.