Granulate of mineral filler concentrate and method of producing granulate of mineral filler concentrate

Abstract

The subject of the application is a mineral filler concentrate granulate containing 60-80% barium sulfate, 15-30% controlled-transparency polymer, 0.5-5% compatibilizer, 0.1-2% dispersant, 0.05-1% phenolic antioxidants, and up to 1% clarifiers. The granulate contains barium sulfate crushed to a fraction d50 = 0.6 micron and d98 = 1.7 micron, with the barium sulfate being surface modified. Low-density polyethylene with a melt flow index of 1-6 g / 10 min (190°C, 2.16 kg) or a polypropylene homopolymer with a melt flow index of 1-6 g / 10 min (190°C, 2.16 kg) is used as the controlled-transparency polymer.The application also covers a method for producing mineral filler concentrate granules, which consists in mixing 60-80% barium sulfate, 15-30% polymer with controlled transparency, 0.5-5% compatibilizer, 0.1-2% dispersant, 0.05-1% phenolic antioxidants, and up to 1% clarifiers in a mixer, and then subjecting it to granulation using the "cut in air" method. Barium sulfate with a d50 = 1 micron and d98 = 3 microns fraction is additionally crushed in a ball mill to a d50 = 0.6 micron and d98 = 1.7 micron fraction, and then chemically surface modified. Surface modification takes place in a 5 - 15% solution of vinyl ethoxysilane in 70 - 90% isopropanol and 5 - 15% water acidified with acetic acid to pH = 6 in a high-speed mixer at room temperature.