Resumen
[0001] A catalyst system is provided that produces polyethylene having broad molecular weight distribution. The catalyst system according to the invention comprises two active catalysts: a chromium-containing (Phillips) catalyst and a titanium-containing (Ziegler) catalyst. Both catalysts are supported on silica. The components of the catalyst system may be introduced into the olefin polymerisation reaction through individual dosing, or they may be pre-mixed for joint addition in pre-determined combinations known to favor production of particular resin formulations. Delivery of the catalytic components during reactor dosing is more accurate: kinetic reaction parameters can be stabilized, and the characteristics of the polyolefin resin product regulated more accurately.