| abstract |
The invention provides new prepolymerized catalyst components for the (co)polymerisation of olefins CH2=CHR, wherein R is hydrogen or a C1-C12 alkyl group, characterized by comprising a solid catalyst component, comprising Ti, Mg, halogen and an electron donor compound, being capable of yielding, under standard polymerization conditions, a propylene homopolymer having an insolubility in xylene at 25 °C higher than 90 %, which is prepolymerized with ethylene to such an extent that the amount of the ethylene prepolymer is up to 100g per g of said solid catalyst component. These such catalyst components allow to obtain a high catalyst activity, a high isotactic index and are not affected by aging. |