A solid catalyst component for the polymerization of olefins made from or containing Mg, Ti and an electron donor of formula (I)

##STR00001##

wherein R.sup.1 and R.sup.7 groups, equal to or different from each other, are selected from C.sub.1-C.sub.15 hydrocarbon groups, R.sup.2 group is selected from C.sub.1-C.sub.10 hydrocarbon groups, and R.sup.3 to R.sup.6 groups, independently, are selected from hydrogen or C.sub.1-C.sub.15 hydrocarbon groups which can be fused together to form one or more cycles.

The catalyst system based on the solid catalyst component is endowed with high activity and stereospecificity.

A solid catalyst component for the polymerization of olefins made from or containing Mg, Ti and an electron donor of formula (I)

##STR00001##

wherein R.sup.1 and R.sup.7 groups, equal to or different from each other, are selected from C.sub.1-C.sub.15 hydrocarbon groups, R.sup.2 group is selected from C.sub.1-C.sub.10 hydrocarbon groups, and R.sup.3 to R.sup.6 groups, independently, are selected from hydrogen or C.sub.1-C.sub.15 hydrocarbon groups which can be fused together to form one or more cycles.

The catalyst system based on the solid catalyst component is endowed with high activity and stereospecificity.

A polyethylene composition having the following features: 1) density from about 0.945 to about 0.951 g/cm.sup.3, determined according to ISO 1183 at 23 C.; 2) ratio MIF/MIP from about 25 to about 43; 3) MIF from about 3.5 to less than about 8.5 g/10 min.; 4) HMWcopo index from about 1 to about 40; and 5) long-chain branching index, LCBI, equal to or greater than about 0.83. The polyethylene composition can be used to produce pipes.

A polyethylene composition having the following features: 1) density from about 0.945 to about 0.951 g/cm.sup.3, determined according to ISO 1183 at 23 C.; 2) ratio MIF/MIP from about 25 to about 43; 3) MIF from about 3.5 to less than about 8.5 g/10 min.; 4) HMWcopo index from about 1 to about 40; and 5) long-chain branching index, LCBI, equal to or greater than about 0.83. The polyethylene composition can be used to produce pipes.

High flow nucleated heterophasic polyolefin compositions comprising a matrix comprising a propylene homo- and/or copolymer and an elastomeric alpha-olefin copolymer phase dispersed in the matrix, which have rather high melt flow rate, improved impact strength but also an excellent impact/stiffness balance and a process for the preparation of such a heterophasic polyolefin composition, articles made therefrom and uses of the heterophasic polyolefin composition.

High flow nucleated heterophasic polyolefin compositions comprising a matrix comprising a propylene homo- and/or copolymer and an elastomeric alpha-olefin copolymer phase dispersed in the matrix, which have rather high melt flow rate, improved impact strength but also an excellent impact/stiffness balance and a process for the preparation of such a heterophasic polyolefin composition, articles made therefrom and uses of the heterophasic polyolefin composition.

The invention is related to a new soft heterophasic random propylene copolymer with improved optical properties, as well as the process by which the heterophasic random propylene copolymer is produced.

The invention is related to a new soft heterophasic random propylene copolymer with improved optical properties, as well as the process by which the heterophasic random propylene copolymer is produced.

Solid adducts comprising MgCl.sub.2 and an alcohol ROH in which R is a C1-C20 hydrocarbon group, in which the amount of alcohol ranges from higher than 42% to 60% by weight and the porosity determined with Hg method due to pores up to 1 ?m and expressed in cm.sup.3/g, is such that the value of its ratio with the amount of alcohol in percentage falls above the straight line defined by the equation y=?0.0158x+1.03 in which y is the porosity of the adduct and x is the alcohol percentage by weight.

Solid adducts comprising MgCl.sub.2 and an alcohol ROH in which R is a C1-C20 hydrocarbon group, in which the amount of alcohol ranges from higher than 42% to 60% by weight and the porosity determined with Hg method due to pores up to 1 ?m and expressed in cm.sup.3/g, is such that the value of its ratio with the amount of alcohol in percentage falls above the straight line defined by the equation y=?0.0158x+1.03 in which y is the porosity of the adduct and x is the alcohol percentage by weight.