A terpolymer compositions made from or containing: A) From 80 wt % to 97 wt %; of a first propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %; ii) the content of 1-butene derived units ranging from 7.2 wt % to 14.8 wt %; and B) From 20 wt % to 3 wt %; of a second propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %; ii) the content of 1-butene derived units ranging from 14.4 wt % to 26.5 wt %; and the terpolymer composition having the melt flow rate, MFR, measured according to ISO 1133 at 230° C. with a load of 2.16 kg, ranging from 3.0 g/10 min to 20.0 g/10 min; the sum of the amounts of A) and B) being 100 wt %.

A terpolymer compositions made from or containing: A) From 80 wt % to 97 wt %; of a first propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %; ii) the content of 1-butene derived units ranging from 7.2 wt % to 14.8 wt %; and B) From 20 wt % to 3 wt %; of a second propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %; ii) the content of 1-butene derived units ranging from 14.4 wt % to 26.5 wt %; and the terpolymer composition having the melt flow rate, MFR, measured according to ISO 1133 at 230° C. with a load of 2.16 kg, ranging from 3.0 g/10 min to 20.0 g/10 min; the sum of the amounts of A) and B) being 100 wt %.

A solid catalyst component for the polymerization of olefins CH.sub.2═CHR, wherein R is hydrogen or a hydrocarbon radical with 1-12 carbon atoms, made from or containing Mg, Ti, Bi, a halogen and an electron donor.

A solid catalyst component for the polymerization of olefins CH.sub.2═CHR, wherein R is hydrogen or a hydrocarbon radical with 1-12 carbon atoms, made from or containing Mg, Ti, Bi, a halogen and an electron donor.

A process for preparing fibers made from or containing propylene homopolymer having: a melting point ranging from 150° C. to 164° C.; a fraction soluble in xylene at 25° C. between 6.0 wt % and 2.0 wt %; a fraction soluble in acetone 25° C. between 0.5 wt % and 2.0 wt %; a ratio fraction soluble in xylene at 25° C./fraction soluble in acetone 25° C. between 0.30 and 0.60; a polydispersity index ranging from 2.8 to 4.5; and a melt flow rate (ISO 1133, 230° C./2.16 kg) between 2 to 40 g/10 min.

A process for preparing fibers made from or containing propylene homopolymer having: a melting point ranging from 150° C. to 164° C.; a fraction soluble in xylene at 25° C. between 6.0 wt % and 2.0 wt %; a fraction soluble in acetone 25° C. between 0.5 wt % and 2.0 wt %; a ratio fraction soluble in xylene at 25° C./fraction soluble in acetone 25° C. between 0.30 and 0.60; a polydispersity index ranging from 2.8 to 4.5; and a melt flow rate (ISO 1133, 230° C./2.16 kg) between 2 to 40 g/10 min.

A terpolymer compositions made from or containing: A) From 80 wt % to 97 wt %; of a first propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %; ii) the content of 1-butene derived units ranging from 7.2 wt % to 14.8 wt %; and B) From 20 wt % to 3 wt %; of a second propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %; ii) the content of 1-butene derived units ranging from 14.4 wt % to 26.5 wt %; and
the terpolymer composition having the melt flow rate, MFR, measured according to ISO 1133 at 230° C. with a load of 2.16 kg, ranging from 3.0 g/10 min to 20.0 g/10 min; the sum of the amounts of A) and B) being 100 wt %.

A terpolymer compositions made from or containing: A) From 80 wt % to 97 wt %; of a first propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %; ii) the content of 1-butene derived units ranging from 7.2 wt % to 14.8 wt %; and B) From 20 wt % to 3 wt %; of a second propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %; ii) the content of 1-butene derived units ranging from 14.4 wt % to 26.5 wt %; and
the terpolymer composition having the melt flow rate, MFR, measured according to ISO 1133 at 230° C. with a load of 2.16 kg, ranging from 3.0 g/10 min to 20.0 g/10 min; the sum of the amounts of A) and B) being 100 wt %.

What is disclosed is a method for preparing a catalyst system and a catalyst system for polymerizing or copolymerizing an α-olefin. Catalyst component (A) is obtained by a process of reacting a magnesium complex (A-1) containing acid salts of group IB-VIIIB elements formed by contacting a magnesium halide with an acid salt solution of group IB-VIIIB metals or spherical particles adducts, an internal electron donor (A-2) of diester or diether or composite compounds, and a titanium compound (A-3). The catalyst compound (A) is contacted with a silicon compound (B) and an organoaluminium compound (C) to complete the catalyst system providing a good balance of catalyst performance in terms of activity and stereo-specificity.

What is disclosed is a method for preparing a catalyst system and a catalyst system for polymerizing or copolymerizing an α-olefin. Catalyst component (A) is obtained by a process of reacting a magnesium complex (A-1) containing acid salts of group IB-VIIIB elements formed by contacting a magnesium halide with an acid salt solution of group IB-VIIIB metals or spherical particles adducts, an internal electron donor (A-2) of diester or diether or composite compounds, and a titanium compound (A-3). The catalyst compound (A) is contacted with a silicon compound (B) and an organoaluminium compound (C) to complete the catalyst system providing a good balance of catalyst performance in terms of activity and stereo-specificity.