Basell Poliolefine Italia S.r.l.

Basell Poliolefine Italia, S.p.a.

Hans-Jürgen Zimmermann

Wolfgang Bidell

Paola Massari

Guenther Schweier

Roland Hingmann

Günther Schweier

Jean News

Joachim Rösch

Joachim Roesch

Jürgen Oelze

Ulrich Dahn

Ulrich Clemens Dahn

The present invention relates to a process for preparing propylene polymer compositions in at least two-stage process wherein, in a first stage, a propylene homopolymer or a propylene copolymer comprising propylene and at least a CZ-CIO-1-alkenes other than propylene, containing at least 85% by weight of propylene, is prepared by polymerization and, in a second stage, ethylene and at least a comonomer selected from propylene and C4-C,o1alkenes are polymerized to give an ethylene polymer, comprising at least 90% by weight of ethylene, wherein the amount of the ethylene polymer in the propylene polymer composition ranges from 10 to 50% by weight and the propylene polymer composition has a melt flow rate MFR, in accordance with ISO 1133 at 230&#xb0; C. and 2.16 kg, of from 2 to 50 g/10 min.

At least two-stage process for preparing propylene polymer compositions

Olefin polymer composition comprising (by weight, unless otherwise specified): A) 60-95% of a propylene homopolymer or copoloymer having a Polydispersity Index (P.I.) value of from 4.6 to 10 and a content of isotactic pentads (mmmm), measured by 13C NMR on the fraction insoluble in xylene at 25&#xb0; C., higher than 98 molar, B) 5-40% of a copolymer of ethylene containing from 40% to 70% of propylene or C-C&#x3b1;-olefins) or of combinations thereof, and optionally minor proportions of a diene; said composition having a Temperature Rising Elution Fractionation (TREF) profile, obtained by fractionation in xylene and collection of fractions at temperatures of 40&#xb0; C., 80&#xb0; C. and 90&#xb0; C., in which the ethylene content Y of the fraction collected at 90&#xb0; C. satisfies the following relation (1): Y&#x2266;&#x2212;0.8+0.035X+0.0091Xwherein X is the ethylene content of the fraction collected at 40&#xb0; C. and both X and Y are expressed in percent by weight, and a value of intrinsic viscosity [&#x3b7;] of the fraction soluble in xylene at 25&#xb0; C. of from 1.8 to 4.2 dl/g.

Impact resistant polyolefin compositions

The invention relates to highly flowable propylene block copolymers that comprise 50 to 80 wt.-% of a propylene homopolymer and 10 to 70 wt.-% of a propylene copolymer having 5 to 50 wt.-% of a C&#x2013;Calk-1-ene polymerized into it that is different from propylene, and that are obtainable from the gaseous phase by a two-step polymerization by means of a Ziegler-Natta catalyst system. In a first polymerization step, the propylene is polymerized at a pressure of 10 to 50 bar, a temperature of 50 to 100&#xb0; C. and an average dwelling time of the reaction mixture of 0.3 to 5 hours in the presence of at least 2.0% by volume, based on the total volume, of hydrogen. The propylene homopolymer obtained in said first polymerization step is transferred together with the Ziegler-Natta catalyst system into an intermediate container, expanded for 0.01 to 5 minutes to less than 5 bar and maintained at a temperature of 10 to 80&#xb0; C. The pressure in the intermediate container is then increased by 5 to 60 bar by introducing under pressure a gaseous mixture, and the propylene homopolymer is then transferred to a second polymerization step together with the Ziegler-Natta catalyst system. In said second polymerization step, a mixture from propylene and a C&#x2013;Calk-1-ene is polymerized into the propylene homopolymer at a pressure of 10 to 50 bar, a temperature of 50 to 100&#xb0; C. and an average dwelling time of 0.5 to 5 hours. The weight ratio between the monomers reacted in the first and those reacted in the second polymerization step are adjusted to be in the range of from 4:1 to 1:1.

Highly flowable propylene block copolymers

Growing community of inventors

Bensheim, Germany

Hans-Jürgen Zimmermann