Basf Aktiengesellschaft

Patrik Muller

Franz Langhauser

Meinolf Kersting

Jurgen Kerth

Rainer Alexander Werner

David Fischer

Gunther Schweier

Rainer Hemmerich

Erich Kolk

Stefan Seelert

Peter Kolle

Stephan Seelert

A process for preparing random propylene copolymers containing copolymerized C.sub.2 -C.sub.10 -alk-1-enes by polymerization of propylene and C.sub.2 -C.sub.10 -alk-1-enes in the presence of a Ziegler-Natta catalyst system comprising a titanium-containing solid component a) comprising a compound of magnesium, a halogen, silica gel as support and a carboxylic ester as electron donor compound, and also, as cocatalysts, an aluminum compound b) and a further electron donor compound c), where propylene and the C.sub.2 -C.sub.10 -alk-1-enes are polymerized with one another at from 50 to 100.degree. C. at pressures in the range from 15 to 40 bar and mean residence times of from 0.5 to 5 hours and the support used in the titanium-containing solid component is a silica gel which has a mean particle diameter of from 5 to 200 .mu.m, a mean particle diameter of the primary particles of from 1 to 10 .mu.m and voids or channels having a mean diameter of from 1 to 10 .mu.m, which voids or channels have a macroscopic proportion by volume based on the total particle in the range from 5 to 20%.

Process for producing improved random propylene copolymers

Propylene polymers which comprise from 25 to 97% by weight of a propylene polymer (I) containing from 0 to 15% by weight of copolymerized C.sub.2 -C.sub.10 -alk-1-enes and also comprise from 3 to 75% by weight of a further propylene polymer (II) containing from 15 to 80% by weight of copolymerized C.sub.2 -C.sub.10 -alk-1-enes, are obtainable by two-stage polymerization of propylene and C.sub.2 -C.sub.10 -alk-1-enes in the presence of a Ziegler-Natta catalyst system which comprises a titanium-containing solid component a) comprising a compound of magnesium, a halogen, silica gel as support and a carboxylic ester as electron donor compound, and also as cocatalysts an aluminum compound b) and a further electron donor compound c), where, in a first polymerization stage, propylene is polymerized in the presence or absence of further C.sub.2 -C.sub.10 -alk-1-enes at from 50.degree. to 100.degree. C., pressures in the range from 15 to 40 bar and a mean residence time of from 0.5 to 5 hours and subsequently, in a second polymerization stage, a mixture of propylene and further C.sub.2 -C.sub.10 -alk-1-enes is polymerized at from 30.degree. to 100.degree. C., pressures in the range from 15 to 40 bar and mean residence times of from 0.5 to 5 hours onto the propylene polymer obtained from the first polymerization stage, and the silica gel used as support for the titanium-containing solid component has a mean particle diameter of from 5 to 200 .mu.m, a mean particle diameter of the primary particles of from 1 to 10 .mu.m and voids or channels having a mean diameter of from 1 to 10 .mu.m, which voids or channels have a macroscopic volume as a proportion of the total particle in the range from 5 to 20%.

Propylene polymers

Random propylene copolymers containing copolymerized C.sub.2 -C.sub.10 -alk-1-enes are obtainable by polymerization of propylene and C.sub.2 -C.sub.10 -alk-1-enes in the presence of a Ziegler-Natta catalyst system comprising a titanium-containing solid component a) comprising a compound of magnesium, a halogen, silica gel as support and a carboxylic ester as electron donor compound, and also, as cocatalysts, an aluminum compound b) and a further electron donor compound c), where propylene and the C.sub.2 -C.sub.10 -alk-1-enes are polymerized with one another at from 50.degree. to 100.degree. C. at pressures in the range from 15 to 40 bar and mean residence times of from 0.5 to 5 hours and the support used in the titanium-containing solid component is a silica gel which has a mean particle diameter of from 5 to 200 .mu.m, a mean particle diameter of the primary particles of from 1 to 10 .mu.m and voids or channels having a mean diameter of from 1 to 10 .mu.m, which voids or channels have a macroscopic proportion by volume based on the total particle in the range from 5 to 20%.

Random propylene copolymers

Highly flexible propylene/ethylene copolymers having a high rubber content are obtainable by two-stage polymerization from the gas phase in an agitated fixed bed by means of a Ziegler-Natta catalyst system which, in addition to a titanium-containing solid component, also contains an aluminum compound as a cocatalyst, in a first polymerization stage, propylene being polymerized at from 15 to 40 bar and from 50.degree. to 90.degree. C. and during an average residence time of the reaction mixture of from 0.5 to 5 hours and then, in a second polymerization stage, a mixture of propylene and ethylene being polymerized with the polymer discharged from the first polymerization stage, at from 5 to 30 bar, this pressure being at least 2 bar below the pressure of the first polymerization stage, and at from 60.degree. to 100.degree. C. and during an average residence time of the reaction mixture of from 0.5 to 5 hours, the ratio of the partial pressure of propylene to that of ethylene being brought within the range from 0.5: to 5:1, the weight ratio of the monomers reacted in the first polymerization stage to those reacted in the second polymerization stage being from 0.9:1 to 0.4:1 and the polymerization in the second polymerization stage being carried out in the presence of a C.sub.1 -C.sub.8 -alkanol.

High flexible propylene/ethylene copolymers and process for preparing

A process for the preparation of Ziegler-Natta type catalyst systems, containing, as active constituents a) a titanium-containing solid component, which contains in addition to a compound of titanium at least one electron donor compound, and is present in an inert solvent in the form of a suspension, and, as co-catalyst, b) an aluminum compound and c) optionally further electron donor compounds in which, following the preparation of the titanium-containing solid component a), the inert solvent present in the suspension is removed by first filtering the suspension in a first step, and then removing further solvent from the filtered material in a second step by applying a pressure difference at temperatures of not more than 100.degree. C.

Preparation of Ziegler-Natta type catalyst systems

Propylene polymers contain A) a semicrystalline propylene homopolymer having a melting point of 125 to 165.degree. C. and a glass transition temperature which is greater than -10.degree. C. and B) a semicrystalline propylene homopolymer having a melting point below 130.degree. C. and a glass transition temperature which is less than or equal to -10.degree. C. or a non-crystallizing propylene homopolymer having a glass transition temperature which is less than or equal to -10.degree. C.

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Kaiserslautern, Germany

Patrik Muller