Hoechst Aktiengesellschaft

Clariant Corporation

Messer Griesheim Gmbh

Hostalen Polyethylen Gmbh

Clarian & Gmbh

Ludwig Bohm

Walter Spaleck

Martin Antberg

Gerd Hohner

Hans-Friedrich Herrmann

Rainer Lecht

Jurgen Rohrmann

Joachim Berthold

Hartmut Voigt

Hartmut Luker

Werner Breuers

Andreas Winter

Volker Dolle

Manfred Eschwey

Rolf Van Bonn

Ulrich Schulte

Bernd Diedrich

Reiner Hess

Manfred Fleissner

Andreas Heinrich

Eckard Raddatz

Rainer Kaps

Hans Joachim Vetter

Heiner Bromstrup

Horst Jarstrow

Johannes Friedrich Enderle

Hans-Frieder Enderle

Olaf Heine

Hans-Albrecht Scholz

A catalyst formed by the reaction of a magnesium alkoxide dispersion having a particle size of from 100 to 3000 nm with a compound of a metal selected from the group comprising titanium, zirconium, vanadium and chromium and then with a chlorine-containing organoaluminum compound possesses a very good hydrogen responsiveness and a high activity even in the presence of molecular-weight regulators such as hydrogen. The catalyst is therefore outstandingly suitable for the production of low molecular-weight polyolefins. The catalyst makes possible the production of waxes having a reduced residual ash content. The large particle diameter and the low fines content of the polymer powder produced by suspension polymerization with this catalyst enables easy removal of the suspension medium and drying. The catalyst is furthermore advantageously used in solution polymerization and, because of the large particle diameter, in gas phase polymerization for producing low molecular-weight poly-1-olefins.

Process for producing low molecular-weight poly-1-olefins

The invention relates to a high strength pipe of ethylene polymer having a bimodal molecular weight distribution. Such pipe has a stress cracking resistance of .gtoreq.1400 h, a fracture toughness of .gtoreq.7 mJ/mm.sup.2 and a modulus of creep in flexure, measured according to DIN 54852-Z4, of .gtoreq.1100 N/mm.sup.2. The pipe according to the invention is produced from an ethylene polymer in which the ratio of weight of the low molecular weight fraction to the weight of the higher molecular weight fraction is in the range from 0.5 to 2.0 and which has a melt flow index MFI.sub.5/190.degree. C. of .ltoreq.0.35 g/10 min. It is particularly suitable for the transportation of gases and water.

Pipe of polyethylene having improved mechanical properties

Process for preparing a poly-1-olefin By means of a highly active spherical Ziegler catalyst based on a dialkylmagnesium, spherical polymers can be obtained in the polymerization of alpha-olefins. A further advantage of the catalyst of the invention lies in the high catalyst activity, so that only very small amounts of the catalyst are required for the polymerization. The residual titanium and/or zirconium content in the polymers prepared according to the invention is less than 10 ppm. Owing to its good responsiveness to hydrogen, the catalyst is particularly suited to two-stage processes for preparing polymers having a broad bimodal molecular weight distribution. The replacement of sulfur-containing electron donors such as diethyl sulfite by alcohols such as ethanol leads to less odor problems and broadened opportunities for use of the polymer. Owing to the spherical shape of the particles and the associated very good flow behavior of the polymers and copolymers, considerable simplification and advantages in handling, drying and processing are achieved.

Process for preparing a poly-1-olefin

A process for the preparation of a polyolefin wax by polymerization or copolymerization of olefins or diolefins in suspension and in the presence of a catalyst. The process utilizes a metallocene and a cocatalyst, wherein the metallocene is a compound of the formula I ##STR1## in which M.sup.1 is a metal of group IVb, Vb or VIb of the Periodic Table of Elements, R.sup.1 and R.sup.2 are identical or different and are a hydrogen atom, a C.sub.1 -C.sub.10 -alkyl group, a C.sub.1 -C.sub.10 -alkoxy group, a C.sub.6 -C.sub.10 -aryl group, a C.sub.6 -C.sub.10 -aryloxy group, a C.sub.2 -C.sub.10 -alkenyl group, a C.sub.7 -C.sub.40 -arylalkyl group, a C.sub.7 -C.sub.40 -alkylaryl group, a C.sub.8 -C.sub.40 -arylalkenyl group or a halogen atom and R.sup.3 and R.sup.4 are identical or different and are a mononuclear or polynuclear hydrocarbon radical which may form a sandwich structure with the central atom M.sup.1, low-boiling hydrocarbons having 3 or 4 carbon atoms or low-boiling halogenated hydrocarbons are used as suspending agents and the heat of reaction is removed by evaporative cooling.

Process for the preparation of polyolefin waxes

Organic substrate surfaces, particularly of industrial polymers, are provided by fluorination or chlorination with corresponding layers so as to obtain certain properties; for the purpose of improving the application of a layer, the surfaces are exposed beforehand at temperatures between 25.degree. C. and 300.degree. C. to hydrogen or a gas containing at least 0.1% by volume of hydrogen.

Process for conditioning organic substrate surfaces

A process for the preparation of a polyolefin wax by polymerization or co-polymerization of olefines or diolefins at a temperature of -40.degree. to 100.degree. C. at a pressure of 0.5 to 120 bar, in suspension and in the presence of a metallocene catalyst and a co-catalyst, thereby producing wax products in solid form which may be easily separated from the suspending agent and the catalyst need not be separated off.

Process for the preparation of polyolefin waxes in the presence of a

A Ziegler catalyst in which the transition metal component has been prepared by reacting a transition metal compound of titanium, zirconium, vanadium or chromium with a gel-like dispersion of a magnesium alcoholate is used for the preparation of poly-1-olefins, in particular polyethylene. The co-catalyst used is an organoaluminum compound. The polymers are obtained in a high to very high yield, and it is possible to control the particle size distribution of the polymers.

Process for the preparation of a poly-1-olefin

A polyethylene molding composition which consists of 50 to 80% by weight of a HD polyethylene having a very broad bimodal molecular mass distribution and 20 to 50% by weight of a chemical LLD polyethylene or LD polyethylene gives pipes, plates and sheets which have very good long-term and low-temperature characteristics.

Polyethylene molding composition

For the homopolymerization of ethylene or for the copolymerization of ethylene with other 1-olefins, a catalyst is used which comprises a trialkylaluminum compound and the entire product from the reaction of a magnesium alkoxide which is dissolved, suspended or dispersed as a gel in an inert solvent, with a tetravalent transition-metal compound and an organoaluminum compound, washing with an inert solvent and reacting with a halogenated metal compound. A polymer having coarse particles and a high bulk density is obtained.

Process for the preparation of ethylene (co)polymers

If the transition metal component used in an olefin polymerization catalyst is the product of the reaction between a siloxane-substituted metallocene of titanium, zirconium or hafnium and a hydroxyl group-containing support material, for example silicon dioxide, these metallocene catalysts can be employed in existing polymerization plants which are designed for the suspension process.

Process for the preparation of a 1-olefin polymer

Polyolefin waxes are obtained in high yield by copolymerizing propylene with small amounts of other olefins in the presence of a catalyst composed of a metallocene of the formula I: ##STR1## and an alumoxane. The waxes are produced as compact, spherical particles having a narrow particle size distribution and high apparent density. In addition, the physical data of these waxes such as, for example, hardness, melting point, melt viscosity etc., are variable within wide limits. The polymer chains are noteworthy for a homogeneous and uniform structure, the comonomer units being predominantly arranged individually between polypropylene blocks.

Polypropylene wax and process for the production thereof

The invention relates to a process for the preparation of a heterogeneous metallocene catalyst component from a suitably substituted metallocene of the sub-group 4 of the Periodic Table of the Elements and from poly(methylhydrogensiloxane) under the concomitant action of a catalyst. The metallocene component and a suitable aluminoxane can be used as catalyst for the polymerization of 1-olefins, cyclic olefins, diolefins and cyclic diolefins.

Process for the preparation of a heterogeneous metallocene catalyst

Copolymers of ethylene and higher 1-olefins which are suitable for the manufacture of thin films, are preferably prepared in a two-step process, the first step yielding a polymer having a high molecular weight, the second step giving a polymer having a low molecular weight. The films obtained from these copolymers have improved mechanical properties as compared to films manufactured from known corresponding raw materials. The mechanical properties are furthermore uniform in longitudinal and in transverse direction.

Ethylene copolymers and their use for the manufacture of films

The concentration of organoaluminum compounds in their solutions can be determined quantitatively, even in a range of less than 10 mmols/dm.sup.3, when adding to the solution to be analyzed instantaneously an excess of reactant and when measuring the produced reaction heat.

Process for the quantitative analysis of  organoaluminum compounds in

For quantitative analysis of aluminum compounds containing Al--C-- and Al--H-- bonds in hydrocarbons the organo-aluminum compounds are decomposed with a lower alcohol and the excess alcohol is subjected to back titration with the solution of a colored compound of an alkali metal with a polynuclear aromatic hydrocarbon.

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Hattersheim am Main, Germany

Ludwig Bohm