Ruhrchemie Aktiengesellschaft

Hoechst Aktiengesellschaft

Josef Berzen

Jens Ehlers

Hans-Walter Birnkraut

Siegfried Lutze

Hermann Van Laak

Peter Schneller

Meinhard Gusik

Gunter Hetkamp

Herbert Mrozik

Johannes Theyssen

Polyethylene compositions for producing moldings have a surface resistance of at most 10.sup.9 .OMEGA. including

Polyethylene molding compositions

A boron-containing polyethylene having an average molecular mass of at least 2.5.times.10.sup.6 g/mol as a neutron-absorbing material.

Neutron-absorbing materials

There is disclosed a pile-driver comprising a cylinder and a piston, the piston being in registry with a cap disposed over an article to be driven. The cap has a lining in striking relationship with the piston, which lining comprises a thermoplastic and a metal powder.

Striking cap lining

A high molecular weight copolymer of ethylene and a C.sub.3 -C.sub.20 .alpha.-olefin which, after being molded at room temperature and pressure-free tempered at 120 to 250.degree. C. and thereafter cooled, provides molded articles having an ultimate tensile strength of more than 200 kg per square centimeter measured at 120.degree. C. and an impact strength of more than 200 kg cm/cm.sup.2 measured at 23.degree. C.; a process for the preparation of such a copolymer by a Ziegler catalysis which process is characterized in that the catalyst which is employed is one obtained by reducing a titanium-(IV)-halide with an organo-aluminum compound in an inert solvent such that the concentration of titanium-(III)-halide so formed amounts to 30 to 200 m mol/liter solvent, the C.sub.3 -C.sub.20 .alpha.-olefin is employed in an amount of 0.05 to 5 weight percent based upon the weight of the ethylene and the catalyst is either initially contacted with C.sub.3 -C.sub.20 .alpha.-olefin in the absence of ethylene and thereafter contacted with the ethylene or, is initially contacted with a mixture of C.sub.3 -C.sub.20 .alpha.-olefin and ethylene; and a catalyst for such polymerization.

Process for the manufacture of high molecular copolymerisates of ethylene

A process for the manufacture of a molded article from a powder form of a polyolefin of molecular weight of at least one million which comprises introducing a homopolymer of ethylene or a copolymer of ethylene with an .alpha.-olefin of 3 to 10 carbon atoms having a molecular weight of at least one million into a mold loosely closed with a plug, heating the same in said mold in an inert atmosphere at a temperature of 150.degree. to 250.degree. C, whereby said polyolefin is transformed into a rubbery elastic state, thereafter compressing said polyolefin in said mold for at least two minutes at a pressure of 2.5 to 25 N/mm.sup.2 and thereafter compressing said polyolefin for at least one minute at a pressure of 40 to 100 N/mm.sup.2.

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Oberhausen, Germany

Josef Berzen