Basf Aktiengesellschaft

Erich Haedicke

Hartmut Hibst

Arend Werner

Konrad Knoll

Klaus Bronstert

Johann Kronenbitter

A process for preparing bifunctional living polymers which are able to forth bifunctional telechelic polymers or block copolymers with at least 3 blocks of conjugated dienes and/or vinylaromatics with molecular weights of from 1,500 to 500,000, by bifunctional initiators whose anionic centers are aliphatic carbon atoms which are substituted by lithium and an aliphatic hydrocarbon radical as well as by either 2 aryl radicals or by one aryl radical and one hydrogen radical, where one of the aryl radicals can also be part of the two anionic centers, in a first stage being reacted in the presence of not more than 2.5 moles of an aliphatic ether or a tertiary amine per mole of lithium and not less than 2 mol/l of a conjugated diene at from -40.degree. to +35.degree. C. with not less than two moles of diene, resulting in the formation of low molecular weight diene oligomers which in turn act as bifunctional initiators, and using the latter in a second reaction stage in a conventional manner at above 40.degree. C., with or without the addition of other monomers, to obtain polymers of the required molecular weight.

Living polymers, the preparation thereof and the use thereof for

Magnetic recording media for perpendicular recording are produced by coating a non-magnetic substrate by a PVD method with a cobalt-containing, ferromagnetic metal layer which has magnetic anisotropy perpendicular to the plane of the layer, by a process in which the temperature of the substrate is increased by external heating during coating.

Production of magnetic recording media for perpendicular recording

Magnetic recording media essentially consisting of a disk-shaped aluminum substrate, a nonmagnetic (Ni-P) lower film, a chromium-containing intermediate film and a ferromagnetic metal film are produced by a process in which the surface of the (Ni-P) lower film is cleaned by RF sputter etching and then oxidized.

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Hirschberg, Germany

Erich Haedicke