Siemens Aktiengesellschaft

Manfred Schmiedel

Wolfgang Von Gentzkow

Helmut Markert

Hans Hauschildt

Reinhold Tussing

A method for radical cross-linking or organic polymers, is disclosed which uses a cross-linking enhancer of the following formula ##STR1## wherein R is alkenyl or alkynyl;

Method for radical cross-linking of organic polymers

The invention relates to a method and apparatus for the manufacture of N,N'-bis-(aroyl)hydrazines from hydrazine and arylcarboxylic acid alkyl esters in the presence of catalysts. According to the invention, the reaction ingredients are reacted in a substantially stoichiometric mass ratio in an inert medium of low volatility which is liquid to wax-like under reaction conditions, in a suitable reactor equipped with a centrifugal disc and connected to a cycling, separating and draining-off system and a dispersion head to form a paste-like product. The paste-like compound can be used as a metal deactivator in polyolefin which is in direct contact with copper, for instance, in cable and wire insulation.

Method and apparatus for the manufacture of N,N'-bis-(aroyl)hydrazines

A method for stabilizing organic polymers against copper-catalyzed oxidative decomposition by means of N,N-bis-salicyloyl hydrazine as a metal deactivator is described wherein dust development of the metal deactivator is precluded with certainty and negative property changes of the stabilized organic polymers are avoided. For this purpose, it is provided that a paste which contains finely-crystalline N,N'-bis-salicyloyl hydrazine in fine distribution in a liquid to wax-like aliphatic hydrocarbon of low volatility is worked into the polymer. The method is particularly well suited for stabilizing polyolefins for cable and wire insulation.

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Nurnberg-Grossgrundlach, Germany

Manfred Schmiedel