Akzona Incorporated

Jan D Van Drumpt

Wilhelmus M Beijleveld

Reinder Torenbeek

Gerrit Frits Drost

There is disclosed an improved process for cross-linking polymers by contacting said polymers with a cross-linking agent at an elevated temperature. The improvement comprises using as the cross-linking agent a compound of the formula ##STR1## wherein R.sub.1 and R.sub.2 are independently selected from the group consisting of alkyl groups having 1-22 carbon atoms, alkenyl groups having 2-22 carbon atoms, cyclohexyl groups having 6-20 carbon atoms, phenyl groups having 6-20 carbon atoms, aralkyl groups having 7-20 carbon atoms, alkyloxy groups having 1-22 carbon atoms, alkenyloxy groups having 2-22 carbon atoms, and cyclohexyloxy groups having 6-20 carbon atoms, all of which groups may be substituted or unsubstituted; R.sub.3 is selected from the group consisting of hydrogen, alkyl groups having 1-22 carbon atoms, alkenyl groups having 2-22 carbon atoms, cyclohexyl groups having 6-20 carbon atoms, phenyl groups having 6-20 carbon atoms, aralkyl groups having 7-20 carbon atoms, and ##STR2## wherein R.sub.4 is independently selected from the same group as R.sub.1 and R.sub.2 as defined above, all of which groups may be substituted or unsubstituted; provided that when R.sub.3 is hydrogen, R.sub.1 represents an alkyloxy, alkenyloxy or cyclohexyloxy group as defined above.

Process for cross-linking polymers

This disclosure relates to an improved process for initiating radical reactions employing a class of hydroximic acid derivatives as initiators. Radical reactions initiated by such hydroximic acid derivatives include copolymerization of unsaturated polyester resins and cross-linking of polyethylene. The initiators of the present disclosure have a higher degradation temperature than found with typical peroxides.

Process for initiating radical reactions employing hydroximic acid

A process for the preparation of an organic peroxide master batch comprising about 20-60% by weight of an organic peroxide and about 40-80% by weight of a polymer capable of being cross-linked by the peroxide, is disclosed. The process comprises contacting particles of such a polymer, having a diameter from about 200 microns to about 20 millimeters, at a temperature from about 15.degree. C. to about 95.degree. C., with a liquid medium which is not a physically stable emulsion and which comprises from about 2 to about 100 percent, by weight, of a peroxide which is a liquid at said temperature and from about 0 to about 98 percent, by weight, of a suitable liquid in which the peroxide and the polymer are insoluble, for a period of time sufficient to incorporate from about 20 to about 60 percent of peroxide in the polymer particles, based on the total weight of the polymer particles containing the peroxide, said medium being present in such an amount that after the incorporation of the peroxide essentially all of the polymer particles are completely surrounded by the liquid medium.

Process for preparing peroxide master batches

A non-polar synthetic resin is mixed with an organic peroxide and cross-linked with a high frequency alternating current field. The peroxide is a perketal or perester of the formula 1, 1a, 2, 3, 4 or 5 of the drawing. The cross-linked resin is useful for the insulation of an electrical conductor.

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Deventer, Netherlands

Jan D Van Drumpt