The Malaysian Rubber Producers Research Association

Andrew J Tinker

David S Campbell

David E Loeber

Carl L Riddiford

Ian R Gelling

Peter G Mente

The elastoplastic composition comprises a blend of a thermoplastic polyolefin resin, such as polypropylene, and vulcanized epoxidized natural rubber and has good oil resistance without the use of nitrile rubber and has good mechanical properties without the need for compatibilizing agents. The elastoplastic composition may be prepared by a method which comprises mixing the thermoplastic polyolefin resin and epoxidized natural rubber at a temperature sufficient to soften or melt the resin to give an intimate blend, then while continuing mixing, adding curative for the rubber and vulcanizing the epoxidized natural rubber at a vulcanization temperature.

Elastoplastic compositions

A hydroxyl-functional polymer is reacted with a compound ZCO.N(H).sub.x.N(H).sub.x.CO.OR, where Z is halogen or aryloxy, x is 0 or 1 and R is hydrocarbon, and the reaction product is if necessary oxidized to give an azodicarboxylate functional polymer having the formula QOCO.N:N.CO.OR where Q is an inert polymer group. This polymer is used to react with ethylenically unsaturated natural or synthetic rubber so as to graft groups derived from the polymer on the rubber backbone.

Reagents for graft copolymers

Graft copolymers having thermoplastic elastomeric properties are formed by intimately blending together at elevated temperature in the solid state in e.g. an internal mixer (a) an ethylenically unsaturated natural or synthetic rubber and (b) a pre-polymer of a vinyl aromatic monomer having an azodicarboxylate end group reactive towards unsaturated groups of the rubber.

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Hertford, United Kingdom

Andrew J Tinker