Catalytic devulcanization of rubber
AssigneeAlberta Research Council
InventorsRichard Anthony McFarlane, Roger Kai Lott, Haibo Huang
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Abstract
The present invention relates generally to the delulcanization of rubber. More specifically, the present invention relates to a process for the hydro-devulcanization of vulcanized rubber utilizing a rubber swelling solvent, a source of reactive hyrogen and elevated temperature and, optimally, also uses a dispersed molecular-scale hydrogenation catalyst that is introduced into the vulcanized rubber in a catalytically inert form that is soluable in the rubber swelling solvent.
Claims31
A process for the devulcanization of rubber comprising the steps of:
- a) contacting vulcanized rubber with a rubber-swelling solvent capable of swelling the rubber to form solvent-swollen vulcanized rubber;
- b) heating the solvent-swollen vulcanized rubber in the presence of a hydrogen source to initiate a devulcanzation reaction;
- and,
- c) allowing the devulcanization reaction to proceed for a time sufficient to effectively devulcanize the vulcanized rubber
- wherein step a) includes contacting vulcanized rubber with a hydrogenation catalyst precursor dissolved in the rubber-swelling solvent to form solvent-swollen vulcanized rubber containing the hydrogenation catalyst precursor;
- and step b) includes heating the solvent-swollen vulcanized rubber to convert the catalyst precursor to an active catalyst in the presence of the hydrogen source to initiate the devulcanzation reaction.
A process for devulcanizing rubber comprising contacting and heating an amount of vulcanized rubber with an effective amount of a rubber swelling solvent and a hydrogenation catalyst precursor soluble in the solvent.
A monophasic devulcanization solution comprising a hydrogenation catalyst precursor and a rubber swelling solvent.
A rubber-swelling solvent and an organo-transition metal catalyst precursor in solution for use in the devulcanization of vulcanized rubber in an anaerobic environment in the presence of a hydrogen source.
A rubber devulcanization process comprising the steps of:
- a) contacting vulcanized rubber with a mixture of a hydrogenation catalyst precursor and a rubber swelling solvent;
- b) activating the hydrogenation catalyst precursor with heat and a source of sulphur to cause devulcanization in the presence of reactive hydrogen.
A rubber devulcanization process comprising the steps of converting a catalyst precursor, M-Rx, where M is a transition metal and Rx is an organic or other ligand capable of coordination with the transition metal in a charged or uncharged state, to an active catalyst by reaction of the catalyst precursor with sulphur within solvent-swollen vulcanized rubber, R′—Sz—R″, where R′ and R″ are rubber polymers or rubber polymer additives and —Sz— are sulphur crosslinks within the vulcanized rubber and wherein the reaction is carried out in the presence of reactive hydrogen.
Dependencies are inferred from the claim text.