Process for shortstopping an emulsion polymerization
AssigneeShell Oil Company
InventorsSijtske M. De Vries, Johannes A. M. Willemsen
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Abstract
A process for shortstopping a free radical polymerization of a conjugated diene and optionally a vinyl-substituted aromatic in an aqueous emulsion, using a hydroperoxide as initiator and a redox activator, comprising a divalent transition metal, a reducing agent and optionally being carried out in the presence of a modifier, and being performed by using as sole shortstopping agent an alkali metal polysulphide. This process results in the production of polymeric products which are free of carcinogenic nitrosamines.
Claims23
A process for shortstopping a free radical polymerization of a conjugated diene comprising:
- conducting the polymerization in an aqueous emulsion at a temperature of from about -20.degree. C. to about 70.degree. C.;
- using hydroperoxide as an initiator, and a redox activator system comprising a divalent transition metal, and a reducing agent;
- and
- in the presence of a sole shortstopping agent essentially consisting of an alkali metal polysulphide in an amount of from at least 0.07 parts by weight per hundred parts by weight of the total monomer initially charged to the polymerization system.
A process as in claim I, wherein the shortstopping agent is used in an amount of from 0.02 to 0.5 parts by weight per hundred parts by weight of the total monomer.
Dependencies are inferred from the claim text.