Emulsion polymerization process
AssigneeI.S.R. Holding SARL
InventorsJohn D. Moore, Alan A. J. Feast
Life of this patent
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Abstract
A process for reducing the residual monomer level of a polymer latex prepared by emulsion polymerization comprises exposing the latex in a separate vessel from that in which the main polymerization has been carried out to conditions under which free radicals are produced by a secondary catalyst added to the latex, the said catalyst being oil soluble or having an oil soluble component. In a preferred embodiment a polymer latex prepared by the emulsion polymerization of styrene alone or a mixture containing styrene having a residual styrene level not exceeding 0.1% based on latex volume may be obtained.
Claims12
A process for reducing the residual styrene monomer level of a polymer latex prepared by the emulsion polymerisation of styrene monomer alone, or of a monomeric mixture containing styrene monomer which polymerisation has been taken to a conversion of at least 90%, which comprises exposing the latex, in a separate vessel from that in which the main polymerisation has been carried out to conditions under which free radicals are produced by a secondary redox catalyst, said catalyst having two components, one of which is oil soluble, and at least one component of which is water soluble and is added to the latex, the only monomers in said separate vessel being those left over from said conversion and wherein the residual styrene is reduced to a level not exceeding 0.1% based on the latex volume.
A process for reducing the residual vinyl aromatic monomer level of a polymer latex prepared by the emulsion polymerisation of a vinyl aromatic monomer alone, or of a monomeric mixture containing a vinyl aromatic monomer which polymerisation has been taken to a conversion of at least 90% and there is present 0.5 to 5% of residual monomer in the latex which comprises exposing the latex in a separate vessel from that in which the main polymerisation has been carried out to conditions under which free radicals are produced by a secondary redox catalyst, said catalyst having two components, one of which is oil soluble, and at least one component of which is water soluble and is added to the latex, the only monomers in said separate vessel being those left over from said conversion and reducing the residual monomer to not over 0.1%.
Dependencies are inferred from the claim text.