2346372-A cites 4 patents.
There is a need for odorless rubbery polymers that offer high heat resistance, ultraviolet light resistance and low fogging characteristics. For instance, rubbery polymers of this type are needed by the automotive and construction industries. The deodorised rubbery polymers of this invention are of particular value because they can be blended with polyvinyl chloride to make leathery compositions having good heat and ultraviolet light resistance.; The present invention more specifically discloses a process for preparing a deodorised rubbery polymer which comprises the steps of (1) polymerizing in a first stage (a) butyl acrylate, (b) at least one member selected from the group consisting of methyl methacrylate, ethyl methacrylate, methyl acrylate and ethyl acrylate, (c) acrylonitrile and (d) a crosslinking agent under emulsion polymerisation conditions to produce a seed polymer containing latex, wherein said polymerization is initiated with a redox initiator system, wherein the redox initiator system is comprised of a free radical generator and a reducing agent; ; (2) adding (a) styrene, (b) additional acrylonitrile, (c) additional crosslinking agent and (d) additional free radical generator to the seed polymer containing latex under emulsion polymerisation conditions which result in the formation of an emulsion containing the rubbery polymer; and (3) recovering the rubbery polymer from the emulsion containing the rubbery polymer. Preferably the cross-linking agent is divinylbenzene, and the redox system is potassium persulfate as radical generator and sodium formaldehyde sulfoxylate as reducing agent.