Continuous process for producing rubbery polymer

Abstract

There is a need for polymers which are utilized in automotive interiors which offer increased heat and ultraviolet light resistance. It is particularly critical for polymers which are utilized in making skin compounds for automotive instrument and door panels to display excellent heat and ultraviolet light resistance. This invention discloses a continuous process for preparing a rubbery polymer which can be blended with polyvinyl chloride to make leathery compositions having good heat and ultraviolet light resistance. This technique involves utilizing a multiple continuous reactor system wherein a first phase monomer solution containing butyl acrylate, an acrylic monomer, acrylonitrile and a crosslinking agent is continuously charged into at least three initial reactors. To attain a small particle size, it is necessary to limit the solids content in each of these initial reactors. Then, a second phase monomer solution containing styrene, additional acrylonitrile and additional crosslinking agent is continuously charged into a subsequent reactor. This technique can also be utilized to synthesize core/shell or IPN structures by using multistage emulsion polymerization in which the first stage latex contains a majority of the butyl acrylate with a small latex particle size being obtained.