Recirculating a portion of high internal phase emulsions prepared in a continuous process

A continuous process for the preparation of a high internal phase emulsion, which process comprises:

• A) providing a liquid oil phase feed stream comprising an effective amount of a water-in-oil emulsifier;
• B) providing a liquid water phase feed stream;
• C) simultaneously introducing the liquid feed streams into a dynamic mixing zone at flow rates such the initial weight ratio of water phase to oil phase is in the range from about 2:1 to about 10:1;
• D) subjecting the combined feed streams in said dynamic mixing zone to sufficient shear agitation to at least partially form an emulsified mixture in said dynamic mixing zone;
• E) continuously withdrawing the emulsified mixture from said dynamic mixing zone;
• F) recirculating from about 10 to about 50% of the withdrawn emulsified mixture to said dynamic mixing zone prior to step (D);
• G) continuously introducing the remaining withdrawn emulsified mixture into a static mixing zone wherein the remaining emulsified mixture is further subjected to sufficient shear mixing to completely form a stable high internal phase emulsion having a water to oil phase weight ratio of at least about 4:1;
• and
• H) continuously withdrawing from the dynamic mixing zone the portion of the stable high internal phase emulsion that is not recirculated in step (F);
• wherein at any time subsequent to step D), the flow rate of the oil phase stream, the water phase stream, or both may be altered to modify the weight ratio of water phase to oil phase.

A continuous process for the preparation of a high internal phase emulsion capable of forming a polymeric foam material, which process comprises:

• A) providing a liquid oil phase feed stream comprising:
• 1) from about 80 to about 97% by weight of a monomer component capable of forming a polymer having a Tg of about 35.degree. C. or lower and comprising:
• a) from about 50 to about 70% by weight of a monomer selected from the group consisting of isodecyl acrylate, n-dodecyl acrylate and 2-ethylhexyl acrylate, and mixtures thereof:
• b) from about 15 to about 30% by weight of the comonomer selected from the group consisting of styrene, ethyl styrene and mixtures thereof;
• and
• c) from about 15 to about 25% by weight of a crosslinking agent selected from the group consisting of divinyl benzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, 2-butenediol dimethacrylate, ethylene glycol diacrylate, trimethylolpropane triacrylate and trimethacrylate, and mixtures thereof;
• and
• 2) from about 3 to about 20% by weight of an emulsifier component comprising an emulsifier selected from the group consisting of sorbitan monoesters of branched C.sub.16 -C.sub.24 fatty acids, linear unsaturated C.sub.16 -C.sub.22 fatty acids, and linear saturated C.sub.12 -C.sub.14 fatty acids;
• diglycerol monoesters of branched C.sub.16 -C.sub.24 fatty acids, linear unsaturated C.sub.16 -C.sub.22 fatty acids, and linear saturated C.sub.12 -C.sub.14 fatty acids;
• diglycerol monoaliphatic ethers of branched C.sub.16 -C.sub.24 alcohols, linear unsaturated C.sub.16 -C.sub.22 alcohols, and linear saturated C.sub.12 -C.sub.14 alcohols;
• and mixtures thereof
• B) providing a liquid water phase feed stream comprising an aqueous solution containing from about 0.2% to 20% by weight of water-soluble electrolyte and an effective amount of a polymerization initiator;
• C) simultaneously introducing the liquid feed streams into a dynamic mixing zone at flow rates such the initial weight ratio of water phase to oil phase is in the range from about 2.5:1 to about 5:1;
• D) subjecting the combined feed streams in said dynamic mixing zone to sufficient shear agitation to at least partially form an emulsified mixture in said dynamic mixing zone;
• E) continuously withdrawing the emulsified mixture from said dynamic mixing zone;
• F) recirculating from about 15 to about 40% of the withdrawn emulsified mixture to said dynamic mixing zone prior to step (D);
• G) subjecting the recirculated emulsion in the dynamic mixing zone to sufficient shear mixing to completely form a stable high internal phase emulsion having a water to oil phase weight ratio of from about 12:1 to about 250:1;
• and
• H) continuously withdrawing from the dynamic mixing zone the portion of the stable high internal phase emulsion that is not recirculated in step (F);
• wherein at any time subsequent to step D) the flow rate of the oil phase stream the water phase stream, or both may be altered to modify the weight ratio of water phase to oil phase.