The inversion polymerization process for producing polymers, and particularly vinyl resins or polymers, is known and has been described in British Pat. No. 748,727. The process described in the British patent comprises forming an initial conversion of monomer(s) to polymer of up to 20% by mass polymerization of the monomer(s) in the presence of a suitable polymerization catalyst. In this first portion of the reaction, the monomer is the continuous phase. Thereafter, sufficient water is added to the polymerization system or medium to cause a phase inversion wherein the water becomes the continuous phase forming a dispersion of the unpolymerized monomer(s) in the water. This aqueous dispersion or suspension is then polymerized to convert substantially all of the remaining monomer(s) to solid polymer. However, this process has a significant disadvantage in that polymer buildup or scale on the internal surfaces of the reactor or "poly" is excessive and necessitates cleaning thereof after each batch or run is made.
In U.S. Pat. No. 3,706,722, issued Dec. 19, 1972, there is described an inversion polymerization process for producing vinyl polymers having improved uniformity and porosity, size and structure. The patentees accomplish this objective by incorporating a nonionic, monomer-soluble surface active agent in the initial continuous monomer phase. While producing a more porous polymer, the polymer buildup on the internal surfaces of the reactor is still a serious problem and detracts from the use of said process on a commercial basis. This is particularly true when producing polymers and copolymers of vinyl chloride where the buildup problem and health hazards, due to exposure to vinyl chloride, are acute.
Accordingly, there is a great need to produce polymers having uniform porosity, size and structure by the inversion polymerization process which will substantially eliminate polymer buildup and the difficulties attendant thereto.