Mixing of organosulfur molecular weight modifier with emulsifier for emulsion polymerization systems
AssigneePhillips Petroleum Company
InventorsCarl A. Uraneck, John E. Burleigh
Life of this patent
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Abstract
Organosulfur molecular weight regulators for emulsion polymerization systems, such as mercaptan compounds, are mixed and agitated with the aqueous emulsifier prior to use in emulsion polymerization systems. The modifying efficiency of the organosulfur molecular weight modifiers can be controlled by the degree of agitation. In many cases, adding the agitated mixture incrementally to the emulsion polymerization system further improves effectiveness of the modifier.
Claims26
In a process of aqueous emulsion polymerization wherein at least one polymerizable vinyl monomer polymerizable with a free radical initiator is polymerized under aqueous emulsion polymerization conditions in the presence of said free radical initiator, aqueous emulsifier solution, organosulfur compound as molecular weight modifier, and aqueous medium, the steps comprising:
- a. admixing at least a portion of said aqueous emulsifier with said organosulfur compound molecular weight modifier and coagitating the resulting admixture sufficiently to increase the regulating index of said modifier to produce a coagitated admixture prior to the introduction thereof into said emulsion polymerization process,
- b. admixing said coagitated admixture of said aqueous emulsifier and said organosulfur compound with said polymerizable vinyl monomer and initiator, and
- c. polymerizing the resulting polymerization admixture under aqueous emulsion polymerization conditions,
- wherein said emulsifier is an anionic or nonionic emulsifier;
- said organosulfur compound molecular weight modifier is a mercaptan, dialkyl dixanthogen, diaryl disulfide, tetraalkyl thiuram mono- or disulfide, or mercaptothiazole;
- and wherein said coagitation sufficient to increase the reactivity of said organosulfur compound as said modifier refers to strong and thorough mixing of organosulfur compound with aqueous emulsifier solution in a manner so as to afford a significant reduction in the particle size of said organosulfur compound in said emulsifier solution, and said coagitation is sufficient to effectuate a significant increase in said regulating index of said organosulfur compound when employed in said emulsion polymerization system.
Dependencies are inferred from the claim text.