Claims
- 1. A process for polymerizing vinyl chloride in a thickened aqueous medium comprising:
- (a) charging vinyl chloride to a polymerization vessel equipped with agitation and cooling means;
- (b) charging a solution comprising at least one catalyst, at least one solvent, and optionally at least one secondary surfactant, wherein said solvent has a density equal to or less than vinyl chloride and said catalyst solution has a density less than 1.0 g/cc;
- (c) agitating the vinyl chloride and the catalyst solution to thoroughly mix the ingredients;
- (d) reducing or stopping said agitation such that non turbulent flow is achieved;
- (e) charge thickened water to the polymerization vessel through a port near the bottom of the vessel, said water being previously mixed with at least one dispersant capable of thickening said water;
- (f) forming in the polymerization vessel a bottom layer of thickened water and a top layer of vinyl chloride;
- (g) increasing the agitation such that the entire polymerization medium is emulsified;
- (h) conducting the polymerization of the vinyl chloride to form porous spherical shaped polyvinyl chloride resin particles, wherein said spherical shaped particles have an average shape factor greater than about 0.9 and a porosity greater than about 0.05 cc/g;
- (i) removing the polymerized resin from the reaction vessel.
- 2. A process of claim 1 wherein the water thickening dispersant is a lightly crosslinked interpolymer of acrylic acid.
- 3. A process of claim 2 wherein said secondary surfactant is at least one surfactant selected from the group consisting of polyethylene oxide containing surfactant and non-polyethylene oxide containing surfactant.
- 4. A process of claim 3 wherein said secondary surfactant is a blend of a polyethylene oxide containing surfactant and a non-polyethylene oxide containing surfactant.
- 5. A process of claim 4 wherein said polyethylene oxide containing surfactant is polyoxyethylene (20) sorbitan monooleate.
- 6. A process of claim 5 wherein said non-polyethylene oxide containing surfactant is selected from the group consisting of sorbitan trioleate, sorbitan tristearate, sorbitan monooleate, sorbitan monopalmitate, glycerol monooleate, glycerol monostearate, and triglycerol monooleate.
- 7. A process of claim 1 wherein said solvent in (b) is selected from the group consisting of an alcohol having at least 2 carbon atoms and a hydrocarbon.
- 8. A process of claim 7 wherein said solvent is isopropyl alcohol.
- 9. A process of claim 1 wherein said catalyst solution comprises at least one solvent, at least one catalyst and at least one secondary surfactant.
- 10. A process of claim 1 wherein at least one of said secondary surfactant(s) is premixed with the vinyl monomer prior to being charged into the polymerization vessel.
- 11. A process of claim 1 wherein in (b) the catalyst solution containing catalyst, solvent and optionally at least one secondary surfactant are premixed with said vinyl monomer prior to being added to the polymerization vessel.
Parent Case Info
This is a division of application U.S. patent application Ser. No. 06/846,163,filed Mar. 31, 1986, now U.S. Pat. No. 4,668,707.
US Referenced Citations (7)
Divisions (1)
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Number |
Date |
Country |
Parent |
846163 |
Mar 1986 |
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