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US 5,349,049 AGranted
Method of production of polyvinyl chloride resin for paste processing
AssigneeNippon Zeon Co., Ltd.
InventorsMasaaki Nishina, Osamu Ozaki
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AssigneeNippon Zeon Co., Ltd.
InventorsMasaaki Nishina, Osamu Ozaki
Estimating the term…
A method of production of polyvinyl chloride resin for paste processing comprises recovering in 98% or more the polyvinyl chloride resin from an aqueous dispersion of the polyvinyl chloride resin for paste processing as aggregates by adding an organic fluid which is at most barely soluble in water and does not dissolve or swell the polyvinyl chloride resin to the aqueous dispersion in the presence of an aggregating agent, followed by separating the aggregated polyvinyl chloride resin particles from the aqueous phase of the aqueous dispersion. By the addition of the aggregating agent, dispersion of the resin particles into a medium is improved, fluidity of a sol thereof and the physical properties of molded articles formed therefrom are improved and blocking during the drying process is prevented.
In a method for the production of particulate polyvinyl chloride resin suitable for paste processing in which an aqueous polyvinyl chloride resin dispersion containing 10 to 70 parts of the polyvinyl chloride resin per 100 parts of the aqueous dispersion is separated from the aqueous phase and recovered, the improvement which comprises adding to the aqueous dispersion and mixing therewith at a temperature from 20.degree. to 50.degree. C. (a) an amount from 0.5 to less than 15 weight parts per 100 weight parts of resin in the aqueous dispersion of an organic fluid which is at most barely soluble in water and does not dissolve or swell the polyvinyl chloride resin and has a boiling point of at least 200.degree. C. and (b) an aggregating agent, prior to separating the particulate polyvinyl chloride resin from the aqueous phase of the aqueous dispersion.
Dependencies are inferred from the claim text.