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A CONTINUOUS PROCESS FOR THE PREPARATION OF POLY(VINYL ACETATE) FOR POLY(VINYL ALCOHOL) PRODUCTION
A CONTINUOUS PROCESS FOR THE PREPARATION OF POLY(VINYL ACETATE) FOR POLY(VINYL ALCOHOL) PRODUCTION
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机译：连续生产用于生产聚乙烯醇的醋酸乙烯酯的连续过程
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摘要
An improved process for the continuous production of poly(vinyl alcohol) whichinvolves purifying poly(vinyl acetate) paste exiting from a polymerization reactor anddissolving the substantially pure poly(vinyl acetate) in a hydrolytic alcohol-containingsolvent for subsequent saponification to produce poly(vinyl alcohol). Poly(vinyl acetate)paste, containing poly(vinyl acetate), vinyl acetate, and solvent, is heated to atemperature above the glass transition temperature but below a temperature which willdegrade the. poly(vinyl acetate) and is fed into a flashing area of an extrudingdevolatilization device. Vinyl acetate and solvent are flashed through vent ports in theflashing area of the devolatilization device and can then be recycled to a polymerizationreactor, if desired. A substantially pure poly(vinyl acetate) melt, exiting the flashing area,is conveyed to a mixing area of the devolatilization device where it is mixed with ahydrolytic alcohol-containing solvent to form a solution for subsequent processing in asaponification unit.(Figure 1)
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