Preparation method of low-ash polyvinyl alcohol
The invention discloses a preparation method of low-ash polyvinyl alcohol, comprising the steps of alcoholysis by base catalysis and drying each unit, characterized by carrying out solid-liquid extraction on the dried polyvinyl alcohol, wherein the extractant used in solid-liquid extraction is an al...
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Format: | Patent |
Sprache: | chi ; eng |
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Zusammenfassung: | The invention discloses a preparation method of low-ash polyvinyl alcohol, comprising the steps of alcoholysis by base catalysis and drying each unit, characterized by carrying out solid-liquid extraction on the dried polyvinyl alcohol, wherein the extractant used in solid-liquid extraction is an alcohol-water solution, the molar ratio of alcohol to water in the alcohol-water solution is 3.5:1-12:1, and the weight ratio of polyvinyl alcohol to the extractant is 0.065-0.15:1. The polyvinyl alcohol (PVA) prepared by the method of the invention has an ash content of no higher than 0.08%, and unchanged alcoholysis degree. The invention is suitable for polyvinyl alcohol with different degrees of polymerization, and can satisfy the requirements of different varieties. |
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