METHOD FOR PRODUCING AQUEOUS VINYL ESTER DISPERSIONS
The preparation of vinyl ester homo- or copolymers by emulsion polymerization is described. The process is performed in the presence of a polymerization-retarding component in at least two phases, the concentration of the vinyl ester monomer in the polymerization mixture in the first phase having be...
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Format: | Patent |
Sprache: | eng ; fre ; ger |
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Zusammenfassung: | The preparation of vinyl ester homo- or copolymers by emulsion polymerization is described. The process is performed in the presence of a polymerization-retarding component in at least two phases, the concentration of the vinyl ester monomer in the polymerization mixture in the first phase having been depleted by not more than 50% at the end of the first phase compared to the concentration of the vinyl ester monomer in the polymerization mixture at the start of the first phase, and the concentration of the vinyl ester monomer in the polymerization mixture in the second phase being depleted compared to the concentration at the end of the first phase. The retarding component is depleted during the first phase. In the second phase, the heat of reaction is removed by evaporative cooling. In the first phase, the emulsion polymerization is effected at temperatures up to the boiling point of the vinyl ester-water azeotrope, and, in the second phase, at temperatures above the boiling point of the vinyl ester-water azeotrope. The process is notable for a short cycle time and high space-time yields and can be operated safely. |
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