METHOD FOR THE PREPARATION OF NOVOLAK EPOXY RESINS

A Novolak epoxy resin is prepared by adding an aqueous solution of alkali metal hydroxide to a solution of Novolak phenolic resin in epichlorohydrin, distilling off water during said addition in the form of an azeotrope with epichlorohydrin and recycling the latter, while maintaining the reaction me...

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Bibliographische Detailangaben
Hauptverfasser:	PITZALIS, MARIO, LAZZERINI, GIORGIO, VARGIU, SILVIO
Format:	Patent
Sprache:	eng ; fre
Schlagworte:	CHEMISTRY COMPOSITIONS BASED THEREON MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS METALLURGY ORGANIC MACROMOLECULAR COMPOUNDS THEIR PREPARATION OR CHEMICAL WORKING-UP
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Beschreibung
Zusammenfassung:	A Novolak epoxy resin is prepared by adding an aqueous solution of alkali metal hydroxide to a solution of Novolak phenolic resin in epichlorohydrin, distilling off water during said addition in the form of an azeotrope with epichlorohydrin and recycling the latter, while maintaining the reaction medium at 60-80.degree.C and at a pH between 7 and 8 and a water content of from 0.5 to 2.5 wt.% in said medium. The thermosetting resin thus obtained can be used in applications requiring resins with low chlorine contents, low viscosity and high epoxy value.