| 摘要 |
The invention concerns a method of preparation of epoxy resins with low colouring prepared by condensation of dien with epichlorohydrin in a molar ratio of 1 : 1.4 to 1 : 10 with the help of hydroxide of alkaline metals, based on the fact that before the start of condensation by alkaline hydroxide, the initial reaction mixture, by boiling at normal or lowered pressure, is divested of dissolved oxygen and, in the course of actual condensation, an oxygen-free atmosphere is created above the reaction mixture either by vapours of volatile materials liberated by reactive boiling of the mixture at normal or preferably lowered pressure and/or by introduction of inert gas above the condensation mixture.
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