| 摘要 |
PURPOSE:To obtain an epoxy resin of a low chlorine content, suitable as a sealing resin for electronic components, by adding an alkali to a solution formed by dissolving a chlorine-containing epoxy resin in a specified sulfoxide compound. CONSTITUTION:0.5-10mol, per mol of the chlorine in component A, of an alkali (e.g., NaOH) is added to a solution formed by dissolving a chlorine- containing epoxy resin (A) made from epichlorohydrin in a sulfoxide compound (B) of the formula [wherein R<1-2> are each a 1-6C alkyl, an (un)substituted aryl or an (un)substituted aralkyl, provided that R<1> and R<2> may be combined together to form a ring structure) in an amount to provide a weight ratio of 1:50-10:1, and the mixture is reacted at 10-180 deg.C. To the reaction solution, a solvent such as benzene or toluene is added, impurities are removed from this solution by filtration and/or water washing, and the epoxy resin is recovered by vacuum or steam stripping.
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