| 摘要 |
PROBLEM TO BE SOLVED: To obtain a liquid epoxy resin having excellent thermal stability and a low viscosity by preparing a specific epoxy resin. SOLUTION: There is provided an epoxy resin of formula I. In formula I, R is H or a 1-4C alkyl; and G is glycidyl. This epoxy resin exhibits a lower viscosity (80 cps at 25 deg.C) and better workability compared with the conventional bisphenol A type epoxy resins having a viscosities around 13,000 cps at 25 deg.C, and gives a cured product excellent in thermal resistance and toughness. The epoxy resin can be obtained, for example, by reacting at a temperature of 20-120 deg.C a compound represented by formula II with an excess of an epihalohydrin such as epichlorohydrin, epibromohydrin or the like while or after adding an alkali metal hydroxide such as sodium hydroxide, potassium hydroxide or the like to a dissolved mixture of the reactants. In this reaction, if necessary, a quaternary ammonium salt can be added as a catalyst and an aprotic polar solvent can be added to effect the reaction smoothly.
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