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Preparation of Commercial Epoxy Resins

المؤلف:  A. Ravve

المصدر:  Principles of Polymer Chemistry

الجزء والصفحة:  p475-476

2026-02-10

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Preparation of Commercial Epoxy Resins

The earliest developed commercial epoxy resins were diglycidyl ethers of 4,40-isopropylidine diphenol (Bisphenol A) formed by reacting epichlorohydrin with the diphenol. The reaction sequences involve formations of alkoxide ions, followed by nucleophilic additions to the least hindered carbons :

This is followed by ring closures through internal displacement of chloride ions:

As explained in the discussion on phenoxy resins, a reaction of two moles of epichlorohydrin with one mole of the diphenol yields higher molecular weight by-products and only 10% of the diether:

where x = 1–10 To obtain high yields of the diether, the quantities of epichlorohydrin in the reaction mixtures must be doubled or tripled [131]. This can result in yields as high as 70%. Another advantage of a large excess of epichlorohydrin in the reaction mixtures is that it serves as a solvent [134]. A different route to the diglycidyl ethers is via Friedel–Craft reactions [135]:

The higher molecular weight resins that form in the presence of caustic result from reactions of glycidyl ethers with phenoxy anions:

The number of repeat units in the above resin is determined by the molar ratios of the reactants.