The epoxy resin mixture, which contains (a) an epoxy resin or a mixture of epoxy resins having an average epoxide content of from 4.4 to 5.0 equivalents/kg and an average epoxide functionality of greater than 2.0, (b) a novolak having a hydroxyl equivalent weight of from 90 to 120, from 0.8 to 0.95 hydroxyl equivalents of component (b) being present in the epoxy resin mixture per epoxide equivalent of component (a), (c) from 0.1 to 1% by weight, based on the amount of components (a) and (b), of a curing accelerator, (d) from 0.5 to 10% by weight, based on the amount of components (a) and (b), of a blowing agent which eliminates nitrogen above 100 DEG C with decomposition, (e) from 0.3 to 1% by weight, based on the total amount of the epoxy resin mixture, of an emulsifier, and optionally (f) foam modifiers, can be used to produce cured foams having a high proportion of closed cells, good long-term heat resistance and good compressive strength.
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