A flexible encapsulating material resulting from a mixture that includes at least one epoxy novolak resin and at least two other epoxy compounds wherein the material has a percent hardness change of less than 20% after thermal aging of 504 hours at 140° C. The epoxy novolak resin preferably has less than 3 epoxy groups per molecule. A further embodiment is an electronic component encapsulated with a flexible material resulting from combining a two part system wherein a first part includes an epoxy novolak resin and at least two other epoxy resins and the second part includes at least one amine. An additional embodiment is a method for flexibly encapsulating an electronic component comprising applying to the component a mixture comprising an epoxy novolak resin having less than 3 epoxy groups per molecule and at least one other epoxy compound.
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