Additive for epoxy adhesive and composition for structural epoxy adhesive comprising the same

An additive for an epoxy adhesive having a bottle brush structure, wherein the additive has a structure of a following Chemical Formula 1 including a core including a cyclic compound A and a shell connected to the core, wherein the cyclic compounds A are connected to each other via ROMP (Ring Opening Metathesis Polymerization):

• wherein in the Chemical Formula 1,
• A represents a substituted or unsubstituted cycloalkene, each of R1 and R2 independently represents substituted or unsubstituted C1 to C10 alkyl, alkyne, nitroxide, ester, ether, amine, substituted or unsubstituted C5 to C12 carbon ring, substituted or unsubstituted C3 to C12 heterocyclic ring, or a combination thereof,
• each of B and D independently represents C2 to C10 alkyl acrylate, C2 to C10 alkyl methacrylate, acrylic acid, glycidyl acrylate, glycidyl methacrylate, or ethylene glycol, wherein a case in which all of B and D are C2 to C10 alkyl acrylate, or C2 to C10 alkyl methacrylate is excluded, wherein p is an integer of 0 or 1 to 10, and each of n and m independently is an integer of 1 to 100.