An adhesive composition is disclosed. The adhesive composition comprises an epoxy-containing component; rubber particles having a core-shell structure; and a curing component comprising a mixture of an amine-containing compound substantially free of hydroxyl functional groups and a polymeric phenol-containing compound, wherein the amine-containing compound comprises primary and/or secondary amino groups, and wherein the curing component chemically reacts with the epoxy-containing component upon activation from an external energy source. Also disclosed are methods of preparing the adhesive composition and for forming a bonded substrate with the adhesive composition. Further disclosed are curing components for an adhesive composition and methods of making the curing components.