One-component thermosetting epoxy adhesive with improved adhesion

A one-component thermosetting epoxy resin adhesive, comprising;

• a) at least one epoxy resin A of the formula (II)
• wherein:
• the substituents R′ and R″ independently of one another are either H or CH3, and
• the index s has a value of 0-0.2,
• the fraction of the epoxy resin A being from 20-70 wt.-%, based on the total weight of the one-component thermosetting epoxy resin adhesive;
• and
• b) at least one epoxy novolac EN of the formula
• wherein:
• R2=
• or CH2,
• R1=H or methyl, and
• z=0-7,
• the fraction of epoxy novolac EN being from 1-8 wt.-% based on the total weight of the one-component thermosetting epoxy resin adhesive;
• and
• c) at least one latent hardener B for epoxy resins;
• and
• d) optionally at least one accelerator C for epoxy resins;
• and
• e) at least at least one toughness improver D,
• the fraction of toughness improver D being from 5-40 wt.-%, based on the total weight of the one-component thermosetting epoxy resin adhesive;
• wherein the epoxy resin adhesive has a viscosity of 500 to 5000 Pas at 25° C., as determined oscillographically by means of a rheometer with a heatable plate when measured with a deformation 0.01 at 5 Hz.