Epoxy adhesive composition comprising a calcium salt and mannich base

A method of adhering to an oily metal substrate comprising applying a curable, structural epoxy adhesive composition to an oily metal substrate, wherein said curable, structural epoxy adhesive composition comprises two parts, the first part comprising:

• (a) an epoxy catalyst comprising:
• (i) a Ca.sup.+2 salt;
• and
• (ii) an epoxy polymerization catalyst having the structure of formula (I):
• ##STR3## wherein R.sup.1 is H or --CH.sub.3
• R.sup.2 is --CHNR.sup.5 R.sup.6 and R.sup.5 and R.sup.6 are independently selected from --CH.sub.3 or --CH.sub.2 CH.sub.3 ;
• R.sup.3 and R.sup.4 independently may be present or absent, when present R.sup.3 and R.sup.4 are --CHNR.sup.5 R.sup.6 and R.sup.5 and R.sup.6 are independently selected from --CH.sub.3 or --CH.sub.2 CH.sub.3 ;
• and
• (b) an amine curing agent;
• and
• the second part comprising an epoxy resin having an average epoxide functionality of greater than one and wherein the stoichometric amine to epoxy ratio of the amine curing agent to the epoxy resin is from 0.2 to 0.9 to 1 and wherein the adhesive composition has an overlap shear strength of at least 9 MPa and exhibits cohesive failure when said composition is applied to oily metal coupons having an emulsified draw lubricated coating weight of 1,500 mg/ft.sup.2, cured at room temperature for 24 hours, oven cured for 20 minutes at 163.degree. C., and then equilibrated to room temperature prior to measuring overlap shear strength as measured by the test method LAP SHEAR STRENGTH.