One-component epoxy-modified polyurethane and/or polyurea adhesives having high elongation and excellent thermal stability, and assembly processes using same

1. A one-component epoxy-modified polyurethane and/or urea adhesive comprising in admixture:

components A and B, wherein component A) is one or more non-rubber-modified epoxy resins and component B) is one or more rubber-modified epoxy resins;

C) one or more reactive urethane group- and/or urea group-containing tougheners having a number average molecular weight of up to 35,000, at least one polyether or diene rubber segment having a weight of at least 1000 atomic mass units, and capped isocyanate groups of which at least 75% are monophenol- or polyphenol-capped isocyanate groups;

D) optionally, one or more core-shell rubbers;

E) one or more latent epoxy curing agents; and

F) at least one catalyst for the reaction of an epoxide with the curing agent(s); wherein

1) component A constitutes 10 to 25 percent of the combined weight of components A-E;

2) component B constitutes 2 to 30 percent of the combined weight of components A-E;

3) components A and B together constitute 12 to 40 percent of the combined weight of components A-E;

4) component C constitutes 55 to 85 percent of the combined weight of components A-E;

5) components B, C and D together constitute 65 to 85 percent of the combined weight of components A-E;

6) component D constitutes 0 to 15 percent of the combined weight of components A-E; and

7) components A-E together constitute at least 60 weight percent of the one-component epoxy adhesive.

2. The adhesive of claim 1 , wherein component C constitutes 60 to 80 percent of the combined weight of components A-E.

3. The adhesive of claim 1 , wherein component B includes at least one epoxy-terminated polyether.

4. The adhesive of claim 3 wherein component A includes at least one diglycidyl ether of a bisphenol.

5. The adhesive of claim 1 , wherein the catalyst includes at least one imidazoline catalyst having the structure:

where n is 2 or 3.

6. A method for bonding two substrates, comprising forming a layer of the adhesive of claim 1 at a bondline between two substrates to form an assembly, and then curing adhesive layer at the bondline by heating to a temperature of at least 160° C., to form a cured adhesive bonded to the two substrates at the bondline.

7. The method of claim 6 , wherein the two substrates have coefficients of linear thermal expansion that are different from each other by at least 5×10 −6 m/m-K.

8. The method of claim 7 , wherein one of the substrates is a metal and the other substrate is a thermoplastic organic polymer, a thermoset organic polymer or a fiber composite.

9. A method for forming a bonded and coated assembly, comprising 1) forming a layer of the adhesive of claim 1 at a bondline between a first and a second substrate to form an assembly that includes the first and second substrates each in contact with the adhesive composition at the bondline; then

2) immersing the assembly into a coating bath to form a layer of an uncured coating on at least a portion of the exposed surface of the assembly; and

3) heating the assembly to a temperature of at least 160° C. to cure the adhesive to form a cured adhesive bonded to the substrates at the bondline and simultaneously cure the coating layer.

10. The method of claim 9 , wherein the first and second substrates have coefficients of linear thermal expansion that are different from each other by at least 5×10 −6 m/m-K.

11. The method of claim 10 , wherein one of the substrates is a metal and the other substrate is a thermoplastic organic polymer, a thermoset organic polymer or a fiber composite.