STRUCTURAL ADHESIVE COMPOSITIONS
Disclosed herein are compositions including (a) a first component comprising (1) an epoxy-adduct that is the reaction product of reactants comprising a first epoxy compound, a polyol, and an anhydride and/or a diacid and (2) a second epoxy compound; (b) rubber particles having a core/shell structure and/or graphenic carbon particles; and (c) a second component that chemically reacts with the first component at ambient or slightly thermal conditions. Also disclosed herein are compositions including (a) an epoxy-capped flexibilizer; (b) a heat-activated latent curing agent; and optionally (c) rubber particles having a core/shell structure and/or graphenic carbon particles; (d) an epoxy/CTBN adduct; and/or (e) an epoxy/dimer acid adduct. The heat-activated latent curing agent may include at least one reaction product of reactants including an epoxy compound and an amine and/or an alkaloid.
1 . A composition comprising:
(a) an epoxy-capped flexibilizer; and
(b) a heat-activated latent curing agent comprising a reaction product of reactants comprising (i) an epoxy compound, and (ii) an amine and/or an alkaloid.
2 . The composition of claim 1 , wherein the epoxy-capped flexibilizer comprises a reaction product of reactants comprising:
(i) an epoxy compound;
(iii) a polyol; and
(iv) an anhydride and/or a diacid.
3 . The composition of claim 1 , wherein the epoxy-capped flexibilizer comprises a reaction product of reactants comprising:
(i) an epoxy compound;
(iii) a polyol;
(iv) an anhydride; and
(v) a diacid.
4 . The composition of claim 1 , wherein the epoxy-capped flexibilizer comprises a reaction product of reactants comprising:
(i) an epoxy compound;
(ii) an anhydride and/or a diacid; and
(iii) a caprolactone.
5 . The composition of claim 1 , wherein the epoxy-capped flexibilizer comprises a reaction product of reactants comprising:
(i) an epoxy compound; and
(ii) a primary or secondary polyether amine.
6 . The composition of claim 1 , wherein the reactants comprise an amine.
7 . The composition of claim 1 , wherein the reactants comprise an alkaloid.
8 . The composition of claim 1 , wherein the reactants comprise an epoxy compound, an amine, and alkaloid.
9 . The composition of claim 1 , wherein the reactants comprise two epoxy compounds, an amine, and alkaloid.
10 . The composition of claim 1 , wherein the epoxy compound used as a reactant comprises Bisphenol A diglycidyl ether, phenyl diglycidyl ether, glycidyl methalcrylate, or combinations thereof.
11 . The composition of claim 1 , wherein the amine comprises secondary amine.
12 . The composition of claim 1 , wherein the amine comprises a dimethyl amine.
13 . The composition of claim 1 wherein the alkaloid comprises a diazole.
14 . The composition of claim 1 wherein the alkaloid comprises an imidazole.
15 . The composition of claim 1 further comprising (c) graphenic carbon particles, rubber particles having a core/shell structure, an epoxy/CTBN adduct and/or an epoxy/dimer acid adduct.
16 . The composition of claim 1 further comprising (c) dicyandiamine and/or 3,4-dichlorophenyl-N,N-dimethylurea.
17 . The composition of claim 1 , wherein the composition is curable at a temperature below 140° C.
18 . The composition of claim 1 , wherein the composition is heat-curable within 15 minutes or less.
19 . A method of adhering articles comprising:
(a) applying the composition of claim 1 to at least one of the articles; and
(b) heating the composition at a temperature of less than 140° C. for a time of less than 15 minutes to cure the composition and thereby adhering the articles together.
20 . The composition of claim 1 , which, when applied at 1 mm thick to hot dipped galvanized metal with a bond area of 20 mm×10 mm×0.25 mm, and following heating, has a measured lap shear strength of at least 15 MPa when tested at room temperature.