Systems and methods for improved lap shear strength and displacement of two-component structural adhesives
Disclosed are systems for treating a substrate comprising a deoxidizing composition and a coating composition. The deoxidizing composition comprises a Group IVA metal and/or a Group IVB metal and free fluoride, optionally may comprise a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit, and has a pH of 1.0 to 3.0. The coating composition comprises first and second components and elastomeric particles. The first component comprises an epoxy-containing compound (E1) and/or an epoxide-functional adduct (E2). The second component comprises a diamine and/or a polyamine comprising a cyclic ring (A2) and/or an amine-functional adduct (A3). The present invention is also directed to methods of making the compositions, methods of coating a substrate, and coated substrates.
1 . A system for treating a substrate, comprising:
a deoxidizing composition comprising a Group IVA metal and/or a Group IVB metal and free fluoride, wherein the deoxidizing composition has a pH of 1.0 to 3.0; and
a coating composition comprising:
a first component comprising a first epoxy-containing compound; and
a second component that chemically reacts with the first epoxy-containing compound, the second component comprising an amine-functional adduct (A3) comprising a second reaction product of reactants comprising (a) a monoamine, diamine, and/or polyamine (A2) and (b) an epoxide-functional adduct (E2), wherein the epoxide-functional adduct (E2) comprises a first reaction product of reactants comprising (i) a second epoxy-containing compound (E1) and (ii) a diamine comprising a cyclic ring and/or a polyamine comprising a cyclic ring (A1).
2 . The system of claim 1 , wherein the deoxidizing composition further comprises (a) a Group IA metal, (b) a Group VIB metal, (c) an electropositive metal, and/or (d) a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and/or a non-phosphorous-containing monomeric subunit m2.
3 . A substrate treated with the system of claim 1 .
4 . The substrate of claim 3 comprising a coating formed from the coating composition, wherein the coating has a lap shear displacement of at least 2.5 mm at failure and a lap shear strength of at least 30.0 MPa, wherein the lap shear displacement and the lap shear strength each are measured according to ASTM D1002-10 using 2024-T3 aluminum substrate of 1.6 mm thickness, as measured by an INSTRON 5567 machine in tensile mode with a pull rate of 1.3 mm per minute.
5 . A method for treating a substrate, comprising: contacting at least a portion of a surface of the substrate with the deoxidizing composition of claim 1 ; and contacting at least a portion of the surface with the coating composition of claim 1 .
6 . The method of claim 5 , wherein the substrate is not contacted with a pretreatment composition following the contacting with the deoxidizing composition and prior to the contacting with the coating composition.
7 . A method of treating an extruded article with the system of claim 1 comprising:
extruding the coating composition of claim 1 ; and
applying the deoxidizing composition of claim 1 to at least a portion of a surface of the article.