Two-part adhesive including toughened curative
A two-part adhesive is provided comprising: A) a curative part comprising: i) an epoxy curative; and ii) a reaction intermediate which is the reaction product of a suspension of core/shell rubber nanoparticles in a liquid epoxy resin and an excess of the epoxy curative; wherein the curative part comprises greater than 1.1 wt % core/shell rubber nanoparticles; and B) an epoxy part comprising: iii) a liquid epoxy resin; and iv) greater than 9.1 wt % core/shell rubber nanoparticles. In some embodiments, the epoxy part additionally comprises greater than 5.1 wt % solid epoxy resin, such as, e.g., triglycidyl ether of trisphenol-methane. In some embodiments, the sum of the wt % solid epoxy resin and the wt % core/shell rubber nanoparticles in the epoxy part is greater than 41.0%. In some embodiments, the sum of the wt % solid epoxy resin and the wt % core/shell rubber nanoparticles in the mixed adhesive is greater than 26.0%.
1. A two-part adhesive composition comprising:
A) a curative part comprising: i) an epoxy curative; and ii) a reaction intermediate;
wherein the reaction intermediate ii) is a reaction product of a suspension of core/shell rubber nanoparticles in a liquid epoxy resin and an excess of the epoxy curative;
wherein the core/shell rubber nanoparticles are present in an amount of greater than 1.1 wt % and less than 49 wt % of the curative part; and
B) an epoxy part comprising: iii) at least one liquid epoxy resin; and iv) core/shell rubber nanoparticles or a suspension of core/shell rubber nanoparticles in a liquid epoxy resin;
wherein the at least one liquid epoxy resin iii) is distinct from the liquid epoxy resins of ii) and iv);
wherein the core/shell rubber nanoparticles are present in an amount of greater than 9.1 wt % and less than 23.8 wt % of the epoxy part; and
wherein the curative part A) and the epoxy part B) are provided in a mixing ratio such that when mixed, the core/shell rubber nanoparticles of A) and B) are present in a combined amount of greater than 11.1 wt % and less than 49 wt % of the two-part adhesive composition.
2. The two-part adhesive composition according to claim 1 wherein the core/shell rubber nanoparticles of the curative part A) are present in an amount of greater than 6.1 wt % and less than 49 wt % of the curative part.
3. The two-part adhesive composition according to claim 1 wherein the epoxy part B) further comprises a solid epoxy resin, wherein the solid epoxy resin is present in an amount of greater than 5.1 wt % and less than 49 wt % of the epoxy part.
4. The two-part adhesive composition according to claim 3 wherein the solid epoxy resin is present in an amount of greater than 26 wt % and less than 49 wt % of the epoxy part.
5. The two-part adhesive composition according to claim 3 wherein the solid epoxy resin and the core/shell rubber nanoparticles of the epoxy part B) are present in a combined amount of greater than 41.0% wt % and less than 69 wt % of the epoxy part.
6. The two-part adhesive composition according to claim 3 wherein the curative part A) and the epoxy part B) are provided in a mixing ratio such that when mixed, the solid epoxy resin and the core/shell rubber nanoparticles of A) and B) are present in a combined amount of greater than 26.0% wt % and less than 59 wt % of the two-part adhesive composition.
7. The two-part adhesive composition according to claim 3 wherein the solid epoxy resin is triglycidyl ether of trisphenol-methane.
8. The two-part adhesive composition according to claim 1 wherein the epoxy curative i) is an amine epoxy curative.
9. A cured material that results from mixing the curative part A) with the epoxy part B) of the two part-adhesive composition according to claim 1 and allowing cure.