Patent ID: 11958938
Assignee: 3M INNOVATIVE PROPERTIES COMPANY
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C | IPC C

Claim 0:
1. A method of making a curative part of a two-part curable composition, the method comprising:
combining a dispersion of core-shell rubber particles in an epoxy resin, a heterogeneous dispersant that is a solid thixotropic agent, and a liquid amine to provide a mixture; wherein the core-shell rubber particles have an elastomeric core, a (meth)acrylic shell, and a median particle size of from 20 nanometers to 1000 nanometers; and
shearing the mixture with a rotary high-shear impeller at temperatures from 25° C. to 90° C. until the core-shell rubber particles are dispersed into the liquid amine, thereby providing a curative part capable of being reacted with a base part comprised of an epoxy resin;
wherein the liquid amine and the epoxy resin of the dispersion are reacted before or after said shearing to provide a reactive precursor having an increased amine equivalent weight, which increases the viscosity of the curative part and mitigates amine blushing;
wherein the curative part is phase-stable over a period of at least 3 months at ambient temperature, and
wherein the curative part comprises from 5% to 30% by weight of the core shell rubber particles, from 0.05% to 20% by weight of the heterogeneous dispersant, and from 10% to 90% by weight of the liquid amine, relative to the overall weight of the curative part.