Two-part, cyanoacrylate/free radically curable adhesive systems

A two-part curable composition comprising:

• (a) a first part comprising a cyanoacrylate component and a peroxide catalyst;
• and
• (b) a second part comprising a free radical curable component and a transition metal, wherein at least one of the first part or the second part further comprises from 2 percent by weight to 20 percent by weight in the part of a core-shell impact modifier comprising a polymeric core and at least two polymeric layers surrounding the core,
• wherein the core-shell impact modifier is a particle having a particle size between 170 and 350 nm and a pH between 6 and 7.5 comprising one polymeric rubber core comprising at least partially crosslinked isoprene or butadiene and optionally styrene, and at least two polymeric layers wherein at least one polymeric layer is an outermost thermoplastic shell layer having a Tg greater than 25° C., each layer having a different polymer composition and,
• wherein at least one polymeric layer comprises a polymer that is a gradient polymer, the gradient polymer being a copolymer consisting of at least two different monomers (A) and (B) and having a gradient in repeat units arranged from mostly the monomer (A) to mostly the monomer (B) along the copolymer, and wherein when mixed together the peroxide catalyst initiates cure of the free radical curable component and the transition metal initiates cure of the cyanoacrylate component.