TWO-PART, CYANOACRYLATE/FREE RADICALLY CURABLE ADHESIVE SYSTEMS
Two-part cyanoacrylate/free radically curable adhesive systems demonstrating improved toughness are provided.
1 . 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 a (meth)acrylate-functionalized urethane resin having a backbone, at least a portion of which includes a urethane linkage formed from isophorane diisocyanate, 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.
2 . The composition of claim 1 , wherein the cyanoacrylate component comprises H 2 C═C(CN)—COOR, wherein R is selected from alkyl, alkoxyalkyl, cycloalkyl, alkenyl, aralkyl, aryl, allyl and haloalkyl groups.
3 . The composition of claim 1 , wherein the peroxide catalyst comprises perbenzoates.
4 . The composition of claim 1 , wherein the peroxide catalyst is t-butyl perbenzoate.
5 . The composition of claim 1 , wherein the (meth)acrylate-functionalized urethane resin is present in the second part.
6 . The composition of claim 1 , wherein the peroxide catalyst is present in an amount from about 0.01 percent to about 10 percent by weight, based on the cyanoacrylate component.
7 . The composition of claim 1 , wherein the free radical curable component is a (meth)acrylate component selected from the group consisting of polyethylene glycol di(meth)acrylates, tetrahydrofuran (meth) acrylates and di(meth)acrylates, hydroxypropyl (meth) acrylate, hexanediol di(meth)acrylate, trimethylol propane tri(meth)acrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, benzylmethacrylate, tetraethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, di-(pentamethylene glycol) dimethacrylate, tetraethylene diglycol diacrylate, diglycerol tetramethacrylate, tetramethylene dimethacrylate, ethylene dimethacrylate, neopentyl glycol diacrylate, trimethylol propane triacrylate, ethoxylated bisphenol-A (meth)acrylate, ethoxylated bisphenol-F (meth)acrylate, and methacrylate-functional urethanes.
8 . The composition of claim 1 , wherein the transition metal comprises a member selected from the group consisting of copper, vanadium, cobalt and iron.
9 . The composition of claim 1 , wherein the first part is housed in a first chamber of a dual chamber syringe and the second part is housed in a second chamber of the dual chamber syringe.
10 . The composition of claim 1 , wherein the second part further comprises at least one of a plasticizer and a filler.
11 . The composition of claim 1 , wherein the first part further comprises a toughener.
12 . The composition of claim 11 , wherein the toughener is a member selected from the group consisting of (a) reaction products of the combination of ethylene, methyl acrylate and monomers having carboxylic acid cure sites, (b) dipolymers of ethylene and methyl acrylate, (c) combinations of (a) and (b), (4) vinylidene chloride-acrylonitrile copolymers, (5) and vinyl chloride/vinyl acetate copolymer, (6) copolymers of polyethylene and polyvinyl acetate, and combinations thereof.
13 . The composition of claim 1 , wherein when disposed between two substrates spaced apart by about 1 mm, reaction products thereof demonstrating a drop impact strength of greater than twice that of reactions products thereof disposed between two substrates spaced apart by about 0 mm.
14 . The composition of claim 1 , wherein the (meth)acrylate-functionalized urethane resin having a backbone, at least a portion of which includes a urethane linkage formed from isophorane diisocyanate is made from hydroxyethyl(meth)acrylate, polyethylene glycol and isophorane diisocyanate.
15 . The composition of claim 1 , wherein the (meth)acrylate-functionalized urethane resin having a backbone, at least a portion of which includes a urethane linkage formed from isophorane diisocyanate is present in an amount of about 5 to about 60 percent by weight of the free radical curable component of the Part B composition.
16 . The composition of claim 1 , wherein cured reaction products of the composition demonstrate a greater drop impact strength on substrates bonded together in a 1 mm spaced apart relationship than on substrates bonded together in a 0 mm spaced apart relationship.