Two-part, cyanoacrylate/cationically curable adhesive systems

1. A two part curable composition comprising:

(a) a first part comprising a cyanoacrylate component and a cationic catalyst; and

(b) a second part comprising a cationic curable component and an additive to improve fixture time,

wherein when mixed together the cationic catalyst initiates cure of the cationic curable 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 cationic catalyst comprises salts of lithium and metals from Group II of the Periodic Table, and non-nucleophilic acids.

4. The composition of claim 1 , wherein the cationic catalyst is a non-nucleophilic acid having a pH of less than 1.0 when measured as a 10% by weight solution in water.

5. The composition of claim 1 , wherein the cationic catalyst is a member selected from the group consisting of fluoroboric, fluoroarsenic, fluoroantimonic and fluorophosphoric acids; lithium tetrafluoroborate, calcium di-tetrafluoroborate, magnesium di-tetrafluoroborate, lithum hexaflourophosphate, calcium di-hexaflourophosphate, magnesium di-hexaflourophosphate, lithium hexaflouroantimonate and lithium hexaflouroarsenate; lanthanide triflate salts, aryl iodonium salts, aryl sulfonium salts, lanthanum triflate, ytterbium triflate, trimethoxyboroxine, trimethoxyboroxine-aluminum acetyl acetonate, amine-boron trihalide complexes, quaternary ammonium salts, quaternary phosphonium salts, tri-aryl sulfonium salts, di-aryl iodonium salts, and diazonium salts; trialkoxyboroxine curing agents; and combinations thereof.

6. The composition of claim 1 , wherein the cationic curable component is selected from an epoxy component, an episulfide component, an oxetane component, a vinyl ether component and combinations thereof.

7. The composition of claim 1 , wherein the cationic curable component is an epoxy component selected from the group consisting of cycloaliphatic epoxy, aromatic epoxy, aliphatic epoxy and hydrogenated aromatic epoxy.

8. The composition of claim 7 , wherein the epoxy component comprises a member selected from the group consisting of epoxy-functionalized hydrogenated bisphenol-A, bisphenol-F, bisphenol-E, bisphenol-S and biphenyl.

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 first part further comprises phosphoric acid.

11. The composition of claim 1 , wherein the second part further comprises at least one of a plasticizer, a filler and a toughener.

12. The composition of claim 11 , wherein the toughener is a member selected from the group consisting of (1) (a) reaction products of the combination of ethylene, methyl acrylate and monomers having carboxylic acid cure sites, (2) (b) dipolymers of ethylene and methyl acrylate, (3) 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 the first part and the second part are present in a ratio of about 1:1 by volume.

14. The composition of claim 1 , wherein the first part and the second part are each housed in a separate chamber of a dual chambered container.

15. The composition of claim 1 , wherein the additive is a member selected from the group consisting of heterocycles, pyridines, benzothiazoles, toluidines, and phenolics.

16. The composition of claim 1 , wherein the additive is a member selected from the group consisting of 3,5-dibromopyridine, 3,5-dichloropyridine, N,N-dimethyl-p-toluidine, 2,2-dipyridyl disulphide, 5-chloro-2-methyl benzothiazole, 2-methyl-mercaptobenzothiazole, N,N-dihydroethyl-p-toluidine, t-butylbenzothiazole sulphonamide, 4-methyl-2,2-ditertiarybutylphenol and 4-methoxyphenol.

17. The composition of claim 1 , wherein the additive is present in an amount of about 0.1 to about 2% by weight.

18. The composition of claim 1 , wherein the second part comprises one or more of a cationic curable component, an additive to improve fixture time, a core shell rubber component and plastizer.

19. A method of improving fixture time in a two part cyanoacrylate/cationically curable adhesive system, steps of which comprises:

providing a two part cyanoacrylate/cationically curable adhesive system comprising (a) a first part comprising a cyanoacrylate component and a cationic catalyst; and (b) a second part comprising a cationic curable component; and

providing to the second part an additive to improve fixture Time, wherein when mixed together the cationic initiates cure of the cationic curable component.

20. A method of claim 19 wherein fixture time is improved at a spaced apart gap of 0 mm between aluminium substrates.