Corrosion-Preventive Adhesive Compositions
The present invention concerns adhesive compositions that provide corrosion-preventative properties and improved adhesive bonding on corrodible surfaces, such as may be found in electronic components. These compositions provide the substrates with greatly increased resistance to corrosion, especially during long term exposure to high temperatures and/or high humidity. When used on conductive substrates, the compositions also maintain good initial and ongoing electrical conductivity.
1 . A corrosion-preventive adhesive composition comprising (a) a radical curing resin, (b) a filler, and (c) an azo compound.
2 . The corrosion-preventive adhesive composition according to claim 1 in which the azo compound is an azo initiator.
3 . The corrosion-preventive adhesive composition according to claim 2 in which the azo compound is selected from the group consisting of 2,2′-azobis(2,4-dimethylvaleronitrile); 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile); 2,2′-azobis(2-amidinopropane)dihydrochloride; 2,2′-azobis(isobutyronitrile); 2,2′-azobis-2-methylbutyronitrile; 1,1-azobis(1-cyclohexanecarbonitrile); 2,2′-azobis(2-cyclopropylpropionitrile); and 2,2′-azobis(methyl isobutyrate).
4 . The corrosion-preventive adhesive composition according to claim 3 in which the azo compound is 2,2′-azobis(2,4-dimethylvaleronitrile).
5 . The corrosion-preventive adhesive composition of claim 1 , wherein the filler is a conductive filler.
6 . The corrosion-preventive adhesive composition of claim 5 , wherein the conductive filler is a transparent conductive filler.
7 . The corrosion-preventive adhesive composition of claim 6 , wherein the transparent conductive filler is indium tin oxide solder.
8 . The corrosion-preventive adhesive composition of claim 5 , wherein the conductive filler is selected from the group consisting of silver, copper, nickel, gold, tin, zinc, platinum, palladium, iron, tungsten, molybdenum, carbon black, carbon fiber, aluminum, bismuth, tin, bismuth-tin alloy, carbon nano tube, silver coated glass, graphite, conducting polymer, metal coated polymer and mixtures thereof.
9 . The corrosion-preventive adhesive composition of claim 1 , further comprising a free-radical initiator.
10 . The corrosion-preventive adhesive composition of claim 9 , wherein the free-radical initiator is a peroxide initiator.
11 . The corrosion-preventive adhesive composition according to claim 1 comprising from about 5 to about 95 weight percent radical curing resin; from about 2 to about 95 weight percent filler; and from about 0.1 to about 10 weight percent azo compound.
12 . The corrosion-preventive adhesive composition according to claim 11 comprising from about 10 to about 60 weight percent radical curing resin; from about 5 to about 85 weight percent filler; and from about 0.2 to about 5 weight percent azo compound.
13 . The corrosion-preventive adhesive composition according to claim 1 in which the radical curing resin is selected from the group consisting of acrylate resins, methacrylate resins, maleimide resins, bismaleimide resins, vinylester resins, poly(butadiene)resins, and polyester resins.
14 . The corrosion-preventive adhesive composition according to claim 13 in which the radical curing resin is an acrylate resin.
15 . A method of coating a metal substrate to prevent corrosion, wherein such method comprises the steps of a) providing a corrosion-preventive adhesive composition according to claim 1 ; and b) applying the corrosion-preventive adhesive composition to the metal substrate.
16 . A method of coating a metal substrate according to claim 15 , wherein such method comprise the additional step of curing the corrosion-preventive adhesive composition.
17 . A consumer product comprising the corrosion-preventive adhesive composition of claim 1 .