Adhesives suitable for use in bonding applications

1. An article comprising an adhesive layer, comprising:

i) at least one halogenated polyolefin having a weight average molecular weight of 200,000 to 400,000, wherein the halogen content ranges from 55 to 90 percent by weight, present in an amount in the range of 1 to 30 wt.-%, based on the weight of the adhesive;

ii) at least one epoxysilane having at least one terminal alkoxy silane group wherein the epoxysilane is present in an amount of 0.2 to 5 wt.-%, based on the weight of the adhesive;

iii) at least one bis-silane, wherein the bis-silane has two silicon atoms per molecule, wherein the two silicon atoms are linked with each other by a divalent linkage group and each silicon atom carries three additional substituents, wherein at least one of the three additional substituents is an alkyl or alkoxy residue, and the bis-silane is present in an amount of 0.1 to 2 wt.-%, based on the weight of the adhesive;

iv) optionally at least one organic solvent, wherein the weight ratio of epoxysilane to bis-silane in the adhesive is from 1:0.2 to 1:0.8 wherein the adhesive layer is, disposed between (a) a polar elastomeric substrate selected from the group consisting of nitrile butadiene rubber, hydrogenated nitrile butadiene rubber and ethylene acrylic elastomers, and (b) a metallic substrate.

2. The article of claim 1 , wherein the halogenated polyolefin is selected from chlorinated polyolefins.

3. The article of claim 1 , wherein the epoxysilane comprises a single epoxy group and a single terminal alkoxy silane group per molecule.

4. The article of claim 1 , wherein the epoxysilane is represented by formula (I)

wherein R a is a divalent linkage group, comprising 1 to 24 carbon atoms, R and R 3 independently of one another are selected from C 1-24 alkyl, C 2-24 alkenyl, C 1-24 alkoxyl or C 3-24 acyl, and R 2 is selected from C 1-24 alkyl or C 3-24 acyl, A is either

where R, R o and R d independently of one another are hydrogen or C 1-6 alkyl; or

5. The article of claim 1 , wherein the epoxysilane is represented by formula (II),

wherein n is an integer from 1 to 10, m is an integer from 0 to 14, R 1a and R 3a independently of one another are selected from C 1-24 alkyl, C 2-24 alkenyl, C 1-24 alkoxyl or C 3-24 acyl, and R 2a is selected from C 1-24 alkyl or C 3-24 acyl; or

is represented by formula (IIa),

wherein v is an integer from 1 to 10, R 1b and R 3b independently of one another are selected from C 1-24 alkyl, C 2-24 alkenyl, C 1-24 alkoxyl or C 3-24 acyl, and R 2b is selected from C 1-24 alkyl or C 3-24 acyl.

6. The article of claim 1 , wherein the epoxysilane is selected from 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropyltri-n-propoxysilane, 3-glycidyloxypropyltri-iso-propoxysilane, 3-glycidyloxypropyltri-n-butoxysilane, 3-glycidyloxypropyltri-iso-butoxysilane, beta-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, beta-(3,4-epoxycyclohexyl)-ethyltriethoxysilane, beta-(3,4-epoxycyclohexyl)-ethyltri-n-propoxysilane, beta-(3,4-epoxycyclohexyl)-ethyltri-iso-propoxysilane, gamma-(3,4-epoxycyclohexyl)-propyltrimethoxysilane, gamma-(3,4-epoxycyclohexyl)-propyltriethoxysilane, gamma-(3,4-epoxycyclohexyl)-propyltri-n-propoxysilane, gamma-(3,4-epoxycyclohexyl)-propyltri-iso-propoxysilane, and/or combinations thereof.

7. The article of claim 1 , wherein the bis-silane is represented by formula (III),

(R 5 O) (3-q) (R 4 ) q Si—B—Si(R 6 ) p (OR 7 ) (3-p)   formula (III)

wherein p is 0 to 3, q is 0 to 3, B represents a divalent linkage group comprising 1 to 24 carbon atoms and at least one heteroatom selected from N, S or O, each R 4 and each R 6 is independently selected from hydrogen, halogen, C 1-24 alkyl, C 2-24 alkenyl, C 1-24 alkoxyl or C 3-24 acyl, and each R 5 and each R 7 is independently selected from C 1-24 alkyl or C 3-24 acyl.

8. The article of claim 1 , wherein the bis-silane is represented by formula (IV),

(R 15 O) 3 Si—(R 14 ) k -D-(R 14 ) k —Si(OR 15 ) 3   formula (IV)

where k is 0 or 1, each R 15 is independently selected from C 1-4 alkyl or C 1-4 acyl, each R 14 is independently selected from C 1-6 alkylene or C 6-12 arylene, and D is selected from one of the following divalent groups:

where R 8a is selected from hydrogen, C 1-24 alkyl or C 6-18 aryl;

where each R 9a is independently selected from hydrogen, C 1-24 alkyl, or C 6-18 aryl, and R 10a is selected from C 1-24 alkylene or C 6-18 arylene;

where Y is selected from O, S or NR 11a , Z is selected from O, S, and NR 12a , wherein R 11a and R 12a independently of one another are selected from hydrogen, C 1-24 alkyl or C 6-18 aryl, and X is the selected from O or S, with the proviso that Y and Z are not both O or S.

9. The article of claim 1 , wherein the bis-silane is selected from bis-(trimethoxysilylethyl)amine, bis-(triethoxysilylethyl)amine, bis-(tri-n-propoxysilylethyl)amine, bis-(tri-iso-propoxysilylethyl)amine, bis-(trimethoxysilylpropyl)amine, bis-(triethoxysilylpropyl)amine, bis-(tri-n-propoxysilylpropyl)amine, bis-(tri-iso-propoxysilylpropyl)amine, bis-(trimethoxysilylethyl)urea, bis-(triethoxysilylethyl)urea, bis-(tri-n-propoxysilylethyl)urea, bis-(tri-iso-propoxysilylethyl)urea, bis-(trimethoxysilylpropyl)urea, bis-(triethoxysilylpropyl)urea, bis-(tri-n-propoxysilylpropyl)urea, bis-(tri-iso-propoxysilylpropyl) urea, and combinations thereof.

10. The article of claim 9 , wherein the adhesive is substantially free of nitroso-containing compounds.

11. The article of claim 1 , wherein the adhesive is a one-part adhesive.