Universal primer compositions and methods
View Patent ↗A composition for and method for bonding a substrate. In general, applied to a substrate will be a primer composition that includes an adhesion promoter, which is an adduct prepared by the reaction of at least one aromatic polyisocyanate compound, with an active hydrogen containing moiety of an organofunctional silane, and a prepolymer derived from the reaction of at least one aliphatic polyisocyanate and a polyol, and is at least partially reacted with an active hydrogen containing moiety of an organofunctional silane.
1. A composition comprising a product of a reaction of i) an additive that includes the reaction product of a) a first reaction product of at least one isocyanate including a thiophosphate and a silane selected from an amino-least one isocyanate including a thiophosphate and a silane selected from an amino-silane, a mercapto-silane, or a combination thereof; and b) a second reaction product that is an isocyanate functional prepolymer with an isocyanate content greater than about 1%, which is a reaction product of a polyol having a functionality of greater than about 2 and a molecular weight (M n ) greater than about 300 and an aromatic isocyanate wherein the polyol consists essentially of polyether polyols, polyester polyols, poly(alkylene carbonate)polyols, hydroxyl-containing polythioethers, polymer polyols, and mixtures thereof; and ii) with at least one base primer composition that includes a prepolymer derived from the reaction of at least one aliphatic polyisocyanate and a polyol, and is at least partially reacted with an amino group of an aminosilane, wherein the aminosilane includes a plurality of alkoxy groups bound to silicon.
2. The composition of claim 1 , wherein the primer composition further includes i) diethylmalonate that is present in an amount up to about 2% by weight of the primer composition, ii) a phosphoric acid that is present in an amount less than about 0.2% by weight of the primer composition, or both i) and ii); a film former, a colorant, or a combination thereof, and further wherein in the primer composition, i) the base primer is present in an amount of about 50 to about 65% by weight; ii) the adhesion promoter is present in an amount of about 2 to about 7% by weight; iii) the isocyanate functional prepolymer with an isocyanate content greater than about 1% will be present in an amount of about 30 to about 40% by weight; iv) diethylmalonate is present in an amount of about 0.1 to about 0.5% by weight; v) acid is present in an amount of about 0.01 to about 0.05% by weight; or vi) any combination of i) through vi).
3. The composition according to claim 1 wherein i) the at least one aromatic polyisocyanate compound is trifunctional, ii) the at least one aromatic polyisocyanate compound includes tris(isocyanatophenyl)thiophosphate, or both i) and ii); and about 1 mole of the polyisocyanate is reacted with about 2.3 to about 3 moles amino-silane, mercapto-silane, or a combination thereof to prepare the adhesion promoter.
4. The composition according to claim 3 wherein the weight ratio of adhesion promoter to isocyanate functional prepolymer with an isocyanate content of greater than about 1 percent is about 1:140 to 1:1.
5. A kit comprising a primer composition and at least one adhesive wherein the primer composition comprises
i. an adhesion promoter, which is an adduct prepared by the reaction of at least one aromatic polyisocyanate compound, with an active hydrogen containing moiety of an organofunctional silane,
ii. a prepolymer derived from the reaction of at least one aliphatic polyisocyanate and a polyol, and is at least partially reacted with an active hydrogen containing moiety of an organofunctional silane;
iii. optionally, a solvent; and
iv. an isocyanate functional prepolymer with an isocyanate content greater than about 1%, and being the reaction product of a polyol and an aromatic polyisocyanate wherein the polyol has a functionality of greater than about 2 and a molecular weight (M n ) greater than about 300 and consists essentially of polyether polyols, polyester polyols, poly(alkylene carbonate)polyols, hydroxyl-containing polythioethers, polymer polyols, and mixtures thereof.
6. The kit according to claim 5 wherein the at least one aromatic polyisocyanate compound includes a thiophosphate, a phosphate, a thiophosphane moiety or any combination thereof.
7. The kit according to claim 6 wherein i) the at least one aromatic polyisocyanate compound is trifunctional, ii) the at least one aromatic polyisocyanate compound includes tris(isocyanatophenyl)thiophosphate, or both i) and ii).
8. The kit according to claim 7 wherein the organofunctional silane of the adhesion promoter is a mercapto silane, an amino silane, or a combination thereof, and wherein about 1 mole of the polyisocyanate is reacted with about 1 to about 3 moles amino-silane, mercapto-silane, or a combination thereof, provided that the molar ratio of hydrogen active groups to isocyanate groups is less than 1.0.
9. The kit according to claim 8 wherein the primer composition further includes a phosphoric acid, a film forming resin, or both.
10. The kit according to claim 9 wherein the adduct is present in an amount of about 0.5 to about 20% by weight; the prepolymer derived from the reaction of at least one aliphatic polyisocyanate and a polyol is present in an amount of about 10 to about 50% by weight; the aromatic polyisocyanate functional prepolymer with an isocyanate content greater than about 1% is present in an amount of about 20 to about 70% by weight; the solvent is present in an amount of about 40 to about 80% by wt.; diethylmalonate is present in an amount of about 0.1 to about 0.5% by weight; acid is present in an amount of about 0.01 to about 0.05% by weight.
11. The kit according to claim 10 wherein the primer composition includes at least one film former, a pigment or a catalyst, or a combination thereof.
12. The kit according to claim 8 wherein about 1 mole of the polyisocyanate is reacted with about 2.3 to about 3 moles amino-silane, mercapto-silane, or a combination thereof to prepare the adhesion promoter.
13. The kit according to claim 12 wherein the weight ratio of adhesion promoter to isocyanate functional prepolymer with an isocyanate content of greater than about 1 percent is about 1:140 to 1:1.
14. An additive for a primer composition comprising i) an adhesion promoter comprising a first reaction product of 1 mole of at least one isocyanate including a trifunctional, tris(p-isocyanato-phenyl)-thiophosphate and with about 2.3 to about 3.0 moles of a silane selected from an amino-silane, a mercapto-silane, or a combination thereof; and ii) a second reaction product that is an isocyanate functional prepolymer with an isocyanate content greater than about 1% generally formed by the reaction of a polyol having a functionality of greater than about 2 and a molecular weight (M n ) greater than about 300 and an aromatic isocyanate wherein the polyol consists essentially of polyether polyols, polyester polyols, poly(alkylene carbonate)polyols, hydroxyl-containing polythioethers, polymer polyols, and mixtures thereof; wherein the weight ratio of adhesion promoter to isocyanate functional prepolymer with an isocyanate content of greater than about 1 percent is about 1:140 to 1:1.
15. The additive of claim 14 , wherein the silane of the first reaction product is an amino-silane that includes at least two silyl groups, a methoxy silane ester, a hindered secondary amino group or any combination thereof.
16. A method of improving the performance of a primer composition, comprising the step of mixing an additive in an amount of about 1 to about 20 parts by weight to about 99 to about 80 parts by weight of the primer composition, wherein the additive includes the reaction product of i) a first reaction product of at least one isocyanate including a thiophosphate and a silane selected from an amino-silane, a mercapto-silane, or a combination thereof; and ii) a second reaction product that is an isocyanate functional prepolymer with an isocyanate content greater than about 1% generally formed by the reaction of a polyol having a functionality of greater than about 2 and a molecular weight (M n ) greater than about 300, and an aromatic isocyanate, wherein the polyol consists essentially of polyether polyols, polyester polyols, poly(alkylene carbonate)polyols, hydroxyl-containing polythioethers, polymer polyols, and mixtures thereof; with a base primer composition to form a resulting primer composition; and contacting a substrate selected from glass, metal, plastic, a coated substrate, or any combination thereof, with the resulting primer composition.
17. The method of claim 16 , wherein the primer includes at least one prepolymer derived from the reaction of at least one aliphatic polyisocyanate and a polyol, and is at least partially reacted with an amino group of an aminosilane, wherein the aminosilane includes a plurality of alkoxy groups bound to silicon.