Aging-resistant coatings and adhesive composites
View Patent ↗Curable compositions are provided which contain a curable component and particular m-hydroxybenzene derivatives, wherein such derivatives function as aging inhibitors. Such curable compositions are useful as coating agents and adhesives having improved aging resistance.
1. A curable composition comprising a curable component and at least one m-hydroxybenzene derivative of the general formula (I):
where Y is a carboxyl group, a carboxylate group or a straight-chain or branched alkyl group optionally substituted by hydroxyl groups, amino groups, carboxyl groups and/or carboxylate groups;
and R 1 , R 2 , and R 3 independently of one another are identical or different and are hydrogen or a hydroxyl group, and R 1 and R 3 are not simultaneously a hydroxyl group;
wherein the m-hydroxybenzene derivative of the general formula (I) is in interaction with iron(III);
with the provisos that, where the curable component is a thermosetting component of a multicomponent, epoxy-based system, the curable composition is free from transition metal oxides of the copper group and zinc group and that, where the curable component is an epoxy-based thermosetting component, the curable component is not a self-curing component.
2. The curable composition of claim 1 , wherein said curable composition is curable by radiation, heat, catalytically or a chemical curing agent.
3. The curable composition of claim 1 , wherein the curable composition is cured by a chemical curing agent which reacts with the curable component to cure the curable composition.
4. The curable composition of claim 1 , wherein the curable component is selected from the group consisting of epoxy compounds, (meth)acrylic acid and esters thereof, and polyols.
5. The curable composition of claim 1 , wherein the curable component is an amine-curing epoxy compound or a polyisocyanate-curing polyol.
6. The curable composition of claim 1 , wherein the curable component is a bisphenol A-epichlorohydrin adduct.
7. The curable composition of claim 1 , wherein a polyamine having at least two nitrogen atoms and at least two active amino hydrogen atoms per molecule is used as a curing agent.
8. The curable composition of claim 1 , wherein one or two of the radicals R 1 , R 2 or R 3 are hydroxyl groups.
9. The curable composition of claim 1 , wherein the compound of the general formula (I) is present in an amount of less than 10% by weight based on the total curable composition.
10. The curable composition of claim 1 , wherein the compound of the general formula (I) is present in an amount of 0.5% to 9% by weight, based on the total curable composition.
11. The curable composition of claim 1 , wherein the compound of the general formula (I) is present in an amount of 2% to 6% by weight, based on the total curable composition.
12. The curable composition of claim 1 , wherein the m-hydroxybenzene derivative of the general formula (I) is present in the form of an iron(III) complex.
13. The curable composition of claim 1 , wherein the curable composition is a coating composition or an adhesive.
14. The curable composition of claim 1 , wherein the curable composition is cold-curable.
15. The curable composition of claim 1 , wherein the curable composition is curable at temperatures below 100° C.
16. The curable composition of claim 1 , wherein the curable composition is curable at a temperature between 15° C. and 95° C.
17. The curable composition of claim 1 , wherein the curable composition is curable below 100° C. and comprises an epoxy compound as curable component and an amine having at least two amino groups as curing agent.
18. The curable composition of claim 1 , wherein Y is a carboxyl group.
19. The curable composition of claim 1 , wherein said m-hydroxybenzene derivative is selected from the group consisting of iron (III) complexes of 3-hydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid, 3-hydroxysalicylic acid, 3,5-dihydroxybenzoic acid, and mixtures thereof.
20. A process comprising coating a substrate with a curable composition, wherein the curable composition comprises a curable component and at least one m-hydroxybenzene derivative of the general formula (I):
where Y is a carboxyl group, a carboxylate group or a straight-chain or branched alkyl group optionally substituted by hydroxyl groups, amino groups, carboxyl groups and/or carboxylate groups;
and R 1 , R 2 , and R 3 independently of one another are identical or different and are hydrogen or a hydroxyl group, and R 1 and R 3 are not simultaneously a hydroxyl group;
wherein the m-hydroxybenzene derivative of the general formula (I) is in interaction With iron (III);
with the proviso that, where the curable component is a thermosetting component of a multicomponent, epoxy-based system, the curable composition is free from transition metal oxides of the copper group and zinc group and that, where the curable component is an epoxy-based thermosetting component, the curable component is not a self-curing component.
21. The process of claim 20 , wherein the curable composition comprises a curing agent or is heat- or radiation-curable and is cured.
22. The process of claim 20 , wherein the curable composition comprises a curing agent or is heat-curable and is contacted with a further substrate such that the curable composition coated on the substrate is situated between the substrate and the further substrate and is cured in a further step.
23. The process of claim 20 , wherein the substrate is a metallic substrate.
24. The process of claim 20 , wherein the substrate is a metallic substrate selected from the group consisting of aluminum, steel, copper, or alloys thereof.
25. The process of claim 20 , wherein the m-hydroxybenzene derivative of the general formula (I) is present in the form of an iron(III) complex.
26. An assembly comprising a first substrate, a second substrate, and a layer of the curable composition of claim 1 between said first substrate and said second substrate.
27. A coated substrate comprising a substrate and the curable composition of claim 1 coated thereon.