Storage stable water based epoxy-amine curable systems
AssigneeHexion Inc.
InventorsJim Elmore, Pascale Claeys-Bouuaert, Françoise Heine
Life of this patent
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Abstract
The invention relates to non aqueous curing agents for water dispersed epoxy resins. The curing agent composition offers a binder pot life of several hours, and in the presence of a metal, such as zinc, nearly no hydrogen generation is observed. The present curing composition can be mixed with a metal powder to provide a storage stable paste. The curing agent composition and/or paste is fully compatible with an epoxy water based resin. After low shear blending, the epoxy curing agent and metal system is storage stable for several hours working pot life that provides for cured coatings having good performance.
Claims20
A curing agent for epoxy resins comprising:
- (a) a first amine adduct, which is a reaction product of an amine-terminated intermediate and a monofunctional epoxy compound, wherein the amine-terminated intermediate is prepared by reacting at least one polyamine or polyamidoamine, having at least 3 active amine hydrogen atoms per molecule, and at least one epoxy resin having a functionality of at least 1.5, in a mole ratio of 0.9:1 to 1:10 of an epoxy functionality equivalents to polyamine or polyamidoamine, wherein the excess of the polyamine or polyamidoamine being eliminated, and wherein the monofunctional epoxy compound is present in an amount calculated to react away the primary amines still present in the amine-terminated intermediate,
- (b) an optional second amine adduct which is prepared from a cycloaliphatic alkyl amine or polyamine and an epoxy compound,
- (c) a sterically hindered hydrophobic alkyl amine or diamine, a hydrophobic hydrocarbon resin, or both,
- (d) a component having amino or polyamino polyalkyleneglycol moieties a medium to low molecular weight amino silane, or both, and
- (e) an optional metal powder.
A paint or coating composition comprising the water based epoxy resin formulation of claim 7 and 15-80 wt % zinc metal powder, the wt% zinc metal powder based on the weight of the paint or coating composition, or 15-95 wt % zinc metal powder, the wt % zinc metal powder based on the weight of the dry applied and cured paint.
A method for preparing a curing agent comprising:
- (a) reacting at least one polyamine or polyamidoamine, having at least 3 active amine hydrogen atoms per molecule, and at least one epoxy resin having a functionality of at least 1.5, in a mole ratio of 0.9:1 to 1:10 of an epoxy functionality equivalents to polyamine or polyamidoamine to produce an amine-terminated intermediate, removing any excess of polyamine or polyamidoamine, then further reacting the amine-terminated intermediate with a monofunctional epoxy compound in an amount calculated to react away primary amines in the amine-terminated intermediate to prepare a first amine adduct,
- (b) optionally adding the first amine adduct obtained in step (a) with a second amine adduct obtained by partially reacting a cycloaliphatic alkyl amine or polyamine with an epoxy compound to obtain an amine adduct blend,
- (c) adding a sterically hindered hydrophobic alkyl amine or diamine, a hydrophobic hydrocarbon resin, or both, to the first amine adduct of step (a) or to the amine adduct blend of step (b) to obtain a second blend,
- (d) further adding a component having amino or polyamino polyalkyleneglycol moieties, a medium to low molecular weight amino silane, or both, to the second blend obtained in step (c) to form a third blend, and
- (e) optionally adding a metal powder to the third blend.
Dependencies are inferred from the claim text.