Curable epoxy composition with quaternary ammonium bicarbonate curing catalyst
AssigneeE. I. Du Pont de Nemours and Company
InventorPui-Yan Lin
Life of this patent
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Abstract
Quaternary ammonium bicarbonates are suitable for use as catalysts in curable epoxy compositions. The curable compositions prepared therewith are used to prepare coated substrates, and to produce conformally sealed printed wiring boards and flexible circuits. Methods for preparation and curing are also provided. Of particular utility are compositions comprising benzytrimethyl ammonium bicarbonate.
Claims15
A curable composition comprising an epoxy having a plurality of cross-linkable epoxide functional groups, a curing agent, and quaternary ammonium bicarbonate represented by Structure I.
- R1R2R3R4N+HCO3− I
- wherein each of R1, R2, R3, and R4 are independently alkyl, phenyl, alkylbenzene, H, alkoxy, with the proviso that at least one of R1, R2, R3, and R4 is not H.
The curable composition of claim wherein the epoxy comprises bisphenol A or bisphenol F, the curing agent is phenolic, and the quaternary ammonium bicarbonate is benzyltrimethyl ammonium bicarbonate,
A method for curing an epoxy composition, the method comprising combining an epoxy having a plurality of cross-linkable epoxide functional groups, a phenolic curing agent, a quaternary ammonium bicarbonate in a solvent to form a reaction mixture, removing said solvent, heating said reaction mixture to a temperature in the range of 120 to 200° C., and maintaining the temperature until the desired level of curing has taken place, wherein the quaternary ammonium bicarbonate is represented by Structure I.
Dependencies are inferred from the claim text.