Evonik Operations Gmbh

Douglas M La Comare

Gauri Sankar Lal

Pritesh G Patel

Gauri Sankar Lai

A curing agent composition comprising anhydride and approximately equimolar amount of tertiary amine or imidazole and carboxylic acid, the amine being 1-piperidinylethanol (N-hydroxyethyl-piperidine, NHEP) represented by the structure below or an imidazole represented by the structure below: where R=H, a C1-C20 straight chain or branched alkyl, or a monocyclic aryl; R=a C1-C20 straight chain or branched alkyl, or a monocyclic aryl. The carboxylic acid is represented by RCOOH; R=a C1-C20 straight chain or branched alkyl, or a monocyclic aryl. The composition comprises a lower ratio of epoxy resin to anhydride (1:0.4-0.6) than typically used (1:0.8-1.1). In addition, it uses a higher loading of the hindered latent tertiary amine or the imidazole in combination with the carboxylic acid (wt % ratio of combined amine and carboxylic acid to anhydride &#x2dc;10%). With this composition a full cure can be achieved in less than 2 hr at a significantly lower temperature (&#x2dc;100&#xb0; C.).

Low temperature anhydride epoxy cured systems

The present invention relates to an amine-based curing agent comprising at least 1% by weight of at least one tertiary amine and, optionally, primary and/or secondary amines. The tertiary amine is preferably an N-substituted piperidine tertiary amine and, more preferably, N-hydroxyethyl piperidine (NHEP). The present invention also relates to an epoxy resin composition formed using this amine-based curing agent and a method of making the epoxy resin composition. These tertiary amines enhance desirable properties of epoxy resin compositions without the negative impact on mechanical properties in the cured product normally seen with tertiary amine-based curing agents.

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Northampton, PA, United States of America

Douglas M La Comare