Copromoters for Gel Coats

Preparing Resins for Gel Coats 

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A gel coat is a hard, smooth-surface finish applied to fiberglass composites. Gel coats are often applied to the surface of boat hulls, and are expected to be durable for long-lasting protection and have good color definition. Gel coats are made from polyester resins, and the production of the resin is key to making a high-quality gel coat. Many intermediates are needed to prepare these resins, including glycols, such as NPG and TMPD, diacids and diesters, inhibitors, additives, and copromoters. Copromoters are important in assisting with a complete and rapid cure, and providing additional benefits to the finished resin. DMAA and AAEMA are widely used as copromoters in polyester resins for gel coat applications. 

Arxada Focus Products

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Arxada Diketene Derivatives offer unique advantages as copromoters in gel coats, namely DMAA and AAEMA. DMAA is the most widely used copromoter in gel coats because of its low toxicity, ease of handling, and low color. In addition to its low color and easy handling, AAEMA provides added benefits over DMAA. AAEMA has an active double bond in its methacrylate group, allowing free radical polymerization. This makes AAEMA a reactive copromoter that can polymerize into the polymer backbone. Also, AAEMA is a low-viscosity liquid, and can replace some styrene to create a high-solids coating. Finally, AAMEA demonstrates less in-box yellowing and better storage stability in some resin systems.