Colored vinyl ester gelcoat

Vinyl ester gelcoat is a synthetic resin obtained from the reaction of bifunctional organic acids and polyfunctional alcohols.

Maleic anhydride, with two acid functional groups, is a common raw material for producing polyester resin. Polyester resins are used in mold-making materials, as toner in laser printers, and as a binder in oven-baked polyester paints.

Vinyl ester gelcoat for wall panels made of fiberglass-reinforced polyester resin is typically used in restaurants, kitchens, and other places requiring washable walls.

Unsaturated polyester resins are condensation polymers formed from the reaction of polyols (polyhydric alcohols) with bifunctional carboxylic acids.

Common polyols include glycols such as ethylene glycol. The acids used are primarily phthalic acid and maleic acid.

During the reaction, water (a byproduct) is continuously removed to drive the reaction toward completion. The use of unsaturated polyesters and additives such as styrene reduces the resin’s viscosity.

The initial liquid resin solidifies through crosslinking. This is accomplished by generating free radicals at unsaturated bonds, propagating through a chain reaction with unsaturated bonds of adjacent molecules, and linking them together.

Initial free radicals are formed by adding a compound that readily converts to a free radical. This compound is often incorrectly called a catalyst; initiator is a more appropriate term. The materials used are typically organic peroxides such as benzoyl peroxide or methyl ethyl ketone peroxide.

Polyester resins are thermosetting and cure exothermically, like other resins. Excessive use of initiator, especially in the presence of a catalyst, can cause burning or even combustion during the curing process.

GELCOAT

Hand-apply gelcoat – for making parts and molds in various colors, can be applied like putty with a spatula.

Spray-apply gelcoat – for making parts and molds in various colors, sprayable.

Gelcoat is the first layer we see in a composite part. Therefore, it must have properties that provide sufficient resistance to environmental factors. In addition to environmental resistance, it must have good surface smoothness and color to achieve an attractive appearance. Hence, the materials used to make gelcoat must meet these requirements.

Aerosil resin

Capoxyl acid gelcoat

Cobalt talc

Filler (MEL)

Color paste

Color powder