The composite materials have important advantages reported to the traditional materials like metal and wood. They bring a number of functional advantages: low weight, chemical and mechanical resilience, low maintenance costs, the liberty of shapes and dynamic design.
They allow prolonging the life of certain equipments because of chemical and mechanical properties. These materials contribute to the safetyness because of the better resistance to fire and shocks. Offers a good phonic and thermal isolation. In every area of marketing – automobiles, constructions, electricity, industrial equipments- these remarkable performances are at the origins of innovative theological solutions.
Polyester resin – the basic ingredient of the gelcoat is the polyester resin, which provides chemical composition, which establishes the physical and chemical properties of the gelcoat.
Orthophthalic resin – is the resin used in general purpose where the upper resins (anhydrides or acid) resistant to water and chemicals are not of major importance. For many years it was one of the raw materials incorporated in the polyester resin; it can still be found in this composition but it is often replaced by the more sustainable isophtalic resins.
Isophtalic resin –used for the manufacture of boats, bathtubs and showers.They have a higher resistance to water, corrosion and chemicals with a high degree of flexibility.
Although the gelcoat was not used in the early days of the GRP industry, the need of surfaces rich in resins to protect the structured laminates, has made the gelcoat a vital component, as the gelcoat:
- improves the durability of the components;
- protects the laminated materials from the surrounding environment;
- reduces the fiber marking;
- helps in getting a smooth and aesthetical aspect;
- eliminates the need for painting.
In order to reduce the gelcoat leakage, its coloring, and to improve the air removal, the manufacturers use additives and resin to ensure the application of a rich surface layer, with a sufficient thickness in order to provide the desired aspect.
The manufacture of a product in a hall, on a mold, resulted in a variation from batch to batch depending on composition and color. This fact led the resins manufacturers to introduce new gelcoat with the following advantages:
- the proper dispersion of the thixotripoc agents, surfactants, pigments and accelerators;
- excellent air release features;
- exact color matching;
- the need to add only one component in the workshop– catalyst.
The recent development of the gelcoat
In time the need for gloss and color fixing of the gelcoat, which led to the development of the resins with improved and UV resistant additives, led to the manufacture of gelcoats that have been tested in severe weather conditions, without losing their gloss or color- so that it can be perceived by the human eye.
As there are requests for gelcoats with increased durability, there is also a demand regarding the reduction of the styrene from the gelcoat. That results in a demand of gelcoat with low content of styrene. These gelcoats are effective against the formation of blisters.
The gelcoats makes the fiberglass reinforced products attractive and practical.