Epoxy resins and are characterised by their excellent durability, strength, chemical resistance and low absorption of moisture. Commonly used for laminating, epoxy resin can be used as a protective coating as well as materials in circuit boards and for patching holes in concrete pavements. These versatile resins offer high strength resistance to corrosion. Epoxy resins offer a high strength to weight ratio and dimensional stability as well as adhesion properties make them ideal for a wide range of applications. Different resins are produced by varying the ratios of the chemical components.
Epoxy resins are typically low odour compared to vinylester resins or polyester resins and usually involve mixing two components, resin and hardener, with a mixing ratio of relatively equal proportions. Resins are usually high in viscosity (a measure of its resistance to flow) so that they are moulded at temperatures around 50 to 100°C, or dissolved in an inert solvent (a solvent that does not react with anything in solution, epoxy cannot be thinned down with thinners) to reduce viscosity to a point at which lamination at room temperature becomes possible. Low viscosity epoxies are typically used in RTM (resin transfer moulding) for the casting of parts.
Most epoxy resins are an industrial product derived from petroleum and are themselves the result of a chemical reaction called curing. This involves epoxies and other chemicals more commonly known as hardeners or curing agents. Depending on the type of reaction used to produce the resin, they can be either low-molecular honey-like liquids or high-molecular, solid substances. Their molecular weight often determines their potential uses and applications.