Epoxy resin systems are mixtures made up of varying amounts of several components. The main components of epoxy resin systems are the epoxy resin and the curing agent (also known as hardener). In addition, other components of the epoxy resin system may include solvents, reactive diluents and fillers. In general, epoxy resin systems have hazardous properties, but can be handled safely. The hazards associated with the specific epoxy resin system being handled will depend on the hazardous properties of the components. The following sections describe potential hazards associated with the various components of epoxy resin systems.
EPOXY RESINS
Epoxy resins are a family of synthetic resins including products that range from liquids to solids. The most common resins are produced by reacting epichlorohydrin with bisphenol A or bisphenol F. The three general classes of epoxy resins are liquid, solid and modified liquid.
General Classes
Liquid resins are mild to moderate irritants to the skin, eyes and mucous membranes. The irritant potential is increased by their "sticky" nature, which tends to lead to prolonged skin contact. These resins are generally mild to moderate dermal (skin) sensitizers in susceptible individuals.
Solid resins are not readily absorbed through the skin and present a low risk of skin irritation. Direct contact with solutions of these resins can cause mild to moderate irritation of the skin and the eyes, principally because the solvents "de-fat" the skin. When crushed to a fine powder, the materials should be considered an irritant dust; inhalation and skin contact should be avoided. Solid resins are generally low to mild sensitizers.
Modified liquid resins are resins modified by the addition of reactive diluents (see page 3) or solvents (see page 2). Both chemicals and water are used as solvents. When water is used, the resins are referred to as "waterborne resins." These resins should be handled with the same precautions as those in chemical solvents. They are mild to moderate skin irritants. These low molecular weight resins and the reactive diluents are moderate to strong sensitizers. Their sensitizing potential tends to increase with decreasing molecular weight. Epoxy components with significant volatility could cause irritation to skin, eyes and respiratory tract, but inhalation is normally not a hazard except under certain conditions of use, i.e., heating, spraying, or applications with large surface areas. Certain modified resins, such as cycloaliphatic epoxy resins have been shown to cause skin cancer in laboratory animals.
