Ethylene-Vinyl Acetate (EVA)
Hot Melt Adhesives

Ethylene-vinyl acetate hot melt adhesives (EVA) are one of the most popular, most affordable and widely used industrial hot melt adhesives. They bond to a variety of cellulosic materials and are available in a wide range of compositions. They are of relative low-cost but also of relative low performance because, like most other hot melts, they have low creep resistance under load.

A typical EVA hot melt is formulated with 30 to 40% EVA copolymer, 30 to 40% tackifier resin and 20 to 30% aromatic or paraffinic hydrocarbon wax. The EVA copolymer provides strength, toughness and resistance, the tackifier resin improves wetting and tack, and the wax reduces viscosity and cost and enhances tack. Often stabilizers (antioxidants) are added to improve heat stability and resistance to UV light and, in some cases, fillers are added to lower cost and to modify the performance properties.

The vinyl acetate portion in the EVA copolymer promotes adhesion to polar substrates and increases flexibility and adhesion. It also lowers the crystallinity, which in turn improves optical clarity and provides improved low-temperature performance. The ethylene portion in EVA promotes adhesion to nonpolar substrates such as polyolefins, and increases mechanical strength, block resistance, and paraffin solubility. Some EVA hot melts can also be cross-linked, for example by peroxides, yielding a thermosetting hot melt with improved heat and creep resistance.

EVA formulations offer short to moderate open times up to one minute, and provide excellent adhesion to many substrates including paper, wood, plastics, rubbers, and metals. EVA’s can also be formulated as pressure-sensitive adhesives, which stay tacky after cooling and can be used for bonding tags and labels. Some adhesive manufacturers offer EVA hot melts that are FDA approved for direct or indirect food contact, allowing them to be used in food packaging and other food related applications. EVA hot melts are mainly used for general purpose bonding including cardboard box sealing and packaging. However, advances in raw materials and formulations now allow these adhesives to be used for automotive and other more demanding applications.

Common EVA hot melts provide satisfactory strength between -30 and 50°C (-20 and 120°F) and are generally limited to uses between -30 to 80°C (-20 and 175°F).