They are of relative low-cost but also of relative low […]
They are of relative low-cost but also of relative low performance. They bond to a variety of cellulosic materials and are available in a wide range of compositions.A typical EVA hot melt is formulated with 30 to 40% EVA copolymer which provides strength, toughness and resistance, 30 to 40% tackifier resin to improve wetting and tack, 20 and 30% aromatic or paraffin hydrocarbon wax to reduce viscosity and cost, and of stabilizer to improve heat stability at elevated temperatures and resistance to UV light.
In some cases, fillers are PE wrinkle free shirt tape added for special applications. The vinyl acetate portion in the EVA promotes adhesion to polar substrates such as paper and increases flexibility, adhesion, and provides better low-temperature performance. It also lowers the crystallinity and improves optical clarity, whereas the ethylene portion 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.Common EVA hot melts provide satisfactory strength between and are limited to use between and have, like most other hot melts, low creep resistance under load. EVA formulations offer short to moderate open times up to a 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 also 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.The majority of EVA hot melt applications are 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.