Ethylene-Vinyl Acetate (EVA) and Hot Melt Adhesives

Ethylene-Vinyl Acetate (EVA) and Hot Melt Adhesives Ethylene-vinyl acetate (EVA) is a copolymer of ethylene and vinyl acetate. The weight percentage of vinyl acetate typically ranges from 10% to 40%, with the remainder being ethylene.

Formulation and Composition Ethylene

Ethylene supports adhesion to non-polar substrates such as polyethylene and provides mechanical strength, block resistance and paraffin solubility. Vinyl acetate, on the other hand, supports adhesion to polar substrates such as paper and provides flexibility, tack and better low-temperature performance. How the adhesive is formulated will directly affect its properties. For example, a higher ethylene ratio in the formulation provides increased strength and resistance to the specific EVA adhesive, while a larger amount of vinyl acetate provides stronger adhesion to paper products and improves the flexibility of the adhesive. Formulations containing higher amounts of vinyl acetate can also work at lower temperatures, have better wettability (industry term) to substrates, and have longer open times and slower set times.

Properties of EVA

EVA adhesives vary in properties depending on their specific formulations, but in general, they adhere to the widest range of substrates, function in one of the widest temperature ranges for hot melt adhesives, and above all, are the most cost-effective. EVA hot melt adhesives typically require an application or melting temperature of 350°F (176°C) and have a wide viscosity range between 900-3,000 cPs. Most EVA adhesives have a relatively fast setting speed. However, it is important to remember that if a formulation with a higher vinyl-acetate ratio is used, the setting time will be somewhat longer. EVA adhesives can work at temperatures as low as -40°F (-40°C) and as high as 160°F (71°C), depending again on the formulation.

Ethylene-Vinyl Acetate Hot Melt Adhesives

Ethylene-vinyl acetate (EVA) and polyolefin or metallocene are among the main types of industrial hot melt adhesives. EVA is a copolymer adhesive most commonly used in the paper, packaging and assembly industries because it adheres to various cellulosic materials and has a wide range of formulations. The composition of the adhesive will directly affect its properties. Since EVAs can be specially formulated for various applications, various types exist on the market. Hot melt adhesives serve a wide range of industries for various applications, including paper and packaging, woodworking, graphic arts, assembly and automotive industries. Hot melt adhesives are currently the most popular and widely used type of industrial adhesive available in today's market. Hot melt adhesives are polymer-based and thermoplastic in nature, meaning they are solid at room temperature. These adhesives do not use water or solvents to obtain adhesive properties, which gives them a very fast hardening time, long shelf life and functionality over a wide temperature range.

Industries and Applications

Due to their versatility, reliability and durability, EVA hot melt adhesives are used in a wide range of industries for various applications. These industries include woodworking, assembly and automotive industries. Increasing demand for EVA is prominent in the packaging industry due to its superior vibration and impact absorption properties. EVA adhesives are specially formulated to adhere to paper, cardboard and waxed surfaces. Therefore, they are ideal for use in the packaging industry dealing with a wide variety of products and industrial applications. These products include paper/card stock boxes, package labeling, carton sealing, assembly and paper converting and many different applications.

Other Areas of Use

EVA is typically extruded together with polyethylene. A key property of EVA is that it lowers the softening and melting points of polyethylene films. It also increases the impact resistance and puncture resistance of the films. EVA serves as an encapsulant for solar cells or modules. Essentially, it can be used as a copolymer film that serves as a basic sealant for photovoltaic solar modules to provide reliability and performance. Ethylene-vinyl acetate (EVA) is considered an ideal material for the footwear industry with properties such as heat, structural design, high impact and use absorption, and stress-crack resistance. Ethylene-vinyl acetate (EVA) is also used in many different sectors such as packaging, biotechnology and photovoltaics. Due to all these advantages, it is expected that the global ethylene-vinyl acetate (EVA) market will expand further in the future. Sertaç Güler Technical Sales Manager Boyss Petrochemical