Dry Goods Collection: Composition and Characteristics of EVA Hot Melt Adhesives for Binding

EVA hot-melt adhesive is a solid meltable polymer that does not require solvents and does not contain 100% moisture; it is a solid at room temperature, which is melted by heating to a certain temperature and becomes a fluid with a certain viscosity. The melted EVA hot melt adhesive is light brown or white. EVA hot melt adhesive is composed of basic resin, tackifier, viscosity regulator and antioxidant.

Basic resin

The basic resin of EVA hot melt adhesive is the copolymerization of ethylene and vinyl acetate under high temperature and high pressure, namely EVA resin. This resin is the main component for making hot melt adhesives, accounting for more than 50% of its ingredients. The proportion and quality of the basic resin determine the basic properties of the hot sol, such as the adhesive capacity of the glue, the melting temperature and the choice of additives. Therefore, the EVA hot-melt adhesive used for binding paper should be selected with an appropriate ratio of ethylene and vinyl acetate, with certain flexibility, elasticity, adhesion, and small deformation.

Tackifier

Tackifier is one of the main additives of EVA hot melt adhesive. The resin has a cohesive force at a certain temperature when it melts. When the temperature drops, it is difficult to wet and penetrate the paper, lose the cohesive ability, and cannot achieve the cohesive effect; adding a tackifier can improve the fluidity of the colloid And the wettability of the adherend, improve the bonding performance and achieve the required bonding strength.

Viscosity modifier

Viscosity modifier is also one of the main additives for hot melt adhesives. Its role is to increase the fluidity of the colloid and adjust the solidification speed in order to achieve the purpose of fast bonding and firmness, otherwise the hot melt adhesive viscosity is too large, unable or difficult to flow, difficult to penetrate into the signature, it can not be bonded Firm. Adding a viscosity modifier with a low softening point can achieve the purpose of good penetration and firm adhesion during bonding.

Antioxidant

The appropriate amount of antioxidant is added to prevent premature aging of EVA hot melt adhesive. Because the colloid will oxidize and decompose when the temperature is high, the addition of antioxidants can ensure that the bonding performance does not change under high temperature conditions.

In addition to the above raw materials, according to the temperature and regional differences, it can be equipped with some cold resistance agents suitable for cold temperatures or heat resistance agents suitable for tropical temperatures.