Do you know the main components of hot melt adhesives?

Do you know the main components of hot melt adhesives?

EVA hot melt adhesive
EVA hot-melt adhesive is a solvent-free, 100% solid fusible polymer; it is a solid at room temperature, heated 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 mainly composed of basic resin, tackifier, viscosity regulator and antioxidant.

Basic resin
The basic resin of hot-melt adhesive is ethylene and vinyl acetate copolymerized under high temperature and high pressure, namely EVA resin. EVA resin is the main component for making hot-melt adhesives. The proportion and quality of basic resin determine the basic performance of hot-melt adhesives (such as the adhesive capacity, melting temperature and adhesive strength of adhesives). Generally, the VA content is 18-33. Refers to (MI) 6-800, with low VA content, the higher the crystallinity, the higher the hardness. Under the same circumstances, the larger the VA content, the lower the crystallinity, the higher the elasticity. The selection of EVA melt fingers is also important. A large melting temperature and high wettability and poor permeability of the adherend. On the contrary, if the melting point is too large, the melting temperature of the glue is low, the fluidity is good, but the bonding strength is reduced. The choice of additives should choose the proper ratio of ethylene and vinyl acetate.
Tackifier
Tackifier is one of the main additives of EVA hot melt adhesive. When the basic resin is melted, it has a bonding force at a certain temperature. 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. General tackifiers include rosin, modified rosin (138 or 145), C5 petroleum resin, C9 petroleum resin, terpene resin, etc.
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 to achieve the purpose of fast bonding and firmness. Adding a viscosity modifier with a low softening point can achieve the purpose of good penetration and firm adhesion during bonding. Generally choose paraffin wax, microcrystalline wax. Synthetic wax (PE or PP), fossil wax, etc.
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.

Foshan JCT Machinery Co., Ltd. is a research, development, design, manufacture, installation, commissioning and maintenance in one of the chemical machinery professional equipment manufacturers. The company has successfully developed a resin, adhesive type, powder mixed type, silicone type, hot melt type, paint type and other complete sets of production equipment, products across the chemicals, plastics, building materials, pharmaceuticals, food, light industry and other industry.