What is EVA hot melt adhesive?
What is EVA hot melt adhesive?
EVA hot melt adhesive is a solid meltable polymer that does not require solvents and does not contain 100% moisture; it is solid at room temperature, and when heated and melted to a certain temperature, it becomes a fluid and viscous liquid. The melted EVA hot melt adhesive is light brown or white. EVA hot melt adhesives are composed of basic resins, tackifiers, viscosity modifiers and antioxidants.
Basic resin introduction of EVA hot melt adhesive:
The basic resin of hot melt adhesive is the copolymerization of ethylene and vinyl acetate under high temperature and pressure, that is, EVA resin. This kind of resin is the main component of making hot melt adhesive. The proportion and quality of the basic resin determine the basic performance of hot melt adhesive, (such as adhesive bonding ability, melting temperature and bonding strength). Generally, the VA content is 18-33. Melting fat (MI) 6-800, low VA content, the higher the crystallinity, the greater the hardness. Under the same circumstances, the larger the VA content, the lower the crystallinity and the higher the elasticity. The choice of EVA melting fat is also very important. The smaller the melting fat, the poorer the fluidity High strength, high melting temperature, poor wetting and permeability to the adherend. On the contrary, if the melting fat is too large, the melting temperature of the glue is low, the fluidity is better but the bonding strength is reduced.
Tackifier
Tackifier is one of the main additives of EVA hot melt adhesive. If only the basic resin has the cohesive force at a certain temperature when it is melted, when the temperature drops, it will be difficult to wet and infiltrate 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 of hot melt adhesives. Its function is to increase the fluidity of the colloid and adjust the solidification speed to achieve the purpose of fast bonding and firmness. Otherwise, the viscosity of the hot melt adhesive is too high, unable or difficult to flow, and it is difficult to penetrate into the signature, so it cannot be bonded firm. Adding a viscosity regulator with a low softening point can achieve the purpose of good penetration and firm adhesion during bonding.
Antioxidant
Adding an appropriate amount of antioxidant is to prevent premature aging of EVA hot melt adhesive. Because the colloid will be oxidized and decomposed when the temperature is too high when it is melted, adding an antioxidant can ensure that the bonding performance does not change under high temperature conditions.
In addition to the above raw materials, some anti-cold agents suitable for cold temperatures or heat-resistant agents suitable for tropical temperatures can also be added according to the differences in temperature and region.
Application of EVA hot melt adhesive
Hot melt adhesives are the most widely used adhesives in textiles, especially in garment processing, and are widely used in the bonding of non-woven fabrics, carpet seams, clothing linings, zippers, etc. Hot melt adhesives used in the textile industry must have good bonding strength, excellent softness, and water/dry cleaning resistance. In addition, because most of the fabrics are steam-treated during the setting process, the glue is required to have the characteristics of high-temperature steam resistance, and its softening point is required to be higher than 115°C. It must have appropriate crystallinity to improve the thermal stability of the glue. For example, with polyamide as the matrix, the lower limit content is 45% (mass fraction). For fiber fabrics with excellent softness, the hot melt adhesive is required to have a lower processing viscosity.
EVA tape suppliers
MASBOND EVA tape MB-634 is made of polyethylene film and resin glue, which has the advantages of low processing temperature, antibacterial and strong adhesion. Different thicknesses have different percentages of ingredients.
MASBOND EVA Tape MB-634 is suitable for all kinds of EVA coated fabrics, non-woven fabrics and rubber coated fabrics. For example, chemical protective clothing, dustproof clothing, antibacterial clothing, safety clothing, medical protective clothing, etc.
If you want to know more about EVA hot melt adhesive or EVA tape, please feel free to contact us.