Which is better, PUR hot melt adhesive or EVA hot melt adhesive?

1. PUR (Polyurethane Reactive), the full name is moisture-curing reactive polyurethane hot melt adhesive, the main component is isocyanate-terminated polyurethane prepolymer, one-component, 100% solid content. the

2. Features: PUR hot melt adhesive, adjustable adhesion and toughness (elasticity), excellent bonding strength, good high and low temperature resistance, water resistance, abrasion resistance, zero chemical corrosion resistance and resistance Aging resistance, suitable for bonding of plastics and metals, widely used in electronics, automobiles, textiles, electromechanical, aerospace and other national economic fields. the

3. Polyurethane hot-melt adhesive type: PUR hot-melt adhesive (one-component moisture-curing polyurethane adhesive), which is one of the types of polyurethane hot-melt adhesive. According to the chemical properties, there are two types of polyurethane hot melt adhesives: one is thermoplastic polyurethane hot melt adhesive, and the other is reactive polyurethane hot melt adhesive. the

Thermoplastic polyurethane hot melt adhesive, also known as hot melt polyurethane hot melt adhesive, is liquefied by heating and solidified by cooling. Reactive polyurethane hot melt adhesives are divided into two types: moisture curing type and closed type. After being liquefied by heating, they are crosslinked and solidified by cooling and moisture reaction. The PUR hot melt adhesive introduced today refers to moisture curing polyurethane hot melt adhesive.

2. Reaction mechanism

One-component moisture-curing polyurethane adhesive is made of terminal-NCO-based prepolymer as the base material, with thermoplastic resins, tackifying resins, antioxidants, catalysts, fillers and other additives that do not react with isocyanate groups. PUR glue is heated and melted into a fluid, coated on the surface of the substrate to be adhered, the two adherends are pasted together, and the bond is formed after cooling. The active hydrogen compound reacts with an NCO group to extend the chain to form a polymer with a cross-linked structure and high cohesion, which further enhances the adhesion. The -NCO group in the isocyanate is very easy to react with the compound containing active hydrogen .

3. The difference between PUR hot melt adhesive and EVA hot melt adhesive:

1. The composition is different. PUR hot melt adhesive belongs to polyurethane, and EVA adopts ethylene-vinyl acetate;

2. The reaction mechanism is different. PUR hot melt adhesive is cured by moisture and is irreversible after the reaction; EVA belongs to physical bonding, solidifies after cooling, can be re-melted after heating, and the operation is reversible. the

3. PUR hot melt adhesive is irreversible after curing, has higher strength and high and low temperature resistance, heat resistance, cold resistance, water vapor resistance, chemical resistance and solvent resistance. The rigidity of EVA hot melt adhesive is relatively poor, and the softening point is lower than that of PUR polyester, most of which are around 100°C, which limits its application range.

As for whether these contents are helpful to you or your company, we have a lot of purking products for pur hot-melt adhesive, eva hot-melt adhesive, hot-melt adhesive and other production processes. Welcome to consult, and we will also customize your favorite for you. The most suitable and cheaper hot melt adhesive