Hot Melt Adhesives

Posted by Ella Wang on July 26th, 2019

In high melt wax for hot melt adhesives, wax is the most effective regulator of adhesive properties. The main function of the wax is to reduce the melting point and viscosity of the hot melt adhesive, improve the fluidity and wettability of the glue, improve the bonding strength, prevent the hot melt adhesive agglomeration, and reduce the cost. In the polyurethane and polyamide hot melt adhesives, there is no addition of wax. The other hot melt adhesives are composed of certain wax. However, if the amount is too much, the shrinkage of the adhesive becomes large, and the bonding strength is rather lowered. Therefore, in order to achieve a large bonding strength, the amount of the wax should be controlled.

Commonly used waxes are paraffin waxes, microcrystalline waxes, PE wax and Fischer-tropsch wax. 

Alkane paraffin wax

the melting point 50-70 ° C, molecular weight 280-560. In corrugated board manufacturing, corrugated box molding, paper bag manufacturing and book binding,  paraffin wax are well applied in the EVA based hot melt adhesives and adjust the setting time,

Microcrystalline paraffin

the melting point 65-105 ° C, molecular weight 450-700, higher price, improve the flexibility, bonding strength, thermal stability and cold resistance of hot melt adhesives than alkane paraffin, but the anti-caking ability is lower than Alkane paraffin;

PE wax

has the good compatibility with ethylene/vinyl acetate copolymers and other hot melt adhesives. It has high melting points and high hardness, can Reduce the viscosity of the adhesive composition

Fischer-Tropsch wax

has the linear molecular structure with high melting point and low penetration. It has narrow melting range and good weather resistance. Therefore, it is widely used in applications requiring good weather resistance, high temperature and quick solidification.