Views: 9 Author: Site Editor Publish Time: 2020-03-30 Origin: Site
What are the differences between PUR glue and EVA glue?
In the glue binding industry, there are two options of glue are mainly used, one we called EVA (Ethylene Vinyl Acetate) and another is PUR (Polyurethane Reactive) Most of us are confused with the two types of material, what’s the difference between them and which one should I choose for my job?
PUR is polyurethane, EVA is ethylene vinyl acetate
• Reaction mechanism
The reaction mechanism of PUR is moisture curing, which is an irreversible reaction. After heating, it will react with the moisture in the air after bonding. It will be irreversible after the reaction (even heating again). This irreversible reaction can provide better strength and high and low temperature resistance.
EVA is a physical bond. The glue is applied to the material to cool and solidify. After heating, it will be remelted, changed into glue and then adhered to the material, which is reversible.
• Packaging and use
The packaging of PUR hot-melt adhesive is sealed. Gluing requires professional equipment that can be sealed. EVA is not needed.
Advantages of PUR
1. Excellent flexibility and books could lay very flat when opened(Picture1)
2. Stronger glue performance that could easily handle coated/varnished paper, heavy ink coverage to the edges and some other difficult to bind materials.
3. Extreme temperature resistance, PUR bond books won’t get re-melting or cracking in the high/low temperature condition.
4. PUR bond strength can be as much as 40-60% greater than EVA once the adhesive has fully set.
Advantages of EVA
1. Cheaper price than PUR
2. Shorter curing time than PUR (EVA takes a few seconds, PUR needs 12-24hours. This means EVA bond books could turn to three knives trimmer shortly)
3. Easy maintaining and cleaning than PUR
Both of them are widely used for the different jobs, if most of your job are UV coated paper or album board etc, and the environmental condition is in a extreme temperature, then PUR is a better choice. On the contrary, if most of your job is binding the normal books or notebooks, then EVA is enough.