PUR Adhesive VS EVA Hot Melt Adhesive
Many of our clients may ask us what’s the difference between the PUR adhesive and traditional EVA Hot melt adhesive? Both are hot melt adhesives; their features may sound similar. However, according to the manufacturing process, the theory of chemical reaction, and performance, they are actually different types of adhesive! In this article, we would like to compare them from all aspects to assist our client find out which the most suitable product is.
Performance after Lamination
PUR has outstanding adhesion to a wide range of materials. EVA hot melt adhesive may also cure fast on the substrate, but when it comes to adhesion it is mostly weaker than PUR. The most amazing feature of PUR is that it may laminate more challenging substrates with strong adhesion and flexibility. Because of this feature, PUR can be widely used in the textile field, especially the lamination of high water repellent fabric. Although the price of PUR in kilogram is expensive than EVA hot melt adhesive, in the same application, PUR requires less adhesive and comes with better performance! On this point, PUR is so vastly superior to EVA hot melt adhesive
Compared with EVA hot melt, PUR has better weather resistance. Extremely cold temperatures provide problems for EVA hot melt adhesive, the subject will crack and brittleness easily. In the circumstance of 70°C to 90°C, it will start to melt. Those problems will not occur on PUR, it can survive in the lower temperature and the heat resistance is up to 176°C.
EVA hot melt adhesive: Mostly the curing time of EVA hot melt adhesive is from 5 seconds to 30 seconds. However, when the temperature goes higher above 80°C, EVA hot melt adhesive would melt again.
PUR adhesive: According to different applications and processes, the curing time may be from 5 seconds to 1 minute above. Furthermore, PUR can be reacted with the moisture in the air; its strength of adhesion will continue to increase during the time. Usually, PUR requires about 24 ~ 48hours of completing the chemical curing totally.
EVA hot melt: It can be melted again as long as it is heated, so it is not necessary to be cleaned with a specific cleaner.
PUR adhesive: Different from EVA hot melt, the chemical reaction of PUR adhesive is irreversible. To extend the lifetime of the machine, the clean-up process is necessary after each time you use the machine. Now there are two kinds of cleaner in the market, liquid type, and solid type. Here is the process: purging with a small quantity (0.5kg) of PUR cleaner, and running the roller for 10 minutes at 100 – 120°C with the cleaner for 3~4cycles. Using a wire brush if necessary, and then drain and wipe clean.
EVA hot melt adhesive: Usually EVA adhesive may have a shelf life of up to 2 years at room temperature.
PUR adhesive: Depending on different packaging methods, they have a different shelf life. Some manufacturers will inject nitrogen into the packaging process to extend the shelf life. Usually, the shelf life will no longer than 12 months.
As with anything, both advantages and disadvantages must be weighed out before making a decision. If you still have any questions about adhesives, please feel free to ask our expert right now!
EVA hot melt adhesive VS PUR adhesive
|EVA hot melt adhesive||PUR adhesive|
|Performance after lamination||△||◎|
|Curing time||5~30 seconds||24 hours completing the chemical curing|
|Clean-up process||X||Using PUR cleaner|
|Shelf life||2 years||12 months|
For more information about PUR please click here.