Will the EVA hot melt adhesive stick after a
When the hot melt adhesive has not been used up for a long time, it may not be sticky or even lose its stickiness. Hot melt adhesives that are not used at room temperature have a shelf life, and hot melt adhesives that have been melted should be used up as much as possible at one time. Pay attention to their usage habits. Guangzhou HoriI hot melt adhesive manufacturer tells everyone:
1. Pay attention to the shelf life
Hot melt adhesives generally have a shelf life after they are produced. That is to say, if they are used within this shelf life, the influence of some external factors is excluded, and there is no problem in using hot melt adhesives. But the shelf life is relative, and it depends on how the hot melt adhesive is stored.
2. Repeated use of the same pot glue
It is not good to keep the hot melt adhesive that is not used up in the glue pot. It is best to estimate the amount of glue used before gluing, and melt as many kilograms of hot melt adhesive as needed, so that it is not wasted. Another advantage is that the hot melt glue that is avoided as much as possible will form carbides after repeated heating. More carbides equals more impurities, which will affect the performance of the glue and cause it to be non-sticky. Sometimes the glue that is not used up, before the next heating use, add some hot melt glue to mix it, pay attention to this little trick.
3. The hot melt adhesive has deteriorated after being stored for too long
Some users may not usually use a lot of glue, and the hot melt glue that has not been used has been stored in the warehouse. When it is necessary to use it, they find that the bonding effect is far different than before. What is the reason? Hot melt adhesives will be affected by different storage environments and lead to changes in their properties. For example, moisture, dust, microorganisms in the air, etc., will invade from the surface of the hot melt adhesive to its interior, destroying the molecular sequence inside. When this happens, the properties of the hot melt adhesive will change, and different physical changes can be seen during its use.
If the hot melt glue penetrates too much moisture, the moisture will vaporize directly when the glue is melted. The moisture in the deeper part of the glue is locked in the glue and cannot be released, and bubbles will be formed. When the glue is squeezed out, the bubbles are expelled together with the glue. At this time, the water vapor is released into the air, and the space occupied by the blisters is vacated on the extruded glue, forming what everyone calls the void. glue. If too much dust has penetrated, there will be more impurities in the glue, which is definitely not good. However, when there is a problem, many glue users summarize the problem as the glue is not sticky! Sometimes it is not necessarily the problem of hot melt adhesive itself, storage and use habits will also affect its use effect. Therefore, when storing the hot melt adhesive, it should be sealed as much as possible, and the opening of the box or bag should not be sealed until it is used up. No one can guarantee that the hot melt adhesive will stick well in the next use.
The long service life will not be the direct cause of the hot melt adhesive not sticking, but it will also be the cause of the problem. After all, the loss of stickiness will not happen all at once, it must be caused by some factors. If it is too long to use up, it is recommended not to use it again. The glue oven should be cleaned and the new hot melt glue should be refilled.