Will hot melt adhesive not stick after a long time of use?

When the hot melt adhesive is not used up for a long time, it may cause it to not stick or even have no stickiness. Hot melt adhesives that have not been used under normal circumstances also have a certain shelf life, and can generally be stored for about 1-2 years. Of course, it is recommended to use up the melted hot melt adhesive as much as possible during use. So let’s take a brief look at the reasons that can easily cause hot melt adhesive to not stick!

1. Shelf life
   Once any product is produced, it will have a shelf life. Hot melt adhesive is no exception. Under normal circumstances, it can be stored properly without the influence of external factors. The shelf life of hot melt adhesive is relatively not a problem. But the key still lies in the storage method of hot melt adhesive. If purchased and stored improperly, it will also shorten the service life.
2. Repeatedly using the same pot of glue
   If there is a high demand for hot melt adhesive, it is recommended to calculate the usage amount before applying the adhesive. It’s best to melt as much as needed. Avoid leaving unused hot melt adhesive in the pot for a long time, as it can affect viscosity and cause waste. Of course, there is another factor. If hot melt adhesive is repeatedly heated, it is easy to form carbides, which can lead to an increase in colloidal impurities and affect the performance of the adhesive, resulting in non adhesion. Here is a small method to teach everyone: if there is really a shortage of glue, it needs to be stored for the next time. It is recommended to add some new hot melt glue and mix it before the next heating use to enhance viscosity.
3. Hot melt adhesive spoilage due to prolonged storage time
   In fact, users who purchase hot melt adhesive sometimes cannot avoid storing unused hot melt adhesive in the warehouse. Over time, when used again, it may feel that the bonding effect is not as good as before. This is because the storage of hot melt adhesive in different environments can affect its performance. Dust, microorganisms, and moisture in the air can easily cause damage to the internal molecules of hot melt adhesive, leading to a change in the properties of the adhesive and different changes during use.
   For example, if hot melt adhesive infiltrates too much water, the water will vaporize and evaporate during melting. The water at a deeper position in the adhesive is easily locked and cannot be released into bubbles. At this time, if the adhesive is extruded, it will be discharged into the air together with the bubbles, and the area occupied by the bubbles will form a void above the extruded adhesive, which is the empty adhesive gap. Of course, if the dust penetrates too much, it will increase the amount of colloidal impurities and make it difficult to stick. And once these situations occur, many users will unanimously believe that the glue is not sticky!
   But in fact, it may not necessarily be a problem with hot melt adhesive. The storage environment and usage methods can both affect the effectiveness of the adhesive.
   So when storing hot melt adhesive, it is necessary to seal the opening properly. If it is not sealed properly after use, it will be affected by the environment, climate, and temperature and humidity, and it cannot be guaranteed that the hot melt adhesive will stick well again in the next use.
   So the usage cycle time is not a direct problem that makes the hot melt adhesive not stick, but it cannot avoid being the cause of the problem. Losing stickiness cannot occur in a short period of time, it is inevitably influenced by certain factors. I suggest that if the hot melt adhesive is not used for a long time, it is recommended to clean the adhesive furnace before adding new hot melt adhesive.