Why is hot melt glue sticky in the day, cold and not sticky?
Published on Nov. 12, 2019
The hot melt adhesive is made of a polymer material, and the stability of its properties also varies with the degree of stability of the molecule. Weather factors often have subtle effects in the production of hot melt adhesives. The heat of the sky and the coldness of the sky all have a direct effect on the molecules of matter, which causes the hot melt adhesive to be sticky and sometimes not sticky. There must be some reason for this to be analyzed, and then the countermeasures for losing the sticky force can be solved.
When a hot melt adhesive is used on a hot day, the glue will be thinned by heat and its internal molecules will swell. Based on the same sizing method and penetration principle, the hot melt adhesive has better adhesion on the surface of the material. This is because after the surface of the adherend receives a certain amount of glue, the glue is quickly cooled to a solid, but its molecules still have a certain heat due to the influence of temperature, resulting in a larger molecular volume than normal temperature. When the adherend is adapted to the adhesion of the hot melt adhesive of a large-sized molecular structure, the adhesive layer is not detached as long as the state of both the adhesives is maintained. However, when the temperature drops, the low temperature causes the molecules inside the solidified rubber block to shrink and shrink, and the molecules of the hot melt adhesive and the molecules of the adherend become less tight, which causes unstable conditions in the bonded state. In such an unstable adhesive state, if the glue does not form as much penetration as the adherend during the previous gluing process, the low temperature is highly likely to cause the bond to collapse. When the weather is cold, it is the reason why the hot melt adhesive becomes non-sticky.
Hot Melt Glue
Thermal expansion and contraction are physical properties, and hot melt packaging adhesives can not be avoided. How to deal with the strange phenomenon that the heat of the day is sticky and the weather is cold and not sticky? This involves performance issues with hot melt adhesives. You can see the hot melt adhesive on the market, whether it is not resistant to low temperature or high temperature. Is there any hot melt adhesive that is both high temperature resistant and low temperature resistant? If so, does it solve the problem that the sticky hot-melt adhesive in the summer has gone to the winter, and it loses its adhesion and breaks away? It is a pity that there is no hot melt adhesive that meets this condition for the time being! Even if there is, the performance of this hot melt adhesive will not be good, because in order to maximize its performance, it must be developed in a targeted manner under specific requirements. Therefore, when the weather is hot, the hot melt adhesive of the summer formula is used, and the hot melt glue of the winter formula is used when the weather is cold, which is a relatively common habit of hot melt adhesive.
There are many reasons why hot melt adhesives used for shoe are not sticky. It depends on what factors affect their performance. Temperature is one of the most common causes. Buying suitable glue sticks for the season in different seasons is not only a hot melt adhesive manufacturer. For users of hot melt adhesives, it is also necessary to have a certain understanding of this aspect. Try to avoid because the hot melt adhesives are not selected. And caused a problem with the product.