The difference between cold glue and hot glue of hot melt adhesive can not be distinguished.
The difference between hot-melt adhesive and cold-adhesive is the difference in physical properties between the two states. From the description of the two bonding methods, it is well understood that the difference between the two will be more convenient for the future.
First, cold sticky: in many pressure sensitive hot melt applications, will be encountered. Among them, the coke bag seals used for packaging and wrapping are glued by hot melt adhesive. Because you don't know when the courier bag will be used, you can apply the hot melt adhesive with the initial tackiness to solve the problem of ready-to-use. Moreover, the cold stick does not have a glue overflow, and there is not much damage to the surface of the substrate. As long as the adhesive layer is in contact with the substrate and the adhesive position is gently pressed, the adhesive layer can be tightly adhered to the substrate, and the tear can not be pulled off.
Second, hot sticky: in wood edge banding, book binding, carton paste bottom and other applications are very common. Similar substrates have certain requirements for the adhesion of hot melt adhesives, and the pressure sensitive adhesives do not achieve the desired bonding effect. Therefore, the thermal bonding method is used to enhance the degree of fusion between the colloid and the substrate. Moreover, like the texture of the surface of the board, the slits leave a space between the glue layer and the substrate, and the gap will contact the moisture and dust in the air, thereby greatly reducing the adhesion of the hot melt adhesive to the substrate. Over time, the glue layer will break away. Therefore, by heating the melted glue, the fine seam on the surface of the substrate can be well filled, and the glue can be more perfectly contacted with the substrate, thereby improving the bonding effect.
Third, the difference between cold adhesion and hot adhesion: they are solved in different areas of adhesive application, on the difference in their application, the degree of activity of the glue molecules is different. The hot-melt adhesive is used in the cold-bonded state, and the glue liquid has been cooled to become a solid, the molecular structure has become relatively stable, and it is convenient to stick and use; and the hot-melt adhesive is used in the hot-viscous state, and the molecules become active due to the heat of molecules. The ability to impact the molecular structure of the surface of the substrate, even in combination with the molecular structure of the substrate, shows that the hot tack is more likely to damage the surface of the substrate.
There are few substrates that can be used with both hot and cold tacks, and there is no need to wonder and choose between these two adhesive methods. Different substrates are not suitable for cold bonding, or they are suitable for hot bonding. As long as you understand the sensitivity of the substrate to hot melt adhesives, you know what kind of sizing method it is suitable for.