The reason why the adhesive layer is easy to break is related to the force and the physical properties of the hot melt adhesive. In the final analysis, it is convenient to find the corresponding solution with the hot melt adhesive.
Why does the magnitude of stress affect the fracture of the adhesive layer? Normally, the glue has a certain penetration to the surface of the substrate when the glue is applied, and the glue is also constantly dissipating and drying, and eventually forms a layer of glue. The adhesive layer after adhesion has a certain peel strength and toughness, can withstand a certain amount of tension and pressure, so that the adhesive part is not affected by external forces to show the firmness is very reassuring. However, sometimes some products need to receive the test of tension and pressure. If the adhesive layer and the substrate surface fusion degree is good enough, the adhesive layer can use the toughness of the substrate to improve their resistance capacity. But if the adhesive layer is forced to appear local detachment, only by the resistance of the adhesive layer itself, there may be fracture.
In addition, some soft hot melt adhesive is conducive to improving its resistance ability, thus resisting the risk of adhesive layer fracture. The hot melt adhesive with soft colloid also has a certain resistance toughness after coating, just like a rubber band, and it is not easy to break off when stretched. Similarly, the thin consistency of such hot melt adhesive itself will be lower, easier to penetrate the material, permeate enough, the adhesive layer on the material to form a certain dependence, the hardness of the adhesive layer is also helpful. When the adhesive layer is stressed, the soft adhesive layer can offset some strength, coupled with good penetration without partial detachment, the adhesive layer can still be well attached to the material surface.
In the same product sometimes need to glue on multiple parts, some parts are relatively closed, some parts are easy to force, then it is necessary to consider whether the current use of hot melt glue can adapt to the bonding requirements of all parts. If you just want to use a hot melt adhesive to complete the bonding of all parts of the work, it is necessary to choose the hot melt adhesive with the adhesive requirements of the more difficult bonding parts, in order to avoid causing a good adhesion, another place where the adhesive layer fracture, bounce off and other phenomena.