Hot melt adhesive (English name: Hot Glue) is a plastic adhesive. Its physical state changes with temperature within a certain temperature range, and the chemical properties do not change, and it is non-toxic and tasteless, and is an environmentally friendly chemical product. Hot melt adhesives are popular because their products are solid, easy to pack, transport and store, solvent-free, pollution-free, non-toxic, and have simple production process, high added value, high bonding strength and fast speed. Factors affecting the adhesive and its strength 1. Interface damage: the adhesive layer is completely separated from the adhesive surface (the adhesive interface is completely detached); 2. Cohesion damage: the damage occurs in the adhesive or the adhesive itself, not between the adhesive interface; 3. Mixing damage: the adhesive and the adhesive layer itself are partially damaged or only one of the two.