The glue with good performance also has a large change in melt viscosity with temperature. Specifically: when the use temperature rises above 150 degrees, the melt viscosity of the glue can be quickly reduced, so that the coating can maintain proper permeability; and when the temperature of the glue is lowered, the viscosity of the glue can quickly increase. , and quickly solidifies, thus ensuring the effect of rapid limb binding. Hot melt adhesives can maintain good permeability only if they have a suitable melt viscosity, which is very important for Glue Binding. But too low melt viscosity will cause insufficient amount of glue on the back of the book. The melting degree of hot melt adhesive is more suitable in the range of 4000-5000 centipoise. Good adhesion and penetration performance, that is, when the equipment is running at high speed, the glue must be able to quickly infiltrate the spine of the book, and have excellent cohesion, which can ensure "no wire drawing", and will not crack or fall apart after cooling. In order to achieve this goal, changing the composition of the glue is one aspect. The key is to improve the cohesion and toughness of the base resin, and to introduce strong adhesive force, hard quality, low melt viscosity into the composition, and when the temperature changes up and down, Resins that dissolve or set rapidly. Adhesives with good performance should also have good tensile strength. The phenomenon of loose pages, falling pages, and breaking during the use of adhesive books is directly related to the tensile strength of hot melt adhesives. The tensile strength is usually 20-30kg/cm2. Hot melt adhesives must have good elongation. The elongation at break is high, and the toughness of the hot melt adhesive is good; only with good toughness can the book not be easily broken. The elongation requirement is greater than 300%
