Quality control of the most popular wireless adhes

2022-08-26
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Quality control of wireless adhesive binding

correct use of raw materials

1 Strictly control the temperature of hot melt adhesive

at present, all EVA hot melt adhesive is used in the production of paperback adhesive binding. In actual use, the service temperature of hot melt adhesive must be strictly controlled. Generally, the temperature of back glue should be controlled between 150 ~ 170 ℃, and the temperature of side glue should be generally controlled between 100 ~ 120 ℃

this is because when the temperature is too high, although the fluidity and permeability of the hot-melt adhesive are increased, the viscosity and strength of the hot-melt adhesive are reduced, and the adhesive layer cannot be formed on the back of the book well, and the bonding strength of the book will also be reduced. In serious cases, there will be page falling, scattering, glue breaking and other phenomena; If the temperature is too low, the hot melt adhesive will thicken, and its coating will not be very uniform. In particular, the hot melt adhesive cannot be completely poured into the broaching part, which is very easy to cause page loss. It is mainly composed of "ghost fishing gear" and scattered pages

the above mainly refers to the problem of back glue. The side glue is also closely related to the change of temperature. The temperature is low, the glue coating layer is thick, the back of the book is thick after passing through the holder, there are defects such as glue overflow, and the temperature is too high, there are defects such as weak adhesion and no side glue. These are formed because the fluidity and viscosity of the hot melt adhesive change when the temperature changes. Specifically, the temperature is inversely proportional to the viscosity, In direct proportion to liquidity. For the change of the environment, we should analyze the specific problems, not copy mechanically, but adjust the glue temperature realistically. For example, the glue temperature used in winter and summer must be different

2. Select the appropriate hot melt adhesive

the hot melt adhesive should be visually inspected before use. A good hot melt adhesive should be the film bright and translucent. There will be no large deformation after folding back and forth with two hands, and there will be no large deformation after hitting with a small hammer

secondly, the cold and hot detection should be carried out. The cold detection is mainly placed in the environment of -10 ~ 20 ℃. After a period of time, we should see whether it has toughness and can adapt to the cold in winter; The thermal test is mainly to put it in the environment of 40 ~ 50 ℃ to see how well it solidifies and whether it can adapt to the heat of summer

finally, the specific gravity test is carried out. The simple method is to add hot melt adhesive to the graduated measuring cup, and then add water to provide a high-quality platform for exchange, learning and cooperation in the industrial field. Different volumes and weights are measured to calculate the specific gravity. Practice has proved that when the specific gravity test result of hot melt adhesive is 0.7 ~ 0.72 tons/cubic meter, the application effect is better, and the formula of hot melt adhesive is also more reasonable

(to be continued)

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