Correct use of raw materials

1. Strictly control the temperature of hot melt adhesive

At present, all EVA hot-melt adhesives are used in the production of adhesives for paper-bound adhesives. The actual use temperature of hot-melt adhesives must be strictly controlled. Generally, the adhesive temperature should be controlled between 150 and 170°C. Should generally be controlled between 100 ~ 120 °C.

This is because when the temperature is too high, although the flowability and permeability of the hot melt adhesive are increased, the viscosity and strength of the hot melt adhesive are decreased, and the adhesive layer is not formed on the back of the book very well, and the binding strength of the book is also reduced. If the temperature is too low, the hot-melt adhesive will thicken and the coating will not be uniform. In particular, the hot-melt adhesive cannot be completely poured into the slot part. Can easily cause page breaks and loose pages.

The above mainly refers to the problem of adhesive, the side adhesive also has a great relationship with the temperature change, the temperature is low, the adhesive layer is thick, after the bracket is clamped, the back of the book is thick, there are defects such as glue overflow, and the temperature is too high. There are defects such as weak bonding, no side glue, etc. These are due to changes in the fluidity and viscosity of the hot melt adhesive when the temperature changes. Specifically, the temperature and viscosity are inversely proportional to the fluidity. It is proportional. For the specific changes in the environment to analyze the specific issues, can not be impersonated, to adjust the actual glue temperature, such as the glue temperature used in winter and summer is certainly a difference.

2. Choose the right hot melt adhesive

Before the use of hot melt adhesive first visual inspection, good hot melt adhesive film should be bright, semi-transparent, with two hands back and forth after folding will not have a large deformation, with a small hammer will not be too much deformation .

Secondly, cold and heat testing should be carried out. Cold testing is mainly conducted in an environment of -10 to 20°C. After a period of time, it can be seen whether it has its own toughness and can adapt to the cold in winter; thermal inspection is mainly conducted at 40 to 50°C. In the environment, see how solid it is and whether it can adapt to the summer heat.

Finally, the specific gravity test is performed. The simple method is to add hot melt adhesive to the graduated measuring cup, and then add water to measure the specific volume and weight. Practice has proved that when the hot melt adhesive specific gravity test result is 0.7 to 0.72 tons/cubic meter, the use effect is better. At this time, the hot melt adhesive formula is also reasonable.

(to be continued)