How to properly preheat hot melt adhesive for books and periodicals?

1. Add glue

It is normal to add the adhesive appropriately according to the amount of adhesive used and the size of the hot melt glue pool. During use, maintain the liquid level in the sol pool within the range of 35% -80%. In general, the liquid level can be controlled at 50%. Otherwise, the hot melt adhesive will be repeatedly melted, causing waste of electrical energy, and during the melting process, the hot melt adhesive for books and periodicals will be subjected to local repeated high temperatures from the heating tube, leading to partial denaturation.

2. Preheating

Solid hot melt adhesive must be preheated before use. Preheat to liquid state before use. The temperature setting should not be too high, as the initial state melts slowly, especially for hot melt adhesives used in books and magazines. Partial decomposition occurs above 205 ° C. There are two heating methods for existing equipment, one is oil bath heating; Another type is electric heating plate heating. In terms of performance, oil bath heating is better, and its advantage is temperature stability. The direct heating market share of electric heating plates is relatively high, basically reaching over 80%. The reason is that the structure is simple and the cost is low. Its disadvantage is uneven temperature. When the melted glue carbonizes, especially when the glue temperature is too high, the impact in this regard is greater. The preheating time is generally 2 hours, and the center temperature is set at 180-160 ℃.