Cohesive strength of PUR hot melt adhesive machine

The law of influence between the cohesive strength of PUR hot melt adhesive colloid and wire drawing is: if the cohesive strength is large, the wire drawing phenomenon will be obvious; on the contrary, if the cohesive strength is small, the wire drawing phenomenon will not occur.

PUR hot melt adhesive curing time

The curing time of PUR hot melt adhesive is an important factor affecting the occurrence of stringing. Generally speaking, the PUR hot melt adhesive with a short curing time has a low probability of stringing, because the filaments formed when the hot melt adhesive is sprayed out of the muzzle, due to Rapid curing makes it impossible to stretch continuously and is prone to breakage, and sometimes no strands are visible.

Effect of machine temperature

If the PUR hot melt adhesive machine temperature is too low, the consistency of the PUR hot melt adhesive itself will increase and stringing will occur.

PUR reactive hot melt adhesive should be bonded within the opening time after application to ensure the best bonding effect. However, during the bonding process, bubbles may appear. What is the reason?

1. The temperature of the glue tank is too high. If the temperature is too high and the hot melt adhesive has poor heat resistance, this phenomenon may occur;

2. The hot melt adhesive itself. The hot melt adhesive is not completely melted and mixed during the production process. The air in the rubber will be released during the heating process by the user, or the hot melt adhesive is not vacuumed or cannot be vacuumed properly during the production process. thorough;

3. If there are bubbles in the glue coming out of the nozzle, you can consider whether the temperature of the hot melt glue machine is too high and whether there is residual glue that has not been drained out. You can try to drain the glue for a few minutes to see if the glue is smooth and without bubbles;

4. There are no bubbles when the glue comes out of the nozzle, but there are bubbles after the reaction. One possibility is that there is tension after bonding, and the external pressure is not strong enough, or the pressure is not good. Another possibility is that the adhesive was not positioned and pressed in time after pasting, causing it to bounce off when first bonded, resulting in bubbles on the edges or both ends.