PUR hot melt adhesive compared to water-based pressure sensitive adhesive
1. Why do the areas that have been brushed with glue often turn yellow when making white materials?
First of all, this is caused by the white material itself or the contamination by the adherend. The water-based PU adhesive will not turn yellow. In the market, we usually encounter white PU/PVC and rubber bonding, because the treated water used for rubber contains strong oxidizing substances. , when the glue covers it, it is oxidized, so yellowing occurs. At this time, the method is to not spill the liquid medicine when dealing with the substrate rubber, and clean up the spillage in time.
2. Why is the viscosity worse in autumn and winter than in summer?
This is caused by not following the correct operating specifications. In addition, this problem is related to the performance of the product's viscosity maintenance time, etc. In summer, the temperature is high, and it can be pasted within 3' after drying without abnormality. In autumn and winter, the temperature is relatively low, and the cold air is directly on the glue surface, which shortens the viscosity maintenance time of the glue. At this time, it cannot be operated according to the summer. conditions are appropriately changed and used correctly.
Compared with EVA hot melt adhesive, water-based pressure-sensitive adhesive and solvent-based adhesive, PUR hot melt adhesive has the following advantages:
Solvent-free, one-component type. Unlike solvent-based adhesives, which requires a drying process, there is no environmental pollution and poisoning problems caused by solvents, and it meets environmental protection requirements. The bonding process is simple, and sizing methods such as roller coating or spraying can be used.
Good operability. The two adherends can be fixed in a short period of time, so the assembly can be quickly transferred to the next processing process to improve work efficiency.
Excellent heat resistance, cold resistance, water vapor resistance, chemical resistance and solvent resistance. Compared with the original hot-melt adhesive, the listed properties and bond strength are greatly improved due to the cross-linked structure of the reactive hot-melt adhesive.