PUR hot melt adhesive compared with water-based pressure sensitive adhesive
1.Why do I often encounter yellow spots when brushing when I make white materials?
First of all, this is caused by the white material itself or contamination by the adherent. The water-based PU adhesive will not yellow. In the market, we usually encounter white PU / PVC bonded to rubber. Because the treated water used for rubber contains strong oxidizing substances. Because the glue is oxidized when it is covered by it, yellowing occurs. At this time, the method is to prevent the medicine from overflowing when processing the rubber of the substrate, and clean up in time if there is any overflow.
2, why is the viscosity worse in autumn and winter than in summer?
This is caused by failure to follow correct operating practices. In addition, this problem is related to the performance of the product's viscosity retention time. In summer, the temperature is high, and it can be bonded without abnormality within 3 'after drying. In autumn and winter, the temperature is relatively low, and the cold air directly glues the surface, which shortens the viscosity retention time of the glue. At this time, it cannot be operated in summer. The conditions are appropriately changed and used properly.
PUR hot-melt adhesive has the following advantages compared with EVA hot-melt adhesive, water-based pressure-sensitive adhesive, and solvent-based adhesive:
Solvent-free, one-liquid type. Unlike solvent-based adhesives, which require a drying process, there is no environmental pollution and poisoning problems due to solvents, which meets environmental protection requirements. The bonding process is simple and can use sizing methods such as roller coating or spraying.
Good operability. The two adherends can be fixed in a short time, so the assembly can be quickly transferred to the next processing process, which improves the work efficiency.
Excellent heat resistance, cold resistance, water vapor resistance, chemical resistance and solvent resistance. Compared with the original hot-melt adhesive, due to the cross-linked structure of the reactive hot-melt adhesive, the listed properties and adhesive strength are greatly improved.