Petroleum resin is the main by-product of ethylene plant, which has good bonding performance and is widely used in hot melt adhesive. This paper describes the effect of petroleum resin on the adhesive properties of hot melt pressure sensitive adhesive.
The main factor affecting the bonding strength of hot melt adhesive itself is the compatibility between elastomer and petroleum resin. In other words, if the compatibility is good, the actual quantitative index of the colloidal energy storage film will be reduced to a certain extent, and the full adhesion between the two will be promoted under the action of stress. However, if the compatibility between the two is poor, the quantitative index will be improved, which will have a negative impact on the bonding effect between the colloid and the object requiring bonding treatment. In fact, if the elastomer is incompatible with petroleum resin or has poor compatibility, it is easy to increase the viscosity of petroleum resin and reduce the continuous bonding strength on this basis, thereby weakening the tackifying effect of petroleum resin itself. Generally speaking, if the wax fog point index increases, the adhesive strength of the resin will also increase, but at the same time, the initial adhesive strength will be reduced to a certain extent. If a scientific, reasonable and efficient process is adopted, and the softening point is controlled at more than 100 ℃, and the wax fog point is less than 90℃, a pressure-sensitive adhesive with high temperature shear strength and good performance will be produced, and then the application field of petroleum resin will be continuously expanded.
The softening point is generally determined by two aspects, one is the relative molecule of petroleum resin, the other is the resin structure. The higher the relative molecular weight of the resin, the greater the proportion of the resin ring structure, and to a certain extent, the softening point of the resin itself will continue to increase. Softening point plays an important role in the performance of hot melt adhesive, which is mainly reflected in the influence on the continuous bonding strength. The softening point is directly proportional to the cohesive strength of petroleum resin and determines the continuous bonding strength of the adhesive. In this case, it can not only significantly improve the temperature during the application of hot melt adhesive, but also expand its application range. Therefore, the softening point of the resin should be improved to the greatest extent, and at the same time, it should be well controlled to prevent too high softening point from affecting the wetting effect and melt viscosity of hot melt adhesive. Practical experience shows that in order to completely prevent colloidal hardening and colloidal scaling, it is most scientific to control the softening point at 80-130 ℃.
In order to meet the application requirements of hot melt adhesive industry in China, the research on petroleum resin should be continuously strengthened. Therefore, attention should be paid to exploring the application of petroleum resin in hot melt pressure sensitive adhesive.