Views:2 Author:Site Editor Publish Time: 2019-07-03 Origin:Site
It is well known that one of the most important performance indicators of hot melt adhesives is the adhesion to the substrate, to determine whether the hot melt adhesive is qualified, usually the first test is to test whether the alcohol soluble adhesive adhesion is up to standard. Formulation design, bonding base, substrate treatment, etc., which affect the adhesion of hot melt adhesives. In order to improve the bond strength of the colloid, the most common method is to add a tackifying resin to the formulation to enhance the colloidal bonding properties.
There are many varieties of tackifying resins, which can be divided into natural tackifying resins and synthetic tackifying resins according to the source, The most tackifying resins used in hot melt adhesives are rosin and its modifications, terpene resins, petroleum resins, alkyl phenolic resins and so on. The tackifying resin has good compatibility, can improve the cohesive force of the hot melt colloid, improve the adhesion to the surface of the substrate and the long-lasting adhesion. It is also possible to improve the fluidity of the colloid, thereby enhancing the collapsing ability and penetration ability of the colloid to the adherend to improve the bond strength.
If the tackifying resin is added too much, the strength of the hot melt granule will become low, the temperature resistance will be deteriorated, and the colloid will be self-adhesive, which is not conducive to production, processing, transportation and storage. Is there any other material that can improve the bond strength without affecting the properties of the hot melt adhesive?
Graft-modified materials are not ordinary physical blending, and are prepared by introducing high-activity functional group side chain monomers on different polymer backbones for different matrix resins (EVA, PE, PP, POE, ethylene propylene rubber, etc.). It provides solutions for difficult-to-bond substrates for different systems of hot melt adhesives, pressure sensitive adhesives and hot melt adhesive films. The grafting material has good compatibility and strong polarity, can significantly improve the bonding performance to the substrate, and does not reduce the strength and temperature resistance of the colloid, and can be used as a main resin.