1. Analysis of the time variation mechanism of peeling strength
No matter how high the surface gloss is, there are many tiny holes that can hardly be seen by the naked eye. Although the pressure sensitive adhesive is cross-linked, it still has certain deformation and fluidity, especially the polymer part which does not participate in crosslinking. As time goes on, the pressure sensitive adhesive gradually penetrates into the gap and forms an anchor. In addition, when the PE protective film is attached, the contact area of the pressure sensitive adhesive and the surface of the material is not very large, but the contact area increases with the time, and the force between the PE protective film and the protected surface is gradually increased. The two effects will increase the peel strength with time.
2. Analysis of aging mechanism
The main chain of the acrylic pressure sensitive adhesive is the saturated chain, and the general heat energy is difficult to break the main chain. The aging mechanism is mainly ultraviolet aging, and the aging of the base material is mainly ultraviolet light aging. The tensile strength of PE film substrate at 80 centigrade and 1 weeks after aging under 30W UV light was tested. The results showed that the usual use temperature had little effect on its aging properties, but the effect of UV light was larger. However, under the dual action of heat and ultraviolet light, there is synergistic aging effect.
3. Analysis of the compatibility mechanism with the protected surface materials
Acrylate pressure sensitive adhesive (PSA) is a very large material, which is easy to be compatible with acrylate, polyester, polyurethane and other polar materials, which causes the PE protection film to be uncovered. Sometimes the small molecules that are not involved in the pressure-sensitive adhesive are enriched to the surface. If the force between the protected surface materials and these small molecules is larger, there will be a phenomenon of small molecular migration.
Wuxi Shengfa Protection Film Co., Ltd