Analysis of the Causes of Residual Glue in PE Protective Film
2025/6/13 11:33:45 72
1. Analysis of the time-varying mechanism of peel strength
No matter how high the surface gloss is, there are many tiny holes distributed on the surface of an object that are difficult to see with the naked eye. Although pressure-sensitive adhesives have undergone cross-linking, they still have certain deformation and fluidity, especially the polymer part that has not participated in cross-linking. As time goes by, the pressure-sensitive adhesive gradually penetrates into the voids, forming an "anchor". In addition, when applying the pe protective film, although the pressure is relatively high, the contact area between the pressure-sensitive adhesive and the material surface is not very large. As time goes by, the contact area gradually increases, and the interaction force between the pe protective film and the protected surface also gradually improves. Both effects will cause the peel strength to increase over time.
2. Analysis of aging mechanism
The main chain of acrylate pressure-sensitive adhesive is a saturated chain, and it is difficult for general thermal energy to break the main chain. The main aging mechanism is ultraviolet light aging. The aging of the substrate is mainly due to ultraviolet light aging. The author once tested the tensile strength of PE film substrates after aging for one week in an environment of 80 ℃ and under 30W ultraviolet light. The results showed that the normal operating temperature had little effect on its aging performance, while the influence of ultraviolet light was significant. However, under the dual effects of heat and ultraviolet light, there is a synergistic aging effect.
3. Analysis of compatibility mechanism with the protected surface material
Acrylate pressure-sensitive adhesives are materials with relatively high polarity and are easily compatible with polar materials such as acrylate, polyester, and polyurethane, making it difficult to remove the pe protective film. Sometimes, the small molecules of the pressure-sensitive adhesive that do not participate in crosslinking will accumulate on the surface. If the interaction force between the protected surface material and these small molecules is relatively large, the phenomenon of small molecule migration and residue will occur.
4. Mechanism Analysis of viscoelastic effect
Pressure-sensitive adhesives belong to viscoelastic materials and undergo elastic and plastic deformations under the action of external forces. When the force application speed is fast, elastic deformation plays a major role. When the force application speed is slow, plastic deformation plays a major role. If the protective film is removed quickly, the pressure-sensitive adhesive will undergo elastic deformation, and the pressure-sensitive adhesive in contact with the protected surface will not be able to separate from the surface in time, resulting in residual adhesive. According to the principle of time-temperature equivalence, the effect of removing the protective film at low temperatures is similar to that of removing it quickly.