Analysis of why PE protective film has residual glue
Jul 29, 2022
With the continuous improvement of economic level, PE protective film is widely used, and its arrival brings convenience to our life. We need to use it in the right way. Sometimes, we will find the problem of residual glue left by PE protective film. What is the reason for this? Let us talk about the reason why PE protective film leaves residual glue.
1. Changes in peel strength over time
No matter how high the surface gloss is, there are many tiny pores on the surface of the object that are difficult to see with the naked eye. Although the pressure-sensitive adhesive is cross-linked, it still has deformation and fluidity, especially the polymer part that is not involved in the cross-linking.
Over time, the pressure-sensitive adhesive gradually penetrates into the voids to form "anchors". In addition, when the pe protective film is attached, although the pressure is large, the contact area between the pressure-sensitive adhesive and the material surface is not very large. With the extension of time, the contact area gradually increases, and the pe protective film and the protected surface The force also increases gradually. Both effects will increase the peel strength with time.
2. Aging mechanism
The main chain of acrylate pressure-sensitive adhesive is a saturated chain, and it is difficult for general heat to break the main chain. The aging mechanism is mainly ultraviolet light aging; the substrate aging is also mainly ultraviolet light aging. For example, the tensile strength of the PE film substrate after being aged for 1 week in the environment of 80°C and the UV lamp supplier's 30W ultraviolet light, the results show that the usual use temperature has little effect on its aging performance, while the effect of ultraviolet light but larger. However, under the dual action of heat and ultraviolet light, there is a synergistic aging effect.
3. Similar compatibility mechanism
Acrylic pressure-sensitive adhesives are highly polar materials and are easily compatible with polar materials such as acrylates, polyesters, and polyurethanes, making it difficult to remove the PE protective film. Sometimes the small molecules that are not involved in the cross-linking of the pressure-sensitive adhesive will be enriched on the surface. If the force between the protected surface material and these small molecules is large, the phenomenon of small molecule migration and residue will appear.
