With the continuous improvement of economic level, PE protective film is widely used, and its arrival has brought great convenience to our lives. Sometimes, we may find that the PE protective film leaves residual adhesive. What is the reason for this? Today, let's talk about the reason for the residual adhesive left by the PE protective film.

1. Aging mechanism

The main chain of acrylic pressure-sensitive adhesive is a saturated chain, and it is difficult to break the main chain with general heat energy. The aging mechanism is mainly UV aging; The aging of the substrate is mainly caused by ultraviolet light aging. The tensile strength of PE film substrate after aging under 30W ultraviolet light from the UV lamp supplier at 80 ℃ for one week shows that the usual operating temperature has little effect on its aging performance, while the influence of ultraviolet light is significant. But under the dual effects of heat and ultraviolet light, there is a synergistic aging effect.

2 Similar compatibility mechanisms

Acrylic pressure-sensitive adhesive belongs to materials with high polarity, and is compatible with polar materials such as acrylic, polyester, polyurethane, etc., which makes it difficult to remove the PE protective film. Sometimes, small molecules in pressure-sensitive adhesives that have not participated in cross-linking will accumulate on the surface. If the protective surface material has a strong effect on these small molecules, the phenomenon of small molecule migration and residue may occur.

3. Changes in peel strength over time

No matter how high the surface glossiness is, there are many tiny holes scattered on the surface of the 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 in the polymer parts that have not participated in cross-linking.

As time goes by, the pressure-sensitive adhesive gradually penetrates into the gap, forming an "anchor". In addition, when attaching the PE protective film, although the pressure is high, the contact area between the pressure-sensitive adhesive and the outer surface of the material is not very large. With the extension of time, the contact area gradually increases, and the effect force between the PE protective film and the protected outer surface also gradually improves. Both effects will increase the peel strength over time.