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Practical adhesive properties of water-based pressure-sensitive adhesives
The water-based pressure-sensitive adhesive has its own viscoelasticity and good wetting properties on the outside of the adherend, which provides the pressure-sensitive adhesive characteristics of external pressure-sensitive adhesive tapes.
The initial adhesion is also called fast adhesion, which means that when the water-based pressure-sensitive adhesive surface of the pressure-sensitive adhesive tape and the outside of the adherend are fought with a light pressure, they immediately enter the respective capabilities to resist the respective abilities. As usual, the so-called tackiness of the pressure-sensitive adhesive surface when you slightly touch the pressure-sensitive adhesive surface with your fingers and immediately remove it. This is a suitable bonding function unique to pressure-sensitive adhesive tapes.
The cohesive force of water-based pressure-sensitive adhesive refers to the ability to resist the adhesive interface between the pressure-sensitive adhesive tape and the surface of the adherend after the application of appropriate external pressure and time has stopped. As usual, peel strength experiments of pressure-sensitive adhesive tapes are used to stop measurement and characterization.
Adhesive force refers to the adhesion force between the pressure-sensitive adhesive and the substrate, or the pressure-sensitive adhesive and the primer, and the primer and the substrate. The complete adhesive layer and the substrate occur in the pressure-sensitive adhesive tape stop peel strength test. The peel strength value measured at the time of disengagement can be regarded as the size of the adhesive force. Under abnormal conditions, the pressure-sensitive adhesive force of the pressure-sensitive adhesive is greater than the force of the adhesive force, so this value is helplessly measured.
In the applicable pressure-sensitive adhesive tape, the pressure-sensitive adhesive tape is supplied in a reel shape. At this time, the water-based pressure-sensitive adhesive is attached to the back of the substrate and protected, and the water-based pressure-sensitive adhesive in the pressure-sensitive adhesive sheet is affixed Protected against the release layer of the paper or film. It is necessary to unwind the roll of pressure-sensitive adhesive tape or peel off the paper (or film). Therefore, the adhesion between the water-based pressure-sensitive adhesive and the substrate or the release layer of the paper (or film) is also one of the important applicable bonding functions of the pressure-sensitive adhesive tape. This type of adhesive function is usually measured and characterized by the unwinding force test of a pressure-sensitive adhesive tape or the peel force test of a pressure-sensitive adhesive on a release paper (or film).
In addition, the adhesion between the water-based pressure-sensitive adhesive and the back of the substrate or the release layer of the cut-off paper should also be maintained within an appropriate range. If this kind of adhesion is too strong, it will be difficult when the pressure-sensitive adhesive tape is unrolled or the adhesive sheet is peeled off the paper (or film), and even signs such as sticking back or tearing the paper (or film) will occur. . If this kind of adhesion is too small, the environment where the pressure-sensitive adhesive tape is stored, transported, and applied may be loosened or the paper (or film) sunk.