Why is ionic liquid rubber pressure sensitive adhesive studied?

Adhesives are widely used in People’s Daily life, providing a variety of conveniences for people’s life. Pressure Sensitive Adhesive (PSA) is a very important adhesive. Psa is very sensitive to pressure and can be strongly bonded to the adhesive by applying mild pressure without the need for solvent, heat, or other means.

Since the last century, the research and application of pressure-sensitive adhesive have been rapidly developed and has been widely used in all walks of life. Rubber-type pressure sensitive adhesive (RPSAs) is made of rubber elastomer as a matrix, with appropriate viscosifying resin, filler, softener, crosslinking agent, solvent, and so on. It is a kind of adhesive that can be closely bonded with the adhesive with small pressure.

It is widely used in single and double side adhesive tape, trademarks, labels, medical supplies and electronic products, and other fields. So far, there are several theories to explain the bonding mechanism, including adsorption theory, mechanical interlock theory, diffusion theory, and electrostatic theory. The bonding mechanism of pressure-sensitive adhesive is as follows: it will have viscous flow after being subjected to external pressure and can fully contact the substrate surface.

When the pressure-sensitive adhesive has sufficient wettability to the substrate surface, the molecules between the interface can contact closely and generate intermolecular force to achieve adsorption equilibrium and generate strong adhesion. The molecular weight of the rubber is usually higher, so it is necessary to add other additives, such as viscosities, softener, and solvent, to reduce the viscosity of rubber and increase the adhesive property of rubber. However, there are still some problems with rubber pressure-sensitive adhesive.

For example, rubber generally has a high molecular weight, so its viscosity is higher, despite the addition of a large number of viscosifying resins and softeners, but its initial viscosity is low; There are still unreacted double bonds in rubber elastomers, which are easy to age under the action of light and heat despite the addition of antioxidant. The glass transition temperature of some rubber is relatively high, and it is easy to fail at low temperatures. At the same time, after the preparation of the existing rubber pressure-sensitive glue, the edge of the PET film is partially coated with glue and partially without glue due to the uneven coating of pressure-sensitive glue. Therefore, the area not coated with pressure-sensitive glue needs to be cut and removed. However, the width of the cutting can not be determined according to the actual distribution of pressure sensitive adhesive, resulting in the normal part being cut, resulting in waste.