Silicone pressure-sensitive adhesive is a special adhesive composed of silicone resin (MQ silicone), silicone rubber, catalyst, cross-linking agent and other additives. Silicone pressure sensitive adhesives mainly include solvent type, high solid content type, solvent free type, emulsion type, radiation curing type, resin modified type, biodegradable type and functional type system.

Because the solvent type contains a lot of volatile organic compounds, it is easy to cause serious environmental pollution when curing. Nowadays, more and more attention has been paid to environmental protection. The silicone pressure-sensitive adhesive industry is taking environmental protection and low-cost products as the mainstream of development, and taking new products such as biodegradation and radiation curing as the research direction. MQ silicone resin mainly plays the role of tackifying and reinforcing. The silicone hydroxyl or vinyl in MQ resin can respectively react with the hydroxyl of silicone rubber or with silicone rubber through hydrosiloxane under the action of catalyst to prepare silicone pressure-sensitive adhesive.

The indexes to measure the adhesion performance of pressure-sensitive adhesive are: tack T, adhesion a, cohesiveness C and keying K. in order to make pressure-sensitive adhesive with excellent performance, it is necessary to consider how to make the four kinds of adhesion meet the following balance relationship: k > C > a > t. The results show that the ratio of silicone to rubber has the greatest influence on the performance of pressure sensitive adhesive. With the increase of silicone content, the cohesion of pressure sensitive adhesive increases, but the peel force decreases; with the increase of silicone content, the initial viscosity increases, but the holding viscosity decreases. This is because silicone rubber can increase the fluidity of pressure-sensitive adhesive, thus increasing the interface adhesion and the initial adhesion; the reduction of resin content is not conducive to deep cross-linking, the reinforcement effect is not good, and the cohesion is reduced. MQ resin molecular weight has a great influence on the adhesion performance of pressure-sensitive adhesive, because the change of molecular weight changes the viscosity and cohesive strength of pressure-sensitive adhesive. When the molecular weight is high, the cohesive strength of PSA is high and the viscosity is good; when the molecular weight is low, the bulk viscosity is low, which can improve the interfacial adhesion, but the cohesive strength of polymer is low, which is easy to occur cohesive damage when peeling off. When the molecular weight distribution of MQ resin is wide and the number average molecular weight is about 3000, MQ resin can be used to prepare pressure-sensitive adhesive. Nicolas studied the adhesion of acrylic adhesive to siloxane elastomers with different quality MQ silicone resin to adjust the mechanical properties (mainly peel strength). The results show that the amount of MQ silicone resin in the elastomer has a great influence on the performance of the modified tape, and controlling the surface performance of the elastomer is an effective way to adjust the peeling force.