To start with, pressure-sensitive adhesive is a kind of adhesive. More precisely: the adhesive that is found on adhesive tape. Pressure-sensitive adhesives have a special formulation: They combine viscosity - the state of being thick, sticky, and semi-fluid in consistency like honey for example - with elasticity - like rubber has for example. They adhere well on a surface (adhesion) and are equally solid and stiff in and of themselves (cohesion). In order to achieve that, the adhesive substance must consist of specific raw materials.
For example, natural rubber can be added since it has especially strong adhesion through the inclusion of resins. Adhesive tape on a natural rubber basis is applied, for instance, when we need to cover surfaces for painting work or seal up boxes. If adhesive tape must stick for a particularly long time, withstand UV sunlight and extreme temperatures, then pressure-sensitive adhesives made of acrylate are usually used. They can be adjusted even better to the specific requirements because acrylate consists of synthetic polymers that can be "tailored."