The viscoelasticity of plastics manifests itself under long-term load through a constant decrease in material stiffness. This leads to creep at constant tension, i.e. h. to increasing deformation, under constant deformation to decrease stress (relaxation). Relaxation can be viewed as a type of creep in which the tension is controlled so that the deformation always remains the same. - The tendency of plastics to creep varies greatly depending on the primary structure and morphology of the polymers and the additives.

Depending on the composition of an adhesive, the creep resistance, i.e. the resistance to deformation over a longer period of time, can be increased in relation to external mechanical forces.