Лако-красочные материалы — производство

The property first noted about PSAs is their tack. We know what tack feels like, but how do we describe it and, for that matter, how do we generate materials with tack? The addition of certain low-molecular-weight materials to elastomers in a process called ‘tackification’ generates tack, although due to their low molecular weight these tackifiers decrease the cohesive strength of the elastomer. It is important, however, that a PSA has both tack and sufficient cohesive strength to hold two surfaces together. Indeed, this represents the major challenge when formulating PSAs, namely to generate a balance of properties so that PSAs combine these seemingly mutually exclusive properties to produce a material with sufficient ability to not only hold onto the adherent but also be cleanly removed from the adherent and have adequate shear strength. A combination of high-molecular-weight polymers with low Tgs and low-molecular-weight resins or plasticizer oils can generate the required balance of properties.

Tackifiers form a unique class of materials in that they normally have a low molecular weight and are resinous, while their glass transition and softening temperatures are often much above room temperature. It is this combination that makes the materials useful in the formulation of PSAs. Tackifying resins are usually based on natural products or components obtained from crude petroleum.