Plastisols

Plastisols are single-component adhesives that are applied as a paste to the substrate. The paste consists of solid polyvinylchloride (PVC) particles dispersed in plasticizer. In order to form a bond, the applied adhesive is heated so that the thermoplastic PVC swells and can take up the plasticizer. The two-phase system (sol) converts to a single-phase system (gel) by incorporating the plasticizer in the swollen polymer. This process occurs at a temperature between 300 and 360°F (150 and 180°C) and results in an adhesive film consisting of a plasticized polymer.

Plastisols have high flexibility and good peel resistance. They do; however, have the disadvantage that they are sensitive to shear stress and they also tend to undergo creep when subjected to loads. For most applications, as an adhesive sealant this has no adverse effects. Being thermoplastics, they only have limited resistance to heat. If overheated, for example during spot welding, there is also the risk of liberating hydrochloric acid. A typical area of application for plastisols is in vehicle body construction. Besides their bonding function, they also serve to seal joints against moisture, to dampen vibrations and to increase the rigidity of the body.  Plastisols can also be used to bond non-pretreated metal sheets as they have the ability to take up oil. On the down side, PVC plastisols give rise to environmental problems (PVC issue) when recycling the bonded components, and consequently have become increasingly replaced by alternative adhesives, such as epoxy resins.