Plastisol
A plastisol is a dispersion of a powdery thermoplastic polymer and possibly pigments , fillers and additives, such as blowing agents , in a liquid plasticizer .
Plastisols can be made from various polymers . However, PVC plastisols, also known as soft PVC or hot melt vinyl , are of particular importance . B. can also be used as a modeling clay (e.g. " Fimo "). Phthalic acid esters are often used as plasticizers . The mixture is selected in such a way that the polymer is soluble in the plasticizer, but the rate of dissolution at room temperature is negligible. Only at higher temperatures does the plasticizer (also called plasticizer ) diffuse into the polymer and plasticize it. When cooling, the plastisol gels , creating a mass of extremely high viscosity that is no longer flowable at room temperature. The gelation step is irreversible .
In contrast, an untempered plastisol is still in the form of a liquid paste at room temperature and can be poured, sprayed and spread. Depending on the composition, the mixture is stable on storage for weeks or months without gelling. After heating for a few minutes at typically 160 to 200 ° C, it becomes a permanently tough elastic plastic . The term plastisol is used for both the uncured mixture and the finished product.
The slow exudation of the plasticizer and release into the environment can be problematic . Many plasticizers are classified as harmful to health, e.g. B. dioctyl phthalate . In some applications - such as wallpaper or toys - higher-boiling plasticizers such as 1,2-cyclohexanedicarboxylic acid diisononyl ester (also known as Hexamoll DINCH ) are therefore used.
use
Plastisols can be found in a wide range of applications: for coating various materials such as metals e.g. B. in the automotive industry as underbody protection ; for fabric printing (screen printing) in textile coating ; for foils, tubes, wallpapers and toys. Plastisols are used in foamed form as artificial leather .
Web links
Individual evidence
- ↑ a b c d Entry on plastisols. In: Römpp Online . Georg Thieme Verlag, accessed on March 19, 2018.