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Interfacial tension of the binary systems pelargonic acid/ethane, pelargonic acid/carbon dioxide, linoleic acid/ethane, and linoleic acid/carbon dioxide was measured at 313, 333, and 353 K and pressures ranging up to 250 bar, using the capillary rise and Du Nouy ring methods. Both these methods yield similar values. The surface excess of supercritical components is deduced from the measurement results with the aid of Gibbs adsorption equation. The surface excess concentration increases with increasing gas activity, runs through a pronounced maximum, later decreasing rapidly to very small values. Near the surface excess minimum, a falling film of fatty acids disintegrates into a mist of tiny droplets

An alternative process for the manufacture of powder coatings was developed. The continuously operated process is applicable to new (low-melting and fast-reacting) and conventional powder coating systems and allows to produce coatings with improved properties. The process uses the solubility of compressed gases in melts of coating polymers at pressures up to 220 bar. The single components of a powder coating mixture are melted in separated tanks and are dosed to a static mixer by means of high-pressure pumps. In the mixer the melts are homogenized and simultaneously compressed carbon dioxide is dissolved. The so-formed solution is depressurized directly afterwards over a nozzle into a spray tower. Thereby, the melt is atomized into fine droplets and cooled by the expanding gas. The droplets reach the solidification point of the melt and fine solid particles are formed. The particle size, particle size distribution and the morphology of the powders could be adjusted by the operating parameters of the plant.