Encapsulation process

Encapsulation of active ingredients and active substances for permanent sealing and controlled release

The Fraunhofer Institute for Silicate Research ISC has installed a patent-backed encapsulation platform based on UV-curing shell systems.

The encapsulation of liquids, i.e., the portioning and surrounding of the drops with a suitable shell, is a fine art. Behind every encapsulated product is a great deal of individual development work. Aqueous solutions, suspensions and emulsions in particular have always posed a major challenge. As a solution, a robust multi-purpose encapsulation instrument was developed that can be operated according to the plug-and-produce principle with a library of different shell materials and can be adapted to new encapsulation tasks with little changeover effort.

The process is based on vibration-induced droplet generation using concentric nozzles. It preferably addresses the area of so-called “microcapsules” in the size range of 0.3-5 mm. The hardening of the capsules takes place in free fall at high radiation intensity and shortest exposure time (typically 5/100 seconds), which results in low stress on the contents on the one hand and maximum hardening of the shell materials on the other. Conversion rates of well over 90% reduce the residual monomer content to the level of the detection limit and thus ensure a new product quality.

A library of different shell systems is available ready for use, borrowed from the paint, varnish and toner industry, which are pre-classified into the categories multipurpose, barrier and release. In particular, there is a stock of so-called ethoxylated shell systems with built-in weak points in the form of polyethylene glycol units, which can be used for the controlled release of active ingredients through swelling, osmotic disruption or pH-induced degradation. Water vapor and aroma barrier materials are also available and are constantly being improved.