The BRACE double-nozzle processes produce real microcapsules with a solid shell and a liquid or solid core in a single step.
The material for the inner core can be chosen independently from the shell material unless it weakens the stability of the shell. The shell material, on the other hand, can be chosen to be a solution, a molten mass or a sol or a combination of these just like with the Microspheres. The hardening of the spheres is done as described for microspheres. The result is a capsule with a solid shell and a solid (if a molten mass is used for the inner core) or a liquid core.
Materials that are encapsulated are aromes, antiallergic substances or phase change materials. Such capsules are needed e.g. by the food, the textile and the building industry.
Microcapsules are extraordinarily stable and show a great retardation for the encapsulated substances. The encapsulated substances can be released at once (e.g. if pressure is applied to the capsule or the shell material is dissolved) or little by little (which is wanted for long-term effects of antiallergic substances). Moreover, it is possible to encapsulate substances stably, like phase change materials.
If binders as hydrocolloids are used for the production of microcapsules, drying can be helpful. Because commonly used driers like heating chambers, fluidized bed driers or microwave driers are not suitable for this purpose, BRACE developed a special drum drier.