| abstract |
This invention is a continuous or batchwise process and apparatus for the manufacture of microcapsules having a core which contains a liquid, gaseous, solid or multiple-phase material which is coated with an impermeable film. The microcapsules are formed by applying high pressure, for a short period of time, to a mixture of the core and shell material, and by gradually reducing the pressure, such as by passing the capsules through a baffled chamber. The invention also includes a method for adjusting the size of the microcapsules and the thickness of their shells. The microcapsules can be made with several shell layers, to increase their strength, or as multiple capsules, having two or more cores. The apparatus comprises premixing block (33), compression chamber (34), pressure reduction block (36), optional recycle line (37), and optional capsule hardening block (38). The invention is especially useful in producing time-release capsules and produces micro-capsules in a small fraction of the time required by prior art methods. |