EA Microspheres


Xerox has developed a new technology for the preparation of microspheres called the Emulsion Aggregation Process. This process originated from the investigation of new methods of preparing toner from smaller elements. Xerox is now offering its technology for biotech, personal care, and other related applications.

Technology Description

Emulsion Aggregation (EA) is a process of growing 1-15 micron size particles from smaller, nanometer size constituents. The process is environmentally advantaged in that it is water based and does not use organic solvents commonly required to make particles in this size range.

The process begins with the preparation of polymer particles in the nanometer size range emulsified in water. These particles and other desired components are then brought together in an aqueous based environment. Through control of the required chemical and physical conditions, the constituent particles are aggregated together to form larger particles. Once the particles reach their target size, the growth mechanism is halted and the particles are heated to achieve the desired shape. Particles can be completely spherical or somewhat irregular in shape.

Since the mechanism of particle formation is one of controlled growth, rather than mechanical breakage, there is effective control of the particle size distribution and excellent geometric standard deviations are achieved.

The nature of the polymers utilized allows functional groups to be present on the surface of the resulting microsphere for potential ligand attachment or chemical modification. The process permits magnetite, colorants, and other materials to be readily incorporated within the microspheres. The Emulsion Aggregation Process also enables the ability to create layered structures. Adding resin after the inital particle formation can produce a shell to cover any surface additives.

Within Xerox, the Emulsion Aggregation Process is currently being used to prepare toner particles on a large scale. Small particle size and narrow particle size distribution have demonstrated significant advantages for electrophotographic applications.

Intellectual Property Summary

Xerox Intellectual Property includes patents, patent applications, and know-how.

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