This invention is a process for the manufacture of water stable, partially polymerized antimicrobial silanol quaternary ammonium compounds (SQACs) and their trisilanol, polysiloxanol and water soluble polysiloxane derivatives thereof. Partial polymerization is accomplished by allowing the aqueous SQAC product solution to polymerize at conditions that will substantially convert all the chlorosilanol monomer to a copolymer of the SQAC, thus reducing the toxicity of the solution greatly. A stabilizing agent is added either before or after the partial polymerization. The stabilizing agent is selected from a list of antimicrobial, naturally occurring, renewable phytochemical essential oils and extracts that easily form crystal clear microemulsions when water is added to the concentrated SQAC/essential oil mixture. These non-foaming oil in water microemulsions have excellent long term storage stability, are freeze/thaw stable, remain very low in viscosity and do not phase separate or precipitate for many months. Many of the essential oils found to be useful in this process are non-toxic food additives and have pleasant scents, have low flammability yet are volatile enough to evaporate upon cure down of the SQAC, thereby resulting in a higher concentration of SQAC in the cured, antimicrobial film. Economically shippable concentrations of the low toxicity, partially polymerized, stabilized SQACs can be further diluted with water to application concentrations without losing any of their stabilizing properties and remain storage stable at these lower concentrations indefinitely. In particular, the invention relates to the use of such aqueous dilutions cured as durable antimicrobial coatings on both manufactured and natural substrates and for human or animal skin that covalently bond to the skin, remain active through many washings and reduce or eliminate bacteria, viruses and fungi for days.
