Please read the following Patents on the subject.

1. Patent US 6162836A: Process for preparing aqueous dispersion of higher fatty acid zinc salt

2. Patent US 6664018B2: In-situ method of forming zinc stearate dispersion thereof in tonners

3. Patent US 2965589A: Aqueous dispersions of zinc stearate and polyethylene glycol monoesters

thanks for your help Mr Tarafdar

An emulsion is a liquid-in-liquid scenario so you need to frame your question differently.  If you require a dispersion of ZnSt in water then a surfactant for wetting is required and stabilization either by charge (optimum concentration of phosphate here) or steric (with a polymer (PEG is mentioned above but a 50 kDa PEI has been found suitable in the past - again optimum concentration to cover the surface with a little to spare).