A method of forming a multi-layer coated particulate material, the method
including the steps of: mixing a first thermoplastic polymer with a
particulate substrate to form a mixture at a temperature greater than a
melting point of the first thermoplastic polymer; cooling the mixture to
a temperature below the melting point of the first thermoplastic polymer;
combining the cooled mixture with a second thermoplastic polymer, wherein
a melting point of the second thermoplastic polymer is less than the
temperature of the cooled mixture; and cooling the combined mixture to a
temperature less than the melting point of the second polymer. In another
aspect, embodiments disclosed herein relate to a particulate material
having: a particulate substrate coated with a first layer comprising a
first thermoplastic polymer and a second layer comprising a second
thermoplastic polymer; wherein a melting point of the first thermoplastic
polymer is greater than a melting point of the second thermoplastic
polymer.