Multi-layered resin coated sand

Abstract

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.

Dependencies are inferred from the claim text.