Insulating core material having coated insulated spheres and a process for making the insulating core material

An insulating core material for a refrigerating appliance, the insulating core material comprising:

• a plurality of insulating glass spheres, wherein a plurality of interstitial spaces are defined between at least a portion of the insulating glass spheres of the plurality of insulating glass spheres;
• a coating material applied at least to an outer surface of each insulating glass sphere of the plurality of insulating glass spheres, wherein the coating material includes ground particles of glass spheres that are adhered to the plurality of insulating glass spheres, wherein the coating material modifies the outer surface to define a retaining outer surface of each insulating glass sphere of the plurality of insulating glass spheres;
• and
• a secondary insulating material combined with the plurality of insulating glass spheres, wherein the secondary insulating material is at least partially retained by the retaining outer surfaces of the plurality of insulating glass spheres to occupy the plurality of interstitial spaces.