Patent ID: 6863851

Claim:
A process for making flakes comprising: providing a vacuum deposition chamber containing a deposition surface; providing a release coat source and a flake deposition source in the vacuum deposition chamber, each directed toward the deposition surface; depositing on the deposition surface under vacuum in alternating layers a vaporized polymeric release coat layer from the release coat source and a vapor deposited layer of flake material from the flake deposition source to build up in sequence a multi-layer vapor deposit of flake material layers separated by and deposited on corresponding intervening release coat layers; the release coat layers comprising a polymeric material which was vaporized under vacuum to form a smooth continuous solvent soluble and dissolvable barrier layer and support surface on which each of the layers of flake material is formed; in which the polymeric release coat material has been melted outside the vacuum chamber and delivered to the chamber where the release coat source comprises a heating device which vaporizes the release coat material and in which the vaporized release coat material is conveyed to the deposition surface and deposited thereon as said release coat layer; in which the flake deposition source comprises a thermal source in the vacuum chamber for evaporating the flake material; and removing the multi-layer vapor deposit from the vacuum deposition chamber and separating it into flakes by treatment with a solvent which dissolves the release coat layers and yields flakes with smooth, flat surfaces which are essentially free of the release coat material.