METHOD OF PRODUCING CLOSURES OF A THERMOPLASTIC MATERIAL HAVING THE APPEARANCE OF NATURAL CORK

摘要

A method for making closures resembling natural cork for selaing liquid product containers is described. A strand of expandable plastic material is injected into each mold cavity and is permitted to collect in that cavity in randomly oriented groups of coils which expand to fill the cavity and coalesce to create randomly oriented grain lines on the surface of the closure resembling the appearance of natural cork. Also described are methods of molding the closures which preclude the formation of leakage channels on the closure surface and preferred blends of plastic resins and pigment particles used to achieve the cork-like appearance.