US Patent 7253422 Container having irradiated indicia

A method of making an identifiable container by providing a molded plastic container that includes at least one layer of material blended with an additive. A mask is provided having a radiation aperture in the form of identifiable indicia, and radiation is directed through the aperture of the mask and onto the container such that the radiation is absorbed by the additive, thereby causing the additive to visibly respond in the form of the identifiable indicia.