Method for marking a water-absorptive contact lens: dyeing dry lens with a mark using reduced vat dye and then making the dye insoluble
AssigneesMenicon Co., Ltd., Tomei Sangyo Kabushiki Kaisha
InventorsKoji Onda, Toshihisa Sakai, Yasuhiro Yokoyama, Takanori Shibata, Yasuyuki Kato
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Abstract
A method for tinting a water-absorptive contact lens to have a mark tinted thereon, which comprises superimposing on a water-absorptive contact lens in the dry state a screen provided with a tinting pattern corresponding to the mark to be tinted on the contact lens, applying to the contact lens through the tinting pattern of the screen a dye solution containing a vat dye and an alkaline reducing agent, followed by insolubilizing the vat dye.
Claims7
A method for marking a water-absorptive contact lens to have a mark tinted thereon, which comprises superimposing on a water-absorptive contact lens in the dry state a screen provided with a tinting pattern corresponding to the mark to be tinted on the contact lens, applying to the contact lens through the tinting pattern of the screen a dye solution containing a vat dye and an alkaline reducing agent, followed by insolubilizing the vat dye.
Dependencies are inferred from the claim text.