| CPC B29D 11/00067 (2013.01) [B29D 11/00057 (2013.01); B29D 11/00134 (2013.01); B29D 11/00192 (2013.01); C08G 77/20 (2013.01); C08L 83/04 (2013.01); G02B 1/043 (2013.01); G02C 7/04 (2013.01); G02C 7/102 (2013.01); G02C 7/108 (2013.01); B29K 2083/00 (2013.01); B29K 2105/0061 (2013.01); B29K 2995/0018 (2013.01); C08L 2201/10 (2013.01); C08L 2203/02 (2013.01); C08L 2312/00 (2013.01); G02B 2207/109 (2013.01)] | 21 Claims |
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1. A method for producing hydrogel contact lenses, comprising the steps of:
(1) obtain a first polymerizable fluid composition and a second polymerizable fluid composition, wherein the first polymerizable fluid composition comprises at least one photoinitiator and at least one polymerizable material and is free of any photochemically functional compound, wherein the second polymerizable fluid composition comprises said at least one photoinitiator and said at least one polymerizable material and additionally at least one photochemically functional compound, wherein the second polymerizable fluid composition is substantially identical to the first polymerizable fluid composition except that the first polymerizable fluid composition is free of said at least one photochemical functional compound present in the second polymerizable fluid composition, wherein difference in the concentration of each component of said at least one photoinitiator and said at least one polymerizable material in the first polymerizable fluid composition and in the second polymerizable fluid composition is about 2.5%, wherein said at least one photochemically functional compound is at least one photochromic compound, at least one UV/HEVL absorbing compound, at least one fluorescent compound, at least one color-filtering material for correcting color blindness, at least one diffractive material, at least one high refractive-index material, or combinations thereof, wherein the first polymerizable fluid composition has a first curing time and the second polymerizable fluid composition has a second curing time, wherein the first and second curing times are determined in photo-rheology study using a UV/visible light at a specified intensity;
(2) obtaining a lens mold, wherein the lens mold comprises a female mold half having a first molding surface defining the anterior surface of a contact lens to be molded and a male mold half having a second molding surface defining the posterior surface of the contact lens to be molded, wherein the female and male mold halves are configured to receive each other such that a mold cavity is formed between the first and second molding surfaces when the mold is closed;
(3) applying an amount of the second polymerizable fluid composition onto a central zone of the first molding surface of the female mold half to form a circular layer of the second polymerizable fluid composition, wherein the circular layer has a diameter of about 13.00 mm or less;
(4) irradiating with the UV/visible light at the specified intensity the circular layer of the second polymerizable fluid composition for a time period that is about 5% to about 75% of the second curing time, to partially crosslink the circular layer of the second polymerizable fluid composition;
(5) dispensing an amount of the first polymerizable fluid composition over the partially-crosslinked circular layer on the central zone of the first molding surface;
(6) closing the female mold half with the male mold half to form a molding assembly comprising the partially crosslinked circular layer immersed in the first polymerizable fluid composition within the mold cavity;
(7) irradiating with the UV/visible light at the specified intensity the molding assembly for a time that is at least about 120% of the first curing time to form an unprocessed hydrogel contact lens having a central zone that has a diameter of about 13 mm or less, is concentric with the central axis of the unprocessed hydrogel contact lens, and possesses at least one photochemical functionality provided by said at least one photochemically functional compound;
(8) separating the molding assembly into the male and female mold halves, with the unprocessed hydrogel contact lens adhered onto a lens-adhered mold half which is one of the male and female mold halves;
(9) removing the unprocessed hydrogel contact lens from the lens-adhered mold half; and
(10) subjecting the unprocessed hydrogel contact lens to post-molding processes including a hydration process and one or more other processes selected from the group consisting of extraction, surface treatment, packaging, sterilization, and combinations thereof.
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