US 11,886,045 B2
Method for making photochromic contact lenses
Yuan Chang, Atlanta, GA (US); Junhao Ge, Redwood City, CA (US); Steve Yun Zhang, Sugar Hill, GA (US); Michelle Plavnik, Atlanta, GA (US); and Augustine Twum Kumi, Grayson, GA (US)
Assigned to Alcon Inc., Fribourg (CH)
Filed by Alcon Inc., Fribourg (CH)
Filed on Nov. 3, 2021, as Appl. No. 17/518,423.
Claims priority of provisional application 63/109,537, filed on Nov. 4, 2020.
Prior Publication US 2022/0137433 A1, May 5, 2022
Int. Cl. G02C 7/04 (2006.01); B29D 11/00 (2006.01); C08J 7/18 (2006.01); G02B 1/04 (2006.01); G02C 7/10 (2006.01)
CPC G02C 7/049 (2013.01) [B29D 11/00048 (2013.01); C08J 7/18 (2013.01); G02B 1/043 (2013.01); G02C 7/102 (2013.01); C08J 2300/00 (2013.01); C08J 2451/00 (2013.01)] 16 Claims
 
1. A method for producing photochromic contact lenses, comprising the steps of:
(1) obtaining a first polymerizable fluid composition, wherein the first polymerizable fluid composition is free of any polymerizable or non-polymerizable photochromic compound and comprises (i) at least one polymerizable material, (ii) at least one first free-radical initiator, and (iii) at least one iniferter;
(2) introducing the first polymerizable fluid composition into a lens mold, wherein the lens mold comprises a male mold half having a first molding surface and a female mold half having a second molding surface, wherein the male and female mold halves are configured to receive each other such that a mold cavity is formed between the first and second molding surfaces and the first polymerizable fluid composition is enclosed in the mold cavity when the mold is closed;
(3) curing thermally or actinically the first polymerizable fluid composition in the mold cavity of the lens mold to form an unprocessed contact lens having a crosslinked polymer network with iniferter moieties covalently attached thereto;
(4) separating the lens mold into the male and female mold halves, with the unprocessed contact lens adhered onto a lens-adhered mold half which is one of the male and female mold halves;
(5) applying a second polymerizable fluid composition onto a central circular region on the surface of the unprocessed contact lens adhered on the lens-adhered mold half, wherein the second polymerizable fluid composition comprises (iv) at least one photochromic vinylic monomer and (v) at least one second free-radical initiator; and
(6) after the second polymerizable fluid composition has penetrated and diffused into the crosslinked polymer network, initiating iniferter-induced polymerization of the second polymerizable composition to graft said at least one photochromic vinylic monomer onto the crosslinked polymer network, thereby obtaining an unprocessed photochromic contact lens having a central photochromic zone that has a diameter of about 13 mm or less and is concentric with the central axis of the unprocessed photochromic contact lens and capable of undergoing reversible change from a colorless or light-colored state to a colored state upon exposure to UV/HEVL radiation.