Molds for making contact lenses
View Patent ↗The present invention general related to a reusable mold for making a contact lens comprises a first mold half having a first mold surface in contact with a polymerizable and/or crosslinkable silicone containing lens forming composition and a second mold half having a second mold surface in contact with the lens-forming composition, and the first mold half and the second mold half are configured to receive each other such that a cavity is formed between the first mold surface and the second mold surface. The cavity defines the shape of a contact lens to be molded. The reusable mold has at least one of the mold halves being made from an oxide glass comprising fluorine and/or fluoride. The mold made by oxide glass comprising fluorine and/or fluoride demonstrates improving mold cleanability with water based cleaning process.
1. A method for producing a contact lens, comprising: the steps of:
(1) providing a contact lens mold, wherein the mold comprising a first mold half having a first mold and a second mold half having a second mold surface, wherein the first mold half and the second mold half are configured to receive each other such that a cavity is formed between the first mold surface and the second mold surface, wherein the cavity defines the shape of a contact lens to be molded, wherein at least one of the mold halves is made from an oxide glass comprising fluorine and/or fluoride,
(2) introducing a silicone-containing lens-forming material into the cavity formed by the first and second molding surfaces, wherein the lens-forming composition is crosslinkable and/or polymerizable by actinic radiation;
(3) crosslinking/polymerizing the lens-forming material in the mold to form a lens having a polymer matrix;
(4) opening the mold and removing the formed contact lens from the mold,
(5) washing the first and second molding surface with a water base cleaning system, wherein the molding surface of step (5) is characterized by having a percentage of reduction in the lens forming material residue on the molding surface by at least 30% when one of the mold halves is made from an oxide glass comprising fluorine and/or fluoride relative to the mold surface when one of the mold halves is made from an oxide glass comprising no fluorine and/or fluoride.
2. The method of claim 1 , wherein the silicone-containing lens forming material comprises at least one components selected from the group consisting of a silicone-containing vinylic monomer, a silicone-containing vinylic macromer, a silicone-containing prepolymer, a hydrophilic vinylic monomer, a hydrophobic vinylic monomer, a crosslinking agent, a free-radical initiator, a hydrophilic vinylic macromer/prepolymer, and combinations thereof.
3. The method of claim 1 , wherein the actinic radiation is a UV radiation.
4. The method of claim 1 , wherein the oxide glass further comprises oxide glass selected from the group consisting of potassium oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, boron oxide, aluminum oxide, silicon oxide, phosphorous oxide, and a combination thereof.
5. The method of claim 4 , wherein the oxide glass further comprises oxide glass selected from the group consisting of phosphorous oxide, silicon oxide and a combination thereof.
6. The method of claim 5 , wherein the oxide glass further comprises 1%-30% phosphorous oxide.
7. The method of claim 1 , wherein the molding surface of step (5) is characterized by having a percentage of reduction in the lens forming material residue on the molding surface by at least 50% when one of the mold halves is made from an oxide glass comprising fluorine and/or fluoride relative to the mold surface when one of the mold halves is made from an oxide glass comprising no fluorine and/or fluoride.
8. The method of claim 7 , wherein the molding surface of step (5) is characterized by having a percentage of reduction in the lens forming material residue on the molding surface by at least 70% when one of the mold halves is made from an oxide glass comprising fluorine and/or fluoride relative to the mold surface when one of the mold halves is made from an oxide glass comprising no fluorine and/or fluoride.
9. The method of claim 7 , wherein the molding surface of step (5) is characterized by having a percentage of reduction in the lens forming material residue on the molding surface by at least 90% when one of the mold halves is made from an oxide glass comprising fluorine and/or fluoride relative to the mold surface when one of the mold halves is made from an oxide glass comprising no fluorine and/or fluoride.