Molds for the manufacture of ophthalmic devices

Abstract

The method includes subjecting the ophthalmic device mold-forming material to drying conditions in a first inert gas environment for a period of time sufficient to substantially dry the ophthalmic device mold-forming material, forming a first ophthalmic device mold part and a second ophthalmic device mold part from the substantially dried ophthalmic device mold-forming material, and subjecting the first ophthalmic device mold part and the second ophthalmic device mold part to a second inert gas environment for a period of time sufficient to substantially remove all oxygen in the first ophthalmic device mold part and the second ophthalmic device mold part.

Description

[Technical field]

[0001] Claiming priority This application claims priority to U.S. Provisional Patent Application No. 63 / 157,130, entitled “Molds for Production of Ophthalmic Devices,” filed March 5, 2021, the contents of which are incorporated by reference herein in their entirety. [Background technology]

[0002] Contact lenses have been manufactured by various methods, including lathing and cast molding. Lathing cannot meet the demands of high volume and high speed production. Efforts to reduce the cost disadvantages inherent in lathing have produced processes that are hybrids of lathing and cast molding. For example, a lens may be prepared by cast molding one side of the lens and lathing the other side. This process is less expensive than lathing, but not as cheap as a full cast molding process.

[0003] Cast molding requires the use of two complementary molds: an anterior half mold defines the anterior surface of the lens; and a posterior half mold defines the posterior surface of the lens. Half molds are traditionally used only once, after which they either serve as an element of the finished lens packaging or are discarded. To produce contact lens half molds of a desired radius or output, a batch of baseline molds is manufactured using posterior and anterior step tools. The baseline mold must be measured for accuracy and then a series of step modifications must be made until the desired dimensions are achieved in the resulting half mold. The desired final lens product dictates the design of the required posterior and anterior half molds.

[0004] For example, contact lenses are commonly molded by depositing a hardenable liquid into a mold cavity defined by two half molds. These molds are often disposable, and the cost of replacing the mold for each new lens is a significant portion of the total cost of the final lens. The liquid is then cured within the mold cavity. Following the curing process, the cured lens is removed from the mold cavity. The lens then typically moves through other post-curing steps to produce the finished lens. Summary of the Invention

[0005] According to an exemplary embodiment, a method includes: (a) subjecting an ophthalmic device mold-forming material to drying conditions in a first inert gas environment for a period of time sufficient to substantially dry the ophthalmic device mold-forming material; (b) forming a first ophthalmic device mold part and a second ophthalmic device mold part from the dried ophthalmic device mold-forming material; and (c) subjecting the first ophthalmic device mold part and the second ophthalmic device mold part to a second inert gas environment for a period of time sufficient to substantially remove all oxygen in the first ophthalmic device mold part and the second ophthalmic device mold part.

[0006] According to another exemplary embodiment, a system includes at least one processing device including a processor coupled to a memory configured to perform the steps of: (a) subjecting the ophthalmic device mold-forming material to drying conditions in a first inert gas environment for a period of time sufficient to substantially dry the ophthalmic device mold-forming material, (b) forming a first ophthalmic device mold part and a second ophthalmic device mold part from the dried ophthalmic device mold-forming material, and (c) subjecting the first ophthalmic device mold part and the second ophthalmic device mold part to a second inert gas environment for a period of time sufficient to substantially remove all oxygen in the first ophthalmic device mold part and the second ophthalmic device mold part.

[0007] According to yet another exemplary embodiment, an article of manufacture includes a processor-readable storage medium having executable code encoded therein for one or more software programs, which when executed by one or more processing devices perform the steps of: (a) subjecting the ophthalmic device mold-forming material to drying conditions in a first inert gas environment for a period of time sufficient to substantially dry the ophthalmic device mold-forming material; (b) molding a first ophthalmic device mold part and a second ophthalmic device mold part from the dried ophthalmic device mold-forming material; and (c) subjecting the first ophthalmic device mold part and the second ophthalmic device mold part to a second inert gas environment for a period of time sufficient to substantially remove all oxygen in the first ophthalmic device mold part and the second ophthalmic device mold part. [Brief description of the drawings]

[0008] Exemplary embodiments of the invention are described in more detail below with reference to the accompanying drawings.

[0009] [Figure 1] FIG. 2 is a schematic exploded view of an exemplary mold assembly according to an exemplary embodiment. [Diagram 2] 2 is a schematic cross-sectional view of the mold assembly of FIG. 1 assembled for casting a contact lens according to an exemplary embodiment. [Diagram 3] FIG. 1 illustrates a flow diagram of a process for making a mold assembly in accordance with one or more exemplary embodiments. [Figure 4] 1 illustrates an example of a processing platform that may be utilized in a system to perform method steps in an exemplary embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Exemplary embodiments are described herein with reference to exemplary methods and systems for creating molds for the manufacture of ophthalmic devices such as soft contact lenses, however, it should be understood that the embodiments described herein are not limited to use with the specific exemplary methods and systems shown.

[0011] In the process of preparing large volume ophthalmic devices, the presence of oxygen at normal atmospheric conditions may cause inhibition of the reactive monomer mixture on the surface of the ophthalmic device, and therefore incomplete and non-homogeneous curing. This, in turn, may adversely alter the physical properties of the ophthalmic device, such as, for example, the captive bubble contact angle. The presence of oxygen typically requires that the mold used to make the ophthalmic device be degassed for at least about 8 to about 12 hours prior to casting and curing the monomer mixture. This degassing time is necessary to remove absorbed and adsorbed oxygen on the mold surface. Without this degassing time, the resulting ophthalmic device may have poor surface properties, such as contact angle, which may additionally impede the release of the ophthalmic device from the mold.

[0012] The methods and systems described herein advantageously reduce degassing times from about 8 hours to about 12 hours to about 30 minutes to about 2 hours. This is accomplished, for example, by subjecting the ophthalmic device mold-forming material to drying conditions in an inert gas environment for at least a period of time sufficient to substantially dry the ophthalmic device mold-forming material prior to degassing the mold parts. Thus, the resulting ophthalmic device formed from this method can achieve a similar lens low contact angle (CBCA) in significantly less time than an ophthalmic device produced under a conventional process in which the mold parts are degassed for about 8 to about 12 hours.

[0013] Exemplary embodiments will now be discussed in more detail with respect to mold assemblies for the manufacture of ophthalmic devices. As used herein, the terms "ophthalmic device" and "lens" refer to devices that reside in or on the eye. These devices can provide optical correction, wound care, drug delivery, diagnostic functions, cosmetic enhancement, or any combination of these properties. Representative examples of such devices include, but are not limited to, soft contact lenses, such as hydrogel soft lenses, non-hydrogel soft lenses, intraocular lenses, overlay lenses, intraocular inserts, optical inserts, protective lenses, and therapeutic lenses. As will be understood by those skilled in the art, a lens is considered "soft" if it can fold back on itself without breaking. Ophthalmic devices, such as the high water content contact lenses of the exemplary embodiments, may be spherical, toric, bifocal, and may contain cosmetic tints, opaque cosmetic patterns, combinations thereof, and the like.

[0014] In an exemplary embodiment, the mold assembly described herein includes at least a pair of matable mold parts. A representative example of a mold assembly for use herein is generally shown in Figures 1 and 2 as mold assembly 25. In particular, mold assembly 25 includes a rear mold 30 having a rear mold cavity-defining surface 31 (forming the rear surface of the molded lens) and a front mold 40 having a front mold cavity-defining surface 41 (forming the front surface of the molded lens). When the mold sections are assembled, a mold cavity 32 is formed between the two defining surfaces that correspond to the desired shape of the contact lens to be molded therein. As seen in Figures 1 and 2, front mold 40 includes a surface 42 opposite front mold cavity-defining surface 41 and surfaces 41 and 42 that define a segment 43 between front mold 40. The facing surface 42 of the front mold 40 does not contact the polymerizable lens mixture when casting a contact lens, ie, the facing surface 42 does not form part of the mold cavity 32 .

[0015] An exemplary embodiment of a method and system for making a mold assembly will now be described with reference to the flow diagram of Figure 3. Specifically, Figure 3 illustrates a method 300 in which step 310 involves subjecting the ophthalmic device mold forming material to drying conditions in an inert gas environment for a period of time sufficient to substantially dry the ophthalmic device mold forming material. Drying the ophthalmic device mold forming material may include, for example, supercritical drying, subcritical drying, thermal drying, evaporative air drying, vacuum drying, or any combination thereof. In one exemplary embodiment, the ophthalmic device mold forming material is vacuum dried.

[0016] In an exemplary embodiment, the ophthalmic device mold forming material can be dried, for example, by vacuum drying, at a pressure ranging from about 10 mmHg to about 125 mmHg for a period ranging from about 0.25 hours to about 8 hours. In another exemplary embodiment, the ophthalmic device mold forming material is vacuum dried at a pressure ranging from about 15 mmHg to about 50 mmHg for a period ranging from about 0.5 hours to about 2 hours. Drying can be performed in an inert gas environment, such as a nitrogen gas environment. Typically, the dried ophthalmic device mold forming material is maintained in the inert gas environment until the step of forming the first and second ophthalmic device mold parts described below.

[0017] In one exemplary embodiment, the ophthalmic device mold forming material may be heated before or during drying to a temperature of at least about 60° C. In one exemplary embodiment, the ophthalmic device mold forming material may be heated to a temperature of from about 60° C. to about 100° C.

[0018] Ophthalmic device molding materials are generally made from plastic materials that provide certain physical characteristics to the lenses. Suitable plastic materials include, for example, thermoplastics, which generally have relatively high oxygen permeability. In an exemplary embodiment, the ophthalmic device molding materials include, for example, polymers and copolymers that contain primarily polyolefins. Suitable polyolefins include, for example, polyethylene, polypropylene, polystyrene, and the like, and mixtures thereof. In an exemplary embodiment, the plastic molding material is polypropylene.

[0019] In another exemplary embodiment, the ophthalmic device mold forming material comprises, for example, a cyclic block copolymer. Suitable cyclic block copolymers include, for example, styrene-based cyclic block copolymers, such as styrene-conjugated diene cyclic block copolymers and fully hydrogenated styrene-conjugated diene block copolymers. In one embodiment, the cyclic block copolymer can be a non-hydrogenated or fully hydrogenated styrene-butadiene copolymer, as shown below. [ka]

[0020] Styrene-butadiene copolymers can be made by methods known in the art or commercially available, for example, as ViviOn™ 8210 cyclic block copolymer from USI Corporation, Kaohsiung City, Taiwan. Cyclic block copolymers such as the non-hydrogenated or hydrogenated styrene-butadiene copolymers described above can have a weight average molecular weight ranging from about 100,000 to about 900,000 daltons.

[0021] The ophthalmic device forming material may be in the form of, for example, a material film, melt pellets, hot melt, etc. Each form is described below.

[0022] Film-Material Films can be prepared by two methods: (i) film extrusion or (ii) compression molding. In film extrusion, material pellets of the ophthalmic device-forming material are fed into an extruder, where the molten material is forced through a slit die and cooled into a film. In compression molding, material pellets of the ophthalmic device-forming material are melted at a temperature of about 100°C to about 150°C in a single or twin screw extruder, or a co-rotating or counter-rotating heated kneader (e.g., Banbury or Brabender mixer). In this process, the melt is extruded onto a plate, then capped with a second plate, and pressed in a heated Carver press at about 135°C and 7000 psi for approximately 10 minutes to produce a film thickness of about 200 to about 1000 microns. A relatively small portion of this film, for example, approximately 10x10 mm, is then placed onto the bottom cavity of the molding machine. The top cavity is then aligned and pressed down onto the film forming the lens.

[0023] Melt Pellets - Melt pellets can be prepared by melting material pellets of ophthalmic device forming material in a single screw extruder, then forcing them through an orifice that is approximately 25% smaller than the desired diameter of the melt pellets. As the material is extruded from the orifice, a die face knife is used to cut the molten ball of material. In this way, melt pellets are produced and can be sent to a mold cavity for subsequent compression molding into lenses.

[0024] Hot Melt - In this process, pellets of material are melted in an extruder or heated cylinder and then forced through an orifice approximately 0.1-2 mm in diameter (preferably 0.5-1 mm in diameter) using either a piston or compressed air, creating small molten beads that are either dropped or sprayed directly into the mold cavity and then compression molded into lenses.

[0025] Figure 3 further illustrates method 300, where step 320 involves molding a first ophthalmic device mold part and a second ophthalmic device mold part (i.e., a posterior mold part and a front mold part) from the dried ophthalmic device molding material of step 310 to form a mold assembly as described above with respect to Figures 1 and 2. In an exemplary embodiment, the first ophthalmic device mold part and the second ophthalmic device mold part (i.e., a front mold part and a rear mold part) are injection molded from the dried ophthalmic device molding material in any suitable injection molding apparatus known in the art.

[0026] FIG. 3 further illustrates method 300, where step 330 involves subjecting the first and second ophthalmic device mold parts produced in step 320 to an inert gas environment for a period of time sufficient to substantially remove all oxygen in the first and second ophthalmic device mold parts. In an exemplary embodiment, the first and second ophthalmic device mold parts are degassed in a nitrogen gas environment. The period for degassing the first and second ophthalmic device mold parts may range from about 2 hours to about 8 hours. In one embodiment, the period for degassing the first and second ophthalmic device mold parts may range from about 2 hours to about 4 hours. After exposing the first and second ophthalmic device mold parts to an inert gas environment, such as nitrogen, the oxygen levels at their surfaces are within acceptable limits, typically essentially zero within equipment capabilities, e.g., less than about 1% by weight, or less than about 0.5% by weight, or less than about 0.01% by weight oxygen content.

[0027] The mold assembly described herein is particularly useful for improving the surface quality of contact lenses produced, for example, by a cast molding process using free radical polymerization techniques. In general, monomer mixtures, molding processes, and polymerization processes for forming contact lenses are well known, and the present invention is primarily directed to forming a mold assembly for achieving contact lenses with improved surface properties. In addition, the mold assembly resulting from the exemplary embodiment described herein can also be used to improve surface quality with any free radical polymerization process that uses the mold parts made herein to provide a predetermined shape to the final polymerization product.

[0028] The mold assembly described herein can be used to manufacture any ophthalmic device, and the monomer mixture and the particular monomers used to form the ophthalmic device are not critical. In one embodiment, the mold assembly described herein is used to manufacture soft contact lenses, such as those commonly referred to as hydrogel lenses (e.g., silicone hydrogel lenses), prepared from silicone and / or non-silicone monomers, including, but not limited to, hydroxyethyl methacrylate, N-vinyl-pyrrolidone, glycerol methacrylate, methacrylic acid, and acid esters. However, any combination of lens-forming monomers in the monomer mixture that can form a polymer useful for making contact lenses may be used. Hydrophobic lens-forming monomers may also include those that contain silicone moieties, and the like. It is believed that the degree of polymerization and / or crosslink density at the surface of the lens is improved in all contact lenses, even those that typically do not exhibit cosmetic defects.

[0029] In one embodiment, the ophthalmic devices provided herein include devices formed from materials that are not themselves hydrophilic. Such devices are formed from materials known in the art, including, for example, polysiloxanes, perfluoropolyethers, fluorinated poly(meth)acrylates or equivalent fluorinated polymers derived, for example, from other polymerizable carboxylic acids, polyalkyl(meth)acrylates or equivalent alkyl ester polymers derived, for example, from other polymerizable carboxylic acids, or fluorinated polyolefins, for example, fluorinated ethylene propylene polymers, or tetrafluoroethylene, preferably in combination with a dioxole, for example, perfluoro-2,2-dimethyl-1,3-dioxole. Representative examples of suitable bulk materials include, but are not limited to, Lotrafilcon A, Neofocon, Pasifocon, Telefocon, Fluosilfocon, Paflufocon, Silafocon, Elastofilcon, Fluorofocon, or Teflon™ AF materials such as Teflon™ AF 1600 or Teflon™ AF 2400, which are copolymers of about 63 to about 73 mol % perfluoro-2,2-dimethyl-1,3-dioxole and about 37 to about 27 mol % tetrafluoroethylene, or about 80 to about 90 mol % perfluoro-2,2-dimethyl-1,3-dioxole and about 20 to about 10 mol % tetrafluoroethylene.

[0030] In another embodiment, the ophthalmic devices provided herein include devices formed from materials that are themselves hydrophilic because reactive groups, such as, for example, carboxy, carbamoyl, sulfate, sulfonate, phosphate, amine, ammonium or hydroxyl groups, are inherently present in the material and therefore present on the surface of the ophthalmic device produced therefrom. Such devices are formed from materials known in the art, including, for example, polyhydroxyethyl acrylate, polyhydroxyethyl methacrylate (HEMA), polyvinylpyrrolidone (PVP), polyacrylic acid, polymethacrylic acid, polyacrylamide, polydimethylacrylamide (DMA), polyvinyl alcohol, and the like, and copolymers thereof, such as copolymers of two or more monomers selected from hydroxyethyl acrylate, hydroxyethyl methacrylate, N-vinylpyrrolidone, acrylic acid, methacrylic acid, acrylamide, dimethylacrylamide, vinyl alcohol, and the like. Representative examples of suitable bulk materials include, but are not limited to, Polymacon, Tefilcon, Methafilcon, Deltafilcon, Bufilcon, Phemfilcon, Ocufilcon, Focofilcon, Etafilcon, Hefilcon, Vifilcon, Tetrafilcon, Perfilcon, Droxifilcon, Dimefilcon, Isofilcon, Mafilcon, Nelfilcon, Atlafilcon, and the like. Examples of other suitable bulk materials include samfilcon A, balafilcon A, hilafilcon A, alphafilcon A, bilafilcon B, and the like.

[0031] In another embodiment, the ophthalmic devices provided herein include devices formed from a material that is an amphiphilic segmented copolymer containing at least one hydrophobic segment and at least one hydrophilic segment linked together via bonds or crosslinking members.

[0032] It is particularly useful to use the biocompatible materials herein, including both soft and hard materials commonly used in ophthalmic lenses, including contact lenses. In general, non-hydrogel materials are hydrophobic polymeric materials that do not contain water in their equilibrium state. Exemplary non-hydrogel materials include silicone acrylics, such as those formed from bulky silicone monomers (e.g., tris(trimethylsiloxy)silylpropyl methacrylate, commonly known as "TRIS" monomers), poly(dimethylsiloxane) prepolymers end-capped with methacrylate, or silicones with fluoroalkyl side groups (polysiloxanes are also commonly known as silicone polymers).

[0033] In general, hydrogels are a well-known class of materials that contain hydrated crosslinked polymer systems that contain water in equilibrium. Thus, hydrogels are copolymers prepared from hydrophilic monomers. In the case of silicone hydrogels, hydrogel copolymers are generally prepared by polymerizing a mixture containing at least one device-forming silicone-containing monomer and at least one device-forming hydrophilic monomer. Either the silicone-containing monomer or the hydrophilic monomer can function as a crosslinker (a crosslinker defined as a monomer having multiple polymerizable functional groups), or a separate crosslinker may be used. Silicone hydrogels typically have a water content of about 10 to about 80 percent by weight.

[0034] Representative examples of useful hydrophilic monomers include, but are not limited to, amides such as N,N-dimethylacrylamide and N,N-dimethylmethacrylamide, cyclic lactams such as N-vinyl-2-pyrrolidone, and (meth)acrylated poly(alkene glycols), such as poly(diethylene glycol) of various chain lengths containing monomethacrylate or dimethacrylate end caps. Still further examples are the hydrophilic vinyl carbonate monomers or hydrophilic vinyl carbamate monomers disclosed in U.S. Pat. No. 5,070,215, and the hydrophilic oxazolone monomers disclosed in U.S. Pat. No. 4,910,277, the disclosure of which is incorporated herein by reference. Other suitable hydrophilic monomers will be apparent to those skilled in the art. For example, 2-hydroxyethyl methacrylate (HEMA) is a well-known hydrophilic monomer that can be used in admixture with the aforementioned hydrophilic monomers.

[0035] The monomer mixture may also include a second device-forming monomer that includes a copolymerizable group and a reactive functional group. The copolymerizable group is preferably an ethylenically unsaturated group, so that this device-forming monomer copolymerizes with the hydrophilic device-forming monomer and any other device-forming monomers in the initial device-forming monomer mixture. In addition, the second monomer may include a reactive functional group that reacts with a complementary reactive group of the copolymer that is the reaction product of one or more polymerizable polyhydric alcohols and one or more polymerizable fluorine-containing monomers. In other words, after the device is formed by copolymerizing the device-forming monomer mixture, the reactive functional group provided by the second device-forming monomer remains to react with the complementary reactive moiety of the copolymer.

[0036] In one embodiment, the reactive group of the second device-forming monomer comprises an epoxide group. Thus, the second device-forming monomer comprises both an ethylenically unsaturated group (allowing the monomer to copolymerize with the hydrophilic device-forming monomer) and an epoxide group (not reacting with the hydrophilic device-forming monomer but remaining reactive with the copolymer, which is the reaction product of one or more polymerizable polyhydric alcohols and one or more polymerizable fluorine-containing monomers). Examples include glycidyl methacrylate, glycidyl acrylate, glycidyl vinyl carbonate, glycidyl vinyl carbamate, 4-vinyl-1-cyclohexene-1,2-epoxide, etc.

[0037] As mentioned above, one type of ophthalmic device substrate material is silicone hydrogel.In this case, initial device forming monomer mixture further comprises silicone-containing monomer.Applicable silicone-containing monomer material for forming silicone hydrogel is well known in the art, and many examples are provided in U.S. Patent No. 4,136,250, U.S. Patent No. 4,153,641, U.S. Patent No. 4,740,533, U.S. Patent No. 5,034,461, U.S. Patent No. 5,070,215, U.S. Patent No. 5,260,000, U.S. Patent No. 5,310,779 and U.S. Patent No. 5,358,995. Specific examples of suitable materials for use herein include those disclosed in U.S. Pat. Nos. 5,310,779, 5,387,662, 5,449,729, 5,512,205, 5,610,252, 5,616,757, 5,708,094, 5,710,302, 5,714,557, and 5,908,906, the contents of which are incorporated herein by reference.

[0038] Representative examples of applicable silicone-containing monomers include bulky polysiloxanylalkyl(meth)acrylic monomers. One example of a bulky polysiloxanylalkyl(meth)acrylic monomer is represented by the structure of Formula I: [ka] In the formula, X represents -O- or -NR-, R represents hydrogen or C1-C4 alkyl, and each R 1 each R 2 each independently represents a lower alkyl group, a phenyl group, or a group represented by the following formula: [ka] In the formula, each R 2’ each independently represents a lower alkyl or phenyl group, and h is 1 to 10.

[0039] Examples of bulky monomers include methacryloxypropyl tris(trimethyl-siloxy)silane or tris(trimethylsiloxy)silylpropyl methacrylate (sometimes called TRIS), and tris(trimethylsiloxy)silylpropyl vinylcarbamate (sometimes called TRIS-VC).

[0040] Such bulky monomers may be copolymerized with silicone macromonomers, which are poly(organosiloxanes) capped with unsaturated groups at two or more ends of the molecule. U.S. Patent No. 4,153,641 discloses a variety of unsaturated groups, such as acryloxy or methacryloxy groups.

[0041] Another class of representative silicone-containing monomers includes, for example, silicone-containing vinyl carbonate or vinyl carbamate monomers such as 1,3-bis[4-vinyloxycarbonyloxy)but-1-yl]tetramethyl-disiloxane; 3-(trimethylsilyl)propyl vinyl carbonate; 3-(vinyloxycarbonylthio)propyl-[tris(trimethylsiloxy)silane]; 3-[tris(trimethylsiloxy)silyl]propyl vinyl carbamate; 3-[tris(trimethylsiloxy)silyl]propyl allyl carbamate; 3-[tris(trimethylsiloxy)silyl]propyl vinyl carbonate; t-butyldimethylsiloxyethyl vinyl carbonate; trimethylsilylethyl vinyl carbonate; trimethylsilylmethyl vinyl carbonate, and the like, and mixtures thereof.

[0042] Another type of silicone-containing monomer includes polyurethane-polysiloxane macromonomers (sometimes called prepolymers), which may have hard-soft-hard blocks like traditional urethane elastomers. These may be endcapped with hydrophilic monomers such as HEMA. Examples of such silicone urethanes are disclosed in various publications, including Lai, Yu-Chin, "The Role of Bulky Polysiloxanylalkyl Methacryates in Polyurethane-Polysiloxane Hydrogels," Journal of Applied Polymer Science, Vol. 60, 1193-1199 (1996). PCT Published Application No. WO 96 / 31792 discloses examples of such monomers, the disclosure of which is incorporated herein by reference in its entirety. Further examples of silicone urethane monomers include those represented by formulae II and III: E(*D*A*D*G) a *D*A*D*E', or (II) E(*D*G*D*A) a *D*A*D*E', or (III) In the formula: D independently represents an alkyl diradical, an alkylcycloalkyl diradical, a cycloalkyl diradical, an aryl diradical, or an alkylaryl diradical having 6 to about 30 carbon atoms; G independently represents an alkyl diradical, a cycloalkyl diradical, an alkylcycloalkyl diradical, an aryl diradical, or an alkylaryl diradical having from 1 to about 40 carbon atoms, which may contain ether, thio, or amine linkages in the backbone; * represents a urethane or ureido bond, a is at least 1, A independently represents a divalent polymerizable radical of formula IV: [ka] In the formula, each R s independently represent an alkyl or fluoro-substituted alkyl group having 1 to about 10 carbon atoms which may contain ether linkages between the carbon atoms; m' is at least 1; and p is a number providing a site weight of from about 400 to about 10,000; Each of E and E′ independently represents a polymerizable unsaturated organic radical represented by formula V: [ka] In the formula, R 3 is hydrogen or methyl; R 4 is hydrogen, an alkyl group having 1 to 6 carbon atoms, or -CO-YR 6 group, Y is -O-, -S-, or -NH-; R 5 is a divalent alkylene radical having 1 to about 10 carbon atoms, R 6 is an alkyl radical having 1 to about 12 carbon atoms, X represents -CO- or -OCO-; Z represents -O- or -NH-; Ar represents an aromatic radical having from about 6 to about 30 carbon atoms; w is an integer of 0 to 6, x is 0 or 1, y is 0 or 1, and z is 0 or 1.

[0043] In one embodiment, the silicone-containing urethane monomer is represented by formula VI: [ka] In the formula, m is at least 1, preferably 3 or 4, a is at least 1, preferably 1, p is a number providing a site weight of about 400 to about 10,000, preferably at least about 30, and R 7 is the diradical of a diisocyanate after removal of an isocyanate group, such as the diradical of isophorone diisocyanate, and each E″ is a group represented by: [ka]

[0044] In another embodiment, the silicone hydrogel material comprises (in bulk, i.e., in the copolymerized monomer mixture) about 5 to about 50 weight percent, or about 10 to about 25 weight percent, of one or more silicone macromonomers, about 5 to about 75 weight percent, or about 30 to about 60 weight percent, of one or more polysiloxanylalkyl(meth)acrylic monomers, and about 10 to about 50 weight percent, or about 20 to about 40 weight percent, of a hydrophilic monomer. Generally, silicone macromonomers are poly(organosiloxanes) capped with unsaturated groups at two or more ends of the molecule. In addition to the end groups in the above structural formula, U.S. Pat. No. 4,153,641 discloses additional unsaturated groups, including acryloxy or methacryloxy. Fumarate-containing materials, such as those disclosed in U.S. Pat. Nos. 5,310,779, 5,449,729, and 5,512,205, are also useful substrates according to embodiments described herein. The silane macromonomer may be a silicone-containing vinyl carbonate or vinyl carbamate, or a polyurethane-polysiloxane having one or more hard-soft-hard blocks and endcapped with a hydrophilic monomer.

[0045] Another type of representative silicone-containing monomer comprises fluorinated monomer.Such monomer has been used in the formation of fluorosilicone hydrogels to reduce the accumulation of deposits on contact lenses made therefrom, as disclosed in, for example, U.S. Patent No. 4,954,587, U.S. Patent No. 5,010,141 and U.S. Patent No. 5,079,319.Also, it has been found that the use of silicone-containing monomers with certain fluorinated side groups, i.e., -(CF2)-H, improves the compatibility between hydrophilic monomer units and silicone-containing monomer units.See, for example, U.S. Patent No. 5,321,108 and U.S. Patent No. 5,387,662.

[0046] The silicone materials described above are merely exemplary, and other materials may be used that are disclosed in various publications and are continually being developed for use in manufacturing ophthalmic devices, such as contact lenses and other medical devices. For example, the ophthalmic devices may be formed from at least cationic monomers, such as cationic silicone-containing monomers or cationic fluorinated silicone-containing monomers.

[0047] The monomer mixture used in forming the resulting ophthalmic device with the mold assembly described herein may also include crosslinkers, toughening agents, free radical initiators and / or catalysts, etc., as are known in the art. Additionally, suitable solvents or diluents may be used in the monomer mixture, provided such solvents or diluents do not adversely affect or interfere with the polymerization process.

[0048] The method of polymerization or curing is not critical to the practice of the present invention. Thus, polymerization can occur by various mechanisms depending on the specific composition used. For example, free radical polymerization techniques heat, light, X-ray, microwave, and combinations thereof can be used herein. In one exemplary embodiment, thermal polymerization and photopolymerization are used. In another exemplary embodiment, photocuring is used.

[0049] Generally, molded lenses are formed by depositing a hardenable liquid, such as a polymerizable monomer and / or macromer, into a mold cavity of a mold section of a mold assembly as described herein, hardening the liquid to a solid state, opening the mold cavity, and removing the lens. Other processing steps, such as hydrating the lens, can then be performed. Cast molding techniques are also well known. Examples of cast molding processes are disclosed in U.S. Patent Nos. 4,113,224, 4,121,896, 4,208,364, and 4,208,365, the contents of which are incorporated herein by reference. Of course, many other cast molding teachings are available that can be used herein.

[0050] The resulting ophthalmic device obtained herein may then be packaged immediately after the manufacture of the ophthalmic device, before being sent to the customer / wearer, by immersing the ophthalmic device in an aqueous packaging solution. Alternatively, the packaging and storage in the packaging solution may occur at an intermediate point after the manufacture and transportation of the ophthalmic device in a dry state, but before being sent to the final customer (wearer), and the dry ophthalmic device is hydrated by immersing the ophthalmic device in the packaging solution. Thus, the packaging for sending to the customer may include a sealed container containing one or more unused ophthalmic devices immersed in the aqueous packaging solution.

[0051] As is apparent from the above, the methods described herein may be executed on a system for performing the steps of the method for producing the mold assembly and the resulting ophthalmic device. Generally, the system may include at least one or more of the processing modules or other components of the system, each of which may be executed on a computer, server, storage device, or other processing platform element. Any such element may be considered an example of what is more generally referred to herein as a "processing device." One example of a processing platform is the processing platform 400 shown in FIG. 4.

[0052] In this embodiment, the processing platform 400 comprises a portion of a system and includes multiple processing devices, designated 402-1, 402-2, 402-3, . . . 402-K, that communicate with each other via a network 404.

[0053] The network 404 may include any type of network, including, by way of example, a global computer network such as the Internet, a WAN, a LAN, a satellite network, a telephone or cable network, a cellular network, a wireless network such as a WiFi or WiMAX network, or various portions or combinations of these and other types of networks.

[0054] The processing device 402 - 1 in the processing platform 400 includes a processor 410 coupled to a memory 412 .

[0055] The processor 410 may include a microprocessor, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a central processing unit (CPU), a graphics processing unit (GPU), a tensor processing unit (TPU), a video processing unit (VPU), or other types of processing circuitry, as well as portions or combinations of such circuit elements.

[0056] Memory 412 may include random access memory (RAM), read only memory (ROM), flash memory, or other types of memory in any combination. Memory 412 and other memories disclosed herein should be viewed as illustrative examples of what is more commonly referred to as a "processor-readable storage medium" that stores executable program code for one or more software programs.

[0057] An article of manufacture comprising such a processor-readable storage medium is considered an exemplary embodiment. A given such article of manufacture may include, for example, a storage array, a storage disk, or an integrated circuit containing RAM, ROM, flash memory, or other electronic memory, or any of a wide variety of other types of computer program products. As used herein, the term "article of manufacture" is understood to exclude transitory propagating signals. Many other types of computer program products comprising a processor-readable storage medium may be used.

[0058] The processing device 402-1 also includes network interface circuitry 414, which is used to interface the processing device with the network 404 and other system components, and may include a conventional transceiver.

[0059] The other processing devices 402 of the processing platform 400 are assumed to be configured in a similar manner as shown for processing device 402-1 in the figure.

[0060] Again, the particular processing platform 400 shown in the figure is presented merely as an example, and the system may include additional or alternative processing platforms, as well as multiple individual processing platforms in any combination, each such platform comprising one or more computers, servers, storage devices, or other processing devices.

[0061] It should therefore be understood that in other embodiments, different arrangements of additional or alternative elements may be used, where at least a subset of these elements may be collectively implemented on a common processing platform, or where each such element may be implemented on a separate processing platform.

[0062] As indicated above, the components of the systems disclosed herein for performing the steps of the methods for making the mold assemblies and resulting ophthalmic devices may be embodied, at least in part, in the form of one or more software programs stored in memory and executed by a processor of a processing device. For example, at least a portion of the functionality for manufacturing the mold assemblies and resulting ophthalmic devices as disclosed herein is illustratively embodied in the form of software running on one or more processing devices.

[0063] The following examples are provided to enable one skilled in the art to practice the invention and are merely illustrative of the invention. The examples should not be construed as limiting the scope of the invention as defined in the claims. The following abbreviations are used in the examples:

[0064] Contact Angle (CBCA): Captive bubble contact angle data was collected on a First Ten Angstroms FTA-1000 drop Shape Instrument. All samples were rinsed in HPLC grade water prior to analysis to remove components of the packaging solution from the sample surface. Prior to data collection, the surface tension of the water used for all experiments was measured using the pendant drop method. Surface tension values ​​of 70-72 dynes / cm were expected for the water to be deemed suitable for use. All lens samples were placed on a curved sample holder and submerged in a quartz cell filled with HPLC grade water. Advancing and receding captive bubble contact angles were collected for each specimen. The advancing contact angle is defined as the angle measured in water as the bubble is receding from the lens surface (water is advancing across the surface). All captive bubble data was collected using a high speed digital camera focused on the sample / bubble interface. Contact angles were calculated in digital frames just prior to the contact line movement across the sample / bubble interface. The receding contact angle is defined as the angle measured in water when an air bubble is swelling across the sample surface (the water is receding from the surface).

[0065] Examples 1 to 4 The polypropylene pellets were fed into a vacuum dryer consisting of three separate chambers. The polypropylene pellets were placed in the first chamber and air heated to 82°C was passed through the chamber for 30 minutes to heat the resin. The polypropylene pellets were then automatically transferred to the second chamber where a vacuum was applied at 25 mmHg for 30 minutes to remove any moisture present from the polypropylene pellets. After the vacuum time was completed, the dried pellets were transferred to a holding hopper chamber where the pellets were held under nitrogen. The pellets were then transferred via a tube containing nitrogen to a hopper on an injection molding machine. The hopper was also under nitrogen. The pellets were then injection molded between the optical and non-optical tools in the mold base to form the front and back molds. The front and back mold parts were then placed in a chamber with an oxygen reducing environment and exposed to nitrogen for periods of 2, 4, 6, and 8 hours (ODE hours), respectively.

[0066] The degassed front and rear mold pieces were removed from the chamber. A Samfilcon A silicone hydrogel contact lens forming monomer mixture was then cast into a contact lens by introducing the monomer mixture into the degassed front and rear mold piece assembly. The mold assembly and monomer mixture were light cured to form a contact lens. The resulting contact lens was released from the mold assembly and contact angles (CBCA) were measured as shown below in Table 1.

[0067] Comparative Examples 1 and 2 Mold assemblies and contact lenses were prepared as described for Examples 1-4 above, except that the mold assembly of Comparative Example 1 was not vacuum dried and the mold assembly of Comparative Example 2 was placed in a reduced oxygen environment chamber and exposed to nitrogen for a minimum period of less than 15 minutes. [Table 1]

[0068] As can be seen, the resulting contact lenses prepared using the mold assemblies of Examples 1-4 had comparable and significantly improved contact angles compared to the resulting contact lenses prepared using the mold assemblies of Comparative Examples 1 and 2.

[0069] Examples 5 and 6 The polypropylene pellets were placed in the first chamber and air heated to 82°C was passed through the chamber for 30 minutes to heat the resin. The polypropylene pellets were then automatically transferred to the second chamber where a vacuum was applied at 25 mmHg for 30 minutes and 60 minutes, respectively, to remove any moisture present from the polypropylene pellets. After the vacuum time was completed, the dried pellets were transferred to a holding hopper chamber where the pellets were held under nitrogen. The pellets were then transferred via a tube containing nitrogen to a hopper on an injection molding machine. The hopper was also under nitrogen. The pellets were then injection molded between the optical and non-optical tools in the mold base to form the front and back molds. The front and back mold parts were then placed in a chamber with an oxygen reducing environment and exposed to nitrogen for periods of 2 hours and 1.25 hours, respectively (ODE hours).

[0070] The degassed front and rear mold pieces were removed from the chamber. A Samfilcon A silicone hydrogel contact lens forming monomer mixture was then cast into a contact lens by introducing the monomer mixture into the degassed front and rear mold piece assembly. The mold assembly and monomer mixture were light cured to form a contact lens. The resulting contact lens was released from the mold assembly and contact angles (CBCA) were measured as shown below in Table 2.

[0071] Comparative Example 3 Mold assemblies and contact lenses were prepared as described for Examples 5 and 6 above, except that the mold assembly of Comparative Example 3 was not vacuum dried but was placed in a chamber with a reduced oxygen environment and exposed to nitrogen for 16 hours. [Table 2]

[0072] As can be seen, the resulting contact lenses prepared using the mold assemblies of Examples 5 and 6 had comparable contact angles compared to the resulting contact lenses prepared using the mold assembly of Comparative Example 3. In addition, comparing Example 5 and Example 6, it can be seen that the ODE time can be reduced by approximately 45 minutes by increasing the vacuum drying time from 30 minutes to 1 hour.

[0073] Examples 7 to 10 The polypropylene pellets were fed into a vacuum dryer consisting of three separate chambers. The polypropylene pellets were placed in the first chamber and air heated to 82°C was passed through the chamber for 30 minutes to heat the resin. The polypropylene pellets were then automatically transferred to the second chamber where a vacuum was applied at 25 mmHg for 30 minutes to remove any moisture present from the polypropylene pellets. After the vacuum time was completed, the dried pellets were transferred to a holding hopper chamber where the pellets were held under nitrogen. The pellets were then transferred via a tube containing nitrogen to a hopper on an injection molding machine. The hopper was also under nitrogen. The pellets were then injection molded between the optical and non-optical tools in the mold base to form the front and back molds. The front and back mold parts were then exposed to air for 15, 30, 45, and 60 minutes, respectively. For each example, the front and back mold parts were then placed in a chamber with an oxygen reducing environment and exposed to nitrogen for a period of 2 hours (ODE time).

[0074] The degassed front and rear mold pieces were removed from the chamber. A Samfilcon A silicone hydrogel contact lens forming monomer mixture was then cast into a contact lens by introducing the monomer mixture into the degassed front and rear mold piece assembly. The mold assembly and monomer mixture were light cured to form a contact lens. The resulting contact lens was released from the mold assembly and contact angles (CBCA) were measured as shown below in Table 3.

[0075] Comparative Example 4 Mold assemblies and contact lenses were prepared as described for Examples 7-10, except that the mold assembly of Comparative Example 1 was not vacuum dried. [Table 3]

[0076] As can be seen, the resulting contact lenses prepared using the mold assemblies of Examples 7-10 had comparable and significantly improved contact angles compared to the resulting contact lenses prepared using the mold assembly of Comparative Example 4.

[0077] Example 11 Pellets obtained from ViviOn™ 8210 cyclic block copolymer (USI Corporation) were fed into a vacuum dryer consisting of three separate chambers. The pellets were placed in the first chamber and air heated to 82° C. was passed through the chamber for 30 minutes to heat the resin. The pellets were then automatically transferred to the second chamber where a vacuum was applied at 25 mmHg for 30 minutes to remove any moisture present from the pellets. After the vacuum time was completed, the dried pellets were transferred to a holding hopper chamber where the pellets were held under nitrogen. The pellets were then transferred to a hopper on an injection molding machine via a tube containing nitrogen. The hopper was also under nitrogen. The pellets were then injection molded between the optical and non-optical tools in the mold base to form the front and back molds. The front and back mold parts were then placed in a chamber with an oxygen reducing environment and exposed to nitrogen for a period of 2 hours (ODE time).

[0078] The degassed front and rear mold pieces were removed from the chamber. A Samfilcon A silicone hydrogel contact lens forming monomer mixture was then cast into a contact lens by introducing the monomer mixture into the degassed front and rear mold piece assembly. The mold assembly and monomer mixture were light cured to form a contact lens. The resulting contact lens was released from the mold assembly and contact angles (CBCA) were measured as shown below in Table 4. [Table 4]

[0079] As can be seen, the resulting contact lenses prepared using the mold assembly of Example 11 had comparable contact angles compared to the resulting contact lenses prepared using the mold assembly described above obtained from polypropylene pellets.

[0080] For the sake of brevity, various features disclosed herein are described in the context of a single embodiment, but may also be provided separately or in any suitable subcombination.All combinations of the embodiments are specifically encompassed by the exemplary embodiments disclosed herein, as if each and every combination were individually and expressly disclosed herein.In addition, all subcombinations listed in the embodiments that describe such variables are also specifically encompassed by the formulation, and are disclosed herein, as if each and every such subcombination were individually and expressly disclosed herein.

[0081] It should be emphasized again that the above-described embodiments are presented for illustrative purposes only. Many variations and other alternative embodiments may be used. For example, the disclosed technology is applicable to a wide variety of other types of information processing systems, storage systems, models, metrics, extinction curves, events that affect performance, and the like. Also, the specific structure of the system and device elements and related processing operations exemplarily shown in the drawings may be changed in other embodiments. Furthermore, the various assumptions made above in the course of describing the exemplary embodiments should also be considered as illustrative, rather than as requirements or limitations of the present disclosure. Numerous other alternative embodiments within the scope of the appended claims will be readily apparent to those skilled in the art.

Claims

1. 1. A method comprising: (a) subjecting an ophthalmic device mold forming material to drying conditions in a first inert gas environment for a period of time sufficient to substantially dry the ophthalmic device mold forming material; (b) forming a first ophthalmic device mold part and a second ophthalmic device mold part from the dried ophthalmic device mold material; (c) subjecting the first ophthalmic device mold part and the second ophthalmic device mold part to a second inert gas environment for a period of time sufficient to substantially remove all oxygen in the first ophthalmic device mold part and the second ophthalmic device mold part.

2. Subjecting an ophthalmic device mold forming material to drying conditions in a first inert gas environment for a period of time sufficient to substantially dry the ophthalmic device mold forming material, 10. The method of claim 1, comprising drying the ophthalmic device mold material by vacuum drying for a period ranging from 0.25 hours to 8 hours at a pressure ranging from 10 mmHg to 125 mmHg.

3. Subjecting an ophthalmic device mold forming material to drying conditions in a first inert gas environment for a period of time sufficient to substantially dry the ophthalmic device mold forming material, Drying the ophthalmic device mold material by vacuum drying for a period of 30 minutes to 2 hours at a pressure ranging from 15 mmHg to 50 mmHg. The method of claim 1 , comprising:

4. A method according to any one of claims 1 to 3, wherein the first inert gas environment is a nitrogen gas environment.

5. The method of any one of claims 1 to 4, wherein the dried ophthalmic device mold forming material is maintained in the first inert gas environment until step (b) of forming the first and second ophthalmic device mold parts.

6. The method of any one of claims 1 to 5, further comprising heating the ophthalmic device mold forming material to a temperature of 60°C to 100°C prior to subjecting the ophthalmic device mold forming material to drying conditions in a first inert gas environment for a period of time sufficient to substantially dry the ophthalmic device mold forming material.

7. 7. The method of claim 1, wherein forming the first ophthalmic device mold part and the second ophthalmic device mold part from the dried ophthalmic device mold forming material comprises injection molding the dried ophthalmic device mold forming material.

8. The method of any one of claims 1 to 7, wherein the ophthalmic device molding material is one of a polyolefin or a cyclic block copolymer.

9. The method of any one of claims 1 to 8, wherein subjecting the first ophthalmic device mold part and the second ophthalmic device mold part to a second inert gas environment for a period of time sufficient to substantially remove all oxygen in the first ophthalmic device mold part and the second ophthalmic device mold part comprises exposing the first ophthalmic device mold part and the second ophthalmic device mold part to a nitrogen gas environment for a period of time in the range of 2 hours to 8 hours, and wherein the first ophthalmic device mold part and the second ophthalmic device mold part have an oxygen content of less than 1 weight%, or less than 0.5 weight%, or less than 0.01 weight%.

10. 1. A system comprising: at least one processing device comprising a processor coupled to a memory; the at least one processing device: (a) subjecting an ophthalmic device molding material to drying conditions in a first inert gas environment for a period of time sufficient to substantially dry the ophthalmic device molding material; (b) forming a first ophthalmic device mold part and a second ophthalmic device mold part from the dried ophthalmic device mold material; (c) subjecting the first ophthalmic device mold part and the second ophthalmic device mold part to a second inert gas environment for a period of time sufficient to substantially remove all oxygen in the first ophthalmic device mold part and the second ophthalmic device mold part.

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