Silicon hydrogel with high elongation, contact lens and method for preparing the same

Abstract

The present application relates to a kind of high ductility silicon hydrogel, which is prepared by polymerization reaction of polymerizable composition containing thiol with functionality greater than or equal to 3, and the elongation of the high ductility silicon hydrogel is 285%-439%.The present application also relates to a kind of high ductility contact lens and its preparation method.By adding thiol with functionality greater than or equal to 3 as crosslinking agent in the formula of silicon hydrogel, the formed silicon hydrogel polymer network is more regular, more full and more stretchy, so that the prepared contact lens has good ductility, and the contact lens has high water content and low modulus.In addition, compared with the contact lens formed without adding thiol with functionality greater than or equal to 3, the size change of the contact lens formed after adding thiol with functionality greater than or equal to 3 is less than 5%.

Description

Technical Field

[0001] This application relates to the field of eyeglass materials technology, specifically to a highly ductile silicone hydrogel, a corneal contact lens, and a method for preparing the corneal contact lens. Background Technology

[0002] Contact lenses, also known as corneal contact lenses, are lenses worn on the cornea of ​​the eye to correct vision or protect the eyes. Contact lenses not only greatly improve the appearance and convenience of patients with refractive errors such as myopia, hyperopia, and astigmatism, but also provide a wide field of vision and realistic vision. Furthermore, they play a special role in controlling the progression of myopia and astigmatism in adolescents and in treating specific eye diseases. Siloxane hydrogel contact lenses, due to their high oxygen permeability and excellent comfort, are increasingly popular among users.

[0003] Hydrogel materials used in corneal contact lenses typically require a certain level of mechanical strength, such as a Young's modulus of around 0.4-0.8 MPa and an elongation of over 100%. If the modulus of the hydrogel material is too high, patients will experience discomfort and a feeling of a foreign object in their eye; if the elongation of the hydrogel material is too low, the lens will easily tear and break when rubbed with contact lens solution.

[0004] In free radical-cured contact lens formulations, bifunctional or multifunctional acrylate crosslinking agents are typically used to crosslink the polymer network to achieve the desired mechanical properties. However, the resulting crosslinked network exhibits poor regularity, and even small changes in the crosslinking dosage can lead to significant variations in the formulation's water content, modulus, and ductility. Obtaining a hydrogel material that combines high water content, high ductility, and low modulus requires extensive formulation adjustments, and the final results are often unsatisfactory.

[0005] Therefore, there is a need in this field to develop a silicone hydrogel with high water content, high ductility and low modulus, a corneal contact lens and a method for preparing the same. Summary of the Invention

[0006] The purpose of this application is to provide a highly ductile silicone hydrogel that simultaneously possesses high water content, high ductility, and low modulus. Specifically, the silicone hydrogel described herein can be prepared by a polymerizable composition through a polymerization reaction. This polymerizable composition may simultaneously contain a non-siloxane-type vinyl crosslinking agent and a thiol with a functionality greater than or equal to 3. The thiol with a functionality greater than or equal to 3 can act as a crosslinking agent and chain extender in the reaction system. By optimizing the type and content of the thiol with a functionality greater than or equal to 3, the crosslinking agent function of the thiol with a functionality greater than or equal to 3 is made dominant, thereby resulting in a corneal contact lens with high elongation and minimal dimensional change.

[0007] The purpose of this application is also to provide a corneal contact lens with high elasticity, which is made of the silicone hydrogel described above.

[0008] The purpose of this application is also to provide a method for preparing a highly elastic corneal contact lens as described above.

[0009] To address the aforementioned technical problems, this application provides the following technical solution.

[0010] In a first aspect, this application provides a highly ductile silicone hydrogel, characterized in that the highly ductile silicone hydrogel is prepared by polymerization of a polymerizable composition containing a thiol with a functionality greater than or equal to 3, and the elongation of the highly ductile silicone hydrogel is 285%-439%.

[0011] In one embodiment of the first aspect, the thiol with a functionality greater than or equal to 3 is selected from one or more of the following: trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetra-3-mercaptopropionate, and pentaerythritol tetra(3-mercaptobutyrate), preferably pentaerythritol tetra-3-mercaptopropionate or pentaerythritol tetra(3-mercaptobutyrate).

[0012] In one embodiment of the first aspect, the thiols with a functionality of 3 or greater account for 0.4% to 2% of the total weight of the polymerizable composition, based on weight. In a preferred embodiment, the thiols with a functionality of 3 or greater account for 0.48% to 1.9% of the total weight of the polymerizable composition, based on weight.

[0013] In one embodiment of the first aspect, the polymerizable composition comprises the following components: (a) a monofunctional siloxane monomer selected from one or more of vinyl-terminated polysiloxanes, acrylate-terminated polysiloxanes, and methacrylate-terminated polysiloxanes; (b) a hydrophilic N-vinylamide monomer; (c) a hydrophobic vinyl monomer; (d) a hydroxyl-containing hydrophilic vinyl monomer, wherein the hydroxyl-containing hydrophilic vinyl monomer is a hydroxyalkyl acrylate or a hydroxyalkyl methacrylate; (e) a non-siloxane type vinyl crosslinking agent; (f) a free radical initiator; and (g) a thiol with a functionality greater than or equal to 3.

[0014] In one embodiment of the first aspect, the polymerizable composition further comprises a component (h) of an ultraviolet absorber, preferably 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole.

[0015] In one embodiment of the first aspect, the monofunctional siloxane monomer is selected from one or more of the following: (meth)acrylate-terminated polydimethylsiloxanes. In one embodiment, the hydrophilic N-vinylamide monomer is selected from one or more of the following: N-methyl-N-vinylacetamide, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-ethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-3-methoxypropyl(meth)acrylamide. In one embodiment, the hydrophobic vinyl monomer is selected from one or more of the following: methyl methacrylate, cyclohexyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, styrene, methylstyrene, 4-tert-butylstyrene, 4-ethoxystyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,5-dimethylstyrene, and acrylates containing a benzene ring. In one embodiment, the hydroxyl-containing hydrophilic vinyl monomer is selected from one or more of the following: 2-hydroxypropyl methacrylate, N-2-hydroxyethyl (meth)acrylamide, N,N-bis(hydroxyethyl) (meth)acrylamide, N-3-hydroxypropyl (meth)acrylamide, N-2-hydroxypropyl (meth)acrylamide, N-2,3-dihydroxypropyl (meth)acrylamide, N-tris(hydroxymethyl)methyl (meth)acrylamide, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, glyceryl methacrylate (GMA), di(ethylene glycol) (meth)acrylate, tri(ethylene glycol) (meth)acrylate, tetra(ethylene glycol) (meth)acrylate, poly(ethylene glycol) (meth)acrylate having a number average molecular weight of up to 1500, and poly(ethylene glycol) ethyl (meth)acrylamide having a number average molecular weight of up to 1500. In one embodiment, the non-siloxane vinyl crosslinker is selected from one or more of the following: ethylene glycol dimethacrylate and triethylene glycol dimethacrylate. In one embodiment, the free radical initiator is selected from one or more of the following: peroxide, hydroperoxide, azobis(alkyl- or cycloalkylnitrile), persulfate, percarbonate, or mixtures thereof.

[0016] In one specific embodiment, the monofunctional siloxane monomer has a weight-average molecular weight of 600-1000. The benzene-ring-containing acrylate preferably includes one or more of ethyl acrylate, ethyl methacrylate, norisoborneol acrylate, and norisoborneol methacrylate. Free radical initiators include, but are not limited to: benzoyl peroxide, tert-butyl peroxide, tert-amyl peroxybenzoate, 2,2-bis(tert-butylperoxy)butane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, 2,5-bis(tert-butylperoxy)-2,5-dimethyl-3-hexyne, bis(1-(tert-butylperoxy)-1-methylethyl)benzene, 1,1-bis( tert-Butylperoxy-3,3,5-trimethylcyclohexane, di-tert-butyldiperoxyphthalate, tert-butyl hydroperoxide, tert-butyl peracetate, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, acetyl peroxide, lauroyl peroxide, decanoyl peroxide, dicetyl peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, tert-butyl peroxide Neopentyl ester, tert-butylperoxy-2-ethylhexanoate, 2,4-pentanedione peroxide, dicumyl peroxide, peracetic acid, potassium persulfate, sodium persulfate, ammonium persulfate, 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis(2-amidinylpropane) dihydrochloride, 2,2'-azobis( 2,4-Dimethylvaleronitrile), 2,2'-azobis(isobutyronitrile), 2,2'-azobis-2-methylbutyronitrile, 1,1-azobis(1-cyclohexanecarboxylonitrile); 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(methyl isobutyrate), 4,4'-azobis(4-cyanopentanoic acid), and combinations thereof, preferably, the free radical initiator is 2,2'-azobis-2-methylbutyronitrile.

[0017] In one embodiment of the first aspect, the hydrophobic vinyl monomer has a refractive index greater than 1.41 and a glass transition temperature greater than or equal to 60°C.

[0018] In a second aspect, this application provides a corneal contact lens made of a highly elastic silicone hydrogel as described in the first aspect.

[0019] In a third aspect, this application provides a method for preparing a corneal contact lens as described in the second aspect, characterized in that the method includes the following steps:

[0020] S1: A mold is provided that includes a male half mold having a raised molding surface and a female half mold having a recessed molding surface, wherein the male half mold and the female half mold are configured to receive each other, thereby forming a mold cavity between the raised molding surface and the recessed molding surface when the mold is closed.

[0021] S2: Dispense a predetermined weight of the polymerizable composition into the female half-mold;

[0022] S3: The male and female half-molds are fitted together to close the mold;

[0023] S4: The polymerizable composition located in the mold cavity is cured to form a molded corneal contact lens;

[0024] S5: The mold is separated into a male half-mold and a female half-mold, and the corneal contact lens is adhered to one of the male half-mold and the female half-mold;

[0025] S6: Squeeze the half-mold with the corneal contact lens attached to it to separate the half-mold from the corneal contact lens;

[0026] S7: Remove the corneal contact lens from the semi-mold using a vacuum suction device.

[0027] Compared with existing technologies, the advantages of this invention lie in the fact that by adding a thiol with a functionality of 3 or higher as a crosslinking agent, the resulting polymer network is more regular, fuller, and more extensible, resulting in corneal contact lenses with good extensibility, an elongation of 285%-439%, and high water content and low modulus. Furthermore, compared with corneal contact lenses formed without the addition of a thiol with a functionality of 3 or higher, the dimensional change of the corneal contact lens formed after adding a thiol with a functionality of 3 or higher is less than 5%. Attached Figure Description

[0028] Figure 1 This diagram shows a polymer network before and after stretching, formed by using a bifunctional acrylate crosslinking agent and a silicone hydrogel cured via free radical crosslinking. Figure 1 In the diagram, solid circles represent cross-linking points, and curves represent molecular chain segments.

[0029] Figure 2 This demonstrates the curing mechanism when pentaerythritol tetra-3-mercaptopropionate is used as a crosslinking agent.

[0030] Figure 3 This diagram shows a polymer network before and after stretching, formed by using pentaerythritol tetra-3-mercaptopropionate as a crosslinking agent and crosslinking the silicone hydrogel through stepwise polymerization. Figure 1 In the diagram, the cross symbol represents a cross-linking point, and the curve represents a molecular chain segment.

[0031] Figure 4This shows a schematic diagram of the side structure of the male and female semi-molds.

[0032] Figure 5 This diagram shows the male half-mold demolding device.

[0033] Figure 6 A three-dimensional view of the male half-mold demolding device is shown.

[0034] Figure 7 A three-dimensional view of the female half-mold demolding device is shown.

[0035] Figure 8 Showing a side view of the female half-mold demolding device.

[0036] Figure 9 Showing a top view of the female half-mold demolding device. Detailed Implementation

[0037] Unless otherwise stated, implied from the context, or as is customary in the art, all parts and percentages in this application are based on weight, and all testing and characterization methods used are concurrent with the filing date of this application. Where applicable, any patent, patent application, or disclosure relating to this application is incorporated herein by reference in its entirety, and its equivalent patent families are also incorporated herein by reference, particularly the definitions disclosed in these documents concerning synthetic techniques, product and processing design, polymers, comonomers, initiators, or catalysts in the art. If any definition of a specific term disclosed in the prior art is inconsistent with any definition provided in this application, the definition provided in this application shall prevail.

[0038] The numerical ranges in this application are approximate values ​​and therefore may include values ​​outside the range unless otherwise stated. A numerical range includes all values ​​from the lower limit to the upper limit, increasing by one unit, provided there is an interval of at least two units between any lower and any higher value. For example, if a component, physical, or other property (such as molecular weight, melt index, etc.) is described as 100 to 1000, this means that all individual values, such as 100, 101, 102, etc., are explicitly listed, as well as all subranges, such as 100 to 166, 155 to 170, 198 to 200, etc. For ranges containing values ​​less than 1 or fractions greater than 1 (e.g., 1.1, 1.5, etc.), one unit is appropriately considered as 0.0001, 0.001, 0.01, or 0.1. For ranges containing single digits less than 10 (e.g., 1 to 5), one unit is generally considered as 0.1. These are merely specific examples of what is intended to be expressed, and all possible combinations of values ​​between the listed minimum and maximum values ​​are considered to be clearly stated in this application. It should also be noted that the terms "first," "second," etc., used herein are not intended to specify a particular order, but are merely used to distinguish substances with different structures.

[0039] When referring to chemical compounds, unless explicitly stated otherwise, the singular includes all isomers and vice versa (e.g., "hexane" includes all isomers of hexane, individually or collectively). Additionally, unless explicitly stated otherwise, nouns described with "an," "a," or "the" also include their plural forms.

[0040] The terms “comprising,” “including,” “having,” and their derivatives do not exclude the presence of any other components, steps, or processes, regardless of whether such other components, steps, or processes are disclosed in this application. To eliminate any doubt, unless expressly stated otherwise, all compositions using the terms “comprising,” “including,” or “having” in this application may contain any additional additives, excipients, or compounds. Conversely, except for those necessary for operational performance, the term “substantially constitutes…” excludes any other components, steps, or processes described below with respect to that term. The term “consisting of…” does not include any components, steps, or processes not specifically described or listed. Unless expressly stated otherwise, the term “or” refers to the individual members listed or any combination thereof.

[0041] Terminology Definition

[0042] In this document, the term "hydrogel" refers to a polymeric material that, when fully hydrated, can absorb at least 10% by weight of water. Typically, hydrogel materials are obtained by polymerization or copolymerization of at least one hydrophilic monomer, with or without the presence of additional monomers and / or macromonomers.

[0043] In this document, the term "silicone hydrogel" refers to a hydrogel obtained by copolymerization of a polymerizable composition comprising at least one siloxane-containing monomer or at least one siloxane-containing macromolecule.

[0044] In this document, the term "monomer" refers to a low molecular weight compound with an average molecular weight of less than 700 Daltons, containing one or more polymerizable groups or one or more crosslinkable groups, and capable of being crosslinked and / or polymerized by photochemical, thermal, or chemical means to obtain crosslinked and / or polymerized polymers. The term "photochemical" as used herein in conjunction with the curing or polymerization of polymerizable compositions or materials refers to curing (e.g., crosslinking and / or polymerization) by photochemical irradiation, such as by UV irradiation, ionizing radiation (e.g., gamma-ray or X-ray irradiation), microwave irradiation, etc. Methods of thermosetting or photochemical curing are well known to those skilled in the art.

[0045] In this document, the term "macromonomer" refers to a compound or polymer of medium to high molecular weight containing functional groups capable of further polymerization / crosslinking reactions. Medium and high molecular weight generally refers to an average molecular weight greater than 700 Daltons. Preferably, the macromonomer contains olefinically unsaturated groups and can be polymerized by photochemical or thermal means.

[0046] In this document, the term "polymer" refers to a material formed by polymerizing / crosslinking one or more monomers, macromonomers and / or oligomers.

[0047] In this article, the term "mold" refers to both the male and female mold halves.

[0048] In this article, the term "semi-mold" refers to one or both of the male and female semi-molds.

[0049] In this paper, the term "elongation at break" or "elongation" refers to the ratio of the displacement of the specimen at the point of fracture to its original length.

[0050] In this paper, the term "size change" refers to the ratio of the absolute value of the difference between the diameter of a contact lens formed after adding a thiol with a functionality of 3 or higher and the diameter of a contact lens formed without adding a thiol with a functionality of 3 or higher, to the diameter of the contact lens formed without adding a thiol with a functionality of 3 or higher.

[0051] Unless otherwise stated or tested, the “molecular weight” of polymer materials (including monomeric materials or macromonomeric materials) used herein refers to number-average molecular weight.

[0052] silicone hydrogel

[0053] In a first aspect, this application provides a silicone hydrogel that can be used to prepare corneal contact lenses, the silicone hydrogel having good extensibility with an elongation of 285%-439%.

[0054] Highly ductile silicone hydrogels can be prepared by polymerization of a polymerizable composition containing a thiol with a functionality greater than or equal to 3. In one embodiment, the thiol with a functionality greater than or equal to 3 is selected from one or more of the following: trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetra-3-mercaptopropionate, and pentaerythritol tetrakis(3-mercaptobutyrate). Preferably, the thiol with a functionality greater than or equal to 3 is pentaerythritol tetra-3-mercaptopropionate or pentaerythritol tetrakis(3-mercaptobutyrate). In one embodiment, the thiol with a functionality greater than or equal to 3 comprises 0.4% to 2% of the total weight of the polymerizable composition, based on a weight ratio. In one embodiment... In this composition, based on weight, thiols with a functionality of 3 or greater account for 0.48% to 1.9% of the total weight of the polymerizable composition. For example, based on weight, thiols with a functionality of 3 or greater account for 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0% of the total weight of the polymerizable composition, or any range or subrange between any two of these values.

[0055] In a preferred embodiment, the silicone hydrogel formulation includes 0.5-2 wt% pentaerythritol tetra-3-mercaptopropionate, resulting in a thiol group ratio (defined as the sum of the molar amounts of thiol and double bonds in other crosslinking agents) of 45%-75%. After curing in a nitrogen oven, the silicone hydrogel of this type exhibits highly elastic lenses following ethanol and water extraction. In one specific embodiment, the proportion of thiol groups to the total crosslinking agent functional groups is 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, or any two of these values ​​or a subrange thereof.

[0056] Traditional silicone hydrogel formulations typically use bifunctional methacrylates (such as TEGDMA) as crosslinking agents, which crosslink with other monofunctional hydrophilic monomers VMA / HEMA and hydrophobic silicone polymers MCR-M07 to form a silicone hydrogel network. Generally, to improve the elongation of corneal contact lenses made from silicone hydrogels, it is necessary to reduce the crosslinking density of the silicone hydrogel and decrease the lens modulus. However, adjusting the elongation of the lens simply by adjusting the content of the bifunctional crosslinking agent is often difficult to achieve. For example, referring to Table 3, when using TEGDMA as a crosslinking agent, even a slight increase in the bifunctionality of the crosslinking agent (from 1.6% to 1.8%) reduces the lens elongation by approximately 60%. If the amount of crosslinking agent is further adjusted, reducing the amount of TEGDMA by half (from 1.6% to 0.8%), the elongation does increase by nearly 100%, but due to the reduced crosslinking density, the network becomes looser, resulting in an increase in water content of approximately 8%. This is disadvantageous for the practical application of contact lenses because the water content exceeds acceptable limits.

[0057] refer to Figure 1 In free radical crosslinking curing systems, the crosslinking points are randomly distributed, and the crosslinked network lacks a regular topological structure. Under uniaxial stretching, this irregular network easily collapses, resulting in low elongation and brittle, fragile lenses. Only when the crosslinking density becomes very low, the network becomes sparse, and is filled with water, does the ductility improve, but the water content exceeds acceptable limits. Therefore, using conventional crosslinking based on free radical chain growth mechanisms to formulate silicone hydrogels that achieve controllable water content, high ductility, and low modulus requires a massive amount of formulation work.

[0058] Furthermore, bifunctional or polyfunctional thiols can be used simultaneously as crosslinking agents and chain extenders in silicone hydrogel reaction systems. Referring to Table 4, based on weight, the mechanical properties of the prepared corneal contact lenses significantly deteriorated after adding more than 1% of 1,6-hexanedithiol, causing the lenses to easily shatter on the mold during demolding. This indicates that bifunctional thiols primarily act as chain transfer agents in the formulation and cannot enhance the crosslinking network.

[0059] Therefore, the innovation of this application lies in the simultaneous use of thiols with a functionality greater than or equal to 3 and non-siloxane-type vinyl crosslinking agents as crosslinking agents, and the use of a step-growth free radical polymerization mechanism of multifunctional thiols and acrylate double bonds to prepare silicone hydrogels.

[0060] Next, we will refer to Figure 2 and Figure 3 The polymerization mechanism of the polymerizable compositions described herein is described in detail using pentaerythritol tetra-3-mercaptopropionate (PETMP) as an example. Reference Figure 2 The polymerization reaction between multifunctional thiols and alkenyl monomers is also called the "thiol-ene click reaction," which includes an initiation step and a chain propagation step. In the initiation step, for example, a radical initiator such as azobisisobutyronitrile (azobisisobutyronitrile) forms an azo radical and nitrogen gas under heating conditions. The azo radical reacts with the thiol group, abstracting a hydrogen atom from the thiol group to form a thiol radical and azobisisobutyronitrile. In the chain propagation step, the thiol radical reacts with the alkenyl monomer, transferring the radical to a carbon atom of the unsaturated double bond to form an alkenyl monomer radical. The alkenyl monomer radical then reacts with the thiol group, abstracting a hydrogen atom from the thiol group to obtain a copolymer of the thiol radical and the thiol alkenyl monomer. Pentaerythritol tetra-3-mercaptopropionate has four active thiol groups; therefore, one pentaerythritol tetra-3-mercaptopropionate molecule can react with four alkenyl monomers to form a crosslinked network.

[0061] refer to Figure 3 While crosslinking occurs according to the conventional free radical mechanism, the four-arm thiol molecule PETMP and other monofunctional monomers containing acrylates undergo a stepwise free radical polymerization crosslinking reaction of thiols, resulting in a more regular, fuller, and more extensible crosslinked hydrogel network. The tetrafunctional thiol crosslinked silicone hydrogel network tends to maintain the topology of the polymer network under uniaxial stretching, thus giving the hydrogel higher ductility.

[0062] Similarly, when trifunctional thiol and nonsiloxane type vinyl crosslinking agents are used simultaneously as crosslinking agents, a more regular hydrogel network with higher elongation is obtained.

[0063] In one embodiment, the silicone hydrogel is prepared by polymerization of a polymerizable composition. The polymerizable composition comprises: (a) a monofunctional siloxane monomer; (b) a hydrophilic N-vinylamide monomer; (c) a hydrophobic vinyl monomer; (d) a hydroxyl-containing acrylic monomer, wherein the hydroxyl-containing acrylic monomer is a hydroxyalkyl acrylate or a hydroxyalkyl methacrylate; (e) a non-siloxane vinyl crosslinking agent; (f) a free radical initiator; and (g) a thiol with a functionality greater than or equal to 3. In one embodiment, the polymerizable composition further comprises: (h) a UV absorber. Preferably, the UV absorber is 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole. In a preferred embodiment, the hydrophobic vinyl monomer has a refractive index greater than 1.41 and a glass transition temperature greater than or equal to 60°C.

[0064] In one embodiment, the monofunctional siloxane monomer is selected from one or more of vinyl-terminated polysiloxanes, acrylate-terminated polysiloxanes, and methacrylate-terminated polysiloxanes. In a specific embodiment, the monofunctional siloxane monomer includes, but is not limited to, methacrylate-terminated polydimethylsiloxane. In a preferred embodiment, the weight-average molecular weight of the monofunctional siloxane monomer is 600-1000.

[0065] Monofunctional siloxane monomers are one of the main raw materials for forming silicone hydrogels. After cross-linking, monofunctional siloxane monomers can form the backbone polymer network of silicone hydrogels, resulting in soft corneal contact lenses that better fit the cornea. Furthermore, the hydroxyl groups carried by the monofunctional siloxane monomers ensure that the silicone hydrogel has good oxygen permeability.

[0066] In this application, there is no particular limitation on the weight ratio of monofunctional siloxane monomers in the polymerizable composition, as long as they can form a silicone hydrogel and provide the required mechanical and oxygen permeability. In one specific embodiment, the monofunctional siloxane monomer may account for 35%-40% of the total weight of the polymerizable composition, for example, 35%, 36%, 37%, 38%, 39%, 40%, or any two of these values ​​or sub-ranges.

[0067] Hydrophilic N-vinylamide monomers are also one of the main raw materials for forming silicone hydrogels, used to improve the water absorption rate of the resulting silicone hydrogels or corneal contact lenses. In one specific embodiment, the hydrophilic N-vinylamide monomers include, but are not limited to, the following: N-methyl-N-vinylacetamide, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-ethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and N-3-methoxypropyl(meth)acrylamide.

[0068] In this application, there is no particular limitation on the weight ratio of the hydrophilic N-vinylamide monomer in the polymerizable composition, as long as it can form a silicone hydrogel and provide the required mechanical and oxygen permeability. In one specific embodiment, the hydrophilic N-vinylamide monomer may account for 40%-50% of the total weight of the polymerizable composition, for example, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50% or any two of these values ​​or sub-ranges.

[0069] The specific combination of hydrophobic vinyl monomers and hydroxyl-containing acrylic monomers enables the corneal contact lenses of this application to have a good release rate. In a preferred embodiment, the hydrophobic vinyl monomer has a refractive index greater than 1.41 and a glass transition temperature greater than or equal to 60°C. Monomers with high glass transition temperatures (Tg) typically form harder polymers with higher mechanical strength, such as higher modulus, which facilitates release. Thus, the hydrophobic vinyl monomers provide sufficient mechanical strength for the resulting silicone hydrogel. Furthermore, the hydroxyl groups of the hydroxyl-containing acrylic monomers can form hydrogen bonds in the silicone hydrogel network, which enhances the mechanical properties of the resulting corneal contact lens and makes it tend to move away from the hydrophobic mold, thereby making the corneal contact lens easier to release.

[0070] In one specific embodiment, the hydrophobic vinyl monomer includes, but is not limited to, the following: methyl methacrylate, cyclohexyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, styrene, methylstyrene, 4-tert-butylstyrene, 4-ethoxystyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,5-dimethylstyrene, and acrylates containing a benzene ring. In a preferred embodiment, the acrylate containing a benzene ring preferably includes one or more of ethyl acrylate, ethyl methacrylate, norisoborneol acrylate, and norisoborneol methacrylate.

[0071] In one specific embodiment, the hydrophobic vinyl monomer comprises, by weight, 5% to 20% of the total weight of the polymerizable composition. For example, the hydrophobic vinyl monomer comprises 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% of the total weight of the polymerizable composition, or any range or subrange between any two of these values.

[0072] In one specific embodiment, the hydroxyl-containing acrylic monomer is hydrophilic and includes, but is not limited to, the following: 2-hydroxypropyl methacrylate, N-2-hydroxyethyl (meth)acrylamide, N,N-bis(hydroxyethyl) (meth)acrylamide, N-3-hydroxypropyl (meth)acrylamide, N-2-hydroxypropyl (meth)acrylamide, N-2,3-dihydroxypropyl (meth)acrylamide, N-tris(hydroxymethyl)methyl (meth)acrylamide, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, glyceryl methacrylate (GMA), di(ethylene glycol) (meth)acrylate, tri(ethylene glycol) (meth)acrylate, tetra(ethylene glycol) (meth)acrylate, poly(ethylene glycol) (meth)acrylate having a number average molecular weight of up to 1500, and poly(ethylene glycol) ethyl (meth)acrylamide having a number average molecular weight of up to 1500.

[0073] In one specific embodiment, the hydroxyl-containing acrylic monomer comprises 1-20% by weight of the total weight of the polymerizable composition. Preferably, the hydroxyl-containing acrylic monomer comprises 5-10% by weight of the total weight of the polymerizable composition. For example, the hydrophobic vinyl monomer comprises 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% of the total weight of the polymerizable composition, or any range or subrange between any two of these values.

[0074] In one embodiment, the non-siloxane vinyl crosslinking agent is selected from one or more of the following: ethylene glycol dimethacrylate and triethylene glycol dimethacrylate. In one embodiment, the free radical initiator is selected from one or more of the following: peroxide, hydroperoxide, azobis(alkyl- or cycloalkylnitrile), persulfate, percarbonate, or mixtures thereof. In one specific embodiment, the free radical initiator includes, but is not limited to: benzoyl peroxide, tert-butyl peroxide, tert-amyl peroxybenzoate, 2,2-bis(tert-butylperoxy)butane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, 2,5-bis(tert-butylperoxy)-2,5-dimethyl-3-hexyne, bis(1-(tert-butylperoxy)-1-methylethyl)benzene, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, di-tert-butyl disperoxyphthalate, tert-butyl hydroperoxide, tert-butyl peracetate, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, acetyl peroxide, lauroyl peroxide, decanoyl peroxide, diceryl peroxide dicarbonate, and di(4-tert-butylcyclohexyl) peroxydicarbonate (Perkadox). 16S), di(2-ethylhexyl) peroxydicarbonate, tert-butyl peroxyneopentate (Lupersol 11), tert-butyl peroxy-2-ethylhexanoate (Trigonox 21-C50), 2,4-pentanedione peroxide, dicumyl peroxide, peracetic acid, potassium persulfate, sodium persulfate, ammonium persulfate, 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile) (VAZO 33), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (VAZO 44), 2,2'-azobis(2-amidinylpropane) dihydrochloride (VAZO 50), 2,2'-azobis(2,4-dimethylpentanonitrile) (VAZO 52), 2,2'-azobis(isobutyronitrile) (VAZO 64 or AIBN), 2,2'-azobis-2-methylbutyronitrile (VAZO 67), 1,1-azobis(1-cyclohexanecarboxylonitrile) (VAZO 88); 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(methyl isobutyrate), 4,4'-azobis(4-cyanopentanoic acid), and combinations thereof. Preferably, the free radical initiator is 2,2'-azobis-2-methylbutyronitrile.

[0075] The dosage and function of non-siloxane vinyl crosslinking agents and free radical initiators are well known in the art and will not be elaborated here.

[0076] Corneal contact lenses and their preparation methods

[0077] In a second aspect, this application provides a highly elastic corneal contact lens made of a highly elastic silicone hydrogel as described above. In a third aspect, this application also provides a method for preparing a corneal contact lens.

[0078] In one specific embodiment, the method for preparing a corneal contact lens may include the following steps:

[0079] S1: A mold is provided that includes a male half mold having a raised molding surface and a female half mold having a recessed molding surface, wherein the male half mold and the female half mold are configured to receive each other, thereby forming a mold cavity between the raised molding surface and the recessed molding surface when the mold is closed.

[0080] S2: Dispense a predetermined weight of the polymerizable composition into the female half-mold;

[0081] S3: The male and female half-molds are fitted together to close the mold;

[0082] S4: The polymerizable composition located in the mold cavity is cured to form a molded corneal contact lens;

[0083] S5: The mold is separated into a male half-mold and a female half-mold, and the corneal contact lens is adhered to one of the male half-mold and the female half-mold;

[0084] S6: Squeeze the half-mold with the corneal contact lens attached to it to separate the half-mold from the corneal contact lens;

[0085] S7: Remove the corneal contact lens from the semi-mold using a vacuum suction device.

[0086] In one embodiment, the positive and negative half-molds are non-polar, and either the positive or negative half-mold can be subjected to plasma beam treatment before step S1, thereby allowing the contact lens to adhere to the plasma-treated positive or negative half-mold. For example, both the positive and negative half-molds can be made of polypropylene. In another embodiment, one of the positive and negative half-molds is polar, and the other is non-polar, with the contact lens adhering to the polar positive or negative half-mold. For example, the positive half-mold can be prepared from polybutylene terephthalate (PBT), and after the silicone hydrogel cures, the contact lens adheres to the positive half-mold. In this case, the negative half-mold can be non-polar.

[0087] refer to Figure 4 , Figure 4Showing a side view of the male half-mold 1 and the female half-mold 2. The male half-mold 1 may include a cylindrical male half-mold body 11, one end of which includes a raised molding surface 12 for molding the inner surface of the corneal contact lens facing the user's eye. The male half-mold body 11 may also include an annular flange 13 disposed on the outer periphery of the male half-mold body 11. The annular flange 13 is ejected by the male half-mold release device 10 described below (see...). Figure 5 The male mold half 1 is clamped and driven along a predetermined direction (see...). Figure 5 (Arrow direction) Rotation.

[0088] Similarly, the female mold 2 may include a cylindrical male and female mold body 21, one end of which includes a recessed molding surface 22 for molding the outer surface of the corneal contact lens on the side away from the user's eye. The female mold body 21 may also include an annular flange 23 disposed on the outer periphery of the female mold body 21. As described below, the female mold release device 20 can clamp the female mold 2 by engaging with the annular flange 23. When the male mold 1 and the female mold 2 are engaged, a mold cavity is formed between the raised molding surface 12 and the recessed molding surface 22, the shape of which is the same as the shape of the corneal contact lens to be manufactured.

[0089] Next, the method for removing corneal contact lenses will be described in detail.

[0090] In step S5, due to differences in the polymerizable composition used, the polarity of the half-mold, etc., the corneal contact lens may adhere to the positive half-mold or the negative half-mold. When they adhere to different half-molds, the subsequent demolding step S7 is also different.

[0091] In one specific embodiment, the corneal contact lens is adhered to the male half-mold 1. When the corneal contact lens is adhered to the male half-mold 1, the squeezing of the half-mold with the corneal contact lens adhered in step S7 includes squeezing the male half-mold 1 in a direction close to the male half-mold 1 along the radial direction of the male half-mold 1, so that the raised molding surface 12 of the male half-mold 1 is deformed.

[0092] Specifically, the male mold 1 can be extruded using the male mold demolding device 10. (Reference) Figure 5 and Figure 6The male mold release device 10 may include an arc-shaped outer clamping plate 101 and an arc-shaped inner clamping plate 102. The inner clamping plate 102 is a rotatable rotating disk. The gap between the outer clamping plate 101 and the arc-shaped inner clamping plate 102 gradually decreases along the rotation direction of the inner clamping plate 102. In addition, the outer clamping plate 101 may include an outer clamping plate groove 103 recessed in a direction away from the inner clamping plate 102, and the inner clamping plate 102 may include an inner clamping plate groove 104 recessed in a direction away from the outer clamping plate 101. The outer clamping plate groove 103 and the inner clamping plate groove 10 are at the same height relative to the male mold base 100. When the male mold 1 is pressed, the annular flange 13 of the male mold 1 with the corneal contact lens attached can be engaged in the corresponding outer clamping plate groove 103 and inner clamping plate groove 104. Then, the inner retaining plate 102 is driven to move relative to the outer retaining plate 101 in a direction that reduces the gap between the inner and outer retaining plates 101, thus compressing the male half-mold 1. The male half-mold 1 undergoes slight deformation after being compressed. Because the deformation of the male half-mold 1 differs from that of the corneal contact lens, the corneal contact lens separates from the male half-mold 1. In one specific embodiment, such as... Figure 5 As indicated by the arrow, the gap between the outer retaining plate 101 and the inner retaining plate 102 gradually decreases in a clockwise direction. The separated corneal contact lens can be removed from the male half-mold 1 using a vacuum nozzle.

[0093] To ensure synchronized movement between the male half-mold 1 and the corresponding inner clamping plate 102 or outer clamping plate 101, so as to facilitate rapid forward movement of the male half-mold 1 during the rotation of the inner clamping plate 102, in one embodiment, the annular outer surface of the annular flange 13 of the male half-mold 1, and the bottom of one or both of the grooves of the outer clamping plate groove 103 and the inner clamping plate groove 104 are formed with surfaces that can improve friction, such as frosted texture or grid texture. In another embodiment, the annular outer surface of the annular flange 13 of the male half-mold 1, and the bottom of one or both of the grooves of the outer clamping plate groove 103 and the inner clamping plate groove 104 are provided with corresponding teeth.

[0094] In another specific embodiment, the corneal contact lens is adhered to the negative half-mold 2. When the corneal contact lens is adhered to the negative half-mold 2, squeezing the half-mold with the corneal contact lens attached includes squeezing the negative half-mold 2 from one side toward the corneal contact lens side along the longitudinal direction of the negative half-mold 2, causing the concave molding surface 22 of the negative half-mold 2 to deform.

[0095] Specifically, it can be achieved through Figure 7-9 The female mold ejection device 20 shown is used to extrude the female mold 2. (Reference) Figure 7-9The female mold release device 20 may include a base 200 and a limiting frame 201 and a support frame 202 disposed on the base 200. The limiting frame 201 and the support frame 202 are movable relative to each other. The limiting frame 201 is substantially U-shaped, that is, the opening faces the female mold base 200, and the two side walls defining the U-shape include grooves 203 facing each other. The grooves 203 are used to hold the annular flange 23 of the female mold 2. The center of the support frame 202 includes a push rod 204 that can move up and down relative to the support frame 202 along the longitudinal direction of the support frame 202. When releasing the male mold 2 with the contact lens attached, the female mold 2 can be placed on the support frame 202 first, wherein the upper surface of the female mold 2 with the contact lens attached is away from the support frame 202, while the lower surface of the female mold 2 is supported by the support frame 202. The placement orientation of the female mold 2 can be combined with Figure 4 and Figure 8 (or Figure 7 The placement orientation of the female mold 2 and the support frame 202 is understood. Then, the limiting frame 201 is adjusted so that the annular flange of the female mold 2 engages in the groove 203 of the limiting frame 201. Finally, the push rod 204 is pushed upwards a predetermined distance at the top position of the outer surface of the female mold 2 corresponding to the concave forming surface 22, causing the female mold 2 to deform. Because the deformation of the female mold 2 is different from that of the contact lens, the contact lens separates from the female mold 2. The separated contact lens can be removed from the female mold 2 using a vacuum suction nozzle.

[0096] After washing with water and ethanol, the corneal contact lens is obtained as a hydrated corneal contact lens.

[0097] Example

[0098] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Unless otherwise specified, the reagents and raw materials used can be purchased commercially. Experimental methods in the following embodiments that do not specify specific conditions are performed according to conventional methods and conditions, or according to the product instructions.

[0099] In the following embodiments, the specific measurement process of the elongation and tensile strength of the corneal contact lens is described below.

[0100] Elongation at break, tensile strength, and Young's modulus were measured using a soft contact lens tensile strength tester (Langshan) model LPS-20CL. Specifically, the lens after hydration extraction was cut radially into curved strips 5 mm wide. The strips were fixed in the clamps of the tensile tester, with an initial sample length of 5 mm between the clamps. The tensile speed was 10 mm / min. After the strips broke, the software automatically calculated the Young's modulus, tensile strength, and elongation at break.

[0101] In the following embodiments, the specific measurement process of the EWC of the corneal contact lens is described below.

[0102] The EWC (equilibrium moisture content) measurement method is based on the gravimetric method according to the national standard GB / T 11417.7-2012.

[0103] In the following embodiments, the specific measurement process of WBUT of corneal contact lenses is described below.

[0104] WBUT (Water Breakup Time) is a simple method commonly used by contact lens developers to quickly determine the hydrophilicity of a lens surface. Specifically, clamp the edge of the lens with a small plastic clip, remove the lens from the preservation solution, and quickly shake it to remove excess water from the surface. Start timing at this point, and carefully observe the time (in seconds) it takes for the water film to recede from the edge of the clip to approximately one-quarter of the lens's diameter away from the edge. This time is the WBUT.

[0105] In the following embodiments, the specific measurement process of the oxygen permeability coefficient Dk of the corneal contact lens is described below.

[0106] The oxygen permeability coefficient was measured using polarography on a Lenser Dk-100 instrument. Specific measurement methods are detailed in section 4.3 of GB / T 11417.7-2012.

[0107] In the following embodiments, the hydration process is as follows: After the corneal contact lens is demolded, it is placed in a hydration tray and hydrated with 95% ethanol for 3.0h + 50% ethanol for 0.5h + pure water for 0.5h × 3 (i.e., the water is changed three times, once every 0.5h), during which a peristaltic pump is used for liquid circulation.

[0108] In the following embodiments, the formulations of Examples 1-3 and Comparative Examples 1-2 and the performance of the prepared corneal contact lenses are shown in Table 1.

[0109] Table 1. Formulations and performance of corneal contact lenses prepared in Examples 1-3 and Comparative Examples 1-2.

[0110]

[0111] In Table 1, PDMS-MA800 is a commercially available methacrylate-based single-terminated PDMS with a molecular weight of 600-900. VMA refers to N-methyl-N-vinylacetamide, MMA refers to methyl methacrylate, HEMA refers to 2-hydroxyethyl methacrylate, Vazo 67 refers to azobisisovalerate, Norbloc refers to 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole (CAS number 96478-09-0), TEGDMA refers to triethylene glycol dimethacrylate, and PETMP refers to pentaerythritol tetra-3-mercaptopropionate. OD refers to the outer diameter of the contact lens, EWC refers to the equilibrium water content, WBUT indicates the water film breakage time of the contact lens, used to characterize the hydrophilicity of the contact lens, Dk refers to the oxygen permeability coefficient, and n / a indicates not applicable.

[0112] Example 1

[0113] This embodiment relates to the preparation of a corneal contact lens.

[0114] The experimental steps of this embodiment are as follows.

[0115] According to the formulation shown in Table 1, 35 parts by weight of PDMS-MA-800, 45 parts by weight of VMA, 14 parts by weight of MMA, 5 parts by weight of HEMA, 0.5 parts by weight of VAZO 67, 1.8 parts by weight of Norbloc, 0.7 parts by weight of TEGDMA, and 0.5 parts by weight of PETMP were mixed to obtain the polymerizable composition according to Example 1.

[0116] The polymerizable composition according to Example 1 was poured into a mold cavity formed by a male and female mold. The mold was made of polypropylene, and the closing pressure was 5 kg. The mold was placed in a nitrogen oven, and the nitrogen flow rate was 70 L / min. First, the mold was purged at room temperature for 30 minutes. Then, according to the oven's preset program, the temperature was increased to 55°C, 80°C, and 100°C, and held at each temperature for 40 minutes to obtain the silicone hydrogel according to Example 1. In this example, 15 parallel experiments were conducted. The silicone hydrogels from 14 parallel experiments adhered to the female mold 2, and the hydrogel from 1 parallel experiment adhered to the male mold 1. The male mold 2 was demolded using the female mold demolding device 20 to obtain the dry contact lens according to Example 1.

[0117] The outer diameter, elongation, tensile strength, and Young's modulus of the corneal contact lens were measured, and the results are shown in Table 1.

[0118] In addition, the dry corneal contact lens film was hydrated to obtain hydrated corneal contact lenses, and their EWC, WBUT and Dk were measured. The results are shown in Table 1.

[0119] Example 2

[0120] This embodiment relates to the preparation of a corneal contact lens.

[0121] The experimental steps of this embodiment are as follows.

[0122] According to the formulation shown in Table 1, 35 parts by weight of PDMS-MA-800, 45 parts by weight of VMA, 14 parts by weight of MMA, 5 parts by weight of HEMA, 0.5 parts by weight of VAZO 67, 1.8 parts by weight of Norbloc, 0.7 parts by weight of TEGDMA, and 1 part by weight of PETMP were mixed to obtain the polymerizable composition according to Example 2.

[0123] The polymerizable composition according to Example 2 was poured into a mold cavity formed by a male and a female mold. The mold was made of polypropylene, and the closing pressure was 5 kg. The mold was placed in a nitrogen oven, and the nitrogen flow rate was 70 L / min. First, the oven was purged at room temperature for 30 minutes. Then, according to the oven's preset program, the temperature was increased to 55°C, 80°C, and 100°C, and held at each temperature for 40 minutes to obtain the silicone hydrogel according to Example 2. In this example, 15 parallel experiments were conducted. The silicone hydrogel adhered completely to the female mold 2. The male mold 2 was demolded using the female mold demolding device 20 to obtain the dry contact lens according to Example 2.

[0124] The outer diameter, elongation, tensile strength, and Young's modulus of the corneal contact lens were measured, and the results are shown in Table 1.

[0125] In addition, the dry corneal contact lens film was hydrated to obtain hydrated corneal contact lenses, and their EWC, WBUT and Dk were measured. The results are shown in Table 1.

[0126] Example 3

[0127] This embodiment relates to the preparation of a corneal contact lens.

[0128] The experimental steps of this embodiment are as follows.

[0129] According to the formulation shown in Table 1, 35 parts by weight of PDMS-MA-800, 45 parts by weight of VMA, 14 parts by weight of MMA, 5 parts by weight of HEMA, 0.5 parts by weight of VAZO 67, 1.8 parts by weight of Norbloc, 0.7 parts by weight of TEGDMA, and 2 parts by weight of PETMP were mixed to obtain the polymerizable composition according to Example 3.

[0130] The polymerizable composition according to Example 3 was poured into a mold cavity formed by a male and a female mold. The mold was made of polypropylene, and the closing pressure was 5 kg. The mold was placed in a nitrogen oven, and the nitrogen flow rate was 70 L / min. First, the mold was purged at room temperature for 30 minutes. Then, according to the oven's preset program, the temperature was increased to 55°C, 80°C, and 100°C, and held at each temperature for 40 minutes to obtain the silicone hydrogel according to Example 2. In this example, 15 parallel experiments were conducted. The silicone hydrogel adhered completely to the female mold 2. The male mold 2 was demolded using the female mold demolding device 20 to obtain the dry corneal contact lens according to Example 3.

[0131] The outer diameter, elongation, tensile strength, and Young's modulus of the corneal contact lens were measured, and the results are shown in Table 1.

[0132] In addition, the dry corneal contact lens film was hydrated to obtain hydrated corneal contact lenses, and their EWC, WBUT and Dk were measured. The results are shown in Table 1.

[0133] Comparative Example 1

[0134] This comparative example relates to the preparation of a corneal contact lens.

[0135] The experimental steps for this comparative example are described below.

[0136] According to the formulation shown in Table 1, 35 parts by weight of PDMS-MA-800, 45 parts by weight of VMA, 14 parts by weight of MMA, 5 parts by weight of HEMA, 0.5 parts by weight of VAZO 67, 1.8 parts by weight of Norbloc, and 0.7 parts by weight of TEGDMA were mixed to obtain the polymerizable composition according to Comparative Example 1.

[0137] The polymerizable composition according to Comparative Example 1 was poured into a mold cavity formed by a male and female half-mold. The mold was made of polypropylene, and the mold closing pressure was 5 kg. The mold was placed in a nitrogen oven, and the nitrogen flow rate was 70 L / min. First, it was purged at room temperature for 30 minutes, and then the temperature was raised to 55°C, 80°C, and 100°C respectively according to the oven preset program and held at each temperature for 40 minutes to obtain the silicone hydrogel according to Example 2. In this example, 15 parallel experiments were conducted. The silicone hydrogel adhered completely to the female half-mold 2. The male half-mold 2 was demolded using the female half-mold demolding device 20 to obtain the corneal contact lens dry film according to Comparative Example 1.

[0138] The outer diameter, elongation, tensile strength, and Young's modulus of the corneal contact lens were measured, and the results are shown in Table 1.

[0139] In addition, the dry corneal contact lens film was hydrated to obtain hydrated corneal contact lenses, and their EWC, WBUT and Dk were measured. The results are shown in Table 1.

[0140] Comparative Example 2

[0141] This comparative example relates to the preparation of a corneal contact lens.

[0142] The experimental steps for this comparative example are described below.

[0143] According to the formulation shown in Table 1, 35 parts by weight of PDMS-MA-800, 45 parts by weight of VMA, 14 parts by weight of MMA, 5 parts by weight of HEMA, 0.5 parts by weight of VAZO 67, 1.8 parts by weight of Norbloc, and 0.7 parts by weight of TEGDMA were mixed to obtain the polymerizable composition according to Comparative Example 2.

[0144] The polymerizable composition according to Comparative Example 2 was poured into a mold cavity formed by a male and female half-mold. The mold was made of polypropylene, and the closing pressure was 5 kg. The mold was placed in a nitrogen oven, and the room temperature was first purged for 30 minutes at a nitrogen flow rate of 70 L / min. Then, according to the oven's preset program, the temperature was increased to 55°C, 80°C, and 100°C respectively, and held at each temperature for 40 minutes to obtain the silicone hydrogel according to Example 2. In this comparative example, all corneal contact lenses could not be demolded.

[0145] As shown in Examples 1-3 and Comparative Examples 1-2, adding 0.5% PETMP increased the water content by nearly 4%, yet the lens size remained almost unchanged. Further increasing PETMP to 1% increased the water content by another 1%, but the lens size decreased. This is because the chain transfer effect of thiol groups on free radical polymerization reduces the polymerization conversion rate of the monomer, leading to a smaller lens size. This effect is more pronounced after adding 5% PETMP. Since the chain transfer effect exceeded the crosslinking reaction, a lens with sufficient mechanical strength was not formed, and the lens could not be removed from the mold.

[0146] In the following examples, the formulations of Examples 4-7 and Comparative Examples 3-4 and the performance of the prepared corneal contact lenses are shown in Table 2.

[0147] Table 2. Formulations and performance of corneal contact lenses prepared in Examples 4-7 and Comparative Examples 3-4.

[0148]

[0149]

[0150] In Table 2, MCR-M07 is a commercially available methacrylate-based single-terminated PDMS with a molecular weight of 600-900, TMPTP is trimethylolpropane tris(3-mercaptopropionate), and the meanings of the other terms are the same as in Table 1.

[0151] Examples 4-7

[0152] The experimental procedures in Examples 4-7 were similar to those in Example 1, except that the formulations are shown in Table 2, and in particular, the thiol was replaced with trimethylolpropane tris(3-mercaptopropionate). The performance of the prepared corneal contact lenses is shown in Table 2.

[0153] Comparative Example 3

[0154] The experimental procedure for Comparative Example 3 was similar to that for Comparative Example 1, except that the formulation is shown in Table 2. The performance of the prepared corneal contact lenses is also shown in Table 2.

[0155] Comparative Example 4

[0156] The experimental steps of Comparative Example 4 were similar to those of Example 4, but the TMPTP content was higher, and all the corneal contact lenses prepared in the end could not be demolded.

[0157] Examples 4-7 and Comparative Examples 3-4 show that the elongation of the lens increased significantly after adding a series of concentrations of the trifunctional thiol TMPTP. Considering the overall strength of the lens, an optimal TMPTP addition of approximately 1% resulted in a 60% increase in elongation. With increasing TMPTP content, the mechanical properties (modulus) of the lens further decreased. At 5% addition, the chain transfer effect of the thiol became dominant, making it impossible to form a moldable lens.

[0158] In the following examples, the formulations of Comparative Examples 5-7 and the performance of the prepared corneal contact lenses are shown in Table 3.

[0159] Table 3. Formulations and performance of the prepared corneal contact lenses in Comparative Examples 5-7

[0160] Example number Comparative Example 5 Comparative Example 6 Comparative Example 7 MCR-M07 34.3 34.3 34.3 VMA 44.1 44.1 44.1 MMA 13.7 13.7 13.7 HEMA 4.9 4.9 4.9 Vazo-67 0.5 0.5 0.5 Norbloc 1.8 1.8 1.8 TEGDMA 1.8 1.6 0.8 Total number of copies 101 100.8 100 OD(mm) 14.45 14.05 15.24 EWC 48.30％ 50.20％ 58.20％ Elongation % 81±24 135±43 244±47 Young's modulus (MPa) 0.78±0.04 0.79±0.05 0.43±0.03

[0161] In Table 3, the meanings of the terms are the same as in Table 2.

[0162] Comparative Examples 5-7

[0163] The experimental procedures for Comparative Examples 5-7 were the same as those for Example 1, but the formulations are shown in Table 3. In other words, no thiols with a functionality greater than or equal to 3 were added. The properties of the prepared corneal contact lenses are shown in Table 3.

[0164] As shown in Table 3, in formulations using only TEGDMA as a crosslinking agent, even a slight change in the crosslinking agent can cause a sudden change in the elongation of the prepared corneal contact lens, and the outer diameter of the prepared corneal contact lens can vary considerably.

[0165] In the following examples, the formulations of Comparative Examples 8-12 and the performance of the prepared corneal contact lenses are shown in Table 4.

[0166] Table 4. Formulations and performance of the prepared corneal contact lenses for Comparative Examples 8-12

[0167]

[0168]

[0169] Comparative Examples 8-12

[0170] The experimental procedures for Comparative Examples 8-12 were the same as those for Example 1, but the formulations are shown in Table 4. In other words, 1,6-hexanediol was used to replace thiols with a functionality greater than or equal to 3. The properties of the prepared corneal contact lenses are shown in Table 4.

[0171] Table 4 shows that the mechanical properties of the prepared corneal contact lenses deteriorated significantly after adding more than 1% of 1,6-hexanedithiol, causing the lenses to break on the mold during demolding. This indicates that the bifunctional thiol plays a dominant role as a chain transfer agent in the formulation and cannot enhance the cross-linked network.

[0172] The above description of the embodiments is intended to enable those skilled in the art to understand and apply this application. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without creative effort. Therefore, this application is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope and spirit of this application are within the scope of this application.

Claims

1. A highly ductile silicone hydrogel, characterized in that, The highly ductile silicone hydrogel is prepared by polymerization of a polymerizable composition. The polymerizable composition comprises the following components: (a) A monofunctional siloxane monomer, wherein the monofunctional siloxane monomer is selected from one or more of vinyl monoterminated polysiloxanes, acrylate monoterminated polysiloxanes and methacrylate monoterminated polysiloxanes. (b) A hydrophilic N-vinylamide monomer, wherein the hydrophilic N-vinylamide monomer is selected from one or more of the following: N-methyl-N-vinylacetamide, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-ethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-3-methoxypropyl(meth)acrylamide; (c) A hydrophobic vinyl monomer selected from one or more of the following: cyclohexyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, styrene, methylstyrene, 4-tert-butylstyrene, 4-ethoxystyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,5-dimethylstyrene, and acrylates containing a benzene ring; (g) Thiols with a functionality of 3 or greater; Based on weight, the thiols with a functionality of 3 or greater account for 0.4% to 2% of the total weight of the polymerizable composition; the monofunctional siloxane monomers account for 35% to 40% of the total weight of the polymerizable composition; the hydrophilic N-vinylamide monomers account for 40% to 50% of the total weight of the polymerizable composition; and the hydrophobic vinyl monomers account for 5% to 20% of the total weight of the polymerizable composition. The elongation of the highly ductile silicone hydrogel is 285%-439%.

2. The highly ductile silicone hydrogel as described in claim 1, characterized in that, The thiols with a functionality of 3 or greater are selected from one or more of the following: trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetra-3-mercaptopropionate, and pentaerythritol tetra(3-mercaptobutyrate).

3. The highly ductile silicone hydrogel as described in claim 2, characterized in that, The thiol with a functionality greater than or equal to 3 is pentaerythritol tetra-3-mercaptopropionate or pentaerythritol tetra(3-mercaptobutyric acid) ester.

4. The highly ductile silicone hydrogel as described in claim 1, characterized in that, On a weight basis, the thiols with a functionality of 3 or greater account for 0.48% to 1.9% of the total weight of the polymerizable composition.

5. The highly ductile silicone hydrogel according to any one of claims 1-4, characterized in that, The polymerizable composition further comprises the following components: (d) A hydroxyl-containing hydrophilic vinyl monomer, wherein the hydroxyl-containing hydrophilic vinyl monomer is a hydroxyalkyl acrylate or a hydroxyalkyl methacrylate; (e) Non-siloxane type vinyl crosslinking agents; (f) Free radical initiators.

6. The highly ductile silicone hydrogel as described in claim 5, characterized in that, The polymerizable composition further comprises the following components: (h) Ultraviolet light absorber.

7. The highly ductile silicone hydrogel as described in claim 6, characterized in that, The ultraviolet light absorber is 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole.

8. The highly ductile silicone hydrogel as described in claim 5, characterized in that, The monofunctional siloxane monomer is selected from one or more of the following: (meth)acrylic acid mono-terminated polydimethylsiloxane; The hydroxyl-containing hydrophilic vinyl monomer is selected from one or more of the following: 2-hydroxypropyl methacrylate, N-2-hydroxyethyl (meth)acrylamide, N,N-bis(hydroxyethyl)(meth)acrylamide, N-3-hydroxypropyl (meth)acrylamide, N-2-hydroxypropyl (meth)acrylamide, N-2,3-dihydroxypropyl (meth)acrylamide, N-tris(hydroxymethyl)methyl (meth)acrylamide, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, glyceryl methacrylate (GMA), di(ethylene glycol) (meth)acrylate, tri(ethylene glycol) (meth)acrylate, tetra(ethylene glycol) (meth)acrylate, poly(ethylene glycol) (meth)acrylate having a number average molecular weight of up to 1500, and poly(ethylene glycol) ethyl (meth)acrylamide having a number average molecular weight of up to 1500. The non-siloxane type vinyl crosslinker is selected from one or more of the following: ethylene glycol dimethacrylate and triethylene glycol dimethacrylate; The free radical initiator is selected from one or more of the following: peroxide, hydroperoxide, azobis(alkyl- or cycloalkylnitrile), persulfate, percarbonate or mixtures thereof.

9. The highly ductile silicone hydrogel as described in claim 5, characterized in that, The weight-average molecular weight of the monofunctional siloxane monomer is 600-1000. The acrylate containing a benzene ring includes one or more of phenyl acrylate, phenyl methacrylate, norisoborneol acrylate and norisoborneol methacrylate; The free radical initiators include, but are not limited to: benzoyl peroxide, tert-butyl peroxide, tert-amyl peroxybenzoate, 2,2-bis(tert-butylperoxy)butane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, 2,5-bis(tert-butylperoxy)-2,5-dimethyl-3-hexyne, bis(1-(tert-butylperoxy)-1-methylethyl)benzene, 1,1-bis(tert-butylperoxy)-3,3 5-Trimethylcyclohexane, di-tert-butyldiperoxyphthalate, tert-butyl hydroperoxide, tert-butyl peracetate, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, acetyl peroxide, lauroyl peroxide, decanoyl peroxide, dicetyl peroxydicarbonate, di(4-tert-butylcyclohexyl)peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, tert-butyl peroxyneopentate, tert-butyl peroxy-2-ethylhexanoate, 2,4-pentanedione peroxide, dicumyl peroxide, peracetic acid, potassium persulfate, sodium persulfate, ammonium persulfate, 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2 '-Azobis(2-amidinylpropane) dihydrochloride, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(isobutyronitrile), 2,2'-azobis-2-methylbutyronitrile, 1,1-azobis(1-cyclohexanecarboxylonitrile); 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(methyl isobutyrate), 4,4'-azobis(4-cyanopentanoic acid), and combinations thereof.

10. The highly ductile silicone hydrogel as described in claim 9, characterized in that, The free radical initiator is 2,2'-azobis-2-methylbutyronitrile.

11. The highly ductile silicone hydrogel as described in claim 1, characterized in that, The hydrophobic vinyl monomer has a refractive index greater than 1.41 and a glass transition temperature greater than or equal to 60°C.

12. A corneal contact lens, characterized in that, The corneal contact lens is made of a highly elastic silicone hydrogel as described in any one of claims 1-11.

13. The method for preparing a corneal contact lens as described in claim 12, characterized in that, The method includes the following steps: S1: A mold is provided that includes a male half mold having a raised molding surface and a female half mold having a recessed molding surface, wherein the male half mold and the female half mold are configured to receive each other, thereby forming a mold cavity between the raised molding surface and the recessed molding surface when the mold is closed. S2: Dispense a predetermined weight of the polymerizable composition into the female half-mold; S3: The male and female half-molds are fitted together to close the mold; S4: The polymerizable composition located in the mold cavity is cured to form a molded corneal contact lens; S5: The mold is separated into a male half-mold and a female half-mold, and the corneal contact lens is adhered to one of the male half-mold and the female half-mold; S6: Squeeze the half-mold with the corneal contact lens attached to it to separate the half-mold from the corneal contact lens; S7: Remove the corneal contact lens from the semi-mold using a vacuum suction device.

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