Highly oxygen permeable silicone hydrogel and method of making same

Abstract

The application discloses a kind of high oxygen permeability silicon hydrogel nanocomposites and its preparation method.The raw material according to mass fraction includes the following components: A.8-18 parts of surface modified carboxyl nanosilica;B.30-40 parts of hydroxyethyl methacrylate;C.3-7 parts of methacryloyloxy functional polyether;D.0.2-0.5 parts of N,N'-methylene bisacrylamide;E.0.3-0.8 parts of initiator.In the scheme, the surface modified carboxyl nanosilica is added, which is in a highly dispersed state in the hydrogel system, greatly improving the uniformity of the microstructure of the material. The addition of methacryloyloxy polyether can adjust the interfacial polarity of other monomers, enabling the synergistic construction of continuous oxygen permeation channels and mechanical reinforcement at the molecular level, ultimately achieving the simultaneous optimization of oxygen flux improvement, mechanical properties and long-term structural stability.

Description

Technical Field

[0001] This application relates to the technical field of hydrogel materials, and in particular to a highly oxygen-permeable silica hydrogel and its preparation method. Background Technology

[0002] As a core substrate for contact lenses, the research and development of silicone hydrogel materials focuses on achieving a synergistic improvement in both high oxygen permeability and excellent mechanical properties. According to patent documents such as US12378415B2 and JP2023164345A, existing technologies primarily attempt to balance oxygen permeability and surface hydrophilicity by adjusting the ratio of silicon molecules to hydrophilic monomers. While these patented technologies have indeed improved the oxygen transport capacity of silicone hydrogels and enhanced surface hydrophilicity to some extent by optimizing the mixing ratio of organosilicon components and hydrophilic monomers, thus improving the comfort of contact lens wear, significant room for improvement remains in terms of uniformity, mechanical properties, oxygen permeability, and long-term stability.

[0003] Therefore, existing technologies still suffer from unresolved issues such as nano-agglomeration and poor compatibility at the organic-inorganic interface, hindering the further development and application of highly oxygen-permeable silicone hydrogel materials in high-end applications such as contact lenses. This invention addresses these technological gaps by employing innovative processes such as surface grafting of hydrophilic functional groups onto nano-organosilicon and stepwise temperature-controlled polymerization, significantly improving the material's structural uniformity, mechanical properties, and long-term stability, bringing a breakthrough to the industry. Summary of the Invention

[0004] The issues to be addressed

[0005] This application aims to address at least one of the technical problems existing in the prior art. To this end, one objective of this application is to provide a nanocomposite material of highly oxygen-permeable silica hydrogel and a method for preparing the same, thereby improving the uniformity of the material structure, optimizing the mechanical properties and oxygen permeability in a modular synergistic manner, and significantly improving long-term stability and storage safety.

[0006] [Methods for Solving the Problem]

[0007] In related technologies, such as US12378415B2 and JP2023164345A, the following defects still exist due to the high hydrophobicity of silicon molecules and insufficient compatibility at the organic-inorganic interface:

[0008] First, although existing technologies achieve initial uniform dispersion of silicon hydrogel systems through blending or proportioning adjustments, the lack of effective nano-surface modification methods leads to phase separation between silicon molecules and hydrophilic monomers, resulting in significant nano-agglomeration. This agglomeration not only reduces the material's mechanical strength and elasticity (e.g., tensile strength and elongation at break are difficult to improve simultaneously) but also causes discontinuous oxygen channels, thus affecting the maximization of oxygen permeability. For example, relevant patent literature does not disclose the use of multi-scale network structures or stepwise temperature-controlled polymerization processes, resulting in a non-uniform microstructure and poor performance consistency in the obtained hydrogel system.

[0009] Secondly, existing technologies generally fail to address the problem of insufficient organic-inorganic interfacial bonding. Due to the polarity difference between hydrophobic and hydrophilic monomers in silicon molecules, the interfacial bonding is weak, causing hydrogels to easily delaminate or become structurally loose during long-term use, resulting in insufficient storage stability and long-term wear safety. For example, although oxygen flux can be increased in the short term, the mechanical properties of the material decrease significantly after simulated long-term use (such as 30 days of humid heat cycling), and the surface hydrophilicity is easily reduced, failing to guarantee the long-term stable use of contact lenses.

[0010] The aforementioned related technologies mainly employ the adjustment and blending of the ratio of silicon monomers to hydrophilic monomers. However, due to the failure to effectively address the issues of agglomeration and weak interfacial bonding, the microstructure becomes uneven and the durability of the products is insufficient. Conventional industry improvements often focus on increasing the proportion of hydrophilic monomers or introducing physical dispersants, but these measures cannot fundamentally improve silicon molecule agglomeration and are difficult to balance high oxygen permeability with stable mechanical properties. To address the hydrophobicity of silicon molecules and the low activity of nano-surfaces, some industry solutions have attempted to use polyether modification and the addition of silanols, but these have failed to achieve high uniformity through chemical bonding structures, and the polymerization process is simplistic with overly simplistic temperature control, resulting in inconsistent microstructures. This application introduces surface-grafted hydrophilic functional groups, creating strong interfacial bonding between nano-monomers and hydrophilic monomers at the molecular level. Through multi-step temperature-controlled polymerization and dynamic dispersion processes, the organic-inorganic interaction is more complete, achieving a breakthrough in the continuity and uniformity of the microstructure. This invention thus completes the creation of this invention.

[0011] This application provides a highly oxygen-permeable silicone hydrogel, the raw material of which comprises the following components in parts by weight:

[0012] A. 8-18 parts of surface-modified carboxyl-containing nano-silica;

[0013] B. 30-40 parts hydroxyethyl methacrylate;

[0014] C. 3-7 parts of methacryloxy functionalized polyether;

[0015] D. 0.2-0.5 parts of N,N'-methylenebisacrylamide;

[0016] E. 0.3-0.8 parts initiator.

[0017] In any embodiment, the particle size of the nano-silica is 10-80 nanometers.

[0018] In any embodiment, the methacryloyloxy functional polyether is a methacryloyloxy polyoxyethylene ether or an ethyleneoxy polyether.

[0019] In any embodiment, the molecular weight of the methacryloxy functional polyether is 400-2000 Daltons.

[0020] In any embodiment, the initiator is 2-hydroxy-2-methylpropionyl phenyl ketone.

[0021] In any embodiment, the amount of water used in the raw material is 34-58 parts by weight.

[0022] Secondly, this application provides a method for preparing the above-mentioned highly oxygen-permeable silica hydrogel, comprising the following steps:

[0023] S1. Disperse 8-18 parts of surface-modified carboxyl-modified nano-silica in a mixture of 30-40 parts of hydroxyethyl methacrylate and 3-7 parts of methacryloxy functional polyether, and disperse thoroughly;

[0024] S2. Add 0.2-0.5 parts of N,N'-methylenebisacrylamide and disperse thoroughly;

[0025] S3. Add 0.3-0.8 parts of initiator, disperse thoroughly, and obtain the precursor solution;

[0026] S4. The precursor solution is subjected to full polymerization reaction at 40-65℃ under an oxygen-free atmosphere to form a product liquid containing the initial hydrogel;

[0027] S5. Heat the product liquid to 75-95℃, keep it at that temperature, perform secondary crosslinking and maturation, cool and demold, wash with water to obtain a high oxygen permeable silicone hydrogel product.

[0028] In any embodiment, the polymerization reaction in step S4 takes 2-4 hours.

[0029] In any implementation, the heat preservation time in step S5 is 1.5-2.5 hours.

[0030] Thirdly, this application provides an application of the above-described high oxygen permeability silica hydrogel in the preparation of high oxygen permeability soft contact lens products.

[0031] [Invention Effects]

[0032] The nano-silica used in this application is surface-modified with hydrophilic functional carboxyl groups, resulting in a highly dispersed state in the hydrogel system and significantly improving the uniformity of the material's microstructure. Furthermore, methacryloyloxy polyether, with its polarity-regulating properties, is used as a functional additive to synergistically regulate the interfacial polarity of hydroxyethyl methacrylate and other monomers such as N,N'-methylenebisacrylamide, promoting enhanced organic-inorganic interactions. This enables the synergistic construction of continuous oxygen permeability channels and mechanical enhancement at the molecular level. Ultimately, this solution not only achieves synergistic optimization of oxygen flux, mechanical properties, and long-term structural stability but also provides reliable protection for high-end applications such as contact lenses. Detailed Implementation

[0033] Hereinafter, embodiments of the present application are disclosed in detail with appropriate reference to the detailed description. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of actually identical structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand the present application and is not intended to limit the subject matter of the claims.

[0034] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0035] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0036] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0037] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0038] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0039] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0040] Highly oxygen-permeable silicone hydrogel

[0041] As used in this article, "hydrogel" refers to a type of highly hydrophilic three-dimensional network gel that rapidly swells in water and retains a large volume of water without dissolving. Due to the presence of a cross-linked network, hydrogels can swell and retain large amounts of water; the amount of water absorbed is closely related to the degree of cross-linking. The aggregated state of a hydrogel is neither completely solid nor completely liquid. Solid behavior involves maintaining a certain shape and volume under certain conditions, while liquid behavior allows solutes to diffuse or permeate through the hydrogel.

[0042] As used in this article, “silicone hydrogel” refers to a hydrogel material containing inorganic silicon components (for example, inorganic silicon in this article refers to nano-silica).

[0043] The raw material of the highly oxygen-permeable silicone hydrogel described in this article contains the following components by weight:

[0044] A. 8-18 parts of nano-silica with surface-modified hydroxyl or carboxyl groups;

[0045] B. 30-40 parts hydroxyethyl methacrylate;

[0046] C. 3-7 parts of methacryloxy functionalized polyether;

[0047] D. 0.2-0.5 parts of N,N'-methylenebisacrylamide;

[0048] E. 0.3-0.8 parts initiator.

[0049] Based on general technical knowledge of hydrogel material preparation, it is known that acrylic monomers containing carbon-carbon double bonds, such as hydroxyethyl methacrylate, methacryloxy functionalized polyether, and N,N'-methylenebisacrylamide, are obtained through conventional processes of free radical polymerization of carbon-carbon double bonds. It should be noted that the choice of conventional free radical polymerization processes does not affect whether the technical effects claimed in this application can be implemented. Therefore, further details will not be elaborated upon here.

[0050]

Carboxyl-modified nano-silica

[0051] Those skilled in the art will understand the specific principles and methods of modifying the surface of nano-silica with hydroxyl or carboxyl groups. Since silica naturally possesses hydroxyl groups, this provides the possibility for chemical modification by reacting with carboxyl-containing modifiers (to provide carboxyl functional groups). Depending on the type of modifier, two types are generally used. A more conventional but preferred modifier is a silane coupling agent containing hydroxyl or carboxyl groups (such as carboxyethylsilanetriol, carboxysilane, etc.). Specifically, this type of modifier is hydrolyzed under alkaline conditions. The hydrolyzed silane undergoes a condensation reaction with the hydroxyl groups on the silica surface, forming stable Si-O-Si bonded carboxyl functional groups, which are thus stably anchored on the particle surface. Another modifier is anhydride. It is understood that in an aqueous dispersion medium, the anhydride groups contained in the modifier are ultimately modified onto the silica in the form of carboxyl groups through hydrolysis, as described in Chinese CN108410440A.

[0052] The above discussion concerns direct modification with carboxyl-containing modifiers. In addition, indirect modification can also be used, such as first modifying the silica surface with an amino-containing modifier, and then replacing the amino group with a carboxyl-containing modifier. This technique can be referenced in CN113292984A: first, an aminosiloxane coupling agent is used as the modifier. Aminopropyltriethoxysilane and silica nanoparticles are refluxed in toluene, an organic solvent, for a period of time. After several washes with water and ethanol, amino-modified nanoparticles are obtained. Then, the amino-modified nanoparticles, succinic anhydride, and triethylamine are added to N,N-dimethylformamide, an organic solvent, and reacted for a period of time. After several washes with water and ethanol, carboxyl-modified silica nanoparticles are obtained.

[0053] To facilitate compatibility between nano-silica and polymers obtained from the polymerization reactions of monomers such as hydroxyethyl methacrylate, methacryloxy functionalized polyether, and methacryloyloxy functionalized polyether, a dispersion is preferred as the addition method in this application. Dispersions also avoid the cumbersome separation process associated with solid silica. Of course, if solid nano-silica is unavoidable due to limited commercial availability, it can be dispersed using methods such as ultrasound to form a dispersion (adding conventional siloxane coupling agents or adjusting the pH during dispersion), followed by surface modification with carboxyl groups.

[0054] In any embodiment, the particle size of the nano-silica is 10-80 nanometers. This suitable particle size ensures that the nano-silica can achieve good bonding with other monomers, thereby improving the binding force of the nano-silica in the hydrogel system.

[0055] In any embodiment, the methacryloyloxy functional polyether is a methacryloyloxy polyoxyethylene ether or an ethyleneoxy polyether.

[0056] In any embodiment, the molecular weight of the methacryloxy functional polyether is 400-2000 Daltons.

[0057] In any embodiment, the initiator is 2-hydroxy-2-methylpropionyl phenyl ketone, or other forms.

[0058] In any embodiment, the amount of water used in the raw material is 34-58 parts by weight.

[0059]

Preparation Method

[0060] The preparation method of the above-mentioned highly oxygen-permeable silica hydrogel includes the following steps:

[0061] S1. Disperse 8-18 parts of surface-modified carboxyl-modified nano-silica in a mixture of 30-40 parts of hydroxyethyl methacrylate and 3-7 parts of methacryloxy functional polyether, and disperse thoroughly;

[0062] S2. Add 0.2-0.5 parts of N,N'-methylenebisacrylamide and disperse thoroughly;

[0063] S3. Add 0.3-0.8 parts of initiator, disperse thoroughly, and obtain the precursor solution;

[0064] S4. Add the precursor solution to the contact lens mold and perform a full polymerization reaction at 40-65℃ to carry out primary crosslinking;

[0065] S5. Next, control the temperature at 75-95℃ to carry out secondary crosslinking and maturation. After the reaction is completed, demold and wash with water to obtain the high oxygen permeability silicone hydrogel product.

[0066] In any embodiment, the polymerization reaction in step S4 takes 2-4 hours.

[0067] In any implementation, the heat preservation time in step S5 is 1.5-2.5 hours.

[0068] Without limiting the implementation method, in step S1, the rotation speed of the high-speed shear emulsifier is 9000-12000 rpm and the dispersion time is 35-50 minutes.

[0069] Without any restrictions on the implementation method, after cooling and demolding, the product is thoroughly washed with deionized water until the content of unreacted monomers is less than 0.1% by mass.

[0070] [Implementation process of the examples and comparative examples]

[0071] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0072] Example 1

[0073] The raw materials for highly oxygen-permeable silicone hydrogel are as follows, in parts by weight:

[0074] Surface-modified carboxyl-modified nano-silica: 12 parts

[0075] Hydroxyethyl methacrylate (HEA): 35 parts

[0076] Methacryloxy functionalized polyether: 5 parts

[0077] N,N'-Methylenebisacrylamide: 0.4 parts

[0078] 2-Hydroxy-2-methylpropionylphenyl ketone (photoinitiator): 0.5 parts

[0079] The specific preparation method is as follows:

[0080] S1: Disperse 12 parts of surface-modified carboxyl nano-silica in a mixture of 35 parts of hydroxyethyl methacrylate and 5 parts of methacryloxy functional polyether. Disperse using a high-speed shear emulsifier with a speed of 8000-12000 rpm for 30-50 minutes and control the temperature at 20-30℃.

[0081] S2: Add 0.4 parts of N,N'-methylenebisacrylamide to the dispersion system and continue stirring for 10-20 minutes to fully dissolve the crosslinking agent.

[0082] S3: Slowly add 0.5 parts of 2-hydroxy-2-methylpropionyl phenyl ketone to the mixture, stir evenly, then add 47.1 parts of deionized water and continue stirring for 20-30 minutes to obtain a homogeneous precursor solution.

[0083] S4: Place the precursor solution under an inert atmosphere (nitrogen) and polymerize at 40-65℃ for 2-4 hours to complete the first-stage polymerization and form the initial hydrogel network.

[0084] S5: Heat to 75-95℃ and maintain for 1.5-2.5 hours to carry out secondary cross-linking and maturation, promote the full integration of nanofillers and main chains, and form a dense and uniform multi-scale network structure.

[0085] S6: Cool to room temperature, demold, wash with water to remove unreacted monomers, and obtain a high oxygen permeability silicone hydrogel product.

[0086] Example 2

[0087] The only difference from Example 1 is that the content of surface-modified carboxyl nano-silica was adjusted to 8 parts, the content of hydroxyethyl methacrylate was increased to 40 parts, and the proportions of other components were adjusted accordingly.

[0088] The raw materials for highly oxygen-permeable silicone hydrogel are as follows, in parts by weight:

[0089] Surface-modified carboxyl-modified nano-silica: 8 parts

[0090] Hydroxyethyl methacrylate (HEA): 40 parts

[0091] Methacryloxy functionalized polyether: 3 parts

[0092] N,N'-Methylenebisacrylamide: 0.3 parts

[0093] 2-Hydroxy-2-methylpropionyl phenyl ketone: 0.5 parts

[0094] Deionized water: 48.2 parts.

[0095] Example 3

[0096] The only difference from Example 1 is that the content of surface-modified carboxyl nano-silica is increased to 16 parts, hydroxyethyl methacrylate is reduced to 30 parts, and methacryloxy functional polyether is increased to 7 parts.

[0097] The raw materials for highly oxygen-permeable silicone hydrogel are as follows, in parts by weight:

[0098] Surface-modified carboxyl-modified nano-silica: 16 parts

[0099] Hydroxyethyl methacrylate (HEA): 30 parts

[0100] Methacryloxy functionalized polyether: 7 parts

[0101] N,N'-Methylenebisacrylamide: 0.5 parts

[0102] 2-Hydroxy-2-methylpropionyl phenyl ketone: 0.8 parts

[0103] Deionized water: 45.7 parts.

[0104] Example 4

[0105] The only difference from Example 1 is that the content of surface-modified carboxyl nano-silica is 10 parts, hydroxyethyl methacrylate is 38 parts, and methacryloyloxy functional polyether is 6 parts.

[0106] The raw materials for highly oxygen-permeable silicone hydrogel are as follows, in parts by weight:

[0107] Surface-modified carboxyl-modified nano-silica: 10 parts

[0108] Hydroxyethyl methacrylate (HEA): 38 parts

[0109] Methacryloxy functionalized polyether: 6 parts

[0110] N,N'-Methylenebisacrylamide: 0.4 parts

[0111] 2-Hydroxy-2-methylpropionyl phenyl ketone: 0.6 parts

[0112] Deionized water: 45 parts.

[0113] Example 5

[0114] The only difference from Example 1 is that it contains 12 parts of surface-modified carboxyl nano-silica, 33 parts of hydroxyethyl methacrylate, and 4 parts of methacryloxy functional polyether.

[0115] The raw materials for highly oxygen-permeable silicone hydrogel are as follows, in parts by weight:

[0116] Surface-modified carboxyl-modified nano-silica: 12 parts

[0117] Hydroxyethyl methacrylate (HEA): 33 parts

[0118] Methacryloxy functionalized polyether: 4 parts

[0119] N,N'-Methylenebisacrylamide: 0.3 parts

[0120] 2-Hydroxy-2-methylpropionyl phenyl ketone: 0.4 parts

[0121] Deionized water: 50.3 parts.

[0122] Example 6

[0123] The only difference from Example 1 is that the content of N,N'-methylenebisacrylamide is increased to 0.5 parts, hydroxyethyl methacrylate is 36 parts, and surface-modified carboxyl nano-silica is 14 parts.

[0124] The raw materials for highly oxygen-permeable silicone hydrogel are as follows, in parts by weight:

[0125] Surface-modified carboxyl-modified nano-silica: 14 parts

[0126] Hydroxyethyl methacrylate (HEA): 36 parts

[0127] Methacryloxy functionalized polyether: 5 parts

[0128] N,N'-Methylenebisacrylamide: 0.5 parts

[0129] 2-Hydroxy-2-methylpropionyl phenyl ketone: 0.7 parts

[0130] Deionized water: 43.8 parts.

[0131] Example 7

[0132] The only difference from Example 1 is that the content of 2-hydroxy-2-methylpropionyl phenyl ketone is increased to 0.8 parts, the content of surface-modified carboxyl nano-silica is 9 parts, and the content of hydroxyethyl methacrylate is 34 parts.

[0133] The raw materials for highly oxygen-permeable silicone hydrogel are as follows, in parts by weight:

[0134] Surface-modified carboxyl-modified nano-silica: 9 parts

[0135] Hydroxyethyl methacrylate (HEA): 34 parts

[0136] Methacryloxy functionalized polyether: 6 parts

[0137] N,N'-Methylenebisacrylamide: 0.4 parts

[0138] 2-Hydroxy-2-methylpropionyl phenyl ketone: 0.8 parts

[0139] Deionized water: 49.8 parts.

[0140] Example 8

[0141] The only difference from Example 1 is that the content of methacryloxy functional polyether is increased to 7 parts, the content of surface-modified carboxyl nano silica is 15 parts, and the content of hydroxyethyl methacrylate is 37 parts.

[0142] The raw materials for highly oxygen-permeable silicone hydrogel are as follows, in parts by weight:

[0143] Surface-modified carboxyl-modified nano-silica: 15 parts

[0144] Hydroxyethyl methacrylate (HEA): 37 parts

[0145] Methacryloxy functionalized polyether: 7 parts

[0146] N,N'-Methylenebisacrylamide: 0.3 parts

[0147] 2-Hydroxy-2-methylpropionyl phenyl ketone: 0.6 parts

[0148] Deionized water: 40.1 parts.

[0149] Example 9

[0150] The only difference from Example 1 is that the amount of hydroxyethyl methacrylate is 39 parts, the amount of surface-modified carboxyl nano-silica is 11 parts, and the amount of N,N'-methylenebisacrylamide is 0.2 parts.

[0151] The raw materials for highly oxygen-permeable silicone hydrogel are as follows, in parts by weight:

[0152] Surface-modified carboxyl-modified nano-silica: 11 parts

[0153] Hydroxyethyl methacrylate (HEA): 39 parts

[0154] Methacryloxy functionalized polyether: 4 parts

[0155] N,N'-Methylenebisacrylamide: 0.2 parts

[0156] 2-Hydroxy-2-methylpropionyl phenyl ketone: 0.5 parts

[0157] Deionized water: 45.3 parts.

[0158] Comparative Example 1

[0159] The only difference from Example 1 is that 12 parts of unmodified carboxyl nano-organic silicon filler were used; all other components and processes were the same as in Example 1.

[0160] Comparative Example 2

[0161] Based on Example 1, the following conditions were changed: no methacryloyloxy functional polyether (functional additive) was added, and the proportions of other components and the process flow were the same as in Example 1.

[0162] Comparative Example 3

[0163] Based on Example 1, the stepwise temperature-controlled polymerization process is omitted, and polymerization is carried out directly at 80-95℃ for 4 hours in one go, while other operations remain unchanged.

[0164] This is used to compare the impact of stepwise temperature-controlled polymerization processes on material properties.

[0165] Comparative Example 4

[0166] Based on Example 1, the content of surface-modified carboxyl nano-silica was increased to 20 parts, while the proportions of other components were reduced accordingly, and the process flow remained unchanged.

[0167]

evaluate

[0168] A: Test of oxygen permeability of hydrogel material

[0169] Evaluation participants: Examples 1-9, Comparative Examples 1-4;

[0170] Experimental equipment: Oxygen permeability meter, model 201T, manufactured by Creathch / Rehder-Dev Co.;

[0171] Evaluation method:

[0172] The hydrogel was soaked in physiological saline for 48 hours. The oxygen permeability was tested at 35°C and 98% relative humidity according to the test method of GB / T11417.7-2012. The oxygen permeability coefficient was tested.

[0173] Experimental data: Oxygen permeability coefficient (10 -11 cm 2 (mLO2 / s·mL·mmHg).

[0174] B: Test of mechanical properties of hydrogel material

[0175] Experimental participants: Examples 1-9, Comparative Examples 1-4;

[0176] Experimental equipment: Electronic universal testing machine, model Instron 5943, manufactured by Instron Corporation;

[0177] Experimental methods:

[0178] S1: Cut each sample into dumbbell-shaped strips of 10mm×50mm with a thickness of 0.1-0.15mm, and equilibrate at 25℃ and 50%RH for 24 hours.

[0179] S2: Mounted on the fixture of the electronic universal testing machine, tensile speed 50mm / min.

[0180] S3: Record the elongation at break (%), breaking strength (MPa), and elastic modulus (MPa). Test each sample 5 times and take the average value.

[0181] Experimental data: elongation at break, breaking strength, and elastic modulus of each sample.

[0182] C: Test of long-term stability and storage safety of material

[0183] Experimental participants: Examples 1-9, Comparative Examples 1-4;

[0184] Experimental equipment: constant temperature and humidity chamber, model Binder KBF 115, manufactured by Binder GmbH;

[0185] Experimental methods:

[0186] S1: Each sample was subjected to accelerated aging at 55℃ and 90% humidity for 30 days.

[0187] S2: Samples were taken after aging to test their oxygen permeability (Dk / t) and elongation at break.

[0188] S3: Observe whether there are any phenomena such as delamination, whitening, or agglomeration on the surface of the material, and record the weight loss rate.

[0189] Experimental data: changes in oxygen permeability, elongation at break, weight loss, and surface structure after aging.

[0190] D: Microscopic analysis of dispersion and interfacial bonding force of nanofiller

[0191] Experimental participants: Examples 1-9, Comparative Examples 1-4;

[0192] Experimental equipment: Transmission electron microscope, model JEOL JEM-2100, manufactured by JEOL Ltd.

[0193] Experimental methods:

[0194] S1: Take slices of each sample (approximately 100 nm thick) and place them on a copper mesh carrier.

[0195] S2: Observe the distribution and interface structure of nanofillers under a voltage of 200kV.

[0196] S3: Take 3-5 field-of-view images to statistically analyze the agglomeration size and distribution uniformity of the nanofiller.

[0197] Experimental data: Surface structure changes.

[0198] Table 1 Test results of each embodiment and comparative example

[0199]

[0200] As can be seen from the data in the table above, the key performance indicators such as oxygen permeability, elongation at break, and elastic modulus of Examples 1-6 are significantly higher than those of the comparative examples, and they also exhibit high performance retention after aging, stable surface structure, and no obvious agglomeration or delamination. This is mainly due to the high dispersibility of the surface-grafted hydrophilic group nano-organosilicon filler, the synergistic effect of the polarity regulating agent, and the optimization of the stepwise temperature-controlled polymerization process. In contrast, samples such as Comparative Example 1 (unmodified carboxyl groups), Comparative Example 3 (without stepwise temperature control), and Comparative Example 4 (excess nano-silica) all showed low oxygen permeability, poor mechanical properties, severe performance degradation after aging, and obvious surface agglomeration and delamination, indicating that traditional methods are difficult to balance the uniformity of the material's microstructure and performance stability. Meanwhile, the nano-fillers in Examples 1-5 are uniformly dispersed, with tight interfacial bonding and no obvious agglomeration. Comparative Examples 1, 3, and 4 have large agglomerate sizes, uneven distribution, and interfacial delamination, thus confirming the synergistic effect of the technical features of this invention.

[0201] Specifically, surface-modified carboxyl-modified nano-silica can significantly enhance the interfacial bonding force between the filler and the hydrophilic monomer, inhibit agglomeration, and form continuous oxygen-permeable channels; polarity-regulating auxiliaries further enhance organic-inorganic interactions and improve the uniformity of microstructure; stepwise temperature-controlled polymerization process ensures the full integration of nano-fillers with the main chain, improving mechanical strength and long-term stability.

[0202] The above embodiments are merely illustrative of the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A nanocomposite material of highly oxygen-permeable silica hydrogel, characterized in that, Its raw materials contain the following components by weight: A. 8-18 parts of surface-modified carboxyl-containing nano-silica; B. 30-40 parts hydroxyethyl methacrylate; C. 3-7 parts of methacryloxy functionalized polyether; D. 0.2-0.5 parts of N,N'-methylenebisacrylamide; E. 0.3-0.8 parts initiator.

2. The nanocomposite material of the highly oxygen-permeable silica hydrogel according to claim 1, characterized in that, The particle size of the nano-silica is 10-80 nanometers.

3. The nanocomposite material of the highly oxygen-permeable silica hydrogel according to claim 1, characterized in that, The methacryloyloxy functional polyether is a methacryloyloxy polyoxyethylene ether or an ethyleneoxy polyether.

4. The nanocomposite material of the highly oxygen-permeable silica hydrogel according to claim 1, characterized in that, The molecular weight of the methacryloyloxy functional polyether is 400-2000 Daltons.

5. The nanocomposite material of the highly oxygen-permeable silica hydrogel according to claim 1, characterized in that, The initiator is 2-hydroxy-2-methylpropionyl phenyl ketone.

6. The nanocomposite material of the highly oxygen-permeable silica hydrogel according to claim 1, characterized in that, The amount of water used in the raw material is 34-58 parts by weight.

7. A method for preparing a nanocomposite material of highly oxygen-permeable silica hydrogel as described in claim 1, characterized in that, Includes the following steps: S1. Disperse 8-18 parts of surface-modified carboxyl-modified nano-silica in a mixture of 30-40 parts of hydroxyethyl methacrylate and 3-7 parts of methacryloxy functional polyether, and disperse thoroughly; S2. Add 0.2-0.5 parts of N,N'-methylenebisacrylamide and disperse thoroughly; S3. Add 0.3-0.8 parts of initiator, disperse thoroughly, and obtain the precursor solution; S4. The precursor solution is subjected to full polymerization reaction at 40-65℃ under an oxygen-free atmosphere to form a product liquid containing the initial hydrogel; S5. Heat the product liquid to 75-95℃, keep it at that temperature, perform secondary crosslinking and maturation, cool and demold, wash with water to obtain a high oxygen permeable silicone hydrogel product.

8. The method for preparing the nanocomposite material of highly oxygen-permeable silica hydrogel according to claim 7, characterized in that, In step S4, the polymerization reaction takes 2-4 hours.

9. The method for preparing the nanocomposite material of highly oxygen-permeable silica hydrogel according to claim 7, characterized in that, In step S5, the heat preservation time is 1.5-2.5 hours.

10. The application of a high oxygen permeability silica hydrogel nanocomposite material as described in claim 1 in the preparation of high oxygen permeability soft contact mirror products.

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