Contact lens silicon hydrogel material with good flexibility and preparation method thereof

Abstract

The invention relates to the field of silicone hydrogel materials, in particular to a contact lens silicone hydrogel material with good flexibility and a preparation method thereof. The preparation method comprises the following steps: firstly, carrying out cation ring opening polymerization under 350-370 nm UV light to form a prepolymer A containing unreacted epoxy groups and vinyl; and then mixing the prepolymer A with an amido-containing hydrophilic monomer, a free radical cross-linking agent and a photothermal initiator, and carrying out second-stage polymerization under 380-410 nm UV light to form a three-dimensional network structure with an ether bond flexible interface and C-C bond strength. The method breaks through the phase separation bottleneck of traditional single-stage polymerization, the phase separation size is reduced, and the optical transparency and stability are improved. Through chemical bridging of an epoxy group and an amide group, molecular-level bonding of a siloxane phase and a water phase is realized, and flexibility and wearing comfort are improved. By introducing the flexible chain segment regulator, the flexibility of the molecular chain is enhanced, the modulus is reduced, and meanwhile, high oxygen permeability and low protein adsorbability are kept.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of silicone hydrogel materials, in particular to a soft contact lens silicone hydrogel material and a preparation method thereof. BACKGROUND

[0002] Silicone hydrogel has become the mainstream material of modern contact lenses due to its high oxygen permeability, hydrophilicity and biocompatibility of organic silicon material and hydrogel.

[0003] In the prior art, in order to improve the hydrophilicity of the silicone hydrogel material, the content of siloxane monomer is often increased, resulting in an increase in the modulus of the material and a decrease in the flexibility. High modulus materials have poor comfort and are easy to cause corneal compression and foreign body sensation, especially for long-wearing or sensitive eye patients. Although reducing the modulus can improve the comfort, it often sacrifices the oxygen permeability or mechanical strength. In addition, the siloxane phase (hydrophobic) and the water phase (hydrophilic) are not compatible in nature, and macroscopic or microscopic phase separation easily occurs. Severe phase separation not only affects the optical transparency, but also causes uneven toughness and elasticity of the material, and long-term use may cause performance degradation or increased adsorption of precipitates. The existing method usually uses surface hydrophilic modification to obtain acceptable surface wettability and anti-precipitate adsorption capacity, but the modification layer usually has durability problems, affecting the long-term wearing performance and safety.

[0004] Therefore, according to the related technical problems in the above, it is urgent to develop a soft contact lens silicone hydrogel material and a preparation method thereof. SUMMARY

[0005] Therefore, the present application aims to develop a soft contact lens silicone hydrogel material with high oxygen permeability, high water content, low modulus, high elongation at break and good biocompatibility, and a preparation method thereof.

[0006] Based on the above purpose, the present application provides a soft contact lens silicone hydrogel material and a preparation method thereof.

[0007] A preparation method of a soft contact lens silicone hydrogel material, comprising the following preparation steps: Step S1: mixing an epoxy-containing cyclosiloxane monomer, a hydrophilic hydroxyl-containing vinyl monomer, a flexible chain segment regulator, a silicon-containing crosslinking agent and a cationic photoinitiator, and performing first-stage cationic ring-opening polymerization under wavelength 350-370 nm UV light irradiation, the light intensity is controlled at 30 mW / cm², and the light irradiation time is 15-20 min, to obtain a pre-polymer A containing unreacted epoxy groups and vinyl groups; Step S2: mixing a hydrophilic amide-containing monomer, a free radical crosslinking agent and a free radical photothermal initiator to obtain a mixture B; Step S3: Prepolymer A and mixture B were thoroughly mixed, the vacuum degree was controlled at -0.09 MPa to -0.1 MPa, vacuum degassing was performed for 15-30 min, and the second stage polymerization reaction was carried out under UV light with a wavelength of 380-410 nm and the light intensity was controlled at 30 mW / cm 2 , irradiate with light for 15-20 minutes, heat to 50℃-60℃, react for 20-30 minutes to obtain contact lens silicone hydrogel material.

[0008] The weight parts of the raw materials are as follows: 20-30 parts by weight of an epoxy-containing cyclosiloxane monomer, 10-12 parts by weight of a hydroxyl-containing hydrophilic vinyl monomer, 5-8 parts by weight of a flexible segment regulator, 3-8 parts by weight of a silicon-containing crosslinking agent, 0.3-0.8 parts by weight of a cationic photoinitiator, 10-12 parts by weight of an amide-containing hydrophilic monomer, 3-7 parts by weight of a free radical crosslinking agent, and 0.2-0.6 parts by weight of a free radical photothermal initiator.

[0009] Preferably, the epoxy-containing cyclosiloxane monomer is 1,3,5,7-tetramethyl-3-(2,3-epoxypropoxypropyl)cyclotetrasiloxane or 1,3,5,7-tetramethyl-3-(4-epoxycyclohexyl)cyclotetrasiloxane.

[0010] Preferably, the hydroxyl-containing hydrophilic vinyl monomer is 2-hydroxyethyl methacrylate or glycerol methacrylate.

[0011] Preferably, the flexible segment regulator is methacryloxy polysiloxane.

[0012] Preferably, the silicon-containing crosslinking agent is tetramethyldisiloxane dimethacrylate.

[0013] Preferably, the cationic photoinitiator is bis(4-tert-butylphenyl)iodide hexafluorophosphate.

[0014] Preferably, the prepolymer A is controlled to have an epoxy conversion rate of 40%-50% and an Mn of 2500-4000 Da.

[0015] Preferably, the amide-containing hydrophilic monomer is N-vinyl pyrrolidone or N,N-dimethylacrylamide, and the free radical photothermal initiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone.

[0016] Preferably, the free radical crosslinking agent is polyethylene glycol dimethacrylate with an Mn of 400-600 Da.

[0017] A contact lens silicone hydrogel material with good flexibility is prepared by the above-mentioned preparation method of the contact lens silicone hydrogel material with good flexibility.

[0018] Beneficial effects of the present invention: 1. The present invention uses wavelength-controlled cationic / radical dual-stage polymerization to accurately retain the epoxy group activity of prepolymer A. In the second stage, the synergistic reaction of epoxy ring opening and vinyl copolymerization is triggered directionally, avoiding competition from side reactions, forming a three-dimensional network with both ether bond flexible interface and C-C bond strength, breaking through the phase separation bottleneck of traditional single-stage polymerization.

[0019] 2. The residual epoxy groups in prepolymer A undergo a ring-opening reaction with the amide groups in mixture B, forming a chemical bridge and achieving molecular-level bonding between the siloxane phase and the aqueous phase. This chemical bridge significantly reduces the phase separation size, ensuring the optical clarity and long-term stability of the material.

[0020] 3. The flexible segment regulator introduces long-chain siloxane units, which, combined with the flexible ether bonds generated by epoxy ring opening, significantly reduces the rigidity of the cross-linked network, improves the flexibility and elongation at break of the material, and reduces corneal pressure.

[0021] 4. The functionalized grouping of hydrophilic monomers forms uniform hydrophilic microdomains through chemical bridging. This significantly reduces protein adsorption while increasing the material's moisture content. Low contact angles can be achieved without the need for surface coatings, solving the problem of easy shedding of surface modification layers in traditional silicone hydrogels. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0023] Example 1: A method for preparing a contact lens silicone hydrogel material with good flexibility, comprising the following preparation steps: S1: 25 parts by weight of 1,3,5,7-tetramethyl-3-(2,3-epoxypropoxypropyl)cyclotetrasiloxane, 11 parts by weight of 2-hydroxyethyl methacrylate, 6.5 parts by weight of methacryloxypolysiloxane, 5.5 parts by weight of tetramethyldisiloxane dimethacrylate and 0.55 parts by weight of bis(4-tert-butylbenzene)iodide hexafluorophosphate were mixed uniformly; S2: Under UV light with a wavelength of 360 nm, the light intensity was controlled at 30 mW / cm 2 , irradiated for 17.5min, cationic ring-opening polymerization reaction, the degree of reaction was controlled so that the epoxy conversion was 45%, to obtain a prepolymer A containing unreacted epoxy groups and vinyl groups, the number average molecular weight (Mn) of the prepolymer A was 3257Da; S3: 11 parts by weight of N-vinyl pyrrolidone, 5 parts by weight of polyethylene glycol dimethacrylate (Mn = 500 Da), and 0.4 parts by weight of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone were mixed to obtain a mixture B; S4: The prepolymer A and the mixture B were fully mixed, the vacuum degree was controlled at -0.1 MPa, and vacuum degassing was performed for 20 min. Under UV light with a wavelength of 395 nm, the light intensity was controlled at 30 mW / cm 2 , irradiate with light for 18 minutes, carry out polymerization reaction, raise the temperature to 55°C, and continue the reaction for 25 minutes to finally obtain the contact lens silicone hydrogel material.

[0024] Example 2: A method for preparing a contact lens silicone hydrogel material with good flexibility, comprising the following preparation steps: S1: 20 parts by weight of 1,3,5,7-tetramethyl-3-(2,3-epoxypropoxypropyl)cyclotetrasiloxane, 10 parts by weight of 2-hydroxyethyl methacrylate, 5 parts by weight of methacryloxypolysiloxane, 3 parts by weight of tetramethyldisiloxane dimethacrylate and 0.3 parts by weight of bis(4-tert-butylbenzene)iodine hexafluorophosphate were mixed uniformly; S2: Under UV light with a wavelength of 350 nm, the light intensity was controlled at 30 mW / cm 2 , irradiated with light for 15 min, and cationic ring-opening polymerization was carried out. The reaction degree was controlled so that the epoxy conversion rate was 40%, and a prepolymer A containing unreacted epoxy groups and vinyl groups was obtained. The number average molecular weight (Mn) of the prepolymer A was 2510 Da; S3: 10 parts by weight of N-vinyl pyrrolidone, 3 parts by weight of polyethylene glycol dimethacrylate (Mn = 400 Da), and 0.2 parts by weight of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone were mixed to obtain a mixture B; S4: The prepolymer A and the mixture B were fully mixed, the vacuum degree was controlled at -0.09 MPa, and the vacuum degassing was carried out for 30 min. Under the UV light with a wavelength of 380 nm, the light intensity was controlled at 30 mW / cm 2 , irradiate with light for 15 minutes, carry out polymerization reaction, raise the temperature to 50℃, and continue the reaction for 20 minutes to finally obtain contact lens silicone hydrogel material.

[0025] Example 3: A method for preparing a contact lens silicone hydrogel material with good flexibility, comprising the following preparation steps: S1: 22 parts by weight of 1,3,5,7-tetramethyl-3-(2,3-epoxypropoxypropyl)cyclotetrasiloxane, 10.5 parts by weight of 2-hydroxyethyl methacrylate, 5.5 parts by weight of methacryloxypolysiloxane, 4 parts by weight of tetramethyldisiloxane dimethacrylate and 0.35 parts by weight of bis(4-tert-butylbenzene)iodide hexafluorophosphate were mixed uniformly; S2: Under UV light with a wavelength of 355 nm, the light intensity was controlled at 30 mW / cm 2 , irradiated with light for 16 minutes, and cationic ring-opening polymerization was carried out. The reaction degree was controlled so that the epoxy group conversion rate was 42%, and a prepolymer A containing unreacted epoxy groups and vinyl groups was obtained. The number average molecular weight (Mn) of the prepolymer A was controlled at 2764 Da.

[0026] S3: 10.5 parts by weight of N-vinyl pyrrolidone, 3.5 parts by weight of polyethylene glycol dimethacrylate (Mn = 450 Da), and 0.3 parts by weight of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone were mixed to obtain a mixture B; S4: The prepolymer A and the mixture B were fully mixed, the vacuum degree was controlled at -0.09 MPa, and the vacuum degassing was carried out for 25 min. The mixture was irradiated with UV light of wavelength 390 nm and the illumination intensity was controlled at 30 mW / cm 2 , irradiate with light for 16 minutes, carry out polymerization reaction, raise the temperature to 52°C, and continue the reaction for 22 minutes to finally obtain the contact lens silicone hydrogel material.

[0027] Example 4: A method for preparing a contact lens silicone hydrogel material with good flexibility, comprising the following preparation steps: S1: 28 parts by weight of 1,3,5,7-tetramethyl-3-(2,3-epoxypropoxypropyl)cyclotetrasiloxane, 11.5 parts by weight of 2-hydroxyethyl methacrylate, 7.5 parts by weight of methacryloxypolysiloxane, 7 parts by weight of tetramethyldisiloxane dimethacrylate and 0.7 parts by weight of bis(4-tert-butylbenzene)iodide hexafluorophosphate were mixed uniformly; S2: Under UV light with a wavelength of 365 nm, the light intensity was controlled at 30 mW / cm 2 , irradiated with light for 19 minutes, and cationic ring-opening polymerization was carried out. The reaction degree was controlled so that the epoxy conversion rate was 48%, and a prepolymer A containing unreacted epoxy groups and vinyl groups was obtained. The number average molecular weight (Mn) of the prepolymer A was controlled at 3792 Da; S3: 11.5 parts by weight of N-vinyl pyrrolidone, 6.5 parts by weight of polyethylene glycol dimethacrylate (Mn = 550 Da), and 0.5 parts by weight of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone were mixed to obtain a mixture B; S4: Prepolymer A and mixture B were fully mixed, the vacuum degree was controlled at -0.09 MPa, and vacuum degassing was performed for 20 min. Under UV light with a wavelength of 400 nm, the light intensity was controlled at 30 mW / cm 2 , irradiate with light for 19 minutes, carry out self-polymerization reaction, heat to 58°C, continue to react for 28 minutes, and finally obtain contact lens silicone hydrogel material.

[0028] Example 5: A method for preparing a contact lens silicone hydrogel material with good flexibility, comprising the following preparation steps: S1: 30 parts by weight of 1,3,5,7-tetramethyl-3-(2,3-epoxypropoxypropyl)cyclotetrasiloxane, 12 parts by weight of 2-hydroxyethyl methacrylate, 8 parts by weight of methacryloxypolysiloxane, 8 parts by weight of tetramethyldisiloxane dimethacrylate and 0.8 parts by weight of bis(4-tert-butylbenzene)iodine hexafluorophosphate were mixed uniformly; S2: Under UV light with a wavelength of 370 nm, the light intensity was controlled at 30 mW / cm 2 , irradiating with light for 20 minutes, and carrying out cationic ring-opening polymerization reaction, controlling the reaction degree so that the epoxy group conversion rate is 50%, and obtaining prepolymer A containing unreacted epoxy groups and vinyl groups, and the number average molecular weight (Mn) of prepolymer A is controlled at 4000 Da; S3: 12 parts by weight of N-vinyl pyrrolidone, 7 parts by weight of polyethylene glycol dimethacrylate (Mn = 600 Da), and 0.6 parts by weight of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone were mixed to obtain a mixture B; S4: The prepolymer A and the mixture B were fully mixed, the vacuum degree was controlled at -0.1 MPa, and the vacuum degassing was carried out for 15 min. The UV light with a wavelength of 410 nm was irradiated at an intensity of 30 mW / cm 2 , irradiate with light for 20 minutes, carry out polymerization reaction, raise the temperature to 60°C, and continue the reaction for 30 minutes to finally obtain contact lens silicone hydrogel material.

[0029] Comparative Example 1: Compared with Example 1, this comparative example does not add methacryloyloxy polysiloxane in step S1. The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, a contact lens silicone hydrogel material is obtained.

[0030] Comparative Example 2: Compared with Example 1, this comparative example only replaces "1,3,5,7-tetramethyl-3-(2,3-epoxypropoxypropyl)cyclotetrasiloxane" with "1,3,5,7-tetramethylcyclotetrasiloxane" of equal mass. The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, a contact lens silicone hydrogel material is obtained.

[0031] Comparative Example 3: Compared with Example 1, in step S2, the UV irradiation time was extended to 40 min to achieve an epoxy group conversion rate of 100%. The remaining steps and parameters were the same and will not be repeated in this comparative example. Finally, a contact lens silicone hydrogel material was obtained.

[0032] Comparative Example 4: Compared with Example 1, this comparative example only replaces "polyethylene glycol dimethacrylate" with "ethylene glycol dimethacrylate" of equal mass. The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, a contact lens silicone hydrogel material is obtained.

[0033] Comparative Example 5: A method for preparing a contact lens silicone hydrogel material with good flexibility, comprising the following preparation steps: S1: 25 parts by weight of 1,3,5,7-tetramethyl-3-(2,3-glycidoxypropyl) cyclotetrasiloxane, 11 parts by weight of 2-hydroxyethyl methacrylate, 6.5 parts by weight of methacryloxy polysiloxane, 5.5 parts by weight of tetramethyldisiloxane dimethacrylate and 0.55 parts by weight of bis(4-tert-butylbenzene)iodine hexafluorophosphate were mixed to obtain a mixture A; S2: 11 parts by weight of N-vinyl pyrrolidone, 5 parts by weight of polyethylene glycol dimethacrylate (Mn = 500 Da), and 0.4 parts by weight of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone were mixed to obtain a mixture B; S3: Mix mixture A and mixture B thoroughly and evenly, control the vacuum degree at -0.1 MPa, and perform vacuum degassing for 20 minutes. Then, irradiate with UV light of wavelength 395 nm and intensity of illumination at 30 mW / cm2 for 18 minutes to carry out free radical polymerization reaction. Then, heat to 55°C and continue the reaction for 25 minutes to finally obtain the silicone hydrogel material for contact lenses.

[0034] The performance tests of the contact lens silicone hydrogel materials prepared in Examples 1-5 and Comparative Examples 1-5 were performed: Test the elastic modulus and elongation at break of silicone hydrogel materials for glasses. The test standard refers to ISO 18369-4:2017. The oxygen permeability coefficient of silicone hydrogel materials was tested according to ISO 18369-4:2017. The instrument used was an oxygen permeability meter with a sample thickness of 0.1 mm and a temperature of 35±0.5°C. The rate at which oxygen passes through the material was measured and the Dk value was calculated. Test the moisture content of silicone hydrogel materials. The test standard refers to ISO 10339:1997. The biocompatibility of the silicone hydrogel material was tested according to ISO 10993-5:2009. The material was immersed in PBS containing 1 mg / mL lysozyme and incubated at 37°C for 24 hours. The amount of adsorbed protein was determined by the CA method. The phase separation size of the silicone hydrogel material was tested and measured using a small-angle X-ray scattering instrument to calculate the phase separation size.

[0035] The results of the performance test of the contact lens silicone hydrogel materials prepared in Examples 1-5 and Comparative Examples 1-5 are shown in Table 1: Table 1

[0036] As shown in Table 1, the contact lens silicone hydrogel material prepared by the present invention exhibits high oxygen permeability, high water content, low modulus, high elongation at break, and low protein adsorption. In the first stage, during the preparation of prepolymer A, cationic ring opening is selectively activated, preserving the activity of vinyl and epoxy groups. In the second stage, free radical polymerization and epoxy ring opening are triggered to prevent side reactions. The residual epoxy groups in prepolymer A undergo a ring-opening reaction with the amide groups in mixture B in the second stage, forming ether bonds. The ether bonds generated by the epoxy ring opening connect the phase interfaces, achieving molecular-level bonding between the siloxane phase and the aqueous phase, inhibiting phase separation. Furthermore, the introduced ether bonds, due to their high flexibility, reduce the rigidity of the crosslinked network and the modulus of the material. In combination with a flexible segment modifier, the introduction of long-chain siloxane enhances molecular chain flexibility. The epoxy-containing cyclosiloxane monomer provides a continuous siloxane phase, ensuring oxygen pathways. The nanoscale phase separation ensures uniform dispersion of the hydrophilic and hydrophobic phases, preventing phase separation from blocking oxygen permeation pathways.

[0037] In Comparative Example 1, since the epoxy-containing cyclosiloxane monomer is replaced with the epoxy-free cyclosiloxane monomer 1,3,5,7-tetramethylcyclotetrasiloxane, the epoxy-amide ring-opening reaction is missing and a flexible ether bond interface cannot be formed; the phase separation size increases, resulting in a significant decrease in the performance of the silicone hydrogel material. In Comparative Example 2, the epoxy groups in prepolymer A were completely converted, and no epoxy groups remained in prepolymer A, which lost the second-stage interfacial bridging ability, resulting in a significant decrease in the performance of the silicone hydrogel material. Comparative Example 3 does not add a flexible chain segment regulator, the crosslinking network lacks long-chain siloxane flexible units, and the molecular chain movement ability is limited, resulting in a decrease in the elongation at break of the silicone hydrogel material; Comparative Example 4 only replaces “polyethylene glycol dimethacrylate” with “the same mass of ethylene glycol dimethacrylate”, and the short-chain crosslinking agent (Mn = 194 Da) leads to an excessively high crosslinking density, compression of the hydrophilic phase space, weakening of the PEG chain hydrophilic effect, and a decrease in the modulus, elongation at break, oxygen permeability, and water content of the silicone hydrogel material; Comparative Example 5 cancels the preparation of Prepolymer A and directly mixes all monomers; only a single UV light irradiation (385 nm, 30 mW / cm², 30 min) is performed, cationic and free radical polymerization competition side reactions are carried out, the network regularity is destroyed; the epoxy group is not oriented ring opening, the interface chemical bridge effect is poor, and the performance of the silicone hydrogel material is significantly decreased.

[0038] It should be understood by those of ordinary skill in the art that the above discussion of any of the embodiments is merely exemplary and is not intended to suggest that the scope of the present application is limited to these examples; under the idea of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above. In order to be brief, they are not provided in detail.

[0039] The present application is intended to cover all such alternatives, modifications, and variations as fall within the broad scope of the appended claims. Accordingly, any and all such modifications, variations, and equivalents that fall within the spirit and scope of the present application are intended to be included within the scope of the claims.

Claims

1. A method for preparing a contact lens silicone hydrogel material with good flexibility, characterized in that: The method comprises the following preparation steps: Step S1: mixing an epoxy-containing cyclosiloxane monomer, a hydroxyl-containing hydrophilic vinyl monomer, a flexible segment modifier, a silicon-containing crosslinking agent, and a cationic photoinitiator, and performing a first-stage cationic ring-opening polymerization under UV light with a wavelength of 350-370 nm, controlling the reaction degree so that the epoxy group conversion rate is ≤60%, to obtain a prepolymer A containing unreacted epoxy groups and vinyl groups; Step S2: mixing an amide group-containing hydrophilic monomer, a free radical crosslinking agent, and a free radical photothermal initiator to obtain a mixture B; Step S3: The prepolymer A and the mixture B are thoroughly mixed, bubbles are removed, and the mixture is irradiated under UV light with a wavelength of 380-410 nm for 15-20 minutes to carry out a second stage polymerization reaction. The mixture is heated to 50° C.-60° C. and reacted for 20-30 minutes to obtain a contact lens silicone hydrogel material.

2. The method for preparing a flexible contact lens silicone hydrogel material according to claim 1, wherein: The epoxy-containing cyclosiloxane monomer is 1,3,5,7-tetramethyl-3-(2,3-epoxypropoxypropyl)cyclotetrasiloxane or 1,3,5,7-tetramethyl-3-(4-epoxycyclohexyl)cyclotetrasiloxane.

3. The method for preparing a flexible contact lens silicone hydrogel material according to claim 1, wherein: The hydroxyl-containing hydrophilic vinyl monomer is 2-hydroxyethyl methacrylate or glycerol methacrylate.

4. The method for preparing a flexible contact lens silicone hydrogel material according to claim 1, wherein: The flexible segment regulator is methacryloxy polysiloxane.

5. The method for preparing a flexible contact lens silicone hydrogel material according to claim 1, wherein: The silicon-containing crosslinking agent is tetramethyldisiloxane dimethacrylate.

6. The method for preparing a flexible contact lens silicone hydrogel material according to claim 1, wherein: The cationic photoinitiator is bis(4-tert-butylbenzene)iodine hexafluorophosphate.

7. The method for preparing a flexible contact lens silicone hydrogel material according to claim 1, wherein: The prepolymer A is controlled so that the epoxy conversion rate is 40%-50% and the Mn is 2500-4000 Da.

8. The method for preparing a flexible contact lens silicone hydrogel material according to claim 1, wherein: The hydrophilic monomer containing an amide group is N-vinyl pyrrolidone or N,N-dimethylacrylamide, and the free radical photothermal initiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone.

9. The method for preparing a flexible contact lens silicone hydrogel material according to claim 1, wherein: The free radical crosslinking agent is polyethylene glycol dimethacrylate with an Mn of 400-600 Da.

10. A silicone hydrogel material for contact lenses with good flexibility, characterized by: The silicone hydrogel material for contact lenses with good flexibility is prepared by the preparation method of any one of claims 1 to 9.

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