High-refraction yellowing-resistant phenyl sulfide organic silicon material and preparation method thereof

Abstract

The invention discloses a high-refraction yellowing-resistant phenyl sulfide organic silicon material and a preparation method thereof, and belongs to the technical field of organic silicon materials. The high-refraction and yellowing-resistant phenyl sulfide organic silicon material comprises a phenyl sulfide modification unit, a siloxane component and a light stabilizer, the phenyl sulfide modified unit contains a biphenyl structure, the content of the biphenyl unit is 10-30 mol%, and the molar ratio of a phenyl sulfide chain segment to a phenyl siloxane chain segment is 1: 1.5-1: 5; the phenyl / methyl molar ratio in the siloxane component is in gradient change and is reduced to 1: 4 from initial 3: 2, that is, the phenyl ratio is reduced to 15% from 75%; the light stabilizer is a hindered amine-benzotriazole composite system, and the use amount of the light stabilizer is 0.5-1.2 wt% of the total weight of the material. The biphenyl is introduced into a phenyl sulfide chain segment, the conjugated electron cloud density of the biphenyl structure is high, and the refractive index of the material can be further improved and reaches 1.65 or above. The biphenyl structure absorbs ultraviolet energy and dissipates through intramolecular vibration, has the capability of capturing free radicals, and can remarkably improve the yellowing resistance of the material when being combined with the light stabilizer for use.

Description

Technical Field

[0001] This invention relates to the field of organosilicon materials technology, and more specifically, to a high-refractive-index, yellowing-resistant phenyl sulfide organosilicon material and its preparation method. Background Technology

[0002] Traditional organosilicon materials are difficult to meet the high refractive index (>1.60) requirements of high-end optical materials (such as LED packaging and optical coatings). The introduction of phenyl groups can significantly improve the refractive index of organosilicon materials. Typically, the refractive index of high-phenyl organosilicon materials is between 1.54 and 1.58. For example, the existing patent CN103588973A discloses a high-refractive-index phenyl silicone oil and its preparation method. By introducing a high proportion of phenyl groups (such as diphenylsiloxane repeating units), the refractive index is improved, and the refractive index of the silicone oil is between 1.56 and 1.58.

[0003] When thioethers act synergistically with other high-refractive-index groups, the refractive index is significantly improved, reaching over 1.65. Patent CN102015837B discloses a method for preparing high-refractive-index materials via a thiol-olefin addition reaction. The core of this method involves reacting polythiols (such as 3,3′-thiobis[2-[(2-mercaptoethyl)thio]-1-propanethiol, trimethylolpropane tris(2-mercaptoacetate), etc.) with alkenylsilanes (such as vinyltrimethoxysilane) through UV radiation or thermal initiation to form polysulfide polysilanes with thioether-related structures. The bulk material formed after hydrolysis and concentration of this type of polysulfide polysilane can have a refractive index ≥1.63, and the coating formed by combining it with high-refractive-index nanoparticles can achieve a refractive index of 1.59~1.67 (adjustable). However, this patent does not disclose data on the material's resistance to yellowing, and the coating performance depends on the addition of nanoparticles; the improvement in refractive index of purely organic-inorganic hybrid substrates remains limited.

[0004] The refractive index of high-phenyl silicone materials ranges from 1.54 to 1.58, which is insufficient to meet the high refractive index (>1.60) requirements of high-end optical materials (such as LED packaging and optical coatings). Introducing sulfides can raise the refractive index to 1.60–1.70, but the sulfide groups (R—S—R') are easily oxidized under the influence of oxygen, light, or heat, gradually forming oxysulfoxides (—SO—) and sulfones (—SO—). These products have stronger light absorption, causing the material to yellow. Simultaneously, ultraviolet light can directly break the C—S bonds of the sulfide or excite oxygen molecules, initiating free radical reactions to generate peroxides, which further decompose into chromophores (such as quinone structures). Direct polycondensation of phenyl sulfides with diphenylsilanediol leads to phase separation, reducing light transmittance and limiting the material's applications.

[0005] In view of this, we propose a high-refractive-index, yellowing-resistant phenyl sulfide organosilicon material and its preparation method. Summary of the Invention

[0006] The purpose of this invention is to provide a high-refractive-index, yellowing-resistant phenyl sulfide organosilicon material and its preparation method, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A high-refractive-index, yellowing-resistant phenyl sulfide organosilicon material comprises a phenyl sulfide modification unit, a siloxane component, and a light stabilizer. The phenyl sulfide modification unit contains a biphenyl structure, with a biphenyl unit content of 10-30 mol%, and the molar ratio of phenyl sulfide segments to phenylsiloxane segments is 1:1.5 to 1:5. The phenyl / methyl molar ratio in the siloxane component exhibits a gradient change, decreasing from an initial 3:2 to 1:4, i.e., the phenyl proportion decreases from 75% to 15%. The light stabilizer is a hindered amine-benzotriazole composite system, and its dosage is 0.5-1.2 wt% of the total weight of the material; the refractive index of this high-refractive-index, yellowing-resistant phenyl sulfide silicone material is ≥1.65, the yellowing resistance index ΔYI (500h UV) is ≤1, and the light transmittance is ≥90%.

[0008] Preferably, the biphenyl unit content is 15-25 mol%.

[0009] Preferably, the molar ratio of the phenyl sulfide segment to the phenylsiloxane segment is 1:2 to 1:4.

[0010] Preferably, the amount of light stabilizer is 0.8-1.0 wt% of the total weight of the material.

[0011] Preferably, it also contains titanate catalyst residue, the amount of titanate catalyst being 0.01-0.05% of the total weight of siloxane.

[0012] Preferably, the amount of titanate catalyst used is 0.02-0.04% of the total weight of siloxane.

[0013] A method for preparing the above-mentioned high-refractive-index, yellowing-resistant phenyl sulfide organosilicon material includes the following steps: Step 1: 4,4'-dichlorodiphenyl sulfide and 4,4'-biphenyl dithiophenol are subjected to a polycondensation reaction to obtain a prepolymer; Step 2: Phenylsiloxane and methylsiloxane are added in a gradient to the prepolymer obtained in Step 1, and the phenyl / methyl molar ratio is controlled to decrease from the initial 3:2 to 1:4. Step 3: Under vacuum conditions of 0.02-0.05 MPa, the material is cured and molded at 160±5℃ to obtain the target material.

[0014] Preferably, the temperature of the polycondensation reaction in step 1 is 80±5℃.

[0015] Preferably, when adding the siloxane component in step 2, the hindered amine-benzotriazole composite light stabilizer is added simultaneously. In step 2, a titanate catalyst is also added, with the amount of titanate catalyst being 0.01-0.05% of the total weight of the siloxane.

[0016] Preferably, the amount of titanate catalyst used is 0.02-0.04% of the total weight of siloxane.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention introduces biphenyl into the phenyl sulfide chain segment. The high conjugated electron cloud density of the biphenyl structure can further increase the refractive index of the material to above 1.65. After absorbing ultraviolet energy, the biphenyl structure dissipates through intramolecular vibrations and has the ability to capture free radicals. When used in conjunction with light stabilizers, it can significantly improve the material's resistance to yellowing. By gradient-controlled phenyl content, the high refractive index and low ultraviolet absorption / yellowing resistance in the phenyl sulfide organosilicon material are synergistically optimized, while the compatibility of the chain segments is greatly improved and phase separation is significantly reduced. Using a high phenyl content in the siloxane chain segment near the phenyl sulfide end can reduce interfacial light scattering and suppress phase separation at high temperatures, while using a low phenyl content in the siloxane chain segment at the far end weakens the material's absorption in the UV band and also improves the material's flexibility. The phenyl content decreases from high to low, reducing the interfacial energy between the phenylsiloxane (hydrophobic) and phenyl sulfide (polar) chain segments, effectively suppressing phase separation, thereby ensuring that the material has high light transmittance. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0019] Example: A high-refractive-index, yellowing-resistant phenyl sulfide organosilicon material comprises a phenyl sulfide modification unit, a siloxane component, and a light stabilizer. The phenyl sulfide modification unit contains a biphenyl structure, with a biphenyl unit content of 10-30 mol%, and the molar ratio of phenyl sulfide segments to phenylsiloxane segments is 1:1.5 to 1:5. The phenyl / methyl molar ratio in the siloxane component exhibits a gradient change, decreasing from an initial 3:2 to 1:4, i.e., the phenyl proportion decreases from 75% to 15%. The light stabilizer is a hindered amine-benzotriazole composite system, and its dosage is 0.5-1.2 wt% of the total weight of the material; the refractive index of this high-refractive-index, yellowing-resistant phenyl sulfide silicone material is ≥1.65, the yellowing resistance index ΔYI (500h UV) is ≤1, and the light transmittance is ≥90%.

[0020] Specifically, the biphenyl structure (containing a strongly conjugated system) is introduced into the phenyl sulfide modification unit. This not only improves the refractive index (≥1.65) through the synergistic effect of sulfur atoms and biphenyl rings, but also inhibits yellowing by utilizing the UV absorption capacity of the biphenyl rings. The phenyl / methyl molar ratio in the siloxane component is gradually reduced from 3:2 to 1:4, which not only ensures the overall high refractive index of the material (contributed by the high phenyl content), but also reduces the UV-sensitive sites by decreasing the phenyl content in the later stage. Combined with a light stabilizer, the yellowing resistance index is further controlled at ΔYI≤1. The transmittance of ≥90% proves that there is no obvious phase separation in the material, indicating that the phenyl sulfide segment and the siloxane segment have good compatibility, thus solving the technical problem of "increased refractive index accompanied by decreased transmittance" in traditional high-refractive organosilicon materials.

[0021] In this application, the content of biphenyl units is 15-25 mol.

[0022] Specifically, compared to the wider range of 10-30 mol%, the preferred range of 15-25 mol% has the following advantages: Superior performance: When the biphenyl unit content is ≥15mol%, sufficient density of the conjugated system can be ensured, the refractive index is significantly improved (stable ≥1.67), and the UV absorption capacity is sufficient, with the yellowing resistance index controllable between 0.5 and 0.8; Better processability: The content ≤25mol% can avoid the increase in material brittleness caused by excessive rigidity of the chain segments, maintaining the inherent flexibility and moldability of organosilicon materials, making it suitable for the fabrication of complex shaped devices; Better compatibility: This range can reduce the risk of phase separation caused by the aggregation of biphenyl units, ensuring that the transmittance is stable at over 92%, solving the problem of decreased material transmittance under high biphenyl content.

[0023] In this application, the molar ratio of the phenyl sulfide segment to the phenylsiloxane segment is 1:2 to 1:4.

[0024] Specifically, this optimal ratio achieves the following effects by precisely controlling the contributions of the two types of chain segments: Stable refractive index: The lower limit of 1:2 ensures that the high refractive contribution of the phenyl sulfide segment is not diluted, and the refractive index is not lower than 1.66; the upper limit of 1:4 can avoid the increase in yellowing sensitivity caused by the auxiliary refractive enhancement effect of the phenylsiloxane segment through the high proportion of the single phenyl sulfide segment; Synergistic enhancement of yellowing resistance: The introduction of the phenylsiloxane segment can dilute the sulfur atom density of the phenyl sulfide segment (sulfur atoms are easily oxidized and cause yellowing), and in combination with the biphenyl structure and light stabilizer, the yellowing resistance is improved compared with the 1:1.5 ratio; Improved interfacial compatibility: At this ratio, the polarity of the two types of segments is more matched, which can reduce interfacial stress and improve the mechanical properties of the material (such as tensile strength) compared with the 1:5 ratio.

[0025] In this application, the amount of light stabilizer is 0.8-1.0 wt% of the total weight of the material.

[0026] Specifically, the advantages of this preferred dosage are: Saturation of yellowing resistance: 0.8wt% or higher ensures that the light stabilizer (hindered amine-benzotriazole composite system) fully captures free radicals generated by UV aging, forming a dual protection of "UV absorption-free radical scavenging" with the biphenyl structure. After 500h UV aging, ΔYI remains stable at ≤0.7. No side effects: Below 1.0wt% avoids precipitation (affecting transmittance) or incompatibility with siloxane segments caused by excessive light stabilizer. Transmittance remains ≥92% without increasing material costs. Long-term stability: At this dosage, the migration rate of the light stabilizer is lower, and the material can still maintain ΔYI≤1.2 after long-term use (e.g., 1000h), solving the problem of rapid consumption of light stabilizer at low dosages.

[0027] This application also contains residual titanate catalyst, the amount of which is 0.01-0.05% of the total weight of siloxane.

[0028] Specifically, a dosage of ≥0.01% can ensure the complete polycondensation / crosslinking reaction of siloxane segments (conversion rate ≥98%), avoiding the decrease in refractive index or deterioration of yellowing resistance caused by unreacted monomer residues; a dosage of ≤0.05% can reduce the risk of metal ion catalytic oxidation caused by titanate catalyst residues (metal ions easily accelerate the aging of thioether bonds), thus reducing ΔYI compared to a dosage of 0.06%.

[0029] In this application, the amount of titanate catalyst used is 0.02-0.04% of the total weight of siloxane.

[0030] Specifically, 0.02-0.04% can achieve a siloxane conversion rate of ≥99%, while the residual catalyst concentration is extremely low (≤50ppm), ensuring stable material performance and avoiding the negative impact of metal ions on yellowing resistance. Within this dosage range, the reaction rate fluctuation is ≤5%, solving the problem of large performance differences between different batches of materials under a wide dosage range, making it suitable for industrial mass production. Compared to 0.05%, dosages below 0.04% can reduce catalyst consumption, lower production costs, and do not affect performance.

[0031] A method for preparing the above-mentioned high-refractive-index, yellowing-resistant phenyl sulfide organosilicon material includes the following steps: Step 1: 4,4'-dichlorodiphenyl sulfide and 4,4'-biphenyl dithiophenol are subjected to a polycondensation reaction to obtain a prepolymer; Step 2: Phenylsiloxane and methylsiloxane are added in a gradient to the prepolymer obtained in Step 1, and the phenyl / methyl molar ratio is controlled to decrease from the initial 3:2 to 1:4. Step 3: Under vacuum conditions of 0.02-0.05 MPa, the material is cured and molded at 160±5℃ to obtain the target material.

[0032] Specifically, step one involves the directional introduction of biphenyl structures through polycondensation to ensure the precise synthesis of phenyl sulfide modification units; step two uses a gradient feeding method to precisely control the gradual change of the phenyl / methyl ratio, avoiding uneven distribution caused by a single feeding; step three involves vacuum curing (0.02-0.05 MPa) to eliminate air bubbles inside the material (avoiding a decrease in light transmittance), and a temperature of 160±5℃ to ensure complete crosslinking without inducing thermal aging (sulfide bonds are easily oxidized at high temperatures).

[0033] In this application, the temperature of the polycondensation reaction in step 1 is 80±5℃.

[0034] Specifically, around 80℃ is the optimal temperature for the polycondensation of 4,4'-dichlorodiphenyl sulfide and 4,4'-biphenyl dithiophenol. The reaction rate is fast (completed in 3-4 hours) and byproducts (such as HCl) are easily removed, resulting in a prepolymer purity of ≥99%. Temperatures ≤85℃ can prevent the biphenyl structure from oxidizing or degrading at high temperatures, ensuring the retention of the effective conjugated structure in the prepolymer (directly affecting the refractive index and yellowing resistance of the final material). Compared to higher temperatures (such as 100℃), 80±5℃ can reduce energy consumption and decrease the time cost of the cooling process.

[0035] In this application, when adding the siloxane component in step 2, the hindered amine-benzotriazole composite light stabilizer is added simultaneously. Specifically, the simultaneous addition of the light stabilizer and siloxane can achieve uniform dispersion through the fluidity of the siloxane, avoiding excessively high local concentrations caused by later addition (which would lead to light stabilizer agglomeration and affect light transmittance).

[0036] In step 2, a titanate catalyst is also added, with the amount of titanate catalyst being 0.01-0.05% of the total weight of the siloxane.

[0037] Specifically, the simultaneous addition of catalyst and siloxane can immediately initiate the polycondensation reaction, ensuring that each batch of siloxane can fully react during the gradient feeding process and avoiding the accumulation of unreacted monomers; the correspondence between catalyst dosage and material residue (0.01-0.05%) can ensure that the performance fluctuation of different batches of materials is ≤3%, solving the problem of unstable performance during the preparation process.

[0038] In this application, the amount of titanate catalyst used is 0.02-0.04% of the total weight of siloxane.

[0039] Specifically, the dosage of 0.02-0.04% during the preparation process is completely matched with the residual amount in the final material, ensuring the consistency of "process parameters-material composition-performance indicators" and facilitating quality control; at this dosage, the crosslinking degree difference of each batch of siloxane is ≤2%, and the mechanical properties of the material, such as hardness and elasticity, are more stable.

[0040] Example 1: Preparation and performance testing of a high-refractive-index, yellowing-resistant phenyl sulfide organosilicon material 1.1 The raw materials and quantities are shown in Table 1 below; Table 1. Raw materials and dosages for Example 1

[0041] Note: The calculated content of biphenyl unit is 15 mol%, the molar ratio of phenyl sulfide segment to phenylsiloxane segment is 1:2, the amount of light stabilizer is 0.8 wt% of the total weight of the material, and the amount of catalyst is 0.03 wt% of the total weight of siloxane.

[0042] 1.2 Preparation steps Prepolymer synthesis: 4,4'-dichlorodiphenyl sulfide and 4,4'-biphenyl dithiophenol were added to a three-necked flask equipped with a stirrer, thermometer and reflux condenser. The temperature was raised to 80°C and stirred under nitrogen protection to carry out polycondensation reaction. The reaction lasted for 3 hours to obtain a light yellow viscous prepolymer.

[0043] Gradient addition of siloxanes and auxiliaries: Maintaining the reaction system temperature at 80℃, add a mixture of phenyltriethoxysilane and dimethyldimethoxysilane to the prepolymer in three gradients: The first addition is 1 / 3 of the total volume of the mixture, at which point the phenyl / methyl molar ratio is 3:2; Add the second mixture (1 / 3 of the total volume) after an interval of 1 hour, and adjust the phenyl / methyl molar ratio to 1:1; Add the third mixture (1 / 3 of the total volume) after 1 hour, and adjust the phenyl / methyl molar ratio to 1:4.

[0044] While adding siloxane, simultaneously add hindered amine 770-benzotriazole UV-327 composite light stabilizer and tetrabutyl titanate, and continue stirring until the system is homogeneous.

[0045] Curing and molding: The above mixture is transferred to a polytetrafluoroethylene mold, placed in a vacuum drying oven, heated to 160°C under a vacuum of 0.03 MPa, and cured for 4 hours. It is then naturally cooled to room temperature to obtain a high-refractive-index, yellowing-resistant phenyl sulfide silicone material.

[0046] 1.3 Performance Test Results Performance testing was conducted according to national standards and industry practice methods. Refractive index (25℃, 589nm): 1.67 (measured using an Abbe refractometer); Yellowing resistance index ΔYI (500h UV): 0.7 (measured by a colorimeter after aging in a UV aging test chamber). Transmittance (400-800nm): 92% (measured using a UV-Vis spectrophotometer).

[0047] Example 2: Preparation and performance testing of a high-refractive-index, yellowing-resistant phenyl sulfide organosilicon material 2.1 The raw materials and quantities are shown in Table 2 below; Table 2. Raw materials and dosages for Example 2

[0048] Note: The calculated content of biphenyl unit is 25 mol%, the molar ratio of phenyl sulfide segment to phenylsiloxane segment is 1:4, the amount of light stabilizer is 1.0 wt% of the total weight of the material, and the amount of catalyst is 0.04 wt% of the total weight of siloxane.

[0049] 2.2 Preparation steps Prepolymer synthesis: Same as in Example 1, 4,4'-dichlorodiphenyl sulfide and 4,4'-biphenyl dithiophenol were subjected to polycondensation reaction at 85°C for 3.5 h to obtain the prepolymer.

[0050] Gradient addition of siloxanes and additives: The gradient addition method is the same as in Example 1. The siloxane mixture is added in 3 batches, and the phenyl / methyl molar ratio is gradually reduced from 3:2 to 1:4. The light stabilizer and catalyst are added simultaneously and stirred evenly.

[0051] Curing and molding: Under a vacuum of 0.05 MPa, the material was cured at 165°C for 3.5 h and then cooled to obtain the target material.

[0052] 2.3 Performance Test Results Refractive index (25℃, 589nm): 1.69; Yellowing resistance index ΔYI (500h UV): 0.5; Light transmittance (400-800nm): 93%.

[0053] Example 3: Preparation and Performance Testing of a High-Refractive-Intensity, Yellowing-Resistant Benzene Sulfide Organosilicon Material 3.1 The raw materials and dosages are shown in Table 3 below; Table 3. Raw materials and dosages for Example 3

[0054] Note: The calculated content of biphenyl unit is 10 mol%, the molar ratio of phenyl sulfide segment to phenylsiloxane segment is 1:1.5, the amount of light stabilizer is 0.5 wt% of the total weight of the material, and the amount of catalyst is 0.02 wt% of the total weight of siloxane.

[0055] 3.2 Preparation steps Prepolymer synthesis: Same as in Example 1, 4,4'-dichlorodiphenyl sulfide and 4,4'-biphenyl dithiophenol were subjected to polycondensation reaction at 75°C for 2.5 h to obtain the prepolymer.

[0056] Gradient addition of siloxanes and additives: The gradient addition method is the same as in Example 1. The siloxane mixture is added in 3 batches, and the phenyl / methyl molar ratio is gradually reduced from 3:2 to 1:4. The light stabilizer and catalyst are added simultaneously and stirred evenly.

[0057] Curing and molding: Under a vacuum of 0.02 MPa, the material was cured at 155°C for 4.5 h and then cooled to obtain the target material.

[0058] 3.3 Performance Test Results Refractive index (25℃, 589nm): 1.65; Yellowing resistance index ΔYI (500h UV): 1.0; Light transmittance (400-800nm): 90%.

[0059] Comparative Example 1: Benzene sulfide organosilicon material without biphenyl structure and with non-gradient control of phenyl content 1.1 The raw materials and quantities are shown in Table 4 below; Table 4 Comparative Example 1: Raw Materials and Usage

[0060] Note: The phenyl / methyl molar ratio is fixed at 1:1 (non-gradient control), and there is no biphenyl unit.

[0061] 1.2 Preparation steps Prepolymer synthesis: 4,4'-dichlorodiphenyl sulfide and thiophenol were polycondensed at 80°C for 3 h to obtain the prepolymer.

[0062] Add siloxane and additives: Add a mixture of phenyltriethoxysilane and dimethyldimethoxysilane (phenyl / methyl molar ratio 1:1) at one time, and add light stabilizer and catalyst simultaneously, and stir evenly.

[0063] Curing and molding: Same curing conditions as in Example 1.

[0064] 1.3 Performance Test Results Refractive index (25℃, 589nm): 1.60; Yellowing resistance index ΔYI (500h UV): 6.2; Light transmittance (400-800nm): 82%.

[0065] Summary of Implementation Examples As can be seen from Examples 1-3 above, the present invention, by introducing a biphenyl structure into the phenyl sulfide chain segment, gradient controlling the phenyl / methyl molar ratio in the siloxane component, and combining it with a specific light stabilizer and catalyst system, has prepared phenyl sulfide organosilicon materials that have achieved excellent performance with a refractive index ≥1.65, a yellowing resistance index ΔYI (500h UV) ≤1, and a light transmittance ≥90%, which fully meets the application requirements of optoelectronic fields such as LED packaging and optical lenses.

[0066] As can be seen from Comparative Example 1, when the biphenyl structure is missing or the phenyl content is not controlled by gradient, the refractive index of the material decreases significantly, the yellowing resistance deteriorates drastically, and the transmittance decreases. This fully demonstrates that the key technical features of this invention (introduction of biphenyl units, gradient phenyl control, etc.) play a decisive role in solving the technical problem of "difficulty in balancing high refractive index and yellowing resistance".

[0067] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-refractive-index, yellowing-resistant phenyl sulfide organosilicon material, characterized in that, The product comprises a phenyl sulfide modification unit, a siloxane component, and a light stabilizer; the phenyl sulfide modification unit contains a biphenyl structure, the biphenyl unit content is 10-30 mol%, and the molar ratio of phenyl sulfide segment to phenyl siloxane segment is 1:1.5 to 1:5; the phenyl / methyl molar ratio in the siloxane component changes in a gradient, from an initial 3:2 to 1:4, that is, the phenyl proportion decreases from 75% to 15%; The light stabilizer is a hindered amine-benzotriazole composite system, and its dosage is 0.5-1.2 wt% of the total weight of the material; the refractive index of the high-refractive-index, yellowing-resistant phenyl sulfide silicone material is ≥1.65, the yellowing resistance index ΔYI (500h UV) is ≤1, and the light transmittance is ≥90%.

2. The high refractive index and yellowing-resistant phenyl sulfide organosilicon material according to claim 1, characterized in that: The content of the biphenyl unit is 15-25 mol.

3. The high refractive index and yellowing-resistant phenyl sulfide organosilicon material according to claim 1, characterized in that: The molar ratio of the phenyl sulfide segment to the phenylsiloxane segment is 1:2 to 1:

4.

4. The high refractive index and yellowing-resistant phenyl sulfide organosilicon material according to claim 1, characterized in that: The amount of light stabilizer used is 0.8-1.0 wt% of the total weight of the material.

5. The high refractive index and yellowing-resistant phenyl sulfide organosilicon material according to claim 1, characterized in that: It also contains residual titanate catalyst, the amount of which is 0.01-0.05% of the total weight of siloxane.

6. The high refractive index and yellowing-resistant phenyl sulfide organosilicon material according to claim 1, characterized in that: The titanate catalyst is used in an amount of 0.02-0.04% of the total weight of the siloxane.

7. A method for preparing any of the high-refractive-index, yellowing-resistant phenyl sulfide organosilicon materials according to claims 1-6, characterized in that, Includes the following steps: Step 1: 4,4'-dichlorodiphenyl sulfide and 4,4'-biphenyl dithiophenol are subjected to a polycondensation reaction to obtain a prepolymer; Step 2: Phenylsiloxane and methylsiloxane are added in a gradient to the prepolymer obtained in Step 1, and the phenyl / methyl molar ratio is controlled to decrease from the initial 3:2 to 1:

4. Step 3: Under vacuum conditions of 0.02-0.05 MPa, the material is cured and molded at 160±5℃ to obtain the target material.

8. The method for preparing a high-refractive-index, yellowing-resistant phenyl sulfide organosilicon material according to claim 7, characterized in that: The temperature of the polycondensation reaction in step 1 is 80±5℃.

9. The method for preparing a high-refractive-index, yellowing-resistant phenyl sulfide organosilicon material according to claim 7, characterized in that: When adding the siloxane component in step 2, the hindered amine-benzotriazole complex light stabilizer is added simultaneously. Step 2 also involves adding a titanate catalyst, the amount of which is 0.01-0.05% of the total weight of the siloxane.

10. The method for preparing a high-refractive-index, yellowing-resistant phenyl sulfide organosilicon material according to claim 7, characterized in that: The titanate catalyst is used in an amount of 0.02-0.04% of the total weight of the siloxane.

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