A high-refractive-index thioether-type episulfide compound, its preparation method, and application

Abstract

A high-refractive-index thioether-type episulfide compound, its preparation method, and application. The compound has a structure shown in Formula I, Formula II, or Formula III. Its refractive index reaches 1.66 to 1.76. The compound or a mixture thereof can be in situ polymerized with an isothiocyanate or an isocyanate to prepare a high-refractive-index polyurethane optical material. The polyurethane optical material has the advantages of high refractive index and transmittance, low chroma, and strong overall performance. It can be used on a variety of different optical substrates, providing a wider range of material options for the application of high-end optical components. The preparation method of the present invention has a simple process, readily available raw materials, mild reaction conditions, and good controllability. (I) wherein R and R1 are the same or different and each is H, CH3, or C6H5; (II) and (III) wherein R is H or CH3.

Description

Technical Field

[0001] The invention belongs to the technical field of synthesis and preparation of polyurethane optical materials, and particularly relates to a high-refractive-index thioether-type episulfide compound and a preparation method and application thereof. Background Art

[0002] Lightweighting optical systems means minimizing the curvature, thickness, and weight of optical components while ensuring optical performance and functionality, enabling miniaturization, precision, and integration of optical devices. Improving the refractive index is a key means of achieving this lightweighting. Western developed countries, due to earlier research, are at the forefront of this field. For example, Mitsui Chemicals of Japan uses trivalent thiols with mercapto groups (-SH) instead of hydroxyl groups to react with isocyanates to produce high-refractive-index polyurethane resins (product code MR), with a refractive index ranging from 1.67 to 1.76. These products have long dominated the global market. U.S. Patent No. 2011046285 discloses the reaction of epoxy compounds with thiocyanates to produce high-refractive-index, high-epoxysulfide monomers.

[0003] The refractive index is inversely proportional to the molecular volume and directly proportional to the molar refractive index, which in turn is directly proportional to the polarizability of the medium. To increase the refractive index of a resin, the main approach is to introduce groups with high molar refractive index and small molecular volume into the polymer's molecular structure. High-refractive polyurethanes overcome the opacity of traditional polyurethanes, offering high transmittance, strength, and impact resistance. They are widely used in high-end optical applications such as optical lenses, instrument prisms, light filters, LED lighting, smart cars, and window materials. In recent years, there have been numerous reports on increasing the refractive index of thiol monomers through the introduction of sulfur atoms through molecular design. Because sulfur atoms have d-orbitals in their outer shells, their two pairs of electrons are easily polarized, resulting in both low molecular dispersion and a high molecular refractive index.

[0004] The following are some examples of methods for synthesizing high-sulfur compound monomers.

[0005] (1) Alkyl halides react with sodium hydrosulfide in an alcohol solution to produce thiols, as shown in formula (1). This method has a high reaction temperature. Sodium hydrosulfide is unstable at high temperatures and easily decomposes into Na2S. It also easily generates by-products, making the production process difficult to control.

[0006]

[0007] (2) Alkyl halide reacts with thioacid under certain conditions to form thiol ester. - or H + Under certain conditions, it is hydrolyzed to thiol, as shown in formula (2). However, this method has low yield and high cost, which is not conducive to industrial-scale production.

[0008]

[0009] (3) Mercaptoethanol reacts with trichloropropane, refluxes and reacts with a KOH solution containing ME, separates the liquids and refluxes under reduced pressure to obtain 1,2,3-mercaptoethylthiopropane. However, mercaptoethanol is easily oxidized under high temperature and alkaline conditions to generate complex by-products, which causes the mercaptan to turn yellow, affecting the use of the product.

[0010] (4) Using sulfur monochloride and mercaptoethanol as raw materials and petroleum ether as solvent, diethyl tetrasulfide is condensed to obtain isothiourea salt, which is then hydrolyzed to obtain tetrathio-based polythiol. This method is complex and has high production costs. In addition, the use of large amounts of toxic solvents is not conducive to environmental protection.

[0011] Thiol compounds synthesized through the aforementioned chemical reactions have achieved significant breakthroughs, including some employing episulfide compounds with higher sulfur contents to produce optical materials with higher refractive indices, some exceeding 1.85. However, the resulting episulfide monomers remain subject to low purity. Side reactions often occur during the synthesis process, resulting in products with low purity and unsuitable for use as optical materials. Traditional extraction and distillation methods alone are difficult to separate from complex mixtures. Alternatively, the synthesized monomers may be unstable, agglomerating or self-aggregating during storage, hindering their use in high-end optical components. Some also face challenges such as demanding synthesis conditions, making large-scale production difficult. Therefore, advanced synthetic methods and technologies will become increasingly important in the development and application of novel episulfide compounds. Summary of the Invention

[0012] To address the aforementioned issues in the prior art, the present invention provides a thioether-type episulfide compound having a refractive index of 1.66 to 1.76. This compound or a mixture thereof can be in-situ polymerized with an isothiocyanate or an isocyanate to prepare a high-refractive-index polyurethane optical material. This polyurethane optical material exhibits high refractive index and transmittance, low chroma, and excellent overall performance. It can be applied to a variety of different optical substrates, providing a wider range of material options for applications in high-end optical components.

[0013] To achieve the above object, the present invention provides the following technical solutions:

[0014] A high-refractive-index thioether-type episulfide compound, the structure of which is represented by Formula I, Formula II, or Formula III:

[0015]

[0016] (I)

[0017] Wherein R and R1 are the same or different and are each H, CH3 or C6H5;

[0018]

[0019] (II)

[0020]

[0021] (III)

[0022] Wherein R is H or CH3.

[0023] On the other hand, the present invention provides a method for preparing the high-refractive-index thioether-type episulfide compound I described above, the method comprising the following steps:

[0024] ⑴ Add 1,3-diphenylacetone and anhydrous ethanol in a weight ratio of (1-3): (3-7) to a reaction vessel, stir evenly, and introduce hydrogen sulfide and hydrogen chloride dry gases for 3-7 hours. The reaction temperature is controlled at 0-6°C. After 10-12 hours, vacuum dry the precipitate to obtain a thiol intermediate.

[0025] (2) The thiol intermediate, benzaldehyde and diethyl ether are fully mixed in a weight ratio of (1-2): (1-2): (100-150), and a catalyst is added thereto in an amount of 1 / 8-1 / 12 of the weight of the thiol intermediate. The reaction is stopped after being fully stirred at room temperature for 7-10 hours. A saturated sodium chloride solution is then added, and the mixture is stirred and separated into layers. The upper diethyl ether layer is taken out, dried, and decolorized with attapulgite adsorbent until it becomes colorless and transparent. The diethyl ether solvent is removed by distillation to obtain a viscous thioether-type tricyclic sulfide compound I.

[0026] In the above-mentioned method for preparing the high-refractive-index sulfide-type episulfide compound I, preferably, the catalyst is one of hydrochloric acid, sulfuric acid, toluenesulfonic acid, and p-toluenesulfonic acid.

[0027] In another aspect, the present invention provides a method for preparing the high-refractive-index thioether-type episulfide compound II, comprising the following steps:

[0028] ⑴ Add 1,3-diphenylacetone and anhydrous ethanol in a weight ratio of (1-3): (3-7) to a reaction vessel, stir evenly, and introduce hydrogen sulfide and hydrogen chloride dry gases for 3-7 hours. The reaction temperature is controlled at 0-6°C. After 10-12 hours, vacuum dry the precipitate to obtain a thiol intermediate.

[0029] ⑵ Add anhydrous ethanol and the thiol intermediate to the reaction vessel. After they are fully dissolved, add ferric chloride and water. The weight ratio of the thiol intermediate, ethanol, ferric chloride and water is (1-3): (2-5): (2-4): (2-3). Stir and react at 0-10°C for 4-6 hours. A white powdery substance precipitates. Filter to obtain a crude product, recrystallize it with n-hexane, and dry it in vacuo to obtain a thioether-type tetracyclic sulfur compound II.

[0030] In another aspect, the present invention provides a method for preparing the high-refractive index thioether-type episulfide compound III, comprising the following steps: adding sodium pentathiocarbonate to methanol, heating to 25-45° C. after complete dissolution, adding a dibromomethane methanol solution dropwise over 1.5-2.5 hours, and slowly stirring the mixture for about 30-35 hours; the weight ratio of sodium pentathiocarbonate, methanol, and dibromomethane methanol solution is (1-3):(2-5):(3-7), and the concentration of the dibromomethane methanol solution is 6-12 wt %; adding distilled water to the reaction system, extracting with chloroform, combining the extracts, and removing the chloroform by atmospheric distillation to obtain a colloidal thioether-type episulfide compound III.

[0031] Chloroform is selected as the extraction solvent in the extraction process mainly because the solvent has a high density and a low boiling point. The sodium bromide precipitate is dissolved and then removed with the water. The solvent can be quickly evaporated from the organic phase at normal pressure of 55-60°C, avoiding the generation of complex by-products of the episulfide compound monomer under high temperature conditions, which will cause the monomer to have a darker color and affect its use as an optical material.

[0032] In another aspect, the present invention provides the use of the high-refractive-index thioether-type episulfide compound as a polyurethane optical material, wherein the polyurethane optical material is polymerized with the high-refractive-index thioether-type episulfide compound and an isothiocyanate compound and / or an isocyanate compound.

[0033] In the application described above, preferably, the mass ratio of the high refractive index thioether-type episulfide compound to the isothiocyanate compound, the isocyanate compound or the mixture thereof is (30-70): (10-50).

[0034] The sodium pentathiocarbonate of the present invention can be purchased through commercial channels or prepared by the following method: sodium sulfide is dissolved in anhydrous ethanol, carbon disulfide is added thereto, and the mixture is stirred and reacted at room temperature. Sulphur is then added thereto with stirring, and microwave heating is controlled at 40-45°C for 20-60 minutes. The mixture is naturally cooled to room temperature, and an n-pentane solution is added to precipitate the sodium pentathiocarbonate. The use of low-density n-pentane during the reaction facilitates the precipitation of crystals.

[0035] The beneficial effects of the present invention are:

[0036] (1) The raw materials required in the reaction process of the method of the present invention are abundant in domestic sources and are easily purchased. The synthesis process is simple, the reaction conditions are mild and the controllability is good. There is no special customization requirement for the equipment required for production. Conventional equipment can meet the requirements of the synthesis process, which reduces the cost of application to a certain extent.

[0037] ⑵ The prepared thioether-type episulfide compounds have high purity, light color, and good homopolymerization and copolymerization properties. The highly cross-linked network formed during the polymerization process limits the crystallization of the groups, ensuring the high transparency of the polyurethane material.

[0038] (3) The polyurethane optical material polymerized from the thioether-type episulfide compound has the advantages of high transmittance, high refractive index and low chroma. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 FT-IR infrared spectrum of the tricyclic sulfide compound (i) prepared in a specific embodiment.

[0040] Figure 2 1 is the HNMR nuclear magnetic resonance hydrogen spectrum of the tricyclic sulfur compound (i) prepared in a specific embodiment.

[0041] Figure 3 FT-IR infrared spectrum of the tetracyclic sulfur compound (ii) prepared in a specific embodiment.

[0042] Figure 4 FT-IR infrared spectrum of the pentacyclic sulfur compound (iii) prepared in a specific embodiment.

[0043] Figure 5 FIG. 4 is a refractive index curve of a thioether-type episulfide compound prepared in a specific embodiment. DETAILED DESCRIPTION

[0044] The present invention will be further described below with reference to specific examples, which are not intended to limit the scope of protection of the present invention.

[0045] The thioether-type episulfide compounds in the following examples were prepared by the following method:

[0046] 1. Preparation of tricyclic sulfide compound (i):

[0047] The specific reaction formula is as follows:

[0048]

[0049] R, R1 are phenyl

[0050] 900 g of 1,3-diphenylacetone and 1680 g of anhydrous ethanol were added to a reaction vessel, stirred evenly, and then hydrogen sulfide and hydrogen chloride dry gases were introduced for 6 h. The reaction temperature was controlled at 2°C. After 10 h, the precipitate was vacuum dried to obtain a thiol intermediate. 240 g of the thiol intermediate and 150 g of benzaldehyde were added to 25,000 g of ether solvent, and 24 g of p-toluenesulfonic acid was added thereto. The mixture was stirred at room temperature for 9 h, and then a saturated sodium chloride solution was added. After stirring and separation, the upper light yellow ether layer was removed, dried, and decolorized with a 150-mesh attapulgite adsorbent until transparent. The ether solvent was evaporated to obtain 149 g of tricyclic sulfide compound (i) with a yield of 61.3%.

[0051] Infrared spectroscopy Figure 1 As shown, FT-IR (cm -1 ) analysis: positions 3060-3031 are the CH stretching vibrations of the benzene ring; positions 2902 are the saturated CH stretching vibrations; positions 1601-1492 are the C=C skeleton stretching vibrations of the benzene ring; positions 1489 are the CH2 scissor vibrations; positions 745-697 are the out-of-plane deformation vibrations of multiple adjacent H atoms =CH on the benzene ring and the ring skeleton deformation vibrations; positions 579 are the C-S stretching vibrations.

[0052] HNMR nuclear magnetic resonance spectroscopy Figure 2 As shown, 1 H NMR (δ) analysis: 7.32 (m, 20H, Ar-H), 2.72 (s, 4H, CH2), δ = 7.24 ~ 7.34 ppm, where δ = 7.32 ppm indicates the presence of 20 hydrogen atoms (Ar-H), which are located on the benzene ring and exhibit multiple peaks (m); δ = 4.57 ppm corresponds to a hydrogen atom attached to the sulfur heterocycle in the tricyclic sulfur compound molecule, which exhibits a single peak due to the absence of hydrogen atoms on adjacent carbon atoms; δ = 2.72 ppm indicates a single peak (s) due to the presence of four hydrogen atoms on the methylene group (CH2).

[0053] 2. Preparation of tetracyclic sulfur compound (ii):

[0054] The specific reaction formula is as follows:

[0055]

[0056] (ii)

[0057] 360 g of the thiol intermediate prepared in the above step was added to 1080 ml of ethanol, dissolved, and then 820 g of ferric chloride and 650 g of water were added, followed by repeated stirring. The temperature was controlled at 5°C and the reaction was carried out for 4.5 h. The collected precipitate was recrystallized from n-hexane and dried in vacuo to obtain 186 g of tetracyclic sulfur compound (ii) with a yield of 51.5%.

[0058] Infrared spectroscopy Figure 3 As shown, FT-IR (cm -1 ) analysis: positions 3055-3026 are the CH stretching vibrations of the benzene ring; positions 2909 are the saturated CH stretching vibrations; positions 1603-1556 are the C=C skeleton stretching vibrations of the benzene ring; positions 1490 are the C=C stretching vibrations of the benzene ring; positions 1450 are the CH2 scissor vibrations; positions 749-706 are the out-of-plane deformation vibrations of the five adjacent H atoms =CH on the benzene ring and the ring skeleton deformation vibrations; positions 587 are the CS stretching vibrations; and positions 508 are the SS stretching vibrations.

[0059] 1HNMR (δ): 7.37(m, 20H, Ar-H), 2.6(s, 8H, CH2).

[0060] 3. Preparation of pentacyclic sulfur compound (iii):

[0061] The specific reaction process is as follows:

[0062]

[0063] 2200 g of sodium sulfide was dissolved in 11000 g of anhydrous ethanol, and 2400 g of carbon disulfide was added. The mixture was stirred and reacted at room temperature. 160 g of sulfur was added with stirring, and the mixture was microwaved at 45°C for 50 min. The mixture was naturally cooled to room temperature, and n-pentane solvent was added to precipitate sodium pentathiocarbonate. 1050 g of sodium pentathiocarbonate was added to 2400 g of methanol, and after dissolution, the mixture was heated to 35°C, and 5200 g of an 8% dibromomethane methanol solution was added dropwise over 2 h. The mixture was stirred and reacted for 31 h. Distilled water was added, and the mixture was extracted with chloroform. The extracts were combined, dried over anhydrous sodium sulfate, and chloroform was removed by atmospheric distillation to obtain 318 g of pentacyclic sulfur compound (iii) with a yield of 45.4%.

[0064] Infrared spectroscopy Figure 4 As shown, FT-IR (cm -1 ) analysis: 2955~2887 is the CH stretching vibration peak, 1380~1183 is the CH2 non-planar swing absorption peak on the ring; 809~596 is the CS stretching vibration strong absorption peak; 460 is the SS weak vibration absorption peak.

[0065] 1 HNMR (δ) analysis: 4.30 (s, 4H, 2CH2), the compound has a single peak at δ = 4.30 ppm, indicating that the two CH2 are in the same chemical environment, indicating that the compound has a symmetrical structure.

[0066] Example 1: Preparation of polyurethane optical material containing tricyclic sulfide compound monomer (i)

[0067] ⑴ After heating 20 g of an isothiocyanate compound (Hunan Yunbang Biotechnology Co., Ltd., product number: YB06161, the same in the following examples) to 85°C, 15 g of xylene diisocyanate was added with stirring, and then 0.6 g of triethylenediamine was added and stirred to obtain a mixture.

[0068] (2) 65 g of the tricyclic sulfide compound (i) prepared above was added to the mixture prepared in step (1) above, 1.6 g of dibutyltin dilaurate was added to the reaction mixture, and the mixture was heated to 45°C and stirred for prepolymerization for 35 minutes. The bubbles were removed by vacuum and the mixture was injected into a lens mold;

[0069] ⑶ Place the mold containing the prepolymer in a curing oven at 45°C and heat for 3 hours, then gradually raise the temperature to 85°C and continue to place for 3 hours. Finally, cool to room temperature and demold to obtain a high-refractive polyurethane optical material.

[0070] Example 2: Preparation of polyurethane optical material containing tricyclic sulfide compound (i)

[0071] (1) Heat 20g of isothiocyanate compound to 65°C, add 5g of xylene diisocyanate with stirring, and then add 0.4g of triethylenediamine, and stir evenly to obtain a mixture.

[0072] (2) 30 g of the tricyclic sulfide compound (i) prepared above was added to the mixture prepared in step (1) above, 0.9 g of dibutyltin dilaurate was added to the reaction mixture, and the mixture was heated to 50°C and stirred for prepolymerization for 35 min. The bubbles were removed by vacuum and the mixture was injected into a lens mold;

[0073] ⑶ Place the mold containing the prepolymer in a curing oven at 45°C and heat for 3 hours, then gradually raise the temperature to 85°C and continue to place for 3 hours. Finally, cool to room temperature and demold to obtain a high-refractive polyurethane optical material.

[0074] Example 3: Preparation of polyurethane optical material containing tricyclic sulfide compound (i)

[0075] (1) 30 g of the tricyclic sulfide compound (i) prepared above was added to 19 g of xylene diisocyanate and stirred to obtain a reactant.

[0076] ⑵ Add 0.7 g of dibutyltin dilaurate to the reactant prepared in step (1) above, heat to 45°C, keep stirring and prepolymerize for 35 min, remove bubbles in vacuo, and inject into the lens mold;

[0077] ⑶ Place the mold containing the prepolymer in a curing oven at 45°C and heat for 3 hours, then gradually raise the temperature to 85°C and continue to place for 3 hours. Finally, cool to room temperature and demold to obtain a high-refractive polyurethane optical material.

[0078] Example 4: Preparation of polyurethane optical material containing tetracyclic sulfur compound (ii)

[0079] (1) Heat 12g of isothiocyanate compound to 85°C, add 15g of xylene diisocyanate with stirring, then add 0.2g of triethylenediamine, and stir evenly to obtain a mixture.

[0080] (2) 45 g of the tetracyclic sulfur compound (ii) prepared above was added to the mixture prepared in step (1) above, 1.1 g of dibutyltin dilaurate was added to the reaction mixture, and the mixture was heated to 45°C and stirred for prepolymerization for 35 min. The bubbles were removed by vacuum and the mixture was injected into a lens mold;

[0081] ⑶ Place the mold containing the prepolymer in a curing oven at 45°C and heat for 3 hours, then gradually raise the temperature to 85°C and continue to place for 3 hours. Finally, cool to room temperature and demold to obtain a high-refractive polyurethane optical material.

[0082] Example 5: Preparation of polyurethane optical material containing tetracyclic sulfur compound (ii)

[0083] (1) Heat 15g of isothiocyanate compound to 65°C, add 5g of xylene diisocyanate with stirring, and then add 0.4g of triethylenediamine, and stir evenly to obtain a mixture.

[0084] (2) 30 g of the tetracyclic sulfur compound (ii) prepared above was added to the mixture prepared in step (1) above, 0.9 g of dibutyltin dilaurate was added to the reaction mixture, and the mixture was heated to 50°C and stirred for prepolymerization for 35 min. The bubbles were removed by vacuum and the mixture was injected into a lens mold;

[0085] ⑶ Place the mold containing the prepolymer in a curing oven at 45°C and heat for 3 hours, then gradually raise the temperature to 85°C and continue to place for 3 hours. Finally, cool to room temperature and demold to obtain a high-refractive polyurethane optical material.

[0086] Example 6: Preparation of polyurethane optical material containing tetracyclic sulfur compound (ii)

[0087] (1) 45 g of the tetracyclic sulfur compound (ii) prepared above was added to 19 g of xylene diisocyanate and stirred to obtain a reactant;

[0088] ⑵ Add 0.7 g of dibutyltin dilaurate to the reactant prepared in step (1) above, heat to 45°C, keep stirring and prepolymerize for 35 min, remove bubbles in vacuo, and inject into the lens mold;

[0089] ⑶ Place the mold containing the prepolymer in a curing oven at 45°C and heat for 3 hours, then gradually raise the temperature to 85°C and continue to place for 3 hours. Finally, cool to room temperature and demold to obtain a high-refractive polyurethane optical material.

[0090] Example 7: Preparation of polyurethane optical material containing pentacyclic sulfur compound (iii)

[0091] (1) Heat 20g of isothiocyanate compound to 85°C, add 15g of xylene diisocyanate with stirring, then add 0.6g of triethylenediamine, and stir evenly to obtain a mixture;

[0092] (2) 65 g of the pentacyclic sulfur compound (iii) prepared above was added to the mixture prepared in step (1) above, 1.6 g of dibutyltin dilaurate was added to the reaction mixture, and the mixture was heated to 45°C and stirred for prepolymerization for 35 min. The bubbles were removed by vacuum and the mixture was injected into a lens mold;

[0093] ⑶ Place the mold containing the prepolymer in a curing oven at 45°C and heat for 3 hours, then gradually raise the temperature to 85°C and continue to place for 3 hours. Finally, cool to room temperature and demold to obtain a high-refractive polyurethane optical material.

[0094] Example 8: Preparation of polyurethane optical material containing pentacyclic sulfur compound (iii)

[0095] (1) After heating 30 g of the pentacyclic sulfur compound (iii) to 50°C, add 15 g of methanedithiol and stir evenly to obtain a mixture;

[0096] (2) Add the mixture prepared in step (1) above to 20 g of the isothiocyanate compound, add 0.6 g of triethylenediamine and 0.9 g of dibutyltin dilaurate to the reaction mixture, heat to 50°C, keep stirring and prepolymerize for 35 min, remove bubbles in vacuo, and inject into a lens mold;

[0097] ⑶ Place the mold containing the prepolymer in a curing oven at 45°C and heat for 3 hours, then gradually raise the temperature to 85°C and continue to place for 3 hours. Finally, cool to room temperature and demold to obtain a high-refractive polyurethane optical material.

[0098] Example 9: Preparation of polyurethane optical material containing pentacyclic sulfur compound (iii)

[0099] (1) 30 g of the pentacyclic sulfur compound (iii) prepared above was added to 20 g of xylene diisocyanate and stirred to obtain a reactant.

[0100] ⑵ Add 0.7 g of dibutyltin dilaurate to the reactant prepared in step (1) above, heat to 45°C, keep stirring and prepolymerize for 35 min, remove bubbles in vacuo, and inject into the lens mold;

[0101] ⑶ Place the mold containing the prepolymer in a curing oven at 45°C and heat for 3 hours, then gradually raise the temperature to 85°C and continue to place for 3 hours. Finally, cool to room temperature and demold to obtain a high-refractive polyurethane optical material.

[0102] Example 10: Preparation of polyurethane optical material containing pentacyclic sulfur compound (iii)

[0103] (1) After heating 30 g of the pentacyclic sulfur compound (iii) to 50°C, add 0.5 g of toluene solvent and stir evenly to obtain a mixture;

[0104] (2) After heating 20 g of the isothiocyanate compound to 75° C., 0.3 g of triethylenediamine was added thereto with stirring, and then the mixture prepared in step (1) was added thereto to obtain a reactant;

[0105] ⑶ Add 0.6g of dibutyltin dilaurate to the reactant prepared in step (2), heat to 50°C, keep stirring and prepolymerize for 35 minutes, remove bubbles in vacuo, and inject into the lens mold;

[0106] (4) Place the mold containing the prepolymer in a curing oven at 45°C and heat for 3 hours, then gradually increase the temperature to 85°C and continue to place for 3 hours. Finally, cool to room temperature and demould to obtain a high-refractive polyurethane optical material.

[0107] Example 11: Optical performance testing experiment on polyurethane optical materials

[0108] The optical properties of the polyurethane optical materials prepared in Examples 1-10 were tested respectively. Light transmittance is one of the most important properties of optical materials, which is expressed by transmittance. The test was performed using the UV-8000 UV-visible photometer of Shanghai Yuanxi Instrument Co., Ltd. The test method was: directly place the sample on the UV-visible photometer to measure the transmittance; the refractive index test was performed using the WZS1 Abbe refractometer of Shanghai Optical Instrument Equipment Co., Ltd. The test method was: ① dilute the sulfide-type episulfide compound prepared in the specific embodiment with ether solvent and apply it on the prism of the Abbe refractometer. After the solvent evaporates, record the test results; ② place the polyurethane optical material samples prepared in Examples 1-10 on the prism of the Abbe refractometer to measure the refractive index. The test results are shown in Figure 5 , Table 1, Table 2.

[0109] Table 1 Refractive index of test samples

[0110] Thioether-type episulfide compounds i ii iii Refractive index (nd) 1.663 1.712 1.760

[0111]

[0112] Example 12: Aging resistance test on polyurethane optical materials

[0113] The polyurethane optical materials prepared in Examples 1-10 were subjected to aging resistance tests. A water-cooled xenon lamp test chamber from Shanghai Diannuo Technology Co., Ltd. was used, and extreme lighting conditions were selected. The samples were irradiated in the aging resistance test chamber for 32 hours. The visible light spectral transmittance (tv) and yellowness index (IY) of the samples were tested before and after irradiation. The test results are shown in Table 3.

[0114]

[0115] Conclusion: Through data comparison, it is known that no significant changes occur in the samples tested in the embodiment.

Claims

1. Application of a high refractive index thioether-type episulfide compound as a polyurethane optical material, characterized in that: The polyurethane optical material is formed by polymerizing the high-refractive-index thioether-type episulfide compound and the isothiocyanate compound and / or the isocyanate compound; The structure of the compound is shown in Formula I or Formula II: Wherein R and R1 are the same or different and are each H, CH3 or C6H5; 2. The use according to claim 1, characterized in that The preparation method of the high refractive index thioether-type episulfide compound of formula (I) comprises the following steps: (1) 1,3-diphenylacetone and anhydrous ethanol are added to a reaction vessel in a weight ratio of (1-3): (3-7), stirred evenly, and hydrogen sulfide and hydrogen chloride dry gases are introduced successively for 3-7 hours. The reaction temperature is controlled at 0-6°C. After 10-12 hours, the precipitate is vacuum dried to obtain a thiol intermediate; (2) The thiol intermediate, benzaldehyde and diethyl ether are fully mixed in a weight ratio of (1-2): (1-2): (100-150), and a catalyst of 1 / 8-1 / 12 of the weight of the thiol intermediate is added thereto. The reaction is stopped after being fully stirred at room temperature for 7-10 hours. A saturated sodium chloride solution is then added, and after stirring and mixing to separate the layers, the upper diethyl ether layer is taken out, dried and decolorized with attapulgite adsorbent until it becomes colorless and transparent, and the diethyl ether solvent is distilled off to obtain a viscous thioether-type tricyclic sulfur compound of formula (I).

3. The use according to claim 2, characterized in that The catalyst is one of hydrochloric acid, sulfuric acid, toluenesulfonic acid and p-toluenesulfonic acid.

4. The use according to claim 1, wherein The preparation method of the high refractive index thioether-type episulfide compound of formula (II) comprises the following steps: (1) 1,3-diphenylacetone and anhydrous ethanol are added to a reaction vessel in a weight ratio of (1-3): (3-7), stirred evenly, and hydrogen sulfide and hydrogen chloride dry gases are introduced successively for 3-7 hours. The reaction temperature is controlled at 0-6°C. After 10-12 hours, the precipitate is vacuum dried to obtain a thiol intermediate; (2) Anhydrous ethanol and the thiol intermediate are added to the reaction vessel. After they are fully dissolved, ferric chloride and water are added. The weight ratio of the thiol intermediate, ethanol, ferric chloride and water is (1-3): (2-5): (2-4): (2-3). The mixture is stirred and reacted at 0-10° C. for 4-6 hours. A white powdery substance is precipitated. The crude product is obtained by filtration, recrystallization is performed with n-hexane, and vacuum drying is performed to obtain a thioether-type tetracyclic sulfur compound of formula (II).

5. The use according to any one of claims 1 to 4, characterized in that The mass ratio of the high-refractive-index thioether-type episulfide compound to the isothiocyanate compound, the isocyanate compound or a mixture thereof is (30-70): (10-50).

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