A raw material composition for preparing a polyurethane optical material having a medium-high refractive index

Abstract

A raw material composition for preparing a medium-high refractive index polyurethane optical material and optical coating material, comprising A component polyisocyanate, B component cyclo-trimeric sulfur-tris (2-mercaptoethyl sulfanyl) thiol represented by formula I, and C component naphthyl-bis (thioethyl acrylate) represented by formula II. The composition is used for preparing a polyurethane optical material or optical coating, and the product has high light transmittance, medium-high refractive index, excellent mechanical properties and protection against harmful light, etc. advantages, while effectively controlling the refractive index, reducing the production cost of high refractive index, high precision optical components, and expanding the application range of optical materials. (I) (II).

Description

Technical Field

[0001] This invention belongs to the field of optical materials technology, specifically relating to a raw material composition for preparing medium-high refractive index polyurethane optical materials and optical coating materials, as well as its preparation method and application. Background Technology

[0002] In the field of optical materials, ultra-high refractive index optical resins and medium-high refractive index optical resins each have their own unique characteristics. Ultra-high refractive index optical resins, with their excellent refractive properties, excel in lens lightweighting and precision, significantly reducing lens thickness and improving wearing comfort while maintaining optical performance, making them particularly suitable for manufacturing high-prescription lenses. However, from a practical application perspective, medium-high refractive index optical resins demonstrate stronger market competitiveness. For example, acrylic lenses polymerized from acrylates, and medium-high refractive index polyurethane lenses polymerized from polyisocyanates and thiol compounds, are used far more extensively than ultra-high refractive index products, and offer significant advantages in cost control, resulting in higher cost-effectiveness and meeting the needs of the mass consumer market, thus maintaining a dominant position. Furthermore, the production process for medium-high refractive index resins is more mature, and the supply chain is more stable. These factors collectively contribute to their status as the mainstream choice in the current optical lens market, holding an irreplaceable position in the field of low-to-medium prescription correction.

[0003] On the other hand, the adverse effects of eye exposure to ultraviolet light with wavelengths of 380–385 nm have always existed. In addition, in recent years, blue light with wavelengths of around 385–445 nm, contained in natural light and light emitted from the screens of office equipment LCD displays and portable devices such as smartphones, has caused eye fatigue, pain, and other problems, and its impact on the eyes has gradually become a concern. There is a desire to reduce the amount of blue light, from ultraviolet light to below 445 nm, exposed to the eyes.

[0004] In view of this, there is an urgent need to improve the raw materials and processes of medium and high refractive optical materials in order to achieve high-quality, high-efficiency, and economical technical results, so as to meet the needs of the optical materials industry upgrading. Summary of the Invention

[0005] The present invention aims to provide a raw material composition for a medium-high refractive index polyurethane optical material and an optical coating material. Both compositions contain a cyclotrisulfide-tris(2-mercaptoethylthio)thiol compound with an ultra-high refractive index as shown in Formula I and a naphthyl-bis(thioethyl acrylate) compound with a medium-high refractive index as shown in Formula II. By blending compounds with different refractive indices, the refractive index can be controlled while ensuring basic optical and mechanical properties. At the same time, by adding a light absorber, harmful ultraviolet rays and blue light can be effectively protected, which can be used for casting or surface coating of precision optical lenses.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A raw material composition for preparing medium-to-high refractive index polyurethane optical materials, the composition comprising the following components:

[0008] Component A: Polyisocyanate, 35-50 parts by weight;

[0009] Component B: Cyclotrisulfide-tris(2-mercaptoethylthio)thiol as shown in Formula I, 30-45 parts by weight;

[0010] Component C: Naphthyl-bis(thioethyl acrylate) as shown in Formula II, 5 to 15 parts by weight;

[0011]

[0012] (I)

[0013]

[0014] (II).

[0015] The raw material composition for preparing medium-high refractive index polyurethane optical materials as described above, preferably, further comprises:

[0016] Component D: Light absorber, 0.3~2 parts by weight.

[0017] The raw material composition for preparing medium-high refractive index polyurethane optical materials as described above, preferably, the light absorber is a combination of ultraviolet absorber and blue light absorber;

[0018] More preferably, the ultraviolet absorber is selected from: phenyl benzoate, o-nitroaniline, 2-(2'hydroxy-3',5'-di-tert-phenyl)-5-chlorobenzotriazole, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, resorcinol monobenzoate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, hexamethylphosphoric acid triamine, UV-234, UV-326, UV-327, UV-328, UV-329, UV-360, UV-531 and UV-928;

[0019] More preferably, the blue light absorber is selected from at least one of: octaethylporphyrin zinc, octaethylporphyrin nickel, 5,10,15,20-tetra(pentafluorophenyl)porphyrin zinc, tetraphenylporphyrin zinc, hydrogen-bonded quinoline ketone, and N-vinyl5-vinyluracil.

[0020] In the above-described raw material composition for preparing medium-high refractive index polyurethane optical materials, preferably, the weight ratio of the ultraviolet absorber to the blue light absorber is 1:(0.3~2.5).

[0021] The raw material composition for preparing medium-to-high refractive index polyurethane optical materials as described above preferably includes a polyisocyanate selected from at least one of diphenylmethane diisocyanate, hexamethylene diisocyanate, toluene-2,4-diisocyanate, m-phenylenedimethyl isocyanate, isophorone diisocyanate, diphenyl ether diisocyanate, dicyclohexylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, cyclohexane diisocyanate, dithiodiethyl diisocyanate, tetramethylene diisocyanate, thiodihexyl diisocyanate, thiodipropyl diisocyanate, dithiodipropyl diisocyanate, triphenylmethane triisocyanate, phenylenedimethyl diisocyanate, lysine triisocyanate, and o-toluidine diisocyanate.

[0022] On the other hand, the present invention provides a raw material composition for preparing medium-high refractive index polyurethane optical coating materials, the composition comprising the following components:

[0023] Component a: Polyisocyanate, 40-50 parts by weight;

[0024] Component b: Cyclotrisulfide-tris(2-mercaptoethylthio)thiol as shown in Formula I, 35~45 parts by weight;

[0025] Component c: Naphthyl-bis(thioethyl acrylate) as shown in Formula II, 5 to 9 parts by weight;

[0026] Component d: active diluent or wetting and dispersing agent, 0.8~1.5 parts by weight.

[0027] The raw material composition for preparing medium-high refractive index polyurethane optical coating materials as described above, preferably, the active diluent is at least one of benzyl acrylate, ethoxyphenol acrylate, biphenylmethanol acrylate, o-phenylphenoxyethyl acrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate or trimethylolpropane triacrylate.

[0028] The wetting and dispersing agent is BYK acrylate wetting and dispersing agent or F420 type wetting and dispersing agent.

[0029] The raw material composition for preparing medium-high refractive index polyurethane optical coating materials as described above, preferably, further comprises:

[0030] Component e: Light absorber, 0.3~2 parts by weight.

[0031] The raw material composition for preparing medium-high refractive index polyurethane optical coating materials as described above, preferably, the light absorber is a combination of ultraviolet absorber and blue light absorber;

[0032] The ultraviolet absorbers are selected from: phenyl benzoate, o-nitroaniline, 2-(2'hydroxy-3',5'-di-tert-phenyl)-5-chlorobenzotriazole, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, resorcinol monobenzoate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, hexamethylphosphoric acid triamine, UV-234, UV-326, UV-327, UV-328, UV-329, UV-360, UV-531 and UV-928;

[0033] The blue light absorber is selected from at least one of the following: octaethylporphyrin zinc, octaethylporphyrin nickel, 5,10,15,20-tetra(pentafluorophenyl)porphyrin zinc, tetraphenylporphyrin zinc, dihydroxyquinoline ketone, and N-vinyl-5-vinyluracil;

[0034] The weight ratio of the ultraviolet absorber to the blue light absorber is 1:(0.3~2.5).

[0035] The raw material composition for preparing medium-to-high refractive index polyurethane optical coating materials as described above preferably includes a polyisocyanate selected from at least one of diphenylmethane diisocyanate, hexamethylene diisocyanate, toluene-2,4-diisocyanate, m-phenylenedimethyl isocyanate, isophorone diisocyanate, diphenyl ether diisocyanate, dicyclohexylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, cyclohexane diisocyanate, dithiodiethyl diisocyanate, tetramethylene diisocyanate, thiodihexyl diisocyanate, thiodipropyl diisocyanate, dithiodipropyl diisocyanate, triphenylmethane triisocyanate, phenylenedimethyl diisocyanate, lysine triisocyanate, and o-toluidine diisocyanate.

[0036] The beneficial effects of this invention are as follows:

[0037] (1) The cyclic trisulfide-tris(2-mercaptoethylthio)thiol compound in the composition contains multiple thiol groups in its molecular structure, which gives it high reactivity and ultra-high refractive index.

[0038] (2) Naphthyl-bis(thioethyl acrylate) compounds have a stable naphthalene ring structure, good antistatic properties, and symmetrical connection of ethyl chains and acrylate groups at both ends, balancing strength and toughness and possessing a medium-high refractive index.

[0039] (3) By compounding thiol compounds with high and low refractive indices, the refractive index can be precisely controlled while maintaining basic optical and mechanical properties. The refractive index range is adjustable between 1.63 and 1.70.

[0040] (4) The composition integrates UV and blue light protection functions, effectively blocking harmful light, meeting the stringent requirements of high-end optical devices for material performance, and improving the overall performance of the optical system. Attached Figure Description

[0041] Figure 1 FT-IR infrared spectrum of the cyclic trisulfide-tris(2-mercaptoethylthio)thiol compound prepared in Example 1.

[0042] Figure 2 FT-IR infrared spectrum of the naphthyl-bis(thioethyl acrylate) compound prepared in Preparation Example 2. Detailed Implementation

[0043] The present invention will be further described below through specific embodiments, but this does not imply a limitation on the scope of protection of the present invention.

[0044] Preparation Example 1: Preparation of cyclic trisulfide-tris(2-mercaptoethylthio)thiol.

[0045] (1) 1050g of thiourea was added to a reaction vessel containing 1550g of ethanol and 600g of water, which was equipped with a stirrer, a temperature controller, a vent pipe and a reflux condenser. After mixing evenly, the mixture was heated to 55°C. 190g of paraformaldehyde was added dropwise over 40 minutes. Then, 25g of p-toluenesulfonic acid was added dropwise in two batches with an interval of 1.5 hours in between. Under continuous N2 protection, the temperature was raised to 90°C and the reaction was carried out for 6 hours. Byproducts were removed by hot filtration. The filtrate was naturally cooled to room temperature and then lowered to 5°C to crystallize. After filtration, washing and drying, 268.4g of 1,3,5-trithionhexane was obtained.

[0046] (2) Add 180g of 1,3,5-trithiacyclohexane to a reaction vessel containing 400g of THF and 1000g of dichloromethane solvent, equipped with a stirrer, a vent pipe, and a temperature control device. Add 8.0g of boron trifluoride diethyl ether complex catalyst at room temperature and stir for 25 minutes for pre-activation. Add 385g of ethylenedithiol dropwise over 40 minutes, continue under N2 protection, add 0.6g of antioxidant 2,6-di-tert-butyl-p-cresol, and heat to 45℃. The reaction mixture was stirred at rpm for 6.5 h, naturally cooled to room temperature, quenched with saturated NaHCO3 solution in an ice bath, and the aqueous phase was extracted three times with dichloromethane. The organic phases were combined, washed with saturated NaCl solution, dried over NaSO4, filtered, and the solvent was removed by vacuum distillation. The crude product was subjected to column chromatography using 300-mesh silica gel, first eluted with petroleum ether / ethyl acetate (4:1), then with ethyl acetate / methanol (20:1), yielding 405.9 g of a pale yellow, viscous cyclic trisulfide-tris(2-mercaptoethylthio)thiol compound. Yield: 74.1%. Refractive index (nd): 1.832.

[0047] Fourier transform infrared (FT-IR) spectroscopy was performed on the product prepared in Preparation Example 1. The results are as follows: Figure 1 As shown, the strong absorption peaks at 2934–2857 cm⁻¹ are the antisymmetric and symmetric stretching vibrations of methylene (-CH₂-), the absorption peaks at 2553–2567 cm⁻¹ are the characteristic peaks of the stretching vibrations of -SH, the absorption peaks at 1367–1415 cm⁻¹ are the CH bending vibrations, the weaker absorption peaks at 820–884 cm⁻¹ are the characteristic vibrations of the trisulfide ring, the absorption peaks at 716–747 cm⁻¹ are the stretching vibrations of CS, and the weaker absorption peaks at 512–545 cm⁻¹ are the SS stretching vibrations in the cyclic trisulfide.

[0048] 1H NMR spectra: δ=3.85~4.10 ppm (m, 3H, CH proton on the ring), δ=2.81~2.94 ppm (t, 6H, SCH2-CH2-SH, α-methylene near the cyclic sulfide), δ=2.64-2.77 ppm (t, 6H, SCH2-CH2-SH, β-methylene near the thiol group), δ=1.43~1.65 ppm (brs, 3H, -SH).

[0049] Preparation Example 2: Preparation of naphthyl-bis(thioethyl acrylate) compound.

[0050] (1) 60g of 1,5-naphthyl dithiol powder was added to a reaction vessel containing 300g of ethanol and stirred. The mixture was kept in an ice bath at 5°C. After complete dissolution, 160g of 20wt% NaOH solution was added dropwise over 30 minutes. The solution gradually turned dark red. 57g of carbon disulfide was added dropwise over 60 minutes. Stirring was continued for 3 hours. The solution gradually turned orange-yellow. The temperature was raised to room temperature and N2 protection was continued. Hydrochloric acid was added dropwise until pH=2.5. After stirring for 5.5 hours, a solid precipitated out. The solid product collected by filtration was dissolved in hot ethanol. Activated carbon was added for decolorization. The activated carbon was removed by hot filtration. The product was cooled to 5°C to crystallize. The product was filtered, washed, and dried under vacuum to obtain 60.1g of 1,5-naphthyl dithiol crystals.

[0051] (2) 155 g of 1,5-naphthalenedithiol and 170 g of pyridine catalyst were added to a reaction vessel containing 450 g of acetonitrile and 200 g of acetone with stirring. N2 was introduced, and the mixture was kept in an ice bath at 5 °C. After complete dissolution, 225 g of chloroethyl acrylate was added dropwise over 45 minutes. The mixture was then brought to room temperature and stirred for 6 hours. The mixture was filtered to remove salts, washed, and the solvent was collected by distillation. The crude product was then eluted with a gradient of oil ether / ethyl acetate to obtain 287.4 g of naphthyl-bis(thioethyl acrylate) compound. Yield: 85.4%. Refractive index (nd): 1.615.

[0052] Fourier transform infrared (FT-IR) spectroscopy was performed on the product prepared in Preparation Example 2. Figure 1 As shown in the curve analysis, the absorption peaks at 3080–3010 cm⁻¹ correspond to aromatic CH stretching vibrations (naphthalene ring); 3002–2853 cm⁻¹ correspond to aliphatic CH stretching vibrations (-CH₂-); 2985–2964 cm⁻¹ correspond to =CH₂ asymmetric stretching; 2920–2852 cm⁻¹ correspond to -CH₂- symmetric and asymmetric stretching vibrations; 1724–1735 cm⁻¹ correspond to C=O stretching vibrations; 1635–1620 cm⁻¹ correspond to C=C stretching vibrations in acrylates; 1610–1583 cm⁻¹ correspond to naphthalene ring skeletal vibrations; 1511–1447 cm⁻¹ correspond to naphthalene ring C=C stretching; 1318–1147 cm⁻¹ correspond to ester group COC asymmetric and symmetric stretching vibrations; and 985–810 cm⁻¹ corresponds to... The absorption peak at 758-696 cm⁻¹ is due to the out-of-plane bending vibration of =CH, the absorption peak at 758-696 cm⁻¹ is the characteristic absorption of naphthalene ring substitution, and the absorption peak at 709-622 cm⁻¹ is due to the stretching vibration of CS.

[0053] 1H NMR spectrum analysis: δ = 7.90~7.32 ppm (m, 6H, C10H6), 6.35~6.44 ppm (dd, 2H, -CH= in 2×-CH=CH2), 6.12~6.19 ppm (dd, 2H, trans=CH2 in -CH=CH2), 5.82~5.90 ppm (dd, 2H, cis=CH2 in -CH=CH2), 4.22~4.35 ppm (t, 4H, -OCO-CH2-CH2-), 2.96~3.10 ppm (t, 4H, -CH2-CH2-S-).

[0054] Example 1: Preparation of modified polyurethane optical materials.

[0055] 40g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol and 50g of diphenylmethane diisocyanate prepared in Preparation Example 1 were added to a reaction vessel. 8.5g of naphthyl-bis(thioethyl acrylate) and 2.5g of benzyl acrylate diluent prepared in Preparation Example 2 were added. The mixture was heated to 45°C and stirred for 35 min. Then, 0.1g of N-vinyl-5-vinyluracil, 0.2g of UV absorber UV-326, and 0.2g of octaethylporphyrin nickel were added while stirring. The mixture was cooled to 38°C, and then 0.06g of dibutyltin dilaurate and 0.05g of azobisisoheptanenitrile were added. Stirring was continued for 20 min, followed by vacuum degassing for 20 min. The degassed mixture was poured into a tempered mold and cured at 45°C for 2.5 h → 65°C for 2.5 h → Annealing at 80℃ for 2 hours, then annealing at 80℃→30℃, with slow cooling at 1.5℃ / min to obtain modified polyurethane optical materials.

[0056] Example 2: Preparation of modified polyurethane optical materials.

[0057] 35g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol and 50g of diphenylmethane diisocyanate prepared in Preparation Example 1 were added to a reaction vessel, followed by 10g of naphthyl-bis(thioethyl acrylate) prepared in Preparation Example 2. The mixture was heated to 45°C and stirred for 35 min. 0.15g of UV-326 and 0.35g of UV-329 ultraviolet absorbers were added while stirring. The mixture was cooled to 38°C and then 0.06g of dibutyltin dilaurate and 0.05g of azobisisoheptanenitrile were added. The mixture was stirred for another 20 min and then degassed under vacuum for 20 min. The degassed mixture was poured into a tempered mold and cured at 45°C for 2.5 h → 65°C for 2.5 h → 80°C for 2 h. Annealing was performed at 80°C → 30°C. Samples were taken by slowly cooling at 1.5°C / min to obtain the modified polyurethane optical material.

[0058] Example 3: Preparation of modified polyurethane optical materials.

[0059] 39g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol and 50g of hexamethylene diisocyanate prepared in Preparation Example 1 were added to a reaction vessel, followed by 8g of naphthyl-bis(thioethyl acrylate) prepared in Preparation Example 2. The mixture was heated to 45°C and stirred for 35 min. 0.25g of UV absorber UV-326 and 0.3g of octaethylporphyrin nickel were added while stirring. The mixture was cooled to 38°C and then 0.06g of dibutyltin dilaurate and 0.05g of azobisisobutyronitrile were added. The mixture was stirred for another 20 min and then degassed under vacuum for 20 min. The degassed mixture was poured into a tempered mold and cured at 45°C for 2.5 h → 65°C for 2.5 h → 80°C for 2 h. Annealing was performed at 80°C → 30°C. Samples were taken by slowly cooling at 1.5°C / min to obtain the modified polyurethane optical material.

[0060] Example 4: Preparation of modified polyurethane optical materials.

[0061] 40g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol, 25g of m-phenylenedimethyl isocyanate, and 25g of hexamethylene diisocyanate prepared in Preparation Example 1 were added to a reaction vessel, followed by 7.0g of naphthyl-bis(thioethyl acrylate) prepared in Preparation Example 2. The mixture was heated to 45°C and stirred for 35 min. 0.25g of UV absorber UV-326 and 0.3g of octaethylporphyrin nickel were added while stirring. The mixture was cooled to 38°C and then 0.06g of dibutyltin dilaurate and 0.05g of azobisisobutyronitrile were added. The mixture was stirred for another 20 min and then degassed under vacuum for 20 min. The degassed mixture was poured into a tempered mold and cured at 45°C for 2.5 h → 65°C for 2.5 h → 80°C for 2 h. Annealing was performed at 80°C → 30°C. Samples were taken by slowly cooling at 1.5°C / min to obtain the modified polyurethane optical material.

[0062] Example 5: Preparation of modified polyurethane optical materials.

[0063] 36g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol and 50g of toluene-2,4-diisocyanate prepared in Preparation Example 1 were added to a reaction vessel, followed by 9.0g of naphthyl-bis(thioethyl acrylate) prepared in Preparation Example 2. The mixture was heated to 45°C and stirred for 35 min. 0.25g of UV absorber UV-326 and 0.3g of octaethylporphyrin zinc were added while stirring. The mixture was cooled to 38°C and then 0.06g of dibutyltin dilaurate and 0.05g of azobisisoheptanenitrile were added. The mixture was stirred for another 20 min and then degassed under vacuum for 20 min. The degassed mixture was poured into a tempered mold and cured at 45°C for 2.5 h → 65°C for 2.5 h → 80°C for 2 h. Annealing was performed at 80°C → 30°C. Samples were taken by slowly cooling at 1.5°C / min to obtain the modified polyurethane optical material.

[0064] Example 6: Preparation of modified polyurethane optical materials.

[0065] 40g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol and 45g of isophorone diisocyanate prepared in Preparation Example 1 were added to a reaction vessel, followed by 6.0g of naphthyl-bis(thioethyl acrylate) prepared in Preparation Example 2. The mixture was heated to 45°C and stirred for 35 min. 0.5g of UV absorber UV-326 was added while stirring. The mixture was then cooled to 38°C and 0.06g of dibutyltin dilaurate and 0.05g of azobisisoheptanenitrile were added. The mixture was stirred for another 20 min and then degassed under vacuum for 20 min. The degassed mixture was poured into a tempered mold and cured at 45°C for 2.5 h → 65°C for 2.5 h → 80°C for 2 h. Annealing was performed at 80°C → 30°C. Samples were taken by slowly cooling at 1.5°C / min to obtain the modified polyurethane optical material.

[0066] Example 7: Preparation of modified polyurethane optical materials.

[0067] 35g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol, 20g of polymethylene polyphenyl polyisocyanate, and 30g of isophorone diisocyanate prepared in Preparation Example 1 were added to a reaction vessel, followed by 8.5g of naphthyl-bis(thioethyl acrylate) prepared in Preparation Example 2. The mixture was heated to 45°C and stirred for 35 min. 0.2g of UV-326 and 0.4g of UV-329 ultraviolet absorbers were added while stirring. The mixture was cooled to 38°C and then 0.05g of dibutyltin dilaurate and 0.04g of azobisisoheptanenitrile were added. The mixture was stirred for another 20 min and then degassed under vacuum for 20 min. The degassed mixture was poured into a tempered mold and cured at 45°C for 2.5 h → 65°C for 2.5 h → 80°C for 2 h. Annealing was performed at 80°C → 30°C. Samples were taken by slowly cooling at 1.5°C / min to obtain the modified polyurethane optical material.

[0068] Example 8: Preparation of modified polyurethane optical materials.

[0069] 35g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol and 50g of dicyclohexylmethane diisocyanate prepared in Preparation Example 1 were added to a reaction vessel, followed by 7.5g of naphthyl-bis(thioethyl acrylate) prepared in Preparation Example 2. The mixture was heated to 45°C and stirred for 35 min. 0.2g of UV-326 and 0.3g of dihydroxyquinoline were added while stirring. The mixture was cooled to 38°C and then 0.05g of dibutyltin dilaurate and 0.04g of azobisisobutyronitrile were added. The mixture was stirred for another 20 min and then degassed under vacuum for 20 min. The degassed mixture was poured into a tempered mold and cured at 45°C for 2.5 h → 65°C for 2.5 h → 80°C for 2 h. Annealing was performed at 80°C → 30°C. Samples were taken by slowly cooling at 1.5°C / min to obtain the modified polyurethane optical material.

[0070] Example 9: Preparation of modified polyurethane optical coating.

[0071] 38g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol and 45g of diphenylmethane diisocyanate prepared in Preparation Example 1 were added to a reaction vessel, followed by 5.5g of naphthyl-bis(thioethyl acrylate) and 1.2g of F420 wetting and dispersing agent prepared in Preparation Example 2. The mixture was heated to 50°C and stirred for 25 minutes. 0.3g of UV-326 and 0.3g of dihydroxyquinoline were added, and the mixture was cooled to 35°C. 0.1g of 1-hydroxycyclohexylphenyl ketone and 0.2g of 2-hydroxy-2-methyl-1-phenylpropanone 1173 were added as photoinitiators. After stirring for 20 minutes, the mixture was allowed to stand for 25 minutes to mature, resulting in a coating prepolymer solution. The prepolymer solution was filtered through a filter membrane to degas and then spin-coated onto the substrate surface at 2500 rpm. The coated sheet was then placed under a light intensity of 50~120mW / cm². 2The modified polyurethane optical coating was obtained by gradient irradiation for 45 seconds under a UV-LED curing machine.

[0072] Example 10: Preparation of modified polyurethane optical coating.

[0073] 35g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol and 50g of polymethylene polyphenyl polyisocyanate prepared in Preparation Example 1 were added to a reaction vessel, followed by 7.5g of naphthyl-bis(thioethyl acrylate) and 1.3g of F420 wetting and dispersing agent prepared in Preparation Example 2. The mixture was heated to 50°C and stirred for 25 minutes. 0.2g of UV-326 and 0.35g of UV-327 were added, and the mixture was cooled to 35°C. 0.1g of 1-hydroxycyclohexylphenyl ketone and 0.2g of 2-hydroxy-2-methyl-1-phenylpropanone 1173 photoinitiator were added. After stirring for 20 minutes, the mixture was allowed to stand for 25 minutes to mature, resulting in a prepolymer solution for the coating. The prepolymer solution was filtered through a filter membrane to degas and then spin-coated onto the substrate surface at a speed of 2500 rpm. The coated sheet was then placed under a light intensity of 50~120mW / cm². 2 The modified polyurethane optical coating was cured by gradient irradiation for 45 seconds under a UV-LED curing machine.

[0074] Example 11: Preparation of modified polyurethane optical coating.

[0075] 35g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol and 50g of toluene-2,4-diisocyanate prepared in Preparation Example 1 were added to a reaction vessel, followed by 9.5g of naphthyl-bis(thioethyl acrylate) and 1.3g of F420 wetting and dispersing agent prepared in Preparation Example 2. The mixture was heated to 50°C and stirred for 25 minutes. 0.2g of UV-326 and 0.35g of octaethylporphyrin nickel were added. The mixture was then cooled to 35°C, and 0.1g of 1-hydroxycyclohexylphenyl ketone and 0.2g of 2-hydroxy-2-methyl-1-phenylpropanone 1173 photoinitiator were added. After stirring for 20 minutes, the mixture was allowed to stand for 25 minutes to mature, resulting in a prepolymer solution for the coating. The prepolymer solution was filtered through a filter membrane to degas and then spin-coated onto the substrate surface at a speed of 2500 rpm. The coated sheet was then placed under a light intensity of 50~120mW / cm². 2 The modified polyurethane optical coating was cured by gradient irradiation for 45 seconds under a UV-LED curing machine.

[0076] Example 12: Preparation of modified polyurethane optical coating.

[0077] 35g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol and 45g of isophorone diisocyanate prepared in Preparation Example 1 were added to a reaction vessel, followed by 6.5g of naphthyl-bis(thioethyl acrylate) and 1.3g of F420 wetting and dispersing agent prepared in Preparation Example 2. The mixture was heated to 50°C and stirred for 25 minutes. 0.2g of UV-326, 0.2g of UV-328, and 0.3g of octaethylporphyrin zinc were added. The mixture was then cooled to 35°C, and 0.1g of 1-hydroxycyclohexylphenyl ketone and 0.2g of 2-hydroxy-2-methyl-1-phenylpropanone 1173 were added. After stirring for 20 minutes, the mixture was allowed to stand for 25 minutes to mature, resulting in a coating prepolymer solution. The prepolymer solution was filtered through a filter membrane to degas and then spin-coated onto the substrate surface at 2500 rpm. The coated sheet was then placed under light with an intensity of 50~120mW / cm². 2 The modified polyurethane optical coating was cured by gradient irradiation for 45 seconds under a UV-LED curing machine.

[0078] Example 13: Preparation of modified polyurethane optical coating.

[0079] 35g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol and 45g of dicyclohexylmethane diisocyanate prepared in Preparation Example 1 were added to a reaction vessel, followed by 6.5g of naphthyl-bis(thioethyl acrylate) and 1.3g of F420 wetting and dispersing agent prepared in Preparation Example 2. The mixture was heated to 50°C and stirred for 25 minutes. 0.2g of UV-326 and 0.3g of UV-328 were added, and the mixture was cooled to 35°C. 0.1g of 1-hydroxycyclohexylphenyl ketone and 0.2g of 2-hydroxy-2-methyl-1-phenylpropanone 1173 were added. After stirring for 20 minutes, the mixture was allowed to stand for 25 minutes to mature, resulting in a coating prepolymer solution. The prepolymer solution was filtered through a filter membrane to degas and then spin-coated onto the substrate surface at 2500 rpm. The coated sheet was then placed under light with an intensity of 50~120mW / cm². 2 The modified polyurethane optical coating was cured by gradient irradiation for 45 seconds under a UV-LED curing machine.

[0080] Example 14: Preparation of modified polyurethane optical coating.

[0081] 40g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol and 48g of hexamethylene diisocyanate prepared in Preparation Example 1 were added to a reaction vessel, followed by 6.0g of naphthyl-bis(thioethyl acrylate) and 1.3g of F420 wetting and dispersing agent prepared in Preparation Example 2. The mixture was heated to 50°C and stirred for 25 minutes. 0.2g of UV-326, 0.2g of UV-327, and 0.2g of UV-328 were added. The mixture was then cooled to 35°C, and 0.1g of 1-hydroxycyclohexylphenyl ketone and 0.2g of 2-hydroxy-2-methyl-1-phenylpropanone 1173 were added. After stirring for 20 minutes, the mixture was allowed to stand for 25 minutes to mature, resulting in a coating prepolymer solution. The prepolymer solution was filtered through a filter membrane to degas and then spin-coated onto the substrate surface at a speed of 2500 rpm. The coated sheet was then placed under a light intensity of 50~120mW / cm². 2 The modified polyurethane optical coating was cured by gradient irradiation for 45 seconds under a UV-LED curing machine.

[0082] Example 15: Preparation of modified polyurethane optical coating.

[0083] 40g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol, 15g of m-phenylenedimethyl isocyanate, and 35g of isophorone diisocyanate prepared in Preparation Example 1 were added to a reaction vessel. Then, 7.5g of naphthyl-bis(thioethyl acrylate) and 1.3g of F420 wetting and dispersing agent prepared in Preparation Example 2 were added. The mixture was heated to 50°C and stirred for 25 minutes. 0.2g of UV-326 and 0.4g of octaethylporphyrin nickel were added. The mixture was cooled to 35°C, and 0.1g of 1-hydroxycyclohexylphenyl ketone and 0.2g of 2-hydroxy-2-methyl-1-phenylpropanone 1173 were added. After stirring for 20 minutes, the mixture was allowed to stand for 25 minutes to mature, resulting in a coating prepolymer solution. The prepolymer solution was filtered through a filter membrane to degas and then spin-coated onto the substrate surface at 2500 rpm. The coated sheet was then placed under light with an intensity of 50~120 mW / cm². 2 The modified polyurethane optical coating was cured by gradient irradiation for 45 seconds under a UV-LED curing machine.

[0084] Comparative Example 1: Preparation of polyurethane optical materials.

[0085] The same preparation conditions as in Example 1 were used, except that cyclotrisulfide-tris(2-mercaptoethylthio)thiol was replaced with polythiol 504 and naphthyl-bis(thioethyl acrylate) was replaced with bisphenol A methacrylate.

[0086] 40g of polythiol 504 and 50g of diphenylmethane diisocyanate were added to a reaction vessel, along with 8.5g of bisphenol A methacrylate and 2.5g of benzyl acrylate. The mixture was heated to 45℃ and stirred for 35 minutes. Then, 0.1g of N-vinyl-5-vinyluracil, 0.2g of UV absorber UV-326, and 0.2g of octaethylporphyrin nickel were added. The mixture was cooled to 38℃ and then 0.06g of dibutyltin dilaurate and 0.05g of azobisisoheptanenitrile were added. The mixture was stirred for another 20 minutes and then degassed under vacuum for 20 minutes. The degassed mixture was poured into a tempered mold and cured at 45℃ for 2.5 hours, then at 65℃ for 2.5 hours, and finally at 80℃ for 2 hours. The mixture was then annealed at 80℃ for 30℃ and slowly cooled at 1.5℃ / min to obtain a polyurethane optical material.

[0087] Comparative Example 2: Preparation of polyurethane optical materials.

[0088] The same preparation conditions as in Example 1 were used, except that cyclotrisulfide-tris(2-mercaptoethylthio)thiol was replaced with polythiol 504, and the following preparation was carried out.

[0089] 40g of polythiol 504 and 50g of diphenylmethane diisocyanate were added to a reaction vessel, along with 8.5g of naphthyl-bis(thioethyl acrylate) and 2.5g of benzyl acrylate diluent. The mixture was heated to 45℃ and stirred for 35 minutes. Then, 0.1g of N-vinyl-5-vinyluracil, 0.2g of UV absorber UV-326, and 0.2g of octaethylporphyrin nickel were added. The mixture was cooled to 38℃ and then 0.06g of dibutyltin dilaurate and 0.05g of azobisisoheptanenitrile were added. The mixture was stirred for another 20 minutes and then degassed under vacuum for 20 minutes. The degassed mixture was poured into a tempered mold and cured at 45℃ for 2.5 hours, then at 65℃ for 2.5 hours, and finally at 80℃ for 2 hours. The mixture was then annealed at 80℃ for 30℃ and slowly cooled at 1.5℃ / min to obtain a polyurethane optical material.

[0090] Comparative Example 3: Preparation of polyurethane optical materials.

[0091] The same preparation conditions as in Example 1 were used, except that naphthyl-bis(thioethyl acrylate) was replaced with bisphenol A methacrylate, and the following preparation was carried out.

[0092] 40g of cyclotrisulfide-tris(2-mercaptoethylthio)thiol and 50g of diphenylmethane diisocyanate were added to a reaction vessel, along with 8.5g of bisphenol A methacrylate and 2.5g of benzyl acrylate. The mixture was heated to 45℃ and stirred for 35min. Then, 0.1g of N-vinyl-5-vinyluracil, 0.2g of UV absorber UV-326, and 0.2g of octaethylporphyrin nickel were added. The mixture was cooled to 38℃ and then 0.06g of dibutyltin dilaurate and 0.05g of azobisisoheptanenitrile were added. The mixture was stirred for another 20min and then degassed under vacuum for 20min. The degassed mixture was poured into a tempered mold and cured at 45℃ for 2.5h → 65℃ for 2.5h → 80℃ for 2h. The mixture was then annealed at 80℃ → 30℃. Samples were taken by slowly cooling at 1.5℃ / min to obtain polyurethane optical material.

[0093] Comparative Example 4: A polyurethane optical coating was prepared.

[0094] The same preparation conditions as in Example 15 were used, except that cyclotrisulfide-tris(2-mercaptoethylthio)thiol was replaced with polythiol 504 and naphthyl-bis(thioethyl acrylate) was replaced with pentaerythritol tetraacrylate.

[0095] Add 40g of polythiol 504, 15g of isophthalic dimethyl isocyanate, and 35g of isophorone diisocyanate to a reaction vessel, then add 7.5g of pentaerythritol tetraacrylate. Heat to 50℃ and stir for 25 minutes. Add 0.2g of UV-326 and 0.4g of octaethylporphyrin nickel. Cool to 35℃, then add 0.1g of 1-hydroxycyclohexylphenyl ketone and 0.2g of 2-hydroxy-2-methyl-1-phenylpropanone 1173. Stir for 20 minutes, then let stand for 25 minutes to mature, obtaining the coating prepolymer solution. Filter the prepolymer solution through a filter membrane to degas, and spin-coat it onto the substrate surface at 2500 rpm. Then place the coated sheet under light intensity of 50~120mW / cm². 2 The modified polyurethane optical coating was cured by gradient irradiation for 45 seconds under a UV-LED curing machine.

[0096] Example 16 Optical performance testing experiment.

[0097] The modified polyurethane optical materials and optical coatings prepared in Examples 1-15 and Comparative Examples 1-4 were tested for transmittance, refractive index, UV protection, and blue light protection. Transmittance was measured using a Lambda 650 S UV-Vis spectrophotometer (PerkinElmer Chemical Analysis Instruments, Inc.), and refractive index was measured using an Rx-7000 digital refractometer (Shanghai Optical Instrument Equipment Co., Ltd.). The test results are detailed in Tables 1 and 2.

[0098] Table 1. Optical properties of the prepared samples.

[0099] sample Visible light Refractive index Below 380nm 440nm Example 1 90.7 1.693 ＜0.01 ＜15.3 Example 2 90.9 1.684 ＜0.01 ＜67.7 Example 3 90.7 1.662 ＜0.01 ＜15.5 Example 4 90.6 1.668 ＜0.01 ＜15.5 Example 5 90.6 1.676 ＜0.01 ＜15.5 Example 6 90.8 1.651 ＜0.01 ＜67.2 Example 7 90.7 1.665 ＜0.01 ＜67.9 Example 8 90.6 1.667 ＜0.01 ＜15.4 Comparative Example 1 90.7 1.613 ＜0.01 ＜15.3 Comparative Example 2 90.7 1.629 ＜0.01 ＜15.3 Comparative Example 3 90.7 1.643 ＜0.01 ＜15.3

[0100] Test results show that the modified polyurethane optical material prepared by this invention has a medium-high refractive index that is adjustable. In Examples 2, 6, and 7, no blue light absorber was added, and the transmittance (%) at 440nm reached <67.2~67.9, which is due to the partial absorption of blue light by the interaction of the ultraviolet absorber with the naphthyl group.

[0101]

[0102] Test results show that the modified polyurethane optical coating prepared by this invention has a medium-high refractive index that is adjustable.

[0103] Example 17 Impact strength test experiment.

[0104] Impact strength tests were conducted on the polyurethane optical materials prepared in Example 1 and Comparative Example 1. The material's impact strength was determined by the highest steel ball mass that produced no cracks after three impacts (e.g., a 90g steel ball impact without cracking, while a 100g steel ball impact caused cracks). The test method involved fixing a substrate with a certain curvature at its center, convex side up, to the bottom of the instrument. Steel balls of different masses (95g, 100g, 105g, and 110g) were dropped vertically from a height of 1.30m onto the center of the substrate surface, with each mass tested three times. The steel ball impact test results showed that the modified polyurethane optical substrate prepared in Example 1 had an impact strength of 105g, while the unmodified polyurethane optical substrate in Comparative Example 1 had an impact strength of 100g, indicating that the sample in Example 1 had better impact resistance.

[0105] Example 18 Adhesion test experiment.

[0106] A cross-cut test using adhesive tape was conducted. The method involved scratching the surface of the optical coatings prepared in Example 15 and Comparative Example 2 with a blade, then scratching from a perpendicular angle, leaving 16 small squares on the coating surface. 3M invisible adhesive tape was then applied to the squares, and the tape was peeled off at a slightly faster and smoother speed. The coating peeling at the cross-cut points of the grid was observed using a magnifying glass. The scratch test results showed that the coating did not peel or flake, indicating good adhesion.

Claims

1. A raw material composition for preparing medium-to-high refractive index polyurethane optical materials, characterized in that, The composition comprises the following components: Component A: Polyisocyanate, 35-50 parts by weight; Component B: Cyclotrisulfide-tris(2-mercaptoethylthio)thiol as shown in Formula I, 30-45 parts by weight; Component C: Naphthyl-bis(thioethyl acrylate) as shown in Formula II, 5 to 15 parts by weight; （I） (II).

2. The raw material composition according to claim 1, characterized in that, The components also include: Component D: Light absorber, 0.3~2 parts by weight.

3. The raw material composition according to claim 2, characterized in that, The light absorber is a combination of ultraviolet absorber and blue light absorber; The ultraviolet absorbers are selected from: phenyl benzoate, o-nitroaniline, 2-(2'hydroxy-3',5'-di-tert-phenyl)-5-chlorobenzotriazole, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, resorcinol monobenzoate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, hexamethylphosphoric acid triamine, UV-234, UV-326, UV-327, UV-328, UV-329, UV-360, UV-531 and UV-928; The blue light absorber is selected from at least one of the following: octaethylporphyrin zinc, octaethylporphyrin nickel, 5,10,15,20-tetra(pentafluorophenyl)porphyrin zinc, tetraphenylporphyrin zinc, hydrogen-bonded quinoline ketone, and N-vinyl-5-vinyluracil.

4. The raw material composition according to claim 3, characterized in that, The weight ratio of the ultraviolet absorber to the blue light absorber is 1:(0.3~2.5).

5. The raw material composition according to any one of claims 1-4, characterized in that, The polyisocyanate is selected from at least one of diphenylmethane diisocyanate, hexamethylene diisocyanate, toluene-2,4-diisocyanate, m-phenylenedimethyl isocyanate, isophorone diisocyanate, diphenyl ether diisocyanate, dicyclohexylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, cyclohexane diisocyanate, dithiodiethyl diisocyanate, tetramethylene diisocyanate, thiodihexyl diisocyanate, thiodipropyl diisocyanate, dithiodipropyl diisocyanate, triphenylmethane triisocyanate, phenylenedimethyl diisocyanate, lysine triisocyanate, and o-toluidine diisocyanate.

6. A raw material composition for preparing medium-to-high refractive index polyurethane optical coating materials, characterized in that, The composition comprises the following components: Component a: Polyisocyanate, 40-50 parts by weight; Component b: Cyclotrisulfide-tris(2-mercaptoethylthio)thiol as shown in Formula I, 35~45 parts by weight; Component c: Naphthyl-bis(thioethyl acrylate) as shown in Formula II, 5 to 9 parts by weight; Component d: Reactive diluent or wetting and dispersing agent, 0.8~1.5 parts by weight （I） (II).

7. The raw material composition according to claim 6, characterized in that, The reactive diluent is at least one of benzyl acrylate, ethoxyphenol acrylate, biphenylmethanol acrylate, o-phenylphenoxyethyl acrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, or trimethylolpropane triacrylate. The wetting and dispersing agent is BYK acrylate wetting and dispersing agent or F420 type wetting and dispersing agent.

8. The raw material composition according to claim 6, characterized in that, The components also include: Component e: Light absorber, 0.3~2 parts by weight.

9. The raw material composition according to claim 8, characterized in that, The light absorber is a combination of ultraviolet absorber and blue light absorber; The ultraviolet absorbers are selected from: phenyl benzoate, o-nitroaniline, 2-(2'hydroxy-3',5'-di-tert-phenyl)-5-chlorobenzotriazole, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, resorcinol monobenzoate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, hexamethylphosphoric acid triamine, UV-234, UV-326, UV-327, UV-328, UV-329, UV-360, UV-531 and UV-928; The blue light absorber is selected from at least one of the following: octaethylporphyrin zinc, octaethylporphyrin nickel, 5,10,15,20-tetra(pentafluorophenyl)porphyrin zinc, tetraphenylporphyrin zinc, dihydroxyquinoline ketone, and N-vinyl-5-vinyluracil; The weight ratio of the ultraviolet absorber to the blue light absorber is 1:(0.3~2.5).

10. The raw material composition according to any one of claims 6-9, characterized in that, The polyisocyanate is selected from at least one of diphenylmethane diisocyanate, hexamethylene diisocyanate, toluene-2,4-diisocyanate, m-phenylenedimethyl isocyanate, isophorone diisocyanate, diphenyl ether diisocyanate, dicyclohexylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, cyclohexane diisocyanate, dithiodiethyl diisocyanate, tetramethylene diisocyanate, thiodihexyl diisocyanate, thiodipropyl diisocyanate, dithiodipropyl diisocyanate, triphenylmethane triisocyanate, phenylenedimethyl diisocyanate, lysine triisocyanate, and o-toluidine diisocyanate.

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