Polyurethane optical material with high refractive index and preparation method therefor

Abstract

A polyurethane optical material with a high refractive index and a preparation method therefor. The polyurethane optical material is formed by polymerization of a thioether-type episulfide compound having a high refractive index and an isothiocyanate compound and / or an isocyanate compound, wherein the structure of the thioether-type episulfide compound is represented by formula (I), formula (II) or formula (III), the refractive index thereof reaching 1.66-1.76, and the mass ratio of the thioether-type episulfide compound to the isothiocyanate compound, or the isocyanate compound or a mixture thereof is (30-70):(10-50). The polyurethane optical material has the advantages of high refractive index and light transmittance, low chromaticity, and excellent overall performance and can be used in various different optical substrates, thereby providing a broader range of material options for use in high-end optical components. The preparation method of the present invention is simple and practical, and the reaction process is highly controllable. In formula (I), R and R1 are the same or different, and are each H, CH3 or C6H5. In formula (II) and formula (III), R is H or CH3.

Description

High refractive index polyurethane optical material and preparation method thereof TECHNICAL FIELD

[0001] The present application belongs to the technical field of polyurethane optical material synthesis and preparation, and particularly relates to a high refractive index polyurethane optical material containing a sulfide type cyclic sulfur compound and a preparation method thereof. BACKGROUND

[0002] Optical system lightening refers to reducing the curvature, thickness and weight of optical equipment as much as possible under the premise of guaranteeing optical performance and function, miniaturizing, precision and integrating optical devices, and improving the refractive index is an important means to realize lightening. Western developed countries are at the world leading level due to earlier research. For example, Japan Mitsui Chemical uses mercapto (-SH) to replace the ternary mercaptan and isocyanate reaction to prepare a high refractive index polyurethane resin (product code MR), and the refractive index is from 1.67-1.76. Its product has long occupied the global market. US patent (US2011046285) discloses that a high refractive, high cyclic sulfur compound monomer is prepared by the reaction of an epoxy compound and a thiocyanate.

[0003] The refractive index is inversely proportional to the molecular volume and proportional to the molar refractive index, and the molar refractive index is proportional to the medium polarizability. In order to improve the refractive index of the resin, mainly through introducing the group with high molar refractive and small molecular volume in the molecular structure of the polymer. The high refractive polyurethane is widely used in high-end optical fields such as optical lens, instrument prism, light protection, LED lighting, intelligent automobile and window material, because it overcomes the opacity of traditional polyurethane, has high light transmittance, high strength and good impact resistance. In recent years, there are many related reports on introducing sulfur atoms to improve the refractive index of mercaptan monomer through molecular design. Because there is a d orbital outside the sulfur atom, the two pairs of electrons in the outermost layer are easily polarized, so that the sulfur atom has low molecular dispersion and high molecular refractive index.

[0004] The following are examples of several high sulfur compound monomer synthesis methods.

[0005] (1) The halogenated alkane is reacted with sodium hydrosulfide in an alcohol solution to obtain mercaptan, as shown in formula (1). The reaction temperature of this method is high, sodium hydrosulfide is not stable and is easy to decompose into Na2S at high temperature, and by-products are also easy to be generated, so the production process is difficult to control.

[0006] (2) The halogenated alkane is reacted with a thio acid under certain conditions to generate a mercaptan ester, and the mercaptan ester is hydrolyzed into mercaptan under OH - or H + conditions, as shown in formula (2). However, this method has low yield and high cost, which is not conducive to industrial scale production.

[0007] (3) Mercaptoethanol reacts with trichloropropane, refluxes with KOH solution containing ME, after liquid separation, under reduced pressure reflux to obtain 1,2,3-mercaptoethylthiopropyl. But mercaptoethanol is easy to be oxidized under high temperature and alkaline conditions to generate complex by-products, thus causing the sulfur alcohol to be yellow, which affects the product use.

[0008] (4) Diethyl tetra-sulfur is generated by condensation of sulfur monochloride and mercaptoethanol with petroleum ether as solvent, and isothiurea salt is obtained, and tetra-sulfur polythiol is obtained after hydrolysis. The method is complex and has high production cost, and in addition, the use of a large amount of toxic solvents is not conducive to environmental protection.

[0009] The sulfur alcohol compounds synthesized by the above chemical reactions have some problems. Some use sulfur-containing compounds to achieve higher refractive index optical materials, and some have a maximum refractive index of even more than 1.85, which has made important breakthroughs, but there is still a problem of low purity of the prepared sulfur-containing monomer. In the synthesis process, other side reactions often occur, resulting in low product purity, which cannot be used as optical materials. Only by traditional extraction, distillation and other methods, it is difficult to separate from the complex mixture, or the stability of the synthesized monomer is not enough, and the storage causes agglomeration or self-aggregation, which affects the use in the field of high-end optical components. Some have the problem of harsh synthesis process conditions, and it is difficult to scale up production. Therefore, advanced synthesis methods and technologies will increasingly show their importance in the development and application of new sulfur-containing compounds.

[0010] SUMMARY

[0011] In view of the above problems of the prior art, the present application provides a high refractive index polyurethane optical material and a preparation method thereof. A sulfur ether type sulfur compound monomer is used, and the refractive index reaches 1.66-1.76. The in-situ polymerization of the sulfur compound or its mixture with isothiocyanate or isocyanate is used to prepare a high refractive index polyurethane optical material. The polyurethane optical material has the advantages of high refractive index and light transmittance, low color, and strong comprehensive performance, and can be used for various different optical substrates, thereby providing a wider material selection range for the application of high-end optical components.

[0012] To achieve the above object, the present application provides the following technical scheme:

[0013] A high refractive index polyurethane optical material is prepared by polymerization of a high refractive index sulfur ether type sulfur compound and isothiocyanate compound and / or isocyanate compound; wherein the mass ratio of the high refractive index sulfur ether type sulfur compound to the isothiocyanate compound and / or the isocyanate compound or the mixture thereof is (30-70):(10-50).

[0014] The sulfide-type cyclic sulfur compound is selected from at least one of compounds represented by the following formula I, formula II and formula III:

[0015] wherein R and R1 are the same or different, each being H or CH3 or C6H5;

[0016] wherein R is H or CH3.

[0017] The high refractive index polyurethane optical material as described above, preferably, the isothiocyanate compound is an aliphatic polyisothiocyanate compound or a cycloaliphatic polyisothiocyanate compound having two or more isothiocyanate groups in the molecular structure.

[0018] The high refractive index polyurethane optical material as described above, preferably, the isothiocyanate compound is a compound having two or more isocyanate groups in the molecular structure.

[0019] The high refractive index polyurethane optical material as described above, preferably, the isothiocyanate compound is selected from at least one of lysine methyl ester diisothiocyanate, lysine triisothiocyanate, hexamethylene diisothiocyanate, m-xylylene diisothiocyanate, bis-isothiocyanato-methyl sulfide, bis-isothiocyanato-ethyl sulfide, bis-isothiocyanato-ethyl disulfide, bis-isothiocyanato-cyclohexane, isophorone diisothiocyanate, dicyclohexylmethane diisothiocyanate, cyclohexane diisothiocyanate, methylcyclohexane diisothiocyanate, bis-isothiocyanato-heptane and bis-isothiocyanato-tricyclodecane.

[0020] The high refractive index polyurethane optical material as described above, preferably, the isocyanate compound is selected from at least one of isophorone diisocyanate trimer (IPDIT), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), hexamethylene diisocyanate trimer (HDIT), xylene diisocyanate (XDI), isophorone diisocyanate (IPDI), phenylene diisocyanate, cyclohexane diisocyanate, methylene dianiline (MDI).

[0021] In another aspect, the present application provides a method for preparing the high refractive index polyurethane optical material as described above, the method comprising the following steps:

[0022] (1) mixing one of the sulfide-type cyclic sulfur compounds or a mixture thereof with an isothiocyanate compound or an isocyanate compound or a mixture thereof at a weight ratio of (30-70):(10-50) uniformly;

[0023] (2) adding a polymerization catalyst to the reactant obtained in step (1) above, pre-polymerizing at 50-80°C for 10-60 minutes, removing the gas bubbles under vacuum, and injecting into a lens mold;

[0024] (3) placing the mold containing the pre-polymer in a curing oven at 35-55°C for 2-10 hours, then gradually increasing the temperature to 80-100°C, continuing to place for 2-3 hours, and finally cooling to room temperature to remove the mold, thereby obtaining a high-refractive polyurethane optical material.

[0025] In the preparation method as described above, preferably, step (1) further comprises adding a thiol compound having a refractive index of 1.60-1.85 to the obtained mixture, and the amount of the thiol added is 30-65%.

[0026] In the preparation method as described above, preferably, the thiol is at least one selected from the group consisting of methanedithiol, ethanedithiol, methyl mercaptan, dimercaptomethane, dimercaptoethane, dimercaptopropane, trimercaptopropane, pentaerythritol, bismercapto-methyl benzene, and bismercapto-ethyl sulfide.

[0027] In the preparation method as described above, preferably, step (1) comprises mixing the isothiocyanate compound with the isocyanate compound, and the mixture is prepared by the following steps:

[0028] a. first melting the isothiocyanate compound by heating to 55-135°C, then adding the isocyanate compound to obtain the mixture;

[0029] b. adding triethyldiamine to the mixture, wherein the weight ratio of triethyldiamine to isothiocyanate compound is (0.1-0.3):(1-7).

[0030] In the preparation method as described above, preferably, step (1) further comprises adding a solvent, which is one selected from the group consisting of methanol, ethanol, propanol, dichloroethane, methyl ketone, ethyl ketone, acetone, and toluene, xylene, chloroform, chlorobenzene, diethyl ether, dioxane, and tetrahydrofuran, and the amount of the solvent added is 0.5-3 wt% of the reactant.

[0031] In the preparation method as described above, preferably, the polymerization catalyst is one or a mixture of triethylenediamine, dimethylthiuram disulfide, dibutyltin dilaurate, and isooctoate stannous, and the amount of the catalyst used is 1-3 wt% of the pre-polymer.

[0032] In another aspect, the present application provides a high-refractive thioether-type cyclic sulfur compound, which has the structure shown in formula I:

[0033] wherein R and R1 are the same or different, and each is H, CH3, or C6H5.

[0034] In another aspect, the present application provides a method for preparing the high refractive index sulfide-type cyclic sulfur compound I as described above, which comprises the following steps:

[0035] (1) 1,3-diphenylacetone and anhydrous ethanol are added into a reaction vessel in a weight ratio of (1-3):(3-7), stirred uniformly, and then dry hydrogen sulfide and hydrogen chloride gases are introduced for 3-7 hours, with the reaction temperature controlled at 0-6°C. After 10-12 hours, the precipitate is vacuum dried to obtain a thiol intermediate;

[0036] (2) The thiol intermediate, benzaldehyde and diethyl ether are mixed in a weight ratio of (1-2):(1-2):(100-150), and a catalyst in an amount of 1 / 8-1 / 12 of the weight of the thiol intermediate is added thereto. After being stirred at room temperature for 7-10 hours, the reaction is stopped, and then a saturated sodium chloride solution is added. After being stirred and mixed and then separated into layers, the upper diethyl ether layer is taken out, dried, decolorized with a clay adsorbent to be colorless and transparent, and then distilled to remove the diethyl ether solvent, thereby obtaining a viscous sulfide-type tricyclic sulfur compound I. The catalyst is one of hydrochloric acid, sulfuric acid, toluenesulfonic acid and p-toluenesulfonic acid.

[0037] In another aspect, the present application provides a high refractive index sulfide-type cyclic sulfur compound, which has a structure as shown in formula II:

[0038] In another aspect, the present application provides a method for preparing the high refractive index sulfide-type cyclic sulfur compound II as described above, which comprises the following steps:

[0039] (1) 1,3-diphenylacetone and anhydrous ethanol are added into a reaction vessel in a weight ratio of (1-3):(3-7), stirred uniformly, and then dry hydrogen sulfide and hydrogen chloride gases are introduced for 3-7 hours, with the reaction temperature controlled at 0-6°C. After 10-12 hours, the precipitate is vacuum dried to obtain a thiol intermediate;

[0040] (2) Anhydrous ethanol and the thiol intermediate are added into the reaction vessel, and after being 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). After being stirred at 0-10°C for 4-6 hours, a white powder is precipitated, which is filtered to obtain a crude product. The crude product is recrystallized with n-hexane, and then vacuum dried to obtain a sulfide-type tetracyclic sulfur compound II.

[0041] In another aspect, the present application provides a high refractive index sulfide-type cyclic sulfur compound, which has a structure as shown in formula III:

[0042] wherein R is H or CH3.

[0043] In another aspect, the present application provides a method for preparing the high-refractive-index sulfide-type cyclic sulfur compound III as described above, which comprises the following steps: adding sodium pentasulfide into methanol, completely dissolving, and then heating to 25-45℃, and adding dropwise a methanol solution of dibromomethane within 1.5-2.5 hours, slowly stirring for about 30-35 hours; the weight ratio of sodium pentasulfide, methanol, and the methanol solution of dibromomethane is (1-3):(2-5):(3-7), and the concentration of the methanol solution of dibromomethane is 6-12 wt%; adding distilled water to the reaction system, extracting with chloroform, combining the extract, and removing chloroform by normal pressure distillation to obtain the colloidal sulfide-type pentacyclic sulfur compound III.

[0044] In another aspect, the present application provides the use of the high-refractive-index sulfide-type cyclic sulfur compound as described above as a polyurethane optical material.

[0045] The present application has the following advantages:

[0046] (1) The method of the present application has simple synthesis process, mild reaction conditions, and good controllability, and the production equipment required has no special customization requirement, and now the conventional equipment can meet the needs of the synthesis process, which to some extent reduces the cost of application.

[0047] (2) The polymeric monomer includes a novel high-refractive-index sulfide-type cyclic sulfur compound, which has high purity, low color, and good homopolymerization and copolymerization performance, and the highly cross-linked network formed in the polymerization process limits the crystallization of the groups, thereby ensuring the high transparency of the polyurethane material.

[0048] (3) The optical material prepared by the present application has the advantages of high transmission ratio, high refractive index, and low color. BRIEF DESCRIPTION OF DRAWINGS

[0049] Fig. 1 is an FT-IR infrared spectrum of the tricyclic sulfur compound monomer (i) prepared in the specific embodiment.

[0050] Fig. 2 is an HNMR hydrogen nuclear magnetic resonance spectrum of the tricyclic sulfur compound monomer (i) prepared in the specific embodiment.

[0051] Fig. 3 is an FT-IR infrared spectrum of the tetracyclic sulfur compound monomer (ii) prepared in the specific embodiment.

[0052] Fig. 4 is an FT-IR infrared spectrum of the pentacyclic sulfur compound monomer (iii) prepared in the specific embodiment.

[0053] Fig. 5 is a refractive index curve of the sulfide-type cyclic sulfur compound prepared in the specific embodiment. DETAILED DESCRIPTION

[0054] The present application will be further described below through specific embodiments, but this does not mean to limit the scope of protection of the present application.

[0055] The monocyclic sulfur compound in the following examples is prepared by the following method:

[0056] 1. Preparation of tricyclic sulfur compound (i):

[0057] The specific reaction formula is as follows:

[0058] R, R1 is phenyl

[0059] Into a reaction vessel, 900 g of 1,3-diphenylacetone and 1680 g of anhydrous ethanol are added, and after being stirred uniformly, dry hydrogen sulfide and hydrogen chloride gas are introduced for 6 h, with the reaction temperature controlled at 2°C. After 10 h, the precipitate is dried under vacuum to obtain the mercaptan intermediate. 240 g of the mercaptan intermediate and 150 g of benzaldehyde are added to 25000 g of an ethyl ether solvent, and 24 g of p-toluenesulfonic acid is further added. After being stirred at room temperature for 9 h, a saturated sodium chloride solution is added, and after being stirred and separated, the upper layer of light yellow ethyl ether is removed, dried, and decolorized with 150 mesh attapulgite adsorbent to become transparent. The ethyl ether solvent is evaporated to obtain 149 g of tricyclic sulfur compound (i) with a yield of 61.3%.

[0060] The infrared spectrum is shown in Figure 1, and the FT-IR (cm -1 ) analysis: 3060-3031 is the benzene ring C-H stretching vibration; 2902 is the saturated C-H stretching vibration; 1601-1492 is the benzene ring C=C skeleton stretching vibration; 1489 is the CH2 scissors vibration; 745-697 is the out-of-plane deformation vibration of adjacent multiple H atoms =C-H on the benzene ring and the ring skeleton deformation vibration; 579 is the C-S stretching vibration.

[0061] The HNMR nuclear magnetic resonance hydrogen spectrum is shown in Figure 2, 1 The H NMR (δ) analysis: 7.32 (m, 20H, Ar-H), 2.72 (s, 4H, CH2), δ = 7.24-7.34 ppm, of which δ = 7.32 ppm exists 20 hydrogen atoms (Ar-H), which are on the benzene ring and show multiple peaks (m); δ = 4.57 ppm corresponds to one hydrogen connected to the sulfur heterocycle in the tricyclic sulfur compound molecule, which is a single peak due to the absence of hydrogen atoms on the adjacent carbon; δ = 2.72 ppm is the hydrogen on the saturated carbon atom, which shows a single peak (S) and belongs to the hydrogen on the methylene group (CH2), with a quantity of 4.

[0062] 2. Preparation of tetracyclic sulfur compound (ii):

[0063] The specific reaction formula is as follows:

[0064] The thiol intermediate 360g prepared in the above step was added into 1080 ethanol, after dissolution, 820g ferric chloride, 650g water were added, repeatedly stirred, the temperature was controlled at 5°C, reacted for 4.5h, the collected precipitate was recrystallized with n-hexane, vacuum dried to obtain the tetra-cyclic sulfur compound (ii) 186g, the yield was 51.5%.

[0065] The infrared spectrum is shown in Figure 3, FT-IR (cm -1 ) analysis: 3055~3026 is benzene ring C-H stretching vibration; 2909 is saturated C-H stretching vibration; 1603~1556 is benzene ring C=C skeleton stretching vibration; 1490 is benzene ring C=C stretching vibration; 1450 is CH2scissors vibration; 749~706 is the out-of-plane deformation vibration of adjacent 5 H atoms on the benzene ring =C-H and ring skeleton deformation vibration; 587 is C-S stretching vibration; 508 is S-S stretching vibration.

[0066] 1 HNMR (δ) analysis: 7.37 (m, 20H, Ar-H), 2.6 (s, 8H, CH2).

[0067] 3. Preparation of pentacyclic sulfur compound (iii):

[0068] The specific reaction process is as follows:

[0069] 2200g sodium sulfide was dissolved in 11000g anhydrous ethanol, 2400g carbon disulfide was added, and the reaction was stirred at room temperature. 160g of sulfur was added, and the microwave was reacted at 45°C for 50min. It was naturally cooled to room temperature, and n-pentane solvent was added to precipitate sodium pentasulfide. 1050g of sodium pentasulfide was added to 2400g of methanol, dissolved, heated to 35°C, and 5200g of 8% methanol solution of dibromomethane was added dropwise within 2h. After stirring for 31h, distilled water was added, extracted with chloroform, combined, dried with anhydrous sodium sulfate, and the chloroform was removed by atmospheric distillation to obtain pentacyclic sulfur compound (iii) 318g, the yield was 45.4%.

[0070] The infrared spectrum is shown in Figure 4, FT-IR (cm -1 ) analysis: 2955~2887 is C-H stretching vibration peak, 1380~1183 is ring CH2non-planar rocking absorption peak; 809~596 is C-S stretching vibration strong absorption peak; 460 is S-S weak vibration absorption peak.

[0071] 1 HNMR (δ) analysis: 4.30 (s, 4H, 2CH2), the compound has a single peak at δ=4.30ppm, indicating that the two CH2are in the same chemical environment, indicating that the compound structure is symmetrical.

[0072] Example 1: Preparation of polyurethane optical material containing tricyclic sulfur compound monomer (i)

[0073] (1) 20 g of isothiocyanate compound (Hunan Yunbang Biological Technology Co., Ltd., product code: YB06161, the same in the following examples) was heated to 85°C, then 15 g of xylene diisocyanate was added with stirring, and then 0.6 g of triethyldiamine was added. After stirring, a mixture was obtained.

[0074] (2) 65 g of the tricyclic sulfur compound (i) prepared above was added to the mixture prepared in step (1) above, and 1.6 g of dibutyltin dilaurate was added to the reaction mixture. The mixture was heated to 45°C and stirred for 35 min to pre-polymerize. The bubbles were removed under vacuum, and the mixture was injected into a lens mold.

[0075] (3) The mold containing the pre-polymer was placed in a curing oven at 45°C for 3 h, then gradually increased to 85°C, and continued to be placed for 3 h. Finally, it was cooled to room temperature and demolded to obtain a high-refractive polyurethane optical material.

[0076] Example 2: Preparation of polyurethane optical material containing tricyclic sulfur compound (i)

[0077] (1) 20 g of isothiocyanate compound was heated to 65°C, then 5 g of xylene diisocyanate was added with stirring, and then 0.4 g of triethyldiamine was added. After stirring, a mixture was obtained.

[0078] (2) 30 g of the tricyclic sulfur compound (i) prepared above was added to the mixture prepared in step (1) above, and 0.9 g of dibutyltin dilaurate was added to the reaction mixture. The mixture was heated to 50°C and stirred for 35 min to pre-polymerize. The bubbles were removed under vacuum, and the mixture was injected into a lens mold.

[0079] (3) The mold containing the pre-polymer was placed in a curing oven at 45°C for 3 h, then gradually increased to 85°C, and continued to be placed for 3 h. Finally, it was cooled to room temperature and demolded to obtain a high-refractive polyurethane optical material.

[0080] Example 3: Preparation of polyurethane optical material containing tricyclic sulfur compound (i)

[0081] (1) 30 g of the tricyclic sulfur compound (i) prepared above was added to 19 g of xylene diisocyanate, and the mixture was stirred to obtain a reaction mixture.

[0082] (2) 0.7 g of dibutyltin dilaurate was added to the reaction mixture prepared in step (1) above, and the mixture was heated to 45°C and stirred for 35 min to pre-polymerize. The bubbles were removed under vacuum, and the mixture was injected into a lens mold.

[0083] (3) The mold containing the prepolymer is heated in a curing oven at 45°C for 3 hours, then gradually increased to 85°C, and kept for another 3 hours, and finally cooled to room temperature to remove the mold, to obtain the high-refractive polyurethane optical material.

[0084] Example 4: Preparation of polyurethane optical material containing tetra-cyclic sulfur compound (ii)

[0085] (1) 12 g of isothiocyanate compound is heated to 85°C, then 15 g of xylene diisocyanate is added with stirring, and 0.2 g of triethyl diamine is added, and the mixture is stirred uniformly;

[0086] (2) 45 g of the tetra-cyclic sulfur compound (ii) prepared above is added to the mixture prepared in the above step (1), and 1.1 g of dibutyl tin dilaurate is added to the reaction mixture, which is heated to 45°C and kept for 35 minutes of pre-polymerization with stirring, and the bubbles are removed by vacuum, and then injected into the lens mold;

[0087] (3) The mold containing the prepolymer is heated in a curing oven at 45°C for 3 hours, then gradually increased to 85°C, and kept for another 3 hours, and finally cooled to room temperature to remove the mold, to obtain the high-refractive polyurethane optical material.

[0088] Example 5: Preparation of polyurethane optical material containing tetra-cyclic sulfur compound (ii)

[0089] (1) 15 g of isothiocyanate compound is heated to 65°C, then 5 g of xylene diisocyanate is added with stirring, and 0.4 g of triethyl diamine is added, and the mixture is stirred uniformly;

[0090] (2) 30 g of the tetra-cyclic sulfur compound (ii) prepared above is added to the mixture prepared in the above step (1), and 0.9 g of dibutyl tin dilaurate is added to the reaction mixture, which is heated to 50°C and kept for 35 minutes of pre-polymerization with stirring, and the bubbles are removed by vacuum, and then injected into the lens mold;

[0091] (3) The mold containing the prepolymer is heated in a curing oven at 45°C for 3 hours, then gradually increased to 85°C, and kept for another 3 hours, and finally cooled to room temperature to remove the mold, to obtain the high-refractive polyurethane optical material.

[0092] Example 6: Preparation of polyurethane optical material containing tetra-cyclic sulfur compound (ii)

[0093] (1) 45 g of the tetra-cyclic sulfur compound (ii) prepared above is added to 19 g of xylene diisocyanate, and the mixture is stirred uniformly to obtain a reaction mixture;

[0094] (2) 0.7 g of dibutyl tin dilaurate is added to the reaction mixture prepared in the above step (1), which is heated to 45°C and kept for 35 minutes of pre-polymerization with stirring, and the bubbles are removed by vacuum, and then injected into the lens mold;

[0095] (3) The mold containing the prepolymer is placed in a curing oven at 45°C for 3 h, then gradually increased to 85°C, and continued to be placed for 3 h, and finally cooled to room temperature to demold, to obtain the high-refractive polyurethane optical material.

[0096] Example 7: Preparation of polyurethane optical material containing pentacyclic sulfur compound (iii)

[0097] (1) 20 g of isothiocyanate compound is heated to 85°C, then 15 g of xylene diisocyanate is added, and 0.6 g of triethyldiamine is added, and the mixture is stirred uniformly.

[0098] (2) 65 g of the pentacyclic sulfur compound (iii) prepared in the above step (1) is added to the mixture prepared in the above step (1), 1.6 g of dibutyltin dilaurate is added to the reaction product, heated to 45°C, and pre-polymerized for 35 min with stirring, and the bubbles are removed in vacuum, and then injected into a lens mold.

[0099] (3) The mold containing the prepolymer is placed in a curing oven at 45°C for 3 h, then gradually increased to 85°C, and continued to be placed for 3 h, and finally cooled to room temperature to demold, to obtain the high-refractive polyurethane optical material.

[0100] Example 8: Preparation of polyurethane optical material containing pentacyclic sulfur compound (iii)

[0101] (1) 30 g of pentacyclic sulfur compound (iii) is heated to 50°C, then 15 g of methanedithiol is added, and the mixture is stirred uniformly.

[0102] (2) The mixture prepared in the above step (1) is added to 20 g of isothiocyanate compound, 0.6 g of triethyldiamine and 0.9 g of dibutyltin dilaurate are added to the reaction product, heated to 50°C, and pre-polymerized for 35 min with stirring, and the bubbles are removed in vacuum, and then injected into a lens mold.

[0103] (3) The mold containing the prepolymer is placed in a curing oven at 45°C for 3 h, then gradually increased to 85°C, and continued to be placed for 3 h, and finally cooled to room temperature to demold, to obtain the high-refractive polyurethane optical material.

[0104] Example 9: Preparation of polyurethane optical material containing pentacyclic sulfur compound (iii)

[0105] (1) 30 g of pentacyclic sulfur compound (iii) prepared in the above step is added to 20 g of xylene diisocyanate, and the reaction product is stirred uniformly.

[0106] (2) Add 0.7g of dibutyltin dilaurate to the reactant prepared in step (1) above, heat to 45°C and stir for 35 min to prepolymerize, remove bubbles under vacuum and inject into the lens mold;

[0107] (3) 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 the high-refractive-index polyurethane optical material.

[0108] Example 10: Preparation of polyurethane optical materials containing pentacyclic sulfur compound (iii)

[0109] (1) Heat 30g of pentacyclic sulfur compound (iii) to 50°C, add 0.5g of toluene solvent, and stir until homogeneous to obtain a mixture;

[0110] (2) After heating 20g of isothiocyanate compound to 75°C, stir and add 0.3g of triethyldiamine, and then add the mixture prepared in step (1) above to obtain the reactant;

[0111] (3) Add 0.6g of dibutyltin dilaurate to the reactant prepared in step (2), heat to 50°C and stir for 35 minutes to prepolymerize, remove bubbles under vacuum and inject into the lens mold;

[0112] (4) 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 it for 3 hours. Finally, cool it to room temperature and demold to obtain the high-refractive-index polyurethane optical material.

[0113] Example 11: Optical performance testing experiment on polyurethane optical materials

[0114] The optical properties of the polyurethane optical materials prepared in Examples 1-10 were tested. Transmittance is one of the most important properties of optical materials, expressed as transmittance. The transmittance was measured using a UV-8000 ultraviolet-visible spectrophotometer from Shanghai Yuanxi Instrument Co., Ltd. The method was to directly place the sample on the UV-visible spectrophotometer to measure the transmittance. Refractive index was measured using a WZS1 Abbe refractometer from Shanghai Optical Instrument Equipment Co., Ltd. The method was as follows: ① The thioether-type cyclic sulfur compound prepared in the specific embodiments was diluted with diethyl ether solvent and coated onto the prism of the Abbe refractometer. After the solvent evaporated, the test results were recorded. ② The refractive index of the polyurethane optical material samples prepared in Examples 1-10 was measured by placing them on the prism of the Abbe refractometer. The test results are shown in Figure 5, Table 1, and Table 2.

[0115] Table 1: Sample Refractive Index Detection Results

[0116] Table 2 shows the optical performance of the tested samples.

[0117] Example 12: Anti-aging test of polyurethane optical material

[0118] The polyurethane optical materials prepared in Examples 1-10 were subjected to anti-aging test respectively, using a water-cooled xenon lamp test chamber of Shanghai Dianuo Technology Company, selecting extreme light conditions, irradiating in the anti-aging test chamber for 32 hours, and detecting the visible light spectral transmittance (tv) and yellow index (IY) of the sample before and after irradiation. The detection results are shown in Table 3.

[0119] Table 3: Anti-aging test situation table of example sample

[0120] Conclusion: Through data comparison, it is known that the test sample of the example does not change obviously.

Claims

1. A high refractive index polyurethane optical material, characterized by, It is polymerized by high refractive index sulfide type ring sulfur compound and isothiocyanate compound and / or isocyanate compound; wherein, the mass ratio of high refractive index sulfide type ring sulfur compound and isothiocyanate compound, isocyanate compound or mixture thereof is (30-70):(10-50); The thioether-type episulfide compound is selected from at least one of the following compounds of Formula I, Formula II, and Formula III: wherein R and R1are the same or different, each being H or CH3or C6H5; Wherein R is H or CH3.

2. The high refractive index polyurethane optical material of claim 1, wherein, The isothiocyanate compound is aliphatic polyisothiocyanate compound or alicyclic polyisothiocyanate compound containing two or more isothiocyanate groups in the molecular structure; The isocyanate compound is a compound containing two or more isocyanate groups in the molecular structure.

3. The high refractive index polyurethane optical material of claim 2, wherein The isothiocyanate compound is selected from at least one of lysine methyl ester diisothiocyanate, lysine triisothiocyanate, hexamethylene diisothiocyanate, m-xylylene diisothiocyanate, bis-isothiocyanato-methyl sulfide, bis-isothiocyanato-ethyl sulfide, bis-isothiocyanato-ethyl disulfide, bis-isothiocyanato-cyclohexane, isophorone diisothiocyanate, dicyclohexylmethane diisothiocyanate, cyclohexane diisothiocyanate, methylcyclohexane diisothiocyanate, bis-isothiocyanato-heptane and bis-isothiocyanato-tricyclodecane; The isocyanate compound is selected from at least one of isophorone diisocyanate trimer, toluene diisocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate trimer, xylene diisocyanate, isophorone diisocyanate, phenylene diisocyanate, cyclohexane diisocyanate and diphenylmethane diisocyanate.

4. The method for preparing the high refractive index polyurethane optical material according to any one of claims 1-3, characterized in that, The method comprises the following steps: (1) one of the sulfide type ring sulfur compound or mixture thereof is mixed with isothiocyanate compound or isocyanate compound or mixture thereof in a weight ratio of (30-70):(10-50); (2) adding a polymerization catalyst to the reactants obtained in step (1) above, pre-polymerizing at 50-80℃ for 10-60min, removing gas bubbles under vacuum, and injecting into a lens mold; (3) placing the mold containing the prepolymer in a curing oven at 35-55℃ for 2-10h, then gradually increasing to 80-100℃, continuing to place for 2-3h, and finally cooling to room temperature to demold, obtaining high-refraction polyurethane optical material.

5. The production method according to claim 4, wherein The step (1) further comprises adding a thiol compound with a refractive index of 1.60-1.85 to the obtained mixture, and the amount of thiol added is 30-65%.

6. The production method according to claim 5, wherein The thiol is selected from at least one of methanedithiol, ethanedithiol, methyl mercaptan, dimercaptomethane, dimercaptoethane, dimercaptopropane, trimercaptopropane, pentaerythritol, bis-mercapto-methyl benzene and bis-mercapto-ethyl sulfide.

7. The production method according to claim 4, wherein The step (1) further comprises adding a solvent, which is one of methanol, ethanol, propanol, dichloroethane, methyl ketone, ethyl ketone, acetone and toluene, xylene, chloroform, chlorobenzene, diethyl ether, dioxane, tetrahydrofuran, and the amount of solvent is 0.5-3wt% of the reactants.

8. The production method according to any one of claims 4 to 7, wherein The polymerization catalyst is one or mixture of triethylenediamine, dimethylthiophenyl diamine, dibutyltin dilaurate, stannous isooctoate, and the amount of catalyst is 1-3wt% of the prepolymer.

9. A high refractive index thioether-type episulfide compound, characterized by, The structure of this compound is shown in formula I: wherein R and R1 are the same or different, each being H, CH3 or C6H5.

10. The method for preparing the high refractive index sulfide-type cyclic sulfide compound I as described in claim 9, characterized in that, The method comprises the following steps: (1) 1,3-diphenylacetone and anhydrous ethanol are added into a reaction container in a weight ratio of (1-3):(3-7), stirred uniformly, and dry hydrogen sulfide and hydrogen chloride gases are introduced in sequence for 3-7 h, with the reaction temperature controlled at 0-6°C. After 10-12 h, the precipitate is dried in vacuum to obtain a thiol intermediate; (2) The thiol intermediate, benzaldehyde and diethyl ether are mixed thoroughly in a weight ratio of (1-2):(1-2):(100-150), and a catalyst is added in an amount of 1 / 8-1 / 12 of the weight of the thiol intermediate. After the reaction is stopped after thorough stirring at room temperature for 7-10 h, a saturated sodium chloride solution is added, and after stirring and mixing, the upper diethyl ether layer is taken out, dried, decolorized with a bentonite adsorbent to be colorless and transparent, and diethyl ether solvent is removed by distillation to obtain a viscous thioether type tricyclic sulfur compound I. The catalyst is one of hydrochloric acid, sulfuric acid, toluenesulfonic acid and p-toluenesulfonic acid.

11. A high refractive index thio-epoxide cyclic sulfur compound characterized in that, The structure of this compound is shown in formula II:

12. The method of producing high refractive index thioether-type episulfide compounds II according to claim 11, characterized in that, The method comprises the following steps: (1) 1,3-diphenylacetone and anhydrous ethanol are added into a reaction container in a weight ratio of (1-3):(3-7), stirred uniformly, and dry hydrogen sulfide and hydrogen chloride gases are introduced in sequence for 3-7 h, with the reaction temperature controlled at 0-6°C. After 10-12 h, the precipitate is dried in vacuum to obtain a thiol intermediate; (2) Anhydrous ethanol and the thiol intermediate are added into the reaction container, and after being dissolved thoroughly, 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). After being stirred thoroughly at 0-10°C for 4-6 h, white powder-like substances are precipitated, and after being filtered, the crude product is recrystallized with n-hexane and dried in vacuum to obtain a thioether type tetracyclic sulfur compound II.

13. A high refractive index thioether-type episulfide compound, characterized by, The structure of this compound is shown in formula III: wherein R is H or CH3.

14. The method of claim 13, wherein the high refractive index thioether-type episulfide compound III is prepared by the process comprising: ###00006### III The method comprises the following steps: sodium pentathio-carbonate is added into methanol, and after being dissolved completely, the temperature is raised to 25-45°C, and methyl bromoformate methanol solution is added dropwise within 1.5-2.5 h, and the reaction is stirred slowly for about 30-35 h. The weight ratio of sodium pentathio-carbonate, methanol and methyl bromoformate methanol solution is (1-3):(2-5):(3-7), and the concentration of the methyl bromoformate methanol solution is 6-12 wt%. Distilled water is added into the reaction system, and chloroform is extracted, and the combined extract is subjected to normal pressure distillation to remove chloroform, and a colloidal thioether type pentacyclic sulfur compound III is obtained.

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