Environment-friendly mercaptan optical resin material and preparation method thereof

Abstract

The invention belongs to the technical field of optical materials, and particularly relates to an environment-friendly mercaptan optical resin material and a preparation method thereof. Comprising the following steps: (1) uniformly mixing a catalyst, a release agent and a polyisocyanate compound to prepare a mixture; (2) adding titanium dioxide nanoparticles with different particle sizes, which are modified by a polythiol compound and a sulfydryl silane coupling agent, into the mixture; and (3) heating and curing to prepare the environment-friendly mercaptan optical resin material. On the basis of small-particle-size titanium dioxide, a small amount of large-particle-size titanium dioxide is added. The large-particle-size titanium dioxide is not prone to agglomeration and good in dispersity, in the blending process, the granular large-particle-size titanium dioxide is easier to disperse, and agglomeration of small-particle-size titanium dioxide is prevented. Due to the addition of the small-particle-size titanium dioxide and the large-particle-size titanium dioxide, the mechanical strength of the mercaptan optical resin is further improved on the basis of maintaining the high refractive index of the mercaptan optical resin.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of optical materials, and particularly relates to an environmentally-friendly thiol optical resin material and a preparation method thereof. BACKGROUND

[0002] Micro-nano manufacturing technology is the core foundation and support for the development of new generation information technology, high-end equipment manufacturing and new material industry. Micro-nano structure manufacturing technology can realize large-area micron-level patterning manufacturing, and is one of the key processes for realizing high-density, low-cost mass production of micro-nano devices and products. In recent years, with the development of micro-nano structure processing technology, many new micro-nano structures have appeared in the field of functional integrated devices. These micro-nano structures have the characteristics of single atomic layer thickness and multi-dimensional size, and play an important role in different fields. With the development of nano manufacturing technology, the requirements for processing precision, processing efficiency and processing quality are also increasing. At present, some new micro-nano structures can be applied to the fields of sensors and optical communication devices. Large-area nanoimprint has very mature facilities and technology in the production of wafer-level micro-nano optical devices, such as optical diffraction elements and optical diffusion sheets in the field of mobile phone lenses. Due to the performance requirements of optical devices, it is an important link in the production chain to prepare high-performance optical materials. At present, there are mainly two kinds of optical materials on the market: inorganic and organic materials. Inorganic optical materials have excellent mechanical properties, high Abbe number, high refractive index and low dispersion, and can be used to make optical devices with small thermal expansion coefficient, good heat resistance and stable optical performance. However, inorganic materials still have some problems in development and application, such as high cost, difficult processing and forming, and difficulty in mass production. Therefore, many material development companies turn to more portable and easier-to-produce organic optical materials, hoping that organic optical materials will have better performance in weather resistance, heat resistance and high refractive index.

[0003] At present, polyurethane is a plastic with a high usage in the world. Due to its high refractive index, good adhesion strength, excellent biocompatibility and high hardness, polythio urethane (thiol optical resin) has great potential in many fields such as lenses, optical fibers, high-grade coatings and medical technology. In addition, due to the presence of hydrogen bonds in its structure, polyurethane materials have excellent mechanical properties. At present, one of the most widely used methods for synthesizing polythio urethane is the nucleophilic addition of thiol to isocyanate catalyzed by base, in addition to the interfacial condensation reaction between diamine and dichlorothioformate derivative and the reaction with cyclic thio carbamate.

[0004] However, the all-round application in the field of optics makes some intrinsic materials unable to meet the requirements, so high-performance organic-inorganic nanocomposites are widely studied, but the incompatibility between inorganic particles and polymer matrix still cannot be effectively solved, resulting in poor material processability, mechanical properties or optical transmittance. SUMMARY

[0005] The current polythiourethane resin preparation process is complex and high in cost, although the addition of nano-titanium dioxide can improve the refractive index of the resin, but the nano-titanium dioxide is easy to agglomerate, and the compatibility between the nano-titanium dioxide and the thiol optical resin matrix is poor, resulting in poor mechanical strength and reduced refractive index of the final product.

[0006] To solve the above problems, the technical scheme of the present application is as follows: The preparation method of the environment-friendly thiol optical resin material comprises the following steps: (1) The catalyst, the release agent and the polyisocyanate compound are mixed uniformly in advance to prepare a mixture; (2) The polythiol compound and the mercapto silane coupling agent modified titanium dioxide nanoparticles are added to the mixture, and the mixture is mixed uniformly and degassed to obtain a monomer mixture; the titanium dioxide nanoparticles are composed of small-particle-size titanium dioxide with an average particle size of less than or equal to 50 nm and large-particle-size titanium dioxide with an average particle size of less than or equal to 150 nm; wherein the average particle size of the large-particle-size titanium dioxide is at least 50 nm larger than that of the small-particle-size titanium dioxide, and the mass ratio of the large-particle-size titanium dioxide to the small-particle-size titanium dioxide is 0.4%-4%; (3) The monomer mixture is injected into a mold, and is heated and cured to obtain the environment-friendly thiol optical resin material.

[0007] The thiol optical resin, i.e. polythiourethane resin, is widely used in various resin lenses, building material coatings, precision lenses, optical fibers and functional coatings due to its impact resistance, dyeability, easy processing, light weight and excellent optical properties. However, the refractive index and mechanical properties of the thiol optical resin are low, so introducing inorganic nanoparticles with high refractive index and high strength into the thiol optical resin is a common method to improve its optical properties and mechanical properties. Titanium dioxide has a high refractive index and certain antibacterial properties, and is the most commonly used nanoparticle in optical resin. Generally speaking, the greater the content of uniformly dispersed nano-titanium dioxide particles, the higher the refractive index and mechanical strength of the composite material. However, due to the small particle size of inorganic nano-titanium dioxide particles, the surface free energy is large, and the nanoparticles are prone to aggregation, and the dispersion of the nanoparticles in the resin matrix and the interfacial interaction between the nanoparticles and the resin affect the improvement of the optical properties and mechanical properties. Moreover, excessive nano-titanium dioxide particles reduce the transparency of the material and the processability of the organic matrix. Therefore, a technical solution balancing the relationship between mechanical strength and optical properties is urgently needed.

[0008] The present application uses a blending method to improve the optical properties and mechanical strength of the thiol resin. Compared with in-situ polymerization and sol-gel methods, the blending method is simpler, the cost is reduced, and various toxic and harmful substances do not need to be added, which meets the needs of environmental protection development.

[0009] In order to let the nano-titanium dioxide particles be uniformly dispersed in the matrix, the prevention of agglomeration is not conducive to the improvement of optical performance and mechanical strength. The present application selects different particle sizes (volume average particle size D50) of titanium dioxide: the titanium dioxide nanoparticles are composed of small particle size titanium dioxide with an average particle size of less than or equal to 50 nm and large particle size titanium dioxide with an average particle size of less than or equal to 150 nm; wherein the average particle size of the large particle size titanium dioxide is at least 50 nm larger than the average particle size of the small particle size titanium dioxide, and the mass ratio of the large particle size titanium dioxide to the small particle size titanium dioxide is 0.4%-4%, in particular, 0.6%-2%. Further, the average particle size of the large particle size titanium dioxide is 100-150 nm. In particular, for a single particle, the particle size of the small particle size titanium dioxide can be 1-100 nm, and the particle size of the large particle size titanium dioxide is less than 200 nm. Further, both the small particle size titanium dioxide and the large particle size titanium dioxide are monodisperse, with a distribution index PDI less than 0.3, further less than 0.1, and more further less than 0.05.

[0010] Generally speaking, the smaller the particle size of titanium dioxide, the smaller the influence on the transparency of the optical resin; however, the smaller the particle size, the greater the surface energy, and the more likely the agglomeration tendency, and the agglomerated nano-titanium dioxide is not conducive to the improvement of the mechanical and optical properties of the optical resin. Therefore, the present application adds a small amount of large particle size titanium dioxide on the basis of small particle size titanium dioxide. The large particle size titanium dioxide is not easy to agglomerate and has good dispersibility, and during the blending process, the particulate large particle size titanium dioxide is easier to disperse and can act as a "separation pile" for the small particle size titanium dioxide to prevent agglomeration of the small particle size titanium dioxide. As a solid dispersion aid, the amount of large particle size titanium dioxide should not be too high, otherwise it is not conducive to the improvement of the performance of the resin.

[0011] Meanwhile, in order to improve the interface performance, the surface of the titanium dioxide nanoparticles is modified by a small amount of thiol silane coupling agent with reactive active groups, so that the combination performance of the titanium dioxide inorganic nanoparticles and the matrix is improved, and an organic-inorganic nanocomposite material with more excellent performance is prepared. Generally speaking, for the preparation of high refractive index organic-inorganic nanocomposite material, it is necessary to modify the surface of the nanoparticles, and if the combination between the nanoparticles and the polymer is poor, the mechanical properties and optical properties of the material are easily lost. In addition, the active hydroxyl groups remaining on the surface of the nanometer titanium dioxide can also react with the isocyanate groups, thereby promoting the connection between the nanometer titanium dioxide particles and the organic polymer matrix, and enhancing the stability of the material skeleton. Moreover, due to the strong covalent connection between the nanometer titanium dioxide and the thiol optical resin, the chemical bonding limits the internal rotation of the surrounding polymer chain segments, so that the chain segment movement is more difficult, thereby enhancing the mechanical properties of the polymer material. At the same time, the existence of nanometer titanium dioxide provides a stress concentration area for the material, and the strong interface bonding between the thiol optical matrix is beneficial to the transmission of stress, and the structure is not broken due to the local stress being too high, so that the toughness of the material is enhanced, thereby realizing the enhancement of the mechanical properties of the composite material. The optical properties and mechanical properties of the thiol resin are not only affected by the particle size and amount of nanometer titanium dioxide, but also have a great relationship with the modification of the coupling agent and the combination mode with the matrix resin. The optical resin prepared by the process of the present application can better improve the performance of the composite material.

[0012] Further, the catalyst in step (1) includes one or more of amine compounds or organotin compounds; and the release agent is a phosphate compound.

[0013] Further, the amine compound includes one or more of triethylamine, tributylamine, methylpyridine, and dimethylcyclohexylamine.

[0014] Further, the organotin compound includes one or more of dibutyltin dichloride, dimethyltin dichloride, di-n-octyltin dilaurate, or dibutyltin dilaurate.

[0015] Further, the phosphate compound includes one or more of dibutyl phosphate, dimethylphenyl phosphate, triethyl phosphate, tributyl phosphate, or triphenyl phosphate.

[0016] Further, the polyisocyanate compound in step (1) is one or more of xylylene diisocyanate, toluene diisocyanate, dicyclohexylmethane diisocyanate, cyclohexane dimethylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dimethylpentane diisocyanate, trimethylhexane diisocyanate, butene diisocyanate, and hexamethylene triisocyanate.

[0017] Further, the mass ratio of the catalyst, the release agent, and the polyisocyanate compound in step (1) is 0.05-1:0.1-10:1000.

[0018] Further, the polybasic mercaptan compound in step (2) is one or more of methanedithiol, ethanedithiol, propanedithiol, hexanedithiol, cyclohexanedithiol, propanetriol, pentaerythritol tetra(3-mercaptopropionate), trimethylolpropane tri(3-mercaptopropionate), tetra(3-mercaptobutyrate) pentaerythritol, 2,3-dithia(2-mercapto)-1-propane thiol.

[0019] Further, the mercapto silane coupling agent in step (2) is one or more of mercaptopropyl trimethoxysilane, mercaptopropyl triethoxysilane, mercaptopropyl methyldimethoxysilane, mercaptopropyl methyldiethoxysilane, mercaptomethyl methyldiethoxysilane.

[0020] Further, the molar ratio of -SH in the polybasic mercaptan compound and -NCO in the polyisocyanate compound in step (2) is 1:1.1-1.15.

[0021] Further, the average particle size of the small-particle-size titanium dioxide in step (2) is 25-50 nm; and the mass ratio of the sum of the mass of the small-particle-size titanium dioxide and the mass of the large-particle-size titanium dioxide to the sum of the mass of the polyisocyanate compound and the mass of the polybasic mercaptan compound is 0.001%-5%. The average particle size of the small-particle-size nano-titanium dioxide is not particularly limited, and common values are 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, and 50 nm. If the particle size is too small, it is difficult to prepare and easy to agglomerate; if the particle size is too large, the quantum size effect of the inorganic nano-particle cannot be exerted, and the mechanical properties of the mercaptan optical resin cannot be effectively improved. In particular, the large-particle-size titanium dioxide can be added first, mixed uniformly, and then the small-particle-size titanium dioxide is added, so as to better exert the isolation effect of the large-particle-size titanium dioxide. Further, the mass ratio of the sum of the mass of the small-particle-size titanium dioxide and the mass of the large-particle-size titanium dioxide to the sum of the mass of the polyisocyanate compound and the mass of the polybasic mercaptan compound can be 0.001%, 0.01%, 0.1%, 1%, 2%, 3%, 4%, or 5%. In particular, the mass ratio of the sum of the mass of the small-particle-size titanium dioxide and the mass of the large-particle-size titanium dioxide to the sum of the mass of the polyisocyanate compound and the mass of the polybasic mercaptan compound is 0.25%-1%. The appropriate amount of nano-titanium dioxide can not only enhance the mechanical properties of the resin, but also avoid the agglomeration of too much inorganic filler, thereby reducing the toughness. In particular, the mixing process in step (2) can use ultrasonic technology to promote the dispersion of the titanium dioxide.

[0022] Further, the average particle size of the large-particle-size titanium dioxide in step (2) is 100-150 nm. If the particle size is too small, it is difficult to play a shielding role, while appropriate particle size can not only play the shielding role of large-particle-size titanium dioxide and prevent the problem of agglomeration of small particle size, but also avoid the problem of easy settlement caused by too large particle size and too small specific surface area, thereby fully playing the role of shielding and dispersion.

[0023] Further, the polythiol compound in step (2) is 2,3-dithio (2-mercapto)-1-propane thiol, and its preparation process is as follows: adding mercaptoethanol into a reactor, then adding sodium hydroxide solution dropwise, and stirring uniformly; then adding epichlorohydrin dropwise, and reacting for 0.5-1 h; adding concentrated hydrochloric acid and thiourea to prepare a salt solution; then alkaline hydrolysis with ammonia water, water washing, and dehydration and separation to obtain 2,3-dithio (2-mercapto)-1-propane thiol. The specific process can also refer to the master's thesis: “2,3-dithio (2-mercapto)-1-propane thiol synthesis and application research”, Zhang Jie, Beijing University of Chemical Technology, 2021.

[0024] Further, the preparation process of the mercapto silane coupling agent modified titanium dioxide nanoparticles in step (2) is as follows: uniformly dispersing small-particle-size titanium dioxide nanoparticles or large-particle-size titanium dioxide nanoparticles in a mixed solvent of ethanol and deionized water, adding mercapto silane coupling agent while stirring, then stirring and reacting for 1-3 h, and filtering, washing, and drying to obtain mercapto silane coupling agent modified small-particle-size titanium dioxide nanoparticles or large-particle-size titanium dioxide nanoparticles. Further, the mass ratio of small-particle-size titanium dioxide nanoparticles or large-particle-size titanium dioxide nanoparticles to mercapto silane coupling agent in step (2) is 1:(0.1-0.3). Specifically, the mass ratio of small-particle-size titanium dioxide nanoparticles or large-particle-size titanium dioxide nanoparticles to mercapto silane coupling agent is 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, or particularly 1:(0.15-0.25). An appropriate amount of mercapto silane coupling agent can not only promote the dispersion of inorganic nanoparticles, but also reduce the influence of the coupling agent on the optical properties of the resin.

[0025] Further, the temperature increasing process in step (3) is heating from 30℃ to 120℃ for 18-22 h.

[0026] Beneficial effects: on the basis of small particle size titanium dioxide, a small amount of large particle size titanium dioxide is added. The large particle size titanium dioxide is not easy to agglomerate and has good dispersibility. Moreover, during the blending process, the granular large particle size titanium dioxide is easier to disperse, and can act as a "isolation pile" for the small particle size titanium dioxide to prevent the agglomeration of the small particle size titanium dioxide. At the same time, in order to improve the interface performance, a small amount of mercapto silane coupling agent is used to modify the surface of the titanium dioxide nanoparticles to improve the bonding performance of the titanium dioxide inorganic nanoparticles and the matrix, and an organic-inorganic nanocomposite material with more excellent performance is prepared. The presence of nanometer titanium dioxide provides a stress concentration area for the material. The strong interface bonding between the thiol optical matrix is conducive to the transmission of stress, and will not cause the structure to break due to excessive local stress, which strengthens the strength and toughness of the material, thereby achieving the mechanical property enhancement of the composite material. The addition of small particle size titanium dioxide and large particle size titanium dioxide further improves the mechanical strength on the basis of maintaining the high refractive index of the thiol optical resin. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below. In the following description, a large number of specific details are set forth in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the scope of the present application, so the present application is not limited to the specific embodiments disclosed below. In the following examples, the types of raw materials and processes used are the same unless otherwise specified.

[0028] The preparation process of the large particle size titanium dioxide nanoparticles modified by the mercapto silane coupling agent and the small particle size titanium dioxide nanoparticles modified by the mercapto silane coupling agent is as follows: uniformly disperse the large particle size titanium dioxide nanoparticles (or small particle size titanium dioxide nanoparticles) into a mixed solvent of ethanol and deionized water, add the mercapto silane coupling agent while stirring, then stir for 2h, filter, wash, and dry to obtain the large particle size titanium dioxide nanoparticles modified by the mercapto silane coupling agent (or the small particle size titanium dioxide nanoparticles modified by the mercapto silane coupling agent).

[0029] Example 1 A preparation method of an environmentally friendly thiol optical resin material, comprising the following steps: (1) The catalyst dibutyltin dichloride, the release agent dibutyl phosphate, and the polyisocyanate compound are mixed uniformly in advance to prepare a mixture; the polyisocyanate compound is a mixture of isophorone diisocyanate and cyclohexane dimethylene diisocyanate at a molar ratio of 1:1.5; the mass ratio of the catalyst, the release agent, the polyisocyanate compound, and the polythiol compound to the sum of the mass of the polyisocyanate compound and the polythiol compound is 0.1:0.8:1000; (2) adding polythiol compound and mercapto silane coupling agent modified large particle size titanium dioxide nanoparticles into the mixture, mixing uniformly, then adding mercapto silane coupling agent modified small particle size titanium dioxide nanoparticles, mixing uniformly again, degassing, to obtain a monomer mixture; the average particle size D50 of the large particle size titanium dioxide is 105 nm, the average particle size D50 of the small particle size titanium dioxide is 25 nm; the mass ratio of the large particle size titanium dioxide and the small particle size titanium dioxide is 4%; the mercapto silane coupling agent is mercaptopropyl trimethoxysilane; the mass ratio of the large particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.24; the mass ratio of the small particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.24; the polythiol compound is 2,3-dithio (2-mercapto)-1-propane thiol; the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.15; the mass ratio of the sum of the mass of the small particle size titanium dioxide and the large particle size titanium dioxide to the sum of the mass of the polyisocyanate compound and the polythiol compound is 0.35%; (3) injecting the monomer mixture into a mold, heating from 30℃ to 120℃ for 18h to cure, to obtain an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested by using an Abbe refractometer and an XJJD-50J impact tester, respectively, and the refractive index is 1.651 and the impact strength is 26.08kJ / m 2 .

[0030] Example 2 A method for preparing an environmentally friendly thiol optical resin material, comprising the following steps: (1) mixing the catalyst dibutyl tin dichloride, the release agent dibutyl phosphate, and the polyisocyanate compound in advance to prepare a mixture; the polyisocyanate compound is a mixture of isophorone diisocyanate and cyclohexane dimethylene diisocyanate at a molar ratio of 1.7:1; the mass ratio of the catalyst, the release agent, and the sum of the mass of the polyisocyanate compound and the polythiol compound is 0.2:1.5:1000; (2) adding polythiol compound and mercapto silane coupling agent modified large particle size titanium dioxide nanoparticles into the mixture, mixing uniformly, then adding mercapto silane coupling agent modified small particle size titanium dioxide nanoparticles, mixing uniformly again, degassing, to obtain a monomer mixture; the average particle size D50 of the large particle size titanium dioxide is 100 nm, the average particle size D50 of the small particle size titanium dioxide is 50 nm; the mass ratio of the large particle size titanium dioxide and the small particle size titanium dioxide is 0.4%; the mercapto silane coupling agent is mercaptopropyl triethoxysilane; the mass ratio of the large particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.1; the mass ratio of the small particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.1; the polythiol compound is 2,3-dithio (2-mercapto)-1-propane thiol; the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.1; the mass ratio of the sum of the mass of the small particle size titanium dioxide and the mass of the large particle size titanium dioxide to the sum of the mass of the polyisocyanate compound and the mass of the polythiol compound is 0.85%; (3) injecting the monomer mixture into a mold, heating from 30℃ to 120℃ for 22h to cure, to obtain an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested by using an Abbe refractometer and an XJJD-50J impact tester, respectively, and the refractive index is 1.681 and the impact strength is 28.11kJ / m 2 .

[0031] Example 3 A method for preparing an environmentally friendly thiol optical resin material, comprising the following steps: (1) mixing a catalyst dibutyl tin dichloride, a release agent dibutyl phosphate, and a polyisocyanate compound in advance to prepare a mixture; the polyisocyanate compound is a mixture of isophorone diisocyanate and hexamethylene diisocyanate at a molar ratio of 1:3; the mass ratio of the catalyst, the release agent, and the sum of the mass of the polyisocyanate compound and the mass of the polythiol compound is 0.15:1.2:1000; (2) adding polythiol compound and mercapto silane coupling agent modified small particle size titanium dioxide nanoparticles into the mixture, mixing uniformly, then adding mercapto silane coupling agent modified large particle size titanium dioxide nanoparticles, mixing uniformly again, degassing, to obtain a monomer mixture; the average particle size D50 of the large particle size titanium dioxide is 110 nm, the average particle size D50 of the small particle size titanium dioxide is 40 nm; the mass ratio of the large particle size titanium dioxide and the small particle size titanium dioxide is 1.7%; the mercapto silane coupling agent is mercaptopropyl trimethoxysilane; the mass ratio of the large particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.18; the mass ratio of the small particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.18; the polythiol compound is 2,3-dithio (2-mercapto)-1-propane thiol; the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.13; the mass ratio of the sum of the mass of the small particle size titanium dioxide and the large particle size titanium dioxide to the sum of the mass of the polyisocyanate compound and the polythiol compound is 0.74%; (3) injecting the monomer mixture into a mold, heating from 30℃ to 120℃ for 20h to cure, to obtain an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested by using an Abbe refractometer and an XJJD-50J impact testing machine, respectively, and the refractive index is 1.664 and the impact strength is 27.37kJ / m 2 .

[0032] Example 4 A method for preparing an environmentally friendly thiol optical resin material, comprising the following steps: (1) mixing the catalyst dibutyl tin dichloride, the release agent dibutyl phosphate, and the polyisocyanate compound in advance to prepare a mixture; the polyisocyanate compound is a mixture of phenylene dimethylene diisocyanate and hexamethylene diisocyanate at a molar ratio of 1:1; the mass ratio of the catalyst, the release agent, and the sum of the mass of the polyisocyanate compound and the polythiol compound is 0.12:1.3:1000; (2) adding polythiol compound and mercapto silane coupling agent modified large particle size titanium dioxide nanoparticles into the mixture, mixing uniformly, then adding mercapto silane coupling agent modified small particle size titanium dioxide nanoparticles, mixing uniformly again, degassing, to obtain a monomer mixture; the average particle size D50 of the large particle size titanium dioxide is 110 nm, the average particle size D50 of the small particle size titanium dioxide is 50 nm; the mass ratio of the large particle size titanium dioxide and the small particle size titanium dioxide is 0.8%; the mercapto silane coupling agent is mercaptopropyl triethoxysilane; the mass ratio of the large particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.1; the mass ratio of the small particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.24; the polythiol compound is 2,3-dithio (2-mercapto)-1-propane thiol; the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.1; the mass ratio of the sum of the mass of the small particle size titanium dioxide and the mass of the large particle size titanium dioxide to the sum of the mass of the polyisocyanate compound and the mass of the polythiol compound is 0.40%; (3) injecting the monomer mixture into a mold, heating from 30℃ to 120℃ for 19h to cure, to obtain an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested by using an Abbe refractometer and an XJJD-50J impact tester, respectively, and the refractive index is 1.657 and the impact strength is 26.43kJ / m 2 .

[0033] Example 5 A method for preparing an environmentally friendly thiol optical resin material, comprising the following steps: (1) mixing the catalyst dibutyl tin dichloride, the release agent dibutyl phosphate, and the polyisocyanate compound in advance to prepare a mixture; the polyisocyanate compound is a mixture of isophorone diisocyanate and hexamethylene diisocyanate at a molar ratio of 1:3; the mass ratio of the catalyst, the release agent, and the sum of the mass of the polyisocyanate compound and the mass of the polythiol compound is 0.15:1.2:1000; (2) adding polythiol compound and mercapto silane coupling agent modified large particle size titanium dioxide nanoparticles into the mixture, mixing uniformly, then adding mercapto silane coupling agent modified small particle size titanium dioxide nanoparticles, mixing uniformly again, degassing, to obtain a monomer mixture; the average particle size D50 of the large particle size titanium dioxide is 110 nm, the average particle size D50 of the small particle size titanium dioxide is 40 nm; the mass ratio of the large particle size titanium dioxide and the small particle size titanium dioxide is 1.7%; the mercapto silane coupling agent is mercaptopropyl trimethoxysilane; the mass ratio of the large particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.18; the mass ratio of the small particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.18; the polythiol compound is 2,3-dithio (2-mercapto)-1-propane thiol; the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.13; the mass ratio of the sum of the mass of the small particle size titanium dioxide and the mass of the large particle size titanium dioxide to the sum of the mass of the polyisocyanate compound and the mass of the polythiol compound is 1.01%; (3) injecting the monomer mixture into a mold, heating from 30℃ to 120℃ for 20h to cure, to obtain an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested by using an Abbe refractometer and an XJJD-50J impact tester, respectively, and the refractive index is 1.675 and the impact strength is 26.31kJ / m 2 .

[0034] Example 6 A method for preparing an environmentally friendly thiol optical resin material, comprising the following steps: (1) mixing the catalyst dibutyl tin dichloride, the release agent dibutyl phosphate, and the polyisocyanate compound in advance to prepare a mixture; the polyisocyanate compound is a mixture of toluene diisocyanate and hexamethylene diisocyanate at a molar ratio of 1:1; the mass ratio of the catalyst, the release agent, and the sum of the mass of the polyisocyanate compound and the mass of the polythiol compound is 0.14:1.0:1000; (2) adding polythiol compound and mercapto silane coupling agent modified large particle size titanium dioxide nanoparticles into the mixture, mixing uniformly, then adding mercapto silane coupling agent modified small particle size titanium dioxide nanoparticles, mixing uniformly again, degassing, to obtain a monomer mixture; the average particle size D50 of the large particle size titanium dioxide is 110 nm, the average particle size D50 of the small particle size titanium dioxide is 45 nm; the mass ratio of the large particle size titanium dioxide and the small particle size titanium dioxide is 1.3%; the mercapto silane coupling agent is mercaptopropyl triethoxysilane; the mass ratio of the large particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.15; the mass ratio of the small particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.18; the polythiol compound is a mixture of trimethylolpropane tris (3-mercaptopropionate) and 2, 3-dithio (2-mercapto) -1-propane thiol with a molar ratio of 1:2; the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.12; the mass ratio of the sum of the mass of the small particle size titanium dioxide and the large particle size titanium dioxide to the sum of the mass of the polyisocyanate compound and the polythiol compound is 0.46%; (3) injecting the monomer mixture into a mold, heating from 30℃ to 120℃ for 19h to cure, to obtain an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested by using an Abbe refractometer and an XJJD-50J impact tester, respectively, and the refractive index is 1.659 and the impact strength is 26.57kJ / m 2 .

[0035] Example 7 A method for preparing an environmentally friendly thiol optical resin material, comprising the following steps: (1) mixing the catalyst dibutyltin dichloride, the release agent dibutyl phosphate, and the polyisocyanate compound uniformly in advance to prepare a mixture; the polyisocyanate compound is a mixture of isophorone diisocyanate and hexamethylene diisocyanate with a molar ratio of 1:3; the mass ratio of the catalyst, the release agent, and the sum of the mass of the polyisocyanate compound and the polythiol compound is 0.15:1.2:1000; (2) adding polythiol compound and mercapto silane coupling agent modified large particle size titanium dioxide nanoparticles into the mixture, mixing uniformly, then adding mercapto silane coupling agent modified small particle size titanium dioxide nanoparticles, mixing uniformly again, degassing, to obtain a monomer mixture; the average particle size D50 of the large particle size titanium dioxide is 110 nm, the average particle size D50 of the small particle size titanium dioxide is 40 nm; the mass ratio of the large particle size titanium dioxide and the small particle size titanium dioxide is 1.7%; the mercapto silane coupling agent is mercaptopropyl trimethoxysilane; the mass ratio of the large particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.3; the mass ratio of the small particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.3; the polythiol compound is 2,3-dithio (2-mercapto)-1-propane thiol; the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.13; the mass ratio of the sum of the mass of the small particle size titanium dioxide and the large particle size titanium dioxide to the sum of the mass of the polyisocyanate compound and the polythiol compound is 0.74%; (3) injecting the monomer mixture into a mold, heating from 30℃ to 120℃ for 20h to cure, to obtain an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested by using an Abbe refractometer and an XJJD-50J impact tester, respectively, and the refractive index is 1.658 and the impact strength is 28.71kJ / m 2 .

[0036] Example 8 A method for preparing an environmentally friendly thiol optical resin material, comprising the following steps: (1) mixing the catalyst dibutyl tin dichloride, the release agent dibutyl phosphate, and the polyisocyanate compound in advance to prepare a mixture; the polyisocyanate compound is a mixture of isophorone diisocyanate and cyclohexane dimethylene diisocyanate at a molar ratio of 2:1; the mass ratio of the catalyst, the release agent, and the sum of the mass of the polyisocyanate compound and the polythiol compound is 0.18:1.3:1000; (2) adding polythiol compound and mercapto silane coupling agent modified large particle size titanium dioxide nanoparticles into the mixture, mixing uniformly, then adding mercapto silane coupling agent modified small particle size titanium dioxide nanoparticles, mixing uniformly again, degassing, to obtain a monomer mixture; the average particle size D50 of the large particle size titanium dioxide is 150 nm, the average particle size D50 of the small particle size titanium dioxide is 35 nm; the mass ratio of the large particle size titanium dioxide and the small particle size titanium dioxide is 2.0%; the mercapto silane coupling agent is mercaptopropyl triethoxysilane; the mass ratio of the large particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.21; the mass ratio of the small particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.21; the polythiol compound is 2,3-dithio (2-mercapto)-1-propane thiol; the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.14; the mass ratio of the sum of the mass of the small particle size titanium dioxide and the mass of the large particle size titanium dioxide to the sum of the mass of the polyisocyanate compound and the mass of the polythiol compound is 0.67%; (3) injecting the monomer mixture into a mold, heating from 30℃ to 120℃ for 21h to cure, to obtain an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested by using an Abbe refractometer and an XJJD-50J impact tester, respectively, and the refractive index is 1.667 and the impact strength is 27.68kJ / m 2 .

[0037] Example 9 A method for preparing an environmentally friendly thiol optical resin material, comprising the following steps: (1) mixing the catalyst dibutyl tin dichloride, the release agent dibutyl phosphate, and the polyisocyanate compound in advance to prepare a mixture; the polyisocyanate compound is a mixture of cyclohexane dimethylene diisocyanate and isophorone diisocyanate at a molar ratio of 1:1; the mass ratio of the catalyst, the release agent, and the sum of the mass of the polyisocyanate compound and the mass of the polythiol compound is 0.2:1.2:1000; (2) adding polythiol compound and mercapto silane coupling agent modified large particle size titanium dioxide nanoparticles into the mixture, mixing uniformly, then adding mercapto silane coupling agent modified small particle size titanium dioxide nanoparticles, mixing uniformly again, degassing, to obtain a monomer mixture; the average particle size D50 of the large particle size titanium dioxide is 130 nm, the average particle size D50 of the small particle size titanium dioxide is 40 nm; the mass ratio of the large particle size titanium dioxide and the small particle size titanium dioxide is 3.2%; the mercapto silane coupling agent is mercaptopropyl triethoxysilane; the mass ratio of the large particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.18; the mass ratio of the small particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.2; the polythiol compound is pentaerythritol tetra(3-mercaptopropionate); the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.13; the mass ratio of the sum of the mass of the small particle size titanium dioxide and the mass of the large particle size titanium dioxide to the sum of the mass of the polyisocyanate compound and the mass of the polythiol compound is 0.52%; (3) injecting the monomer mixture into a mold, heating from 30℃ to 120℃ for 20h to cure, to obtain an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested by using an Abbe refractometer and an XJJD-50J impact testing machine, respectively, and the refractive index is 1.661 and the impact strength is 26.91kJ / m 2 .

[0038] Example 10 A method for preparing an environmentally friendly thiol optical resin material, comprising the following steps: (1) mixing the catalyst dibutyltin dichloride, the release agent dibutyl phosphate, and the polyisocyanate compound in advance to prepare a mixture; the polyisocyanate compound is a mixture of toluene diisocyanate and hexamethylene diisocyanate at a molar ratio of 1:3; the mass ratio of the catalyst, the release agent, and the sum of the mass of the polyisocyanate compound and the mass of the polythiol compound is 0.15:1.2:1000; (2) adding polythiol compound and mercapto silane coupling agent modified large particle size titanium dioxide nanoparticles into the mixture, mixing uniformly, then adding mercapto silane coupling agent modified small particle size titanium dioxide nanoparticles, mixing uniformly again, degassing, to obtain a monomer mixture; the average particle size D50 of the large particle size titanium dioxide is 140 nm, the average particle size D50 of the small particle size titanium dioxide is 30 nm; the mass ratio of the large particle size titanium dioxide and the small particle size titanium dioxide is 1.7%; the mercapto silane coupling agent is mercaptopropyl triethoxysilane; the mass ratio of the large particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.21; the mass ratio of the small particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.18; the polythiol compound is a mixture of trimethylolpropane tris (3-mercaptopropionate) and tetra (3-mercaptobutyric acid) pentaerythritol ester with a molar ratio of 1:1; the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.13; the mass ratio of the sum of the mass of the small particle size titanium dioxide and the large particle size titanium dioxide to the sum of the mass of the polyisocyanate compound and the polythiol compound is 0.7%; (3) injecting the monomer mixture into a mold, heating from 30℃ to 120℃ for 22h to obtain an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested by using an Abbe refractometer and an XJJD-50J impact tester, respectively, and the refractive index is 1.671 and the impact strength is 28.24kJ / m 2 .

[0039] Example 11 A method for preparing an environmentally friendly thiol optical resin material, comprising the following steps: (1) mixing the catalyst dibutyltin dichloride, the release agent dibutyl phosphate, and the polyisocyanate compound uniformly in advance to prepare a mixture; the polyisocyanate compound is a mixture of isophorone diisocyanate and hexamethylene diisocyanate with a molar ratio of 1:3; the mass ratio of the catalyst, the release agent, and the sum of the mass of the polyisocyanate compound and the polythiol compound is 0.15:1.2:1000; (2) adding polythiol compound and mercapto silane coupling agent modified large particle size titanium dioxide nanoparticles into the mixture, mixing uniformly, then adding mercapto silane coupling agent modified small particle size titanium dioxide nanoparticles, mixing uniformly again, degassing, to obtain a monomer mixture; the average particle size D50 of the large particle size titanium dioxide is 110 nm, the average particle size D50 of the small particle size titanium dioxide is 40 nm; the mass ratio of the large particle size titanium dioxide and the small particle size titanium dioxide is 1.7%; the mercapto silane coupling agent is mercaptopropyl trimethoxysilane; the mass ratio of the large particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.18; the mass ratio of the small particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.18; the polythiol compound is 2,3-dithio (2-mercapto)-1-propane thiol; the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.13; the mass ratio of the sum of the mass of the small particle size titanium dioxide and the large particle size titanium dioxide to the sum of the mass of the polyisocyanate compound and the polythiol compound is 0.74%; (3) injecting the monomer mixture into a mold, heating from 30℃ to 120℃ for 20h to cure, to prepare an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested by using an Abbe refractometer and an XJJD-50J impact tester respectively, and the refractive index is 1.672 and the impact strength is 28.76kJ / m 2 .

[0040] Comparative Example 1 A preparation method of an environmentally friendly thiol optical resin material, comprising the following steps: (1) mixing a catalyst dibutyl tin dichloride, a release agent dibutyl phosphate and a polyisocyanate compound uniformly in advance to prepare a mixture; the polyisocyanate compound is a mixture of isophorone diisocyanate and hexamethylene diisocyanate at a molar ratio of 1:3; the mass ratio of the catalyst, the release agent, the sum of the mass of the polyisocyanate compound and the mass of the polythiol compound is 0.15:1.2:1000; (2) adding polythiol compound and mercapto silane coupling agent modified large particle size titanium dioxide nanoparticles into the mixture, mixing uniformly, degassing, to obtain a monomer mixture; the average particle size D50 of the large particle size titanium dioxide is 110 nm; the mercapto silane coupling agent is mercaptopropyl trimethoxysilane; the mass ratio of the large particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.18; the polythiol compound is 2,3-dithio (2-mercapto)-1-propane thiol; the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.13; the mass ratio of the large particle size titanium dioxide and the sum of the mass of the polyisocyanate compound and the mass of the polythiol compound is 0.74%; (3) The monomer mixture is injected into a mold, heated from 30℃ to 120℃ for 20h, and temperature-cured to obtain an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested using an Abbe refractometer and an XJJD-50J impact tester, respectively, and the refractive index is 1.638 and the impact strength is 22.32kJ / m 2 .

[0041] Comparative Example 2 A method for preparing an environmentally friendly thiol optical resin material, comprising the following steps: (1) The catalyst dibutyltin dichloride, the release agent dibutyl phosphate, and the polyisocyanate compound are mixed in advance to prepare a mixture; the polyisocyanate compound is a mixture of isophorone diisocyanate and hexamethylene diisocyanate at a molar ratio of 1:3; the mass ratio of the catalyst, the release agent, the polyisocyanate compound, and the polythiol compound is 0.15:1.2:1000; (2) The polythiol compound and the small-particle-size titanium dioxide nanoparticles modified by the mercapto silane coupling agent are added to the mixture, mixed uniformly, and degassed to obtain a monomer mixture; the average particle size D50 of the small-particle-size titanium dioxide is 40nm; the mercapto silane coupling agent is mercaptopropyl trimethoxysilane; the mass ratio of the small-particle-size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.18; the polythiol compound is 2,3-dithio(2-mercapto)-1-propane thiol; the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.13; the mass ratio of the small-particle-size titanium dioxide and the polyisocyanate compound and the polythiol compound is 0.74%; (3) The monomer mixture is injected into a mold, heated from 30℃ to 120℃ for 20h, and temperature-cured to obtain an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested using an Abbe refractometer and an XJJD-50J impact tester, respectively, and the refractive index is 1.646 and the impact strength is 23.47kJ / m 2 .

[0042] Comparative Example 3 A method for preparing an environmentally friendly thiol optical resin material, comprising the following steps: (1) The catalyst dibutyltin dichloride, the release agent dibutyl phosphate, and the polyisocyanate compound are mixed in advance to prepare a mixture; the polyisocyanate compound is a mixture of isophorone diisocyanate and hexamethylene diisocyanate at a molar ratio of 1:3; the mass ratio of the catalyst, the release agent, the polyisocyanate compound, and the polythiol compound is 0.15:1.2:1000; (2) adding polythiol compound and mercapto silane coupling agent modified large particle size titanium dioxide nanoparticles into the mixture, mixing uniformly, then adding mercapto silane coupling agent modified small particle size titanium dioxide nanoparticles, mixing uniformly again, degassing, to obtain a monomer mixture; the average particle size D50 of the large particle size titanium dioxide is 110 nm, the average particle size D50 of the small particle size titanium dioxide is 40 nm; the mass ratio of the large particle size titanium dioxide and the small particle size titanium dioxide is 8%; the mercapto silane coupling agent is mercaptopropyl trimethoxysilane; the mass ratio of the large particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.18; the mass ratio of the small particle size titanium dioxide nanoparticles and the mercapto silane coupling agent is 1:0.18; the polythiol compound is 2,3-dithio (2-mercapto)-1-propane thiol; the molar ratio of -SH in the polythiol compound and -NCO in the polyisocyanate compound is 1:1.13; the mass ratio of the sum of the mass of the small particle size titanium dioxide and the large particle size titanium dioxide to the sum of the mass of the polyisocyanate compound and the polythiol compound is 0.74%; (3) injecting the monomer mixture into a mold, heating from 30℃ to 120℃ for 20h to cure, to obtain an environmentally friendly thiol optical resin material. The refractive index and toughness of the resin are tested by using an Abbe refractometer and an XJJD-50J impact testing machine respectively, the refractive index thereof is 1.652, and the impact strength is 23.28kJ / m 2 .

[0043] As can be seen from the above examples and comparative examples, in the mercaptan optical resin system, a small amount of large-particle-size titanium dioxide is added on the basis of small-particle-size titanium dioxide. The large-particle-size titanium dioxide is not prone to agglomeration and has good dispersibility, and during the blending process, the particulate large-particle-size titanium dioxide is more easily dispersed and can act as a "barrier pile" for the small-particle-size titanium dioxide to prevent agglomeration of the small-particle-size titanium dioxide. At the same time, a small amount of mercapto silane coupling agent is used to modify the surface of the titanium dioxide nanoparticles, which can improve the combination of the titanium dioxide inorganic nanoparticles with the matrix to prepare an organic-inorganic nanocomposite material with more excellent performance. The presence of the nanometer titanium dioxide provides a stress concentration area for the material. Since the strong interfacial bonding between the nanometer titanium dioxide and the mercaptan optical matrix is conducive to the transmission of stress, and will not cause structural fracture due to excessive local stress, this strengthens the strength and toughness of the material, thereby achieving the enhancement of the mechanical properties of the composite material. The addition of the small-particle-size titanium dioxide and the large-particle-size titanium dioxide further improves the mechanical strength of the mercaptan optical resin on the basis of maintaining the high refractive index of the mercaptan optical resin. Compared with Example 11, Comparative Example 1-2 lacks small-particle-size titanium dioxide and large-particle-size titanium dioxide, respectively, and cannot exert the quantum size effect of inorganic nanoparticles, and cannot effectively improve the mechanical properties of the mercaptan optical resin. Compared with Example 11, Comparative Example 3 adds an excessive amount of large-particle-size titanium dioxide. The addition of a large amount of large-particle-size inorganic nanoparticles not only easily leads to uneven mixing of the system, but also reduces the uniformity of the particle size and the isolation effect of the large-particle-size titanium dioxide. Although the optical performance is not greatly affected, the impact toughness is greatly reduced, and it is difficult to meet the use requirements.

[0044] The embodiments are only illustrative of the patent and do not limit the protection scope of the patent. The person skilled in the art can also make partial changes, as long as the spirit and essence of the patent are not exceeded, and all are considered as equivalent replacements of the patent and are within the protection scope of the patent.

Claims

1. A method for preparing an environmentally friendly thiol optical resin material, characterized by, The method comprises the following steps: (1) mixing the catalyst, the release agent and the polyisocyanate compound in advance to prepare a mixture; (2) adding the polythiol compound and the mercapto silane coupling agent modified titanium dioxide nanoparticles into the mixture, mixing uniformly, degassing to obtain a monomer mixture; the titanium dioxide nanoparticles are composed of small-particle-size titanium dioxide with an average particle size of less than or equal to 50 nm and large-particle-size titanium dioxide with an average particle size of less than or equal to 150 nm; wherein the average particle size of the large-particle-size titanium dioxide is at least 50 nm larger than that of the small-particle-size titanium dioxide, and the mass ratio of the large-particle-size titanium dioxide to the small-particle-size titanium dioxide is 0.4%-4%; (3) injecting the monomer mixture into a mold, warming and curing to obtain the environmentally friendly thiol optical resin material.

2. The method for preparing an environmentally friendly thiol optical resin material as described in claim 1, characterized in that, The catalyst in step (1) comprises one or more of amine compounds or organotin compounds.

3. The method for preparing an environmentally friendly thiol optical resin material as described in claim 1, characterized in that, The release agent in step (1) is a phosphate compound.

4. The method for preparing an environmentally friendly thiol optical resin material as described in claim 1, characterized in that, The mercapto silane coupling agent in step (2) is one or more of mercaptopropyl trimethoxysilane, mercaptopropyl triethoxysilane, mercaptopropyl methyldimethoxysilane, mercaptopropyl methyldiethoxysilane and mercaptomethyl methyldiethoxysilane.

5. The method for preparing an environmentally friendly thiol optical resin material as described in claim 1, characterized in that, The polythiol compound in step (2) is one or more of methanedithiol, ethanedithiol, propanedithiol, hexanedithiol, cyclohexanedithiol, propanetriol, pentaerythritol tetra(3-mercaptopropionate), trimethylolpropane tri(3-mercaptopropionate), pentaerythritol tetra(3-mercaptobutyrate) and 2,3-dithio(2-mercapto)-1-propane thiol.

6. The method for preparing an environmentally friendly thiol optical resin material as described in claim 1, characterized in that, The average particle size of the small-particle-size titanium dioxide in step (2) is 25-50 nm.

7. The method for preparing an environmentally friendly thiol optical resin material as described in claim 1, characterized in that, The molar ratio of -SH in the polythiol compound to -NCO in the polyisocyanate compound in step (2) is 1:1.1-1.

15.

8. The method for preparing an environmentally friendly thiol optical resin material as described in claim 1, characterized in that, The polythiol compound in step (2) is 2,3-dithio(2-mercapto)-1-propane thiol, which is prepared by adding mercaptoethanol into a reactor, then adding sodium hydroxide solution dropwise, stirring uniformly, then adding epichlorohydrin dropwise, reacting for 0.5-1 h, then adding concentrated hydrochloric acid and a thiourea salt solution, then performing alkaline hydrolysis with ammonia water, washing with water, and removing water and separating to obtain 2,3-dithio(2-mercapto)-1-propane thiol.

9. The method for preparing an environmentally friendly thiol optical resin material as described in claim 1, characterized in that, The warming process in step (3) is heating from 30℃ to 120℃ for 18-22 h.

10. An environmentally friendly mercaptan optical resin material, characterized by comprising: The environmentally friendly thiol optical resin material is prepared by the method of any one of claims 1-9.