A method for preparing a high refractive index (double bond-containing) UV-curable acrylate film

Abstract

The application provides a preparation method of a high-refractive (double bond) UV-cured acrylate film, and belongs to the technical field of preparation of light-cured films. The system used in the application is composed of four parts: A. acrylate monomer containing a flexible long chain; B. acrylate monomer containing an aromatic ring; C. double bond-containing thiophene or selenophene functional monomer; and D. photo-crosslinking initiator. Since the polymer system contains sulfur or selenium atoms with high molar refractivity, and also contains a thiophene group or an aromatic ring with high molar refractivity and low molar volume, the two synergistically improve the refractive index of the polymer. The film prepared by the method has relatively high refractivity, and the refractive index is greater than 1.65. The high-refractive UV-cured acrylate film prepared by the application can be used in the industrial fields of optical materials, electronic packaging and flexible electronics.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of light-cured film preparation, and provides a preparation method of a high-refractive UV-cured acrylate film containing a mercapto group. BACKGROUND

[0002] High-refractive polymers often introduce sulfur atoms with high molar refractivity to increase the refractive index of the polymers. Selenium atoms and sulfur atoms are in the same main group element. Compared with sulfur, selenium has a larger atomic radius, lower electronegativity, weaker bond energy, and higher molar refractivity. The selenium-containing polymers obtained by introducing selenium into polymers exhibit sensitive response to various external stimuli, and are therefore widely used in the fields of intelligent nanocarriers, artificial enzymes, shape memory materials, self-healing materials, etc. Selenium thiophene, as a common selenium-containing heterocyclic compound, has good application prospects in the fields of optoelectronic material application, natural product and drug synthesis, and protein molecule construction, due to its photoelectric performance and biological activity.

[0003] Chinese patent CN114853979A discloses a high-refractive UV resin with high cost performance and a preparation method thereof. A product 1 is synthesized by using (methyl) acrylic acid hydroxy ester, a benzene ring-containing anhydride, and bisphenol A type epoxy resin; a product 2 is synthesized by using diisocyanate and (methyl) acrylic acid hydroxy ester; the product 1 (hydroxyl group) and the product 2 (isocyanate group) are reacted in a certain ratio, and then the reaction endpoint is determined by titration and Fourier infrared spectroscopy. Although the application obtains a resin with high refractive index by introducing a benzene ring-containing structure and increasing the functionality of the UV resin, and has low raw material cost, high cost performance, simple synthesis process, and strong market competitiveness, the system only relies on the benzene ring structure to increase the refractive index of the polymer. If used in the fields of optics and electronic materials, color yellowing may occur during use, thereby affecting the performance and interfering with the normal use of optical and electronic components.

[0004] Chinese patent CN109593154B discloses a selenium-containing maleimide polymer, a preparation method and application thereof. The application polymerizes a new structure of selenium-containing maleimide monomer with styrene monomer, and copolymerizes a new type of selenium-containing vinyl monomer with the selenium-containing maleimide. Although the application solves the defects of poor thermal stability and uncontrollable molecular weight, and controllably adjusts the refractive index, so that the application in the field of optics is expanded to a certain extent; however, if the UV curing main monomer in the system is replaced by an acrylate monomer, the production process can be greatly simplified, the cost can be reduced, and the industrial large-scale production can be more beneficial.

[0005] Chinese patent CN115058215A discloses a high-refractive photovoltaic module encapsulant film and its preparation method and use. The polymer is prepared from a high-refractive polyolefin elastomer resin (random or block polymer of ethylene, alpha-olefin, amine-based functionalized comonomer), thermal initiator, co-crosslinking agent, coupling agent, antioxidant, and ultraviolet absorber. Although the polymer of the invention has a unique amino structure, it improves the molar refractivity to some extent, so that the high-refractive photovoltaic module encapsulant film prepared therefrom has a refractive index close to that of tempered glass, can effectively reduce the light loss rate, and slightly improves the light source utilization rate of the photovoltaic module; however, compared with amino groups, the synergistic effect of selenium atoms, sulfur atoms, and thiophene groups, and the proportional adjustment can more accurately obtain the target required refractive index, so that the optical device meets higher actual application requirements.

[0006] The current chemical structure design principle for improving the refractive index of polymers is that the molecular refractive index is inversely proportional to the molar volume and proportional to the molar refractivity; thus, it can be concluded that introducing structures with high molar refractivity and low molar volume can effectively improve the refractive index of materials. In many studies, the refractive index of polymers is improved by introducing sulfur elements; however, selenium atoms and sulfur atoms are elements in the same main group, and selenium has a higher molar refractivity than sulfur; therefore, the invention introduces sulfur and selenium atoms with high molar refractivity, and also introduces thiophene groups and aromatic rings with high molar refractivity and low molar volume, which together play a synergistic role, improving the refractive index of polymers while also having high optical transmittance, low dispersion, excellent mechanical properties, and stability.

[0007] The invention provides a preparation method of a high-refractive (containing mercapto group) UV-cured acrylate film. The invention obtains a high-refractive UV-cured acrylate film by preparing a mixed solution system of acrylate and then curing it by ultraviolet light. The polymer system of the invention introduces sulfur and selenium atoms with high molar refractivity, and also introduces thiophene groups and aromatic rings with high molar refractivity and low molar volume, which together play a synergistic role, improving the refractive index of polymers while also making the polymers have high optical transmittance, low dispersion, excellent mechanical properties, and stability; introducing flexible long-chain acrylate monomers to adjust the viscosity and mechanical properties of the polymers facilitates molding processing. The high-refractive acrylate UV film provided by the invention achieves a balance between high refractive index and good processability and thermal stability; in addition, the synthesis route of the acrylate UV-cured film provided by the invention is simple and efficient, which is conducive to widening its application in the fields of optical materials, electronic packaging, and flexible electronics. SUMMARY

[0008] The present application aims to overcome the shortcomings of the existing high refractive index materials in practical applications, and provides a preparation method of a high refractive index (containing mercapto group) UV-cured acrylate film, which is simple in operation, mild in conditions, easy to control, and high in utilization rate of selenium atoms and sulfur atoms; by introducing sulfur and selenium atoms with high molar refractivity, thienyl and aromatic rings with high molar refractivity and low molar volume are also introduced, which play a synergistic effect together, improve the refractive index of the polymer, and also make the polymer have high optical transmittance, low dispersion, excellent mechanical properties and stability; the introduction of flexible long-chain acrylate monomers can adjust the viscosity and mechanical properties of the polymer, and facilitate the molding process.

[0009] In a first aspect, the present application provides a preparation method of a high refractive index (containing double bond) UV-cured acrylate film, which comprises a flexible long-chain acrylate monomer, an aromatic ring-containing acrylate monomer, a double bond / thienyl-containing functional monomer, and a photo-crosslinking initiator.

[0010] wherein R is (-CH2-)n (n=0, 1, 2, 3, 4, 5);

[0011] Further, the aromatic ring-containing acrylate monomer can be represented by the following structure:

[0012] wherein R is (-CH2-)n (n=0, 1, 2, 3, 4, 5);

[0013] Further, the double bond-containing thienyl or selenothienyl functional monomer includes any one of 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyldithioselenothiophene (A), 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyldiselenothiophene (B), and 2,5-bis[(acryloyloxy)ethylthio]selenothiophene (C), which are represented by the following structures:

[0014]

[0015] Further, the photo-crosslinking initiator includes one or more of benzophenone, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxy-cyclohexylpropanone, hydroxybenzophenone, benzoyldiphenylphosphine, benzophenone, and 2,2'-azobis(2-methylpropanenitrile).

[0016] Preferably, the photo-crosslinking initiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone.

[0017] Further, a preparation of high refractive index (double bond containing) UV curable acrylate film, the specific steps are as follows

[0018] (1) Preparation of double bond containing thiophene or selenothiophene functional monomer, the specific steps are as follows:

[0019] ① Synthesis steps of 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyldithioselenothiophene: a. 2,5-dichloro-3,4-ethyldithiophene, potassium tert-butoxide, 2-mercaptoethanol and N,N dimethylformamide were mixed, stirred at 120°C overnight, and then the solvent was removed under reduced pressure. The crude product was purified by silica gel column chromatography eluted with n-hexane (R f = 0.3) to obtain solid product 2,5-bis[(2-hydroxy)ethylthio]-3,4-ethyldithioselenothiophene. b. The tetrahydrofuran solution of 2,5-bis[(2-hydroxy)ethylthio]-3,4-ethyldithioselenothiophene and dimethyl aniline was cooled in an ice bath. After cooling to 0°C, acryloyl chloride tetrahydrofuran solution was slowly added dropwise. After stirring at room temperature overnight, the solvent was removed under reduced pressure, and the crude product was washed with sodium bicarbonate (aq) and brine. After drying with magnesium sulfate, chromatography on silica gel (5:2 = hexane: ethyl acetate, R f = 0.3) to obtain 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyldithioselenothiophene liquid;

[0020] ② Synthesis steps of 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyldiselenothiophene: a. 2,5-dichloro-3,4-ethyldiselenothiophene, potassium tert-butoxide, 2-mercaptoethanol and N,N dimethylformamide were mixed, stirred at 120°C overnight, and then the solvent was removed under reduced pressure. The crude product was purified by silica gel column chromatography eluted with n-hexane (R f = 0.3) to obtain solid product 2,5-bis[(2-hydroxy)ethylthio]-3,4-ethyldiselenothiophene. b. The tetrahydrofuran solution of 2,5-bis[(2-hydroxy)ethylthio]-3,4-ethyldiselenothiophene and dimethyl aniline was cooled in an ice bath. After cooling to 0°C, acryloyl chloride tetrahydrofuran solution was slowly added dropwise. After stirring at room temperature overnight, the solvent was removed under reduced pressure, and the crude product was washed with sodium bicarbonate (aq) and brine. After drying with magnesium sulfate, chromatography on silica gel (5:2 = hexane: ethyl acetate, R f = 0.3) to obtain 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyldiselenothiophene liquid;

[0021] ③ Synthesis steps of 2,5-bis[(acryloyloxy)ethylthio]selenothiophene: a. Mix 2,5-dibromoselenothiophene, potassium tert-butoxide, 2-mercaptoethanol, and N,N-dimethylformamide, stir overnight at 120°C, and remove the solvent under reduced pressure. The crude product is then subjected to n-hexane (R... f = 0.3) eluted silica gel column chromatography purification yielded the solid product 2,5-bis[(2-hydroxy)ethylthio]selenothiophene. b. A tetrahydrofuran solution of 2,5-bis[(2-hydroxy)ethylthio]selenothiophene and dimethylaniline was cooled in an ice bath. After cooling to 0°C, a tetrahydrofuran solution of acryloyl chloride was slowly added dropwise. After stirring overnight at room temperature, the solvent was removed under reduced pressure, and the crude product was washed with sodium bicarbonate (aq) and brine. After drying with magnesium sulfate, the product was purified by silica gel (5:2 = hexane: ethyl acetate, R f =0.3) Upper chromatography yielded 2,5-bis[(acryloyloxy)ethylthio]selenothiophene liquid;

[0022] (2) Preparation of acrylate mixed solution

[0023] Under N2 atmosphere, room temperature and light-protected conditions, acrylate monomers containing flexible long chains, acrylate monomers containing aromatic rings, thiophene or selenothiophene functional monomers containing double bonds and photocrosslinking initiators were added to a stainless steel container at a monomer molar ratio of 0-8:0-6:2-5:0.1-0.5 and stirred at 300-380 rpm for 60 min, and then allowed to stand for 40 min to obtain an acrylate mixed solution.

[0024] (3) Preparation of high refractive index (including double bond) UV-cured acrylate film

[0025] ① Spin-coat the acrylate mixed solution prepared in step (2) onto a silicone plate;

[0026] ② Place the silicone plate from (3) ① under ultraviolet light with a wavelength of 190-400nm for 50-1200s to cure and form a UV film of 0.01-4mm, thus obtaining a high refractive index (containing double bonds) UV-cured acrylate film.

[0027] Furthermore, a UV-curable acrylate film with a high refractive index (including double bonds) was prepared, with a refractive index greater than 1.6 and a transmittance of over 87% for wavelengths of 450-830 nm.

[0028] Beneficial effects:

[0029] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0030] The invention point of the present invention is that by introducing selenium or sulfur atom with higher molar refraction and aromatic ring with high molar refraction and low molar volume, the mechanical and thermal properties of the polymer can be improved, and the refractive index of the polymer can be increased to above 1.6. The introduction of flexible long-chain acrylate monomers can adjust the viscosity and mechanical properties of the polymer, facilitate the molding process, and further broaden the application field. DETAILED DESCRIPTION

[0031] Example 1

[0032] (1) Preparation of thienyl or selenothienyl functional monomer containing double bond, the specific steps are as follows:

[0033] a. Mix 2,5-dichloro-3,4-ethyldithiotiophene (14.7 mmol), potassium tert-butoxide (29.4 mmol), 2-dimercaptoethanol (29.4 mmol) and N,N-dimethylformamide (40 ml), stir overnight at 120°C, then remove the solvent under reduced pressure. The crude product is purified by silica gel column chromatography eluted with n-hexane (R f = 0.3) to obtain solid product 2,5-bis[(2-hydroxy)ethylthio]-3,4-ethyldithioselenothiophene (21.7 mmol, 67.7%).

[0034] b. Cool the solution of 2,5-bis[(2-hydroxy)ethylthio]-3,4-ethyldithioselenothiophene (4.26 mmol) and dimethyl aniline (17.04 mmol) in tetrahydrofuran (18 mL) in an ice bath. After cooling to 0°C, slowly drop acryloyl chloride (12.78 mmol) in tetrahydrofuran (10 ml). Stir overnight at room temperature, then remove the solvent under reduced pressure. Wash the crude product with sodium bicarbonate (aq) and brine. Dry with magnesium sulfate, then chromatograph on silica gel (5:2 = hexane: ethyl acetate, R f = 0.3) to obtain 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyldithioselenothiophene liquid.

[0035] (2) Preparation of acrylate mixed solution

[0036] Under N2 atmosphere, room temperature and light shielding conditions, acrylate propyl ester, phenylethyl acrylate, 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyldithioselenothiophene and photocrosslinking initiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone are added to a stainless steel container in a monomer molar ratio of 4:2:1:0.3, stirred and mixed at a speed of 320 rpm, stirred for 60 min, and static for 40 min to obtain an acrylate mixed solution.

[0037] (3) Preparation of high refractive index (including double bond) UV-cured acrylate film

[0038] ① Spin-coat the acrylate mixed solution prepared in step (2) onto a silicone plate;

[0039] ② Place the silicone plate from ① under ultraviolet light with a wavelength of 395nm for 200s to cure and form a 0.12mm UV film, thus obtaining a high refractive index (containing double bonds) UV-cured acrylate film.

[0040] Determination of the refractive index of high refractive index (including double bonds) UV-cured acrylate films:

[0041] At room temperature, the refractive index was measured to be 1.674 using an Abbe refractometer.

[0042] Implementation Case 2

[0043] (1) Preparation of thiophene or selenthiophene functional monomers containing double bonds, the specific steps are as follows:

[0044] a. 2,5-Dichloro-3,4-ethyldiselenothiophene (14.7 mmol), potassium tert-butoxide (29.4 mmol), 2-mercaptoethanol (29.4 mmol), and N,N-dimethylformamide (40 ml) were mixed and stirred overnight at 120 °C, followed by solvent removal under reduced pressure. The crude product was then subjected to n-hexane (R... f Purified by silica gel column chromatography eluted with 0.3 g / mL, yielding the solid product 2,5-bis[(2-hydroxy)ethylthio]-3,4-ethyldiselenothiophene (21.7 mmol, 67.7%).

[0045] b. A solution of 2,5-bis[(2-hydroxy)ethylthio]-3,4-ethyldiselenothiophene (4.26 mmol) and dimethylaniline (17.04 mmol) in tetrahydrofuran (18 ml) was cooled in an ice bath. After cooling to 0°C, a solution of acryloyl chloride (12.78 mmol) in tetrahydrofuran (10 ml) was slowly added dropwise. After stirring overnight at room temperature, the solvent was removed under reduced pressure, and the crude product was washed with sodium bicarbonate (aq) and brine. After drying with magnesium sulfate, the product was dried on silica gel (5:2 = hexane: ethyl acetate, R...). f = 0.3) Upper chromatography yielded 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyldiselenothiophene liquid.

[0046] (2) Preparation of acrylate mixed solution

[0047] The acrylic ester butyl ester, acrylic phenyl propyl ester, 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyl diselenothiophene and photocrosslinking initiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone were mixed in a stainless steel container under stirring at room temperature and in the dark at a monomer molar ratio of 4:2:1:0.3, the stirring speed was 320 rpm, the stirring time was 60 min, and the standing time was 40 min, to obtain an acrylic ester mixed solution.

[0048] (3) Preparation of high-refractive (containing double bond) UV-cured acrylic ester film

[0049] ① The acrylic ester mixed solution prepared in step (2) was spin-coated on a silica gel plate;

[0050] ② The silica gel plate in ① of (3) was irradiated under 395 nm ultraviolet light for 200 s to form a 0.12 mm UV film, thereby obtaining a high-refractive (containing double bond) UV-cured acrylic ester film.

[0051] Determination of the refractive index of the high-refractive (containing double bond) UV-cured acrylic ester film:

[0052] The refractive index was 1.714, which was measured by an Abbe refractometer at room temperature.

[0053] Example 3

[0054] (1) Preparation of a double bond-containing thiophene or selenothiophene functional monomer, the specific steps are as follows:

[0055] a. 2,5-dibromoselenothiophene (14.7 mmol), potassium tert-butoxide (29.4 mmol), 2-mercaptoethanol (29.4 mmol) and N,N-dimethylformamide (40 ml) were mixed and stirred at 120°C overnight, and then the solvent was removed under reduced pressure. The crude product was purified by column chromatography on silica gel eluted with n-hexane (R f = 0.3) to obtain solid 2,5-bis[(2-hydroxy)ethylthio]selenothiophene (21.7 mmol, 67.7%).

[0056] b. A solution of 2,5-bis[(2-hydroxy)ethylthio]selenothiophene (4.26 mmol) and dimethylphenylamine (17.04 mmol) in tetrahydrofuran (18 ml) was cooled in an ice bath. After cooling to 0°C, acryloyl chloride (12.78 mmol) in tetrahydrofuran (10 ml) was slowly added dropwise. After stirring at room temperature overnight, the solvent was removed under reduced pressure, and the crude product was washed with sodium bicarbonate (aq) and brine. After drying with magnesium sulfate, it was chromatographed on silica gel (5:2 = hexane: ethyl acetate, R f = 0.3) to obtain 2,5-bis[(acryloyloxy)ethylthio]selenothiophene liquid.

[0057] (2) Preparation of the acrylate mixed solution

[0058] Under the conditions of N2 atmosphere, room temperature, and light shielding, acrylate pentyl ester, phenylbutyl acrylate, 2,5-bis[(acryloyloxy)ethylthio]selenophene, and photocrosslinking initiator 2-hydroxy-4'- (2-hydroxyethoxy) -2-methylpropiophenone were added into a stainless steel container for stirring and mixing at a monomer molar ratio of 4:2:1:0.3, a stirring speed of 320 rpm, a stirring time of 60 min, and a static time of 40 min, to obtain the acrylate mixed solution.

[0059] (3) Preparation of the high-refractive (containing double bond) UV-cured acrylate film

[0060] ① The acrylate mixed solution prepared in step (2) was spin-coated on a silica gel plate;

[0061] ② The silica gel plate of ① in (3) was irradiated under 395 nm ultraviolet light for 200 s to form a 0.12 mm UV film, i.e., the high-refractive (containing double bond) UV-cured acrylate film.

[0062] Determination of the refractive index of the high-refractive (containing double bond) UV-cured acrylate film:

[0063] The refractive index was 1.653, which was measured by an Abbe refractometer at room temperature.

[0064] In summary, the preparation method of the high-refractive (containing thiol group) UV-cured acrylate film has the advantages of simple operation, mild and easy-to-control conditions, high utilization rate of selenium atoms and sulfur atoms, introduction of low-molar-volume thiophene groups and aromatic rings to improve the mechanical properties and thermal properties of the polymer, and further improve the refractive index of the polymer. The uniform and dense acrylate cured film is quickly formed by using the ultraviolet curing technology, realizing high refractive index, good stability, easy processing, and other excellent comprehensive properties, which is conducive to widening the application in the fields of optical materials, electronic packaging, and flexible electronics.

Claims

1. A UV-cured acrylate film with high refractive index, characterized in that, High transparency to visible light of 450-830nm wavelength after photocuring film formation; the acrylate UV cured film is composed of flexible long chain containing acrylate monomer, aromatic ring containing acrylate monomer, double bond containing thiophene or selenothiophene functional monomer and photocrosslinking initiator; The flexible long chain containing acrylate monomer is represented by the following structure: In which, R group is (-CH2-)n, n=3, 4, 5; The aromatic ring containing acrylate monomer is represented by the following structure: In which, R group is (-CH2-)n, n=0, 1, 2, 3, 4, 5; The double bond containing thiophene or selenothiophene functional monomer includes any one of 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyldithioselenothiophene (A), 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyldiselenothiophene (B), 2,5-bis[(acryloyloxy)ethylthio]selenothiophene (C), the structures of which are represented in turn as follows: ； The high refractive index UV cured acrylate film is prepared by the following method, the specific steps are as follows: (1) Preparation of double bond containing thiophene or selenothiophene functional monomer, the specific steps are as follows: 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyldithioselenothiophene synthesis steps: a. 14.7 mmol of 2,5-dichloro-3,4-ethyldithiophene, 29.4 mmol of potassium tert-butoxide, 29.4 mmol of 2-dimercaptoethanol and 40 ml of N,N dimethylformamide were mixed and after stirring overnight at 120°C the solvent was removed under reduced pressure; the crude product was purified by column chromatography on silica gel eluted with n-hexane R f = 0.3 to give 21.7 mmol, 67.7% of the solid product 2,5-bis[(2-hydroxy)ethylthio]-3,4- ethyldithioselenophene; b. A solution of 4.26 mmol of 2,5-bis[(2-hydroxy)ethylthio]-3,4- ethyldithioselenothiophene and 17.04 mmol of dimethyl aniline in 18 mL of tetrahydrofuran was cooled in an ice bath; after cooling to 0°C, 12.78 mmol of acryloyl chloride in 10 mL of tetrahydrofuran was added dropwise; after stirring at room temperature overnight, the solvent was removed under reduced pressure and the crude product was washed with sodium bicarbonate and brine; after drying over magnesium sulfate, it was chromatographed on silica gel with hexane:ethyl acetate = 5:2, Rf = 0.3, to give 2,5-bis[(2-acryloyloxy)ethylthio]-3,4- ethyldithioselenothiophene as a liquid. f = 0.3, to give 2,5-bis[(2-acryloyloxy)ethylthio]-3,4- ethyldithioselenothiophene as a liquid. 2,5-bis[(2-acryloyloxy)ethylthio]-3,4-ethyldiselenothiophene synthesis steps: a. 14.7 mmol of 2,5-dichloro-3,4-ethyldiselenolothiophene, 29.4 mmol of potassium tert-butoxide, 29.4 mmol of 2-mercaptoethanol and 40 ml of N,N dimethylformamide were mixed and, after stirring overnight at 120°C, the solvent was removed under reduced pressure; the crude product was purified by column chromatography on silica gel eluted with n-hexane R f = 0.3 to give 21.7 mmol, 67.7% of the solid product 2,5-bis[(2-hydroxy)ethylsulfanyl]-3,4-ethyldiselenolothiophene; b. A solution of 4.26 mmol of 2,5-bis[(2-hydroxy)ethylthio]-3,4- ethyldiselenothiophene and 17.04 mmol of dimethyl aniline in 18 ml of tetrahydrofuran is cooled in an ice bath; after cooling to 0°C, 12.78 mmol of acryloyl chloride in 10 ml of tetrahydrofuran is injected; after stirring overnight at room temperature, the solvent is removed under reduced pressure and the crude product is washed with sodium bicarbonate and brine; after drying over magnesium sulfate, it is chromatographed on silica gel with hexane: ethyl acetate = 5:2, Rf = 0.3 to give 2,5-bis[(2-acryloyloxy)ethylthio]-3,4- ethyldiselenothiophene as a liquid. f ​ 2,5-bis[(acryloyloxy)ethylthio]selenothiophene synthesis steps: a. 14.7 mmol of 2,5-dibromoselenophene, 29.4 mmol of potassium tert-butoxide, 29.4 mmol of 2-mercaptoethanol and 40 ml of N,N dimethylformamide were mixed and stirred at 120°C overnight, after which the solvent was removed under reduced pressure; the crude product was purified by column chromatography on silica gel eluted with n-hexane R f = 0.3 to give 21.7 mmol, 67.7% of the solid product 2,5-bis[(2-hydroxy)ethylsulfanyl]selenophene; b. A solution of 4.26 mmol of 2,5-bis[(2-hydroxy)ethylthio]selenothiophene and 17.04 mmol of dimethyl aniline in 18 ml of tetrahydrofuran was cooled in an ice bath; after cooling to 0°C, 12.78 mmol of acryloyl chloride in 10 ml of tetrahydrofuran was injected; after stirring overnight at room temperature, the solvent was removed under reduced pressure and the crude product was washed with sodium bicarbonate and brine; after drying over magnesium sulfate, it was chromatographed on silica gel with hexane:ethyl acetate = 5:2, Rf = 0.3 to give 2,5-bis[(acryloyloxy)ethylthio]selenothiophene liquid; f = 0.3 to give 2,5-bis[(acryloyloxy)ethylthio]selenothiophene liquid; (2) Preparation of acrylate mixed solution, the specific steps are as follows: Under the conditions of N2 atmosphere, room temperature and light shielding, the flexible long chain containing acrylate monomer, the aromatic ring containing acrylate monomer, the double bond containing thiophene or selenothiophene functional monomer and the photocrosslinking initiator are added to a stainless steel container for stirring and mixing at a speed of 300-380 rpm for 60 min and static for 40 min to obtain an acrylate mixed solution; (3) Preparation of high refractive index UV cured acrylate film, the specific steps are as follows: ① The acrylate mixed solution prepared in step (2) is spin-coated on a silica gel plate; ② The silica gel plate in step ① is irradiated under ultraviolet light of 190-400 nm wavelength for 50-1200 s to form a 0.01-4 mm UV film, i.e. a high refractive index UV cured acrylate film.

2. The UV-cured acrylate film with high refractive index according to claim 1, characterized in that, The photocrosslinking initiator includes one or more of benzoketone, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxy-cyclohexylpropanone, hydroxybenzophenone, benzoyldiphenylphosphine, benzophenone, 2,2'-azobis(2-methylpropionitrile).

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