Preparation method and application of photocuring sulfydryl silicon resin and organic silicon pressure-sensitive adhesive

Abstract

The invention belongs to the technical field of organic silicon resin, and particularly relates to a preparation method and application of light-cured sulfydryl silicon resin and an organic silicon pressure-sensitive adhesive. A functional sulfydryl group is grafted on a chain link D or a chain link T in the light-cured sulfydryl silicon resin, and through the coordination of the photosensitive activity design of the sulfydryl group and the optimal design of a molecular chain link unit, the matrix resin is endowed with an efficient light-curing characteristic, so that the bonding strength, the thermal stability and the aging resistance can be greatly improved, and the service life of the light-cured sulfydryl silicon resin is prolonged. The preparation method has the advantages that the process is simple and convenient, the reaction condition is mild, the storage period is long, the production efficiency is high, the product is stable, the raw material source is wide, the cost is low, the industrial production can be realized, and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of silicone resins, and particularly relates to a method for preparing and applying a photocurable mercapto silicone resin and a silicone pressure-sensitive adhesive. Background Art

[0002] Silicone pressure-sensitive adhesives (SiPSAs) have become indispensable key materials in the high-end manufacturing field due to their excellent weather resistance, high and low temperature resistance, electrical insulation, and biocompatibility. In recent years, with the rapid development of photocuring technology, ultraviolet (UV)-curable silicone pressure-sensitive adhesives have gradually become a research hotspot due to their advantages such as high efficiency, energy saving, and environmental friendliness. However, there are still many limitations in the existing technologies, making it difficult to meet the increasing high-performance requirements. The existing SiPSA products are mainly adjustable solvent-based addition SiPSAs, and the manufacturers mainly include Dow and Momentive in the United States, Wacker in Germany, and Shin-Etsu in Japan. Solvent-based SiPSAs need to use toluene, xylene, ethyl acetate, methyl ethyl ketone, or a mixture of two of them as the dispersion medium, and the VOC content is generally higher than 20%, resulting in certain environmental pollution. In addition, the peel strength is less than 1200 g / (25 mm), and the upper temperature limit of heat resistance is only 250 °C, which cannot meet the long-term high-temperature (>300 °C) use requirements of 5G devices. Takahide et al. used vinyl polysiloxane, MQ silicone resin, hydrogen-containing silicone oil, and a small amount of organic solvents as raw materials and a platinum complex as a catalyst to prepare a SiPSA with a solid mass fraction of 75%, which has excellent high-temperature resistance, but still has the environmental pollution problem caused by the presence of organic solvents.

[0003] Currently, the domestic research and development of SiPSA generally focuses on the development towards environmental friendliness and low VOC. While SiPSA is developing towards low VOC, it is also developing towards low energy consumption and high performance. Ultraviolet (UV) curing technology refers to a new process that uses UV to induce the rapid cross-linking and forming of liquid photosensitive prepolymers and monomers in a short time. It is a "5E" green and environmentally friendly emerging technology with high efficiency, energy saving, environmental friendliness, wide adaptability, low VOC emissions, and environmental friendliness, and has excellent spatio-temporal controllability and spatial selectivity. Introducing UV curing technology into the preparation of silicone materials for the production of UV-curable SiPSA is expected to replace the traditional semi-automatic thermal curing coating process in industrialization, significantly improve the curing rate and production efficiency, significantly reduce energy consumption and production costs, and further improve the product competitiveness.

[0004] Click chemistry is widely used in the construction of functional polymers due to its wide source of raw materials, rapid and efficient, mild conditions, high reaction rate, simple separation and purification, resistance to chemical solvents and good stereoselectivity. As the most important type of click chemistry, thiol-ene photo-click reaction has the characteristics of click reaction and light-time and space controllability. In addition, because it is insensitive to oxygen and water, it can significantly overcome oxygen inhibition, greatly improve the photocuring rate and monomer conversion rate, and can achieve rapid curing and molding in air atmosphere. It is energy-saving and environmentally friendly. It is currently one of the most effective methods for photosensitization of silicone materials.

[0005] Patent CN 118755446 B discloses a UV-curable silicone pressure-sensitive adhesive material and a preparation method thereof. The invention mixes 107 silicone rubber, vinyl MQ silicone resin, γ-methacryloxypropyl trimethoxysilane, octamercapto cage-type polysilsesquioxane, mercapto-modified titanium dioxide, functionalized ionic liquid, tackifier, catalyst, photoinitiator and solvent, and stirs for 20-30 minutes to obtain a UV-curable silicone pressure-sensitive adhesive material. The obtained silicone pressure-sensitive adhesive has good aging resistance, high peel strength and long-lasting adhesion. The preparation process of this patent requires the use of solvent mixed materials. Although the final performance is excellent, the solvent-based process still has environmental pollution.

[0006] Patent CN 119242257 A discloses a foamed silicone pressure-sensitive adhesive and a preparation method thereof. The invention mixes vinyl rubber, hydroxy nano-reinforcement agent, hydroxy silicone oil, methyl MQ silicone resin, hydroxy MQ silicone resin, inhibitor and organic solvent and heats them to react, obtaining a main agent of silicone pressure-sensitive adhesive, and then adding an appropriate amount of organic solvent, hydrogen-containing silicone oil and catalyst to fully stir, obtaining a silicone pressure-sensitive adhesive coating liquid, and then coating it on a 50μm thick first fluorine release film, placing it in an oven for curing and taking it out, obtaining a dry adhesive with a thickness of 100μm, and attaching a 50μm second fluorine release film on its surface to obtain a foamed silicone pressure-sensitive adhesive. The foamed silicone pressure-sensitive adhesive has the performance of both bonding strength and point impact resistance, but the foaming process is complicated, and a thermal curing method is used, the curing time is long, and the energy consumption is high. Summary of the invention

[0007] In order to solve the problems in the above-mentioned prior art, the present invention provides a photocurable mercapto silicone resin, which is prepared by a hydrolysis-condensation method. The photosensitive activity design of the mercapto group and the optimized design of the molecular chain unit are coordinated to give the base resin efficient photocuring properties, which can greatly improve the bonding strength, thermal stability and aging resistance. The resin is a colorless, transparent and viscous substance at room temperature, has no irritating odor, and has the advantages of high visible light transmittance, rapid curing, room temperature stability and good storage stability.

[0008] The present invention also provides a silicone pressure-sensitive adhesive prepared from the above-mentioned photocurable mercapto-silicone resin. The silicone pressure-sensitive adhesive is rapidly prepared under ultraviolet light based on the thiol-ene photopolymerization mechanism, and has good adhesive properties, tack, holding power, peel strength, and aging and weather resistance, solving the problems of long thermal curing time, low adhesive strength, complex process, high energy consumption, and VOC emissions caused by the use of organic solvents in traditional silicone pressure-sensitive adhesives.

[0009] The present invention also provides the use of the above-mentioned photocurable mercapto-silicone resin, which can be widely applied in the fields of pressure-sensitive adhesives, electronic packaging, optical devices, medical dressings, flexible displays, etc.

[0010] The present invention will achieve the above object through the following technical solutions:

[0011] The present invention provides a photocurable mercapto-silicone resin, which conforms to the following general formula:

[0012] [R 1 R 2 R 3 SiO 1 / 2 a [R 4 R 5 SiO 2 / 2 b [R 6 SiO 3 / 2 c [SiO 4 / 2 d ; (R is an organic group or a hydrogen atom)

[0013] Among them, R 1 , R 2 and / or R 3 is one or more of a hydrogen atom, a monovalent hydrocarbon group without aliphatic unsaturated bonds, or an unsaturated hydrocarbon group containing 2-10 carbon atoms;

[0014] Among them, R 4 is methyl or phenyl, R 5 is methyl, phenyl, -CH 2 SH, -CH 2 CH 2 SH or -CH 2 CH 2 CH 2 SH, and R 6 is -CH 2 SH, -CH 2 CH 2 SH or -CH 2 CH 2 CH 2 SH;

[0015] ​​​​Among them, a, b, c, and d ≥ 0 and at most two of a, b, c, and d are 0.

[0016] The photocurable mercapto silicone resin described in the present invention includes at least two combinations of monofunctional silane linkages (R 3 SiO 1 / 2 , namely M), difunctional silane linkages (R 2 SiO 2 / 2 , namely D), trifunctional silane linkages (RSiO 3 / 2 , namely T), and tetrafunctional silane linkages (SiO 4 / 2 , namely Q), wherein at least one of the D linkages and / or T linkages contains a mercapto group, so that the silicone resin has the ability of ultraviolet light curing.

[0017] Specifically, the D-linkage silicon-oxygen structure monomers are at least one of γ-mercaptopropylmethyldimethoxysilane (KH970), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dimethylcyclosiloxane cyclic oligomers (DMC), dimethyldiethoxysilane (DP-322), dimethyldimethoxysilane (DP-321), diphenyldimethoxysilane (DP-820), and methylphenyldimethoxysilane (DP-830).

[0018] Specifically, the T-linkage silicon-oxygen structure monomers are at least one of γ-mercaptopropyltriethoxysilane (KH580), γ-mercaptopropyltrimethoxysilane (KH590), methyltrimethoxysilane (DP-311), and methyltriethoxysilane (DP-301).

[0019] Specifically, the Q-linkage silicon-oxygen structure monomers are at least one of methyl orthosilicate (Tetramethyl orthosilicate, TMOS), ethyl orthosilicate (Tetraethyl orthosilicate, TEOS), propyl orthosilicate (Tetrapropylorthosilicate, TPOS), and butyl orthosilicate (Tetrabutyl orthosilicate, TBOS).

[0020] The photocurable mercapto silicone resin described in the present invention must contain T linkages and / or Q linkages, including MDQ mercapto silicone resin, MTQ mercapto silicone resin, MDT mercapto silicone resin, or DT mercapto silicone resin.

[0021] Specifically, the MDQ mercapto silicone resin includes the following general formula: [R 1 R 2 R 3 SiO 1 / 2 a [R 4 R 5 ​SiO 2 / 2 b [SiO 4 / 2 d , wherein: R 1 , R 2 and R 3 are methyl, R 4 is methyl, R 5 is -CH 2 SH, -CH 2 CH 2 SH or -CH 2 CH 2 CH 2 SH, and a, b, and d > 0.

[0022] Specifically, the MTQ mercapto silicone resin includes the following general formula: [R 1 R 2 R 3 SiO 1 / 2 a [R 6 SiO 3 / 2 c [SiO 4 / 2 d , wherein: R 1 , R 2 and R 3 are methyl, R 6 is -CH 2 SH, -CH 2 CH 2 SH or -CH 2 CH 2 CH 2 SH, and a, c, and d > 0.

[0023] Specifically, the MDT mercapto silicone resin includes the following general formula: [R 1 R 2 R 3 SiO 1 / 2 a [R 4 R 5 SiO 2 / 2 b [R 6 SiO 3 / 2 c , wherein: R 1 , R 2 , R 3 , R 4 and R 5 are methyl, R 6 is -CH 2 SH, -CH 2 CH​​​​​​​​2 SH or -CH 2 CH 2 CH 2 One of SH, a, b and c > 0.

[0024] Specifically, the DT mercapto silicone resin includes the following general formula: [R 4 R 5 SiO 2 / 2 b [R 6 SiO 3 / 2 c , where: R 4 and R 5 are phenyl groups, R 6 is -CH 2 SH, -CH 2 CH 2 SH or -CH 2 CH 2 CH 2 SH, b and c > 0.

[0025] Further, in the general formula, when a ≠ 0, a / (b + c + d) = 0.6 - 1.2.

[0026] Further, in the general formula, R 1 , R 2 and R 3 are methyl groups.

[0027] Further, in the photocurable mercapto silicone resin, the mercapto content is 0.07 - 0.49 mol / 100 g.

[0028] Further, the photocurable mercapto silicone resin has a dynamic viscosity of 100 - 20000 mPa·s at 25°C, a refractive index of 1.40 - 1.49 at 25°C, and a visible light transmittance ≥ 85%.

[0029] The present invention provides a method for preparing the above photocurable mercapto silicone resin, including the following steps: reacting a silane monomer containing a hydrolyzable group, a capping agent, and deionized water under the promotion of an acid, a base, a salt, or a metal oxide by a hydrolysis polycondensation method to obtain the photocurable mercapto silicone resin.

[0030] Further, the silane monomer containing a hydrolyzable group includes a mercapto silane monomer, especially a mercapto silane monomer with D and / or T linkages.

[0031] Specifically, the silane monomer containing a hydrolyzable group includes a mercapto silane monomer with D and / or T linkages, and at least one of a siloxane structure monomer with D, T, or Q linkages.

[0032] ​​Specifically, the D and / or T chain segment mercapto-silane monomers are at least one of γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptomethylmethyldimethoxysilane, γ-mercaptomethylmethyldiethoxysilane, γ-mercaptomethylmethyldimethoxysilane, γ-mercaptomethylmethyldiethoxysilane.

[0033] Specifically, the addition amount of the capping agent is generally 20-78 parts by mass, including but not limited to capping agents commonly used in silicone polymerization such as alkylsilane capping agents, vinylsilane capping agents, and hydrogen-based silane capping agents. Among them, the alkylsilane capping agents include but not limited to hexamethyldisiloxane, hexaethyldisiloxane, trimethylchlorosilane, methyltrimethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, hexamethyldisilazane, hexaphenyldisiloxane, trimethylsilanol, triethylsilanol, etc.

[0034] Specifically, the molar addition amount of deionized water is 1.6-4 times that of the mercapto-silane monomer. Adding water dropwise can hydrolyze the alkoxysilane into a silanol compound, which helps the subsequent polycondensation reaction.

[0035] Specifically, acids, bases, salts, metal oxides, etc. can be added to promote the hydrolysis reaction. The addition amount is generally 0.2%-2% of the total mass of the silane monomer, including but not limited to concentrated sulfuric acid with a mass fraction of 98%, concentrated hydrochloric acid with a mass fraction of 37%, trifluoromethanesulfonic acid, anhydrous acetic acid, oxalic acid, trichloroacetic acid, trifluoroacetic acid, strongly acidic cation exchange resin, tetramethylammonium hydroxide, etc.

[0036] Specifically, the reaction temperature of the hydrolysis-polycondensation reaction is 50°C-95°C, and the time is 2h-8h.

[0037] Specifically, after the polycondensation reaction, a purification step is further included. The purification step includes neutralization after cooling, primary distillation, water washing and separation, etc., to obtain purified photocurable mercapto silicone resin. Among them, neutralization is to remove the acidic catalyst or basic catalyst in the system. For removing the basic catalyst, anhydrous formic acid or anhydrous acetic acid can be selected. For removing the acidic catalyst, one or several of sodium carbonate, calcium carbonate, magnesium carbonate, ammonium carbonate, sodium bicarbonate, ammonium bicarbonate, magnesium bicarbonate, etc. can be selected, and they are formulated into a saturated solution of 50% ethanol-water and used as the washing liquid for the water washing step to wash 3 times; the primary distillation refers to vacuum distillation at 85-95°C and -0.1 MPa, mainly distilling out the alcohols and water in the system to prevent the organic solvent layer from forming a homogeneous phase with the alcohol and accelerating the reaction in the forward reaction direction to promote the polycondensation process. After water washing and layering, the organic solvent layer is taken for the separation and purification step, including secondary water washing and layering and secondary distillation. Among them, the secondary water washing and layering uses pure deionized water as the washing liquid and a demulsifier is added. The demulsifier is an inert demulsifier, which can be one or several of demulsifier SP-169, BBE20601, AP-05, HA-22, HA-42, DE0712, AE8051, AE9901, and AP113, etc. It can effectively reduce the water washing time, improve the water washing efficiency, accelerate layering, improve the product purity, and improve the post-treatment efficiency. The secondary distillation refers to vacuum distillation at 80°C - 95°C and -0.1 MPa to achieve the purification purpose, and specifically, the solvent can be removed by rotary evaporation. In the above purification step, when it is difficult to achieve the layering effect during the water washing process, resulting in a low yield, it is also possible to choose to cool to room temperature after polycondensation for a certain time, add an appropriate amount of carbonate, stir for 45 minutes to remove acid, then carry out vacuum distillation at 85°C - 95°C and -0.1 MPa to distill out the alcohols and water in the system, and finally carry out filtration.

[0038] The present invention provides the use of the above-mentioned photocurable mercapto silicone resin, which can be applied to fields such as pressure-sensitive adhesives, electronic packaging, optical devices, medical dressings, flexible displays, etc.

[0039] The present invention provides a photocurable organosilicon pressure-sensitive adhesive, which is prepared from the above-mentioned photocurable mercapto silicone resin.

[0040] The present invention provides a preparation method of the above-mentioned photocurable organosilicon pressure-sensitive adhesive, including the following steps: uniformly stirring the photocurable mercapto silicone resin, terminal vinyl silicone oil, anchoring agent and photoinitiator and coating them on a substrate, and carrying out thiol-ene photochemical click crosslinking curing under ultraviolet light irradiation to obtain the photocurable organosilicon pressure-sensitive adhesive.

[0041] Specifically, the addition amount of the photoinitiator is 1%-3% of the sum of the masses of the photocurable mercapto silicone resin, the vinyl-terminated silicone oil, and the anchoring agent. Free radical photoinitiators can be selected, such as benzoin and its derivatives, benzil and its derivatives, α-hydroxyalkyl phenyl ketones, α-aminoalkyl phenyl ketones, acylphosphine oxides, benzophenones, and heterocyclic aromatic ketones, etc., including but not limited to 2-hydroxy-2-methyl-1-phenylpropanone (Darocure 1173), 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO), ethyl 2,4,6-trimethylbenzoyl phenylphosphinate (TPO-L), 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone (Darocure 2959), 1-hydroxy-cyclohexyl-phenyl ketone (Irgacure 184), 2-methyl-1-(4-methylthiophenyl)-2-morpholin-1-propanone (Irgacure 907), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (Irgacure 369), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (Irgacure 819), 1,1-(methylenedi-4,1-phenylene)bis[2-hydroxy-2-methyl-1-propanone] (Irgacure 127), benzophenone (BP), 2,4,6-trimethylbenzophenone, tetraethyl Michler's ketone (DEMK), isopropylthioxanthone (ITX), 1-chloro-4-propoxythioxanthone (CPTX), and photoinitiator EDAB (1101), etc. One or several of them. Among them, 2-hydroxy-methylphenylpropan-1-one (Darocure 1173), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), ethyl 2,4,6-trimethylbenzoyl phenylphosphinate (TPO-L), 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone (Darocure 2959), 1-hydroxy-cyclohexyl-phenyl ketone (Irgacure 184), etc. are preferred.

[0042] Specifically, the addition amount of the anchoring agent is 1%-3% of the sum of the masses of the photocurable mercapto silicone resin and the vinyl-terminated silicone oil. It can be selected as epoxy-modified silicone oil, γ-glycidoxypropyltrimethoxysilane (KH560), γ-methacryloxypropyltrimethoxysilane (KH-570), isopropyltris(dioctylpyrophosphate) titanate (KR-38S), etc.

[0043] Specifically, the ultraviolet light uses a mercury lamp source of 200-450 nm, and the maximum irradiation intensity is 70-150 mW / cm 2 , and the irradiation time is 3 s - 3 min.

[0044] Specifically, the coated substrate is one of polyethylene terephthalate (PET) film, polyimide (PI) film, polytetrafluoroethylene (PTFE) film, biaxially oriented polypropylene (BOPP) film, polyethylene (PE) film, and polyvinyl chloride (PVC) film.

[0045] The present invention provides the use of the above-mentioned photocurable silicone pressure-sensitive adhesive, which can be applied to common fields of pressure-sensitive adhesives.

[0046] The beneficial effects of the present invention are as follows:

[0047] 1. The thiol-ene click reaction has the advantages of high efficiency, high conversion rate, fast reaction speed, high tolerance to various functional groups, no by-products, low shrinkage rate, and extremely low sensitivity to oxygen inhibition under mild reaction conditions, which is beneficial to achieving a highly uniform polymer network and has a unique ability to control the structure. During the thiol-ene click reaction, the thiol group acts as a hydrogen donor, first undergoes hydrogen abstraction with the free radical generated by the photoinitiator to generate a thiyl radical, and then attacks the double bond to initiate a cross-linking reaction. The reason why the oxygen inhibition effect has a relatively low impact on the thiol-ene silicone polymerization system is that although the carbon radical can still react with molecular oxygen, the formed peroxy radical can also extract hydrogen from the thiol, which can re-initiate the thiyl radical to continue chain growth.

[0048] 2. The present invention prepared photocurable thiol silicone resins with different structures by the hydrolysis-polycondensation method, mainly including materials such as MDQ thiol silicone resin, MTQ thiol silicone resin, MDT thiol silicone resin, and DT thiol silicone resin. The structures of the materials were characterized by infrared spectroscopy and nuclear magnetic resonance spectroscopy, proving the successful synthesis of the photocurable precursor materials.

[0049] 3. The synthesized photocurable precursor materials were tested for viscosity, density, refractive index, light transmittance at a wavelength of 450 nm, and storage stability; some thiol silicone resins have relatively high refractive indices and light transmittance at 450 nm.

[0050] 4. The photocuring test of the silicone pressure-sensitive adhesive was carried out, and its TGA, adhesion strength, and 90° peel strength were tested; it was found in the TGA test that the decomposition temperature of the cured silicone pressure-sensitive adhesive material was generally above 400 °C, indicating good heat resistance; after the high-temperature test at 180 °C for 7 days, it still had a relatively high adhesion strength, showing excellent high-temperature resistance and aging resistance; after the photocurable silicone pressure-sensitive adhesive was completely immersed in water at room temperature for 15 days, it still maintained an adhesion strength of more than 50%, indicating excellent weather resistance.

[0051] 5. The photocurable mercapto silicone resin prepared by the present invention includes MDQ mercapto silicone resin, MTQ mercapto silicone resin, MDT mercapto silicone resin and DT mercapto silicone resin. Under the action of a photoinitiator and an anchoring agent, through ultraviolet light irradiation, it crosslinks and cures with vinyl-terminated silicone oil. The mercapto group and the vinyl group combine with each other at specific positions to form a photocurable silicone pressure-sensitive adhesive with a three-dimensional crosslinked network structure. During this reaction process, peroxy free radicals are continuously generated, ensuring the continuous progress of the polymerization reaction, weakening the oxygen inhibition effect of the mercapto group and the vinyl group during the ultraviolet light curing process, and improving the aging resistance of the silicone pressure-sensitive adhesive.

[0052] 6. The photocurable mercapto silicone resin prepared by the present invention has excellent transparency, and the visible light transmittance in the range of 400 - 800 nm exceeds 85%. Description of the Drawings

[0053] Figure 1 It is the FTIR spectrum diagram for characterizing the photocurable mercapto silicone resin of Examples 1 - 4.

[0054] Figure 2 It is for characterizing the photocurable mercapto silicone resin of Examples 1 - 4 1 1H-NMR spectrum diagram.

[0055] Figure 3 It is the ultraviolet-visible light transmittance diagram for characterizing the photocurable mercapto silicone resin of Examples 1 - 4.

[0056] Figure 4 It is the TGA spectrum diagram for the photocurable silicone pressure-sensitive adhesive of Examples 1 - 4. Detailed Embodiments

[0057] The following further describes the present invention in combination with the detailed embodiments and the drawings, but the present invention is not limited thereto. The methods involved in the present invention are all commonly used methods in the art unless otherwise specified, and the reagents involved can be obtained from ordinary commercial channels unless otherwise specified.

[0058] The present invention uses the following methods to characterize and test the performance of the following examples and comparative examples:

[0059] (1) Fourier Transform Infrared Spectroscopy (FTIR)

[0060] Using a Nicolet iS50 Fourier Transform Infrared Spectrometer manufactured by Thermo Fisher Scientific Company, Germany, through the KBr pellet method, the scanning wavelength range is 4000 - 600 cm -1 -1, the resolution is 4 cm -1 -1, and the number of scans is 32 times for the test.

[0061] (2) Nuclear Magnetic Resonance Hydrogen Spectrum ( 1H-NMR)

[0062] Using a Bruker AVANCE III 400 MHz Superconducting Fourier nuclear magnetic resonance spectrometer from Switzerland, the measurement conditions were at room temperature, and the solvent was deuterated chloroform (CDCl 3 ). And 1 The mercapto group content of the prepared mercapto silicone resin can be tested by the internal standard method of 3 H-NMR. At room temperature, 1,4-dioxane was used as the internal standard, and CDCl 3 was used as the solvent. Weigh a certain amount of the sample and 1,4-dioxane and mix them in CDCl

[0063]

[0064] In the formula, M SC is the molar fraction of mercaptopropyl in 100 g of the sample, mol / 100 g; W i is the mass of the internal standard 1,4-dioxane, g; W s is the mass of the sample, g; 88 is the relative molecular mass of 1,4-dioxane, g / mol; 8 is the number of H protons in 1,4-dioxane; 2 is the number of -CH 2 - protons connected to -SH in mercaptopropyl; A is the absorption peak area of -CH 2 - connected to -SH in mercaptopropyl; B is the peak area of -CH 2 - proton H in 1,4-dioxane.

[0065] (3) Refractive index: Tested using a 2WAJ Abbe refractometer from Shanghai Optical Instrument Factory according to GB / T 6448-2008.

[0066] (4) Viscosity: Tested using a DV2T rotational viscometer from Brookfield Company according to GB / T 10247-2008.

[0067] (5) Density: Tested using an AUY120 densitometer from Shimadzu Corporation of Japan according to the international standard ISO3521.

[0068] (6) Visible light transmittance: The transmittance in the wavelength range of 400 - 800 nm was tested using a UV-2450 ultraviolet-visible spectrophotometer from Shimadzu Corporation of Japan according to the standard method of ASTM D1003-13.

[0069] (7) TGA test: At room temperature, take about 5.00 - 10.00 mg of the sample in a clean ceramic crucible and test it using a TG 209F1 thermogravimetric analyzer from NETZSCH Company of Germany. The detection environment was N2 The flow rate is 20 mL / min, and the temperature is increased at a rate of 10 K / min to test the TGA curve of the sample in the range of 30 - 800 °C.

[0070] (8) Storage stability: According to GB / T 7123.2 - 2002, using viscosity as the index, the storage period is obtained, and the storage stability is compared based on the length of the storage period.

[0071] (9) Initial adhesion force test: Using the KJ - 6032 tape initial adhesion force testing machine of Guangdong Kejian Instrument Co., Ltd., test according to the inclined plane rolling ball method in GB / T 4852 - 2002.

[0072] (10) Holding adhesion force test: Using the KJ - 6012H constant temperature tape holding force testing machine of Guangdong Kejian Instrument Co., Ltd., test according to GB / T 4851 - 2014.

[0073] (11) Peel force test: Using the MK - BL - X tape speed 90° peel strength testing machine of Dongguan Maike Instrument Equipment Co., Ltd. for testing.

[0074] (12) Water - boiling aging resistance: Put the coated PET film into an 80 °C water bath, and test the initial adhesion force, holding adhesion force, 90° peel strength, and adhesion force at 0.5 h, 1 h, 1.5 h, and 2 h.

[0075] (13) Adhesion force: Test according to GB / T 9286 - 1998.

[0076] Example 1

[0077] (1) Preparation of MDQ photocurable mercapto - silicone resin

[0078] Add hexamethyldisiloxane (32.48 g, 0.20 mol), γ - mercaptopropylmethyldimethoxysilane (75.14 g, 0.42 mol), trifluoromethanesulfonic acid (0.62 g), and deionized water (21.00 g) into a four - necked flask equipped with a stirrer, thermometer, constant - pressure dropping funnel, and condenser. Stir and react at a constant temperature of 60 °C for 1 h. Then put tetraethyl orthosilicate (17.36 g, 0.08 mol) into the constant - pressure funnel and slowly drop it into the four - necked flask, and raise the temperature to 75 °C. After the dropping is completed, react at a constant temperature for 4 h. Subsequently, carry out vacuum distillation at - 0.1 MPa and 85 °C until it is completely transparent. Then remove the vacuum distillation device, pour the liquid in the flask into a separatory funnel, and wash it with a saturated Na 2 CO 3 ethanol solution. Rotate and evaporate the lower liquid obtained by separation after washing at - 0.1 MPa and 85 °C until it is completely transparent to obtain MDQ photocurable mercapto - silicone resin of Example 1.

[0079] IR analysis and 1 H-NMR analysis were performed on the prepared MDQ photocurable mercapto silicone resin. As shown in Figure 1 and Figure 2 , it conforms to the following general formula:

[0080] [(CH 3 ) 3 SiO 1 / 2 a [(CH 3 )(CH 2 CH 2 CH 2 SH)SiO 2 / 2 b [SiO 4 / 2 d

[0081] IR(cm -1 ):2950~2970(s, υ C-H , -CH 3 ), 2830~2860(s, υ C-H , -CH 2 -), 2565(s, υ S-H , -SH), 1350 and 1305(m, υ C-H , -CH 2 -), 1255(s, δ Si-C , Si-CH 3 ), 1030(s, υ Si-O , Si-O-Si), 810(s, δ S-H , -SH), 700~800(s, υ Si-C , Si-CH 3 ).

[0082] 1 H-NMR(δ ppm, CDCl 3 , 400 MHz): 3.68~3.73(d, 8H, dioxane), 3.47~3.50(d, H, -OH), 2.49~2.59(m, 2H, -SC H 2 CH 2 -), 1.60~1.74(m, 2H, -SCH 2 C H 2 -), 1.30~1.40(s, 1H, -SH), 0.56~0.72(m, 2H, -SiCH 2 -), -0.05~0.22(m, 3H, Si-CH 3 ).

[0083] (2) Preparation of MDQ photocurable silicone pressure-sensitive adhesive​​​

[0084] The MDQ photocurable mercapto silicone resin Example 1 (0.5 g) prepared above was mixed with terminal vinyl silicone oil (54.84 g, Vi mass fraction 0.12 wt.%, 25°C refractive index n: 1.46, 25°C viscosity of 10000 mPa·s, industrial grade, purity ≥ 99 wt.%, Guangzhou Shuangtao Fine Chemical Co., Ltd.), anchoring agent (1.66 g) and photoinitiator TPO-L (0.57 g) in a dark place, stirred evenly, and then vacuum degassed, and then coated on a 30 μm thick polyethylene terephthalate (PET) film, and the film was irradiated at a maximum intensity of 500 mW / cm 2 , under ultraviolet light in the wavelength range of 200-400 nm, a mercapto-ene photo-click reaction was carried out for 60 seconds to obtain MDQ photocurable silicone pressure-sensitive adhesive Example 1.

[0085] Example 2

[0086] (1) Preparation of MTQ photocurable mercapto silicone resin

[0087] Add hexamethyldisiloxane (40.60g, 0.25mol), γ-mercaptopropyltrimethoxysilane (49.09g, 0.25mol), and isopropanol (14.18g) into a four-necked flask connected to a stirrer, a thermometer, a constant pressure dropping funnel, and a condenser. Then, a mixture of concentrated hydrochloric acid (2.84g) and deionized water (25.20g) was placed into the constant pressure dropping funnel and slowly dripped into the four-necked flask at room temperature. After the addition was complete, ethyl orthosilicate (52.08g, 0.25mol) was placed into the constant pressure dropping funnel and slowly dripped into the four-necked flask, and the temperature was raised to 75°C. After the addition was complete, the reaction was kept at a constant temperature for 3 hours. Then the mixture was cooled to room temperature and anhydrous Na 2 CO 3 The powder was stirred for 45 minutes to remove the acid. Then, the mixture was subjected to rotary evaporation at -0.1 MPa and 85° C. until it was completely transparent. The mixture was filtered while hot to obtain a colorless, transparent viscous substance, namely, Example 2 of the MTQ light-cured mercapto silicone resin.

[0088] The MTQ photocurable mercapto silicone resin was analyzed by IR and 1 H-NMR analysis, such as Figure 1 , Figure 2 As shown, it conforms to the following general formula:

[0089] [(CH 3 ) 3 SiO 1 / 2 ] a [(CH 2 CH 2 CH 2 SH)SiO 3 / 2 ] c [SiO4 / 2 d

[0090] IR (cm -1 ):2875 - 2960 (s, υ C-H , -CH 3 ), 2933 (s, υ C-H , -CH 2 -), 2565 (s, υ S-H , -SH), 1435 (m, υ C-H , -CH 2 -), 1255 (s, δ Si-C , Si-CH 3 ), 1038 (s, υ Si-O , Si-O-Si), 755 - 841 (s, υ Si-C , Si-CH 3 )。

[0091] 1 H-NMR (δ ppm, CDCl 3 , 400 MHz): 3.68 - 3.75 (d, 8H, dioxane), 3.52 - 3.61 (d, H, -OH), 2.53 - 2.64 (m, 2H, -SCH 2 CH 2 -), 1.67 - 1.84 (s, 2H, -SCH 2 C H 2 -), 1.21 - 1.47 (d, 1H, -SH), 0.62 - 0.92 (s, 2H, -SiCH 2 -), 0.02 - 0.36 (m, 3H, Si-CH 3 )。

[0092] (2) Preparation of MTQ photocurable silicone pressure - sensitive adhesive

[0093] The prepared MTQ photocurable mercapto - silicone resin of Example 2 (0.5 g) was mixed with vinyl - terminated silicone oil (29.93 g, Vi mass fraction 0.12 wt.%, refractive index n at 25 °C: 1.46, viscosity at 25 °C: 10,000 mPa·s, industrial grade, purity ≥ 99 wt.%, Guangzhou Shuangtao Fine Chemical Co., Ltd.), anchoring agent (0.91 g) and photoinitiator TPO - L (0.31 g) in the dark and stirred evenly, then degassed under vacuum. Subsequently, it was coated on a polyethylene terephthalate (PET) film with a thickness of 30 μm, and then under ultraviolet light with a maximum irradiation intensity of 500 mW / cm 2 , wavelength range 200 - 400 nm, a thiol - ene photo - click reaction was carried out for 30 s to obtain MTQ photocurable silicone pressure - sensitive adhesive of Example 2. ​

[0094] Example 3

[0095] (1) Preparation of MDT photocurable mercapto silicone resin

[0096] Add hexamethyldisiloxane (8.12 g, 0.05 mol), dimethyldiethoxysilane (51.09 g, 0.35 mol) and γ-mercaptopropyltrimethoxysilane (9.82 g, 0.05 mol) into a four-necked flask equipped with a stirrer, a thermometer, a constant pressure dropping funnel and a condenser, and stir and react at a constant temperature of 60 °C for 1 h. Subsequently, trifluoromethanesulfonic acid (0.35 g) and deionized water (12.24 g) were loaded into the constant pressure funnel and slowly dropped into the four-necked flask, and the temperature was raised to 75 °C. After the dropping was completed, the reaction was carried out at a constant temperature for 2 h. Subsequently, distillation under reduced pressure was carried out at -0.1 MPa and 95 °C until it was completely transparent. After cooling to room temperature, anhydrous Na 2 CO 3 powder was added and stirred for 45 min to remove acid. Then, rotary evaporation was carried out at -0.1 MPa and 95 °C until it was completely transparent, and it was filtered while it was hot to obtain a colorless transparent viscous substance, namely MDT photocurable mercapto silicone resin of Example 3.

[0097] The prepared MDT photocurable mercapto silicone resin was subjected to IR analysis and 1 H-NMR analysis. As Figure 1 、 Figure 2 shown, it conforms to the following general formula:

[0098] [(CH 3 ) 3 SiO 1 / 2 a [(CH 3 ) 2 SiO 2 / 2 b [(CH 2 CH 2 CH 2 SH)SiO 3 / 2 c

[0099] IR(cm -1 ):2950~2970(s, υ C-H , -CH 3 ), 2830~2860(s, υ C-H , -CH 2 -), 2575(s, υ S-H , -SH), 1350 and 1305(m, υ C-H , -CH 2 -), 1255(s, δ Si-C , Si-CH 3 ​​​),1010(s, υ Si-O ,Si - O - Si), 686 and 789(s, υ Si-C ,Si - CH 3 )。

[0100] 1 H - NMR(δ ppm, CDCl 3 ,400 MHz): 3.69~3.76(d, 8H, dioxane), 2.49~2.61(m, 2H, - SCH 2 CH 2 - ), 1.65~1.77(m, 2H, - SCH 2 CH 2 - ), 1.26~1.39(s, 1H, - SH), 0.59~0.73(m, 2H, - SiCH 2 - ), 0.03~0.21(m, 3H, Si - CH 3 )。

[0101] (2) Preparation of MDT photocurable silicone pressure - sensitive adhesive

[0102] The prepared MDT photocurable mercapto - silicone resin of Example 3 (0.5 g) was mixed and stirred evenly with vinyl - terminated silicone oil (29.93 g, Vi mass fraction 0.12 wt.%, refractive index n at 25 °C: 1.46, viscosity at 25 °C: 10,000 mPa·s, industrial grade, purity ≥ 99 wt.%, Guangzhou Shuangtao Fine Chemical Co., Ltd.), anchoring agent (0.91 g) and photo - initiator TPO - L (0.31 g) in the dark, followed by vacuum degassing. Then it was coated on a polyethylene terephthalate (PET) film with a thickness of 30 μm, and then a thiol - ene photo - click reaction was carried out under ultraviolet light with a maximum irradiation intensity of 500 mW / cm2 and a wavelength range of 200 - 400 nm for 60 s to obtain MDT photocurable silicone pressure - sensitive adhesive of Example 3.

[0103] Example 4

[0104] (1) Preparation of DT photocurable mercapto - silicone resin

[0105] Add an appropriate amount of toluene (59.32 g) to a four-necked flask equipped with a stirrer, thermometer, constant pressure dropping funnel, and condenser. Subsequently, add diphenyldimethoxysilane (107.52 g, 0.44 mol), γ-mercaptopropyltrimethoxysilane (78.54 g, 0.44 mol), and methyltrimethoxysilane (38.97 g, 0.24 mol). When the oil bath is heated to 50 °C, load concentrated hydrochloric acid (3.95 g) and deionized water (40.32 g) into the constant pressure funnel and slowly drip them into the four-necked flask, and then raise the temperature to 75 °C - 80 °C. After the dropping is completed, react at a constant temperature for 3 h. Subsequently, cool to room temperature and wash with an ethanol solution saturated with Na 2 CO 3 . Wash the lower liquid obtained by liquid separation after washing and perform rotary evaporation at -0.1 MPa and 95 °C until it is completely transparent to obtain Example 4 of DT photocurable mercapto silicone resin.

[0106] Perform IR analysis and 1 1H-NMR analysis on the prepared DT photocurable mercapto silicone resin. As Figure 1 and Figure 2 shown, it conforms to the following general formula:

[0107] [Ph 2 SiO 2 / 2 b [(CH 2 CH 2 CH 2 SH)SiO 3 / 2 c1 [MeSiO 3 / 2 c2

[0108] IR (cm -1 -1): 3420 (s, υ Si-O , Si-OH), 3000 - 3070 (s, υ C-H , -C 6 H 5 ), 2960 - 2995 (s, υ C-H , -CH 3 ), 2846 (s, υ C-H , -CH 2 -), 2565 (s, υ S-H , -SH), 1430 and 1592 (s, υ C-C , -C 6 H 5 ), 1255 (s, δ Si-C , Si-CH 3 ), 1090 and 1190 (s, υ Si-O , Si-O-Si), 700 - 770 (s, δ​​​C-H , -C 6 H 5 ), 705~795(s, υ Si-C , Si-CH 3 )。

[0109] 1 H-NMR(δ ppm, CDCl 3 , 400 MHz): 7.17~7.87(m, 5H, Si-Ph), 3.63~3.75(d, 8H, dioxane), 3.47~3.53(d, H, -OH), 2.51~2.70(m, 2H, -SCH 2 CH 2 -), 1.57~1.87(s, 2H, -SCH 2 CH 2 -), 1.22~1.48(s, 1H, -SH), 0.68~1.01(s, 2H, -SiCH 2 -), 0.07~0.39(m, 3H, Si-CH 3 )。

[0110] (2) Preparation of DT photocurable silicone pressure-sensitive adhesive

[0111] The prepared DT photocurable mercapto silicone resin of Example 4 (0.5 g) was mixed and stirred evenly with vinyl-terminated silicone oil (29.93 g, Vi mass fraction 0.12 wt.%, refractive index n at 25 °C: 1.46, viscosity at 25 °C: 10,000 mPa·s, industrial grade, purity ≥ 99 wt.%, Guangzhou Shuangtao Fine Chemical Co., Ltd.), an anchoring agent (0.91 g), and a photoinitiator TPO-L (0.31 g) in the dark, followed by vacuum degassing. Then it was coated on a polyethylene terephthalate (PET) film with a thickness of 30 μm, and then a thiol-ene photo-click reaction was carried out under ultraviolet light with a maximum irradiation intensity of 500 mW / cm2 and a wavelength range of 200 - 400 nm for 60 s to obtain the DT photocurable silicone pressure-sensitive adhesive of Example 4.

[0112] Comparative Example 1

[0113] It is basically the same as Example 1, except that in this comparative example, butyl acetate solvent was added during the synthesis of the photocurable mercapto silicone resin. The specific steps are as follows:

[0114] Add hexamethyldisiloxane (32.48 g, 0.40 mol), concentrated hydrochloric acid (2.59 g), and deionized water (27.00 g) into a four-necked flask equipped with a stirrer, thermometer, constant pressure dropping funnel, and condenser. Stir and react at a constant temperature of 60 °C for 1 h. Then load γ-mercaptopropylmethyldimethoxysilane (45.09 g, 0.25 mol), tetraethyl orthosilicate (17.36 g, 0.08 mol), and butyl acetate (51.86 g, 0.45 mol) into the constant pressure funnel and slowly drop them into the four-necked flask. Then raise the temperature to 75 °C and keep reacting at a constant temperature for 7 h after the dropping is completed. Subsequently, carry out vacuum distillation at -0.1 MPa and 85 °C until it becomes completely transparent. After cooling to room temperature, add anhydrous Na 2 CO 3 powder and stir for 45 min to remove acid. Then carry out rotary evaporation at -0.1 MPa and 95 °C until it becomes completely transparent, and filter while it is hot to obtain a colorless transparent viscous substance, that is, the photocurable mercapto silicone resin comparative example 1. Then use the same method to prepare the photocurable silicone pressure-sensitive adhesive comparative example 1.

[0115] Comparative Example 2

[0116] It is basically the same as Example 4, except that dimethyldiethoxysilane is used in the synthesis of the photocurable mercapto silicone resin in this comparative example. The specific steps are as follows:

[0117] Pre-add an appropriate amount of toluene (54.82 g) into a four-necked flask equipped with a stirrer, thermometer, constant pressure dropping funnel, and condenser. Subsequently, add dimethyldiethoxysilane (65.24 g, 0.44 mol), γ-mercaptopropyltrimethoxysilane (78.54 g, 0.44 mol), and methyltrimethoxysilane (38.97 g, 0.24 mol). When the oil bath is heated to 50 °C, load concentrated hydrochloric acid (3.66 g) and deionized water (40.32 g) into the constant pressure funnel and slowly drop them into the four-necked flask, and raise the temperature to 75 °C - 80 °C. After the dropping is completed, keep reacting at a constant temperature for 3 h. Subsequently, cool to room temperature and wash with a saturated Na 2 CO 3 ethanol solution. Carry out rotary evaporation on the lower liquid obtained by liquid separation after washing at -0.1 MPa and 95 °C until it becomes completely transparent to obtain the photocurable mercapto silicone resin comparative example 2. Then use the same method to prepare the photocurable silicone pressure-sensitive adhesive comparative example 2.

[0118] Detect the relevant properties of the photocurable mercapto silicone resins prepared in Examples 1 - 4 and Comparative Examples 1 - 2, and the test results are shown in Table 1 and Figure 3 as follows.

[0119] Table 1:

[0120]

[0121] As shown in Table 1 and Figure 3 it can be seen that the photocurable mercapto silicone resin prepared by the present invention is a colorless and transparent viscous substance, without irritating gas, the visible light transmittance is greater than 85%, the mercapto content is 0.077 - 0.487 mol / 100 g, the refractive index is relatively high and the storage stability is high.

[0122] The relevant properties of the photocurable silicone pressure-sensitive adhesives prepared in Examples 1 - 4 were detected. The thermal stability and thermal decomposition process of the photocurable silicone pressure-sensitive adhesives in Examples 1 - 4 were tested by a thermogravimetric analyzer, and the obtained TGA curves are as Figure 4 shown, and the temperatures (5%, 50%, TMax) at different weight losses and the residual weight fraction at 800 °C were statistically analyzed, and the results are shown in Table 2.

[0123] Table 2:

[0124]

[0125] As Figure 4 shown, the weight of the photocurable silicone pressure-sensitive adhesives in Examples 1 - 4 of the present invention decreases with the increase of temperature, and the weight loss rate is relatively large in the range of 480 °C - 650 °C. The weight loss rate of the photocurable silicone pressure-sensitive adhesives of the present invention is above 400 °C when the weight loss rate is 5%, indicating that there is no obvious weight change before 400 °C. Obvious weight loss occurs when the temperature is above 520 °C. It can maintain a weight of 0.97% - 3.63% at a high temperature of 800 °C, showing good thermal stability.

[0126] The aging conditions of the photocurable silicone pressure-sensitive adhesives in Examples 1 - 4 and Comparative Example 1 under the condition of boiling water at 90 °C were tested, and the initial adhesion, holding adhesion, 90° peel strength and adhesion are shown in Table 3.

[0127] Table 3:

[0128]

[0129]

[0130] The photocurable silicone pressure-sensitive adhesives in Examples 1 - 4 and Comparative Example 1 were coated on a glass substrate, cured under ultraviolet light irradiation, and the bonding strength was tested at 180 °C or under high humidity conditions (the sample was completely immersed in water at room temperature), and the results are shown in Table 4.

[0131] Table 4:

[0132]

[0133] The results in the table show that in the thermal aging test at 180 °C for 3 h, the bonding strength of the silicone pressure-sensitive adhesive of the present invention did not show a significant decrease. Moreover, in the thermal aging test at 180 °C for 3 h, the bonding strength of Examples 1 and 2 even increased. The reason is that the residual unreacted mercapto groups during the photocuring process will further react and cure under the action of heat, thereby increasing the bonding strength. After the high-temperature test at 180 °C for 7 days, it still has a high bonding strength, excellent high-temperature resistance and aging resistance. And after the photocurable silicone pressure-sensitive adhesive was completely immersed in water at room temperature for 15 days, it can still maintain a bonding strength of more than 50%, with excellent weather resistance.

[0134] By comparing Example 1 and Comparative Example 1, it can be found that the original bonding strength of the photocurable silicone pressure-sensitive adhesive after adding butyl acetate solvent is lower than that of the solvent-free photocurable silicone pressure-sensitive adhesive, and the bonding strength in the thermal aging test at 180 °C for 7 days and the bonding strength in the moisture / 3 - 15-day weather resistance test both decreased significantly, and even the phenomena of debonding and degumming occurred.

[0135] It can be understood that the above specific embodiments are further descriptions of the present invention and are not used to limit the protection scope of the present invention. For those skilled in the art, all other retouches and modifications obtained without creative labor belong to the protection scope of the present invention.

Claims

1. A photocurable mercapto silicone resin, characterized in that: It conforms to the following general formula: [R 1 R 2 R 3 SiO 1 / 2 ] a [R 4 R 5 SiO 2 / 2 ] b [R 6 SiO 3 / 2 ] c [SiO 4 / 2 ] d ; Among them, R 1 , R 2 and / or R 3 is one or more of a hydrogen atom, a monovalent hydrocarbon group without an aliphatic unsaturated bond, or an unsaturated hydrocarbon group containing 2 to 10 carbon atoms; Among them, R 4 is methyl or phenyl, R 5 is one of methyl, phenyl, -CH2SH, -CH2CH2SH or -CH2CH2CH2SH, R 6 is one of -CH2SH, -CH2CH2SH or -CH2CH2CH2SH; Among them, a, b, c and d ≥ 0 and at most two of a, b, c and d are 0.

2. The photocurable mercapto silicone resin according to claim 1, characterized in that: In the general formula, when a≠0, a / (b+c+d)=0.6-1.

2.

3. The photocurable mercapto silicone resin according to claim 1, characterized in that: In the general formula, R 1 , R 2 and R 3 It is methyl.

4. The photocurable mercapto silicone resin according to claim 1, characterized in that: The photocurable mercapto silicone resin has a mercapto content of 0.07-0.49 mol / 100g.

5. The photocurable mercapto silicone resin according to claim 1, characterized in that: The photocurable mercapto silicone resin has a dynamic viscosity of 100-20000 mPa·s at 25° C., a refractive index of 1.40-1.49 at 25° C., and a visible light transmittance of ≥85%.

6. A method for preparing the photocurable mercapto silicone resin according to claim 1, characterized in that: The method comprises the following steps: reacting a silane monomer containing a hydrolyzable group, a capping agent and deionized water by a hydrolysis polycondensation method under the promotion of acid, alkali, salt or metal oxide to obtain the photocurable mercapto silicone resin.

7. The method for preparing the photocurable mercapto silicone resin according to claim 6, characterized in that: The silane monomer containing a hydrolyzable group includes a mercaptosilane monomer.

8. A light-curing silicone pressure-sensitive adhesive, characterized in that: The photocurable mercapto silicone resin is prepared from the photocurable mercapto silicone resin according to claim 1.

9. A method for preparing the light-curable silicone pressure-sensitive adhesive according to claim 8, characterized in that: The following steps are involved: The photocurable mercapto silicone resin, vinyl-terminated silicone oil, anchoring agent and photoinitiator are uniformly mixed and coated on a substrate, and crosslinked and cured by mercapto-ene photoclick chemistry under ultraviolet light to obtain the photocurable silicone pressure-sensitive adhesive.

10. Use of the photocurable mercapto silicone resin according to claim 1 or the photocurable organosilicon pressure-sensitive adhesive according to claim 8.

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