A polythiol compound containing a P heteroatom, an LED silicone encapsulant material and a preparation method thereof

Abstract

The application discloses a kind of P-containing polythiol compound, LED silicone encapsulating material and its preparation method, by introducing the hetero element such as sulfur, phosphorus with higher molar refractivity and smaller molar volume, and smaller dispersion coefficient, to effectively improve the refractive index of polymer, and have better light transmittance;At the same time, the design of unsymmetrical conjugated aromatic side group structure can reduce the crystallization rate of molecular chain, ensure the light transmittance of encapsulating material.The polythiol compound is dissolved in liquid mercapto crosslinking agent and vinyl organosilicon oligomer to occur mercapto-alkene free radical polymerization to prepare high light transmittance, high refractive index and high thermal stability organosilicon encapsulating material.

Description

Technical Field

[0001] This application relates to a multi-thiol compound containing P heteroatoms, an LED organosilicon encapsulation material, and a method for preparing the same, belonging to the field of organic chemical product technology. Background Technology

[0002] Light-emitting diodes (LEDs) are increasingly used in displays and lighting to create low-energy, environmentally friendly lighting devices. The development of LED packaging materials to protect the chip, leads, and other components has become a crucial issue for the commercial application of LEDs. Packaging materials prevent damage from environmental pollutants, humidity, static electricity, and physical impacts on the LED chip and fragile leads, significantly extending its lifespan. The energy efficiency of light emission depends on the transparency and refractive index of the sealant; therefore, a long-term stable sealant with good optical properties is essential.

[0003] Currently, epoxy resin and silicone resin are the main packaging materials in the commercial market. Epoxy resin has been the primary material for LED encapsulation for the past few decades. However, with the advent of high-power LEDs, the requirements for encapsulation materials are becoming increasingly stringent. In recent years, silicone materials have become a research hotspot due to their thermal stability, excellent heat resistance and UV resistance, and low surface energy, showing broad application prospects in LED encapsulation materials. Silicone resin is a low-crosslinking polysiloxane with a Si-O-Si main chain backbone and side groups that can contain different active groups (such as Si-CH=CH2, Si-OH, Si-OR, etc.). Because silicone combines the properties of both inorganic and organic materials, silicone rubber has higher thermal stability and higher oxidation resistance than other organic polymers.

[0004] The refractive index of a material is a measure of how light propagates through a medium. When light strikes the interface between two materials with different refractive indices, the light changes its speed and direction. In LEDs, the refractive index of the chip is between 2.5 and 4.0 (common GaN has a refractive index of 2.5), while the refractive index of the encapsulation material is generally around 1.5. This large difference in refractive index results in significant Fresnel loss as light passes through the chip / encapsulation interface, reducing the light extraction efficiency of the LED. To improve the light extraction efficiency of LEDs, it is necessary to increase the refractive index of the encapsulation material. Summary of the Invention

[0005] To address the aforementioned technical problems, improving the refractive index of organic polymers is a pressing issue that needs to be resolved. This application aims to improve the refractive index of organic polymers by introducing functional groups with high molar refractive index into the polymer chain, such as aromatic groups, halogen elements other than F, metal nanoparticles, and heteroelements such as sulfur, nitrogen, and phosphorus.

[0006] This application provides a multi-component thiol compound with an asymmetric conjugated aromatic side group structure containing P heteroatoms, which can be used in organosilicon encapsulation materials with high light transmittance, high refractive index and high thermal stability. This compound acts as a crosslinking agent, is dissolved in a liquid thiol crosslinking agent, and reacts with a vinyl-containing organosilicon resin to introduce P, S heteroelements and large conjugated groups into the organosilicon network, thereby preparing a high-refractive-index organosilicon encapsulation material.

[0007] This application provides an organosilicon encapsulation material with high light transmittance, high refractive index, and high thermal stability. The aforementioned phosphorus-containing polythiol compound can be used as a crosslinking agent to form CS bonds with vinyl organosilicon resin through a thiol-ene reaction, thereby forming an organosilicon encapsulation material with high light transmittance, high refractive index, and high thermal stability containing asymmetric conjugated aromatic side group structures of P and S heteroatoms.

[0008] When the amount of crosslinking agent containing a 5% asymmetric conjugated aromatic side group structure of P heteroatoms is used, the refractive index of the organosilicon encapsulation material can reach 1.5886, the visible light transmittance can reach up to 90%, and the thermal decomposition temperature can reach 346℃.

[0009] According to a first aspect of this application, a multi-functional thiol compound containing a P heteroatom is provided, the multi-functional thiol compound containing a P heteroatom having the structures shown in Formula I-1 and Formula I-2;

[0010]

[0011] R1 is selected from one of hydrogen atom, methyl, and phenyl;

[0012] R2, R3, R4, and R5 are independently selected from one of the following: hydrogen atom, C1-C6 alkyl group, C1-C6 alkoxy group, phenyl group, phenoxy group, and mercapto group;

[0013] R6, R7, R8, R9, R 10 R 11 It is independently selected from one of hydrogen atoms, methyl, and ethyl.

[0014] Optionally, in Formula I-1, R6 and R7 are independently selected from hydrogen atoms and methyl groups.

[0015] Alternatively, in Equation I-2, R8, R9, R 10 R 11 It is independently selected from either hydrogen atom or methyl group.

[0016] Optionally, the multi-thiol compound has the structure shown in Formula I-3;

[0017]

[0018] A1, A2, A3, and A4 are independently selected from H and methyl groups;

[0019] A5 is selected from H or methyl.

[0020] According to a second aspect of this application, a method for preparing the above-described polythiol compound containing a P heteroatom is provided, the method comprising the following steps:

[0021] (1) A mixture of phosphorus-containing hydrogen-bonded compounds, p-hydroxybenzaldehyde / ketone compounds, phenolic compounds, and an acidic catalyst, I, is reacted to obtain a phosphorus-containing polyhydroxy compound;

[0022] (2) A mixture of phosphorus-containing polyhydroxy compounds, thiocarbamate compounds, and an alkaline catalyst, II, is reacted to obtain O-aryl thiocarbamate.

[0023] (3) Mixture III containing O-aryl thiocarbamate was subjected to a Newman-Kwart rearrangement reaction to generate S-thiocarbamate.

[0024] (4) The mixture containing S-thiocarbamate IV was hydrolyzed to obtain a polythiol compound containing P heteroatoms.

[0025] Optionally, the phosphorus-containing hydrogen-bonded compound is selected from one having the structure shown in Formula II-1 and Formula II-2;

[0026]

[0027] In formula II-1, R6 and R7 are independently selected from one of hydrogen atoms, methyl, and ethyl.

[0028] In Equation II-2, R8, R9, R 10 R 11 It is independently selected from one of hydrogen atoms, methyl, and ethyl.

[0029] Optionally, R6 and R7 are hydrogen atoms.

[0030] Optionally, the p-hydroxybenzaldehyde / ketone compound is selected from those having the structure shown in Formula III;

[0031]

[0032] R1 is selected from one of hydrogen atom, methyl, and phenyl;

[0033] R2 and R3 are independently selected from one of hydrogen atom, C1-C6 alkyl group, C1-C6 alkoxy group, phenyl group, phenoxy group, and hydroxyl group.

[0034] Optionally, R2 and R3 are independently selected from one of hydrogen atom, methyl, ethyl, and hydroxyl.

[0035] Optionally, R2 and R3 are independently selected from hydrogen atoms and methyl groups.

[0036] Optionally, the phenolic compound is selected from one having the structure shown in Formula IV;

[0037]

[0038] R4 and R5 are independently selected from one of hydrogen atom, C1-C6 alkyl group, C1-C6 alkoxy group, phenyl group, phenoxy group, and hydroxyl group.

[0039] Optionally, R4 and R5 are independently selected from hydrogen atoms and methyl groups.

[0040] Optionally, the thiocarbamate compound is selected from at least one of N,N-dimethylthiocarbamate, N,N-diethylthiocarbamate, N-morphone, and N-methyl-N-phenylthiocarbamate.

[0041] Optionally, the thiocarbamate compound is N,N-dimethylthiocarbamate.

[0042] Optionally, in step (1), the molar ratio of the phosphorus-containing hydrogen-bonded compound, the p-hydroxybenzaldehyde / ketone compound, and the phenol compound is 1:1 to 1.5:3 to 6.

[0043] Optionally, the acidic catalyst is selected from at least one of p-toluenesulfonic acid, thionyl chloride, and oxalic acid.

[0044] Optionally, the mass ratio of the phosphorus-containing hydrogen-bonded compound to the acidic catalyst is 100:3 to 5.

[0045] Optionally, in step (1), the temperature of reaction I is 100-130°C and the reaction time is 12-36 h.

[0046] Optionally, the temperature of reaction I is selected from any value of 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃ or a range between any two of the above points.

[0047] Optionally, the reaction time I is selected from any value among 12h, 16h, 20h, 24h, 28h, 32h, and 36h, or a range between any two of the above points.

[0048] Optionally, in step (2), the molar ratio of the phosphorus-containing polyhydroxy compound, the thioformyl chloride compound, and the alkaline catalyst is 1:2.2-6:2.2-6.

[0049] Optionally, the base in the alkaline catalyst is selected from organic bases and / or inorganic bases.

[0050] Optionally, the organic base is selected from at least one of triethylenediamine, triethylamine, and pyridine.

[0051] Optionally, the inorganic base is selected from at least one of sodium hydride, sodium hydroxide, potassium hydroxide, and potassium carbonate.

[0052] Optionally, in step (2), the alkaline catalyst is selected from triethylenediamine and / or sodium hydride.

[0053] Optionally, the temperature of reaction II is 25–70°C, and the reaction time is 2–20 h.

[0054] Optionally, the temperature of reaction II is selected from any value among 25°C, 35°C, 45°C, 55°C, 65°C, and 70°C, or a range between any two of the above points.

[0055] Optionally, the reaction time II is selected from any value among 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, and 20h, or a range between any two of the above points.

[0056] Optionally, in step (3), the mixture III further includes solvent I, which is diphenyl ether.

[0057] Optionally, the rearrangement reaction is carried out at a temperature of 200–260°C for 2–24 hours.

[0058] Optionally, the temperature of the rearrangement reaction is selected from any value of 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃ or a range between any two of the above points.

[0059] Optionally, the time of the rearrangement reaction is selected from any value among 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, and 24h, or a range between any two of the above points.

[0060] Optionally, in step (4), the mixture IV further includes an alkali and a solvent.

[0061] Optionally, the solvent is selected from at least one of methanol, ethanol, 1,4-dioxane, dimethylformamide, and N-methyl-2-pyrrolidone.

[0062] Optionally, the solvent is methanol.

[0063] Optionally, the base is selected from sodium hydroxide and / or potassium hydroxide.

[0064] Optionally, the molar ratio of the S-thiocarbamate to the base is 1:3 to 10.

[0065] Optionally, in the hydrolysis reaction, the mass ratio of the solvent, alkali, and water is 40:6 to 20:0.3 to 1.

[0066] Optionally, the hydrolysis reaction is carried out at a temperature of 60–120°C for 2–8 hours.

[0067] Optionally, the temperature of the hydrolysis reaction is selected from any value of 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃ or a range between any two of the above points.

[0068] Optionally, the hydrolysis reaction time is selected from any value among 2h, 3h, 4h, 5h, 6h, 7h, and 8h, or a range between any two of the above points.

[0069] According to a third aspect of this application, an LED silicone encapsulation material is provided, the LED silicone encapsulation material comprising crosslinking agent A, crosslinking agent B, silicone resin and initiator;

[0070] The crosslinking agent A is selected from one of the above-described polythiol compounds containing P heteroatoms and the polythiol compounds containing P heteroatoms prepared by the above-described preparation method;

[0071] The crosslinking agent B is selected from one having the structure shown in Formula V;

[0072]

[0073] R 12 R 13 It is independently selected from one of methyl, phenyl, and -O(CH)2SH.

[0074] Optionally, R 12 R 13 It is independently selected from phenyl and -O(CH)2SH.

[0075] Optionally, the silicone resin is selected from at least one of vinyl silicone resins.

[0076] Optionally, the vinyl-containing silicone resin is selected from at least one of terminal vinyl polydimethylsiloxane, terminal vinyl polymethylvinylsiloxane, phenyl vinyl polysiloxane, and methylphenyl vinyl polysiloxane.

[0077] Optionally, the initiator is selected from one of benzoin, BDK, DEAP, HMPP, HCPK, HHMP, MMMP, BDMB, MBF, TEPO, TPO, BMS, Irgacure 500, Irgacure 1000, and UV6174.

[0078] Optionally, the initiator is selected from HCPK and BDK.

[0079] Optionally, the preparation method includes: dissolving crosslinking agent A in crosslinking agent B in the presence of an initiator, then mixing it with organosilicon resin, and curing it under ultraviolet light to obtain the LED organosilicon encapsulation material.

[0080] Optionally, the mass ratio of the crosslinking agent A, crosslinking agent B, and initiator is 1-5:100:0.5-2.

[0081] Optionally, the molar ratio of the functional groups of the organosilicon resin to the crosslinking agent is 1:0.9 to 1.1.

[0082] Optionally, the UV curing time is 5 to 60 minutes.

[0083] Optionally, the UV curing time is selected from any value among 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 40 min, 50 min, and 60 min, or a range between any two of the above points.

[0084] Optionally, the preparation method of the crosslinking agent B includes:

[0085] In an inactive atmosphere, a mixture containing 2-5 parts of a furic acid agent, 2-5 parts of a mercapto alcohol compound, 1 part of a chlorosilane compound, and a solvent is reacted to obtain the crosslinking agent B.

[0086] Optionally, the flavonoid is selected from at least one of diethylamine, triethylamine, N,N-diisopropylethylamine, 4-dimethylaminopyridine, and pyridine.

[0087] Optionally, the mercapto alcohol compound is β-mercaptoethanol.

[0088] Optionally, the chlorosilane compound is selected from at least one of phenyltrichlorosilane, methyltrichlorosilane, diphenyldichlorosilane, dimethyldichlorosilane, and methylphenyldichlorosilane.

[0089] Optionally, the solvent is selected from at least one of diethyl ether, tetrahydrofuran, and dioxane;

[0090] Optionally, the volume ratio of the acid-binding agent to the solvent is 1:20 to 30.

[0091] Optionally, the reaction temperature is 0–50°C, and the reaction time is 5–14 h.

[0092] Optionally, the temperature of the reaction is selected from any value of 0°C, 15°C, 25°C, 35°C, 50°C, or a range between any two of the above points.

[0093] Optionally, the reaction time is selected from any value among 5h, 8h, 10h, 12h, and 14h, or a range between any two of the above points.

[0094] Optionally, the inactive atmosphere is selected from at least one of nitrogen, helium, neon, and argon.

[0095] Optionally, when the crosslinking agent A accounts for 5% of the mass of the crosslinking agent B, the refractive index of the LED silicone encapsulation material is 1.5886, the visible light transmittance reaches more than 90%, and the thermal decomposition temperature is 346℃.

[0096] In this application, C1 to C6 refer to the number of carbon atoms contained in the group.

[0097] In this application, the term "alkyl" refers to a group formed by the loss of any one hydrogen atom from an alkane molecule.

[0098] In this application, the term "alkoxy" refers to an alkoxy group in which an alkyl portion, as defined above as "alkyl", is bonded to an oxygen atom.

[0099] In this application, the term "phenyl" refers to a group formed by losing any one hydrogen atom from a benzene ring.

[0100] In this application, the term "phenoxy" refers to the group formed by the loss of a hydrogen atom from the hydroxyl group in a phenol molecule.

[0101] In this application, the term "thiol" refers to a group consisting of a sulfur atom and a hydrogen atom bonded together.

[0102] The beneficial effects that this application can produce include:

[0103] 1) The multi-thiol compound containing asymmetric conjugated aromatic side group structure with P heteroatom provided in this application and its preparation method introduce large conjugated groups and sulfur and phosphorus heteroatoms through thiol-double bond reaction, thereby forming an organosilicon encapsulation material with high light transmittance, high refractive index and high thermal stability.

[0104] 2) This application effectively improves the refractive index of the polymer and provides good light transmittance by introducing impurities such as sulfur and phosphorus, which have high molar refractive index, small molar volume, and low dispersion coefficient. Simultaneously, the design of the asymmetric pair-junction conjugated aromatic side group structure reduces the crystallinity of the molecular chain, ensuring the light transmittance of the encapsulation material. This multi-thiol compound is prepared by thiol-alkene free radical polymerization with a vinyl organosilicon oligomer dissolved in a liquid thiol crosslinking agent to produce an organosilicon encapsulation material with high light transmittance, high refractive index, and high thermal stability.

[0105] 3) The phosphorus-containing multi-thiol compound in this application can be used as a crosslinking agent for vinyl silicone resin to form CS bonds through a thiol-ene reaction, thereby forming a silicone encapsulation material with high light transmittance, high refractive index and high thermal stability with an asymmetric conjugated aromatic side group structure containing P and S heteroatoms: when the amount of the multi-thiol compound crosslinking agent with an asymmetric conjugated aromatic side group structure containing P heteroatoms is 5%, the refractive index of the silicone encapsulation material can reach as high as 1.5886, the visible light transmittance can reach up to 90%, and the thermal decomposition temperature can reach 346℃. Attached Figure Description

[0106] Figure 1 This is the nuclear magnetic resonance spectrum of phosphorus-containing dithiol compound A1 in Example 1 of this application.

[0107] Figure 2 This is the nuclear magnetic resonance spectrum of phosphorus-containing dithiol compound A2 in Example 2 of this application.

[0108] Figure 3 This is a refractive index test diagram of Example 4 of this application.

[0109] Figure 4 This is a refractive index test diagram of Example 5 of this application.

[0110] Figure 5 The light transmittance of Examples 4 and 5 of this application at different wavelengths.

[0111] Figure 6 The thermogravimetric curves are for Examples 4 and 5 of this application. Detailed Implementation

[0112] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0113] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0114] In the embodiments of this application, "room temperature" refers to "25°C".

[0115] The analysis method in the embodiments of this application is as follows:

[0116] The scanning was performed in the wavelength range of 300–800 nm using a Lambda 950 UV-Vis-NIR spectrophotometer.

[0117] The refractive index of organosilicon thin films was measured using a Models2010 / M prism coupler.

[0118] The proton nuclear magnetic resonance spectrometer was used for analysis.

[0119] Thermogravimetric analysis was performed using a STA449C thermogravimetric analyzer.

[0120] In this application, the p-heteroatom-containing polythiol compound is synthesized and prepared through the following steps:

[0121] a) First, a phosphorus-containing polyhydroxy compound is prepared by P(O)-H and C=O addition reaction of a phosphorus-containing hydrogen bond compound and a p-hydroxybenzaldehyde (ketone) compound. Then, a phosphorus-containing polyhydroxy compound is prepared by dehydration condensation with a phenol compound in the presence of an acidic catalyst.

[0122] b) Phosphorus-containing polyhydroxy compounds react with thiocarbamate compounds to form O-aryl thiocarbamates;

[0123] c) O-aryl thiocarbamate is then subjected to Newman-Kwart rearrangement and hydrolysis to yield polythiol compounds.

[0124] Optionally, phosphorus-containing polyhydroxy compounds are obtained by condensation reaction of a mixed reaction system of a phosphorus-containing hydrogen bond compound, a p-hydroxybenzo(aldehyde) ketone compound and a phenol compound, and an acidic catalyst at 100–130 °C for 12–36 h under an inactive gas protective atmosphere.

[0125] Optionally, in step b), the O-aryl thiocarbamate is obtained by esterification of the phosphorus-containing polyhydroxy compound and thiocarbamate obtained in step a) under the action of an alkaline catalyst.

[0126] The reaction mechanism is shown in the figure below:

[0127]

[0128] Optionally, in step c), the multi-thiol compound containing P heteroatoms is obtained by first generating S-thiol carbamate from the O-aryl thiocarbamate obtained in step b) through Newman-Kwart rearrangement at high temperature, and then obtaining the multi-thiol compound through ester hydrolysis under strong base.

[0129] The reaction mechanism is shown in the figure below:

[0130]

[0131] The Newman-Kwart rearrangement of the O-aryl thiocarbamate is obtained by reacting at 200-260°C for 2-24 hours. This rearrangement reaction can be carried out under solvent-free conditions or with diphenyl ether as the solvent.

[0132] Optionally, the solvent used in the ester hydrolysis reaction of the S-thiocarbamate is at least one of methanol, ethanol, 1,4-dioxane, dimethylformamide, and N-methyl-2-pyrrolidone.

[0133] Optionally, the alkali used in the hydrolysis reaction is either sodium hydroxide or potassium hydroxide.

[0134] Optionally, the molar ratio of S-thiocarbamate to base is 1:3 to 10.

[0135] In this application, the preparation method of the high refractive index silicone resin encapsulation material is as follows: a multi-thiol compound with an asymmetric conjugated aromatic side group structure containing P heteroatoms in crosslinking agent A is dissolved in a liquid multi-thiol monomer in crosslinking agent B, and then mixed evenly with vinyl silicone resin. Under the condition of an initiator, the mixture is cured with ultraviolet light to obtain the LED silicone encapsulation material.

[0136] In this application, a method for preparing a liquid multi-thiol monomer is described as follows: 2-5 parts of a fucoidic acid agent and 2-5 parts of a mercapto alcohol compound are dissolved in an appropriate amount of anhydrous diethyl ether solution. Under an inert gas atmosphere and at low temperature, 1 part of a chlorosilane compound is slowly added. After the addition is complete, the temperature is gradually raised to room temperature, and the reaction continues for 5-14 hours. The reaction solvent is then evaporated after filtration. The multi-thiol compound is obtained by vacuum distillation.

[0137] Example 1: Synthesis of phosphorus-containing dithiol compound A1

[0138] 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) (10.809 g, 0.05 mol), p-hydroxybenzaldehyde (6.106 g, 0.05 mol), phenol (22.528 g, 0.25 mol), and p-TSA (0.432 g, 4.0 wt% of DOPO) were added to a 250 mL three-necked flask. The mixture was stirred at 130 °C for 24 h under a nitrogen atmosphere. After the reaction was stopped, the mixture was cooled to room temperature, filtered, and excess phenol was removed by washing with ethanol. The solution was dried under vacuum to give a white solid, Ala.

[0139] A1a (10.3600 g, 0.025 mol) and the basic catalyst triethylenediamine (DABCO) (11.2170 g, 0.1 mol) were dissolved in 100 ml of anhydrous DMF in a 250 ml flask. The mixture was stirred under a nitrogen atmosphere until completely dissolved, and then N,N-dimethylthiocarbamoyl chloride (DMTCC) (12.3604 g, 0.1 mol) was added. The mixture was stirred overnight at room temperature. The reaction was quenched with ice water, resulting in the formation of a white solid. This solid was filtered, washed several times with water, and dried under vacuum to obtain solid A1b.

[0140] A1b (14.0106 g, 23.8 mmol) and diphenyl ether (40 g) were added to a 100 mL three-necked flask and reacted at 260 °C for 2 h under a N2 atmosphere. After the reaction was complete, the mixture was cooled to room temperature and washed several times with methanol. It was then recrystallized from dichloromethane and methanol to obtain a white powder, A1c.

[0141] The rearranged diester A1c (7.0642 g, 12 mmol) was added to 7.08 g (0.108 mol) of 85% potassium hydroxide dissolved in 0.42 mL of water and 20.4 mL of methanol. The mixture was refluxed for 1 h. The solution was diluted with water to 108 mL, and 13.2 mL of hydrochloric acid was added. The precipitated dithiol was filtered off and dried under vacuum to obtain a white powder, A1. Figure 1 As can be seen, the absorption peaks at 6.7-8.0 ppm are for hydrogen atoms on the benzene ring, at 4.45 ppm is for the PCH bond, and at 5.30 ppm is for the -SH bond. Furthermore, the integral areas at these three locations are calculated to be 16:1:2, which is the same as the integral values ​​of the target structure, indicating that compound A1 was successfully synthesized.

[0142] Example 2: Synthesis of phosphorus-containing dithiol compound A2

[0143] DOPO (10.809 g, 0.05 mol), p-hydroxybenzaldehyde (6.106 g, 0.05 mol), o-cresol (27.035 g, 0.25 mol), and p-TSA (0.432 g, 4.0 wt% of DOPO) were added to a 250 mL three-necked flask. The mixture was stirred at 130 °C for 24 h under a nitrogen atmosphere. After the reaction was stopped, the mixture was cooled to room temperature, filtered, and washed with ethanol to remove excess phenol. The solution was dried under vacuum to give a white solid, A2a.

[0144] A2a (10.3600 g, 0.025 mol) and the basic catalyst triethylenediamine (DABCO) (11.2170 g, 0.1 mol) were dissolved in 100 mL of anhydrous DMF in a 250 mL flask. The mixture was stirred under a nitrogen atmosphere until completely dissolved. Then, N,N-dimethylthiocarbamoyl chloride (DMTCC) (12.3604 g, 0.1 mol) was added. The mixture was stirred overnight at room temperature. The reaction was quenched with ice water, resulting in the formation of a white solid. This solid was filtered, washed several times with water, and purified by column chromatography to obtain solid A2b.

[0145] A2b (14.0106 g, 23.8 mmol) and diphenyl ether (40 g) were added to a 100 mL three-necked flask and reacted at 260 °C for 2 h under a N2 atmosphere. After the reaction was complete, the mixture was cooled to room temperature and purified by column chromatography to obtain a white powder, A2c.

[0146] The rearranged diester A2c (7.0642 g, 12 mmol) was added to 7.08 g (0.108 mol) of 85% potassium hydroxide dissolved in 0.42 mL of water and 20.4 mL of methanol. The mixture was refluxed for 1 h. The solution was diluted to 108 mL with water, and 13.2 mL of hydrochloric acid was added. The precipitated dithiol was filtered off and dried under vacuum to obtain a white powder A2. Figure 2 As can be seen, the absorption peaks at 7.83–6.92 ppm are for hydrogen atoms on the benzene ring, and the absorption peak at 3.96 ppm is for the PCH bond. The absorption peaks at 5.27 ppm and 5.02 ppm are for -SH. Furthermore, the integral area calculations at these four locations show an integral ratio of 16:1:1:1, which is the same as the integral value of the target structure, indicating that compound A2 was successfully synthesized.

[0147] Example 3: Preparation of liquid multi-thiol compound B1

[0148] 400 mL of diethyl ether, 18.2 mL of triethylamine (0.13 mol), and 9.20 mL of 2-mercaptoethanol (0.13 mol) were placed in a 1 L round-bottom flask with three necks. The solution was cooled in an ice bath under nitrogen atmosphere with stirring. 7.00 mL of phenyltrichlorosilane (0.044 mol) was slowly added to the stirred solution. The suspension was gradually heated to room temperature and stirred overnight under nitrogen atmosphere. The suspension was filtered under vacuum, using diethyl ether as the washing solution. All volatiles were removed from the filtrate by rotary evaporation to obtain an oily substance, which was then purified by vacuum distillation to obtain a clear, colorless liquid, namely dimercapto-B1.

[0149] Example 4: Preparation of organosilicon film C1 with a 0% crosslinking agent for a polythiol compound containing asymmetric conjugated aromatic side groups of P heteroatoms.

[0150] 0.3365 g of ternary mercapto compound liquid B1, 1 g of vinyl organosilicon oligomer (0.003 mol / g), and 0.0020 g of photoinitiator (specifically, photoinitiator 184) were mixed evenly and defoamed under vacuum. The mixture was then cured in a UV curing oven for 10 min to obtain a colorless and transparent organosilicon film.

[0151] Preparation method of vinyl organosilicon oligomers: Methylvinyl dimethoxysilane (2.6446 g) and diphenylsilanediol (4.3262 g) were added to a flask as precursors for the synthesis of linear vinyl oligomeric siloxane resins, and barium hydroxide monohydrate (0.0068 g) was added as an alkaline catalyst to promote the reaction. The reaction was carried out at 60 °C for 12 hours, followed by 80 °C for 12 hours, to synthesize the organosilicon resin. The specific structure is as follows:

[0152]

[0153] from Figure 3 As can be seen, the refractive index of the organosilicon film C1 with 0% crosslinking agent of the multi-thiol compound containing the asymmetric conjugated aromatic side group structure of P heteroatom is 1.5853.

[0154] from Figure 5 As can be seen from the data, the organosilicon film C1 with an organosilicone crosslinking agent of 0% containing asymmetric conjugated aromatic side group structure of P heteroatoms has the highest light transmittance of over 90% in the visible light range.

[0155] from Figure 6 As can be seen from the data, the 5% thermal weight loss temperature of the organosilicon film C1 with a crosslinking agent containing asymmetric conjugated aromatic side groups of P heteroatoms is 358℃ when the amount of crosslinking agent used is 0%.

[0156] Example 5: Preparation of organosilicon film C2 with a 5% crosslinking agent for a polythiol compound containing asymmetric conjugated aromatic side groups of P heteroatoms.

[0157] 0.3365g of ternary thiol compound liquid B1 and 0.0168g of dithiol compound A1 were mixed and dissolved. Then, 1g of vinyl organosilicon oligomer (0.003mol / g) and 0.0020g of photoinitiator (specifically, photoinitiator 184) were added and mixed thoroughly, followed by vacuum defoaming. The mixture was cured in a UV curing oven for 10 minutes to obtain a colorless and transparent organosilicon film. Figure 4 As can be seen, the refractive index of the organosilicon film C2, with a crosslinking agent containing a 5% amount of asymmetric conjugated aromatic side group structure of a polythiol compound containing p heteroatoms, is 1.5886. From... Figure 5As can be seen, the organosilicon film C2 with a crosslinking agent containing 5% of the asymmetric conjugated aromatic side group structure of the P heteroatom has the highest light transmittance of over 90% in the visible light range.

[0158] from Figure 6 As can be seen from the data, the 5% thermal weight loss temperature of the organosilicon film C2 with a crosslinking agent containing a 5% amount of asymmetric conjugated aromatic side group structure of P heteroatoms is 346℃.

[0159] Example 6: Performance Testing of Organosilicon Films

[0160] from Figure 5 As can be seen, the prepared organosilicon films C1 and C2 have excellent light transmittance, with light transmittance of about 90% in the visible light range.

[0161] Table 1. Refractive index and thermogravimetric temperature of samples C1 and C2

[0162] Sample number Refractive index <![CDATA[T 5％ (℃)]]> C1 1.5853 358 C2 1.5886 350

[0163] As can be seen from Table 1, the prepared C1 and C2 have excellent refractive index and thermal stability, and the refractive index of C2 is higher than that of C1.

[0164] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An LED silicone encapsulation material, characterized in that, The LED silicone encapsulation material includes crosslinking agent A, crosslinking agent B, silicone resin, and initiator; The crosslinking agent A is a multi-functional thiol compound containing p-heteroatoms with the structure shown in Formula I-3, and has an asymmetric conjugated aromatic side group structure: Equation I-3; Among them, A1, A2, A3, and A4 are independently selected from H and methyl; A5 is selected from H and methyl. The crosslinking agent B is selected from one having the structure shown in Formula V; Formula V; R 12 R 13 Independently selected from phenyl, -O(CH2)2SH; The silicone resin is selected from silicone resins containing vinyl groups; The initiator is HCPK; The mass ratio of the crosslinking agent A, crosslinking agent B, and initiator is 1~5:100:0.5~2.

2. The method for preparing the LED organosilicon encapsulation material according to claim 1, characterized in that, The preparation method includes: In the presence of an initiator, crosslinking agent A is dissolved in crosslinking agent B, then mixed with silicone resin, and cured under ultraviolet light to obtain the LED silicone encapsulation material. The functional group molar ratio of the organosilicon resin to the crosslinking agent is 1:0.9~1.1; The UV curing time is 5~60 minutes.

3. The preparation method according to claim 2, characterized in that, The crosslinking agent A is prepared by the following steps: (1) A mixture of phosphorus-containing hydrogen-bonded compounds, p-hydroxybenzaldehyde / ketone compounds, phenolic compounds, and an acidic catalyst, I, is reacted to obtain a phosphorus-containing polyhydroxy compound; (2) A mixture of phosphorus-containing polyhydroxy compound, thiocarbamate compound, and alkaline catalyst is reacted to obtain O-aryl thiocarbamate; wherein the thiocarbamate compound is of formula I-4. Equation I-4; (3) Mixture III containing O-aryl thiocarbamate was subjected to a Newman-Kwart rearrangement reaction to generate S-thiocarbamate; (4) The mixture containing S-thiocarbamate IV was hydrolyzed to obtain a polythiol compound containing P heteroatoms; The phosphorus-containing hydrogen-bonded compound is II-1; Formula II-1; In formula II-1, R6 and R7 are both hydrogen atoms; The p-hydroxybenzaldehyde / ketone compound is selected from one having the structure shown in Formula III; Formula III; R1 is selected from either hydrogen atom or methyl group; R2 and R3 are independently selected from hydrogen atoms and methyl groups; The phenolic compound is selected from one having the structure shown in Formula IV; Formula IV; R4 and R5 are independently selected from either hydrogen or methyl.

4. The preparation method according to claim 3, characterized in that, In step (1), the molar ratio of the phosphorus-containing hydrogen bond compound, the p-hydroxybenzaldehyde / ketone compound, and the phenol compound is 1:1~1.5:3~6; The acidic catalyst is selected from at least one of p-toluenesulfonic acid, thionyl chloride, and oxalic acid; The mass ratio of the phosphorus-containing hydrogen-bonded compound to the acidic catalyst is 100:3~5; In step (1), the temperature of reaction I is 100~130℃ and the reaction time is 12~36h.

5. The preparation method according to claim 3, characterized in that, In step (2), the molar ratio of the phosphorus-containing polyhydroxy compound, the thioformyl chloride compound, and the alkaline catalyst is 1:2.2~6:2.2~6; The base in the alkaline catalyst is selected from organic bases and / or inorganic bases; The organic base is selected from at least one of triethylenediamine, triethylamine, and pyridine; The inorganic base is selected from at least one of sodium hydride, sodium hydroxide, potassium hydroxide, and potassium carbonate; The temperature of reaction II is 25~70℃, and the reaction time is 2~20h.

6. The preparation method according to claim 3, characterized in that, In step (3), the mixture III further includes solvent I, which is diphenyl ether; The rearrangement reaction is carried out at a temperature of 200~260℃ for 2~24h. In step (4), the mixture IV also includes an alkali and a solvent; The solvent is selected from at least one of methanol, ethanol, 1,4-dioxane, dimethylformamide, and N-methyl-2-pyrrolidone; The base is selected from sodium hydroxide and / or potassium hydroxide; The molar ratio of the S-thiocarbamate to the base is 1:3~10; In the hydrolysis reaction, the mass ratio of solvent, alkali, and water is 40:6~20:0.3~1; The hydrolysis reaction is carried out at a temperature of 60~120℃ for 2~8 hours.

7. The preparation method according to claim 2, characterized in that, The preparation method of the crosslinking agent B includes: In an inactive atmosphere, a mixture containing 2-5 parts of an acid-binding agent, 2-5 parts of a mercapto alcohol compound, 1 part of a chlorosilane compound, and a solvent is reacted to obtain the crosslinking agent B, based on molar proportions. The acid-binding agent is triethylamine; The mercapto alcohol compound is β-mercaptoethanol; The chlorosilane compound is phenyltrichlorosilane; The solvent is diethyl ether; The volume ratio of the acid-binding agent to the solvent is 1:20~30; The reaction temperature is 0~50℃, and the reaction time is 5~14h; The inactive atmosphere is selected from at least one of nitrogen, helium, neon, and argon.

8. The LED silicone encapsulation material according to claim 1, characterized in that, When the crosslinking agent A accounts for 5% of the mass of the crosslinking agent B, the refractive index of the LED silicone encapsulation material is 1.5886, the visible light transmittance reaches a maximum of 90%, and the thermal decomposition temperature is 346℃.

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