Preparation method of LED lamp bead rubber sleeve

Abstract

The invention discloses a preparation method of an LED lamp bead rubber sleeve, which comprises the following steps: weighing the following raw materials: 100-120 parts of functional resin, 5-10 parts of modified boron nitride, 1-3 parts of a modified additive, 10-15 parts of triethylene tetramine and 0.1-0.3 part of ammonium persulfate, uniformly mixing the raw materials, injecting into a mold, and carrying out heating and heat preservation treatment to obtain the LED lamp bead rubber sleeve. When the raw materials are mixed and heated, an epoxy group on the functional resin reacts with triethylene tetramine to form a grid structure, and under the action of ammonium persulfate, double bonds on a side chain of the functional resin, double bonds on the modified boron nitride and double bonds on the modified additive are subjected to free radical polymerization, so that a compact interpenetrating network is formed by a molecular structure; meanwhile, a main chain is a polysiloxane chain segment, so that the prepared rubber sleeve has a very good high-temperature-resistant oxidation effect, and a hindered amine structure on the modified additive can continuously capture and neutralize free radicals causing thermal oxidation of epoxy resin.

Description

Technical Field

[0001] This invention relates to the field of adhesive sleeve preparation technology, and specifically to a method for preparing an adhesive sleeve for LED beads. Background Technology

[0002] As a new generation of solid-state light source, the performance and lifespan of LEDs depend not only on the chip itself but also on the encapsulation and protection materials. The LED chip sleeve, or encapsulation colloid, is a crucial material directly covering the LED chip, undertaking multiple core functions such as protecting the chip and circuitry, dissipating heat, optical matching, insulation protection, and resisting environmental corrosion. Traditional LED encapsulation widely uses epoxy resin, which has become mainstream due to its excellent adhesion, high insulation, ease of processing, and low cost. However, as LED technology develops towards higher power, higher brightness, and smaller size, and as applications expand to demanding fields such as outdoor lighting and automotive headlights, the inherent defects of traditional epoxy resin are becoming increasingly prominent, especially facing severe challenges in long-term thermo-oxidative aging performance. Research shows that under long-term heat and ultraviolet light, the molecular chains of conventional epoxy resin are prone to oxidative degradation, manifesting as colloid yellowing, decreased light transmittance, increased brittleness, and interface delamination, ultimately leading to LED light output attenuation, color temperature drift, and even failure. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing LED bead sleeves, which solves the problem of poor heat aging resistance of current LED bead sleeves.

[0004] The objective of this invention can be achieved through the following technical solutions: A method for preparing an LED lamp bead sleeve specifically includes the following steps: Step A1: Dissolve D-glucose in deionized water, stir and add hexagonal boron nitride at a speed of 200-300 r / min and a temperature of 25-30℃, and stir for 2-3 hours to obtain pretreated boron nitride. Mix the pretreated boron nitride, ethanol and deionized water evenly, stir and add methacryloxypropyltrimethoxysilane at a speed of 150-200 r / min and a temperature of 75-80℃, and react for 5-7 hours to obtain modified boron nitride. Step A2: Mix modified epoxy resin, cis-5-dodecenoic acid, hydroquinone and xylene, purge with nitrogen, stir and add p-toluenesulfonic acid pyridine salt under the conditions of 150-200 r / min and 70-80℃, and react for 6-8 hours to obtain functionalized resin. Step A3: Mix cyanuric chloride and anhydrous acetone, stir at 200-300 r / min and 0-5℃, and add 1,2,2,6,6-pentamethylpiperidinol, sodium hydroxide aqueous solution and tetrabutylammonium bromide. React for 2-3 h, raise the temperature to 40-50℃ and continue the reaction for 4-6 h, raise the temperature to 80-90℃, add allyl alcohol and hydroquinone, and continue the reaction for 3-5 h to obtain the modified additive. Step A4: Weigh the following raw materials in parts by weight: 100-120 parts of functionalized resin, 5-10 parts of modified boron nitride, 1-3 parts of modified additives, 10-15 parts of triethylenetetramine, and 0.1-0.3 parts of ammonium persulfate. Mix the raw materials evenly and inject them into the mold. After heat treatment at 60-70℃ for 1-1.5 hours, raise the temperature to 110-120℃ and heat treatment for 6-8 hours to obtain LED lamp bead sleeves.

[0005] Furthermore, in step A1, the ratio of D-glucose solution, deionized water, and hexagonal boron nitride is 15g:20mL:3g, and the amount of methacryloyloxypropyltrimethoxysilane is 5% of the mass of the pretreated boron nitride.

[0006] Furthermore, in step A2, the molar ratio of hydroxyl groups on the modified epoxy resin to cis-5-dodecenoic acid is 1:1, the amount of hydroquinone used is 0.05-0.1% of the mass of cis-5-dodecenoic acid, and the amount of p-toluenesulfonic acid pyridine salt used is 3% of the mass of cis-5-dodecenoic acid.

[0007] Furthermore, in step A3, the ratio of cyanuric chloride, 1,2,2,6,6-pentamethylpiperidinol, sodium hydroxide aqueous solution, tetrabutylammonium bromide, and allyl alcohol is 1 mol: 2 mol: 500 mL: 0.03 mol: 1 mol, the amount of hydroquinone is 0.05% of the mass of allyl alcohol, and the mass fraction of sodium hydroxide aqueous solution is 20%.

[0008] Furthermore, the modified epoxy resin is prepared by the following steps: Step B1: Thioglycerol, triethylamine, and anhydrous dichloromethane are mixed and purged with nitrogen. Under nitrogen protection, the mixture is stirred at 150-200 r / min and 0-5℃, and triphenylmethyl chloride is added. The mixture is then heated to 20-25℃ and reacted for 2-3 hours to obtain modified glycerol. Modified glycerol is then mixed with tetrahydrofuran. Under 120-150 r / min and 0℃, sodium hydride is added and stirred for 30-40 minutes. The mixture is then heated to 25-30℃, and 1,3-dichloro-2-propanol is added. The mixture is reacted for 6-8 hours, then cooled to 0℃, and an aqueous solution of sodium hydroxide is added. The mixture is then reacted for 3-5 hours to obtain the modifier. Step B2: Mix the intermediate with anhydrous dichloromethane, purge with nitrogen, stir and add trimethylsilyl iodide at 150-200 r / min and 0℃, and react for 2-3 h to obtain the modifier. Mix dimethylvinylsilyl lithium and tetrahydrofuran, purge with nitrogen, stir and add tetramethylcyclotetrasiloxane at 150-200 r / min and 0℃, heat to 25-30℃, and react for 20-24 h. Then add tetrachlorosilane and continue the reaction for 1-1.5 h to obtain branched polysiloxane. Step B3: Mix branched polysiloxane, modifier, benzophenone and DMF, and react for 20-30 min under conditions of 200-300 r / min, 20-25℃ and 365nm ultraviolet light irradiation to obtain pretreated epoxy resin. Mix pretreated epoxy resin, allyl alcohol, caster catalyst and DMF, purge with nitrogen, and react for 6-8 h under conditions of 200-300 r / min and 40-50℃ to obtain modified epoxy resin.

[0009] Furthermore, in step B1, the molar ratio of thioglycerol, triethylamine, and triphenylmethyl chloride is 1:1:1, the volume ratio of modified glycerol, sodium hydride, 1,3-dichloro-2-propanol, and sodium hydroxide aqueous solution is 1 mmol:2 mmol:2 mmol:15 mL, and the concentration of sodium hydroxide aqueous solution is 2.5 mol / L.

[0010] Furthermore, the molar ratio of the intermediate and trimethylsilyl iodide in step B2 is 1:1.2, and the molar ratio of the Si-Cl bonds on lithium dimethylvinylsilanolate, tetramethylcyclotetrasiloxane, and tetrachlorosilane is 1:3:1.

[0011] Furthermore, in step B3, the molar ratio of branched polysiloxane to modifier is 1:4, the amount of benzophenone is 0.02% of the modifier mass, the molar ratio of Si-H bond on pretreated epoxy resin to allyl alcohol is 1:1, and the amount of caster catalyst is 0.01% of the allyl alcohol mass.

[0012] The beneficial effects of the present invention: The LED lamp bead sleeve prepared by the present invention includes the following raw materials: functionalized resin, modified boron nitride, modified additives, triethylenetetramine and ammonium persulfate. The functionalized resin is prepared by reacting the modified resin with cis-5-dodecenoic acid, thereby esterifying the hydroxyl groups on the modified epoxy resin and the carboxyl groups on cis-5-dodecenoic acid to obtain the functionalized resin.

[0013] Modified epoxy resin is prepared by treating thioglycerol with triphenylmethyl chloride to protect the thiol groups on the thioglycerol, thus obtaining modified glycerol. The modified glycerol reacts with 1,3-dichloro-2-propanol, causing the hydroxyl groups on the modified glycerol to react with a chlorine atom on the 1,3-dichloro-2-propanol, followed by ring closure under the action of sodium hydroxide to form an epoxy group, yielding an intermediate. The intermediate is then deprotected of the thiol groups using trimethylsilyl iodide to obtain a modifier. Dimethylvinylsilyllithium is used as an initiator, and tetramethylcyclotetrasiloxane is used as the polymerization monomer. A polysiloxane with a main chain containing Si-H bonds, a double bond at one end, and lithium silanolate at the other end is formed. Tetrachlorosilane is then added, causing the Si-Cl bonds on the tetrachlorosilane to react with the lithium silanolate, thus obtaining a branched polysiloxane. The branched polysiloxane and a modifier are then reacted under ultraviolet light, causing the double bonds on the branched polysiloxane to react with the thiol groups on the modifier, thus obtaining a pretreated epoxy resin. The pretreated epoxy resin is then reacted with allyl alcohol, causing the Si-H bonds on the pretreated epoxy resin to react with the double bonds on the allyl alcohol, thus obtaining a modified epoxy resin.

[0014] Modified boron nitride is prepared by hydrophilic treatment of hexagonal boron nitride with D-glucose to graft hydroxyl groups onto the surface. The pretreated boron nitride is then treated with methacryloyloxypropyltrimethoxysilane to graft double bonds onto the surface, thus obtaining modified boron nitride.

[0015] The modified additive is prepared by reacting cyanuric chloride with 1,2,2,6,6-pentamethylpiperidinol using temperature control. After the two chlorine atom sites on cyanuric chloride react with the hydroxyl sites on 1,2,2,6,6-pentamethylpiperidinol, allyl alcohol is added to react with the remaining chlorine atom sites on allyl alcohol.

[0016] When the raw materials are mixed and heated, the epoxy groups on the functionalized resin react with triethylenetetramine to form a network structure. Under the action of ammonium persulfate, the double bonds on the side chains of the functionalized resin, the double bonds on the modified boron nitride, and the double bonds on the modified additive undergo free radical polymerization, thereby forming a dense interpenetrating network in the molecular structure. This structure can increase the crosslinking density and raise the glass transition temperature. At the same time, the main chain is a polysiloxane segment, which makes the prepared sleeve have a good high-temperature oxidation resistance. The hindered amine structure on the modified additive can continuously capture and neutralize free radicals that cause thermal oxidation of epoxy resin, thereby significantly delaying embrittlement, yellowing, and decline in mechanical properties. The addition of modified boron nitride can dissipate the heat generated when the LED lamp is working, thereby increasing the service life of the LED lamp. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1: A method for preparing an LED bead sleeve, specifically including the following steps: Step A1: Dissolve D-glucose in deionized water, stir and add hexagonal boron nitride at 200 r / min and 25°C, and stir for 2 h to obtain pretreated boron nitride. Mix the pretreated boron nitride, ethanol and deionized water evenly, stir and add methacryloxypropyltrimethoxysilane at 150 r / min and 75°C, and react for 5 h to obtain modified boron nitride. Step A2: Mix modified epoxy resin, cis-5-dodecenoic acid, hydroquinone and xylene, purge with nitrogen, stir and add p-toluenesulfonic acid pyridine salt under the conditions of 150 r / min and 70℃, and react for 6 h to obtain functionalized resin. Step A3: Mix cyanuric chloride and anhydrous acetone, stir at 200 r / min and 0℃, and add 1,2,2,6,6-pentamethylpiperidinol, sodium hydroxide aqueous solution and tetrabutylammonium bromide. React for 2 h, raise the temperature to 40℃ and continue the reaction for 4 h, raise the temperature to 80℃, add allyl alcohol and hydroquinone, and continue the reaction for 3 h to obtain the modified additive. Step A4: Weigh the following raw materials by weight: 100 parts functionalized resin, 5 parts modified boron nitride, 1 part modified additive, 10 parts triethylenetetramine and 0.1 parts ammonium persulfate. Mix the raw materials evenly and inject them into the mold. After heat treatment at 60°C for 1 hour, raise the temperature to 110°C and heat treatment for 6 hours to obtain LED lamp bead sleeve.

[0019] In step A1, the ratio of D-glucose solution, deionized water, and hexagonal boron nitride is 15g:20mL:3g, and the amount of methacryloyloxypropyltrimethoxysilane is 5% of the mass of the pretreated boron nitride.

[0020] The molar ratio of hydroxyl groups on the modified epoxy resin and cis-5-dodecenoic acid in step A2 is 1:1, the amount of hydroquinone used is 0.05% of the mass of cis-5-dodecenoic acid, and the amount of p-toluenesulfonic acid pyridine salt used is 3% of the mass of cis-5-dodecenoic acid.

[0021] In step A3, the ratio of cyanuric chloride, 1,2,2,6,6-pentamethylpiperidinol, sodium hydroxide aqueous solution, tetrabutylammonium bromide, and allyl alcohol is 1 mol: 2 mol: 500 mL: 0.03 mol: 1 mol, the amount of hydroquinone is 0.05% of the mass of allyl alcohol, and the mass fraction of sodium hydroxide aqueous solution is 20%.

[0022] The modified epoxy resin is prepared by the following steps: Step B1: Thioglycerol, triethylamine, and anhydrous dichloromethane were mixed and purged with nitrogen. Under nitrogen protection, the mixture was stirred at 150 r / min and 0°C, and triphenylmethyl chloride was added. The mixture was then heated to 20°C and reacted for 2 hours to obtain modified glycerol. Modified glycerol was then mixed with tetrahydrofuran. Under nitrogen protection, the mixture was stirred at 120 r / min and 0°C, and sodium hydride was added. The mixture was stirred for 30 minutes, heated to 25°C, and 1,3-dichloro-2-propanol was added. The mixture was reacted for 6 hours, then cooled to 0°C, and an aqueous solution of sodium hydroxide was added. The mixture was reacted for 3 hours to obtain the modifier. Step B2: Mix the intermediate with anhydrous dichloromethane, purge with nitrogen, stir and add trimethylsilyl iodide at 150 r / min and 0 °C, and react for 2 h to obtain the modifier. Mix dimethylvinylsilyl lithium and tetrahydrofuran, purge with nitrogen, stir and add tetramethylcyclotetrasiloxane at 150 r / min and 0 °C, heat to 25 °C and react for 20 h. Then add tetrachlorosilane and continue the reaction for 1 h to obtain branched polysiloxane. Step B3: Branched polysiloxane, modifier, benzophenone and DMF are mixed and reacted for 20 min under the conditions of 200 r / min, 20℃ and 365 nm ultraviolet light irradiation to obtain pretreated epoxy resin. Pretreated epoxy resin, allyl alcohol, caster catalyst and DMF are mixed, nitrogen gas is introduced for protection, and reaction is carried out for 6 h under the conditions of 200 r / min and 40℃ to obtain modified epoxy resin.

[0023] The molar ratio of thioglycerol, triethylamine, and triphenylmethyl chloride in step B1 is 1:1:1, the volume ratio of modified glycerol, sodium hydride, 1,3-dichloro-2-propanol, and sodium hydroxide aqueous solution is 1 mmol:2 mmol:2 mmol:15 mL, and the concentration of sodium hydroxide aqueous solution is 2.5 mol / L.

[0024] The molar ratio of the intermediate and trimethylsilyl iodide mentioned in step B2 is 1:1.2, and the molar ratio of the Si-Cl bonds on lithium dimethylvinylsilanolate, tetramethylcyclotetrasiloxane and tetrachlorosilane is 1:3:1.

[0025] In step B3, the molar ratio of branched polysiloxane to modifier is 1:4, the amount of benzophenone is 0.02% of the modifier mass, the molar ratio of Si-H bond on pretreated epoxy resin to allyl alcohol is 1:1, and the amount of caster catalyst is 0.01% of the allyl alcohol mass.

[0026] Example 2, a method for preparing an LED bead sleeve, specifically includes the following steps: Step A1: Dissolve D-glucose in deionized water, stir and add hexagonal boron nitride at 200 r / min and 30℃, and stir for 2 h to obtain pretreated boron nitride. Mix the pretreated boron nitride, ethanol and deionized water evenly, stir and add methacryloxypropyltrimethoxysilane at 200 r / min and 75℃, and react for 6 h to obtain modified boron nitride. Step A2: Mix modified epoxy resin, cis-5-dodecenoic acid, hydroquinone and xylene, purge with nitrogen, stir and add p-toluenesulfonic acid pyridine salt at a speed of 150 r / min and a temperature of 75°C, and react for 7 h to obtain functionalized resin. Step A3: Mix cyanuric chloride and anhydrous acetone, stir at 200 r / min and 5°C, and add 1,2,2,6,6-pentamethylpiperidinol, sodium hydroxide aqueous solution and tetrabutylammonium bromide. React for 2 h, raise the temperature to 45°C and continue the reaction for 5 h, raise the temperature to 85°C, add allyl alcohol and hydroquinone, and continue the reaction for 4 h to obtain the modified additive. Step A4: Weigh the following raw materials in parts by weight: 110 parts functionalized resin, 8 parts modified boron nitride, 2 parts modified additives, 13 parts triethylenetetramine and 0.2 parts ammonium persulfate. Mix the raw materials evenly and inject them into the mold. After heat treatment at 65°C for 1.3 hours, raise the temperature to 115°C and heat treatment for 7 hours to obtain LED lamp bead sleeves.

[0027] In step A1, the ratio of D-glucose solution, deionized water, and hexagonal boron nitride is 15g:20mL:3g, and the amount of methacryloyloxypropyltrimethoxysilane is 5% of the mass of the pretreated boron nitride.

[0028] The molar ratio of hydroxyl groups on the modified epoxy resin and cis-5-dodecenoic acid in step A2 is 1:1, the amount of hydroquinone used is 0.08% of the mass of cis-5-dodecenoic acid, and the amount of p-toluenesulfonic acid pyridine salt used is 3% of the mass of cis-5-dodecenoic acid.

[0029] In step A3, the ratio of cyanuric chloride, 1,2,2,6,6-pentamethylpiperidinol, sodium hydroxide aqueous solution, tetrabutylammonium bromide, and allyl alcohol is 1 mol: 2 mol: 500 mL: 0.03 mol: 1 mol, the amount of hydroquinone is 0.05% of the mass of allyl alcohol, and the mass fraction of sodium hydroxide aqueous solution is 20%.

[0030] The modified epoxy resin is prepared by the following steps: Step B1: Thioglycerol, triethylamine, and anhydrous dichloromethane were mixed and purged with nitrogen. The mixture was stirred at 150 r / min and 5°C, and triphenylmethyl chloride was added. The mixture was then heated to 20°C and reacted for 3 hours to obtain modified glycerol. Modified glycerol was then mixed with tetrahydrofuran and stirred at 120 r / min and 0°C, and sodium hydride was added. The mixture was stirred for 35 minutes, heated to 30°C, and 1,3-dichloro-2-propanol was added. The mixture was reacted for 7 hours, then cooled to 0°C, and an aqueous sodium hydroxide solution was added. The mixture was reacted for 4 hours to obtain the modifier. Step B2: Mix the intermediate with anhydrous dichloromethane, purge with nitrogen, stir and add trimethylsilyl iodide at 150 r / min and 0°C, and react for 2-3 h to obtain the modifier. Mix lithium dimethylvinylsilane and tetrahydrofuran, purge with nitrogen, stir and add tetramethylcyclotetrasiloxane at 200 r / min and 0°C, raise the temperature to 25°C and react for 24 h. Then add tetrachlorosilane and continue the reaction for 1.3 h to obtain branched polysiloxane. Step B3: Branched polysiloxane, modifier, benzophenone and DMF are mixed and reacted for 25 min at a rotation speed of 200 r / min, a temperature of 25℃ and irradiation with 365 nm ultraviolet light to obtain pretreated epoxy resin. Pretreated epoxy resin, allyl alcohol, caster catalyst and DMF are mixed, nitrogen gas is introduced for protection, and reaction is carried out for 7 h at a rotation speed of 200 r / min and a temperature of 45℃ to obtain modified epoxy resin.

[0031] The molar ratio of thioglycerol, triethylamine, and triphenylmethyl chloride in step B1 is 1:1:1, the volume ratio of modified glycerol, sodium hydride, 1,3-dichloro-2-propanol, and sodium hydroxide aqueous solution is 1 mmol:2 mmol:2 mmol:15 mL, and the concentration of sodium hydroxide aqueous solution is 2.5 mol / L.

[0032] The molar ratio of the intermediate and trimethylsilyl iodide mentioned in step B2 is 1:1.2, and the molar ratio of the Si-Cl bonds on lithium dimethylvinylsilanolate, tetramethylcyclotetrasiloxane and tetrachlorosilane is 1:3:1.

[0033] In step B3, the molar ratio of branched polysiloxane to modifier is 1:4, the amount of benzophenone is 0.02% of the modifier mass, the molar ratio of Si-H bond on pretreated epoxy resin to allyl alcohol is 1:1, and the amount of caster catalyst is 0.01% of the allyl alcohol mass.

[0034] Example 3, a method for preparing an LED lamp bead sleeve, specifically includes the following steps: Step A1: Dissolve D-glucose in deionized water, stir and add hexagonal boron nitride at 300 r / min and 30℃, and stir for 3 h to obtain pretreated boron nitride. Mix the pretreated boron nitride, ethanol and deionized water evenly, stir and add methacryloxypropyltrimethoxysilane at 200 r / min and 80℃, and react for 7 h to obtain modified boron nitride. Step A2: Mix modified epoxy resin, cis-5-dodecenoic acid, hydroquinone and xylene, purge with nitrogen, stir and add p-toluenesulfonic acid pyridine salt at a speed of 200 r / min and a temperature of 80℃, and react for 8 hours to obtain functionalized resin. Step A3: Mix cyanuric chloride and anhydrous acetone, stir at 300 r / min and 5°C, and add 1,2,2,6,6-pentamethylpiperidinol, sodium hydroxide aqueous solution and tetrabutylammonium bromide. React for 3 h, raise the temperature to 50°C and continue the reaction for 6 h, raise the temperature to 90°C, add allyl alcohol and hydroquinone, and continue the reaction for 5 h to obtain the modified additive. Step A4: Weigh the following raw materials in parts by weight: 120 parts functionalized resin, 10 parts modified boron nitride, 3 parts modified additives, 15 parts triethylenetetramine and 0.3 parts ammonium persulfate. Mix the raw materials evenly and inject them into the mold. After heat treatment at 70°C for 1.5 hours, raise the temperature to 120°C and heat treatment for 8 hours to obtain LED lamp bead sleeves.

[0035] In step A1, the ratio of D-glucose solution, deionized water, and hexagonal boron nitride is 15g:20mL:3g, and the amount of methacryloyloxypropyltrimethoxysilane is 5% of the mass of the pretreated boron nitride.

[0036] The molar ratio of hydroxyl groups on the modified epoxy resin and cis-5-dodecenoic acid in step A2 is 1:1, the amount of hydroquinone used is 0.1% of the mass of cis-5-dodecenoic acid, and the amount of p-toluenesulfonic acid pyridine salt used is 3% of the mass of cis-5-dodecenoic acid.

[0037] In step A3, the ratio of cyanuric chloride, 1,2,2,6,6-pentamethylpiperidinol, sodium hydroxide aqueous solution, tetrabutylammonium bromide, and allyl alcohol is 1 mol: 2 mol: 500 mL: 0.03 mol: 1 mol, the amount of hydroquinone is 0.05% of the mass of allyl alcohol, and the mass fraction of sodium hydroxide aqueous solution is 20%.

[0038] The modified epoxy resin is prepared by the following steps: Step B1: Thioglycerol, triethylamine, and anhydrous dichloromethane were mixed and purged with nitrogen. Under nitrogen protection, the mixture was stirred at 200 r / min and 5°C, and triphenylmethyl chloride was added. The mixture was then heated to 25°C and reacted for 3 hours to obtain modified glycerol. Modified glycerol was then mixed with tetrahydrofuran and stirred at 150 r / min and 0°C, and sodium hydride was added. The mixture was stirred for 40 minutes, heated to 30°C, and 1,3-dichloro-2-propanol was added. The mixture was reacted for 8 hours, then cooled to 0°C, and an aqueous solution of sodium hydroxide was added. The mixture was reacted for 5 hours to obtain the modifier. Step B2: Mix the intermediate with anhydrous dichloromethane, purge with nitrogen, stir and add trimethylsilyl iodide at 200 r / min and 0 °C, and react for 3 h to obtain the modifier. Mix dimethylvinylsilane lithium and tetrahydrofuran, purge with nitrogen, stir and add tetramethylcyclotetrasiloxane at 200 r / min and 0 °C, heat to 30 °C and react for 24 h. Then add tetrachlorosilane and continue the reaction for 1.5 h to obtain branched polysiloxane. Step B3: Branched polysiloxane, modifier, benzophenone and DMF are mixed and reacted for 30 min at a rotation speed of 300 r / min, a temperature of 25℃ and irradiation with 365 nm ultraviolet light to obtain pretreated epoxy resin. Pretreated epoxy resin, allyl alcohol, caster catalyst and DMF are mixed, nitrogen gas is introduced for protection, and reaction is carried out for 8 h at a rotation speed of 300 r / min and a temperature of 50℃ to obtain modified epoxy resin.

[0039] The molar ratio of thioglycerol, triethylamine, and triphenylmethyl chloride in step B1 is 1:1:1, the volume ratio of modified glycerol, sodium hydride, 1,3-dichloro-2-propanol, and sodium hydroxide aqueous solution is 1 mmol:2 mmol:2 mmol:15 mL, and the concentration of sodium hydroxide aqueous solution is 2.5 mol / L.

[0040] The molar ratio of the intermediate and trimethylsilyl iodide mentioned in step B2 is 1:1.2, and the molar ratio of the Si-Cl bonds on lithium dimethylvinylsilanolate, tetramethylcyclotetrasiloxane and tetrachlorosilane is 1:3:1.

[0041] In step B3, the molar ratio of branched polysiloxane to modifier is 1:4, the amount of benzophenone is 0.02% of the modifier mass, the molar ratio of Si-H bond on pretreated epoxy resin to allyl alcohol is 1:1, and the amount of caster catalyst is 0.01% of the allyl alcohol mass.

[0042] Comparative Example 1: Compared with Example 1, this comparative example uses hexagonal boron nitride instead of modified boron nitride, while the other steps are the same.

[0043] Comparative Example 2: In this comparative example, dimethyldichlorosilane was used instead of tetrachlorosilane, while the other steps were the same as in Example 1.

[0044] Comparative Example 3: This comparative example uses modified epoxy resin instead of functionalized resin, while the other steps are the same as in Example 1.

[0045] The materials obtained in Examples 1-3 and Comparative Examples 1-3 were placed in a forced-air drying oven according to the standard GB / T 7141-2008, and kept at 150, 180 and 200℃ for 120h respectively. 1A dumbbell-shaped specimens were prepared according to the standard GB / T1040-2018, and tensile strength was tested at a tensile rate of 50mm / min. Notched A-type specimens were prepared according to GB / T1843-2008, and impact strength was tested. The tensile strength retention rate and impact strength retention rate were calculated respectively. The test results are shown in Table 1 below.

[0046] Table 1

[0047] As shown in Table 1, this application has excellent heat aging resistance.

[0048] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing an LED lamp bead sleeve, characterized in that: Specifically, the steps include the following: Step A1: Dissolve D-glucose in deionized water, stir and add hexagonal boron nitride, stir and treat to obtain pretreated boron nitride. Mix pretreated boron nitride, ethanol and deionized water, stir and add methacryloxypropyltrimethoxysilane, react to obtain modified boron nitride. Step A2: Mix modified epoxy resin, cis-5-dodecenoic acid, hydroquinone and xylene, purge with nitrogen, stir and add p-toluenesulfonic acid pyridine salt to react and obtain functionalized resin. Step A3: Mix cyanuric chloride and anhydrous acetone, stir, and add 1,2,2,6,6-pentamethylpiperidinol, sodium hydroxide aqueous solution and tetrabutylammonium bromide to carry out the reaction. Heat the mixture and add allyl alcohol and hydroquinone to continue the reaction to obtain the modified additive. Step A4: Weigh the following raw materials in parts by weight: 100-120 parts of functionalized resin, 5-10 parts of modified boron nitride, 1-3 parts of modified additives, 10-15 parts of triethylenetetramine and 0.1-0.3 parts of ammonium persulfate. Mix the raw materials evenly and inject them into the mold. Heat and keep warm to obtain LED lamp bead sleeves.

2. The method for preparing an LED lamp bead sleeve according to claim 1, characterized in that: In step A1, the ratio of D-glucose solution, deionized water, and hexagonal boron nitride is 15g:20mL:3g, and the amount of methacryloyloxypropyltrimethoxysilane is 5% of the mass of the pretreated boron nitride.

3. The method for preparing an LED lamp bead sleeve according to claim 1, characterized in that: The molar ratio of hydroxyl groups on the modified epoxy resin described in step A2 to cis-5-dodecenoic acid is 1:

1.

4. The method for preparing an LED lamp bead sleeve according to claim 1, characterized in that: The ratio of cyanuric chloride, 1,2,2,6,6-pentamethylpiperidinol, sodium hydroxide aqueous solution, tetrabutylammonium bromide and allyl alcohol used in step A3 is 1 mol: 2 mol: 500 mL: 0.03 mol: 1 mol.

5. The method for preparing an LED lamp bead sleeve according to claim 1, characterized in that: The modified epoxy resin is prepared by the following steps: Step B1: Thioglycerol, triethylamine and anhydrous dichloromethane are mixed, nitrogen gas is introduced for protection, and triphenylmethyl chloride is added while stirring. The mixture is heated to obtain modified glycerol. Modified glycerol and tetrahydrofuran are mixed and stirred, and sodium hydride is added. The mixture is stirred and heated, and 1,3-dichloro-2-propanol is added to react. The mixture is then cooled and an aqueous solution of sodium hydroxide is added to react to obtain the modifier. Step B2: Mix the intermediate with anhydrous dichloromethane, purge with nitrogen, stir and add trimethylsilyl iodide to react and obtain the modifier. Mix dimethylvinylsilyl lithium and tetrahydrofuran, purge with nitrogen, stir and add tetramethylcyclotetrasiloxane, heat and react, then add tetrachlorosilane and continue the reaction to obtain branched polysiloxane. Step B3: The branched polysiloxane, modifier, benzophenone and DMF are mixed and reacted under ultraviolet light to obtain a pretreated epoxy resin. The pretreated epoxy resin, allyl alcohol, castor catalyst and DMF are mixed and reacted under nitrogen protection to obtain a modified epoxy resin.

6. The method for preparing an LED lamp bead sleeve according to claim 5, characterized in that: The molar ratio of thioglycerol, triethylamine and triphenylmethyl chloride in step B1 is 1:1:1, and the volume ratio of modified glycerol, sodium hydride, 1,3-dichloro-2-propanol and sodium hydroxide aqueous solution is 1 mmol:2 mmol:2 mmol:15 mL.

7. The method for preparing an LED lamp bead sleeve according to claim 5, characterized in that: The molar ratio of the intermediate and trimethylsilyl iodide mentioned in step B2 is 1:1.2, and the molar ratio of the Si-Cl bonds on lithium dimethylvinylsilanolate, tetramethylcyclotetrasiloxane and tetrachlorosilane is 1:3:

1.

8. The method for preparing an LED lamp bead sleeve according to claim 5, characterized in that: The molar ratio of branched polysiloxane and modifier in step B3 is 1:4, and the molar ratio of Si-H bonds and allyl alcohol on the pretreated epoxy resin is 1:1.

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