A single-component, yellowing-resistant ultraviolet light delayed curing Mini LED epoxy encapsulation adhesive and preparation method thereof

Abstract

The present invention relates to a single-component, yellowing-resistant ultraviolet light delayed curing Mini LED epoxy encapsulation adhesive and a preparation method thereof, and relates to the field of adhesives. It is composed of the following raw materials: a homemade epoxy silicone oligomer containing a triazine ring structure, a modified epoxy resin, an alicyclic epoxy resin, a reactive diluent, a curing agent, a photobase generator, a photosensitizer, a chain extender, a coupling agent, a defoaming agent, an antioxidant, and a leveling agent. The present invention adds a homemade epoxy silicone oligomer containing a triazine ring structure to the epoxy resin so that the encapsulation adhesive based on the present invention has a higher light transmittance, refractive index, and excellent heat resistance and yellowing resistance. At the same time, the present invention uses a photobase generator as a curing accelerator for an anhydride curing agent. The photobase generator needs to generate an alkaline substance after being irradiated with ultraviolet light, thereby improving the storage stability of the composition, and preparing a single-component Mini LED epoxy encapsulation adhesive.

Description

Technical Field

[0001] The present invention relates to the field of adhesives, and in particular to a single-component, yellowing-resistant ultraviolet light delayed-curing MiniLED epoxy encapsulation adhesive and a preparation method thereof. Background Art

[0002] Mini LED is a new type of LED display technology derived from small-pitch LED. Mini LED generally consists of three parts: Mini LED light-emitting chip, packaging substrate, and optical adhesive layer. The optical adhesive layer encapsulates the surface of the substrate and performs a fixed protection function for the Mini LED light-emitting chip. At present, Mini LED display screens are developing in the direction of large screens, but large-screen Mini LEDs face problems such as difficult packaging and low yield. In addition to requiring the packaging adhesive to have good light transmittance and thermal stability, it is also required to be flat, resistant to yellowing, and airtight.

[0003] Common Mini LED encapsulation adhesives are mainly epoxy resin and silicone resin. Silicone resin has good flexibility, moisture resistance and yellowing resistance, but its mechanical strength is low and its air tightness is poor; epoxy resin has high adhesion, high mechanical strength and corrosion resistance, but epoxy resin still has the following defects: (1) Aromatic epoxy resin contains aromatic rings. After being exposed to ultraviolet light for a long time, the aromatic rings will be oxidized to chromophores such as carbonyl, making the originally transparent epoxy resin dark yellow, affecting the use effect; (2) Alicyclic epoxy resin can better overcome the defects of aromatic aromatic epoxy resin and achieve a certain durability, but the refractive index is generally low and the flexibility is poor; (3) With the use of LED devices, the temperature of the LED chip rises and dissipates heat to the outside world, which in turn causes the temperature of the encapsulation adhesive to rise. As the heating time increases, ordinary epoxy resin encapsulation adhesives show the characteristics of hardening, brittleness and yellowing, which greatly reduces the durability of the material.

[0004] At present, the commonly used Mini LED packaging glue is generally a two-component epoxy glue. Before use, components A and B need to be mixed in a certain proportion and degassed before use. The applicable period after mixing is generally less than 12 hours, and the production efficiency is low. Summary of the invention

[0005] In order to solve the above technical problems, the present invention discloses a single-component, yellowing-resistant UV light delayed curing MiniLED epoxy encapsulant and a preparation method thereof, by providing an epoxy silicone oligomer containing a triazine ring structure and a preparation method thereof, and used for the preparation of a single-component, yellowing-resistant UV light delayed curing Mini LED epoxy encapsulant. The encapsulant of the present invention is a single component, has good storage stability, and the cured product has high light transmittance, refractive index, excellent heat resistance and yellowing resistance, and has a wide range of applications. The present invention discloses a single-component, yellowing-resistant UV light delayed curing MiniLED epoxy encapsulant, characterized in that it comprises the following raw materials in parts by weight:

[0006] 10-25 parts of self-made epoxy silicone oligomer containing triazine ring structure; 5-10 parts of modified epoxy resin; 5-10 parts of alicyclic epoxy resin; 3-8 parts of active diluent; 20-45 parts of curing agent; 1-10 parts of photobase generator; 0.1-3 parts of photosensitizer; 0.5-5 parts of chain extender; 0.5-2 parts of coupling agent; 0.1-2 parts of defoamer; 0.1-2 parts of antioxidant; 0.1-2 parts of leveling agent;

[0007] The epoxy silicone oligomer containing a triazine ring structure has a structure of the following formula I:

[0008]

[0009] Formula I

[0010] Wherein R1 in Formula I is , n=1~8.

[0011] Furthermore, the epoxy silicone oligomer containing a triazine ring structure is prepared according to the following steps:

[0012] In a reaction vessel flask equipped with a N2 device and a reflux condenser, add a total of 120 g of 1,2-epoxy-4-vinylcyclohexane and a triazine ring structure-containing silicone oligomer to 40-60 g of toluene solvent, slowly heat to 65-80°C, add 0.01-0.02 g of chloroplatinic acid isopropanol solution, and stir at a speed of 500-800 r / min for 3-5 hours under N2 protection. Test the epoxy equivalent at intervals. Stop stirring when the epoxy equivalent tends to be constant, and evaporate the solvent under vacuum to obtain a colorless transparent liquid, which is the epoxy silicone oligomer containing a triazine ring structure.

[0013] Furthermore, the mass fraction of chloroplatinic acid in the isopropanol solution is 1 to 3%.

[0014] Furthermore, the 1,2-epoxy-4-vinylcyclohexane has a structure of Formula II, and the organosilicon oligomer containing a triazine ring structure has a structure of Formula III.

[0015]

[0016] Formula II

[0017]

[0018] Formula III

[0019] Among them, R2 is .

[0020] Furthermore, the organosilicon oligomer containing a triazine ring structure is prepared according to the following steps:

[0021] Weigh 100g of triallyl isocyanurate, put it into a reaction vessel flask equipped with a N2 device and a reflux condenser, add 40-60g of toluene solvent, slowly heat up to 65-80°C, add 0.01-0.02g of chloroplatinic acid isopropanol solution, and under N2 protection, gradually add 20-30g of hydrogen-terminated polydimethylsiloxane dropwise during mechanical stirring, maintain the temperature at 65-80°C, stir at a speed of 500-800r / min for 3-5h, stop stirring when the system temperature drops to 30°C, evacuate the solvent under reduced pressure to obtain a transparent viscous liquid, which is a silicone oligomer containing a triazine ring structure.

[0022] Furthermore, the hydrogen-terminated polydimethylsiloxane has a structure as shown in Formula IV.

[0023]

[0024] Formula IV

[0025] Furthermore, the epoxy silicone oligomer containing a triazine ring structure has a light transmittance of 92% to 95% and a refractive index of 1.56 to 1.58.

[0026] Furthermore, the epoxy silicone oligomer containing a triazine ring structure has an epoxy equivalent of 200 g / eq to 400 g / eq.

[0027] The modified epoxy resin is one of silicone modified epoxy resin, polyurethane modified epoxy resin, dimer acid modified epoxy resin, hydrogenated bisphenol A epoxy resin, nano core-shell rubber modified epoxy resin, nano silicon dioxide modified epoxy resin or a mixture of any of them.

[0028] The alicyclic epoxy resin is one of 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexyl methyl ester, bis((3,4-epoxycyclohexyl)methyl)adipate, vinylcyclohexene dioxide, 3,4-epoxycyclohexyl methyl methacrylate, (3,4,3',4'-diepoxy)bicyclohexane, cyclohexane-1,2-dicarboxylic acid diglycidyl ester, or a mixture of any of them.

[0029] The active diluent is one of 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, phenyl glycidyl ether, propylene glycol diglycidyl ether, C12-C14 fatty glycidyl ether, or a mixture of any of the above.

[0030] The curing agent may be one of methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride and tetrahydrophthalic anhydride, or a mixture of any of them.

[0031] The photobase generator can generate organic bases such as biguanide, diethylamine, guanidine, imidazole and other alkaline substances after being irradiated with ultraviolet light, which can promote the curing reaction of the anhydride curing agent and the epoxy resin. It can be one of 2-(3-benzoylphenyl)propionic acid 1,2-diisopropyl-3-[di(dimethylamino)methylene]guanidine salt, 9-anthracene methyl ester N,N-diethylcarbamate, 2-(3-benzoylphenyl)propionic acid guanidine salt, 1-(anthraquinone-2-yl)imidazolecarboxylic acid ethyl ester, (Z)-{[bis(dimethylamino)methylene]amino}-N-cyclohexyl(cyclohexylamino)methaneiminetetra(3-fluorophenyl)borate and 1,2-dicyclohexyl-4,4,5,5-tetramethylbisguanidinebutyltriphenylborate or a mixture of any of them.

[0032] The photosensitizer can promote the decomposition and generation of base by the photobase generator under ultraviolet light, and can be one of 2-isopropylthioxanthone, 9,10-diethoxyanthracene, 9,10-dibutoxyanthracene, or a mixture of any of them.

[0033] The chain extender is one of ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, glycerol, trimethylolpropane, polyether diol or polyether triol with a molecular weight of 500-2000, or a mixture of any of the above.

[0034] The coupling agent is one of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane and γ-(2,3-epoxypropyloxy)propyltrimethoxysilane or a mixture of any of the above.

[0035] The defoamer is a silicone type defoamer, preferably one of BYK-310, BYK-348, BYK-A530, BYK-054, BYK-1794, R-6501, Airex922, Airex944, and Airex900, or a mixture of any of them.

[0036] The antioxidant is one of 2,6-di-tert-butyl-p-cresol, pentaerythritol tetrakis[B-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, octadecyl B-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, triphenyl phosphite, trioctyl phosphite or a mixture of any of them.

[0037] The leveling agent is one of polysiloxane, polyether modified, acrylate, and silicone, or a mixture of any of the above.

[0038] The present invention also discloses a method for preparing the above-mentioned single-component, yellowing-resistant ultraviolet light delayed curing Mini LED epoxy encapsulant, which is prepared by the following steps:

[0039] 10-25 parts of homemade epoxy silicone oligomer containing triazine ring structure, 5-10 parts of modified epoxy resin, 5-10 parts of alicyclic epoxy resin, 3-8 parts of active diluent, 1-10 parts of photobase generator, 0.1-3 parts of photosensitizer and 0.1-2 parts of antioxidant are added into a stirring kettle, and the mixture is rotated at 30-50 r / min and stirred for 60 minutes at a temperature of 80-120°C and in a vacuum and light-proof state until the solid is dissolved; 20-45 parts of curing agent, 0.5-5 parts of chain extender, 0.5-2 parts of coupling agent, 0.1-2 parts of defoaming agent and 0.1-2 parts of leveling agent are added, and the mixture is rotated at 30-50 r / min and rotated at 300-800 r / min in a vacuum and light-proof state, and stirred for 30 minutes to obtain a single-component, yellowing-resistant UV delayed-curing Mini LED epoxy encapsulant.

[0040] The beneficial effects of the present invention include:

[0041] (1) The present invention uses a two-step copolymerization modification method to modify triallyl isocyanurate containing a triazine ring structure with silicone and epoxy to prepare an alicyclic epoxy resin containing a triazine ring structure and a long silicone chain.

[0042] (2) The present invention improves the light transmittance and refractive index of the encapsulant by adding an epoxy silicone oligomer containing a triazine ring structure with high light transmittance and high refractive index to the encapsulant. At the same time, the long silicone chain in the polymer improves the flexibility and moisture resistance of the cured product; the triazine ring structure improves the heat resistance of the cured product; and the alicyclic epoxy functional group improves the long-term yellowing resistance of the cured product.

[0043] (3) The present invention uses a photobase generator instead of a conventional anhydride curing accelerator. The photobase generator generates an organic base after being irradiated with ultraviolet light, which further triggers the curing reaction of the anhydride curing agent and the epoxy resin. A single-component min LED encapsulation adhesive with good storage stability is prepared. The adhesive is simple and convenient to use and is expected to improve production line efficiency. DETAILED DESCRIPTION

[0044] In order to make the technical solution of the present invention clearer, the technical solution of the present invention is described clearly and completely. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] 25 parts of self-made epoxy silicone oligomer containing triazine ring structure, 8 parts of nano core-shell rubber modified epoxy resin, 8 parts of 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexyl methyl ester, 5 parts of 1,4-butanediol diglycidyl ether, 8 parts of (Z)-{[bis(dimethylamino)methylene]amino}-N-cyclohexyl(cyclohexylamino)methaneiminetetrakis(3-fluorophenyl)borate, 0.5 parts of 2-isopropylthioxanthone and 0.5 parts of 2,6-di-tert-butyl-p-cresol were added to a stirring kettle, and the mixture was rotated at 30 r / min at a temperature of 110°C and in a vacuum state to avoid light. The mixture was stirred for 60 minutes until the solid dissolved. 38 parts of methylhexahydrophthalic anhydride, 1 part of 1,4-butanediol, 0.5 parts of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 0.2 parts of BYK-310, and 0.2 parts of BYK-353 were added. The mixture was rotated at 800 r / min and in a vacuum state to avoid light. The mixture was stirred for 30 minutes to obtain a single-component, yellowing-resistant, UV-delayed-curing Mini LED epoxy encapsulant.

[0047] The self-made epoxy silicone oligomer containing a triazine ring structure is prepared according to the following steps:

[0048] In a reaction vessel flask equipped with a N2 device and a reflux condenser, add a total of 120 g of 1,2-epoxy-4-vinylcyclohexane and a triazine ring structure-containing silicone oligomer to 60 g of toluene solvent, slowly heat to 80°C, add 0.01 g of chloroplatinic acid isopropanol solution, and stir at a speed of 800 r / min for 5 h under N2 protection. Test the epoxy equivalent at intervals. Stop stirring when the epoxy equivalent tends to be constant, and evaporate the solvent under vacuum to obtain a colorless transparent liquid, which is the epoxy silicone oligomer containing a triazine ring structure.

[0049] The mass fraction of chloroplatinic acid in the isopropanol solution is 2%.

[0050] The organosilicon oligomer containing a triazine ring structure is prepared according to the following steps:

[0051] Weigh 100g of triallyl isocyanurate, put it into a reaction vessel flask equipped with a N2 device and a reflux condenser, add 60g of toluene solvent, slowly heat up to 65°C, add 0.01 of chloroplatinic acid isopropanol solution, and under N2 protection, gradually add 20g of hydrogen-terminated polydimethylsiloxane dropwise during mechanical stirring, maintain the temperature at 65°C, stir at a speed of 800r / min for 5h, stop stirring when the system temperature drops to 30°C, evacuate the solvent under reduced pressure to obtain a transparent viscous liquid, which is a silicone oligomer containing a triazine ring structure.

[0052] Example 2

[0053] 20 parts of self-made epoxy silicone oligomer containing triazine ring structure, 6 parts of nano-silica modified epoxy resin, 10 parts of bis((3,4-epoxycyclohexyl)methyl) adipate, 5 parts of ethylene glycol diglycidyl ether, 6 parts of 1,2-dicyclohexyl-4,4,5,5-tetramethylbisguanidine butyl triphenyl borate, 0.4 parts of 9,10-diethoxyanthracene and 0.5 parts of triphenyl phosphite were added into a stirred tank, and the mixture was stirred for 60 minutes at a temperature of 110°C and in a vacuum state. Then, 35 parts of methyltetrahydrophthalic anhydride, 1 part of neopentyl glycol, 0.5 parts of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 0.2 parts of BYK-348 and 0.2 parts of BYK-333 were added into the stirred tank, and the mixture was stirred for 60 minutes at a temperature of 110°C and in a vacuum state. r / min, stirring for 30 minutes can obtain a single-component, yellowing-resistant UV-delayed curing Mini LED epoxy encapsulation adhesive.

[0054] The self-made epoxy silicone oligomer containing a triazine ring structure is prepared according to the following steps:

[0055] In a reaction vessel flask equipped with a N2 device and a reflux condenser, 120 g of 1,2-epoxy-4-vinylcyclohexane and a triazine ring structure-containing organosilicon oligomer were added to 50 g of toluene solvent, and the temperature was slowly raised to 70°C. 0.015 g of chloroplatinic acid isopropanol solution was added. Under N2 protection, the mixture was stirred at a speed of 600 r / min for 4 h. The epoxy equivalent was tested at intervals. When the epoxy equivalent tended to be constant, the stirring was stopped, and the solvent was evaporated under vacuum to obtain a colorless transparent liquid, which was the epoxy organosilicon oligomer containing a triazine ring structure.

[0056] The mass fraction of chloroplatinic acid in the isopropanol solution is 2.5%.

[0057] The organosilicon oligomer containing a triazine ring structure is prepared according to the following steps:

[0058] Weigh 100g of triallyl isocyanurate, put it into a reaction vessel flask equipped with a N2 device and a reflux condenser, add 50g of toluene solvent, slowly heat to 70°C, add 0.02g of chloroplatinic acid isopropanol solution, and under N2 protection, gradually add 25g of hydrogen-terminated polydimethylsiloxane dropwise during mechanical stirring, maintain the temperature at 70°C, stir at a speed of 600r / min for 4h, stop stirring when the system temperature drops to 30°C, evacuate the solvent under reduced pressure to obtain a transparent viscous liquid, which is a silicone oligomer containing a triazine ring structure.

[0059] Example 3

[0060] 18 parts of self-made epoxy silicone oligomer containing triazine ring structure, 10 parts of hydrogenated bisphenol A epoxy resin, 10 parts of vinyl cyclohexene dioxide, 8 parts of propylene glycol diglycidyl ether, 8 parts of 2-(3-benzoylphenyl) propionic acid 1,2-diisopropyl-3-[di(dimethylamino)methylene]guanidine salt, 0.5 parts of 9,10-dibutoxyanthracene and 0.5 parts of trioctyl phosphite were added to a stirring kettle, and the mixture was stirred for 60 minutes at a temperature of 120°C and in a vacuum state until the solid was dissolved. 40 parts of methylhexahydrophthalic anhydride, 0.5 parts of diethylene glycol, 0.5 parts of γ-(2,3-epoxypropyloxy)propyltrimethoxysilane, 0.2 parts of Airex922 and 0.2 parts of BYK-323 were added, and the mixture was stirred for 60 minutes at a temperature of 120°C and in a vacuum state until the solid was dissolved. r / min, stirring for 30 minutes can obtain a single-component, yellowing-resistant UV-delayed curing MiniLED epoxy encapsulation adhesive.

[0061] The self-made epoxy silicone oligomer containing a triazine ring structure is prepared according to the following steps:

[0062] In a reaction vessel flask equipped with a N2 device and a reflux condenser, add a total of 120 g of 1,2-epoxy-4-vinylcyclohexane and a triazine ring structure-containing silicone oligomer to 50 g of toluene solvent, slowly heat to 75°C, add 0.015 g of chloroplatinic acid isopropanol solution, and stir at a speed of 700 r / min for 4 hours under N2 protection. Test the epoxy equivalent at intervals. Stop stirring when the epoxy equivalent tends to be constant, and evaporate the solvent under vacuum to obtain a colorless transparent liquid, which is the epoxy silicone oligomer containing a triazine ring structure.

[0063] The mass fraction of chloroplatinic acid in the isopropanol solution is 2.5%.

[0064] The organosilicon oligomer containing a triazine ring structure is prepared according to the following steps:

[0065] Weigh 100g of triallyl isocyanurate, put it into a reaction vessel flask equipped with a N2 device and a reflux condenser, add 50g of toluene solvent, slowly heat to 70°C, add 0.02g of chloroplatinic acid isopropanol solution, and under N2 protection, gradually add 25g of hydrogen-terminated polydimethylsiloxane dropwise during mechanical stirring, maintain the temperature at 70°C, stir at a speed of 700r / min for 4.5h, stop stirring when the system temperature drops to 30°C, evacuate the solvent under reduced pressure to obtain a transparent viscous liquid, which is a silicone oligomer containing a triazine ring structure.

[0066] Example 4

[0067] 22 parts of self-made epoxy silicone oligomer containing triazine ring structure, 8 parts of silicone modified epoxy resin, 10 parts of 3,4-epoxycyclohexylmethyl methacrylate, 5 parts of 1,4-butanediol diglycidyl ether, 9 parts of 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidine butyl triphenyl borate, 0.8 parts of 2-isopropylthioxanthone and 0.5 parts of 2,6-di-tert-butyl-p-cresol were added to a stirred tank, and the mixture was stirred for 60 minutes at a temperature of 110°C and in a vacuum state. Then, 36 parts of methyltetrahydrophthalic anhydride, 0.5 parts of propylene glycol, 0.8 parts of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 0.2 parts of Airex944 and 0.2 parts of BYK-310 were added, and the mixture was stirred for 60 minutes at a temperature of 110°C and in a vacuum state. r / min, stirring for 30 minutes can obtain a single-component, yellowing-resistant UV-delayed curing Mini LED epoxy encapsulation adhesive.

[0068] The self-made epoxy silicone oligomer containing a triazine ring structure is prepared according to the following steps:

[0069] In a reaction vessel flask equipped with a N2 device and a reflux condenser, 120 g of 1,2-epoxy-4-vinylcyclohexane and a triazine ring structure-containing organosilicon oligomer were added to 40 g of toluene solvent, and the temperature was slowly raised to 80°C. 0.02 g of chloroplatinic acid isopropanol solution was added. Under N2 protection, the mixture was stirred at a speed of 800 r / min for 3 h. The epoxy equivalent was tested at intervals. When the epoxy equivalent tended to be constant, the stirring was stopped, and the solvent was evaporated under vacuum to obtain a colorless transparent liquid, which was the epoxy organosilicon oligomer containing a triazine ring structure.

[0070] The mass fraction of chloroplatinic acid in the isopropanol solution is 1.5%.

[0071] The organosilicon oligomer containing a triazine ring structure is prepared according to the following steps:

[0072] Weigh 100g of triallyl isocyanurate, put it into a reaction vessel flask equipped with a N2 device and a reflux condenser, add 60g of toluene solvent, slowly raise the temperature to 75°C, add 0.02g of chloroplatinic acid isopropanol solution, and under the protection of N2, gradually add 30g of hydrogen-terminated polydimethylsiloxane dropwise during mechanical stirring, maintain the temperature at 70°C, stir at a speed of 600r / min for 4h, stop stirring when the system temperature drops to 30°C, evacuate the solvent under reduced pressure to obtain a transparent viscous liquid, which is a silicone oligomer containing a triazine ring structure.

[0073] Comparative Example 1

[0074] 33 parts of nano core-shell rubber modified epoxy resin, 8 parts of 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexyl methyl ester, 5 parts of 1,4-butanediol diglycidyl ether and 0.5 parts of 2,6-di-tert-butyl-p-cresol were added to a stirred kettle, and the mixture was rotated at 30 r / min and stirred for 60 min at a temperature of 110°C and in a vacuum and light-proof state until the solid was dissolved; 38 parts of methyl hexahydrophthalic anhydride, 0.5 parts of methyl tributylphosphine dimethyl phosphate, 1 part of 1,4-butanediol, 0.5 parts of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 0.2 parts of BYK-310 and 0.2 parts of BYK-353 were added, and the mixture was rotated at 30 r / min and 800 r / min in a vacuum and light-proof state, and stirred for 30 min to obtain the adhesive of Comparative Example 1.

[0075] Comparative Example 2

[0076] 26 parts of nano-silica modified epoxy resin, 10 parts of bis((3,4-epoxycyclohexyl)methyl)adipate, 5 parts of ethylene glycol diglycidyl ether and 0.5 parts of triphenyl phosphite were added to a stirring kettle, and the mixture was stirred for 60 minutes at a temperature of 110°C and in a vacuum and light-proof state at a revolution of 40 r / min until the solid was dissolved; 35 parts of methyltetrahydrophthalic anhydride, 1 part of neopentyl glycol, 0.3 parts of triphenylphosphine, 0.2 parts of BYK-348 and 0.2 parts of BYK-333 were added, and the mixture was stirred for 30 minutes at a revolution of 40 r / min and a rotation of 600 r / min in a vacuum and light-proof state to obtain the adhesive of Comparative Example 2.

[0077] Test methods and experimental results:

[0078] 1. Materials and methods

[0079] 1.1 Experimental testing:

[0080] Transmittance test: Use UV756CRT ultraviolet-visible spectrophotometer with a scanning range of 300-800nm, a resolution of 1nm, a thickness of the cured sample of 2mm, and take the 450nm value.

[0081] Refractive index test: Use WYA Abbe refractometer, test temperature: (25±5)℃. Drop the uncured sample directly on the prism of the Abbe refractometer for test.

[0082] Hardness test: LX-A and LX-D Shore hardness testers were used, and the test temperature was (25±5)°C. The thickness of the cured sample was 1 cm.

[0083] Thermal aging test: The cured samples were placed in an oven for thermal aging test to observe the changes in transmittance and color of the cured samples after thermal aging at 200°C for 500 hours.

[0084] UV aging test: Place the cured sample under a UV lamp for a UV aging test, and observe the changes in transmittance and color of the cured sample after 500 hours of UV aging.

[0085] Red ink test: After curing, the sample was boiled in red ink at 100℃ for 12h and the state after boiling was observed.

[0086] Elastic modulus and glass transition temperature (Tg) testing instrument: DMA.

[0087] Glue curing conditions: LED 365nm 500mw / cm 2 ×10S+130℃@1h+150℃@2h.

[0088] 1.2 Test materials: Comparative Examples 1 to 2, Examples 1 to 4.

[0089]

[0090] Except for the experimental treatment, other operations were the same in this experiment.

[0091] 2. Results and Analysis:

[0092] in conclusion

[0093] Compared with the transmittance and refractive index data of Comparative Examples 1 and 2 in the table, the transmittance and refractive index of the present invention are significantly higher than those of Comparative Examples 1 and 2, and the present invention has higher transparency and better LED light display effect. Compared with the glass transition temperature (Tg) data of Comparative Examples 1 and 2 in the table, the Tg of the present invention is significantly improved, showing better heat resistance than the comparative example. Compared with the hardness and elastic modulus data of Comparative Examples 1 and 2 in the table, the hardness and elastic modulus of the present invention are lower, showing better flexibility than the comparative example. Compared with the heat aging resistance, UV resistance and red ink test results of Comparative Examples 1 and 2 in the table, the present invention shows better heat resistance, yellowing resistance and other aging resistance than the comparative example. Compared with the viscosity change data of Comparative Examples 1 and 2 in the table and the present invention for 7 days, the present invention shows better storage stability. It can be seen that the adhesive of the present invention is a single-component epoxy adhesive suitable for Mini LED packaging.

[0094] The above description is only a preferred implementation example of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are within the protection scope of the present invention.

Claims

1. A single-component, yellowing-resistant UV-delayed curing Mini LED epoxy encapsulant, characterized in that: The invention comprises the following raw materials in parts by weight: 10 to 25 parts of self-made epoxy silicone oligomer containing triazine ring structure; 5-10 parts of modified epoxy resin; 5-10 parts of alicyclic epoxy resin; 3 to 8 parts of active diluent; 20-45 parts of curing agent; 1 to 10 parts of photobase generator; Photosensitizer 0.1-3 parts; Chain extender 0.5-5 parts; 0.5-2 parts of coupling agent; Defoaming agent 0.1-2 parts; 0.1-2 parts of antioxidant; 0.1-2 parts of leveling agent; The self-made epoxy silicone oligomer containing a triazine ring structure has the following structure of Formula I: Formula I Wherein R1 in Formula I is , n=1~8.

2. A single-component, yellowing-resistant UV-delayed curing Mini LED epoxy encapsulant according to claim 1, characterized in that: The epoxy silicone oligomer containing a triazine ring structure is prepared according to the following steps: In a reaction vessel flask equipped with a N2 device and a reflux condenser, add 120 g of 1,2-epoxy-4-vinylcyclohexane and a triazine ring structure-containing organosilicon oligomer to 40-60 g of toluene solvent, slowly heat to 65-80°C, add 0.01-0.02 g of chloroplatinic acid isopropanol solution, stir at a speed of 500-800 r / min for 3-5 hours under N2 protection, test the epoxy equivalent at intervals, stop stirring when the epoxy equivalent tends to be constant, and evaporate the solvent under vacuum to obtain a colorless transparent liquid, which is the epoxy organosilicon oligomer containing a triazine ring structure; The mass fraction of chloroplatinic acid in the isopropanol solution is 1 to 3%; The 1,2-epoxy-4-vinylcyclohexane has a structure of Formula II, and the organosilicon oligomer containing a triazine ring structure has a structure of Formula III. Formula II Formula III Among them, R2 is , where n=1~8; The organosilicon oligomer containing a triazine ring structure is prepared according to the following steps: Weigh 100g of triallyl isocyanurate, put it into a reaction vessel flask equipped with a N2 device and a reflux condenser, add 40-60g of toluene solvent, slowly heat to 65-80°C, add 0.01-0.02g of chloroplatinic acid isopropanol solution, and under N2 protection, gradually dropwise add 20-30g of hydrogen-terminated polydimethylsiloxane during mechanical stirring, maintain the temperature at 65-80°C, stir at a speed of 500-800r / min for 3-5h, stop stirring when the system temperature drops to 30°C, evacuate and reduce pressure to remove the solvent to obtain a transparent viscous liquid, which is an organosilicon oligomer containing a triazine ring structure; The hydrogen-terminated polydimethylsiloxane has a structure as shown in Formula IV; , where n=1~8 Formula IV.

3. A single-component, yellowing-resistant UV-delayed curing Mini LED epoxy encapsulant according to claim 2, characterized in that: The epoxy silicone oligomer containing a triazine ring structure has a light transmittance of 92% to 95% and a refractive index of 1.56 to 1.

58.

4. A single-component, yellowing-resistant UV-delayed curing Mini LED epoxy encapsulant according to claim 2, characterized in that: The epoxy organosilicon oligomer containing a triazine ring structure has an epoxy equivalent of 200 g / eq to 400 g / eq.

5. A single-component, yellowing-resistant UV-delayed curing Mini LED epoxy encapsulant according to claim 1, characterized in that: The curing agent is one of methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride and tetrahydrophthalic anhydride, or a mixture of any of them.

6. A single-component, yellowing-resistant UV-delayed curing Mini LED epoxy encapsulant according to claim 1, characterized in that: The photobase generator is selected from 2-(3-benzoylphenyl)propionic acid 1,2-diisopropyl-3-[di(dimethylamino)methylene]guanidine salt, 9-anthracene methyl ester N,N-diethylcarbamate, 2-(3-benzoylphenyl)propionic acid guanidine salt, 1-(anthraquinone-2-yl)imidazolecarboxylic acid ethyl ester, (Z)-{[bis(dimethylamino)methylene]amino}-N-cyclohexyl(cyclohexylamino)methaneiminetetrakis(3-fluorophenyl)borate and 1,2-dicyclohexyl-4,4,5,5-tetramethylbisguanidinebutyltriphenylborate or a mixture of any of them.

7. The one-component, yellowing-resistant UV-delayed curing Mini LED epoxy encapsulant according to claim 1, characterized in that: The photosensitizer is selected from one of 2-isopropylthioxanthone, 9,10-diethoxyanthracene, 9,10-dibutoxyanthracene or a mixture of any of them.

8. The method for preparing the single-component, yellowing-resistant UV-delayed curing Mini LED epoxy encapsulant according to any one of claims 1 to 7, characterized in that Prepared by the following steps: 10-25 parts of homemade epoxy silicone oligomer containing triazine ring structure, 5-10 parts of modified epoxy resin, 5-10 parts of alicyclic epoxy resin, 3-8 parts of active diluent, 1-10 parts of photobase generator, 0.1-3 parts of photosensitizer and 0.1-2 parts of antioxidant are added into a stirring kettle, and the mixture is rotated at 30-50 r / min and stirred for 60 minutes at a temperature of 80-120°C and in a vacuum and light-proof state until the solid is dissolved; 20-45 parts of curing agent, 0.5-5 parts of chain extender, 0.5-2 parts of coupling agent, 0.1-2 parts of defoaming agent and 0.1-2 parts of leveling agent are added, and the mixture is rotated at 30-50 r / min and 300-800 r / min in a vacuum and light-proof state, and stirred for 30 minutes to obtain a single-component, yellowing-resistant UV delayed-curing Mini LED epoxy encapsulant.

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