Composite particle and preparation method thereof, and LED packaging body preparation method

Abstract

The invention provides a composite particle and a preparation method thereof, and a preparation method of an LED packaging body. The composite particle comprises a core and a shell, the core comprises a cross-linked product of a stimuli-responsive monomer and a vinyl monomer and an antioxidant, and the antioxidant is dispersed in the cross-linked product; the shell comprises polyacrylate, and the thickness of the shell is 1-10 nm; the cross-linked product can be isomerized or cracked when irradiated at the wavelength of 200-400 nm. The composite particles can be well preserved before being used. When the antioxidant composite particle is used, the antioxidant composite particle can be isomerized or cracked when irradiated under the wavelength of 200-400 nm, and the thin shell of the antioxidant composite particle collapses accordingly, so that the antioxidant is exposed, and other substances jointly used with the antioxidant composite particle are protected; when being used together with silica gel glue, the antioxidant is prevented from being in contact with a metal catalyst in the silica gel glue in advance to cause failure.

Description

Technical Field

[0001] The present disclosure relates to the technical field of composite particles, and in particular to a composite particle and a preparation method thereof, and a method for preparing an LED package. Background Art

[0002] Quantum dots have excellent optical properties and are hailed as one of the most promising technologies in the display industry. However, from the perspective of materials, the instability of quantum dots in water and oxygen hinders their application in practical processes. In recent years, the stability of quantum dots has been improved by adding antioxidants or encapsulating barrier layers on the surface of quantum dots. Summary of the invention

[0003] The purpose of the present disclosure is to provide a composite particle and a preparation method thereof, and a method for preparing an LED package, so as to solve the problem in the prior art that antioxidants deactivate metal catalysts in silicone glue.

[0004] According to the first aspect of the present disclosure, a composite particle is provided, which includes a core and a shell, the core includes a cross-linked product of a stimuli-responsive monomer and a vinyl monomer, and an antioxidant, and the antioxidant is dispersed in the cross-linked product; the shell includes a polyacrylate, and the thickness of the shell is 1~10 nm; the cross-linked product can be isomerized or broken when irradiated at a wavelength of 200~400 nm.

[0005] Optionally, the stimuli-responsive monomer includes one of azobenzene, o-nitrobenzyl ester, a disulfide bond, and a vinyl group, or the stimuli-responsive monomer contains a boron-substituted dipyrromethene structure and a vinyl group.

[0006] Optionally, the vinyl monomer is selected from at least one of the group consisting of methyl methacrylate, styrene, octadecyl methacrylate, cyclohexyl methacrylate, n-butyl methacrylate, isobornyl methacrylate, methyl acrylate, lauryl methacrylate, ethyl acrylate, vinyl acetate, butyl acrylate, and isooctyl acrylate.

[0007] Optionally, the antioxidant includes one or more of hindered phenols, hindered amines, phosphites, thioesters or thioethers.

[0008] Preferably, the antioxidant is selected from hindered phenol antioxidant 1010, hindered amine antioxidant DNP or phosphite antioxidant 168.

[0009] Optionally, the mass fraction of the antioxidant in the composite particles is 0.1-20%.

[0010] Optionally, the molecular weight of the cross-linked product is 10,000-5,000,000.

[0011] According to a second aspect of the present disclosure, a method for preparing any of the above-mentioned composite particles is provided, wherein the composite particles are prepared by an emulsion method.

[0012] Optionally, water, a first emulsifier, a first vinyl monomer, a stabilizer, a stimulus-responsive monomer and an antioxidant are mixed in a container and pre-emulsified to obtain a first emulsion; water, a second emulsifier and a second vinyl monomer are mixed and pre-emulsified to obtain a second emulsion; an initiator is added to the first emulsion, heated to react for a first time, and then the second emulsion is added to the container in multiple times, and the heating reaction ends for a second time; an organic alcohol is added to the container to demulsify, and after separation and purification, low-temperature vacuum drying is performed to obtain composite particles.

[0013] Optionally, the mass of the second vinyl monomer is 5% to 30% of the mass of the first vinyl monomer.

[0014] According to the third aspect of the present disclosure, a method for preparing an LED package is provided, wherein any of the above-mentioned composite particles, quantum dots and silicone glue are mixed and arranged on an LED chip, and then the silicone glue is cured at high temperature to obtain an intermediate LED package, and the intermediate LED package is irradiated under 200~400nm light for a certain period of time to cause the cores of the composite particles to isomerize or rupture, exposing the antioxidant, thereby obtaining an LED package.

[0015] By applying the above technical solution, the above composite particles can be kept intact before being used. When they are used, light irradiation at a wavelength of 200 to 400 nm may cause isomerization or rupture, and the thin shell collapses accordingly, exposing the antioxidant, thereby protecting other substances used together with the composite particles. In particular, the composite particles can be used together with quantum dots to achieve protection of the quantum dots. When it comes into contact with silicone glue, the antioxidant is not exposed, thereby avoiding the deactivation effect of the antioxidant on the metal catalyst required for the curing of the silicone glue. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting part of the present application are used to provide a further understanding of the present disclosure. The exemplary embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure. In the drawings:

[0017] Figure 1 A schematic diagram of the structure of a composite particle according to an embodiment of the present disclosure.

[0018] Figure 2 Schematic diagram of the structural changes of a composite particle under stimulus response conditions according to an embodiment of the present disclosure.

[0019] Figure 3 Graphs showing brightness attenuation changes of quantum dot LED packages of some embodiments and comparative examples of the present disclosure.

[0020] Reference numerals: 1: core; 11: cross-linked product; 12: antioxidant; 2: shell. DETAILED DESCRIPTION

[0021] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0022] According to the first aspect of the present disclosure, a composite particle is provided, which includes a core and a shell, the core includes a cross-linked product of a stimuli-responsive monomer and a vinyl monomer, and an antioxidant, and the antioxidant is dispersed in the cross-linked product; the shell includes a polyacrylate, and the thickness of the shell is 1~10 nm; the cross-linked product can be isomerized or broken when irradiated at a wavelength of 200~400 nm.

[0023] The composite particles can be kept intact before being used. When they are used, they can be isomerized (isomerization makes the gaps between polymer molecules larger, and the antioxidant can flow out of the gaps) or broken when irradiated at a wavelength of 200-400nm, and their thin shells will collapse, exposing the antioxidant, thereby protecting other substances used with the composite particles. In particular, the composite particles can be used together with quantum dots to protect the quantum dots. When in contact with silicone glue, the antioxidant is not exposed, avoiding the deactivation effect of the antioxidant on the metal catalyst.

[0024] In some embodiments, the core has a size of 90-990 nm or 100-900 nm.

[0025] In some embodiments, the stimulus-responsive monomer is selected from functional groups including azobenzene, o-nitrobenzyl ester, disulfide bonds, and vinyl groups, or the stimulus-responsive monomer comprises a boron-substituted dipyrromethene structure and a vinyl group. The azobenzene group is based on isomerization, and the o-nitrobenzyl ester, disulfide bond group, and boron dipyrromethene structure are based on rupture.

[0026] In some embodiments, the vinyl monomer is selected from at least one of the group consisting of methyl methacrylate, styrene, octadecyl methacrylate, cyclohexyl methacrylate, n-butyl methacrylate, isobornyl methacrylate, methyl acrylate, lauryl methacrylate, ethyl acrylate, vinyl acetate, butyl acrylate, and isooctyl acrylate.

[0027] The antioxidant includes P, S or N elements. In some embodiments, the antioxidant includes one or more of hindered phenols, hindered amines, phosphites, thioesters or thioethers. Hindered phenols can be thiophenols, triazine hindered phenols, isocyanate hindered phenols, etc. Hindered amines can be naphthylamine, diphenylamine, p-diphenylamine, quinoline derivatives, etc. In some preferred embodiments, the antioxidant is selected from hindered phenol antioxidant 1010, hindered amine antioxidant DNP or phosphite antioxidant 168.

[0028] In some embodiments, the mass fraction of the antioxidant in the composite particles is 0.1-20%, preferably 5%-10%.

[0029] In some embodiments, the molecular weight of the cross-linked product is 10,000-5,000,000, preferably 50,000-500,000.

[0030] In some embodiments, the size of the composite particles is 10-1000 nanometers or 100-1000 nanometers. In some embodiments, the shape of the composite particles is spherical.

[0031] According to a second aspect of the present disclosure, a method for preparing any of the above-mentioned composite particles is provided, wherein the composite particles are prepared by an emulsion method.

[0032] In some embodiments, water, a first emulsifier, a first vinyl monomer, a stabilizer, a stimulus-responsive monomer, and an antioxidant are mixed in a container and pre-emulsified to obtain a first emulsion; water, a second emulsifier, and a second vinyl monomer are mixed and pre-emulsified to obtain a second emulsion; an initiator is added to the first emulsion, heated to react for a first time, and then the second emulsion is added to the container in multiple times, and the heating reaction ends for a second time; an organic alcohol is added to the container to demulsify, and after separation and purification, low-temperature vacuum drying is performed to obtain composite particles.

[0033] In some embodiments, water and a first emulsifier are stirred at a stirring speed of 100-1000 rpm for T1 time, and then a first vinyl monomer, a stabilizer, a stimulus-responsive monomer, and an antioxidant are added and stirred for T2 time to obtain a first emulsion, wherein T1 or T2 is 1-120 minutes.

[0034] The first vinyl monomer and the second vinyl monomer are the same or different. In some embodiments, the organic alcohol is ethanol.

[0035] In some embodiments, the emulsifier is selected from at least one of anionic emulsifiers, cationic emulsifiers, amphoteric emulsifiers, and nonionic emulsifiers.

[0036] In some embodiments, the mass of water is 100% to 1000% of the mass of the first vinyl monomer, the mass of the first emulsifier is 0.1% to 20% of the mass of water, the mass of the stabilizer is 0.01% to 1% of the mass of the first vinyl monomer, the mass of the stimuli-responsive monomer is 0.5% to 10% of the mass of the first vinyl monomer, and the mass of the antioxidant is 0.05% to 15% of the mass of the first vinyl monomer.

[0037] In some embodiments, the stabilizer is a long-chain fatty alcohol or a long-chain alkane, and the number of carbon atoms is not less than 16. In some embodiments, the number of carbon atoms of the stabilizer is less than or equal to 22. In some embodiments, the stabilizer is n-hexadecane.

[0038] In some embodiments, the temperature of the first heating reaction time is selected from 20°C to 95°C, and the reaction time is 2h to 12h.

[0039] In some embodiments, the second emulsion is added using a feeder, and the addition time is controlled to be completed within 5 to 120 minutes.

[0040] In some embodiments, the temperature of the second heating reaction time is selected from 20° C. to 95° C., and the reaction time is 0.5 h to 24 h.

[0041] In some embodiments, the mass of the second vinyl monomer is 5% to 30% of the mass of the first vinyl monomer, thereby further ensuring that the shell polymer can cover the core, avoiding direct contact between the antioxidant and the silicone glue, and preventing the antioxidant from being too thick to be exposed.

[0042] In some embodiments, the conditions for low-temperature vacuum drying are a temperature selected from 20°C to 80°C, a vacuum time of 0.5h to 12h, and a vacuum degree of less than -0.01MPa.

[0043] In some embodiments, the product after low-temperature vacuum drying is subjected to a pulverization treatment, such as grinding, to prepare composite particles of small size.

[0044] According to the third aspect of the present disclosure, a method for preparing an LED package is provided, wherein the above-mentioned composite particles, quantum dots and silicone glue are mixed and arranged on an LED chip, and then the silicone glue is cured at high temperature to obtain an intermediate LED package, and the intermediate LED package is irradiated under 200~400nm light for a certain period of time to cause the cores of the composite particles to isomerize or rupture, exposing the antioxidant to obtain an LED package.

[0045] The above preparation method avoids direct contact between the antioxidant and the silicone glue of the encapsulation glue, preventing the metal catalyst in the silicone glue from being poisoned. Since the thin shell of the composite particle has no cross-linked monomer, the shell will collapse and deform after the internal structure of the core changes or breaks, and the exposed antioxidant can protect the quantum dots.

[0046] In some embodiments, the irradiation intensity is 0-800 mw / cm 2 The irradiation time is 5min~120min.

[0047] Hereinafter, the embodiments are described in more detail with reference to specific examples. However, they are illustrative examples of the present disclosure, and the present disclosure is not limited thereto.

[0048] Example 1

[0049] Weigh 0.8 g of sodium dodecylbenzene sulfonate and dissolve it in 100 g of water. Stir at 500 rpm for 30 min to obtain an emulsifier aqueous solution. Weigh 9 g of methyl methacrylate, 9 g of styrene, 0.02 g of n-hexadecane, 1.2 g of bisacryloylcystamine (containing disulfide bonds) and hindered phenol antioxidant 1010 in sequence, dissolve them in each other, add them to the emulsifier aqueous solution, and continue stirring for 30 min to obtain the first emulsion.

[0050] 0.06 g of sodium dodecylbenzene sulfonate was weighed and dissolved in 7 g of water, and stirred at 500 rpm for 30 min to obtain an emulsifier aqueous solution. 0.6 g of butyl acrylate and 0.6 g of styrene were weighed and added to the emulsifier aqueous solution, and the stirring was continued for 30 min to obtain a second emulsion.

[0051] Weigh 0.5 g potassium persulfate and add it to the first emulsion; after nitrogen deoxygenation, react at 70°C, 500 rpm and nitrogen protection for 4 hours. Inject the second emulsion into the first emulsion at a rate of 0.27 mL / min and continue to react for 4 hours.

[0052] After the reaction was completed, 10 g of ethanol was added to break the emulsion, and the mixture was centrifuged at 8000 rpm for 10 min to obtain a precipitate, which was vacuum dried at 70°C for 12 h, taken out and ground into powder to obtain powdery composite particles.

[0053] Weigh 80 parts by mass of thermosetting methyl-phenyl silicone resin, 40 ppm of Karstedt catalyst (platinum catalyst), 19 parts by mass of quantum dot powder and 1 part of functional particle powder, mix them evenly, and place them in a vacuum stirring and degassing machine. Degas them under vacuum stirring at an orbital speed of 600 rpm and a rotational speed of 500 rpm for 5 min to 10 min to obtain a mixed glue.

[0054] The mixed glue was poured into the packaging cavity of the LED bracket using a glue dispenser, and the LED bracket was placed in an oven and baked at 150 °C for 2 h.

[0055] After curing, the LED chip is heated to 200mW / cm 2The chip was irradiated under a 365 nm UV lamp for 30 minutes, and then taken out and placed in an oven at 65°C and RH95% for aging. The chip was taken out at regular intervals and its optical performance was tested with an integrating sphere. The first test point was taken as 100%, and the brightness data measured after aging was divided by the first test point to obtain the brightness percentage. Generally, the brightness attenuation is observed when LEDs age, which basically corresponds to the decrease in quantum dot efficiency.

[0056] Example 2

[0057] 0.8 g of sodium dodecylbenzene sulfonate was weighed and dissolved in 100 g of water, and stirred at 500 rpm for 30 min to obtain an emulsifier aqueous solution. 9 g of methyl methacrylate, 9 g of styrene, 0.02 g of n-hexadecane, 1.2 g of ((diazene-1,2-diylbis(4,1-phenylene))bis(oxy))bis(propane-3,1-diyl)bis(2-methyl acrylate) and hindered phenol antioxidant 1010 were weighed in sequence, dissolved in each other, added to the emulsifier aqueous solution, and stirred for 30 min to obtain the first emulsion.

[0058] 0.06 g of sodium dodecylbenzene sulfonate was weighed and dissolved in 7 g of water, and stirred at 500 rpm for 30 min to obtain an emulsifier aqueous solution. 0.6 g of butyl acrylate and 0.6 g of styrene were weighed and added to the emulsifier aqueous solution, and the stirring was continued for 30 min to obtain a second emulsion.

[0059] Weigh 0.5 g potassium persulfate and add it to the first emulsion; after nitrogen deoxygenation, react at 70°C, 500 rpm and nitrogen protection for 4 hours. Inject the second emulsion into the first emulsion at a rate of 0.27 mL / min and continue to react for 4 hours.

[0060] After the reaction was completed, 10 g of ethanol was added to break the emulsion, and the mixture was centrifuged at 8000 rpm for 10 min to obtain a precipitate, which was vacuum dried at 70°C for 12 h, taken out and ground into powder to obtain powdery composite particles.

[0061] Weigh 80 parts by mass of thermosetting methyl-phenyl silicone resin, 40 ppm of Karstedt catalyst (platinum catalyst), 19 parts by mass of quantum dot powder and 1 part of functional particle powder, mix them evenly, and place them in a vacuum stirring and degassing machine. Degas them under vacuum stirring at an orbital speed of 600 rpm and a rotational speed of 500 rpm for 5 min to 10 min to obtain a mixed glue.

[0062] The mixed glue was poured into the packaging cavity of the LED bracket using a glue dispenser, and the LED bracket was placed in an oven and baked at 150 °C for 2 h.

[0063] After curing, the LED chip is heated to 200mW / cm 2The chips were irradiated under a 365 nm UV lamp for 30 min, and then taken out and placed in an oven at 65 °C and RH95% for aging. The chips were taken out at regular intervals and their optical properties were tested using an integrating sphere.

[0064] Comparative Example 1

[0065] The preparation of powdered composite particles is the same as in Example 1.

[0066] 80 parts by mass of thermosetting methyl-phenyl silicone resin, 19 parts by mass of quantum dot powder and 1 part of powdered composite particles were weighed and uniformly mixed, and then placed in a vacuum stirring and degassing machine. Vacuum stirring and degassing were performed for 5 min to 10 min at an orbital speed of 600 rpm and a rotation speed of 500 rpm to obtain a mixed glue.

[0067] The mixed glue was poured into the packaging cavity of the LED bracket using a glue dispenser, and the LED bracket was placed in an oven and baked at 150 °C for 2 h.

[0068] After curing, the chips were taken out and placed in an oven at 65°C and RH95% for aging. The chips were taken out at regular intervals and their optical properties were tested using an integrating sphere.

[0069] Comparative Example 2

[0070] 80 parts by mass of thermosetting methyl-phenyl silicone resin, 40 ppm of Karstedt catalyst (platinum catalyst), 19 parts by mass of quantum dot powder and 1 part of hindered phenol antioxidant 1010 were weighed and evenly mixed, then placed in a vacuum stirring degassing machine, and vacuum stirred and degassed for 5 min to 10 min at an orbital speed of 600 rpm and an autorotational speed of 500 rpm to obtain a mixed glue.

[0071] The mixed glue was poured into the packaging cavity of the LED bracket using a glue dispenser, and the LED bracket was placed in an oven and baked at 150 °C for 2 h.

[0072] After curing, the chips were taken out and placed in an oven at 65°C and RH95% for aging. The chips were taken out at regular intervals and their optical properties were tested using an integrating sphere.

[0073] Comparative Example 3

[0074] Weigh 80 parts by mass of thermosetting methyl-phenyl silicone resin, 40 ppm of Karstedt catalyst (platinum catalyst) and 20 parts by mass of hindered phenol antioxidant 1010, mix them evenly and place them in a vacuum stirring degassing machine. Degas them under vacuum stirring at an orbital speed of 600 rpm and an autorotational speed of 500 rpm for 5 min to 10 min to obtain a mixed glue.

[0075] The mixed glue was poured into the packaging cavity of the LED bracket using a glue dispenser, and the LED bracket was placed in an oven and baked at 150 °C for 2 h.

[0076] After curing, the LED chip is heated to 200mW / cm 2 The chips were irradiated under a 365 nm UV lamp for 30 min, and then taken out and placed in an oven at 65 °C and RH95% for aging. The chips were taken out at regular intervals and their optical properties were tested using an integrating sphere.

[0077] The aging test results of each embodiment and comparative example are shown in Figure 3 .Depend on Figure 3 From the analysis of the test results, it can be seen that the LED chip prepared by the method of Example 1 has good stability, and its brightness decay is maintained within 5% after aging for 1000 hours, which means that after ultraviolet response stimulation, the composite particles of the powder release antioxidants, which can well maintain the stability of the quantum dots. The composite particles prepared by the method of Example 2 represent that the structure of the composite particles isomerizes after ultraviolet response stimulation, and the antioxidant is partially exposed, which protects the quantum dots to a certain extent. Therefore, the brightness decay of its LED chip after aging for 1000 hours is maintained at 7.5%. However, the antioxidant of Comparative Example 1 cannot be released without ultraviolet stimulation, and its performance is close to that of Comparative Example 3 without adding antioxidants. Comparative Example 2 directly adds antioxidants to the formula, which causes the silicone resin to be unable to solidify and loses its oxygen and water barrier capabilities, and performs the worst.

[0078] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A composite particle, characterized in that: The composite particles include a core and a shell, wherein the core includes a cross-linked product of a stimuli-responsive monomer and a vinyl monomer, and an antioxidant, wherein the antioxidant is dispersed in the cross-linked product; the shell includes polyacrylate, and the thickness of the shell is 1 to 10 nm; and the cross-linked product can be isomerized or broken when irradiated at a wavelength of 200 to 400 nm.

2. The composite particle according to claim 1, characterized in that The stimulus-responsive monomer includes one of azobenzene, o-nitrobenzyl ester, disulfide bond and vinyl group, or the stimulus-responsive monomer contains a boron-substituted dipyrromethene structure and vinyl group.

3. The composite particle according to claim 1, characterized in that The vinyl monomer is at least one selected from the group consisting of methyl methacrylate, styrene, octadecyl methacrylate, cyclohexyl methacrylate, n-butyl methacrylate, isobornyl methacrylate, methyl acrylate, lauryl methacrylate, ethyl acrylate, vinyl acetate, butyl acrylate, and isooctyl acrylate.

4. The composite particle according to claim 1, characterized in that The antioxidant includes one or more of hindered phenols, hindered amines, phosphites, thioesters or thioethers; preferably, the antioxidant is selected from hindered phenol antioxidant 1010, hindered amine antioxidant DNP or phosphite antioxidant 168.

5. The composite particle according to claim 1, characterized in that The mass fraction of the antioxidant in the composite particles is 0.1-20%.

6. The composite particle according to claim 1, characterized in that The molecular weight of the cross-linked product is 10,000-5,000,000.

7. A method for preparing composite particles according to any one of claims 1 to 6, characterized in that: The composite particles are prepared by an emulsion method.

8. The method for preparing composite particles according to claim 7, characterized in that: Water, a first emulsifier, a first vinyl monomer, a stabilizer, the stimulus-responsive monomer and the antioxidant are mixed in a container and pre-emulsified to obtain a first emulsion; water, a second emulsifier and a second vinyl monomer are mixed and pre-emulsified to obtain a second emulsion; an initiator is added to the first emulsion, heated to react for a first time, and then the second emulsion is added to the container in multiple times, and the heating reaction ends for a second time; an organic alcohol is added to the container to break the emulsion, and after separation and purification, low-temperature vacuum drying is performed to obtain the composite particles.

9. The method for preparing composite particles according to claim 8, characterized in that: The mass of the second vinyl monomer is 5% to 30% of the mass of the first vinyl monomer.

10. A method for preparing an LED package, characterized in that: The composite particles, quantum dots and silicone glue as described in any one of claims 1 to 6 are mixed and arranged on an LED chip, and then the silicone glue is cured at high temperature to obtain an intermediate LED package. The intermediate LED package is irradiated under 200-400nm light for a certain period of time to isomerize or rupture the cores of the composite particles and expose the antioxidant to obtain the LED package.

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