TWI762315B - A kind of preparation method of modified quantum dot and quantum dot masterbatch - Google Patents

Abstract

90%；通過與改性劑相互作用，提高了量子點在高分子母粒中的分散性，解決了量子點在高溫製程中量子產率下降的問題；本發明還公開了一種量子點母粒之製備方法，將改性量子點製成母粒，技術簡單，擴大了量子點的應用範圍。 The invention discloses a preparation method of modified quantum dots. The preparation raw materials include: quantum dots and modifier; the weight ratio of the quantum dots to the modifier is 1:(2-20); Quantum Yield Maintenance Rate of Dots

90%; by interacting with the modifier, the dispersibility of the quantum dots in the polymer master batch is improved, and the problem of the quantum yield drop of the quantum dots in the high temperature process is solved; the invention also discloses a quantum dot master batch In the preparation method, the modified quantum dots are made into master batches, the technology is simple, and the application range of the quantum dots is expanded.

Description

A kind of preparation method of modified quantum dot and quantum dot masterbatch

The invention relates to the technical field of quantum dots, in particular to a method for preparing modified quantum dots and quantum dot master batches.

Quantum dots are nanoscale semiconductors. By applying a certain electric field or light pressure to the nanosemiconductor material, they will emit light of a specific frequency, due to the properties of this nanosemiconductor that confine electrons and electron holes. , similar to atoms or molecules in nature, so they are called quantum dots. Quantum dots are added to polymer materials and further made into profiles, which can be used in backlight and lighting industries.

The quantum dot diffuser used in the backlight module is mainly produced by extrusion molding, and the polymer masterbatch and quantum dots are mixed and extruded to obtain a plate. There are the following difficulties to be overcome in the process of quantum dot diffusion plate, one is how to uniformly disperse the quantum dots in the polymer masterbatch, and the other is that the quantum yield of quantum dots will decrease during the high temperature granulation or extrusion process.

90%；所述改性劑為重均分子量為5,000~100,000的丙烯酸聚合物；所述丙烯酸聚合物的聚合單體選自甲基丙烯酸甲酯、甲基丙烯酸、甲基丙烯酸月桂酯、丙烯酸甲酯、丙烯酸、丙烯酸 丁酯、丙烯酸甲酯、丙烯酸乙酯、丙烯酸異辛酯、甲基丙烯酸乙酯、甲基丙烯酸丁酯中的一種或多種的混合。 In order to solve the above problems, the first aspect of the present invention provides a method for preparing modified quantum dots, the preparation raw materials include: quantum dots and modifier; the weight ratio of the quantum dots to the modifier is 1:(2 ~20); quantum yield maintenance rate of the modified quantum dots

90%; the modifier is an acrylic polymer with a weight average molecular weight of 5,000-100,000; the polymerized monomer of the acrylic polymer is selected from methyl methacrylate, methacrylic acid, lauryl methacrylate, methyl acrylate , a mixture of one or more of acrylic acid, butyl acrylate, methyl acrylate, ethyl acrylate, isooctyl acrylate, ethyl methacrylate, and butyl methacrylate.

As a preferred technical solution, the quantum dots are ternary alloy materials composed of three kinds of Cd, Zn, Se, S, In, and P and/or four kinds of Cd, Zn, Se, S, In, and P. A quaternary alloy material with various compositions.

The second aspect of the present invention provides a method for preparing the modified quantum dots as described above, comprising the following steps: dissolving the quantum dots and the modifier in a benign solvent, mixing the two solutions, and after the reaction is completed, the mixed solution is Add in poor solvent, precipitate out, remove the solvent, dry the precipitate, and pulverize it.

As a preferred technical solution, the weight ratio of the quantum dots to the benign solvent for dissolving the quantum dots is 1:(4~5); the concentration of the modifier dissolved in the benign solvent is 20~40wt%.

The third-party manufacturer of the present invention provides a method for preparing quantum dot masterbatch.

As a preferred technical solution, the resin is selected from allyl diethylene glycol dicarbonate, polymethyl methacrylate, polystyrene, polycarbonate, poly-4-methyl-1-pentene, styrene- A mixture of one or more of acrylonitrile copolymer, polymethyl methacrylate-styrene copolymer, and cycloolefin polymer.

As a preferred technical solution, the aromatic compound is selected from 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-tris Azine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid, β- (3 , 5-di-tert-butyl-4-hydroxyphenyl) propionate isooctyl ester, β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl ester, 1,3, 5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tetrakis[beta-(3,5-di-tert-butyl-4-hydroxyphenyl) ) propionate] pentaerythritol ester, tris [2,4-di-tert-butylphenyl] phosphite in one or more mixtures.

The fourth aspect of the present invention provides a method for preparing quantum dot masterbatches as described above, comprising the following steps: mixing modified quantum dots, aromatic compounds and resins, extruding and granulating, and the process temperature is 150-250° C. .

Beneficial effects: The present invention provides a method for preparing modified quantum dots. By interacting with modifiers, the dispersibility of quantum dots in polymer master batches is improved, and the quantum yield decline of quantum dots in high temperature process is solved. The present invention also provides a preparation method of quantum dot master batch, the modified quantum dot is made into master batch, the technology is simple, and the application range of quantum dot is expanded.

Figure 1 is a schematic diagram of the action mechanism of the modifier of the present invention.

FIG. 2 is a technical schematic diagram of Embodiment 3 of the present invention.

FIG. 3 is a sample diagram of Example 3 of the present invention.

The content of the present invention can be further understood in conjunction with the following detailed description of the preferred embodiments of the present invention and the included examples. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. To the extent that definitions of specific terms disclosed in the prior art are inconsistent with any definitions provided in this application, the definitions of terms provided in this application shall control.

As used herein, features in the singular and plural are not intended to include features in the plural unless the context clearly dictates otherwise. It is also to be understood that the term "prepared from" as used herein is synonymous with "comprising" and that "comprising", "including", "having", "comprising" and/or "comprising" when used in this specification used to mean the stated compositions, steps, methods, article or device, but does not preclude the presence or addition of one or more other compositions, steps, methods, articles or devices. Furthermore, the use of "preferred," "preferably," "more preferred," etc. when describing embodiments of the present application refers to embodiments of the invention that, under certain circumstances, may provide certain benefits. However, other embodiments may also be preferred, under the same or other circumstances. In addition, the recitation of one or more preferred embodiments does not imply that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of the present invention.

The term "quantum yield" as used herein refers to the utilization rate of light quantum in a photochemical reaction. Specifically, the quantum yield of a photochemical reaction can be defined as the number of molecules of reactant produced per absorption of one quantum, which is usually is for a specific wavelength, that is, quantum yield = (number of molecules generated product) / (quantum number of absorbed).

The term "quantum yield maintenance" herein refers to the percentage of the quantum yield of the quantum dots after modification or processing to the quantum yield of the quantum dots before modification or processing.

90%；所述改性劑為重均分子量為5,000~100,000的丙烯酸聚合物；所述丙烯酸聚合物的聚合單體選自甲基丙烯酸甲酯、甲基丙烯酸、甲基丙烯酸月桂酯、丙烯酸甲酯、丙烯酸、丙烯酸丁酯、丙烯酸甲酯、丙烯酸乙酯、丙烯酸異辛酯、甲基丙烯酸乙酯、甲基丙烯酸丁酯中的一種或多種的混合。 In order to solve the above problems, the first aspect of the present invention provides a method for preparing modified quantum dots, the preparation raw materials include: quantum dots and modifier; the weight ratio of the quantum dots to the modifier is 1:(2 ~20); quantum yield maintenance rate of the modified quantum dots

90%; the modifier is an acrylic polymer with a weight average molecular weight of 5,000-100,000; the polymerized monomer of the acrylic polymer is selected from methyl methacrylate, methacrylic acid, lauryl methacrylate, methyl acrylate , a mixture of one or more of acrylic acid, butyl acrylate, methyl acrylate, ethyl acrylate, isooctyl acrylate, ethyl methacrylate, and butyl methacrylate.

In some preferred embodiments, the weight ratio of the quantum dots to the modifier is 1:(2.2~18); further preferably, the weight ratio of the quantum dots to the modifier is 1:(2.4~16 ); further, the weight ratio of the quantum dots to the modifier is 1:(3~12).

In some preferred embodiments, the quantum dots are ternary alloy materials composed of three of Cd, Zn, Se, S, In, P and/or composed of Cd, Zn, Se, S, In, P four made up of four Element alloy material; further preferably, the quantum dots are selected from a mixture of one or more of CdZnSeS, CdZnSe, CdZnS, and InZnP.

10nm。 In some preferred embodiments, the particle size of the quantum dots

10nm.

The quantum dots in the present invention can be commercially available, and the preparation methods of quantum dots in the art can be divided into three categories: chemical solution growth method, epitaxial growth method, and electric field confinement method. The inventors found that the quantum dots prepared by the chemical solution growth method have better effect. Quantum dots with narrower diameter distribution can improve the stability of quantum yield. In addition, the inventor also found that the use of ternary or quaternary alloy materials with specific particle sizes as quantum dots makes quantum dots have excellent optical properties and quantum yield, and the heat resistance is improved. The reason is that the ternary, The structure of the quaternary alloy material has a gradient, and its defect state has an impact on the heat resistance. With the particle size larger than 10nm, the heat resistance of the material is further improved, and the heat recovery is enhanced, and it is more suitable for making masterbatches, diffusion plates, etc.

In some preferred embodiments, the modifier is an acrylic polymer with a weight average molecular weight of 8,000-80,000; further preferably, the modifier is an acrylic polymer with a weight average molecular weight of 10,000-70,000.

In some preferred embodiments, the polymerized monomer of the acrylic polymer is selected from one or more of methyl methacrylate, methacrylic acid, lauryl methacrylate, methyl acrylate, acrylic acid, and butyl acrylate Mixing; further preferably, the polymerized monomer of the acrylic polymer is selected from a mixture of one or more of methyl methacrylate, methacrylic acid, lauryl methacrylate, and methyl acrylate.

In some preferred embodiments, the modifier is selected from methyl methacrylate-lauryl methacrylate-methacrylic acid copolymer (P(MMA-co-LMA-co-MAA), weight average molecular weight Mw ~36000, monomer mole composition 49.4%, 44.4%, 6.2%)), methyl methacrylate-methacrylic acid copolymer (P(MMA-co-MAA), weight average molecular weight Mw~34000, monomer mole composition ratio 1: 0.016) of one a mixture of one or more.

The preparation method of the copolymer in the present invention can be any one well known to those skilled in the art, such as emulsion polymerization, solution polymerization, suspension polymerization and the like.

In the research, the inventor found that the surface properties of quantum dots can be changed by using appropriate modifiers. The functional groups in the structure are exchanged with the ligands on the surface of the quantum dots and are firmly bonded to the quantum dots. On the one hand, the main chain is connected with the solvent. Or the resin substrate is compatible, on the other hand, it forms a three-dimensional barrier around the quantum dots, avoids the aggregation of quantum dots, improves the dispersibility of quantum dots, and the modifier can precipitate with quantum dots in poor solvents, improving the modification of quantum dots. yield and performance without affecting the optical properties of quantum dots. Figure 1 is a schematic diagram of the action mechanism of the modifier of the present invention.

The second aspect of the present invention provides a method for preparing the modified quantum dots as described above, comprising the following steps: dissolving the quantum dots and the modifier in a benign solvent, mixing the two solutions, and after the reaction is completed, the mixed solution is Add in poor solvent, precipitate out, remove the solvent, dry the precipitate, and pulverize it.

In some preferred embodiments, the weight ratio of the quantum dots to the benign solvent for dissolving the quantum dots is 1:(4~5); the concentration of the modifier dissolved in the benign solvent is 20~40wt%.

In some preferred embodiments, the benign solvent is selected from a mixture of one or more of toluene, ethanol, ether, acetone, acetic acid, and chloroform; further preferably, the benign solvent is toluene.

In some preferred embodiments, the poor solvent is selected from a mixture of one or more of n-hexane, n-octane, and cyclohexane; further preferably, the poor solvent is n-hexane.

In some preferred embodiments, the weight ratio of the quantum dots to the modifier solution is 1:(4.5~15); further preferably, the weight ratio of the quantum dots to the modifier solution is 1:(5 ~12).

In some preferred embodiments, the weight ratio of the quantum dots to the poor solvent is 1:(40~70); further preferably, the weight ratio of the quantum dots to the poor solvent is 1:(50~68); Further, the weight ratio of the quantum dots to the poor solvent is 1:(55~65).

In some preferred embodiments, the preparation method of the modified quantum dots includes the following steps: weighing 20-40 grams of quantum dots, adding 100-150 grams of toluene, stirring and heating to 40-60° C., adding 300-380 grams of The modifier toluene solution (concentration is 20~40wt%) is dropped into the quantum dot solution, and after being incubated for 1~5 days, it is cooled to room temperature; the above mixed solution is added to 1,000~2,000 grams of n-hexane, precipitated out, and the solvent is removed , 40 ~ 60 ℃ vacuum drying precipitation, pulverized until the powder size reaches the micron level or millimeter level, that is, it is obtained.

In some preferred embodiments, the yield of the method for preparing modified quantum dots is not less than 88%.

The third-party manufacturer of the present invention provides a quantum dot masterbatch, and the preparation raw materials include: 1-5wt% of the modified quantum dots described above, 0.5-20wt% of an aromatic compound, and the remainder is resin.

In some preferred embodiments, the resin is selected from the group consisting of allyl diethylene glycol dicarbonate, polymethyl methacrylate, polystyrene, polycarbonate, poly-4-methyl-1-pentene, styrene - a mixture of one or more of acrylonitrile copolymer, polymethyl methacrylate-styrene copolymer, and cycloolefin polymer; further preferably, the resin is selected from polymethyl methacrylate (PMMA), polymethyl methacrylate (PMMA), A mixture of one or more of styrene (PS) and polycarbonate (PC).

The modified quantum dots in the present invention are used to prepare optical materials. Compared with traditional inorganic optical materials, optical polymer materials have the advantages of low density, impact resistance, low cost, easy processing and the like, and have been widely used in recent years. In the present invention, polymethyl methacrylate (PMMA), polystyrene (PS), and polycarbonate (PC) may be commercially available raw materials.

In some preferred embodiments, the aromatic compound is selected from 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5- Triazine-2,4,6-(1H,3H,5H)-trione (CAS No.: 40601-76-1), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyl) Benzyl) isocyanuric acid (CAS number: 27676-62-6), β- (3,5-di-tert-butyl-4-hydroxyphenyl) isooctyl propionate (CAS number: 125643-61-0 ), β- (3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate (CAS number: 2082-79-3), 1,3,5-trimethyl-2,4 ,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (CAS No.: 1709-70-2), tetrakis[β-(3,5-di-tert-butyl-4-hydroxybenzene) one or more of tris[2,4-di-tert-butylphenyl]phosphite (CAS number: 31570-04-4) mix.

The inventor found in the research that the introduction of aromatic compounds into the quantum dot masterbatch can improve the quantum yield drop problem of the masterbatch in the process. The energy free radicals are converted into low-energy aromatic free radicals, which inhibit the destructive oxidation reaction from continuing. The conjugated structure in the benzene ring can also absorb ultraviolet rays, avoiding the deterioration of quantum dots and the discoloration and yellowing of masterbatches. Elements such as sulfur and phosphorus can be introduced, so that the oxidative free radicals generated at high temperature are rapidly destroyed. When choosing an aromatic compound, it should be noted that the type that does not affect the optical properties of the product before and after heating.

The fourth aspect of the present invention provides a method for preparing quantum dot masterbatches as described above, comprising the following steps: mixing modified quantum dots, aromatic compounds and resins, extruding and granulating, and the process temperature is 150-250° C. .

In some preferred embodiments, the preparation method of the quantum dot masterbatch includes the following steps: mixing the modified quantum dots and the aromatic compound, and then mixing with the resin uniformly, adding the extruder to the feed funnel, and the feeding temperature It is 200~240℃, the discharge temperature is 180~220℃, water-cooled, diced, and dried.

Example

The technical solutions of the present invention will be described in detail below through the examples, but the protection scope of the present invention is not limited to the examples. The raw materials used in this application are commercially available unless otherwise specified.

Example 1

Embodiment 1 provides a kind of preparation method of modified quantum dots, and its preparation method is as follows: Description: Weigh 30g of quantum dots in a 1L conical flask, add 120g of toluene, stir and heat to 50°C, drop 360g of modifier toluene solution (with a concentration of 33.33wt%) into the above-mentioned conical flask, keep warm for 2 days , cooled to room temperature; added the above mixed solution to 1,600g of n-hexane, precipitated out, removed the solvent, dried the precipitation in a vacuum at 50°C, and pulverized until the powder size reached the millimeter level to obtain 135g of modified quantum dots with a yield of >99 %.

The quantum dots are CdZnSeS. In this example, green CdZnSeS (particle size 12 nm) and red CdZnSeS (particle size 14 nm) are modified respectively; the modifier is PMMA-LMA-MAA copolymer, and the weight average molecular weight is 36000.

A small amount of unmodified quantum dots and modified quantum dot samples were dissolved in toluene, and their quantum yield (QY), emission wavelength (λ) and half-peak width (FWHM) were measured. The results are shown in Table 1. The QY quantity test results found that the QY of the modified green CdZnSeS is 85%, which is about 3% lower than that of the unmodified green CdZnSeS (88%); the QY of the modified red CdZnSeS is 85%, which is comparable to that of the unmodified red CdZnSeS (85%). ) did not decrease. In addition, the luminescence peak (PL peak) of the modified quantum dots shows that the peak red shift is less than 1-3 nm, which confirms that the modified quantum dots have a good dispersion state (generally, if the quantum dots are not dispersed, the red shift will be greater than 5-15 nm). .

Example 2

Embodiment 2 provides a kind of preparation method of quantum dot master batch, and its preparation method is as follows: Description: Weigh 50g of modified quantum dots prepared in Example 1 and 3,950g of polystyrene (Chi Mei PH-88) and mix them evenly, then add to the extruder feed funnel, the feed temperature is 220°C, and the discharge temperature 200 ° C, water cooling, dicing, drying, that is, it is obtained. The modified quantum dots prepared in Example 1 are respectively modified red CdZnSeS and modified green CdZnSeS.

Take a small amount of quantum dot masterbatch and dissolve it in toluene, measure quantum yield (Quantum yield, QY), emission wavelength (λ) and half-peak width (FWHM), and compare the obtained data with the modified quantum dots. The results are shown in Table 2. The results of the QY quantity test found that the quantum yield decreased significantly after granulation. The QY of the red modified quantum dots dropped from 85% to 61%, and the QY of the green modified quantum dots dropped from 85% to 40%. It is affected by high temperature oxidation during the granulation process. In addition, the luminescence peak (PL peak) of the modified quantum dots shows that the peak red shift is less than 1~3 nm.

Example 3

Embodiment 3 provides a quantum dot masterbatch, and its preparation method is as follows: mixing the modified quantum dots and aromatic compounds obtained in embodiment 1, and then mixing with polystyrene (Chi Mei PH-88) uniformly. , into the extruder feeding funnel, the feeding temperature is 220 ° C, the discharging temperature is 200 ° C, water cooling, dicing, drying, that is, it is obtained. In this example, a master batch containing one aromatic compound and a master batch containing two aromatic compounds were prepared respectively, and the raw material consumption of each master batch is shown in Table 3.

The modified quantum dots prepared in the embodiment 1 are respectively modified red CdZnSeS and modified red CdZnSeS. green CdZnSeS; the aromatic compound is tetrakis[beta-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester (CAS number: 6683-19-8) and/or tri[ 2,4-Di-tert-butylphenyl]phosphite (CAS number: 31570-04-4).

Get a small amount of quantum dot master batch and be dissolved in toluene in the present embodiment, measure quantum yield (Quantum yield, QY), luminescence wavelength (λ) and half-peak width (FWHM), the obtained data is compared with Example 2, the results are shown in the table 3. According to the test results, it can be seen that the masterbatch containing two aromatic compounds has the best effect, which can increase the quantum yield retention ratio (EQY/AQY) of green quantum dots from 0.45 to 0.74, and the quantum yield of red quantum dots from 0.45 to 0.74. 0.72 increased to 0.94. Figure 3 shows the masterbatch containing no aromatic compounds and modified red CdZnSeS (top left), the masterbatch containing aromatic compounds and modified red CdZnSeS (top right), and the masterbatch containing no aromatic compounds and modified green CdZnSeS Sample images of the masterbatch (bottom left) and the masterbatch containing aromatic compounds and modified green CdZnSeS (bottom right), from the appearance of the quantum dot masterbatch, it can be observed that the quantum dot masterbatch added with aromatic compounds shows brighter fluorescence color.

Finally, it is pointed out that the above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection of the invention.

Claims (3)

A method for preparing modified quantum dots, the preparation raw materials include: a quantum dot, the weight ratio of the quantum dot to a modifier is 1: (2~20); the quantum yield maintenance rate of the modified quantum dot

90%, the quantum dots are composed of three kinds of ternary alloy materials of Cd, Zn, Se, S, In, and P and/or quaternary alloys composed of four kinds of Cd, Zn, Se, S, In, and P. alloy material; a modifier, the modifier is an acrylic polymer with a weight average molecular weight of 5,000-100,000; a polymerized monomer of the acrylic polymer, the polymerized monomer of the acrylic polymer is selected from methyl methacrylate , one or more of methacrylic acid, lauryl methacrylate, methyl acrylate, acrylic acid, butyl acrylate, methyl acrylate, ethyl acrylate, isooctyl acrylate, ethyl methacrylate, butyl methacrylate The preparation method of the modified quantum dots includes the following steps: dissolving the quantum dots and the modifier in a benign solvent respectively, mixing the two solutions, adding the mixed solution to the poor solvent after the reaction is completed, precipitating out, removing Solvent, drying and precipitation, pulverization, that is, it is obtained. The method for preparing modified quantum dots according to item 1 of the claimed scope, characterized in that the weight ratio of the quantum dots to the benign solvent dissolving the quantum dots is 1:(4~5); the modifier The concentration after dissolving in benign solvent is 20~40wt%. A preparation method of quantum dot master batch, the preparation raw materials include: 1~5wt% of modified quantum dots, 0.5~20wt% of aromatic compounds as described in item 1 of the patent application scope, and the remainder is resin; From allyl diethylene glycol dicarbonate, polymethyl methacrylate, polystyrene, polycarbonate, poly-4-methyl-1-pentene, styrene-acrylonitrile copolymer, polymethyl methacrylate - a mixture of one or more of styrene copolymers and cycloolefin polymers; the aromatic compound is selected from 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethyl) Benzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyl) Benzyl)isocyanuric acid, β- (3,5-di-tert-butyl-4-hydroxyphenyl)isooctyl propionate, β- (3,5-di-tert-butyl-4-hydroxyphenyl) Stearyl propionate, 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tetrakis[beta-(3,5 - Mixing of one or more of di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester and tris[2,4-di-tert-butylphenyl] phosphite; preparation of quantum dot masterbatch The method includes the following steps: mixing the modified quantum dots, aromatic compounds and resin, extruding and granulating, and the process temperature is 150-250 DEG C.

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