Preparation method and application of melamine-formaldehyde modified mxene

Abstract

The application provides a preparation method and application of melamine-formaldehyde modified Mxene, first, melamine-formaldehyde prepolymer is synthesized, then Mxene is prepared by stripping aluminum carbide through a lithium fluoride acid solution, finally, the melamine-formaldehyde prepolymer and the stripped Mxene are in-situ polymerized to obtain melamine-formaldehyde modified Mxene, the melamine-formaldehyde modified Mxene is compounded with each component of ink, and grinding and filtering are carried out, so that high-efficiency heat-conducting UV-LED ink is obtained, the melamine-formaldehyde resin is used for embedding treatment of Mxene, so that the dispersibility of Mxene is improved, the technical problem of poor compatibility of Mxene and an ink matrix is solved, and then, the connecting material, the pigment and various kinds of additives are supplemented, UV-LED heat-conducting ink is prepared, the agglomeration of Mxene is effectively prevented, and the heat conductivity of the heat-conducting ink is greatly improved, and the heat conductivity coefficient of the ink film after printing is up to 1.32 W / m.K in the plane direction.

Description

[0001] This application is a divisional application. The original application has the application number 2021115569725, the application date is December 18, 2021, and the invention title is "A method for preparing a high-efficiency thermally conductive UV-LED ink and its application". Technical Field

[0002] This invention belongs to the field of polymer ink technology, specifically relating to a method for preparing melamine-formaldehyde modified Mxene and its application. Background Technology

[0003] With the increasing maturity of 5G technology, electronic devices are gradually developing towards miniaturization, high integration, and intelligence. The resulting heat accumulation problem has become a key factor affecting the lifespan of electronic devices. Numerous studies have shown that within a suitable operating temperature range, for every 1°C decrease in the operating temperature of an electronic device, its failure rate decreases by 4%; however, when the temperature exceeds the maximum set temperature by 20°C, the failure rate reaches 100%. Therefore, the development of high-performance heat dissipation materials has become an important issue in the current application field of electronic devices.

[0004] Numerous scholars and research institutions have conducted extensive research on heat dissipation materials, such as graphene, boron nitride, aluminum oxide, carbon nanotubes, and nanodiamonds. These thermally conductive materials have been developed and applied to heat dissipation in electronic products, achieving significant research results. However, when focusing on the commercialization of electronic products, it's easy to see that another important issue is often overlooked: electronic products are printed with ink to indicate information. After the ink dries on the surface of the electronic product, it forms a dense ink layer, and the binder in the ink solidifies into a film, firmly adhering to the surface of the electronic device and hindering heat dissipation. Therefore, developing a functional ink that can both meet the printing requirements of electronic products and dissipate heat effectively has become an important task. In this context, thermally conductive inks have emerged. Thermally conductive inks are based on traditional inks with the addition of fillers or additives with thermally conductive properties to give the ink excellent thermal conductivity. Compared with traditional inks, UV-LED inks not only have a fast curing rate but also low energy consumption. Combining them with thermally conductive fillers holds promise for developing new types of highly efficient and fast-drying thermally conductive inks.

[0005] Among numerous thermally conductive fillers, graphene boasts a thermal conductivity as high as 5300 W / m·K, but its cost is high and it has been extensively studied. Materials such as boron nitride and aluminum oxide are often added in large quantities when preparing thermally conductive inks, which can affect the ink's basic properties. In contrast, Mxene, as a novel two-dimensional material, possesses significant advantages such as exfoliability, high thermal conductivity, unique size effect, and strong heat dissipation capacity. Furthermore, its raw material, titanium aluminum carbide (Ti3AlC2)MAX, is relatively inexpensive, making it a promising new material in the field of thermal conductivity and attracting widespread attention from academia and industry. However, since Mxene is an inorganic filler, its direct addition to the ink matrix often results in poor compatibility and dispersion difficulties, leading to less than ideal thermal conductivity in commonly prepared thermally conductive inks. Summary of the Invention

[0006] This invention addresses the problem of poor compatibility between Mxene and ink matrix by providing a method for preparing melamine-formaldehyde modified Mxene and its application.

[0007] A method for preparing melamine-formaldehyde modified Mxene, applicable to thermally conductive inks, wherein the melamine-formaldehyde modified Mxene is obtained through the following steps: synthesizing melamine-formaldehyde prepolymer, preparing Mxene by exfoliating titanium aluminum carbide with lithium fluoride solution, and in-situ polymerizing the melamine-formaldehyde prepolymer with the exfoliated Mxene to obtain melamine-formaldehyde modified Mxene.

[0008] The principle of this invention:

[0009] By utilizing the in-situ polymerization of Mxene using melamine-formaldehyde resin, the aggregation of Mxene is effectively reduced, the dispersibility of Mxene in ink is improved, and the thermal conductivity of the ink is significantly increased.

[0010] The melamine-formaldehyde modified Mxene was prepared by the following steps:

[0011] (1) Add melamine to a polar solution and stir evenly. Set the temperature to 50-80℃, slowly add formaldehyde solution with a mass fraction of 30-40%, adjust the pH to 7-10 with a weak base, react for 1-2 hours, and after the reaction is complete, continue stirring for 30-60 minutes. After standing, melamine-formaldehyde prepolymer is obtained.

[0012] (2) Add lithium fluoride to an acidic solution and stir to dissolve. Add titanium aluminum carbide powder and stir to react at 30-60℃ for 4-48 hours. Wash with deionized water until the pH is between 5 and 9. Place in an ultrasonic cleaner and ultrasonically peel for 5-60 minutes with the power set to 100-400W. After peeling, centrifuge the reaction solution at 1000-10000r / min for 10-30 minutes. Take the lower precipitate and dry it in a drying oven to obtain Mxene.

[0013] (3) Add Mxene to a polar solvent and sonicate at 30-80℃ for 30-90 minutes to obtain Mxene dispersion. Then add it to the melamine-formaldehyde prepolymer prepared in step (1), stir for 4-8 hours, set the temperature to 50-100℃, and the stirring speed to 300-1000r / min. Filter and vacuum dry to obtain melamine-formaldehyde modified Mxene.

[0014] In the melamine-formaldehyde modified Mxene preparation method described above, the molar ratio of melamine to formaldehyde is 1:5-10.

[0015] In the melamine-formaldehyde modified Mxene preparation method described above, the mass ratio of lithium fluoride to titanium aluminum carbide is 1:1-10.

[0016] In the melamine-formaldehyde modified Mxene preparation method described above, the mass ratio of Mxene to melamine is 1:1-20.

[0017] In the preparation method of melamine-formaldehyde modified Mxene as described above, in step (1):

[0018] The polar solvent is water;

[0019] The melamine, when added to a polar solvent, has a solid content of 5-30%.

[0020] The weak base mentioned is one of sodium carbonate, sodium bicarbonate, or ammonia water.

[0021] As described above, in the preparation method of melamine-formaldehyde modified Mxene: in step (2):

[0022] The acidic solution is one of hydrochloric acid, sulfuric acid, or nitric acid;

[0023] The concentration of the lithium fluoride solution is 1.00-20.00 mg / ml.

[0024] In the preparation method of melamine-formaldehyde modified Mxene as described above, in step (3):

[0025] The polar solvent is one of N,N-dimethylacetamide, N-methylpyrrolidone, or isopropanol;

[0026] The concentration of the Mxene dispersion is 0.08-10 mg / ml;

[0027] The power of the ultrasound is 100-325W;

[0028] The vacuum drying conditions are preferably 25-100℃ for 4-20 hours.

[0029] Application of melamine-formaldehyde modified Mxene prepared by the above method in thermally conductive inks.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] This application provides a method for preparing melamine-formaldehyde modified Mxene. First, a melamine-formaldehyde prepolymer is synthesized. Then, Mxene is prepared by exfoliating titanium aluminum carbide with lithium fluoride solution. Finally, the melamine-formaldehyde prepolymer and the exfoliated Mxene are polymerized in situ to obtain melamine-formaldehyde modified Mxene. The melamine-formaldehyde modified Mxene is then compounded with the components of the ink, ground, and filtered to obtain a high-efficiency thermally conductive UV-LED ink. This invention uses melamine-formaldehyde resin to embed Mxene to improve the dispersibility of Mxene and solve the technical problem of poor compatibility between Mxene and the ink matrix. With the addition of binders, pigments, and various additives, a UV-LED thermally conductive ink is prepared. This not only effectively prevents the agglomeration of Mxene but also greatly improves the thermal conductivity of the ink. The thermal conductivity of the printed ink film in the planar direction is as high as 1.32 W / m·K.

[0032] This application provides an application of melamine-formaldehyde modified Mxene, a high-efficiency thermally conductive UV-LED ink that can be used in the printing and packaging decoration of electronic appliances. This invention solves the problems of poor compatibility and difficulty in dispersion of Mxene when added to the ink matrix. The prepared thermally conductive functional filler has the advantages of low addition amount and good thermal conductivity, which greatly improves the thermal conductivity of the ink. Moreover, the preparation method of this high-efficiency thermally conductive UV-LED ink is simple and easy to operate. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0034] Figure 1 These are SEM images of Mxene and melamine-formaldehyde resin-modified Mxene.

[0035] Figure 2 This is an infrared image of the melamine-formaldehyde resin-modified Mxene prepared in Example 5.

[0036] Figure 3 This is a test graph of the thermal conductivity of the high-efficiency thermally conductive UV-LED ink prepared in Example 5. Detailed Implementation

[0037] The specific technical solutions of the present invention are described below with reference to specific embodiments 1-8:

[0038] Example 1

[0039] A method for preparing a high-efficiency thermally conductive UV-LED ink includes the following steps:

[0040] (1) Take 6g of melamine and add it to 60mL of deionized water. Stir at 300r / min. Then add 14mL (37%) of formaldehyde solution. Adjust the pH to 9 with freshly prepared Na2CO3 (10%) solution. Heat to 80℃ and continue stirring for 20 minutes to obtain melamine-formaldehyde prepolymer.

[0041] (2) Take 1.0 g of lithium fluoride and add it to 150 mL of HCl. Stir for 5 minutes, then add 2.0 g of titanium aluminum carbide powder. Stir and react for 8 hours at 30 °C. Wash with deionized water until the pH is 5.5. Place the mixture in an ultrasonic cleaner and ultrasonically peel it for 10 minutes at a power of 200 W. After peeling, centrifuge the reaction solution at 2000 r / min for 10 minutes. Take the lower precipitate and dry it in a drying oven to obtain Mxene.

[0042] (3) Take 1.0g of Mxene and add it to 300mL of N-methylpyrrolidone. Sonicate at 50℃ for 40 minutes with a power of 250w to obtain Mxene dispersion. Then add it to the melamine-formaldehyde prepolymer prepared in step (1), stir for 3 hours, set the temperature to 50℃ and the stirring speed to 350r / min. After filtration, dry at 80℃ for 2 hours to obtain melamine-formaldehyde modified Mxene (MF@Mxene).

[0043] (4) The melamine-formaldehyde modified Mxene (MF@Mxene), polyurethane acrylate, epoxy acrylate, diethylene glycol diacrylate, photoinitiator and leveling agent, defoamer, dispersant and wetting agent obtained in step (3) are added to a high-speed disperser at proportions of 0.5%, 35%, 15%, 35%, 8%, 2%, 1%, 1% and 2.5% relative to the total mass of ink, respectively. The disperser is dispersed at 2000 r / min for 2 hours, then pulverized and ground with a three-roll mill for 3 hours. Finally, the ink is filtered through a 300-mesh screen to obtain a high-efficiency thermally conductive UV-LED thermally conductive ink.

[0044] Example 2

[0045] A method for preparing a high-efficiency thermally conductive UV-LED ink includes the following steps:

[0046] (1) Take 4g of melamine and add it to 40mL of deionized water. Stir at 200r / min. Then add 7.2mL (37%) of formaldehyde solution. Adjust the pH to 8 with freshly prepared Na2CO3 (10%) solution. Heat to 70℃ and continue stirring for 30 minutes to obtain melamine-formaldehyde prepolymer.

[0047] (2) Take 1.5g of lithium fluoride and add it to 200mL of HCl. Stir for 10 minutes, then add 2.5g of aluminum titanium carbide powder. Stir and react at 40℃ for 10 hours. Wash with deionized water until pH 6. Place in an ultrasonic cleaner and ultrasonically peel for 15 minutes at a power of 200W. After peeling, centrifuge the reaction solution at 2500r / min for 15 minutes. Take the lower precipitate and dry it in a drying oven to obtain Mxene.

[0048] (3) Take 1.5g of Mxene and add it to 500mL of N-methylpyrrolidone. Sonicate at 40℃ for 60 minutes with a power of 100w to obtain Mxene dispersion. Then add it to the melamine-formaldehyde prepolymer prepared in step (1). Stir for 4 hours at a set temperature of 50℃ and a stirring speed of 400r / min. After filtration, dry at 60℃ for 8 hours to obtain melamine-formaldehyde modified Mxene (MF@Mxene).

[0049] (4) The melamine-formaldehyde modified Mxene (MF@Mxene), polyurethane acrylate, epoxy acrylate, diethylene glycol diacrylate, photoinitiator and leveling agent, defoamer, dispersant and wetting agent obtained in step (3) are added to a high-speed disperser at proportions of 1%, 35%, 10%, 45%, 3%, 2%, 1%, 1% and 2% relative to the total mass of ink, respectively. The disperser is dispersed at 4000 r / min for 1 hour, then pulverized and ground with a three-roll mill for 1 hour, and finally filtered through a 200-mesh screen to obtain a high-efficiency thermally conductive UV-LED thermally conductive ink.

[0050] Example 3

[0051] A method for preparing a high-efficiency thermally conductive UV-LED ink includes the following steps:

[0052] (1) Take 3g of melamine and add it to 35mL of deionized water. Stir at 250r / min. Then add 7.5mL (37%) of formaldehyde solution. Adjust the pH to 10 with freshly prepared Na2CO3 (10%) solution. Heat to 60℃ and continue stirring for 40 minutes to obtain melamine-formaldehyde prepolymer.

[0053] (2) Take 2.0 g of lithium fluoride and add it to 400 mL of HCl. Stir for 15 minutes, then add 5 g of titanium aluminum carbide powder. Stir and react at 40 °C for 15 hours. Wash with deionized water until pH 7. Place in an ultrasonic cleaner and ultrasonically peel for 20 minutes at a power of 300 W. After peeling, centrifuge the reaction solution at 3000 r / min for 10 minutes. Take the lower precipitate and dry it in a drying oven to obtain Mxene.

[0054] (3) Take 4g of Mxene and add it to 450mL of N-methylpyrrolidone. Sonicate at 60℃ for 30 minutes with a power of 150w to obtain Mxene dispersion. Then add it to the melamine-formaldehyde prepolymer prepared in step (1). Stir for 2 hours at a set temperature of 60℃ and a stirring speed of 300r / min. After filtration, dry at 70℃ for 6 hours to obtain melamine-formaldehyde modified Mxene (MF@Mxene).

[0055] (4) The melamine-formaldehyde modified Mxene (MF@Mxene), polyurethane acrylate, epoxy acrylate, diethylene glycol diacrylate, photoinitiator and leveling agent, defoamer, dispersant and wetting agent obtained in step (3) are added to a high-speed disperser at proportions of 1.5%, 20%, 25%, 40%, 6%, 3.5%, 1.5%, 2% and 0.5% relative to the total mass of ink, respectively. The disperser is dispersed at 3000 r / min for 2 hours, then pulverized and ground with a three-roll mill for 2 hours, and finally filtered through a 200-mesh screen to obtain a high-efficiency thermally conductive UV-LED thermally conductive ink.

[0056] Example 4

[0057] A method for preparing a high-efficiency thermally conductive UV-LED ink includes the following steps:

[0058] (1) Take 10g of melamine and add it to 30mL of deionized water. Stir at 300r / min. Then add 18.9mL (37%) of formaldehyde solution. Adjust the pH to 10 with freshly prepared NaHCO3 (10%) solution. Heat to 70℃ and continue stirring for 40 minutes to obtain melamine-formaldehyde prepolymer.

[0059] (2) Take 2.5g of lithium fluoride and add it to 400mL of HCl. Stir for 20 minutes, then add 6g of titanium aluminum carbide powder. Stir and react at 50℃ for 20 hours. Wash with deionized water until pH is 8. Place in an ultrasonic cleaner and ultrasonically peel for 30 minutes at a power of 300W. After peeling, centrifuge the reaction solution at 3500r / min for 20 minutes. Take the lower precipitate and dry it in a drying oven to obtain Mxene.

[0060] (3) Take 4.5g of Mxene and add it to 450mL of N-methylpyrrolidone. Sonicate at 50℃ for 60 minutes with a power of 350w to obtain Mxene dispersion. Then add it to the melamine-formaldehyde prepolymer prepared in step (1), stir for 1 hour, set the temperature to 40℃ and the stirring speed to 300r / min. After filtration, dry at 70℃ for 3 hours to obtain melamine-formaldehyde modified Mxene (MF@Mxene).

[0061] (4) The melamine-formaldehyde modified Mxene (MF@Mxene), polyurethane acrylate, epoxy acrylate, diethylene glycol diacrylate, photoinitiator and leveling agent, defoamer, dispersant and wetting agent obtained in step (3) are added to a high-speed disperser at proportions of 2%, 25%, 25%, 35%, 3%, 3.5%, 1%, 3.5% and 2% relative to the total mass of ink, respectively. The disperser is dispersed at 3500 r / min for 2 hours, then pulverized and ground with a three-roll mill for 2 hours. Finally, the ink is filtered through a 250 mesh screen to obtain a high-efficiency thermally conductive UV-LED thermally conductive ink.

[0062] Example 5

[0063] A method for preparing a high-efficiency thermally conductive UV-LED ink includes the following steps:

[0064] (1) Take 5g of melamine and add it to 60mL of deionized water. Stir at 300r / min. Then add 8.9mL (37%) of formaldehyde solution. Adjust the pH to 10 with freshly prepared Na2CO3 (10%) solution. Heat to 70℃ and continue stirring for 60 minutes to obtain melamine-formaldehyde prepolymer.

[0065] (2) Take 3.0 g of lithium fluoride and add it to 500 mL of HCl. Stir for 10 minutes, then add 3.0 g of titanium aluminum carbide powder. Stir and react at 42 °C for 24 hours. Wash with deionized water until pH 6. Place in an ultrasonic cleaner and ultrasonically peel for 30 minutes at a power of 300 W. After peeling, centrifuge the reaction solution at 3500 r / min for 30 minutes. Take the lower precipitate and dry it in a drying oven to obtain Mxene.

[0066] (3) Take 1.0g of Mxene and add it to 500mL of N-methylpyrrolidone. Sonicate at 50℃ for 90 minutes with a power of 325w to obtain Mxene dispersion. Then add it to the melamine-formaldehyde prepolymer prepared in step (1), stir for 2 hours, set the temperature to 50℃ and the stirring speed to 300r / min. After filtration, dry at 80℃ for 3 hours to obtain melamine-formaldehyde modified Mxene (MF@Mxene).

[0067] (4) The melamine-formaldehyde modified Mxene (MF@Mxene), polyurethane acrylate, epoxy acrylate, diethylene glycol diacrylate, photoinitiator and leveling agent, defoamer, dispersant and wetting agent obtained in step (3) are added to a high-speed disperser at proportions of 3%, 30%, 10%, 40%, 5%, 2%, 3%, 2% and 3% relative to the total mass of ink, respectively. The disperser is dispersed at 3000 r / min for 2 hours, then pulverized and ground with a three-roll mill for 2 hours, and finally filtered through a 250 mesh screen to obtain a high-efficiency thermally conductive UV-LED thermally conductive ink.

[0068] Example 6

[0069] A method for preparing a high-efficiency thermally conductive UV-LED ink includes the following steps:

[0070] (1) Take 8g of melamine and add it to 100mL of deionized water. Stir at 500r / min. Then add 15mL (37%) of formaldehyde solution. Adjust the pH to 10 with freshly prepared ammonia (10%) solution. Heat to 60℃ and continue stirring for 60 minutes to obtain melamine-formaldehyde prepolymer.

[0071] (2) Take 4.0 g of lithium fluoride and add it to 500 mL of HCl. Stir for 15 minutes, then add 6.0 g of aluminum titanium carbide powder. Stir and react at 45 °C for 18 hours. Wash with deionized water until pH 9. Place in an ultrasonic cleaner and ultrasonically peel for 30 minutes at a power of 150 W. After peeling, centrifuge the reaction solution at 4000 r / min for 35 minutes. Take the lower precipitate and dry it in a drying oven to obtain Mxene.

[0072] (3) Take 4.0g of Mxene and add it to 500mL of N-methylpyrrolidone. Sonicate at 60℃ for 40 minutes with a power of 300w to obtain Mxene dispersion. Then add it to the melamine-formaldehyde prepolymer prepared in step (1). Stir for 2.5 hours at a temperature of 60℃ and a stirring speed of 500r / min. After filtration, dry at 60℃ for 3 hours to obtain melamine-formaldehyde modified Mxene (MF@Mxene).

[0073] (4) The melamine-formaldehyde modified Mxene (MF@Mxene), polyurethane acrylate, epoxy acrylate, diethylene glycol diacrylate, photoinitiator and leveling agent, defoamer, dispersant and wetting agent obtained in step (3) are added to a high-speed disperser at proportions of 5%, 35%, 15%, 30%, 8%, 3%, 3%, 0.5% and 0.5% relative to the total mass of ink, respectively. The disperser is dispersed at 3000 r / min for 2 hours, then pulverized and ground with a three-roll mill for 3 hours. Finally, the ink is filtered through a 500-mesh screen to obtain a high-efficiency thermally conductive UV-LED thermally conductive ink.

[0074] Example 7

[0075] A method for preparing a high-efficiency thermally conductive UV-LED ink includes the following steps:

[0076] (1) Take 6.5g of melamine and add it to 90mL of deionized water. Stir at 800r / min. Then add 18mL (37%) of formaldehyde solution. Adjust the pH to 10 with freshly prepared ammonia (10%) solution. Heat to 75℃ and continue stirring for 50 minutes to obtain melamine-formaldehyde prepolymer.

[0077] (2) Take 5.0 g of lithium fluoride and add it to 500 mL of HCl. Stir for 30 minutes, then add 6.0 g of aluminum titanium carbide powder. Stir and react at 50 °C for 36 hours. Wash with deionized water until pH 8. Place in an ultrasonic cleaner and ultrasonically peel for 15 minutes at a power of 250 W. After peeling, centrifuge the reaction solution at 3000 r / min for 35 minutes. Take the lower precipitate and dry it in a drying oven to obtain Mxene.

[0078] (3) Take 5.0g of Mxene and add it to 500mL of N-methylpyrrolidone. Sonicate at 60℃ for 60 minutes with a power of 300w to obtain Mxene dispersion. Then add it to the melamine-formaldehyde prepolymer prepared in step (1), stir for 3 hours, set the temperature to 60℃ and the stirring speed to 300r / min. After filtration, dry at 50℃ for 2 hours to obtain melamine-formaldehyde modified Mxene (MF@Mxene).

[0079] (4) The melamine-formaldehyde modified Mxene (MF@Mxene), polyurethane acrylate, epoxy acrylate, diethylene glycol diacrylate, photoinitiator and leveling agent, defoamer, dispersant and wetting agent obtained in step (3) are added to a high-speed disperser at proportions of 6%, 30%, 15%, 35%, 4%, 3%, 2%, 2.5% and 2.5% relative to the total mass of ink, respectively. The disperser is dispersed at 5000 r / min for 2 hours, then pulverized and ground with a three-roll mill for 1 hour, and finally filtered through an 800-mesh screen to obtain a high-efficiency thermally conductive UV-LED thermally conductive ink.

[0080] Example 8

[0081] A method for preparing a high-efficiency thermally conductive UV-LED ink includes the following steps:

[0082] (1) Take 7g of melamine and add it to 120mL of deionized water. Stir at 600r / min. Then add 20mL (37%) of formaldehyde solution. Adjust the pH to 9 with freshly prepared ammonia (10%) solution. Heat to 80℃ and continue stirring for 60 minutes to obtain melamine-formaldehyde prepolymer.

[0083] (2) Take 6.0 g of lithium fluoride and add it to 800 mL of HCl. Stir for 40 minutes, then add 6.0 g of aluminum titanium carbide powder. Stir and react at 60 °C for 40 hours. Wash with deionized water until pH 7. Place in an ultrasonic cleaner and ultrasonically peel for 25 minutes at a power of 300 W. After peeling, centrifuge the reaction solution at 3500 r / min for 30 minutes. Take the lower precipitate and dry it in a drying oven to obtain Mxene.

[0084] (3) Take 5.0g of Mxene and add it to 350mL of N-methylpyrrolidone. Sonicate at 80℃ for 40 minutes with a power of 300w to obtain Mxene dispersion. Then add it to the melamine-formaldehyde prepolymer prepared in step (1), stir for 2 hours, set the temperature to 70℃ and the stirring speed to 300r / min. After filtration, dry at 80℃ for 2 hours to obtain melamine-formaldehyde modified Mxene (MF@Mxene).

[0085] (4) The melamine-formaldehyde modified Mxene (MF@Mxene), polyurethane acrylate, epoxy acrylate, diethylene glycol diacrylate, photoinitiator and leveling agent, defoamer, dispersant and wetting agent obtained in step (3) are added to a high-speed disperser at proportions of 7%, 35%, 13%, 35%, 8%, 0.5%, 0.5%, 0.5% and 0.5% relative to the total mass of ink, respectively. The disperser is dispersed at 6000 r / min for 2 hours, then pulverized and ground with a three-roll mill for 1.5 hours. Finally, the ink is filtered through an 800-mesh screen to obtain a high-efficiency thermally conductive UV-LED thermally conductive ink.

[0086] Effect Example

[0087] Scanning electron microscopy (SEM) was performed on the raw material Mxene and the intermediate product melamine-formaldehyde functionalized Mxene from Example 1. The results were obtained from the scanning electron microscope images (…). Figure 1 As can be seen, compared with Mxene, Mxene after being encapsulated in melamine-formaldehyde resin has a very rough surface and is obviously loaded with many fine particles.

[0088] Meanwhile, the in-plane thermal conductivity of the high-efficiency thermally conductive UV-LED inks prepared in Examples 1-8 was tested and compared with that of thermally conductive inks reported in the prior art (Table 1). As can be seen from Table 1, the thermal conductivity of the high-efficiency thermally conductive UV-LED inks prepared in this invention is significantly higher than that of thermally conductive inks reported in the prior art, even with extremely low addition amounts.

[0089] Table 1 Comparison of thermal conductivity

[0090]

[0091]

[0092] As shown in Table 1, the high-efficiency thermally conductive UV-LED ink of this application can greatly improve the thermal conductivity of the ink with a small amount of melamine-formaldehyde modified Mxene thermally conductive filler. When the amount is only 3.0 wt%, the thermal conductivity of the ink film after printing is as high as 1.32 W / m·K in the planar direction. The above-mentioned Example 5 is a preferred embodiment of the present invention, but the embodiments of the present invention are not limited to the above-mentioned embodiments. Any changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention should be considered as equivalent substitutions and are included within the protection scope of the present invention.

Claims

1. A method for preparing melamine-formaldehyde modified Mxene, applied to thermally conductive inks, characterized in that, The melamine-formaldehyde modified Mxene was prepared by the following steps: (1) Melamine is added to a polar solution and stirred evenly. The polar solution is water. The solid content of melamine after being added to the polar solution is 5-30%. The temperature is set at 50-80℃. Formaldehyde solution with a mass fraction of 30-40% is slowly added. The pH is adjusted to 7-10 with a weak base, which is sodium carbonate, sodium bicarbonate or ammonia water. The reaction is carried out for 1-2 hours. After the reaction is completed, stirring is continued for 30-60 minutes. After standing, melamine-formaldehyde prepolymer is obtained. (2) Add lithium fluoride to an acidic solution and stir to dissolve it. The acidic solution is one of hydrochloric acid, sulfuric acid or nitric acid. The concentration of the lithium fluoride acid solution is 1.00-20.00 mg / ml. Add titanium aluminum carbide powder and stir to react at 30-60℃ for 4-48 hours. Wash with deionized water until the pH is between 5 and 9. Place it in an ultrasonic cleaner and ultrasonically peel it for 5-60 minutes. Set the power to 100-400W. After peeling, centrifuge the reaction solution at 1000-10000 r / min for 10-30 minutes. Take the lower precipitate and dry it in a drying oven to obtain Mxene. (3) Add Mxene to a polar solvent and sonicate at 30-80℃ for 30-90 minutes to obtain Mxene dispersion. Then add it to the melamine-formaldehyde prepolymer prepared in step (1), stir for 4-8 hours, set the temperature to 50-100℃, and the stirring speed to 300-1000r / min. Filter and vacuum dry to obtain melamine-formaldehyde modified Mxene.

2. The preparation method of melamine-formaldehyde modified Mxene according to claim 1, characterized in that: The molar ratio of melamine to formaldehyde is 1:5-10.

3. The preparation method of melamine-formaldehyde modified Mxene according to claim 1, characterized in that: The mass ratio of lithium fluoride to titanium aluminum carbide is 1:1-10.

4. The preparation method of melamine-formaldehyde modified Mxene according to claim 1, characterized in that: The mass ratio of Mxene to melamine is 1:1-20.

5. The preparation method of melamine-formaldehyde modified Mxene according to claim 1, characterized in that: In step (3): The polar solvent is one of N,N-dimethylacetamide, N-methylpyrrolidone, or isopropanol; The concentration of the Mxene dispersion is 0.08-10 mg / ml; The power of the ultrasound is 100-325W; The vacuum drying conditions are as follows: drying at a temperature of 25-100℃ for 4-20 hours.

6. The application of melamine-formaldehyde modified Mxene prepared by the preparation method according to any one of claims 1-5 in thermally conductive inks.

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