Hot melt adhesive with far infrared function and preparation method thereof

Abstract

The invention belongs to the technical field of hot melt adhesive film production, and particularly relates to a hot melt adhesive with a far infrared function and a preparation method thereof, and the preparation method comprises the following steps: S1, synthesizing a photoresponse liquid crystal monomer (Azo-LC); the preparation method comprises the following steps: preparing 4-cyano-4 '-amyl azobenzene through a diazotization reaction, a coupling reaction and post-treatment in sequence, and then introducing a dynamic covalent bond (synthesizing DA-Azo-LC); s2, functional modification of the quantum dots; sequentially carrying out acidification reaction and washing to carry out carboxylation treatment on the GQDs, carrying out CsPbBr3 amino modification through ligand exchange and purification, and hybridizing the carboxylated GQDs and the aminated CsPbBr3; s3, preparing and coating a precursor solution; and S4, carrying out magnetic field-light field synergistic orientation and curing. The azobenzene group is subjected to cis-isomerization under 365nm ultraviolet light and is recovered to trans-isomerization under 450nm blue light, and the arrangement density of liquid crystal molecules can be dynamically adjusted by the conformation change, so that the absorption and emission efficiency of the material to far infrared rays is changed.

Description

Technical Field

[0001] The present invention belongs to the technical field of molten adhesive film production, and particularly relates to a hot melt adhesive with far-infrared function and a preparation method thereof. Background Art

[0002] The hot melt adhesive with far-infrared function is a new type of functional adhesive that adds far-infrared radiation materials on the basis of traditional hot melt adhesives. It can emit far-infrared rays while bonding, endowing the product with additional thermal effects or health care functions. Commonly used thermoplastic polymers such as EVA (ethylene-vinyl acetate), PU (polyurethane), and PA (polyamide) are used to provide bonding performance. The additive emits far-infrared rays with a wavelength of 3μm - 1mm under the excitation of heat or external energy, having permeability and thermal effects, and promoting local temperature rise or blood circulation of biological tissues;

[0003] Currently, when preparing the hot melt adhesive with far-infrared function in the prior art, generally, the base polymer, far-infrared additive, tackifying resin, antioxidant, etc. are fully mixed and homogenized in a mixer according to a certain ratio to form a premix, and then the premix is added to a twin-screw extruder and heated to a certain temperature to melt the material, usually around 150 - 200°C, and the specific temperature depends on the characteristics of raw materials such as the selected base polymer. Under the rotation and pushing of the screw, the material is fully mixed and sheared in the extruder, so that the far-infrared additive is evenly dispersed in the base polymer.

[0004] However, for the hot melt adhesive with far-infrared function prepared by the existing preparation method, since the addition of the far-infrared radiation material is fixed, its far-infrared emissivity is fixed. In view of this, the present invention provides a hot melt adhesive with far-infrared function and a preparation method thereof. Summary of the Invention

[0005] To achieve the above object, the present invention provides the following technical solution: A preparation method of a hot melt adhesive with far-infrared function, comprising the following steps:

[0006] S1: Synthesize a photo-responsive liquid crystal monomer (Azo-LC);

[0007] After preparing 4-cyano-4'-pentylazobenzene by diazotization reaction, coupling reaction and post-treatment in sequence, introduce a dynamic covalent bond (synthesize DA-Azo-LC);

[0008] S2: Quantum dot functionalization modification;

[0009] Carry out carboxylation treatment of GQDs by acidification reaction and washing in sequence, then carry out amino modification of CsPbBr3 by ligand exchange and purification, and then hybridize carboxylated GQDs with aminoated CsPbBr3;

[0010] S3: Preparation and coating of the precursor solution;

[0011] The precursor solution is prepared by stirring and mixing DA-Azo-LC, hybrid quantum dots, Irgacure 819, and THF in proportion, and then the precursor solution is dropped onto the PI-based film treated with oxygen plasma by a spin coater.

[0012] S4: Magnetic field-light field synergistic orientation and curing;

[0013] The coated base film is placed in the center of a superconducting magnet. After magnetic field-polarized light induced orientation is carried out by turning on polarized blue light irradiation, ultraviolet curing treatment is carried out to obtain a hot melt adhesive film.

[0014] Preferably, as a method for preparing a hot melt adhesive with far-infrared function according to the present invention, the diazotization reaction in S1 includes dissolving 4-cyanoaniline (10 mmol) in 20 mL of 1 M hydrochloric acid in an ice bath, slowly dropping an aqueous solution of sodium nitrite (12 mmol), maintaining the temperature at 0°C - 5°C, and stirring for 15 - 30 minutes.

[0015] Preferably, as a method for preparing a hot melt adhesive with far-infrared function according to the present invention, the coupling reaction in S1 includes dissolving amylphenol (10 mmol) in 50 mL of ethanol, dropping the diazonium salt solution obtained from the diazotization reaction, controlling the pH = 5 - 6, and reacting at room temperature for 3 - 4 hours.

[0016] Preferably, as a method for preparing a hot melt adhesive with far-infrared function according to the present invention, the post-treatment in S1 includes extracting the mixture after the coupling reaction with ethyl acetate, combining the organic phases, drying with anhydrous sodium sulfate, removing the solvent by rotary evaporation, purifying by column chromatography (silica gel, petroleum ether / ethyl acetate = 5:1), collecting the orange band, and obtaining an orange-red crystal.

[0017] Preferably, as a method for preparing a hot melt adhesive with far-infrared function according to the present invention, the introduction of dynamic covalent bonds in S1 includes dissolving Azo-LC and HEMA-Fu in anhydrous THF, adding a DBTDL catalyst (0.1 mmol), protecting with nitrogen, stirring in an oil bath at 60°C for 6 hours, concentrating the reaction solution, precipitating in cold ether, and filtering to obtain a white solid.

[0018] Preferably, as a method for preparing a hot melt adhesive with far-infrared function according to the present invention, the acidification reaction in S2 includes adding GQDs (100 mg) to 20 mL of concentrated nitric acid (65%), refluxing at 80 - 90°C for 12 hours;

[0019] The washing includes centrifuging (12000 rpm, 10 min) to remove the unreacted acid, washing with deionized water until neutral (pH = 7), and drying in vacuum.

[0020] Preferably, as a preparation method of the hot melt adhesive with far-infrared function of the present invention, the ligand exchange in S2 includes adding oleylamine-coated CsPbBr3 (10 mg / mL toluene solution) and mercaptoethylamine (5 mmol) into a Schlenk flask, and shaking for 20 - 24 hours under nitrogen protection;

[0021] The purification includes adding n-hexane for precipitation, centrifuging (7000 - 8000 rpm, 5 - 10 min), and redispersing with toluene to obtain -NH2 modified quantum dots.

[0022] Preferably, as a preparation method of the hot melt adhesive with far-infrared function of the present invention, the hybridization in S2 includes adding carboxylated GQDs and aminated CsPbBr3 (mass ratio 1:2) into 10 mL of DMF, ultrasonicating for 30 minutes, and then centrifuging (10000 rpm, 5 - 10 min) to remove unhybridized particles. The supernatant is the hybrid quantum dot dispersion.

[0023] Preferably, as a preparation method of the hot melt adhesive with far-infrared function of the present invention, the mixing ratio of DA-Azo-LC, hybrid quantum dots, Irgacure 819 and THF in S3 is 50%:15%:2%:33%.

[0024] Preferably, as a preparation method of the hot melt adhesive with far-infrared function of the present invention, the magnetic field strength at the center of the superconducting magnet in S4 is 1 T, and the direction is perpendicular to the base film;

[0025] The blue light parameters are: 450 nm, 50 mW / cm 2 ;

[0026] The ultraviolet light parameters are: 365 nm LED (30 mW / cm 2 ).

[0027] A hot melt adhesive is prepared by using the above-mentioned preparation method of the hot melt adhesive with far-infrared function.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1) In the present invention, the azobenzene group undergoes cis-isomerization under 365 nm ultraviolet light and restores trans-isomerization under 450 nm blue light. This conformational change can dynamically adjust the arrangement density of liquid crystal molecules, thereby changing the absorption and emission efficiency of the material for far-infrared rays;

[0030] 2) By introducing dynamic covalent bonds, Azo-LC and HEMA-Fu are dissolved in THF, and a catalytic amount of DBTDL is added. The reaction is carried out at 60 °C for 6 hours to generate a liquid crystal prepolymer (DA-Azo-LC) containing Diels-Alder dynamic bonds. HEMA-Fu can reversibly break at 60 °C and re-crosslink after cooling. The dynamic reorganization of molecular chains enables the material to self-repair after damage, such as scratch repair, thereby improving the service life of the hot melt adhesive;

[0031] 3) The present invention utilizes the high specific surface area and sp 2 carbon structure of GQDs to enhance the far-infrared radiation efficiency, and the exciton effect of CsPbBr3 to broaden the infrared radiation wavelength range. At the same time, carboxylated graphene quantum dots (GQDs) and amino-functionalized perovskite quantum dots (CsPbBr3) are hybridized through electrostatic interaction to enhance the thermal conductivity. Detailed implementation manners

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] The present invention relates to a hot melt adhesive with far-infrared function and a preparation method thereof, including the following steps:

[0034] S1: Synthesize a photo-responsive liquid crystal monomer;

[0035] After preparing 4-cyano-4'-pentylazobenzene through diazotization reaction, coupling reaction and post-treatment in sequence, introduce dynamic covalent bonds (synthesize DA-Azo-LC);

[0036] S2: Quantum dot functionalization modification;

[0037] Carry out carboxylation treatment of GQDs through acidification reaction and washing in sequence, and then carry out amino modification of CsPbBr3 through ligand exchange and purification. After that, hybridize carboxylated GQDs and amino-functionalized CsPbBr3;

[0038] S3: Preparation and coating of the precursor solution;

[0039] Prepare a precursor solution by stirring and mixing DA-Azo-LC, hybrid quantum dots, Irgacure 819 and THF in proportion, and then drop the precursor solution onto a PI-based film treated with oxygen plasma through a spin coater;

[0040] S4: Magnetic field-light field cooperative orientation and curing;

[0041] The coated base film is placed at the center of a superconducting magnet. After magnetic field-polarized light induction orientation is carried out by turning on polarized blue light irradiation, ultraviolet curing treatment is carried out to obtain a hot melt adhesive film.

[0042] Specifically, in an ice bath, 4-cyanoaniline (10 mmol) is dissolved in 20 mL of 1 M hydrochloric acid, and an aqueous solution of sodium nitrite (12 mmol) is slowly added dropwise while maintaining the temperature at 0 - 5 °C and stirring for 15 - 30 minutes to obtain a diazonium salt solution. Amylphenol (10 mmol) is dissolved in 50 mL of ethanol, and the above diazonium salt solution is added dropwise while controlling the pH = 5 - 6 (adjusted with NaHCO3). After reacting at room temperature for 3 - 4 hours, the product is extracted with ethyl acetate at least three times, dried over anhydrous sodium sulfate, and then purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 5:1) to obtain an orange-red crystal (Azo-LC); the above Azo-LC and 2-hydroxyethyl methacrylate modified with furan groups (HEMA-Fu, molar ratio 1:1) are dissolved in THF, and a catalytic amount of DBTDL (dibutyltin dilaurate) is added, and the reaction is carried out at 60 °C for 6 hours to generate a liquid crystal prepolymer containing Diels-Alder dynamic bonds (DA-Azo-LC); GQDs are dispersed in 20 mL of concentrated nitric acid (65%), refluxed at 80 - 90 °C for 12 hours, centrifuged (12000 rpm, 10 min), washed until neutral (pH = 7), and dried in vacuo. Then, the ligand exchange method is adopted: oleylamine-coated CsPbBr3 (10 mg / mL toluene solution) and 2-mercaptoethylamine (5 mmol) are added to a Schlenk flask, shaken under nitrogen protection for 20 - 24 hours, n-hexane is added, and centrifuged (7000 - 8000 rpm, 5 - 10 min) to obtain -NH2 modified quantum dots. Carboxylated GQDs and amino-functionalized CsPbBr3 (mass ratio 1:2) are ultrasonically mixed in 10 mL of DMF to form a core-shell structure through electrostatic interaction; 50 wt% of the DA-Azo-LC prepolymer, 15 wt% of the GQDs / CsPbBr3 hybrid quantum dots, 2 wt% of a photoinitiator (Irgacure 819), and 33 wt% of tetrahydrofuran (THF) are magnetically stirred in the above components for 6 hours (40 °C) under light-shielded conditions to form a homogeneous transparent solution (i.e., the precursor solution); the precursor solution is spin-coated (rotation speed 2000 rpm, thickness ~50 μm) onto a polyimide (PI) base film whose surface has been treated with oxygen plasma, and then immediately placed at the center of a superconducting magnet (magnetic field strength 1 T, direction perpendicular to the bo film), and at the same time, polarized blue light (450 nm, 50 mW / cm 2) Irradiate for 10 minutes. During this process, the magnetic field induces the alignment of quantum dots along the magnetic field lines (paramagnetism of GQDs), the polarized light excites the cis-trans isomerization of azobenzene molecules, driving the liquid crystal molecules to align orderly along the direction of light polarization. The quantum dots are embedded between the liquid crystal molecules to form a nano-layered structure with alternating "quantum dot - liquid crystal". Finally, under nitrogen protection, it is irradiated with a 365 nm ultraviolet lamp (light intensity 30 mW / cm 2 ) for 15 minutes for curing. After curing, the PI-based film is peeled off to obtain a self-supporting hot melt adhesive film.

[0043] The present invention will be further described below with specific embodiments:

[0044] Example 1:

[0045] In an ice bath, dissolve 4-cyanoaniline (10 mmol) in 20 mL of 1 M hydrochloric acid, slowly add an aqueous solution of sodium nitrite (12 mmol), maintain the temperature at 0 °C, and stir for 30 minutes to obtain a diazonium salt solution. Dissolve pentylphenol (10 mmol) in 50 mL of ethanol, add the above diazonium salt solution dropwise, adjust the pH = 5, and react at room temperature for 4 hours. After extraction with ethyl acetate three times and drying over anhydrous sodium sulfate, purify by column chromatography (silica gel, petroleum ether / ethyl acetate = 5:1) to obtain an orange-red crystal (Azo-LC); dissolve Azo-LC and 2-hydroxyethyl methacrylate modified with a furan group (HEMA-Fu, molar ratio 1:1) in THF, add a catalytic amount of DBTDL (dibutyltin dilaurate), and react at 60 °C for 6 hours to generate a liquid crystal prepolymer containing Diels-Alder dynamic bonds (DA-Azo-LC); disperse GQDs (diameter 3 - 5 nm) in 20 mL of concentrated nitric acid (65%), reflux at 90 °C for 12 hours, centrifuge (12000 rpm, 10 min), wash until neutral (pH = 7), and dry in vacuo. Then, use the ligand exchange method: add oleylamine-coated CsPbBr3 (10 mg / mL toluene solution) and mercaptoethylamine (5 mmol) to a Schlenk flask, shake under nitrogen protection for 24 hours, add n-hexane, and centrifuge (8000 rpm, 10 min) to obtain -NH2 modified quantum dots. Ultrasonically mix carboxylated GQDs (10 mg) and amino-functionalized CsPbBr3 (20 mg) in 10 mL of DMF to form a core-shell structure through electrostatic interaction; magnetically stir the DA-Azo-LC prepolymer: 5 g, GQDs / CsPbBr3 hybrid quantum dots: 1.5 g, photoinitiator (Irgacure 819): 0.2 g, and tetrahydrofuran (THF): 3.3 g in the dark for 6 hours (40 °C) to form a precursor solution; spin-coat the precursor solution on a polyimide (PI) substrate film whose surface has been treated with oxygen plasma by a spin coater (rotation speed 2000 rpm, thickness ~50 μm), and then immediately place it in the center of a superconducting magnet (magnetic field strength 1 T, direction perpendicular to the bo film), and at the same time turn on polarized blue light (450 nm, 50 mW / cm 2 ), irradiate for 10 minutes, and irradiate with a 365 nm ultraviolet lamp (light intensity 30 mW / cm 2 ) for 15 minutes to cure. After curing, peel off the PI substrate film to obtain a self-supporting hot melt adhesive film (thickness about 30 μm).

[0046] Use a blade to make a 1 cm long incision on the film surface, heat it on a 60 °C hot stage for 10 minutes, observe the healing of the incision, and use a universal testing machine to test the tensile strength three times before and after repair, and record the average value;

[0047] Using a Fourier transform infrared spectrometer (equipped with an integrating sphere), the test wavelength range is 6 - 20 μm. Record the emissivity change in the 8 - 14 μm band, and irradiate the sample with 365 nm and 450 nm light sources to conduct a light control experiment and record the average value.

[0048] Example 2:

[0049] In an ice bath, dissolve 4 - cyanoaniline (10 mmol) in 20 mL of 1 M hydrochloric acid, slowly add an aqueous solution of sodium nitrite (12 mmol), maintain the temperature at 5 °C, and stir for 15 minutes to obtain a diazonium salt solution. Dissolve pentylphenol (10 mmol) in 50 mL of ethanol, add the above diazonium salt solution, adjust the pH = 5, react at room temperature for 3 hours, then extract three times with ethyl acetate and dry with anhydrous sodium sulfate, and purify by column chromatography (silica gel, petroleum ether / ethyl acetate = 5:1) to obtain an orange - red crystal (Azo - LC); dissolve Azo - LC and 2 - hydroxyethyl methacrylate modified with furan groups (HEMA - Fu, molar ratio 1:1) in THF, add a catalytic amount of DBTDL (dibutyltin dilaurate), and react at 60 °C for 6 hours to generate a liquid crystal prepolymer containing Diels - Alder dynamic bonds (DA - Azo - LC); disperse GQDs (diameter 3 - 5 nm) in 20 mL of concentrated nitric acid (65%), reflux at 80 °C for 12 hours, centrifuge (12000 rpm, 10 min) and wash until neutral (pH = 7), then dry in vacuum. Then use the ligand exchange method: Add oleylamine - coated CsPbBr3 (10 mg / mL toluene solution) and mercaptoethylamine (5 mmol) to a Schlenk flask, shake for 20 hours under nitrogen protection, add n - hexane, and centrifuge (8000 rpm, 10 min) to obtain - NH2 - modified quantum dots. Ultrasonically mix carboxylated GQDs (15 mg) and amino - functionalized CsPbBr3 (30 mg) in 10 mL of DMF to form a core - shell structure through electrostatic interaction; magnetically stir the DA - Azo - LC prepolymer: 10 g, GQDs / CsPbBr3 hybrid quantum dots: 3 g, photoinitiator (Irgacure 819): 0.4 g, and tetrahydrofuran (THF): 6.6 g in the dark for 6 hours (40 °C) to form a precursor solution; spin - coat the precursor solution on a polyimide (PI) substrate film whose surface has been treated with oxygen plasma by a spin coater (rotation speed 2000 rpm, thickness ~50 μm), then immediately place it at the center of a superconducting magnet (magnetic field strength 1 T, direction perpendicular to the film), and at the same time turn on polarized blue light (450 nm, 50 mW / cm 2 ) and irradiate for 10 minutes. Finally, under nitrogen protection, irradiate with a 365 nm ultraviolet lamp (light intensity 30 mW / cm 2 ) for 15 minutes to cure, and after curing, peel off the PI substrate film to obtain a self - supporting hot - melt adhesive film (thickness about 35 μm).

[0050] Use a blade to make a 1-cm long incision on the film surface, heat it on a hot stage at 60 °C for 10 minutes, observe the healing of the incision, test the tensile strength three times before and after repair using a universal testing machine, and record the average value;

[0051] Using a Fourier transform infrared spectrometer (equipped with an integrating sphere), test the wavelength range of 6 - 20 μm, record the emissivity change in the 8 - 14 μm band, and irradiate the sample with 365 nm and 450 nm light sources to conduct a light control experiment, and record the average value.

[0052] Prepared by traditional process

[0053] Polymer substrate: EVA (ethylene - vinyl acetate, vinyl acetate content 25% - 40%), polyurethane (PU), or polyamide (PA).

[0054] Far - infrared additive: ceramic powders such as alumina (Al2O3), zirconia (ZrO2), or graphene (mass ratio 5% - 15%).

[0055] Auxiliary components: tackifying resin (rosin ester), waxes (microcrystalline wax), antioxidant (such as BHT).

[0056] Comparative example 1:

[0057] Heat the EVA substrate to 180 °C until it melts into a viscous flow state, add the tackifying resin and waxes, stir for 15 minutes (rotation speed 50 - 100 rpm), slowly add the ceramic powder to avoid dusting, continue to stir for 30 minutes until uniform, and keep the temperature not exceeding 200 °C throughout the process to prevent polymer decomposition. Extrude the melt through a twin - screw extruder (length - diameter ratio 32:1), cool it in a water bath and then pelletize (diameter 3 mm), use a mold to extrude it into a rod with a fixed diameter (such as Φ10 mm), and make a hot - melt adhesive with far - infrared function through a calender or pelletizer.

[0058] Use a blade to make a 1 - cm long incision on the film surface, heat it on a hot stage at 60 °C for 10 minutes, observe the healing of the incision, test the tensile strength three times before and after repair using a universal testing machine, and record the average value;

[0059] Using a Fourier transform infrared spectrometer (equipped with an integrating sphere), test the wavelength range of 6 - 20 μm, record the emissivity change in the 8 - 14 μm band, and record the average value;

[0060] The test results are shown in Table 1 and Table 2 as follows:

[0061]

[0062] Table 1

[0063]

[0064] Table 2

[0065] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of hot melt adhesive with far-infrared function, characterized in that, It includes the following steps: S1: Synthesize a light-responsive liquid crystal monomer (Azo-LC); After preparing 4-cyano-4'-pentyl azobenzene through a diazotization reaction, a coupling reaction, and post-treatment in sequence, introduce a dynamic covalent bond (synthesize DA-Azo-LC); S2: Quantum dot functionalization modification; Carry out carboxylation treatment of GQDs through an acidification reaction and washing in sequence, then carry out amino modification of CsPbBr3 through ligand exchange and purification, and then hybridize carboxylated GQDs with amino-functionalized CsPbBr3; S3: Preparation and coating of the precursor solution; Prepare a precursor solution by stirring and mixing DA-Azo-LC, hybrid quantum dots, Irgacure 819, and THF in proportion, and then drip the precursor solution onto a PI-based film treated with oxygen plasma through a spin coater; S4: Magnetic field-light field synergistic alignment and curing; Place the coated base film at the center of a superconducting magnet, turn on polarized blue light irradiation for magnetic field-polarized light-induced orientation, and then carry out ultraviolet curing treatment to obtain a hot melt adhesive film.

2. The preparation method of the hot melt adhesive with far-infrared function according to claim 1, characterized in that: The diazotization reaction in S1 includes dissolving 4-cyanoaniline (10 mmol) in 20 mL of 1 M hydrochloric acid in an ice bath, slowly dripping an aqueous solution of sodium nitrite (12 mmol), maintaining the temperature at 0°C - 5°C, and stirring for 15 - 30 minutes.

3. The preparation method of the hot melt adhesive with far-infrared function according to claim 2, characterized in that: The coupling reaction in S1 includes dissolving pentylphenol (10 mmol) in 50 mL of ethanol, dripping the diazonium salt solution obtained from the diazotization reaction, controlling the pH = 5 - 6, and reacting at room temperature for 3 - 4 hours.

4. The preparation method of the hot melt adhesive with far-infrared function according to claim 3, characterized in that: The post-treatment in S1 includes extracting the mixture after the coupling reaction with ethyl acetate, combining the organic phases, drying with anhydrous sodium sulfate, rotary evaporating to remove the solvent, purifying by column chromatography (silica gel, petroleum ether / ethyl acetate = 5:1), collecting the orange band, and obtaining an orange-red crystal.

5. The preparation method of the hot melt adhesive with far-infrared function according to claim 4, characterized in that: The introduction of the dynamic covalent bond in S1 includes dissolving Azo-LC and HEMA-Fu in anhydrous THF, adding a DBTDL catalyst (0.1 mmol), protecting with nitrogen, stirring in an oil bath at 60°C for 6 hours, concentrating the reaction solution, precipitating in cold ether, and filtering to obtain a white solid.

6. The preparation method of the hot melt adhesive with far-infrared function according to claim 1, characterized in that: The acidification reaction in S2 includes adding GQDs (100 mg) to 20 mL of concentrated nitric acid (65%), refluxing at 80 - 90°C for 12 hours; The washing includes centrifuging (12000 rpm, 10 min) to remove unreacted acid, washing with deionized water until neutral (pH = 7), and vacuum drying.

7. The preparation method of the hot melt adhesive with far-infrared function according to claim 6, characterized in that: The ligand exchange in S2 includes adding oleylamine-coated CsPbBr3 (10 mg / mL toluene solution) and mercaptoethylamine (5 mmol) to a Schlenk flask, and shaking under nitrogen protection for 20 - 24 hours; The purification includes adding n-hexane for precipitation, centrifuging (7000 - 8000 rpm, 5 - 10 min), and redispersing in toluene to obtain -NH2-modified quantum dots; The hybridization includes adding carboxylated GQDs and aminated CsPbBr3 (mass ratio 1:2) to 10 mL of DMF. After ultrasonic treatment for 30 minutes, unhybridized particles are removed by centrifugation (10000 rpm, 5 - 10 min), and the supernatant is the hybrid quantum dot dispersion.

8. The preparation method of the hot melt adhesive with far-infrared function according to claim 1, characterized in that: In the S3, the mixing ratio of DA - Azo - LC, hybrid quantum dots, Irgacure 819 and THF is 50%:15%:2%:33%.

9. The preparation method of the hot melt adhesive with far-infrared function according to claim 1, characterized in that: In the S4, the magnetic field strength at the center of the superconducting magnet is 1 T, and the direction is perpendicular to the base film; The blue light parameters are: 450 nm, 50 mW / cm 2 ; The ultraviolet light parameters are: 365 nm LED (30 mW / cm 2 ).

10. A hot melt adhesive, characterized in that: It is prepared by using the method for preparing a hot - melt adhesive with far - infrared function according to any one of claims 1 - 9.

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