Inorganic nanoparticle composite modified UV-cured acrylic pressure-sensitive adhesive and preparation method thereof

Abstract

The invention discloses an inorganic nanoparticle composite modified UV-cured acrylic pressure-sensitive adhesive and a preparation method thereof, and solves the problems that hollow MgF2 nanoparticles are not uniformly dispersed and the pressure-sensitive adhesive is difficult to consider multiple properties. The method comprises the following steps: activating hollow MgF2 with hydrochloric acid to expose hydroxyl; preparing a modifier containing hydroxyl and side chains, and grafting the modifier to the surfaces of the activated particles through condensation reaction; mixing and dispersing the modified particles, UV-cured acrylic resin and a solvent, and adding a photoinitiator to obtain a prepolymer; and coating to form a 300-350nm coating, and carrying out UV curing to obtain the coating. According to the invention, uniform dispersion of particles is realized through hydrochloric acid activation-polymer grafting, the thickness of the coating is designed, and the prepared pressure-sensitive adhesive has high transparency, excellent wear resistance, high temperature resistance and good adhesion, and is suitable for the fields of high-end optical devices, precision electronics and the like.

Description

Technical Field

[0001] This invention relates to the field of pressure-sensitive adhesive technology, specifically to an inorganic nanoparticle composite modified UV-curable acrylic pressure-sensitive adhesive and its preparation method. Background Technology

[0002] UV-curable acrylic pressure-sensitive adhesives are widely used in packaging, electronics, and optics due to their advantages such as fast curing speed, solvent-free operation, and low energy consumption. However, traditional UV-curable acrylic pressure-sensitive adhesives suffer from problems such as insufficient transparency, poor abrasion resistance, and inadequate high-temperature resistance, which limit their application in high-performance fields such as high-end optical devices and precision electronics.

[0003] MgF2 has a low refractive index (approximately 1.38), and the refractive index of hollow MgF2 nanoparticles can be further reduced. Introducing them into pressure-sensitive adhesives is expected to reduce light reflection and scattering, thereby improving light transmittance. Simultaneously, the addition of inorganic nanoparticles can also enhance the mechanical properties and high-temperature resistance of the pressure-sensitive adhesive.

[0004] However, hollow MgF2 nanoparticles have a highly polar surface, resulting in poor compatibility with organic UV-curable acrylic resin matrices. They are prone to aggregation and difficult to disperse uniformly, which not only fails to achieve their modification effect but may also lead to a decline in the performance of the pressure-sensitive adhesive. Furthermore, the coating thickness of the pressure-sensitive adhesive significantly affects its adhesion and light transmittance; existing technologies struggle to find a coating thickness range that balances good adhesion and high light transmittance. Therefore, achieving uniform dispersion of hollow MgF2 nanoparticles in the pressure-sensitive adhesive matrix, combined with a suitable coating thickness design, to prepare a UV-curable acrylic pressure-sensitive adhesive that combines high transparency, excellent wear resistance, high-temperature resistance, and good adhesion has become a pressing problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an inorganic nanoparticle composite modified UV-curable acrylic pressure-sensitive adhesive and its preparation method, so as to solve the problems of uneven dispersion of hollow MgF2 nanoparticles in pressure-sensitive adhesives and the difficulty of pressure-sensitive adhesives in simultaneously achieving transparency, wear resistance, high temperature resistance and adhesion.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing an inorganic nanoparticle composite modified UV-curable acrylic pressure-sensitive adhesive includes the following steps: S1. Activation of hollow MgF2 nanoparticles: Hollow MgF2 nanoparticles were soaked in a 0.5-2 mol / L hydrochloric acid solution and then washed until neutral to obtain activated hollow MgF2 nanoparticles. S2. Preparation of the modifier: 70-80 parts by weight of butyl acrylate, 20-30 parts by weight of hydroxyethyl acrylate, and 0.7-0.9 parts by weight of azobisisobutyronitrile were added to 250-350 parts by weight of tetrahydrofuran. After purging with nitrogen to remove oxygen, the mixture was reacted at 65-75°C for 5-7 hours. Then, 40-60 parts by weight of methyl methacrylate and 0.4-0.6 parts by weight of azobisisobutyronitrile were added, and the mixture was reacted at 70-80°C for 4-6 hours. The reaction solution was poured into petroleum ether to precipitate the precipitate. The precipitate was filtered, washed, and the modifier was obtained. S3, Modified hollow MgF2 nanoparticles: Add 3-5 parts by weight of activated hollow MgF2 nanoparticles to 8-12 parts by weight of ethyl acetate, and ultrasonically disperse to form a suspension; then add 0.8-1.2 parts by weight of the modifier prepared in step S2 and p-toluenesulfonic acid (the amount is 1%-3% of the weight of the grafted polymer), under nitrogen protection, and stir at 70-90℃ for 4-8 hours; centrifuge, wash, and obtain modified hollow MgF2 nanoparticles; S4. Preparation of pressure-sensitive adhesive: Add 50-80 parts by weight of UV-curable acrylic resin, 5-15 parts by weight of modified hollow MgF2 nanoparticles, and 10-30 parts by weight of solvent, and disperse by high-speed stirring at 1000-2000 r / min for 30-60 min; add 2-4 parts by weight of photoinitiator, and stir at 500-800 r / min for 15-30 min to obtain a prepolymer mixture; S5. Forming of pressure-sensitive adhesive coating: Apply to the surface of the substrate, control the coating thickness to be 300-350nm; cure by UV light for 30-60s to obtain the target pressure-sensitive adhesive coating.

[0007] Activation mechanism: In step S1, 0.5-2 mol / L hydrochloric acid solution can remove impurities and residual salts on the surface of hollow MgF2 nanoparticles. At the same time, through gentle etching, it can destroy some Mg-F bonds on the surface of the particles, exposing more hydroxyl groups (-OH) on the surface, forming activated particles rich in active sites, which provides a chemical basis for subsequent grafting of modifiers.

[0008] The hydroxyethyl acrylate unit in the main chain of the modifier prepared in step S2 contains hydroxyl groups, which can undergo a condensation reaction with the hydroxyl groups on the surface of activated MgF2 under the catalysis of p-toluenesulfonic acid to form a stable -O-covalent bond, so that the modifier is firmly grafted onto the particle surface. The polymethyl methacrylate (PMMA) side chain has a similar structure to the hard monomers (such as methyl methacrylate) in UV-cured acrylic resin. Based on the principle of "like dissolves like", it greatly reduces the interfacial tension between inorganic particles and organic resin matrix, avoids particle agglomeration, and achieves uniform dispersion.

[0009] High transparency is achieved by uniformly dispersed hollow MgF2 nanoparticles with low refractive index (lower than the resin matrix), which reduces light reflection and scattering at the resin-particle interface. At the same time, the coating thickness of 300-350nm is designed according to Fresnel's law. At this thickness, the light reflection loss on the coating surface is minimized, and the decrease in light transmittance caused by multiple reflections of light in thick coatings is avoided. The dual effect significantly improves the visible light transmittance of the pressure-sensitive adhesive.

[0010] Enhanced wear resistance and high temperature resistance: Inorganic hollow MgF2 nanoparticles have a rigid structure and can act as a physical reinforcing phase after uniform dispersion, forming a "rigid support network" in the pressure-sensitive adhesive matrix, reducing coating deformation and wear under external force; at the same time, the thermal stability of inorganic particles is better than that of organic resins, which can suppress the thermal motion of resin molecular chains at high temperatures and improve the high temperature resistance of pressure-sensitive adhesives.

[0011] This is a further optimization of a preparation method for an inorganic nanoparticle composite modified UV-curable acrylic pressure-sensitive adhesive.

[0012] Preferably, the hollow MgF2 nanoparticles have a size of less than 100 nm.

[0013] If the size is too large, it may scatter the incident light, thereby reducing light transmittance.

[0014] Preferably, the UV-curable acrylic resin in step S4 is a copolymer of soft monomers, hard monomers, and functional monomers, with a weight ratio of soft monomers:hard monomers:functional monomers = 60-80:20-30:5-10. The soft monomers provide viscosity and flexibility and are selected from at least one of butyl acrylate and isooctyl acrylate; the hard monomers enhance cohesion and mechanical strength and are selected from at least one of methyl methacrylate and styrene; the functional monomers introduce active groups and enhance bonding strength and are selected from at least one of hydroxyethyl acrylate and acrylic acid.

[0015] Preferably, the photoinitiator in step S4 is 1-hydroxycyclohexylphenyl ketone; Preferably, the solvent in step S4 is ethyl acetate.

[0016] Preferably, in step S5, the substrate is a PET film.

[0017] The inorganic nanoparticle composite modified UV-curable acrylic pressure-sensitive adhesive was prepared according to the above preparation method.

[0018] The advantages of this invention compared to the prior art are as follows: (1) Solving the dispersion problem of hollow MgF2 nanoparticles and laying the foundation for performance improvement. Through a two-step modification strategy of "hydrochloric acid activation-polymer grafting", the compatibility between inorganic nanoparticles and organic resins is fundamentally improved. Hydrochloric acid activation can remove impurities on the particle surface and expose hydroxyl active sites, providing a chemical basis for subsequent grafting; the self-made modifier significantly reduces interfacial tension through hydroxyl condensation reaction, completely avoids particle agglomeration, realizes uniform dispersion of hollow MgF2 in resin, and ensures that the modification effect is fully exerted.

[0019] (2) Achieving a synergistic balance between high transparency and good adhesion, this invention breaks through the traditional problem of balancing transparency and adhesion of pressure-sensitive adhesives through dual regulation of "dispersion optimization + thickness design": uniformly dispersed low-refractive-index hollow MgF2 nanoparticles can reduce the reflection and scattering of light at the resin-particle interface; the coating thickness of 300-350nm is designed according to Fresnel's law, which avoids insufficient adhesion of thin coatings and prevents the light transmittance of thick coatings from decreasing due to multiple reflections, ultimately significantly improving the visible light transmittance of pressure-sensitive adhesives while maintaining stable adhesion performance.

[0020] (3) Significantly enhances wear resistance and high temperature resistance. The synergistic effect of inorganic nanoparticles and organic matrix greatly improves the mechanical and thermal stability of pressure-sensitive adhesive: The uniformly dispersed hollow MgF2 nanoparticles, as a "rigid support phase", can effectively resist coating deformation and wear under external force; the high heat resistance of inorganic particles can inhibit the thermal motion of resin molecular chains at high temperature and improve the high temperature resistance of pressure-sensitive adhesive. Attached Figure Description

[0021] Figure 1 These are scanning electron microscope images of the pressure-sensitive adhesive prepared in Example 1 applied to a substrate; Figure 2 (a)-(b) are transmission electron microscope images of hollow MgF2 nanoparticles and modified Example 1, respectively; Figure 3 (a) and (b) are respectively the scratches on the coatings of Example 1 and Comparative Example 2 by a 3H hardness pencil observed under an optical microscope. Figure 4 This is a bar graph showing the peel force of the pressure-sensitive adhesives prepared in Examples 1-3 and Comparative Examples 2-5 before and after 2 hours at 180°C; Figure 5 These are the transmittance curves for Example 1, Comparative Example 2, and the PET substrate; Figure 6 These are the transmittance curves for Examples 1, 4, 4, and 5. Detailed Implementation

[0022] To make the above-mentioned objectives, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to examples. The following content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not deviate from the concept of the invention, they should all fall within the protection scope of the present invention.

[0023] The preparation method of the present invention will be described below through specific embodiments and comparative examples.

[0024] Example 1 A method for preparing an inorganic nanoparticle composite modified UV-curable acrylic pressure-sensitive adhesive includes the following steps: S1. Activation of hollow MgF2 nanoparticles: Hollow MgF2 nanoparticles were soaked in a 0.5 mol / L hydrochloric acid solution and then washed until neutral to obtain activated hollow MgF2 nanoparticles. S2. Preparation of the modifier: 75 parts by mass of butyl acrylate, 25 parts by mass of hydroxyethyl acrylate, and 0.8 parts by mass of azobisisobutyronitrile were added to 300 parts by mass of tetrahydrofuran. After purging with nitrogen to remove oxygen, the mixture was reacted at 70°C for 6 hours. Then, 50 parts by mass of methyl methacrylate and 0.5 parts by mass of azobisisobutyronitrile were added, and the mixture was reacted at 75°C for 5 hours. The reaction solution was poured into petroleum ether to precipitate, filtered, and washed to obtain the modifier. S3, Modified hollow MgF2 nanoparticles: 4 parts by mass of activated hollow MgF2 nanoparticles were added to 10 parts by mass of ethyl acetate and ultrasonically dispersed to form a suspension; then 1 part by mass of the modifier prepared in step S2 and p-toluenesulfonic acid (1% of the weight of the grafted polymer) were added, and the mixture was stirred at 70°C for 4 hours under nitrogen protection; after centrifugation and washing, modified hollow MgF2 nanoparticles were obtained. S4. Preparation of pressure-sensitive adhesive: Add 50 parts by weight of UV-curable acrylic resin, 5 parts by weight of modified hollow MgF2 nanoparticles, and 10 parts by weight of solvent, and disperse by high-speed stirring at 1000 r / min for 30 min; add 2 parts by weight of photoinitiator, and stir at 500 r / min for 15 min to obtain a prepolymer mixture. S5. Forming of pressure-sensitive adhesive coating: Apply to the surface of the substrate, control the coating thickness to 300nm; cure by UV light for 30s to obtain the target pressure-sensitive adhesive coating.

[0025] In step S4, the UV-curable acrylic resin is a copolymer of soft monomers, hard monomers, and functional monomers, with a weight ratio of soft monomers:hard monomers:functional monomers = 60:20:5. The soft monomer is butyl acrylate; the hard monomer is methyl methacrylate; and the functional monomer is hydroxyethyl acrylate. The photoinitiator in step S4 is 1-hydroxycyclohexylphenyl ketone; the solvent in step S4 is ethyl acetate; and in step S5, the substrate is a PET film.

[0026] Example 2 A method for preparing an inorganic nanoparticle composite modified UV-curable acrylic pressure-sensitive adhesive includes the following steps: S1. Activation of hollow MgF2 nanoparticles: Hollow MgF2 nanoparticles were soaked in a 1 mol / L hydrochloric acid solution and then washed until neutral to obtain activated hollow MgF2 nanoparticles. S2. Preparation of the modifier: 70 parts by mass of butyl acrylate, 20 parts by mass of hydroxyethyl acrylate, and 0.7 parts by mass of azobisisobutyronitrile were added to 250 parts by mass of tetrahydrofuran. After purging with nitrogen to remove oxygen, the mixture was reacted at 65°C for 5 hours. Then, 40 parts by mass of methyl methacrylate and 0.4 parts by mass of azobisisobutyronitrile were added, and the mixture was reacted at 70°C for 4 hours. The reaction solution was poured into petroleum ether to precipitate, filtered, and washed to obtain the modifier. S3, Modified hollow MgF2 nanoparticles: 3 parts by mass of activated hollow MgF2 nanoparticles were added to 8 parts by mass of ethyl acetate and ultrasonically dispersed to form a suspension; then 0.8 parts by mass of the modifier prepared in step S2 and p-toluenesulfonic acid (2% of the weight of the grafted polymer) were added, and the mixture was stirred at 80°C for 6 hours under nitrogen protection; after centrifugation and washing, modified hollow MgF2 nanoparticles were obtained. S4. Preparation of pressure-sensitive adhesive: Add 65 parts by weight of UV-curable acrylic resin, 10 parts by weight of modified hollow MgF2 nanoparticles, and 20 parts by weight of solvent, and disperse by high-speed stirring at 1500 r / min for 45 min; add 3 parts by weight of photoinitiator, and stir at 650 r / min for 20 min to obtain a prepolymer mixture. S5. Forming of pressure-sensitive adhesive coating: Apply to the surface of the substrate, control the coating thickness to 320nm; cure by UV light for 45s to obtain the target pressure-sensitive adhesive coating.

[0027] In step S4, the UV-curable acrylic resin is a copolymer of soft monomers, hard monomers, and functional monomers, with a weight ratio of soft monomers:hard monomers:functional monomers = 70:25:8. The soft monomer is isooctyl acrylate; the hard monomer is styrene; and the functional monomer is acrylic acid. The photoinitiator in step S4 is 1-hydroxycyclohexylphenyl ketone; the solvent in step S4 is ethyl acetate; and in step S5, the substrate is a PET film.

[0028] Example 3 A method for preparing an inorganic nanoparticle composite modified UV-curable acrylic pressure-sensitive adhesive includes the following steps: S1. Activation of hollow MgF2 nanoparticles: Hollow MgF2 nanoparticles were soaked in a 2 mol / L hydrochloric acid solution and then washed until neutral to obtain activated hollow MgF2 nanoparticles. S2. Preparation of the modifier: 80 parts by mass of butyl acrylate, 30 parts by mass of hydroxyethyl acrylate, and 0.9 parts by mass of azobisisobutyronitrile were added to 350 parts by mass of tetrahydrofuran. After purging with nitrogen to remove oxygen, the mixture was reacted at 75°C for 7 hours. Then, 60 parts by mass of methyl methacrylate and 0.6 parts by mass of azobisisobutyronitrile were added, and the mixture was reacted at 80°C for 6 hours. The reaction solution was poured into petroleum ether to precipitate, filtered, and washed to obtain the modifier. S3, Modified hollow MgF2 nanoparticles: 5 parts by mass of activated hollow MgF2 nanoparticles were added to 12 parts by mass of ethyl acetate and ultrasonically dispersed to form a suspension; then 1.2 parts by mass of the modifier prepared in step S2 and p-toluenesulfonic acid (3% of the weight of the grafted polymer) were added, and the mixture was stirred at 90°C for 8 hours under nitrogen protection; after centrifugation and washing, modified hollow MgF2 nanoparticles were obtained. S4. Preparation of pressure-sensitive adhesive: Add 80 parts by weight of UV-curable acrylic resin, 15 parts by weight of modified hollow MgF2 nanoparticles, and 30 parts by weight of solvent, and disperse by high-speed stirring at 2000 r / min for 60 min; add 4 parts by weight of photoinitiator, and stir at 800 r / min for 30 min to obtain a prepolymer mixture. S5. Forming of pressure-sensitive adhesive coating: Apply to the surface of the substrate, control the coating thickness to 350nm; cure by UV light for 60s to obtain the target pressure-sensitive adhesive coating.

[0029] In step S4, the UV-curable acrylic resin is a copolymer of soft monomers, hard monomers, and functional monomers, with a weight ratio of soft monomers:hard monomers:functional monomers = 80:30:10. The soft monomer is butyl acrylate; the hard monomer is methyl methacrylate; and the functional monomer is hydroxyethyl acrylate. The photoinitiator in step S4 is 1-hydroxycyclohexylphenyl ketone; the solvent in step S4 is ethyl acetate; and in step S5, the substrate is a PET film.

[0030] Example 4 The difference between this embodiment and Embodiment 1 is that the coating thickness in step S5 is 350 nm, while the remaining steps and parameters are the same as in Embodiment 1.

[0031] Comparative Example 1 In the preparation of the pressure-sensitive adhesive, steps S1 (activation) and S3 (modification) are omitted. Four parts by weight of untreated 80nm hollow MgF2 nanoparticles are directly added to the pressure-sensitive adhesive preparation system. The remaining steps (except for the preparation of the modifier, which is not required) and parameters are the same as in Example 1.

[0032] Comparative Example 2 No hollow MgF2 nanoparticles were added during the preparation of the pressure-sensitive adhesive, and the remaining steps and parameters were the same as in Example 1.

[0033] Comparative Example 3 The coating thickness was adjusted to 150 nm during the preparation of the pressure-sensitive adhesive, and the remaining steps and parameters were the same as in Example 1.

[0034] Comparative Example 4 The coating thickness was adjusted to 250 nm during the preparation of the pressure-sensitive adhesive, and the remaining steps and parameters were the same as in Example 1.

[0035] Comparative Example 5 The coating thickness was adjusted to 400 nm during the preparation of the pressure-sensitive adhesive, and the remaining steps and parameters were the same as in Example 1.

[0036] The pressure-sensitive adhesive prepared in Example 1 was transparent and free of turbidity; the pressure-sensitive adhesive prepared in Comparative Example 1 was milky white and turbid. This is because the particles in Example 1 were uniformly dispersed without agglomeration or precipitation, while the unmodified particles in Comparative Example 1 agglomerated, resulting in a size far exceeding the wavelength of visible light, causing severe light scattering, leading to a sharp drop in transmittance, and the pressure-sensitive adhesive appeared milky white and turbid.

[0037] Figure 1 This is a scanning electron microscope (SEM) image of the pressure-sensitive adhesive coating from Example 1. It shows no obvious particle agglomeration within the coating, and the hollow MgF2 nanoparticles are uniformly distributed at the nanoscale. This demonstrates the effectiveness of the "hydrochloric acid activation-polymer grafting" modification strategy. The modifier is covalently grafted onto the particle surface, reducing interfacial tension and achieving uniform dispersion, laying the foundation for subsequent performance improvements.

[0038] Figure 2 shows transmission electron microscope (TEM) images of unmodified hollow MgF2 nanoparticles (a) and modified hollow MgF2 nanoparticles (b) from Example 1. Figure 2 (a) No coating was observed on the surface of the unmodified particles, the particle size was 20~60nm, and the edges were clear; Figure 2 (b) The modified particles are coated with a uniform polymer film (modifier layer), with a particle size slightly larger than the unmodified particles. This visually demonstrates that the modifier was successfully grafted onto the particle surface. Hydrochloric acid activation exposes hydroxyl groups on the particle surface, which then undergo a condensation reaction with the hydroxyl groups in the modifier to form stable covalent bonds, completing the organic modification of the inorganic particles and solving the compatibility problem.

[0039] Figures 3(a) and 3(b) show the scratches left by a 3H hardness pencil on the coatings of Example 1 and Comparative Example 2, respectively, observed under an optical microscope. The scratches on the coating of Example 1 are shallow and narrow, while the scratches on the coating of Comparative Example 2 (without nanoparticles) are deep and wide. Hollow MgF2 nanoparticles form a "rigid support network" in the matrix, enhancing the mechanical strength of the coating and reducing deformation and wear under external forces.

[0040] Figure 4 The bar graphs show the peel force of the pressure-sensitive adhesives in Examples 1-3 and Comparative Examples 2-5 before and after 180℃ / 2h. Comparing Examples 1-3 with Comparative Example 2, it can be seen that the peel force of Examples 1-3 decreased less after high-temperature treatment, while that of Comparative Example 2 decreased significantly. This is because the high heat resistance of the inorganic particles inhibits the high-temperature thermal motion of the resin molecular chains, thus improving thermal stability.

[0041] Furthermore, the adhesion of the coating with a thickness of 300-350 nm is close to that of the coating without added particles, indicating that the coating possesses both adhesion and heat resistance. The thin coating (150 nm) has insufficient adhesion area and therefore lower peel strength.

[0042] Figure 5 Transmittance curves of Example 1, Comparative Example 2, and PET substrate; It can be seen that the transmittance of Example 1 is significantly higher than that of Comparative Example 2 and PET substrate. This is because the refractive index of hollow MgF2 particles is small, which can reduce the overall refractive index of the coating and thus increase the transmittance of the coating. In addition, the thickness of the coating satisfies Fresnel's law of reflection, which can reduce reflected light and increase transmittance through the destructive interference of light.

[0043] Figure 6 Transmittance curves for Examples 1, 4, 4 (Comparative Example), and 5; it can be seen that the transmittance of Examples 1 and 4 is higher than that of Comparative Examples 4 and 5. This indicates that the coating thickness needs to meet a certain wavelength range to achieve high transmittance. The results show that the transmittance is higher when the coating thickness is 300~350nm.

[0044] In addition, a lower coating thickness of 150 nm (Comparative Example 3) also exhibits high transmittance, but poor adhesion. To achieve both high transmittance and good adhesion, a coating thickness of 300–350 nm was selected.

Claims

1. A method for preparing an inorganic nanoparticle composite modified UV-curable acrylic pressure-sensitive adhesive, characterized in that, Includes the following steps: S1. Activation of hollow MgF2 nanoparticles: Hollow MgF2 nanoparticles are soaked in hydrochloric acid solution to obtain activated hollow MgF2 nanoparticles. S2. Preparation of the modifier: 70-80 parts by weight of butyl acrylate, 20-30 parts by weight of hydroxyethyl acrylate, and 0.7-0.9 parts by weight of azobisisobutyronitrile are added to 250-350 parts by weight of tetrahydrofuran, and nitrogen gas is introduced. The mixture is reacted at 65-75℃ for 5-7 hours. Then, 40-60 parts by weight of methyl methacrylate and 0.4-0.6 parts by weight of azobisisobutyronitrile are added, and the mixture is reacted at 70-80℃ for 4-6 hours. After purification, the modifier is obtained. S3, Modified hollow MgF2 nanoparticles: 3-5 parts by weight of activated hollow MgF2 nanoparticles are added to 8-12 parts by weight of ethyl acetate and ultrasonically dispersed; then 0.8-1.2 parts by weight of the modifier prepared in step S2 and p-toluenesulfonic acid are added, wherein the amount of p-toluenesulfonic acid is 1%-3% of the weight of the modifier, and the mixture is stirred at 70-90℃ for 4-8 hours under nitrogen protection. Centrifugation and washing yielded modified hollow MgF2 nanoparticles. S4. Preparation of pressure-sensitive adhesive: Add 50-80 parts by weight of UV-curable acrylic resin, 5-15 parts by weight of modified hollow MgF2 nanoparticles, and 10-30 parts by weight of solvent, and stir for 30-60 min; add 2-4 parts by weight of photoinitiator, and stir for 15-30 min to obtain a prepolymer mixture. S5. Forming of pressure-sensitive adhesive coating: The prepolymer mixture is coated on the surface of the substrate, and the coating thickness is controlled to be 300-350nm; after curing by UV light for 30-60s, the target pressure-sensitive adhesive coating is obtained.

2. The preparation method according to claim 1, characterized in that, The size of the hollow MgF2 nanoparticles described in step S1 is less than 100 nm.

3. The preparation method according to claim 1, characterized in that, The UV-curable acrylic resin in step S4 is a copolymer of soft monomers, hard monomers and functional monomers, with a weight ratio of soft monomers:hard monomers:functional monomers = 60-80:20-30:5-10; the soft monomers are selected from at least one of butyl acrylate and isooctyl acrylate; the hard monomers are selected from at least one of methyl methacrylate and styrene; and the functional monomers are selected from at least one of hydroxyethyl acrylate and acrylic acid.

4. The preparation method according to claim 1, characterized in that, The photoinitiator mentioned in step S4 is 1-hydroxycyclohexylphenyl ketone.

5. The preparation method according to claim 1, characterized in that, The solvent mentioned in step S4 is ethyl acetate.

6. The preparation method according to claim 1, characterized in that, In step S5, the substrate is a PET film.

7. An inorganic nanoparticle composite modified UV-curable acrylic pressure-sensitive adhesive prepared by any one of the preparation methods described in claims 1-6.

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